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_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 457#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 458#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 459#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 460 461/* 462** CAPI3REF: Flags For File Open Operations 463** 464** These bit values are intended for use in the 465** 3rd parameter to the [sqlite3_open_v2()] interface and 466** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 467*/ 468#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 469#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 470#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 471#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 472#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 473#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 474#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 475#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 476#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 477#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 478#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 479#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 480#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 481#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 482#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 483#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 484#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 485#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 486#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 487 488/* Reserved: 0x00F00000 */ 489 490/* 491** CAPI3REF: Device Characteristics 492** 493** The xDeviceCharacteristics method of the [sqlite3_io_methods] 494** object returns an integer which is a vector of the these 495** bit values expressing I/O characteristics of the mass storage 496** device that holds the file that the [sqlite3_io_methods] 497** refers to. 498** 499** The SQLITE_IOCAP_ATOMIC property means that all writes of 500** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 501** mean that writes of blocks that are nnn bytes in size and 502** are aligned to an address which is an integer multiple of 503** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 504** that when data is appended to a file, the data is appended 505** first then the size of the file is extended, never the other 506** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 507** information is written to disk in the same order as calls 508** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 509** after reboot following a crash or power loss, the only bytes in a 510** file that were written at the application level might have changed 511** and that adjacent bytes, even bytes within the same sector are 512** guaranteed to be unchanged. 513*/ 514#define SQLITE_IOCAP_ATOMIC 0x00000001 515#define SQLITE_IOCAP_ATOMIC512 0x00000002 516#define SQLITE_IOCAP_ATOMIC1K 0x00000004 517#define SQLITE_IOCAP_ATOMIC2K 0x00000008 518#define SQLITE_IOCAP_ATOMIC4K 0x00000010 519#define SQLITE_IOCAP_ATOMIC8K 0x00000020 520#define SQLITE_IOCAP_ATOMIC16K 0x00000040 521#define SQLITE_IOCAP_ATOMIC32K 0x00000080 522#define SQLITE_IOCAP_ATOMIC64K 0x00000100 523#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 524#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 525#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 526#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 527 528/* 529** CAPI3REF: File Locking Levels 530** 531** SQLite uses one of these integer values as the second 532** argument to calls it makes to the xLock() and xUnlock() methods 533** of an [sqlite3_io_methods] object. 534*/ 535#define SQLITE_LOCK_NONE 0 536#define SQLITE_LOCK_SHARED 1 537#define SQLITE_LOCK_RESERVED 2 538#define SQLITE_LOCK_PENDING 3 539#define SQLITE_LOCK_EXCLUSIVE 4 540 541/* 542** CAPI3REF: Synchronization Type Flags 543** 544** When SQLite invokes the xSync() method of an 545** [sqlite3_io_methods] object it uses a combination of 546** these integer values as the second argument. 547** 548** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 549** sync operation only needs to flush data to mass storage. Inode 550** information need not be flushed. If the lower four bits of the flag 551** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 552** If the lower four bits equal SQLITE_SYNC_FULL, that means 553** to use Mac OS X style fullsync instead of fsync(). 554** 555** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 556** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 557** settings. The [synchronous pragma] determines when calls to the 558** xSync VFS method occur and applies uniformly across all platforms. 559** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 560** energetic or rigorous or forceful the sync operations are and 561** only make a difference on Mac OSX for the default SQLite code. 562** (Third-party VFS implementations might also make the distinction 563** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 564** operating systems natively supported by SQLite, only Mac OSX 565** cares about the difference.) 566*/ 567#define SQLITE_SYNC_NORMAL 0x00002 568#define SQLITE_SYNC_FULL 0x00003 569#define SQLITE_SYNC_DATAONLY 0x00010 570 571/* 572** CAPI3REF: OS Interface Open File Handle 573** 574** An [sqlite3_file] object represents an open file in the 575** [sqlite3_vfs | OS interface layer]. Individual OS interface 576** implementations will 577** want to subclass this object by appending additional fields 578** for their own use. The pMethods entry is a pointer to an 579** [sqlite3_io_methods] object that defines methods for performing 580** I/O operations on the open file. 581*/ 582typedef struct sqlite3_file sqlite3_file; 583struct sqlite3_file { 584 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 585}; 586 587/* 588** CAPI3REF: OS Interface File Virtual Methods Object 589** 590** Every file opened by the [sqlite3_vfs.xOpen] method populates an 591** [sqlite3_file] object (or, more commonly, a subclass of the 592** [sqlite3_file] object) with a pointer to an instance of this object. 593** This object defines the methods used to perform various operations 594** against the open file represented by the [sqlite3_file] object. 595** 596** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 597** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 598** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 599** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 600** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 601** to NULL. 602** 603** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 604** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 605** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 606** flag may be ORed in to indicate that only the data of the file 607** and not its inode needs to be synced. 608** 609** The integer values to xLock() and xUnlock() are one of 610** <ul> 611** <li> [SQLITE_LOCK_NONE], 612** <li> [SQLITE_LOCK_SHARED], 613** <li> [SQLITE_LOCK_RESERVED], 614** <li> [SQLITE_LOCK_PENDING], or 615** <li> [SQLITE_LOCK_EXCLUSIVE]. 616** </ul> 617** xLock() increases the lock. xUnlock() decreases the lock. 618** The xCheckReservedLock() method checks whether any database connection, 619** either in this process or in some other process, is holding a RESERVED, 620** PENDING, or EXCLUSIVE lock on the file. It returns true 621** if such a lock exists and false otherwise. 622** 623** The xFileControl() method is a generic interface that allows custom 624** VFS implementations to directly control an open file using the 625** [sqlite3_file_control()] interface. The second "op" argument is an 626** integer opcode. The third argument is a generic pointer intended to 627** point to a structure that may contain arguments or space in which to 628** write return values. Potential uses for xFileControl() might be 629** functions to enable blocking locks with timeouts, to change the 630** locking strategy (for example to use dot-file locks), to inquire 631** about the status of a lock, or to break stale locks. The SQLite 632** core reserves all opcodes less than 100 for its own use. 633** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 634** Applications that define a custom xFileControl method should use opcodes 635** greater than 100 to avoid conflicts. VFS implementations should 636** return [SQLITE_NOTFOUND] for file control opcodes that they do not 637** recognize. 638** 639** The xSectorSize() method returns the sector size of the 640** device that underlies the file. The sector size is the 641** minimum write that can be performed without disturbing 642** other bytes in the file. The xDeviceCharacteristics() 643** method returns a bit vector describing behaviors of the 644** underlying device: 645** 646** <ul> 647** <li> [SQLITE_IOCAP_ATOMIC] 648** <li> [SQLITE_IOCAP_ATOMIC512] 649** <li> [SQLITE_IOCAP_ATOMIC1K] 650** <li> [SQLITE_IOCAP_ATOMIC2K] 651** <li> [SQLITE_IOCAP_ATOMIC4K] 652** <li> [SQLITE_IOCAP_ATOMIC8K] 653** <li> [SQLITE_IOCAP_ATOMIC16K] 654** <li> [SQLITE_IOCAP_ATOMIC32K] 655** <li> [SQLITE_IOCAP_ATOMIC64K] 656** <li> [SQLITE_IOCAP_SAFE_APPEND] 657** <li> [SQLITE_IOCAP_SEQUENTIAL] 658** </ul> 659** 660** The SQLITE_IOCAP_ATOMIC property means that all writes of 661** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 662** mean that writes of blocks that are nnn bytes in size and 663** are aligned to an address which is an integer multiple of 664** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 665** that when data is appended to a file, the data is appended 666** first then the size of the file is extended, never the other 667** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 668** information is written to disk in the same order as calls 669** to xWrite(). 670** 671** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 672** in the unread portions of the buffer with zeros. A VFS that 673** fails to zero-fill short reads might seem to work. However, 674** failure to zero-fill short reads will eventually lead to 675** database corruption. 676*/ 677typedef struct sqlite3_io_methods sqlite3_io_methods; 678struct sqlite3_io_methods { 679 int iVersion; 680 int (*xClose)(sqlite3_file*); 681 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 682 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 683 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 684 int (*xSync)(sqlite3_file*, int flags); 685 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 686 int (*xLock)(sqlite3_file*, int); 687 int (*xUnlock)(sqlite3_file*, int); 688 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 689 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 690 int (*xSectorSize)(sqlite3_file*); 691 int (*xDeviceCharacteristics)(sqlite3_file*); 692 /* Methods above are valid for version 1 */ 693 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 694 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 695 void (*xShmBarrier)(sqlite3_file*); 696 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 697 /* Methods above are valid for version 2 */ 698 /* Additional methods may be added in future releases */ 699}; 700 701/* 702** CAPI3REF: Standard File Control Opcodes 703** 704** These integer constants are opcodes for the xFileControl method 705** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 706** interface. 707** 708** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 709** opcode causes the xFileControl method to write the current state of 710** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 711** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 712** into an integer that the pArg argument points to. This capability 713** is used during testing and only needs to be supported when SQLITE_TEST 714** is defined. 715** <ul> 716** <li>[[SQLITE_FCNTL_SIZE_HINT]] 717** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 718** layer a hint of how large the database file will grow to be during the 719** current transaction. This hint is not guaranteed to be accurate but it 720** is often close. The underlying VFS might choose to preallocate database 721** file space based on this hint in order to help writes to the database 722** file run faster. 723** 724** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 725** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 726** extends and truncates the database file in chunks of a size specified 727** by the user. The fourth argument to [sqlite3_file_control()] should 728** point to an integer (type int) containing the new chunk-size to use 729** for the nominated database. Allocating database file space in large 730** chunks (say 1MB at a time), may reduce file-system fragmentation and 731** improve performance on some systems. 732** 733** <li>[[SQLITE_FCNTL_FILE_POINTER]] 734** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 735** to the [sqlite3_file] object associated with a particular database 736** connection. See the [sqlite3_file_control()] documentation for 737** additional information. 738** 739** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 740** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by 741** SQLite and sent to all VFSes in place of a call to the xSync method 742** when the database connection has [PRAGMA synchronous] set to OFF.)^ 743** Some specialized VFSes need this signal in order to operate correctly 744** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 745** VFSes do not need this signal and should silently ignore this opcode. 746** Applications should not call [sqlite3_file_control()] with this 747** opcode as doing so may disrupt the operation of the specialized VFSes 748** that do require it. 749** 750** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 751** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 752** retry counts and intervals for certain disk I/O operations for the 753** windows [VFS] in order to provide robustness in the presence of 754** anti-virus programs. By default, the windows VFS will retry file read, 755** file write, and file delete operations up to 10 times, with a delay 756** of 25 milliseconds before the first retry and with the delay increasing 757** by an additional 25 milliseconds with each subsequent retry. This 758** opcode allows these two values (10 retries and 25 milliseconds of delay) 759** to be adjusted. The values are changed for all database connections 760** within the same process. The argument is a pointer to an array of two 761** integers where the first integer i the new retry count and the second 762** integer is the delay. If either integer is negative, then the setting 763** is not changed but instead the prior value of that setting is written 764** into the array entry, allowing the current retry settings to be 765** interrogated. The zDbName parameter is ignored. 766** 767** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 768** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 769** persistent [WAL | Write AHead Log] setting. By default, the auxiliary 770** write ahead log and shared memory files used for transaction control 771** are automatically deleted when the latest connection to the database 772** closes. Setting persistent WAL mode causes those files to persist after 773** close. Persisting the files is useful when other processes that do not 774** have write permission on the directory containing the database file want 775** to read the database file, as the WAL and shared memory files must exist 776** in order for the database to be readable. The fourth parameter to 777** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 778** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 779** WAL mode. If the integer is -1, then it is overwritten with the current 780** WAL persistence setting. 781** 782** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 783** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 784** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 785** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 786** xDeviceCharacteristics methods. The fourth parameter to 787** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 788** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 789** mode. If the integer is -1, then it is overwritten with the current 790** zero-damage mode setting. 791** 792** <li>[[SQLITE_FCNTL_OVERWRITE]] 793** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 794** a write transaction to indicate that, unless it is rolled back for some 795** reason, the entire database file will be overwritten by the current 796** transaction. This is used by VACUUM operations. 797** 798** <li>[[SQLITE_FCNTL_VFSNAME]] 799** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 800** all [VFSes] in the VFS stack. The names are of all VFS shims and the 801** final bottom-level VFS are written into memory obtained from 802** [sqlite3_malloc()] and the result is stored in the char* variable 803** that the fourth parameter of [sqlite3_file_control()] points to. 804** The caller is responsible for freeing the memory when done. As with 805** all file-control actions, there is no guarantee that this will actually 806** do anything. Callers should initialize the char* variable to a NULL 807** pointer in case this file-control is not implemented. This file-control 808** is intended for diagnostic use only. 809** 810** <li>[[SQLITE_FCNTL_PRAGMA]] 811** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 812** file control is sent to the open [sqlite3_file] object corresponding 813** to the database file to which the pragma statement refers. ^The argument 814** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 815** pointers to strings (char**) in which the second element of the array 816** is the name of the pragma and the third element is the argument to the 817** pragma or NULL if the pragma has no argument. ^The handler for an 818** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 819** of the char** argument point to a string obtained from [sqlite3_mprintf()] 820** or the equivalent and that string will become the result of the pragma or 821** the error message if the pragma fails. ^If the 822** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 823** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 824** file control returns [SQLITE_OK], then the parser assumes that the 825** VFS has handled the PRAGMA itself and the parser generates a no-op 826** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns 827** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 828** that the VFS encountered an error while handling the [PRAGMA] and the 829** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 830** file control occurs at the beginning of pragma statement analysis and so 831** it is able to override built-in [PRAGMA] statements. 832** </ul> 833*/ 834#define SQLITE_FCNTL_LOCKSTATE 1 835#define SQLITE_GET_LOCKPROXYFILE 2 836#define SQLITE_SET_LOCKPROXYFILE 3 837#define SQLITE_LAST_ERRNO 4 838#define SQLITE_FCNTL_SIZE_HINT 5 839#define SQLITE_FCNTL_CHUNK_SIZE 6 840#define SQLITE_FCNTL_FILE_POINTER 7 841#define SQLITE_FCNTL_SYNC_OMITTED 8 842#define SQLITE_FCNTL_WIN32_AV_RETRY 9 843#define SQLITE_FCNTL_PERSIST_WAL 10 844#define SQLITE_FCNTL_OVERWRITE 11 845#define SQLITE_FCNTL_VFSNAME 12 846#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 847#define SQLITE_FCNTL_PRAGMA 14 848 849/* 850** CAPI3REF: Mutex Handle 851** 852** The mutex module within SQLite defines [sqlite3_mutex] to be an 853** abstract type for a mutex object. The SQLite core never looks 854** at the internal representation of an [sqlite3_mutex]. It only 855** deals with pointers to the [sqlite3_mutex] object. 856** 857** Mutexes are created using [sqlite3_mutex_alloc()]. 858*/ 859typedef struct sqlite3_mutex sqlite3_mutex; 860 861/* 862** CAPI3REF: OS Interface Object 863** 864** An instance of the sqlite3_vfs object defines the interface between 865** the SQLite core and the underlying operating system. The "vfs" 866** in the name of the object stands for "virtual file system". See 867** the [VFS | VFS documentation] for further information. 868** 869** The value of the iVersion field is initially 1 but may be larger in 870** future versions of SQLite. Additional fields may be appended to this 871** object when the iVersion value is increased. Note that the structure 872** of the sqlite3_vfs object changes in the transaction between 873** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 874** modified. 875** 876** The szOsFile field is the size of the subclassed [sqlite3_file] 877** structure used by this VFS. mxPathname is the maximum length of 878** a pathname in this VFS. 879** 880** Registered sqlite3_vfs objects are kept on a linked list formed by 881** the pNext pointer. The [sqlite3_vfs_register()] 882** and [sqlite3_vfs_unregister()] interfaces manage this list 883** in a thread-safe way. The [sqlite3_vfs_find()] interface 884** searches the list. Neither the application code nor the VFS 885** implementation should use the pNext pointer. 886** 887** The pNext field is the only field in the sqlite3_vfs 888** structure that SQLite will ever modify. SQLite will only access 889** or modify this field while holding a particular static mutex. 890** The application should never modify anything within the sqlite3_vfs 891** object once the object has been registered. 892** 893** The zName field holds the name of the VFS module. The name must 894** be unique across all VFS modules. 895** 896** [[sqlite3_vfs.xOpen]] 897** ^SQLite guarantees that the zFilename parameter to xOpen 898** is either a NULL pointer or string obtained 899** from xFullPathname() with an optional suffix added. 900** ^If a suffix is added to the zFilename parameter, it will 901** consist of a single "-" character followed by no more than 902** 11 alphanumeric and/or "-" characters. 903** ^SQLite further guarantees that 904** the string will be valid and unchanged until xClose() is 905** called. Because of the previous sentence, 906** the [sqlite3_file] can safely store a pointer to the 907** filename if it needs to remember the filename for some reason. 908** If the zFilename parameter to xOpen is a NULL pointer then xOpen 909** must invent its own temporary name for the file. ^Whenever the 910** xFilename parameter is NULL it will also be the case that the 911** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 912** 913** The flags argument to xOpen() includes all bits set in 914** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 915** or [sqlite3_open16()] is used, then flags includes at least 916** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 917** If xOpen() opens a file read-only then it sets *pOutFlags to 918** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 919** 920** ^(SQLite will also add one of the following flags to the xOpen() 921** call, depending on the object being opened: 922** 923** <ul> 924** <li> [SQLITE_OPEN_MAIN_DB] 925** <li> [SQLITE_OPEN_MAIN_JOURNAL] 926** <li> [SQLITE_OPEN_TEMP_DB] 927** <li> [SQLITE_OPEN_TEMP_JOURNAL] 928** <li> [SQLITE_OPEN_TRANSIENT_DB] 929** <li> [SQLITE_OPEN_SUBJOURNAL] 930** <li> [SQLITE_OPEN_MASTER_JOURNAL] 931** <li> [SQLITE_OPEN_WAL] 932** </ul>)^ 933** 934** The file I/O implementation can use the object type flags to 935** change the way it deals with files. For example, an application 936** that does not care about crash recovery or rollback might make 937** the open of a journal file a no-op. Writes to this journal would 938** also be no-ops, and any attempt to read the journal would return 939** SQLITE_IOERR. Or the implementation might recognize that a database 940** file will be doing page-aligned sector reads and writes in a random 941** order and set up its I/O subsystem accordingly. 942** 943** SQLite might also add one of the following flags to the xOpen method: 944** 945** <ul> 946** <li> [SQLITE_OPEN_DELETEONCLOSE] 947** <li> [SQLITE_OPEN_EXCLUSIVE] 948** </ul> 949** 950** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 951** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 952** will be set for TEMP databases and their journals, transient 953** databases, and subjournals. 954** 955** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 956** with the [SQLITE_OPEN_CREATE] flag, which are both directly 957** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 958** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 959** SQLITE_OPEN_CREATE, is used to indicate that file should always 960** be created, and that it is an error if it already exists. 961** It is <i>not</i> used to indicate the file should be opened 962** for exclusive access. 963** 964** ^At least szOsFile bytes of memory are allocated by SQLite 965** to hold the [sqlite3_file] structure passed as the third 966** argument to xOpen. The xOpen method does not have to 967** allocate the structure; it should just fill it in. Note that 968** the xOpen method must set the sqlite3_file.pMethods to either 969** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 970** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 971** element will be valid after xOpen returns regardless of the success 972** or failure of the xOpen call. 973** 974** [[sqlite3_vfs.xAccess]] 975** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 976** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 977** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 978** to test whether a file is at least readable. The file can be a 979** directory. 980** 981** ^SQLite will always allocate at least mxPathname+1 bytes for the 982** output buffer xFullPathname. The exact size of the output buffer 983** is also passed as a parameter to both methods. If the output buffer 984** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 985** handled as a fatal error by SQLite, vfs implementations should endeavor 986** to prevent this by setting mxPathname to a sufficiently large value. 987** 988** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 989** interfaces are not strictly a part of the filesystem, but they are 990** included in the VFS structure for completeness. 991** The xRandomness() function attempts to return nBytes bytes 992** of good-quality randomness into zOut. The return value is 993** the actual number of bytes of randomness obtained. 994** The xSleep() method causes the calling thread to sleep for at 995** least the number of microseconds given. ^The xCurrentTime() 996** method returns a Julian Day Number for the current date and time as 997** a floating point value. 998** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 999** Day Number multiplied by 86400000 (the number of milliseconds in 1000** a 24-hour day). 1001** ^SQLite will use the xCurrentTimeInt64() method to get the current 1002** date and time if that method is available (if iVersion is 2 or 1003** greater and the function pointer is not NULL) and will fall back 1004** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1005** 1006** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1007** are not used by the SQLite core. These optional interfaces are provided 1008** by some VFSes to facilitate testing of the VFS code. By overriding 1009** system calls with functions under its control, a test program can 1010** simulate faults and error conditions that would otherwise be difficult 1011** or impossible to induce. The set of system calls that can be overridden 1012** varies from one VFS to another, and from one version of the same VFS to the 1013** next. Applications that use these interfaces must be prepared for any 1014** or all of these interfaces to be NULL or for their behavior to change 1015** from one release to the next. Applications must not attempt to access 1016** any of these methods if the iVersion of the VFS is less than 3. 1017*/ 1018typedef struct sqlite3_vfs sqlite3_vfs; 1019typedef void (*sqlite3_syscall_ptr)(void); 1020struct sqlite3_vfs { 1021 int iVersion; /* Structure version number (currently 3) */ 1022 int szOsFile; /* Size of subclassed sqlite3_file */ 1023 int mxPathname; /* Maximum file pathname length */ 1024 sqlite3_vfs *pNext; /* Next registered VFS */ 1025 const char *zName; /* Name of this virtual file system */ 1026 void *pAppData; /* Pointer to application-specific data */ 1027 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1028 int flags, int *pOutFlags); 1029 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1030 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1031 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1032 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1033 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1034 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1035 void (*xDlClose)(sqlite3_vfs*, void*); 1036 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1037 int (*xSleep)(sqlite3_vfs*, int microseconds); 1038 int (*xCurrentTime)(sqlite3_vfs*, double*); 1039 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1040 /* 1041 ** The methods above are in version 1 of the sqlite_vfs object 1042 ** definition. Those that follow are added in version 2 or later 1043 */ 1044 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1045 /* 1046 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1047 ** Those below are for version 3 and greater. 1048 */ 1049 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1050 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1051 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1052 /* 1053 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1054 ** New fields may be appended in figure versions. The iVersion 1055 ** value will increment whenever this happens. 1056 */ 1057}; 1058 1059/* 1060** CAPI3REF: Flags for the xAccess VFS method 1061** 1062** These integer constants can be used as the third parameter to 1063** the xAccess method of an [sqlite3_vfs] object. They determine 1064** what kind of permissions the xAccess method is looking for. 1065** With SQLITE_ACCESS_EXISTS, the xAccess method 1066** simply checks whether the file exists. 1067** With SQLITE_ACCESS_READWRITE, the xAccess method 1068** checks whether the named directory is both readable and writable 1069** (in other words, if files can be added, removed, and renamed within 1070** the directory). 1071** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1072** [temp_store_directory pragma], though this could change in a future 1073** release of SQLite. 1074** With SQLITE_ACCESS_READ, the xAccess method 1075** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1076** currently unused, though it might be used in a future release of 1077** SQLite. 1078*/ 1079#define SQLITE_ACCESS_EXISTS 0 1080#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1081#define SQLITE_ACCESS_READ 2 /* Unused */ 1082 1083/* 1084** CAPI3REF: Flags for the xShmLock VFS method 1085** 1086** These integer constants define the various locking operations 1087** allowed by the xShmLock method of [sqlite3_io_methods]. The 1088** following are the only legal combinations of flags to the 1089** xShmLock method: 1090** 1091** <ul> 1092** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1093** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1094** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1095** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1096** </ul> 1097** 1098** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1099** was given no the corresponding lock. 1100** 1101** The xShmLock method can transition between unlocked and SHARED or 1102** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1103** and EXCLUSIVE. 1104*/ 1105#define SQLITE_SHM_UNLOCK 1 1106#define SQLITE_SHM_LOCK 2 1107#define SQLITE_SHM_SHARED 4 1108#define SQLITE_SHM_EXCLUSIVE 8 1109 1110/* 1111** CAPI3REF: Maximum xShmLock index 1112** 1113** The xShmLock method on [sqlite3_io_methods] may use values 1114** between 0 and this upper bound as its "offset" argument. 1115** The SQLite core will never attempt to acquire or release a 1116** lock outside of this range 1117*/ 1118#define SQLITE_SHM_NLOCK 8 1119 1120 1121/* 1122** CAPI3REF: Initialize The SQLite Library 1123** 1124** ^The sqlite3_initialize() routine initializes the 1125** SQLite library. ^The sqlite3_shutdown() routine 1126** deallocates any resources that were allocated by sqlite3_initialize(). 1127** These routines are designed to aid in process initialization and 1128** shutdown on embedded systems. Workstation applications using 1129** SQLite normally do not need to invoke either of these routines. 1130** 1131** A call to sqlite3_initialize() is an "effective" call if it is 1132** the first time sqlite3_initialize() is invoked during the lifetime of 1133** the process, or if it is the first time sqlite3_initialize() is invoked 1134** following a call to sqlite3_shutdown(). ^(Only an effective call 1135** of sqlite3_initialize() does any initialization. All other calls 1136** are harmless no-ops.)^ 1137** 1138** A call to sqlite3_shutdown() is an "effective" call if it is the first 1139** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1140** an effective call to sqlite3_shutdown() does any deinitialization. 1141** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1142** 1143** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1144** is not. The sqlite3_shutdown() interface must only be called from a 1145** single thread. All open [database connections] must be closed and all 1146** other SQLite resources must be deallocated prior to invoking 1147** sqlite3_shutdown(). 1148** 1149** Among other things, ^sqlite3_initialize() will invoke 1150** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1151** will invoke sqlite3_os_end(). 1152** 1153** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1154** ^If for some reason, sqlite3_initialize() is unable to initialize 1155** the library (perhaps it is unable to allocate a needed resource such 1156** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1157** 1158** ^The sqlite3_initialize() routine is called internally by many other 1159** SQLite interfaces so that an application usually does not need to 1160** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1161** calls sqlite3_initialize() so the SQLite library will be automatically 1162** initialized when [sqlite3_open()] is called if it has not be initialized 1163** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1164** compile-time option, then the automatic calls to sqlite3_initialize() 1165** are omitted and the application must call sqlite3_initialize() directly 1166** prior to using any other SQLite interface. For maximum portability, 1167** it is recommended that applications always invoke sqlite3_initialize() 1168** directly prior to using any other SQLite interface. Future releases 1169** of SQLite may require this. In other words, the behavior exhibited 1170** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1171** default behavior in some future release of SQLite. 1172** 1173** The sqlite3_os_init() routine does operating-system specific 1174** initialization of the SQLite library. The sqlite3_os_end() 1175** routine undoes the effect of sqlite3_os_init(). Typical tasks 1176** performed by these routines include allocation or deallocation 1177** of static resources, initialization of global variables, 1178** setting up a default [sqlite3_vfs] module, or setting up 1179** a default configuration using [sqlite3_config()]. 1180** 1181** The application should never invoke either sqlite3_os_init() 1182** or sqlite3_os_end() directly. The application should only invoke 1183** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1184** interface is called automatically by sqlite3_initialize() and 1185** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1186** implementations for sqlite3_os_init() and sqlite3_os_end() 1187** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1188** When [custom builds | built for other platforms] 1189** (using the [SQLITE_OS_OTHER=1] compile-time 1190** option) the application must supply a suitable implementation for 1191** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1192** implementation of sqlite3_os_init() or sqlite3_os_end() 1193** must return [SQLITE_OK] on success and some other [error code] upon 1194** failure. 1195*/ 1196int sqlite3_initialize(void); 1197int sqlite3_shutdown(void); 1198int sqlite3_os_init(void); 1199int sqlite3_os_end(void); 1200 1201/* 1202** CAPI3REF: Configuring The SQLite Library 1203** 1204** The sqlite3_config() interface is used to make global configuration 1205** changes to SQLite in order to tune SQLite to the specific needs of 1206** the application. The default configuration is recommended for most 1207** applications and so this routine is usually not necessary. It is 1208** provided to support rare applications with unusual needs. 1209** 1210** The sqlite3_config() interface is not threadsafe. The application 1211** must insure that no other SQLite interfaces are invoked by other 1212** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1213** may only be invoked prior to library initialization using 1214** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1215** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1216** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1217** Note, however, that ^sqlite3_config() can be called as part of the 1218** implementation of an application-defined [sqlite3_os_init()]. 1219** 1220** The first argument to sqlite3_config() is an integer 1221** [configuration option] that determines 1222** what property of SQLite is to be configured. Subsequent arguments 1223** vary depending on the [configuration option] 1224** in the first argument. 1225** 1226** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1227** ^If the option is unknown or SQLite is unable to set the option 1228** then this routine returns a non-zero [error code]. 1229*/ 1230int sqlite3_config(int, ...); 1231 1232/* 1233** CAPI3REF: Configure database connections 1234** 1235** The sqlite3_db_config() interface is used to make configuration 1236** changes to a [database connection]. The interface is similar to 1237** [sqlite3_config()] except that the changes apply to a single 1238** [database connection] (specified in the first argument). 1239** 1240** The second argument to sqlite3_db_config(D,V,...) is the 1241** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1242** that indicates what aspect of the [database connection] is being configured. 1243** Subsequent arguments vary depending on the configuration verb. 1244** 1245** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1246** the call is considered successful. 1247*/ 1248int sqlite3_db_config(sqlite3*, int op, ...); 1249 1250/* 1251** CAPI3REF: Memory Allocation Routines 1252** 1253** An instance of this object defines the interface between SQLite 1254** and low-level memory allocation routines. 1255** 1256** This object is used in only one place in the SQLite interface. 1257** A pointer to an instance of this object is the argument to 1258** [sqlite3_config()] when the configuration option is 1259** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1260** By creating an instance of this object 1261** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1262** during configuration, an application can specify an alternative 1263** memory allocation subsystem for SQLite to use for all of its 1264** dynamic memory needs. 1265** 1266** Note that SQLite comes with several [built-in memory allocators] 1267** that are perfectly adequate for the overwhelming majority of applications 1268** and that this object is only useful to a tiny minority of applications 1269** with specialized memory allocation requirements. This object is 1270** also used during testing of SQLite in order to specify an alternative 1271** memory allocator that simulates memory out-of-memory conditions in 1272** order to verify that SQLite recovers gracefully from such 1273** conditions. 1274** 1275** The xMalloc, xRealloc, and xFree methods must work like the 1276** malloc(), realloc() and free() functions from the standard C library. 1277** ^SQLite guarantees that the second argument to 1278** xRealloc is always a value returned by a prior call to xRoundup. 1279** 1280** xSize should return the allocated size of a memory allocation 1281** previously obtained from xMalloc or xRealloc. The allocated size 1282** is always at least as big as the requested size but may be larger. 1283** 1284** The xRoundup method returns what would be the allocated size of 1285** a memory allocation given a particular requested size. Most memory 1286** allocators round up memory allocations at least to the next multiple 1287** of 8. Some allocators round up to a larger multiple or to a power of 2. 1288** Every memory allocation request coming in through [sqlite3_malloc()] 1289** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1290** that causes the corresponding memory allocation to fail. 1291** 1292** The xInit method initializes the memory allocator. (For example, 1293** it might allocate any require mutexes or initialize internal data 1294** structures. The xShutdown method is invoked (indirectly) by 1295** [sqlite3_shutdown()] and should deallocate any resources acquired 1296** by xInit. The pAppData pointer is used as the only parameter to 1297** xInit and xShutdown. 1298** 1299** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1300** the xInit method, so the xInit method need not be threadsafe. The 1301** xShutdown method is only called from [sqlite3_shutdown()] so it does 1302** not need to be threadsafe either. For all other methods, SQLite 1303** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1304** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1305** it is by default) and so the methods are automatically serialized. 1306** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1307** methods must be threadsafe or else make their own arrangements for 1308** serialization. 1309** 1310** SQLite will never invoke xInit() more than once without an intervening 1311** call to xShutdown(). 1312*/ 1313typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1314struct sqlite3_mem_methods { 1315 void *(*xMalloc)(int); /* Memory allocation function */ 1316 void (*xFree)(void*); /* Free a prior allocation */ 1317 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1318 int (*xSize)(void*); /* Return the size of an allocation */ 1319 int (*xRoundup)(int); /* Round up request size to allocation size */ 1320 int (*xInit)(void*); /* Initialize the memory allocator */ 1321 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1322 void *pAppData; /* Argument to xInit() and xShutdown() */ 1323}; 1324 1325/* 1326** CAPI3REF: Configuration Options 1327** KEYWORDS: {configuration option} 1328** 1329** These constants are the available integer configuration options that 1330** can be passed as the first argument to the [sqlite3_config()] interface. 1331** 1332** New configuration options may be added in future releases of SQLite. 1333** Existing configuration options might be discontinued. Applications 1334** should check the return code from [sqlite3_config()] to make sure that 1335** the call worked. The [sqlite3_config()] interface will return a 1336** non-zero [error code] if a discontinued or unsupported configuration option 1337** is invoked. 1338** 1339** <dl> 1340** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1341** <dd>There are no arguments to this option. ^This option sets the 1342** [threading mode] to Single-thread. In other words, it disables 1343** all mutexing and puts SQLite into a mode where it can only be used 1344** by a single thread. ^If SQLite is compiled with 1345** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1346** it is not possible to change the [threading mode] from its default 1347** value of Single-thread and so [sqlite3_config()] will return 1348** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1349** configuration option.</dd> 1350** 1351** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1352** <dd>There are no arguments to this option. ^This option sets the 1353** [threading mode] to Multi-thread. In other words, it disables 1354** mutexing on [database connection] and [prepared statement] objects. 1355** The application is responsible for serializing access to 1356** [database connections] and [prepared statements]. But other mutexes 1357** are enabled so that SQLite will be safe to use in a multi-threaded 1358** environment as long as no two threads attempt to use the same 1359** [database connection] at the same time. ^If SQLite is compiled with 1360** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1361** it is not possible to set the Multi-thread [threading mode] and 1362** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1363** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1364** 1365** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1366** <dd>There are no arguments to this option. ^This option sets the 1367** [threading mode] to Serialized. In other words, this option enables 1368** all mutexes including the recursive 1369** mutexes on [database connection] and [prepared statement] objects. 1370** In this mode (which is the default when SQLite is compiled with 1371** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1372** to [database connections] and [prepared statements] so that the 1373** application is free to use the same [database connection] or the 1374** same [prepared statement] in different threads at the same time. 1375** ^If SQLite is compiled with 1376** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1377** it is not possible to set the Serialized [threading mode] and 1378** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1379** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1380** 1381** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1382** <dd> ^(This option takes a single argument which is a pointer to an 1383** instance of the [sqlite3_mem_methods] structure. The argument specifies 1384** alternative low-level memory allocation routines to be used in place of 1385** the memory allocation routines built into SQLite.)^ ^SQLite makes 1386** its own private copy of the content of the [sqlite3_mem_methods] structure 1387** before the [sqlite3_config()] call returns.</dd> 1388** 1389** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1390** <dd> ^(This option takes a single argument which is a pointer to an 1391** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1392** structure is filled with the currently defined memory allocation routines.)^ 1393** This option can be used to overload the default memory allocation 1394** routines with a wrapper that simulations memory allocation failure or 1395** tracks memory usage, for example. </dd> 1396** 1397** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1398** <dd> ^This option takes single argument of type int, interpreted as a 1399** boolean, which enables or disables the collection of memory allocation 1400** statistics. ^(When memory allocation statistics are disabled, the 1401** following SQLite interfaces become non-operational: 1402** <ul> 1403** <li> [sqlite3_memory_used()] 1404** <li> [sqlite3_memory_highwater()] 1405** <li> [sqlite3_soft_heap_limit64()] 1406** <li> [sqlite3_status()] 1407** </ul>)^ 1408** ^Memory allocation statistics are enabled by default unless SQLite is 1409** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1410** allocation statistics are disabled by default. 1411** </dd> 1412** 1413** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1414** <dd> ^This option specifies a static memory buffer that SQLite can use for 1415** scratch memory. There are three arguments: A pointer an 8-byte 1416** aligned memory buffer from which the scratch allocations will be 1417** drawn, the size of each scratch allocation (sz), 1418** and the maximum number of scratch allocations (N). The sz 1419** argument must be a multiple of 16. 1420** The first argument must be a pointer to an 8-byte aligned buffer 1421** of at least sz*N bytes of memory. 1422** ^SQLite will use no more than two scratch buffers per thread. So 1423** N should be set to twice the expected maximum number of threads. 1424** ^SQLite will never require a scratch buffer that is more than 6 1425** times the database page size. ^If SQLite needs needs additional 1426** scratch memory beyond what is provided by this configuration option, then 1427** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1428** 1429** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1430** <dd> ^This option specifies a static memory buffer that SQLite can use for 1431** the database page cache with the default page cache implementation. 1432** This configuration should not be used if an application-define page 1433** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option. 1434** There are three arguments to this option: A pointer to 8-byte aligned 1435** memory, the size of each page buffer (sz), and the number of pages (N). 1436** The sz argument should be the size of the largest database page 1437** (a power of two between 512 and 32768) plus a little extra for each 1438** page header. ^The page header size is 20 to 40 bytes depending on 1439** the host architecture. ^It is harmless, apart from the wasted memory, 1440** to make sz a little too large. The first 1441** argument should point to an allocation of at least sz*N bytes of memory. 1442** ^SQLite will use the memory provided by the first argument to satisfy its 1443** memory needs for the first N pages that it adds to cache. ^If additional 1444** page cache memory is needed beyond what is provided by this option, then 1445** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1446** The pointer in the first argument must 1447** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1448** will be undefined.</dd> 1449** 1450** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1451** <dd> ^This option specifies a static memory buffer that SQLite will use 1452** for all of its dynamic memory allocation needs beyond those provided 1453** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1454** There are three arguments: An 8-byte aligned pointer to the memory, 1455** the number of bytes in the memory buffer, and the minimum allocation size. 1456** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1457** to using its default memory allocator (the system malloc() implementation), 1458** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1459** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1460** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1461** allocator is engaged to handle all of SQLites memory allocation needs. 1462** The first pointer (the memory pointer) must be aligned to an 8-byte 1463** boundary or subsequent behavior of SQLite will be undefined. 1464** The minimum allocation size is capped at 2**12. Reasonable values 1465** for the minimum allocation size are 2**5 through 2**8.</dd> 1466** 1467** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1468** <dd> ^(This option takes a single argument which is a pointer to an 1469** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1470** alternative low-level mutex routines to be used in place 1471** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1472** content of the [sqlite3_mutex_methods] structure before the call to 1473** [sqlite3_config()] returns. ^If SQLite is compiled with 1474** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1475** the entire mutexing subsystem is omitted from the build and hence calls to 1476** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1477** return [SQLITE_ERROR].</dd> 1478** 1479** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1480** <dd> ^(This option takes a single argument which is a pointer to an 1481** instance of the [sqlite3_mutex_methods] structure. The 1482** [sqlite3_mutex_methods] 1483** structure is filled with the currently defined mutex routines.)^ 1484** This option can be used to overload the default mutex allocation 1485** routines with a wrapper used to track mutex usage for performance 1486** profiling or testing, for example. ^If SQLite is compiled with 1487** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1488** the entire mutexing subsystem is omitted from the build and hence calls to 1489** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1490** return [SQLITE_ERROR].</dd> 1491** 1492** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1493** <dd> ^(This option takes two arguments that determine the default 1494** memory allocation for the lookaside memory allocator on each 1495** [database connection]. The first argument is the 1496** size of each lookaside buffer slot and the second is the number of 1497** slots allocated to each database connection.)^ ^(This option sets the 1498** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1499** verb to [sqlite3_db_config()] can be used to change the lookaside 1500** configuration on individual connections.)^ </dd> 1501** 1502** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1503** <dd> ^(This option takes a single argument which is a pointer to 1504** an [sqlite3_pcache_methods2] object. This object specifies the interface 1505** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1506** object and uses it for page cache memory allocations.</dd> 1507** 1508** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1509** <dd> ^(This option takes a single argument which is a pointer to an 1510** [sqlite3_pcache_methods2] object. SQLite copies of the current 1511** page cache implementation into that object.)^ </dd> 1512** 1513** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1514** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1515** function with a call signature of void(*)(void*,int,const char*), 1516** and a pointer to void. ^If the function pointer is not NULL, it is 1517** invoked by [sqlite3_log()] to process each logging event. ^If the 1518** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1519** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1520** passed through as the first parameter to the application-defined logger 1521** function whenever that function is invoked. ^The second parameter to 1522** the logger function is a copy of the first parameter to the corresponding 1523** [sqlite3_log()] call and is intended to be a [result code] or an 1524** [extended result code]. ^The third parameter passed to the logger is 1525** log message after formatting via [sqlite3_snprintf()]. 1526** The SQLite logging interface is not reentrant; the logger function 1527** supplied by the application must not invoke any SQLite interface. 1528** In a multi-threaded application, the application-defined logger 1529** function must be threadsafe. </dd> 1530** 1531** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1532** <dd> This option takes a single argument of type int. If non-zero, then 1533** URI handling is globally enabled. If the parameter is zero, then URI handling 1534** is globally disabled. If URI handling is globally enabled, all filenames 1535** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1536** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1537** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1538** connection is opened. If it is globally disabled, filenames are 1539** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1540** database connection is opened. By default, URI handling is globally 1541** disabled. The default value may be changed by compiling with the 1542** [SQLITE_USE_URI] symbol defined. 1543** 1544** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1545** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1546** <dd> These options are obsolete and should not be used by new code. 1547** They are retained for backwards compatibility but are now no-ops. 1548** </dl> 1549*/ 1550#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1551#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1552#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1553#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1554#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1555#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1556#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1557#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1558#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1559#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1560#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1561/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1562#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1563#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1564#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1565#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1566#define SQLITE_CONFIG_URI 17 /* int */ 1567#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1568#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1569 1570/* 1571** CAPI3REF: Database Connection Configuration Options 1572** 1573** These constants are the available integer configuration options that 1574** can be passed as the second argument to the [sqlite3_db_config()] interface. 1575** 1576** New configuration options may be added in future releases of SQLite. 1577** Existing configuration options might be discontinued. Applications 1578** should check the return code from [sqlite3_db_config()] to make sure that 1579** the call worked. ^The [sqlite3_db_config()] interface will return a 1580** non-zero [error code] if a discontinued or unsupported configuration option 1581** is invoked. 1582** 1583** <dl> 1584** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1585** <dd> ^This option takes three additional arguments that determine the 1586** [lookaside memory allocator] configuration for the [database connection]. 1587** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1588** pointer to a memory buffer to use for lookaside memory. 1589** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1590** may be NULL in which case SQLite will allocate the 1591** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1592** size of each lookaside buffer slot. ^The third argument is the number of 1593** slots. The size of the buffer in the first argument must be greater than 1594** or equal to the product of the second and third arguments. The buffer 1595** must be aligned to an 8-byte boundary. ^If the second argument to 1596** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1597** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1598** configuration for a database connection can only be changed when that 1599** connection is not currently using lookaside memory, or in other words 1600** when the "current value" returned by 1601** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1602** Any attempt to change the lookaside memory configuration when lookaside 1603** memory is in use leaves the configuration unchanged and returns 1604** [SQLITE_BUSY].)^</dd> 1605** 1606** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1607** <dd> ^This option is used to enable or disable the enforcement of 1608** [foreign key constraints]. There should be two additional arguments. 1609** The first argument is an integer which is 0 to disable FK enforcement, 1610** positive to enable FK enforcement or negative to leave FK enforcement 1611** unchanged. The second parameter is a pointer to an integer into which 1612** is written 0 or 1 to indicate whether FK enforcement is off or on 1613** following this call. The second parameter may be a NULL pointer, in 1614** which case the FK enforcement setting is not reported back. </dd> 1615** 1616** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1617** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1618** There should be two additional arguments. 1619** The first argument is an integer which is 0 to disable triggers, 1620** positive to enable triggers or negative to leave the setting unchanged. 1621** The second parameter is a pointer to an integer into which 1622** is written 0 or 1 to indicate whether triggers are disabled or enabled 1623** following this call. The second parameter may be a NULL pointer, in 1624** which case the trigger setting is not reported back. </dd> 1625** 1626** </dl> 1627*/ 1628#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1629#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1630#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1631 1632 1633/* 1634** CAPI3REF: Enable Or Disable Extended Result Codes 1635** 1636** ^The sqlite3_extended_result_codes() routine enables or disables the 1637** [extended result codes] feature of SQLite. ^The extended result 1638** codes are disabled by default for historical compatibility. 1639*/ 1640int sqlite3_extended_result_codes(sqlite3*, int onoff); 1641 1642/* 1643** CAPI3REF: Last Insert Rowid 1644** 1645** ^Each entry in an SQLite table has a unique 64-bit signed 1646** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1647** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1648** names are not also used by explicitly declared columns. ^If 1649** the table has a column of type [INTEGER PRIMARY KEY] then that column 1650** is another alias for the rowid. 1651** 1652** ^This routine returns the [rowid] of the most recent 1653** successful [INSERT] into the database from the [database connection] 1654** in the first argument. ^As of SQLite version 3.7.7, this routines 1655** records the last insert rowid of both ordinary tables and [virtual tables]. 1656** ^If no successful [INSERT]s 1657** have ever occurred on that database connection, zero is returned. 1658** 1659** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1660** method, then this routine will return the [rowid] of the inserted 1661** row as long as the trigger or virtual table method is running. 1662** But once the trigger or virtual table method ends, the value returned 1663** by this routine reverts to what it was before the trigger or virtual 1664** table method began.)^ 1665** 1666** ^An [INSERT] that fails due to a constraint violation is not a 1667** successful [INSERT] and does not change the value returned by this 1668** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1669** and INSERT OR ABORT make no changes to the return value of this 1670** routine when their insertion fails. ^(When INSERT OR REPLACE 1671** encounters a constraint violation, it does not fail. The 1672** INSERT continues to completion after deleting rows that caused 1673** the constraint problem so INSERT OR REPLACE will always change 1674** the return value of this interface.)^ 1675** 1676** ^For the purposes of this routine, an [INSERT] is considered to 1677** be successful even if it is subsequently rolled back. 1678** 1679** This function is accessible to SQL statements via the 1680** [last_insert_rowid() SQL function]. 1681** 1682** If a separate thread performs a new [INSERT] on the same 1683** database connection while the [sqlite3_last_insert_rowid()] 1684** function is running and thus changes the last insert [rowid], 1685** then the value returned by [sqlite3_last_insert_rowid()] is 1686** unpredictable and might not equal either the old or the new 1687** last insert [rowid]. 1688*/ 1689sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1690 1691/* 1692** CAPI3REF: Count The Number Of Rows Modified 1693** 1694** ^This function returns the number of database rows that were changed 1695** or inserted or deleted by the most recently completed SQL statement 1696** on the [database connection] specified by the first parameter. 1697** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1698** or [DELETE] statement are counted. Auxiliary changes caused by 1699** triggers or [foreign key actions] are not counted.)^ Use the 1700** [sqlite3_total_changes()] function to find the total number of changes 1701** including changes caused by triggers and foreign key actions. 1702** 1703** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1704** are not counted. Only real table changes are counted. 1705** 1706** ^(A "row change" is a change to a single row of a single table 1707** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1708** are changed as side effects of [REPLACE] constraint resolution, 1709** rollback, ABORT processing, [DROP TABLE], or by any other 1710** mechanisms do not count as direct row changes.)^ 1711** 1712** A "trigger context" is a scope of execution that begins and 1713** ends with the script of a [CREATE TRIGGER | trigger]. 1714** Most SQL statements are 1715** evaluated outside of any trigger. This is the "top level" 1716** trigger context. If a trigger fires from the top level, a 1717** new trigger context is entered for the duration of that one 1718** trigger. Subtriggers create subcontexts for their duration. 1719** 1720** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1721** not create a new trigger context. 1722** 1723** ^This function returns the number of direct row changes in the 1724** most recent INSERT, UPDATE, or DELETE statement within the same 1725** trigger context. 1726** 1727** ^Thus, when called from the top level, this function returns the 1728** number of changes in the most recent INSERT, UPDATE, or DELETE 1729** that also occurred at the top level. ^(Within the body of a trigger, 1730** the sqlite3_changes() interface can be called to find the number of 1731** changes in the most recently completed INSERT, UPDATE, or DELETE 1732** statement within the body of the same trigger. 1733** However, the number returned does not include changes 1734** caused by subtriggers since those have their own context.)^ 1735** 1736** See also the [sqlite3_total_changes()] interface, the 1737** [count_changes pragma], and the [changes() SQL function]. 1738** 1739** If a separate thread makes changes on the same database connection 1740** while [sqlite3_changes()] is running then the value returned 1741** is unpredictable and not meaningful. 1742*/ 1743int sqlite3_changes(sqlite3*); 1744 1745/* 1746** CAPI3REF: Total Number Of Rows Modified 1747** 1748** ^This function returns the number of row changes caused by [INSERT], 1749** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1750** ^(The count returned by sqlite3_total_changes() includes all changes 1751** from all [CREATE TRIGGER | trigger] contexts and changes made by 1752** [foreign key actions]. However, 1753** the count does not include changes used to implement [REPLACE] constraints, 1754** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1755** count does not include rows of views that fire an [INSTEAD OF trigger], 1756** though if the INSTEAD OF trigger makes changes of its own, those changes 1757** are counted.)^ 1758** ^The sqlite3_total_changes() function counts the changes as soon as 1759** the statement that makes them is completed (when the statement handle 1760** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1761** 1762** See also the [sqlite3_changes()] interface, the 1763** [count_changes pragma], and the [total_changes() SQL function]. 1764** 1765** If a separate thread makes changes on the same database connection 1766** while [sqlite3_total_changes()] is running then the value 1767** returned is unpredictable and not meaningful. 1768*/ 1769int sqlite3_total_changes(sqlite3*); 1770 1771/* 1772** CAPI3REF: Interrupt A Long-Running Query 1773** 1774** ^This function causes any pending database operation to abort and 1775** return at its earliest opportunity. This routine is typically 1776** called in response to a user action such as pressing "Cancel" 1777** or Ctrl-C where the user wants a long query operation to halt 1778** immediately. 1779** 1780** ^It is safe to call this routine from a thread different from the 1781** thread that is currently running the database operation. But it 1782** is not safe to call this routine with a [database connection] that 1783** is closed or might close before sqlite3_interrupt() returns. 1784** 1785** ^If an SQL operation is very nearly finished at the time when 1786** sqlite3_interrupt() is called, then it might not have an opportunity 1787** to be interrupted and might continue to completion. 1788** 1789** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1790** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1791** that is inside an explicit transaction, then the entire transaction 1792** will be rolled back automatically. 1793** 1794** ^The sqlite3_interrupt(D) call is in effect until all currently running 1795** SQL statements on [database connection] D complete. ^Any new SQL statements 1796** that are started after the sqlite3_interrupt() call and before the 1797** running statements reaches zero are interrupted as if they had been 1798** running prior to the sqlite3_interrupt() call. ^New SQL statements 1799** that are started after the running statement count reaches zero are 1800** not effected by the sqlite3_interrupt(). 1801** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1802** SQL statements is a no-op and has no effect on SQL statements 1803** that are started after the sqlite3_interrupt() call returns. 1804** 1805** If the database connection closes while [sqlite3_interrupt()] 1806** is running then bad things will likely happen. 1807*/ 1808void sqlite3_interrupt(sqlite3*); 1809 1810/* 1811** CAPI3REF: Determine If An SQL Statement Is Complete 1812** 1813** These routines are useful during command-line input to determine if the 1814** currently entered text seems to form a complete SQL statement or 1815** if additional input is needed before sending the text into 1816** SQLite for parsing. ^These routines return 1 if the input string 1817** appears to be a complete SQL statement. ^A statement is judged to be 1818** complete if it ends with a semicolon token and is not a prefix of a 1819** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1820** string literals or quoted identifier names or comments are not 1821** independent tokens (they are part of the token in which they are 1822** embedded) and thus do not count as a statement terminator. ^Whitespace 1823** and comments that follow the final semicolon are ignored. 1824** 1825** ^These routines return 0 if the statement is incomplete. ^If a 1826** memory allocation fails, then SQLITE_NOMEM is returned. 1827** 1828** ^These routines do not parse the SQL statements thus 1829** will not detect syntactically incorrect SQL. 1830** 1831** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1832** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1833** automatically by sqlite3_complete16(). If that initialization fails, 1834** then the return value from sqlite3_complete16() will be non-zero 1835** regardless of whether or not the input SQL is complete.)^ 1836** 1837** The input to [sqlite3_complete()] must be a zero-terminated 1838** UTF-8 string. 1839** 1840** The input to [sqlite3_complete16()] must be a zero-terminated 1841** UTF-16 string in native byte order. 1842*/ 1843int sqlite3_complete(const char *sql); 1844int sqlite3_complete16(const void *sql); 1845 1846/* 1847** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1848** 1849** ^This routine sets a callback function that might be invoked whenever 1850** an attempt is made to open a database table that another thread 1851** or process has locked. 1852** 1853** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1854** is returned immediately upon encountering the lock. ^If the busy callback 1855** is not NULL, then the callback might be invoked with two arguments. 1856** 1857** ^The first argument to the busy handler is a copy of the void* pointer which 1858** is the third argument to sqlite3_busy_handler(). ^The second argument to 1859** the busy handler callback is the number of times that the busy handler has 1860** been invoked for this locking event. ^If the 1861** busy callback returns 0, then no additional attempts are made to 1862** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1863** ^If the callback returns non-zero, then another attempt 1864** is made to open the database for reading and the cycle repeats. 1865** 1866** The presence of a busy handler does not guarantee that it will be invoked 1867** when there is lock contention. ^If SQLite determines that invoking the busy 1868** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1869** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1870** Consider a scenario where one process is holding a read lock that 1871** it is trying to promote to a reserved lock and 1872** a second process is holding a reserved lock that it is trying 1873** to promote to an exclusive lock. The first process cannot proceed 1874** because it is blocked by the second and the second process cannot 1875** proceed because it is blocked by the first. If both processes 1876** invoke the busy handlers, neither will make any progress. Therefore, 1877** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1878** will induce the first process to release its read lock and allow 1879** the second process to proceed. 1880** 1881** ^The default busy callback is NULL. 1882** 1883** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1884** when SQLite is in the middle of a large transaction where all the 1885** changes will not fit into the in-memory cache. SQLite will 1886** already hold a RESERVED lock on the database file, but it needs 1887** to promote this lock to EXCLUSIVE so that it can spill cache 1888** pages into the database file without harm to concurrent 1889** readers. ^If it is unable to promote the lock, then the in-memory 1890** cache will be left in an inconsistent state and so the error 1891** code is promoted from the relatively benign [SQLITE_BUSY] to 1892** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1893** forces an automatic rollback of the changes. See the 1894** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1895** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1896** this is important. 1897** 1898** ^(There can only be a single busy handler defined for each 1899** [database connection]. Setting a new busy handler clears any 1900** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1901** will also set or clear the busy handler. 1902** 1903** The busy callback should not take any actions which modify the 1904** database connection that invoked the busy handler. Any such actions 1905** result in undefined behavior. 1906** 1907** A busy handler must not close the database connection 1908** or [prepared statement] that invoked the busy handler. 1909*/ 1910int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1911 1912/* 1913** CAPI3REF: Set A Busy Timeout 1914** 1915** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1916** for a specified amount of time when a table is locked. ^The handler 1917** will sleep multiple times until at least "ms" milliseconds of sleeping 1918** have accumulated. ^After at least "ms" milliseconds of sleeping, 1919** the handler returns 0 which causes [sqlite3_step()] to return 1920** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1921** 1922** ^Calling this routine with an argument less than or equal to zero 1923** turns off all busy handlers. 1924** 1925** ^(There can only be a single busy handler for a particular 1926** [database connection] any any given moment. If another busy handler 1927** was defined (using [sqlite3_busy_handler()]) prior to calling 1928** this routine, that other busy handler is cleared.)^ 1929*/ 1930int sqlite3_busy_timeout(sqlite3*, int ms); 1931 1932/* 1933** CAPI3REF: Convenience Routines For Running Queries 1934** 1935** This is a legacy interface that is preserved for backwards compatibility. 1936** Use of this interface is not recommended. 1937** 1938** Definition: A <b>result table</b> is memory data structure created by the 1939** [sqlite3_get_table()] interface. A result table records the 1940** complete query results from one or more queries. 1941** 1942** The table conceptually has a number of rows and columns. But 1943** these numbers are not part of the result table itself. These 1944** numbers are obtained separately. Let N be the number of rows 1945** and M be the number of columns. 1946** 1947** A result table is an array of pointers to zero-terminated UTF-8 strings. 1948** There are (N+1)*M elements in the array. The first M pointers point 1949** to zero-terminated strings that contain the names of the columns. 1950** The remaining entries all point to query results. NULL values result 1951** in NULL pointers. All other values are in their UTF-8 zero-terminated 1952** string representation as returned by [sqlite3_column_text()]. 1953** 1954** A result table might consist of one or more memory allocations. 1955** It is not safe to pass a result table directly to [sqlite3_free()]. 1956** A result table should be deallocated using [sqlite3_free_table()]. 1957** 1958** ^(As an example of the result table format, suppose a query result 1959** is as follows: 1960** 1961** <blockquote><pre> 1962** Name | Age 1963** ----------------------- 1964** Alice | 43 1965** Bob | 28 1966** Cindy | 21 1967** </pre></blockquote> 1968** 1969** There are two column (M==2) and three rows (N==3). Thus the 1970** result table has 8 entries. Suppose the result table is stored 1971** in an array names azResult. Then azResult holds this content: 1972** 1973** <blockquote><pre> 1974** azResult[0] = "Name"; 1975** azResult[1] = "Age"; 1976** azResult[2] = "Alice"; 1977** azResult[3] = "43"; 1978** azResult[4] = "Bob"; 1979** azResult[5] = "28"; 1980** azResult[6] = "Cindy"; 1981** azResult[7] = "21"; 1982** </pre></blockquote>)^ 1983** 1984** ^The sqlite3_get_table() function evaluates one or more 1985** semicolon-separated SQL statements in the zero-terminated UTF-8 1986** string of its 2nd parameter and returns a result table to the 1987** pointer given in its 3rd parameter. 1988** 1989** After the application has finished with the result from sqlite3_get_table(), 1990** it must pass the result table pointer to sqlite3_free_table() in order to 1991** release the memory that was malloced. Because of the way the 1992** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1993** function must not try to call [sqlite3_free()] directly. Only 1994** [sqlite3_free_table()] is able to release the memory properly and safely. 1995** 1996** The sqlite3_get_table() interface is implemented as a wrapper around 1997** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1998** to any internal data structures of SQLite. It uses only the public 1999** interface defined here. As a consequence, errors that occur in the 2000** wrapper layer outside of the internal [sqlite3_exec()] call are not 2001** reflected in subsequent calls to [sqlite3_errcode()] or 2002** [sqlite3_errmsg()]. 2003*/ 2004int sqlite3_get_table( 2005 sqlite3 *db, /* An open database */ 2006 const char *zSql, /* SQL to be evaluated */ 2007 char ***pazResult, /* Results of the query */ 2008 int *pnRow, /* Number of result rows written here */ 2009 int *pnColumn, /* Number of result columns written here */ 2010 char **pzErrmsg /* Error msg written here */ 2011); 2012void sqlite3_free_table(char **result); 2013 2014/* 2015** CAPI3REF: Formatted String Printing Functions 2016** 2017** These routines are work-alikes of the "printf()" family of functions 2018** from the standard C library. 2019** 2020** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2021** results into memory obtained from [sqlite3_malloc()]. 2022** The strings returned by these two routines should be 2023** released by [sqlite3_free()]. ^Both routines return a 2024** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2025** memory to hold the resulting string. 2026** 2027** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2028** the standard C library. The result is written into the 2029** buffer supplied as the second parameter whose size is given by 2030** the first parameter. Note that the order of the 2031** first two parameters is reversed from snprintf().)^ This is an 2032** historical accident that cannot be fixed without breaking 2033** backwards compatibility. ^(Note also that sqlite3_snprintf() 2034** returns a pointer to its buffer instead of the number of 2035** characters actually written into the buffer.)^ We admit that 2036** the number of characters written would be a more useful return 2037** value but we cannot change the implementation of sqlite3_snprintf() 2038** now without breaking compatibility. 2039** 2040** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2041** guarantees that the buffer is always zero-terminated. ^The first 2042** parameter "n" is the total size of the buffer, including space for 2043** the zero terminator. So the longest string that can be completely 2044** written will be n-1 characters. 2045** 2046** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2047** 2048** These routines all implement some additional formatting 2049** options that are useful for constructing SQL statements. 2050** All of the usual printf() formatting options apply. In addition, there 2051** is are "%q", "%Q", and "%z" options. 2052** 2053** ^(The %q option works like %s in that it substitutes a nul-terminated 2054** string from the argument list. But %q also doubles every '\'' character. 2055** %q is designed for use inside a string literal.)^ By doubling each '\'' 2056** character it escapes that character and allows it to be inserted into 2057** the string. 2058** 2059** For example, assume the string variable zText contains text as follows: 2060** 2061** <blockquote><pre> 2062** char *zText = "It's a happy day!"; 2063** </pre></blockquote> 2064** 2065** One can use this text in an SQL statement as follows: 2066** 2067** <blockquote><pre> 2068** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2069** sqlite3_exec(db, zSQL, 0, 0, 0); 2070** sqlite3_free(zSQL); 2071** </pre></blockquote> 2072** 2073** Because the %q format string is used, the '\'' character in zText 2074** is escaped and the SQL generated is as follows: 2075** 2076** <blockquote><pre> 2077** INSERT INTO table1 VALUES('It''s a happy day!') 2078** </pre></blockquote> 2079** 2080** This is correct. Had we used %s instead of %q, the generated SQL 2081** would have looked like this: 2082** 2083** <blockquote><pre> 2084** INSERT INTO table1 VALUES('It's a happy day!'); 2085** </pre></blockquote> 2086** 2087** This second example is an SQL syntax error. As a general rule you should 2088** always use %q instead of %s when inserting text into a string literal. 2089** 2090** ^(The %Q option works like %q except it also adds single quotes around 2091** the outside of the total string. Additionally, if the parameter in the 2092** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2093** single quotes).)^ So, for example, one could say: 2094** 2095** <blockquote><pre> 2096** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2097** sqlite3_exec(db, zSQL, 0, 0, 0); 2098** sqlite3_free(zSQL); 2099** </pre></blockquote> 2100** 2101** The code above will render a correct SQL statement in the zSQL 2102** variable even if the zText variable is a NULL pointer. 2103** 2104** ^(The "%z" formatting option works like "%s" but with the 2105** addition that after the string has been read and copied into 2106** the result, [sqlite3_free()] is called on the input string.)^ 2107*/ 2108char *sqlite3_mprintf(const char*,...); 2109char *sqlite3_vmprintf(const char*, va_list); 2110char *sqlite3_snprintf(int,char*,const char*, ...); 2111char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2112 2113/* 2114** CAPI3REF: Memory Allocation Subsystem 2115** 2116** The SQLite core uses these three routines for all of its own 2117** internal memory allocation needs. "Core" in the previous sentence 2118** does not include operating-system specific VFS implementation. The 2119** Windows VFS uses native malloc() and free() for some operations. 2120** 2121** ^The sqlite3_malloc() routine returns a pointer to a block 2122** of memory at least N bytes in length, where N is the parameter. 2123** ^If sqlite3_malloc() is unable to obtain sufficient free 2124** memory, it returns a NULL pointer. ^If the parameter N to 2125** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2126** a NULL pointer. 2127** 2128** ^Calling sqlite3_free() with a pointer previously returned 2129** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2130** that it might be reused. ^The sqlite3_free() routine is 2131** a no-op if is called with a NULL pointer. Passing a NULL pointer 2132** to sqlite3_free() is harmless. After being freed, memory 2133** should neither be read nor written. Even reading previously freed 2134** memory might result in a segmentation fault or other severe error. 2135** Memory corruption, a segmentation fault, or other severe error 2136** might result if sqlite3_free() is called with a non-NULL pointer that 2137** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2138** 2139** ^(The sqlite3_realloc() interface attempts to resize a 2140** prior memory allocation to be at least N bytes, where N is the 2141** second parameter. The memory allocation to be resized is the first 2142** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2143** is a NULL pointer then its behavior is identical to calling 2144** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2145** ^If the second parameter to sqlite3_realloc() is zero or 2146** negative then the behavior is exactly the same as calling 2147** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2148** ^sqlite3_realloc() returns a pointer to a memory allocation 2149** of at least N bytes in size or NULL if sufficient memory is unavailable. 2150** ^If M is the size of the prior allocation, then min(N,M) bytes 2151** of the prior allocation are copied into the beginning of buffer returned 2152** by sqlite3_realloc() and the prior allocation is freed. 2153** ^If sqlite3_realloc() returns NULL, then the prior allocation 2154** is not freed. 2155** 2156** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2157** is always aligned to at least an 8 byte boundary, or to a 2158** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2159** option is used. 2160** 2161** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2162** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2163** implementation of these routines to be omitted. That capability 2164** is no longer provided. Only built-in memory allocators can be used. 2165** 2166** The Windows OS interface layer calls 2167** the system malloc() and free() directly when converting 2168** filenames between the UTF-8 encoding used by SQLite 2169** and whatever filename encoding is used by the particular Windows 2170** installation. Memory allocation errors are detected, but 2171** they are reported back as [SQLITE_CANTOPEN] or 2172** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2173** 2174** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2175** must be either NULL or else pointers obtained from a prior 2176** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2177** not yet been released. 2178** 2179** The application must not read or write any part of 2180** a block of memory after it has been released using 2181** [sqlite3_free()] or [sqlite3_realloc()]. 2182*/ 2183void *sqlite3_malloc(int); 2184void *sqlite3_realloc(void*, int); 2185void sqlite3_free(void*); 2186 2187/* 2188** CAPI3REF: Memory Allocator Statistics 2189** 2190** SQLite provides these two interfaces for reporting on the status 2191** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2192** routines, which form the built-in memory allocation subsystem. 2193** 2194** ^The [sqlite3_memory_used()] routine returns the number of bytes 2195** of memory currently outstanding (malloced but not freed). 2196** ^The [sqlite3_memory_highwater()] routine returns the maximum 2197** value of [sqlite3_memory_used()] since the high-water mark 2198** was last reset. ^The values returned by [sqlite3_memory_used()] and 2199** [sqlite3_memory_highwater()] include any overhead 2200** added by SQLite in its implementation of [sqlite3_malloc()], 2201** but not overhead added by the any underlying system library 2202** routines that [sqlite3_malloc()] may call. 2203** 2204** ^The memory high-water mark is reset to the current value of 2205** [sqlite3_memory_used()] if and only if the parameter to 2206** [sqlite3_memory_highwater()] is true. ^The value returned 2207** by [sqlite3_memory_highwater(1)] is the high-water mark 2208** prior to the reset. 2209*/ 2210sqlite3_int64 sqlite3_memory_used(void); 2211sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2212 2213/* 2214** CAPI3REF: Pseudo-Random Number Generator 2215** 2216** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2217** select random [ROWID | ROWIDs] when inserting new records into a table that 2218** already uses the largest possible [ROWID]. The PRNG is also used for 2219** the build-in random() and randomblob() SQL functions. This interface allows 2220** applications to access the same PRNG for other purposes. 2221** 2222** ^A call to this routine stores N bytes of randomness into buffer P. 2223** 2224** ^The first time this routine is invoked (either internally or by 2225** the application) the PRNG is seeded using randomness obtained 2226** from the xRandomness method of the default [sqlite3_vfs] object. 2227** ^On all subsequent invocations, the pseudo-randomness is generated 2228** internally and without recourse to the [sqlite3_vfs] xRandomness 2229** method. 2230*/ 2231void sqlite3_randomness(int N, void *P); 2232 2233/* 2234** CAPI3REF: Compile-Time Authorization Callbacks 2235** 2236** ^This routine registers an authorizer callback with a particular 2237** [database connection], supplied in the first argument. 2238** ^The authorizer callback is invoked as SQL statements are being compiled 2239** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2240** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2241** points during the compilation process, as logic is being created 2242** to perform various actions, the authorizer callback is invoked to 2243** see if those actions are allowed. ^The authorizer callback should 2244** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2245** specific action but allow the SQL statement to continue to be 2246** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2247** rejected with an error. ^If the authorizer callback returns 2248** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2249** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2250** the authorizer will fail with an error message. 2251** 2252** When the callback returns [SQLITE_OK], that means the operation 2253** requested is ok. ^When the callback returns [SQLITE_DENY], the 2254** [sqlite3_prepare_v2()] or equivalent call that triggered the 2255** authorizer will fail with an error message explaining that 2256** access is denied. 2257** 2258** ^The first parameter to the authorizer callback is a copy of the third 2259** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2260** to the callback is an integer [SQLITE_COPY | action code] that specifies 2261** the particular action to be authorized. ^The third through sixth parameters 2262** to the callback are zero-terminated strings that contain additional 2263** details about the action to be authorized. 2264** 2265** ^If the action code is [SQLITE_READ] 2266** and the callback returns [SQLITE_IGNORE] then the 2267** [prepared statement] statement is constructed to substitute 2268** a NULL value in place of the table column that would have 2269** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2270** return can be used to deny an untrusted user access to individual 2271** columns of a table. 2272** ^If the action code is [SQLITE_DELETE] and the callback returns 2273** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2274** [truncate optimization] is disabled and all rows are deleted individually. 2275** 2276** An authorizer is used when [sqlite3_prepare | preparing] 2277** SQL statements from an untrusted source, to ensure that the SQL statements 2278** do not try to access data they are not allowed to see, or that they do not 2279** try to execute malicious statements that damage the database. For 2280** example, an application may allow a user to enter arbitrary 2281** SQL queries for evaluation by a database. But the application does 2282** not want the user to be able to make arbitrary changes to the 2283** database. An authorizer could then be put in place while the 2284** user-entered SQL is being [sqlite3_prepare | prepared] that 2285** disallows everything except [SELECT] statements. 2286** 2287** Applications that need to process SQL from untrusted sources 2288** might also consider lowering resource limits using [sqlite3_limit()] 2289** and limiting database size using the [max_page_count] [PRAGMA] 2290** in addition to using an authorizer. 2291** 2292** ^(Only a single authorizer can be in place on a database connection 2293** at a time. Each call to sqlite3_set_authorizer overrides the 2294** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2295** The authorizer is disabled by default. 2296** 2297** The authorizer callback must not do anything that will modify 2298** the database connection that invoked the authorizer callback. 2299** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2300** database connections for the meaning of "modify" in this paragraph. 2301** 2302** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2303** statement might be re-prepared during [sqlite3_step()] due to a 2304** schema change. Hence, the application should ensure that the 2305** correct authorizer callback remains in place during the [sqlite3_step()]. 2306** 2307** ^Note that the authorizer callback is invoked only during 2308** [sqlite3_prepare()] or its variants. Authorization is not 2309** performed during statement evaluation in [sqlite3_step()], unless 2310** as stated in the previous paragraph, sqlite3_step() invokes 2311** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2312*/ 2313int sqlite3_set_authorizer( 2314 sqlite3*, 2315 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2316 void *pUserData 2317); 2318 2319/* 2320** CAPI3REF: Authorizer Return Codes 2321** 2322** The [sqlite3_set_authorizer | authorizer callback function] must 2323** return either [SQLITE_OK] or one of these two constants in order 2324** to signal SQLite whether or not the action is permitted. See the 2325** [sqlite3_set_authorizer | authorizer documentation] for additional 2326** information. 2327** 2328** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2329** from the [sqlite3_vtab_on_conflict()] interface. 2330*/ 2331#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2332#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2333 2334/* 2335** CAPI3REF: Authorizer Action Codes 2336** 2337** The [sqlite3_set_authorizer()] interface registers a callback function 2338** that is invoked to authorize certain SQL statement actions. The 2339** second parameter to the callback is an integer code that specifies 2340** what action is being authorized. These are the integer action codes that 2341** the authorizer callback may be passed. 2342** 2343** These action code values signify what kind of operation is to be 2344** authorized. The 3rd and 4th parameters to the authorization 2345** callback function will be parameters or NULL depending on which of these 2346** codes is used as the second parameter. ^(The 5th parameter to the 2347** authorizer callback is the name of the database ("main", "temp", 2348** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2349** is the name of the inner-most trigger or view that is responsible for 2350** the access attempt or NULL if this access attempt is directly from 2351** top-level SQL code. 2352*/ 2353/******************************************* 3rd ************ 4th ***********/ 2354#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2355#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2356#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2357#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2358#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2359#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2360#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2361#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2362#define SQLITE_DELETE 9 /* Table Name NULL */ 2363#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2364#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2365#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2366#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2367#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2368#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2369#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2370#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2371#define SQLITE_INSERT 18 /* Table Name NULL */ 2372#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2373#define SQLITE_READ 20 /* Table Name Column Name */ 2374#define SQLITE_SELECT 21 /* NULL NULL */ 2375#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2376#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2377#define SQLITE_ATTACH 24 /* Filename NULL */ 2378#define SQLITE_DETACH 25 /* Database Name NULL */ 2379#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2380#define SQLITE_REINDEX 27 /* Index Name NULL */ 2381#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2382#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2383#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2384#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2385#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2386#define SQLITE_COPY 0 /* No longer used */ 2387 2388/* 2389** CAPI3REF: Tracing And Profiling Functions 2390** 2391** These routines register callback functions that can be used for 2392** tracing and profiling the execution of SQL statements. 2393** 2394** ^The callback function registered by sqlite3_trace() is invoked at 2395** various times when an SQL statement is being run by [sqlite3_step()]. 2396** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2397** SQL statement text as the statement first begins executing. 2398** ^(Additional sqlite3_trace() callbacks might occur 2399** as each triggered subprogram is entered. The callbacks for triggers 2400** contain a UTF-8 SQL comment that identifies the trigger.)^ 2401** 2402** ^The callback function registered by sqlite3_profile() is invoked 2403** as each SQL statement finishes. ^The profile callback contains 2404** the original statement text and an estimate of wall-clock time 2405** of how long that statement took to run. ^The profile callback 2406** time is in units of nanoseconds, however the current implementation 2407** is only capable of millisecond resolution so the six least significant 2408** digits in the time are meaningless. Future versions of SQLite 2409** might provide greater resolution on the profiler callback. The 2410** sqlite3_profile() function is considered experimental and is 2411** subject to change in future versions of SQLite. 2412*/ 2413void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2414SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2415 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2416 2417/* 2418** CAPI3REF: Query Progress Callbacks 2419** 2420** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2421** function X to be invoked periodically during long running calls to 2422** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2423** database connection D. An example use for this 2424** interface is to keep a GUI updated during a large query. 2425** 2426** ^The parameter P is passed through as the only parameter to the 2427** callback function X. ^The parameter N is the number of 2428** [virtual machine instructions] that are evaluated between successive 2429** invocations of the callback X. 2430** 2431** ^Only a single progress handler may be defined at one time per 2432** [database connection]; setting a new progress handler cancels the 2433** old one. ^Setting parameter X to NULL disables the progress handler. 2434** ^The progress handler is also disabled by setting N to a value less 2435** than 1. 2436** 2437** ^If the progress callback returns non-zero, the operation is 2438** interrupted. This feature can be used to implement a 2439** "Cancel" button on a GUI progress dialog box. 2440** 2441** The progress handler callback must not do anything that will modify 2442** the database connection that invoked the progress handler. 2443** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2444** database connections for the meaning of "modify" in this paragraph. 2445** 2446*/ 2447void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2448 2449/* 2450** CAPI3REF: Opening A New Database Connection 2451** 2452** ^These routines open an SQLite database file as specified by the 2453** filename argument. ^The filename argument is interpreted as UTF-8 for 2454** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2455** order for sqlite3_open16(). ^(A [database connection] handle is usually 2456** returned in *ppDb, even if an error occurs. The only exception is that 2457** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2458** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2459** object.)^ ^(If the database is opened (and/or created) successfully, then 2460** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2461** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2462** an English language description of the error following a failure of any 2463** of the sqlite3_open() routines. 2464** 2465** ^The default encoding for the database will be UTF-8 if 2466** sqlite3_open() or sqlite3_open_v2() is called and 2467** UTF-16 in the native byte order if sqlite3_open16() is used. 2468** 2469** Whether or not an error occurs when it is opened, resources 2470** associated with the [database connection] handle should be released by 2471** passing it to [sqlite3_close()] when it is no longer required. 2472** 2473** The sqlite3_open_v2() interface works like sqlite3_open() 2474** except that it accepts two additional parameters for additional control 2475** over the new database connection. ^(The flags parameter to 2476** sqlite3_open_v2() can take one of 2477** the following three values, optionally combined with the 2478** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2479** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2480** 2481** <dl> 2482** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2483** <dd>The database is opened in read-only mode. If the database does not 2484** already exist, an error is returned.</dd>)^ 2485** 2486** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2487** <dd>The database is opened for reading and writing if possible, or reading 2488** only if the file is write protected by the operating system. In either 2489** case the database must already exist, otherwise an error is returned.</dd>)^ 2490** 2491** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2492** <dd>The database is opened for reading and writing, and is created if 2493** it does not already exist. This is the behavior that is always used for 2494** sqlite3_open() and sqlite3_open16().</dd>)^ 2495** </dl> 2496** 2497** If the 3rd parameter to sqlite3_open_v2() is not one of the 2498** combinations shown above optionally combined with other 2499** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2500** then the behavior is undefined. 2501** 2502** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2503** opens in the multi-thread [threading mode] as long as the single-thread 2504** mode has not been set at compile-time or start-time. ^If the 2505** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2506** in the serialized [threading mode] unless single-thread was 2507** previously selected at compile-time or start-time. 2508** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2509** eligible to use [shared cache mode], regardless of whether or not shared 2510** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2511** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2512** participate in [shared cache mode] even if it is enabled. 2513** 2514** ^The fourth parameter to sqlite3_open_v2() is the name of the 2515** [sqlite3_vfs] object that defines the operating system interface that 2516** the new database connection should use. ^If the fourth parameter is 2517** a NULL pointer then the default [sqlite3_vfs] object is used. 2518** 2519** ^If the filename is ":memory:", then a private, temporary in-memory database 2520** is created for the connection. ^This in-memory database will vanish when 2521** the database connection is closed. Future versions of SQLite might 2522** make use of additional special filenames that begin with the ":" character. 2523** It is recommended that when a database filename actually does begin with 2524** a ":" character you should prefix the filename with a pathname such as 2525** "./" to avoid ambiguity. 2526** 2527** ^If the filename is an empty string, then a private, temporary 2528** on-disk database will be created. ^This private database will be 2529** automatically deleted as soon as the database connection is closed. 2530** 2531** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2532** 2533** ^If [URI filename] interpretation is enabled, and the filename argument 2534** begins with "file:", then the filename is interpreted as a URI. ^URI 2535** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2536** set in the fourth argument to sqlite3_open_v2(), or if it has 2537** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2538** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2539** As of SQLite version 3.7.7, URI filename interpretation is turned off 2540** by default, but future releases of SQLite might enable URI filename 2541** interpretation by default. See "[URI filenames]" for additional 2542** information. 2543** 2544** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2545** authority, then it must be either an empty string or the string 2546** "localhost". ^If the authority is not an empty string or "localhost", an 2547** error is returned to the caller. ^The fragment component of a URI, if 2548** present, is ignored. 2549** 2550** ^SQLite uses the path component of the URI as the name of the disk file 2551** which contains the database. ^If the path begins with a '/' character, 2552** then it is interpreted as an absolute path. ^If the path does not begin 2553** with a '/' (meaning that the authority section is omitted from the URI) 2554** then the path is interpreted as a relative path. 2555** ^On windows, the first component of an absolute path 2556** is a drive specification (e.g. "C:"). 2557** 2558** [[core URI query parameters]] 2559** The query component of a URI may contain parameters that are interpreted 2560** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2561** SQLite interprets the following three query parameters: 2562** 2563** <ul> 2564** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2565** a VFS object that provides the operating system interface that should 2566** be used to access the database file on disk. ^If this option is set to 2567** an empty string the default VFS object is used. ^Specifying an unknown 2568** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2569** present, then the VFS specified by the option takes precedence over 2570** the value passed as the fourth parameter to sqlite3_open_v2(). 2571** 2572** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw" or 2573** "rwc". Attempting to set it to any other value is an error)^. 2574** ^If "ro" is specified, then the database is opened for read-only 2575** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2576** third argument to sqlite3_prepare_v2(). ^If the mode option is set to 2577** "rw", then the database is opened for read-write (but not create) 2578** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2579** been set. ^Value "rwc" is equivalent to setting both 2580** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If sqlite3_open_v2() is 2581** used, it is an error to specify a value for the mode parameter that is 2582** less restrictive than that specified by the flags passed as the third 2583** parameter. 2584** 2585** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2586** "private". ^Setting it to "shared" is equivalent to setting the 2587** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2588** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2589** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2590** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2591** a URI filename, its value overrides any behaviour requested by setting 2592** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2593** </ul> 2594** 2595** ^Specifying an unknown parameter in the query component of a URI is not an 2596** error. Future versions of SQLite might understand additional query 2597** parameters. See "[query parameters with special meaning to SQLite]" for 2598** additional information. 2599** 2600** [[URI filename examples]] <h3>URI filename examples</h3> 2601** 2602** <table border="1" align=center cellpadding=5> 2603** <tr><th> URI filenames <th> Results 2604** <tr><td> file:data.db <td> 2605** Open the file "data.db" in the current directory. 2606** <tr><td> file:/home/fred/data.db<br> 2607** file:///home/fred/data.db <br> 2608** file://localhost/home/fred/data.db <br> <td> 2609** Open the database file "/home/fred/data.db". 2610** <tr><td> file://darkstar/home/fred/data.db <td> 2611** An error. "darkstar" is not a recognized authority. 2612** <tr><td style="white-space:nowrap"> 2613** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2614** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2615** C:. Note that the %20 escaping in this example is not strictly 2616** necessary - space characters can be used literally 2617** in URI filenames. 2618** <tr><td> file:data.db?mode=ro&cache=private <td> 2619** Open file "data.db" in the current directory for read-only access. 2620** Regardless of whether or not shared-cache mode is enabled by 2621** default, use a private cache. 2622** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2623** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2624** <tr><td> file:data.db?mode=readonly <td> 2625** An error. "readonly" is not a valid option for the "mode" parameter. 2626** </table> 2627** 2628** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2629** query components of a URI. A hexadecimal escape sequence consists of a 2630** percent sign - "%" - followed by exactly two hexadecimal digits 2631** specifying an octet value. ^Before the path or query components of a 2632** URI filename are interpreted, they are encoded using UTF-8 and all 2633** hexadecimal escape sequences replaced by a single byte containing the 2634** corresponding octet. If this process generates an invalid UTF-8 encoding, 2635** the results are undefined. 2636** 2637** <b>Note to Windows users:</b> The encoding used for the filename argument 2638** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2639** codepage is currently defined. Filenames containing international 2640** characters must be converted to UTF-8 prior to passing them into 2641** sqlite3_open() or sqlite3_open_v2(). 2642*/ 2643int sqlite3_open( 2644 const char *filename, /* Database filename (UTF-8) */ 2645 sqlite3 **ppDb /* OUT: SQLite db handle */ 2646); 2647int sqlite3_open16( 2648 const void *filename, /* Database filename (UTF-16) */ 2649 sqlite3 **ppDb /* OUT: SQLite db handle */ 2650); 2651int sqlite3_open_v2( 2652 const char *filename, /* Database filename (UTF-8) */ 2653 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2654 int flags, /* Flags */ 2655 const char *zVfs /* Name of VFS module to use */ 2656); 2657 2658/* 2659** CAPI3REF: Obtain Values For URI Parameters 2660** 2661** These are utility routines, useful to VFS implementations, that check 2662** to see if a database file was a URI that contained a specific query 2663** parameter, and if so obtains the value of that query parameter. 2664** 2665** If F is the database filename pointer passed into the xOpen() method of 2666** a VFS implementation when the flags parameter to xOpen() has one or 2667** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2668** P is the name of the query parameter, then 2669** sqlite3_uri_parameter(F,P) returns the value of the P 2670** parameter if it exists or a NULL pointer if P does not appear as a 2671** query parameter on F. If P is a query parameter of F 2672** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2673** a pointer to an empty string. 2674** 2675** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2676** parameter and returns true (1) or false (0) according to the value 2677** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2678** value of query parameter P is one of "yes", "true", or "on" in any 2679** case or if the value begins with a non-zero number. The 2680** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2681** query parameter P is one of "no", "false", or "off" in any case or 2682** if the value begins with a numeric zero. If P is not a query 2683** parameter on F or if the value of P is does not match any of the 2684** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2685** 2686** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2687** 64-bit signed integer and returns that integer, or D if P does not 2688** exist. If the value of P is something other than an integer, then 2689** zero is returned. 2690** 2691** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2692** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2693** is not a database file pathname pointer that SQLite passed into the xOpen 2694** VFS method, then the behavior of this routine is undefined and probably 2695** undesirable. 2696*/ 2697const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2698int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2699sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2700 2701 2702/* 2703** CAPI3REF: Error Codes And Messages 2704** 2705** ^The sqlite3_errcode() interface returns the numeric [result code] or 2706** [extended result code] for the most recent failed sqlite3_* API call 2707** associated with a [database connection]. If a prior API call failed 2708** but the most recent API call succeeded, the return value from 2709** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2710** interface is the same except that it always returns the 2711** [extended result code] even when extended result codes are 2712** disabled. 2713** 2714** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2715** text that describes the error, as either UTF-8 or UTF-16 respectively. 2716** ^(Memory to hold the error message string is managed internally. 2717** The application does not need to worry about freeing the result. 2718** However, the error string might be overwritten or deallocated by 2719** subsequent calls to other SQLite interface functions.)^ 2720** 2721** When the serialized [threading mode] is in use, it might be the 2722** case that a second error occurs on a separate thread in between 2723** the time of the first error and the call to these interfaces. 2724** When that happens, the second error will be reported since these 2725** interfaces always report the most recent result. To avoid 2726** this, each thread can obtain exclusive use of the [database connection] D 2727** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2728** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2729** all calls to the interfaces listed here are completed. 2730** 2731** If an interface fails with SQLITE_MISUSE, that means the interface 2732** was invoked incorrectly by the application. In that case, the 2733** error code and message may or may not be set. 2734*/ 2735int sqlite3_errcode(sqlite3 *db); 2736int sqlite3_extended_errcode(sqlite3 *db); 2737const char *sqlite3_errmsg(sqlite3*); 2738const void *sqlite3_errmsg16(sqlite3*); 2739 2740/* 2741** CAPI3REF: SQL Statement Object 2742** KEYWORDS: {prepared statement} {prepared statements} 2743** 2744** An instance of this object represents a single SQL statement. 2745** This object is variously known as a "prepared statement" or a 2746** "compiled SQL statement" or simply as a "statement". 2747** 2748** The life of a statement object goes something like this: 2749** 2750** <ol> 2751** <li> Create the object using [sqlite3_prepare_v2()] or a related 2752** function. 2753** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2754** interfaces. 2755** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2756** <li> Reset the statement using [sqlite3_reset()] then go back 2757** to step 2. Do this zero or more times. 2758** <li> Destroy the object using [sqlite3_finalize()]. 2759** </ol> 2760** 2761** Refer to documentation on individual methods above for additional 2762** information. 2763*/ 2764typedef struct sqlite3_stmt sqlite3_stmt; 2765 2766/* 2767** CAPI3REF: Run-time Limits 2768** 2769** ^(This interface allows the size of various constructs to be limited 2770** on a connection by connection basis. The first parameter is the 2771** [database connection] whose limit is to be set or queried. The 2772** second parameter is one of the [limit categories] that define a 2773** class of constructs to be size limited. The third parameter is the 2774** new limit for that construct.)^ 2775** 2776** ^If the new limit is a negative number, the limit is unchanged. 2777** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2778** [limits | hard upper bound] 2779** set at compile-time by a C preprocessor macro called 2780** [limits | SQLITE_MAX_<i>NAME</i>]. 2781** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2782** ^Attempts to increase a limit above its hard upper bound are 2783** silently truncated to the hard upper bound. 2784** 2785** ^Regardless of whether or not the limit was changed, the 2786** [sqlite3_limit()] interface returns the prior value of the limit. 2787** ^Hence, to find the current value of a limit without changing it, 2788** simply invoke this interface with the third parameter set to -1. 2789** 2790** Run-time limits are intended for use in applications that manage 2791** both their own internal database and also databases that are controlled 2792** by untrusted external sources. An example application might be a 2793** web browser that has its own databases for storing history and 2794** separate databases controlled by JavaScript applications downloaded 2795** off the Internet. The internal databases can be given the 2796** large, default limits. Databases managed by external sources can 2797** be given much smaller limits designed to prevent a denial of service 2798** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2799** interface to further control untrusted SQL. The size of the database 2800** created by an untrusted script can be contained using the 2801** [max_page_count] [PRAGMA]. 2802** 2803** New run-time limit categories may be added in future releases. 2804*/ 2805int sqlite3_limit(sqlite3*, int id, int newVal); 2806 2807/* 2808** CAPI3REF: Run-Time Limit Categories 2809** KEYWORDS: {limit category} {*limit categories} 2810** 2811** These constants define various performance limits 2812** that can be lowered at run-time using [sqlite3_limit()]. 2813** The synopsis of the meanings of the various limits is shown below. 2814** Additional information is available at [limits | Limits in SQLite]. 2815** 2816** <dl> 2817** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2818** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2819** 2820** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2821** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2822** 2823** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2824** <dd>The maximum number of columns in a table definition or in the 2825** result set of a [SELECT] or the maximum number of columns in an index 2826** or in an ORDER BY or GROUP BY clause.</dd>)^ 2827** 2828** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2829** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2830** 2831** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2832** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2833** 2834** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2835** <dd>The maximum number of instructions in a virtual machine program 2836** used to implement an SQL statement. This limit is not currently 2837** enforced, though that might be added in some future release of 2838** SQLite.</dd>)^ 2839** 2840** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2841** <dd>The maximum number of arguments on a function.</dd>)^ 2842** 2843** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2844** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2845** 2846** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2847** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2848** <dd>The maximum length of the pattern argument to the [LIKE] or 2849** [GLOB] operators.</dd>)^ 2850** 2851** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2852** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2853** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2854** 2855** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2856** <dd>The maximum depth of recursion for triggers.</dd>)^ 2857** </dl> 2858*/ 2859#define SQLITE_LIMIT_LENGTH 0 2860#define SQLITE_LIMIT_SQL_LENGTH 1 2861#define SQLITE_LIMIT_COLUMN 2 2862#define SQLITE_LIMIT_EXPR_DEPTH 3 2863#define SQLITE_LIMIT_COMPOUND_SELECT 4 2864#define SQLITE_LIMIT_VDBE_OP 5 2865#define SQLITE_LIMIT_FUNCTION_ARG 6 2866#define SQLITE_LIMIT_ATTACHED 7 2867#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2868#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2869#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2870 2871/* 2872** CAPI3REF: Compiling An SQL Statement 2873** KEYWORDS: {SQL statement compiler} 2874** 2875** To execute an SQL query, it must first be compiled into a byte-code 2876** program using one of these routines. 2877** 2878** The first argument, "db", is a [database connection] obtained from a 2879** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2880** [sqlite3_open16()]. The database connection must not have been closed. 2881** 2882** The second argument, "zSql", is the statement to be compiled, encoded 2883** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2884** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2885** use UTF-16. 2886** 2887** ^If the nByte argument is less than zero, then zSql is read up to the 2888** first zero terminator. ^If nByte is non-negative, then it is the maximum 2889** number of bytes read from zSql. ^When nByte is non-negative, the 2890** zSql string ends at either the first '\000' or '\u0000' character or 2891** the nByte-th byte, whichever comes first. If the caller knows 2892** that the supplied string is nul-terminated, then there is a small 2893** performance advantage to be gained by passing an nByte parameter that 2894** is equal to the number of bytes in the input string <i>including</i> 2895** the nul-terminator bytes as this saves SQLite from having to 2896** make a copy of the input string. 2897** 2898** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2899** past the end of the first SQL statement in zSql. These routines only 2900** compile the first statement in zSql, so *pzTail is left pointing to 2901** what remains uncompiled. 2902** 2903** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2904** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2905** to NULL. ^If the input text contains no SQL (if the input is an empty 2906** string or a comment) then *ppStmt is set to NULL. 2907** The calling procedure is responsible for deleting the compiled 2908** SQL statement using [sqlite3_finalize()] after it has finished with it. 2909** ppStmt may not be NULL. 2910** 2911** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2912** otherwise an [error code] is returned. 2913** 2914** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2915** recommended for all new programs. The two older interfaces are retained 2916** for backwards compatibility, but their use is discouraged. 2917** ^In the "v2" interfaces, the prepared statement 2918** that is returned (the [sqlite3_stmt] object) contains a copy of the 2919** original SQL text. This causes the [sqlite3_step()] interface to 2920** behave differently in three ways: 2921** 2922** <ol> 2923** <li> 2924** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2925** always used to do, [sqlite3_step()] will automatically recompile the SQL 2926** statement and try to run it again. 2927** </li> 2928** 2929** <li> 2930** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2931** [error codes] or [extended error codes]. ^The legacy behavior was that 2932** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2933** and the application would have to make a second call to [sqlite3_reset()] 2934** in order to find the underlying cause of the problem. With the "v2" prepare 2935** interfaces, the underlying reason for the error is returned immediately. 2936** </li> 2937** 2938** <li> 2939** ^If the specific value bound to [parameter | host parameter] in the 2940** WHERE clause might influence the choice of query plan for a statement, 2941** then the statement will be automatically recompiled, as if there had been 2942** a schema change, on the first [sqlite3_step()] call following any change 2943** to the [sqlite3_bind_text | bindings] of that [parameter]. 2944** ^The specific value of WHERE-clause [parameter] might influence the 2945** choice of query plan if the parameter is the left-hand side of a [LIKE] 2946** or [GLOB] operator or if the parameter is compared to an indexed column 2947** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 2948** the 2949** </li> 2950** </ol> 2951*/ 2952int sqlite3_prepare( 2953 sqlite3 *db, /* Database handle */ 2954 const char *zSql, /* SQL statement, UTF-8 encoded */ 2955 int nByte, /* Maximum length of zSql in bytes. */ 2956 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2957 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2958); 2959int sqlite3_prepare_v2( 2960 sqlite3 *db, /* Database handle */ 2961 const char *zSql, /* SQL statement, UTF-8 encoded */ 2962 int nByte, /* Maximum length of zSql in bytes. */ 2963 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2964 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2965); 2966int sqlite3_prepare16( 2967 sqlite3 *db, /* Database handle */ 2968 const void *zSql, /* SQL statement, UTF-16 encoded */ 2969 int nByte, /* Maximum length of zSql in bytes. */ 2970 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2971 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2972); 2973int sqlite3_prepare16_v2( 2974 sqlite3 *db, /* Database handle */ 2975 const void *zSql, /* SQL statement, UTF-16 encoded */ 2976 int nByte, /* Maximum length of zSql in bytes. */ 2977 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2978 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2979); 2980 2981/* 2982** CAPI3REF: Retrieving Statement SQL 2983** 2984** ^This interface can be used to retrieve a saved copy of the original 2985** SQL text used to create a [prepared statement] if that statement was 2986** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2987*/ 2988const char *sqlite3_sql(sqlite3_stmt *pStmt); 2989 2990/* 2991** CAPI3REF: Determine If An SQL Statement Writes The Database 2992** 2993** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 2994** and only if the [prepared statement] X makes no direct changes to 2995** the content of the database file. 2996** 2997** Note that [application-defined SQL functions] or 2998** [virtual tables] might change the database indirectly as a side effect. 2999** ^(For example, if an application defines a function "eval()" that 3000** calls [sqlite3_exec()], then the following SQL statement would 3001** change the database file through side-effects: 3002** 3003** <blockquote><pre> 3004** SELECT eval('DELETE FROM t1') FROM t2; 3005** </pre></blockquote> 3006** 3007** But because the [SELECT] statement does not change the database file 3008** directly, sqlite3_stmt_readonly() would still return true.)^ 3009** 3010** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3011** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3012** since the statements themselves do not actually modify the database but 3013** rather they control the timing of when other statements modify the 3014** database. ^The [ATTACH] and [DETACH] statements also cause 3015** sqlite3_stmt_readonly() to return true since, while those statements 3016** change the configuration of a database connection, they do not make 3017** changes to the content of the database files on disk. 3018*/ 3019int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3020 3021/* 3022** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3023** 3024** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3025** [prepared statement] S has been stepped at least once using 3026** [sqlite3_step(S)] but has not run to completion and/or has not 3027** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3028** interface returns false if S is a NULL pointer. If S is not a 3029** NULL pointer and is not a pointer to a valid [prepared statement] 3030** object, then the behavior is undefined and probably undesirable. 3031** 3032** This interface can be used in combination [sqlite3_next_stmt()] 3033** to locate all prepared statements associated with a database 3034** connection that are in need of being reset. This can be used, 3035** for example, in diagnostic routines to search for prepared 3036** statements that are holding a transaction open. 3037*/ 3038int sqlite3_stmt_busy(sqlite3_stmt*); 3039 3040/* 3041** CAPI3REF: Dynamically Typed Value Object 3042** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3043** 3044** SQLite uses the sqlite3_value object to represent all values 3045** that can be stored in a database table. SQLite uses dynamic typing 3046** for the values it stores. ^Values stored in sqlite3_value objects 3047** can be integers, floating point values, strings, BLOBs, or NULL. 3048** 3049** An sqlite3_value object may be either "protected" or "unprotected". 3050** Some interfaces require a protected sqlite3_value. Other interfaces 3051** will accept either a protected or an unprotected sqlite3_value. 3052** Every interface that accepts sqlite3_value arguments specifies 3053** whether or not it requires a protected sqlite3_value. 3054** 3055** The terms "protected" and "unprotected" refer to whether or not 3056** a mutex is held. An internal mutex is held for a protected 3057** sqlite3_value object but no mutex is held for an unprotected 3058** sqlite3_value object. If SQLite is compiled to be single-threaded 3059** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3060** or if SQLite is run in one of reduced mutex modes 3061** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3062** then there is no distinction between protected and unprotected 3063** sqlite3_value objects and they can be used interchangeably. However, 3064** for maximum code portability it is recommended that applications 3065** still make the distinction between protected and unprotected 3066** sqlite3_value objects even when not strictly required. 3067** 3068** ^The sqlite3_value objects that are passed as parameters into the 3069** implementation of [application-defined SQL functions] are protected. 3070** ^The sqlite3_value object returned by 3071** [sqlite3_column_value()] is unprotected. 3072** Unprotected sqlite3_value objects may only be used with 3073** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3074** The [sqlite3_value_blob | sqlite3_value_type()] family of 3075** interfaces require protected sqlite3_value objects. 3076*/ 3077typedef struct Mem sqlite3_value; 3078 3079/* 3080** CAPI3REF: SQL Function Context Object 3081** 3082** The context in which an SQL function executes is stored in an 3083** sqlite3_context object. ^A pointer to an sqlite3_context object 3084** is always first parameter to [application-defined SQL functions]. 3085** The application-defined SQL function implementation will pass this 3086** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3087** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3088** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3089** and/or [sqlite3_set_auxdata()]. 3090*/ 3091typedef struct sqlite3_context sqlite3_context; 3092 3093/* 3094** CAPI3REF: Binding Values To Prepared Statements 3095** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3096** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3097** 3098** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3099** literals may be replaced by a [parameter] that matches one of following 3100** templates: 3101** 3102** <ul> 3103** <li> ? 3104** <li> ?NNN 3105** <li> :VVV 3106** <li> @VVV 3107** <li> $VVV 3108** </ul> 3109** 3110** In the templates above, NNN represents an integer literal, 3111** and VVV represents an alphanumeric identifier.)^ ^The values of these 3112** parameters (also called "host parameter names" or "SQL parameters") 3113** can be set using the sqlite3_bind_*() routines defined here. 3114** 3115** ^The first argument to the sqlite3_bind_*() routines is always 3116** a pointer to the [sqlite3_stmt] object returned from 3117** [sqlite3_prepare_v2()] or its variants. 3118** 3119** ^The second argument is the index of the SQL parameter to be set. 3120** ^The leftmost SQL parameter has an index of 1. ^When the same named 3121** SQL parameter is used more than once, second and subsequent 3122** occurrences have the same index as the first occurrence. 3123** ^The index for named parameters can be looked up using the 3124** [sqlite3_bind_parameter_index()] API if desired. ^The index 3125** for "?NNN" parameters is the value of NNN. 3126** ^The NNN value must be between 1 and the [sqlite3_limit()] 3127** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3128** 3129** ^The third argument is the value to bind to the parameter. 3130** 3131** ^(In those routines that have a fourth argument, its value is the 3132** number of bytes in the parameter. To be clear: the value is the 3133** number of <u>bytes</u> in the value, not the number of characters.)^ 3134** ^If the fourth parameter is negative, the length of the string is 3135** the number of bytes up to the first zero terminator. 3136** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3137** or sqlite3_bind_text16() then that parameter must be the byte offset 3138** where the NUL terminator would occur assuming the string were NUL 3139** terminated. If any NUL characters occur at byte offsets less than 3140** the value of the fourth parameter then the resulting string value will 3141** contain embedded NULs. The result of expressions involving strings 3142** with embedded NULs is undefined. 3143** 3144** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3145** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3146** string after SQLite has finished with it. ^The destructor is called 3147** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3148** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3149** ^If the fifth argument is 3150** the special value [SQLITE_STATIC], then SQLite assumes that the 3151** information is in static, unmanaged space and does not need to be freed. 3152** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3153** SQLite makes its own private copy of the data immediately, before 3154** the sqlite3_bind_*() routine returns. 3155** 3156** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3157** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3158** (just an integer to hold its size) while it is being processed. 3159** Zeroblobs are intended to serve as placeholders for BLOBs whose 3160** content is later written using 3161** [sqlite3_blob_open | incremental BLOB I/O] routines. 3162** ^A negative value for the zeroblob results in a zero-length BLOB. 3163** 3164** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3165** for the [prepared statement] or with a prepared statement for which 3166** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3167** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3168** routine is passed a [prepared statement] that has been finalized, the 3169** result is undefined and probably harmful. 3170** 3171** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3172** ^Unbound parameters are interpreted as NULL. 3173** 3174** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3175** [error code] if anything goes wrong. 3176** ^[SQLITE_RANGE] is returned if the parameter 3177** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3178** 3179** See also: [sqlite3_bind_parameter_count()], 3180** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3181*/ 3182int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3183int sqlite3_bind_double(sqlite3_stmt*, int, double); 3184int sqlite3_bind_int(sqlite3_stmt*, int, int); 3185int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3186int sqlite3_bind_null(sqlite3_stmt*, int); 3187int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3188int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3189int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3190int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3191 3192/* 3193** CAPI3REF: Number Of SQL Parameters 3194** 3195** ^This routine can be used to find the number of [SQL parameters] 3196** in a [prepared statement]. SQL parameters are tokens of the 3197** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3198** placeholders for values that are [sqlite3_bind_blob | bound] 3199** to the parameters at a later time. 3200** 3201** ^(This routine actually returns the index of the largest (rightmost) 3202** parameter. For all forms except ?NNN, this will correspond to the 3203** number of unique parameters. If parameters of the ?NNN form are used, 3204** there may be gaps in the list.)^ 3205** 3206** See also: [sqlite3_bind_blob|sqlite3_bind()], 3207** [sqlite3_bind_parameter_name()], and 3208** [sqlite3_bind_parameter_index()]. 3209*/ 3210int sqlite3_bind_parameter_count(sqlite3_stmt*); 3211 3212/* 3213** CAPI3REF: Name Of A Host Parameter 3214** 3215** ^The sqlite3_bind_parameter_name(P,N) interface returns 3216** the name of the N-th [SQL parameter] in the [prepared statement] P. 3217** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3218** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3219** respectively. 3220** In other words, the initial ":" or "$" or "@" or "?" 3221** is included as part of the name.)^ 3222** ^Parameters of the form "?" without a following integer have no name 3223** and are referred to as "nameless" or "anonymous parameters". 3224** 3225** ^The first host parameter has an index of 1, not 0. 3226** 3227** ^If the value N is out of range or if the N-th parameter is 3228** nameless, then NULL is returned. ^The returned string is 3229** always in UTF-8 encoding even if the named parameter was 3230** originally specified as UTF-16 in [sqlite3_prepare16()] or 3231** [sqlite3_prepare16_v2()]. 3232** 3233** See also: [sqlite3_bind_blob|sqlite3_bind()], 3234** [sqlite3_bind_parameter_count()], and 3235** [sqlite3_bind_parameter_index()]. 3236*/ 3237const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3238 3239/* 3240** CAPI3REF: Index Of A Parameter With A Given Name 3241** 3242** ^Return the index of an SQL parameter given its name. ^The 3243** index value returned is suitable for use as the second 3244** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3245** is returned if no matching parameter is found. ^The parameter 3246** name must be given in UTF-8 even if the original statement 3247** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3248** 3249** See also: [sqlite3_bind_blob|sqlite3_bind()], 3250** [sqlite3_bind_parameter_count()], and 3251** [sqlite3_bind_parameter_index()]. 3252*/ 3253int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3254 3255/* 3256** CAPI3REF: Reset All Bindings On A Prepared Statement 3257** 3258** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3259** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3260** ^Use this routine to reset all host parameters to NULL. 3261*/ 3262int sqlite3_clear_bindings(sqlite3_stmt*); 3263 3264/* 3265** CAPI3REF: Number Of Columns In A Result Set 3266** 3267** ^Return the number of columns in the result set returned by the 3268** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3269** statement that does not return data (for example an [UPDATE]). 3270** 3271** See also: [sqlite3_data_count()] 3272*/ 3273int sqlite3_column_count(sqlite3_stmt *pStmt); 3274 3275/* 3276** CAPI3REF: Column Names In A Result Set 3277** 3278** ^These routines return the name assigned to a particular column 3279** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3280** interface returns a pointer to a zero-terminated UTF-8 string 3281** and sqlite3_column_name16() returns a pointer to a zero-terminated 3282** UTF-16 string. ^The first parameter is the [prepared statement] 3283** that implements the [SELECT] statement. ^The second parameter is the 3284** column number. ^The leftmost column is number 0. 3285** 3286** ^The returned string pointer is valid until either the [prepared statement] 3287** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3288** reprepared by the first call to [sqlite3_step()] for a particular run 3289** or until the next call to 3290** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3291** 3292** ^If sqlite3_malloc() fails during the processing of either routine 3293** (for example during a conversion from UTF-8 to UTF-16) then a 3294** NULL pointer is returned. 3295** 3296** ^The name of a result column is the value of the "AS" clause for 3297** that column, if there is an AS clause. If there is no AS clause 3298** then the name of the column is unspecified and may change from 3299** one release of SQLite to the next. 3300*/ 3301const char *sqlite3_column_name(sqlite3_stmt*, int N); 3302const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3303 3304/* 3305** CAPI3REF: Source Of Data In A Query Result 3306** 3307** ^These routines provide a means to determine the database, table, and 3308** table column that is the origin of a particular result column in 3309** [SELECT] statement. 3310** ^The name of the database or table or column can be returned as 3311** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3312** the database name, the _table_ routines return the table name, and 3313** the origin_ routines return the column name. 3314** ^The returned string is valid until the [prepared statement] is destroyed 3315** using [sqlite3_finalize()] or until the statement is automatically 3316** reprepared by the first call to [sqlite3_step()] for a particular run 3317** or until the same information is requested 3318** again in a different encoding. 3319** 3320** ^The names returned are the original un-aliased names of the 3321** database, table, and column. 3322** 3323** ^The first argument to these interfaces is a [prepared statement]. 3324** ^These functions return information about the Nth result column returned by 3325** the statement, where N is the second function argument. 3326** ^The left-most column is column 0 for these routines. 3327** 3328** ^If the Nth column returned by the statement is an expression or 3329** subquery and is not a column value, then all of these functions return 3330** NULL. ^These routine might also return NULL if a memory allocation error 3331** occurs. ^Otherwise, they return the name of the attached database, table, 3332** or column that query result column was extracted from. 3333** 3334** ^As with all other SQLite APIs, those whose names end with "16" return 3335** UTF-16 encoded strings and the other functions return UTF-8. 3336** 3337** ^These APIs are only available if the library was compiled with the 3338** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3339** 3340** If two or more threads call one or more of these routines against the same 3341** prepared statement and column at the same time then the results are 3342** undefined. 3343** 3344** If two or more threads call one or more 3345** [sqlite3_column_database_name | column metadata interfaces] 3346** for the same [prepared statement] and result column 3347** at the same time then the results are undefined. 3348*/ 3349const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3350const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3351const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3352const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3353const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3354const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3355 3356/* 3357** CAPI3REF: Declared Datatype Of A Query Result 3358** 3359** ^(The first parameter is a [prepared statement]. 3360** If this statement is a [SELECT] statement and the Nth column of the 3361** returned result set of that [SELECT] is a table column (not an 3362** expression or subquery) then the declared type of the table 3363** column is returned.)^ ^If the Nth column of the result set is an 3364** expression or subquery, then a NULL pointer is returned. 3365** ^The returned string is always UTF-8 encoded. 3366** 3367** ^(For example, given the database schema: 3368** 3369** CREATE TABLE t1(c1 VARIANT); 3370** 3371** and the following statement to be compiled: 3372** 3373** SELECT c1 + 1, c1 FROM t1; 3374** 3375** this routine would return the string "VARIANT" for the second result 3376** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3377** 3378** ^SQLite uses dynamic run-time typing. ^So just because a column 3379** is declared to contain a particular type does not mean that the 3380** data stored in that column is of the declared type. SQLite is 3381** strongly typed, but the typing is dynamic not static. ^Type 3382** is associated with individual values, not with the containers 3383** used to hold those values. 3384*/ 3385const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3386const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3387 3388/* 3389** CAPI3REF: Evaluate An SQL Statement 3390** 3391** After a [prepared statement] has been prepared using either 3392** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3393** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3394** must be called one or more times to evaluate the statement. 3395** 3396** The details of the behavior of the sqlite3_step() interface depend 3397** on whether the statement was prepared using the newer "v2" interface 3398** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3399** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3400** new "v2" interface is recommended for new applications but the legacy 3401** interface will continue to be supported. 3402** 3403** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3404** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3405** ^With the "v2" interface, any of the other [result codes] or 3406** [extended result codes] might be returned as well. 3407** 3408** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3409** database locks it needs to do its job. ^If the statement is a [COMMIT] 3410** or occurs outside of an explicit transaction, then you can retry the 3411** statement. If the statement is not a [COMMIT] and occurs within an 3412** explicit transaction then you should rollback the transaction before 3413** continuing. 3414** 3415** ^[SQLITE_DONE] means that the statement has finished executing 3416** successfully. sqlite3_step() should not be called again on this virtual 3417** machine without first calling [sqlite3_reset()] to reset the virtual 3418** machine back to its initial state. 3419** 3420** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3421** is returned each time a new row of data is ready for processing by the 3422** caller. The values may be accessed using the [column access functions]. 3423** sqlite3_step() is called again to retrieve the next row of data. 3424** 3425** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3426** violation) has occurred. sqlite3_step() should not be called again on 3427** the VM. More information may be found by calling [sqlite3_errmsg()]. 3428** ^With the legacy interface, a more specific error code (for example, 3429** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3430** can be obtained by calling [sqlite3_reset()] on the 3431** [prepared statement]. ^In the "v2" interface, 3432** the more specific error code is returned directly by sqlite3_step(). 3433** 3434** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3435** Perhaps it was called on a [prepared statement] that has 3436** already been [sqlite3_finalize | finalized] or on one that had 3437** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3438** be the case that the same database connection is being used by two or 3439** more threads at the same moment in time. 3440** 3441** For all versions of SQLite up to and including 3.6.23.1, a call to 3442** [sqlite3_reset()] was required after sqlite3_step() returned anything 3443** other than [SQLITE_ROW] before any subsequent invocation of 3444** sqlite3_step(). Failure to reset the prepared statement using 3445** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3446** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3447** calling [sqlite3_reset()] automatically in this circumstance rather 3448** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3449** break because any application that ever receives an SQLITE_MISUSE error 3450** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3451** can be used to restore the legacy behavior. 3452** 3453** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3454** API always returns a generic error code, [SQLITE_ERROR], following any 3455** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3456** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3457** specific [error codes] that better describes the error. 3458** We admit that this is a goofy design. The problem has been fixed 3459** with the "v2" interface. If you prepare all of your SQL statements 3460** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3461** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3462** then the more specific [error codes] are returned directly 3463** by sqlite3_step(). The use of the "v2" interface is recommended. 3464*/ 3465int sqlite3_step(sqlite3_stmt*); 3466 3467/* 3468** CAPI3REF: Number of columns in a result set 3469** 3470** ^The sqlite3_data_count(P) interface returns the number of columns in the 3471** current row of the result set of [prepared statement] P. 3472** ^If prepared statement P does not have results ready to return 3473** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3474** interfaces) then sqlite3_data_count(P) returns 0. 3475** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3476** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3477** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3478** will return non-zero if previous call to [sqlite3_step](P) returned 3479** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3480** where it always returns zero since each step of that multi-step 3481** pragma returns 0 columns of data. 3482** 3483** See also: [sqlite3_column_count()] 3484*/ 3485int sqlite3_data_count(sqlite3_stmt *pStmt); 3486 3487/* 3488** CAPI3REF: Fundamental Datatypes 3489** KEYWORDS: SQLITE_TEXT 3490** 3491** ^(Every value in SQLite has one of five fundamental datatypes: 3492** 3493** <ul> 3494** <li> 64-bit signed integer 3495** <li> 64-bit IEEE floating point number 3496** <li> string 3497** <li> BLOB 3498** <li> NULL 3499** </ul>)^ 3500** 3501** These constants are codes for each of those types. 3502** 3503** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3504** for a completely different meaning. Software that links against both 3505** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3506** SQLITE_TEXT. 3507*/ 3508#define SQLITE_INTEGER 1 3509#define SQLITE_FLOAT 2 3510#define SQLITE_BLOB 4 3511#define SQLITE_NULL 5 3512#ifdef SQLITE_TEXT 3513# undef SQLITE_TEXT 3514#else 3515# define SQLITE_TEXT 3 3516#endif 3517#define SQLITE3_TEXT 3 3518 3519/* 3520** CAPI3REF: Result Values From A Query 3521** KEYWORDS: {column access functions} 3522** 3523** These routines form the "result set" interface. 3524** 3525** ^These routines return information about a single column of the current 3526** result row of a query. ^In every case the first argument is a pointer 3527** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3528** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3529** and the second argument is the index of the column for which information 3530** should be returned. ^The leftmost column of the result set has the index 0. 3531** ^The number of columns in the result can be determined using 3532** [sqlite3_column_count()]. 3533** 3534** If the SQL statement does not currently point to a valid row, or if the 3535** column index is out of range, the result is undefined. 3536** These routines may only be called when the most recent call to 3537** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3538** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3539** If any of these routines are called after [sqlite3_reset()] or 3540** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3541** something other than [SQLITE_ROW], the results are undefined. 3542** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3543** are called from a different thread while any of these routines 3544** are pending, then the results are undefined. 3545** 3546** ^The sqlite3_column_type() routine returns the 3547** [SQLITE_INTEGER | datatype code] for the initial data type 3548** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3549** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3550** returned by sqlite3_column_type() is only meaningful if no type 3551** conversions have occurred as described below. After a type conversion, 3552** the value returned by sqlite3_column_type() is undefined. Future 3553** versions of SQLite may change the behavior of sqlite3_column_type() 3554** following a type conversion. 3555** 3556** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3557** routine returns the number of bytes in that BLOB or string. 3558** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3559** the string to UTF-8 and then returns the number of bytes. 3560** ^If the result is a numeric value then sqlite3_column_bytes() uses 3561** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3562** the number of bytes in that string. 3563** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3564** 3565** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3566** routine returns the number of bytes in that BLOB or string. 3567** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3568** the string to UTF-16 and then returns the number of bytes. 3569** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3570** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3571** the number of bytes in that string. 3572** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3573** 3574** ^The values returned by [sqlite3_column_bytes()] and 3575** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3576** of the string. ^For clarity: the values returned by 3577** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3578** bytes in the string, not the number of characters. 3579** 3580** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3581** even empty strings, are always zero-terminated. ^The return 3582** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3583** 3584** ^The object returned by [sqlite3_column_value()] is an 3585** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3586** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3587** If the [unprotected sqlite3_value] object returned by 3588** [sqlite3_column_value()] is used in any other way, including calls 3589** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3590** or [sqlite3_value_bytes()], then the behavior is undefined. 3591** 3592** These routines attempt to convert the value where appropriate. ^For 3593** example, if the internal representation is FLOAT and a text result 3594** is requested, [sqlite3_snprintf()] is used internally to perform the 3595** conversion automatically. ^(The following table details the conversions 3596** that are applied: 3597** 3598** <blockquote> 3599** <table border="1"> 3600** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3601** 3602** <tr><td> NULL <td> INTEGER <td> Result is 0 3603** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3604** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3605** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3606** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3607** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3608** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3609** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3610** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3611** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3612** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3613** <tr><td> TEXT <td> FLOAT <td> Use atof() 3614** <tr><td> TEXT <td> BLOB <td> No change 3615** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3616** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3617** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3618** </table> 3619** </blockquote>)^ 3620** 3621** The table above makes reference to standard C library functions atoi() 3622** and atof(). SQLite does not really use these functions. It has its 3623** own equivalent internal routines. The atoi() and atof() names are 3624** used in the table for brevity and because they are familiar to most 3625** C programmers. 3626** 3627** Note that when type conversions occur, pointers returned by prior 3628** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3629** sqlite3_column_text16() may be invalidated. 3630** Type conversions and pointer invalidations might occur 3631** in the following cases: 3632** 3633** <ul> 3634** <li> The initial content is a BLOB and sqlite3_column_text() or 3635** sqlite3_column_text16() is called. A zero-terminator might 3636** need to be added to the string.</li> 3637** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3638** sqlite3_column_text16() is called. The content must be converted 3639** to UTF-16.</li> 3640** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3641** sqlite3_column_text() is called. The content must be converted 3642** to UTF-8.</li> 3643** </ul> 3644** 3645** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3646** not invalidate a prior pointer, though of course the content of the buffer 3647** that the prior pointer references will have been modified. Other kinds 3648** of conversion are done in place when it is possible, but sometimes they 3649** are not possible and in those cases prior pointers are invalidated. 3650** 3651** The safest and easiest to remember policy is to invoke these routines 3652** in one of the following ways: 3653** 3654** <ul> 3655** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3656** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3657** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3658** </ul> 3659** 3660** In other words, you should call sqlite3_column_text(), 3661** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3662** into the desired format, then invoke sqlite3_column_bytes() or 3663** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3664** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3665** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3666** with calls to sqlite3_column_bytes(). 3667** 3668** ^The pointers returned are valid until a type conversion occurs as 3669** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3670** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3671** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3672** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3673** [sqlite3_free()]. 3674** 3675** ^(If a memory allocation error occurs during the evaluation of any 3676** of these routines, a default value is returned. The default value 3677** is either the integer 0, the floating point number 0.0, or a NULL 3678** pointer. Subsequent calls to [sqlite3_errcode()] will return 3679** [SQLITE_NOMEM].)^ 3680*/ 3681const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3682int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3683int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3684double sqlite3_column_double(sqlite3_stmt*, int iCol); 3685int sqlite3_column_int(sqlite3_stmt*, int iCol); 3686sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3687const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3688const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3689int sqlite3_column_type(sqlite3_stmt*, int iCol); 3690sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3691 3692/* 3693** CAPI3REF: Destroy A Prepared Statement Object 3694** 3695** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3696** ^If the most recent evaluation of the statement encountered no errors 3697** or if the statement is never been evaluated, then sqlite3_finalize() returns 3698** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3699** sqlite3_finalize(S) returns the appropriate [error code] or 3700** [extended error code]. 3701** 3702** ^The sqlite3_finalize(S) routine can be called at any point during 3703** the life cycle of [prepared statement] S: 3704** before statement S is ever evaluated, after 3705** one or more calls to [sqlite3_reset()], or after any call 3706** to [sqlite3_step()] regardless of whether or not the statement has 3707** completed execution. 3708** 3709** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3710** 3711** The application must finalize every [prepared statement] in order to avoid 3712** resource leaks. It is a grievous error for the application to try to use 3713** a prepared statement after it has been finalized. Any use of a prepared 3714** statement after it has been finalized can result in undefined and 3715** undesirable behavior such as segfaults and heap corruption. 3716*/ 3717int sqlite3_finalize(sqlite3_stmt *pStmt); 3718 3719/* 3720** CAPI3REF: Reset A Prepared Statement Object 3721** 3722** The sqlite3_reset() function is called to reset a [prepared statement] 3723** object back to its initial state, ready to be re-executed. 3724** ^Any SQL statement variables that had values bound to them using 3725** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3726** Use [sqlite3_clear_bindings()] to reset the bindings. 3727** 3728** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3729** back to the beginning of its program. 3730** 3731** ^If the most recent call to [sqlite3_step(S)] for the 3732** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3733** or if [sqlite3_step(S)] has never before been called on S, 3734** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3735** 3736** ^If the most recent call to [sqlite3_step(S)] for the 3737** [prepared statement] S indicated an error, then 3738** [sqlite3_reset(S)] returns an appropriate [error code]. 3739** 3740** ^The [sqlite3_reset(S)] interface does not change the values 3741** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3742*/ 3743int sqlite3_reset(sqlite3_stmt *pStmt); 3744 3745/* 3746** CAPI3REF: Create Or Redefine SQL Functions 3747** KEYWORDS: {function creation routines} 3748** KEYWORDS: {application-defined SQL function} 3749** KEYWORDS: {application-defined SQL functions} 3750** 3751** ^These functions (collectively known as "function creation routines") 3752** are used to add SQL functions or aggregates or to redefine the behavior 3753** of existing SQL functions or aggregates. The only differences between 3754** these routines are the text encoding expected for 3755** the second parameter (the name of the function being created) 3756** and the presence or absence of a destructor callback for 3757** the application data pointer. 3758** 3759** ^The first parameter is the [database connection] to which the SQL 3760** function is to be added. ^If an application uses more than one database 3761** connection then application-defined SQL functions must be added 3762** to each database connection separately. 3763** 3764** ^The second parameter is the name of the SQL function to be created or 3765** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3766** representation, exclusive of the zero-terminator. ^Note that the name 3767** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3768** ^Any attempt to create a function with a longer name 3769** will result in [SQLITE_MISUSE] being returned. 3770** 3771** ^The third parameter (nArg) 3772** is the number of arguments that the SQL function or 3773** aggregate takes. ^If this parameter is -1, then the SQL function or 3774** aggregate may take any number of arguments between 0 and the limit 3775** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3776** parameter is less than -1 or greater than 127 then the behavior is 3777** undefined. 3778** 3779** ^The fourth parameter, eTextRep, specifies what 3780** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3781** its parameters. Every SQL function implementation must be able to work 3782** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3783** more efficient with one encoding than another. ^An application may 3784** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3785** times with the same function but with different values of eTextRep. 3786** ^When multiple implementations of the same function are available, SQLite 3787** will pick the one that involves the least amount of data conversion. 3788** If there is only a single implementation which does not care what text 3789** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3790** 3791** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3792** function can gain access to this pointer using [sqlite3_user_data()].)^ 3793** 3794** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3795** pointers to C-language functions that implement the SQL function or 3796** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3797** callback only; NULL pointers must be passed as the xStep and xFinal 3798** parameters. ^An aggregate SQL function requires an implementation of xStep 3799** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3800** SQL function or aggregate, pass NULL pointers for all three function 3801** callbacks. 3802** 3803** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3804** then it is destructor for the application data pointer. 3805** The destructor is invoked when the function is deleted, either by being 3806** overloaded or when the database connection closes.)^ 3807** ^The destructor is also invoked if the call to 3808** sqlite3_create_function_v2() fails. 3809** ^When the destructor callback of the tenth parameter is invoked, it 3810** is passed a single argument which is a copy of the application data 3811** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3812** 3813** ^It is permitted to register multiple implementations of the same 3814** functions with the same name but with either differing numbers of 3815** arguments or differing preferred text encodings. ^SQLite will use 3816** the implementation that most closely matches the way in which the 3817** SQL function is used. ^A function implementation with a non-negative 3818** nArg parameter is a better match than a function implementation with 3819** a negative nArg. ^A function where the preferred text encoding 3820** matches the database encoding is a better 3821** match than a function where the encoding is different. 3822** ^A function where the encoding difference is between UTF16le and UTF16be 3823** is a closer match than a function where the encoding difference is 3824** between UTF8 and UTF16. 3825** 3826** ^Built-in functions may be overloaded by new application-defined functions. 3827** 3828** ^An application-defined function is permitted to call other 3829** SQLite interfaces. However, such calls must not 3830** close the database connection nor finalize or reset the prepared 3831** statement in which the function is running. 3832*/ 3833int sqlite3_create_function( 3834 sqlite3 *db, 3835 const char *zFunctionName, 3836 int nArg, 3837 int eTextRep, 3838 void *pApp, 3839 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3840 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3841 void (*xFinal)(sqlite3_context*) 3842); 3843int sqlite3_create_function16( 3844 sqlite3 *db, 3845 const void *zFunctionName, 3846 int nArg, 3847 int eTextRep, 3848 void *pApp, 3849 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3850 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3851 void (*xFinal)(sqlite3_context*) 3852); 3853int sqlite3_create_function_v2( 3854 sqlite3 *db, 3855 const char *zFunctionName, 3856 int nArg, 3857 int eTextRep, 3858 void *pApp, 3859 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3860 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3861 void (*xFinal)(sqlite3_context*), 3862 void(*xDestroy)(void*) 3863); 3864 3865/* 3866** CAPI3REF: Text Encodings 3867** 3868** These constant define integer codes that represent the various 3869** text encodings supported by SQLite. 3870*/ 3871#define SQLITE_UTF8 1 3872#define SQLITE_UTF16LE 2 3873#define SQLITE_UTF16BE 3 3874#define SQLITE_UTF16 4 /* Use native byte order */ 3875#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3876#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3877 3878/* 3879** CAPI3REF: Deprecated Functions 3880** DEPRECATED 3881** 3882** These functions are [deprecated]. In order to maintain 3883** backwards compatibility with older code, these functions continue 3884** to be supported. However, new applications should avoid 3885** the use of these functions. To help encourage people to avoid 3886** using these functions, we are not going to tell you what they do. 3887*/ 3888#ifndef SQLITE_OMIT_DEPRECATED 3889SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3890SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3891SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3892SQLITE_DEPRECATED int sqlite3_global_recover(void); 3893SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3894SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3895#endif 3896 3897/* 3898** CAPI3REF: Obtaining SQL Function Parameter Values 3899** 3900** The C-language implementation of SQL functions and aggregates uses 3901** this set of interface routines to access the parameter values on 3902** the function or aggregate. 3903** 3904** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3905** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3906** define callbacks that implement the SQL functions and aggregates. 3907** The 3rd parameter to these callbacks is an array of pointers to 3908** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3909** each parameter to the SQL function. These routines are used to 3910** extract values from the [sqlite3_value] objects. 3911** 3912** These routines work only with [protected sqlite3_value] objects. 3913** Any attempt to use these routines on an [unprotected sqlite3_value] 3914** object results in undefined behavior. 3915** 3916** ^These routines work just like the corresponding [column access functions] 3917** except that these routines take a single [protected sqlite3_value] object 3918** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3919** 3920** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3921** in the native byte-order of the host machine. ^The 3922** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3923** extract UTF-16 strings as big-endian and little-endian respectively. 3924** 3925** ^(The sqlite3_value_numeric_type() interface attempts to apply 3926** numeric affinity to the value. This means that an attempt is 3927** made to convert the value to an integer or floating point. If 3928** such a conversion is possible without loss of information (in other 3929** words, if the value is a string that looks like a number) 3930** then the conversion is performed. Otherwise no conversion occurs. 3931** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3932** 3933** Please pay particular attention to the fact that the pointer returned 3934** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3935** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3936** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3937** or [sqlite3_value_text16()]. 3938** 3939** These routines must be called from the same thread as 3940** the SQL function that supplied the [sqlite3_value*] parameters. 3941*/ 3942const void *sqlite3_value_blob(sqlite3_value*); 3943int sqlite3_value_bytes(sqlite3_value*); 3944int sqlite3_value_bytes16(sqlite3_value*); 3945double sqlite3_value_double(sqlite3_value*); 3946int sqlite3_value_int(sqlite3_value*); 3947sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3948const unsigned char *sqlite3_value_text(sqlite3_value*); 3949const void *sqlite3_value_text16(sqlite3_value*); 3950const void *sqlite3_value_text16le(sqlite3_value*); 3951const void *sqlite3_value_text16be(sqlite3_value*); 3952int sqlite3_value_type(sqlite3_value*); 3953int sqlite3_value_numeric_type(sqlite3_value*); 3954 3955/* 3956** CAPI3REF: Obtain Aggregate Function Context 3957** 3958** Implementations of aggregate SQL functions use this 3959** routine to allocate memory for storing their state. 3960** 3961** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3962** for a particular aggregate function, SQLite 3963** allocates N of memory, zeroes out that memory, and returns a pointer 3964** to the new memory. ^On second and subsequent calls to 3965** sqlite3_aggregate_context() for the same aggregate function instance, 3966** the same buffer is returned. Sqlite3_aggregate_context() is normally 3967** called once for each invocation of the xStep callback and then one 3968** last time when the xFinal callback is invoked. ^(When no rows match 3969** an aggregate query, the xStep() callback of the aggregate function 3970** implementation is never called and xFinal() is called exactly once. 3971** In those cases, sqlite3_aggregate_context() might be called for the 3972** first time from within xFinal().)^ 3973** 3974** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3975** less than or equal to zero or if a memory allocate error occurs. 3976** 3977** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3978** determined by the N parameter on first successful call. Changing the 3979** value of N in subsequent call to sqlite3_aggregate_context() within 3980** the same aggregate function instance will not resize the memory 3981** allocation.)^ 3982** 3983** ^SQLite automatically frees the memory allocated by 3984** sqlite3_aggregate_context() when the aggregate query concludes. 3985** 3986** The first parameter must be a copy of the 3987** [sqlite3_context | SQL function context] that is the first parameter 3988** to the xStep or xFinal callback routine that implements the aggregate 3989** function. 3990** 3991** This routine must be called from the same thread in which 3992** the aggregate SQL function is running. 3993*/ 3994void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3995 3996/* 3997** CAPI3REF: User Data For Functions 3998** 3999** ^The sqlite3_user_data() interface returns a copy of 4000** the pointer that was the pUserData parameter (the 5th parameter) 4001** of the [sqlite3_create_function()] 4002** and [sqlite3_create_function16()] routines that originally 4003** registered the application defined function. 4004** 4005** This routine must be called from the same thread in which 4006** the application-defined function is running. 4007*/ 4008void *sqlite3_user_data(sqlite3_context*); 4009 4010/* 4011** CAPI3REF: Database Connection For Functions 4012** 4013** ^The sqlite3_context_db_handle() interface returns a copy of 4014** the pointer to the [database connection] (the 1st parameter) 4015** of the [sqlite3_create_function()] 4016** and [sqlite3_create_function16()] routines that originally 4017** registered the application defined function. 4018*/ 4019sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4020 4021/* 4022** CAPI3REF: Function Auxiliary Data 4023** 4024** The following two functions may be used by scalar SQL functions to 4025** associate metadata with argument values. If the same value is passed to 4026** multiple invocations of the same SQL function during query execution, under 4027** some circumstances the associated metadata may be preserved. This may 4028** be used, for example, to add a regular-expression matching scalar 4029** function. The compiled version of the regular expression is stored as 4030** metadata associated with the SQL value passed as the regular expression 4031** pattern. The compiled regular expression can be reused on multiple 4032** invocations of the same function so that the original pattern string 4033** does not need to be recompiled on each invocation. 4034** 4035** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4036** associated by the sqlite3_set_auxdata() function with the Nth argument 4037** value to the application-defined function. ^If no metadata has been ever 4038** been set for the Nth argument of the function, or if the corresponding 4039** function parameter has changed since the meta-data was set, 4040** then sqlite3_get_auxdata() returns a NULL pointer. 4041** 4042** ^The sqlite3_set_auxdata() interface saves the metadata 4043** pointed to by its 3rd parameter as the metadata for the N-th 4044** argument of the application-defined function. Subsequent 4045** calls to sqlite3_get_auxdata() might return this data, if it has 4046** not been destroyed. 4047** ^If it is not NULL, SQLite will invoke the destructor 4048** function given by the 4th parameter to sqlite3_set_auxdata() on 4049** the metadata when the corresponding function parameter changes 4050** or when the SQL statement completes, whichever comes first. 4051** 4052** SQLite is free to call the destructor and drop metadata on any 4053** parameter of any function at any time. ^The only guarantee is that 4054** the destructor will be called before the metadata is dropped. 4055** 4056** ^(In practice, metadata is preserved between function calls for 4057** expressions that are constant at compile time. This includes literal 4058** values and [parameters].)^ 4059** 4060** These routines must be called from the same thread in which 4061** the SQL function is running. 4062*/ 4063void *sqlite3_get_auxdata(sqlite3_context*, int N); 4064void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4065 4066 4067/* 4068** CAPI3REF: Constants Defining Special Destructor Behavior 4069** 4070** These are special values for the destructor that is passed in as the 4071** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4072** argument is SQLITE_STATIC, it means that the content pointer is constant 4073** and will never change. It does not need to be destroyed. ^The 4074** SQLITE_TRANSIENT value means that the content will likely change in 4075** the near future and that SQLite should make its own private copy of 4076** the content before returning. 4077** 4078** The typedef is necessary to work around problems in certain 4079** C++ compilers. See ticket #2191. 4080*/ 4081typedef void (*sqlite3_destructor_type)(void*); 4082#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4083#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4084 4085/* 4086** CAPI3REF: Setting The Result Of An SQL Function 4087** 4088** These routines are used by the xFunc or xFinal callbacks that 4089** implement SQL functions and aggregates. See 4090** [sqlite3_create_function()] and [sqlite3_create_function16()] 4091** for additional information. 4092** 4093** These functions work very much like the [parameter binding] family of 4094** functions used to bind values to host parameters in prepared statements. 4095** Refer to the [SQL parameter] documentation for additional information. 4096** 4097** ^The sqlite3_result_blob() interface sets the result from 4098** an application-defined function to be the BLOB whose content is pointed 4099** to by the second parameter and which is N bytes long where N is the 4100** third parameter. 4101** 4102** ^The sqlite3_result_zeroblob() interfaces set the result of 4103** the application-defined function to be a BLOB containing all zero 4104** bytes and N bytes in size, where N is the value of the 2nd parameter. 4105** 4106** ^The sqlite3_result_double() interface sets the result from 4107** an application-defined function to be a floating point value specified 4108** by its 2nd argument. 4109** 4110** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4111** cause the implemented SQL function to throw an exception. 4112** ^SQLite uses the string pointed to by the 4113** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4114** as the text of an error message. ^SQLite interprets the error 4115** message string from sqlite3_result_error() as UTF-8. ^SQLite 4116** interprets the string from sqlite3_result_error16() as UTF-16 in native 4117** byte order. ^If the third parameter to sqlite3_result_error() 4118** or sqlite3_result_error16() is negative then SQLite takes as the error 4119** message all text up through the first zero character. 4120** ^If the third parameter to sqlite3_result_error() or 4121** sqlite3_result_error16() is non-negative then SQLite takes that many 4122** bytes (not characters) from the 2nd parameter as the error message. 4123** ^The sqlite3_result_error() and sqlite3_result_error16() 4124** routines make a private copy of the error message text before 4125** they return. Hence, the calling function can deallocate or 4126** modify the text after they return without harm. 4127** ^The sqlite3_result_error_code() function changes the error code 4128** returned by SQLite as a result of an error in a function. ^By default, 4129** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4130** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4131** 4132** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 4133** indicating that a string or BLOB is too long to represent. 4134** 4135** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 4136** indicating that a memory allocation failed. 4137** 4138** ^The sqlite3_result_int() interface sets the return value 4139** of the application-defined function to be the 32-bit signed integer 4140** value given in the 2nd argument. 4141** ^The sqlite3_result_int64() interface sets the return value 4142** of the application-defined function to be the 64-bit signed integer 4143** value given in the 2nd argument. 4144** 4145** ^The sqlite3_result_null() interface sets the return value 4146** of the application-defined function to be NULL. 4147** 4148** ^The sqlite3_result_text(), sqlite3_result_text16(), 4149** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4150** set the return value of the application-defined function to be 4151** a text string which is represented as UTF-8, UTF-16 native byte order, 4152** UTF-16 little endian, or UTF-16 big endian, respectively. 4153** ^SQLite takes the text result from the application from 4154** the 2nd parameter of the sqlite3_result_text* interfaces. 4155** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4156** is negative, then SQLite takes result text from the 2nd parameter 4157** through the first zero character. 4158** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4159** is non-negative, then as many bytes (not characters) of the text 4160** pointed to by the 2nd parameter are taken as the application-defined 4161** function result. If the 3rd parameter is non-negative, then it 4162** must be the byte offset into the string where the NUL terminator would 4163** appear if the string where NUL terminated. If any NUL characters occur 4164** in the string at a byte offset that is less than the value of the 3rd 4165** parameter, then the resulting string will contain embedded NULs and the 4166** result of expressions operating on strings with embedded NULs is undefined. 4167** ^If the 4th parameter to the sqlite3_result_text* interfaces 4168** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4169** function as the destructor on the text or BLOB result when it has 4170** finished using that result. 4171** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4172** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4173** assumes that the text or BLOB result is in constant space and does not 4174** copy the content of the parameter nor call a destructor on the content 4175** when it has finished using that result. 4176** ^If the 4th parameter to the sqlite3_result_text* interfaces 4177** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4178** then SQLite makes a copy of the result into space obtained from 4179** from [sqlite3_malloc()] before it returns. 4180** 4181** ^The sqlite3_result_value() interface sets the result of 4182** the application-defined function to be a copy the 4183** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4184** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4185** so that the [sqlite3_value] specified in the parameter may change or 4186** be deallocated after sqlite3_result_value() returns without harm. 4187** ^A [protected sqlite3_value] object may always be used where an 4188** [unprotected sqlite3_value] object is required, so either 4189** kind of [sqlite3_value] object can be used with this interface. 4190** 4191** If these routines are called from within the different thread 4192** than the one containing the application-defined function that received 4193** the [sqlite3_context] pointer, the results are undefined. 4194*/ 4195void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4196void sqlite3_result_double(sqlite3_context*, double); 4197void sqlite3_result_error(sqlite3_context*, const char*, int); 4198void sqlite3_result_error16(sqlite3_context*, const void*, int); 4199void sqlite3_result_error_toobig(sqlite3_context*); 4200void sqlite3_result_error_nomem(sqlite3_context*); 4201void sqlite3_result_error_code(sqlite3_context*, int); 4202void sqlite3_result_int(sqlite3_context*, int); 4203void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4204void sqlite3_result_null(sqlite3_context*); 4205void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4206void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4207void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4208void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4209void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4210void sqlite3_result_zeroblob(sqlite3_context*, int n); 4211 4212/* 4213** CAPI3REF: Define New Collating Sequences 4214** 4215** ^These functions add, remove, or modify a [collation] associated 4216** with the [database connection] specified as the first argument. 4217** 4218** ^The name of the collation is a UTF-8 string 4219** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4220** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4221** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4222** considered to be the same name. 4223** 4224** ^(The third argument (eTextRep) must be one of the constants: 4225** <ul> 4226** <li> [SQLITE_UTF8], 4227** <li> [SQLITE_UTF16LE], 4228** <li> [SQLITE_UTF16BE], 4229** <li> [SQLITE_UTF16], or 4230** <li> [SQLITE_UTF16_ALIGNED]. 4231** </ul>)^ 4232** ^The eTextRep argument determines the encoding of strings passed 4233** to the collating function callback, xCallback. 4234** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4235** force strings to be UTF16 with native byte order. 4236** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4237** on an even byte address. 4238** 4239** ^The fourth argument, pArg, is an application data pointer that is passed 4240** through as the first argument to the collating function callback. 4241** 4242** ^The fifth argument, xCallback, is a pointer to the collating function. 4243** ^Multiple collating functions can be registered using the same name but 4244** with different eTextRep parameters and SQLite will use whichever 4245** function requires the least amount of data transformation. 4246** ^If the xCallback argument is NULL then the collating function is 4247** deleted. ^When all collating functions having the same name are deleted, 4248** that collation is no longer usable. 4249** 4250** ^The collating function callback is invoked with a copy of the pArg 4251** application data pointer and with two strings in the encoding specified 4252** by the eTextRep argument. The collating function must return an 4253** integer that is negative, zero, or positive 4254** if the first string is less than, equal to, or greater than the second, 4255** respectively. A collating function must always return the same answer 4256** given the same inputs. If two or more collating functions are registered 4257** to the same collation name (using different eTextRep values) then all 4258** must give an equivalent answer when invoked with equivalent strings. 4259** The collating function must obey the following properties for all 4260** strings A, B, and C: 4261** 4262** <ol> 4263** <li> If A==B then B==A. 4264** <li> If A==B and B==C then A==C. 4265** <li> If A<B THEN B>A. 4266** <li> If A<B and B<C then A<C. 4267** </ol> 4268** 4269** If a collating function fails any of the above constraints and that 4270** collating function is registered and used, then the behavior of SQLite 4271** is undefined. 4272** 4273** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4274** with the addition that the xDestroy callback is invoked on pArg when 4275** the collating function is deleted. 4276** ^Collating functions are deleted when they are overridden by later 4277** calls to the collation creation functions or when the 4278** [database connection] is closed using [sqlite3_close()]. 4279** 4280** ^The xDestroy callback is <u>not</u> called if the 4281** sqlite3_create_collation_v2() function fails. Applications that invoke 4282** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4283** check the return code and dispose of the application data pointer 4284** themselves rather than expecting SQLite to deal with it for them. 4285** This is different from every other SQLite interface. The inconsistency 4286** is unfortunate but cannot be changed without breaking backwards 4287** compatibility. 4288** 4289** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4290*/ 4291int sqlite3_create_collation( 4292 sqlite3*, 4293 const char *zName, 4294 int eTextRep, 4295 void *pArg, 4296 int(*xCompare)(void*,int,const void*,int,const void*) 4297); 4298int sqlite3_create_collation_v2( 4299 sqlite3*, 4300 const char *zName, 4301 int eTextRep, 4302 void *pArg, 4303 int(*xCompare)(void*,int,const void*,int,const void*), 4304 void(*xDestroy)(void*) 4305); 4306int sqlite3_create_collation16( 4307 sqlite3*, 4308 const void *zName, 4309 int eTextRep, 4310 void *pArg, 4311 int(*xCompare)(void*,int,const void*,int,const void*) 4312); 4313 4314/* 4315** CAPI3REF: Collation Needed Callbacks 4316** 4317** ^To avoid having to register all collation sequences before a database 4318** can be used, a single callback function may be registered with the 4319** [database connection] to be invoked whenever an undefined collation 4320** sequence is required. 4321** 4322** ^If the function is registered using the sqlite3_collation_needed() API, 4323** then it is passed the names of undefined collation sequences as strings 4324** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4325** the names are passed as UTF-16 in machine native byte order. 4326** ^A call to either function replaces the existing collation-needed callback. 4327** 4328** ^(When the callback is invoked, the first argument passed is a copy 4329** of the second argument to sqlite3_collation_needed() or 4330** sqlite3_collation_needed16(). The second argument is the database 4331** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4332** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4333** sequence function required. The fourth parameter is the name of the 4334** required collation sequence.)^ 4335** 4336** The callback function should register the desired collation using 4337** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4338** [sqlite3_create_collation_v2()]. 4339*/ 4340int sqlite3_collation_needed( 4341 sqlite3*, 4342 void*, 4343 void(*)(void*,sqlite3*,int eTextRep,const char*) 4344); 4345int sqlite3_collation_needed16( 4346 sqlite3*, 4347 void*, 4348 void(*)(void*,sqlite3*,int eTextRep,const void*) 4349); 4350 4351#ifdef SQLITE_HAS_CODEC 4352/* 4353** Specify the key for an encrypted database. This routine should be 4354** called right after sqlite3_open(). 4355** 4356** The code to implement this API is not available in the public release 4357** of SQLite. 4358*/ 4359int sqlite3_key( 4360 sqlite3 *db, /* Database to be rekeyed */ 4361 const void *pKey, int nKey /* The key */ 4362); 4363 4364/* 4365** Change the key on an open database. If the current database is not 4366** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4367** database is decrypted. 4368** 4369** The code to implement this API is not available in the public release 4370** of SQLite. 4371*/ 4372int sqlite3_rekey( 4373 sqlite3 *db, /* Database to be rekeyed */ 4374 const void *pKey, int nKey /* The new key */ 4375); 4376 4377/* 4378** Specify the activation key for a SEE database. Unless 4379** activated, none of the SEE routines will work. 4380*/ 4381void sqlite3_activate_see( 4382 const char *zPassPhrase /* Activation phrase */ 4383); 4384#endif 4385 4386#ifdef SQLITE_ENABLE_CEROD 4387/* 4388** Specify the activation key for a CEROD database. Unless 4389** activated, none of the CEROD routines will work. 4390*/ 4391void sqlite3_activate_cerod( 4392 const char *zPassPhrase /* Activation phrase */ 4393); 4394#endif 4395 4396/* 4397** CAPI3REF: Suspend Execution For A Short Time 4398** 4399** The sqlite3_sleep() function causes the current thread to suspend execution 4400** for at least a number of milliseconds specified in its parameter. 4401** 4402** If the operating system does not support sleep requests with 4403** millisecond time resolution, then the time will be rounded up to 4404** the nearest second. The number of milliseconds of sleep actually 4405** requested from the operating system is returned. 4406** 4407** ^SQLite implements this interface by calling the xSleep() 4408** method of the default [sqlite3_vfs] object. If the xSleep() method 4409** of the default VFS is not implemented correctly, or not implemented at 4410** all, then the behavior of sqlite3_sleep() may deviate from the description 4411** in the previous paragraphs. 4412*/ 4413int sqlite3_sleep(int); 4414 4415/* 4416** CAPI3REF: Name Of The Folder Holding Temporary Files 4417** 4418** ^(If this global variable is made to point to a string which is 4419** the name of a folder (a.k.a. directory), then all temporary files 4420** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4421** will be placed in that directory.)^ ^If this variable 4422** is a NULL pointer, then SQLite performs a search for an appropriate 4423** temporary file directory. 4424** 4425** It is not safe to read or modify this variable in more than one 4426** thread at a time. It is not safe to read or modify this variable 4427** if a [database connection] is being used at the same time in a separate 4428** thread. 4429** It is intended that this variable be set once 4430** as part of process initialization and before any SQLite interface 4431** routines have been called and that this variable remain unchanged 4432** thereafter. 4433** 4434** ^The [temp_store_directory pragma] may modify this variable and cause 4435** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4436** the [temp_store_directory pragma] always assumes that any string 4437** that this variable points to is held in memory obtained from 4438** [sqlite3_malloc] and the pragma may attempt to free that memory 4439** using [sqlite3_free]. 4440** Hence, if this variable is modified directly, either it should be 4441** made NULL or made to point to memory obtained from [sqlite3_malloc] 4442** or else the use of the [temp_store_directory pragma] should be avoided. 4443*/ 4444SQLITE_EXTERN char *sqlite3_temp_directory; 4445 4446/* 4447** CAPI3REF: Test For Auto-Commit Mode 4448** KEYWORDS: {autocommit mode} 4449** 4450** ^The sqlite3_get_autocommit() interface returns non-zero or 4451** zero if the given database connection is or is not in autocommit mode, 4452** respectively. ^Autocommit mode is on by default. 4453** ^Autocommit mode is disabled by a [BEGIN] statement. 4454** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4455** 4456** If certain kinds of errors occur on a statement within a multi-statement 4457** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4458** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4459** transaction might be rolled back automatically. The only way to 4460** find out whether SQLite automatically rolled back the transaction after 4461** an error is to use this function. 4462** 4463** If another thread changes the autocommit status of the database 4464** connection while this routine is running, then the return value 4465** is undefined. 4466*/ 4467int sqlite3_get_autocommit(sqlite3*); 4468 4469/* 4470** CAPI3REF: Find The Database Handle Of A Prepared Statement 4471** 4472** ^The sqlite3_db_handle interface returns the [database connection] handle 4473** to which a [prepared statement] belongs. ^The [database connection] 4474** returned by sqlite3_db_handle is the same [database connection] 4475** that was the first argument 4476** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4477** create the statement in the first place. 4478*/ 4479sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4480 4481/* 4482** CAPI3REF: Return The Filename For A Database Connection 4483** 4484** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4485** associated with database N of connection D. ^The main database file 4486** has the name "main". If there is no attached database N on the database 4487** connection D, or if database N is a temporary or in-memory database, then 4488** a NULL pointer is returned. 4489** 4490** ^The filename returned by this function is the output of the 4491** xFullPathname method of the [VFS]. ^In other words, the filename 4492** will be an absolute pathname, even if the filename used 4493** to open the database originally was a URI or relative pathname. 4494*/ 4495const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4496 4497/* 4498** CAPI3REF: Determine if a database is read-only 4499** 4500** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4501** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4502** the name of a database on connection D. 4503*/ 4504int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4505 4506/* 4507** CAPI3REF: Find the next prepared statement 4508** 4509** ^This interface returns a pointer to the next [prepared statement] after 4510** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4511** then this interface returns a pointer to the first prepared statement 4512** associated with the database connection pDb. ^If no prepared statement 4513** satisfies the conditions of this routine, it returns NULL. 4514** 4515** The [database connection] pointer D in a call to 4516** [sqlite3_next_stmt(D,S)] must refer to an open database 4517** connection and in particular must not be a NULL pointer. 4518*/ 4519sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4520 4521/* 4522** CAPI3REF: Commit And Rollback Notification Callbacks 4523** 4524** ^The sqlite3_commit_hook() interface registers a callback 4525** function to be invoked whenever a transaction is [COMMIT | committed]. 4526** ^Any callback set by a previous call to sqlite3_commit_hook() 4527** for the same database connection is overridden. 4528** ^The sqlite3_rollback_hook() interface registers a callback 4529** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4530** ^Any callback set by a previous call to sqlite3_rollback_hook() 4531** for the same database connection is overridden. 4532** ^The pArg argument is passed through to the callback. 4533** ^If the callback on a commit hook function returns non-zero, 4534** then the commit is converted into a rollback. 4535** 4536** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4537** return the P argument from the previous call of the same function 4538** on the same [database connection] D, or NULL for 4539** the first call for each function on D. 4540** 4541** The commit and rollback hook callbacks are not reentrant. 4542** The callback implementation must not do anything that will modify 4543** the database connection that invoked the callback. Any actions 4544** to modify the database connection must be deferred until after the 4545** completion of the [sqlite3_step()] call that triggered the commit 4546** or rollback hook in the first place. 4547** Note that running any other SQL statements, including SELECT statements, 4548** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4549** the database connections for the meaning of "modify" in this paragraph. 4550** 4551** ^Registering a NULL function disables the callback. 4552** 4553** ^When the commit hook callback routine returns zero, the [COMMIT] 4554** operation is allowed to continue normally. ^If the commit hook 4555** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4556** ^The rollback hook is invoked on a rollback that results from a commit 4557** hook returning non-zero, just as it would be with any other rollback. 4558** 4559** ^For the purposes of this API, a transaction is said to have been 4560** rolled back if an explicit "ROLLBACK" statement is executed, or 4561** an error or constraint causes an implicit rollback to occur. 4562** ^The rollback callback is not invoked if a transaction is 4563** automatically rolled back because the database connection is closed. 4564** 4565** See also the [sqlite3_update_hook()] interface. 4566*/ 4567void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4568void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4569 4570/* 4571** CAPI3REF: Data Change Notification Callbacks 4572** 4573** ^The sqlite3_update_hook() interface registers a callback function 4574** with the [database connection] identified by the first argument 4575** to be invoked whenever a row is updated, inserted or deleted. 4576** ^Any callback set by a previous call to this function 4577** for the same database connection is overridden. 4578** 4579** ^The second argument is a pointer to the function to invoke when a 4580** row is updated, inserted or deleted. 4581** ^The first argument to the callback is a copy of the third argument 4582** to sqlite3_update_hook(). 4583** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4584** or [SQLITE_UPDATE], depending on the operation that caused the callback 4585** to be invoked. 4586** ^The third and fourth arguments to the callback contain pointers to the 4587** database and table name containing the affected row. 4588** ^The final callback parameter is the [rowid] of the row. 4589** ^In the case of an update, this is the [rowid] after the update takes place. 4590** 4591** ^(The update hook is not invoked when internal system tables are 4592** modified (i.e. sqlite_master and sqlite_sequence).)^ 4593** 4594** ^In the current implementation, the update hook 4595** is not invoked when duplication rows are deleted because of an 4596** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4597** invoked when rows are deleted using the [truncate optimization]. 4598** The exceptions defined in this paragraph might change in a future 4599** release of SQLite. 4600** 4601** The update hook implementation must not do anything that will modify 4602** the database connection that invoked the update hook. Any actions 4603** to modify the database connection must be deferred until after the 4604** completion of the [sqlite3_step()] call that triggered the update hook. 4605** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4606** database connections for the meaning of "modify" in this paragraph. 4607** 4608** ^The sqlite3_update_hook(D,C,P) function 4609** returns the P argument from the previous call 4610** on the same [database connection] D, or NULL for 4611** the first call on D. 4612** 4613** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4614** interfaces. 4615*/ 4616void *sqlite3_update_hook( 4617 sqlite3*, 4618 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4619 void* 4620); 4621 4622/* 4623** CAPI3REF: Enable Or Disable Shared Pager Cache 4624** KEYWORDS: {shared cache} 4625** 4626** ^(This routine enables or disables the sharing of the database cache 4627** and schema data structures between [database connection | connections] 4628** to the same database. Sharing is enabled if the argument is true 4629** and disabled if the argument is false.)^ 4630** 4631** ^Cache sharing is enabled and disabled for an entire process. 4632** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4633** sharing was enabled or disabled for each thread separately. 4634** 4635** ^(The cache sharing mode set by this interface effects all subsequent 4636** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4637** Existing database connections continue use the sharing mode 4638** that was in effect at the time they were opened.)^ 4639** 4640** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4641** successfully. An [error code] is returned otherwise.)^ 4642** 4643** ^Shared cache is disabled by default. But this might change in 4644** future releases of SQLite. Applications that care about shared 4645** cache setting should set it explicitly. 4646** 4647** See Also: [SQLite Shared-Cache Mode] 4648*/ 4649int sqlite3_enable_shared_cache(int); 4650 4651/* 4652** CAPI3REF: Attempt To Free Heap Memory 4653** 4654** ^The sqlite3_release_memory() interface attempts to free N bytes 4655** of heap memory by deallocating non-essential memory allocations 4656** held by the database library. Memory used to cache database 4657** pages to improve performance is an example of non-essential memory. 4658** ^sqlite3_release_memory() returns the number of bytes actually freed, 4659** which might be more or less than the amount requested. 4660** ^The sqlite3_release_memory() routine is a no-op returning zero 4661** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4662** 4663** See also: [sqlite3_db_release_memory()] 4664*/ 4665int sqlite3_release_memory(int); 4666 4667/* 4668** CAPI3REF: Free Memory Used By A Database Connection 4669** 4670** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 4671** memory as possible from database connection D. Unlike the 4672** [sqlite3_release_memory()] interface, this interface is effect even 4673** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 4674** omitted. 4675** 4676** See also: [sqlite3_release_memory()] 4677*/ 4678int sqlite3_db_release_memory(sqlite3*); 4679 4680/* 4681** CAPI3REF: Impose A Limit On Heap Size 4682** 4683** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4684** soft limit on the amount of heap memory that may be allocated by SQLite. 4685** ^SQLite strives to keep heap memory utilization below the soft heap 4686** limit by reducing the number of pages held in the page cache 4687** as heap memory usages approaches the limit. 4688** ^The soft heap limit is "soft" because even though SQLite strives to stay 4689** below the limit, it will exceed the limit rather than generate 4690** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4691** is advisory only. 4692** 4693** ^The return value from sqlite3_soft_heap_limit64() is the size of 4694** the soft heap limit prior to the call, or negative in the case of an 4695** error. ^If the argument N is negative 4696** then no change is made to the soft heap limit. Hence, the current 4697** size of the soft heap limit can be determined by invoking 4698** sqlite3_soft_heap_limit64() with a negative argument. 4699** 4700** ^If the argument N is zero then the soft heap limit is disabled. 4701** 4702** ^(The soft heap limit is not enforced in the current implementation 4703** if one or more of following conditions are true: 4704** 4705** <ul> 4706** <li> The soft heap limit is set to zero. 4707** <li> Memory accounting is disabled using a combination of the 4708** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4709** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4710** <li> An alternative page cache implementation is specified using 4711** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 4712** <li> The page cache allocates from its own memory pool supplied 4713** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4714** from the heap. 4715** </ul>)^ 4716** 4717** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4718** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4719** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4720** the soft heap limit is enforced on every memory allocation. Without 4721** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4722** when memory is allocated by the page cache. Testing suggests that because 4723** the page cache is the predominate memory user in SQLite, most 4724** applications will achieve adequate soft heap limit enforcement without 4725** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4726** 4727** The circumstances under which SQLite will enforce the soft heap limit may 4728** changes in future releases of SQLite. 4729*/ 4730sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4731 4732/* 4733** CAPI3REF: Deprecated Soft Heap Limit Interface 4734** DEPRECATED 4735** 4736** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4737** interface. This routine is provided for historical compatibility 4738** only. All new applications should use the 4739** [sqlite3_soft_heap_limit64()] interface rather than this one. 4740*/ 4741SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4742 4743 4744/* 4745** CAPI3REF: Extract Metadata About A Column Of A Table 4746** 4747** ^This routine returns metadata about a specific column of a specific 4748** database table accessible using the [database connection] handle 4749** passed as the first function argument. 4750** 4751** ^The column is identified by the second, third and fourth parameters to 4752** this function. ^The second parameter is either the name of the database 4753** (i.e. "main", "temp", or an attached database) containing the specified 4754** table or NULL. ^If it is NULL, then all attached databases are searched 4755** for the table using the same algorithm used by the database engine to 4756** resolve unqualified table references. 4757** 4758** ^The third and fourth parameters to this function are the table and column 4759** name of the desired column, respectively. Neither of these parameters 4760** may be NULL. 4761** 4762** ^Metadata is returned by writing to the memory locations passed as the 5th 4763** and subsequent parameters to this function. ^Any of these arguments may be 4764** NULL, in which case the corresponding element of metadata is omitted. 4765** 4766** ^(<blockquote> 4767** <table border="1"> 4768** <tr><th> Parameter <th> Output<br>Type <th> Description 4769** 4770** <tr><td> 5th <td> const char* <td> Data type 4771** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4772** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4773** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4774** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4775** </table> 4776** </blockquote>)^ 4777** 4778** ^The memory pointed to by the character pointers returned for the 4779** declaration type and collation sequence is valid only until the next 4780** call to any SQLite API function. 4781** 4782** ^If the specified table is actually a view, an [error code] is returned. 4783** 4784** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4785** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4786** parameters are set for the explicitly declared column. ^(If there is no 4787** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4788** parameters are set as follows: 4789** 4790** <pre> 4791** data type: "INTEGER" 4792** collation sequence: "BINARY" 4793** not null: 0 4794** primary key: 1 4795** auto increment: 0 4796** </pre>)^ 4797** 4798** ^(This function may load one or more schemas from database files. If an 4799** error occurs during this process, or if the requested table or column 4800** cannot be found, an [error code] is returned and an error message left 4801** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4802** 4803** ^This API is only available if the library was compiled with the 4804** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4805*/ 4806int sqlite3_table_column_metadata( 4807 sqlite3 *db, /* Connection handle */ 4808 const char *zDbName, /* Database name or NULL */ 4809 const char *zTableName, /* Table name */ 4810 const char *zColumnName, /* Column name */ 4811 char const **pzDataType, /* OUTPUT: Declared data type */ 4812 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4813 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4814 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4815 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4816); 4817 4818/* 4819** CAPI3REF: Load An Extension 4820** 4821** ^This interface loads an SQLite extension library from the named file. 4822** 4823** ^The sqlite3_load_extension() interface attempts to load an 4824** SQLite extension library contained in the file zFile. 4825** 4826** ^The entry point is zProc. 4827** ^zProc may be 0, in which case the name of the entry point 4828** defaults to "sqlite3_extension_init". 4829** ^The sqlite3_load_extension() interface returns 4830** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4831** ^If an error occurs and pzErrMsg is not 0, then the 4832** [sqlite3_load_extension()] interface shall attempt to 4833** fill *pzErrMsg with error message text stored in memory 4834** obtained from [sqlite3_malloc()]. The calling function 4835** should free this memory by calling [sqlite3_free()]. 4836** 4837** ^Extension loading must be enabled using 4838** [sqlite3_enable_load_extension()] prior to calling this API, 4839** otherwise an error will be returned. 4840** 4841** See also the [load_extension() SQL function]. 4842*/ 4843int sqlite3_load_extension( 4844 sqlite3 *db, /* Load the extension into this database connection */ 4845 const char *zFile, /* Name of the shared library containing extension */ 4846 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4847 char **pzErrMsg /* Put error message here if not 0 */ 4848); 4849 4850/* 4851** CAPI3REF: Enable Or Disable Extension Loading 4852** 4853** ^So as not to open security holes in older applications that are 4854** unprepared to deal with extension loading, and as a means of disabling 4855** extension loading while evaluating user-entered SQL, the following API 4856** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4857** 4858** ^Extension loading is off by default. See ticket #1863. 4859** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4860** to turn extension loading on and call it with onoff==0 to turn 4861** it back off again. 4862*/ 4863int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4864 4865/* 4866** CAPI3REF: Automatically Load Statically Linked Extensions 4867** 4868** ^This interface causes the xEntryPoint() function to be invoked for 4869** each new [database connection] that is created. The idea here is that 4870** xEntryPoint() is the entry point for a statically linked SQLite extension 4871** that is to be automatically loaded into all new database connections. 4872** 4873** ^(Even though the function prototype shows that xEntryPoint() takes 4874** no arguments and returns void, SQLite invokes xEntryPoint() with three 4875** arguments and expects and integer result as if the signature of the 4876** entry point where as follows: 4877** 4878** <blockquote><pre> 4879** int xEntryPoint( 4880** sqlite3 *db, 4881** const char **pzErrMsg, 4882** const struct sqlite3_api_routines *pThunk 4883** ); 4884** </pre></blockquote>)^ 4885** 4886** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 4887** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 4888** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 4889** is NULL before calling the xEntryPoint(). ^SQLite will invoke 4890** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 4891** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 4892** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 4893** 4894** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 4895** on the list of automatic extensions is a harmless no-op. ^No entry point 4896** will be called more than once for each database connection that is opened. 4897** 4898** See also: [sqlite3_reset_auto_extension()]. 4899*/ 4900int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4901 4902/* 4903** CAPI3REF: Reset Automatic Extension Loading 4904** 4905** ^This interface disables all automatic extensions previously 4906** registered using [sqlite3_auto_extension()]. 4907*/ 4908void sqlite3_reset_auto_extension(void); 4909 4910/* 4911** The interface to the virtual-table mechanism is currently considered 4912** to be experimental. The interface might change in incompatible ways. 4913** If this is a problem for you, do not use the interface at this time. 4914** 4915** When the virtual-table mechanism stabilizes, we will declare the 4916** interface fixed, support it indefinitely, and remove this comment. 4917*/ 4918 4919/* 4920** Structures used by the virtual table interface 4921*/ 4922typedef struct sqlite3_vtab sqlite3_vtab; 4923typedef struct sqlite3_index_info sqlite3_index_info; 4924typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4925typedef struct sqlite3_module sqlite3_module; 4926 4927/* 4928** CAPI3REF: Virtual Table Object 4929** KEYWORDS: sqlite3_module {virtual table module} 4930** 4931** This structure, sometimes called a "virtual table module", 4932** defines the implementation of a [virtual tables]. 4933** This structure consists mostly of methods for the module. 4934** 4935** ^A virtual table module is created by filling in a persistent 4936** instance of this structure and passing a pointer to that instance 4937** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4938** ^The registration remains valid until it is replaced by a different 4939** module or until the [database connection] closes. The content 4940** of this structure must not change while it is registered with 4941** any database connection. 4942*/ 4943struct sqlite3_module { 4944 int iVersion; 4945 int (*xCreate)(sqlite3*, void *pAux, 4946 int argc, const char *const*argv, 4947 sqlite3_vtab **ppVTab, char**); 4948 int (*xConnect)(sqlite3*, void *pAux, 4949 int argc, const char *const*argv, 4950 sqlite3_vtab **ppVTab, char**); 4951 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4952 int (*xDisconnect)(sqlite3_vtab *pVTab); 4953 int (*xDestroy)(sqlite3_vtab *pVTab); 4954 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4955 int (*xClose)(sqlite3_vtab_cursor*); 4956 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4957 int argc, sqlite3_value **argv); 4958 int (*xNext)(sqlite3_vtab_cursor*); 4959 int (*xEof)(sqlite3_vtab_cursor*); 4960 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4961 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4962 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4963 int (*xBegin)(sqlite3_vtab *pVTab); 4964 int (*xSync)(sqlite3_vtab *pVTab); 4965 int (*xCommit)(sqlite3_vtab *pVTab); 4966 int (*xRollback)(sqlite3_vtab *pVTab); 4967 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4968 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4969 void **ppArg); 4970 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4971 /* The methods above are in version 1 of the sqlite_module object. Those 4972 ** below are for version 2 and greater. */ 4973 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 4974 int (*xRelease)(sqlite3_vtab *pVTab, int); 4975 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 4976}; 4977 4978/* 4979** CAPI3REF: Virtual Table Indexing Information 4980** KEYWORDS: sqlite3_index_info 4981** 4982** The sqlite3_index_info structure and its substructures is used as part 4983** of the [virtual table] interface to 4984** pass information into and receive the reply from the [xBestIndex] 4985** method of a [virtual table module]. The fields under **Inputs** are the 4986** inputs to xBestIndex and are read-only. xBestIndex inserts its 4987** results into the **Outputs** fields. 4988** 4989** ^(The aConstraint[] array records WHERE clause constraints of the form: 4990** 4991** <blockquote>column OP expr</blockquote> 4992** 4993** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4994** stored in aConstraint[].op using one of the 4995** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 4996** ^(The index of the column is stored in 4997** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4998** expr on the right-hand side can be evaluated (and thus the constraint 4999** is usable) and false if it cannot.)^ 5000** 5001** ^The optimizer automatically inverts terms of the form "expr OP column" 5002** and makes other simplifications to the WHERE clause in an attempt to 5003** get as many WHERE clause terms into the form shown above as possible. 5004** ^The aConstraint[] array only reports WHERE clause terms that are 5005** relevant to the particular virtual table being queried. 5006** 5007** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5008** ^Each term of aOrderBy records a column of the ORDER BY clause. 5009** 5010** The [xBestIndex] method must fill aConstraintUsage[] with information 5011** about what parameters to pass to xFilter. ^If argvIndex>0 then 5012** the right-hand side of the corresponding aConstraint[] is evaluated 5013** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5014** is true, then the constraint is assumed to be fully handled by the 5015** virtual table and is not checked again by SQLite.)^ 5016** 5017** ^The idxNum and idxPtr values are recorded and passed into the 5018** [xFilter] method. 5019** ^[sqlite3_free()] is used to free idxPtr if and only if 5020** needToFreeIdxPtr is true. 5021** 5022** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5023** the correct order to satisfy the ORDER BY clause so that no separate 5024** sorting step is required. 5025** 5026** ^The estimatedCost value is an estimate of the cost of doing the 5027** particular lookup. A full scan of a table with N entries should have 5028** a cost of N. A binary search of a table of N entries should have a 5029** cost of approximately log(N). 5030*/ 5031struct sqlite3_index_info { 5032 /* Inputs */ 5033 int nConstraint; /* Number of entries in aConstraint */ 5034 struct sqlite3_index_constraint { 5035 int iColumn; /* Column on left-hand side of constraint */ 5036 unsigned char op; /* Constraint operator */ 5037 unsigned char usable; /* True if this constraint is usable */ 5038 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5039 } *aConstraint; /* Table of WHERE clause constraints */ 5040 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5041 struct sqlite3_index_orderby { 5042 int iColumn; /* Column number */ 5043 unsigned char desc; /* True for DESC. False for ASC. */ 5044 } *aOrderBy; /* The ORDER BY clause */ 5045 /* Outputs */ 5046 struct sqlite3_index_constraint_usage { 5047 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5048 unsigned char omit; /* Do not code a test for this constraint */ 5049 } *aConstraintUsage; 5050 int idxNum; /* Number used to identify the index */ 5051 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5052 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5053 int orderByConsumed; /* True if output is already ordered */ 5054 double estimatedCost; /* Estimated cost of using this index */ 5055}; 5056 5057/* 5058** CAPI3REF: Virtual Table Constraint Operator Codes 5059** 5060** These macros defined the allowed values for the 5061** [sqlite3_index_info].aConstraint[].op field. Each value represents 5062** an operator that is part of a constraint term in the wHERE clause of 5063** a query that uses a [virtual table]. 5064*/ 5065#define SQLITE_INDEX_CONSTRAINT_EQ 2 5066#define SQLITE_INDEX_CONSTRAINT_GT 4 5067#define SQLITE_INDEX_CONSTRAINT_LE 8 5068#define SQLITE_INDEX_CONSTRAINT_LT 16 5069#define SQLITE_INDEX_CONSTRAINT_GE 32 5070#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5071 5072/* 5073** CAPI3REF: Register A Virtual Table Implementation 5074** 5075** ^These routines are used to register a new [virtual table module] name. 5076** ^Module names must be registered before 5077** creating a new [virtual table] using the module and before using a 5078** preexisting [virtual table] for the module. 5079** 5080** ^The module name is registered on the [database connection] specified 5081** by the first parameter. ^The name of the module is given by the 5082** second parameter. ^The third parameter is a pointer to 5083** the implementation of the [virtual table module]. ^The fourth 5084** parameter is an arbitrary client data pointer that is passed through 5085** into the [xCreate] and [xConnect] methods of the virtual table module 5086** when a new virtual table is be being created or reinitialized. 5087** 5088** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5089** is a pointer to a destructor for the pClientData. ^SQLite will 5090** invoke the destructor function (if it is not NULL) when SQLite 5091** no longer needs the pClientData pointer. ^The destructor will also 5092** be invoked if the call to sqlite3_create_module_v2() fails. 5093** ^The sqlite3_create_module() 5094** interface is equivalent to sqlite3_create_module_v2() with a NULL 5095** destructor. 5096*/ 5097int sqlite3_create_module( 5098 sqlite3 *db, /* SQLite connection to register module with */ 5099 const char *zName, /* Name of the module */ 5100 const sqlite3_module *p, /* Methods for the module */ 5101 void *pClientData /* Client data for xCreate/xConnect */ 5102); 5103int sqlite3_create_module_v2( 5104 sqlite3 *db, /* SQLite connection to register module with */ 5105 const char *zName, /* Name of the module */ 5106 const sqlite3_module *p, /* Methods for the module */ 5107 void *pClientData, /* Client data for xCreate/xConnect */ 5108 void(*xDestroy)(void*) /* Module destructor function */ 5109); 5110 5111/* 5112** CAPI3REF: Virtual Table Instance Object 5113** KEYWORDS: sqlite3_vtab 5114** 5115** Every [virtual table module] implementation uses a subclass 5116** of this object to describe a particular instance 5117** of the [virtual table]. Each subclass will 5118** be tailored to the specific needs of the module implementation. 5119** The purpose of this superclass is to define certain fields that are 5120** common to all module implementations. 5121** 5122** ^Virtual tables methods can set an error message by assigning a 5123** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5124** take care that any prior string is freed by a call to [sqlite3_free()] 5125** prior to assigning a new string to zErrMsg. ^After the error message 5126** is delivered up to the client application, the string will be automatically 5127** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5128*/ 5129struct sqlite3_vtab { 5130 const sqlite3_module *pModule; /* The module for this virtual table */ 5131 int nRef; /* NO LONGER USED */ 5132 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5133 /* Virtual table implementations will typically add additional fields */ 5134}; 5135 5136/* 5137** CAPI3REF: Virtual Table Cursor Object 5138** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5139** 5140** Every [virtual table module] implementation uses a subclass of the 5141** following structure to describe cursors that point into the 5142** [virtual table] and are used 5143** to loop through the virtual table. Cursors are created using the 5144** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5145** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5146** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5147** of the module. Each module implementation will define 5148** the content of a cursor structure to suit its own needs. 5149** 5150** This superclass exists in order to define fields of the cursor that 5151** are common to all implementations. 5152*/ 5153struct sqlite3_vtab_cursor { 5154 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5155 /* Virtual table implementations will typically add additional fields */ 5156}; 5157 5158/* 5159** CAPI3REF: Declare The Schema Of A Virtual Table 5160** 5161** ^The [xCreate] and [xConnect] methods of a 5162** [virtual table module] call this interface 5163** to declare the format (the names and datatypes of the columns) of 5164** the virtual tables they implement. 5165*/ 5166int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5167 5168/* 5169** CAPI3REF: Overload A Function For A Virtual Table 5170** 5171** ^(Virtual tables can provide alternative implementations of functions 5172** using the [xFindFunction] method of the [virtual table module]. 5173** But global versions of those functions 5174** must exist in order to be overloaded.)^ 5175** 5176** ^(This API makes sure a global version of a function with a particular 5177** name and number of parameters exists. If no such function exists 5178** before this API is called, a new function is created.)^ ^The implementation 5179** of the new function always causes an exception to be thrown. So 5180** the new function is not good for anything by itself. Its only 5181** purpose is to be a placeholder function that can be overloaded 5182** by a [virtual table]. 5183*/ 5184int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5185 5186/* 5187** The interface to the virtual-table mechanism defined above (back up 5188** to a comment remarkably similar to this one) is currently considered 5189** to be experimental. The interface might change in incompatible ways. 5190** If this is a problem for you, do not use the interface at this time. 5191** 5192** When the virtual-table mechanism stabilizes, we will declare the 5193** interface fixed, support it indefinitely, and remove this comment. 5194*/ 5195 5196/* 5197** CAPI3REF: A Handle To An Open BLOB 5198** KEYWORDS: {BLOB handle} {BLOB handles} 5199** 5200** An instance of this object represents an open BLOB on which 5201** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5202** ^Objects of this type are created by [sqlite3_blob_open()] 5203** and destroyed by [sqlite3_blob_close()]. 5204** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5205** can be used to read or write small subsections of the BLOB. 5206** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5207*/ 5208typedef struct sqlite3_blob sqlite3_blob; 5209 5210/* 5211** CAPI3REF: Open A BLOB For Incremental I/O 5212** 5213** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5214** in row iRow, column zColumn, table zTable in database zDb; 5215** in other words, the same BLOB that would be selected by: 5216** 5217** <pre> 5218** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5219** </pre>)^ 5220** 5221** ^If the flags parameter is non-zero, then the BLOB is opened for read 5222** and write access. ^If it is zero, the BLOB is opened for read access. 5223** ^It is not possible to open a column that is part of an index or primary 5224** key for writing. ^If [foreign key constraints] are enabled, it is 5225** not possible to open a column that is part of a [child key] for writing. 5226** 5227** ^Note that the database name is not the filename that contains 5228** the database but rather the symbolic name of the database that 5229** appears after the AS keyword when the database is connected using [ATTACH]. 5230** ^For the main database file, the database name is "main". 5231** ^For TEMP tables, the database name is "temp". 5232** 5233** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5234** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5235** to be a null pointer.)^ 5236** ^This function sets the [database connection] error code and message 5237** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5238** functions. ^Note that the *ppBlob variable is always initialized in a 5239** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5240** regardless of the success or failure of this routine. 5241** 5242** ^(If the row that a BLOB handle points to is modified by an 5243** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5244** then the BLOB handle is marked as "expired". 5245** This is true if any column of the row is changed, even a column 5246** other than the one the BLOB handle is open on.)^ 5247** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5248** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5249** ^(Changes written into a BLOB prior to the BLOB expiring are not 5250** rolled back by the expiration of the BLOB. Such changes will eventually 5251** commit if the transaction continues to completion.)^ 5252** 5253** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5254** the opened blob. ^The size of a blob may not be changed by this 5255** interface. Use the [UPDATE] SQL command to change the size of a 5256** blob. 5257** 5258** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5259** and the built-in [zeroblob] SQL function can be used, if desired, 5260** to create an empty, zero-filled blob in which to read or write using 5261** this interface. 5262** 5263** To avoid a resource leak, every open [BLOB handle] should eventually 5264** be released by a call to [sqlite3_blob_close()]. 5265*/ 5266int sqlite3_blob_open( 5267 sqlite3*, 5268 const char *zDb, 5269 const char *zTable, 5270 const char *zColumn, 5271 sqlite3_int64 iRow, 5272 int flags, 5273 sqlite3_blob **ppBlob 5274); 5275 5276/* 5277** CAPI3REF: Move a BLOB Handle to a New Row 5278** 5279** ^This function is used to move an existing blob handle so that it points 5280** to a different row of the same database table. ^The new row is identified 5281** by the rowid value passed as the second argument. Only the row can be 5282** changed. ^The database, table and column on which the blob handle is open 5283** remain the same. Moving an existing blob handle to a new row can be 5284** faster than closing the existing handle and opening a new one. 5285** 5286** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5287** it must exist and there must be either a blob or text value stored in 5288** the nominated column.)^ ^If the new row is not present in the table, or if 5289** it does not contain a blob or text value, or if another error occurs, an 5290** SQLite error code is returned and the blob handle is considered aborted. 5291** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5292** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5293** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5294** always returns zero. 5295** 5296** ^This function sets the database handle error code and message. 5297*/ 5298SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5299 5300/* 5301** CAPI3REF: Close A BLOB Handle 5302** 5303** ^Closes an open [BLOB handle]. 5304** 5305** ^Closing a BLOB shall cause the current transaction to commit 5306** if there are no other BLOBs, no pending prepared statements, and the 5307** database connection is in [autocommit mode]. 5308** ^If any writes were made to the BLOB, they might be held in cache 5309** until the close operation if they will fit. 5310** 5311** ^(Closing the BLOB often forces the changes 5312** out to disk and so if any I/O errors occur, they will likely occur 5313** at the time when the BLOB is closed. Any errors that occur during 5314** closing are reported as a non-zero return value.)^ 5315** 5316** ^(The BLOB is closed unconditionally. Even if this routine returns 5317** an error code, the BLOB is still closed.)^ 5318** 5319** ^Calling this routine with a null pointer (such as would be returned 5320** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5321*/ 5322int sqlite3_blob_close(sqlite3_blob *); 5323 5324/* 5325** CAPI3REF: Return The Size Of An Open BLOB 5326** 5327** ^Returns the size in bytes of the BLOB accessible via the 5328** successfully opened [BLOB handle] in its only argument. ^The 5329** incremental blob I/O routines can only read or overwriting existing 5330** blob content; they cannot change the size of a blob. 5331** 5332** This routine only works on a [BLOB handle] which has been created 5333** by a prior successful call to [sqlite3_blob_open()] and which has not 5334** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5335** to this routine results in undefined and probably undesirable behavior. 5336*/ 5337int sqlite3_blob_bytes(sqlite3_blob *); 5338 5339/* 5340** CAPI3REF: Read Data From A BLOB Incrementally 5341** 5342** ^(This function is used to read data from an open [BLOB handle] into a 5343** caller-supplied buffer. N bytes of data are copied into buffer Z 5344** from the open BLOB, starting at offset iOffset.)^ 5345** 5346** ^If offset iOffset is less than N bytes from the end of the BLOB, 5347** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5348** less than zero, [SQLITE_ERROR] is returned and no data is read. 5349** ^The size of the blob (and hence the maximum value of N+iOffset) 5350** can be determined using the [sqlite3_blob_bytes()] interface. 5351** 5352** ^An attempt to read from an expired [BLOB handle] fails with an 5353** error code of [SQLITE_ABORT]. 5354** 5355** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5356** Otherwise, an [error code] or an [extended error code] is returned.)^ 5357** 5358** This routine only works on a [BLOB handle] which has been created 5359** by a prior successful call to [sqlite3_blob_open()] and which has not 5360** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5361** to this routine results in undefined and probably undesirable behavior. 5362** 5363** See also: [sqlite3_blob_write()]. 5364*/ 5365int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5366 5367/* 5368** CAPI3REF: Write Data Into A BLOB Incrementally 5369** 5370** ^This function is used to write data into an open [BLOB handle] from a 5371** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5372** into the open BLOB, starting at offset iOffset. 5373** 5374** ^If the [BLOB handle] passed as the first argument was not opened for 5375** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5376** this function returns [SQLITE_READONLY]. 5377** 5378** ^This function may only modify the contents of the BLOB; it is 5379** not possible to increase the size of a BLOB using this API. 5380** ^If offset iOffset is less than N bytes from the end of the BLOB, 5381** [SQLITE_ERROR] is returned and no data is written. ^If N is 5382** less than zero [SQLITE_ERROR] is returned and no data is written. 5383** The size of the BLOB (and hence the maximum value of N+iOffset) 5384** can be determined using the [sqlite3_blob_bytes()] interface. 5385** 5386** ^An attempt to write to an expired [BLOB handle] fails with an 5387** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5388** before the [BLOB handle] expired are not rolled back by the 5389** expiration of the handle, though of course those changes might 5390** have been overwritten by the statement that expired the BLOB handle 5391** or by other independent statements. 5392** 5393** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5394** Otherwise, an [error code] or an [extended error code] is returned.)^ 5395** 5396** This routine only works on a [BLOB handle] which has been created 5397** by a prior successful call to [sqlite3_blob_open()] and which has not 5398** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5399** to this routine results in undefined and probably undesirable behavior. 5400** 5401** See also: [sqlite3_blob_read()]. 5402*/ 5403int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5404 5405/* 5406** CAPI3REF: Virtual File System Objects 5407** 5408** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5409** that SQLite uses to interact 5410** with the underlying operating system. Most SQLite builds come with a 5411** single default VFS that is appropriate for the host computer. 5412** New VFSes can be registered and existing VFSes can be unregistered. 5413** The following interfaces are provided. 5414** 5415** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5416** ^Names are case sensitive. 5417** ^Names are zero-terminated UTF-8 strings. 5418** ^If there is no match, a NULL pointer is returned. 5419** ^If zVfsName is NULL then the default VFS is returned. 5420** 5421** ^New VFSes are registered with sqlite3_vfs_register(). 5422** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5423** ^The same VFS can be registered multiple times without injury. 5424** ^To make an existing VFS into the default VFS, register it again 5425** with the makeDflt flag set. If two different VFSes with the 5426** same name are registered, the behavior is undefined. If a 5427** VFS is registered with a name that is NULL or an empty string, 5428** then the behavior is undefined. 5429** 5430** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5431** ^(If the default VFS is unregistered, another VFS is chosen as 5432** the default. The choice for the new VFS is arbitrary.)^ 5433*/ 5434sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5435int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5436int sqlite3_vfs_unregister(sqlite3_vfs*); 5437 5438/* 5439** CAPI3REF: Mutexes 5440** 5441** The SQLite core uses these routines for thread 5442** synchronization. Though they are intended for internal 5443** use by SQLite, code that links against SQLite is 5444** permitted to use any of these routines. 5445** 5446** The SQLite source code contains multiple implementations 5447** of these mutex routines. An appropriate implementation 5448** is selected automatically at compile-time. ^(The following 5449** implementations are available in the SQLite core: 5450** 5451** <ul> 5452** <li> SQLITE_MUTEX_OS2 5453** <li> SQLITE_MUTEX_PTHREADS 5454** <li> SQLITE_MUTEX_W32 5455** <li> SQLITE_MUTEX_NOOP 5456** </ul>)^ 5457** 5458** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5459** that does no real locking and is appropriate for use in 5460** a single-threaded application. ^The SQLITE_MUTEX_OS2, 5461** SQLITE_MUTEX_PTHREADS, and SQLITE_MUTEX_W32 implementations 5462** are appropriate for use on OS/2, Unix, and Windows. 5463** 5464** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5465** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5466** implementation is included with the library. In this case the 5467** application must supply a custom mutex implementation using the 5468** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5469** before calling sqlite3_initialize() or any other public sqlite3_ 5470** function that calls sqlite3_initialize().)^ 5471** 5472** ^The sqlite3_mutex_alloc() routine allocates a new 5473** mutex and returns a pointer to it. ^If it returns NULL 5474** that means that a mutex could not be allocated. ^SQLite 5475** will unwind its stack and return an error. ^(The argument 5476** to sqlite3_mutex_alloc() is one of these integer constants: 5477** 5478** <ul> 5479** <li> SQLITE_MUTEX_FAST 5480** <li> SQLITE_MUTEX_RECURSIVE 5481** <li> SQLITE_MUTEX_STATIC_MASTER 5482** <li> SQLITE_MUTEX_STATIC_MEM 5483** <li> SQLITE_MUTEX_STATIC_MEM2 5484** <li> SQLITE_MUTEX_STATIC_PRNG 5485** <li> SQLITE_MUTEX_STATIC_LRU 5486** <li> SQLITE_MUTEX_STATIC_LRU2 5487** </ul>)^ 5488** 5489** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5490** cause sqlite3_mutex_alloc() to create 5491** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5492** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5493** The mutex implementation does not need to make a distinction 5494** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5495** not want to. ^SQLite will only request a recursive mutex in 5496** cases where it really needs one. ^If a faster non-recursive mutex 5497** implementation is available on the host platform, the mutex subsystem 5498** might return such a mutex in response to SQLITE_MUTEX_FAST. 5499** 5500** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5501** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5502** a pointer to a static preexisting mutex. ^Six static mutexes are 5503** used by the current version of SQLite. Future versions of SQLite 5504** may add additional static mutexes. Static mutexes are for internal 5505** use by SQLite only. Applications that use SQLite mutexes should 5506** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5507** SQLITE_MUTEX_RECURSIVE. 5508** 5509** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5510** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5511** returns a different mutex on every call. ^But for the static 5512** mutex types, the same mutex is returned on every call that has 5513** the same type number. 5514** 5515** ^The sqlite3_mutex_free() routine deallocates a previously 5516** allocated dynamic mutex. ^SQLite is careful to deallocate every 5517** dynamic mutex that it allocates. The dynamic mutexes must not be in 5518** use when they are deallocated. Attempting to deallocate a static 5519** mutex results in undefined behavior. ^SQLite never deallocates 5520** a static mutex. 5521** 5522** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5523** to enter a mutex. ^If another thread is already within the mutex, 5524** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5525** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5526** upon successful entry. ^(Mutexes created using 5527** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5528** In such cases the, 5529** mutex must be exited an equal number of times before another thread 5530** can enter.)^ ^(If the same thread tries to enter any other 5531** kind of mutex more than once, the behavior is undefined. 5532** SQLite will never exhibit 5533** such behavior in its own use of mutexes.)^ 5534** 5535** ^(Some systems (for example, Windows 95) do not support the operation 5536** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5537** will always return SQLITE_BUSY. The SQLite core only ever uses 5538** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5539** 5540** ^The sqlite3_mutex_leave() routine exits a mutex that was 5541** previously entered by the same thread. ^(The behavior 5542** is undefined if the mutex is not currently entered by the 5543** calling thread or is not currently allocated. SQLite will 5544** never do either.)^ 5545** 5546** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5547** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5548** behave as no-ops. 5549** 5550** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5551*/ 5552sqlite3_mutex *sqlite3_mutex_alloc(int); 5553void sqlite3_mutex_free(sqlite3_mutex*); 5554void sqlite3_mutex_enter(sqlite3_mutex*); 5555int sqlite3_mutex_try(sqlite3_mutex*); 5556void sqlite3_mutex_leave(sqlite3_mutex*); 5557 5558/* 5559** CAPI3REF: Mutex Methods Object 5560** 5561** An instance of this structure defines the low-level routines 5562** used to allocate and use mutexes. 5563** 5564** Usually, the default mutex implementations provided by SQLite are 5565** sufficient, however the user has the option of substituting a custom 5566** implementation for specialized deployments or systems for which SQLite 5567** does not provide a suitable implementation. In this case, the user 5568** creates and populates an instance of this structure to pass 5569** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5570** Additionally, an instance of this structure can be used as an 5571** output variable when querying the system for the current mutex 5572** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5573** 5574** ^The xMutexInit method defined by this structure is invoked as 5575** part of system initialization by the sqlite3_initialize() function. 5576** ^The xMutexInit routine is called by SQLite exactly once for each 5577** effective call to [sqlite3_initialize()]. 5578** 5579** ^The xMutexEnd method defined by this structure is invoked as 5580** part of system shutdown by the sqlite3_shutdown() function. The 5581** implementation of this method is expected to release all outstanding 5582** resources obtained by the mutex methods implementation, especially 5583** those obtained by the xMutexInit method. ^The xMutexEnd() 5584** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5585** 5586** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5587** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5588** xMutexNotheld) implement the following interfaces (respectively): 5589** 5590** <ul> 5591** <li> [sqlite3_mutex_alloc()] </li> 5592** <li> [sqlite3_mutex_free()] </li> 5593** <li> [sqlite3_mutex_enter()] </li> 5594** <li> [sqlite3_mutex_try()] </li> 5595** <li> [sqlite3_mutex_leave()] </li> 5596** <li> [sqlite3_mutex_held()] </li> 5597** <li> [sqlite3_mutex_notheld()] </li> 5598** </ul>)^ 5599** 5600** The only difference is that the public sqlite3_XXX functions enumerated 5601** above silently ignore any invocations that pass a NULL pointer instead 5602** of a valid mutex handle. The implementations of the methods defined 5603** by this structure are not required to handle this case, the results 5604** of passing a NULL pointer instead of a valid mutex handle are undefined 5605** (i.e. it is acceptable to provide an implementation that segfaults if 5606** it is passed a NULL pointer). 5607** 5608** The xMutexInit() method must be threadsafe. ^It must be harmless to 5609** invoke xMutexInit() multiple times within the same process and without 5610** intervening calls to xMutexEnd(). Second and subsequent calls to 5611** xMutexInit() must be no-ops. 5612** 5613** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5614** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5615** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5616** memory allocation for a fast or recursive mutex. 5617** 5618** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5619** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5620** If xMutexInit fails in any way, it is expected to clean up after itself 5621** prior to returning. 5622*/ 5623typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5624struct sqlite3_mutex_methods { 5625 int (*xMutexInit)(void); 5626 int (*xMutexEnd)(void); 5627 sqlite3_mutex *(*xMutexAlloc)(int); 5628 void (*xMutexFree)(sqlite3_mutex *); 5629 void (*xMutexEnter)(sqlite3_mutex *); 5630 int (*xMutexTry)(sqlite3_mutex *); 5631 void (*xMutexLeave)(sqlite3_mutex *); 5632 int (*xMutexHeld)(sqlite3_mutex *); 5633 int (*xMutexNotheld)(sqlite3_mutex *); 5634}; 5635 5636/* 5637** CAPI3REF: Mutex Verification Routines 5638** 5639** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5640** are intended for use inside assert() statements. ^The SQLite core 5641** never uses these routines except inside an assert() and applications 5642** are advised to follow the lead of the core. ^The SQLite core only 5643** provides implementations for these routines when it is compiled 5644** with the SQLITE_DEBUG flag. ^External mutex implementations 5645** are only required to provide these routines if SQLITE_DEBUG is 5646** defined and if NDEBUG is not defined. 5647** 5648** ^These routines should return true if the mutex in their argument 5649** is held or not held, respectively, by the calling thread. 5650** 5651** ^The implementation is not required to provide versions of these 5652** routines that actually work. If the implementation does not provide working 5653** versions of these routines, it should at least provide stubs that always 5654** return true so that one does not get spurious assertion failures. 5655** 5656** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5657** the routine should return 1. This seems counter-intuitive since 5658** clearly the mutex cannot be held if it does not exist. But 5659** the reason the mutex does not exist is because the build is not 5660** using mutexes. And we do not want the assert() containing the 5661** call to sqlite3_mutex_held() to fail, so a non-zero return is 5662** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5663** interface should also return 1 when given a NULL pointer. 5664*/ 5665#ifndef NDEBUG 5666int sqlite3_mutex_held(sqlite3_mutex*); 5667int sqlite3_mutex_notheld(sqlite3_mutex*); 5668#endif 5669 5670/* 5671** CAPI3REF: Mutex Types 5672** 5673** The [sqlite3_mutex_alloc()] interface takes a single argument 5674** which is one of these integer constants. 5675** 5676** The set of static mutexes may change from one SQLite release to the 5677** next. Applications that override the built-in mutex logic must be 5678** prepared to accommodate additional static mutexes. 5679*/ 5680#define SQLITE_MUTEX_FAST 0 5681#define SQLITE_MUTEX_RECURSIVE 1 5682#define SQLITE_MUTEX_STATIC_MASTER 2 5683#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5684#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5685#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5686#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5687#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5688#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5689#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5690 5691/* 5692** CAPI3REF: Retrieve the mutex for a database connection 5693** 5694** ^This interface returns a pointer the [sqlite3_mutex] object that 5695** serializes access to the [database connection] given in the argument 5696** when the [threading mode] is Serialized. 5697** ^If the [threading mode] is Single-thread or Multi-thread then this 5698** routine returns a NULL pointer. 5699*/ 5700sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5701 5702/* 5703** CAPI3REF: Low-Level Control Of Database Files 5704** 5705** ^The [sqlite3_file_control()] interface makes a direct call to the 5706** xFileControl method for the [sqlite3_io_methods] object associated 5707** with a particular database identified by the second argument. ^The 5708** name of the database is "main" for the main database or "temp" for the 5709** TEMP database, or the name that appears after the AS keyword for 5710** databases that are added using the [ATTACH] SQL command. 5711** ^A NULL pointer can be used in place of "main" to refer to the 5712** main database file. 5713** ^The third and fourth parameters to this routine 5714** are passed directly through to the second and third parameters of 5715** the xFileControl method. ^The return value of the xFileControl 5716** method becomes the return value of this routine. 5717** 5718** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5719** a pointer to the underlying [sqlite3_file] object to be written into 5720** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5721** case is a short-circuit path which does not actually invoke the 5722** underlying sqlite3_io_methods.xFileControl method. 5723** 5724** ^If the second parameter (zDbName) does not match the name of any 5725** open database file, then SQLITE_ERROR is returned. ^This error 5726** code is not remembered and will not be recalled by [sqlite3_errcode()] 5727** or [sqlite3_errmsg()]. The underlying xFileControl method might 5728** also return SQLITE_ERROR. There is no way to distinguish between 5729** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5730** xFileControl method. 5731** 5732** See also: [SQLITE_FCNTL_LOCKSTATE] 5733*/ 5734int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5735 5736/* 5737** CAPI3REF: Testing Interface 5738** 5739** ^The sqlite3_test_control() interface is used to read out internal 5740** state of SQLite and to inject faults into SQLite for testing 5741** purposes. ^The first parameter is an operation code that determines 5742** the number, meaning, and operation of all subsequent parameters. 5743** 5744** This interface is not for use by applications. It exists solely 5745** for verifying the correct operation of the SQLite library. Depending 5746** on how the SQLite library is compiled, this interface might not exist. 5747** 5748** The details of the operation codes, their meanings, the parameters 5749** they take, and what they do are all subject to change without notice. 5750** Unlike most of the SQLite API, this function is not guaranteed to 5751** operate consistently from one release to the next. 5752*/ 5753int sqlite3_test_control(int op, ...); 5754 5755/* 5756** CAPI3REF: Testing Interface Operation Codes 5757** 5758** These constants are the valid operation code parameters used 5759** as the first argument to [sqlite3_test_control()]. 5760** 5761** These parameters and their meanings are subject to change 5762** without notice. These values are for testing purposes only. 5763** Applications should not use any of these parameters or the 5764** [sqlite3_test_control()] interface. 5765*/ 5766#define SQLITE_TESTCTRL_FIRST 5 5767#define SQLITE_TESTCTRL_PRNG_SAVE 5 5768#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5769#define SQLITE_TESTCTRL_PRNG_RESET 7 5770#define SQLITE_TESTCTRL_BITVEC_TEST 8 5771#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5772#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5773#define SQLITE_TESTCTRL_PENDING_BYTE 11 5774#define SQLITE_TESTCTRL_ASSERT 12 5775#define SQLITE_TESTCTRL_ALWAYS 13 5776#define SQLITE_TESTCTRL_RESERVE 14 5777#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5778#define SQLITE_TESTCTRL_ISKEYWORD 16 5779#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 5780#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 5781#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 5782#define SQLITE_TESTCTRL_LAST 19 5783 5784/* 5785** CAPI3REF: SQLite Runtime Status 5786** 5787** ^This interface is used to retrieve runtime status information 5788** about the performance of SQLite, and optionally to reset various 5789** highwater marks. ^The first argument is an integer code for 5790** the specific parameter to measure. ^(Recognized integer codes 5791** are of the form [status parameters | SQLITE_STATUS_...].)^ 5792** ^The current value of the parameter is returned into *pCurrent. 5793** ^The highest recorded value is returned in *pHighwater. ^If the 5794** resetFlag is true, then the highest record value is reset after 5795** *pHighwater is written. ^(Some parameters do not record the highest 5796** value. For those parameters 5797** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5798** ^(Other parameters record only the highwater mark and not the current 5799** value. For these latter parameters nothing is written into *pCurrent.)^ 5800** 5801** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5802** non-zero [error code] on failure. 5803** 5804** This routine is threadsafe but is not atomic. This routine can be 5805** called while other threads are running the same or different SQLite 5806** interfaces. However the values returned in *pCurrent and 5807** *pHighwater reflect the status of SQLite at different points in time 5808** and it is possible that another thread might change the parameter 5809** in between the times when *pCurrent and *pHighwater are written. 5810** 5811** See also: [sqlite3_db_status()] 5812*/ 5813int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5814 5815 5816/* 5817** CAPI3REF: Status Parameters 5818** KEYWORDS: {status parameters} 5819** 5820** These integer constants designate various run-time status parameters 5821** that can be returned by [sqlite3_status()]. 5822** 5823** <dl> 5824** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5825** <dd>This parameter is the current amount of memory checked out 5826** using [sqlite3_malloc()], either directly or indirectly. The 5827** figure includes calls made to [sqlite3_malloc()] by the application 5828** and internal memory usage by the SQLite library. Scratch memory 5829** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5830** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5831** this parameter. The amount returned is the sum of the allocation 5832** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5833** 5834** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5835** <dd>This parameter records the largest memory allocation request 5836** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5837** internal equivalents). Only the value returned in the 5838** *pHighwater parameter to [sqlite3_status()] is of interest. 5839** The value written into the *pCurrent parameter is undefined.</dd>)^ 5840** 5841** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5842** <dd>This parameter records the number of separate memory allocations 5843** currently checked out.</dd>)^ 5844** 5845** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5846** <dd>This parameter returns the number of pages used out of the 5847** [pagecache memory allocator] that was configured using 5848** [SQLITE_CONFIG_PAGECACHE]. The 5849** value returned is in pages, not in bytes.</dd>)^ 5850** 5851** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 5852** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5853** <dd>This parameter returns the number of bytes of page cache 5854** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 5855** buffer and where forced to overflow to [sqlite3_malloc()]. The 5856** returned value includes allocations that overflowed because they 5857** where too large (they were larger than the "sz" parameter to 5858** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5859** no space was left in the page cache.</dd>)^ 5860** 5861** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5862** <dd>This parameter records the largest memory allocation request 5863** handed to [pagecache memory allocator]. Only the value returned in the 5864** *pHighwater parameter to [sqlite3_status()] is of interest. 5865** The value written into the *pCurrent parameter is undefined.</dd>)^ 5866** 5867** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5868** <dd>This parameter returns the number of allocations used out of the 5869** [scratch memory allocator] configured using 5870** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5871** in bytes. Since a single thread may only have one scratch allocation 5872** outstanding at time, this parameter also reports the number of threads 5873** using scratch memory at the same time.</dd>)^ 5874** 5875** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5876** <dd>This parameter returns the number of bytes of scratch memory 5877** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 5878** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5879** returned include overflows because the requested allocation was too 5880** larger (that is, because the requested allocation was larger than the 5881** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5882** slots were available. 5883** </dd>)^ 5884** 5885** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5886** <dd>This parameter records the largest memory allocation request 5887** handed to [scratch memory allocator]. Only the value returned in the 5888** *pHighwater parameter to [sqlite3_status()] is of interest. 5889** The value written into the *pCurrent parameter is undefined.</dd>)^ 5890** 5891** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5892** <dd>This parameter records the deepest parser stack. It is only 5893** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5894** </dl> 5895** 5896** New status parameters may be added from time to time. 5897*/ 5898#define SQLITE_STATUS_MEMORY_USED 0 5899#define SQLITE_STATUS_PAGECACHE_USED 1 5900#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5901#define SQLITE_STATUS_SCRATCH_USED 3 5902#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5903#define SQLITE_STATUS_MALLOC_SIZE 5 5904#define SQLITE_STATUS_PARSER_STACK 6 5905#define SQLITE_STATUS_PAGECACHE_SIZE 7 5906#define SQLITE_STATUS_SCRATCH_SIZE 8 5907#define SQLITE_STATUS_MALLOC_COUNT 9 5908 5909/* 5910** CAPI3REF: Database Connection Status 5911** 5912** ^This interface is used to retrieve runtime status information 5913** about a single [database connection]. ^The first argument is the 5914** database connection object to be interrogated. ^The second argument 5915** is an integer constant, taken from the set of 5916** [SQLITE_DBSTATUS options], that 5917** determines the parameter to interrogate. The set of 5918** [SQLITE_DBSTATUS options] is likely 5919** to grow in future releases of SQLite. 5920** 5921** ^The current value of the requested parameter is written into *pCur 5922** and the highest instantaneous value is written into *pHiwtr. ^If 5923** the resetFlg is true, then the highest instantaneous value is 5924** reset back down to the current value. 5925** 5926** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5927** non-zero [error code] on failure. 5928** 5929** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5930*/ 5931int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5932 5933/* 5934** CAPI3REF: Status Parameters for database connections 5935** KEYWORDS: {SQLITE_DBSTATUS options} 5936** 5937** These constants are the available integer "verbs" that can be passed as 5938** the second argument to the [sqlite3_db_status()] interface. 5939** 5940** New verbs may be added in future releases of SQLite. Existing verbs 5941** might be discontinued. Applications should check the return code from 5942** [sqlite3_db_status()] to make sure that the call worked. 5943** The [sqlite3_db_status()] interface will return a non-zero error code 5944** if a discontinued or unsupported verb is invoked. 5945** 5946** <dl> 5947** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5948** <dd>This parameter returns the number of lookaside memory slots currently 5949** checked out.</dd>)^ 5950** 5951** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 5952** <dd>This parameter returns the number malloc attempts that were 5953** satisfied using lookaside memory. Only the high-water value is meaningful; 5954** the current value is always zero.)^ 5955** 5956** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 5957** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 5958** <dd>This parameter returns the number malloc attempts that might have 5959** been satisfied using lookaside memory but failed due to the amount of 5960** memory requested being larger than the lookaside slot size. 5961** Only the high-water value is meaningful; 5962** the current value is always zero.)^ 5963** 5964** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 5965** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 5966** <dd>This parameter returns the number malloc attempts that might have 5967** been satisfied using lookaside memory but failed due to all lookaside 5968** memory already being in use. 5969** Only the high-water value is meaningful; 5970** the current value is always zero.)^ 5971** 5972** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5973** <dd>This parameter returns the approximate number of of bytes of heap 5974** memory used by all pager caches associated with the database connection.)^ 5975** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5976** 5977** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5978** <dd>This parameter returns the approximate number of of bytes of heap 5979** memory used to store the schema for all databases associated 5980** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5981** ^The full amount of memory used by the schemas is reported, even if the 5982** schema memory is shared with other database connections due to 5983** [shared cache mode] being enabled. 5984** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5985** 5986** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5987** <dd>This parameter returns the approximate number of of bytes of heap 5988** and lookaside memory used by all prepared statements associated with 5989** the database connection.)^ 5990** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5991** </dd> 5992** 5993** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 5994** <dd>This parameter returns the number of pager cache hits that have 5995** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 5996** is always 0. 5997** </dd> 5998** 5999** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6000** <dd>This parameter returns the number of pager cache misses that have 6001** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6002** is always 0. 6003** </dd> 6004** 6005** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6006** <dd>This parameter returns the number of dirty cache entries that have 6007** been written to disk. Specifically, the number of pages written to the 6008** wal file in wal mode databases, or the number of pages written to the 6009** database file in rollback mode databases. Any pages written as part of 6010** transaction rollback or database recovery operations are not included. 6011** If an IO or other error occurs while writing a page to disk, the effect 6012** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined). ^The 6013** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6014** </dd> 6015** </dl> 6016*/ 6017#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6018#define SQLITE_DBSTATUS_CACHE_USED 1 6019#define SQLITE_DBSTATUS_SCHEMA_USED 2 6020#define SQLITE_DBSTATUS_STMT_USED 3 6021#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6022#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6023#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6024#define SQLITE_DBSTATUS_CACHE_HIT 7 6025#define SQLITE_DBSTATUS_CACHE_MISS 8 6026#define SQLITE_DBSTATUS_CACHE_WRITE 9 6027#define SQLITE_DBSTATUS_MAX 9 /* Largest defined DBSTATUS */ 6028 6029 6030/* 6031** CAPI3REF: Prepared Statement Status 6032** 6033** ^(Each prepared statement maintains various 6034** [SQLITE_STMTSTATUS counters] that measure the number 6035** of times it has performed specific operations.)^ These counters can 6036** be used to monitor the performance characteristics of the prepared 6037** statements. For example, if the number of table steps greatly exceeds 6038** the number of table searches or result rows, that would tend to indicate 6039** that the prepared statement is using a full table scan rather than 6040** an index. 6041** 6042** ^(This interface is used to retrieve and reset counter values from 6043** a [prepared statement]. The first argument is the prepared statement 6044** object to be interrogated. The second argument 6045** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6046** to be interrogated.)^ 6047** ^The current value of the requested counter is returned. 6048** ^If the resetFlg is true, then the counter is reset to zero after this 6049** interface call returns. 6050** 6051** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6052*/ 6053int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6054 6055/* 6056** CAPI3REF: Status Parameters for prepared statements 6057** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6058** 6059** These preprocessor macros define integer codes that name counter 6060** values associated with the [sqlite3_stmt_status()] interface. 6061** The meanings of the various counters are as follows: 6062** 6063** <dl> 6064** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6065** <dd>^This is the number of times that SQLite has stepped forward in 6066** a table as part of a full table scan. Large numbers for this counter 6067** may indicate opportunities for performance improvement through 6068** careful use of indices.</dd> 6069** 6070** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6071** <dd>^This is the number of sort operations that have occurred. 6072** A non-zero value in this counter may indicate an opportunity to 6073** improvement performance through careful use of indices.</dd> 6074** 6075** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6076** <dd>^This is the number of rows inserted into transient indices that 6077** were created automatically in order to help joins run faster. 6078** A non-zero value in this counter may indicate an opportunity to 6079** improvement performance by adding permanent indices that do not 6080** need to be reinitialized each time the statement is run.</dd> 6081** </dl> 6082*/ 6083#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6084#define SQLITE_STMTSTATUS_SORT 2 6085#define SQLITE_STMTSTATUS_AUTOINDEX 3 6086 6087/* 6088** CAPI3REF: Custom Page Cache Object 6089** 6090** The sqlite3_pcache type is opaque. It is implemented by 6091** the pluggable module. The SQLite core has no knowledge of 6092** its size or internal structure and never deals with the 6093** sqlite3_pcache object except by holding and passing pointers 6094** to the object. 6095** 6096** See [sqlite3_pcache_methods2] for additional information. 6097*/ 6098typedef struct sqlite3_pcache sqlite3_pcache; 6099 6100/* 6101** CAPI3REF: Custom Page Cache Object 6102** 6103** The sqlite3_pcache_page object represents a single page in the 6104** page cache. The page cache will allocate instances of this 6105** object. Various methods of the page cache use pointers to instances 6106** of this object as parameters or as their return value. 6107** 6108** See [sqlite3_pcache_methods2] for additional information. 6109*/ 6110typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6111struct sqlite3_pcache_page { 6112 void *pBuf; /* The content of the page */ 6113 void *pExtra; /* Extra information associated with the page */ 6114}; 6115 6116/* 6117** CAPI3REF: Application Defined Page Cache. 6118** KEYWORDS: {page cache} 6119** 6120** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6121** register an alternative page cache implementation by passing in an 6122** instance of the sqlite3_pcache_methods2 structure.)^ 6123** In many applications, most of the heap memory allocated by 6124** SQLite is used for the page cache. 6125** By implementing a 6126** custom page cache using this API, an application can better control 6127** the amount of memory consumed by SQLite, the way in which 6128** that memory is allocated and released, and the policies used to 6129** determine exactly which parts of a database file are cached and for 6130** how long. 6131** 6132** The alternative page cache mechanism is an 6133** extreme measure that is only needed by the most demanding applications. 6134** The built-in page cache is recommended for most uses. 6135** 6136** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6137** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6138** the application may discard the parameter after the call to 6139** [sqlite3_config()] returns.)^ 6140** 6141** [[the xInit() page cache method]] 6142** ^(The xInit() method is called once for each effective 6143** call to [sqlite3_initialize()])^ 6144** (usually only once during the lifetime of the process). ^(The xInit() 6145** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6146** The intent of the xInit() method is to set up global data structures 6147** required by the custom page cache implementation. 6148** ^(If the xInit() method is NULL, then the 6149** built-in default page cache is used instead of the application defined 6150** page cache.)^ 6151** 6152** [[the xShutdown() page cache method]] 6153** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6154** It can be used to clean up 6155** any outstanding resources before process shutdown, if required. 6156** ^The xShutdown() method may be NULL. 6157** 6158** ^SQLite automatically serializes calls to the xInit method, 6159** so the xInit method need not be threadsafe. ^The 6160** xShutdown method is only called from [sqlite3_shutdown()] so it does 6161** not need to be threadsafe either. All other methods must be threadsafe 6162** in multithreaded applications. 6163** 6164** ^SQLite will never invoke xInit() more than once without an intervening 6165** call to xShutdown(). 6166** 6167** [[the xCreate() page cache methods]] 6168** ^SQLite invokes the xCreate() method to construct a new cache instance. 6169** SQLite will typically create one cache instance for each open database file, 6170** though this is not guaranteed. ^The 6171** first parameter, szPage, is the size in bytes of the pages that must 6172** be allocated by the cache. ^szPage will always a power of two. ^The 6173** second parameter szExtra is a number of bytes of extra storage 6174** associated with each page cache entry. ^The szExtra parameter will 6175** a number less than 250. SQLite will use the 6176** extra szExtra bytes on each page to store metadata about the underlying 6177** database page on disk. The value passed into szExtra depends 6178** on the SQLite version, the target platform, and how SQLite was compiled. 6179** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6180** created will be used to cache database pages of a file stored on disk, or 6181** false if it is used for an in-memory database. The cache implementation 6182** does not have to do anything special based with the value of bPurgeable; 6183** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6184** never invoke xUnpin() except to deliberately delete a page. 6185** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6186** false will always have the "discard" flag set to true. 6187** ^Hence, a cache created with bPurgeable false will 6188** never contain any unpinned pages. 6189** 6190** [[the xCachesize() page cache method]] 6191** ^(The xCachesize() method may be called at any time by SQLite to set the 6192** suggested maximum cache-size (number of pages stored by) the cache 6193** instance passed as the first argument. This is the value configured using 6194** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6195** parameter, the implementation is not required to do anything with this 6196** value; it is advisory only. 6197** 6198** [[the xPagecount() page cache methods]] 6199** The xPagecount() method must return the number of pages currently 6200** stored in the cache, both pinned and unpinned. 6201** 6202** [[the xFetch() page cache methods]] 6203** The xFetch() method locates a page in the cache and returns a pointer to 6204** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6205** The pBuf element of the returned sqlite3_pcache_page object will be a 6206** pointer to a buffer of szPage bytes used to store the content of a 6207** single database page. The pExtra element of sqlite3_pcache_page will be 6208** a pointer to the szExtra bytes of extra storage that SQLite has requested 6209** for each entry in the page cache. 6210** 6211** The page to be fetched is determined by the key. ^The minimum key value 6212** is 1. After it has been retrieved using xFetch, the page is considered 6213** to be "pinned". 6214** 6215** If the requested page is already in the page cache, then the page cache 6216** implementation must return a pointer to the page buffer with its content 6217** intact. If the requested page is not already in the cache, then the 6218** cache implementation should use the value of the createFlag 6219** parameter to help it determined what action to take: 6220** 6221** <table border=1 width=85% align=center> 6222** <tr><th> createFlag <th> Behaviour when page is not already in cache 6223** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6224** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6225** Otherwise return NULL. 6226** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6227** NULL if allocating a new page is effectively impossible. 6228** </table> 6229** 6230** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6231** will only use a createFlag of 2 after a prior call with a createFlag of 1 6232** failed.)^ In between the to xFetch() calls, SQLite may 6233** attempt to unpin one or more cache pages by spilling the content of 6234** pinned pages to disk and synching the operating system disk cache. 6235** 6236** [[the xUnpin() page cache method]] 6237** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6238** as its second argument. If the third parameter, discard, is non-zero, 6239** then the page must be evicted from the cache. 6240** ^If the discard parameter is 6241** zero, then the page may be discarded or retained at the discretion of 6242** page cache implementation. ^The page cache implementation 6243** may choose to evict unpinned pages at any time. 6244** 6245** The cache must not perform any reference counting. A single 6246** call to xUnpin() unpins the page regardless of the number of prior calls 6247** to xFetch(). 6248** 6249** [[the xRekey() page cache methods]] 6250** The xRekey() method is used to change the key value associated with the 6251** page passed as the second argument. If the cache 6252** previously contains an entry associated with newKey, it must be 6253** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6254** to be pinned. 6255** 6256** When SQLite calls the xTruncate() method, the cache must discard all 6257** existing cache entries with page numbers (keys) greater than or equal 6258** to the value of the iLimit parameter passed to xTruncate(). If any 6259** of these pages are pinned, they are implicitly unpinned, meaning that 6260** they can be safely discarded. 6261** 6262** [[the xDestroy() page cache method]] 6263** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6264** All resources associated with the specified cache should be freed. ^After 6265** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6266** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6267** functions. 6268** 6269** [[the xShrink() page cache method]] 6270** ^SQLite invokes the xShrink() method when it wants the page cache to 6271** free up as much of heap memory as possible. The page cache implementation 6272** is not obligated to free any memory, but well-behaved implementations should 6273** do their best. 6274*/ 6275typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6276struct sqlite3_pcache_methods2 { 6277 int iVersion; 6278 void *pArg; 6279 int (*xInit)(void*); 6280 void (*xShutdown)(void*); 6281 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6282 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6283 int (*xPagecount)(sqlite3_pcache*); 6284 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6285 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6286 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6287 unsigned oldKey, unsigned newKey); 6288 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6289 void (*xDestroy)(sqlite3_pcache*); 6290 void (*xShrink)(sqlite3_pcache*); 6291}; 6292 6293/* 6294** This is the obsolete pcache_methods object that has now been replaced 6295** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6296** retained in the header file for backwards compatibility only. 6297*/ 6298typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6299struct sqlite3_pcache_methods { 6300 void *pArg; 6301 int (*xInit)(void*); 6302 void (*xShutdown)(void*); 6303 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6304 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6305 int (*xPagecount)(sqlite3_pcache*); 6306 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6307 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6308 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6309 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6310 void (*xDestroy)(sqlite3_pcache*); 6311}; 6312 6313 6314/* 6315** CAPI3REF: Online Backup Object 6316** 6317** The sqlite3_backup object records state information about an ongoing 6318** online backup operation. ^The sqlite3_backup object is created by 6319** a call to [sqlite3_backup_init()] and is destroyed by a call to 6320** [sqlite3_backup_finish()]. 6321** 6322** See Also: [Using the SQLite Online Backup API] 6323*/ 6324typedef struct sqlite3_backup sqlite3_backup; 6325 6326/* 6327** CAPI3REF: Online Backup API. 6328** 6329** The backup API copies the content of one database into another. 6330** It is useful either for creating backups of databases or 6331** for copying in-memory databases to or from persistent files. 6332** 6333** See Also: [Using the SQLite Online Backup API] 6334** 6335** ^SQLite holds a write transaction open on the destination database file 6336** for the duration of the backup operation. 6337** ^The source database is read-locked only while it is being read; 6338** it is not locked continuously for the entire backup operation. 6339** ^Thus, the backup may be performed on a live source database without 6340** preventing other database connections from 6341** reading or writing to the source database while the backup is underway. 6342** 6343** ^(To perform a backup operation: 6344** <ol> 6345** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6346** backup, 6347** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6348** the data between the two databases, and finally 6349** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6350** associated with the backup operation. 6351** </ol>)^ 6352** There should be exactly one call to sqlite3_backup_finish() for each 6353** successful call to sqlite3_backup_init(). 6354** 6355** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6356** 6357** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6358** [database connection] associated with the destination database 6359** and the database name, respectively. 6360** ^The database name is "main" for the main database, "temp" for the 6361** temporary database, or the name specified after the AS keyword in 6362** an [ATTACH] statement for an attached database. 6363** ^The S and M arguments passed to 6364** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6365** and database name of the source database, respectively. 6366** ^The source and destination [database connections] (parameters S and D) 6367** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6368** an error. 6369** 6370** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6371** returned and an error code and error message are stored in the 6372** destination [database connection] D. 6373** ^The error code and message for the failed call to sqlite3_backup_init() 6374** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6375** [sqlite3_errmsg16()] functions. 6376** ^A successful call to sqlite3_backup_init() returns a pointer to an 6377** [sqlite3_backup] object. 6378** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6379** sqlite3_backup_finish() functions to perform the specified backup 6380** operation. 6381** 6382** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6383** 6384** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6385** the source and destination databases specified by [sqlite3_backup] object B. 6386** ^If N is negative, all remaining source pages are copied. 6387** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6388** are still more pages to be copied, then the function returns [SQLITE_OK]. 6389** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6390** from source to destination, then it returns [SQLITE_DONE]. 6391** ^If an error occurs while running sqlite3_backup_step(B,N), 6392** then an [error code] is returned. ^As well as [SQLITE_OK] and 6393** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6394** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6395** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6396** 6397** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6398** <ol> 6399** <li> the destination database was opened read-only, or 6400** <li> the destination database is using write-ahead-log journaling 6401** and the destination and source page sizes differ, or 6402** <li> the destination database is an in-memory database and the 6403** destination and source page sizes differ. 6404** </ol>)^ 6405** 6406** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6407** the [sqlite3_busy_handler | busy-handler function] 6408** is invoked (if one is specified). ^If the 6409** busy-handler returns non-zero before the lock is available, then 6410** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6411** sqlite3_backup_step() can be retried later. ^If the source 6412** [database connection] 6413** is being used to write to the source database when sqlite3_backup_step() 6414** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6415** case the call to sqlite3_backup_step() can be retried later on. ^(If 6416** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6417** [SQLITE_READONLY] is returned, then 6418** there is no point in retrying the call to sqlite3_backup_step(). These 6419** errors are considered fatal.)^ The application must accept 6420** that the backup operation has failed and pass the backup operation handle 6421** to the sqlite3_backup_finish() to release associated resources. 6422** 6423** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6424** on the destination file. ^The exclusive lock is not released until either 6425** sqlite3_backup_finish() is called or the backup operation is complete 6426** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6427** sqlite3_backup_step() obtains a [shared lock] on the source database that 6428** lasts for the duration of the sqlite3_backup_step() call. 6429** ^Because the source database is not locked between calls to 6430** sqlite3_backup_step(), the source database may be modified mid-way 6431** through the backup process. ^If the source database is modified by an 6432** external process or via a database connection other than the one being 6433** used by the backup operation, then the backup will be automatically 6434** restarted by the next call to sqlite3_backup_step(). ^If the source 6435** database is modified by the using the same database connection as is used 6436** by the backup operation, then the backup database is automatically 6437** updated at the same time. 6438** 6439** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6440** 6441** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6442** application wishes to abandon the backup operation, the application 6443** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6444** ^The sqlite3_backup_finish() interfaces releases all 6445** resources associated with the [sqlite3_backup] object. 6446** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6447** active write-transaction on the destination database is rolled back. 6448** The [sqlite3_backup] object is invalid 6449** and may not be used following a call to sqlite3_backup_finish(). 6450** 6451** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6452** sqlite3_backup_step() errors occurred, regardless or whether or not 6453** sqlite3_backup_step() completed. 6454** ^If an out-of-memory condition or IO error occurred during any prior 6455** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6456** sqlite3_backup_finish() returns the corresponding [error code]. 6457** 6458** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6459** is not a permanent error and does not affect the return value of 6460** sqlite3_backup_finish(). 6461** 6462** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6463** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6464** 6465** ^Each call to sqlite3_backup_step() sets two values inside 6466** the [sqlite3_backup] object: the number of pages still to be backed 6467** up and the total number of pages in the source database file. 6468** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6469** retrieve these two values, respectively. 6470** 6471** ^The values returned by these functions are only updated by 6472** sqlite3_backup_step(). ^If the source database is modified during a backup 6473** operation, then the values are not updated to account for any extra 6474** pages that need to be updated or the size of the source database file 6475** changing. 6476** 6477** <b>Concurrent Usage of Database Handles</b> 6478** 6479** ^The source [database connection] may be used by the application for other 6480** purposes while a backup operation is underway or being initialized. 6481** ^If SQLite is compiled and configured to support threadsafe database 6482** connections, then the source database connection may be used concurrently 6483** from within other threads. 6484** 6485** However, the application must guarantee that the destination 6486** [database connection] is not passed to any other API (by any thread) after 6487** sqlite3_backup_init() is called and before the corresponding call to 6488** sqlite3_backup_finish(). SQLite does not currently check to see 6489** if the application incorrectly accesses the destination [database connection] 6490** and so no error code is reported, but the operations may malfunction 6491** nevertheless. Use of the destination database connection while a 6492** backup is in progress might also also cause a mutex deadlock. 6493** 6494** If running in [shared cache mode], the application must 6495** guarantee that the shared cache used by the destination database 6496** is not accessed while the backup is running. In practice this means 6497** that the application must guarantee that the disk file being 6498** backed up to is not accessed by any connection within the process, 6499** not just the specific connection that was passed to sqlite3_backup_init(). 6500** 6501** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6502** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6503** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6504** APIs are not strictly speaking threadsafe. If they are invoked at the 6505** same time as another thread is invoking sqlite3_backup_step() it is 6506** possible that they return invalid values. 6507*/ 6508sqlite3_backup *sqlite3_backup_init( 6509 sqlite3 *pDest, /* Destination database handle */ 6510 const char *zDestName, /* Destination database name */ 6511 sqlite3 *pSource, /* Source database handle */ 6512 const char *zSourceName /* Source database name */ 6513); 6514int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6515int sqlite3_backup_finish(sqlite3_backup *p); 6516int sqlite3_backup_remaining(sqlite3_backup *p); 6517int sqlite3_backup_pagecount(sqlite3_backup *p); 6518 6519/* 6520** CAPI3REF: Unlock Notification 6521** 6522** ^When running in shared-cache mode, a database operation may fail with 6523** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6524** individual tables within the shared-cache cannot be obtained. See 6525** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6526** ^This API may be used to register a callback that SQLite will invoke 6527** when the connection currently holding the required lock relinquishes it. 6528** ^This API is only available if the library was compiled with the 6529** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6530** 6531** See Also: [Using the SQLite Unlock Notification Feature]. 6532** 6533** ^Shared-cache locks are released when a database connection concludes 6534** its current transaction, either by committing it or rolling it back. 6535** 6536** ^When a connection (known as the blocked connection) fails to obtain a 6537** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6538** identity of the database connection (the blocking connection) that 6539** has locked the required resource is stored internally. ^After an 6540** application receives an SQLITE_LOCKED error, it may call the 6541** sqlite3_unlock_notify() method with the blocked connection handle as 6542** the first argument to register for a callback that will be invoked 6543** when the blocking connections current transaction is concluded. ^The 6544** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6545** call that concludes the blocking connections transaction. 6546** 6547** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6548** there is a chance that the blocking connection will have already 6549** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6550** If this happens, then the specified callback is invoked immediately, 6551** from within the call to sqlite3_unlock_notify().)^ 6552** 6553** ^If the blocked connection is attempting to obtain a write-lock on a 6554** shared-cache table, and more than one other connection currently holds 6555** a read-lock on the same table, then SQLite arbitrarily selects one of 6556** the other connections to use as the blocking connection. 6557** 6558** ^(There may be at most one unlock-notify callback registered by a 6559** blocked connection. If sqlite3_unlock_notify() is called when the 6560** blocked connection already has a registered unlock-notify callback, 6561** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6562** called with a NULL pointer as its second argument, then any existing 6563** unlock-notify callback is canceled. ^The blocked connections 6564** unlock-notify callback may also be canceled by closing the blocked 6565** connection using [sqlite3_close()]. 6566** 6567** The unlock-notify callback is not reentrant. If an application invokes 6568** any sqlite3_xxx API functions from within an unlock-notify callback, a 6569** crash or deadlock may be the result. 6570** 6571** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6572** returns SQLITE_OK. 6573** 6574** <b>Callback Invocation Details</b> 6575** 6576** When an unlock-notify callback is registered, the application provides a 6577** single void* pointer that is passed to the callback when it is invoked. 6578** However, the signature of the callback function allows SQLite to pass 6579** it an array of void* context pointers. The first argument passed to 6580** an unlock-notify callback is a pointer to an array of void* pointers, 6581** and the second is the number of entries in the array. 6582** 6583** When a blocking connections transaction is concluded, there may be 6584** more than one blocked connection that has registered for an unlock-notify 6585** callback. ^If two or more such blocked connections have specified the 6586** same callback function, then instead of invoking the callback function 6587** multiple times, it is invoked once with the set of void* context pointers 6588** specified by the blocked connections bundled together into an array. 6589** This gives the application an opportunity to prioritize any actions 6590** related to the set of unblocked database connections. 6591** 6592** <b>Deadlock Detection</b> 6593** 6594** Assuming that after registering for an unlock-notify callback a 6595** database waits for the callback to be issued before taking any further 6596** action (a reasonable assumption), then using this API may cause the 6597** application to deadlock. For example, if connection X is waiting for 6598** connection Y's transaction to be concluded, and similarly connection 6599** Y is waiting on connection X's transaction, then neither connection 6600** will proceed and the system may remain deadlocked indefinitely. 6601** 6602** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6603** detection. ^If a given call to sqlite3_unlock_notify() would put the 6604** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6605** unlock-notify callback is registered. The system is said to be in 6606** a deadlocked state if connection A has registered for an unlock-notify 6607** callback on the conclusion of connection B's transaction, and connection 6608** B has itself registered for an unlock-notify callback when connection 6609** A's transaction is concluded. ^Indirect deadlock is also detected, so 6610** the system is also considered to be deadlocked if connection B has 6611** registered for an unlock-notify callback on the conclusion of connection 6612** C's transaction, where connection C is waiting on connection A. ^Any 6613** number of levels of indirection are allowed. 6614** 6615** <b>The "DROP TABLE" Exception</b> 6616** 6617** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6618** always appropriate to call sqlite3_unlock_notify(). There is however, 6619** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6620** SQLite checks if there are any currently executing SELECT statements 6621** that belong to the same connection. If there are, SQLITE_LOCKED is 6622** returned. In this case there is no "blocking connection", so invoking 6623** sqlite3_unlock_notify() results in the unlock-notify callback being 6624** invoked immediately. If the application then re-attempts the "DROP TABLE" 6625** or "DROP INDEX" query, an infinite loop might be the result. 6626** 6627** One way around this problem is to check the extended error code returned 6628** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6629** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6630** the special "DROP TABLE/INDEX" case, the extended error code is just 6631** SQLITE_LOCKED.)^ 6632*/ 6633int sqlite3_unlock_notify( 6634 sqlite3 *pBlocked, /* Waiting connection */ 6635 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6636 void *pNotifyArg /* Argument to pass to xNotify */ 6637); 6638 6639 6640/* 6641** CAPI3REF: String Comparison 6642** 6643** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 6644** and extensions to compare the contents of two buffers containing UTF-8 6645** strings in a case-independent fashion, using the same definition of "case 6646** independence" that SQLite uses internally when comparing identifiers. 6647*/ 6648int sqlite3_stricmp(const char *, const char *); 6649int sqlite3_strnicmp(const char *, const char *, int); 6650 6651/* 6652** CAPI3REF: Error Logging Interface 6653** 6654** ^The [sqlite3_log()] interface writes a message into the error log 6655** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6656** ^If logging is enabled, the zFormat string and subsequent arguments are 6657** used with [sqlite3_snprintf()] to generate the final output string. 6658** 6659** The sqlite3_log() interface is intended for use by extensions such as 6660** virtual tables, collating functions, and SQL functions. While there is 6661** nothing to prevent an application from calling sqlite3_log(), doing so 6662** is considered bad form. 6663** 6664** The zFormat string must not be NULL. 6665** 6666** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6667** will not use dynamically allocated memory. The log message is stored in 6668** a fixed-length buffer on the stack. If the log message is longer than 6669** a few hundred characters, it will be truncated to the length of the 6670** buffer. 6671*/ 6672void sqlite3_log(int iErrCode, const char *zFormat, ...); 6673 6674/* 6675** CAPI3REF: Write-Ahead Log Commit Hook 6676** 6677** ^The [sqlite3_wal_hook()] function is used to register a callback that 6678** will be invoked each time a database connection commits data to a 6679** [write-ahead log] (i.e. whenever a transaction is committed in 6680** [journal_mode | journal_mode=WAL mode]). 6681** 6682** ^The callback is invoked by SQLite after the commit has taken place and 6683** the associated write-lock on the database released, so the implementation 6684** may read, write or [checkpoint] the database as required. 6685** 6686** ^The first parameter passed to the callback function when it is invoked 6687** is a copy of the third parameter passed to sqlite3_wal_hook() when 6688** registering the callback. ^The second is a copy of the database handle. 6689** ^The third parameter is the name of the database that was written to - 6690** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6691** is the number of pages currently in the write-ahead log file, 6692** including those that were just committed. 6693** 6694** The callback function should normally return [SQLITE_OK]. ^If an error 6695** code is returned, that error will propagate back up through the 6696** SQLite code base to cause the statement that provoked the callback 6697** to report an error, though the commit will have still occurred. If the 6698** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6699** that does not correspond to any valid SQLite error code, the results 6700** are undefined. 6701** 6702** A single database handle may have at most a single write-ahead log callback 6703** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6704** previously registered write-ahead log callback. ^Note that the 6705** [sqlite3_wal_autocheckpoint()] interface and the 6706** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6707** those overwrite any prior [sqlite3_wal_hook()] settings. 6708*/ 6709void *sqlite3_wal_hook( 6710 sqlite3*, 6711 int(*)(void *,sqlite3*,const char*,int), 6712 void* 6713); 6714 6715/* 6716** CAPI3REF: Configure an auto-checkpoint 6717** 6718** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6719** [sqlite3_wal_hook()] that causes any database on [database connection] D 6720** to automatically [checkpoint] 6721** after committing a transaction if there are N or 6722** more frames in the [write-ahead log] file. ^Passing zero or 6723** a negative value as the nFrame parameter disables automatic 6724** checkpoints entirely. 6725** 6726** ^The callback registered by this function replaces any existing callback 6727** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6728** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6729** configured by this function. 6730** 6731** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6732** from SQL. 6733** 6734** ^Every new [database connection] defaults to having the auto-checkpoint 6735** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6736** pages. The use of this interface 6737** is only necessary if the default setting is found to be suboptimal 6738** for a particular application. 6739*/ 6740int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6741 6742/* 6743** CAPI3REF: Checkpoint a database 6744** 6745** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6746** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6747** empty string, then a checkpoint is run on all databases of 6748** connection D. ^If the database connection D is not in 6749** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6750** 6751** ^The [wal_checkpoint pragma] can be used to invoke this interface 6752** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6753** [wal_autocheckpoint pragma] can be used to cause this interface to be 6754** run whenever the WAL reaches a certain size threshold. 6755** 6756** See also: [sqlite3_wal_checkpoint_v2()] 6757*/ 6758int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6759 6760/* 6761** CAPI3REF: Checkpoint a database 6762** 6763** Run a checkpoint operation on WAL database zDb attached to database 6764** handle db. The specific operation is determined by the value of the 6765** eMode parameter: 6766** 6767** <dl> 6768** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 6769** Checkpoint as many frames as possible without waiting for any database 6770** readers or writers to finish. Sync the db file if all frames in the log 6771** are checkpointed. This mode is the same as calling 6772** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 6773** 6774** <dt>SQLITE_CHECKPOINT_FULL<dd> 6775** This mode blocks (calls the busy-handler callback) until there is no 6776** database writer and all readers are reading from the most recent database 6777** snapshot. It then checkpoints all frames in the log file and syncs the 6778** database file. This call blocks database writers while it is running, 6779** but not database readers. 6780** 6781** <dt>SQLITE_CHECKPOINT_RESTART<dd> 6782** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 6783** checkpointing the log file it blocks (calls the busy-handler callback) 6784** until all readers are reading from the database file only. This ensures 6785** that the next client to write to the database file restarts the log file 6786** from the beginning. This call blocks database writers while it is running, 6787** but not database readers. 6788** </dl> 6789** 6790** If pnLog is not NULL, then *pnLog is set to the total number of frames in 6791** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 6792** the total number of checkpointed frames (including any that were already 6793** checkpointed when this function is called). *pnLog and *pnCkpt may be 6794** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 6795** If no values are available because of an error, they are both set to -1 6796** before returning to communicate this to the caller. 6797** 6798** All calls obtain an exclusive "checkpoint" lock on the database file. If 6799** any other process is running a checkpoint operation at the same time, the 6800** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 6801** busy-handler configured, it will not be invoked in this case. 6802** 6803** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 6804** "writer" lock on the database file. If the writer lock cannot be obtained 6805** immediately, and a busy-handler is configured, it is invoked and the writer 6806** lock retried until either the busy-handler returns 0 or the lock is 6807** successfully obtained. The busy-handler is also invoked while waiting for 6808** database readers as described above. If the busy-handler returns 0 before 6809** the writer lock is obtained or while waiting for database readers, the 6810** checkpoint operation proceeds from that point in the same way as 6811** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 6812** without blocking any further. SQLITE_BUSY is returned in this case. 6813** 6814** If parameter zDb is NULL or points to a zero length string, then the 6815** specified operation is attempted on all WAL databases. In this case the 6816** values written to output parameters *pnLog and *pnCkpt are undefined. If 6817** an SQLITE_BUSY error is encountered when processing one or more of the 6818** attached WAL databases, the operation is still attempted on any remaining 6819** attached databases and SQLITE_BUSY is returned to the caller. If any other 6820** error occurs while processing an attached database, processing is abandoned 6821** and the error code returned to the caller immediately. If no error 6822** (SQLITE_BUSY or otherwise) is encountered while processing the attached 6823** databases, SQLITE_OK is returned. 6824** 6825** If database zDb is the name of an attached database that is not in WAL 6826** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 6827** zDb is not NULL (or a zero length string) and is not the name of any 6828** attached database, SQLITE_ERROR is returned to the caller. 6829*/ 6830int sqlite3_wal_checkpoint_v2( 6831 sqlite3 *db, /* Database handle */ 6832 const char *zDb, /* Name of attached database (or NULL) */ 6833 int eMode, /* SQLITE_CHECKPOINT_* value */ 6834 int *pnLog, /* OUT: Size of WAL log in frames */ 6835 int *pnCkpt /* OUT: Total number of frames checkpointed */ 6836); 6837 6838/* 6839** CAPI3REF: Checkpoint operation parameters 6840** 6841** These constants can be used as the 3rd parameter to 6842** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 6843** documentation for additional information about the meaning and use of 6844** each of these values. 6845*/ 6846#define SQLITE_CHECKPOINT_PASSIVE 0 6847#define SQLITE_CHECKPOINT_FULL 1 6848#define SQLITE_CHECKPOINT_RESTART 2 6849 6850/* 6851** CAPI3REF: Virtual Table Interface Configuration 6852** 6853** This function may be called by either the [xConnect] or [xCreate] method 6854** of a [virtual table] implementation to configure 6855** various facets of the virtual table interface. 6856** 6857** If this interface is invoked outside the context of an xConnect or 6858** xCreate virtual table method then the behavior is undefined. 6859** 6860** At present, there is only one option that may be configured using 6861** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 6862** may be added in the future. 6863*/ 6864int sqlite3_vtab_config(sqlite3*, int op, ...); 6865 6866/* 6867** CAPI3REF: Virtual Table Configuration Options 6868** 6869** These macros define the various options to the 6870** [sqlite3_vtab_config()] interface that [virtual table] implementations 6871** can use to customize and optimize their behavior. 6872** 6873** <dl> 6874** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 6875** <dd>Calls of the form 6876** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 6877** where X is an integer. If X is zero, then the [virtual table] whose 6878** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 6879** support constraints. In this configuration (which is the default) if 6880** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 6881** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 6882** specified as part of the users SQL statement, regardless of the actual 6883** ON CONFLICT mode specified. 6884** 6885** If X is non-zero, then the virtual table implementation guarantees 6886** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 6887** any modifications to internal or persistent data structures have been made. 6888** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 6889** is able to roll back a statement or database transaction, and abandon 6890** or continue processing the current SQL statement as appropriate. 6891** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 6892** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 6893** had been ABORT. 6894** 6895** Virtual table implementations that are required to handle OR REPLACE 6896** must do so within the [xUpdate] method. If a call to the 6897** [sqlite3_vtab_on_conflict()] function indicates that the current ON 6898** CONFLICT policy is REPLACE, the virtual table implementation should 6899** silently replace the appropriate rows within the xUpdate callback and 6900** return SQLITE_OK. Or, if this is not possible, it may return 6901** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 6902** constraint handling. 6903** </dl> 6904*/ 6905#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 6906 6907/* 6908** CAPI3REF: Determine The Virtual Table Conflict Policy 6909** 6910** This function may only be called from within a call to the [xUpdate] method 6911** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 6912** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 6913** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 6914** of the SQL statement that triggered the call to the [xUpdate] method of the 6915** [virtual table]. 6916*/ 6917int sqlite3_vtab_on_conflict(sqlite3 *); 6918 6919/* 6920** CAPI3REF: Conflict resolution modes 6921** 6922** These constants are returned by [sqlite3_vtab_on_conflict()] to 6923** inform a [virtual table] implementation what the [ON CONFLICT] mode 6924** is for the SQL statement being evaluated. 6925** 6926** Note that the [SQLITE_IGNORE] constant is also used as a potential 6927** return value from the [sqlite3_set_authorizer()] callback and that 6928** [SQLITE_ABORT] is also a [result code]. 6929*/ 6930#define SQLITE_ROLLBACK 1 6931/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 6932#define SQLITE_FAIL 3 6933/* #define SQLITE_ABORT 4 // Also an error code */ 6934#define SQLITE_REPLACE 5 6935 6936 6937 6938/* 6939** Undo the hack that converts floating point types to integer for 6940** builds on processors without floating point support. 6941*/ 6942#ifdef SQLITE_OMIT_FLOATING_POINT 6943# undef double 6944#endif 6945 6946#ifdef __cplusplus 6947} /* End of the 'extern "C"' block */ 6948#endif 6949#endif 6950