1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are suppose to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef _SQLITE3_H_ 34#define _SQLITE3_H_ 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Add the ability to override 'extern' 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51 52/* 53** These no-op macros are used in front of interfaces to mark those 54** interfaces as either deprecated or experimental. New applications 55** should not use deprecated interfaces - they are support for backwards 56** compatibility only. Application writers should be aware that 57** experimental interfaces are subject to change in point releases. 58** 59** These macros used to resolve to various kinds of compiler magic that 60** would generate warning messages when they were used. But that 61** compiler magic ended up generating such a flurry of bug reports 62** that we have taken it all out and gone back to using simple 63** noop macros. 64*/ 65#define SQLITE_DEPRECATED 66#define SQLITE_EXPERIMENTAL 67 68/* 69** Ensure these symbols were not defined by some previous header file. 70*/ 71#ifdef SQLITE_VERSION 72# undef SQLITE_VERSION 73#endif 74#ifdef SQLITE_VERSION_NUMBER 75# undef SQLITE_VERSION_NUMBER 76#endif 77 78/* 79** CAPI3REF: Compile-Time Library Version Numbers 80** 81** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 82** evaluates to a string literal that is the SQLite version in the 83** format "X.Y.Z" where X is the major version number (always 3 for 84** SQLite3) and Y is the minor version number and Z is the release number.)^ 85** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 86** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 87** numbers used in [SQLITE_VERSION].)^ 88** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 89** be larger than the release from which it is derived. Either Y will 90** be held constant and Z will be incremented or else Y will be incremented 91** and Z will be reset to zero. 92** 93** Since version 3.6.18, SQLite source code has been stored in the 94** <a href="http://www.fossil-scm.org/">Fossil configuration management 95** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 96** a string which identifies a particular check-in of SQLite 97** within its configuration management system. ^The SQLITE_SOURCE_ID 98** string contains the date and time of the check-in (UTC) and an SHA1 99** hash of the entire source tree. 100** 101** See also: [sqlite3_libversion()], 102** [sqlite3_libversion_number()], [sqlite3_sourceid()], 103** [sqlite_version()] and [sqlite_source_id()]. 104*/ 105#define SQLITE_VERSION "--VERS--" 106#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 107#define SQLITE_SOURCE_ID "--SOURCE-ID--" 108 109/* 110** CAPI3REF: Run-Time Library Version Numbers 111** KEYWORDS: sqlite3_version, sqlite3_sourceid 112** 113** These interfaces provide the same information as the [SQLITE_VERSION], 114** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 115** but are associated with the library instead of the header file. ^(Cautious 116** programmers might include assert() statements in their application to 117** verify that values returned by these interfaces match the macros in 118** the header, and thus insure that the application is 119** compiled with matching library and header files. 120** 121** <blockquote><pre> 122** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 123** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 124** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 125** </pre></blockquote>)^ 126** 127** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 128** macro. ^The sqlite3_libversion() function returns a pointer to the 129** to the sqlite3_version[] string constant. The sqlite3_libversion() 130** function is provided for use in DLLs since DLL users usually do not have 131** direct access to string constants within the DLL. ^The 132** sqlite3_libversion_number() function returns an integer equal to 133** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 134** a pointer to a string constant whose value is the same as the 135** [SQLITE_SOURCE_ID] C preprocessor macro. 136** 137** See also: [sqlite_version()] and [sqlite_source_id()]. 138*/ 139SQLITE_EXTERN const char sqlite3_version[]; 140const char *sqlite3_libversion(void); 141const char *sqlite3_sourceid(void); 142int sqlite3_libversion_number(void); 143 144/* 145** CAPI3REF: Run-Time Library Compilation Options Diagnostics 146** 147** ^The sqlite3_compileoption_used() function returns 0 or 1 148** indicating whether the specified option was defined at 149** compile time. ^The SQLITE_ prefix may be omitted from the 150** option name passed to sqlite3_compileoption_used(). 151** 152** ^The sqlite3_compileoption_get() function allows iterating 153** over the list of options that were defined at compile time by 154** returning the N-th compile time option string. ^If N is out of range, 155** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 156** prefix is omitted from any strings returned by 157** sqlite3_compileoption_get(). 158** 159** ^Support for the diagnostic functions sqlite3_compileoption_used() 160** and sqlite3_compileoption_get() may be omitted by specifying the 161** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 162** 163** See also: SQL functions [sqlite_compileoption_used()] and 164** [sqlite_compileoption_get()] and the [compile_options pragma]. 165*/ 166#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 167int sqlite3_compileoption_used(const char *zOptName); 168const char *sqlite3_compileoption_get(int N); 169#endif 170 171/* 172** CAPI3REF: Test To See If The Library Is Threadsafe 173** 174** ^The sqlite3_threadsafe() function returns zero if and only if 175** SQLite was compiled with mutexing code omitted due to the 176** [SQLITE_THREADSAFE] compile-time option being set to 0. 177** 178** SQLite can be compiled with or without mutexes. When 179** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 180** are enabled and SQLite is threadsafe. When the 181** [SQLITE_THREADSAFE] macro is 0, 182** the mutexes are omitted. Without the mutexes, it is not safe 183** to use SQLite concurrently from more than one thread. 184** 185** Enabling mutexes incurs a measurable performance penalty. 186** So if speed is of utmost importance, it makes sense to disable 187** the mutexes. But for maximum safety, mutexes should be enabled. 188** ^The default behavior is for mutexes to be enabled. 189** 190** This interface can be used by an application to make sure that the 191** version of SQLite that it is linking against was compiled with 192** the desired setting of the [SQLITE_THREADSAFE] macro. 193** 194** This interface only reports on the compile-time mutex setting 195** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 196** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 197** can be fully or partially disabled using a call to [sqlite3_config()] 198** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 199** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 200** sqlite3_threadsafe() function shows only the compile-time setting of 201** thread safety, not any run-time changes to that setting made by 202** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 203** is unchanged by calls to sqlite3_config().)^ 204** 205** See the [threading mode] documentation for additional information. 206*/ 207int sqlite3_threadsafe(void); 208 209/* 210** CAPI3REF: Database Connection Handle 211** KEYWORDS: {database connection} {database connections} 212** 213** Each open SQLite database is represented by a pointer to an instance of 214** the opaque structure named "sqlite3". It is useful to think of an sqlite3 215** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 216** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 217** is its destructor. There are many other interfaces (such as 218** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 219** [sqlite3_busy_timeout()] to name but three) that are methods on an 220** sqlite3 object. 221*/ 222typedef struct sqlite3 sqlite3; 223 224/* 225** CAPI3REF: 64-Bit Integer Types 226** KEYWORDS: sqlite_int64 sqlite_uint64 227** 228** Because there is no cross-platform way to specify 64-bit integer types 229** SQLite includes typedefs for 64-bit signed and unsigned integers. 230** 231** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 232** The sqlite_int64 and sqlite_uint64 types are supported for backwards 233** compatibility only. 234** 235** ^The sqlite3_int64 and sqlite_int64 types can store integer values 236** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 237** sqlite3_uint64 and sqlite_uint64 types can store integer values 238** between 0 and +18446744073709551615 inclusive. 239*/ 240#ifdef SQLITE_INT64_TYPE 241 typedef SQLITE_INT64_TYPE sqlite_int64; 242 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 243#elif defined(_MSC_VER) || defined(__BORLANDC__) 244 typedef __int64 sqlite_int64; 245 typedef unsigned __int64 sqlite_uint64; 246#else 247 typedef long long int sqlite_int64; 248 typedef unsigned long long int sqlite_uint64; 249#endif 250typedef sqlite_int64 sqlite3_int64; 251typedef sqlite_uint64 sqlite3_uint64; 252 253/* 254** If compiling for a processor that lacks floating point support, 255** substitute integer for floating-point. 256*/ 257#ifdef SQLITE_OMIT_FLOATING_POINT 258# define double sqlite3_int64 259#endif 260 261/* 262** CAPI3REF: Closing A Database Connection 263** 264** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 265** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 266** successfully destroyed and all associated resources are deallocated. 267** 268** Applications must [sqlite3_finalize | finalize] all [prepared statements] 269** and [sqlite3_blob_close | close] all [BLOB handles] associated with 270** the [sqlite3] object prior to attempting to close the object. ^If 271** sqlite3_close() is called on a [database connection] that still has 272** outstanding [prepared statements] or [BLOB handles], then it returns 273** SQLITE_BUSY. 274** 275** ^If [sqlite3_close()] is invoked while a transaction is open, 276** the transaction is automatically rolled back. 277** 278** The C parameter to [sqlite3_close(C)] must be either a NULL 279** pointer or an [sqlite3] object pointer obtained 280** from [sqlite3_open()], [sqlite3_open16()], or 281** [sqlite3_open_v2()], and not previously closed. 282** ^Calling sqlite3_close() with a NULL pointer argument is a 283** harmless no-op. 284*/ 285int sqlite3_close(sqlite3 *); 286 287/* 288** The type for a callback function. 289** This is legacy and deprecated. It is included for historical 290** compatibility and is not documented. 291*/ 292typedef int (*sqlite3_callback)(void*,int,char**, char**); 293 294/* 295** CAPI3REF: One-Step Query Execution Interface 296** 297** The sqlite3_exec() interface is a convenience wrapper around 298** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 299** that allows an application to run multiple statements of SQL 300** without having to use a lot of C code. 301** 302** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 303** semicolon-separate SQL statements passed into its 2nd argument, 304** in the context of the [database connection] passed in as its 1st 305** argument. ^If the callback function of the 3rd argument to 306** sqlite3_exec() is not NULL, then it is invoked for each result row 307** coming out of the evaluated SQL statements. ^The 4th argument to 308** sqlite3_exec() is relayed through to the 1st argument of each 309** callback invocation. ^If the callback pointer to sqlite3_exec() 310** is NULL, then no callback is ever invoked and result rows are 311** ignored. 312** 313** ^If an error occurs while evaluating the SQL statements passed into 314** sqlite3_exec(), then execution of the current statement stops and 315** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 316** is not NULL then any error message is written into memory obtained 317** from [sqlite3_malloc()] and passed back through the 5th parameter. 318** To avoid memory leaks, the application should invoke [sqlite3_free()] 319** on error message strings returned through the 5th parameter of 320** of sqlite3_exec() after the error message string is no longer needed. 321** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 322** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 323** NULL before returning. 324** 325** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 326** routine returns SQLITE_ABORT without invoking the callback again and 327** without running any subsequent SQL statements. 328** 329** ^The 2nd argument to the sqlite3_exec() callback function is the 330** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 331** callback is an array of pointers to strings obtained as if from 332** [sqlite3_column_text()], one for each column. ^If an element of a 333** result row is NULL then the corresponding string pointer for the 334** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 335** sqlite3_exec() callback is an array of pointers to strings where each 336** entry represents the name of corresponding result column as obtained 337** from [sqlite3_column_name()]. 338** 339** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 340** to an empty string, or a pointer that contains only whitespace and/or 341** SQL comments, then no SQL statements are evaluated and the database 342** is not changed. 343** 344** Restrictions: 345** 346** <ul> 347** <li> The application must insure that the 1st parameter to sqlite3_exec() 348** is a valid and open [database connection]. 349** <li> The application must not close [database connection] specified by 350** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 351** <li> The application must not modify the SQL statement text passed into 352** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 353** </ul> 354*/ 355int sqlite3_exec( 356 sqlite3*, /* An open database */ 357 const char *sql, /* SQL to be evaluated */ 358 int (*callback)(void*,int,char**,char**), /* Callback function */ 359 void *, /* 1st argument to callback */ 360 char **errmsg /* Error msg written here */ 361); 362 363/* 364** CAPI3REF: Result Codes 365** KEYWORDS: SQLITE_OK {error code} {error codes} 366** KEYWORDS: {result code} {result codes} 367** 368** Many SQLite functions return an integer result code from the set shown 369** here in order to indicate success or failure. 370** 371** New error codes may be added in future versions of SQLite. 372** 373** See also: [SQLITE_IOERR_READ | extended result codes], 374** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes]. 375*/ 376#define SQLITE_OK 0 /* Successful result */ 377/* beginning-of-error-codes */ 378#define SQLITE_ERROR 1 /* SQL error or missing database */ 379#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 380#define SQLITE_PERM 3 /* Access permission denied */ 381#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 382#define SQLITE_BUSY 5 /* The database file is locked */ 383#define SQLITE_LOCKED 6 /* A table in the database is locked */ 384#define SQLITE_NOMEM 7 /* A malloc() failed */ 385#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 386#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 387#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 388#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 389#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 390#define SQLITE_FULL 13 /* Insertion failed because database is full */ 391#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 392#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 393#define SQLITE_EMPTY 16 /* Database is empty */ 394#define SQLITE_SCHEMA 17 /* The database schema changed */ 395#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 396#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 397#define SQLITE_MISMATCH 20 /* Data type mismatch */ 398#define SQLITE_MISUSE 21 /* Library used incorrectly */ 399#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 400#define SQLITE_AUTH 23 /* Authorization denied */ 401#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 402#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 403#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 404#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 405#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 406/* end-of-error-codes */ 407 408/* 409** CAPI3REF: Extended Result Codes 410** KEYWORDS: {extended error code} {extended error codes} 411** KEYWORDS: {extended result code} {extended result codes} 412** 413** In its default configuration, SQLite API routines return one of 26 integer 414** [SQLITE_OK | result codes]. However, experience has shown that many of 415** these result codes are too coarse-grained. They do not provide as 416** much information about problems as programmers might like. In an effort to 417** address this, newer versions of SQLite (version 3.3.8 and later) include 418** support for additional result codes that provide more detailed information 419** about errors. The extended result codes are enabled or disabled 420** on a per database connection basis using the 421** [sqlite3_extended_result_codes()] API. 422** 423** Some of the available extended result codes are listed here. 424** One may expect the number of extended result codes will be expand 425** over time. Software that uses extended result codes should expect 426** to see new result codes in future releases of SQLite. 427** 428** The SQLITE_OK result code will never be extended. It will always 429** be exactly zero. 430*/ 431#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 432#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 433#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 434#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 435#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 436#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 437#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 438#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 439#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 440#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 441#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 442#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 443#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 444#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 445#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 446#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 447#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 448#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 449#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 450#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 451#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 452#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 453#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 454#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 455#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 456#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 457#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 458#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 459#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 460#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<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 [sqlite3_vfs.xOpen] method. 468*/ 469#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 470#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 471#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 472#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 473#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 474#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 475#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 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/* Reserved: 0x00F00000 */ 490 491/* 492** CAPI3REF: Device Characteristics 493** 494** The xDeviceCharacteristics method of the [sqlite3_io_methods] 495** object returns an integer which is a vector of the these 496** bit values expressing I/O characteristics of the mass storage 497** device that holds the file that the [sqlite3_io_methods] 498** refers to. 499** 500** The SQLITE_IOCAP_ATOMIC property means that all writes of 501** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 502** mean that writes of blocks that are nnn bytes in size and 503** are aligned to an address which is an integer multiple of 504** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 505** that when data is appended to a file, the data is appended 506** first then the size of the file is extended, never the other 507** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 508** information is written to disk in the same order as calls 509** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 510** after reboot following a crash or power loss, the only bytes in a 511** file that were written at the application level might have changed 512** and that adjacent bytes, even bytes within the same sector are 513** guaranteed to be unchanged. 514*/ 515#define SQLITE_IOCAP_ATOMIC 0x00000001 516#define SQLITE_IOCAP_ATOMIC512 0x00000002 517#define SQLITE_IOCAP_ATOMIC1K 0x00000004 518#define SQLITE_IOCAP_ATOMIC2K 0x00000008 519#define SQLITE_IOCAP_ATOMIC4K 0x00000010 520#define SQLITE_IOCAP_ATOMIC8K 0x00000020 521#define SQLITE_IOCAP_ATOMIC16K 0x00000040 522#define SQLITE_IOCAP_ATOMIC32K 0x00000080 523#define SQLITE_IOCAP_ATOMIC64K 0x00000100 524#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 525#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 526#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 527#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 528 529/* 530** CAPI3REF: File Locking Levels 531** 532** SQLite uses one of these integer values as the second 533** argument to calls it makes to the xLock() and xUnlock() methods 534** of an [sqlite3_io_methods] object. 535*/ 536#define SQLITE_LOCK_NONE 0 537#define SQLITE_LOCK_SHARED 1 538#define SQLITE_LOCK_RESERVED 2 539#define SQLITE_LOCK_PENDING 3 540#define SQLITE_LOCK_EXCLUSIVE 4 541 542/* 543** CAPI3REF: Synchronization Type Flags 544** 545** When SQLite invokes the xSync() method of an 546** [sqlite3_io_methods] object it uses a combination of 547** these integer values as the second argument. 548** 549** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 550** sync operation only needs to flush data to mass storage. Inode 551** information need not be flushed. If the lower four bits of the flag 552** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 553** If the lower four bits equal SQLITE_SYNC_FULL, that means 554** to use Mac OS X style fullsync instead of fsync(). 555** 556** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 557** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 558** settings. The [synchronous pragma] determines when calls to the 559** xSync VFS method occur and applies uniformly across all platforms. 560** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 561** energetic or rigorous or forceful the sync operations are and 562** only make a difference on Mac OSX for the default SQLite code. 563** (Third-party VFS implementations might also make the distinction 564** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 565** operating systems natively supported by SQLite, only Mac OSX 566** cares about the difference.) 567*/ 568#define SQLITE_SYNC_NORMAL 0x00002 569#define SQLITE_SYNC_FULL 0x00003 570#define SQLITE_SYNC_DATAONLY 0x00010 571 572/* 573** CAPI3REF: OS Interface Open File Handle 574** 575** An [sqlite3_file] object represents an open file in the 576** [sqlite3_vfs | OS interface layer]. Individual OS interface 577** implementations will 578** want to subclass this object by appending additional fields 579** for their own use. The pMethods entry is a pointer to an 580** [sqlite3_io_methods] object that defines methods for performing 581** I/O operations on the open file. 582*/ 583typedef struct sqlite3_file sqlite3_file; 584struct sqlite3_file { 585 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 586}; 587 588/* 589** CAPI3REF: OS Interface File Virtual Methods Object 590** 591** Every file opened by the [sqlite3_vfs.xOpen] method populates an 592** [sqlite3_file] object (or, more commonly, a subclass of the 593** [sqlite3_file] object) with a pointer to an instance of this object. 594** This object defines the methods used to perform various operations 595** against the open file represented by the [sqlite3_file] object. 596** 597** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 598** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 599** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 600** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 601** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 602** to NULL. 603** 604** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 605** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 606** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 607** flag may be ORed in to indicate that only the data of the file 608** and not its inode needs to be synced. 609** 610** The integer values to xLock() and xUnlock() are one of 611** <ul> 612** <li> [SQLITE_LOCK_NONE], 613** <li> [SQLITE_LOCK_SHARED], 614** <li> [SQLITE_LOCK_RESERVED], 615** <li> [SQLITE_LOCK_PENDING], or 616** <li> [SQLITE_LOCK_EXCLUSIVE]. 617** </ul> 618** xLock() increases the lock. xUnlock() decreases the lock. 619** The xCheckReservedLock() method checks whether any database connection, 620** either in this process or in some other process, is holding a RESERVED, 621** PENDING, or EXCLUSIVE lock on the file. It returns true 622** if such a lock exists and false otherwise. 623** 624** The xFileControl() method is a generic interface that allows custom 625** VFS implementations to directly control an open file using the 626** [sqlite3_file_control()] interface. The second "op" argument is an 627** integer opcode. The third argument is a generic pointer intended to 628** point to a structure that may contain arguments or space in which to 629** write return values. Potential uses for xFileControl() might be 630** functions to enable blocking locks with timeouts, to change the 631** locking strategy (for example to use dot-file locks), to inquire 632** about the status of a lock, or to break stale locks. The SQLite 633** core reserves all opcodes less than 100 for its own use. 634** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 635** Applications that define a custom xFileControl method should use opcodes 636** greater than 100 to avoid conflicts. VFS implementations should 637** return [SQLITE_NOTFOUND] for file control opcodes that they do not 638** recognize. 639** 640** The xSectorSize() method returns the sector size of the 641** device that underlies the file. The sector size is the 642** minimum write that can be performed without disturbing 643** other bytes in the file. The xDeviceCharacteristics() 644** method returns a bit vector describing behaviors of the 645** underlying device: 646** 647** <ul> 648** <li> [SQLITE_IOCAP_ATOMIC] 649** <li> [SQLITE_IOCAP_ATOMIC512] 650** <li> [SQLITE_IOCAP_ATOMIC1K] 651** <li> [SQLITE_IOCAP_ATOMIC2K] 652** <li> [SQLITE_IOCAP_ATOMIC4K] 653** <li> [SQLITE_IOCAP_ATOMIC8K] 654** <li> [SQLITE_IOCAP_ATOMIC16K] 655** <li> [SQLITE_IOCAP_ATOMIC32K] 656** <li> [SQLITE_IOCAP_ATOMIC64K] 657** <li> [SQLITE_IOCAP_SAFE_APPEND] 658** <li> [SQLITE_IOCAP_SEQUENTIAL] 659** </ul> 660** 661** The SQLITE_IOCAP_ATOMIC property means that all writes of 662** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 663** mean that writes of blocks that are nnn bytes in size and 664** are aligned to an address which is an integer multiple of 665** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 666** that when data is appended to a file, the data is appended 667** first then the size of the file is extended, never the other 668** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 669** information is written to disk in the same order as calls 670** to xWrite(). 671** 672** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 673** in the unread portions of the buffer with zeros. A VFS that 674** fails to zero-fill short reads might seem to work. However, 675** failure to zero-fill short reads will eventually lead to 676** database corruption. 677*/ 678typedef struct sqlite3_io_methods sqlite3_io_methods; 679struct sqlite3_io_methods { 680 int iVersion; 681 int (*xClose)(sqlite3_file*); 682 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 683 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 684 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 685 int (*xSync)(sqlite3_file*, int flags); 686 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 687 int (*xLock)(sqlite3_file*, int); 688 int (*xUnlock)(sqlite3_file*, int); 689 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 690 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 691 int (*xSectorSize)(sqlite3_file*); 692 int (*xDeviceCharacteristics)(sqlite3_file*); 693 /* Methods above are valid for version 1 */ 694 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 695 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 696 void (*xShmBarrier)(sqlite3_file*); 697 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 698 /* Methods above are valid for version 2 */ 699 /* Additional methods may be added in future releases */ 700}; 701 702/* 703** CAPI3REF: Standard File Control Opcodes 704** 705** These integer constants are opcodes for the xFileControl method 706** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 707** interface. 708** 709** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 710** opcode causes the xFileControl method to write the current state of 711** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 712** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 713** into an integer that the pArg argument points to. This capability 714** is used during testing and only needs to be supported when SQLITE_TEST 715** is defined. 716** <ul> 717** <li>[[SQLITE_FCNTL_SIZE_HINT]] 718** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 719** layer a hint of how large the database file will grow to be during the 720** current transaction. This hint is not guaranteed to be accurate but it 721** is often close. The underlying VFS might choose to preallocate database 722** file space based on this hint in order to help writes to the database 723** file run faster. 724** 725** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 726** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 727** extends and truncates the database file in chunks of a size specified 728** by the user. The fourth argument to [sqlite3_file_control()] should 729** point to an integer (type int) containing the new chunk-size to use 730** for the nominated database. Allocating database file space in large 731** chunks (say 1MB at a time), may reduce file-system fragmentation and 732** improve performance on some systems. 733** 734** <li>[[SQLITE_FCNTL_FILE_POINTER]] 735** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 736** to the [sqlite3_file] object associated with a particular database 737** connection. See the [sqlite3_file_control()] documentation for 738** additional information. 739** 740** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 741** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by 742** SQLite and sent to all VFSes in place of a call to the xSync method 743** when the database connection has [PRAGMA synchronous] set to OFF.)^ 744** Some specialized VFSes need this signal in order to operate correctly 745** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 746** VFSes do not need this signal and should silently ignore this opcode. 747** Applications should not call [sqlite3_file_control()] with this 748** opcode as doing so may disrupt the operation of the specialized VFSes 749** that do require it. 750** 751** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 752** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 753** retry counts and intervals for certain disk I/O operations for the 754** windows [VFS] in order to provide robustness in the presence of 755** anti-virus programs. By default, the windows VFS will retry file read, 756** file write, and file delete operations up to 10 times, with a delay 757** of 25 milliseconds before the first retry and with the delay increasing 758** by an additional 25 milliseconds with each subsequent retry. This 759** opcode allows these two values (10 retries and 25 milliseconds of delay) 760** to be adjusted. The values are changed for all database connections 761** within the same process. The argument is a pointer to an array of two 762** integers where the first integer i the new retry count and the second 763** integer is the delay. If either integer is negative, then the setting 764** is not changed but instead the prior value of that setting is written 765** into the array entry, allowing the current retry settings to be 766** interrogated. The zDbName parameter is ignored. 767** 768** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 769** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 770** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 771** write ahead log and shared memory files used for transaction control 772** are automatically deleted when the latest connection to the database 773** closes. Setting persistent WAL mode causes those files to persist after 774** close. Persisting the files is useful when other processes that do not 775** have write permission on the directory containing the database file want 776** to read the database file, as the WAL and shared memory files must exist 777** in order for the database to be readable. The fourth parameter to 778** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 779** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 780** WAL mode. If the integer is -1, then it is overwritten with the current 781** WAL persistence setting. 782** 783** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 784** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 785** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 786** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 787** xDeviceCharacteristics methods. The fourth parameter to 788** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 789** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 790** mode. If the integer is -1, then it is overwritten with the current 791** zero-damage mode setting. 792** 793** <li>[[SQLITE_FCNTL_OVERWRITE]] 794** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 795** a write transaction to indicate that, unless it is rolled back for some 796** reason, the entire database file will be overwritten by the current 797** transaction. This is used by VACUUM operations. 798** 799** <li>[[SQLITE_FCNTL_VFSNAME]] 800** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 801** all [VFSes] in the VFS stack. The names are of all VFS shims and the 802** final bottom-level VFS are written into memory obtained from 803** [sqlite3_malloc()] and the result is stored in the char* variable 804** that the fourth parameter of [sqlite3_file_control()] points to. 805** The caller is responsible for freeing the memory when done. As with 806** all file-control actions, there is no guarantee that this will actually 807** do anything. Callers should initialize the char* variable to a NULL 808** pointer in case this file-control is not implemented. This file-control 809** is intended for diagnostic use only. 810** 811** <li>[[SQLITE_FCNTL_PRAGMA]] 812** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 813** file control is sent to the open [sqlite3_file] object corresponding 814** to the database file to which the pragma statement refers. ^The argument 815** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 816** pointers to strings (char**) in which the second element of the array 817** is the name of the pragma and the third element is the argument to the 818** pragma or NULL if the pragma has no argument. ^The handler for an 819** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 820** of the char** argument point to a string obtained from [sqlite3_mprintf()] 821** or the equivalent and that string will become the result of the pragma or 822** the error message if the pragma fails. ^If the 823** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 824** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 825** file control returns [SQLITE_OK], then the parser assumes that the 826** VFS has handled the PRAGMA itself and the parser generates a no-op 827** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns 828** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 829** that the VFS encountered an error while handling the [PRAGMA] and the 830** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 831** file control occurs at the beginning of pragma statement analysis and so 832** it is able to override built-in [PRAGMA] statements. 833** </ul> 834*/ 835#define SQLITE_FCNTL_LOCKSTATE 1 836#define SQLITE_GET_LOCKPROXYFILE 2 837#define SQLITE_SET_LOCKPROXYFILE 3 838#define SQLITE_LAST_ERRNO 4 839#define SQLITE_FCNTL_SIZE_HINT 5 840#define SQLITE_FCNTL_CHUNK_SIZE 6 841#define SQLITE_FCNTL_FILE_POINTER 7 842#define SQLITE_FCNTL_SYNC_OMITTED 8 843#define SQLITE_FCNTL_WIN32_AV_RETRY 9 844#define SQLITE_FCNTL_PERSIST_WAL 10 845#define SQLITE_FCNTL_OVERWRITE 11 846#define SQLITE_FCNTL_VFSNAME 12 847#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 848#define SQLITE_FCNTL_PRAGMA 14 849 850/* 851** CAPI3REF: Mutex Handle 852** 853** The mutex module within SQLite defines [sqlite3_mutex] to be an 854** abstract type for a mutex object. The SQLite core never looks 855** at the internal representation of an [sqlite3_mutex]. It only 856** deals with pointers to the [sqlite3_mutex] object. 857** 858** Mutexes are created using [sqlite3_mutex_alloc()]. 859*/ 860typedef struct sqlite3_mutex sqlite3_mutex; 861 862/* 863** CAPI3REF: OS Interface Object 864** 865** An instance of the sqlite3_vfs object defines the interface between 866** the SQLite core and the underlying operating system. The "vfs" 867** in the name of the object stands for "virtual file system". See 868** the [VFS | VFS documentation] for further information. 869** 870** The value of the iVersion field is initially 1 but may be larger in 871** future versions of SQLite. Additional fields may be appended to this 872** object when the iVersion value is increased. Note that the structure 873** of the sqlite3_vfs object changes in the transaction between 874** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 875** modified. 876** 877** The szOsFile field is the size of the subclassed [sqlite3_file] 878** structure used by this VFS. mxPathname is the maximum length of 879** a pathname in this VFS. 880** 881** Registered sqlite3_vfs objects are kept on a linked list formed by 882** the pNext pointer. The [sqlite3_vfs_register()] 883** and [sqlite3_vfs_unregister()] interfaces manage this list 884** in a thread-safe way. The [sqlite3_vfs_find()] interface 885** searches the list. Neither the application code nor the VFS 886** implementation should use the pNext pointer. 887** 888** The pNext field is the only field in the sqlite3_vfs 889** structure that SQLite will ever modify. SQLite will only access 890** or modify this field while holding a particular static mutex. 891** The application should never modify anything within the sqlite3_vfs 892** object once the object has been registered. 893** 894** The zName field holds the name of the VFS module. The name must 895** be unique across all VFS modules. 896** 897** [[sqlite3_vfs.xOpen]] 898** ^SQLite guarantees that the zFilename parameter to xOpen 899** is either a NULL pointer or string obtained 900** from xFullPathname() with an optional suffix added. 901** ^If a suffix is added to the zFilename parameter, it will 902** consist of a single "-" character followed by no more than 903** 11 alphanumeric and/or "-" characters. 904** ^SQLite further guarantees that 905** the string will be valid and unchanged until xClose() is 906** called. Because of the previous sentence, 907** the [sqlite3_file] can safely store a pointer to the 908** filename if it needs to remember the filename for some reason. 909** If the zFilename parameter to xOpen is a NULL pointer then xOpen 910** must invent its own temporary name for the file. ^Whenever the 911** xFilename parameter is NULL it will also be the case that the 912** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 913** 914** The flags argument to xOpen() includes all bits set in 915** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 916** or [sqlite3_open16()] is used, then flags includes at least 917** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 918** If xOpen() opens a file read-only then it sets *pOutFlags to 919** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 920** 921** ^(SQLite will also add one of the following flags to the xOpen() 922** call, depending on the object being opened: 923** 924** <ul> 925** <li> [SQLITE_OPEN_MAIN_DB] 926** <li> [SQLITE_OPEN_MAIN_JOURNAL] 927** <li> [SQLITE_OPEN_TEMP_DB] 928** <li> [SQLITE_OPEN_TEMP_JOURNAL] 929** <li> [SQLITE_OPEN_TRANSIENT_DB] 930** <li> [SQLITE_OPEN_SUBJOURNAL] 931** <li> [SQLITE_OPEN_MASTER_JOURNAL] 932** <li> [SQLITE_OPEN_WAL] 933** </ul>)^ 934** 935** The file I/O implementation can use the object type flags to 936** change the way it deals with files. For example, an application 937** that does not care about crash recovery or rollback might make 938** the open of a journal file a no-op. Writes to this journal would 939** also be no-ops, and any attempt to read the journal would return 940** SQLITE_IOERR. Or the implementation might recognize that a database 941** file will be doing page-aligned sector reads and writes in a random 942** order and set up its I/O subsystem accordingly. 943** 944** SQLite might also add one of the following flags to the xOpen method: 945** 946** <ul> 947** <li> [SQLITE_OPEN_DELETEONCLOSE] 948** <li> [SQLITE_OPEN_EXCLUSIVE] 949** </ul> 950** 951** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 952** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 953** will be set for TEMP databases and their journals, transient 954** databases, and subjournals. 955** 956** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 957** with the [SQLITE_OPEN_CREATE] flag, which are both directly 958** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 959** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 960** SQLITE_OPEN_CREATE, is used to indicate that file should always 961** be created, and that it is an error if it already exists. 962** It is <i>not</i> used to indicate the file should be opened 963** for exclusive access. 964** 965** ^At least szOsFile bytes of memory are allocated by SQLite 966** to hold the [sqlite3_file] structure passed as the third 967** argument to xOpen. The xOpen method does not have to 968** allocate the structure; it should just fill it in. Note that 969** the xOpen method must set the sqlite3_file.pMethods to either 970** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 971** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 972** element will be valid after xOpen returns regardless of the success 973** or failure of the xOpen call. 974** 975** [[sqlite3_vfs.xAccess]] 976** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 977** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 978** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 979** to test whether a file is at least readable. The file can be a 980** directory. 981** 982** ^SQLite will always allocate at least mxPathname+1 bytes for the 983** output buffer xFullPathname. The exact size of the output buffer 984** is also passed as a parameter to both methods. If the output buffer 985** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 986** handled as a fatal error by SQLite, vfs implementations should endeavor 987** to prevent this by setting mxPathname to a sufficiently large value. 988** 989** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 990** interfaces are not strictly a part of the filesystem, but they are 991** included in the VFS structure for completeness. 992** The xRandomness() function attempts to return nBytes bytes 993** of good-quality randomness into zOut. The return value is 994** the actual number of bytes of randomness obtained. 995** The xSleep() method causes the calling thread to sleep for at 996** least the number of microseconds given. ^The xCurrentTime() 997** method returns a Julian Day Number for the current date and time as 998** a floating point value. 999** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1000** Day Number multiplied by 86400000 (the number of milliseconds in 1001** a 24-hour day). 1002** ^SQLite will use the xCurrentTimeInt64() method to get the current 1003** date and time if that method is available (if iVersion is 2 or 1004** greater and the function pointer is not NULL) and will fall back 1005** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1006** 1007** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1008** are not used by the SQLite core. These optional interfaces are provided 1009** by some VFSes to facilitate testing of the VFS code. By overriding 1010** system calls with functions under its control, a test program can 1011** simulate faults and error conditions that would otherwise be difficult 1012** or impossible to induce. The set of system calls that can be overridden 1013** varies from one VFS to another, and from one version of the same VFS to the 1014** next. Applications that use these interfaces must be prepared for any 1015** or all of these interfaces to be NULL or for their behavior to change 1016** from one release to the next. Applications must not attempt to access 1017** any of these methods if the iVersion of the VFS is less than 3. 1018*/ 1019typedef struct sqlite3_vfs sqlite3_vfs; 1020typedef void (*sqlite3_syscall_ptr)(void); 1021struct sqlite3_vfs { 1022 int iVersion; /* Structure version number (currently 3) */ 1023 int szOsFile; /* Size of subclassed sqlite3_file */ 1024 int mxPathname; /* Maximum file pathname length */ 1025 sqlite3_vfs *pNext; /* Next registered VFS */ 1026 const char *zName; /* Name of this virtual file system */ 1027 void *pAppData; /* Pointer to application-specific data */ 1028 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1029 int flags, int *pOutFlags); 1030 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1031 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1032 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1033 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1034 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1035 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1036 void (*xDlClose)(sqlite3_vfs*, void*); 1037 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1038 int (*xSleep)(sqlite3_vfs*, int microseconds); 1039 int (*xCurrentTime)(sqlite3_vfs*, double*); 1040 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1041 /* 1042 ** The methods above are in version 1 of the sqlite_vfs object 1043 ** definition. Those that follow are added in version 2 or later 1044 */ 1045 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1046 /* 1047 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1048 ** Those below are for version 3 and greater. 1049 */ 1050 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1051 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1052 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1053 /* 1054 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1055 ** New fields may be appended in figure versions. The iVersion 1056 ** value will increment whenever this happens. 1057 */ 1058}; 1059 1060/* 1061** CAPI3REF: Flags for the xAccess VFS method 1062** 1063** These integer constants can be used as the third parameter to 1064** the xAccess method of an [sqlite3_vfs] object. They determine 1065** what kind of permissions the xAccess method is looking for. 1066** With SQLITE_ACCESS_EXISTS, the xAccess method 1067** simply checks whether the file exists. 1068** With SQLITE_ACCESS_READWRITE, the xAccess method 1069** checks whether the named directory is both readable and writable 1070** (in other words, if files can be added, removed, and renamed within 1071** the directory). 1072** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1073** [temp_store_directory pragma], though this could change in a future 1074** release of SQLite. 1075** With SQLITE_ACCESS_READ, the xAccess method 1076** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1077** currently unused, though it might be used in a future release of 1078** SQLite. 1079*/ 1080#define SQLITE_ACCESS_EXISTS 0 1081#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1082#define SQLITE_ACCESS_READ 2 /* Unused */ 1083 1084/* 1085** CAPI3REF: Flags for the xShmLock VFS method 1086** 1087** These integer constants define the various locking operations 1088** allowed by the xShmLock method of [sqlite3_io_methods]. The 1089** following are the only legal combinations of flags to the 1090** xShmLock method: 1091** 1092** <ul> 1093** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1094** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1095** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1096** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1097** </ul> 1098** 1099** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1100** was given no the corresponding lock. 1101** 1102** The xShmLock method can transition between unlocked and SHARED or 1103** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1104** and EXCLUSIVE. 1105*/ 1106#define SQLITE_SHM_UNLOCK 1 1107#define SQLITE_SHM_LOCK 2 1108#define SQLITE_SHM_SHARED 4 1109#define SQLITE_SHM_EXCLUSIVE 8 1110 1111/* 1112** CAPI3REF: Maximum xShmLock index 1113** 1114** The xShmLock method on [sqlite3_io_methods] may use values 1115** between 0 and this upper bound as its "offset" argument. 1116** The SQLite core will never attempt to acquire or release a 1117** lock outside of this range 1118*/ 1119#define SQLITE_SHM_NLOCK 8 1120 1121 1122/* 1123** CAPI3REF: Initialize The SQLite Library 1124** 1125** ^The sqlite3_initialize() routine initializes the 1126** SQLite library. ^The sqlite3_shutdown() routine 1127** deallocates any resources that were allocated by sqlite3_initialize(). 1128** These routines are designed to aid in process initialization and 1129** shutdown on embedded systems. Workstation applications using 1130** SQLite normally do not need to invoke either of these routines. 1131** 1132** A call to sqlite3_initialize() is an "effective" call if it is 1133** the first time sqlite3_initialize() is invoked during the lifetime of 1134** the process, or if it is the first time sqlite3_initialize() is invoked 1135** following a call to sqlite3_shutdown(). ^(Only an effective call 1136** of sqlite3_initialize() does any initialization. All other calls 1137** are harmless no-ops.)^ 1138** 1139** A call to sqlite3_shutdown() is an "effective" call if it is the first 1140** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1141** an effective call to sqlite3_shutdown() does any deinitialization. 1142** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1143** 1144** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1145** is not. The sqlite3_shutdown() interface must only be called from a 1146** single thread. All open [database connections] must be closed and all 1147** other SQLite resources must be deallocated prior to invoking 1148** sqlite3_shutdown(). 1149** 1150** Among other things, ^sqlite3_initialize() will invoke 1151** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1152** will invoke sqlite3_os_end(). 1153** 1154** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1155** ^If for some reason, sqlite3_initialize() is unable to initialize 1156** the library (perhaps it is unable to allocate a needed resource such 1157** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1158** 1159** ^The sqlite3_initialize() routine is called internally by many other 1160** SQLite interfaces so that an application usually does not need to 1161** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1162** calls sqlite3_initialize() so the SQLite library will be automatically 1163** initialized when [sqlite3_open()] is called if it has not be initialized 1164** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1165** compile-time option, then the automatic calls to sqlite3_initialize() 1166** are omitted and the application must call sqlite3_initialize() directly 1167** prior to using any other SQLite interface. For maximum portability, 1168** it is recommended that applications always invoke sqlite3_initialize() 1169** directly prior to using any other SQLite interface. Future releases 1170** of SQLite may require this. In other words, the behavior exhibited 1171** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1172** default behavior in some future release of SQLite. 1173** 1174** The sqlite3_os_init() routine does operating-system specific 1175** initialization of the SQLite library. The sqlite3_os_end() 1176** routine undoes the effect of sqlite3_os_init(). Typical tasks 1177** performed by these routines include allocation or deallocation 1178** of static resources, initialization of global variables, 1179** setting up a default [sqlite3_vfs] module, or setting up 1180** a default configuration using [sqlite3_config()]. 1181** 1182** The application should never invoke either sqlite3_os_init() 1183** or sqlite3_os_end() directly. The application should only invoke 1184** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1185** interface is called automatically by sqlite3_initialize() and 1186** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1187** implementations for sqlite3_os_init() and sqlite3_os_end() 1188** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1189** When [custom builds | built for other platforms] 1190** (using the [SQLITE_OS_OTHER=1] compile-time 1191** option) the application must supply a suitable implementation for 1192** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1193** implementation of sqlite3_os_init() or sqlite3_os_end() 1194** must return [SQLITE_OK] on success and some other [error code] upon 1195** failure. 1196*/ 1197int sqlite3_initialize(void); 1198int sqlite3_shutdown(void); 1199int sqlite3_os_init(void); 1200int sqlite3_os_end(void); 1201 1202/* 1203** CAPI3REF: Configuring The SQLite Library 1204** 1205** The sqlite3_config() interface is used to make global configuration 1206** changes to SQLite in order to tune SQLite to the specific needs of 1207** the application. The default configuration is recommended for most 1208** applications and so this routine is usually not necessary. It is 1209** provided to support rare applications with unusual needs. 1210** 1211** The sqlite3_config() interface is not threadsafe. The application 1212** must insure that no other SQLite interfaces are invoked by other 1213** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1214** may only be invoked prior to library initialization using 1215** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1216** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1217** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1218** Note, however, that ^sqlite3_config() can be called as part of the 1219** implementation of an application-defined [sqlite3_os_init()]. 1220** 1221** The first argument to sqlite3_config() is an integer 1222** [configuration option] that determines 1223** what property of SQLite is to be configured. Subsequent arguments 1224** vary depending on the [configuration option] 1225** in the first argument. 1226** 1227** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1228** ^If the option is unknown or SQLite is unable to set the option 1229** then this routine returns a non-zero [error code]. 1230*/ 1231int sqlite3_config(int, ...); 1232 1233/* 1234** CAPI3REF: Configure database connections 1235** 1236** The sqlite3_db_config() interface is used to make configuration 1237** changes to a [database connection]. The interface is similar to 1238** [sqlite3_config()] except that the changes apply to a single 1239** [database connection] (specified in the first argument). 1240** 1241** The second argument to sqlite3_db_config(D,V,...) is the 1242** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1243** that indicates what aspect of the [database connection] is being configured. 1244** Subsequent arguments vary depending on the configuration verb. 1245** 1246** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1247** the call is considered successful. 1248*/ 1249int sqlite3_db_config(sqlite3*, int op, ...); 1250 1251/* 1252** CAPI3REF: Memory Allocation Routines 1253** 1254** An instance of this object defines the interface between SQLite 1255** and low-level memory allocation routines. 1256** 1257** This object is used in only one place in the SQLite interface. 1258** A pointer to an instance of this object is the argument to 1259** [sqlite3_config()] when the configuration option is 1260** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1261** By creating an instance of this object 1262** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1263** during configuration, an application can specify an alternative 1264** memory allocation subsystem for SQLite to use for all of its 1265** dynamic memory needs. 1266** 1267** Note that SQLite comes with several [built-in memory allocators] 1268** that are perfectly adequate for the overwhelming majority of applications 1269** and that this object is only useful to a tiny minority of applications 1270** with specialized memory allocation requirements. This object is 1271** also used during testing of SQLite in order to specify an alternative 1272** memory allocator that simulates memory out-of-memory conditions in 1273** order to verify that SQLite recovers gracefully from such 1274** conditions. 1275** 1276** The xMalloc, xRealloc, and xFree methods must work like the 1277** malloc(), realloc() and free() functions from the standard C library. 1278** ^SQLite guarantees that the second argument to 1279** xRealloc is always a value returned by a prior call to xRoundup. 1280** 1281** xSize should return the allocated size of a memory allocation 1282** previously obtained from xMalloc or xRealloc. The allocated size 1283** is always at least as big as the requested size but may be larger. 1284** 1285** The xRoundup method returns what would be the allocated size of 1286** a memory allocation given a particular requested size. Most memory 1287** allocators round up memory allocations at least to the next multiple 1288** of 8. Some allocators round up to a larger multiple or to a power of 2. 1289** Every memory allocation request coming in through [sqlite3_malloc()] 1290** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1291** that causes the corresponding memory allocation to fail. 1292** 1293** The xInit method initializes the memory allocator. (For example, 1294** it might allocate any require mutexes or initialize internal data 1295** structures. The xShutdown method is invoked (indirectly) by 1296** [sqlite3_shutdown()] and should deallocate any resources acquired 1297** by xInit. The pAppData pointer is used as the only parameter to 1298** xInit and xShutdown. 1299** 1300** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1301** the xInit method, so the xInit method need not be threadsafe. The 1302** xShutdown method is only called from [sqlite3_shutdown()] so it does 1303** not need to be threadsafe either. For all other methods, SQLite 1304** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1305** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1306** it is by default) and so the methods are automatically serialized. 1307** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1308** methods must be threadsafe or else make their own arrangements for 1309** serialization. 1310** 1311** SQLite will never invoke xInit() more than once without an intervening 1312** call to xShutdown(). 1313*/ 1314typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1315struct sqlite3_mem_methods { 1316 void *(*xMalloc)(int); /* Memory allocation function */ 1317 void (*xFree)(void*); /* Free a prior allocation */ 1318 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1319 int (*xSize)(void*); /* Return the size of an allocation */ 1320 int (*xRoundup)(int); /* Round up request size to allocation size */ 1321 int (*xInit)(void*); /* Initialize the memory allocator */ 1322 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1323 void *pAppData; /* Argument to xInit() and xShutdown() */ 1324}; 1325 1326/* 1327** CAPI3REF: Configuration Options 1328** KEYWORDS: {configuration option} 1329** 1330** These constants are the available integer configuration options that 1331** can be passed as the first argument to the [sqlite3_config()] interface. 1332** 1333** New configuration options may be added in future releases of SQLite. 1334** Existing configuration options might be discontinued. Applications 1335** should check the return code from [sqlite3_config()] to make sure that 1336** the call worked. The [sqlite3_config()] interface will return a 1337** non-zero [error code] if a discontinued or unsupported configuration option 1338** is invoked. 1339** 1340** <dl> 1341** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1342** <dd>There are no arguments to this option. ^This option sets the 1343** [threading mode] to Single-thread. In other words, it disables 1344** all mutexing and puts SQLite into a mode where it can only be used 1345** by a single thread. ^If SQLite is compiled with 1346** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1347** it is not possible to change the [threading mode] from its default 1348** value of Single-thread and so [sqlite3_config()] will return 1349** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1350** configuration option.</dd> 1351** 1352** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1353** <dd>There are no arguments to this option. ^This option sets the 1354** [threading mode] to Multi-thread. In other words, it disables 1355** mutexing on [database connection] and [prepared statement] objects. 1356** The application is responsible for serializing access to 1357** [database connections] and [prepared statements]. But other mutexes 1358** are enabled so that SQLite will be safe to use in a multi-threaded 1359** environment as long as no two threads attempt to use the same 1360** [database connection] at the same time. ^If SQLite is compiled with 1361** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1362** it is not possible to set the Multi-thread [threading mode] and 1363** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1364** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1365** 1366** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1367** <dd>There are no arguments to this option. ^This option sets the 1368** [threading mode] to Serialized. In other words, this option enables 1369** all mutexes including the recursive 1370** mutexes on [database connection] and [prepared statement] objects. 1371** In this mode (which is the default when SQLite is compiled with 1372** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1373** to [database connections] and [prepared statements] so that the 1374** application is free to use the same [database connection] or the 1375** same [prepared statement] in different threads at the same time. 1376** ^If SQLite is compiled with 1377** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1378** it is not possible to set the Serialized [threading mode] and 1379** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1380** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1381** 1382** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1383** <dd> ^(This option takes a single argument which is a pointer to an 1384** instance of the [sqlite3_mem_methods] structure. The argument specifies 1385** alternative low-level memory allocation routines to be used in place of 1386** the memory allocation routines built into SQLite.)^ ^SQLite makes 1387** its own private copy of the content of the [sqlite3_mem_methods] structure 1388** before the [sqlite3_config()] call returns.</dd> 1389** 1390** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1391** <dd> ^(This option takes a single argument which is a pointer to an 1392** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1393** structure is filled with the currently defined memory allocation routines.)^ 1394** This option can be used to overload the default memory allocation 1395** routines with a wrapper that simulations memory allocation failure or 1396** tracks memory usage, for example. </dd> 1397** 1398** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1399** <dd> ^This option takes single argument of type int, interpreted as a 1400** boolean, which enables or disables the collection of memory allocation 1401** statistics. ^(When memory allocation statistics are disabled, the 1402** following SQLite interfaces become non-operational: 1403** <ul> 1404** <li> [sqlite3_memory_used()] 1405** <li> [sqlite3_memory_highwater()] 1406** <li> [sqlite3_soft_heap_limit64()] 1407** <li> [sqlite3_status()] 1408** </ul>)^ 1409** ^Memory allocation statistics are enabled by default unless SQLite is 1410** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1411** allocation statistics are disabled by default. 1412** </dd> 1413** 1414** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1415** <dd> ^This option specifies a static memory buffer that SQLite can use for 1416** scratch memory. There are three arguments: A pointer an 8-byte 1417** aligned memory buffer from which the scratch allocations will be 1418** drawn, the size of each scratch allocation (sz), 1419** and the maximum number of scratch allocations (N). The sz 1420** argument must be a multiple of 16. 1421** The first argument must be a pointer to an 8-byte aligned buffer 1422** of at least sz*N bytes of memory. 1423** ^SQLite will use no more than two scratch buffers per thread. So 1424** N should be set to twice the expected maximum number of threads. 1425** ^SQLite will never require a scratch buffer that is more than 6 1426** times the database page size. ^If SQLite needs needs additional 1427** scratch memory beyond what is provided by this configuration option, then 1428** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1429** 1430** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1431** <dd> ^This option specifies a static memory buffer that SQLite can use for 1432** the database page cache with the default page cache implementation. 1433** This configuration should not be used if an application-define page 1434** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option. 1435** There are three arguments to this option: A pointer to 8-byte aligned 1436** memory, the size of each page buffer (sz), and the number of pages (N). 1437** The sz argument should be the size of the largest database page 1438** (a power of two between 512 and 32768) plus a little extra for each 1439** page header. ^The page header size is 20 to 40 bytes depending on 1440** the host architecture. ^It is harmless, apart from the wasted memory, 1441** to make sz a little too large. The first 1442** argument should point to an allocation of at least sz*N bytes of memory. 1443** ^SQLite will use the memory provided by the first argument to satisfy its 1444** memory needs for the first N pages that it adds to cache. ^If additional 1445** page cache memory is needed beyond what is provided by this option, then 1446** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1447** The pointer in the first argument must 1448** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1449** will be undefined.</dd> 1450** 1451** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1452** <dd> ^This option specifies a static memory buffer that SQLite will use 1453** for all of its dynamic memory allocation needs beyond those provided 1454** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1455** There are three arguments: An 8-byte aligned pointer to the memory, 1456** the number of bytes in the memory buffer, and the minimum allocation size. 1457** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1458** to using its default memory allocator (the system malloc() implementation), 1459** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1460** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1461** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1462** allocator is engaged to handle all of SQLites memory allocation needs. 1463** The first pointer (the memory pointer) must be aligned to an 8-byte 1464** boundary or subsequent behavior of SQLite will be undefined. 1465** The minimum allocation size is capped at 2**12. Reasonable values 1466** for the minimum allocation size are 2**5 through 2**8.</dd> 1467** 1468** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1469** <dd> ^(This option takes a single argument which is a pointer to an 1470** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1471** alternative low-level mutex routines to be used in place 1472** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1473** content of the [sqlite3_mutex_methods] structure before the call to 1474** [sqlite3_config()] returns. ^If SQLite is compiled with 1475** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1476** the entire mutexing subsystem is omitted from the build and hence calls to 1477** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1478** return [SQLITE_ERROR].</dd> 1479** 1480** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1481** <dd> ^(This option takes a single argument which is a pointer to an 1482** instance of the [sqlite3_mutex_methods] structure. The 1483** [sqlite3_mutex_methods] 1484** structure is filled with the currently defined mutex routines.)^ 1485** This option can be used to overload the default mutex allocation 1486** routines with a wrapper used to track mutex usage for performance 1487** profiling or testing, for example. ^If SQLite is compiled with 1488** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1489** the entire mutexing subsystem is omitted from the build and hence calls to 1490** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1491** return [SQLITE_ERROR].</dd> 1492** 1493** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1494** <dd> ^(This option takes two arguments that determine the default 1495** memory allocation for the lookaside memory allocator on each 1496** [database connection]. The first argument is the 1497** size of each lookaside buffer slot and the second is the number of 1498** slots allocated to each database connection.)^ ^(This option sets the 1499** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1500** verb to [sqlite3_db_config()] can be used to change the lookaside 1501** configuration on individual connections.)^ </dd> 1502** 1503** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1504** <dd> ^(This option takes a single argument which is a pointer to 1505** an [sqlite3_pcache_methods2] object. This object specifies the interface 1506** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1507** object and uses it for page cache memory allocations.</dd> 1508** 1509** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1510** <dd> ^(This option takes a single argument which is a pointer to an 1511** [sqlite3_pcache_methods2] object. SQLite copies of the current 1512** page cache implementation into that object.)^ </dd> 1513** 1514** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1515** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1516** function with a call signature of void(*)(void*,int,const char*), 1517** and a pointer to void. ^If the function pointer is not NULL, it is 1518** invoked by [sqlite3_log()] to process each logging event. ^If the 1519** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1520** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1521** passed through as the first parameter to the application-defined logger 1522** function whenever that function is invoked. ^The second parameter to 1523** the logger function is a copy of the first parameter to the corresponding 1524** [sqlite3_log()] call and is intended to be a [result code] or an 1525** [extended result code]. ^The third parameter passed to the logger is 1526** log message after formatting via [sqlite3_snprintf()]. 1527** The SQLite logging interface is not reentrant; the logger function 1528** supplied by the application must not invoke any SQLite interface. 1529** In a multi-threaded application, the application-defined logger 1530** function must be threadsafe. </dd> 1531** 1532** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1533** <dd> This option takes a single argument of type int. If non-zero, then 1534** URI handling is globally enabled. If the parameter is zero, then URI handling 1535** is globally disabled. If URI handling is globally enabled, all filenames 1536** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1537** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1538** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1539** connection is opened. If it is globally disabled, filenames are 1540** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1541** database connection is opened. By default, URI handling is globally 1542** disabled. The default value may be changed by compiling with the 1543** [SQLITE_USE_URI] symbol defined. 1544** 1545** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1546** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1547** <dd> These options are obsolete and should not be used by new code. 1548** They are retained for backwards compatibility but are now no-ops. 1549** </dl> 1550*/ 1551#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1552#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1553#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1554#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1555#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1556#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1557#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1558#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1559#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1560#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1561#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1562/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1563#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1564#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1565#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1566#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1567#define SQLITE_CONFIG_URI 17 /* int */ 1568#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1569#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1570 1571/* 1572** CAPI3REF: Database Connection Configuration Options 1573** 1574** These constants are the available integer configuration options that 1575** can be passed as the second argument to the [sqlite3_db_config()] interface. 1576** 1577** New configuration options may be added in future releases of SQLite. 1578** Existing configuration options might be discontinued. Applications 1579** should check the return code from [sqlite3_db_config()] to make sure that 1580** the call worked. ^The [sqlite3_db_config()] interface will return a 1581** non-zero [error code] if a discontinued or unsupported configuration option 1582** is invoked. 1583** 1584** <dl> 1585** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1586** <dd> ^This option takes three additional arguments that determine the 1587** [lookaside memory allocator] configuration for the [database connection]. 1588** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1589** pointer to a memory buffer to use for lookaside memory. 1590** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1591** may be NULL in which case SQLite will allocate the 1592** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1593** size of each lookaside buffer slot. ^The third argument is the number of 1594** slots. The size of the buffer in the first argument must be greater than 1595** or equal to the product of the second and third arguments. The buffer 1596** must be aligned to an 8-byte boundary. ^If the second argument to 1597** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1598** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1599** configuration for a database connection can only be changed when that 1600** connection is not currently using lookaside memory, or in other words 1601** when the "current value" returned by 1602** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1603** Any attempt to change the lookaside memory configuration when lookaside 1604** memory is in use leaves the configuration unchanged and returns 1605** [SQLITE_BUSY].)^</dd> 1606** 1607** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1608** <dd> ^This option is used to enable or disable the enforcement of 1609** [foreign key constraints]. There should be two additional arguments. 1610** The first argument is an integer which is 0 to disable FK enforcement, 1611** positive to enable FK enforcement or negative to leave FK enforcement 1612** unchanged. The second parameter is a pointer to an integer into which 1613** is written 0 or 1 to indicate whether FK enforcement is off or on 1614** following this call. The second parameter may be a NULL pointer, in 1615** which case the FK enforcement setting is not reported back. </dd> 1616** 1617** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1618** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1619** There should be two additional arguments. 1620** The first argument is an integer which is 0 to disable triggers, 1621** positive to enable triggers or negative to leave the setting unchanged. 1622** The second parameter is a pointer to an integer into which 1623** is written 0 or 1 to indicate whether triggers are disabled or enabled 1624** following this call. The second parameter may be a NULL pointer, in 1625** which case the trigger setting is not reported back. </dd> 1626** 1627** </dl> 1628*/ 1629#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1630#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1631#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1632 1633 1634/* 1635** CAPI3REF: Enable Or Disable Extended Result Codes 1636** 1637** ^The sqlite3_extended_result_codes() routine enables or disables the 1638** [extended result codes] feature of SQLite. ^The extended result 1639** codes are disabled by default for historical compatibility. 1640*/ 1641int sqlite3_extended_result_codes(sqlite3*, int onoff); 1642 1643/* 1644** CAPI3REF: Last Insert Rowid 1645** 1646** ^Each entry in an SQLite table has a unique 64-bit signed 1647** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1648** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1649** names are not also used by explicitly declared columns. ^If 1650** the table has a column of type [INTEGER PRIMARY KEY] then that column 1651** is another alias for the rowid. 1652** 1653** ^This routine returns the [rowid] of the most recent 1654** successful [INSERT] into the database from the [database connection] 1655** in the first argument. ^As of SQLite version 3.7.7, this routines 1656** records the last insert rowid of both ordinary tables and [virtual tables]. 1657** ^If no successful [INSERT]s 1658** have ever occurred on that database connection, zero is returned. 1659** 1660** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1661** method, then this routine will return the [rowid] of the inserted 1662** row as long as the trigger or virtual table method is running. 1663** But once the trigger or virtual table method ends, the value returned 1664** by this routine reverts to what it was before the trigger or virtual 1665** table method began.)^ 1666** 1667** ^An [INSERT] that fails due to a constraint violation is not a 1668** successful [INSERT] and does not change the value returned by this 1669** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1670** and INSERT OR ABORT make no changes to the return value of this 1671** routine when their insertion fails. ^(When INSERT OR REPLACE 1672** encounters a constraint violation, it does not fail. The 1673** INSERT continues to completion after deleting rows that caused 1674** the constraint problem so INSERT OR REPLACE will always change 1675** the return value of this interface.)^ 1676** 1677** ^For the purposes of this routine, an [INSERT] is considered to 1678** be successful even if it is subsequently rolled back. 1679** 1680** This function is accessible to SQL statements via the 1681** [last_insert_rowid() SQL function]. 1682** 1683** If a separate thread performs a new [INSERT] on the same 1684** database connection while the [sqlite3_last_insert_rowid()] 1685** function is running and thus changes the last insert [rowid], 1686** then the value returned by [sqlite3_last_insert_rowid()] is 1687** unpredictable and might not equal either the old or the new 1688** last insert [rowid]. 1689*/ 1690sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1691 1692/* 1693** CAPI3REF: Count The Number Of Rows Modified 1694** 1695** ^This function returns the number of database rows that were changed 1696** or inserted or deleted by the most recently completed SQL statement 1697** on the [database connection] specified by the first parameter. 1698** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1699** or [DELETE] statement are counted. Auxiliary changes caused by 1700** triggers or [foreign key actions] are not counted.)^ Use the 1701** [sqlite3_total_changes()] function to find the total number of changes 1702** including changes caused by triggers and foreign key actions. 1703** 1704** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1705** are not counted. Only real table changes are counted. 1706** 1707** ^(A "row change" is a change to a single row of a single table 1708** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1709** are changed as side effects of [REPLACE] constraint resolution, 1710** rollback, ABORT processing, [DROP TABLE], or by any other 1711** mechanisms do not count as direct row changes.)^ 1712** 1713** A "trigger context" is a scope of execution that begins and 1714** ends with the script of a [CREATE TRIGGER | trigger]. 1715** Most SQL statements are 1716** evaluated outside of any trigger. This is the "top level" 1717** trigger context. If a trigger fires from the top level, a 1718** new trigger context is entered for the duration of that one 1719** trigger. Subtriggers create subcontexts for their duration. 1720** 1721** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1722** not create a new trigger context. 1723** 1724** ^This function returns the number of direct row changes in the 1725** most recent INSERT, UPDATE, or DELETE statement within the same 1726** trigger context. 1727** 1728** ^Thus, when called from the top level, this function returns the 1729** number of changes in the most recent INSERT, UPDATE, or DELETE 1730** that also occurred at the top level. ^(Within the body of a trigger, 1731** the sqlite3_changes() interface can be called to find the number of 1732** changes in the most recently completed INSERT, UPDATE, or DELETE 1733** statement within the body of the same trigger. 1734** However, the number returned does not include changes 1735** caused by subtriggers since those have their own context.)^ 1736** 1737** See also the [sqlite3_total_changes()] interface, the 1738** [count_changes pragma], and the [changes() SQL function]. 1739** 1740** If a separate thread makes changes on the same database connection 1741** while [sqlite3_changes()] is running then the value returned 1742** is unpredictable and not meaningful. 1743*/ 1744int sqlite3_changes(sqlite3*); 1745 1746/* 1747** CAPI3REF: Total Number Of Rows Modified 1748** 1749** ^This function returns the number of row changes caused by [INSERT], 1750** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1751** ^(The count returned by sqlite3_total_changes() includes all changes 1752** from all [CREATE TRIGGER | trigger] contexts and changes made by 1753** [foreign key actions]. However, 1754** the count does not include changes used to implement [REPLACE] constraints, 1755** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1756** count does not include rows of views that fire an [INSTEAD OF trigger], 1757** though if the INSTEAD OF trigger makes changes of its own, those changes 1758** are counted.)^ 1759** ^The sqlite3_total_changes() function counts the changes as soon as 1760** the statement that makes them is completed (when the statement handle 1761** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1762** 1763** See also the [sqlite3_changes()] interface, the 1764** [count_changes pragma], and the [total_changes() SQL function]. 1765** 1766** If a separate thread makes changes on the same database connection 1767** while [sqlite3_total_changes()] is running then the value 1768** returned is unpredictable and not meaningful. 1769*/ 1770int sqlite3_total_changes(sqlite3*); 1771 1772/* 1773** CAPI3REF: Interrupt A Long-Running Query 1774** 1775** ^This function causes any pending database operation to abort and 1776** return at its earliest opportunity. This routine is typically 1777** called in response to a user action such as pressing "Cancel" 1778** or Ctrl-C where the user wants a long query operation to halt 1779** immediately. 1780** 1781** ^It is safe to call this routine from a thread different from the 1782** thread that is currently running the database operation. But it 1783** is not safe to call this routine with a [database connection] that 1784** is closed or might close before sqlite3_interrupt() returns. 1785** 1786** ^If an SQL operation is very nearly finished at the time when 1787** sqlite3_interrupt() is called, then it might not have an opportunity 1788** to be interrupted and might continue to completion. 1789** 1790** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1791** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1792** that is inside an explicit transaction, then the entire transaction 1793** will be rolled back automatically. 1794** 1795** ^The sqlite3_interrupt(D) call is in effect until all currently running 1796** SQL statements on [database connection] D complete. ^Any new SQL statements 1797** that are started after the sqlite3_interrupt() call and before the 1798** running statements reaches zero are interrupted as if they had been 1799** running prior to the sqlite3_interrupt() call. ^New SQL statements 1800** that are started after the running statement count reaches zero are 1801** not effected by the sqlite3_interrupt(). 1802** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1803** SQL statements is a no-op and has no effect on SQL statements 1804** that are started after the sqlite3_interrupt() call returns. 1805** 1806** If the database connection closes while [sqlite3_interrupt()] 1807** is running then bad things will likely happen. 1808*/ 1809void sqlite3_interrupt(sqlite3*); 1810 1811/* 1812** CAPI3REF: Determine If An SQL Statement Is Complete 1813** 1814** These routines are useful during command-line input to determine if the 1815** currently entered text seems to form a complete SQL statement or 1816** if additional input is needed before sending the text into 1817** SQLite for parsing. ^These routines return 1 if the input string 1818** appears to be a complete SQL statement. ^A statement is judged to be 1819** complete if it ends with a semicolon token and is not a prefix of a 1820** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1821** string literals or quoted identifier names or comments are not 1822** independent tokens (they are part of the token in which they are 1823** embedded) and thus do not count as a statement terminator. ^Whitespace 1824** and comments that follow the final semicolon are ignored. 1825** 1826** ^These routines return 0 if the statement is incomplete. ^If a 1827** memory allocation fails, then SQLITE_NOMEM is returned. 1828** 1829** ^These routines do not parse the SQL statements thus 1830** will not detect syntactically incorrect SQL. 1831** 1832** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1833** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1834** automatically by sqlite3_complete16(). If that initialization fails, 1835** then the return value from sqlite3_complete16() will be non-zero 1836** regardless of whether or not the input SQL is complete.)^ 1837** 1838** The input to [sqlite3_complete()] must be a zero-terminated 1839** UTF-8 string. 1840** 1841** The input to [sqlite3_complete16()] must be a zero-terminated 1842** UTF-16 string in native byte order. 1843*/ 1844int sqlite3_complete(const char *sql); 1845int sqlite3_complete16(const void *sql); 1846 1847/* 1848** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1849** 1850** ^This routine sets a callback function that might be invoked whenever 1851** an attempt is made to open a database table that another thread 1852** or process has locked. 1853** 1854** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1855** is returned immediately upon encountering the lock. ^If the busy callback 1856** is not NULL, then the callback might be invoked with two arguments. 1857** 1858** ^The first argument to the busy handler is a copy of the void* pointer which 1859** is the third argument to sqlite3_busy_handler(). ^The second argument to 1860** the busy handler callback is the number of times that the busy handler has 1861** been invoked for this locking event. ^If the 1862** busy callback returns 0, then no additional attempts are made to 1863** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1864** ^If the callback returns non-zero, then another attempt 1865** is made to open the database for reading and the cycle repeats. 1866** 1867** The presence of a busy handler does not guarantee that it will be invoked 1868** when there is lock contention. ^If SQLite determines that invoking the busy 1869** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1870** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1871** Consider a scenario where one process is holding a read lock that 1872** it is trying to promote to a reserved lock and 1873** a second process is holding a reserved lock that it is trying 1874** to promote to an exclusive lock. The first process cannot proceed 1875** because it is blocked by the second and the second process cannot 1876** proceed because it is blocked by the first. If both processes 1877** invoke the busy handlers, neither will make any progress. Therefore, 1878** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1879** will induce the first process to release its read lock and allow 1880** the second process to proceed. 1881** 1882** ^The default busy callback is NULL. 1883** 1884** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1885** when SQLite is in the middle of a large transaction where all the 1886** changes will not fit into the in-memory cache. SQLite will 1887** already hold a RESERVED lock on the database file, but it needs 1888** to promote this lock to EXCLUSIVE so that it can spill cache 1889** pages into the database file without harm to concurrent 1890** readers. ^If it is unable to promote the lock, then the in-memory 1891** cache will be left in an inconsistent state and so the error 1892** code is promoted from the relatively benign [SQLITE_BUSY] to 1893** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1894** forces an automatic rollback of the changes. See the 1895** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1896** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1897** this is important. 1898** 1899** ^(There can only be a single busy handler defined for each 1900** [database connection]. Setting a new busy handler clears any 1901** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1902** will also set or clear the busy handler. 1903** 1904** The busy callback should not take any actions which modify the 1905** database connection that invoked the busy handler. Any such actions 1906** result in undefined behavior. 1907** 1908** A busy handler must not close the database connection 1909** or [prepared statement] that invoked the busy handler. 1910*/ 1911int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1912 1913/* 1914** CAPI3REF: Set A Busy Timeout 1915** 1916** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1917** for a specified amount of time when a table is locked. ^The handler 1918** will sleep multiple times until at least "ms" milliseconds of sleeping 1919** have accumulated. ^After at least "ms" milliseconds of sleeping, 1920** the handler returns 0 which causes [sqlite3_step()] to return 1921** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1922** 1923** ^Calling this routine with an argument less than or equal to zero 1924** turns off all busy handlers. 1925** 1926** ^(There can only be a single busy handler for a particular 1927** [database connection] any any given moment. If another busy handler 1928** was defined (using [sqlite3_busy_handler()]) prior to calling 1929** this routine, that other busy handler is cleared.)^ 1930*/ 1931int sqlite3_busy_timeout(sqlite3*, int ms); 1932 1933/* 1934** CAPI3REF: Convenience Routines For Running Queries 1935** 1936** This is a legacy interface that is preserved for backwards compatibility. 1937** Use of this interface is not recommended. 1938** 1939** Definition: A <b>result table</b> is memory data structure created by the 1940** [sqlite3_get_table()] interface. A result table records the 1941** complete query results from one or more queries. 1942** 1943** The table conceptually has a number of rows and columns. But 1944** these numbers are not part of the result table itself. These 1945** numbers are obtained separately. Let N be the number of rows 1946** and M be the number of columns. 1947** 1948** A result table is an array of pointers to zero-terminated UTF-8 strings. 1949** There are (N+1)*M elements in the array. The first M pointers point 1950** to zero-terminated strings that contain the names of the columns. 1951** The remaining entries all point to query results. NULL values result 1952** in NULL pointers. All other values are in their UTF-8 zero-terminated 1953** string representation as returned by [sqlite3_column_text()]. 1954** 1955** A result table might consist of one or more memory allocations. 1956** It is not safe to pass a result table directly to [sqlite3_free()]. 1957** A result table should be deallocated using [sqlite3_free_table()]. 1958** 1959** ^(As an example of the result table format, suppose a query result 1960** is as follows: 1961** 1962** <blockquote><pre> 1963** Name | Age 1964** ----------------------- 1965** Alice | 43 1966** Bob | 28 1967** Cindy | 21 1968** </pre></blockquote> 1969** 1970** There are two column (M==2) and three rows (N==3). Thus the 1971** result table has 8 entries. Suppose the result table is stored 1972** in an array names azResult. Then azResult holds this content: 1973** 1974** <blockquote><pre> 1975** azResult[0] = "Name"; 1976** azResult[1] = "Age"; 1977** azResult[2] = "Alice"; 1978** azResult[3] = "43"; 1979** azResult[4] = "Bob"; 1980** azResult[5] = "28"; 1981** azResult[6] = "Cindy"; 1982** azResult[7] = "21"; 1983** </pre></blockquote>)^ 1984** 1985** ^The sqlite3_get_table() function evaluates one or more 1986** semicolon-separated SQL statements in the zero-terminated UTF-8 1987** string of its 2nd parameter and returns a result table to the 1988** pointer given in its 3rd parameter. 1989** 1990** After the application has finished with the result from sqlite3_get_table(), 1991** it must pass the result table pointer to sqlite3_free_table() in order to 1992** release the memory that was malloced. Because of the way the 1993** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1994** function must not try to call [sqlite3_free()] directly. Only 1995** [sqlite3_free_table()] is able to release the memory properly and safely. 1996** 1997** The sqlite3_get_table() interface is implemented as a wrapper around 1998** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1999** to any internal data structures of SQLite. It uses only the public 2000** interface defined here. As a consequence, errors that occur in the 2001** wrapper layer outside of the internal [sqlite3_exec()] call are not 2002** reflected in subsequent calls to [sqlite3_errcode()] or 2003** [sqlite3_errmsg()]. 2004*/ 2005int sqlite3_get_table( 2006 sqlite3 *db, /* An open database */ 2007 const char *zSql, /* SQL to be evaluated */ 2008 char ***pazResult, /* Results of the query */ 2009 int *pnRow, /* Number of result rows written here */ 2010 int *pnColumn, /* Number of result columns written here */ 2011 char **pzErrmsg /* Error msg written here */ 2012); 2013void sqlite3_free_table(char **result); 2014 2015/* 2016** CAPI3REF: Formatted String Printing Functions 2017** 2018** These routines are work-alikes of the "printf()" family of functions 2019** from the standard C library. 2020** 2021** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2022** results into memory obtained from [sqlite3_malloc()]. 2023** The strings returned by these two routines should be 2024** released by [sqlite3_free()]. ^Both routines return a 2025** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2026** memory to hold the resulting string. 2027** 2028** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2029** the standard C library. The result is written into the 2030** buffer supplied as the second parameter whose size is given by 2031** the first parameter. Note that the order of the 2032** first two parameters is reversed from snprintf().)^ This is an 2033** historical accident that cannot be fixed without breaking 2034** backwards compatibility. ^(Note also that sqlite3_snprintf() 2035** returns a pointer to its buffer instead of the number of 2036** characters actually written into the buffer.)^ We admit that 2037** the number of characters written would be a more useful return 2038** value but we cannot change the implementation of sqlite3_snprintf() 2039** now without breaking compatibility. 2040** 2041** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2042** guarantees that the buffer is always zero-terminated. ^The first 2043** parameter "n" is the total size of the buffer, including space for 2044** the zero terminator. So the longest string that can be completely 2045** written will be n-1 characters. 2046** 2047** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2048** 2049** These routines all implement some additional formatting 2050** options that are useful for constructing SQL statements. 2051** All of the usual printf() formatting options apply. In addition, there 2052** is are "%q", "%Q", and "%z" options. 2053** 2054** ^(The %q option works like %s in that it substitutes a nul-terminated 2055** string from the argument list. But %q also doubles every '\'' character. 2056** %q is designed for use inside a string literal.)^ By doubling each '\'' 2057** character it escapes that character and allows it to be inserted into 2058** the string. 2059** 2060** For example, assume the string variable zText contains text as follows: 2061** 2062** <blockquote><pre> 2063** char *zText = "It's a happy day!"; 2064** </pre></blockquote> 2065** 2066** One can use this text in an SQL statement as follows: 2067** 2068** <blockquote><pre> 2069** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2070** sqlite3_exec(db, zSQL, 0, 0, 0); 2071** sqlite3_free(zSQL); 2072** </pre></blockquote> 2073** 2074** Because the %q format string is used, the '\'' character in zText 2075** is escaped and the SQL generated is as follows: 2076** 2077** <blockquote><pre> 2078** INSERT INTO table1 VALUES('It''s a happy day!') 2079** </pre></blockquote> 2080** 2081** This is correct. Had we used %s instead of %q, the generated SQL 2082** would have looked like this: 2083** 2084** <blockquote><pre> 2085** INSERT INTO table1 VALUES('It's a happy day!'); 2086** </pre></blockquote> 2087** 2088** This second example is an SQL syntax error. As a general rule you should 2089** always use %q instead of %s when inserting text into a string literal. 2090** 2091** ^(The %Q option works like %q except it also adds single quotes around 2092** the outside of the total string. Additionally, if the parameter in the 2093** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2094** single quotes).)^ So, for example, one could say: 2095** 2096** <blockquote><pre> 2097** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2098** sqlite3_exec(db, zSQL, 0, 0, 0); 2099** sqlite3_free(zSQL); 2100** </pre></blockquote> 2101** 2102** The code above will render a correct SQL statement in the zSQL 2103** variable even if the zText variable is a NULL pointer. 2104** 2105** ^(The "%z" formatting option works like "%s" but with the 2106** addition that after the string has been read and copied into 2107** the result, [sqlite3_free()] is called on the input string.)^ 2108*/ 2109char *sqlite3_mprintf(const char*,...); 2110char *sqlite3_vmprintf(const char*, va_list); 2111char *sqlite3_snprintf(int,char*,const char*, ...); 2112char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2113 2114/* 2115** CAPI3REF: Memory Allocation Subsystem 2116** 2117** The SQLite core uses these three routines for all of its own 2118** internal memory allocation needs. "Core" in the previous sentence 2119** does not include operating-system specific VFS implementation. The 2120** Windows VFS uses native malloc() and free() for some operations. 2121** 2122** ^The sqlite3_malloc() routine returns a pointer to a block 2123** of memory at least N bytes in length, where N is the parameter. 2124** ^If sqlite3_malloc() is unable to obtain sufficient free 2125** memory, it returns a NULL pointer. ^If the parameter N to 2126** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2127** a NULL pointer. 2128** 2129** ^Calling sqlite3_free() with a pointer previously returned 2130** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2131** that it might be reused. ^The sqlite3_free() routine is 2132** a no-op if is called with a NULL pointer. Passing a NULL pointer 2133** to sqlite3_free() is harmless. After being freed, memory 2134** should neither be read nor written. Even reading previously freed 2135** memory might result in a segmentation fault or other severe error. 2136** Memory corruption, a segmentation fault, or other severe error 2137** might result if sqlite3_free() is called with a non-NULL pointer that 2138** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2139** 2140** ^(The sqlite3_realloc() interface attempts to resize a 2141** prior memory allocation to be at least N bytes, where N is the 2142** second parameter. The memory allocation to be resized is the first 2143** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2144** is a NULL pointer then its behavior is identical to calling 2145** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2146** ^If the second parameter to sqlite3_realloc() is zero or 2147** negative then the behavior is exactly the same as calling 2148** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2149** ^sqlite3_realloc() returns a pointer to a memory allocation 2150** of at least N bytes in size or NULL if sufficient memory is unavailable. 2151** ^If M is the size of the prior allocation, then min(N,M) bytes 2152** of the prior allocation are copied into the beginning of buffer returned 2153** by sqlite3_realloc() and the prior allocation is freed. 2154** ^If sqlite3_realloc() returns NULL, then the prior allocation 2155** is not freed. 2156** 2157** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2158** is always aligned to at least an 8 byte boundary, or to a 2159** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2160** option is used. 2161** 2162** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2163** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2164** implementation of these routines to be omitted. That capability 2165** is no longer provided. Only built-in memory allocators can be used. 2166** 2167** The Windows OS interface layer calls 2168** the system malloc() and free() directly when converting 2169** filenames between the UTF-8 encoding used by SQLite 2170** and whatever filename encoding is used by the particular Windows 2171** installation. Memory allocation errors are detected, but 2172** they are reported back as [SQLITE_CANTOPEN] or 2173** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2174** 2175** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2176** must be either NULL or else pointers obtained from a prior 2177** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2178** not yet been released. 2179** 2180** The application must not read or write any part of 2181** a block of memory after it has been released using 2182** [sqlite3_free()] or [sqlite3_realloc()]. 2183*/ 2184void *sqlite3_malloc(int); 2185void *sqlite3_realloc(void*, int); 2186void sqlite3_free(void*); 2187 2188/* 2189** CAPI3REF: Memory Allocator Statistics 2190** 2191** SQLite provides these two interfaces for reporting on the status 2192** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2193** routines, which form the built-in memory allocation subsystem. 2194** 2195** ^The [sqlite3_memory_used()] routine returns the number of bytes 2196** of memory currently outstanding (malloced but not freed). 2197** ^The [sqlite3_memory_highwater()] routine returns the maximum 2198** value of [sqlite3_memory_used()] since the high-water mark 2199** was last reset. ^The values returned by [sqlite3_memory_used()] and 2200** [sqlite3_memory_highwater()] include any overhead 2201** added by SQLite in its implementation of [sqlite3_malloc()], 2202** but not overhead added by the any underlying system library 2203** routines that [sqlite3_malloc()] may call. 2204** 2205** ^The memory high-water mark is reset to the current value of 2206** [sqlite3_memory_used()] if and only if the parameter to 2207** [sqlite3_memory_highwater()] is true. ^The value returned 2208** by [sqlite3_memory_highwater(1)] is the high-water mark 2209** prior to the reset. 2210*/ 2211sqlite3_int64 sqlite3_memory_used(void); 2212sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2213 2214/* 2215** CAPI3REF: Pseudo-Random Number Generator 2216** 2217** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2218** select random [ROWID | ROWIDs] when inserting new records into a table that 2219** already uses the largest possible [ROWID]. The PRNG is also used for 2220** the build-in random() and randomblob() SQL functions. This interface allows 2221** applications to access the same PRNG for other purposes. 2222** 2223** ^A call to this routine stores N bytes of randomness into buffer P. 2224** 2225** ^The first time this routine is invoked (either internally or by 2226** the application) the PRNG is seeded using randomness obtained 2227** from the xRandomness method of the default [sqlite3_vfs] object. 2228** ^On all subsequent invocations, the pseudo-randomness is generated 2229** internally and without recourse to the [sqlite3_vfs] xRandomness 2230** method. 2231*/ 2232void sqlite3_randomness(int N, void *P); 2233 2234/* 2235** CAPI3REF: Compile-Time Authorization Callbacks 2236** 2237** ^This routine registers an authorizer callback with a particular 2238** [database connection], supplied in the first argument. 2239** ^The authorizer callback is invoked as SQL statements are being compiled 2240** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2241** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2242** points during the compilation process, as logic is being created 2243** to perform various actions, the authorizer callback is invoked to 2244** see if those actions are allowed. ^The authorizer callback should 2245** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2246** specific action but allow the SQL statement to continue to be 2247** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2248** rejected with an error. ^If the authorizer callback returns 2249** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2250** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2251** the authorizer will fail with an error message. 2252** 2253** When the callback returns [SQLITE_OK], that means the operation 2254** requested is ok. ^When the callback returns [SQLITE_DENY], the 2255** [sqlite3_prepare_v2()] or equivalent call that triggered the 2256** authorizer will fail with an error message explaining that 2257** access is denied. 2258** 2259** ^The first parameter to the authorizer callback is a copy of the third 2260** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2261** to the callback is an integer [SQLITE_COPY | action code] that specifies 2262** the particular action to be authorized. ^The third through sixth parameters 2263** to the callback are zero-terminated strings that contain additional 2264** details about the action to be authorized. 2265** 2266** ^If the action code is [SQLITE_READ] 2267** and the callback returns [SQLITE_IGNORE] then the 2268** [prepared statement] statement is constructed to substitute 2269** a NULL value in place of the table column that would have 2270** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2271** return can be used to deny an untrusted user access to individual 2272** columns of a table. 2273** ^If the action code is [SQLITE_DELETE] and the callback returns 2274** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2275** [truncate optimization] is disabled and all rows are deleted individually. 2276** 2277** An authorizer is used when [sqlite3_prepare | preparing] 2278** SQL statements from an untrusted source, to ensure that the SQL statements 2279** do not try to access data they are not allowed to see, or that they do not 2280** try to execute malicious statements that damage the database. For 2281** example, an application may allow a user to enter arbitrary 2282** SQL queries for evaluation by a database. But the application does 2283** not want the user to be able to make arbitrary changes to the 2284** database. An authorizer could then be put in place while the 2285** user-entered SQL is being [sqlite3_prepare | prepared] that 2286** disallows everything except [SELECT] statements. 2287** 2288** Applications that need to process SQL from untrusted sources 2289** might also consider lowering resource limits using [sqlite3_limit()] 2290** and limiting database size using the [max_page_count] [PRAGMA] 2291** in addition to using an authorizer. 2292** 2293** ^(Only a single authorizer can be in place on a database connection 2294** at a time. Each call to sqlite3_set_authorizer overrides the 2295** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2296** The authorizer is disabled by default. 2297** 2298** The authorizer callback must not do anything that will modify 2299** the database connection that invoked the authorizer callback. 2300** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2301** database connections for the meaning of "modify" in this paragraph. 2302** 2303** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2304** statement might be re-prepared during [sqlite3_step()] due to a 2305** schema change. Hence, the application should ensure that the 2306** correct authorizer callback remains in place during the [sqlite3_step()]. 2307** 2308** ^Note that the authorizer callback is invoked only during 2309** [sqlite3_prepare()] or its variants. Authorization is not 2310** performed during statement evaluation in [sqlite3_step()], unless 2311** as stated in the previous paragraph, sqlite3_step() invokes 2312** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2313*/ 2314int sqlite3_set_authorizer( 2315 sqlite3*, 2316 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2317 void *pUserData 2318); 2319 2320/* 2321** CAPI3REF: Authorizer Return Codes 2322** 2323** The [sqlite3_set_authorizer | authorizer callback function] must 2324** return either [SQLITE_OK] or one of these two constants in order 2325** to signal SQLite whether or not the action is permitted. See the 2326** [sqlite3_set_authorizer | authorizer documentation] for additional 2327** information. 2328** 2329** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2330** from the [sqlite3_vtab_on_conflict()] interface. 2331*/ 2332#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2333#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2334 2335/* 2336** CAPI3REF: Authorizer Action Codes 2337** 2338** The [sqlite3_set_authorizer()] interface registers a callback function 2339** that is invoked to authorize certain SQL statement actions. The 2340** second parameter to the callback is an integer code that specifies 2341** what action is being authorized. These are the integer action codes that 2342** the authorizer callback may be passed. 2343** 2344** These action code values signify what kind of operation is to be 2345** authorized. The 3rd and 4th parameters to the authorization 2346** callback function will be parameters or NULL depending on which of these 2347** codes is used as the second parameter. ^(The 5th parameter to the 2348** authorizer callback is the name of the database ("main", "temp", 2349** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2350** is the name of the inner-most trigger or view that is responsible for 2351** the access attempt or NULL if this access attempt is directly from 2352** top-level SQL code. 2353*/ 2354/******************************************* 3rd ************ 4th ***********/ 2355#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2356#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2357#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2358#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2359#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2360#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2361#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2362#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2363#define SQLITE_DELETE 9 /* Table Name NULL */ 2364#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2365#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2366#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2367#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2368#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2369#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2370#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2371#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2372#define SQLITE_INSERT 18 /* Table Name NULL */ 2373#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2374#define SQLITE_READ 20 /* Table Name Column Name */ 2375#define SQLITE_SELECT 21 /* NULL NULL */ 2376#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2377#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2378#define SQLITE_ATTACH 24 /* Filename NULL */ 2379#define SQLITE_DETACH 25 /* Database Name NULL */ 2380#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2381#define SQLITE_REINDEX 27 /* Index Name NULL */ 2382#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2383#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2384#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2385#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2386#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2387#define SQLITE_COPY 0 /* No longer used */ 2388 2389/* 2390** CAPI3REF: Tracing And Profiling Functions 2391** 2392** These routines register callback functions that can be used for 2393** tracing and profiling the execution of SQL statements. 2394** 2395** ^The callback function registered by sqlite3_trace() is invoked at 2396** various times when an SQL statement is being run by [sqlite3_step()]. 2397** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2398** SQL statement text as the statement first begins executing. 2399** ^(Additional sqlite3_trace() callbacks might occur 2400** as each triggered subprogram is entered. The callbacks for triggers 2401** contain a UTF-8 SQL comment that identifies the trigger.)^ 2402** 2403** ^The callback function registered by sqlite3_profile() is invoked 2404** as each SQL statement finishes. ^The profile callback contains 2405** the original statement text and an estimate of wall-clock time 2406** of how long that statement took to run. ^The profile callback 2407** time is in units of nanoseconds, however the current implementation 2408** is only capable of millisecond resolution so the six least significant 2409** digits in the time are meaningless. Future versions of SQLite 2410** might provide greater resolution on the profiler callback. The 2411** sqlite3_profile() function is considered experimental and is 2412** subject to change in future versions of SQLite. 2413*/ 2414void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2415SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2416 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2417 2418/* 2419** CAPI3REF: Query Progress Callbacks 2420** 2421** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2422** function X to be invoked periodically during long running calls to 2423** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2424** database connection D. An example use for this 2425** interface is to keep a GUI updated during a large query. 2426** 2427** ^The parameter P is passed through as the only parameter to the 2428** callback function X. ^The parameter N is the number of 2429** [virtual machine instructions] that are evaluated between successive 2430** invocations of the callback X. 2431** 2432** ^Only a single progress handler may be defined at one time per 2433** [database connection]; setting a new progress handler cancels the 2434** old one. ^Setting parameter X to NULL disables the progress handler. 2435** ^The progress handler is also disabled by setting N to a value less 2436** than 1. 2437** 2438** ^If the progress callback returns non-zero, the operation is 2439** interrupted. This feature can be used to implement a 2440** "Cancel" button on a GUI progress dialog box. 2441** 2442** The progress handler callback must not do anything that will modify 2443** the database connection that invoked the progress handler. 2444** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2445** database connections for the meaning of "modify" in this paragraph. 2446** 2447*/ 2448void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2449 2450/* 2451** CAPI3REF: Opening A New Database Connection 2452** 2453** ^These routines open an SQLite database file as specified by the 2454** filename argument. ^The filename argument is interpreted as UTF-8 for 2455** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2456** order for sqlite3_open16(). ^(A [database connection] handle is usually 2457** returned in *ppDb, even if an error occurs. The only exception is that 2458** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2459** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2460** object.)^ ^(If the database is opened (and/or created) successfully, then 2461** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2462** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2463** an English language description of the error following a failure of any 2464** of the sqlite3_open() routines. 2465** 2466** ^The default encoding for the database will be UTF-8 if 2467** sqlite3_open() or sqlite3_open_v2() is called and 2468** UTF-16 in the native byte order if sqlite3_open16() is used. 2469** 2470** Whether or not an error occurs when it is opened, resources 2471** associated with the [database connection] handle should be released by 2472** passing it to [sqlite3_close()] when it is no longer required. 2473** 2474** The sqlite3_open_v2() interface works like sqlite3_open() 2475** except that it accepts two additional parameters for additional control 2476** over the new database connection. ^(The flags parameter to 2477** sqlite3_open_v2() can take one of 2478** the following three values, optionally combined with the 2479** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2480** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2481** 2482** <dl> 2483** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2484** <dd>The database is opened in read-only mode. If the database does not 2485** already exist, an error is returned.</dd>)^ 2486** 2487** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2488** <dd>The database is opened for reading and writing if possible, or reading 2489** only if the file is write protected by the operating system. In either 2490** case the database must already exist, otherwise an error is returned.</dd>)^ 2491** 2492** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2493** <dd>The database is opened for reading and writing, and is created if 2494** it does not already exist. This is the behavior that is always used for 2495** sqlite3_open() and sqlite3_open16().</dd>)^ 2496** </dl> 2497** 2498** If the 3rd parameter to sqlite3_open_v2() is not one of the 2499** combinations shown above optionally combined with other 2500** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2501** then the behavior is undefined. 2502** 2503** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2504** opens in the multi-thread [threading mode] as long as the single-thread 2505** mode has not been set at compile-time or start-time. ^If the 2506** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2507** in the serialized [threading mode] unless single-thread was 2508** previously selected at compile-time or start-time. 2509** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2510** eligible to use [shared cache mode], regardless of whether or not shared 2511** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2512** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2513** participate in [shared cache mode] even if it is enabled. 2514** 2515** ^The fourth parameter to sqlite3_open_v2() is the name of the 2516** [sqlite3_vfs] object that defines the operating system interface that 2517** the new database connection should use. ^If the fourth parameter is 2518** a NULL pointer then the default [sqlite3_vfs] object is used. 2519** 2520** ^If the filename is ":memory:", then a private, temporary in-memory database 2521** is created for the connection. ^This in-memory database will vanish when 2522** the database connection is closed. Future versions of SQLite might 2523** make use of additional special filenames that begin with the ":" character. 2524** It is recommended that when a database filename actually does begin with 2525** a ":" character you should prefix the filename with a pathname such as 2526** "./" to avoid ambiguity. 2527** 2528** ^If the filename is an empty string, then a private, temporary 2529** on-disk database will be created. ^This private database will be 2530** automatically deleted as soon as the database connection is closed. 2531** 2532** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2533** 2534** ^If [URI filename] interpretation is enabled, and the filename argument 2535** begins with "file:", then the filename is interpreted as a URI. ^URI 2536** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2537** set in the fourth argument to sqlite3_open_v2(), or if it has 2538** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2539** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2540** As of SQLite version 3.7.7, URI filename interpretation is turned off 2541** by default, but future releases of SQLite might enable URI filename 2542** interpretation by default. See "[URI filenames]" for additional 2543** information. 2544** 2545** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2546** authority, then it must be either an empty string or the string 2547** "localhost". ^If the authority is not an empty string or "localhost", an 2548** error is returned to the caller. ^The fragment component of a URI, if 2549** present, is ignored. 2550** 2551** ^SQLite uses the path component of the URI as the name of the disk file 2552** which contains the database. ^If the path begins with a '/' character, 2553** then it is interpreted as an absolute path. ^If the path does not begin 2554** with a '/' (meaning that the authority section is omitted from the URI) 2555** then the path is interpreted as a relative path. 2556** ^On windows, the first component of an absolute path 2557** is a drive specification (e.g. "C:"). 2558** 2559** [[core URI query parameters]] 2560** The query component of a URI may contain parameters that are interpreted 2561** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2562** SQLite interprets the following three query parameters: 2563** 2564** <ul> 2565** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2566** a VFS object that provides the operating system interface that should 2567** be used to access the database file on disk. ^If this option is set to 2568** an empty string the default VFS object is used. ^Specifying an unknown 2569** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2570** present, then the VFS specified by the option takes precedence over 2571** the value passed as the fourth parameter to sqlite3_open_v2(). 2572** 2573** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw" or 2574** "rwc". Attempting to set it to any other value is an error)^. 2575** ^If "ro" is specified, then the database is opened for read-only 2576** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2577** third argument to sqlite3_prepare_v2(). ^If the mode option is set to 2578** "rw", then the database is opened for read-write (but not create) 2579** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2580** been set. ^Value "rwc" is equivalent to setting both 2581** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If sqlite3_open_v2() is 2582** used, it is an error to specify a value for the mode parameter that is 2583** less restrictive than that specified by the flags passed as the third 2584** parameter. 2585** 2586** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2587** "private". ^Setting it to "shared" is equivalent to setting the 2588** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2589** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2590** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2591** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2592** a URI filename, its value overrides any behaviour requested by setting 2593** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2594** </ul> 2595** 2596** ^Specifying an unknown parameter in the query component of a URI is not an 2597** error. Future versions of SQLite might understand additional query 2598** parameters. See "[query parameters with special meaning to SQLite]" for 2599** additional information. 2600** 2601** [[URI filename examples]] <h3>URI filename examples</h3> 2602** 2603** <table border="1" align=center cellpadding=5> 2604** <tr><th> URI filenames <th> Results 2605** <tr><td> file:data.db <td> 2606** Open the file "data.db" in the current directory. 2607** <tr><td> file:/home/fred/data.db<br> 2608** file:///home/fred/data.db <br> 2609** file://localhost/home/fred/data.db <br> <td> 2610** Open the database file "/home/fred/data.db". 2611** <tr><td> file://darkstar/home/fred/data.db <td> 2612** An error. "darkstar" is not a recognized authority. 2613** <tr><td style="white-space:nowrap"> 2614** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2615** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2616** C:. Note that the %20 escaping in this example is not strictly 2617** necessary - space characters can be used literally 2618** in URI filenames. 2619** <tr><td> file:data.db?mode=ro&cache=private <td> 2620** Open file "data.db" in the current directory for read-only access. 2621** Regardless of whether or not shared-cache mode is enabled by 2622** default, use a private cache. 2623** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2624** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2625** <tr><td> file:data.db?mode=readonly <td> 2626** An error. "readonly" is not a valid option for the "mode" parameter. 2627** </table> 2628** 2629** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2630** query components of a URI. A hexadecimal escape sequence consists of a 2631** percent sign - "%" - followed by exactly two hexadecimal digits 2632** specifying an octet value. ^Before the path or query components of a 2633** URI filename are interpreted, they are encoded using UTF-8 and all 2634** hexadecimal escape sequences replaced by a single byte containing the 2635** corresponding octet. If this process generates an invalid UTF-8 encoding, 2636** the results are undefined. 2637** 2638** <b>Note to Windows users:</b> The encoding used for the filename argument 2639** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2640** codepage is currently defined. Filenames containing international 2641** characters must be converted to UTF-8 prior to passing them into 2642** sqlite3_open() or sqlite3_open_v2(). 2643*/ 2644int sqlite3_open( 2645 const char *filename, /* Database filename (UTF-8) */ 2646 sqlite3 **ppDb /* OUT: SQLite db handle */ 2647); 2648int sqlite3_open16( 2649 const void *filename, /* Database filename (UTF-16) */ 2650 sqlite3 **ppDb /* OUT: SQLite db handle */ 2651); 2652int sqlite3_open_v2( 2653 const char *filename, /* Database filename (UTF-8) */ 2654 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2655 int flags, /* Flags */ 2656 const char *zVfs /* Name of VFS module to use */ 2657); 2658 2659/* 2660** CAPI3REF: Obtain Values For URI Parameters 2661** 2662** These are utility routines, useful to VFS implementations, that check 2663** to see if a database file was a URI that contained a specific query 2664** parameter, and if so obtains the value of that query parameter. 2665** 2666** If F is the database filename pointer passed into the xOpen() method of 2667** a VFS implementation when the flags parameter to xOpen() has one or 2668** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2669** P is the name of the query parameter, then 2670** sqlite3_uri_parameter(F,P) returns the value of the P 2671** parameter if it exists or a NULL pointer if P does not appear as a 2672** query parameter on F. If P is a query parameter of F 2673** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2674** a pointer to an empty string. 2675** 2676** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2677** parameter and returns true (1) or false (0) according to the value 2678** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2679** value of query parameter P is one of "yes", "true", or "on" in any 2680** case or if the value begins with a non-zero number. The 2681** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2682** query parameter P is one of "no", "false", or "off" in any case or 2683** if the value begins with a numeric zero. If P is not a query 2684** parameter on F or if the value of P is does not match any of the 2685** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2686** 2687** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2688** 64-bit signed integer and returns that integer, or D if P does not 2689** exist. If the value of P is something other than an integer, then 2690** zero is returned. 2691** 2692** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2693** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2694** is not a database file pathname pointer that SQLite passed into the xOpen 2695** VFS method, then the behavior of this routine is undefined and probably 2696** undesirable. 2697*/ 2698const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2699int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2700sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2701 2702 2703/* 2704** CAPI3REF: Error Codes And Messages 2705** 2706** ^The sqlite3_errcode() interface returns the numeric [result code] or 2707** [extended result code] for the most recent failed sqlite3_* API call 2708** associated with a [database connection]. If a prior API call failed 2709** but the most recent API call succeeded, the return value from 2710** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2711** interface is the same except that it always returns the 2712** [extended result code] even when extended result codes are 2713** disabled. 2714** 2715** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2716** text that describes the error, as either UTF-8 or UTF-16 respectively. 2717** ^(Memory to hold the error message string is managed internally. 2718** The application does not need to worry about freeing the result. 2719** However, the error string might be overwritten or deallocated by 2720** subsequent calls to other SQLite interface functions.)^ 2721** 2722** When the serialized [threading mode] is in use, it might be the 2723** case that a second error occurs on a separate thread in between 2724** the time of the first error and the call to these interfaces. 2725** When that happens, the second error will be reported since these 2726** interfaces always report the most recent result. To avoid 2727** this, each thread can obtain exclusive use of the [database connection] D 2728** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2729** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2730** all calls to the interfaces listed here are completed. 2731** 2732** If an interface fails with SQLITE_MISUSE, that means the interface 2733** was invoked incorrectly by the application. In that case, the 2734** error code and message may or may not be set. 2735*/ 2736int sqlite3_errcode(sqlite3 *db); 2737int sqlite3_extended_errcode(sqlite3 *db); 2738const char *sqlite3_errmsg(sqlite3*); 2739const void *sqlite3_errmsg16(sqlite3*); 2740 2741/* 2742** CAPI3REF: SQL Statement Object 2743** KEYWORDS: {prepared statement} {prepared statements} 2744** 2745** An instance of this object represents a single SQL statement. 2746** This object is variously known as a "prepared statement" or a 2747** "compiled SQL statement" or simply as a "statement". 2748** 2749** The life of a statement object goes something like this: 2750** 2751** <ol> 2752** <li> Create the object using [sqlite3_prepare_v2()] or a related 2753** function. 2754** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2755** interfaces. 2756** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2757** <li> Reset the statement using [sqlite3_reset()] then go back 2758** to step 2. Do this zero or more times. 2759** <li> Destroy the object using [sqlite3_finalize()]. 2760** </ol> 2761** 2762** Refer to documentation on individual methods above for additional 2763** information. 2764*/ 2765typedef struct sqlite3_stmt sqlite3_stmt; 2766 2767/* 2768** CAPI3REF: Run-time Limits 2769** 2770** ^(This interface allows the size of various constructs to be limited 2771** on a connection by connection basis. The first parameter is the 2772** [database connection] whose limit is to be set or queried. The 2773** second parameter is one of the [limit categories] that define a 2774** class of constructs to be size limited. The third parameter is the 2775** new limit for that construct.)^ 2776** 2777** ^If the new limit is a negative number, the limit is unchanged. 2778** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2779** [limits | hard upper bound] 2780** set at compile-time by a C preprocessor macro called 2781** [limits | SQLITE_MAX_<i>NAME</i>]. 2782** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2783** ^Attempts to increase a limit above its hard upper bound are 2784** silently truncated to the hard upper bound. 2785** 2786** ^Regardless of whether or not the limit was changed, the 2787** [sqlite3_limit()] interface returns the prior value of the limit. 2788** ^Hence, to find the current value of a limit without changing it, 2789** simply invoke this interface with the third parameter set to -1. 2790** 2791** Run-time limits are intended for use in applications that manage 2792** both their own internal database and also databases that are controlled 2793** by untrusted external sources. An example application might be a 2794** web browser that has its own databases for storing history and 2795** separate databases controlled by JavaScript applications downloaded 2796** off the Internet. The internal databases can be given the 2797** large, default limits. Databases managed by external sources can 2798** be given much smaller limits designed to prevent a denial of service 2799** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2800** interface to further control untrusted SQL. The size of the database 2801** created by an untrusted script can be contained using the 2802** [max_page_count] [PRAGMA]. 2803** 2804** New run-time limit categories may be added in future releases. 2805*/ 2806int sqlite3_limit(sqlite3*, int id, int newVal); 2807 2808/* 2809** CAPI3REF: Run-Time Limit Categories 2810** KEYWORDS: {limit category} {*limit categories} 2811** 2812** These constants define various performance limits 2813** that can be lowered at run-time using [sqlite3_limit()]. 2814** The synopsis of the meanings of the various limits is shown below. 2815** Additional information is available at [limits | Limits in SQLite]. 2816** 2817** <dl> 2818** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2819** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2820** 2821** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2822** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2823** 2824** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2825** <dd>The maximum number of columns in a table definition or in the 2826** result set of a [SELECT] or the maximum number of columns in an index 2827** or in an ORDER BY or GROUP BY clause.</dd>)^ 2828** 2829** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2830** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2831** 2832** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2833** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2834** 2835** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2836** <dd>The maximum number of instructions in a virtual machine program 2837** used to implement an SQL statement. This limit is not currently 2838** enforced, though that might be added in some future release of 2839** SQLite.</dd>)^ 2840** 2841** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2842** <dd>The maximum number of arguments on a function.</dd>)^ 2843** 2844** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2845** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2846** 2847** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2848** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2849** <dd>The maximum length of the pattern argument to the [LIKE] or 2850** [GLOB] operators.</dd>)^ 2851** 2852** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2853** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2854** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2855** 2856** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2857** <dd>The maximum depth of recursion for triggers.</dd>)^ 2858** </dl> 2859*/ 2860#define SQLITE_LIMIT_LENGTH 0 2861#define SQLITE_LIMIT_SQL_LENGTH 1 2862#define SQLITE_LIMIT_COLUMN 2 2863#define SQLITE_LIMIT_EXPR_DEPTH 3 2864#define SQLITE_LIMIT_COMPOUND_SELECT 4 2865#define SQLITE_LIMIT_VDBE_OP 5 2866#define SQLITE_LIMIT_FUNCTION_ARG 6 2867#define SQLITE_LIMIT_ATTACHED 7 2868#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2869#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2870#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2871 2872/* 2873** CAPI3REF: Compiling An SQL Statement 2874** KEYWORDS: {SQL statement compiler} 2875** 2876** To execute an SQL query, it must first be compiled into a byte-code 2877** program using one of these routines. 2878** 2879** The first argument, "db", is a [database connection] obtained from a 2880** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2881** [sqlite3_open16()]. The database connection must not have been closed. 2882** 2883** The second argument, "zSql", is the statement to be compiled, encoded 2884** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2885** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2886** use UTF-16. 2887** 2888** ^If the nByte argument is less than zero, then zSql is read up to the 2889** first zero terminator. ^If nByte is non-negative, then it is the maximum 2890** number of bytes read from zSql. ^When nByte is non-negative, the 2891** zSql string ends at either the first '\000' or '\u0000' character or 2892** the nByte-th byte, whichever comes first. If the caller knows 2893** that the supplied string is nul-terminated, then there is a small 2894** performance advantage to be gained by passing an nByte parameter that 2895** is equal to the number of bytes in the input string <i>including</i> 2896** the nul-terminator bytes as this saves SQLite from having to 2897** make a copy of the input string. 2898** 2899** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2900** past the end of the first SQL statement in zSql. These routines only 2901** compile the first statement in zSql, so *pzTail is left pointing to 2902** what remains uncompiled. 2903** 2904** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2905** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2906** to NULL. ^If the input text contains no SQL (if the input is an empty 2907** string or a comment) then *ppStmt is set to NULL. 2908** The calling procedure is responsible for deleting the compiled 2909** SQL statement using [sqlite3_finalize()] after it has finished with it. 2910** ppStmt may not be NULL. 2911** 2912** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2913** otherwise an [error code] is returned. 2914** 2915** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2916** recommended for all new programs. The two older interfaces are retained 2917** for backwards compatibility, but their use is discouraged. 2918** ^In the "v2" interfaces, the prepared statement 2919** that is returned (the [sqlite3_stmt] object) contains a copy of the 2920** original SQL text. This causes the [sqlite3_step()] interface to 2921** behave differently in three ways: 2922** 2923** <ol> 2924** <li> 2925** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2926** always used to do, [sqlite3_step()] will automatically recompile the SQL 2927** statement and try to run it again. 2928** </li> 2929** 2930** <li> 2931** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2932** [error codes] or [extended error codes]. ^The legacy behavior was that 2933** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2934** and the application would have to make a second call to [sqlite3_reset()] 2935** in order to find the underlying cause of the problem. With the "v2" prepare 2936** interfaces, the underlying reason for the error is returned immediately. 2937** </li> 2938** 2939** <li> 2940** ^If the specific value bound to [parameter | host parameter] in the 2941** WHERE clause might influence the choice of query plan for a statement, 2942** then the statement will be automatically recompiled, as if there had been 2943** a schema change, on the first [sqlite3_step()] call following any change 2944** to the [sqlite3_bind_text | bindings] of that [parameter]. 2945** ^The specific value of WHERE-clause [parameter] might influence the 2946** choice of query plan if the parameter is the left-hand side of a [LIKE] 2947** or [GLOB] operator or if the parameter is compared to an indexed column 2948** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 2949** the 2950** </li> 2951** </ol> 2952*/ 2953int sqlite3_prepare( 2954 sqlite3 *db, /* Database handle */ 2955 const char *zSql, /* SQL statement, UTF-8 encoded */ 2956 int nByte, /* Maximum length of zSql in bytes. */ 2957 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2958 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2959); 2960int sqlite3_prepare_v2( 2961 sqlite3 *db, /* Database handle */ 2962 const char *zSql, /* SQL statement, UTF-8 encoded */ 2963 int nByte, /* Maximum length of zSql in bytes. */ 2964 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2965 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2966); 2967int sqlite3_prepare16( 2968 sqlite3 *db, /* Database handle */ 2969 const void *zSql, /* SQL statement, UTF-16 encoded */ 2970 int nByte, /* Maximum length of zSql in bytes. */ 2971 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2972 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2973); 2974int sqlite3_prepare16_v2( 2975 sqlite3 *db, /* Database handle */ 2976 const void *zSql, /* SQL statement, UTF-16 encoded */ 2977 int nByte, /* Maximum length of zSql in bytes. */ 2978 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2979 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2980); 2981 2982/* 2983** CAPI3REF: Retrieving Statement SQL 2984** 2985** ^This interface can be used to retrieve a saved copy of the original 2986** SQL text used to create a [prepared statement] if that statement was 2987** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2988*/ 2989const char *sqlite3_sql(sqlite3_stmt *pStmt); 2990 2991/* 2992** CAPI3REF: Determine If An SQL Statement Writes The Database 2993** 2994** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 2995** and only if the [prepared statement] X makes no direct changes to 2996** the content of the database file. 2997** 2998** Note that [application-defined SQL functions] or 2999** [virtual tables] might change the database indirectly as a side effect. 3000** ^(For example, if an application defines a function "eval()" that 3001** calls [sqlite3_exec()], then the following SQL statement would 3002** change the database file through side-effects: 3003** 3004** <blockquote><pre> 3005** SELECT eval('DELETE FROM t1') FROM t2; 3006** </pre></blockquote> 3007** 3008** But because the [SELECT] statement does not change the database file 3009** directly, sqlite3_stmt_readonly() would still return true.)^ 3010** 3011** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3012** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3013** since the statements themselves do not actually modify the database but 3014** rather they control the timing of when other statements modify the 3015** database. ^The [ATTACH] and [DETACH] statements also cause 3016** sqlite3_stmt_readonly() to return true since, while those statements 3017** change the configuration of a database connection, they do not make 3018** changes to the content of the database files on disk. 3019*/ 3020int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3021 3022/* 3023** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3024** 3025** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3026** [prepared statement] S has been stepped at least once using 3027** [sqlite3_step(S)] but has not run to completion and/or has not 3028** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3029** interface returns false if S is a NULL pointer. If S is not a 3030** NULL pointer and is not a pointer to a valid [prepared statement] 3031** object, then the behavior is undefined and probably undesirable. 3032** 3033** This interface can be used in combination [sqlite3_next_stmt()] 3034** to locate all prepared statements associated with a database 3035** connection that are in need of being reset. This can be used, 3036** for example, in diagnostic routines to search for prepared 3037** statements that are holding a transaction open. 3038*/ 3039int sqlite3_stmt_busy(sqlite3_stmt*); 3040 3041/* 3042** CAPI3REF: Dynamically Typed Value Object 3043** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3044** 3045** SQLite uses the sqlite3_value object to represent all values 3046** that can be stored in a database table. SQLite uses dynamic typing 3047** for the values it stores. ^Values stored in sqlite3_value objects 3048** can be integers, floating point values, strings, BLOBs, or NULL. 3049** 3050** An sqlite3_value object may be either "protected" or "unprotected". 3051** Some interfaces require a protected sqlite3_value. Other interfaces 3052** will accept either a protected or an unprotected sqlite3_value. 3053** Every interface that accepts sqlite3_value arguments specifies 3054** whether or not it requires a protected sqlite3_value. 3055** 3056** The terms "protected" and "unprotected" refer to whether or not 3057** a mutex is held. An internal mutex is held for a protected 3058** sqlite3_value object but no mutex is held for an unprotected 3059** sqlite3_value object. If SQLite is compiled to be single-threaded 3060** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3061** or if SQLite is run in one of reduced mutex modes 3062** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3063** then there is no distinction between protected and unprotected 3064** sqlite3_value objects and they can be used interchangeably. However, 3065** for maximum code portability it is recommended that applications 3066** still make the distinction between protected and unprotected 3067** sqlite3_value objects even when not strictly required. 3068** 3069** ^The sqlite3_value objects that are passed as parameters into the 3070** implementation of [application-defined SQL functions] are protected. 3071** ^The sqlite3_value object returned by 3072** [sqlite3_column_value()] is unprotected. 3073** Unprotected sqlite3_value objects may only be used with 3074** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3075** The [sqlite3_value_blob | sqlite3_value_type()] family of 3076** interfaces require protected sqlite3_value objects. 3077*/ 3078typedef struct Mem sqlite3_value; 3079 3080/* 3081** CAPI3REF: SQL Function Context Object 3082** 3083** The context in which an SQL function executes is stored in an 3084** sqlite3_context object. ^A pointer to an sqlite3_context object 3085** is always first parameter to [application-defined SQL functions]. 3086** The application-defined SQL function implementation will pass this 3087** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3088** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3089** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3090** and/or [sqlite3_set_auxdata()]. 3091*/ 3092typedef struct sqlite3_context sqlite3_context; 3093 3094/* 3095** CAPI3REF: Binding Values To Prepared Statements 3096** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3097** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3098** 3099** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3100** literals may be replaced by a [parameter] that matches one of following 3101** templates: 3102** 3103** <ul> 3104** <li> ? 3105** <li> ?NNN 3106** <li> :VVV 3107** <li> @VVV 3108** <li> $VVV 3109** </ul> 3110** 3111** In the templates above, NNN represents an integer literal, 3112** and VVV represents an alphanumeric identifier.)^ ^The values of these 3113** parameters (also called "host parameter names" or "SQL parameters") 3114** can be set using the sqlite3_bind_*() routines defined here. 3115** 3116** ^The first argument to the sqlite3_bind_*() routines is always 3117** a pointer to the [sqlite3_stmt] object returned from 3118** [sqlite3_prepare_v2()] or its variants. 3119** 3120** ^The second argument is the index of the SQL parameter to be set. 3121** ^The leftmost SQL parameter has an index of 1. ^When the same named 3122** SQL parameter is used more than once, second and subsequent 3123** occurrences have the same index as the first occurrence. 3124** ^The index for named parameters can be looked up using the 3125** [sqlite3_bind_parameter_index()] API if desired. ^The index 3126** for "?NNN" parameters is the value of NNN. 3127** ^The NNN value must be between 1 and the [sqlite3_limit()] 3128** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3129** 3130** ^The third argument is the value to bind to the parameter. 3131** 3132** ^(In those routines that have a fourth argument, its value is the 3133** number of bytes in the parameter. To be clear: the value is the 3134** number of <u>bytes</u> in the value, not the number of characters.)^ 3135** ^If the fourth parameter is negative, the length of the string is 3136** the number of bytes up to the first zero terminator. 3137** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3138** or sqlite3_bind_text16() then that parameter must be the byte offset 3139** where the NUL terminator would occur assuming the string were NUL 3140** terminated. If any NUL characters occur at byte offsets less than 3141** the value of the fourth parameter then the resulting string value will 3142** contain embedded NULs. The result of expressions involving strings 3143** with embedded NULs is undefined. 3144** 3145** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3146** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3147** string after SQLite has finished with it. ^The destructor is called 3148** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3149** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3150** ^If the fifth argument is 3151** the special value [SQLITE_STATIC], then SQLite assumes that the 3152** information is in static, unmanaged space and does not need to be freed. 3153** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3154** SQLite makes its own private copy of the data immediately, before 3155** the sqlite3_bind_*() routine returns. 3156** 3157** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3158** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3159** (just an integer to hold its size) while it is being processed. 3160** Zeroblobs are intended to serve as placeholders for BLOBs whose 3161** content is later written using 3162** [sqlite3_blob_open | incremental BLOB I/O] routines. 3163** ^A negative value for the zeroblob results in a zero-length BLOB. 3164** 3165** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3166** for the [prepared statement] or with a prepared statement for which 3167** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3168** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3169** routine is passed a [prepared statement] that has been finalized, the 3170** result is undefined and probably harmful. 3171** 3172** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3173** ^Unbound parameters are interpreted as NULL. 3174** 3175** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3176** [error code] if anything goes wrong. 3177** ^[SQLITE_RANGE] is returned if the parameter 3178** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3179** 3180** See also: [sqlite3_bind_parameter_count()], 3181** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3182*/ 3183int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3184int sqlite3_bind_double(sqlite3_stmt*, int, double); 3185int sqlite3_bind_int(sqlite3_stmt*, int, int); 3186int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3187int sqlite3_bind_null(sqlite3_stmt*, int); 3188int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3189int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3190int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3191int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3192 3193/* 3194** CAPI3REF: Number Of SQL Parameters 3195** 3196** ^This routine can be used to find the number of [SQL parameters] 3197** in a [prepared statement]. SQL parameters are tokens of the 3198** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3199** placeholders for values that are [sqlite3_bind_blob | bound] 3200** to the parameters at a later time. 3201** 3202** ^(This routine actually returns the index of the largest (rightmost) 3203** parameter. For all forms except ?NNN, this will correspond to the 3204** number of unique parameters. If parameters of the ?NNN form are used, 3205** there may be gaps in the list.)^ 3206** 3207** See also: [sqlite3_bind_blob|sqlite3_bind()], 3208** [sqlite3_bind_parameter_name()], and 3209** [sqlite3_bind_parameter_index()]. 3210*/ 3211int sqlite3_bind_parameter_count(sqlite3_stmt*); 3212 3213/* 3214** CAPI3REF: Name Of A Host Parameter 3215** 3216** ^The sqlite3_bind_parameter_name(P,N) interface returns 3217** the name of the N-th [SQL parameter] in the [prepared statement] P. 3218** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3219** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3220** respectively. 3221** In other words, the initial ":" or "$" or "@" or "?" 3222** is included as part of the name.)^ 3223** ^Parameters of the form "?" without a following integer have no name 3224** and are referred to as "nameless" or "anonymous parameters". 3225** 3226** ^The first host parameter has an index of 1, not 0. 3227** 3228** ^If the value N is out of range or if the N-th parameter is 3229** nameless, then NULL is returned. ^The returned string is 3230** always in UTF-8 encoding even if the named parameter was 3231** originally specified as UTF-16 in [sqlite3_prepare16()] or 3232** [sqlite3_prepare16_v2()]. 3233** 3234** See also: [sqlite3_bind_blob|sqlite3_bind()], 3235** [sqlite3_bind_parameter_count()], and 3236** [sqlite3_bind_parameter_index()]. 3237*/ 3238const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3239 3240/* 3241** CAPI3REF: Index Of A Parameter With A Given Name 3242** 3243** ^Return the index of an SQL parameter given its name. ^The 3244** index value returned is suitable for use as the second 3245** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3246** is returned if no matching parameter is found. ^The parameter 3247** name must be given in UTF-8 even if the original statement 3248** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3249** 3250** See also: [sqlite3_bind_blob|sqlite3_bind()], 3251** [sqlite3_bind_parameter_count()], and 3252** [sqlite3_bind_parameter_index()]. 3253*/ 3254int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3255 3256/* 3257** CAPI3REF: Reset All Bindings On A Prepared Statement 3258** 3259** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3260** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3261** ^Use this routine to reset all host parameters to NULL. 3262*/ 3263int sqlite3_clear_bindings(sqlite3_stmt*); 3264 3265/* 3266** CAPI3REF: Number Of Columns In A Result Set 3267** 3268** ^Return the number of columns in the result set returned by the 3269** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3270** statement that does not return data (for example an [UPDATE]). 3271** 3272** See also: [sqlite3_data_count()] 3273*/ 3274int sqlite3_column_count(sqlite3_stmt *pStmt); 3275 3276/* 3277** CAPI3REF: Column Names In A Result Set 3278** 3279** ^These routines return the name assigned to a particular column 3280** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3281** interface returns a pointer to a zero-terminated UTF-8 string 3282** and sqlite3_column_name16() returns a pointer to a zero-terminated 3283** UTF-16 string. ^The first parameter is the [prepared statement] 3284** that implements the [SELECT] statement. ^The second parameter is the 3285** column number. ^The leftmost column is number 0. 3286** 3287** ^The returned string pointer is valid until either the [prepared statement] 3288** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3289** reprepared by the first call to [sqlite3_step()] for a particular run 3290** or until the next call to 3291** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3292** 3293** ^If sqlite3_malloc() fails during the processing of either routine 3294** (for example during a conversion from UTF-8 to UTF-16) then a 3295** NULL pointer is returned. 3296** 3297** ^The name of a result column is the value of the "AS" clause for 3298** that column, if there is an AS clause. If there is no AS clause 3299** then the name of the column is unspecified and may change from 3300** one release of SQLite to the next. 3301*/ 3302const char *sqlite3_column_name(sqlite3_stmt*, int N); 3303const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3304 3305/* 3306** CAPI3REF: Source Of Data In A Query Result 3307** 3308** ^These routines provide a means to determine the database, table, and 3309** table column that is the origin of a particular result column in 3310** [SELECT] statement. 3311** ^The name of the database or table or column can be returned as 3312** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3313** the database name, the _table_ routines return the table name, and 3314** the origin_ routines return the column name. 3315** ^The returned string is valid until the [prepared statement] is destroyed 3316** using [sqlite3_finalize()] or until the statement is automatically 3317** reprepared by the first call to [sqlite3_step()] for a particular run 3318** or until the same information is requested 3319** again in a different encoding. 3320** 3321** ^The names returned are the original un-aliased names of the 3322** database, table, and column. 3323** 3324** ^The first argument to these interfaces is a [prepared statement]. 3325** ^These functions return information about the Nth result column returned by 3326** the statement, where N is the second function argument. 3327** ^The left-most column is column 0 for these routines. 3328** 3329** ^If the Nth column returned by the statement is an expression or 3330** subquery and is not a column value, then all of these functions return 3331** NULL. ^These routine might also return NULL if a memory allocation error 3332** occurs. ^Otherwise, they return the name of the attached database, table, 3333** or column that query result column was extracted from. 3334** 3335** ^As with all other SQLite APIs, those whose names end with "16" return 3336** UTF-16 encoded strings and the other functions return UTF-8. 3337** 3338** ^These APIs are only available if the library was compiled with the 3339** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3340** 3341** If two or more threads call one or more of these routines against the same 3342** prepared statement and column at the same time then the results are 3343** undefined. 3344** 3345** If two or more threads call one or more 3346** [sqlite3_column_database_name | column metadata interfaces] 3347** for the same [prepared statement] and result column 3348** at the same time then the results are undefined. 3349*/ 3350const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3351const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3352const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3353const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3354const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3355const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3356 3357/* 3358** CAPI3REF: Declared Datatype Of A Query Result 3359** 3360** ^(The first parameter is a [prepared statement]. 3361** If this statement is a [SELECT] statement and the Nth column of the 3362** returned result set of that [SELECT] is a table column (not an 3363** expression or subquery) then the declared type of the table 3364** column is returned.)^ ^If the Nth column of the result set is an 3365** expression or subquery, then a NULL pointer is returned. 3366** ^The returned string is always UTF-8 encoded. 3367** 3368** ^(For example, given the database schema: 3369** 3370** CREATE TABLE t1(c1 VARIANT); 3371** 3372** and the following statement to be compiled: 3373** 3374** SELECT c1 + 1, c1 FROM t1; 3375** 3376** this routine would return the string "VARIANT" for the second result 3377** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3378** 3379** ^SQLite uses dynamic run-time typing. ^So just because a column 3380** is declared to contain a particular type does not mean that the 3381** data stored in that column is of the declared type. SQLite is 3382** strongly typed, but the typing is dynamic not static. ^Type 3383** is associated with individual values, not with the containers 3384** used to hold those values. 3385*/ 3386const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3387const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3388 3389/* 3390** CAPI3REF: Evaluate An SQL Statement 3391** 3392** After a [prepared statement] has been prepared using either 3393** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3394** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3395** must be called one or more times to evaluate the statement. 3396** 3397** The details of the behavior of the sqlite3_step() interface depend 3398** on whether the statement was prepared using the newer "v2" interface 3399** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3400** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3401** new "v2" interface is recommended for new applications but the legacy 3402** interface will continue to be supported. 3403** 3404** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3405** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3406** ^With the "v2" interface, any of the other [result codes] or 3407** [extended result codes] might be returned as well. 3408** 3409** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3410** database locks it needs to do its job. ^If the statement is a [COMMIT] 3411** or occurs outside of an explicit transaction, then you can retry the 3412** statement. If the statement is not a [COMMIT] and occurs within an 3413** explicit transaction then you should rollback the transaction before 3414** continuing. 3415** 3416** ^[SQLITE_DONE] means that the statement has finished executing 3417** successfully. sqlite3_step() should not be called again on this virtual 3418** machine without first calling [sqlite3_reset()] to reset the virtual 3419** machine back to its initial state. 3420** 3421** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3422** is returned each time a new row of data is ready for processing by the 3423** caller. The values may be accessed using the [column access functions]. 3424** sqlite3_step() is called again to retrieve the next row of data. 3425** 3426** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3427** violation) has occurred. sqlite3_step() should not be called again on 3428** the VM. More information may be found by calling [sqlite3_errmsg()]. 3429** ^With the legacy interface, a more specific error code (for example, 3430** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3431** can be obtained by calling [sqlite3_reset()] on the 3432** [prepared statement]. ^In the "v2" interface, 3433** the more specific error code is returned directly by sqlite3_step(). 3434** 3435** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3436** Perhaps it was called on a [prepared statement] that has 3437** already been [sqlite3_finalize | finalized] or on one that had 3438** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3439** be the case that the same database connection is being used by two or 3440** more threads at the same moment in time. 3441** 3442** For all versions of SQLite up to and including 3.6.23.1, a call to 3443** [sqlite3_reset()] was required after sqlite3_step() returned anything 3444** other than [SQLITE_ROW] before any subsequent invocation of 3445** sqlite3_step(). Failure to reset the prepared statement using 3446** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3447** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3448** calling [sqlite3_reset()] automatically in this circumstance rather 3449** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3450** break because any application that ever receives an SQLITE_MISUSE error 3451** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3452** can be used to restore the legacy behavior. 3453** 3454** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3455** API always returns a generic error code, [SQLITE_ERROR], following any 3456** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3457** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3458** specific [error codes] that better describes the error. 3459** We admit that this is a goofy design. The problem has been fixed 3460** with the "v2" interface. If you prepare all of your SQL statements 3461** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3462** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3463** then the more specific [error codes] are returned directly 3464** by sqlite3_step(). The use of the "v2" interface is recommended. 3465*/ 3466int sqlite3_step(sqlite3_stmt*); 3467 3468/* 3469** CAPI3REF: Number of columns in a result set 3470** 3471** ^The sqlite3_data_count(P) interface returns the number of columns in the 3472** current row of the result set of [prepared statement] P. 3473** ^If prepared statement P does not have results ready to return 3474** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3475** interfaces) then sqlite3_data_count(P) returns 0. 3476** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3477** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3478** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3479** will return non-zero if previous call to [sqlite3_step](P) returned 3480** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3481** where it always returns zero since each step of that multi-step 3482** pragma returns 0 columns of data. 3483** 3484** See also: [sqlite3_column_count()] 3485*/ 3486int sqlite3_data_count(sqlite3_stmt *pStmt); 3487 3488/* 3489** CAPI3REF: Fundamental Datatypes 3490** KEYWORDS: SQLITE_TEXT 3491** 3492** ^(Every value in SQLite has one of five fundamental datatypes: 3493** 3494** <ul> 3495** <li> 64-bit signed integer 3496** <li> 64-bit IEEE floating point number 3497** <li> string 3498** <li> BLOB 3499** <li> NULL 3500** </ul>)^ 3501** 3502** These constants are codes for each of those types. 3503** 3504** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3505** for a completely different meaning. Software that links against both 3506** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3507** SQLITE_TEXT. 3508*/ 3509#define SQLITE_INTEGER 1 3510#define SQLITE_FLOAT 2 3511#define SQLITE_BLOB 4 3512#define SQLITE_NULL 5 3513#ifdef SQLITE_TEXT 3514# undef SQLITE_TEXT 3515#else 3516# define SQLITE_TEXT 3 3517#endif 3518#define SQLITE3_TEXT 3 3519 3520/* 3521** CAPI3REF: Result Values From A Query 3522** KEYWORDS: {column access functions} 3523** 3524** These routines form the "result set" interface. 3525** 3526** ^These routines return information about a single column of the current 3527** result row of a query. ^In every case the first argument is a pointer 3528** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3529** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3530** and the second argument is the index of the column for which information 3531** should be returned. ^The leftmost column of the result set has the index 0. 3532** ^The number of columns in the result can be determined using 3533** [sqlite3_column_count()]. 3534** 3535** If the SQL statement does not currently point to a valid row, or if the 3536** column index is out of range, the result is undefined. 3537** These routines may only be called when the most recent call to 3538** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3539** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3540** If any of these routines are called after [sqlite3_reset()] or 3541** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3542** something other than [SQLITE_ROW], the results are undefined. 3543** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3544** are called from a different thread while any of these routines 3545** are pending, then the results are undefined. 3546** 3547** ^The sqlite3_column_type() routine returns the 3548** [SQLITE_INTEGER | datatype code] for the initial data type 3549** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3550** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3551** returned by sqlite3_column_type() is only meaningful if no type 3552** conversions have occurred as described below. After a type conversion, 3553** the value returned by sqlite3_column_type() is undefined. Future 3554** versions of SQLite may change the behavior of sqlite3_column_type() 3555** following a type conversion. 3556** 3557** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3558** routine returns the number of bytes in that BLOB or string. 3559** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3560** the string to UTF-8 and then returns the number of bytes. 3561** ^If the result is a numeric value then sqlite3_column_bytes() uses 3562** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3563** the number of bytes in that string. 3564** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3565** 3566** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3567** routine returns the number of bytes in that BLOB or string. 3568** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3569** the string to UTF-16 and then returns the number of bytes. 3570** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3571** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3572** the number of bytes in that string. 3573** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3574** 3575** ^The values returned by [sqlite3_column_bytes()] and 3576** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3577** of the string. ^For clarity: the values returned by 3578** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3579** bytes in the string, not the number of characters. 3580** 3581** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3582** even empty strings, are always zero-terminated. ^The return 3583** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3584** 3585** ^The object returned by [sqlite3_column_value()] is an 3586** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3587** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3588** If the [unprotected sqlite3_value] object returned by 3589** [sqlite3_column_value()] is used in any other way, including calls 3590** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3591** or [sqlite3_value_bytes()], then the behavior is undefined. 3592** 3593** These routines attempt to convert the value where appropriate. ^For 3594** example, if the internal representation is FLOAT and a text result 3595** is requested, [sqlite3_snprintf()] is used internally to perform the 3596** conversion automatically. ^(The following table details the conversions 3597** that are applied: 3598** 3599** <blockquote> 3600** <table border="1"> 3601** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3602** 3603** <tr><td> NULL <td> INTEGER <td> Result is 0 3604** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3605** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3606** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3607** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3608** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3609** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3610** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3611** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3612** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3613** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3614** <tr><td> TEXT <td> FLOAT <td> Use atof() 3615** <tr><td> TEXT <td> BLOB <td> No change 3616** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3617** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3618** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3619** </table> 3620** </blockquote>)^ 3621** 3622** The table above makes reference to standard C library functions atoi() 3623** and atof(). SQLite does not really use these functions. It has its 3624** own equivalent internal routines. The atoi() and atof() names are 3625** used in the table for brevity and because they are familiar to most 3626** C programmers. 3627** 3628** Note that when type conversions occur, pointers returned by prior 3629** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3630** sqlite3_column_text16() may be invalidated. 3631** Type conversions and pointer invalidations might occur 3632** in the following cases: 3633** 3634** <ul> 3635** <li> The initial content is a BLOB and sqlite3_column_text() or 3636** sqlite3_column_text16() is called. A zero-terminator might 3637** need to be added to the string.</li> 3638** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3639** sqlite3_column_text16() is called. The content must be converted 3640** to UTF-16.</li> 3641** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3642** sqlite3_column_text() is called. The content must be converted 3643** to UTF-8.</li> 3644** </ul> 3645** 3646** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3647** not invalidate a prior pointer, though of course the content of the buffer 3648** that the prior pointer references will have been modified. Other kinds 3649** of conversion are done in place when it is possible, but sometimes they 3650** are not possible and in those cases prior pointers are invalidated. 3651** 3652** The safest and easiest to remember policy is to invoke these routines 3653** in one of the following ways: 3654** 3655** <ul> 3656** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3657** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3658** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3659** </ul> 3660** 3661** In other words, you should call sqlite3_column_text(), 3662** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3663** into the desired format, then invoke sqlite3_column_bytes() or 3664** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3665** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3666** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3667** with calls to sqlite3_column_bytes(). 3668** 3669** ^The pointers returned are valid until a type conversion occurs as 3670** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3671** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3672** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3673** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3674** [sqlite3_free()]. 3675** 3676** ^(If a memory allocation error occurs during the evaluation of any 3677** of these routines, a default value is returned. The default value 3678** is either the integer 0, the floating point number 0.0, or a NULL 3679** pointer. Subsequent calls to [sqlite3_errcode()] will return 3680** [SQLITE_NOMEM].)^ 3681*/ 3682const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3683int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3684int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3685double sqlite3_column_double(sqlite3_stmt*, int iCol); 3686int sqlite3_column_int(sqlite3_stmt*, int iCol); 3687sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3688const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3689const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3690int sqlite3_column_type(sqlite3_stmt*, int iCol); 3691sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3692 3693/* 3694** CAPI3REF: Destroy A Prepared Statement Object 3695** 3696** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3697** ^If the most recent evaluation of the statement encountered no errors 3698** or if the statement is never been evaluated, then sqlite3_finalize() returns 3699** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3700** sqlite3_finalize(S) returns the appropriate [error code] or 3701** [extended error code]. 3702** 3703** ^The sqlite3_finalize(S) routine can be called at any point during 3704** the life cycle of [prepared statement] S: 3705** before statement S is ever evaluated, after 3706** one or more calls to [sqlite3_reset()], or after any call 3707** to [sqlite3_step()] regardless of whether or not the statement has 3708** completed execution. 3709** 3710** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3711** 3712** The application must finalize every [prepared statement] in order to avoid 3713** resource leaks. It is a grievous error for the application to try to use 3714** a prepared statement after it has been finalized. Any use of a prepared 3715** statement after it has been finalized can result in undefined and 3716** undesirable behavior such as segfaults and heap corruption. 3717*/ 3718int sqlite3_finalize(sqlite3_stmt *pStmt); 3719 3720/* 3721** CAPI3REF: Reset A Prepared Statement Object 3722** 3723** The sqlite3_reset() function is called to reset a [prepared statement] 3724** object back to its initial state, ready to be re-executed. 3725** ^Any SQL statement variables that had values bound to them using 3726** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3727** Use [sqlite3_clear_bindings()] to reset the bindings. 3728** 3729** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3730** back to the beginning of its program. 3731** 3732** ^If the most recent call to [sqlite3_step(S)] for the 3733** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3734** or if [sqlite3_step(S)] has never before been called on S, 3735** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3736** 3737** ^If the most recent call to [sqlite3_step(S)] for the 3738** [prepared statement] S indicated an error, then 3739** [sqlite3_reset(S)] returns an appropriate [error code]. 3740** 3741** ^The [sqlite3_reset(S)] interface does not change the values 3742** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3743*/ 3744int sqlite3_reset(sqlite3_stmt *pStmt); 3745 3746/* 3747** CAPI3REF: Create Or Redefine SQL Functions 3748** KEYWORDS: {function creation routines} 3749** KEYWORDS: {application-defined SQL function} 3750** KEYWORDS: {application-defined SQL functions} 3751** 3752** ^These functions (collectively known as "function creation routines") 3753** are used to add SQL functions or aggregates or to redefine the behavior 3754** of existing SQL functions or aggregates. The only differences between 3755** these routines are the text encoding expected for 3756** the second parameter (the name of the function being created) 3757** and the presence or absence of a destructor callback for 3758** the application data pointer. 3759** 3760** ^The first parameter is the [database connection] to which the SQL 3761** function is to be added. ^If an application uses more than one database 3762** connection then application-defined SQL functions must be added 3763** to each database connection separately. 3764** 3765** ^The second parameter is the name of the SQL function to be created or 3766** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3767** representation, exclusive of the zero-terminator. ^Note that the name 3768** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3769** ^Any attempt to create a function with a longer name 3770** will result in [SQLITE_MISUSE] being returned. 3771** 3772** ^The third parameter (nArg) 3773** is the number of arguments that the SQL function or 3774** aggregate takes. ^If this parameter is -1, then the SQL function or 3775** aggregate may take any number of arguments between 0 and the limit 3776** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3777** parameter is less than -1 or greater than 127 then the behavior is 3778** undefined. 3779** 3780** ^The fourth parameter, eTextRep, specifies what 3781** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3782** its parameters. Every SQL function implementation must be able to work 3783** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3784** more efficient with one encoding than another. ^An application may 3785** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3786** times with the same function but with different values of eTextRep. 3787** ^When multiple implementations of the same function are available, SQLite 3788** will pick the one that involves the least amount of data conversion. 3789** If there is only a single implementation which does not care what text 3790** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3791** 3792** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3793** function can gain access to this pointer using [sqlite3_user_data()].)^ 3794** 3795** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3796** pointers to C-language functions that implement the SQL function or 3797** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3798** callback only; NULL pointers must be passed as the xStep and xFinal 3799** parameters. ^An aggregate SQL function requires an implementation of xStep 3800** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3801** SQL function or aggregate, pass NULL pointers for all three function 3802** callbacks. 3803** 3804** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3805** then it is destructor for the application data pointer. 3806** The destructor is invoked when the function is deleted, either by being 3807** overloaded or when the database connection closes.)^ 3808** ^The destructor is also invoked if the call to 3809** sqlite3_create_function_v2() fails. 3810** ^When the destructor callback of the tenth parameter is invoked, it 3811** is passed a single argument which is a copy of the application data 3812** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3813** 3814** ^It is permitted to register multiple implementations of the same 3815** functions with the same name but with either differing numbers of 3816** arguments or differing preferred text encodings. ^SQLite will use 3817** the implementation that most closely matches the way in which the 3818** SQL function is used. ^A function implementation with a non-negative 3819** nArg parameter is a better match than a function implementation with 3820** a negative nArg. ^A function where the preferred text encoding 3821** matches the database encoding is a better 3822** match than a function where the encoding is different. 3823** ^A function where the encoding difference is between UTF16le and UTF16be 3824** is a closer match than a function where the encoding difference is 3825** between UTF8 and UTF16. 3826** 3827** ^Built-in functions may be overloaded by new application-defined functions. 3828** 3829** ^An application-defined function is permitted to call other 3830** SQLite interfaces. However, such calls must not 3831** close the database connection nor finalize or reset the prepared 3832** statement in which the function is running. 3833*/ 3834int sqlite3_create_function( 3835 sqlite3 *db, 3836 const char *zFunctionName, 3837 int nArg, 3838 int eTextRep, 3839 void *pApp, 3840 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3841 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3842 void (*xFinal)(sqlite3_context*) 3843); 3844int sqlite3_create_function16( 3845 sqlite3 *db, 3846 const void *zFunctionName, 3847 int nArg, 3848 int eTextRep, 3849 void *pApp, 3850 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3851 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3852 void (*xFinal)(sqlite3_context*) 3853); 3854int sqlite3_create_function_v2( 3855 sqlite3 *db, 3856 const char *zFunctionName, 3857 int nArg, 3858 int eTextRep, 3859 void *pApp, 3860 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3861 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3862 void (*xFinal)(sqlite3_context*), 3863 void(*xDestroy)(void*) 3864); 3865 3866/* 3867** CAPI3REF: Text Encodings 3868** 3869** These constant define integer codes that represent the various 3870** text encodings supported by SQLite. 3871*/ 3872#define SQLITE_UTF8 1 3873#define SQLITE_UTF16LE 2 3874#define SQLITE_UTF16BE 3 3875#define SQLITE_UTF16 4 /* Use native byte order */ 3876#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3877#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3878 3879/* 3880** CAPI3REF: Deprecated Functions 3881** DEPRECATED 3882** 3883** These functions are [deprecated]. In order to maintain 3884** backwards compatibility with older code, these functions continue 3885** to be supported. However, new applications should avoid 3886** the use of these functions. To help encourage people to avoid 3887** using these functions, we are not going to tell you what they do. 3888*/ 3889#ifndef SQLITE_OMIT_DEPRECATED 3890SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3891SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3892SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3893SQLITE_DEPRECATED int sqlite3_global_recover(void); 3894SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3895SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3896#endif 3897 3898/* 3899** CAPI3REF: Obtaining SQL Function Parameter Values 3900** 3901** The C-language implementation of SQL functions and aggregates uses 3902** this set of interface routines to access the parameter values on 3903** the function or aggregate. 3904** 3905** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3906** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3907** define callbacks that implement the SQL functions and aggregates. 3908** The 3rd parameter to these callbacks is an array of pointers to 3909** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3910** each parameter to the SQL function. These routines are used to 3911** extract values from the [sqlite3_value] objects. 3912** 3913** These routines work only with [protected sqlite3_value] objects. 3914** Any attempt to use these routines on an [unprotected sqlite3_value] 3915** object results in undefined behavior. 3916** 3917** ^These routines work just like the corresponding [column access functions] 3918** except that these routines take a single [protected sqlite3_value] object 3919** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3920** 3921** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3922** in the native byte-order of the host machine. ^The 3923** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3924** extract UTF-16 strings as big-endian and little-endian respectively. 3925** 3926** ^(The sqlite3_value_numeric_type() interface attempts to apply 3927** numeric affinity to the value. This means that an attempt is 3928** made to convert the value to an integer or floating point. If 3929** such a conversion is possible without loss of information (in other 3930** words, if the value is a string that looks like a number) 3931** then the conversion is performed. Otherwise no conversion occurs. 3932** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3933** 3934** Please pay particular attention to the fact that the pointer returned 3935** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3936** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3937** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3938** or [sqlite3_value_text16()]. 3939** 3940** These routines must be called from the same thread as 3941** the SQL function that supplied the [sqlite3_value*] parameters. 3942*/ 3943const void *sqlite3_value_blob(sqlite3_value*); 3944int sqlite3_value_bytes(sqlite3_value*); 3945int sqlite3_value_bytes16(sqlite3_value*); 3946double sqlite3_value_double(sqlite3_value*); 3947int sqlite3_value_int(sqlite3_value*); 3948sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3949const unsigned char *sqlite3_value_text(sqlite3_value*); 3950const void *sqlite3_value_text16(sqlite3_value*); 3951const void *sqlite3_value_text16le(sqlite3_value*); 3952const void *sqlite3_value_text16be(sqlite3_value*); 3953int sqlite3_value_type(sqlite3_value*); 3954int sqlite3_value_numeric_type(sqlite3_value*); 3955 3956/* 3957** CAPI3REF: Obtain Aggregate Function Context 3958** 3959** Implementations of aggregate SQL functions use this 3960** routine to allocate memory for storing their state. 3961** 3962** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3963** for a particular aggregate function, SQLite 3964** allocates N of memory, zeroes out that memory, and returns a pointer 3965** to the new memory. ^On second and subsequent calls to 3966** sqlite3_aggregate_context() for the same aggregate function instance, 3967** the same buffer is returned. Sqlite3_aggregate_context() is normally 3968** called once for each invocation of the xStep callback and then one 3969** last time when the xFinal callback is invoked. ^(When no rows match 3970** an aggregate query, the xStep() callback of the aggregate function 3971** implementation is never called and xFinal() is called exactly once. 3972** In those cases, sqlite3_aggregate_context() might be called for the 3973** first time from within xFinal().)^ 3974** 3975** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3976** less than or equal to zero or if a memory allocate error occurs. 3977** 3978** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3979** determined by the N parameter on first successful call. Changing the 3980** value of N in subsequent call to sqlite3_aggregate_context() within 3981** the same aggregate function instance will not resize the memory 3982** allocation.)^ 3983** 3984** ^SQLite automatically frees the memory allocated by 3985** sqlite3_aggregate_context() when the aggregate query concludes. 3986** 3987** The first parameter must be a copy of the 3988** [sqlite3_context | SQL function context] that is the first parameter 3989** to the xStep or xFinal callback routine that implements the aggregate 3990** function. 3991** 3992** This routine must be called from the same thread in which 3993** the aggregate SQL function is running. 3994*/ 3995void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3996 3997/* 3998** CAPI3REF: User Data For Functions 3999** 4000** ^The sqlite3_user_data() interface returns a copy of 4001** the pointer that was the pUserData parameter (the 5th parameter) 4002** of the [sqlite3_create_function()] 4003** and [sqlite3_create_function16()] routines that originally 4004** registered the application defined function. 4005** 4006** This routine must be called from the same thread in which 4007** the application-defined function is running. 4008*/ 4009void *sqlite3_user_data(sqlite3_context*); 4010 4011/* 4012** CAPI3REF: Database Connection For Functions 4013** 4014** ^The sqlite3_context_db_handle() interface returns a copy of 4015** the pointer to the [database connection] (the 1st parameter) 4016** of the [sqlite3_create_function()] 4017** and [sqlite3_create_function16()] routines that originally 4018** registered the application defined function. 4019*/ 4020sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4021 4022/* 4023** CAPI3REF: Function Auxiliary Data 4024** 4025** The following two functions may be used by scalar SQL functions to 4026** associate metadata with argument values. If the same value is passed to 4027** multiple invocations of the same SQL function during query execution, under 4028** some circumstances the associated metadata may be preserved. This may 4029** be used, for example, to add a regular-expression matching scalar 4030** function. The compiled version of the regular expression is stored as 4031** metadata associated with the SQL value passed as the regular expression 4032** pattern. The compiled regular expression can be reused on multiple 4033** invocations of the same function so that the original pattern string 4034** does not need to be recompiled on each invocation. 4035** 4036** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4037** associated by the sqlite3_set_auxdata() function with the Nth argument 4038** value to the application-defined function. ^If no metadata has been ever 4039** been set for the Nth argument of the function, or if the corresponding 4040** function parameter has changed since the meta-data was set, 4041** then sqlite3_get_auxdata() returns a NULL pointer. 4042** 4043** ^The sqlite3_set_auxdata() interface saves the metadata 4044** pointed to by its 3rd parameter as the metadata for the N-th 4045** argument of the application-defined function. Subsequent 4046** calls to sqlite3_get_auxdata() might return this data, if it has 4047** not been destroyed. 4048** ^If it is not NULL, SQLite will invoke the destructor 4049** function given by the 4th parameter to sqlite3_set_auxdata() on 4050** the metadata when the corresponding function parameter changes 4051** or when the SQL statement completes, whichever comes first. 4052** 4053** SQLite is free to call the destructor and drop metadata on any 4054** parameter of any function at any time. ^The only guarantee is that 4055** the destructor will be called before the metadata is dropped. 4056** 4057** ^(In practice, metadata is preserved between function calls for 4058** expressions that are constant at compile time. This includes literal 4059** values and [parameters].)^ 4060** 4061** These routines must be called from the same thread in which 4062** the SQL function is running. 4063*/ 4064void *sqlite3_get_auxdata(sqlite3_context*, int N); 4065void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4066 4067 4068/* 4069** CAPI3REF: Constants Defining Special Destructor Behavior 4070** 4071** These are special values for the destructor that is passed in as the 4072** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4073** argument is SQLITE_STATIC, it means that the content pointer is constant 4074** and will never change. It does not need to be destroyed. ^The 4075** SQLITE_TRANSIENT value means that the content will likely change in 4076** the near future and that SQLite should make its own private copy of 4077** the content before returning. 4078** 4079** The typedef is necessary to work around problems in certain 4080** C++ compilers. See ticket #2191. 4081*/ 4082typedef void (*sqlite3_destructor_type)(void*); 4083#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4084#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4085 4086/* 4087** CAPI3REF: Setting The Result Of An SQL Function 4088** 4089** These routines are used by the xFunc or xFinal callbacks that 4090** implement SQL functions and aggregates. See 4091** [sqlite3_create_function()] and [sqlite3_create_function16()] 4092** for additional information. 4093** 4094** These functions work very much like the [parameter binding] family of 4095** functions used to bind values to host parameters in prepared statements. 4096** Refer to the [SQL parameter] documentation for additional information. 4097** 4098** ^The sqlite3_result_blob() interface sets the result from 4099** an application-defined function to be the BLOB whose content is pointed 4100** to by the second parameter and which is N bytes long where N is the 4101** third parameter. 4102** 4103** ^The sqlite3_result_zeroblob() interfaces set the result of 4104** the application-defined function to be a BLOB containing all zero 4105** bytes and N bytes in size, where N is the value of the 2nd parameter. 4106** 4107** ^The sqlite3_result_double() interface sets the result from 4108** an application-defined function to be a floating point value specified 4109** by its 2nd argument. 4110** 4111** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4112** cause the implemented SQL function to throw an exception. 4113** ^SQLite uses the string pointed to by the 4114** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4115** as the text of an error message. ^SQLite interprets the error 4116** message string from sqlite3_result_error() as UTF-8. ^SQLite 4117** interprets the string from sqlite3_result_error16() as UTF-16 in native 4118** byte order. ^If the third parameter to sqlite3_result_error() 4119** or sqlite3_result_error16() is negative then SQLite takes as the error 4120** message all text up through the first zero character. 4121** ^If the third parameter to sqlite3_result_error() or 4122** sqlite3_result_error16() is non-negative then SQLite takes that many 4123** bytes (not characters) from the 2nd parameter as the error message. 4124** ^The sqlite3_result_error() and sqlite3_result_error16() 4125** routines make a private copy of the error message text before 4126** they return. Hence, the calling function can deallocate or 4127** modify the text after they return without harm. 4128** ^The sqlite3_result_error_code() function changes the error code 4129** returned by SQLite as a result of an error in a function. ^By default, 4130** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4131** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4132** 4133** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 4134** indicating that a string or BLOB is too long to represent. 4135** 4136** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 4137** indicating that a memory allocation failed. 4138** 4139** ^The sqlite3_result_int() interface sets the return value 4140** of the application-defined function to be the 32-bit signed integer 4141** value given in the 2nd argument. 4142** ^The sqlite3_result_int64() interface sets the return value 4143** of the application-defined function to be the 64-bit signed integer 4144** value given in the 2nd argument. 4145** 4146** ^The sqlite3_result_null() interface sets the return value 4147** of the application-defined function to be NULL. 4148** 4149** ^The sqlite3_result_text(), sqlite3_result_text16(), 4150** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4151** set the return value of the application-defined function to be 4152** a text string which is represented as UTF-8, UTF-16 native byte order, 4153** UTF-16 little endian, or UTF-16 big endian, respectively. 4154** ^SQLite takes the text result from the application from 4155** the 2nd parameter of the sqlite3_result_text* interfaces. 4156** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4157** is negative, then SQLite takes result text from the 2nd parameter 4158** through the first zero character. 4159** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4160** is non-negative, then as many bytes (not characters) of the text 4161** pointed to by the 2nd parameter are taken as the application-defined 4162** function result. If the 3rd parameter is non-negative, then it 4163** must be the byte offset into the string where the NUL terminator would 4164** appear if the string where NUL terminated. If any NUL characters occur 4165** in the string at a byte offset that is less than the value of the 3rd 4166** parameter, then the resulting string will contain embedded NULs and the 4167** result of expressions operating on strings with embedded NULs is undefined. 4168** ^If the 4th parameter to the sqlite3_result_text* interfaces 4169** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4170** function as the destructor on the text or BLOB result when it has 4171** finished using that result. 4172** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4173** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4174** assumes that the text or BLOB result is in constant space and does not 4175** copy the content of the parameter nor call a destructor on the content 4176** when it has finished using that result. 4177** ^If the 4th parameter to the sqlite3_result_text* interfaces 4178** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4179** then SQLite makes a copy of the result into space obtained from 4180** from [sqlite3_malloc()] before it returns. 4181** 4182** ^The sqlite3_result_value() interface sets the result of 4183** the application-defined function to be a copy the 4184** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4185** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4186** so that the [sqlite3_value] specified in the parameter may change or 4187** be deallocated after sqlite3_result_value() returns without harm. 4188** ^A [protected sqlite3_value] object may always be used where an 4189** [unprotected sqlite3_value] object is required, so either 4190** kind of [sqlite3_value] object can be used with this interface. 4191** 4192** If these routines are called from within the different thread 4193** than the one containing the application-defined function that received 4194** the [sqlite3_context] pointer, the results are undefined. 4195*/ 4196void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4197void sqlite3_result_double(sqlite3_context*, double); 4198void sqlite3_result_error(sqlite3_context*, const char*, int); 4199void sqlite3_result_error16(sqlite3_context*, const void*, int); 4200void sqlite3_result_error_toobig(sqlite3_context*); 4201void sqlite3_result_error_nomem(sqlite3_context*); 4202void sqlite3_result_error_code(sqlite3_context*, int); 4203void sqlite3_result_int(sqlite3_context*, int); 4204void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4205void sqlite3_result_null(sqlite3_context*); 4206void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4207void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4208void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4209void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4210void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4211void sqlite3_result_zeroblob(sqlite3_context*, int n); 4212 4213/* 4214** CAPI3REF: Define New Collating Sequences 4215** 4216** ^These functions add, remove, or modify a [collation] associated 4217** with the [database connection] specified as the first argument. 4218** 4219** ^The name of the collation is a UTF-8 string 4220** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4221** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4222** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4223** considered to be the same name. 4224** 4225** ^(The third argument (eTextRep) must be one of the constants: 4226** <ul> 4227** <li> [SQLITE_UTF8], 4228** <li> [SQLITE_UTF16LE], 4229** <li> [SQLITE_UTF16BE], 4230** <li> [SQLITE_UTF16], or 4231** <li> [SQLITE_UTF16_ALIGNED]. 4232** </ul>)^ 4233** ^The eTextRep argument determines the encoding of strings passed 4234** to the collating function callback, xCallback. 4235** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4236** force strings to be UTF16 with native byte order. 4237** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4238** on an even byte address. 4239** 4240** ^The fourth argument, pArg, is an application data pointer that is passed 4241** through as the first argument to the collating function callback. 4242** 4243** ^The fifth argument, xCallback, is a pointer to the collating function. 4244** ^Multiple collating functions can be registered using the same name but 4245** with different eTextRep parameters and SQLite will use whichever 4246** function requires the least amount of data transformation. 4247** ^If the xCallback argument is NULL then the collating function is 4248** deleted. ^When all collating functions having the same name are deleted, 4249** that collation is no longer usable. 4250** 4251** ^The collating function callback is invoked with a copy of the pArg 4252** application data pointer and with two strings in the encoding specified 4253** by the eTextRep argument. The collating function must return an 4254** integer that is negative, zero, or positive 4255** if the first string is less than, equal to, or greater than the second, 4256** respectively. A collating function must always return the same answer 4257** given the same inputs. If two or more collating functions are registered 4258** to the same collation name (using different eTextRep values) then all 4259** must give an equivalent answer when invoked with equivalent strings. 4260** The collating function must obey the following properties for all 4261** strings A, B, and C: 4262** 4263** <ol> 4264** <li> If A==B then B==A. 4265** <li> If A==B and B==C then A==C. 4266** <li> If A<B THEN B>A. 4267** <li> If A<B and B<C then A<C. 4268** </ol> 4269** 4270** If a collating function fails any of the above constraints and that 4271** collating function is registered and used, then the behavior of SQLite 4272** is undefined. 4273** 4274** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4275** with the addition that the xDestroy callback is invoked on pArg when 4276** the collating function is deleted. 4277** ^Collating functions are deleted when they are overridden by later 4278** calls to the collation creation functions or when the 4279** [database connection] is closed using [sqlite3_close()]. 4280** 4281** ^The xDestroy callback is <u>not</u> called if the 4282** sqlite3_create_collation_v2() function fails. Applications that invoke 4283** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4284** check the return code and dispose of the application data pointer 4285** themselves rather than expecting SQLite to deal with it for them. 4286** This is different from every other SQLite interface. The inconsistency 4287** is unfortunate but cannot be changed without breaking backwards 4288** compatibility. 4289** 4290** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4291*/ 4292int sqlite3_create_collation( 4293 sqlite3*, 4294 const char *zName, 4295 int eTextRep, 4296 void *pArg, 4297 int(*xCompare)(void*,int,const void*,int,const void*) 4298); 4299int sqlite3_create_collation_v2( 4300 sqlite3*, 4301 const char *zName, 4302 int eTextRep, 4303 void *pArg, 4304 int(*xCompare)(void*,int,const void*,int,const void*), 4305 void(*xDestroy)(void*) 4306); 4307int sqlite3_create_collation16( 4308 sqlite3*, 4309 const void *zName, 4310 int eTextRep, 4311 void *pArg, 4312 int(*xCompare)(void*,int,const void*,int,const void*) 4313); 4314 4315/* 4316** CAPI3REF: Collation Needed Callbacks 4317** 4318** ^To avoid having to register all collation sequences before a database 4319** can be used, a single callback function may be registered with the 4320** [database connection] to be invoked whenever an undefined collation 4321** sequence is required. 4322** 4323** ^If the function is registered using the sqlite3_collation_needed() API, 4324** then it is passed the names of undefined collation sequences as strings 4325** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4326** the names are passed as UTF-16 in machine native byte order. 4327** ^A call to either function replaces the existing collation-needed callback. 4328** 4329** ^(When the callback is invoked, the first argument passed is a copy 4330** of the second argument to sqlite3_collation_needed() or 4331** sqlite3_collation_needed16(). The second argument is the database 4332** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4333** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4334** sequence function required. The fourth parameter is the name of the 4335** required collation sequence.)^ 4336** 4337** The callback function should register the desired collation using 4338** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4339** [sqlite3_create_collation_v2()]. 4340*/ 4341int sqlite3_collation_needed( 4342 sqlite3*, 4343 void*, 4344 void(*)(void*,sqlite3*,int eTextRep,const char*) 4345); 4346int sqlite3_collation_needed16( 4347 sqlite3*, 4348 void*, 4349 void(*)(void*,sqlite3*,int eTextRep,const void*) 4350); 4351 4352#ifdef SQLITE_HAS_CODEC 4353/* 4354** Specify the key for an encrypted database. This routine should be 4355** called right after sqlite3_open(). 4356** 4357** The code to implement this API is not available in the public release 4358** of SQLite. 4359*/ 4360int sqlite3_key( 4361 sqlite3 *db, /* Database to be rekeyed */ 4362 const void *pKey, int nKey /* The key */ 4363); 4364 4365/* 4366** Change the key on an open database. If the current database is not 4367** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4368** database is decrypted. 4369** 4370** The code to implement this API is not available in the public release 4371** of SQLite. 4372*/ 4373int sqlite3_rekey( 4374 sqlite3 *db, /* Database to be rekeyed */ 4375 const void *pKey, int nKey /* The new key */ 4376); 4377 4378/* 4379** Specify the activation key for a SEE database. Unless 4380** activated, none of the SEE routines will work. 4381*/ 4382void sqlite3_activate_see( 4383 const char *zPassPhrase /* Activation phrase */ 4384); 4385#endif 4386 4387#ifdef SQLITE_ENABLE_CEROD 4388/* 4389** Specify the activation key for a CEROD database. Unless 4390** activated, none of the CEROD routines will work. 4391*/ 4392void sqlite3_activate_cerod( 4393 const char *zPassPhrase /* Activation phrase */ 4394); 4395#endif 4396 4397/* 4398** CAPI3REF: Suspend Execution For A Short Time 4399** 4400** The sqlite3_sleep() function causes the current thread to suspend execution 4401** for at least a number of milliseconds specified in its parameter. 4402** 4403** If the operating system does not support sleep requests with 4404** millisecond time resolution, then the time will be rounded up to 4405** the nearest second. The number of milliseconds of sleep actually 4406** requested from the operating system is returned. 4407** 4408** ^SQLite implements this interface by calling the xSleep() 4409** method of the default [sqlite3_vfs] object. If the xSleep() method 4410** of the default VFS is not implemented correctly, or not implemented at 4411** all, then the behavior of sqlite3_sleep() may deviate from the description 4412** in the previous paragraphs. 4413*/ 4414int sqlite3_sleep(int); 4415 4416/* 4417** CAPI3REF: Name Of The Folder Holding Temporary Files 4418** 4419** ^(If this global variable is made to point to a string which is 4420** the name of a folder (a.k.a. directory), then all temporary files 4421** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4422** will be placed in that directory.)^ ^If this variable 4423** is a NULL pointer, then SQLite performs a search for an appropriate 4424** temporary file directory. 4425** 4426** It is not safe to read or modify this variable in more than one 4427** thread at a time. It is not safe to read or modify this variable 4428** if a [database connection] is being used at the same time in a separate 4429** thread. 4430** It is intended that this variable be set once 4431** as part of process initialization and before any SQLite interface 4432** routines have been called and that this variable remain unchanged 4433** thereafter. 4434** 4435** ^The [temp_store_directory pragma] may modify this variable and cause 4436** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4437** the [temp_store_directory pragma] always assumes that any string 4438** that this variable points to is held in memory obtained from 4439** [sqlite3_malloc] and the pragma may attempt to free that memory 4440** using [sqlite3_free]. 4441** Hence, if this variable is modified directly, either it should be 4442** made NULL or made to point to memory obtained from [sqlite3_malloc] 4443** or else the use of the [temp_store_directory pragma] should be avoided. 4444*/ 4445SQLITE_EXTERN char *sqlite3_temp_directory; 4446 4447/* 4448** CAPI3REF: Test For Auto-Commit Mode 4449** KEYWORDS: {autocommit mode} 4450** 4451** ^The sqlite3_get_autocommit() interface returns non-zero or 4452** zero if the given database connection is or is not in autocommit mode, 4453** respectively. ^Autocommit mode is on by default. 4454** ^Autocommit mode is disabled by a [BEGIN] statement. 4455** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4456** 4457** If certain kinds of errors occur on a statement within a multi-statement 4458** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4459** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4460** transaction might be rolled back automatically. The only way to 4461** find out whether SQLite automatically rolled back the transaction after 4462** an error is to use this function. 4463** 4464** If another thread changes the autocommit status of the database 4465** connection while this routine is running, then the return value 4466** is undefined. 4467*/ 4468int sqlite3_get_autocommit(sqlite3*); 4469 4470/* 4471** CAPI3REF: Find The Database Handle Of A Prepared Statement 4472** 4473** ^The sqlite3_db_handle interface returns the [database connection] handle 4474** to which a [prepared statement] belongs. ^The [database connection] 4475** returned by sqlite3_db_handle is the same [database connection] 4476** that was the first argument 4477** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4478** create the statement in the first place. 4479*/ 4480sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4481 4482/* 4483** CAPI3REF: Return The Filename For A Database Connection 4484** 4485** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4486** associated with database N of connection D. ^The main database file 4487** has the name "main". If there is no attached database N on the database 4488** connection D, or if database N is a temporary or in-memory database, then 4489** a NULL pointer is returned. 4490** 4491** ^The filename returned by this function is the output of the 4492** xFullPathname method of the [VFS]. ^In other words, the filename 4493** will be an absolute pathname, even if the filename used 4494** to open the database originally was a URI or relative pathname. 4495*/ 4496const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4497 4498/* 4499** CAPI3REF: Determine if a database is read-only 4500** 4501** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4502** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4503** the name of a database on connection D. 4504*/ 4505int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4506 4507/* 4508** CAPI3REF: Find the next prepared statement 4509** 4510** ^This interface returns a pointer to the next [prepared statement] after 4511** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4512** then this interface returns a pointer to the first prepared statement 4513** associated with the database connection pDb. ^If no prepared statement 4514** satisfies the conditions of this routine, it returns NULL. 4515** 4516** The [database connection] pointer D in a call to 4517** [sqlite3_next_stmt(D,S)] must refer to an open database 4518** connection and in particular must not be a NULL pointer. 4519*/ 4520sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4521 4522/* 4523** CAPI3REF: Commit And Rollback Notification Callbacks 4524** 4525** ^The sqlite3_commit_hook() interface registers a callback 4526** function to be invoked whenever a transaction is [COMMIT | committed]. 4527** ^Any callback set by a previous call to sqlite3_commit_hook() 4528** for the same database connection is overridden. 4529** ^The sqlite3_rollback_hook() interface registers a callback 4530** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4531** ^Any callback set by a previous call to sqlite3_rollback_hook() 4532** for the same database connection is overridden. 4533** ^The pArg argument is passed through to the callback. 4534** ^If the callback on a commit hook function returns non-zero, 4535** then the commit is converted into a rollback. 4536** 4537** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4538** return the P argument from the previous call of the same function 4539** on the same [database connection] D, or NULL for 4540** the first call for each function on D. 4541** 4542** The commit and rollback hook callbacks are not reentrant. 4543** The callback implementation must not do anything that will modify 4544** the database connection that invoked the callback. Any actions 4545** to modify the database connection must be deferred until after the 4546** completion of the [sqlite3_step()] call that triggered the commit 4547** or rollback hook in the first place. 4548** Note that running any other SQL statements, including SELECT statements, 4549** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4550** the database connections for the meaning of "modify" in this paragraph. 4551** 4552** ^Registering a NULL function disables the callback. 4553** 4554** ^When the commit hook callback routine returns zero, the [COMMIT] 4555** operation is allowed to continue normally. ^If the commit hook 4556** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4557** ^The rollback hook is invoked on a rollback that results from a commit 4558** hook returning non-zero, just as it would be with any other rollback. 4559** 4560** ^For the purposes of this API, a transaction is said to have been 4561** rolled back if an explicit "ROLLBACK" statement is executed, or 4562** an error or constraint causes an implicit rollback to occur. 4563** ^The rollback callback is not invoked if a transaction is 4564** automatically rolled back because the database connection is closed. 4565** 4566** See also the [sqlite3_update_hook()] interface. 4567*/ 4568void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4569void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4570 4571/* 4572** CAPI3REF: Data Change Notification Callbacks 4573** 4574** ^The sqlite3_update_hook() interface registers a callback function 4575** with the [database connection] identified by the first argument 4576** to be invoked whenever a row is updated, inserted or deleted. 4577** ^Any callback set by a previous call to this function 4578** for the same database connection is overridden. 4579** 4580** ^The second argument is a pointer to the function to invoke when a 4581** row is updated, inserted or deleted. 4582** ^The first argument to the callback is a copy of the third argument 4583** to sqlite3_update_hook(). 4584** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4585** or [SQLITE_UPDATE], depending on the operation that caused the callback 4586** to be invoked. 4587** ^The third and fourth arguments to the callback contain pointers to the 4588** database and table name containing the affected row. 4589** ^The final callback parameter is the [rowid] of the row. 4590** ^In the case of an update, this is the [rowid] after the update takes place. 4591** 4592** ^(The update hook is not invoked when internal system tables are 4593** modified (i.e. sqlite_master and sqlite_sequence).)^ 4594** 4595** ^In the current implementation, the update hook 4596** is not invoked when duplication rows are deleted because of an 4597** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4598** invoked when rows are deleted using the [truncate optimization]. 4599** The exceptions defined in this paragraph might change in a future 4600** release of SQLite. 4601** 4602** The update hook implementation must not do anything that will modify 4603** the database connection that invoked the update hook. Any actions 4604** to modify the database connection must be deferred until after the 4605** completion of the [sqlite3_step()] call that triggered the update hook. 4606** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4607** database connections for the meaning of "modify" in this paragraph. 4608** 4609** ^The sqlite3_update_hook(D,C,P) function 4610** returns the P argument from the previous call 4611** on the same [database connection] D, or NULL for 4612** the first call on D. 4613** 4614** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4615** interfaces. 4616*/ 4617void *sqlite3_update_hook( 4618 sqlite3*, 4619 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4620 void* 4621); 4622 4623/* 4624** CAPI3REF: Enable Or Disable Shared Pager Cache 4625** KEYWORDS: {shared cache} 4626** 4627** ^(This routine enables or disables the sharing of the database cache 4628** and schema data structures between [database connection | connections] 4629** to the same database. Sharing is enabled if the argument is true 4630** and disabled if the argument is false.)^ 4631** 4632** ^Cache sharing is enabled and disabled for an entire process. 4633** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4634** sharing was enabled or disabled for each thread separately. 4635** 4636** ^(The cache sharing mode set by this interface effects all subsequent 4637** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4638** Existing database connections continue use the sharing mode 4639** that was in effect at the time they were opened.)^ 4640** 4641** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4642** successfully. An [error code] is returned otherwise.)^ 4643** 4644** ^Shared cache is disabled by default. But this might change in 4645** future releases of SQLite. Applications that care about shared 4646** cache setting should set it explicitly. 4647** 4648** See Also: [SQLite Shared-Cache Mode] 4649*/ 4650int sqlite3_enable_shared_cache(int); 4651 4652/* 4653** CAPI3REF: Attempt To Free Heap Memory 4654** 4655** ^The sqlite3_release_memory() interface attempts to free N bytes 4656** of heap memory by deallocating non-essential memory allocations 4657** held by the database library. Memory used to cache database 4658** pages to improve performance is an example of non-essential memory. 4659** ^sqlite3_release_memory() returns the number of bytes actually freed, 4660** which might be more or less than the amount requested. 4661** ^The sqlite3_release_memory() routine is a no-op returning zero 4662** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4663** 4664** See also: [sqlite3_db_release_memory()] 4665*/ 4666int sqlite3_release_memory(int); 4667 4668/* 4669** CAPI3REF: Free Memory Used By A Database Connection 4670** 4671** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 4672** memory as possible from database connection D. Unlike the 4673** [sqlite3_release_memory()] interface, this interface is effect even 4674** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 4675** omitted. 4676** 4677** See also: [sqlite3_release_memory()] 4678*/ 4679int sqlite3_db_release_memory(sqlite3*); 4680 4681/* 4682** CAPI3REF: Impose A Limit On Heap Size 4683** 4684** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4685** soft limit on the amount of heap memory that may be allocated by SQLite. 4686** ^SQLite strives to keep heap memory utilization below the soft heap 4687** limit by reducing the number of pages held in the page cache 4688** as heap memory usages approaches the limit. 4689** ^The soft heap limit is "soft" because even though SQLite strives to stay 4690** below the limit, it will exceed the limit rather than generate 4691** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4692** is advisory only. 4693** 4694** ^The return value from sqlite3_soft_heap_limit64() is the size of 4695** the soft heap limit prior to the call, or negative in the case of an 4696** error. ^If the argument N is negative 4697** then no change is made to the soft heap limit. Hence, the current 4698** size of the soft heap limit can be determined by invoking 4699** sqlite3_soft_heap_limit64() with a negative argument. 4700** 4701** ^If the argument N is zero then the soft heap limit is disabled. 4702** 4703** ^(The soft heap limit is not enforced in the current implementation 4704** if one or more of following conditions are true: 4705** 4706** <ul> 4707** <li> The soft heap limit is set to zero. 4708** <li> Memory accounting is disabled using a combination of the 4709** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4710** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4711** <li> An alternative page cache implementation is specified using 4712** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 4713** <li> The page cache allocates from its own memory pool supplied 4714** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4715** from the heap. 4716** </ul>)^ 4717** 4718** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4719** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4720** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4721** the soft heap limit is enforced on every memory allocation. Without 4722** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4723** when memory is allocated by the page cache. Testing suggests that because 4724** the page cache is the predominate memory user in SQLite, most 4725** applications will achieve adequate soft heap limit enforcement without 4726** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4727** 4728** The circumstances under which SQLite will enforce the soft heap limit may 4729** changes in future releases of SQLite. 4730*/ 4731sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4732 4733/* 4734** CAPI3REF: Deprecated Soft Heap Limit Interface 4735** DEPRECATED 4736** 4737** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4738** interface. This routine is provided for historical compatibility 4739** only. All new applications should use the 4740** [sqlite3_soft_heap_limit64()] interface rather than this one. 4741*/ 4742SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4743 4744 4745/* 4746** CAPI3REF: Extract Metadata About A Column Of A Table 4747** 4748** ^This routine returns metadata about a specific column of a specific 4749** database table accessible using the [database connection] handle 4750** passed as the first function argument. 4751** 4752** ^The column is identified by the second, third and fourth parameters to 4753** this function. ^The second parameter is either the name of the database 4754** (i.e. "main", "temp", or an attached database) containing the specified 4755** table or NULL. ^If it is NULL, then all attached databases are searched 4756** for the table using the same algorithm used by the database engine to 4757** resolve unqualified table references. 4758** 4759** ^The third and fourth parameters to this function are the table and column 4760** name of the desired column, respectively. Neither of these parameters 4761** may be NULL. 4762** 4763** ^Metadata is returned by writing to the memory locations passed as the 5th 4764** and subsequent parameters to this function. ^Any of these arguments may be 4765** NULL, in which case the corresponding element of metadata is omitted. 4766** 4767** ^(<blockquote> 4768** <table border="1"> 4769** <tr><th> Parameter <th> Output<br>Type <th> Description 4770** 4771** <tr><td> 5th <td> const char* <td> Data type 4772** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4773** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4774** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4775** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4776** </table> 4777** </blockquote>)^ 4778** 4779** ^The memory pointed to by the character pointers returned for the 4780** declaration type and collation sequence is valid only until the next 4781** call to any SQLite API function. 4782** 4783** ^If the specified table is actually a view, an [error code] is returned. 4784** 4785** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4786** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4787** parameters are set for the explicitly declared column. ^(If there is no 4788** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4789** parameters are set as follows: 4790** 4791** <pre> 4792** data type: "INTEGER" 4793** collation sequence: "BINARY" 4794** not null: 0 4795** primary key: 1 4796** auto increment: 0 4797** </pre>)^ 4798** 4799** ^(This function may load one or more schemas from database files. If an 4800** error occurs during this process, or if the requested table or column 4801** cannot be found, an [error code] is returned and an error message left 4802** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4803** 4804** ^This API is only available if the library was compiled with the 4805** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4806*/ 4807int sqlite3_table_column_metadata( 4808 sqlite3 *db, /* Connection handle */ 4809 const char *zDbName, /* Database name or NULL */ 4810 const char *zTableName, /* Table name */ 4811 const char *zColumnName, /* Column name */ 4812 char const **pzDataType, /* OUTPUT: Declared data type */ 4813 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4814 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4815 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4816 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4817); 4818 4819/* 4820** CAPI3REF: Load An Extension 4821** 4822** ^This interface loads an SQLite extension library from the named file. 4823** 4824** ^The sqlite3_load_extension() interface attempts to load an 4825** SQLite extension library contained in the file zFile. 4826** 4827** ^The entry point is zProc. 4828** ^zProc may be 0, in which case the name of the entry point 4829** defaults to "sqlite3_extension_init". 4830** ^The sqlite3_load_extension() interface returns 4831** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4832** ^If an error occurs and pzErrMsg is not 0, then the 4833** [sqlite3_load_extension()] interface shall attempt to 4834** fill *pzErrMsg with error message text stored in memory 4835** obtained from [sqlite3_malloc()]. The calling function 4836** should free this memory by calling [sqlite3_free()]. 4837** 4838** ^Extension loading must be enabled using 4839** [sqlite3_enable_load_extension()] prior to calling this API, 4840** otherwise an error will be returned. 4841** 4842** See also the [load_extension() SQL function]. 4843*/ 4844int sqlite3_load_extension( 4845 sqlite3 *db, /* Load the extension into this database connection */ 4846 const char *zFile, /* Name of the shared library containing extension */ 4847 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4848 char **pzErrMsg /* Put error message here if not 0 */ 4849); 4850 4851/* 4852** CAPI3REF: Enable Or Disable Extension Loading 4853** 4854** ^So as not to open security holes in older applications that are 4855** unprepared to deal with extension loading, and as a means of disabling 4856** extension loading while evaluating user-entered SQL, the following API 4857** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4858** 4859** ^Extension loading is off by default. See ticket #1863. 4860** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4861** to turn extension loading on and call it with onoff==0 to turn 4862** it back off again. 4863*/ 4864int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4865 4866/* 4867** CAPI3REF: Automatically Load Statically Linked Extensions 4868** 4869** ^This interface causes the xEntryPoint() function to be invoked for 4870** each new [database connection] that is created. The idea here is that 4871** xEntryPoint() is the entry point for a statically linked SQLite extension 4872** that is to be automatically loaded into all new database connections. 4873** 4874** ^(Even though the function prototype shows that xEntryPoint() takes 4875** no arguments and returns void, SQLite invokes xEntryPoint() with three 4876** arguments and expects and integer result as if the signature of the 4877** entry point where as follows: 4878** 4879** <blockquote><pre> 4880** int xEntryPoint( 4881** sqlite3 *db, 4882** const char **pzErrMsg, 4883** const struct sqlite3_api_routines *pThunk 4884** ); 4885** </pre></blockquote>)^ 4886** 4887** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 4888** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 4889** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 4890** is NULL before calling the xEntryPoint(). ^SQLite will invoke 4891** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 4892** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 4893** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 4894** 4895** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 4896** on the list of automatic extensions is a harmless no-op. ^No entry point 4897** will be called more than once for each database connection that is opened. 4898** 4899** See also: [sqlite3_reset_auto_extension()]. 4900*/ 4901int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4902 4903/* 4904** CAPI3REF: Reset Automatic Extension Loading 4905** 4906** ^This interface disables all automatic extensions previously 4907** registered using [sqlite3_auto_extension()]. 4908*/ 4909void sqlite3_reset_auto_extension(void); 4910 4911/* 4912** The interface to the virtual-table mechanism is currently considered 4913** to be experimental. The interface might change in incompatible ways. 4914** If this is a problem for you, do not use the interface at this time. 4915** 4916** When the virtual-table mechanism stabilizes, we will declare the 4917** interface fixed, support it indefinitely, and remove this comment. 4918*/ 4919 4920/* 4921** Structures used by the virtual table interface 4922*/ 4923typedef struct sqlite3_vtab sqlite3_vtab; 4924typedef struct sqlite3_index_info sqlite3_index_info; 4925typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4926typedef struct sqlite3_module sqlite3_module; 4927 4928/* 4929** CAPI3REF: Virtual Table Object 4930** KEYWORDS: sqlite3_module {virtual table module} 4931** 4932** This structure, sometimes called a "virtual table module", 4933** defines the implementation of a [virtual tables]. 4934** This structure consists mostly of methods for the module. 4935** 4936** ^A virtual table module is created by filling in a persistent 4937** instance of this structure and passing a pointer to that instance 4938** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4939** ^The registration remains valid until it is replaced by a different 4940** module or until the [database connection] closes. The content 4941** of this structure must not change while it is registered with 4942** any database connection. 4943*/ 4944struct sqlite3_module { 4945 int iVersion; 4946 int (*xCreate)(sqlite3*, void *pAux, 4947 int argc, const char *const*argv, 4948 sqlite3_vtab **ppVTab, char**); 4949 int (*xConnect)(sqlite3*, void *pAux, 4950 int argc, const char *const*argv, 4951 sqlite3_vtab **ppVTab, char**); 4952 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4953 int (*xDisconnect)(sqlite3_vtab *pVTab); 4954 int (*xDestroy)(sqlite3_vtab *pVTab); 4955 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4956 int (*xClose)(sqlite3_vtab_cursor*); 4957 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4958 int argc, sqlite3_value **argv); 4959 int (*xNext)(sqlite3_vtab_cursor*); 4960 int (*xEof)(sqlite3_vtab_cursor*); 4961 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4962 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4963 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4964 int (*xBegin)(sqlite3_vtab *pVTab); 4965 int (*xSync)(sqlite3_vtab *pVTab); 4966 int (*xCommit)(sqlite3_vtab *pVTab); 4967 int (*xRollback)(sqlite3_vtab *pVTab); 4968 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4969 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4970 void **ppArg); 4971 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4972 /* The methods above are in version 1 of the sqlite_module object. Those 4973 ** below are for version 2 and greater. */ 4974 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 4975 int (*xRelease)(sqlite3_vtab *pVTab, int); 4976 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 4977}; 4978 4979/* 4980** CAPI3REF: Virtual Table Indexing Information 4981** KEYWORDS: sqlite3_index_info 4982** 4983** The sqlite3_index_info structure and its substructures is used as part 4984** of the [virtual table] interface to 4985** pass information into and receive the reply from the [xBestIndex] 4986** method of a [virtual table module]. The fields under **Inputs** are the 4987** inputs to xBestIndex and are read-only. xBestIndex inserts its 4988** results into the **Outputs** fields. 4989** 4990** ^(The aConstraint[] array records WHERE clause constraints of the form: 4991** 4992** <blockquote>column OP expr</blockquote> 4993** 4994** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4995** stored in aConstraint[].op using one of the 4996** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 4997** ^(The index of the column is stored in 4998** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4999** expr on the right-hand side can be evaluated (and thus the constraint 5000** is usable) and false if it cannot.)^ 5001** 5002** ^The optimizer automatically inverts terms of the form "expr OP column" 5003** and makes other simplifications to the WHERE clause in an attempt to 5004** get as many WHERE clause terms into the form shown above as possible. 5005** ^The aConstraint[] array only reports WHERE clause terms that are 5006** relevant to the particular virtual table being queried. 5007** 5008** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5009** ^Each term of aOrderBy records a column of the ORDER BY clause. 5010** 5011** The [xBestIndex] method must fill aConstraintUsage[] with information 5012** about what parameters to pass to xFilter. ^If argvIndex>0 then 5013** the right-hand side of the corresponding aConstraint[] is evaluated 5014** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5015** is true, then the constraint is assumed to be fully handled by the 5016** virtual table and is not checked again by SQLite.)^ 5017** 5018** ^The idxNum and idxPtr values are recorded and passed into the 5019** [xFilter] method. 5020** ^[sqlite3_free()] is used to free idxPtr if and only if 5021** needToFreeIdxPtr is true. 5022** 5023** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5024** the correct order to satisfy the ORDER BY clause so that no separate 5025** sorting step is required. 5026** 5027** ^The estimatedCost value is an estimate of the cost of doing the 5028** particular lookup. A full scan of a table with N entries should have 5029** a cost of N. A binary search of a table of N entries should have a 5030** cost of approximately log(N). 5031*/ 5032struct sqlite3_index_info { 5033 /* Inputs */ 5034 int nConstraint; /* Number of entries in aConstraint */ 5035 struct sqlite3_index_constraint { 5036 int iColumn; /* Column on left-hand side of constraint */ 5037 unsigned char op; /* Constraint operator */ 5038 unsigned char usable; /* True if this constraint is usable */ 5039 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5040 } *aConstraint; /* Table of WHERE clause constraints */ 5041 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5042 struct sqlite3_index_orderby { 5043 int iColumn; /* Column number */ 5044 unsigned char desc; /* True for DESC. False for ASC. */ 5045 } *aOrderBy; /* The ORDER BY clause */ 5046 /* Outputs */ 5047 struct sqlite3_index_constraint_usage { 5048 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5049 unsigned char omit; /* Do not code a test for this constraint */ 5050 } *aConstraintUsage; 5051 int idxNum; /* Number used to identify the index */ 5052 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5053 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5054 int orderByConsumed; /* True if output is already ordered */ 5055 double estimatedCost; /* Estimated cost of using this index */ 5056}; 5057 5058/* 5059** CAPI3REF: Virtual Table Constraint Operator Codes 5060** 5061** These macros defined the allowed values for the 5062** [sqlite3_index_info].aConstraint[].op field. Each value represents 5063** an operator that is part of a constraint term in the wHERE clause of 5064** a query that uses a [virtual table]. 5065*/ 5066#define SQLITE_INDEX_CONSTRAINT_EQ 2 5067#define SQLITE_INDEX_CONSTRAINT_GT 4 5068#define SQLITE_INDEX_CONSTRAINT_LE 8 5069#define SQLITE_INDEX_CONSTRAINT_LT 16 5070#define SQLITE_INDEX_CONSTRAINT_GE 32 5071#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5072 5073/* 5074** CAPI3REF: Register A Virtual Table Implementation 5075** 5076** ^These routines are used to register a new [virtual table module] name. 5077** ^Module names must be registered before 5078** creating a new [virtual table] using the module and before using a 5079** preexisting [virtual table] for the module. 5080** 5081** ^The module name is registered on the [database connection] specified 5082** by the first parameter. ^The name of the module is given by the 5083** second parameter. ^The third parameter is a pointer to 5084** the implementation of the [virtual table module]. ^The fourth 5085** parameter is an arbitrary client data pointer that is passed through 5086** into the [xCreate] and [xConnect] methods of the virtual table module 5087** when a new virtual table is be being created or reinitialized. 5088** 5089** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5090** is a pointer to a destructor for the pClientData. ^SQLite will 5091** invoke the destructor function (if it is not NULL) when SQLite 5092** no longer needs the pClientData pointer. ^The destructor will also 5093** be invoked if the call to sqlite3_create_module_v2() fails. 5094** ^The sqlite3_create_module() 5095** interface is equivalent to sqlite3_create_module_v2() with a NULL 5096** destructor. 5097*/ 5098int sqlite3_create_module( 5099 sqlite3 *db, /* SQLite connection to register module with */ 5100 const char *zName, /* Name of the module */ 5101 const sqlite3_module *p, /* Methods for the module */ 5102 void *pClientData /* Client data for xCreate/xConnect */ 5103); 5104int sqlite3_create_module_v2( 5105 sqlite3 *db, /* SQLite connection to register module with */ 5106 const char *zName, /* Name of the module */ 5107 const sqlite3_module *p, /* Methods for the module */ 5108 void *pClientData, /* Client data for xCreate/xConnect */ 5109 void(*xDestroy)(void*) /* Module destructor function */ 5110); 5111 5112/* 5113** CAPI3REF: Virtual Table Instance Object 5114** KEYWORDS: sqlite3_vtab 5115** 5116** Every [virtual table module] implementation uses a subclass 5117** of this object to describe a particular instance 5118** of the [virtual table]. Each subclass will 5119** be tailored to the specific needs of the module implementation. 5120** The purpose of this superclass is to define certain fields that are 5121** common to all module implementations. 5122** 5123** ^Virtual tables methods can set an error message by assigning a 5124** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5125** take care that any prior string is freed by a call to [sqlite3_free()] 5126** prior to assigning a new string to zErrMsg. ^After the error message 5127** is delivered up to the client application, the string will be automatically 5128** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5129*/ 5130struct sqlite3_vtab { 5131 const sqlite3_module *pModule; /* The module for this virtual table */ 5132 int nRef; /* NO LONGER USED */ 5133 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5134 /* Virtual table implementations will typically add additional fields */ 5135}; 5136 5137/* 5138** CAPI3REF: Virtual Table Cursor Object 5139** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5140** 5141** Every [virtual table module] implementation uses a subclass of the 5142** following structure to describe cursors that point into the 5143** [virtual table] and are used 5144** to loop through the virtual table. Cursors are created using the 5145** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5146** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5147** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5148** of the module. Each module implementation will define 5149** the content of a cursor structure to suit its own needs. 5150** 5151** This superclass exists in order to define fields of the cursor that 5152** are common to all implementations. 5153*/ 5154struct sqlite3_vtab_cursor { 5155 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5156 /* Virtual table implementations will typically add additional fields */ 5157}; 5158 5159/* 5160** CAPI3REF: Declare The Schema Of A Virtual Table 5161** 5162** ^The [xCreate] and [xConnect] methods of a 5163** [virtual table module] call this interface 5164** to declare the format (the names and datatypes of the columns) of 5165** the virtual tables they implement. 5166*/ 5167int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5168 5169/* 5170** CAPI3REF: Overload A Function For A Virtual Table 5171** 5172** ^(Virtual tables can provide alternative implementations of functions 5173** using the [xFindFunction] method of the [virtual table module]. 5174** But global versions of those functions 5175** must exist in order to be overloaded.)^ 5176** 5177** ^(This API makes sure a global version of a function with a particular 5178** name and number of parameters exists. If no such function exists 5179** before this API is called, a new function is created.)^ ^The implementation 5180** of the new function always causes an exception to be thrown. So 5181** the new function is not good for anything by itself. Its only 5182** purpose is to be a placeholder function that can be overloaded 5183** by a [virtual table]. 5184*/ 5185int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5186 5187/* 5188** The interface to the virtual-table mechanism defined above (back up 5189** to a comment remarkably similar to this one) is currently considered 5190** to be experimental. The interface might change in incompatible ways. 5191** If this is a problem for you, do not use the interface at this time. 5192** 5193** When the virtual-table mechanism stabilizes, we will declare the 5194** interface fixed, support it indefinitely, and remove this comment. 5195*/ 5196 5197/* 5198** CAPI3REF: A Handle To An Open BLOB 5199** KEYWORDS: {BLOB handle} {BLOB handles} 5200** 5201** An instance of this object represents an open BLOB on which 5202** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5203** ^Objects of this type are created by [sqlite3_blob_open()] 5204** and destroyed by [sqlite3_blob_close()]. 5205** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5206** can be used to read or write small subsections of the BLOB. 5207** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5208*/ 5209typedef struct sqlite3_blob sqlite3_blob; 5210 5211/* 5212** CAPI3REF: Open A BLOB For Incremental I/O 5213** 5214** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5215** in row iRow, column zColumn, table zTable in database zDb; 5216** in other words, the same BLOB that would be selected by: 5217** 5218** <pre> 5219** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5220** </pre>)^ 5221** 5222** ^If the flags parameter is non-zero, then the BLOB is opened for read 5223** and write access. ^If it is zero, the BLOB is opened for read access. 5224** ^It is not possible to open a column that is part of an index or primary 5225** key for writing. ^If [foreign key constraints] are enabled, it is 5226** not possible to open a column that is part of a [child key] for writing. 5227** 5228** ^Note that the database name is not the filename that contains 5229** the database but rather the symbolic name of the database that 5230** appears after the AS keyword when the database is connected using [ATTACH]. 5231** ^For the main database file, the database name is "main". 5232** ^For TEMP tables, the database name is "temp". 5233** 5234** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5235** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5236** to be a null pointer.)^ 5237** ^This function sets the [database connection] error code and message 5238** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5239** functions. ^Note that the *ppBlob variable is always initialized in a 5240** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5241** regardless of the success or failure of this routine. 5242** 5243** ^(If the row that a BLOB handle points to is modified by an 5244** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5245** then the BLOB handle is marked as "expired". 5246** This is true if any column of the row is changed, even a column 5247** other than the one the BLOB handle is open on.)^ 5248** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5249** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5250** ^(Changes written into a BLOB prior to the BLOB expiring are not 5251** rolled back by the expiration of the BLOB. Such changes will eventually 5252** commit if the transaction continues to completion.)^ 5253** 5254** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5255** the opened blob. ^The size of a blob may not be changed by this 5256** interface. Use the [UPDATE] SQL command to change the size of a 5257** blob. 5258** 5259** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5260** and the built-in [zeroblob] SQL function can be used, if desired, 5261** to create an empty, zero-filled blob in which to read or write using 5262** this interface. 5263** 5264** To avoid a resource leak, every open [BLOB handle] should eventually 5265** be released by a call to [sqlite3_blob_close()]. 5266*/ 5267int sqlite3_blob_open( 5268 sqlite3*, 5269 const char *zDb, 5270 const char *zTable, 5271 const char *zColumn, 5272 sqlite3_int64 iRow, 5273 int flags, 5274 sqlite3_blob **ppBlob 5275); 5276 5277/* 5278** CAPI3REF: Move a BLOB Handle to a New Row 5279** 5280** ^This function is used to move an existing blob handle so that it points 5281** to a different row of the same database table. ^The new row is identified 5282** by the rowid value passed as the second argument. Only the row can be 5283** changed. ^The database, table and column on which the blob handle is open 5284** remain the same. Moving an existing blob handle to a new row can be 5285** faster than closing the existing handle and opening a new one. 5286** 5287** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5288** it must exist and there must be either a blob or text value stored in 5289** the nominated column.)^ ^If the new row is not present in the table, or if 5290** it does not contain a blob or text value, or if another error occurs, an 5291** SQLite error code is returned and the blob handle is considered aborted. 5292** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5293** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5294** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5295** always returns zero. 5296** 5297** ^This function sets the database handle error code and message. 5298*/ 5299SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5300 5301/* 5302** CAPI3REF: Close A BLOB Handle 5303** 5304** ^Closes an open [BLOB handle]. 5305** 5306** ^Closing a BLOB shall cause the current transaction to commit 5307** if there are no other BLOBs, no pending prepared statements, and the 5308** database connection is in [autocommit mode]. 5309** ^If any writes were made to the BLOB, they might be held in cache 5310** until the close operation if they will fit. 5311** 5312** ^(Closing the BLOB often forces the changes 5313** out to disk and so if any I/O errors occur, they will likely occur 5314** at the time when the BLOB is closed. Any errors that occur during 5315** closing are reported as a non-zero return value.)^ 5316** 5317** ^(The BLOB is closed unconditionally. Even if this routine returns 5318** an error code, the BLOB is still closed.)^ 5319** 5320** ^Calling this routine with a null pointer (such as would be returned 5321** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5322*/ 5323int sqlite3_blob_close(sqlite3_blob *); 5324 5325/* 5326** CAPI3REF: Return The Size Of An Open BLOB 5327** 5328** ^Returns the size in bytes of the BLOB accessible via the 5329** successfully opened [BLOB handle] in its only argument. ^The 5330** incremental blob I/O routines can only read or overwriting existing 5331** blob content; they cannot change the size of a blob. 5332** 5333** This routine only works on a [BLOB handle] which has been created 5334** by a prior successful call to [sqlite3_blob_open()] and which has not 5335** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5336** to this routine results in undefined and probably undesirable behavior. 5337*/ 5338int sqlite3_blob_bytes(sqlite3_blob *); 5339 5340/* 5341** CAPI3REF: Read Data From A BLOB Incrementally 5342** 5343** ^(This function is used to read data from an open [BLOB handle] into a 5344** caller-supplied buffer. N bytes of data are copied into buffer Z 5345** from the open BLOB, starting at offset iOffset.)^ 5346** 5347** ^If offset iOffset is less than N bytes from the end of the BLOB, 5348** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5349** less than zero, [SQLITE_ERROR] is returned and no data is read. 5350** ^The size of the blob (and hence the maximum value of N+iOffset) 5351** can be determined using the [sqlite3_blob_bytes()] interface. 5352** 5353** ^An attempt to read from an expired [BLOB handle] fails with an 5354** error code of [SQLITE_ABORT]. 5355** 5356** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5357** Otherwise, an [error code] or an [extended error code] is returned.)^ 5358** 5359** This routine only works on a [BLOB handle] which has been created 5360** by a prior successful call to [sqlite3_blob_open()] and which has not 5361** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5362** to this routine results in undefined and probably undesirable behavior. 5363** 5364** See also: [sqlite3_blob_write()]. 5365*/ 5366int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5367 5368/* 5369** CAPI3REF: Write Data Into A BLOB Incrementally 5370** 5371** ^This function is used to write data into an open [BLOB handle] from a 5372** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5373** into the open BLOB, starting at offset iOffset. 5374** 5375** ^If the [BLOB handle] passed as the first argument was not opened for 5376** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5377** this function returns [SQLITE_READONLY]. 5378** 5379** ^This function may only modify the contents of the BLOB; it is 5380** not possible to increase the size of a BLOB using this API. 5381** ^If offset iOffset is less than N bytes from the end of the BLOB, 5382** [SQLITE_ERROR] is returned and no data is written. ^If N is 5383** less than zero [SQLITE_ERROR] is returned and no data is written. 5384** The size of the BLOB (and hence the maximum value of N+iOffset) 5385** can be determined using the [sqlite3_blob_bytes()] interface. 5386** 5387** ^An attempt to write to an expired [BLOB handle] fails with an 5388** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5389** before the [BLOB handle] expired are not rolled back by the 5390** expiration of the handle, though of course those changes might 5391** have been overwritten by the statement that expired the BLOB handle 5392** or by other independent statements. 5393** 5394** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5395** Otherwise, an [error code] or an [extended error code] is returned.)^ 5396** 5397** This routine only works on a [BLOB handle] which has been created 5398** by a prior successful call to [sqlite3_blob_open()] and which has not 5399** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5400** to this routine results in undefined and probably undesirable behavior. 5401** 5402** See also: [sqlite3_blob_read()]. 5403*/ 5404int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5405 5406/* 5407** CAPI3REF: Virtual File System Objects 5408** 5409** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5410** that SQLite uses to interact 5411** with the underlying operating system. Most SQLite builds come with a 5412** single default VFS that is appropriate for the host computer. 5413** New VFSes can be registered and existing VFSes can be unregistered. 5414** The following interfaces are provided. 5415** 5416** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5417** ^Names are case sensitive. 5418** ^Names are zero-terminated UTF-8 strings. 5419** ^If there is no match, a NULL pointer is returned. 5420** ^If zVfsName is NULL then the default VFS is returned. 5421** 5422** ^New VFSes are registered with sqlite3_vfs_register(). 5423** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5424** ^The same VFS can be registered multiple times without injury. 5425** ^To make an existing VFS into the default VFS, register it again 5426** with the makeDflt flag set. If two different VFSes with the 5427** same name are registered, the behavior is undefined. If a 5428** VFS is registered with a name that is NULL or an empty string, 5429** then the behavior is undefined. 5430** 5431** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5432** ^(If the default VFS is unregistered, another VFS is chosen as 5433** the default. The choice for the new VFS is arbitrary.)^ 5434*/ 5435sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5436int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5437int sqlite3_vfs_unregister(sqlite3_vfs*); 5438 5439/* 5440** CAPI3REF: Mutexes 5441** 5442** The SQLite core uses these routines for thread 5443** synchronization. Though they are intended for internal 5444** use by SQLite, code that links against SQLite is 5445** permitted to use any of these routines. 5446** 5447** The SQLite source code contains multiple implementations 5448** of these mutex routines. An appropriate implementation 5449** is selected automatically at compile-time. ^(The following 5450** implementations are available in the SQLite core: 5451** 5452** <ul> 5453** <li> SQLITE_MUTEX_OS2 5454** <li> SQLITE_MUTEX_PTHREADS 5455** <li> SQLITE_MUTEX_W32 5456** <li> SQLITE_MUTEX_NOOP 5457** </ul>)^ 5458** 5459** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5460** that does no real locking and is appropriate for use in 5461** a single-threaded application. ^The SQLITE_MUTEX_OS2, 5462** SQLITE_MUTEX_PTHREADS, and SQLITE_MUTEX_W32 implementations 5463** are appropriate for use on OS/2, Unix, and Windows. 5464** 5465** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5466** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5467** implementation is included with the library. In this case the 5468** application must supply a custom mutex implementation using the 5469** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5470** before calling sqlite3_initialize() or any other public sqlite3_ 5471** function that calls sqlite3_initialize().)^ 5472** 5473** ^The sqlite3_mutex_alloc() routine allocates a new 5474** mutex and returns a pointer to it. ^If it returns NULL 5475** that means that a mutex could not be allocated. ^SQLite 5476** will unwind its stack and return an error. ^(The argument 5477** to sqlite3_mutex_alloc() is one of these integer constants: 5478** 5479** <ul> 5480** <li> SQLITE_MUTEX_FAST 5481** <li> SQLITE_MUTEX_RECURSIVE 5482** <li> SQLITE_MUTEX_STATIC_MASTER 5483** <li> SQLITE_MUTEX_STATIC_MEM 5484** <li> SQLITE_MUTEX_STATIC_MEM2 5485** <li> SQLITE_MUTEX_STATIC_PRNG 5486** <li> SQLITE_MUTEX_STATIC_LRU 5487** <li> SQLITE_MUTEX_STATIC_LRU2 5488** </ul>)^ 5489** 5490** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5491** cause sqlite3_mutex_alloc() to create 5492** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5493** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5494** The mutex implementation does not need to make a distinction 5495** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5496** not want to. ^SQLite will only request a recursive mutex in 5497** cases where it really needs one. ^If a faster non-recursive mutex 5498** implementation is available on the host platform, the mutex subsystem 5499** might return such a mutex in response to SQLITE_MUTEX_FAST. 5500** 5501** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5502** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5503** a pointer to a static preexisting mutex. ^Six static mutexes are 5504** used by the current version of SQLite. Future versions of SQLite 5505** may add additional static mutexes. Static mutexes are for internal 5506** use by SQLite only. Applications that use SQLite mutexes should 5507** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5508** SQLITE_MUTEX_RECURSIVE. 5509** 5510** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5511** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5512** returns a different mutex on every call. ^But for the static 5513** mutex types, the same mutex is returned on every call that has 5514** the same type number. 5515** 5516** ^The sqlite3_mutex_free() routine deallocates a previously 5517** allocated dynamic mutex. ^SQLite is careful to deallocate every 5518** dynamic mutex that it allocates. The dynamic mutexes must not be in 5519** use when they are deallocated. Attempting to deallocate a static 5520** mutex results in undefined behavior. ^SQLite never deallocates 5521** a static mutex. 5522** 5523** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5524** to enter a mutex. ^If another thread is already within the mutex, 5525** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5526** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5527** upon successful entry. ^(Mutexes created using 5528** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5529** In such cases the, 5530** mutex must be exited an equal number of times before another thread 5531** can enter.)^ ^(If the same thread tries to enter any other 5532** kind of mutex more than once, the behavior is undefined. 5533** SQLite will never exhibit 5534** such behavior in its own use of mutexes.)^ 5535** 5536** ^(Some systems (for example, Windows 95) do not support the operation 5537** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5538** will always return SQLITE_BUSY. The SQLite core only ever uses 5539** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5540** 5541** ^The sqlite3_mutex_leave() routine exits a mutex that was 5542** previously entered by the same thread. ^(The behavior 5543** is undefined if the mutex is not currently entered by the 5544** calling thread or is not currently allocated. SQLite will 5545** never do either.)^ 5546** 5547** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5548** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5549** behave as no-ops. 5550** 5551** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5552*/ 5553sqlite3_mutex *sqlite3_mutex_alloc(int); 5554void sqlite3_mutex_free(sqlite3_mutex*); 5555void sqlite3_mutex_enter(sqlite3_mutex*); 5556int sqlite3_mutex_try(sqlite3_mutex*); 5557void sqlite3_mutex_leave(sqlite3_mutex*); 5558 5559/* 5560** CAPI3REF: Mutex Methods Object 5561** 5562** An instance of this structure defines the low-level routines 5563** used to allocate and use mutexes. 5564** 5565** Usually, the default mutex implementations provided by SQLite are 5566** sufficient, however the user has the option of substituting a custom 5567** implementation for specialized deployments or systems for which SQLite 5568** does not provide a suitable implementation. In this case, the user 5569** creates and populates an instance of this structure to pass 5570** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5571** Additionally, an instance of this structure can be used as an 5572** output variable when querying the system for the current mutex 5573** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5574** 5575** ^The xMutexInit method defined by this structure is invoked as 5576** part of system initialization by the sqlite3_initialize() function. 5577** ^The xMutexInit routine is called by SQLite exactly once for each 5578** effective call to [sqlite3_initialize()]. 5579** 5580** ^The xMutexEnd method defined by this structure is invoked as 5581** part of system shutdown by the sqlite3_shutdown() function. The 5582** implementation of this method is expected to release all outstanding 5583** resources obtained by the mutex methods implementation, especially 5584** those obtained by the xMutexInit method. ^The xMutexEnd() 5585** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5586** 5587** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5588** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5589** xMutexNotheld) implement the following interfaces (respectively): 5590** 5591** <ul> 5592** <li> [sqlite3_mutex_alloc()] </li> 5593** <li> [sqlite3_mutex_free()] </li> 5594** <li> [sqlite3_mutex_enter()] </li> 5595** <li> [sqlite3_mutex_try()] </li> 5596** <li> [sqlite3_mutex_leave()] </li> 5597** <li> [sqlite3_mutex_held()] </li> 5598** <li> [sqlite3_mutex_notheld()] </li> 5599** </ul>)^ 5600** 5601** The only difference is that the public sqlite3_XXX functions enumerated 5602** above silently ignore any invocations that pass a NULL pointer instead 5603** of a valid mutex handle. The implementations of the methods defined 5604** by this structure are not required to handle this case, the results 5605** of passing a NULL pointer instead of a valid mutex handle are undefined 5606** (i.e. it is acceptable to provide an implementation that segfaults if 5607** it is passed a NULL pointer). 5608** 5609** The xMutexInit() method must be threadsafe. ^It must be harmless to 5610** invoke xMutexInit() multiple times within the same process and without 5611** intervening calls to xMutexEnd(). Second and subsequent calls to 5612** xMutexInit() must be no-ops. 5613** 5614** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5615** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5616** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5617** memory allocation for a fast or recursive mutex. 5618** 5619** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5620** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5621** If xMutexInit fails in any way, it is expected to clean up after itself 5622** prior to returning. 5623*/ 5624typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5625struct sqlite3_mutex_methods { 5626 int (*xMutexInit)(void); 5627 int (*xMutexEnd)(void); 5628 sqlite3_mutex *(*xMutexAlloc)(int); 5629 void (*xMutexFree)(sqlite3_mutex *); 5630 void (*xMutexEnter)(sqlite3_mutex *); 5631 int (*xMutexTry)(sqlite3_mutex *); 5632 void (*xMutexLeave)(sqlite3_mutex *); 5633 int (*xMutexHeld)(sqlite3_mutex *); 5634 int (*xMutexNotheld)(sqlite3_mutex *); 5635}; 5636 5637/* 5638** CAPI3REF: Mutex Verification Routines 5639** 5640** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5641** are intended for use inside assert() statements. ^The SQLite core 5642** never uses these routines except inside an assert() and applications 5643** are advised to follow the lead of the core. ^The SQLite core only 5644** provides implementations for these routines when it is compiled 5645** with the SQLITE_DEBUG flag. ^External mutex implementations 5646** are only required to provide these routines if SQLITE_DEBUG is 5647** defined and if NDEBUG is not defined. 5648** 5649** ^These routines should return true if the mutex in their argument 5650** is held or not held, respectively, by the calling thread. 5651** 5652** ^The implementation is not required to provide versions of these 5653** routines that actually work. If the implementation does not provide working 5654** versions of these routines, it should at least provide stubs that always 5655** return true so that one does not get spurious assertion failures. 5656** 5657** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5658** the routine should return 1. This seems counter-intuitive since 5659** clearly the mutex cannot be held if it does not exist. But 5660** the reason the mutex does not exist is because the build is not 5661** using mutexes. And we do not want the assert() containing the 5662** call to sqlite3_mutex_held() to fail, so a non-zero return is 5663** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5664** interface should also return 1 when given a NULL pointer. 5665*/ 5666#ifndef NDEBUG 5667int sqlite3_mutex_held(sqlite3_mutex*); 5668int sqlite3_mutex_notheld(sqlite3_mutex*); 5669#endif 5670 5671/* 5672** CAPI3REF: Mutex Types 5673** 5674** The [sqlite3_mutex_alloc()] interface takes a single argument 5675** which is one of these integer constants. 5676** 5677** The set of static mutexes may change from one SQLite release to the 5678** next. Applications that override the built-in mutex logic must be 5679** prepared to accommodate additional static mutexes. 5680*/ 5681#define SQLITE_MUTEX_FAST 0 5682#define SQLITE_MUTEX_RECURSIVE 1 5683#define SQLITE_MUTEX_STATIC_MASTER 2 5684#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5685#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5686#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5687#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5688#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5689#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5690#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5691 5692/* 5693** CAPI3REF: Retrieve the mutex for a database connection 5694** 5695** ^This interface returns a pointer the [sqlite3_mutex] object that 5696** serializes access to the [database connection] given in the argument 5697** when the [threading mode] is Serialized. 5698** ^If the [threading mode] is Single-thread or Multi-thread then this 5699** routine returns a NULL pointer. 5700*/ 5701sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5702 5703/* 5704** CAPI3REF: Low-Level Control Of Database Files 5705** 5706** ^The [sqlite3_file_control()] interface makes a direct call to the 5707** xFileControl method for the [sqlite3_io_methods] object associated 5708** with a particular database identified by the second argument. ^The 5709** name of the database is "main" for the main database or "temp" for the 5710** TEMP database, or the name that appears after the AS keyword for 5711** databases that are added using the [ATTACH] SQL command. 5712** ^A NULL pointer can be used in place of "main" to refer to the 5713** main database file. 5714** ^The third and fourth parameters to this routine 5715** are passed directly through to the second and third parameters of 5716** the xFileControl method. ^The return value of the xFileControl 5717** method becomes the return value of this routine. 5718** 5719** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5720** a pointer to the underlying [sqlite3_file] object to be written into 5721** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5722** case is a short-circuit path which does not actually invoke the 5723** underlying sqlite3_io_methods.xFileControl method. 5724** 5725** ^If the second parameter (zDbName) does not match the name of any 5726** open database file, then SQLITE_ERROR is returned. ^This error 5727** code is not remembered and will not be recalled by [sqlite3_errcode()] 5728** or [sqlite3_errmsg()]. The underlying xFileControl method might 5729** also return SQLITE_ERROR. There is no way to distinguish between 5730** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5731** xFileControl method. 5732** 5733** See also: [SQLITE_FCNTL_LOCKSTATE] 5734*/ 5735int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5736 5737/* 5738** CAPI3REF: Testing Interface 5739** 5740** ^The sqlite3_test_control() interface is used to read out internal 5741** state of SQLite and to inject faults into SQLite for testing 5742** purposes. ^The first parameter is an operation code that determines 5743** the number, meaning, and operation of all subsequent parameters. 5744** 5745** This interface is not for use by applications. It exists solely 5746** for verifying the correct operation of the SQLite library. Depending 5747** on how the SQLite library is compiled, this interface might not exist. 5748** 5749** The details of the operation codes, their meanings, the parameters 5750** they take, and what they do are all subject to change without notice. 5751** Unlike most of the SQLite API, this function is not guaranteed to 5752** operate consistently from one release to the next. 5753*/ 5754int sqlite3_test_control(int op, ...); 5755 5756/* 5757** CAPI3REF: Testing Interface Operation Codes 5758** 5759** These constants are the valid operation code parameters used 5760** as the first argument to [sqlite3_test_control()]. 5761** 5762** These parameters and their meanings are subject to change 5763** without notice. These values are for testing purposes only. 5764** Applications should not use any of these parameters or the 5765** [sqlite3_test_control()] interface. 5766*/ 5767#define SQLITE_TESTCTRL_FIRST 5 5768#define SQLITE_TESTCTRL_PRNG_SAVE 5 5769#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5770#define SQLITE_TESTCTRL_PRNG_RESET 7 5771#define SQLITE_TESTCTRL_BITVEC_TEST 8 5772#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5773#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5774#define SQLITE_TESTCTRL_PENDING_BYTE 11 5775#define SQLITE_TESTCTRL_ASSERT 12 5776#define SQLITE_TESTCTRL_ALWAYS 13 5777#define SQLITE_TESTCTRL_RESERVE 14 5778#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5779#define SQLITE_TESTCTRL_ISKEYWORD 16 5780#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 5781#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 5782#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 5783#define SQLITE_TESTCTRL_LAST 19 5784 5785/* 5786** CAPI3REF: SQLite Runtime Status 5787** 5788** ^This interface is used to retrieve runtime status information 5789** about the performance of SQLite, and optionally to reset various 5790** highwater marks. ^The first argument is an integer code for 5791** the specific parameter to measure. ^(Recognized integer codes 5792** are of the form [status parameters | SQLITE_STATUS_...].)^ 5793** ^The current value of the parameter is returned into *pCurrent. 5794** ^The highest recorded value is returned in *pHighwater. ^If the 5795** resetFlag is true, then the highest record value is reset after 5796** *pHighwater is written. ^(Some parameters do not record the highest 5797** value. For those parameters 5798** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5799** ^(Other parameters record only the highwater mark and not the current 5800** value. For these latter parameters nothing is written into *pCurrent.)^ 5801** 5802** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5803** non-zero [error code] on failure. 5804** 5805** This routine is threadsafe but is not atomic. This routine can be 5806** called while other threads are running the same or different SQLite 5807** interfaces. However the values returned in *pCurrent and 5808** *pHighwater reflect the status of SQLite at different points in time 5809** and it is possible that another thread might change the parameter 5810** in between the times when *pCurrent and *pHighwater are written. 5811** 5812** See also: [sqlite3_db_status()] 5813*/ 5814int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5815 5816 5817/* 5818** CAPI3REF: Status Parameters 5819** KEYWORDS: {status parameters} 5820** 5821** These integer constants designate various run-time status parameters 5822** that can be returned by [sqlite3_status()]. 5823** 5824** <dl> 5825** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5826** <dd>This parameter is the current amount of memory checked out 5827** using [sqlite3_malloc()], either directly or indirectly. The 5828** figure includes calls made to [sqlite3_malloc()] by the application 5829** and internal memory usage by the SQLite library. Scratch memory 5830** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5831** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5832** this parameter. The amount returned is the sum of the allocation 5833** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5834** 5835** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5836** <dd>This parameter records the largest memory allocation request 5837** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5838** internal equivalents). Only the value returned in the 5839** *pHighwater parameter to [sqlite3_status()] is of interest. 5840** The value written into the *pCurrent parameter is undefined.</dd>)^ 5841** 5842** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5843** <dd>This parameter records the number of separate memory allocations 5844** currently checked out.</dd>)^ 5845** 5846** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5847** <dd>This parameter returns the number of pages used out of the 5848** [pagecache memory allocator] that was configured using 5849** [SQLITE_CONFIG_PAGECACHE]. The 5850** value returned is in pages, not in bytes.</dd>)^ 5851** 5852** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 5853** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5854** <dd>This parameter returns the number of bytes of page cache 5855** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 5856** buffer and where forced to overflow to [sqlite3_malloc()]. The 5857** returned value includes allocations that overflowed because they 5858** where too large (they were larger than the "sz" parameter to 5859** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5860** no space was left in the page cache.</dd>)^ 5861** 5862** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5863** <dd>This parameter records the largest memory allocation request 5864** handed to [pagecache memory allocator]. Only the value returned in the 5865** *pHighwater parameter to [sqlite3_status()] is of interest. 5866** The value written into the *pCurrent parameter is undefined.</dd>)^ 5867** 5868** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5869** <dd>This parameter returns the number of allocations used out of the 5870** [scratch memory allocator] configured using 5871** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5872** in bytes. Since a single thread may only have one scratch allocation 5873** outstanding at time, this parameter also reports the number of threads 5874** using scratch memory at the same time.</dd>)^ 5875** 5876** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5877** <dd>This parameter returns the number of bytes of scratch memory 5878** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 5879** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5880** returned include overflows because the requested allocation was too 5881** larger (that is, because the requested allocation was larger than the 5882** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5883** slots were available. 5884** </dd>)^ 5885** 5886** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5887** <dd>This parameter records the largest memory allocation request 5888** handed to [scratch memory allocator]. Only the value returned in the 5889** *pHighwater parameter to [sqlite3_status()] is of interest. 5890** The value written into the *pCurrent parameter is undefined.</dd>)^ 5891** 5892** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5893** <dd>This parameter records the deepest parser stack. It is only 5894** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5895** </dl> 5896** 5897** New status parameters may be added from time to time. 5898*/ 5899#define SQLITE_STATUS_MEMORY_USED 0 5900#define SQLITE_STATUS_PAGECACHE_USED 1 5901#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5902#define SQLITE_STATUS_SCRATCH_USED 3 5903#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5904#define SQLITE_STATUS_MALLOC_SIZE 5 5905#define SQLITE_STATUS_PARSER_STACK 6 5906#define SQLITE_STATUS_PAGECACHE_SIZE 7 5907#define SQLITE_STATUS_SCRATCH_SIZE 8 5908#define SQLITE_STATUS_MALLOC_COUNT 9 5909 5910/* 5911** CAPI3REF: Database Connection Status 5912** 5913** ^This interface is used to retrieve runtime status information 5914** about a single [database connection]. ^The first argument is the 5915** database connection object to be interrogated. ^The second argument 5916** is an integer constant, taken from the set of 5917** [SQLITE_DBSTATUS options], that 5918** determines the parameter to interrogate. The set of 5919** [SQLITE_DBSTATUS options] is likely 5920** to grow in future releases of SQLite. 5921** 5922** ^The current value of the requested parameter is written into *pCur 5923** and the highest instantaneous value is written into *pHiwtr. ^If 5924** the resetFlg is true, then the highest instantaneous value is 5925** reset back down to the current value. 5926** 5927** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5928** non-zero [error code] on failure. 5929** 5930** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5931*/ 5932int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5933 5934/* 5935** CAPI3REF: Status Parameters for database connections 5936** KEYWORDS: {SQLITE_DBSTATUS options} 5937** 5938** These constants are the available integer "verbs" that can be passed as 5939** the second argument to the [sqlite3_db_status()] interface. 5940** 5941** New verbs may be added in future releases of SQLite. Existing verbs 5942** might be discontinued. Applications should check the return code from 5943** [sqlite3_db_status()] to make sure that the call worked. 5944** The [sqlite3_db_status()] interface will return a non-zero error code 5945** if a discontinued or unsupported verb is invoked. 5946** 5947** <dl> 5948** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5949** <dd>This parameter returns the number of lookaside memory slots currently 5950** checked out.</dd>)^ 5951** 5952** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 5953** <dd>This parameter returns the number malloc attempts that were 5954** satisfied using lookaside memory. Only the high-water value is meaningful; 5955** the current value is always zero.)^ 5956** 5957** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 5958** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 5959** <dd>This parameter returns the number malloc attempts that might have 5960** been satisfied using lookaside memory but failed due to the amount of 5961** memory requested being larger than the lookaside slot size. 5962** Only the high-water value is meaningful; 5963** the current value is always zero.)^ 5964** 5965** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 5966** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 5967** <dd>This parameter returns the number malloc attempts that might have 5968** been satisfied using lookaside memory but failed due to all lookaside 5969** memory already being in use. 5970** Only the high-water value is meaningful; 5971** the current value is always zero.)^ 5972** 5973** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5974** <dd>This parameter returns the approximate number of of bytes of heap 5975** memory used by all pager caches associated with the database connection.)^ 5976** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5977** 5978** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5979** <dd>This parameter returns the approximate number of of bytes of heap 5980** memory used to store the schema for all databases associated 5981** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5982** ^The full amount of memory used by the schemas is reported, even if the 5983** schema memory is shared with other database connections due to 5984** [shared cache mode] being enabled. 5985** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5986** 5987** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5988** <dd>This parameter returns the approximate number of of bytes of heap 5989** and lookaside memory used by all prepared statements associated with 5990** the database connection.)^ 5991** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5992** </dd> 5993** 5994** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 5995** <dd>This parameter returns the number of pager cache hits that have 5996** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 5997** is always 0. 5998** </dd> 5999** 6000** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6001** <dd>This parameter returns the number of pager cache misses that have 6002** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6003** is always 0. 6004** </dd> 6005** 6006** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6007** <dd>This parameter returns the number of dirty cache entries that have 6008** been written to disk. Specifically, the number of pages written to the 6009** wal file in wal mode databases, or the number of pages written to the 6010** database file in rollback mode databases. Any pages written as part of 6011** transaction rollback or database recovery operations are not included. 6012** If an IO or other error occurs while writing a page to disk, the effect 6013** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6014** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6015** </dd> 6016** </dl> 6017*/ 6018#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6019#define SQLITE_DBSTATUS_CACHE_USED 1 6020#define SQLITE_DBSTATUS_SCHEMA_USED 2 6021#define SQLITE_DBSTATUS_STMT_USED 3 6022#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6023#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6024#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6025#define SQLITE_DBSTATUS_CACHE_HIT 7 6026#define SQLITE_DBSTATUS_CACHE_MISS 8 6027#define SQLITE_DBSTATUS_CACHE_WRITE 9 6028#define SQLITE_DBSTATUS_MAX 9 /* Largest defined DBSTATUS */ 6029 6030 6031/* 6032** CAPI3REF: Prepared Statement Status 6033** 6034** ^(Each prepared statement maintains various 6035** [SQLITE_STMTSTATUS counters] that measure the number 6036** of times it has performed specific operations.)^ These counters can 6037** be used to monitor the performance characteristics of the prepared 6038** statements. For example, if the number of table steps greatly exceeds 6039** the number of table searches or result rows, that would tend to indicate 6040** that the prepared statement is using a full table scan rather than 6041** an index. 6042** 6043** ^(This interface is used to retrieve and reset counter values from 6044** a [prepared statement]. The first argument is the prepared statement 6045** object to be interrogated. The second argument 6046** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6047** to be interrogated.)^ 6048** ^The current value of the requested counter is returned. 6049** ^If the resetFlg is true, then the counter is reset to zero after this 6050** interface call returns. 6051** 6052** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6053*/ 6054int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6055 6056/* 6057** CAPI3REF: Status Parameters for prepared statements 6058** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6059** 6060** These preprocessor macros define integer codes that name counter 6061** values associated with the [sqlite3_stmt_status()] interface. 6062** The meanings of the various counters are as follows: 6063** 6064** <dl> 6065** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6066** <dd>^This is the number of times that SQLite has stepped forward in 6067** a table as part of a full table scan. Large numbers for this counter 6068** may indicate opportunities for performance improvement through 6069** careful use of indices.</dd> 6070** 6071** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6072** <dd>^This is the number of sort operations that have occurred. 6073** A non-zero value in this counter may indicate an opportunity to 6074** improvement performance through careful use of indices.</dd> 6075** 6076** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6077** <dd>^This is the number of rows inserted into transient indices that 6078** were created automatically in order to help joins run faster. 6079** A non-zero value in this counter may indicate an opportunity to 6080** improvement performance by adding permanent indices that do not 6081** need to be reinitialized each time the statement is run.</dd> 6082** </dl> 6083*/ 6084#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6085#define SQLITE_STMTSTATUS_SORT 2 6086#define SQLITE_STMTSTATUS_AUTOINDEX 3 6087 6088/* 6089** CAPI3REF: Custom Page Cache Object 6090** 6091** The sqlite3_pcache type is opaque. It is implemented by 6092** the pluggable module. The SQLite core has no knowledge of 6093** its size or internal structure and never deals with the 6094** sqlite3_pcache object except by holding and passing pointers 6095** to the object. 6096** 6097** See [sqlite3_pcache_methods2] for additional information. 6098*/ 6099typedef struct sqlite3_pcache sqlite3_pcache; 6100 6101/* 6102** CAPI3REF: Custom Page Cache Object 6103** 6104** The sqlite3_pcache_page object represents a single page in the 6105** page cache. The page cache will allocate instances of this 6106** object. Various methods of the page cache use pointers to instances 6107** of this object as parameters or as their return value. 6108** 6109** See [sqlite3_pcache_methods2] for additional information. 6110*/ 6111typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6112struct sqlite3_pcache_page { 6113 void *pBuf; /* The content of the page */ 6114 void *pExtra; /* Extra information associated with the page */ 6115}; 6116 6117/* 6118** CAPI3REF: Application Defined Page Cache. 6119** KEYWORDS: {page cache} 6120** 6121** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6122** register an alternative page cache implementation by passing in an 6123** instance of the sqlite3_pcache_methods2 structure.)^ 6124** In many applications, most of the heap memory allocated by 6125** SQLite is used for the page cache. 6126** By implementing a 6127** custom page cache using this API, an application can better control 6128** the amount of memory consumed by SQLite, the way in which 6129** that memory is allocated and released, and the policies used to 6130** determine exactly which parts of a database file are cached and for 6131** how long. 6132** 6133** The alternative page cache mechanism is an 6134** extreme measure that is only needed by the most demanding applications. 6135** The built-in page cache is recommended for most uses. 6136** 6137** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6138** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6139** the application may discard the parameter after the call to 6140** [sqlite3_config()] returns.)^ 6141** 6142** [[the xInit() page cache method]] 6143** ^(The xInit() method is called once for each effective 6144** call to [sqlite3_initialize()])^ 6145** (usually only once during the lifetime of the process). ^(The xInit() 6146** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6147** The intent of the xInit() method is to set up global data structures 6148** required by the custom page cache implementation. 6149** ^(If the xInit() method is NULL, then the 6150** built-in default page cache is used instead of the application defined 6151** page cache.)^ 6152** 6153** [[the xShutdown() page cache method]] 6154** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6155** It can be used to clean up 6156** any outstanding resources before process shutdown, if required. 6157** ^The xShutdown() method may be NULL. 6158** 6159** ^SQLite automatically serializes calls to the xInit method, 6160** so the xInit method need not be threadsafe. ^The 6161** xShutdown method is only called from [sqlite3_shutdown()] so it does 6162** not need to be threadsafe either. All other methods must be threadsafe 6163** in multithreaded applications. 6164** 6165** ^SQLite will never invoke xInit() more than once without an intervening 6166** call to xShutdown(). 6167** 6168** [[the xCreate() page cache methods]] 6169** ^SQLite invokes the xCreate() method to construct a new cache instance. 6170** SQLite will typically create one cache instance for each open database file, 6171** though this is not guaranteed. ^The 6172** first parameter, szPage, is the size in bytes of the pages that must 6173** be allocated by the cache. ^szPage will always a power of two. ^The 6174** second parameter szExtra is a number of bytes of extra storage 6175** associated with each page cache entry. ^The szExtra parameter will 6176** a number less than 250. SQLite will use the 6177** extra szExtra bytes on each page to store metadata about the underlying 6178** database page on disk. The value passed into szExtra depends 6179** on the SQLite version, the target platform, and how SQLite was compiled. 6180** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6181** created will be used to cache database pages of a file stored on disk, or 6182** false if it is used for an in-memory database. The cache implementation 6183** does not have to do anything special based with the value of bPurgeable; 6184** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6185** never invoke xUnpin() except to deliberately delete a page. 6186** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6187** false will always have the "discard" flag set to true. 6188** ^Hence, a cache created with bPurgeable false will 6189** never contain any unpinned pages. 6190** 6191** [[the xCachesize() page cache method]] 6192** ^(The xCachesize() method may be called at any time by SQLite to set the 6193** suggested maximum cache-size (number of pages stored by) the cache 6194** instance passed as the first argument. This is the value configured using 6195** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6196** parameter, the implementation is not required to do anything with this 6197** value; it is advisory only. 6198** 6199** [[the xPagecount() page cache methods]] 6200** The xPagecount() method must return the number of pages currently 6201** stored in the cache, both pinned and unpinned. 6202** 6203** [[the xFetch() page cache methods]] 6204** The xFetch() method locates a page in the cache and returns a pointer to 6205** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6206** The pBuf element of the returned sqlite3_pcache_page object will be a 6207** pointer to a buffer of szPage bytes used to store the content of a 6208** single database page. The pExtra element of sqlite3_pcache_page will be 6209** a pointer to the szExtra bytes of extra storage that SQLite has requested 6210** for each entry in the page cache. 6211** 6212** The page to be fetched is determined by the key. ^The minimum key value 6213** is 1. After it has been retrieved using xFetch, the page is considered 6214** to be "pinned". 6215** 6216** If the requested page is already in the page cache, then the page cache 6217** implementation must return a pointer to the page buffer with its content 6218** intact. If the requested page is not already in the cache, then the 6219** cache implementation should use the value of the createFlag 6220** parameter to help it determined what action to take: 6221** 6222** <table border=1 width=85% align=center> 6223** <tr><th> createFlag <th> Behaviour when page is not already in cache 6224** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6225** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6226** Otherwise return NULL. 6227** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6228** NULL if allocating a new page is effectively impossible. 6229** </table> 6230** 6231** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6232** will only use a createFlag of 2 after a prior call with a createFlag of 1 6233** failed.)^ In between the to xFetch() calls, SQLite may 6234** attempt to unpin one or more cache pages by spilling the content of 6235** pinned pages to disk and synching the operating system disk cache. 6236** 6237** [[the xUnpin() page cache method]] 6238** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6239** as its second argument. If the third parameter, discard, is non-zero, 6240** then the page must be evicted from the cache. 6241** ^If the discard parameter is 6242** zero, then the page may be discarded or retained at the discretion of 6243** page cache implementation. ^The page cache implementation 6244** may choose to evict unpinned pages at any time. 6245** 6246** The cache must not perform any reference counting. A single 6247** call to xUnpin() unpins the page regardless of the number of prior calls 6248** to xFetch(). 6249** 6250** [[the xRekey() page cache methods]] 6251** The xRekey() method is used to change the key value associated with the 6252** page passed as the second argument. If the cache 6253** previously contains an entry associated with newKey, it must be 6254** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6255** to be pinned. 6256** 6257** When SQLite calls the xTruncate() method, the cache must discard all 6258** existing cache entries with page numbers (keys) greater than or equal 6259** to the value of the iLimit parameter passed to xTruncate(). If any 6260** of these pages are pinned, they are implicitly unpinned, meaning that 6261** they can be safely discarded. 6262** 6263** [[the xDestroy() page cache method]] 6264** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6265** All resources associated with the specified cache should be freed. ^After 6266** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6267** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6268** functions. 6269** 6270** [[the xShrink() page cache method]] 6271** ^SQLite invokes the xShrink() method when it wants the page cache to 6272** free up as much of heap memory as possible. The page cache implementation 6273** is not obligated to free any memory, but well-behaved implementations should 6274** do their best. 6275*/ 6276typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6277struct sqlite3_pcache_methods2 { 6278 int iVersion; 6279 void *pArg; 6280 int (*xInit)(void*); 6281 void (*xShutdown)(void*); 6282 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6283 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6284 int (*xPagecount)(sqlite3_pcache*); 6285 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6286 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6287 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6288 unsigned oldKey, unsigned newKey); 6289 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6290 void (*xDestroy)(sqlite3_pcache*); 6291 void (*xShrink)(sqlite3_pcache*); 6292}; 6293 6294/* 6295** This is the obsolete pcache_methods object that has now been replaced 6296** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6297** retained in the header file for backwards compatibility only. 6298*/ 6299typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6300struct sqlite3_pcache_methods { 6301 void *pArg; 6302 int (*xInit)(void*); 6303 void (*xShutdown)(void*); 6304 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6305 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6306 int (*xPagecount)(sqlite3_pcache*); 6307 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6308 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6309 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6310 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6311 void (*xDestroy)(sqlite3_pcache*); 6312}; 6313 6314 6315/* 6316** CAPI3REF: Online Backup Object 6317** 6318** The sqlite3_backup object records state information about an ongoing 6319** online backup operation. ^The sqlite3_backup object is created by 6320** a call to [sqlite3_backup_init()] and is destroyed by a call to 6321** [sqlite3_backup_finish()]. 6322** 6323** See Also: [Using the SQLite Online Backup API] 6324*/ 6325typedef struct sqlite3_backup sqlite3_backup; 6326 6327/* 6328** CAPI3REF: Online Backup API. 6329** 6330** The backup API copies the content of one database into another. 6331** It is useful either for creating backups of databases or 6332** for copying in-memory databases to or from persistent files. 6333** 6334** See Also: [Using the SQLite Online Backup API] 6335** 6336** ^SQLite holds a write transaction open on the destination database file 6337** for the duration of the backup operation. 6338** ^The source database is read-locked only while it is being read; 6339** it is not locked continuously for the entire backup operation. 6340** ^Thus, the backup may be performed on a live source database without 6341** preventing other database connections from 6342** reading or writing to the source database while the backup is underway. 6343** 6344** ^(To perform a backup operation: 6345** <ol> 6346** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6347** backup, 6348** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6349** the data between the two databases, and finally 6350** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6351** associated with the backup operation. 6352** </ol>)^ 6353** There should be exactly one call to sqlite3_backup_finish() for each 6354** successful call to sqlite3_backup_init(). 6355** 6356** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6357** 6358** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6359** [database connection] associated with the destination database 6360** and the database name, respectively. 6361** ^The database name is "main" for the main database, "temp" for the 6362** temporary database, or the name specified after the AS keyword in 6363** an [ATTACH] statement for an attached database. 6364** ^The S and M arguments passed to 6365** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6366** and database name of the source database, respectively. 6367** ^The source and destination [database connections] (parameters S and D) 6368** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6369** an error. 6370** 6371** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6372** returned and an error code and error message are stored in the 6373** destination [database connection] D. 6374** ^The error code and message for the failed call to sqlite3_backup_init() 6375** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6376** [sqlite3_errmsg16()] functions. 6377** ^A successful call to sqlite3_backup_init() returns a pointer to an 6378** [sqlite3_backup] object. 6379** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6380** sqlite3_backup_finish() functions to perform the specified backup 6381** operation. 6382** 6383** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6384** 6385** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6386** the source and destination databases specified by [sqlite3_backup] object B. 6387** ^If N is negative, all remaining source pages are copied. 6388** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6389** are still more pages to be copied, then the function returns [SQLITE_OK]. 6390** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6391** from source to destination, then it returns [SQLITE_DONE]. 6392** ^If an error occurs while running sqlite3_backup_step(B,N), 6393** then an [error code] is returned. ^As well as [SQLITE_OK] and 6394** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6395** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6396** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6397** 6398** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6399** <ol> 6400** <li> the destination database was opened read-only, or 6401** <li> the destination database is using write-ahead-log journaling 6402** and the destination and source page sizes differ, or 6403** <li> the destination database is an in-memory database and the 6404** destination and source page sizes differ. 6405** </ol>)^ 6406** 6407** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6408** the [sqlite3_busy_handler | busy-handler function] 6409** is invoked (if one is specified). ^If the 6410** busy-handler returns non-zero before the lock is available, then 6411** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6412** sqlite3_backup_step() can be retried later. ^If the source 6413** [database connection] 6414** is being used to write to the source database when sqlite3_backup_step() 6415** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6416** case the call to sqlite3_backup_step() can be retried later on. ^(If 6417** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6418** [SQLITE_READONLY] is returned, then 6419** there is no point in retrying the call to sqlite3_backup_step(). These 6420** errors are considered fatal.)^ The application must accept 6421** that the backup operation has failed and pass the backup operation handle 6422** to the sqlite3_backup_finish() to release associated resources. 6423** 6424** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6425** on the destination file. ^The exclusive lock is not released until either 6426** sqlite3_backup_finish() is called or the backup operation is complete 6427** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6428** sqlite3_backup_step() obtains a [shared lock] on the source database that 6429** lasts for the duration of the sqlite3_backup_step() call. 6430** ^Because the source database is not locked between calls to 6431** sqlite3_backup_step(), the source database may be modified mid-way 6432** through the backup process. ^If the source database is modified by an 6433** external process or via a database connection other than the one being 6434** used by the backup operation, then the backup will be automatically 6435** restarted by the next call to sqlite3_backup_step(). ^If the source 6436** database is modified by the using the same database connection as is used 6437** by the backup operation, then the backup database is automatically 6438** updated at the same time. 6439** 6440** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6441** 6442** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6443** application wishes to abandon the backup operation, the application 6444** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6445** ^The sqlite3_backup_finish() interfaces releases all 6446** resources associated with the [sqlite3_backup] object. 6447** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6448** active write-transaction on the destination database is rolled back. 6449** The [sqlite3_backup] object is invalid 6450** and may not be used following a call to sqlite3_backup_finish(). 6451** 6452** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6453** sqlite3_backup_step() errors occurred, regardless or whether or not 6454** sqlite3_backup_step() completed. 6455** ^If an out-of-memory condition or IO error occurred during any prior 6456** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6457** sqlite3_backup_finish() returns the corresponding [error code]. 6458** 6459** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6460** is not a permanent error and does not affect the return value of 6461** sqlite3_backup_finish(). 6462** 6463** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6464** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6465** 6466** ^Each call to sqlite3_backup_step() sets two values inside 6467** the [sqlite3_backup] object: the number of pages still to be backed 6468** up and the total number of pages in the source database file. 6469** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6470** retrieve these two values, respectively. 6471** 6472** ^The values returned by these functions are only updated by 6473** sqlite3_backup_step(). ^If the source database is modified during a backup 6474** operation, then the values are not updated to account for any extra 6475** pages that need to be updated or the size of the source database file 6476** changing. 6477** 6478** <b>Concurrent Usage of Database Handles</b> 6479** 6480** ^The source [database connection] may be used by the application for other 6481** purposes while a backup operation is underway or being initialized. 6482** ^If SQLite is compiled and configured to support threadsafe database 6483** connections, then the source database connection may be used concurrently 6484** from within other threads. 6485** 6486** However, the application must guarantee that the destination 6487** [database connection] is not passed to any other API (by any thread) after 6488** sqlite3_backup_init() is called and before the corresponding call to 6489** sqlite3_backup_finish(). SQLite does not currently check to see 6490** if the application incorrectly accesses the destination [database connection] 6491** and so no error code is reported, but the operations may malfunction 6492** nevertheless. Use of the destination database connection while a 6493** backup is in progress might also also cause a mutex deadlock. 6494** 6495** If running in [shared cache mode], the application must 6496** guarantee that the shared cache used by the destination database 6497** is not accessed while the backup is running. In practice this means 6498** that the application must guarantee that the disk file being 6499** backed up to is not accessed by any connection within the process, 6500** not just the specific connection that was passed to sqlite3_backup_init(). 6501** 6502** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6503** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6504** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6505** APIs are not strictly speaking threadsafe. If they are invoked at the 6506** same time as another thread is invoking sqlite3_backup_step() it is 6507** possible that they return invalid values. 6508*/ 6509sqlite3_backup *sqlite3_backup_init( 6510 sqlite3 *pDest, /* Destination database handle */ 6511 const char *zDestName, /* Destination database name */ 6512 sqlite3 *pSource, /* Source database handle */ 6513 const char *zSourceName /* Source database name */ 6514); 6515int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6516int sqlite3_backup_finish(sqlite3_backup *p); 6517int sqlite3_backup_remaining(sqlite3_backup *p); 6518int sqlite3_backup_pagecount(sqlite3_backup *p); 6519 6520/* 6521** CAPI3REF: Unlock Notification 6522** 6523** ^When running in shared-cache mode, a database operation may fail with 6524** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6525** individual tables within the shared-cache cannot be obtained. See 6526** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6527** ^This API may be used to register a callback that SQLite will invoke 6528** when the connection currently holding the required lock relinquishes it. 6529** ^This API is only available if the library was compiled with the 6530** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6531** 6532** See Also: [Using the SQLite Unlock Notification Feature]. 6533** 6534** ^Shared-cache locks are released when a database connection concludes 6535** its current transaction, either by committing it or rolling it back. 6536** 6537** ^When a connection (known as the blocked connection) fails to obtain a 6538** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6539** identity of the database connection (the blocking connection) that 6540** has locked the required resource is stored internally. ^After an 6541** application receives an SQLITE_LOCKED error, it may call the 6542** sqlite3_unlock_notify() method with the blocked connection handle as 6543** the first argument to register for a callback that will be invoked 6544** when the blocking connections current transaction is concluded. ^The 6545** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6546** call that concludes the blocking connections transaction. 6547** 6548** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6549** there is a chance that the blocking connection will have already 6550** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6551** If this happens, then the specified callback is invoked immediately, 6552** from within the call to sqlite3_unlock_notify().)^ 6553** 6554** ^If the blocked connection is attempting to obtain a write-lock on a 6555** shared-cache table, and more than one other connection currently holds 6556** a read-lock on the same table, then SQLite arbitrarily selects one of 6557** the other connections to use as the blocking connection. 6558** 6559** ^(There may be at most one unlock-notify callback registered by a 6560** blocked connection. If sqlite3_unlock_notify() is called when the 6561** blocked connection already has a registered unlock-notify callback, 6562** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6563** called with a NULL pointer as its second argument, then any existing 6564** unlock-notify callback is canceled. ^The blocked connections 6565** unlock-notify callback may also be canceled by closing the blocked 6566** connection using [sqlite3_close()]. 6567** 6568** The unlock-notify callback is not reentrant. If an application invokes 6569** any sqlite3_xxx API functions from within an unlock-notify callback, a 6570** crash or deadlock may be the result. 6571** 6572** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6573** returns SQLITE_OK. 6574** 6575** <b>Callback Invocation Details</b> 6576** 6577** When an unlock-notify callback is registered, the application provides a 6578** single void* pointer that is passed to the callback when it is invoked. 6579** However, the signature of the callback function allows SQLite to pass 6580** it an array of void* context pointers. The first argument passed to 6581** an unlock-notify callback is a pointer to an array of void* pointers, 6582** and the second is the number of entries in the array. 6583** 6584** When a blocking connections transaction is concluded, there may be 6585** more than one blocked connection that has registered for an unlock-notify 6586** callback. ^If two or more such blocked connections have specified the 6587** same callback function, then instead of invoking the callback function 6588** multiple times, it is invoked once with the set of void* context pointers 6589** specified by the blocked connections bundled together into an array. 6590** This gives the application an opportunity to prioritize any actions 6591** related to the set of unblocked database connections. 6592** 6593** <b>Deadlock Detection</b> 6594** 6595** Assuming that after registering for an unlock-notify callback a 6596** database waits for the callback to be issued before taking any further 6597** action (a reasonable assumption), then using this API may cause the 6598** application to deadlock. For example, if connection X is waiting for 6599** connection Y's transaction to be concluded, and similarly connection 6600** Y is waiting on connection X's transaction, then neither connection 6601** will proceed and the system may remain deadlocked indefinitely. 6602** 6603** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6604** detection. ^If a given call to sqlite3_unlock_notify() would put the 6605** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6606** unlock-notify callback is registered. The system is said to be in 6607** a deadlocked state if connection A has registered for an unlock-notify 6608** callback on the conclusion of connection B's transaction, and connection 6609** B has itself registered for an unlock-notify callback when connection 6610** A's transaction is concluded. ^Indirect deadlock is also detected, so 6611** the system is also considered to be deadlocked if connection B has 6612** registered for an unlock-notify callback on the conclusion of connection 6613** C's transaction, where connection C is waiting on connection A. ^Any 6614** number of levels of indirection are allowed. 6615** 6616** <b>The "DROP TABLE" Exception</b> 6617** 6618** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6619** always appropriate to call sqlite3_unlock_notify(). There is however, 6620** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6621** SQLite checks if there are any currently executing SELECT statements 6622** that belong to the same connection. If there are, SQLITE_LOCKED is 6623** returned. In this case there is no "blocking connection", so invoking 6624** sqlite3_unlock_notify() results in the unlock-notify callback being 6625** invoked immediately. If the application then re-attempts the "DROP TABLE" 6626** or "DROP INDEX" query, an infinite loop might be the result. 6627** 6628** One way around this problem is to check the extended error code returned 6629** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6630** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6631** the special "DROP TABLE/INDEX" case, the extended error code is just 6632** SQLITE_LOCKED.)^ 6633*/ 6634int sqlite3_unlock_notify( 6635 sqlite3 *pBlocked, /* Waiting connection */ 6636 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6637 void *pNotifyArg /* Argument to pass to xNotify */ 6638); 6639 6640 6641/* 6642** CAPI3REF: String Comparison 6643** 6644** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 6645** and extensions to compare the contents of two buffers containing UTF-8 6646** strings in a case-independent fashion, using the same definition of "case 6647** independence" that SQLite uses internally when comparing identifiers. 6648*/ 6649int sqlite3_stricmp(const char *, const char *); 6650int sqlite3_strnicmp(const char *, const char *, int); 6651 6652/* 6653** CAPI3REF: Error Logging Interface 6654** 6655** ^The [sqlite3_log()] interface writes a message into the error log 6656** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6657** ^If logging is enabled, the zFormat string and subsequent arguments are 6658** used with [sqlite3_snprintf()] to generate the final output string. 6659** 6660** The sqlite3_log() interface is intended for use by extensions such as 6661** virtual tables, collating functions, and SQL functions. While there is 6662** nothing to prevent an application from calling sqlite3_log(), doing so 6663** is considered bad form. 6664** 6665** The zFormat string must not be NULL. 6666** 6667** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6668** will not use dynamically allocated memory. The log message is stored in 6669** a fixed-length buffer on the stack. If the log message is longer than 6670** a few hundred characters, it will be truncated to the length of the 6671** buffer. 6672*/ 6673void sqlite3_log(int iErrCode, const char *zFormat, ...); 6674 6675/* 6676** CAPI3REF: Write-Ahead Log Commit Hook 6677** 6678** ^The [sqlite3_wal_hook()] function is used to register a callback that 6679** will be invoked each time a database connection commits data to a 6680** [write-ahead log] (i.e. whenever a transaction is committed in 6681** [journal_mode | journal_mode=WAL mode]). 6682** 6683** ^The callback is invoked by SQLite after the commit has taken place and 6684** the associated write-lock on the database released, so the implementation 6685** may read, write or [checkpoint] the database as required. 6686** 6687** ^The first parameter passed to the callback function when it is invoked 6688** is a copy of the third parameter passed to sqlite3_wal_hook() when 6689** registering the callback. ^The second is a copy of the database handle. 6690** ^The third parameter is the name of the database that was written to - 6691** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6692** is the number of pages currently in the write-ahead log file, 6693** including those that were just committed. 6694** 6695** The callback function should normally return [SQLITE_OK]. ^If an error 6696** code is returned, that error will propagate back up through the 6697** SQLite code base to cause the statement that provoked the callback 6698** to report an error, though the commit will have still occurred. If the 6699** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6700** that does not correspond to any valid SQLite error code, the results 6701** are undefined. 6702** 6703** A single database handle may have at most a single write-ahead log callback 6704** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6705** previously registered write-ahead log callback. ^Note that the 6706** [sqlite3_wal_autocheckpoint()] interface and the 6707** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6708** those overwrite any prior [sqlite3_wal_hook()] settings. 6709*/ 6710void *sqlite3_wal_hook( 6711 sqlite3*, 6712 int(*)(void *,sqlite3*,const char*,int), 6713 void* 6714); 6715 6716/* 6717** CAPI3REF: Configure an auto-checkpoint 6718** 6719** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6720** [sqlite3_wal_hook()] that causes any database on [database connection] D 6721** to automatically [checkpoint] 6722** after committing a transaction if there are N or 6723** more frames in the [write-ahead log] file. ^Passing zero or 6724** a negative value as the nFrame parameter disables automatic 6725** checkpoints entirely. 6726** 6727** ^The callback registered by this function replaces any existing callback 6728** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6729** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6730** configured by this function. 6731** 6732** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6733** from SQL. 6734** 6735** ^Every new [database connection] defaults to having the auto-checkpoint 6736** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6737** pages. The use of this interface 6738** is only necessary if the default setting is found to be suboptimal 6739** for a particular application. 6740*/ 6741int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6742 6743/* 6744** CAPI3REF: Checkpoint a database 6745** 6746** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6747** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6748** empty string, then a checkpoint is run on all databases of 6749** connection D. ^If the database connection D is not in 6750** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6751** 6752** ^The [wal_checkpoint pragma] can be used to invoke this interface 6753** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6754** [wal_autocheckpoint pragma] can be used to cause this interface to be 6755** run whenever the WAL reaches a certain size threshold. 6756** 6757** See also: [sqlite3_wal_checkpoint_v2()] 6758*/ 6759int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6760 6761/* 6762** CAPI3REF: Checkpoint a database 6763** 6764** Run a checkpoint operation on WAL database zDb attached to database 6765** handle db. The specific operation is determined by the value of the 6766** eMode parameter: 6767** 6768** <dl> 6769** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 6770** Checkpoint as many frames as possible without waiting for any database 6771** readers or writers to finish. Sync the db file if all frames in the log 6772** are checkpointed. This mode is the same as calling 6773** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 6774** 6775** <dt>SQLITE_CHECKPOINT_FULL<dd> 6776** This mode blocks (calls the busy-handler callback) until there is no 6777** database writer and all readers are reading from the most recent database 6778** snapshot. It then checkpoints all frames in the log file and syncs the 6779** database file. This call blocks database writers while it is running, 6780** but not database readers. 6781** 6782** <dt>SQLITE_CHECKPOINT_RESTART<dd> 6783** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 6784** checkpointing the log file it blocks (calls the busy-handler callback) 6785** until all readers are reading from the database file only. This ensures 6786** that the next client to write to the database file restarts the log file 6787** from the beginning. This call blocks database writers while it is running, 6788** but not database readers. 6789** </dl> 6790** 6791** If pnLog is not NULL, then *pnLog is set to the total number of frames in 6792** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 6793** the total number of checkpointed frames (including any that were already 6794** checkpointed when this function is called). *pnLog and *pnCkpt may be 6795** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 6796** If no values are available because of an error, they are both set to -1 6797** before returning to communicate this to the caller. 6798** 6799** All calls obtain an exclusive "checkpoint" lock on the database file. If 6800** any other process is running a checkpoint operation at the same time, the 6801** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 6802** busy-handler configured, it will not be invoked in this case. 6803** 6804** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 6805** "writer" lock on the database file. If the writer lock cannot be obtained 6806** immediately, and a busy-handler is configured, it is invoked and the writer 6807** lock retried until either the busy-handler returns 0 or the lock is 6808** successfully obtained. The busy-handler is also invoked while waiting for 6809** database readers as described above. If the busy-handler returns 0 before 6810** the writer lock is obtained or while waiting for database readers, the 6811** checkpoint operation proceeds from that point in the same way as 6812** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 6813** without blocking any further. SQLITE_BUSY is returned in this case. 6814** 6815** If parameter zDb is NULL or points to a zero length string, then the 6816** specified operation is attempted on all WAL databases. In this case the 6817** values written to output parameters *pnLog and *pnCkpt are undefined. If 6818** an SQLITE_BUSY error is encountered when processing one or more of the 6819** attached WAL databases, the operation is still attempted on any remaining 6820** attached databases and SQLITE_BUSY is returned to the caller. If any other 6821** error occurs while processing an attached database, processing is abandoned 6822** and the error code returned to the caller immediately. If no error 6823** (SQLITE_BUSY or otherwise) is encountered while processing the attached 6824** databases, SQLITE_OK is returned. 6825** 6826** If database zDb is the name of an attached database that is not in WAL 6827** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 6828** zDb is not NULL (or a zero length string) and is not the name of any 6829** attached database, SQLITE_ERROR is returned to the caller. 6830*/ 6831int sqlite3_wal_checkpoint_v2( 6832 sqlite3 *db, /* Database handle */ 6833 const char *zDb, /* Name of attached database (or NULL) */ 6834 int eMode, /* SQLITE_CHECKPOINT_* value */ 6835 int *pnLog, /* OUT: Size of WAL log in frames */ 6836 int *pnCkpt /* OUT: Total number of frames checkpointed */ 6837); 6838 6839/* 6840** CAPI3REF: Checkpoint operation parameters 6841** 6842** These constants can be used as the 3rd parameter to 6843** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 6844** documentation for additional information about the meaning and use of 6845** each of these values. 6846*/ 6847#define SQLITE_CHECKPOINT_PASSIVE 0 6848#define SQLITE_CHECKPOINT_FULL 1 6849#define SQLITE_CHECKPOINT_RESTART 2 6850 6851/* 6852** CAPI3REF: Virtual Table Interface Configuration 6853** 6854** This function may be called by either the [xConnect] or [xCreate] method 6855** of a [virtual table] implementation to configure 6856** various facets of the virtual table interface. 6857** 6858** If this interface is invoked outside the context of an xConnect or 6859** xCreate virtual table method then the behavior is undefined. 6860** 6861** At present, there is only one option that may be configured using 6862** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 6863** may be added in the future. 6864*/ 6865int sqlite3_vtab_config(sqlite3*, int op, ...); 6866 6867/* 6868** CAPI3REF: Virtual Table Configuration Options 6869** 6870** These macros define the various options to the 6871** [sqlite3_vtab_config()] interface that [virtual table] implementations 6872** can use to customize and optimize their behavior. 6873** 6874** <dl> 6875** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 6876** <dd>Calls of the form 6877** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 6878** where X is an integer. If X is zero, then the [virtual table] whose 6879** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 6880** support constraints. In this configuration (which is the default) if 6881** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 6882** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 6883** specified as part of the users SQL statement, regardless of the actual 6884** ON CONFLICT mode specified. 6885** 6886** If X is non-zero, then the virtual table implementation guarantees 6887** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 6888** any modifications to internal or persistent data structures have been made. 6889** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 6890** is able to roll back a statement or database transaction, and abandon 6891** or continue processing the current SQL statement as appropriate. 6892** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 6893** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 6894** had been ABORT. 6895** 6896** Virtual table implementations that are required to handle OR REPLACE 6897** must do so within the [xUpdate] method. If a call to the 6898** [sqlite3_vtab_on_conflict()] function indicates that the current ON 6899** CONFLICT policy is REPLACE, the virtual table implementation should 6900** silently replace the appropriate rows within the xUpdate callback and 6901** return SQLITE_OK. Or, if this is not possible, it may return 6902** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 6903** constraint handling. 6904** </dl> 6905*/ 6906#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 6907 6908/* 6909** CAPI3REF: Determine The Virtual Table Conflict Policy 6910** 6911** This function may only be called from within a call to the [xUpdate] method 6912** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 6913** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 6914** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 6915** of the SQL statement that triggered the call to the [xUpdate] method of the 6916** [virtual table]. 6917*/ 6918int sqlite3_vtab_on_conflict(sqlite3 *); 6919 6920/* 6921** CAPI3REF: Conflict resolution modes 6922** 6923** These constants are returned by [sqlite3_vtab_on_conflict()] to 6924** inform a [virtual table] implementation what the [ON CONFLICT] mode 6925** is for the SQL statement being evaluated. 6926** 6927** Note that the [SQLITE_IGNORE] constant is also used as a potential 6928** return value from the [sqlite3_set_authorizer()] callback and that 6929** [SQLITE_ABORT] is also a [result code]. 6930*/ 6931#define SQLITE_ROLLBACK 1 6932/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 6933#define SQLITE_FAIL 3 6934/* #define SQLITE_ABORT 4 // Also an error code */ 6935#define SQLITE_REPLACE 5 6936 6937 6938 6939/* 6940** Undo the hack that converts floating point types to integer for 6941** builds on processors without floating point support. 6942*/ 6943#ifdef SQLITE_OMIT_FLOATING_POINT 6944# undef double 6945#endif 6946 6947#ifdef __cplusplus 6948} /* End of the 'extern "C"' block */ 6949#endif 6950#endif 6951