1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are suppose to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef _SQLITE3_H_ 34#define _SQLITE3_H_ 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Add the ability to override 'extern' 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51 52#ifndef SQLITE_API 53# define SQLITE_API 54#endif 55 56 57/* 58** These no-op macros are used in front of interfaces to mark those 59** interfaces as either deprecated or experimental. New applications 60** should not use deprecated interfaces - they are support for backwards 61** compatibility only. Application writers should be aware that 62** experimental interfaces are subject to change in point releases. 63** 64** These macros used to resolve to various kinds of compiler magic that 65** would generate warning messages when they were used. But that 66** compiler magic ended up generating such a flurry of bug reports 67** that we have taken it all out and gone back to using simple 68** noop macros. 69*/ 70#define SQLITE_DEPRECATED 71#define SQLITE_EXPERIMENTAL 72 73/* 74** Ensure these symbols were not defined by some previous header file. 75*/ 76#ifdef SQLITE_VERSION 77# undef SQLITE_VERSION 78#endif 79#ifdef SQLITE_VERSION_NUMBER 80# undef SQLITE_VERSION_NUMBER 81#endif 82 83/* 84** CAPI3REF: Compile-Time Library Version Numbers 85** 86** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 87** evaluates to a string literal that is the SQLite version in the 88** format "X.Y.Z" where X is the major version number (always 3 for 89** SQLite3) and Y is the minor version number and Z is the release number.)^ 90** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 91** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 92** numbers used in [SQLITE_VERSION].)^ 93** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 94** be larger than the release from which it is derived. Either Y will 95** be held constant and Z will be incremented or else Y will be incremented 96** and Z will be reset to zero. 97** 98** Since version 3.6.18, SQLite source code has been stored in the 99** <a href="http://www.fossil-scm.org/">Fossil configuration management 100** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 101** a string which identifies a particular check-in of SQLite 102** within its configuration management system. ^The SQLITE_SOURCE_ID 103** string contains the date and time of the check-in (UTC) and an SHA1 104** hash of the entire source tree. 105** 106** See also: [sqlite3_libversion()], 107** [sqlite3_libversion_number()], [sqlite3_sourceid()], 108** [sqlite_version()] and [sqlite_source_id()]. 109*/ 110#define SQLITE_VERSION "3.7.4" 111#define SQLITE_VERSION_NUMBER 3007004 112#define SQLITE_SOURCE_ID "2011-02-23 14:33:31 8609a15dfad23a7c5311b52617d5c4818c0b8d1e" 113 114/* 115** CAPI3REF: Run-Time Library Version Numbers 116** KEYWORDS: sqlite3_version, sqlite3_sourceid 117** 118** These interfaces provide the same information as the [SQLITE_VERSION], 119** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 120** but are associated with the library instead of the header file. ^(Cautious 121** programmers might include assert() statements in their application to 122** verify that values returned by these interfaces match the macros in 123** the header, and thus insure that the application is 124** compiled with matching library and header files. 125** 126** <blockquote><pre> 127** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 128** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 129** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 130** </pre></blockquote>)^ 131** 132** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 133** macro. ^The sqlite3_libversion() function returns a pointer to the 134** to the sqlite3_version[] string constant. The sqlite3_libversion() 135** function is provided for use in DLLs since DLL users usually do not have 136** direct access to string constants within the DLL. ^The 137** sqlite3_libversion_number() function returns an integer equal to 138** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 139** a pointer to a string constant whose value is the same as the 140** [SQLITE_SOURCE_ID] C preprocessor macro. 141** 142** See also: [sqlite_version()] and [sqlite_source_id()]. 143*/ 144SQLITE_API SQLITE_EXTERN const char sqlite3_version[]; 145SQLITE_API const char *sqlite3_libversion(void); 146SQLITE_API const char *sqlite3_sourceid(void); 147SQLITE_API int sqlite3_libversion_number(void); 148 149/* 150** CAPI3REF: Run-Time Library Compilation Options Diagnostics 151** 152** ^The sqlite3_compileoption_used() function returns 0 or 1 153** indicating whether the specified option was defined at 154** compile time. ^The SQLITE_ prefix may be omitted from the 155** option name passed to sqlite3_compileoption_used(). 156** 157** ^The sqlite3_compileoption_get() function allows iterating 158** over the list of options that were defined at compile time by 159** returning the N-th compile time option string. ^If N is out of range, 160** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 161** prefix is omitted from any strings returned by 162** sqlite3_compileoption_get(). 163** 164** ^Support for the diagnostic functions sqlite3_compileoption_used() 165** and sqlite3_compileoption_get() may be omitted by specifying the 166** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 167** 168** See also: SQL functions [sqlite_compileoption_used()] and 169** [sqlite_compileoption_get()] and the [compile_options pragma]. 170*/ 171#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 172SQLITE_API int sqlite3_compileoption_used(const char *zOptName); 173SQLITE_API const char *sqlite3_compileoption_get(int N); 174#endif 175 176/* 177** CAPI3REF: Test To See If The Library Is Threadsafe 178** 179** ^The sqlite3_threadsafe() function returns zero if and only if 180** SQLite was compiled mutexing code omitted due to the 181** [SQLITE_THREADSAFE] compile-time option being set to 0. 182** 183** SQLite can be compiled with or without mutexes. When 184** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 185** are enabled and SQLite is threadsafe. When the 186** [SQLITE_THREADSAFE] macro is 0, 187** the mutexes are omitted. Without the mutexes, it is not safe 188** to use SQLite concurrently from more than one thread. 189** 190** Enabling mutexes incurs a measurable performance penalty. 191** So if speed is of utmost importance, it makes sense to disable 192** the mutexes. But for maximum safety, mutexes should be enabled. 193** ^The default behavior is for mutexes to be enabled. 194** 195** This interface can be used by an application to make sure that the 196** version of SQLite that it is linking against was compiled with 197** the desired setting of the [SQLITE_THREADSAFE] macro. 198** 199** This interface only reports on the compile-time mutex setting 200** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 201** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 202** can be fully or partially disabled using a call to [sqlite3_config()] 203** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 204** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 205** sqlite3_threadsafe() function shows only the compile-time setting of 206** thread safety, not any run-time changes to that setting made by 207** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 208** is unchanged by calls to sqlite3_config().)^ 209** 210** See the [threading mode] documentation for additional information. 211*/ 212SQLITE_API int sqlite3_threadsafe(void); 213 214/* 215** CAPI3REF: Database Connection Handle 216** KEYWORDS: {database connection} {database connections} 217** 218** Each open SQLite database is represented by a pointer to an instance of 219** the opaque structure named "sqlite3". It is useful to think of an sqlite3 220** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 221** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 222** is its destructor. There are many other interfaces (such as 223** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 224** [sqlite3_busy_timeout()] to name but three) that are methods on an 225** sqlite3 object. 226*/ 227typedef struct sqlite3 sqlite3; 228 229/* 230** CAPI3REF: 64-Bit Integer Types 231** KEYWORDS: sqlite_int64 sqlite_uint64 232** 233** Because there is no cross-platform way to specify 64-bit integer types 234** SQLite includes typedefs for 64-bit signed and unsigned integers. 235** 236** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 237** The sqlite_int64 and sqlite_uint64 types are supported for backwards 238** compatibility only. 239** 240** ^The sqlite3_int64 and sqlite_int64 types can store integer values 241** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 242** sqlite3_uint64 and sqlite_uint64 types can store integer values 243** between 0 and +18446744073709551615 inclusive. 244*/ 245#ifdef SQLITE_INT64_TYPE 246 typedef SQLITE_INT64_TYPE sqlite_int64; 247 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 248#elif defined(_MSC_VER) || defined(__BORLANDC__) 249 typedef __int64 sqlite_int64; 250 typedef unsigned __int64 sqlite_uint64; 251#else 252 typedef long long int sqlite_int64; 253 typedef unsigned long long int sqlite_uint64; 254#endif 255typedef sqlite_int64 sqlite3_int64; 256typedef sqlite_uint64 sqlite3_uint64; 257 258/* 259** If compiling for a processor that lacks floating point support, 260** substitute integer for floating-point. 261*/ 262#ifdef SQLITE_OMIT_FLOATING_POINT 263# define double sqlite3_int64 264#endif 265 266/* 267** CAPI3REF: Closing A Database Connection 268** 269** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 270** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 271** successfully destroyed and all associated resources are deallocated. 272** 273** Applications must [sqlite3_finalize | finalize] all [prepared statements] 274** and [sqlite3_blob_close | close] all [BLOB handles] associated with 275** the [sqlite3] object prior to attempting to close the object. ^If 276** sqlite3_close() is called on a [database connection] that still has 277** outstanding [prepared statements] or [BLOB handles], then it returns 278** SQLITE_BUSY. 279** 280** ^If [sqlite3_close()] is invoked while a transaction is open, 281** the transaction is automatically rolled back. 282** 283** The C parameter to [sqlite3_close(C)] must be either a NULL 284** pointer or an [sqlite3] object pointer obtained 285** from [sqlite3_open()], [sqlite3_open16()], or 286** [sqlite3_open_v2()], and not previously closed. 287** ^Calling sqlite3_close() with a NULL pointer argument is a 288** harmless no-op. 289*/ 290SQLITE_API int sqlite3_close(sqlite3 *); 291 292/* 293** The type for a callback function. 294** This is legacy and deprecated. It is included for historical 295** compatibility and is not documented. 296*/ 297typedef int (*sqlite3_callback)(void*,int,char**, char**); 298 299/* 300** CAPI3REF: One-Step Query Execution Interface 301** 302** The sqlite3_exec() interface is a convenience wrapper around 303** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 304** that allows an application to run multiple statements of SQL 305** without having to use a lot of C code. 306** 307** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 308** semicolon-separate SQL statements passed into its 2nd argument, 309** in the context of the [database connection] passed in as its 1st 310** argument. ^If the callback function of the 3rd argument to 311** sqlite3_exec() is not NULL, then it is invoked for each result row 312** coming out of the evaluated SQL statements. ^The 4th argument to 313** to sqlite3_exec() is relayed through to the 1st argument of each 314** callback invocation. ^If the callback pointer to sqlite3_exec() 315** is NULL, then no callback is ever invoked and result rows are 316** ignored. 317** 318** ^If an error occurs while evaluating the SQL statements passed into 319** sqlite3_exec(), then execution of the current statement stops and 320** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 321** is not NULL then any error message is written into memory obtained 322** from [sqlite3_malloc()] and passed back through the 5th parameter. 323** To avoid memory leaks, the application should invoke [sqlite3_free()] 324** on error message strings returned through the 5th parameter of 325** of sqlite3_exec() after the error message string is no longer needed. 326** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 327** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 328** NULL before returning. 329** 330** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 331** routine returns SQLITE_ABORT without invoking the callback again and 332** without running any subsequent SQL statements. 333** 334** ^The 2nd argument to the sqlite3_exec() callback function is the 335** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 336** callback is an array of pointers to strings obtained as if from 337** [sqlite3_column_text()], one for each column. ^If an element of a 338** result row is NULL then the corresponding string pointer for the 339** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 340** sqlite3_exec() callback is an array of pointers to strings where each 341** entry represents the name of corresponding result column as obtained 342** from [sqlite3_column_name()]. 343** 344** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 345** to an empty string, or a pointer that contains only whitespace and/or 346** SQL comments, then no SQL statements are evaluated and the database 347** is not changed. 348** 349** Restrictions: 350** 351** <ul> 352** <li> The application must insure that the 1st parameter to sqlite3_exec() 353** is a valid and open [database connection]. 354** <li> The application must not close [database connection] specified by 355** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 356** <li> The application must not modify the SQL statement text passed into 357** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 358** </ul> 359*/ 360SQLITE_API int sqlite3_exec( 361 sqlite3*, /* An open database */ 362 const char *sql, /* SQL to be evaluated */ 363 int (*callback)(void*,int,char**,char**), /* Callback function */ 364 void *, /* 1st argument to callback */ 365 char **errmsg /* Error msg written here */ 366); 367 368/* 369** CAPI3REF: Result Codes 370** KEYWORDS: SQLITE_OK {error code} {error codes} 371** KEYWORDS: {result code} {result codes} 372** 373** Many SQLite functions return an integer result code from the set shown 374** here in order to indicates success or failure. 375** 376** New error codes may be added in future versions of SQLite. 377** 378** See also: [SQLITE_IOERR_READ | extended result codes] 379*/ 380#define SQLITE_OK 0 /* Successful result */ 381/* beginning-of-error-codes */ 382#define SQLITE_ERROR 1 /* SQL error or missing database */ 383#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 384#define SQLITE_PERM 3 /* Access permission denied */ 385#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 386#define SQLITE_BUSY 5 /* The database file is locked */ 387#define SQLITE_LOCKED 6 /* A table in the database is locked */ 388#define SQLITE_NOMEM 7 /* A malloc() failed */ 389#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 390#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 391#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 392#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 393#define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ 394#define SQLITE_FULL 13 /* Insertion failed because database is full */ 395#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 396#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 397#define SQLITE_EMPTY 16 /* Database is empty */ 398#define SQLITE_SCHEMA 17 /* The database schema changed */ 399#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 400#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 401#define SQLITE_MISMATCH 20 /* Data type mismatch */ 402#define SQLITE_MISUSE 21 /* Library used incorrectly */ 403#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 404#define SQLITE_AUTH 23 /* Authorization denied */ 405#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 406#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 407#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 408// Begin Android Add 409#define SQLITE_UNCLOSED 27 /* db can't be closed due unfinalized stmts */ 410// End Android Add 411#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 412#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 413/* end-of-error-codes */ 414 415/* 416** CAPI3REF: Extended Result Codes 417** KEYWORDS: {extended error code} {extended error codes} 418** KEYWORDS: {extended result code} {extended result codes} 419** 420** In its default configuration, SQLite API routines return one of 26 integer 421** [SQLITE_OK | result codes]. However, experience has shown that many of 422** these result codes are too coarse-grained. They do not provide as 423** much information about problems as programmers might like. In an effort to 424** address this, newer versions of SQLite (version 3.3.8 and later) include 425** support for additional result codes that provide more detailed information 426** about errors. The extended result codes are enabled or disabled 427** on a per database connection basis using the 428** [sqlite3_extended_result_codes()] API. 429** 430** Some of the available extended result codes are listed here. 431** One may expect the number of extended result codes will be expand 432** over time. Software that uses extended result codes should expect 433** to see new result codes in future releases of SQLite. 434** 435** The SQLITE_OK result code will never be extended. It will always 436** be exactly zero. 437*/ 438#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 439#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 440#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 441#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 442#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 443#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 444#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 445#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 446#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 447#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 448#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 449#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 450#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 451#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 452#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 453#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 454#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 455#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 456#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 457#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 458#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 459#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 460#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 461 462/* 463** CAPI3REF: Flags For File Open Operations 464** 465** These bit values are intended for use in the 466** 3rd parameter to the [sqlite3_open_v2()] interface and 467** in the 4th parameter to the xOpen method of the 468** [sqlite3_vfs] object. 469*/ 470#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 471#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 472#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 473#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 474#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 475#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 476#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 477#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 478#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 479#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 480#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 481#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 482#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 483#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 484#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 485#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 486#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 487#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 488 489/* 490** CAPI3REF: Device Characteristics 491** 492** The xDeviceCharacteristics method of the [sqlite3_io_methods] 493** object returns an integer which is a vector of the these 494** bit values expressing I/O characteristics of the mass storage 495** device that holds the file that the [sqlite3_io_methods] 496** refers to. 497** 498** The SQLITE_IOCAP_ATOMIC property means that all writes of 499** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 500** mean that writes of blocks that are nnn bytes in size and 501** are aligned to an address which is an integer multiple of 502** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 503** that when data is appended to a file, the data is appended 504** first then the size of the file is extended, never the other 505** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 506** information is written to disk in the same order as calls 507** to xWrite(). 508*/ 509#define SQLITE_IOCAP_ATOMIC 0x00000001 510#define SQLITE_IOCAP_ATOMIC512 0x00000002 511#define SQLITE_IOCAP_ATOMIC1K 0x00000004 512#define SQLITE_IOCAP_ATOMIC2K 0x00000008 513#define SQLITE_IOCAP_ATOMIC4K 0x00000010 514#define SQLITE_IOCAP_ATOMIC8K 0x00000020 515#define SQLITE_IOCAP_ATOMIC16K 0x00000040 516#define SQLITE_IOCAP_ATOMIC32K 0x00000080 517#define SQLITE_IOCAP_ATOMIC64K 0x00000100 518#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 519#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 520#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 521 522/* 523** CAPI3REF: File Locking Levels 524** 525** SQLite uses one of these integer values as the second 526** argument to calls it makes to the xLock() and xUnlock() methods 527** of an [sqlite3_io_methods] object. 528*/ 529#define SQLITE_LOCK_NONE 0 530#define SQLITE_LOCK_SHARED 1 531#define SQLITE_LOCK_RESERVED 2 532#define SQLITE_LOCK_PENDING 3 533#define SQLITE_LOCK_EXCLUSIVE 4 534 535/* 536** CAPI3REF: Synchronization Type Flags 537** 538** When SQLite invokes the xSync() method of an 539** [sqlite3_io_methods] object it uses a combination of 540** these integer values as the second argument. 541** 542** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 543** sync operation only needs to flush data to mass storage. Inode 544** information need not be flushed. If the lower four bits of the flag 545** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 546** If the lower four bits equal SQLITE_SYNC_FULL, that means 547** to use Mac OS X style fullsync instead of fsync(). 548** 549** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 550** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 551** settings. The [synchronous pragma] determines when calls to the 552** xSync VFS method occur and applies uniformly across all platforms. 553** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 554** energetic or rigorous or forceful the sync operations are and 555** only make a difference on Mac OSX for the default SQLite code. 556** (Third-party VFS implementations might also make the distinction 557** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 558** operating systems natively supported by SQLite, only Mac OSX 559** cares about the difference.) 560*/ 561#define SQLITE_SYNC_NORMAL 0x00002 562#define SQLITE_SYNC_FULL 0x00003 563#define SQLITE_SYNC_DATAONLY 0x00010 564 565/* 566** CAPI3REF: OS Interface Open File Handle 567** 568** An [sqlite3_file] object represents an open file in the 569** [sqlite3_vfs | OS interface layer]. Individual OS interface 570** implementations will 571** want to subclass this object by appending additional fields 572** for their own use. The pMethods entry is a pointer to an 573** [sqlite3_io_methods] object that defines methods for performing 574** I/O operations on the open file. 575*/ 576typedef struct sqlite3_file sqlite3_file; 577struct sqlite3_file { 578 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 579}; 580 581/* 582** CAPI3REF: OS Interface File Virtual Methods Object 583** 584** Every file opened by the [sqlite3_vfs] xOpen method populates an 585** [sqlite3_file] object (or, more commonly, a subclass of the 586** [sqlite3_file] object) with a pointer to an instance of this object. 587** This object defines the methods used to perform various operations 588** against the open file represented by the [sqlite3_file] object. 589** 590** If the xOpen method sets the sqlite3_file.pMethods element 591** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 592** may be invoked even if the xOpen reported that it failed. The 593** only way to prevent a call to xClose following a failed xOpen 594** is for the xOpen to set the sqlite3_file.pMethods element to NULL. 595** 596** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 597** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 598** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 599** flag may be ORed in to indicate that only the data of the file 600** and not its inode needs to be synced. 601** 602** The integer values to xLock() and xUnlock() are one of 603** <ul> 604** <li> [SQLITE_LOCK_NONE], 605** <li> [SQLITE_LOCK_SHARED], 606** <li> [SQLITE_LOCK_RESERVED], 607** <li> [SQLITE_LOCK_PENDING], or 608** <li> [SQLITE_LOCK_EXCLUSIVE]. 609** </ul> 610** xLock() increases the lock. xUnlock() decreases the lock. 611** The xCheckReservedLock() method checks whether any database connection, 612** either in this process or in some other process, is holding a RESERVED, 613** PENDING, or EXCLUSIVE lock on the file. It returns true 614** if such a lock exists and false otherwise. 615** 616** The xFileControl() method is a generic interface that allows custom 617** VFS implementations to directly control an open file using the 618** [sqlite3_file_control()] interface. The second "op" argument is an 619** integer opcode. The third argument is a generic pointer intended to 620** point to a structure that may contain arguments or space in which to 621** write return values. Potential uses for xFileControl() might be 622** functions to enable blocking locks with timeouts, to change the 623** locking strategy (for example to use dot-file locks), to inquire 624** about the status of a lock, or to break stale locks. The SQLite 625** core reserves all opcodes less than 100 for its own use. 626** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 627** Applications that define a custom xFileControl method should use opcodes 628** greater than 100 to avoid conflicts. 629** 630** The xSectorSize() method returns the sector size of the 631** device that underlies the file. The sector size is the 632** minimum write that can be performed without disturbing 633** other bytes in the file. The xDeviceCharacteristics() 634** method returns a bit vector describing behaviors of the 635** underlying device: 636** 637** <ul> 638** <li> [SQLITE_IOCAP_ATOMIC] 639** <li> [SQLITE_IOCAP_ATOMIC512] 640** <li> [SQLITE_IOCAP_ATOMIC1K] 641** <li> [SQLITE_IOCAP_ATOMIC2K] 642** <li> [SQLITE_IOCAP_ATOMIC4K] 643** <li> [SQLITE_IOCAP_ATOMIC8K] 644** <li> [SQLITE_IOCAP_ATOMIC16K] 645** <li> [SQLITE_IOCAP_ATOMIC32K] 646** <li> [SQLITE_IOCAP_ATOMIC64K] 647** <li> [SQLITE_IOCAP_SAFE_APPEND] 648** <li> [SQLITE_IOCAP_SEQUENTIAL] 649** </ul> 650** 651** The SQLITE_IOCAP_ATOMIC property means that all writes of 652** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 653** mean that writes of blocks that are nnn bytes in size and 654** are aligned to an address which is an integer multiple of 655** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 656** that when data is appended to a file, the data is appended 657** first then the size of the file is extended, never the other 658** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 659** information is written to disk in the same order as calls 660** to xWrite(). 661** 662** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 663** in the unread portions of the buffer with zeros. A VFS that 664** fails to zero-fill short reads might seem to work. However, 665** failure to zero-fill short reads will eventually lead to 666** database corruption. 667*/ 668typedef struct sqlite3_io_methods sqlite3_io_methods; 669struct sqlite3_io_methods { 670 int iVersion; 671 int (*xClose)(sqlite3_file*); 672 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 673 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 674 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 675 int (*xSync)(sqlite3_file*, int flags); 676 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 677 int (*xLock)(sqlite3_file*, int); 678 int (*xUnlock)(sqlite3_file*, int); 679 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 680 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 681 int (*xSectorSize)(sqlite3_file*); 682 int (*xDeviceCharacteristics)(sqlite3_file*); 683 /* Methods above are valid for version 1 */ 684 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 685 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 686 void (*xShmBarrier)(sqlite3_file*); 687 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 688 /* Methods above are valid for version 2 */ 689 /* Additional methods may be added in future releases */ 690}; 691 692/* 693** CAPI3REF: Standard File Control Opcodes 694** 695** These integer constants are opcodes for the xFileControl method 696** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 697** interface. 698** 699** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 700** opcode causes the xFileControl method to write the current state of 701** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 702** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 703** into an integer that the pArg argument points to. This capability 704** is used during testing and only needs to be supported when SQLITE_TEST 705** is defined. 706** 707** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 708** layer a hint of how large the database file will grow to be during the 709** current transaction. This hint is not guaranteed to be accurate but it 710** is often close. The underlying VFS might choose to preallocate database 711** file space based on this hint in order to help writes to the database 712** file run faster. 713** 714** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 715** extends and truncates the database file in chunks of a size specified 716** by the user. The fourth argument to [sqlite3_file_control()] should 717** point to an integer (type int) containing the new chunk-size to use 718** for the nominated database. Allocating database file space in large 719** chunks (say 1MB at a time), may reduce file-system fragmentation and 720** improve performance on some systems. 721*/ 722#define SQLITE_FCNTL_LOCKSTATE 1 723#define SQLITE_GET_LOCKPROXYFILE 2 724#define SQLITE_SET_LOCKPROXYFILE 3 725#define SQLITE_LAST_ERRNO 4 726#define SQLITE_FCNTL_SIZE_HINT 5 727#define SQLITE_FCNTL_CHUNK_SIZE 6 728#define SQLITE_FCNTL_FILE_POINTER 7 729 730 731/* 732** CAPI3REF: Mutex Handle 733** 734** The mutex module within SQLite defines [sqlite3_mutex] to be an 735** abstract type for a mutex object. The SQLite core never looks 736** at the internal representation of an [sqlite3_mutex]. It only 737** deals with pointers to the [sqlite3_mutex] object. 738** 739** Mutexes are created using [sqlite3_mutex_alloc()]. 740*/ 741typedef struct sqlite3_mutex sqlite3_mutex; 742 743/* 744** CAPI3REF: OS Interface Object 745** 746** An instance of the sqlite3_vfs object defines the interface between 747** the SQLite core and the underlying operating system. The "vfs" 748** in the name of the object stands for "virtual file system". 749** 750** The value of the iVersion field is initially 1 but may be larger in 751** future versions of SQLite. Additional fields may be appended to this 752** object when the iVersion value is increased. Note that the structure 753** of the sqlite3_vfs object changes in the transaction between 754** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 755** modified. 756** 757** The szOsFile field is the size of the subclassed [sqlite3_file] 758** structure used by this VFS. mxPathname is the maximum length of 759** a pathname in this VFS. 760** 761** Registered sqlite3_vfs objects are kept on a linked list formed by 762** the pNext pointer. The [sqlite3_vfs_register()] 763** and [sqlite3_vfs_unregister()] interfaces manage this list 764** in a thread-safe way. The [sqlite3_vfs_find()] interface 765** searches the list. Neither the application code nor the VFS 766** implementation should use the pNext pointer. 767** 768** The pNext field is the only field in the sqlite3_vfs 769** structure that SQLite will ever modify. SQLite will only access 770** or modify this field while holding a particular static mutex. 771** The application should never modify anything within the sqlite3_vfs 772** object once the object has been registered. 773** 774** The zName field holds the name of the VFS module. The name must 775** be unique across all VFS modules. 776** 777** ^SQLite guarantees that the zFilename parameter to xOpen 778** is either a NULL pointer or string obtained 779** from xFullPathname() with an optional suffix added. 780** ^If a suffix is added to the zFilename parameter, it will 781** consist of a single "-" character followed by no more than 782** 10 alphanumeric and/or "-" characters. 783** ^SQLite further guarantees that 784** the string will be valid and unchanged until xClose() is 785** called. Because of the previous sentence, 786** the [sqlite3_file] can safely store a pointer to the 787** filename if it needs to remember the filename for some reason. 788** If the zFilename parameter to xOpen is a NULL pointer then xOpen 789** must invent its own temporary name for the file. ^Whenever the 790** xFilename parameter is NULL it will also be the case that the 791** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 792** 793** The flags argument to xOpen() includes all bits set in 794** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 795** or [sqlite3_open16()] is used, then flags includes at least 796** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 797** If xOpen() opens a file read-only then it sets *pOutFlags to 798** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 799** 800** ^(SQLite will also add one of the following flags to the xOpen() 801** call, depending on the object being opened: 802** 803** <ul> 804** <li> [SQLITE_OPEN_MAIN_DB] 805** <li> [SQLITE_OPEN_MAIN_JOURNAL] 806** <li> [SQLITE_OPEN_TEMP_DB] 807** <li> [SQLITE_OPEN_TEMP_JOURNAL] 808** <li> [SQLITE_OPEN_TRANSIENT_DB] 809** <li> [SQLITE_OPEN_SUBJOURNAL] 810** <li> [SQLITE_OPEN_MASTER_JOURNAL] 811** <li> [SQLITE_OPEN_WAL] 812** </ul>)^ 813** 814** The file I/O implementation can use the object type flags to 815** change the way it deals with files. For example, an application 816** that does not care about crash recovery or rollback might make 817** the open of a journal file a no-op. Writes to this journal would 818** also be no-ops, and any attempt to read the journal would return 819** SQLITE_IOERR. Or the implementation might recognize that a database 820** file will be doing page-aligned sector reads and writes in a random 821** order and set up its I/O subsystem accordingly. 822** 823** SQLite might also add one of the following flags to the xOpen method: 824** 825** <ul> 826** <li> [SQLITE_OPEN_DELETEONCLOSE] 827** <li> [SQLITE_OPEN_EXCLUSIVE] 828** </ul> 829** 830** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 831** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 832** will be set for TEMP databases and their journals, transient 833** databases, and subjournals. 834** 835** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 836** with the [SQLITE_OPEN_CREATE] flag, which are both directly 837** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 838** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 839** SQLITE_OPEN_CREATE, is used to indicate that file should always 840** be created, and that it is an error if it already exists. 841** It is <i>not</i> used to indicate the file should be opened 842** for exclusive access. 843** 844** ^At least szOsFile bytes of memory are allocated by SQLite 845** to hold the [sqlite3_file] structure passed as the third 846** argument to xOpen. The xOpen method does not have to 847** allocate the structure; it should just fill it in. Note that 848** the xOpen method must set the sqlite3_file.pMethods to either 849** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 850** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 851** element will be valid after xOpen returns regardless of the success 852** or failure of the xOpen call. 853** 854** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 855** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 856** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 857** to test whether a file is at least readable. The file can be a 858** directory. 859** 860** ^SQLite will always allocate at least mxPathname+1 bytes for the 861** output buffer xFullPathname. The exact size of the output buffer 862** is also passed as a parameter to both methods. If the output buffer 863** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 864** handled as a fatal error by SQLite, vfs implementations should endeavor 865** to prevent this by setting mxPathname to a sufficiently large value. 866** 867** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 868** interfaces are not strictly a part of the filesystem, but they are 869** included in the VFS structure for completeness. 870** The xRandomness() function attempts to return nBytes bytes 871** of good-quality randomness into zOut. The return value is 872** the actual number of bytes of randomness obtained. 873** The xSleep() method causes the calling thread to sleep for at 874** least the number of microseconds given. ^The xCurrentTime() 875** method returns a Julian Day Number for the current date and time as 876** a floating point value. 877** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 878** Day Number multipled by 86400000 (the number of milliseconds in 879** a 24-hour day). 880** ^SQLite will use the xCurrentTimeInt64() method to get the current 881** date and time if that method is available (if iVersion is 2 or 882** greater and the function pointer is not NULL) and will fall back 883** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 884*/ 885typedef struct sqlite3_vfs sqlite3_vfs; 886struct sqlite3_vfs { 887 int iVersion; /* Structure version number (currently 2) */ 888 int szOsFile; /* Size of subclassed sqlite3_file */ 889 int mxPathname; /* Maximum file pathname length */ 890 sqlite3_vfs *pNext; /* Next registered VFS */ 891 const char *zName; /* Name of this virtual file system */ 892 void *pAppData; /* Pointer to application-specific data */ 893 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 894 int flags, int *pOutFlags); 895 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 896 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 897 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 898 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 899 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 900 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 901 void (*xDlClose)(sqlite3_vfs*, void*); 902 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 903 int (*xSleep)(sqlite3_vfs*, int microseconds); 904 int (*xCurrentTime)(sqlite3_vfs*, double*); 905 int (*xGetLastError)(sqlite3_vfs*, int, char *); 906 /* 907 ** The methods above are in version 1 of the sqlite_vfs object 908 ** definition. Those that follow are added in version 2 or later 909 */ 910 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 911 /* 912 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 913 ** New fields may be appended in figure versions. The iVersion 914 ** value will increment whenever this happens. 915 */ 916}; 917 918/* 919** CAPI3REF: Flags for the xAccess VFS method 920** 921** These integer constants can be used as the third parameter to 922** the xAccess method of an [sqlite3_vfs] object. They determine 923** what kind of permissions the xAccess method is looking for. 924** With SQLITE_ACCESS_EXISTS, the xAccess method 925** simply checks whether the file exists. 926** With SQLITE_ACCESS_READWRITE, the xAccess method 927** checks whether the named directory is both readable and writable 928** (in other words, if files can be added, removed, and renamed within 929** the directory). 930** The SQLITE_ACCESS_READWRITE constant is currently used only by the 931** [temp_store_directory pragma], though this could change in a future 932** release of SQLite. 933** With SQLITE_ACCESS_READ, the xAccess method 934** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 935** currently unused, though it might be used in a future release of 936** SQLite. 937*/ 938#define SQLITE_ACCESS_EXISTS 0 939#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 940#define SQLITE_ACCESS_READ 2 /* Unused */ 941 942/* 943** CAPI3REF: Flags for the xShmLock VFS method 944** 945** These integer constants define the various locking operations 946** allowed by the xShmLock method of [sqlite3_io_methods]. The 947** following are the only legal combinations of flags to the 948** xShmLock method: 949** 950** <ul> 951** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 952** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 953** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 954** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 955** </ul> 956** 957** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 958** was given no the corresponding lock. 959** 960** The xShmLock method can transition between unlocked and SHARED or 961** between unlocked and EXCLUSIVE. It cannot transition between SHARED 962** and EXCLUSIVE. 963*/ 964#define SQLITE_SHM_UNLOCK 1 965#define SQLITE_SHM_LOCK 2 966#define SQLITE_SHM_SHARED 4 967#define SQLITE_SHM_EXCLUSIVE 8 968 969/* 970** CAPI3REF: Maximum xShmLock index 971** 972** The xShmLock method on [sqlite3_io_methods] may use values 973** between 0 and this upper bound as its "offset" argument. 974** The SQLite core will never attempt to acquire or release a 975** lock outside of this range 976*/ 977#define SQLITE_SHM_NLOCK 8 978 979 980/* 981** CAPI3REF: Initialize The SQLite Library 982** 983** ^The sqlite3_initialize() routine initializes the 984** SQLite library. ^The sqlite3_shutdown() routine 985** deallocates any resources that were allocated by sqlite3_initialize(). 986** These routines are designed to aid in process initialization and 987** shutdown on embedded systems. Workstation applications using 988** SQLite normally do not need to invoke either of these routines. 989** 990** A call to sqlite3_initialize() is an "effective" call if it is 991** the first time sqlite3_initialize() is invoked during the lifetime of 992** the process, or if it is the first time sqlite3_initialize() is invoked 993** following a call to sqlite3_shutdown(). ^(Only an effective call 994** of sqlite3_initialize() does any initialization. All other calls 995** are harmless no-ops.)^ 996** 997** A call to sqlite3_shutdown() is an "effective" call if it is the first 998** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 999** an effective call to sqlite3_shutdown() does any deinitialization. 1000** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1001** 1002** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1003** is not. The sqlite3_shutdown() interface must only be called from a 1004** single thread. All open [database connections] must be closed and all 1005** other SQLite resources must be deallocated prior to invoking 1006** sqlite3_shutdown(). 1007** 1008** Among other things, ^sqlite3_initialize() will invoke 1009** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1010** will invoke sqlite3_os_end(). 1011** 1012** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1013** ^If for some reason, sqlite3_initialize() is unable to initialize 1014** the library (perhaps it is unable to allocate a needed resource such 1015** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1016** 1017** ^The sqlite3_initialize() routine is called internally by many other 1018** SQLite interfaces so that an application usually does not need to 1019** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1020** calls sqlite3_initialize() so the SQLite library will be automatically 1021** initialized when [sqlite3_open()] is called if it has not be initialized 1022** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1023** compile-time option, then the automatic calls to sqlite3_initialize() 1024** are omitted and the application must call sqlite3_initialize() directly 1025** prior to using any other SQLite interface. For maximum portability, 1026** it is recommended that applications always invoke sqlite3_initialize() 1027** directly prior to using any other SQLite interface. Future releases 1028** of SQLite may require this. In other words, the behavior exhibited 1029** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1030** default behavior in some future release of SQLite. 1031** 1032** The sqlite3_os_init() routine does operating-system specific 1033** initialization of the SQLite library. The sqlite3_os_end() 1034** routine undoes the effect of sqlite3_os_init(). Typical tasks 1035** performed by these routines include allocation or deallocation 1036** of static resources, initialization of global variables, 1037** setting up a default [sqlite3_vfs] module, or setting up 1038** a default configuration using [sqlite3_config()]. 1039** 1040** The application should never invoke either sqlite3_os_init() 1041** or sqlite3_os_end() directly. The application should only invoke 1042** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1043** interface is called automatically by sqlite3_initialize() and 1044** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1045** implementations for sqlite3_os_init() and sqlite3_os_end() 1046** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1047** When [custom builds | built for other platforms] 1048** (using the [SQLITE_OS_OTHER=1] compile-time 1049** option) the application must supply a suitable implementation for 1050** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1051** implementation of sqlite3_os_init() or sqlite3_os_end() 1052** must return [SQLITE_OK] on success and some other [error code] upon 1053** failure. 1054*/ 1055SQLITE_API int sqlite3_initialize(void); 1056SQLITE_API int sqlite3_shutdown(void); 1057SQLITE_API int sqlite3_os_init(void); 1058SQLITE_API int sqlite3_os_end(void); 1059 1060/* 1061** CAPI3REF: Configuring The SQLite Library 1062** 1063** The sqlite3_config() interface is used to make global configuration 1064** changes to SQLite in order to tune SQLite to the specific needs of 1065** the application. The default configuration is recommended for most 1066** applications and so this routine is usually not necessary. It is 1067** provided to support rare applications with unusual needs. 1068** 1069** The sqlite3_config() interface is not threadsafe. The application 1070** must insure that no other SQLite interfaces are invoked by other 1071** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1072** may only be invoked prior to library initialization using 1073** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1074** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1075** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1076** Note, however, that ^sqlite3_config() can be called as part of the 1077** implementation of an application-defined [sqlite3_os_init()]. 1078** 1079** The first argument to sqlite3_config() is an integer 1080** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 1081** what property of SQLite is to be configured. Subsequent arguments 1082** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 1083** in the first argument. 1084** 1085** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1086** ^If the option is unknown or SQLite is unable to set the option 1087** then this routine returns a non-zero [error code]. 1088*/ 1089SQLITE_API int sqlite3_config(int, ...); 1090 1091/* 1092** CAPI3REF: Configure database connections 1093** 1094** The sqlite3_db_config() interface is used to make configuration 1095** changes to a [database connection]. The interface is similar to 1096** [sqlite3_config()] except that the changes apply to a single 1097** [database connection] (specified in the first argument). The 1098** sqlite3_db_config() interface should only be used immediately after 1099** the database connection is created using [sqlite3_open()], 1100** [sqlite3_open16()], or [sqlite3_open_v2()]. 1101** 1102** The second argument to sqlite3_db_config(D,V,...) is the 1103** configuration verb - an integer code that indicates what 1104** aspect of the [database connection] is being configured. 1105** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 1106** New verbs are likely to be added in future releases of SQLite. 1107** Additional arguments depend on the verb. 1108** 1109** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1110** the call is considered successful. 1111*/ 1112SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...); 1113 1114/* 1115** CAPI3REF: Memory Allocation Routines 1116** 1117** An instance of this object defines the interface between SQLite 1118** and low-level memory allocation routines. 1119** 1120** This object is used in only one place in the SQLite interface. 1121** A pointer to an instance of this object is the argument to 1122** [sqlite3_config()] when the configuration option is 1123** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1124** By creating an instance of this object 1125** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1126** during configuration, an application can specify an alternative 1127** memory allocation subsystem for SQLite to use for all of its 1128** dynamic memory needs. 1129** 1130** Note that SQLite comes with several [built-in memory allocators] 1131** that are perfectly adequate for the overwhelming majority of applications 1132** and that this object is only useful to a tiny minority of applications 1133** with specialized memory allocation requirements. This object is 1134** also used during testing of SQLite in order to specify an alternative 1135** memory allocator that simulates memory out-of-memory conditions in 1136** order to verify that SQLite recovers gracefully from such 1137** conditions. 1138** 1139** The xMalloc and xFree methods must work like the 1140** malloc() and free() functions from the standard C library. 1141** The xRealloc method must work like realloc() from the standard C library 1142** with the exception that if the second argument to xRealloc is zero, 1143** xRealloc must be a no-op - it must not perform any allocation or 1144** deallocation. ^SQLite guarantees that the second argument to 1145** xRealloc is always a value returned by a prior call to xRoundup. 1146** And so in cases where xRoundup always returns a positive number, 1147** xRealloc can perform exactly as the standard library realloc() and 1148** still be in compliance with this specification. 1149** 1150** xSize should return the allocated size of a memory allocation 1151** previously obtained from xMalloc or xRealloc. The allocated size 1152** is always at least as big as the requested size but may be larger. 1153** 1154** The xRoundup method returns what would be the allocated size of 1155** a memory allocation given a particular requested size. Most memory 1156** allocators round up memory allocations at least to the next multiple 1157** of 8. Some allocators round up to a larger multiple or to a power of 2. 1158** Every memory allocation request coming in through [sqlite3_malloc()] 1159** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1160** that causes the corresponding memory allocation to fail. 1161** 1162** The xInit method initializes the memory allocator. (For example, 1163** it might allocate any require mutexes or initialize internal data 1164** structures. The xShutdown method is invoked (indirectly) by 1165** [sqlite3_shutdown()] and should deallocate any resources acquired 1166** by xInit. The pAppData pointer is used as the only parameter to 1167** xInit and xShutdown. 1168** 1169** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1170** the xInit method, so the xInit method need not be threadsafe. The 1171** xShutdown method is only called from [sqlite3_shutdown()] so it does 1172** not need to be threadsafe either. For all other methods, SQLite 1173** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1174** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1175** it is by default) and so the methods are automatically serialized. 1176** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1177** methods must be threadsafe or else make their own arrangements for 1178** serialization. 1179** 1180** SQLite will never invoke xInit() more than once without an intervening 1181** call to xShutdown(). 1182*/ 1183typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1184struct sqlite3_mem_methods { 1185 void *(*xMalloc)(int); /* Memory allocation function */ 1186 void (*xFree)(void*); /* Free a prior allocation */ 1187 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1188 int (*xSize)(void*); /* Return the size of an allocation */ 1189 int (*xRoundup)(int); /* Round up request size to allocation size */ 1190 int (*xInit)(void*); /* Initialize the memory allocator */ 1191 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1192 void *pAppData; /* Argument to xInit() and xShutdown() */ 1193}; 1194 1195/* 1196** CAPI3REF: Configuration Options 1197** 1198** These constants are the available integer configuration options that 1199** can be passed as the first argument to the [sqlite3_config()] interface. 1200** 1201** New configuration options may be added in future releases of SQLite. 1202** Existing configuration options might be discontinued. Applications 1203** should check the return code from [sqlite3_config()] to make sure that 1204** the call worked. The [sqlite3_config()] interface will return a 1205** non-zero [error code] if a discontinued or unsupported configuration option 1206** is invoked. 1207** 1208** <dl> 1209** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1210** <dd>There are no arguments to this option. ^This option sets the 1211** [threading mode] to Single-thread. In other words, it disables 1212** all mutexing and puts SQLite into a mode where it can only be used 1213** by a single thread. ^If SQLite is compiled with 1214** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1215** it is not possible to change the [threading mode] from its default 1216** value of Single-thread and so [sqlite3_config()] will return 1217** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1218** configuration option.</dd> 1219** 1220** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1221** <dd>There are no arguments to this option. ^This option sets the 1222** [threading mode] to Multi-thread. In other words, it disables 1223** mutexing on [database connection] and [prepared statement] objects. 1224** The application is responsible for serializing access to 1225** [database connections] and [prepared statements]. But other mutexes 1226** are enabled so that SQLite will be safe to use in a multi-threaded 1227** environment as long as no two threads attempt to use the same 1228** [database connection] at the same time. ^If SQLite is compiled with 1229** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1230** it is not possible to set the Multi-thread [threading mode] and 1231** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1232** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1233** 1234** <dt>SQLITE_CONFIG_SERIALIZED</dt> 1235** <dd>There are no arguments to this option. ^This option sets the 1236** [threading mode] to Serialized. In other words, this option enables 1237** all mutexes including the recursive 1238** mutexes on [database connection] and [prepared statement] objects. 1239** In this mode (which is the default when SQLite is compiled with 1240** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1241** to [database connections] and [prepared statements] so that the 1242** application is free to use the same [database connection] or the 1243** same [prepared statement] in different threads at the same time. 1244** ^If SQLite is compiled with 1245** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1246** it is not possible to set the Serialized [threading mode] and 1247** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1248** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1249** 1250** <dt>SQLITE_CONFIG_MALLOC</dt> 1251** <dd> ^(This option takes a single argument which is a pointer to an 1252** instance of the [sqlite3_mem_methods] structure. The argument specifies 1253** alternative low-level memory allocation routines to be used in place of 1254** the memory allocation routines built into SQLite.)^ ^SQLite makes 1255** its own private copy of the content of the [sqlite3_mem_methods] structure 1256** before the [sqlite3_config()] call returns.</dd> 1257** 1258** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1259** <dd> ^(This option takes a single argument which is a pointer to an 1260** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1261** structure is filled with the currently defined memory allocation routines.)^ 1262** This option can be used to overload the default memory allocation 1263** routines with a wrapper that simulations memory allocation failure or 1264** tracks memory usage, for example. </dd> 1265** 1266** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1267** <dd> ^This option takes single argument of type int, interpreted as a 1268** boolean, which enables or disables the collection of memory allocation 1269** statistics. ^(When memory allocation statistics are disabled, the 1270** following SQLite interfaces become non-operational: 1271** <ul> 1272** <li> [sqlite3_memory_used()] 1273** <li> [sqlite3_memory_highwater()] 1274** <li> [sqlite3_soft_heap_limit64()] 1275** <li> [sqlite3_status()] 1276** </ul>)^ 1277** ^Memory allocation statistics are enabled by default unless SQLite is 1278** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1279** allocation statistics are disabled by default. 1280** </dd> 1281** 1282** <dt>SQLITE_CONFIG_SCRATCH</dt> 1283** <dd> ^This option specifies a static memory buffer that SQLite can use for 1284** scratch memory. There are three arguments: A pointer an 8-byte 1285** aligned memory buffer from which the scrach allocations will be 1286** drawn, the size of each scratch allocation (sz), 1287** and the maximum number of scratch allocations (N). The sz 1288** argument must be a multiple of 16. 1289** The first argument must be a pointer to an 8-byte aligned buffer 1290** of at least sz*N bytes of memory. 1291** ^SQLite will use no more than two scratch buffers per thread. So 1292** N should be set to twice the expected maximum number of threads. 1293** ^SQLite will never require a scratch buffer that is more than 6 1294** times the database page size. ^If SQLite needs needs additional 1295** scratch memory beyond what is provided by this configuration option, then 1296** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1297** 1298** <dt>SQLITE_CONFIG_PAGECACHE</dt> 1299** <dd> ^This option specifies a static memory buffer that SQLite can use for 1300** the database page cache with the default page cache implemenation. 1301** This configuration should not be used if an application-define page 1302** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1303** There are three arguments to this option: A pointer to 8-byte aligned 1304** memory, the size of each page buffer (sz), and the number of pages (N). 1305** The sz argument should be the size of the largest database page 1306** (a power of two between 512 and 32768) plus a little extra for each 1307** page header. ^The page header size is 20 to 40 bytes depending on 1308** the host architecture. ^It is harmless, apart from the wasted memory, 1309** to make sz a little too large. The first 1310** argument should point to an allocation of at least sz*N bytes of memory. 1311** ^SQLite will use the memory provided by the first argument to satisfy its 1312** memory needs for the first N pages that it adds to cache. ^If additional 1313** page cache memory is needed beyond what is provided by this option, then 1314** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1315** The pointer in the first argument must 1316** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1317** will be undefined.</dd> 1318** 1319** <dt>SQLITE_CONFIG_HEAP</dt> 1320** <dd> ^This option specifies a static memory buffer that SQLite will use 1321** for all of its dynamic memory allocation needs beyond those provided 1322** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1323** There are three arguments: An 8-byte aligned pointer to the memory, 1324** the number of bytes in the memory buffer, and the minimum allocation size. 1325** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1326** to using its default memory allocator (the system malloc() implementation), 1327** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1328** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1329** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1330** allocator is engaged to handle all of SQLites memory allocation needs. 1331** The first pointer (the memory pointer) must be aligned to an 8-byte 1332** boundary or subsequent behavior of SQLite will be undefined.</dd> 1333** 1334** <dt>SQLITE_CONFIG_MUTEX</dt> 1335** <dd> ^(This option takes a single argument which is a pointer to an 1336** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1337** alternative low-level mutex routines to be used in place 1338** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1339** content of the [sqlite3_mutex_methods] structure before the call to 1340** [sqlite3_config()] returns. ^If SQLite is compiled with 1341** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1342** the entire mutexing subsystem is omitted from the build and hence calls to 1343** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1344** return [SQLITE_ERROR].</dd> 1345** 1346** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1347** <dd> ^(This option takes a single argument which is a pointer to an 1348** instance of the [sqlite3_mutex_methods] structure. The 1349** [sqlite3_mutex_methods] 1350** structure is filled with the currently defined mutex routines.)^ 1351** This option can be used to overload the default mutex allocation 1352** routines with a wrapper used to track mutex usage for performance 1353** profiling or testing, for example. ^If SQLite is compiled with 1354** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1355** the entire mutexing subsystem is omitted from the build and hence calls to 1356** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1357** return [SQLITE_ERROR].</dd> 1358** 1359** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1360** <dd> ^(This option takes two arguments that determine the default 1361** memory allocation for the lookaside memory allocator on each 1362** [database connection]. The first argument is the 1363** size of each lookaside buffer slot and the second is the number of 1364** slots allocated to each database connection.)^ ^(This option sets the 1365** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1366** verb to [sqlite3_db_config()] can be used to change the lookaside 1367** configuration on individual connections.)^ </dd> 1368** 1369** <dt>SQLITE_CONFIG_PCACHE</dt> 1370** <dd> ^(This option takes a single argument which is a pointer to 1371** an [sqlite3_pcache_methods] object. This object specifies the interface 1372** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1373** object and uses it for page cache memory allocations.</dd> 1374** 1375** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1376** <dd> ^(This option takes a single argument which is a pointer to an 1377** [sqlite3_pcache_methods] object. SQLite copies of the current 1378** page cache implementation into that object.)^ </dd> 1379** 1380** <dt>SQLITE_CONFIG_LOG</dt> 1381** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1382** function with a call signature of void(*)(void*,int,const char*), 1383** and a pointer to void. ^If the function pointer is not NULL, it is 1384** invoked by [sqlite3_log()] to process each logging event. ^If the 1385** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1386** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1387** passed through as the first parameter to the application-defined logger 1388** function whenever that function is invoked. ^The second parameter to 1389** the logger function is a copy of the first parameter to the corresponding 1390** [sqlite3_log()] call and is intended to be a [result code] or an 1391** [extended result code]. ^The third parameter passed to the logger is 1392** log message after formatting via [sqlite3_snprintf()]. 1393** The SQLite logging interface is not reentrant; the logger function 1394** supplied by the application must not invoke any SQLite interface. 1395** In a multi-threaded application, the application-defined logger 1396** function must be threadsafe. </dd> 1397** 1398** </dl> 1399*/ 1400#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1401#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1402#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1403#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1404#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1405#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1406#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1407#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1408#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1409#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1410#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1411/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1412#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1413#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1414#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1415#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1416 1417/* 1418** CAPI3REF: Database Connection Configuration Options 1419** 1420** These constants are the available integer configuration options that 1421** can be passed as the second argument to the [sqlite3_db_config()] interface. 1422** 1423** New configuration options may be added in future releases of SQLite. 1424** Existing configuration options might be discontinued. Applications 1425** should check the return code from [sqlite3_db_config()] to make sure that 1426** the call worked. ^The [sqlite3_db_config()] interface will return a 1427** non-zero [error code] if a discontinued or unsupported configuration option 1428** is invoked. 1429** 1430** <dl> 1431** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1432** <dd> ^This option takes three additional arguments that determine the 1433** [lookaside memory allocator] configuration for the [database connection]. 1434** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1435** pointer to an memory buffer to use for lookaside memory. 1436** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1437** may be NULL in which case SQLite will allocate the 1438** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1439** size of each lookaside buffer slot. ^The third argument is the number of 1440** slots. The size of the buffer in the first argument must be greater than 1441** or equal to the product of the second and third arguments. The buffer 1442** must be aligned to an 8-byte boundary. ^If the second argument to 1443** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1444** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1445** configuration for a database connection can only be changed when that 1446** connection is not currently using lookaside memory, or in other words 1447** when the "current value" returned by 1448** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1449** Any attempt to change the lookaside memory configuration when lookaside 1450** memory is in use leaves the configuration unchanged and returns 1451** [SQLITE_BUSY].)^</dd> 1452** 1453** </dl> 1454*/ 1455#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1456 1457 1458/* 1459** CAPI3REF: Enable Or Disable Extended Result Codes 1460** 1461** ^The sqlite3_extended_result_codes() routine enables or disables the 1462** [extended result codes] feature of SQLite. ^The extended result 1463** codes are disabled by default for historical compatibility. 1464*/ 1465SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); 1466 1467/* 1468** CAPI3REF: Last Insert Rowid 1469** 1470** ^Each entry in an SQLite table has a unique 64-bit signed 1471** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1472** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1473** names are not also used by explicitly declared columns. ^If 1474** the table has a column of type [INTEGER PRIMARY KEY] then that column 1475** is another alias for the rowid. 1476** 1477** ^This routine returns the [rowid] of the most recent 1478** successful [INSERT] into the database from the [database connection] 1479** in the first argument. ^If no successful [INSERT]s 1480** have ever occurred on that database connection, zero is returned. 1481** 1482** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1483** row is returned by this routine as long as the trigger is running. 1484** But once the trigger terminates, the value returned by this routine 1485** reverts to the last value inserted before the trigger fired.)^ 1486** 1487** ^An [INSERT] that fails due to a constraint violation is not a 1488** successful [INSERT] and does not change the value returned by this 1489** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1490** and INSERT OR ABORT make no changes to the return value of this 1491** routine when their insertion fails. ^(When INSERT OR REPLACE 1492** encounters a constraint violation, it does not fail. The 1493** INSERT continues to completion after deleting rows that caused 1494** the constraint problem so INSERT OR REPLACE will always change 1495** the return value of this interface.)^ 1496** 1497** ^For the purposes of this routine, an [INSERT] is considered to 1498** be successful even if it is subsequently rolled back. 1499** 1500** This function is accessible to SQL statements via the 1501** [last_insert_rowid() SQL function]. 1502** 1503** If a separate thread performs a new [INSERT] on the same 1504** database connection while the [sqlite3_last_insert_rowid()] 1505** function is running and thus changes the last insert [rowid], 1506** then the value returned by [sqlite3_last_insert_rowid()] is 1507** unpredictable and might not equal either the old or the new 1508** last insert [rowid]. 1509*/ 1510SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1511 1512/* 1513** CAPI3REF: Count The Number Of Rows Modified 1514** 1515** ^This function returns the number of database rows that were changed 1516** or inserted or deleted by the most recently completed SQL statement 1517** on the [database connection] specified by the first parameter. 1518** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1519** or [DELETE] statement are counted. Auxiliary changes caused by 1520** triggers or [foreign key actions] are not counted.)^ Use the 1521** [sqlite3_total_changes()] function to find the total number of changes 1522** including changes caused by triggers and foreign key actions. 1523** 1524** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1525** are not counted. Only real table changes are counted. 1526** 1527** ^(A "row change" is a change to a single row of a single table 1528** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1529** are changed as side effects of [REPLACE] constraint resolution, 1530** rollback, ABORT processing, [DROP TABLE], or by any other 1531** mechanisms do not count as direct row changes.)^ 1532** 1533** A "trigger context" is a scope of execution that begins and 1534** ends with the script of a [CREATE TRIGGER | trigger]. 1535** Most SQL statements are 1536** evaluated outside of any trigger. This is the "top level" 1537** trigger context. If a trigger fires from the top level, a 1538** new trigger context is entered for the duration of that one 1539** trigger. Subtriggers create subcontexts for their duration. 1540** 1541** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1542** not create a new trigger context. 1543** 1544** ^This function returns the number of direct row changes in the 1545** most recent INSERT, UPDATE, or DELETE statement within the same 1546** trigger context. 1547** 1548** ^Thus, when called from the top level, this function returns the 1549** number of changes in the most recent INSERT, UPDATE, or DELETE 1550** that also occurred at the top level. ^(Within the body of a trigger, 1551** the sqlite3_changes() interface can be called to find the number of 1552** changes in the most recently completed INSERT, UPDATE, or DELETE 1553** statement within the body of the same trigger. 1554** However, the number returned does not include changes 1555** caused by subtriggers since those have their own context.)^ 1556** 1557** See also the [sqlite3_total_changes()] interface, the 1558** [count_changes pragma], and the [changes() SQL function]. 1559** 1560** If a separate thread makes changes on the same database connection 1561** while [sqlite3_changes()] is running then the value returned 1562** is unpredictable and not meaningful. 1563*/ 1564SQLITE_API int sqlite3_changes(sqlite3*); 1565 1566/* 1567** CAPI3REF: Total Number Of Rows Modified 1568** 1569** ^This function returns the number of row changes caused by [INSERT], 1570** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1571** ^(The count returned by sqlite3_total_changes() includes all changes 1572** from all [CREATE TRIGGER | trigger] contexts and changes made by 1573** [foreign key actions]. However, 1574** the count does not include changes used to implement [REPLACE] constraints, 1575** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1576** count does not include rows of views that fire an [INSTEAD OF trigger], 1577** though if the INSTEAD OF trigger makes changes of its own, those changes 1578** are counted.)^ 1579** ^The sqlite3_total_changes() function counts the changes as soon as 1580** the statement that makes them is completed (when the statement handle 1581** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1582** 1583** See also the [sqlite3_changes()] interface, the 1584** [count_changes pragma], and the [total_changes() SQL function]. 1585** 1586** If a separate thread makes changes on the same database connection 1587** while [sqlite3_total_changes()] is running then the value 1588** returned is unpredictable and not meaningful. 1589*/ 1590SQLITE_API int sqlite3_total_changes(sqlite3*); 1591 1592/* 1593** CAPI3REF: Interrupt A Long-Running Query 1594** 1595** ^This function causes any pending database operation to abort and 1596** return at its earliest opportunity. This routine is typically 1597** called in response to a user action such as pressing "Cancel" 1598** or Ctrl-C where the user wants a long query operation to halt 1599** immediately. 1600** 1601** ^It is safe to call this routine from a thread different from the 1602** thread that is currently running the database operation. But it 1603** is not safe to call this routine with a [database connection] that 1604** is closed or might close before sqlite3_interrupt() returns. 1605** 1606** ^If an SQL operation is very nearly finished at the time when 1607** sqlite3_interrupt() is called, then it might not have an opportunity 1608** to be interrupted and might continue to completion. 1609** 1610** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1611** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1612** that is inside an explicit transaction, then the entire transaction 1613** will be rolled back automatically. 1614** 1615** ^The sqlite3_interrupt(D) call is in effect until all currently running 1616** SQL statements on [database connection] D complete. ^Any new SQL statements 1617** that are started after the sqlite3_interrupt() call and before the 1618** running statements reaches zero are interrupted as if they had been 1619** running prior to the sqlite3_interrupt() call. ^New SQL statements 1620** that are started after the running statement count reaches zero are 1621** not effected by the sqlite3_interrupt(). 1622** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1623** SQL statements is a no-op and has no effect on SQL statements 1624** that are started after the sqlite3_interrupt() call returns. 1625** 1626** If the database connection closes while [sqlite3_interrupt()] 1627** is running then bad things will likely happen. 1628*/ 1629SQLITE_API void sqlite3_interrupt(sqlite3*); 1630 1631/* 1632** CAPI3REF: Determine If An SQL Statement Is Complete 1633** 1634** These routines are useful during command-line input to determine if the 1635** currently entered text seems to form a complete SQL statement or 1636** if additional input is needed before sending the text into 1637** SQLite for parsing. ^These routines return 1 if the input string 1638** appears to be a complete SQL statement. ^A statement is judged to be 1639** complete if it ends with a semicolon token and is not a prefix of a 1640** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1641** string literals or quoted identifier names or comments are not 1642** independent tokens (they are part of the token in which they are 1643** embedded) and thus do not count as a statement terminator. ^Whitespace 1644** and comments that follow the final semicolon are ignored. 1645** 1646** ^These routines return 0 if the statement is incomplete. ^If a 1647** memory allocation fails, then SQLITE_NOMEM is returned. 1648** 1649** ^These routines do not parse the SQL statements thus 1650** will not detect syntactically incorrect SQL. 1651** 1652** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1653** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1654** automatically by sqlite3_complete16(). If that initialization fails, 1655** then the return value from sqlite3_complete16() will be non-zero 1656** regardless of whether or not the input SQL is complete.)^ 1657** 1658** The input to [sqlite3_complete()] must be a zero-terminated 1659** UTF-8 string. 1660** 1661** The input to [sqlite3_complete16()] must be a zero-terminated 1662** UTF-16 string in native byte order. 1663*/ 1664SQLITE_API int sqlite3_complete(const char *sql); 1665SQLITE_API int sqlite3_complete16(const void *sql); 1666 1667/* 1668** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1669** 1670** ^This routine sets a callback function that might be invoked whenever 1671** an attempt is made to open a database table that another thread 1672** or process has locked. 1673** 1674** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1675** is returned immediately upon encountering the lock. ^If the busy callback 1676** is not NULL, then the callback might be invoked with two arguments. 1677** 1678** ^The first argument to the busy handler is a copy of the void* pointer which 1679** is the third argument to sqlite3_busy_handler(). ^The second argument to 1680** the busy handler callback is the number of times that the busy handler has 1681** been invoked for this locking event. ^If the 1682** busy callback returns 0, then no additional attempts are made to 1683** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1684** ^If the callback returns non-zero, then another attempt 1685** is made to open the database for reading and the cycle repeats. 1686** 1687** The presence of a busy handler does not guarantee that it will be invoked 1688** when there is lock contention. ^If SQLite determines that invoking the busy 1689** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1690** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1691** Consider a scenario where one process is holding a read lock that 1692** it is trying to promote to a reserved lock and 1693** a second process is holding a reserved lock that it is trying 1694** to promote to an exclusive lock. The first process cannot proceed 1695** because it is blocked by the second and the second process cannot 1696** proceed because it is blocked by the first. If both processes 1697** invoke the busy handlers, neither will make any progress. Therefore, 1698** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1699** will induce the first process to release its read lock and allow 1700** the second process to proceed. 1701** 1702** ^The default busy callback is NULL. 1703** 1704** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1705** when SQLite is in the middle of a large transaction where all the 1706** changes will not fit into the in-memory cache. SQLite will 1707** already hold a RESERVED lock on the database file, but it needs 1708** to promote this lock to EXCLUSIVE so that it can spill cache 1709** pages into the database file without harm to concurrent 1710** readers. ^If it is unable to promote the lock, then the in-memory 1711** cache will be left in an inconsistent state and so the error 1712** code is promoted from the relatively benign [SQLITE_BUSY] to 1713** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1714** forces an automatic rollback of the changes. See the 1715** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1716** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1717** this is important. 1718** 1719** ^(There can only be a single busy handler defined for each 1720** [database connection]. Setting a new busy handler clears any 1721** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1722** will also set or clear the busy handler. 1723** 1724** The busy callback should not take any actions which modify the 1725** database connection that invoked the busy handler. Any such actions 1726** result in undefined behavior. 1727** 1728** A busy handler must not close the database connection 1729** or [prepared statement] that invoked the busy handler. 1730*/ 1731SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1732 1733/* 1734** CAPI3REF: Set A Busy Timeout 1735** 1736** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1737** for a specified amount of time when a table is locked. ^The handler 1738** will sleep multiple times until at least "ms" milliseconds of sleeping 1739** have accumulated. ^After at least "ms" milliseconds of sleeping, 1740** the handler returns 0 which causes [sqlite3_step()] to return 1741** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1742** 1743** ^Calling this routine with an argument less than or equal to zero 1744** turns off all busy handlers. 1745** 1746** ^(There can only be a single busy handler for a particular 1747** [database connection] any any given moment. If another busy handler 1748** was defined (using [sqlite3_busy_handler()]) prior to calling 1749** this routine, that other busy handler is cleared.)^ 1750*/ 1751SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); 1752 1753/* 1754** CAPI3REF: Convenience Routines For Running Queries 1755** 1756** This is a legacy interface that is preserved for backwards compatibility. 1757** Use of this interface is not recommended. 1758** 1759** Definition: A <b>result table</b> is memory data structure created by the 1760** [sqlite3_get_table()] interface. A result table records the 1761** complete query results from one or more queries. 1762** 1763** The table conceptually has a number of rows and columns. But 1764** these numbers are not part of the result table itself. These 1765** numbers are obtained separately. Let N be the number of rows 1766** and M be the number of columns. 1767** 1768** A result table is an array of pointers to zero-terminated UTF-8 strings. 1769** There are (N+1)*M elements in the array. The first M pointers point 1770** to zero-terminated strings that contain the names of the columns. 1771** The remaining entries all point to query results. NULL values result 1772** in NULL pointers. All other values are in their UTF-8 zero-terminated 1773** string representation as returned by [sqlite3_column_text()]. 1774** 1775** A result table might consist of one or more memory allocations. 1776** It is not safe to pass a result table directly to [sqlite3_free()]. 1777** A result table should be deallocated using [sqlite3_free_table()]. 1778** 1779** ^(As an example of the result table format, suppose a query result 1780** is as follows: 1781** 1782** <blockquote><pre> 1783** Name | Age 1784** ----------------------- 1785** Alice | 43 1786** Bob | 28 1787** Cindy | 21 1788** </pre></blockquote> 1789** 1790** There are two column (M==2) and three rows (N==3). Thus the 1791** result table has 8 entries. Suppose the result table is stored 1792** in an array names azResult. Then azResult holds this content: 1793** 1794** <blockquote><pre> 1795** azResult[0] = "Name"; 1796** azResult[1] = "Age"; 1797** azResult[2] = "Alice"; 1798** azResult[3] = "43"; 1799** azResult[4] = "Bob"; 1800** azResult[5] = "28"; 1801** azResult[6] = "Cindy"; 1802** azResult[7] = "21"; 1803** </pre></blockquote>)^ 1804** 1805** ^The sqlite3_get_table() function evaluates one or more 1806** semicolon-separated SQL statements in the zero-terminated UTF-8 1807** string of its 2nd parameter and returns a result table to the 1808** pointer given in its 3rd parameter. 1809** 1810** After the application has finished with the result from sqlite3_get_table(), 1811** it must pass the result table pointer to sqlite3_free_table() in order to 1812** release the memory that was malloced. Because of the way the 1813** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1814** function must not try to call [sqlite3_free()] directly. Only 1815** [sqlite3_free_table()] is able to release the memory properly and safely. 1816** 1817** The sqlite3_get_table() interface is implemented as a wrapper around 1818** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1819** to any internal data structures of SQLite. It uses only the public 1820** interface defined here. As a consequence, errors that occur in the 1821** wrapper layer outside of the internal [sqlite3_exec()] call are not 1822** reflected in subsequent calls to [sqlite3_errcode()] or 1823** [sqlite3_errmsg()]. 1824*/ 1825SQLITE_API int sqlite3_get_table( 1826 sqlite3 *db, /* An open database */ 1827 const char *zSql, /* SQL to be evaluated */ 1828 char ***pazResult, /* Results of the query */ 1829 int *pnRow, /* Number of result rows written here */ 1830 int *pnColumn, /* Number of result columns written here */ 1831 char **pzErrmsg /* Error msg written here */ 1832); 1833SQLITE_API void sqlite3_free_table(char **result); 1834 1835/* 1836** CAPI3REF: Formatted String Printing Functions 1837** 1838** These routines are work-alikes of the "printf()" family of functions 1839** from the standard C library. 1840** 1841** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1842** results into memory obtained from [sqlite3_malloc()]. 1843** The strings returned by these two routines should be 1844** released by [sqlite3_free()]. ^Both routines return a 1845** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1846** memory to hold the resulting string. 1847** 1848** ^(In sqlite3_snprintf() routine is similar to "snprintf()" from 1849** the standard C library. The result is written into the 1850** buffer supplied as the second parameter whose size is given by 1851** the first parameter. Note that the order of the 1852** first two parameters is reversed from snprintf().)^ This is an 1853** historical accident that cannot be fixed without breaking 1854** backwards compatibility. ^(Note also that sqlite3_snprintf() 1855** returns a pointer to its buffer instead of the number of 1856** characters actually written into the buffer.)^ We admit that 1857** the number of characters written would be a more useful return 1858** value but we cannot change the implementation of sqlite3_snprintf() 1859** now without breaking compatibility. 1860** 1861** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 1862** guarantees that the buffer is always zero-terminated. ^The first 1863** parameter "n" is the total size of the buffer, including space for 1864** the zero terminator. So the longest string that can be completely 1865** written will be n-1 characters. 1866** 1867** These routines all implement some additional formatting 1868** options that are useful for constructing SQL statements. 1869** All of the usual printf() formatting options apply. In addition, there 1870** is are "%q", "%Q", and "%z" options. 1871** 1872** ^(The %q option works like %s in that it substitutes a null-terminated 1873** string from the argument list. But %q also doubles every '\'' character. 1874** %q is designed for use inside a string literal.)^ By doubling each '\'' 1875** character it escapes that character and allows it to be inserted into 1876** the string. 1877** 1878** For example, assume the string variable zText contains text as follows: 1879** 1880** <blockquote><pre> 1881** char *zText = "It's a happy day!"; 1882** </pre></blockquote> 1883** 1884** One can use this text in an SQL statement as follows: 1885** 1886** <blockquote><pre> 1887** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1888** sqlite3_exec(db, zSQL, 0, 0, 0); 1889** sqlite3_free(zSQL); 1890** </pre></blockquote> 1891** 1892** Because the %q format string is used, the '\'' character in zText 1893** is escaped and the SQL generated is as follows: 1894** 1895** <blockquote><pre> 1896** INSERT INTO table1 VALUES('It''s a happy day!') 1897** </pre></blockquote> 1898** 1899** This is correct. Had we used %s instead of %q, the generated SQL 1900** would have looked like this: 1901** 1902** <blockquote><pre> 1903** INSERT INTO table1 VALUES('It's a happy day!'); 1904** </pre></blockquote> 1905** 1906** This second example is an SQL syntax error. As a general rule you should 1907** always use %q instead of %s when inserting text into a string literal. 1908** 1909** ^(The %Q option works like %q except it also adds single quotes around 1910** the outside of the total string. Additionally, if the parameter in the 1911** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1912** single quotes).)^ So, for example, one could say: 1913** 1914** <blockquote><pre> 1915** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1916** sqlite3_exec(db, zSQL, 0, 0, 0); 1917** sqlite3_free(zSQL); 1918** </pre></blockquote> 1919** 1920** The code above will render a correct SQL statement in the zSQL 1921** variable even if the zText variable is a NULL pointer. 1922** 1923** ^(The "%z" formatting option works like "%s" but with the 1924** addition that after the string has been read and copied into 1925** the result, [sqlite3_free()] is called on the input string.)^ 1926*/ 1927SQLITE_API char *sqlite3_mprintf(const char*,...); 1928SQLITE_API char *sqlite3_vmprintf(const char*, va_list); 1929SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); 1930 1931/* 1932** CAPI3REF: Memory Allocation Subsystem 1933** 1934** The SQLite core uses these three routines for all of its own 1935** internal memory allocation needs. "Core" in the previous sentence 1936** does not include operating-system specific VFS implementation. The 1937** Windows VFS uses native malloc() and free() for some operations. 1938** 1939** ^The sqlite3_malloc() routine returns a pointer to a block 1940** of memory at least N bytes in length, where N is the parameter. 1941** ^If sqlite3_malloc() is unable to obtain sufficient free 1942** memory, it returns a NULL pointer. ^If the parameter N to 1943** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1944** a NULL pointer. 1945** 1946** ^Calling sqlite3_free() with a pointer previously returned 1947** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1948** that it might be reused. ^The sqlite3_free() routine is 1949** a no-op if is called with a NULL pointer. Passing a NULL pointer 1950** to sqlite3_free() is harmless. After being freed, memory 1951** should neither be read nor written. Even reading previously freed 1952** memory might result in a segmentation fault or other severe error. 1953** Memory corruption, a segmentation fault, or other severe error 1954** might result if sqlite3_free() is called with a non-NULL pointer that 1955** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1956** 1957** ^(The sqlite3_realloc() interface attempts to resize a 1958** prior memory allocation to be at least N bytes, where N is the 1959** second parameter. The memory allocation to be resized is the first 1960** parameter.)^ ^ If the first parameter to sqlite3_realloc() 1961** is a NULL pointer then its behavior is identical to calling 1962** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1963** ^If the second parameter to sqlite3_realloc() is zero or 1964** negative then the behavior is exactly the same as calling 1965** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1966** ^sqlite3_realloc() returns a pointer to a memory allocation 1967** of at least N bytes in size or NULL if sufficient memory is unavailable. 1968** ^If M is the size of the prior allocation, then min(N,M) bytes 1969** of the prior allocation are copied into the beginning of buffer returned 1970** by sqlite3_realloc() and the prior allocation is freed. 1971** ^If sqlite3_realloc() returns NULL, then the prior allocation 1972** is not freed. 1973** 1974** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 1975** is always aligned to at least an 8 byte boundary, or to a 1976** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 1977** option is used. 1978** 1979** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1980** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1981** implementation of these routines to be omitted. That capability 1982** is no longer provided. Only built-in memory allocators can be used. 1983** 1984** The Windows OS interface layer calls 1985** the system malloc() and free() directly when converting 1986** filenames between the UTF-8 encoding used by SQLite 1987** and whatever filename encoding is used by the particular Windows 1988** installation. Memory allocation errors are detected, but 1989** they are reported back as [SQLITE_CANTOPEN] or 1990** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1991** 1992** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1993** must be either NULL or else pointers obtained from a prior 1994** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1995** not yet been released. 1996** 1997** The application must not read or write any part of 1998** a block of memory after it has been released using 1999** [sqlite3_free()] or [sqlite3_realloc()]. 2000*/ 2001SQLITE_API void *sqlite3_malloc(int); 2002SQLITE_API void *sqlite3_realloc(void*, int); 2003SQLITE_API void sqlite3_free(void*); 2004 2005/* 2006** CAPI3REF: Memory Allocator Statistics 2007** 2008** SQLite provides these two interfaces for reporting on the status 2009** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2010** routines, which form the built-in memory allocation subsystem. 2011** 2012** ^The [sqlite3_memory_used()] routine returns the number of bytes 2013** of memory currently outstanding (malloced but not freed). 2014** ^The [sqlite3_memory_highwater()] routine returns the maximum 2015** value of [sqlite3_memory_used()] since the high-water mark 2016** was last reset. ^The values returned by [sqlite3_memory_used()] and 2017** [sqlite3_memory_highwater()] include any overhead 2018** added by SQLite in its implementation of [sqlite3_malloc()], 2019** but not overhead added by the any underlying system library 2020** routines that [sqlite3_malloc()] may call. 2021** 2022** ^The memory high-water mark is reset to the current value of 2023** [sqlite3_memory_used()] if and only if the parameter to 2024** [sqlite3_memory_highwater()] is true. ^The value returned 2025** by [sqlite3_memory_highwater(1)] is the high-water mark 2026** prior to the reset. 2027*/ 2028SQLITE_API sqlite3_int64 sqlite3_memory_used(void); 2029SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2030 2031/* 2032** CAPI3REF: Pseudo-Random Number Generator 2033** 2034** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2035** select random [ROWID | ROWIDs] when inserting new records into a table that 2036** already uses the largest possible [ROWID]. The PRNG is also used for 2037** the build-in random() and randomblob() SQL functions. This interface allows 2038** applications to access the same PRNG for other purposes. 2039** 2040** ^A call to this routine stores N bytes of randomness into buffer P. 2041** 2042** ^The first time this routine is invoked (either internally or by 2043** the application) the PRNG is seeded using randomness obtained 2044** from the xRandomness method of the default [sqlite3_vfs] object. 2045** ^On all subsequent invocations, the pseudo-randomness is generated 2046** internally and without recourse to the [sqlite3_vfs] xRandomness 2047** method. 2048*/ 2049SQLITE_API void sqlite3_randomness(int N, void *P); 2050 2051/* 2052** CAPI3REF: Compile-Time Authorization Callbacks 2053** 2054** ^This routine registers a authorizer callback with a particular 2055** [database connection], supplied in the first argument. 2056** ^The authorizer callback is invoked as SQL statements are being compiled 2057** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2058** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2059** points during the compilation process, as logic is being created 2060** to perform various actions, the authorizer callback is invoked to 2061** see if those actions are allowed. ^The authorizer callback should 2062** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2063** specific action but allow the SQL statement to continue to be 2064** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2065** rejected with an error. ^If the authorizer callback returns 2066** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2067** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2068** the authorizer will fail with an error message. 2069** 2070** When the callback returns [SQLITE_OK], that means the operation 2071** requested is ok. ^When the callback returns [SQLITE_DENY], the 2072** [sqlite3_prepare_v2()] or equivalent call that triggered the 2073** authorizer will fail with an error message explaining that 2074** access is denied. 2075** 2076** ^The first parameter to the authorizer callback is a copy of the third 2077** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2078** to the callback is an integer [SQLITE_COPY | action code] that specifies 2079** the particular action to be authorized. ^The third through sixth parameters 2080** to the callback are zero-terminated strings that contain additional 2081** details about the action to be authorized. 2082** 2083** ^If the action code is [SQLITE_READ] 2084** and the callback returns [SQLITE_IGNORE] then the 2085** [prepared statement] statement is constructed to substitute 2086** a NULL value in place of the table column that would have 2087** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2088** return can be used to deny an untrusted user access to individual 2089** columns of a table. 2090** ^If the action code is [SQLITE_DELETE] and the callback returns 2091** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2092** [truncate optimization] is disabled and all rows are deleted individually. 2093** 2094** An authorizer is used when [sqlite3_prepare | preparing] 2095** SQL statements from an untrusted source, to ensure that the SQL statements 2096** do not try to access data they are not allowed to see, or that they do not 2097** try to execute malicious statements that damage the database. For 2098** example, an application may allow a user to enter arbitrary 2099** SQL queries for evaluation by a database. But the application does 2100** not want the user to be able to make arbitrary changes to the 2101** database. An authorizer could then be put in place while the 2102** user-entered SQL is being [sqlite3_prepare | prepared] that 2103** disallows everything except [SELECT] statements. 2104** 2105** Applications that need to process SQL from untrusted sources 2106** might also consider lowering resource limits using [sqlite3_limit()] 2107** and limiting database size using the [max_page_count] [PRAGMA] 2108** in addition to using an authorizer. 2109** 2110** ^(Only a single authorizer can be in place on a database connection 2111** at a time. Each call to sqlite3_set_authorizer overrides the 2112** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2113** The authorizer is disabled by default. 2114** 2115** The authorizer callback must not do anything that will modify 2116** the database connection that invoked the authorizer callback. 2117** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2118** database connections for the meaning of "modify" in this paragraph. 2119** 2120** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2121** statement might be re-prepared during [sqlite3_step()] due to a 2122** schema change. Hence, the application should ensure that the 2123** correct authorizer callback remains in place during the [sqlite3_step()]. 2124** 2125** ^Note that the authorizer callback is invoked only during 2126** [sqlite3_prepare()] or its variants. Authorization is not 2127** performed during statement evaluation in [sqlite3_step()], unless 2128** as stated in the previous paragraph, sqlite3_step() invokes 2129** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2130*/ 2131SQLITE_API int sqlite3_set_authorizer( 2132 sqlite3*, 2133 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2134 void *pUserData 2135); 2136 2137/* 2138** CAPI3REF: Authorizer Return Codes 2139** 2140** The [sqlite3_set_authorizer | authorizer callback function] must 2141** return either [SQLITE_OK] or one of these two constants in order 2142** to signal SQLite whether or not the action is permitted. See the 2143** [sqlite3_set_authorizer | authorizer documentation] for additional 2144** information. 2145*/ 2146#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2147#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2148 2149/* 2150** CAPI3REF: Authorizer Action Codes 2151** 2152** The [sqlite3_set_authorizer()] interface registers a callback function 2153** that is invoked to authorize certain SQL statement actions. The 2154** second parameter to the callback is an integer code that specifies 2155** what action is being authorized. These are the integer action codes that 2156** the authorizer callback may be passed. 2157** 2158** These action code values signify what kind of operation is to be 2159** authorized. The 3rd and 4th parameters to the authorization 2160** callback function will be parameters or NULL depending on which of these 2161** codes is used as the second parameter. ^(The 5th parameter to the 2162** authorizer callback is the name of the database ("main", "temp", 2163** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2164** is the name of the inner-most trigger or view that is responsible for 2165** the access attempt or NULL if this access attempt is directly from 2166** top-level SQL code. 2167*/ 2168/******************************************* 3rd ************ 4th ***********/ 2169#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2170#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2171#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2172#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2173#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2174#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2175#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2176#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2177#define SQLITE_DELETE 9 /* Table Name NULL */ 2178#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2179#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2180#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2181#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2182#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2183#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2184#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2185#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2186#define SQLITE_INSERT 18 /* Table Name NULL */ 2187#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2188#define SQLITE_READ 20 /* Table Name Column Name */ 2189#define SQLITE_SELECT 21 /* NULL NULL */ 2190#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2191#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2192#define SQLITE_ATTACH 24 /* Filename NULL */ 2193#define SQLITE_DETACH 25 /* Database Name NULL */ 2194#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2195#define SQLITE_REINDEX 27 /* Index Name NULL */ 2196#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2197#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2198#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2199#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2200#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2201#define SQLITE_COPY 0 /* No longer used */ 2202 2203/* 2204** CAPI3REF: Tracing And Profiling Functions 2205** 2206** These routines register callback functions that can be used for 2207** tracing and profiling the execution of SQL statements. 2208** 2209** ^The callback function registered by sqlite3_trace() is invoked at 2210** various times when an SQL statement is being run by [sqlite3_step()]. 2211** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2212** SQL statement text as the statement first begins executing. 2213** ^(Additional sqlite3_trace() callbacks might occur 2214** as each triggered subprogram is entered. The callbacks for triggers 2215** contain a UTF-8 SQL comment that identifies the trigger.)^ 2216** 2217** ^The callback function registered by sqlite3_profile() is invoked 2218** as each SQL statement finishes. ^The profile callback contains 2219** the original statement text and an estimate of wall-clock time 2220** of how long that statement took to run. ^The profile callback 2221** time is in units of nanoseconds, however the current implementation 2222** is only capable of millisecond resolution so the six least significant 2223** digits in the time are meaningless. Future versions of SQLite 2224** might provide greater resolution on the profiler callback. The 2225** sqlite3_profile() function is considered experimental and is 2226** subject to change in future versions of SQLite. 2227*/ 2228SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2229SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2230 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2231 2232/* 2233** CAPI3REF: Query Progress Callbacks 2234** 2235** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2236** function X to be invoked periodically during long running calls to 2237** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2238** database connection D. An example use for this 2239** interface is to keep a GUI updated during a large query. 2240** 2241** ^The parameter P is passed through as the only parameter to the 2242** callback function X. ^The parameter N is the number of 2243** [virtual machine instructions] that are evaluated between successive 2244** invocations of the callback X. 2245** 2246** ^Only a single progress handler may be defined at one time per 2247** [database connection]; setting a new progress handler cancels the 2248** old one. ^Setting parameter X to NULL disables the progress handler. 2249** ^The progress handler is also disabled by setting N to a value less 2250** than 1. 2251** 2252** ^If the progress callback returns non-zero, the operation is 2253** interrupted. This feature can be used to implement a 2254** "Cancel" button on a GUI progress dialog box. 2255** 2256** The progress handler callback must not do anything that will modify 2257** the database connection that invoked the progress handler. 2258** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2259** database connections for the meaning of "modify" in this paragraph. 2260** 2261*/ 2262SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2263 2264/* 2265** CAPI3REF: Opening A New Database Connection 2266** 2267** ^These routines open an SQLite database file whose name is given by the 2268** filename argument. ^The filename argument is interpreted as UTF-8 for 2269** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2270** order for sqlite3_open16(). ^(A [database connection] handle is usually 2271** returned in *ppDb, even if an error occurs. The only exception is that 2272** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2273** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2274** object.)^ ^(If the database is opened (and/or created) successfully, then 2275** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2276** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2277** an English language description of the error following a failure of any 2278** of the sqlite3_open() routines. 2279** 2280** ^The default encoding for the database will be UTF-8 if 2281** sqlite3_open() or sqlite3_open_v2() is called and 2282** UTF-16 in the native byte order if sqlite3_open16() is used. 2283** 2284** Whether or not an error occurs when it is opened, resources 2285** associated with the [database connection] handle should be released by 2286** passing it to [sqlite3_close()] when it is no longer required. 2287** 2288** The sqlite3_open_v2() interface works like sqlite3_open() 2289** except that it accepts two additional parameters for additional control 2290** over the new database connection. ^(The flags parameter to 2291** sqlite3_open_v2() can take one of 2292** the following three values, optionally combined with the 2293** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2294** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^ 2295** 2296** <dl> 2297** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2298** <dd>The database is opened in read-only mode. If the database does not 2299** already exist, an error is returned.</dd>)^ 2300** 2301** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2302** <dd>The database is opened for reading and writing if possible, or reading 2303** only if the file is write protected by the operating system. In either 2304** case the database must already exist, otherwise an error is returned.</dd>)^ 2305** 2306** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2307** <dd>The database is opened for reading and writing, and is creates it if 2308** it does not already exist. This is the behavior that is always used for 2309** sqlite3_open() and sqlite3_open16().</dd>)^ 2310** </dl> 2311** 2312** If the 3rd parameter to sqlite3_open_v2() is not one of the 2313** combinations shown above or one of the combinations shown above combined 2314** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], 2315** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_PRIVATECACHE] flags, 2316** then the behavior is undefined. 2317** 2318** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2319** opens in the multi-thread [threading mode] as long as the single-thread 2320** mode has not been set at compile-time or start-time. ^If the 2321** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2322** in the serialized [threading mode] unless single-thread was 2323** previously selected at compile-time or start-time. 2324** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2325** eligible to use [shared cache mode], regardless of whether or not shared 2326** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2327** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2328** participate in [shared cache mode] even if it is enabled. 2329** 2330** ^If the filename is ":memory:", then a private, temporary in-memory database 2331** is created for the connection. ^This in-memory database will vanish when 2332** the database connection is closed. Future versions of SQLite might 2333** make use of additional special filenames that begin with the ":" character. 2334** It is recommended that when a database filename actually does begin with 2335** a ":" character you should prefix the filename with a pathname such as 2336** "./" to avoid ambiguity. 2337** 2338** ^If the filename is an empty string, then a private, temporary 2339** on-disk database will be created. ^This private database will be 2340** automatically deleted as soon as the database connection is closed. 2341** 2342** ^The fourth parameter to sqlite3_open_v2() is the name of the 2343** [sqlite3_vfs] object that defines the operating system interface that 2344** the new database connection should use. ^If the fourth parameter is 2345** a NULL pointer then the default [sqlite3_vfs] object is used. 2346** 2347** <b>Note to Windows users:</b> The encoding used for the filename argument 2348** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2349** codepage is currently defined. Filenames containing international 2350** characters must be converted to UTF-8 prior to passing them into 2351** sqlite3_open() or sqlite3_open_v2(). 2352*/ 2353SQLITE_API int sqlite3_open( 2354 const char *filename, /* Database filename (UTF-8) */ 2355 sqlite3 **ppDb /* OUT: SQLite db handle */ 2356); 2357SQLITE_API int sqlite3_open16( 2358 const void *filename, /* Database filename (UTF-16) */ 2359 sqlite3 **ppDb /* OUT: SQLite db handle */ 2360); 2361SQLITE_API int sqlite3_open_v2( 2362 const char *filename, /* Database filename (UTF-8) */ 2363 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2364 int flags, /* Flags */ 2365 const char *zVfs /* Name of VFS module to use */ 2366); 2367 2368/* 2369** CAPI3REF: Error Codes And Messages 2370** 2371** ^The sqlite3_errcode() interface returns the numeric [result code] or 2372** [extended result code] for the most recent failed sqlite3_* API call 2373** associated with a [database connection]. If a prior API call failed 2374** but the most recent API call succeeded, the return value from 2375** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2376** interface is the same except that it always returns the 2377** [extended result code] even when extended result codes are 2378** disabled. 2379** 2380** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2381** text that describes the error, as either UTF-8 or UTF-16 respectively. 2382** ^(Memory to hold the error message string is managed internally. 2383** The application does not need to worry about freeing the result. 2384** However, the error string might be overwritten or deallocated by 2385** subsequent calls to other SQLite interface functions.)^ 2386** 2387** When the serialized [threading mode] is in use, it might be the 2388** case that a second error occurs on a separate thread in between 2389** the time of the first error and the call to these interfaces. 2390** When that happens, the second error will be reported since these 2391** interfaces always report the most recent result. To avoid 2392** this, each thread can obtain exclusive use of the [database connection] D 2393** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2394** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2395** all calls to the interfaces listed here are completed. 2396** 2397** If an interface fails with SQLITE_MISUSE, that means the interface 2398** was invoked incorrectly by the application. In that case, the 2399** error code and message may or may not be set. 2400*/ 2401SQLITE_API int sqlite3_errcode(sqlite3 *db); 2402SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); 2403SQLITE_API const char *sqlite3_errmsg(sqlite3*); 2404SQLITE_API const void *sqlite3_errmsg16(sqlite3*); 2405 2406/* 2407** CAPI3REF: SQL Statement Object 2408** KEYWORDS: {prepared statement} {prepared statements} 2409** 2410** An instance of this object represents a single SQL statement. 2411** This object is variously known as a "prepared statement" or a 2412** "compiled SQL statement" or simply as a "statement". 2413** 2414** The life of a statement object goes something like this: 2415** 2416** <ol> 2417** <li> Create the object using [sqlite3_prepare_v2()] or a related 2418** function. 2419** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2420** interfaces. 2421** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2422** <li> Reset the statement using [sqlite3_reset()] then go back 2423** to step 2. Do this zero or more times. 2424** <li> Destroy the object using [sqlite3_finalize()]. 2425** </ol> 2426** 2427** Refer to documentation on individual methods above for additional 2428** information. 2429*/ 2430typedef struct sqlite3_stmt sqlite3_stmt; 2431 2432/* 2433** CAPI3REF: Run-time Limits 2434** 2435** ^(This interface allows the size of various constructs to be limited 2436** on a connection by connection basis. The first parameter is the 2437** [database connection] whose limit is to be set or queried. The 2438** second parameter is one of the [limit categories] that define a 2439** class of constructs to be size limited. The third parameter is the 2440** new limit for that construct.)^ 2441** 2442** ^If the new limit is a negative number, the limit is unchanged. 2443** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2444** [limits | hard upper bound] 2445** set at compile-time by a C preprocessor macro called 2446** [limits | SQLITE_MAX_<i>NAME</i>]. 2447** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2448** ^Attempts to increase a limit above its hard upper bound are 2449** silently truncated to the hard upper bound. 2450** 2451** ^Regardless of whether or not the limit was changed, the 2452** [sqlite3_limit()] interface returns the prior value of the limit. 2453** ^Hence, to find the current value of a limit without changing it, 2454** simply invoke this interface with the third parameter set to -1. 2455** 2456** Run-time limits are intended for use in applications that manage 2457** both their own internal database and also databases that are controlled 2458** by untrusted external sources. An example application might be a 2459** web browser that has its own databases for storing history and 2460** separate databases controlled by JavaScript applications downloaded 2461** off the Internet. The internal databases can be given the 2462** large, default limits. Databases managed by external sources can 2463** be given much smaller limits designed to prevent a denial of service 2464** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2465** interface to further control untrusted SQL. The size of the database 2466** created by an untrusted script can be contained using the 2467** [max_page_count] [PRAGMA]. 2468** 2469** New run-time limit categories may be added in future releases. 2470*/ 2471SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); 2472 2473/* 2474** CAPI3REF: Run-Time Limit Categories 2475** KEYWORDS: {limit category} {*limit categories} 2476** 2477** These constants define various performance limits 2478** that can be lowered at run-time using [sqlite3_limit()]. 2479** The synopsis of the meanings of the various limits is shown below. 2480** Additional information is available at [limits | Limits in SQLite]. 2481** 2482** <dl> 2483** ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2484** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2485** 2486** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2487** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2488** 2489** ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2490** <dd>The maximum number of columns in a table definition or in the 2491** result set of a [SELECT] or the maximum number of columns in an index 2492** or in an ORDER BY or GROUP BY clause.</dd>)^ 2493** 2494** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2495** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2496** 2497** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2498** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2499** 2500** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2501** <dd>The maximum number of instructions in a virtual machine program 2502** used to implement an SQL statement. This limit is not currently 2503** enforced, though that might be added in some future release of 2504** SQLite.</dd>)^ 2505** 2506** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2507** <dd>The maximum number of arguments on a function.</dd>)^ 2508** 2509** ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2510** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2511** 2512** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2513** <dd>The maximum length of the pattern argument to the [LIKE] or 2514** [GLOB] operators.</dd>)^ 2515** 2516** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2517** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2518** 2519** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2520** <dd>The maximum depth of recursion for triggers.</dd>)^ 2521** </dl> 2522*/ 2523#define SQLITE_LIMIT_LENGTH 0 2524#define SQLITE_LIMIT_SQL_LENGTH 1 2525#define SQLITE_LIMIT_COLUMN 2 2526#define SQLITE_LIMIT_EXPR_DEPTH 3 2527#define SQLITE_LIMIT_COMPOUND_SELECT 4 2528#define SQLITE_LIMIT_VDBE_OP 5 2529#define SQLITE_LIMIT_FUNCTION_ARG 6 2530#define SQLITE_LIMIT_ATTACHED 7 2531#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2532#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2533#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2534 2535/* 2536** CAPI3REF: Compiling An SQL Statement 2537** KEYWORDS: {SQL statement compiler} 2538** 2539** To execute an SQL query, it must first be compiled into a byte-code 2540** program using one of these routines. 2541** 2542** The first argument, "db", is a [database connection] obtained from a 2543** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2544** [sqlite3_open16()]. The database connection must not have been closed. 2545** 2546** The second argument, "zSql", is the statement to be compiled, encoded 2547** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2548** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2549** use UTF-16. 2550** 2551** ^If the nByte argument is less than zero, then zSql is read up to the 2552** first zero terminator. ^If nByte is non-negative, then it is the maximum 2553** number of bytes read from zSql. ^When nByte is non-negative, the 2554** zSql string ends at either the first '\000' or '\u0000' character or 2555** the nByte-th byte, whichever comes first. If the caller knows 2556** that the supplied string is nul-terminated, then there is a small 2557** performance advantage to be gained by passing an nByte parameter that 2558** is equal to the number of bytes in the input string <i>including</i> 2559** the nul-terminator bytes. 2560** 2561** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2562** past the end of the first SQL statement in zSql. These routines only 2563** compile the first statement in zSql, so *pzTail is left pointing to 2564** what remains uncompiled. 2565** 2566** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2567** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2568** to NULL. ^If the input text contains no SQL (if the input is an empty 2569** string or a comment) then *ppStmt is set to NULL. 2570** The calling procedure is responsible for deleting the compiled 2571** SQL statement using [sqlite3_finalize()] after it has finished with it. 2572** ppStmt may not be NULL. 2573** 2574** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2575** otherwise an [error code] is returned. 2576** 2577** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2578** recommended for all new programs. The two older interfaces are retained 2579** for backwards compatibility, but their use is discouraged. 2580** ^In the "v2" interfaces, the prepared statement 2581** that is returned (the [sqlite3_stmt] object) contains a copy of the 2582** original SQL text. This causes the [sqlite3_step()] interface to 2583** behave differently in three ways: 2584** 2585** <ol> 2586** <li> 2587** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2588** always used to do, [sqlite3_step()] will automatically recompile the SQL 2589** statement and try to run it again. 2590** </li> 2591** 2592** <li> 2593** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2594** [error codes] or [extended error codes]. ^The legacy behavior was that 2595** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2596** and the application would have to make a second call to [sqlite3_reset()] 2597** in order to find the underlying cause of the problem. With the "v2" prepare 2598** interfaces, the underlying reason for the error is returned immediately. 2599** </li> 2600** 2601** <li> 2602** ^If the specific value bound to [parameter | host parameter] in the 2603** WHERE clause might influence the choice of query plan for a statement, 2604** then the statement will be automatically recompiled, as if there had been 2605** a schema change, on the first [sqlite3_step()] call following any change 2606** to the [sqlite3_bind_text | bindings] of that [parameter]. 2607** ^The specific value of WHERE-clause [parameter] might influence the 2608** choice of query plan if the parameter is the left-hand side of a [LIKE] 2609** or [GLOB] operator or if the parameter is compared to an indexed column 2610** and the [SQLITE_ENABLE_STAT2] compile-time option is enabled. 2611** the 2612** </li> 2613** </ol> 2614*/ 2615SQLITE_API int sqlite3_prepare( 2616 sqlite3 *db, /* Database handle */ 2617 const char *zSql, /* SQL statement, UTF-8 encoded */ 2618 int nByte, /* Maximum length of zSql in bytes. */ 2619 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2620 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2621); 2622SQLITE_API int sqlite3_prepare_v2( 2623 sqlite3 *db, /* Database handle */ 2624 const char *zSql, /* SQL statement, UTF-8 encoded */ 2625 int nByte, /* Maximum length of zSql in bytes. */ 2626 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2627 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2628); 2629SQLITE_API int sqlite3_prepare16( 2630 sqlite3 *db, /* Database handle */ 2631 const void *zSql, /* SQL statement, UTF-16 encoded */ 2632 int nByte, /* Maximum length of zSql in bytes. */ 2633 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2634 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2635); 2636SQLITE_API int sqlite3_prepare16_v2( 2637 sqlite3 *db, /* Database handle */ 2638 const void *zSql, /* SQL statement, UTF-16 encoded */ 2639 int nByte, /* Maximum length of zSql in bytes. */ 2640 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2641 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2642); 2643 2644/* 2645** CAPI3REF: Retrieving Statement SQL 2646** 2647** ^This interface can be used to retrieve a saved copy of the original 2648** SQL text used to create a [prepared statement] if that statement was 2649** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2650*/ 2651SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); 2652 2653/* 2654** CAPI3REF: Determine If An SQL Statement Writes The Database 2655** 2656** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 2657** the [prepared statement] X is [SELECT] statement and false (zero) if 2658** X is an [INSERT], [UPDATE], [DELETE], CREATE, DROP, [ANALYZE], 2659** [ALTER], or [REINDEX] statement. 2660** If X is a NULL pointer or any other kind of statement, including but 2661** not limited to [ATTACH], [DETACH], [COMMIT], [ROLLBACK], [RELEASE], 2662** [SAVEPOINT], [PRAGMA], or [VACUUM] the result of sqlite3_stmt_readonly(X) is 2663** undefined. 2664*/ 2665SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 2666 2667/* 2668** CAPI3REF: Dynamically Typed Value Object 2669** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2670** 2671** SQLite uses the sqlite3_value object to represent all values 2672** that can be stored in a database table. SQLite uses dynamic typing 2673** for the values it stores. ^Values stored in sqlite3_value objects 2674** can be integers, floating point values, strings, BLOBs, or NULL. 2675** 2676** An sqlite3_value object may be either "protected" or "unprotected". 2677** Some interfaces require a protected sqlite3_value. Other interfaces 2678** will accept either a protected or an unprotected sqlite3_value. 2679** Every interface that accepts sqlite3_value arguments specifies 2680** whether or not it requires a protected sqlite3_value. 2681** 2682** The terms "protected" and "unprotected" refer to whether or not 2683** a mutex is held. A internal mutex is held for a protected 2684** sqlite3_value object but no mutex is held for an unprotected 2685** sqlite3_value object. If SQLite is compiled to be single-threaded 2686** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2687** or if SQLite is run in one of reduced mutex modes 2688** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2689** then there is no distinction between protected and unprotected 2690** sqlite3_value objects and they can be used interchangeably. However, 2691** for maximum code portability it is recommended that applications 2692** still make the distinction between protected and unprotected 2693** sqlite3_value objects even when not strictly required. 2694** 2695** ^The sqlite3_value objects that are passed as parameters into the 2696** implementation of [application-defined SQL functions] are protected. 2697** ^The sqlite3_value object returned by 2698** [sqlite3_column_value()] is unprotected. 2699** Unprotected sqlite3_value objects may only be used with 2700** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2701** The [sqlite3_value_blob | sqlite3_value_type()] family of 2702** interfaces require protected sqlite3_value objects. 2703*/ 2704typedef struct Mem sqlite3_value; 2705 2706/* 2707** CAPI3REF: SQL Function Context Object 2708** 2709** The context in which an SQL function executes is stored in an 2710** sqlite3_context object. ^A pointer to an sqlite3_context object 2711** is always first parameter to [application-defined SQL functions]. 2712** The application-defined SQL function implementation will pass this 2713** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2714** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2715** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2716** and/or [sqlite3_set_auxdata()]. 2717*/ 2718typedef struct sqlite3_context sqlite3_context; 2719 2720/* 2721** CAPI3REF: Binding Values To Prepared Statements 2722** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2723** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2724** 2725** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 2726** literals may be replaced by a [parameter] that matches one of following 2727** templates: 2728** 2729** <ul> 2730** <li> ? 2731** <li> ?NNN 2732** <li> :VVV 2733** <li> @VVV 2734** <li> $VVV 2735** </ul> 2736** 2737** In the templates above, NNN represents an integer literal, 2738** and VVV represents an alphanumeric identifier.)^ ^The values of these 2739** parameters (also called "host parameter names" or "SQL parameters") 2740** can be set using the sqlite3_bind_*() routines defined here. 2741** 2742** ^The first argument to the sqlite3_bind_*() routines is always 2743** a pointer to the [sqlite3_stmt] object returned from 2744** [sqlite3_prepare_v2()] or its variants. 2745** 2746** ^The second argument is the index of the SQL parameter to be set. 2747** ^The leftmost SQL parameter has an index of 1. ^When the same named 2748** SQL parameter is used more than once, second and subsequent 2749** occurrences have the same index as the first occurrence. 2750** ^The index for named parameters can be looked up using the 2751** [sqlite3_bind_parameter_index()] API if desired. ^The index 2752** for "?NNN" parameters is the value of NNN. 2753** ^The NNN value must be between 1 and the [sqlite3_limit()] 2754** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2755** 2756** ^The third argument is the value to bind to the parameter. 2757** 2758** ^(In those routines that have a fourth argument, its value is the 2759** number of bytes in the parameter. To be clear: the value is the 2760** number of <u>bytes</u> in the value, not the number of characters.)^ 2761** ^If the fourth parameter is negative, the length of the string is 2762** the number of bytes up to the first zero terminator. 2763** 2764** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2765** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2766** string after SQLite has finished with it. ^The destructor is called 2767** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 2768** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 2769** ^If the fifth argument is 2770** the special value [SQLITE_STATIC], then SQLite assumes that the 2771** information is in static, unmanaged space and does not need to be freed. 2772** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 2773** SQLite makes its own private copy of the data immediately, before 2774** the sqlite3_bind_*() routine returns. 2775** 2776** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2777** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 2778** (just an integer to hold its size) while it is being processed. 2779** Zeroblobs are intended to serve as placeholders for BLOBs whose 2780** content is later written using 2781** [sqlite3_blob_open | incremental BLOB I/O] routines. 2782** ^A negative value for the zeroblob results in a zero-length BLOB. 2783** 2784** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 2785** for the [prepared statement] or with a prepared statement for which 2786** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 2787** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 2788** routine is passed a [prepared statement] that has been finalized, the 2789** result is undefined and probably harmful. 2790** 2791** ^Bindings are not cleared by the [sqlite3_reset()] routine. 2792** ^Unbound parameters are interpreted as NULL. 2793** 2794** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 2795** [error code] if anything goes wrong. 2796** ^[SQLITE_RANGE] is returned if the parameter 2797** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 2798** 2799** See also: [sqlite3_bind_parameter_count()], 2800** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2801*/ 2802SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2803SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); 2804SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); 2805SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2806SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); 2807SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2808SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2809SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2810SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2811 2812/* 2813** CAPI3REF: Number Of SQL Parameters 2814** 2815** ^This routine can be used to find the number of [SQL parameters] 2816** in a [prepared statement]. SQL parameters are tokens of the 2817** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2818** placeholders for values that are [sqlite3_bind_blob | bound] 2819** to the parameters at a later time. 2820** 2821** ^(This routine actually returns the index of the largest (rightmost) 2822** parameter. For all forms except ?NNN, this will correspond to the 2823** number of unique parameters. If parameters of the ?NNN form are used, 2824** there may be gaps in the list.)^ 2825** 2826** See also: [sqlite3_bind_blob|sqlite3_bind()], 2827** [sqlite3_bind_parameter_name()], and 2828** [sqlite3_bind_parameter_index()]. 2829*/ 2830SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); 2831 2832/* 2833** CAPI3REF: Name Of A Host Parameter 2834** 2835** ^The sqlite3_bind_parameter_name(P,N) interface returns 2836** the name of the N-th [SQL parameter] in the [prepared statement] P. 2837** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2838** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2839** respectively. 2840** In other words, the initial ":" or "$" or "@" or "?" 2841** is included as part of the name.)^ 2842** ^Parameters of the form "?" without a following integer have no name 2843** and are referred to as "nameless" or "anonymous parameters". 2844** 2845** ^The first host parameter has an index of 1, not 0. 2846** 2847** ^If the value N is out of range or if the N-th parameter is 2848** nameless, then NULL is returned. ^The returned string is 2849** always in UTF-8 encoding even if the named parameter was 2850** originally specified as UTF-16 in [sqlite3_prepare16()] or 2851** [sqlite3_prepare16_v2()]. 2852** 2853** See also: [sqlite3_bind_blob|sqlite3_bind()], 2854** [sqlite3_bind_parameter_count()], and 2855** [sqlite3_bind_parameter_index()]. 2856*/ 2857SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2858 2859/* 2860** CAPI3REF: Index Of A Parameter With A Given Name 2861** 2862** ^Return the index of an SQL parameter given its name. ^The 2863** index value returned is suitable for use as the second 2864** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 2865** is returned if no matching parameter is found. ^The parameter 2866** name must be given in UTF-8 even if the original statement 2867** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2868** 2869** See also: [sqlite3_bind_blob|sqlite3_bind()], 2870** [sqlite3_bind_parameter_count()], and 2871** [sqlite3_bind_parameter_index()]. 2872*/ 2873SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2874 2875/* 2876** CAPI3REF: Reset All Bindings On A Prepared Statement 2877** 2878** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 2879** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2880** ^Use this routine to reset all host parameters to NULL. 2881*/ 2882SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); 2883 2884/* 2885** CAPI3REF: Number Of Columns In A Result Set 2886** 2887** ^Return the number of columns in the result set returned by the 2888** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 2889** statement that does not return data (for example an [UPDATE]). 2890** 2891** See also: [sqlite3_data_count()] 2892*/ 2893SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); 2894 2895/* 2896** CAPI3REF: Column Names In A Result Set 2897** 2898** ^These routines return the name assigned to a particular column 2899** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 2900** interface returns a pointer to a zero-terminated UTF-8 string 2901** and sqlite3_column_name16() returns a pointer to a zero-terminated 2902** UTF-16 string. ^The first parameter is the [prepared statement] 2903** that implements the [SELECT] statement. ^The second parameter is the 2904** column number. ^The leftmost column is number 0. 2905** 2906** ^The returned string pointer is valid until either the [prepared statement] 2907** is destroyed by [sqlite3_finalize()] or until the next call to 2908** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2909** 2910** ^If sqlite3_malloc() fails during the processing of either routine 2911** (for example during a conversion from UTF-8 to UTF-16) then a 2912** NULL pointer is returned. 2913** 2914** ^The name of a result column is the value of the "AS" clause for 2915** that column, if there is an AS clause. If there is no AS clause 2916** then the name of the column is unspecified and may change from 2917** one release of SQLite to the next. 2918*/ 2919SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); 2920SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2921 2922/* 2923** CAPI3REF: Source Of Data In A Query Result 2924** 2925** ^These routines provide a means to determine the database, table, and 2926** table column that is the origin of a particular result column in 2927** [SELECT] statement. 2928** ^The name of the database or table or column can be returned as 2929** either a UTF-8 or UTF-16 string. ^The _database_ routines return 2930** the database name, the _table_ routines return the table name, and 2931** the origin_ routines return the column name. 2932** ^The returned string is valid until the [prepared statement] is destroyed 2933** using [sqlite3_finalize()] or until the same information is requested 2934** again in a different encoding. 2935** 2936** ^The names returned are the original un-aliased names of the 2937** database, table, and column. 2938** 2939** ^The first argument to these interfaces is a [prepared statement]. 2940** ^These functions return information about the Nth result column returned by 2941** the statement, where N is the second function argument. 2942** ^The left-most column is column 0 for these routines. 2943** 2944** ^If the Nth column returned by the statement is an expression or 2945** subquery and is not a column value, then all of these functions return 2946** NULL. ^These routine might also return NULL if a memory allocation error 2947** occurs. ^Otherwise, they return the name of the attached database, table, 2948** or column that query result column was extracted from. 2949** 2950** ^As with all other SQLite APIs, those whose names end with "16" return 2951** UTF-16 encoded strings and the other functions return UTF-8. 2952** 2953** ^These APIs are only available if the library was compiled with the 2954** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 2955** 2956** If two or more threads call one or more of these routines against the same 2957** prepared statement and column at the same time then the results are 2958** undefined. 2959** 2960** If two or more threads call one or more 2961** [sqlite3_column_database_name | column metadata interfaces] 2962** for the same [prepared statement] and result column 2963** at the same time then the results are undefined. 2964*/ 2965SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2966SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2967SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2968SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2969SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2970SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2971 2972/* 2973** CAPI3REF: Declared Datatype Of A Query Result 2974** 2975** ^(The first parameter is a [prepared statement]. 2976** If this statement is a [SELECT] statement and the Nth column of the 2977** returned result set of that [SELECT] is a table column (not an 2978** expression or subquery) then the declared type of the table 2979** column is returned.)^ ^If the Nth column of the result set is an 2980** expression or subquery, then a NULL pointer is returned. 2981** ^The returned string is always UTF-8 encoded. 2982** 2983** ^(For example, given the database schema: 2984** 2985** CREATE TABLE t1(c1 VARIANT); 2986** 2987** and the following statement to be compiled: 2988** 2989** SELECT c1 + 1, c1 FROM t1; 2990** 2991** this routine would return the string "VARIANT" for the second result 2992** column (i==1), and a NULL pointer for the first result column (i==0).)^ 2993** 2994** ^SQLite uses dynamic run-time typing. ^So just because a column 2995** is declared to contain a particular type does not mean that the 2996** data stored in that column is of the declared type. SQLite is 2997** strongly typed, but the typing is dynamic not static. ^Type 2998** is associated with individual values, not with the containers 2999** used to hold those values. 3000*/ 3001SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3002SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3003 3004/* 3005** CAPI3REF: Evaluate An SQL Statement 3006** 3007** After a [prepared statement] has been prepared using either 3008** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3009** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3010** must be called one or more times to evaluate the statement. 3011** 3012** The details of the behavior of the sqlite3_step() interface depend 3013** on whether the statement was prepared using the newer "v2" interface 3014** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3015** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3016** new "v2" interface is recommended for new applications but the legacy 3017** interface will continue to be supported. 3018** 3019** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3020** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3021** ^With the "v2" interface, any of the other [result codes] or 3022** [extended result codes] might be returned as well. 3023** 3024** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3025** database locks it needs to do its job. ^If the statement is a [COMMIT] 3026** or occurs outside of an explicit transaction, then you can retry the 3027** statement. If the statement is not a [COMMIT] and occurs within a 3028** explicit transaction then you should rollback the transaction before 3029** continuing. 3030** 3031** ^[SQLITE_DONE] means that the statement has finished executing 3032** successfully. sqlite3_step() should not be called again on this virtual 3033** machine without first calling [sqlite3_reset()] to reset the virtual 3034** machine back to its initial state. 3035** 3036** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3037** is returned each time a new row of data is ready for processing by the 3038** caller. The values may be accessed using the [column access functions]. 3039** sqlite3_step() is called again to retrieve the next row of data. 3040** 3041** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3042** violation) has occurred. sqlite3_step() should not be called again on 3043** the VM. More information may be found by calling [sqlite3_errmsg()]. 3044** ^With the legacy interface, a more specific error code (for example, 3045** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3046** can be obtained by calling [sqlite3_reset()] on the 3047** [prepared statement]. ^In the "v2" interface, 3048** the more specific error code is returned directly by sqlite3_step(). 3049** 3050** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3051** Perhaps it was called on a [prepared statement] that has 3052** already been [sqlite3_finalize | finalized] or on one that had 3053** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3054** be the case that the same database connection is being used by two or 3055** more threads at the same moment in time. 3056** 3057** For all versions of SQLite up to and including 3.6.23.1, it was required 3058** after sqlite3_step() returned anything other than [SQLITE_ROW] that 3059** [sqlite3_reset()] be called before any subsequent invocation of 3060** sqlite3_step(). Failure to invoke [sqlite3_reset()] in this way would 3061** result in an [SQLITE_MISUSE] return from sqlite3_step(). But after 3062** version 3.6.23.1, sqlite3_step() began calling [sqlite3_reset()] 3063** automatically in this circumstance rather than returning [SQLITE_MISUSE]. 3064** 3065** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3066** API always returns a generic error code, [SQLITE_ERROR], following any 3067** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3068** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3069** specific [error codes] that better describes the error. 3070** We admit that this is a goofy design. The problem has been fixed 3071** with the "v2" interface. If you prepare all of your SQL statements 3072** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3073** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3074** then the more specific [error codes] are returned directly 3075** by sqlite3_step(). The use of the "v2" interface is recommended. 3076*/ 3077SQLITE_API int sqlite3_step(sqlite3_stmt*); 3078 3079/* 3080** CAPI3REF: Number of columns in a result set 3081** 3082** ^The sqlite3_data_count(P) interface returns the number of columns in the 3083** current row of the result set of [prepared statement] P. 3084** ^If prepared statement P does not have results ready to return 3085** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3086** interfaces) then sqlite3_data_count(P) returns 0. 3087** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3088** 3089** See also: [sqlite3_column_count()] 3090*/ 3091SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); 3092 3093/* 3094** CAPI3REF: Fundamental Datatypes 3095** KEYWORDS: SQLITE_TEXT 3096** 3097** ^(Every value in SQLite has one of five fundamental datatypes: 3098** 3099** <ul> 3100** <li> 64-bit signed integer 3101** <li> 64-bit IEEE floating point number 3102** <li> string 3103** <li> BLOB 3104** <li> NULL 3105** </ul>)^ 3106** 3107** These constants are codes for each of those types. 3108** 3109** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3110** for a completely different meaning. Software that links against both 3111** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3112** SQLITE_TEXT. 3113*/ 3114#define SQLITE_INTEGER 1 3115#define SQLITE_FLOAT 2 3116#define SQLITE_BLOB 4 3117#define SQLITE_NULL 5 3118#ifdef SQLITE_TEXT 3119# undef SQLITE_TEXT 3120#else 3121# define SQLITE_TEXT 3 3122#endif 3123#define SQLITE3_TEXT 3 3124 3125/* 3126** CAPI3REF: Result Values From A Query 3127** KEYWORDS: {column access functions} 3128** 3129** These routines form the "result set" interface. 3130** 3131** ^These routines return information about a single column of the current 3132** result row of a query. ^In every case the first argument is a pointer 3133** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3134** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3135** and the second argument is the index of the column for which information 3136** should be returned. ^The leftmost column of the result set has the index 0. 3137** ^The number of columns in the result can be determined using 3138** [sqlite3_column_count()]. 3139** 3140** If the SQL statement does not currently point to a valid row, or if the 3141** column index is out of range, the result is undefined. 3142** These routines may only be called when the most recent call to 3143** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3144** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3145** If any of these routines are called after [sqlite3_reset()] or 3146** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3147** something other than [SQLITE_ROW], the results are undefined. 3148** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3149** are called from a different thread while any of these routines 3150** are pending, then the results are undefined. 3151** 3152** ^The sqlite3_column_type() routine returns the 3153** [SQLITE_INTEGER | datatype code] for the initial data type 3154** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3155** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3156** returned by sqlite3_column_type() is only meaningful if no type 3157** conversions have occurred as described below. After a type conversion, 3158** the value returned by sqlite3_column_type() is undefined. Future 3159** versions of SQLite may change the behavior of sqlite3_column_type() 3160** following a type conversion. 3161** 3162** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3163** routine returns the number of bytes in that BLOB or string. 3164** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3165** the string to UTF-8 and then returns the number of bytes. 3166** ^If the result is a numeric value then sqlite3_column_bytes() uses 3167** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3168** the number of bytes in that string. 3169** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3170** 3171** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3172** routine returns the number of bytes in that BLOB or string. 3173** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3174** the string to UTF-16 and then returns the number of bytes. 3175** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3176** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3177** the number of bytes in that string. 3178** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3179** 3180** ^The values returned by [sqlite3_column_bytes()] and 3181** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3182** of the string. ^For clarity: the values returned by 3183** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3184** bytes in the string, not the number of characters. 3185** 3186** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3187** even empty strings, are always zero terminated. ^The return 3188** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3189** 3190** ^The object returned by [sqlite3_column_value()] is an 3191** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3192** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3193** If the [unprotected sqlite3_value] object returned by 3194** [sqlite3_column_value()] is used in any other way, including calls 3195** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3196** or [sqlite3_value_bytes()], then the behavior is undefined. 3197** 3198** These routines attempt to convert the value where appropriate. ^For 3199** example, if the internal representation is FLOAT and a text result 3200** is requested, [sqlite3_snprintf()] is used internally to perform the 3201** conversion automatically. ^(The following table details the conversions 3202** that are applied: 3203** 3204** <blockquote> 3205** <table border="1"> 3206** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3207** 3208** <tr><td> NULL <td> INTEGER <td> Result is 0 3209** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3210** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3211** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3212** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3213** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3214** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3215** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3216** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3217** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3218** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3219** <tr><td> TEXT <td> FLOAT <td> Use atof() 3220** <tr><td> TEXT <td> BLOB <td> No change 3221** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3222** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3223** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3224** </table> 3225** </blockquote>)^ 3226** 3227** The table above makes reference to standard C library functions atoi() 3228** and atof(). SQLite does not really use these functions. It has its 3229** own equivalent internal routines. The atoi() and atof() names are 3230** used in the table for brevity and because they are familiar to most 3231** C programmers. 3232** 3233** Note that when type conversions occur, pointers returned by prior 3234** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3235** sqlite3_column_text16() may be invalidated. 3236** Type conversions and pointer invalidations might occur 3237** in the following cases: 3238** 3239** <ul> 3240** <li> The initial content is a BLOB and sqlite3_column_text() or 3241** sqlite3_column_text16() is called. A zero-terminator might 3242** need to be added to the string.</li> 3243** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3244** sqlite3_column_text16() is called. The content must be converted 3245** to UTF-16.</li> 3246** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3247** sqlite3_column_text() is called. The content must be converted 3248** to UTF-8.</li> 3249** </ul> 3250** 3251** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3252** not invalidate a prior pointer, though of course the content of the buffer 3253** that the prior pointer references will have been modified. Other kinds 3254** of conversion are done in place when it is possible, but sometimes they 3255** are not possible and in those cases prior pointers are invalidated. 3256** 3257** The safest and easiest to remember policy is to invoke these routines 3258** in one of the following ways: 3259** 3260** <ul> 3261** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3262** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3263** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3264** </ul> 3265** 3266** In other words, you should call sqlite3_column_text(), 3267** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3268** into the desired format, then invoke sqlite3_column_bytes() or 3269** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3270** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3271** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3272** with calls to sqlite3_column_bytes(). 3273** 3274** ^The pointers returned are valid until a type conversion occurs as 3275** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3276** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3277** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3278** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3279** [sqlite3_free()]. 3280** 3281** ^(If a memory allocation error occurs during the evaluation of any 3282** of these routines, a default value is returned. The default value 3283** is either the integer 0, the floating point number 0.0, or a NULL 3284** pointer. Subsequent calls to [sqlite3_errcode()] will return 3285** [SQLITE_NOMEM].)^ 3286*/ 3287SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3288SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3289SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3290SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); 3291SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); 3292SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3293SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3294SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3295SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); 3296SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3297 3298/* 3299** CAPI3REF: Destroy A Prepared Statement Object 3300** 3301** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3302** ^If the most recent evaluation of the statement encountered no errors or 3303** or if the statement is never been evaluated, then sqlite3_finalize() returns 3304** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3305** sqlite3_finalize(S) returns the appropriate [error code] or 3306** [extended error code]. 3307** 3308** ^The sqlite3_finalize(S) routine can be called at any point during 3309** the life cycle of [prepared statement] S: 3310** before statement S is ever evaluated, after 3311** one or more calls to [sqlite3_reset()], or after any call 3312** to [sqlite3_step()] regardless of whether or not the statement has 3313** completed execution. 3314** 3315** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3316** 3317** The application must finalize every [prepared statement] in order to avoid 3318** resource leaks. It is a grievous error for the application to try to use 3319** a prepared statement after it has been finalized. Any use of a prepared 3320** statement after it has been finalized can result in undefined and 3321** undesirable behavior such as segfaults and heap corruption. 3322*/ 3323SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); 3324 3325/* 3326** CAPI3REF: Reset A Prepared Statement Object 3327** 3328** The sqlite3_reset() function is called to reset a [prepared statement] 3329** object back to its initial state, ready to be re-executed. 3330** ^Any SQL statement variables that had values bound to them using 3331** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3332** Use [sqlite3_clear_bindings()] to reset the bindings. 3333** 3334** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3335** back to the beginning of its program. 3336** 3337** ^If the most recent call to [sqlite3_step(S)] for the 3338** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3339** or if [sqlite3_step(S)] has never before been called on S, 3340** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3341** 3342** ^If the most recent call to [sqlite3_step(S)] for the 3343** [prepared statement] S indicated an error, then 3344** [sqlite3_reset(S)] returns an appropriate [error code]. 3345** 3346** ^The [sqlite3_reset(S)] interface does not change the values 3347** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3348*/ 3349SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); 3350 3351/* 3352** CAPI3REF: Create Or Redefine SQL Functions 3353** KEYWORDS: {function creation routines} 3354** KEYWORDS: {application-defined SQL function} 3355** KEYWORDS: {application-defined SQL functions} 3356** 3357** ^These functions (collectively known as "function creation routines") 3358** are used to add SQL functions or aggregates or to redefine the behavior 3359** of existing SQL functions or aggregates. The only differences between 3360** these routines are the text encoding expected for 3361** the the second parameter (the name of the function being created) 3362** and the presence or absence of a destructor callback for 3363** the application data pointer. 3364** 3365** ^The first parameter is the [database connection] to which the SQL 3366** function is to be added. ^If an application uses more than one database 3367** connection then application-defined SQL functions must be added 3368** to each database connection separately. 3369** 3370** ^The second parameter is the name of the SQL function to be created or 3371** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3372** representation, exclusive of the zero-terminator. ^Note that the name 3373** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3374** ^Any attempt to create a function with a longer name 3375** will result in [SQLITE_MISUSE] being returned. 3376** 3377** ^The third parameter (nArg) 3378** is the number of arguments that the SQL function or 3379** aggregate takes. ^If this parameter is -1, then the SQL function or 3380** aggregate may take any number of arguments between 0 and the limit 3381** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3382** parameter is less than -1 or greater than 127 then the behavior is 3383** undefined. 3384** 3385** ^The fourth parameter, eTextRep, specifies what 3386** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3387** its parameters. Every SQL function implementation must be able to work 3388** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3389** more efficient with one encoding than another. ^An application may 3390** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3391** times with the same function but with different values of eTextRep. 3392** ^When multiple implementations of the same function are available, SQLite 3393** will pick the one that involves the least amount of data conversion. 3394** If there is only a single implementation which does not care what text 3395** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3396** 3397** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3398** function can gain access to this pointer using [sqlite3_user_data()].)^ 3399** 3400** ^The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3401** pointers to C-language functions that implement the SQL function or 3402** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3403** callback only; NULL pointers must be passed as the xStep and xFinal 3404** parameters. ^An aggregate SQL function requires an implementation of xStep 3405** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3406** SQL function or aggregate, pass NULL poiners for all three function 3407** callbacks. 3408** 3409** ^(If the tenth parameter to sqlite3_create_function_v2() is not NULL, 3410** then it is destructor for the application data pointer. 3411** The destructor is invoked when the function is deleted, either by being 3412** overloaded or when the database connection closes.)^ 3413** ^The destructor is also invoked if the call to 3414** sqlite3_create_function_v2() fails. 3415** ^When the destructor callback of the tenth parameter is invoked, it 3416** is passed a single argument which is a copy of the application data 3417** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3418** 3419** ^It is permitted to register multiple implementations of the same 3420** functions with the same name but with either differing numbers of 3421** arguments or differing preferred text encodings. ^SQLite will use 3422** the implementation that most closely matches the way in which the 3423** SQL function is used. ^A function implementation with a non-negative 3424** nArg parameter is a better match than a function implementation with 3425** a negative nArg. ^A function where the preferred text encoding 3426** matches the database encoding is a better 3427** match than a function where the encoding is different. 3428** ^A function where the encoding difference is between UTF16le and UTF16be 3429** is a closer match than a function where the encoding difference is 3430** between UTF8 and UTF16. 3431** 3432** ^Built-in functions may be overloaded by new application-defined functions. 3433** 3434** ^An application-defined function is permitted to call other 3435** SQLite interfaces. However, such calls must not 3436** close the database connection nor finalize or reset the prepared 3437** statement in which the function is running. 3438*/ 3439SQLITE_API int sqlite3_create_function( 3440 sqlite3 *db, 3441 const char *zFunctionName, 3442 int nArg, 3443 int eTextRep, 3444 void *pApp, 3445 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3446 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3447 void (*xFinal)(sqlite3_context*) 3448); 3449SQLITE_API int sqlite3_create_function16( 3450 sqlite3 *db, 3451 const void *zFunctionName, 3452 int nArg, 3453 int eTextRep, 3454 void *pApp, 3455 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3456 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3457 void (*xFinal)(sqlite3_context*) 3458); 3459SQLITE_API int sqlite3_create_function_v2( 3460 sqlite3 *db, 3461 const char *zFunctionName, 3462 int nArg, 3463 int eTextRep, 3464 void *pApp, 3465 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3466 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3467 void (*xFinal)(sqlite3_context*), 3468 void(*xDestroy)(void*) 3469); 3470 3471/* 3472** CAPI3REF: Text Encodings 3473** 3474** These constant define integer codes that represent the various 3475** text encodings supported by SQLite. 3476*/ 3477#define SQLITE_UTF8 1 3478#define SQLITE_UTF16LE 2 3479#define SQLITE_UTF16BE 3 3480#define SQLITE_UTF16 4 /* Use native byte order */ 3481#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3482#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3483 3484/* 3485** CAPI3REF: Deprecated Functions 3486** DEPRECATED 3487** 3488** These functions are [deprecated]. In order to maintain 3489** backwards compatibility with older code, these functions continue 3490** to be supported. However, new applications should avoid 3491** the use of these functions. To help encourage people to avoid 3492** using these functions, we are not going to tell you what they do. 3493*/ 3494#ifndef SQLITE_OMIT_DEPRECATED 3495SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3496SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3497SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3498SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); 3499SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3500SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3501#endif 3502 3503/* 3504** CAPI3REF: Obtaining SQL Function Parameter Values 3505** 3506** The C-language implementation of SQL functions and aggregates uses 3507** this set of interface routines to access the parameter values on 3508** the function or aggregate. 3509** 3510** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3511** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3512** define callbacks that implement the SQL functions and aggregates. 3513** The 4th parameter to these callbacks is an array of pointers to 3514** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3515** each parameter to the SQL function. These routines are used to 3516** extract values from the [sqlite3_value] objects. 3517** 3518** These routines work only with [protected sqlite3_value] objects. 3519** Any attempt to use these routines on an [unprotected sqlite3_value] 3520** object results in undefined behavior. 3521** 3522** ^These routines work just like the corresponding [column access functions] 3523** except that these routines take a single [protected sqlite3_value] object 3524** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3525** 3526** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3527** in the native byte-order of the host machine. ^The 3528** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3529** extract UTF-16 strings as big-endian and little-endian respectively. 3530** 3531** ^(The sqlite3_value_numeric_type() interface attempts to apply 3532** numeric affinity to the value. This means that an attempt is 3533** made to convert the value to an integer or floating point. If 3534** such a conversion is possible without loss of information (in other 3535** words, if the value is a string that looks like a number) 3536** then the conversion is performed. Otherwise no conversion occurs. 3537** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3538** 3539** Please pay particular attention to the fact that the pointer returned 3540** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3541** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3542** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3543** or [sqlite3_value_text16()]. 3544** 3545** These routines must be called from the same thread as 3546** the SQL function that supplied the [sqlite3_value*] parameters. 3547*/ 3548SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); 3549SQLITE_API int sqlite3_value_bytes(sqlite3_value*); 3550SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); 3551SQLITE_API double sqlite3_value_double(sqlite3_value*); 3552SQLITE_API int sqlite3_value_int(sqlite3_value*); 3553SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3554SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); 3555SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); 3556SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); 3557SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); 3558SQLITE_API int sqlite3_value_type(sqlite3_value*); 3559SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); 3560 3561/* 3562** CAPI3REF: Obtain Aggregate Function Context 3563** 3564** Implementations of aggregate SQL functions use this 3565** routine to allocate memory for storing their state. 3566** 3567** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3568** for a particular aggregate function, SQLite 3569** allocates N of memory, zeroes out that memory, and returns a pointer 3570** to the new memory. ^On second and subsequent calls to 3571** sqlite3_aggregate_context() for the same aggregate function instance, 3572** the same buffer is returned. Sqlite3_aggregate_context() is normally 3573** called once for each invocation of the xStep callback and then one 3574** last time when the xFinal callback is invoked. ^(When no rows match 3575** an aggregate query, the xStep() callback of the aggregate function 3576** implementation is never called and xFinal() is called exactly once. 3577** In those cases, sqlite3_aggregate_context() might be called for the 3578** first time from within xFinal().)^ 3579** 3580** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3581** less than or equal to zero or if a memory allocate error occurs. 3582** 3583** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3584** determined by the N parameter on first successful call. Changing the 3585** value of N in subsequent call to sqlite3_aggregate_context() within 3586** the same aggregate function instance will not resize the memory 3587** allocation.)^ 3588** 3589** ^SQLite automatically frees the memory allocated by 3590** sqlite3_aggregate_context() when the aggregate query concludes. 3591** 3592** The first parameter must be a copy of the 3593** [sqlite3_context | SQL function context] that is the first parameter 3594** to the xStep or xFinal callback routine that implements the aggregate 3595** function. 3596** 3597** This routine must be called from the same thread in which 3598** the aggregate SQL function is running. 3599*/ 3600SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3601 3602/* 3603** CAPI3REF: User Data For Functions 3604** 3605** ^The sqlite3_user_data() interface returns a copy of 3606** the pointer that was the pUserData parameter (the 5th parameter) 3607** of the [sqlite3_create_function()] 3608** and [sqlite3_create_function16()] routines that originally 3609** registered the application defined function. 3610** 3611** This routine must be called from the same thread in which 3612** the application-defined function is running. 3613*/ 3614SQLITE_API void *sqlite3_user_data(sqlite3_context*); 3615 3616/* 3617** CAPI3REF: Database Connection For Functions 3618** 3619** ^The sqlite3_context_db_handle() interface returns a copy of 3620** the pointer to the [database connection] (the 1st parameter) 3621** of the [sqlite3_create_function()] 3622** and [sqlite3_create_function16()] routines that originally 3623** registered the application defined function. 3624*/ 3625SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3626 3627/* 3628** CAPI3REF: Function Auxiliary Data 3629** 3630** The following two functions may be used by scalar SQL functions to 3631** associate metadata with argument values. If the same value is passed to 3632** multiple invocations of the same SQL function during query execution, under 3633** some circumstances the associated metadata may be preserved. This may 3634** be used, for example, to add a regular-expression matching scalar 3635** function. The compiled version of the regular expression is stored as 3636** metadata associated with the SQL value passed as the regular expression 3637** pattern. The compiled regular expression can be reused on multiple 3638** invocations of the same function so that the original pattern string 3639** does not need to be recompiled on each invocation. 3640** 3641** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 3642** associated by the sqlite3_set_auxdata() function with the Nth argument 3643** value to the application-defined function. ^If no metadata has been ever 3644** been set for the Nth argument of the function, or if the corresponding 3645** function parameter has changed since the meta-data was set, 3646** then sqlite3_get_auxdata() returns a NULL pointer. 3647** 3648** ^The sqlite3_set_auxdata() interface saves the metadata 3649** pointed to by its 3rd parameter as the metadata for the N-th 3650** argument of the application-defined function. Subsequent 3651** calls to sqlite3_get_auxdata() might return this data, if it has 3652** not been destroyed. 3653** ^If it is not NULL, SQLite will invoke the destructor 3654** function given by the 4th parameter to sqlite3_set_auxdata() on 3655** the metadata when the corresponding function parameter changes 3656** or when the SQL statement completes, whichever comes first. 3657** 3658** SQLite is free to call the destructor and drop metadata on any 3659** parameter of any function at any time. ^The only guarantee is that 3660** the destructor will be called before the metadata is dropped. 3661** 3662** ^(In practice, metadata is preserved between function calls for 3663** expressions that are constant at compile time. This includes literal 3664** values and [parameters].)^ 3665** 3666** These routines must be called from the same thread in which 3667** the SQL function is running. 3668*/ 3669SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); 3670SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3671 3672 3673/* 3674** CAPI3REF: Constants Defining Special Destructor Behavior 3675** 3676** These are special values for the destructor that is passed in as the 3677** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 3678** argument is SQLITE_STATIC, it means that the content pointer is constant 3679** and will never change. It does not need to be destroyed. ^The 3680** SQLITE_TRANSIENT value means that the content will likely change in 3681** the near future and that SQLite should make its own private copy of 3682** the content before returning. 3683** 3684** The typedef is necessary to work around problems in certain 3685** C++ compilers. See ticket #2191. 3686*/ 3687typedef void (*sqlite3_destructor_type)(void*); 3688#define SQLITE_STATIC ((sqlite3_destructor_type)0) 3689#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3690 3691/* 3692** CAPI3REF: Setting The Result Of An SQL Function 3693** 3694** These routines are used by the xFunc or xFinal callbacks that 3695** implement SQL functions and aggregates. See 3696** [sqlite3_create_function()] and [sqlite3_create_function16()] 3697** for additional information. 3698** 3699** These functions work very much like the [parameter binding] family of 3700** functions used to bind values to host parameters in prepared statements. 3701** Refer to the [SQL parameter] documentation for additional information. 3702** 3703** ^The sqlite3_result_blob() interface sets the result from 3704** an application-defined function to be the BLOB whose content is pointed 3705** to by the second parameter and which is N bytes long where N is the 3706** third parameter. 3707** 3708** ^The sqlite3_result_zeroblob() interfaces set the result of 3709** the application-defined function to be a BLOB containing all zero 3710** bytes and N bytes in size, where N is the value of the 2nd parameter. 3711** 3712** ^The sqlite3_result_double() interface sets the result from 3713** an application-defined function to be a floating point value specified 3714** by its 2nd argument. 3715** 3716** ^The sqlite3_result_error() and sqlite3_result_error16() functions 3717** cause the implemented SQL function to throw an exception. 3718** ^SQLite uses the string pointed to by the 3719** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3720** as the text of an error message. ^SQLite interprets the error 3721** message string from sqlite3_result_error() as UTF-8. ^SQLite 3722** interprets the string from sqlite3_result_error16() as UTF-16 in native 3723** byte order. ^If the third parameter to sqlite3_result_error() 3724** or sqlite3_result_error16() is negative then SQLite takes as the error 3725** message all text up through the first zero character. 3726** ^If the third parameter to sqlite3_result_error() or 3727** sqlite3_result_error16() is non-negative then SQLite takes that many 3728** bytes (not characters) from the 2nd parameter as the error message. 3729** ^The sqlite3_result_error() and sqlite3_result_error16() 3730** routines make a private copy of the error message text before 3731** they return. Hence, the calling function can deallocate or 3732** modify the text after they return without harm. 3733** ^The sqlite3_result_error_code() function changes the error code 3734** returned by SQLite as a result of an error in a function. ^By default, 3735** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 3736** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3737** 3738** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 3739** indicating that a string or BLOB is too long to represent. 3740** 3741** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 3742** indicating that a memory allocation failed. 3743** 3744** ^The sqlite3_result_int() interface sets the return value 3745** of the application-defined function to be the 32-bit signed integer 3746** value given in the 2nd argument. 3747** ^The sqlite3_result_int64() interface sets the return value 3748** of the application-defined function to be the 64-bit signed integer 3749** value given in the 2nd argument. 3750** 3751** ^The sqlite3_result_null() interface sets the return value 3752** of the application-defined function to be NULL. 3753** 3754** ^The sqlite3_result_text(), sqlite3_result_text16(), 3755** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3756** set the return value of the application-defined function to be 3757** a text string which is represented as UTF-8, UTF-16 native byte order, 3758** UTF-16 little endian, or UTF-16 big endian, respectively. 3759** ^SQLite takes the text result from the application from 3760** the 2nd parameter of the sqlite3_result_text* interfaces. 3761** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3762** is negative, then SQLite takes result text from the 2nd parameter 3763** through the first zero character. 3764** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3765** is non-negative, then as many bytes (not characters) of the text 3766** pointed to by the 2nd parameter are taken as the application-defined 3767** function result. 3768** ^If the 4th parameter to the sqlite3_result_text* interfaces 3769** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3770** function as the destructor on the text or BLOB result when it has 3771** finished using that result. 3772** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 3773** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3774** assumes that the text or BLOB result is in constant space and does not 3775** copy the content of the parameter nor call a destructor on the content 3776** when it has finished using that result. 3777** ^If the 4th parameter to the sqlite3_result_text* interfaces 3778** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3779** then SQLite makes a copy of the result into space obtained from 3780** from [sqlite3_malloc()] before it returns. 3781** 3782** ^The sqlite3_result_value() interface sets the result of 3783** the application-defined function to be a copy the 3784** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 3785** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3786** so that the [sqlite3_value] specified in the parameter may change or 3787** be deallocated after sqlite3_result_value() returns without harm. 3788** ^A [protected sqlite3_value] object may always be used where an 3789** [unprotected sqlite3_value] object is required, so either 3790** kind of [sqlite3_value] object can be used with this interface. 3791** 3792** If these routines are called from within the different thread 3793** than the one containing the application-defined function that received 3794** the [sqlite3_context] pointer, the results are undefined. 3795*/ 3796SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3797SQLITE_API void sqlite3_result_double(sqlite3_context*, double); 3798SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); 3799SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); 3800SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); 3801SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); 3802SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); 3803SQLITE_API void sqlite3_result_int(sqlite3_context*, int); 3804SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3805SQLITE_API void sqlite3_result_null(sqlite3_context*); 3806SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3807SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3808SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3809SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3810SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3811SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); 3812 3813/* 3814** CAPI3REF: Define New Collating Sequences 3815** 3816** ^These functions add, remove, or modify a [collation] associated 3817** with the [database connection] specified as the first argument. 3818** 3819** ^The name of the collation is a UTF-8 string 3820** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3821** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 3822** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 3823** considered to be the same name. 3824** 3825** ^(The third argument (eTextRep) must be one of the constants: 3826** <ul> 3827** <li> [SQLITE_UTF8], 3828** <li> [SQLITE_UTF16LE], 3829** <li> [SQLITE_UTF16BE], 3830** <li> [SQLITE_UTF16], or 3831** <li> [SQLITE_UTF16_ALIGNED]. 3832** </ul>)^ 3833** ^The eTextRep argument determines the encoding of strings passed 3834** to the collating function callback, xCallback. 3835** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 3836** force strings to be UTF16 with native byte order. 3837** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 3838** on an even byte address. 3839** 3840** ^The fourth argument, pArg, is a application data pointer that is passed 3841** through as the first argument to the collating function callback. 3842** 3843** ^The fifth argument, xCallback, is a pointer to the collating function. 3844** ^Multiple collating functions can be registered using the same name but 3845** with different eTextRep parameters and SQLite will use whichever 3846** function requires the least amount of data transformation. 3847** ^If the xCallback argument is NULL then the collating function is 3848** deleted. ^When all collating functions having the same name are deleted, 3849** that collation is no longer usable. 3850** 3851** ^The collating function callback is invoked with a copy of the pArg 3852** application data pointer and with two strings in the encoding specified 3853** by the eTextRep argument. The collating function must return an 3854** integer that is negative, zero, or positive 3855** if the first string is less than, equal to, or greater than the second, 3856** respectively. A collating function must alway return the same answer 3857** given the same inputs. If two or more collating functions are registered 3858** to the same collation name (using different eTextRep values) then all 3859** must give an equivalent answer when invoked with equivalent strings. 3860** The collating function must obey the following properties for all 3861** strings A, B, and C: 3862** 3863** <ol> 3864** <li> If A==B then B==A. 3865** <li> If A==B and B==C then A==C. 3866** <li> If A<B THEN B>A. 3867** <li> If A<B and B<C then A<C. 3868** </ol> 3869** 3870** If a collating function fails any of the above constraints and that 3871** collating function is registered and used, then the behavior of SQLite 3872** is undefined. 3873** 3874** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3875** with the addition that the xDestroy callback is invoked on pArg when 3876** the collating function is deleted. 3877** ^Collating functions are deleted when they are overridden by later 3878** calls to the collation creation functions or when the 3879** [database connection] is closed using [sqlite3_close()]. 3880** 3881** ^The xDestroy callback is <u>not</u> called if the 3882** sqlite3_create_collation_v2() function fails. Applications that invoke 3883** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 3884** check the return code and dispose of the application data pointer 3885** themselves rather than expecting SQLite to deal with it for them. 3886** This is different from every other SQLite interface. The inconsistency 3887** is unfortunate but cannot be changed without breaking backwards 3888** compatibility. 3889** 3890** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 3891*/ 3892SQLITE_API int sqlite3_create_collation( 3893 sqlite3*, 3894 const char *zName, 3895 int eTextRep, 3896 void *pArg, 3897 int(*xCompare)(void*,int,const void*,int,const void*) 3898); 3899SQLITE_API int sqlite3_create_collation_v2( 3900 sqlite3*, 3901 const char *zName, 3902 int eTextRep, 3903 void *pArg, 3904 int(*xCompare)(void*,int,const void*,int,const void*), 3905 void(*xDestroy)(void*) 3906); 3907SQLITE_API int sqlite3_create_collation16( 3908 sqlite3*, 3909 const void *zName, 3910 int eTextRep, 3911 void *pArg, 3912 int(*xCompare)(void*,int,const void*,int,const void*) 3913); 3914 3915/* 3916** CAPI3REF: Collation Needed Callbacks 3917** 3918** ^To avoid having to register all collation sequences before a database 3919** can be used, a single callback function may be registered with the 3920** [database connection] to be invoked whenever an undefined collation 3921** sequence is required. 3922** 3923** ^If the function is registered using the sqlite3_collation_needed() API, 3924** then it is passed the names of undefined collation sequences as strings 3925** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 3926** the names are passed as UTF-16 in machine native byte order. 3927** ^A call to either function replaces the existing collation-needed callback. 3928** 3929** ^(When the callback is invoked, the first argument passed is a copy 3930** of the second argument to sqlite3_collation_needed() or 3931** sqlite3_collation_needed16(). The second argument is the database 3932** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3933** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3934** sequence function required. The fourth parameter is the name of the 3935** required collation sequence.)^ 3936** 3937** The callback function should register the desired collation using 3938** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3939** [sqlite3_create_collation_v2()]. 3940*/ 3941SQLITE_API int sqlite3_collation_needed( 3942 sqlite3*, 3943 void*, 3944 void(*)(void*,sqlite3*,int eTextRep,const char*) 3945); 3946SQLITE_API int sqlite3_collation_needed16( 3947 sqlite3*, 3948 void*, 3949 void(*)(void*,sqlite3*,int eTextRep,const void*) 3950); 3951 3952#ifdef SQLITE_HAS_CODEC 3953/* 3954** Specify the key for an encrypted database. This routine should be 3955** called right after sqlite3_open(). 3956** 3957** The code to implement this API is not available in the public release 3958** of SQLite. 3959*/ 3960SQLITE_API int sqlite3_key( 3961 sqlite3 *db, /* Database to be rekeyed */ 3962 const void *pKey, int nKey /* The key */ 3963); 3964 3965/* 3966** Change the key on an open database. If the current database is not 3967** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3968** database is decrypted. 3969** 3970** The code to implement this API is not available in the public release 3971** of SQLite. 3972*/ 3973SQLITE_API int sqlite3_rekey( 3974 sqlite3 *db, /* Database to be rekeyed */ 3975 const void *pKey, int nKey /* The new key */ 3976); 3977 3978/* 3979** Specify the activation key for a SEE database. Unless 3980** activated, none of the SEE routines will work. 3981*/ 3982SQLITE_API void sqlite3_activate_see( 3983 const char *zPassPhrase /* Activation phrase */ 3984); 3985#endif 3986 3987#ifdef SQLITE_ENABLE_CEROD 3988/* 3989** Specify the activation key for a CEROD database. Unless 3990** activated, none of the CEROD routines will work. 3991*/ 3992SQLITE_API void sqlite3_activate_cerod( 3993 const char *zPassPhrase /* Activation phrase */ 3994); 3995#endif 3996 3997/* 3998** CAPI3REF: Suspend Execution For A Short Time 3999** 4000** The sqlite3_sleep() function causes the current thread to suspend execution 4001** for at least a number of milliseconds specified in its parameter. 4002** 4003** If the operating system does not support sleep requests with 4004** millisecond time resolution, then the time will be rounded up to 4005** the nearest second. The number of milliseconds of sleep actually 4006** requested from the operating system is returned. 4007** 4008** ^SQLite implements this interface by calling the xSleep() 4009** method of the default [sqlite3_vfs] object. If the xSleep() method 4010** of the default VFS is not implemented correctly, or not implemented at 4011** all, then the behavior of sqlite3_sleep() may deviate from the description 4012** in the previous paragraphs. 4013*/ 4014SQLITE_API int sqlite3_sleep(int); 4015 4016/* 4017** CAPI3REF: Name Of The Folder Holding Temporary Files 4018** 4019** ^(If this global variable is made to point to a string which is 4020** the name of a folder (a.k.a. directory), then all temporary files 4021** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4022** will be placed in that directory.)^ ^If this variable 4023** is a NULL pointer, then SQLite performs a search for an appropriate 4024** temporary file directory. 4025** 4026** It is not safe to read or modify this variable in more than one 4027** thread at a time. It is not safe to read or modify this variable 4028** if a [database connection] is being used at the same time in a separate 4029** thread. 4030** It is intended that this variable be set once 4031** as part of process initialization and before any SQLite interface 4032** routines have been called and that this variable remain unchanged 4033** thereafter. 4034** 4035** ^The [temp_store_directory pragma] may modify this variable and cause 4036** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4037** the [temp_store_directory pragma] always assumes that any string 4038** that this variable points to is held in memory obtained from 4039** [sqlite3_malloc] and the pragma may attempt to free that memory 4040** using [sqlite3_free]. 4041** Hence, if this variable is modified directly, either it should be 4042** made NULL or made to point to memory obtained from [sqlite3_malloc] 4043** or else the use of the [temp_store_directory pragma] should be avoided. 4044*/ 4045SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 4046 4047/* 4048** CAPI3REF: Test For Auto-Commit Mode 4049** KEYWORDS: {autocommit mode} 4050** 4051** ^The sqlite3_get_autocommit() interface returns non-zero or 4052** zero if the given database connection is or is not in autocommit mode, 4053** respectively. ^Autocommit mode is on by default. 4054** ^Autocommit mode is disabled by a [BEGIN] statement. 4055** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4056** 4057** If certain kinds of errors occur on a statement within a multi-statement 4058** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4059** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4060** transaction might be rolled back automatically. The only way to 4061** find out whether SQLite automatically rolled back the transaction after 4062** an error is to use this function. 4063** 4064** If another thread changes the autocommit status of the database 4065** connection while this routine is running, then the return value 4066** is undefined. 4067*/ 4068SQLITE_API int sqlite3_get_autocommit(sqlite3*); 4069 4070/* 4071** CAPI3REF: Find The Database Handle Of A Prepared Statement 4072** 4073** ^The sqlite3_db_handle interface returns the [database connection] handle 4074** to which a [prepared statement] belongs. ^The [database connection] 4075** returned by sqlite3_db_handle is the same [database connection] 4076** that was the first argument 4077** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4078** create the statement in the first place. 4079*/ 4080SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4081 4082/* 4083** CAPI3REF: Find the next prepared statement 4084** 4085** ^This interface returns a pointer to the next [prepared statement] after 4086** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4087** then this interface returns a pointer to the first prepared statement 4088** associated with the database connection pDb. ^If no prepared statement 4089** satisfies the conditions of this routine, it returns NULL. 4090** 4091** The [database connection] pointer D in a call to 4092** [sqlite3_next_stmt(D,S)] must refer to an open database 4093** connection and in particular must not be a NULL pointer. 4094*/ 4095SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4096 4097/* 4098** CAPI3REF: Commit And Rollback Notification Callbacks 4099** 4100** ^The sqlite3_commit_hook() interface registers a callback 4101** function to be invoked whenever a transaction is [COMMIT | committed]. 4102** ^Any callback set by a previous call to sqlite3_commit_hook() 4103** for the same database connection is overridden. 4104** ^The sqlite3_rollback_hook() interface registers a callback 4105** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4106** ^Any callback set by a previous call to sqlite3_rollback_hook() 4107** for the same database connection is overridden. 4108** ^The pArg argument is passed through to the callback. 4109** ^If the callback on a commit hook function returns non-zero, 4110** then the commit is converted into a rollback. 4111** 4112** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4113** return the P argument from the previous call of the same function 4114** on the same [database connection] D, or NULL for 4115** the first call for each function on D. 4116** 4117** The callback implementation must not do anything that will modify 4118** the database connection that invoked the callback. Any actions 4119** to modify the database connection must be deferred until after the 4120** completion of the [sqlite3_step()] call that triggered the commit 4121** or rollback hook in the first place. 4122** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4123** database connections for the meaning of "modify" in this paragraph. 4124** 4125** ^Registering a NULL function disables the callback. 4126** 4127** ^When the commit hook callback routine returns zero, the [COMMIT] 4128** operation is allowed to continue normally. ^If the commit hook 4129** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4130** ^The rollback hook is invoked on a rollback that results from a commit 4131** hook returning non-zero, just as it would be with any other rollback. 4132** 4133** ^For the purposes of this API, a transaction is said to have been 4134** rolled back if an explicit "ROLLBACK" statement is executed, or 4135** an error or constraint causes an implicit rollback to occur. 4136** ^The rollback callback is not invoked if a transaction is 4137** automatically rolled back because the database connection is closed. 4138** 4139** See also the [sqlite3_update_hook()] interface. 4140*/ 4141SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4142SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4143 4144/* 4145** CAPI3REF: Data Change Notification Callbacks 4146** 4147** ^The sqlite3_update_hook() interface registers a callback function 4148** with the [database connection] identified by the first argument 4149** to be invoked whenever a row is updated, inserted or deleted. 4150** ^Any callback set by a previous call to this function 4151** for the same database connection is overridden. 4152** 4153** ^The second argument is a pointer to the function to invoke when a 4154** row is updated, inserted or deleted. 4155** ^The first argument to the callback is a copy of the third argument 4156** to sqlite3_update_hook(). 4157** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4158** or [SQLITE_UPDATE], depending on the operation that caused the callback 4159** to be invoked. 4160** ^The third and fourth arguments to the callback contain pointers to the 4161** database and table name containing the affected row. 4162** ^The final callback parameter is the [rowid] of the row. 4163** ^In the case of an update, this is the [rowid] after the update takes place. 4164** 4165** ^(The update hook is not invoked when internal system tables are 4166** modified (i.e. sqlite_master and sqlite_sequence).)^ 4167** 4168** ^In the current implementation, the update hook 4169** is not invoked when duplication rows are deleted because of an 4170** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4171** invoked when rows are deleted using the [truncate optimization]. 4172** The exceptions defined in this paragraph might change in a future 4173** release of SQLite. 4174** 4175** The update hook implementation must not do anything that will modify 4176** the database connection that invoked the update hook. Any actions 4177** to modify the database connection must be deferred until after the 4178** completion of the [sqlite3_step()] call that triggered the update hook. 4179** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4180** database connections for the meaning of "modify" in this paragraph. 4181** 4182** ^The sqlite3_update_hook(D,C,P) function 4183** returns the P argument from the previous call 4184** on the same [database connection] D, or NULL for 4185** the first call on D. 4186** 4187** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4188** interfaces. 4189*/ 4190SQLITE_API void *sqlite3_update_hook( 4191 sqlite3*, 4192 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4193 void* 4194); 4195 4196/* 4197** CAPI3REF: Enable Or Disable Shared Pager Cache 4198** KEYWORDS: {shared cache} 4199** 4200** ^(This routine enables or disables the sharing of the database cache 4201** and schema data structures between [database connection | connections] 4202** to the same database. Sharing is enabled if the argument is true 4203** and disabled if the argument is false.)^ 4204** 4205** ^Cache sharing is enabled and disabled for an entire process. 4206** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4207** sharing was enabled or disabled for each thread separately. 4208** 4209** ^(The cache sharing mode set by this interface effects all subsequent 4210** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4211** Existing database connections continue use the sharing mode 4212** that was in effect at the time they were opened.)^ 4213** 4214** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4215** successfully. An [error code] is returned otherwise.)^ 4216** 4217** ^Shared cache is disabled by default. But this might change in 4218** future releases of SQLite. Applications that care about shared 4219** cache setting should set it explicitly. 4220** 4221** See Also: [SQLite Shared-Cache Mode] 4222*/ 4223SQLITE_API int sqlite3_enable_shared_cache(int); 4224 4225/* 4226** CAPI3REF: Attempt To Free Heap Memory 4227** 4228** ^The sqlite3_release_memory() interface attempts to free N bytes 4229** of heap memory by deallocating non-essential memory allocations 4230** held by the database library. Memory used to cache database 4231** pages to improve performance is an example of non-essential memory. 4232** ^sqlite3_release_memory() returns the number of bytes actually freed, 4233** which might be more or less than the amount requested. 4234** ^The sqlite3_release_memory() routine is a no-op returning zero 4235** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4236*/ 4237SQLITE_API int sqlite3_release_memory(int); 4238 4239/* 4240** CAPI3REF: Impose A Limit On Heap Size 4241** 4242** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4243** soft limit on the amount of heap memory that may be allocated by SQLite. 4244** ^SQLite strives to keep heap memory utilization below the soft heap 4245** limit by reducing the number of pages held in the page cache 4246** as heap memory usages approaches the limit. 4247** ^The soft heap limit is "soft" because even though SQLite strives to stay 4248** below the limit, it will exceed the limit rather than generate 4249** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4250** is advisory only. 4251** 4252** ^The return value from sqlite3_soft_heap_limit64() is the size of 4253** the soft heap limit prior to the call. ^If the argument N is negative 4254** then no change is made to the soft heap limit. Hence, the current 4255** size of the soft heap limit can be determined by invoking 4256** sqlite3_soft_heap_limit64() with a negative argument. 4257** 4258** ^If the argument N is zero then the soft heap limit is disabled. 4259** 4260** ^(The soft heap limit is not enforced in the current implementation 4261** if one or more of following conditions are true: 4262** 4263** <ul> 4264** <li> The soft heap limit is set to zero. 4265** <li> Memory accounting is disabled using a combination of the 4266** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4267** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4268** <li> An alternative page cache implementation is specifed using 4269** [sqlite3_config]([SQLITE_CONFIG_PCACHE],...). 4270** <li> The page cache allocates from its own memory pool supplied 4271** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4272** from the heap. 4273** </ul>)^ 4274** 4275** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4276** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4277** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4278** the soft heap limit is enforced on every memory allocation. Without 4279** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4280** when memory is allocated by the page cache. Testing suggests that because 4281** the page cache is the predominate memory user in SQLite, most 4282** applications will achieve adequate soft heap limit enforcement without 4283** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4284** 4285** The circumstances under which SQLite will enforce the soft heap limit may 4286** changes in future releases of SQLite. 4287*/ 4288SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4289 4290/* 4291** CAPI3REF: Deprecated Soft Heap Limit Interface 4292** DEPRECATED 4293** 4294** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4295** interface. This routine is provided for historical compatibility 4296** only. All new applications should use the 4297** [sqlite3_soft_heap_limit64()] interface rather than this one. 4298*/ 4299SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4300 4301 4302/* 4303** CAPI3REF: Extract Metadata About A Column Of A Table 4304** 4305** ^This routine returns metadata about a specific column of a specific 4306** database table accessible using the [database connection] handle 4307** passed as the first function argument. 4308** 4309** ^The column is identified by the second, third and fourth parameters to 4310** this function. ^The second parameter is either the name of the database 4311** (i.e. "main", "temp", or an attached database) containing the specified 4312** table or NULL. ^If it is NULL, then all attached databases are searched 4313** for the table using the same algorithm used by the database engine to 4314** resolve unqualified table references. 4315** 4316** ^The third and fourth parameters to this function are the table and column 4317** name of the desired column, respectively. Neither of these parameters 4318** may be NULL. 4319** 4320** ^Metadata is returned by writing to the memory locations passed as the 5th 4321** and subsequent parameters to this function. ^Any of these arguments may be 4322** NULL, in which case the corresponding element of metadata is omitted. 4323** 4324** ^(<blockquote> 4325** <table border="1"> 4326** <tr><th> Parameter <th> Output<br>Type <th> Description 4327** 4328** <tr><td> 5th <td> const char* <td> Data type 4329** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4330** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4331** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4332** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4333** </table> 4334** </blockquote>)^ 4335** 4336** ^The memory pointed to by the character pointers returned for the 4337** declaration type and collation sequence is valid only until the next 4338** call to any SQLite API function. 4339** 4340** ^If the specified table is actually a view, an [error code] is returned. 4341** 4342** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4343** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4344** parameters are set for the explicitly declared column. ^(If there is no 4345** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4346** parameters are set as follows: 4347** 4348** <pre> 4349** data type: "INTEGER" 4350** collation sequence: "BINARY" 4351** not null: 0 4352** primary key: 1 4353** auto increment: 0 4354** </pre>)^ 4355** 4356** ^(This function may load one or more schemas from database files. If an 4357** error occurs during this process, or if the requested table or column 4358** cannot be found, an [error code] is returned and an error message left 4359** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4360** 4361** ^This API is only available if the library was compiled with the 4362** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4363*/ 4364SQLITE_API int sqlite3_table_column_metadata( 4365 sqlite3 *db, /* Connection handle */ 4366 const char *zDbName, /* Database name or NULL */ 4367 const char *zTableName, /* Table name */ 4368 const char *zColumnName, /* Column name */ 4369 char const **pzDataType, /* OUTPUT: Declared data type */ 4370 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4371 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4372 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4373 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4374); 4375 4376/* 4377** CAPI3REF: Load An Extension 4378** 4379** ^This interface loads an SQLite extension library from the named file. 4380** 4381** ^The sqlite3_load_extension() interface attempts to load an 4382** SQLite extension library contained in the file zFile. 4383** 4384** ^The entry point is zProc. 4385** ^zProc may be 0, in which case the name of the entry point 4386** defaults to "sqlite3_extension_init". 4387** ^The sqlite3_load_extension() interface returns 4388** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4389** ^If an error occurs and pzErrMsg is not 0, then the 4390** [sqlite3_load_extension()] interface shall attempt to 4391** fill *pzErrMsg with error message text stored in memory 4392** obtained from [sqlite3_malloc()]. The calling function 4393** should free this memory by calling [sqlite3_free()]. 4394** 4395** ^Extension loading must be enabled using 4396** [sqlite3_enable_load_extension()] prior to calling this API, 4397** otherwise an error will be returned. 4398** 4399** See also the [load_extension() SQL function]. 4400*/ 4401SQLITE_API int sqlite3_load_extension( 4402 sqlite3 *db, /* Load the extension into this database connection */ 4403 const char *zFile, /* Name of the shared library containing extension */ 4404 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4405 char **pzErrMsg /* Put error message here if not 0 */ 4406); 4407 4408/* 4409** CAPI3REF: Enable Or Disable Extension Loading 4410** 4411** ^So as not to open security holes in older applications that are 4412** unprepared to deal with extension loading, and as a means of disabling 4413** extension loading while evaluating user-entered SQL, the following API 4414** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4415** 4416** ^Extension loading is off by default. See ticket #1863. 4417** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4418** to turn extension loading on and call it with onoff==0 to turn 4419** it back off again. 4420*/ 4421SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4422 4423/* 4424** CAPI3REF: Automatically Load Statically Linked Extensions 4425** 4426** ^This interface causes the xEntryPoint() function to be invoked for 4427** each new [database connection] that is created. The idea here is that 4428** xEntryPoint() is the entry point for a statically linked SQLite extension 4429** that is to be automatically loaded into all new database connections. 4430** 4431** ^(Even though the function prototype shows that xEntryPoint() takes 4432** no arguments and returns void, SQLite invokes xEntryPoint() with three 4433** arguments and expects and integer result as if the signature of the 4434** entry point where as follows: 4435** 4436** <blockquote><pre> 4437** int xEntryPoint( 4438** sqlite3 *db, 4439** const char **pzErrMsg, 4440** const struct sqlite3_api_routines *pThunk 4441** ); 4442** </pre></blockquote>)^ 4443** 4444** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 4445** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 4446** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 4447** is NULL before calling the xEntryPoint(). ^SQLite will invoke 4448** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 4449** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 4450** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 4451** 4452** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 4453** on the list of automatic extensions is a harmless no-op. ^No entry point 4454** will be called more than once for each database connection that is opened. 4455** 4456** See also: [sqlite3_reset_auto_extension()]. 4457*/ 4458SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4459 4460/* 4461** CAPI3REF: Reset Automatic Extension Loading 4462** 4463** ^This interface disables all automatic extensions previously 4464** registered using [sqlite3_auto_extension()]. 4465*/ 4466SQLITE_API void sqlite3_reset_auto_extension(void); 4467 4468/* 4469** The interface to the virtual-table mechanism is currently considered 4470** to be experimental. The interface might change in incompatible ways. 4471** If this is a problem for you, do not use the interface at this time. 4472** 4473** When the virtual-table mechanism stabilizes, we will declare the 4474** interface fixed, support it indefinitely, and remove this comment. 4475*/ 4476 4477/* 4478** Structures used by the virtual table interface 4479*/ 4480typedef struct sqlite3_vtab sqlite3_vtab; 4481typedef struct sqlite3_index_info sqlite3_index_info; 4482typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4483typedef struct sqlite3_module sqlite3_module; 4484 4485/* 4486** CAPI3REF: Virtual Table Object 4487** KEYWORDS: sqlite3_module {virtual table module} 4488** 4489** This structure, sometimes called a a "virtual table module", 4490** defines the implementation of a [virtual tables]. 4491** This structure consists mostly of methods for the module. 4492** 4493** ^A virtual table module is created by filling in a persistent 4494** instance of this structure and passing a pointer to that instance 4495** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4496** ^The registration remains valid until it is replaced by a different 4497** module or until the [database connection] closes. The content 4498** of this structure must not change while it is registered with 4499** any database connection. 4500*/ 4501struct sqlite3_module { 4502 int iVersion; 4503 int (*xCreate)(sqlite3*, void *pAux, 4504 int argc, const char *const*argv, 4505 sqlite3_vtab **ppVTab, char**); 4506 int (*xConnect)(sqlite3*, void *pAux, 4507 int argc, const char *const*argv, 4508 sqlite3_vtab **ppVTab, char**); 4509 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4510 int (*xDisconnect)(sqlite3_vtab *pVTab); 4511 int (*xDestroy)(sqlite3_vtab *pVTab); 4512 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4513 int (*xClose)(sqlite3_vtab_cursor*); 4514 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4515 int argc, sqlite3_value **argv); 4516 int (*xNext)(sqlite3_vtab_cursor*); 4517 int (*xEof)(sqlite3_vtab_cursor*); 4518 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4519 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4520 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4521 int (*xBegin)(sqlite3_vtab *pVTab); 4522 int (*xSync)(sqlite3_vtab *pVTab); 4523 int (*xCommit)(sqlite3_vtab *pVTab); 4524 int (*xRollback)(sqlite3_vtab *pVTab); 4525 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4526 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4527 void **ppArg); 4528 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4529}; 4530 4531/* 4532** CAPI3REF: Virtual Table Indexing Information 4533** KEYWORDS: sqlite3_index_info 4534** 4535** The sqlite3_index_info structure and its substructures is used as part 4536** of the [virtual table] interface to 4537** pass information into and receive the reply from the [xBestIndex] 4538** method of a [virtual table module]. The fields under **Inputs** are the 4539** inputs to xBestIndex and are read-only. xBestIndex inserts its 4540** results into the **Outputs** fields. 4541** 4542** ^(The aConstraint[] array records WHERE clause constraints of the form: 4543** 4544** <blockquote>column OP expr</blockquote> 4545** 4546** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4547** stored in aConstraint[].op using one of the 4548** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 4549** ^(The index of the column is stored in 4550** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4551** expr on the right-hand side can be evaluated (and thus the constraint 4552** is usable) and false if it cannot.)^ 4553** 4554** ^The optimizer automatically inverts terms of the form "expr OP column" 4555** and makes other simplifications to the WHERE clause in an attempt to 4556** get as many WHERE clause terms into the form shown above as possible. 4557** ^The aConstraint[] array only reports WHERE clause terms that are 4558** relevant to the particular virtual table being queried. 4559** 4560** ^Information about the ORDER BY clause is stored in aOrderBy[]. 4561** ^Each term of aOrderBy records a column of the ORDER BY clause. 4562** 4563** The [xBestIndex] method must fill aConstraintUsage[] with information 4564** about what parameters to pass to xFilter. ^If argvIndex>0 then 4565** the right-hand side of the corresponding aConstraint[] is evaluated 4566** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 4567** is true, then the constraint is assumed to be fully handled by the 4568** virtual table and is not checked again by SQLite.)^ 4569** 4570** ^The idxNum and idxPtr values are recorded and passed into the 4571** [xFilter] method. 4572** ^[sqlite3_free()] is used to free idxPtr if and only if 4573** needToFreeIdxPtr is true. 4574** 4575** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4576** the correct order to satisfy the ORDER BY clause so that no separate 4577** sorting step is required. 4578** 4579** ^The estimatedCost value is an estimate of the cost of doing the 4580** particular lookup. A full scan of a table with N entries should have 4581** a cost of N. A binary search of a table of N entries should have a 4582** cost of approximately log(N). 4583*/ 4584struct sqlite3_index_info { 4585 /* Inputs */ 4586 int nConstraint; /* Number of entries in aConstraint */ 4587 struct sqlite3_index_constraint { 4588 int iColumn; /* Column on left-hand side of constraint */ 4589 unsigned char op; /* Constraint operator */ 4590 unsigned char usable; /* True if this constraint is usable */ 4591 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4592 } *aConstraint; /* Table of WHERE clause constraints */ 4593 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4594 struct sqlite3_index_orderby { 4595 int iColumn; /* Column number */ 4596 unsigned char desc; /* True for DESC. False for ASC. */ 4597 } *aOrderBy; /* The ORDER BY clause */ 4598 /* Outputs */ 4599 struct sqlite3_index_constraint_usage { 4600 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4601 unsigned char omit; /* Do not code a test for this constraint */ 4602 } *aConstraintUsage; 4603 int idxNum; /* Number used to identify the index */ 4604 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4605 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4606 int orderByConsumed; /* True if output is already ordered */ 4607 double estimatedCost; /* Estimated cost of using this index */ 4608}; 4609 4610/* 4611** CAPI3REF: Virtual Table Constraint Operator Codes 4612** 4613** These macros defined the allowed values for the 4614** [sqlite3_index_info].aConstraint[].op field. Each value represents 4615** an operator that is part of a constraint term in the wHERE clause of 4616** a query that uses a [virtual table]. 4617*/ 4618#define SQLITE_INDEX_CONSTRAINT_EQ 2 4619#define SQLITE_INDEX_CONSTRAINT_GT 4 4620#define SQLITE_INDEX_CONSTRAINT_LE 8 4621#define SQLITE_INDEX_CONSTRAINT_LT 16 4622#define SQLITE_INDEX_CONSTRAINT_GE 32 4623#define SQLITE_INDEX_CONSTRAINT_MATCH 64 4624 4625/* 4626** CAPI3REF: Register A Virtual Table Implementation 4627** 4628** ^These routines are used to register a new [virtual table module] name. 4629** ^Module names must be registered before 4630** creating a new [virtual table] using the module and before using a 4631** preexisting [virtual table] for the module. 4632** 4633** ^The module name is registered on the [database connection] specified 4634** by the first parameter. ^The name of the module is given by the 4635** second parameter. ^The third parameter is a pointer to 4636** the implementation of the [virtual table module]. ^The fourth 4637** parameter is an arbitrary client data pointer that is passed through 4638** into the [xCreate] and [xConnect] methods of the virtual table module 4639** when a new virtual table is be being created or reinitialized. 4640** 4641** ^The sqlite3_create_module_v2() interface has a fifth parameter which 4642** is a pointer to a destructor for the pClientData. ^SQLite will 4643** invoke the destructor function (if it is not NULL) when SQLite 4644** no longer needs the pClientData pointer. ^The destructor will also 4645** be invoked if the call to sqlite3_create_module_v2() fails. 4646** ^The sqlite3_create_module() 4647** interface is equivalent to sqlite3_create_module_v2() with a NULL 4648** destructor. 4649*/ 4650SQLITE_API int sqlite3_create_module( 4651 sqlite3 *db, /* SQLite connection to register module with */ 4652 const char *zName, /* Name of the module */ 4653 const sqlite3_module *p, /* Methods for the module */ 4654 void *pClientData /* Client data for xCreate/xConnect */ 4655); 4656SQLITE_API int sqlite3_create_module_v2( 4657 sqlite3 *db, /* SQLite connection to register module with */ 4658 const char *zName, /* Name of the module */ 4659 const sqlite3_module *p, /* Methods for the module */ 4660 void *pClientData, /* Client data for xCreate/xConnect */ 4661 void(*xDestroy)(void*) /* Module destructor function */ 4662); 4663 4664/* 4665** CAPI3REF: Virtual Table Instance Object 4666** KEYWORDS: sqlite3_vtab 4667** 4668** Every [virtual table module] implementation uses a subclass 4669** of this object to describe a particular instance 4670** of the [virtual table]. Each subclass will 4671** be tailored to the specific needs of the module implementation. 4672** The purpose of this superclass is to define certain fields that are 4673** common to all module implementations. 4674** 4675** ^Virtual tables methods can set an error message by assigning a 4676** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4677** take care that any prior string is freed by a call to [sqlite3_free()] 4678** prior to assigning a new string to zErrMsg. ^After the error message 4679** is delivered up to the client application, the string will be automatically 4680** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4681*/ 4682struct sqlite3_vtab { 4683 const sqlite3_module *pModule; /* The module for this virtual table */ 4684 int nRef; /* NO LONGER USED */ 4685 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4686 /* Virtual table implementations will typically add additional fields */ 4687}; 4688 4689/* 4690** CAPI3REF: Virtual Table Cursor Object 4691** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4692** 4693** Every [virtual table module] implementation uses a subclass of the 4694** following structure to describe cursors that point into the 4695** [virtual table] and are used 4696** to loop through the virtual table. Cursors are created using the 4697** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4698** by the [sqlite3_module.xClose | xClose] method. Cursors are used 4699** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4700** of the module. Each module implementation will define 4701** the content of a cursor structure to suit its own needs. 4702** 4703** This superclass exists in order to define fields of the cursor that 4704** are common to all implementations. 4705*/ 4706struct sqlite3_vtab_cursor { 4707 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4708 /* Virtual table implementations will typically add additional fields */ 4709}; 4710 4711/* 4712** CAPI3REF: Declare The Schema Of A Virtual Table 4713** 4714** ^The [xCreate] and [xConnect] methods of a 4715** [virtual table module] call this interface 4716** to declare the format (the names and datatypes of the columns) of 4717** the virtual tables they implement. 4718*/ 4719SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4720 4721/* 4722** CAPI3REF: Overload A Function For A Virtual Table 4723** 4724** ^(Virtual tables can provide alternative implementations of functions 4725** using the [xFindFunction] method of the [virtual table module]. 4726** But global versions of those functions 4727** must exist in order to be overloaded.)^ 4728** 4729** ^(This API makes sure a global version of a function with a particular 4730** name and number of parameters exists. If no such function exists 4731** before this API is called, a new function is created.)^ ^The implementation 4732** of the new function always causes an exception to be thrown. So 4733** the new function is not good for anything by itself. Its only 4734** purpose is to be a placeholder function that can be overloaded 4735** by a [virtual table]. 4736*/ 4737SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4738 4739/* 4740** The interface to the virtual-table mechanism defined above (back up 4741** to a comment remarkably similar to this one) is currently considered 4742** to be experimental. The interface might change in incompatible ways. 4743** If this is a problem for you, do not use the interface at this time. 4744** 4745** When the virtual-table mechanism stabilizes, we will declare the 4746** interface fixed, support it indefinitely, and remove this comment. 4747*/ 4748 4749/* 4750** CAPI3REF: A Handle To An Open BLOB 4751** KEYWORDS: {BLOB handle} {BLOB handles} 4752** 4753** An instance of this object represents an open BLOB on which 4754** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4755** ^Objects of this type are created by [sqlite3_blob_open()] 4756** and destroyed by [sqlite3_blob_close()]. 4757** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4758** can be used to read or write small subsections of the BLOB. 4759** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4760*/ 4761typedef struct sqlite3_blob sqlite3_blob; 4762 4763/* 4764** CAPI3REF: Open A BLOB For Incremental I/O 4765** 4766** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 4767** in row iRow, column zColumn, table zTable in database zDb; 4768** in other words, the same BLOB that would be selected by: 4769** 4770** <pre> 4771** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4772** </pre>)^ 4773** 4774** ^If the flags parameter is non-zero, then the BLOB is opened for read 4775** and write access. ^If it is zero, the BLOB is opened for read access. 4776** ^It is not possible to open a column that is part of an index or primary 4777** key for writing. ^If [foreign key constraints] are enabled, it is 4778** not possible to open a column that is part of a [child key] for writing. 4779** 4780** ^Note that the database name is not the filename that contains 4781** the database but rather the symbolic name of the database that 4782** appears after the AS keyword when the database is connected using [ATTACH]. 4783** ^For the main database file, the database name is "main". 4784** ^For TEMP tables, the database name is "temp". 4785** 4786** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4787** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 4788** to be a null pointer.)^ 4789** ^This function sets the [database connection] error code and message 4790** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 4791** functions. ^Note that the *ppBlob variable is always initialized in a 4792** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 4793** regardless of the success or failure of this routine. 4794** 4795** ^(If the row that a BLOB handle points to is modified by an 4796** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4797** then the BLOB handle is marked as "expired". 4798** This is true if any column of the row is changed, even a column 4799** other than the one the BLOB handle is open on.)^ 4800** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4801** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4802** ^(Changes written into a BLOB prior to the BLOB expiring are not 4803** rolled back by the expiration of the BLOB. Such changes will eventually 4804** commit if the transaction continues to completion.)^ 4805** 4806** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 4807** the opened blob. ^The size of a blob may not be changed by this 4808** interface. Use the [UPDATE] SQL command to change the size of a 4809** blob. 4810** 4811** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 4812** and the built-in [zeroblob] SQL function can be used, if desired, 4813** to create an empty, zero-filled blob in which to read or write using 4814** this interface. 4815** 4816** To avoid a resource leak, every open [BLOB handle] should eventually 4817** be released by a call to [sqlite3_blob_close()]. 4818*/ 4819SQLITE_API int sqlite3_blob_open( 4820 sqlite3*, 4821 const char *zDb, 4822 const char *zTable, 4823 const char *zColumn, 4824 sqlite3_int64 iRow, 4825 int flags, 4826 sqlite3_blob **ppBlob 4827); 4828 4829/* 4830** CAPI3REF: Move a BLOB Handle to a New Row 4831** 4832** ^This function is used to move an existing blob handle so that it points 4833** to a different row of the same database table. ^The new row is identified 4834** by the rowid value passed as the second argument. Only the row can be 4835** changed. ^The database, table and column on which the blob handle is open 4836** remain the same. Moving an existing blob handle to a new row can be 4837** faster than closing the existing handle and opening a new one. 4838** 4839** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 4840** it must exist and there must be either a blob or text value stored in 4841** the nominated column.)^ ^If the new row is not present in the table, or if 4842** it does not contain a blob or text value, or if another error occurs, an 4843** SQLite error code is returned and the blob handle is considered aborted. 4844** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 4845** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 4846** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 4847** always returns zero. 4848** 4849** ^This function sets the database handle error code and message. 4850*/ 4851SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 4852 4853/* 4854** CAPI3REF: Close A BLOB Handle 4855** 4856** ^Closes an open [BLOB handle]. 4857** 4858** ^Closing a BLOB shall cause the current transaction to commit 4859** if there are no other BLOBs, no pending prepared statements, and the 4860** database connection is in [autocommit mode]. 4861** ^If any writes were made to the BLOB, they might be held in cache 4862** until the close operation if they will fit. 4863** 4864** ^(Closing the BLOB often forces the changes 4865** out to disk and so if any I/O errors occur, they will likely occur 4866** at the time when the BLOB is closed. Any errors that occur during 4867** closing are reported as a non-zero return value.)^ 4868** 4869** ^(The BLOB is closed unconditionally. Even if this routine returns 4870** an error code, the BLOB is still closed.)^ 4871** 4872** ^Calling this routine with a null pointer (such as would be returned 4873** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 4874*/ 4875SQLITE_API int sqlite3_blob_close(sqlite3_blob *); 4876 4877/* 4878** CAPI3REF: Return The Size Of An Open BLOB 4879** 4880** ^Returns the size in bytes of the BLOB accessible via the 4881** successfully opened [BLOB handle] in its only argument. ^The 4882** incremental blob I/O routines can only read or overwriting existing 4883** blob content; they cannot change the size of a blob. 4884** 4885** This routine only works on a [BLOB handle] which has been created 4886** by a prior successful call to [sqlite3_blob_open()] and which has not 4887** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4888** to this routine results in undefined and probably undesirable behavior. 4889*/ 4890SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); 4891 4892/* 4893** CAPI3REF: Read Data From A BLOB Incrementally 4894** 4895** ^(This function is used to read data from an open [BLOB handle] into a 4896** caller-supplied buffer. N bytes of data are copied into buffer Z 4897** from the open BLOB, starting at offset iOffset.)^ 4898** 4899** ^If offset iOffset is less than N bytes from the end of the BLOB, 4900** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 4901** less than zero, [SQLITE_ERROR] is returned and no data is read. 4902** ^The size of the blob (and hence the maximum value of N+iOffset) 4903** can be determined using the [sqlite3_blob_bytes()] interface. 4904** 4905** ^An attempt to read from an expired [BLOB handle] fails with an 4906** error code of [SQLITE_ABORT]. 4907** 4908** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 4909** Otherwise, an [error code] or an [extended error code] is returned.)^ 4910** 4911** This routine only works on a [BLOB handle] which has been created 4912** by a prior successful call to [sqlite3_blob_open()] and which has not 4913** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4914** to this routine results in undefined and probably undesirable behavior. 4915** 4916** See also: [sqlite3_blob_write()]. 4917*/ 4918SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4919 4920/* 4921** CAPI3REF: Write Data Into A BLOB Incrementally 4922** 4923** ^This function is used to write data into an open [BLOB handle] from a 4924** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 4925** into the open BLOB, starting at offset iOffset. 4926** 4927** ^If the [BLOB handle] passed as the first argument was not opened for 4928** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4929** this function returns [SQLITE_READONLY]. 4930** 4931** ^This function may only modify the contents of the BLOB; it is 4932** not possible to increase the size of a BLOB using this API. 4933** ^If offset iOffset is less than N bytes from the end of the BLOB, 4934** [SQLITE_ERROR] is returned and no data is written. ^If N is 4935** less than zero [SQLITE_ERROR] is returned and no data is written. 4936** The size of the BLOB (and hence the maximum value of N+iOffset) 4937** can be determined using the [sqlite3_blob_bytes()] interface. 4938** 4939** ^An attempt to write to an expired [BLOB handle] fails with an 4940** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 4941** before the [BLOB handle] expired are not rolled back by the 4942** expiration of the handle, though of course those changes might 4943** have been overwritten by the statement that expired the BLOB handle 4944** or by other independent statements. 4945** 4946** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 4947** Otherwise, an [error code] or an [extended error code] is returned.)^ 4948** 4949** This routine only works on a [BLOB handle] which has been created 4950** by a prior successful call to [sqlite3_blob_open()] and which has not 4951** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4952** to this routine results in undefined and probably undesirable behavior. 4953** 4954** See also: [sqlite3_blob_read()]. 4955*/ 4956SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4957 4958/* 4959** CAPI3REF: Virtual File System Objects 4960** 4961** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4962** that SQLite uses to interact 4963** with the underlying operating system. Most SQLite builds come with a 4964** single default VFS that is appropriate for the host computer. 4965** New VFSes can be registered and existing VFSes can be unregistered. 4966** The following interfaces are provided. 4967** 4968** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4969** ^Names are case sensitive. 4970** ^Names are zero-terminated UTF-8 strings. 4971** ^If there is no match, a NULL pointer is returned. 4972** ^If zVfsName is NULL then the default VFS is returned. 4973** 4974** ^New VFSes are registered with sqlite3_vfs_register(). 4975** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 4976** ^The same VFS can be registered multiple times without injury. 4977** ^To make an existing VFS into the default VFS, register it again 4978** with the makeDflt flag set. If two different VFSes with the 4979** same name are registered, the behavior is undefined. If a 4980** VFS is registered with a name that is NULL or an empty string, 4981** then the behavior is undefined. 4982** 4983** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 4984** ^(If the default VFS is unregistered, another VFS is chosen as 4985** the default. The choice for the new VFS is arbitrary.)^ 4986*/ 4987SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4988SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4989SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); 4990 4991/* 4992** CAPI3REF: Mutexes 4993** 4994** The SQLite core uses these routines for thread 4995** synchronization. Though they are intended for internal 4996** use by SQLite, code that links against SQLite is 4997** permitted to use any of these routines. 4998** 4999** The SQLite source code contains multiple implementations 5000** of these mutex routines. An appropriate implementation 5001** is selected automatically at compile-time. ^(The following 5002** implementations are available in the SQLite core: 5003** 5004** <ul> 5005** <li> SQLITE_MUTEX_OS2 5006** <li> SQLITE_MUTEX_PTHREAD 5007** <li> SQLITE_MUTEX_W32 5008** <li> SQLITE_MUTEX_NOOP 5009** </ul>)^ 5010** 5011** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5012** that does no real locking and is appropriate for use in 5013** a single-threaded application. ^The SQLITE_MUTEX_OS2, 5014** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 5015** are appropriate for use on OS/2, Unix, and Windows. 5016** 5017** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5018** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5019** implementation is included with the library. In this case the 5020** application must supply a custom mutex implementation using the 5021** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5022** before calling sqlite3_initialize() or any other public sqlite3_ 5023** function that calls sqlite3_initialize().)^ 5024** 5025** ^The sqlite3_mutex_alloc() routine allocates a new 5026** mutex and returns a pointer to it. ^If it returns NULL 5027** that means that a mutex could not be allocated. ^SQLite 5028** will unwind its stack and return an error. ^(The argument 5029** to sqlite3_mutex_alloc() is one of these integer constants: 5030** 5031** <ul> 5032** <li> SQLITE_MUTEX_FAST 5033** <li> SQLITE_MUTEX_RECURSIVE 5034** <li> SQLITE_MUTEX_STATIC_MASTER 5035** <li> SQLITE_MUTEX_STATIC_MEM 5036** <li> SQLITE_MUTEX_STATIC_MEM2 5037** <li> SQLITE_MUTEX_STATIC_PRNG 5038** <li> SQLITE_MUTEX_STATIC_LRU 5039** <li> SQLITE_MUTEX_STATIC_LRU2 5040** </ul>)^ 5041** 5042** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5043** cause sqlite3_mutex_alloc() to create 5044** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5045** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5046** The mutex implementation does not need to make a distinction 5047** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5048** not want to. ^SQLite will only request a recursive mutex in 5049** cases where it really needs one. ^If a faster non-recursive mutex 5050** implementation is available on the host platform, the mutex subsystem 5051** might return such a mutex in response to SQLITE_MUTEX_FAST. 5052** 5053** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5054** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5055** a pointer to a static preexisting mutex. ^Six static mutexes are 5056** used by the current version of SQLite. Future versions of SQLite 5057** may add additional static mutexes. Static mutexes are for internal 5058** use by SQLite only. Applications that use SQLite mutexes should 5059** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5060** SQLITE_MUTEX_RECURSIVE. 5061** 5062** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5063** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5064** returns a different mutex on every call. ^But for the static 5065** mutex types, the same mutex is returned on every call that has 5066** the same type number. 5067** 5068** ^The sqlite3_mutex_free() routine deallocates a previously 5069** allocated dynamic mutex. ^SQLite is careful to deallocate every 5070** dynamic mutex that it allocates. The dynamic mutexes must not be in 5071** use when they are deallocated. Attempting to deallocate a static 5072** mutex results in undefined behavior. ^SQLite never deallocates 5073** a static mutex. 5074** 5075** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5076** to enter a mutex. ^If another thread is already within the mutex, 5077** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5078** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5079** upon successful entry. ^(Mutexes created using 5080** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5081** In such cases the, 5082** mutex must be exited an equal number of times before another thread 5083** can enter.)^ ^(If the same thread tries to enter any other 5084** kind of mutex more than once, the behavior is undefined. 5085** SQLite will never exhibit 5086** such behavior in its own use of mutexes.)^ 5087** 5088** ^(Some systems (for example, Windows 95) do not support the operation 5089** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5090** will always return SQLITE_BUSY. The SQLite core only ever uses 5091** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5092** 5093** ^The sqlite3_mutex_leave() routine exits a mutex that was 5094** previously entered by the same thread. ^(The behavior 5095** is undefined if the mutex is not currently entered by the 5096** calling thread or is not currently allocated. SQLite will 5097** never do either.)^ 5098** 5099** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5100** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5101** behave as no-ops. 5102** 5103** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5104*/ 5105SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); 5106SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); 5107SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); 5108SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); 5109SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); 5110 5111/* 5112** CAPI3REF: Mutex Methods Object 5113** 5114** An instance of this structure defines the low-level routines 5115** used to allocate and use mutexes. 5116** 5117** Usually, the default mutex implementations provided by SQLite are 5118** sufficient, however the user has the option of substituting a custom 5119** implementation for specialized deployments or systems for which SQLite 5120** does not provide a suitable implementation. In this case, the user 5121** creates and populates an instance of this structure to pass 5122** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5123** Additionally, an instance of this structure can be used as an 5124** output variable when querying the system for the current mutex 5125** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5126** 5127** ^The xMutexInit method defined by this structure is invoked as 5128** part of system initialization by the sqlite3_initialize() function. 5129** ^The xMutexInit routine is called by SQLite exactly once for each 5130** effective call to [sqlite3_initialize()]. 5131** 5132** ^The xMutexEnd method defined by this structure is invoked as 5133** part of system shutdown by the sqlite3_shutdown() function. The 5134** implementation of this method is expected to release all outstanding 5135** resources obtained by the mutex methods implementation, especially 5136** those obtained by the xMutexInit method. ^The xMutexEnd() 5137** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5138** 5139** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5140** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5141** xMutexNotheld) implement the following interfaces (respectively): 5142** 5143** <ul> 5144** <li> [sqlite3_mutex_alloc()] </li> 5145** <li> [sqlite3_mutex_free()] </li> 5146** <li> [sqlite3_mutex_enter()] </li> 5147** <li> [sqlite3_mutex_try()] </li> 5148** <li> [sqlite3_mutex_leave()] </li> 5149** <li> [sqlite3_mutex_held()] </li> 5150** <li> [sqlite3_mutex_notheld()] </li> 5151** </ul>)^ 5152** 5153** The only difference is that the public sqlite3_XXX functions enumerated 5154** above silently ignore any invocations that pass a NULL pointer instead 5155** of a valid mutex handle. The implementations of the methods defined 5156** by this structure are not required to handle this case, the results 5157** of passing a NULL pointer instead of a valid mutex handle are undefined 5158** (i.e. it is acceptable to provide an implementation that segfaults if 5159** it is passed a NULL pointer). 5160** 5161** The xMutexInit() method must be threadsafe. ^It must be harmless to 5162** invoke xMutexInit() multiple times within the same process and without 5163** intervening calls to xMutexEnd(). Second and subsequent calls to 5164** xMutexInit() must be no-ops. 5165** 5166** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5167** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5168** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5169** memory allocation for a fast or recursive mutex. 5170** 5171** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5172** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5173** If xMutexInit fails in any way, it is expected to clean up after itself 5174** prior to returning. 5175*/ 5176typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5177struct sqlite3_mutex_methods { 5178 int (*xMutexInit)(void); 5179 int (*xMutexEnd)(void); 5180 sqlite3_mutex *(*xMutexAlloc)(int); 5181 void (*xMutexFree)(sqlite3_mutex *); 5182 void (*xMutexEnter)(sqlite3_mutex *); 5183 int (*xMutexTry)(sqlite3_mutex *); 5184 void (*xMutexLeave)(sqlite3_mutex *); 5185 int (*xMutexHeld)(sqlite3_mutex *); 5186 int (*xMutexNotheld)(sqlite3_mutex *); 5187}; 5188 5189/* 5190** CAPI3REF: Mutex Verification Routines 5191** 5192** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5193** are intended for use inside assert() statements. ^The SQLite core 5194** never uses these routines except inside an assert() and applications 5195** are advised to follow the lead of the core. ^The SQLite core only 5196** provides implementations for these routines when it is compiled 5197** with the SQLITE_DEBUG flag. ^External mutex implementations 5198** are only required to provide these routines if SQLITE_DEBUG is 5199** defined and if NDEBUG is not defined. 5200** 5201** ^These routines should return true if the mutex in their argument 5202** is held or not held, respectively, by the calling thread. 5203** 5204** ^The implementation is not required to provided versions of these 5205** routines that actually work. If the implementation does not provide working 5206** versions of these routines, it should at least provide stubs that always 5207** return true so that one does not get spurious assertion failures. 5208** 5209** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5210** the routine should return 1. This seems counter-intuitive since 5211** clearly the mutex cannot be held if it does not exist. But the 5212** the reason the mutex does not exist is because the build is not 5213** using mutexes. And we do not want the assert() containing the 5214** call to sqlite3_mutex_held() to fail, so a non-zero return is 5215** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5216** interface should also return 1 when given a NULL pointer. 5217*/ 5218#ifndef NDEBUG 5219SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); 5220SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); 5221#endif 5222 5223/* 5224** CAPI3REF: Mutex Types 5225** 5226** The [sqlite3_mutex_alloc()] interface takes a single argument 5227** which is one of these integer constants. 5228** 5229** The set of static mutexes may change from one SQLite release to the 5230** next. Applications that override the built-in mutex logic must be 5231** prepared to accommodate additional static mutexes. 5232*/ 5233#define SQLITE_MUTEX_FAST 0 5234#define SQLITE_MUTEX_RECURSIVE 1 5235#define SQLITE_MUTEX_STATIC_MASTER 2 5236#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5237#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5238#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5239#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5240#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5241#define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 5242 5243/* 5244** CAPI3REF: Retrieve the mutex for a database connection 5245** 5246** ^This interface returns a pointer the [sqlite3_mutex] object that 5247** serializes access to the [database connection] given in the argument 5248** when the [threading mode] is Serialized. 5249** ^If the [threading mode] is Single-thread or Multi-thread then this 5250** routine returns a NULL pointer. 5251*/ 5252SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5253 5254/* 5255** CAPI3REF: Low-Level Control Of Database Files 5256** 5257** ^The [sqlite3_file_control()] interface makes a direct call to the 5258** xFileControl method for the [sqlite3_io_methods] object associated 5259** with a particular database identified by the second argument. ^The 5260** name of the database is "main" for the main database or "temp" for the 5261** TEMP database, or the name that appears after the AS keyword for 5262** databases that are added using the [ATTACH] SQL command. 5263** ^A NULL pointer can be used in place of "main" to refer to the 5264** main database file. 5265** ^The third and fourth parameters to this routine 5266** are passed directly through to the second and third parameters of 5267** the xFileControl method. ^The return value of the xFileControl 5268** method becomes the return value of this routine. 5269** 5270** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5271** a pointer to the underlying [sqlite3_file] object to be written into 5272** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5273** case is a short-circuit path which does not actually invoke the 5274** underlying sqlite3_io_methods.xFileControl method. 5275** 5276** ^If the second parameter (zDbName) does not match the name of any 5277** open database file, then SQLITE_ERROR is returned. ^This error 5278** code is not remembered and will not be recalled by [sqlite3_errcode()] 5279** or [sqlite3_errmsg()]. The underlying xFileControl method might 5280** also return SQLITE_ERROR. There is no way to distinguish between 5281** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5282** xFileControl method. 5283** 5284** See also: [SQLITE_FCNTL_LOCKSTATE] 5285*/ 5286SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5287 5288/* 5289** CAPI3REF: Testing Interface 5290** 5291** ^The sqlite3_test_control() interface is used to read out internal 5292** state of SQLite and to inject faults into SQLite for testing 5293** purposes. ^The first parameter is an operation code that determines 5294** the number, meaning, and operation of all subsequent parameters. 5295** 5296** This interface is not for use by applications. It exists solely 5297** for verifying the correct operation of the SQLite library. Depending 5298** on how the SQLite library is compiled, this interface might not exist. 5299** 5300** The details of the operation codes, their meanings, the parameters 5301** they take, and what they do are all subject to change without notice. 5302** Unlike most of the SQLite API, this function is not guaranteed to 5303** operate consistently from one release to the next. 5304*/ 5305SQLITE_API int sqlite3_test_control(int op, ...); 5306 5307/* 5308** CAPI3REF: Testing Interface Operation Codes 5309** 5310** These constants are the valid operation code parameters used 5311** as the first argument to [sqlite3_test_control()]. 5312** 5313** These parameters and their meanings are subject to change 5314** without notice. These values are for testing purposes only. 5315** Applications should not use any of these parameters or the 5316** [sqlite3_test_control()] interface. 5317*/ 5318#define SQLITE_TESTCTRL_FIRST 5 5319#define SQLITE_TESTCTRL_PRNG_SAVE 5 5320#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5321#define SQLITE_TESTCTRL_PRNG_RESET 7 5322#define SQLITE_TESTCTRL_BITVEC_TEST 8 5323#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5324#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5325#define SQLITE_TESTCTRL_PENDING_BYTE 11 5326#define SQLITE_TESTCTRL_ASSERT 12 5327#define SQLITE_TESTCTRL_ALWAYS 13 5328#define SQLITE_TESTCTRL_RESERVE 14 5329#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5330#define SQLITE_TESTCTRL_ISKEYWORD 16 5331#define SQLITE_TESTCTRL_PGHDRSZ 17 5332#define SQLITE_TESTCTRL_SCRATCHMALLOC 18 5333#define SQLITE_TESTCTRL_LAST 18 5334 5335/* 5336** CAPI3REF: SQLite Runtime Status 5337** 5338** ^This interface is used to retrieve runtime status information 5339** about the performance of SQLite, and optionally to reset various 5340** highwater marks. ^The first argument is an integer code for 5341** the specific parameter to measure. ^(Recognized integer codes 5342** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^ 5343** ^The current value of the parameter is returned into *pCurrent. 5344** ^The highest recorded value is returned in *pHighwater. ^If the 5345** resetFlag is true, then the highest record value is reset after 5346** *pHighwater is written. ^(Some parameters do not record the highest 5347** value. For those parameters 5348** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5349** ^(Other parameters record only the highwater mark and not the current 5350** value. For these latter parameters nothing is written into *pCurrent.)^ 5351** 5352** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5353** non-zero [error code] on failure. 5354** 5355** This routine is threadsafe but is not atomic. This routine can be 5356** called while other threads are running the same or different SQLite 5357** interfaces. However the values returned in *pCurrent and 5358** *pHighwater reflect the status of SQLite at different points in time 5359** and it is possible that another thread might change the parameter 5360** in between the times when *pCurrent and *pHighwater are written. 5361** 5362** See also: [sqlite3_db_status()] 5363*/ 5364SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5365 5366 5367/* 5368** CAPI3REF: Status Parameters 5369** 5370** These integer constants designate various run-time status parameters 5371** that can be returned by [sqlite3_status()]. 5372** 5373** <dl> 5374** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5375** <dd>This parameter is the current amount of memory checked out 5376** using [sqlite3_malloc()], either directly or indirectly. The 5377** figure includes calls made to [sqlite3_malloc()] by the application 5378** and internal memory usage by the SQLite library. Scratch memory 5379** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5380** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5381** this parameter. The amount returned is the sum of the allocation 5382** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5383** 5384** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5385** <dd>This parameter records the largest memory allocation request 5386** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5387** internal equivalents). Only the value returned in the 5388** *pHighwater parameter to [sqlite3_status()] is of interest. 5389** The value written into the *pCurrent parameter is undefined.</dd>)^ 5390** 5391** ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5392** <dd>This parameter records the number of separate memory allocations.</dd>)^ 5393** 5394** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5395** <dd>This parameter returns the number of pages used out of the 5396** [pagecache memory allocator] that was configured using 5397** [SQLITE_CONFIG_PAGECACHE]. The 5398** value returned is in pages, not in bytes.</dd>)^ 5399** 5400** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5401** <dd>This parameter returns the number of bytes of page cache 5402** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 5403** buffer and where forced to overflow to [sqlite3_malloc()]. The 5404** returned value includes allocations that overflowed because they 5405** where too large (they were larger than the "sz" parameter to 5406** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5407** no space was left in the page cache.</dd>)^ 5408** 5409** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5410** <dd>This parameter records the largest memory allocation request 5411** handed to [pagecache memory allocator]. Only the value returned in the 5412** *pHighwater parameter to [sqlite3_status()] is of interest. 5413** The value written into the *pCurrent parameter is undefined.</dd>)^ 5414** 5415** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5416** <dd>This parameter returns the number of allocations used out of the 5417** [scratch memory allocator] configured using 5418** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5419** in bytes. Since a single thread may only have one scratch allocation 5420** outstanding at time, this parameter also reports the number of threads 5421** using scratch memory at the same time.</dd>)^ 5422** 5423** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5424** <dd>This parameter returns the number of bytes of scratch memory 5425** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 5426** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5427** returned include overflows because the requested allocation was too 5428** larger (that is, because the requested allocation was larger than the 5429** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5430** slots were available. 5431** </dd>)^ 5432** 5433** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5434** <dd>This parameter records the largest memory allocation request 5435** handed to [scratch memory allocator]. Only the value returned in the 5436** *pHighwater parameter to [sqlite3_status()] is of interest. 5437** The value written into the *pCurrent parameter is undefined.</dd>)^ 5438** 5439** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5440** <dd>This parameter records the deepest parser stack. It is only 5441** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5442** </dl> 5443** 5444** New status parameters may be added from time to time. 5445*/ 5446#define SQLITE_STATUS_MEMORY_USED 0 5447#define SQLITE_STATUS_PAGECACHE_USED 1 5448#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5449#define SQLITE_STATUS_SCRATCH_USED 3 5450#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5451#define SQLITE_STATUS_MALLOC_SIZE 5 5452#define SQLITE_STATUS_PARSER_STACK 6 5453#define SQLITE_STATUS_PAGECACHE_SIZE 7 5454#define SQLITE_STATUS_SCRATCH_SIZE 8 5455#define SQLITE_STATUS_MALLOC_COUNT 9 5456 5457/* 5458** CAPI3REF: Database Connection Status 5459** 5460** ^This interface is used to retrieve runtime status information 5461** about a single [database connection]. ^The first argument is the 5462** database connection object to be interrogated. ^The second argument 5463** is an integer constant, taken from the set of 5464** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros, that 5465** determines the parameter to interrogate. The set of 5466** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros is likely 5467** to grow in future releases of SQLite. 5468** 5469** ^The current value of the requested parameter is written into *pCur 5470** and the highest instantaneous value is written into *pHiwtr. ^If 5471** the resetFlg is true, then the highest instantaneous value is 5472** reset back down to the current value. 5473** 5474** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5475** non-zero [error code] on failure. 5476** 5477** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5478*/ 5479SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5480 5481/* 5482** CAPI3REF: Status Parameters for database connections 5483** 5484** These constants are the available integer "verbs" that can be passed as 5485** the second argument to the [sqlite3_db_status()] interface. 5486** 5487** New verbs may be added in future releases of SQLite. Existing verbs 5488** might be discontinued. Applications should check the return code from 5489** [sqlite3_db_status()] to make sure that the call worked. 5490** The [sqlite3_db_status()] interface will return a non-zero error code 5491** if a discontinued or unsupported verb is invoked. 5492** 5493** <dl> 5494** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5495** <dd>This parameter returns the number of lookaside memory slots currently 5496** checked out.</dd>)^ 5497** 5498** ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5499** <dd>This parameter returns the approximate number of of bytes of heap 5500** memory used by all pager caches associated with the database connection.)^ 5501** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5502** 5503** ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5504** <dd>This parameter returns the approximate number of of bytes of heap 5505** memory used to store the schema for all databases associated 5506** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5507** ^The full amount of memory used by the schemas is reported, even if the 5508** schema memory is shared with other database connections due to 5509** [shared cache mode] being enabled. 5510** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5511** 5512** ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5513** <dd>This parameter returns the approximate number of of bytes of heap 5514** and lookaside memory used by all prepared statements associated with 5515** the database connection.)^ 5516** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5517** </dd> 5518** </dl> 5519*/ 5520#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5521#define SQLITE_DBSTATUS_CACHE_USED 1 5522#define SQLITE_DBSTATUS_SCHEMA_USED 2 5523#define SQLITE_DBSTATUS_STMT_USED 3 5524#define SQLITE_DBSTATUS_MAX 3 /* Largest defined DBSTATUS */ 5525 5526 5527/* 5528** CAPI3REF: Prepared Statement Status 5529** 5530** ^(Each prepared statement maintains various 5531** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 5532** of times it has performed specific operations.)^ These counters can 5533** be used to monitor the performance characteristics of the prepared 5534** statements. For example, if the number of table steps greatly exceeds 5535** the number of table searches or result rows, that would tend to indicate 5536** that the prepared statement is using a full table scan rather than 5537** an index. 5538** 5539** ^(This interface is used to retrieve and reset counter values from 5540** a [prepared statement]. The first argument is the prepared statement 5541** object to be interrogated. The second argument 5542** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 5543** to be interrogated.)^ 5544** ^The current value of the requested counter is returned. 5545** ^If the resetFlg is true, then the counter is reset to zero after this 5546** interface call returns. 5547** 5548** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5549*/ 5550SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5551 5552/* 5553** CAPI3REF: Status Parameters for prepared statements 5554** 5555** These preprocessor macros define integer codes that name counter 5556** values associated with the [sqlite3_stmt_status()] interface. 5557** The meanings of the various counters are as follows: 5558** 5559** <dl> 5560** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5561** <dd>^This is the number of times that SQLite has stepped forward in 5562** a table as part of a full table scan. Large numbers for this counter 5563** may indicate opportunities for performance improvement through 5564** careful use of indices.</dd> 5565** 5566** <dt>SQLITE_STMTSTATUS_SORT</dt> 5567** <dd>^This is the number of sort operations that have occurred. 5568** A non-zero value in this counter may indicate an opportunity to 5569** improvement performance through careful use of indices.</dd> 5570** 5571** <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 5572** <dd>^This is the number of rows inserted into transient indices that 5573** were created automatically in order to help joins run faster. 5574** A non-zero value in this counter may indicate an opportunity to 5575** improvement performance by adding permanent indices that do not 5576** need to be reinitialized each time the statement is run.</dd> 5577** 5578** </dl> 5579*/ 5580#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5581#define SQLITE_STMTSTATUS_SORT 2 5582#define SQLITE_STMTSTATUS_AUTOINDEX 3 5583 5584/* 5585** CAPI3REF: Custom Page Cache Object 5586** 5587** The sqlite3_pcache type is opaque. It is implemented by 5588** the pluggable module. The SQLite core has no knowledge of 5589** its size or internal structure and never deals with the 5590** sqlite3_pcache object except by holding and passing pointers 5591** to the object. 5592** 5593** See [sqlite3_pcache_methods] for additional information. 5594*/ 5595typedef struct sqlite3_pcache sqlite3_pcache; 5596 5597/* 5598** CAPI3REF: Application Defined Page Cache. 5599** KEYWORDS: {page cache} 5600** 5601** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5602** register an alternative page cache implementation by passing in an 5603** instance of the sqlite3_pcache_methods structure.)^ 5604** In many applications, most of the heap memory allocated by 5605** SQLite is used for the page cache. 5606** By implementing a 5607** custom page cache using this API, an application can better control 5608** the amount of memory consumed by SQLite, the way in which 5609** that memory is allocated and released, and the policies used to 5610** determine exactly which parts of a database file are cached and for 5611** how long. 5612** 5613** The alternative page cache mechanism is an 5614** extreme measure that is only needed by the most demanding applications. 5615** The built-in page cache is recommended for most uses. 5616** 5617** ^(The contents of the sqlite3_pcache_methods structure are copied to an 5618** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5619** the application may discard the parameter after the call to 5620** [sqlite3_config()] returns.)^ 5621** 5622** ^(The xInit() method is called once for each effective 5623** call to [sqlite3_initialize()])^ 5624** (usually only once during the lifetime of the process). ^(The xInit() 5625** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ 5626** The intent of the xInit() method is to set up global data structures 5627** required by the custom page cache implementation. 5628** ^(If the xInit() method is NULL, then the 5629** built-in default page cache is used instead of the application defined 5630** page cache.)^ 5631** 5632** ^The xShutdown() method is called by [sqlite3_shutdown()]. 5633** It can be used to clean up 5634** any outstanding resources before process shutdown, if required. 5635** ^The xShutdown() method may be NULL. 5636** 5637** ^SQLite automatically serializes calls to the xInit method, 5638** so the xInit method need not be threadsafe. ^The 5639** xShutdown method is only called from [sqlite3_shutdown()] so it does 5640** not need to be threadsafe either. All other methods must be threadsafe 5641** in multithreaded applications. 5642** 5643** ^SQLite will never invoke xInit() more than once without an intervening 5644** call to xShutdown(). 5645** 5646** ^SQLite invokes the xCreate() method to construct a new cache instance. 5647** SQLite will typically create one cache instance for each open database file, 5648** though this is not guaranteed. ^The 5649** first parameter, szPage, is the size in bytes of the pages that must 5650** be allocated by the cache. ^szPage will not be a power of two. ^szPage 5651** will the page size of the database file that is to be cached plus an 5652** increment (here called "R") of about 100 or 200. SQLite will use the 5653** extra R bytes on each page to store metadata about the underlying 5654** database page on disk. The value of R depends 5655** on the SQLite version, the target platform, and how SQLite was compiled. 5656** ^R is constant for a particular build of SQLite. ^The second argument to 5657** xCreate(), bPurgeable, is true if the cache being created will 5658** be used to cache database pages of a file stored on disk, or 5659** false if it is used for an in-memory database. The cache implementation 5660** does not have to do anything special based with the value of bPurgeable; 5661** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 5662** never invoke xUnpin() except to deliberately delete a page. 5663** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 5664** false will always have the "discard" flag set to true. 5665** ^Hence, a cache created with bPurgeable false will 5666** never contain any unpinned pages. 5667** 5668** ^(The xCachesize() method may be called at any time by SQLite to set the 5669** suggested maximum cache-size (number of pages stored by) the cache 5670** instance passed as the first argument. This is the value configured using 5671** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 5672** parameter, the implementation is not required to do anything with this 5673** value; it is advisory only. 5674** 5675** The xPagecount() method must return the number of pages currently 5676** stored in the cache, both pinned and unpinned. 5677** 5678** The xFetch() method locates a page in the cache and returns a pointer to 5679** the page, or a NULL pointer. 5680** A "page", in this context, means a buffer of szPage bytes aligned at an 5681** 8-byte boundary. The page to be fetched is determined by the key. ^The 5682** mimimum key value is 1. After it has been retrieved using xFetch, the page 5683** is considered to be "pinned". 5684** 5685** If the requested page is already in the page cache, then the page cache 5686** implementation must return a pointer to the page buffer with its content 5687** intact. If the requested page is not already in the cache, then the 5688** behavior of the cache implementation should use the value of the createFlag 5689** parameter to help it determined what action to take: 5690** 5691** <table border=1 width=85% align=center> 5692** <tr><th> createFlag <th> Behaviour when page is not already in cache 5693** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 5694** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 5695** Otherwise return NULL. 5696** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 5697** NULL if allocating a new page is effectively impossible. 5698** </table> 5699** 5700** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 5701** will only use a createFlag of 2 after a prior call with a createFlag of 1 5702** failed.)^ In between the to xFetch() calls, SQLite may 5703** attempt to unpin one or more cache pages by spilling the content of 5704** pinned pages to disk and synching the operating system disk cache. 5705** 5706** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 5707** as its second argument. If the third parameter, discard, is non-zero, 5708** then the page must be evicted from the cache. 5709** ^If the discard parameter is 5710** zero, then the page may be discarded or retained at the discretion of 5711** page cache implementation. ^The page cache implementation 5712** may choose to evict unpinned pages at any time. 5713** 5714** The cache must not perform any reference counting. A single 5715** call to xUnpin() unpins the page regardless of the number of prior calls 5716** to xFetch(). 5717** 5718** The xRekey() method is used to change the key value associated with the 5719** page passed as the second argument. If the cache 5720** previously contains an entry associated with newKey, it must be 5721** discarded. ^Any prior cache entry associated with newKey is guaranteed not 5722** to be pinned. 5723** 5724** When SQLite calls the xTruncate() method, the cache must discard all 5725** existing cache entries with page numbers (keys) greater than or equal 5726** to the value of the iLimit parameter passed to xTruncate(). If any 5727** of these pages are pinned, they are implicitly unpinned, meaning that 5728** they can be safely discarded. 5729** 5730** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 5731** All resources associated with the specified cache should be freed. ^After 5732** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5733** handle invalid, and will not use it with any other sqlite3_pcache_methods 5734** functions. 5735*/ 5736typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5737struct sqlite3_pcache_methods { 5738 void *pArg; 5739 int (*xInit)(void*); 5740 void (*xShutdown)(void*); 5741 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5742 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5743 int (*xPagecount)(sqlite3_pcache*); 5744 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5745 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5746 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5747 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5748 void (*xDestroy)(sqlite3_pcache*); 5749}; 5750 5751/* 5752** CAPI3REF: Online Backup Object 5753** 5754** The sqlite3_backup object records state information about an ongoing 5755** online backup operation. ^The sqlite3_backup object is created by 5756** a call to [sqlite3_backup_init()] and is destroyed by a call to 5757** [sqlite3_backup_finish()]. 5758** 5759** See Also: [Using the SQLite Online Backup API] 5760*/ 5761typedef struct sqlite3_backup sqlite3_backup; 5762 5763/* 5764** CAPI3REF: Online Backup API. 5765** 5766** The backup API copies the content of one database into another. 5767** It is useful either for creating backups of databases or 5768** for copying in-memory databases to or from persistent files. 5769** 5770** See Also: [Using the SQLite Online Backup API] 5771** 5772** ^Exclusive access is required to the destination database for the 5773** duration of the operation. ^However the source database is only 5774** read-locked while it is actually being read; it is not locked 5775** continuously for the entire backup operation. ^Thus, the backup may be 5776** performed on a live source database without preventing other users from 5777** reading or writing to the source database while the backup is underway. 5778** 5779** ^(To perform a backup operation: 5780** <ol> 5781** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5782** backup, 5783** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5784** the data between the two databases, and finally 5785** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5786** associated with the backup operation. 5787** </ol>)^ 5788** There should be exactly one call to sqlite3_backup_finish() for each 5789** successful call to sqlite3_backup_init(). 5790** 5791** <b>sqlite3_backup_init()</b> 5792** 5793** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 5794** [database connection] associated with the destination database 5795** and the database name, respectively. 5796** ^The database name is "main" for the main database, "temp" for the 5797** temporary database, or the name specified after the AS keyword in 5798** an [ATTACH] statement for an attached database. 5799** ^The S and M arguments passed to 5800** sqlite3_backup_init(D,N,S,M) identify the [database connection] 5801** and database name of the source database, respectively. 5802** ^The source and destination [database connections] (parameters S and D) 5803** must be different or else sqlite3_backup_init(D,N,S,M) will file with 5804** an error. 5805** 5806** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 5807** returned and an error code and error message are store3d in the 5808** destination [database connection] D. 5809** ^The error code and message for the failed call to sqlite3_backup_init() 5810** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 5811** [sqlite3_errmsg16()] functions. 5812** ^A successful call to sqlite3_backup_init() returns a pointer to an 5813** [sqlite3_backup] object. 5814** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 5815** sqlite3_backup_finish() functions to perform the specified backup 5816** operation. 5817** 5818** <b>sqlite3_backup_step()</b> 5819** 5820** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 5821** the source and destination databases specified by [sqlite3_backup] object B. 5822** ^If N is negative, all remaining source pages are copied. 5823** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 5824** are still more pages to be copied, then the function resturns [SQLITE_OK]. 5825** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 5826** from source to destination, then it returns [SQLITE_DONE]. 5827** ^If an error occurs while running sqlite3_backup_step(B,N), 5828** then an [error code] is returned. ^As well as [SQLITE_OK] and 5829** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5830** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5831** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5832** 5833** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 5834** <ol> 5835** <li> the destination database was opened read-only, or 5836** <li> the destination database is using write-ahead-log journaling 5837** and the destination and source page sizes differ, or 5838** <li> The destination database is an in-memory database and the 5839** destination and source page sizes differ. 5840** </ol>)^ 5841** 5842** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 5843** the [sqlite3_busy_handler | busy-handler function] 5844** is invoked (if one is specified). ^If the 5845** busy-handler returns non-zero before the lock is available, then 5846** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 5847** sqlite3_backup_step() can be retried later. ^If the source 5848** [database connection] 5849** is being used to write to the source database when sqlite3_backup_step() 5850** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 5851** case the call to sqlite3_backup_step() can be retried later on. ^(If 5852** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5853** [SQLITE_READONLY] is returned, then 5854** there is no point in retrying the call to sqlite3_backup_step(). These 5855** errors are considered fatal.)^ The application must accept 5856** that the backup operation has failed and pass the backup operation handle 5857** to the sqlite3_backup_finish() to release associated resources. 5858** 5859** ^The first call to sqlite3_backup_step() obtains an exclusive lock 5860** on the destination file. ^The exclusive lock is not released until either 5861** sqlite3_backup_finish() is called or the backup operation is complete 5862** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 5863** sqlite3_backup_step() obtains a [shared lock] on the source database that 5864** lasts for the duration of the sqlite3_backup_step() call. 5865** ^Because the source database is not locked between calls to 5866** sqlite3_backup_step(), the source database may be modified mid-way 5867** through the backup process. ^If the source database is modified by an 5868** external process or via a database connection other than the one being 5869** used by the backup operation, then the backup will be automatically 5870** restarted by the next call to sqlite3_backup_step(). ^If the source 5871** database is modified by the using the same database connection as is used 5872** by the backup operation, then the backup database is automatically 5873** updated at the same time. 5874** 5875** <b>sqlite3_backup_finish()</b> 5876** 5877** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5878** application wishes to abandon the backup operation, the application 5879** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 5880** ^The sqlite3_backup_finish() interfaces releases all 5881** resources associated with the [sqlite3_backup] object. 5882** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 5883** active write-transaction on the destination database is rolled back. 5884** The [sqlite3_backup] object is invalid 5885** and may not be used following a call to sqlite3_backup_finish(). 5886** 5887** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 5888** sqlite3_backup_step() errors occurred, regardless or whether or not 5889** sqlite3_backup_step() completed. 5890** ^If an out-of-memory condition or IO error occurred during any prior 5891** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 5892** sqlite3_backup_finish() returns the corresponding [error code]. 5893** 5894** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 5895** is not a permanent error and does not affect the return value of 5896** sqlite3_backup_finish(). 5897** 5898** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5899** 5900** ^Each call to sqlite3_backup_step() sets two values inside 5901** the [sqlite3_backup] object: the number of pages still to be backed 5902** up and the total number of pages in the source database file. 5903** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 5904** retrieve these two values, respectively. 5905** 5906** ^The values returned by these functions are only updated by 5907** sqlite3_backup_step(). ^If the source database is modified during a backup 5908** operation, then the values are not updated to account for any extra 5909** pages that need to be updated or the size of the source database file 5910** changing. 5911** 5912** <b>Concurrent Usage of Database Handles</b> 5913** 5914** ^The source [database connection] may be used by the application for other 5915** purposes while a backup operation is underway or being initialized. 5916** ^If SQLite is compiled and configured to support threadsafe database 5917** connections, then the source database connection may be used concurrently 5918** from within other threads. 5919** 5920** However, the application must guarantee that the destination 5921** [database connection] is not passed to any other API (by any thread) after 5922** sqlite3_backup_init() is called and before the corresponding call to 5923** sqlite3_backup_finish(). SQLite does not currently check to see 5924** if the application incorrectly accesses the destination [database connection] 5925** and so no error code is reported, but the operations may malfunction 5926** nevertheless. Use of the destination database connection while a 5927** backup is in progress might also also cause a mutex deadlock. 5928** 5929** If running in [shared cache mode], the application must 5930** guarantee that the shared cache used by the destination database 5931** is not accessed while the backup is running. In practice this means 5932** that the application must guarantee that the disk file being 5933** backed up to is not accessed by any connection within the process, 5934** not just the specific connection that was passed to sqlite3_backup_init(). 5935** 5936** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5937** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5938** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5939** APIs are not strictly speaking threadsafe. If they are invoked at the 5940** same time as another thread is invoking sqlite3_backup_step() it is 5941** possible that they return invalid values. 5942*/ 5943SQLITE_API sqlite3_backup *sqlite3_backup_init( 5944 sqlite3 *pDest, /* Destination database handle */ 5945 const char *zDestName, /* Destination database name */ 5946 sqlite3 *pSource, /* Source database handle */ 5947 const char *zSourceName /* Source database name */ 5948); 5949SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5950SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); 5951SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); 5952SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); 5953 5954/* 5955** CAPI3REF: Unlock Notification 5956** 5957** ^When running in shared-cache mode, a database operation may fail with 5958** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5959** individual tables within the shared-cache cannot be obtained. See 5960** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5961** ^This API may be used to register a callback that SQLite will invoke 5962** when the connection currently holding the required lock relinquishes it. 5963** ^This API is only available if the library was compiled with the 5964** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5965** 5966** See Also: [Using the SQLite Unlock Notification Feature]. 5967** 5968** ^Shared-cache locks are released when a database connection concludes 5969** its current transaction, either by committing it or rolling it back. 5970** 5971** ^When a connection (known as the blocked connection) fails to obtain a 5972** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5973** identity of the database connection (the blocking connection) that 5974** has locked the required resource is stored internally. ^After an 5975** application receives an SQLITE_LOCKED error, it may call the 5976** sqlite3_unlock_notify() method with the blocked connection handle as 5977** the first argument to register for a callback that will be invoked 5978** when the blocking connections current transaction is concluded. ^The 5979** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5980** call that concludes the blocking connections transaction. 5981** 5982** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 5983** there is a chance that the blocking connection will have already 5984** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5985** If this happens, then the specified callback is invoked immediately, 5986** from within the call to sqlite3_unlock_notify().)^ 5987** 5988** ^If the blocked connection is attempting to obtain a write-lock on a 5989** shared-cache table, and more than one other connection currently holds 5990** a read-lock on the same table, then SQLite arbitrarily selects one of 5991** the other connections to use as the blocking connection. 5992** 5993** ^(There may be at most one unlock-notify callback registered by a 5994** blocked connection. If sqlite3_unlock_notify() is called when the 5995** blocked connection already has a registered unlock-notify callback, 5996** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 5997** called with a NULL pointer as its second argument, then any existing 5998** unlock-notify callback is canceled. ^The blocked connections 5999** unlock-notify callback may also be canceled by closing the blocked 6000** connection using [sqlite3_close()]. 6001** 6002** The unlock-notify callback is not reentrant. If an application invokes 6003** any sqlite3_xxx API functions from within an unlock-notify callback, a 6004** crash or deadlock may be the result. 6005** 6006** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6007** returns SQLITE_OK. 6008** 6009** <b>Callback Invocation Details</b> 6010** 6011** When an unlock-notify callback is registered, the application provides a 6012** single void* pointer that is passed to the callback when it is invoked. 6013** However, the signature of the callback function allows SQLite to pass 6014** it an array of void* context pointers. The first argument passed to 6015** an unlock-notify callback is a pointer to an array of void* pointers, 6016** and the second is the number of entries in the array. 6017** 6018** When a blocking connections transaction is concluded, there may be 6019** more than one blocked connection that has registered for an unlock-notify 6020** callback. ^If two or more such blocked connections have specified the 6021** same callback function, then instead of invoking the callback function 6022** multiple times, it is invoked once with the set of void* context pointers 6023** specified by the blocked connections bundled together into an array. 6024** This gives the application an opportunity to prioritize any actions 6025** related to the set of unblocked database connections. 6026** 6027** <b>Deadlock Detection</b> 6028** 6029** Assuming that after registering for an unlock-notify callback a 6030** database waits for the callback to be issued before taking any further 6031** action (a reasonable assumption), then using this API may cause the 6032** application to deadlock. For example, if connection X is waiting for 6033** connection Y's transaction to be concluded, and similarly connection 6034** Y is waiting on connection X's transaction, then neither connection 6035** will proceed and the system may remain deadlocked indefinitely. 6036** 6037** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6038** detection. ^If a given call to sqlite3_unlock_notify() would put the 6039** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6040** unlock-notify callback is registered. The system is said to be in 6041** a deadlocked state if connection A has registered for an unlock-notify 6042** callback on the conclusion of connection B's transaction, and connection 6043** B has itself registered for an unlock-notify callback when connection 6044** A's transaction is concluded. ^Indirect deadlock is also detected, so 6045** the system is also considered to be deadlocked if connection B has 6046** registered for an unlock-notify callback on the conclusion of connection 6047** C's transaction, where connection C is waiting on connection A. ^Any 6048** number of levels of indirection are allowed. 6049** 6050** <b>The "DROP TABLE" Exception</b> 6051** 6052** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6053** always appropriate to call sqlite3_unlock_notify(). There is however, 6054** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6055** SQLite checks if there are any currently executing SELECT statements 6056** that belong to the same connection. If there are, SQLITE_LOCKED is 6057** returned. In this case there is no "blocking connection", so invoking 6058** sqlite3_unlock_notify() results in the unlock-notify callback being 6059** invoked immediately. If the application then re-attempts the "DROP TABLE" 6060** or "DROP INDEX" query, an infinite loop might be the result. 6061** 6062** One way around this problem is to check the extended error code returned 6063** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6064** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6065** the special "DROP TABLE/INDEX" case, the extended error code is just 6066** SQLITE_LOCKED.)^ 6067*/ 6068SQLITE_API int sqlite3_unlock_notify( 6069 sqlite3 *pBlocked, /* Waiting connection */ 6070 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6071 void *pNotifyArg /* Argument to pass to xNotify */ 6072); 6073 6074 6075/* 6076** CAPI3REF: String Comparison 6077** 6078** ^The [sqlite3_strnicmp()] API allows applications and extensions to 6079** compare the contents of two buffers containing UTF-8 strings in a 6080** case-independent fashion, using the same definition of case independence 6081** that SQLite uses internally when comparing identifiers. 6082*/ 6083SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); 6084 6085/* 6086** CAPI3REF: Error Logging Interface 6087** 6088** ^The [sqlite3_log()] interface writes a message into the error log 6089** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6090** ^If logging is enabled, the zFormat string and subsequent arguments are 6091** used with [sqlite3_snprintf()] to generate the final output string. 6092** 6093** The sqlite3_log() interface is intended for use by extensions such as 6094** virtual tables, collating functions, and SQL functions. While there is 6095** nothing to prevent an application from calling sqlite3_log(), doing so 6096** is considered bad form. 6097** 6098** The zFormat string must not be NULL. 6099** 6100** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6101** will not use dynamically allocated memory. The log message is stored in 6102** a fixed-length buffer on the stack. If the log message is longer than 6103** a few hundred characters, it will be truncated to the length of the 6104** buffer. 6105*/ 6106SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); 6107 6108/* 6109** CAPI3REF: Write-Ahead Log Commit Hook 6110** 6111** ^The [sqlite3_wal_hook()] function is used to register a callback that 6112** will be invoked each time a database connection commits data to a 6113** [write-ahead log] (i.e. whenever a transaction is committed in 6114** [journal_mode | journal_mode=WAL mode]). 6115** 6116** ^The callback is invoked by SQLite after the commit has taken place and 6117** the associated write-lock on the database released, so the implementation 6118** may read, write or [checkpoint] the database as required. 6119** 6120** ^The first parameter passed to the callback function when it is invoked 6121** is a copy of the third parameter passed to sqlite3_wal_hook() when 6122** registering the callback. ^The second is a copy of the database handle. 6123** ^The third parameter is the name of the database that was written to - 6124** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6125** is the number of pages currently in the write-ahead log file, 6126** including those that were just committed. 6127** 6128** The callback function should normally return [SQLITE_OK]. ^If an error 6129** code is returned, that error will propagate back up through the 6130** SQLite code base to cause the statement that provoked the callback 6131** to report an error, though the commit will have still occurred. If the 6132** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6133** that does not correspond to any valid SQLite error code, the results 6134** are undefined. 6135** 6136** A single database handle may have at most a single write-ahead log callback 6137** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6138** previously registered write-ahead log callback. ^Note that the 6139** [sqlite3_wal_autocheckpoint()] interface and the 6140** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6141** those overwrite any prior [sqlite3_wal_hook()] settings. 6142*/ 6143SQLITE_API void *sqlite3_wal_hook( 6144 sqlite3*, 6145 int(*)(void *,sqlite3*,const char*,int), 6146 void* 6147); 6148 6149/* 6150** CAPI3REF: Configure an auto-checkpoint 6151** 6152** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6153** [sqlite3_wal_hook()] that causes any database on [database connection] D 6154** to automatically [checkpoint] 6155** after committing a transaction if there are N or 6156** more frames in the [write-ahead log] file. ^Passing zero or 6157** a negative value as the nFrame parameter disables automatic 6158** checkpoints entirely. 6159** 6160** ^The callback registered by this function replaces any existing callback 6161** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6162** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6163** configured by this function. 6164** 6165** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6166** from SQL. 6167** 6168** ^Every new [database connection] defaults to having the auto-checkpoint 6169** enabled with a threshold of 1000 pages. The use of this interface 6170** is only necessary if the default setting is found to be suboptimal 6171** for a particular application. 6172*/ 6173SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6174 6175/* 6176** CAPI3REF: Checkpoint a database 6177** 6178** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6179** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6180** empty string, then a checkpoint is run on all databases of 6181** connection D. ^If the database connection D is not in 6182** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6183** 6184** ^The [wal_checkpoint pragma] can be used to invoke this interface 6185** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6186** [wal_autocheckpoint pragma] can be used to cause this interface to be 6187** run whenever the WAL reaches a certain size threshold. 6188*/ 6189SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6190 6191/* 6192** Undo the hack that converts floating point types to integer for 6193** builds on processors without floating point support. 6194*/ 6195#ifdef SQLITE_OMIT_FLOATING_POINT 6196# undef double 6197#endif 6198 6199#ifdef __cplusplus 6200} /* End of the 'extern "C"' block */ 6201#endif 6202#endif 6203 6204/* 6205** 2010 August 30 6206** 6207** The author disclaims copyright to this source code. In place of 6208** a legal notice, here is a blessing: 6209** 6210** May you do good and not evil. 6211** May you find forgiveness for yourself and forgive others. 6212** May you share freely, never taking more than you give. 6213** 6214************************************************************************* 6215*/ 6216 6217#ifndef _SQLITE3RTREE_H_ 6218#define _SQLITE3RTREE_H_ 6219 6220 6221#ifdef __cplusplus 6222extern "C" { 6223#endif 6224 6225typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry; 6226 6227/* 6228** Register a geometry callback named zGeom that can be used as part of an 6229** R-Tree geometry query as follows: 6230** 6231** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...) 6232*/ 6233SQLITE_API int sqlite3_rtree_geometry_callback( 6234 sqlite3 *db, 6235 const char *zGeom, 6236 int (*xGeom)(sqlite3_rtree_geometry *, int nCoord, double *aCoord, int *pRes), 6237 void *pContext 6238); 6239 6240 6241/* 6242** A pointer to a structure of the following type is passed as the first 6243** argument to callbacks registered using rtree_geometry_callback(). 6244*/ 6245struct sqlite3_rtree_geometry { 6246 void *pContext; /* Copy of pContext passed to s_r_g_c() */ 6247 int nParam; /* Size of array aParam[] */ 6248 double *aParam; /* Parameters passed to SQL geom function */ 6249 void *pUser; /* Callback implementation user data */ 6250 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */ 6251}; 6252 6253 6254#ifdef __cplusplus 6255} /* end of the 'extern "C"' block */ 6256#endif 6257 6258#endif /* ifndef _SQLITE3RTREE_H_ */ 6259 6260