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** and [sqlite3_close_v2()] are its destructors. There are many other 218** interfaces (such as 219** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 220** [sqlite3_busy_timeout()] to name but three) that are methods on an 221** sqlite3 object. 222*/ 223typedef struct sqlite3 sqlite3; 224 225/* 226** CAPI3REF: 64-Bit Integer Types 227** KEYWORDS: sqlite_int64 sqlite_uint64 228** 229** Because there is no cross-platform way to specify 64-bit integer types 230** SQLite includes typedefs for 64-bit signed and unsigned integers. 231** 232** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 233** The sqlite_int64 and sqlite_uint64 types are supported for backwards 234** compatibility only. 235** 236** ^The sqlite3_int64 and sqlite_int64 types can store integer values 237** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 238** sqlite3_uint64 and sqlite_uint64 types can store integer values 239** between 0 and +18446744073709551615 inclusive. 240*/ 241#ifdef SQLITE_INT64_TYPE 242 typedef SQLITE_INT64_TYPE sqlite_int64; 243 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 244#elif defined(_MSC_VER) || defined(__BORLANDC__) 245 typedef __int64 sqlite_int64; 246 typedef unsigned __int64 sqlite_uint64; 247#else 248 typedef long long int sqlite_int64; 249 typedef unsigned long long int sqlite_uint64; 250#endif 251typedef sqlite_int64 sqlite3_int64; 252typedef sqlite_uint64 sqlite3_uint64; 253 254/* 255** If compiling for a processor that lacks floating point support, 256** substitute integer for floating-point. 257*/ 258#ifdef SQLITE_OMIT_FLOATING_POINT 259# define double sqlite3_int64 260#endif 261 262/* 263** CAPI3REF: Closing A Database Connection 264** 265** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 266** for the [sqlite3] object. 267** ^Calls to sqlite3_close() and sqlite3_close_v2() return SQLITE_OK if 268** the [sqlite3] object is successfully destroyed and all associated 269** resources are deallocated. 270** 271** ^If the database connection is associated with unfinalized prepared 272** statements or unfinished sqlite3_backup objects then sqlite3_close() 273** will leave the database connection open and return [SQLITE_BUSY]. 274** ^If sqlite3_close_v2() is called with unfinalized prepared statements 275** and unfinished sqlite3_backups, then the database connection becomes 276** an unusable "zombie" which will automatically be deallocated when the 277** last prepared statement is finalized or the last sqlite3_backup is 278** finished. The sqlite3_close_v2() interface is intended for use with 279** host languages that are garbage collected, and where the order in which 280** destructors are called is arbitrary. 281** 282** Applications should [sqlite3_finalize | finalize] all [prepared statements], 283** [sqlite3_blob_close | close] all [BLOB handles], and 284** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 285** with the [sqlite3] object prior to attempting to close the object. ^If 286** sqlite3_close_v2() is called on a [database connection] that still has 287** outstanding [prepared statements], [BLOB handles], and/or 288** [sqlite3_backup] objects then it returns SQLITE_OK but the deallocation 289** of resources is deferred until all [prepared statements], [BLOB handles], 290** and [sqlite3_backup] objects are also destroyed. 291** 292** ^If an [sqlite3] object is destroyed while a transaction is open, 293** the transaction is automatically rolled back. 294** 295** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 296** must be either a NULL 297** pointer or an [sqlite3] object pointer obtained 298** from [sqlite3_open()], [sqlite3_open16()], or 299** [sqlite3_open_v2()], and not previously closed. 300** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 301** argument is a harmless no-op. 302*/ 303int sqlite3_close(sqlite3*); 304int sqlite3_close_v2(sqlite3*); 305 306/* 307** The type for a callback function. 308** This is legacy and deprecated. It is included for historical 309** compatibility and is not documented. 310*/ 311typedef int (*sqlite3_callback)(void*,int,char**, char**); 312 313/* 314** CAPI3REF: One-Step Query Execution Interface 315** 316** The sqlite3_exec() interface is a convenience wrapper around 317** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 318** that allows an application to run multiple statements of SQL 319** without having to use a lot of C code. 320** 321** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 322** semicolon-separate SQL statements passed into its 2nd argument, 323** in the context of the [database connection] passed in as its 1st 324** argument. ^If the callback function of the 3rd argument to 325** sqlite3_exec() is not NULL, then it is invoked for each result row 326** coming out of the evaluated SQL statements. ^The 4th argument to 327** sqlite3_exec() is relayed through to the 1st argument of each 328** callback invocation. ^If the callback pointer to sqlite3_exec() 329** is NULL, then no callback is ever invoked and result rows are 330** ignored. 331** 332** ^If an error occurs while evaluating the SQL statements passed into 333** sqlite3_exec(), then execution of the current statement stops and 334** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 335** is not NULL then any error message is written into memory obtained 336** from [sqlite3_malloc()] and passed back through the 5th parameter. 337** To avoid memory leaks, the application should invoke [sqlite3_free()] 338** on error message strings returned through the 5th parameter of 339** of sqlite3_exec() after the error message string is no longer needed. 340** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 341** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 342** NULL before returning. 343** 344** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 345** routine returns SQLITE_ABORT without invoking the callback again and 346** without running any subsequent SQL statements. 347** 348** ^The 2nd argument to the sqlite3_exec() callback function is the 349** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 350** callback is an array of pointers to strings obtained as if from 351** [sqlite3_column_text()], one for each column. ^If an element of a 352** result row is NULL then the corresponding string pointer for the 353** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 354** sqlite3_exec() callback is an array of pointers to strings where each 355** entry represents the name of corresponding result column as obtained 356** from [sqlite3_column_name()]. 357** 358** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 359** to an empty string, or a pointer that contains only whitespace and/or 360** SQL comments, then no SQL statements are evaluated and the database 361** is not changed. 362** 363** Restrictions: 364** 365** <ul> 366** <li> The application must insure that the 1st parameter to sqlite3_exec() 367** is a valid and open [database connection]. 368** <li> The application must not close the [database connection] specified by 369** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 370** <li> The application must not modify the SQL statement text passed into 371** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 372** </ul> 373*/ 374int sqlite3_exec( 375 sqlite3*, /* An open database */ 376 const char *sql, /* SQL to be evaluated */ 377 int (*callback)(void*,int,char**,char**), /* Callback function */ 378 void *, /* 1st argument to callback */ 379 char **errmsg /* Error msg written here */ 380); 381 382/* 383** CAPI3REF: Result Codes 384** KEYWORDS: SQLITE_OK {error code} {error codes} 385** KEYWORDS: {result code} {result codes} 386** 387** Many SQLite functions return an integer result code from the set shown 388** here in order to indicate success or failure. 389** 390** New error codes may be added in future versions of SQLite. 391** 392** See also: [SQLITE_IOERR_READ | extended result codes], 393** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes]. 394*/ 395#define SQLITE_OK 0 /* Successful result */ 396/* beginning-of-error-codes */ 397#define SQLITE_ERROR 1 /* SQL error or missing database */ 398#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 399#define SQLITE_PERM 3 /* Access permission denied */ 400#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 401#define SQLITE_BUSY 5 /* The database file is locked */ 402#define SQLITE_LOCKED 6 /* A table in the database is locked */ 403#define SQLITE_NOMEM 7 /* A malloc() failed */ 404#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 405#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 406#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 407#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 408#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 409#define SQLITE_FULL 13 /* Insertion failed because database is full */ 410#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 411#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 412#define SQLITE_EMPTY 16 /* Database is empty */ 413#define SQLITE_SCHEMA 17 /* The database schema changed */ 414#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 415#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 416#define SQLITE_MISMATCH 20 /* Data type mismatch */ 417#define SQLITE_MISUSE 21 /* Library used incorrectly */ 418#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 419#define SQLITE_AUTH 23 /* Authorization denied */ 420#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 421#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 422#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 423#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 424#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 425#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 426#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 427/* end-of-error-codes */ 428 429/* 430** CAPI3REF: Extended Result Codes 431** KEYWORDS: {extended error code} {extended error codes} 432** KEYWORDS: {extended result code} {extended result codes} 433** 434** In its default configuration, SQLite API routines return one of 26 integer 435** [SQLITE_OK | result codes]. However, experience has shown that many of 436** these result codes are too coarse-grained. They do not provide as 437** much information about problems as programmers might like. In an effort to 438** address this, newer versions of SQLite (version 3.3.8 and later) include 439** support for additional result codes that provide more detailed information 440** about errors. The extended result codes are enabled or disabled 441** on a per database connection basis using the 442** [sqlite3_extended_result_codes()] API. 443** 444** Some of the available extended result codes are listed here. 445** One may expect the number of extended result codes will increase 446** over time. Software that uses extended result codes should expect 447** to see new result codes in future releases of SQLite. 448** 449** The SQLITE_OK result code will never be extended. It will always 450** be exactly zero. 451*/ 452#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 453#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 454#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 455#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 456#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 457#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 458#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 459#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 460#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 461#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 462#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 463#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 464#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 465#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 466#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 467#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 468#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 469#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 470#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 471#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 472#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 473#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 474#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 475#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 476#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 477#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 478#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 479#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 480#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 481#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 482#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 483#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 484#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 485#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 486#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 487#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 488#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 489#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 490#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 491#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 492#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 493#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 494#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 495#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 496#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 497#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 498#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 499#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 500#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 501#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 502#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 503#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 504 505/* 506** CAPI3REF: Flags For File Open Operations 507** 508** These bit values are intended for use in the 509** 3rd parameter to the [sqlite3_open_v2()] interface and 510** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 511*/ 512#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 513#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 514#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 515#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 516#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 517#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 518#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 519#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 520#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 521#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 522#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 523#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 524#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 525#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 526#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 527#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 528#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 529#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 530#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 531#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 532 533/* Reserved: 0x00F00000 */ 534 535/* 536** CAPI3REF: Device Characteristics 537** 538** The xDeviceCharacteristics method of the [sqlite3_io_methods] 539** object returns an integer which is a vector of these 540** bit values expressing I/O characteristics of the mass storage 541** device that holds the file that the [sqlite3_io_methods] 542** refers to. 543** 544** The SQLITE_IOCAP_ATOMIC property means that all writes of 545** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 546** mean that writes of blocks that are nnn bytes in size and 547** are aligned to an address which is an integer multiple of 548** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 549** that when data is appended to a file, the data is appended 550** first then the size of the file is extended, never the other 551** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 552** information is written to disk in the same order as calls 553** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 554** after reboot following a crash or power loss, the only bytes in a 555** file that were written at the application level might have changed 556** and that adjacent bytes, even bytes within the same sector are 557** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 558** flag indicate that a file cannot be deleted when open. The 559** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 560** read-only media and cannot be changed even by processes with 561** elevated privileges. 562*/ 563#define SQLITE_IOCAP_ATOMIC 0x00000001 564#define SQLITE_IOCAP_ATOMIC512 0x00000002 565#define SQLITE_IOCAP_ATOMIC1K 0x00000004 566#define SQLITE_IOCAP_ATOMIC2K 0x00000008 567#define SQLITE_IOCAP_ATOMIC4K 0x00000010 568#define SQLITE_IOCAP_ATOMIC8K 0x00000020 569#define SQLITE_IOCAP_ATOMIC16K 0x00000040 570#define SQLITE_IOCAP_ATOMIC32K 0x00000080 571#define SQLITE_IOCAP_ATOMIC64K 0x00000100 572#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 573#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 574#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 575#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 576#define SQLITE_IOCAP_IMMUTABLE 0x00002000 577 578/* 579** CAPI3REF: File Locking Levels 580** 581** SQLite uses one of these integer values as the second 582** argument to calls it makes to the xLock() and xUnlock() methods 583** of an [sqlite3_io_methods] object. 584*/ 585#define SQLITE_LOCK_NONE 0 586#define SQLITE_LOCK_SHARED 1 587#define SQLITE_LOCK_RESERVED 2 588#define SQLITE_LOCK_PENDING 3 589#define SQLITE_LOCK_EXCLUSIVE 4 590 591/* 592** CAPI3REF: Synchronization Type Flags 593** 594** When SQLite invokes the xSync() method of an 595** [sqlite3_io_methods] object it uses a combination of 596** these integer values as the second argument. 597** 598** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 599** sync operation only needs to flush data to mass storage. Inode 600** information need not be flushed. If the lower four bits of the flag 601** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 602** If the lower four bits equal SQLITE_SYNC_FULL, that means 603** to use Mac OS X style fullsync instead of fsync(). 604** 605** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 606** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 607** settings. The [synchronous pragma] determines when calls to the 608** xSync VFS method occur and applies uniformly across all platforms. 609** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 610** energetic or rigorous or forceful the sync operations are and 611** only make a difference on Mac OSX for the default SQLite code. 612** (Third-party VFS implementations might also make the distinction 613** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 614** operating systems natively supported by SQLite, only Mac OSX 615** cares about the difference.) 616*/ 617#define SQLITE_SYNC_NORMAL 0x00002 618#define SQLITE_SYNC_FULL 0x00003 619#define SQLITE_SYNC_DATAONLY 0x00010 620 621/* 622** CAPI3REF: OS Interface Open File Handle 623** 624** An [sqlite3_file] object represents an open file in the 625** [sqlite3_vfs | OS interface layer]. Individual OS interface 626** implementations will 627** want to subclass this object by appending additional fields 628** for their own use. The pMethods entry is a pointer to an 629** [sqlite3_io_methods] object that defines methods for performing 630** I/O operations on the open file. 631*/ 632typedef struct sqlite3_file sqlite3_file; 633struct sqlite3_file { 634 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 635}; 636 637/* 638** CAPI3REF: OS Interface File Virtual Methods Object 639** 640** Every file opened by the [sqlite3_vfs.xOpen] method populates an 641** [sqlite3_file] object (or, more commonly, a subclass of the 642** [sqlite3_file] object) with a pointer to an instance of this object. 643** This object defines the methods used to perform various operations 644** against the open file represented by the [sqlite3_file] object. 645** 646** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 647** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 648** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 649** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 650** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 651** to NULL. 652** 653** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 654** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 655** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 656** flag may be ORed in to indicate that only the data of the file 657** and not its inode needs to be synced. 658** 659** The integer values to xLock() and xUnlock() are one of 660** <ul> 661** <li> [SQLITE_LOCK_NONE], 662** <li> [SQLITE_LOCK_SHARED], 663** <li> [SQLITE_LOCK_RESERVED], 664** <li> [SQLITE_LOCK_PENDING], or 665** <li> [SQLITE_LOCK_EXCLUSIVE]. 666** </ul> 667** xLock() increases the lock. xUnlock() decreases the lock. 668** The xCheckReservedLock() method checks whether any database connection, 669** either in this process or in some other process, is holding a RESERVED, 670** PENDING, or EXCLUSIVE lock on the file. It returns true 671** if such a lock exists and false otherwise. 672** 673** The xFileControl() method is a generic interface that allows custom 674** VFS implementations to directly control an open file using the 675** [sqlite3_file_control()] interface. The second "op" argument is an 676** integer opcode. The third argument is a generic pointer intended to 677** point to a structure that may contain arguments or space in which to 678** write return values. Potential uses for xFileControl() might be 679** functions to enable blocking locks with timeouts, to change the 680** locking strategy (for example to use dot-file locks), to inquire 681** about the status of a lock, or to break stale locks. The SQLite 682** core reserves all opcodes less than 100 for its own use. 683** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 684** Applications that define a custom xFileControl method should use opcodes 685** greater than 100 to avoid conflicts. VFS implementations should 686** return [SQLITE_NOTFOUND] for file control opcodes that they do not 687** recognize. 688** 689** The xSectorSize() method returns the sector size of the 690** device that underlies the file. The sector size is the 691** minimum write that can be performed without disturbing 692** other bytes in the file. The xDeviceCharacteristics() 693** method returns a bit vector describing behaviors of the 694** underlying device: 695** 696** <ul> 697** <li> [SQLITE_IOCAP_ATOMIC] 698** <li> [SQLITE_IOCAP_ATOMIC512] 699** <li> [SQLITE_IOCAP_ATOMIC1K] 700** <li> [SQLITE_IOCAP_ATOMIC2K] 701** <li> [SQLITE_IOCAP_ATOMIC4K] 702** <li> [SQLITE_IOCAP_ATOMIC8K] 703** <li> [SQLITE_IOCAP_ATOMIC16K] 704** <li> [SQLITE_IOCAP_ATOMIC32K] 705** <li> [SQLITE_IOCAP_ATOMIC64K] 706** <li> [SQLITE_IOCAP_SAFE_APPEND] 707** <li> [SQLITE_IOCAP_SEQUENTIAL] 708** </ul> 709** 710** The SQLITE_IOCAP_ATOMIC property means that all writes of 711** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 712** mean that writes of blocks that are nnn bytes in size and 713** are aligned to an address which is an integer multiple of 714** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 715** that when data is appended to a file, the data is appended 716** first then the size of the file is extended, never the other 717** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 718** information is written to disk in the same order as calls 719** to xWrite(). 720** 721** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 722** in the unread portions of the buffer with zeros. A VFS that 723** fails to zero-fill short reads might seem to work. However, 724** failure to zero-fill short reads will eventually lead to 725** database corruption. 726*/ 727typedef struct sqlite3_io_methods sqlite3_io_methods; 728struct sqlite3_io_methods { 729 int iVersion; 730 int (*xClose)(sqlite3_file*); 731 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 732 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 733 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 734 int (*xSync)(sqlite3_file*, int flags); 735 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 736 int (*xLock)(sqlite3_file*, int); 737 int (*xUnlock)(sqlite3_file*, int); 738 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 739 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 740 int (*xSectorSize)(sqlite3_file*); 741 int (*xDeviceCharacteristics)(sqlite3_file*); 742 /* Methods above are valid for version 1 */ 743 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 744 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 745 void (*xShmBarrier)(sqlite3_file*); 746 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 747 /* Methods above are valid for version 2 */ 748 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 749 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 750 /* Methods above are valid for version 3 */ 751 /* Additional methods may be added in future releases */ 752}; 753 754/* 755** CAPI3REF: Standard File Control Opcodes 756** 757** These integer constants are opcodes for the xFileControl method 758** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 759** interface. 760** 761** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 762** opcode causes the xFileControl method to write the current state of 763** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 764** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 765** into an integer that the pArg argument points to. This capability 766** is used during testing and only needs to be supported when SQLITE_TEST 767** is defined. 768** <ul> 769** <li>[[SQLITE_FCNTL_SIZE_HINT]] 770** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 771** layer a hint of how large the database file will grow to be during the 772** current transaction. This hint is not guaranteed to be accurate but it 773** is often close. The underlying VFS might choose to preallocate database 774** file space based on this hint in order to help writes to the database 775** file run faster. 776** 777** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 778** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 779** extends and truncates the database file in chunks of a size specified 780** by the user. The fourth argument to [sqlite3_file_control()] should 781** point to an integer (type int) containing the new chunk-size to use 782** for the nominated database. Allocating database file space in large 783** chunks (say 1MB at a time), may reduce file-system fragmentation and 784** improve performance on some systems. 785** 786** <li>[[SQLITE_FCNTL_FILE_POINTER]] 787** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 788** to the [sqlite3_file] object associated with a particular database 789** connection. See the [sqlite3_file_control()] documentation for 790** additional information. 791** 792** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 793** No longer in use. 794** 795** <li>[[SQLITE_FCNTL_SYNC]] 796** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 797** sent to the VFS immediately before the xSync method is invoked on a 798** database file descriptor. Or, if the xSync method is not invoked 799** because the user has configured SQLite with 800** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 801** of the xSync method. In most cases, the pointer argument passed with 802** this file-control is NULL. However, if the database file is being synced 803** as part of a multi-database commit, the argument points to a nul-terminated 804** string containing the transactions master-journal file name. VFSes that 805** do not need this signal should silently ignore this opcode. Applications 806** should not call [sqlite3_file_control()] with this opcode as doing so may 807** disrupt the operation of the specialized VFSes that do require it. 808** 809** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 810** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 811** and sent to the VFS after a transaction has been committed immediately 812** but before the database is unlocked. VFSes that do not need this signal 813** should silently ignore this opcode. Applications should not call 814** [sqlite3_file_control()] with this opcode as doing so may disrupt the 815** operation of the specialized VFSes that do require it. 816** 817** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 818** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 819** retry counts and intervals for certain disk I/O operations for the 820** windows [VFS] in order to provide robustness in the presence of 821** anti-virus programs. By default, the windows VFS will retry file read, 822** file write, and file delete operations up to 10 times, with a delay 823** of 25 milliseconds before the first retry and with the delay increasing 824** by an additional 25 milliseconds with each subsequent retry. This 825** opcode allows these two values (10 retries and 25 milliseconds of delay) 826** to be adjusted. The values are changed for all database connections 827** within the same process. The argument is a pointer to an array of two 828** integers where the first integer i the new retry count and the second 829** integer is the delay. If either integer is negative, then the setting 830** is not changed but instead the prior value of that setting is written 831** into the array entry, allowing the current retry settings to be 832** interrogated. The zDbName parameter is ignored. 833** 834** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 835** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 836** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 837** write ahead log and shared memory files used for transaction control 838** are automatically deleted when the latest connection to the database 839** closes. Setting persistent WAL mode causes those files to persist after 840** close. Persisting the files is useful when other processes that do not 841** have write permission on the directory containing the database file want 842** to read the database file, as the WAL and shared memory files must exist 843** in order for the database to be readable. The fourth parameter to 844** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 845** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 846** WAL mode. If the integer is -1, then it is overwritten with the current 847** WAL persistence setting. 848** 849** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 850** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 851** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 852** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 853** xDeviceCharacteristics methods. The fourth parameter to 854** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 855** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 856** mode. If the integer is -1, then it is overwritten with the current 857** zero-damage mode setting. 858** 859** <li>[[SQLITE_FCNTL_OVERWRITE]] 860** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 861** a write transaction to indicate that, unless it is rolled back for some 862** reason, the entire database file will be overwritten by the current 863** transaction. This is used by VACUUM operations. 864** 865** <li>[[SQLITE_FCNTL_VFSNAME]] 866** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 867** all [VFSes] in the VFS stack. The names are of all VFS shims and the 868** final bottom-level VFS are written into memory obtained from 869** [sqlite3_malloc()] and the result is stored in the char* variable 870** that the fourth parameter of [sqlite3_file_control()] points to. 871** The caller is responsible for freeing the memory when done. As with 872** all file-control actions, there is no guarantee that this will actually 873** do anything. Callers should initialize the char* variable to a NULL 874** pointer in case this file-control is not implemented. This file-control 875** is intended for diagnostic use only. 876** 877** <li>[[SQLITE_FCNTL_PRAGMA]] 878** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 879** file control is sent to the open [sqlite3_file] object corresponding 880** to the database file to which the pragma statement refers. ^The argument 881** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 882** pointers to strings (char**) in which the second element of the array 883** is the name of the pragma and the third element is the argument to the 884** pragma or NULL if the pragma has no argument. ^The handler for an 885** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 886** of the char** argument point to a string obtained from [sqlite3_mprintf()] 887** or the equivalent and that string will become the result of the pragma or 888** the error message if the pragma fails. ^If the 889** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 890** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 891** file control returns [SQLITE_OK], then the parser assumes that the 892** VFS has handled the PRAGMA itself and the parser generates a no-op 893** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns 894** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 895** that the VFS encountered an error while handling the [PRAGMA] and the 896** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 897** file control occurs at the beginning of pragma statement analysis and so 898** it is able to override built-in [PRAGMA] statements. 899** 900** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 901** ^The [SQLITE_FCNTL_BUSYHANDLER] 902** file-control may be invoked by SQLite on the database file handle 903** shortly after it is opened in order to provide a custom VFS with access 904** to the connections busy-handler callback. The argument is of type (void **) 905** - an array of two (void *) values. The first (void *) actually points 906** to a function of type (int (*)(void *)). In order to invoke the connections 907** busy-handler, this function should be invoked with the second (void *) in 908** the array as the only argument. If it returns non-zero, then the operation 909** should be retried. If it returns zero, the custom VFS should abandon the 910** current operation. 911** 912** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 913** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 914** to have SQLite generate a 915** temporary filename using the same algorithm that is followed to generate 916** temporary filenames for TEMP tables and other internal uses. The 917** argument should be a char** which will be filled with the filename 918** written into memory obtained from [sqlite3_malloc()]. The caller should 919** invoke [sqlite3_free()] on the result to avoid a memory leak. 920** 921** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 922** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 923** maximum number of bytes that will be used for memory-mapped I/O. 924** The argument is a pointer to a value of type sqlite3_int64 that 925** is an advisory maximum number of bytes in the file to memory map. The 926** pointer is overwritten with the old value. The limit is not changed if 927** the value originally pointed to is negative, and so the current limit 928** can be queried by passing in a pointer to a negative number. This 929** file-control is used internally to implement [PRAGMA mmap_size]. 930** 931** <li>[[SQLITE_FCNTL_TRACE]] 932** The [SQLITE_FCNTL_TRACE] file control provides advisory information 933** to the VFS about what the higher layers of the SQLite stack are doing. 934** This file control is used by some VFS activity tracing [shims]. 935** The argument is a zero-terminated string. Higher layers in the 936** SQLite stack may generate instances of this file control if 937** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 938** 939** <li>[[SQLITE_FCNTL_HAS_MOVED]] 940** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 941** pointer to an integer and it writes a boolean into that integer depending 942** on whether or not the file has been renamed, moved, or deleted since it 943** was first opened. 944** 945** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 946** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 947** opcode causes the xFileControl method to swap the file handle with the one 948** pointed to by the pArg argument. This capability is used during testing 949** and only needs to be supported when SQLITE_TEST is defined. 950** 951** </ul> 952*/ 953#define SQLITE_FCNTL_LOCKSTATE 1 954#define SQLITE_GET_LOCKPROXYFILE 2 955#define SQLITE_SET_LOCKPROXYFILE 3 956#define SQLITE_LAST_ERRNO 4 957#define SQLITE_FCNTL_SIZE_HINT 5 958#define SQLITE_FCNTL_CHUNK_SIZE 6 959#define SQLITE_FCNTL_FILE_POINTER 7 960#define SQLITE_FCNTL_SYNC_OMITTED 8 961#define SQLITE_FCNTL_WIN32_AV_RETRY 9 962#define SQLITE_FCNTL_PERSIST_WAL 10 963#define SQLITE_FCNTL_OVERWRITE 11 964#define SQLITE_FCNTL_VFSNAME 12 965#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 966#define SQLITE_FCNTL_PRAGMA 14 967#define SQLITE_FCNTL_BUSYHANDLER 15 968#define SQLITE_FCNTL_TEMPFILENAME 16 969#define SQLITE_FCNTL_MMAP_SIZE 18 970#define SQLITE_FCNTL_TRACE 19 971#define SQLITE_FCNTL_HAS_MOVED 20 972#define SQLITE_FCNTL_SYNC 21 973#define SQLITE_FCNTL_COMMIT_PHASETWO 22 974#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 975 976/* 977** CAPI3REF: Mutex Handle 978** 979** The mutex module within SQLite defines [sqlite3_mutex] to be an 980** abstract type for a mutex object. The SQLite core never looks 981** at the internal representation of an [sqlite3_mutex]. It only 982** deals with pointers to the [sqlite3_mutex] object. 983** 984** Mutexes are created using [sqlite3_mutex_alloc()]. 985*/ 986typedef struct sqlite3_mutex sqlite3_mutex; 987 988/* 989** CAPI3REF: OS Interface Object 990** 991** An instance of the sqlite3_vfs object defines the interface between 992** the SQLite core and the underlying operating system. The "vfs" 993** in the name of the object stands for "virtual file system". See 994** the [VFS | VFS documentation] for further information. 995** 996** The value of the iVersion field is initially 1 but may be larger in 997** future versions of SQLite. Additional fields may be appended to this 998** object when the iVersion value is increased. Note that the structure 999** of the sqlite3_vfs object changes in the transaction between 1000** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1001** modified. 1002** 1003** The szOsFile field is the size of the subclassed [sqlite3_file] 1004** structure used by this VFS. mxPathname is the maximum length of 1005** a pathname in this VFS. 1006** 1007** Registered sqlite3_vfs objects are kept on a linked list formed by 1008** the pNext pointer. The [sqlite3_vfs_register()] 1009** and [sqlite3_vfs_unregister()] interfaces manage this list 1010** in a thread-safe way. The [sqlite3_vfs_find()] interface 1011** searches the list. Neither the application code nor the VFS 1012** implementation should use the pNext pointer. 1013** 1014** The pNext field is the only field in the sqlite3_vfs 1015** structure that SQLite will ever modify. SQLite will only access 1016** or modify this field while holding a particular static mutex. 1017** The application should never modify anything within the sqlite3_vfs 1018** object once the object has been registered. 1019** 1020** The zName field holds the name of the VFS module. The name must 1021** be unique across all VFS modules. 1022** 1023** [[sqlite3_vfs.xOpen]] 1024** ^SQLite guarantees that the zFilename parameter to xOpen 1025** is either a NULL pointer or string obtained 1026** from xFullPathname() with an optional suffix added. 1027** ^If a suffix is added to the zFilename parameter, it will 1028** consist of a single "-" character followed by no more than 1029** 11 alphanumeric and/or "-" characters. 1030** ^SQLite further guarantees that 1031** the string will be valid and unchanged until xClose() is 1032** called. Because of the previous sentence, 1033** the [sqlite3_file] can safely store a pointer to the 1034** filename if it needs to remember the filename for some reason. 1035** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1036** must invent its own temporary name for the file. ^Whenever the 1037** xFilename parameter is NULL it will also be the case that the 1038** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1039** 1040** The flags argument to xOpen() includes all bits set in 1041** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1042** or [sqlite3_open16()] is used, then flags includes at least 1043** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1044** If xOpen() opens a file read-only then it sets *pOutFlags to 1045** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1046** 1047** ^(SQLite will also add one of the following flags to the xOpen() 1048** call, depending on the object being opened: 1049** 1050** <ul> 1051** <li> [SQLITE_OPEN_MAIN_DB] 1052** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1053** <li> [SQLITE_OPEN_TEMP_DB] 1054** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1055** <li> [SQLITE_OPEN_TRANSIENT_DB] 1056** <li> [SQLITE_OPEN_SUBJOURNAL] 1057** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1058** <li> [SQLITE_OPEN_WAL] 1059** </ul>)^ 1060** 1061** The file I/O implementation can use the object type flags to 1062** change the way it deals with files. For example, an application 1063** that does not care about crash recovery or rollback might make 1064** the open of a journal file a no-op. Writes to this journal would 1065** also be no-ops, and any attempt to read the journal would return 1066** SQLITE_IOERR. Or the implementation might recognize that a database 1067** file will be doing page-aligned sector reads and writes in a random 1068** order and set up its I/O subsystem accordingly. 1069** 1070** SQLite might also add one of the following flags to the xOpen method: 1071** 1072** <ul> 1073** <li> [SQLITE_OPEN_DELETEONCLOSE] 1074** <li> [SQLITE_OPEN_EXCLUSIVE] 1075** </ul> 1076** 1077** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1078** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1079** will be set for TEMP databases and their journals, transient 1080** databases, and subjournals. 1081** 1082** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1083** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1084** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1085** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1086** SQLITE_OPEN_CREATE, is used to indicate that file should always 1087** be created, and that it is an error if it already exists. 1088** It is <i>not</i> used to indicate the file should be opened 1089** for exclusive access. 1090** 1091** ^At least szOsFile bytes of memory are allocated by SQLite 1092** to hold the [sqlite3_file] structure passed as the third 1093** argument to xOpen. The xOpen method does not have to 1094** allocate the structure; it should just fill it in. Note that 1095** the xOpen method must set the sqlite3_file.pMethods to either 1096** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1097** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1098** element will be valid after xOpen returns regardless of the success 1099** or failure of the xOpen call. 1100** 1101** [[sqlite3_vfs.xAccess]] 1102** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1103** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1104** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1105** to test whether a file is at least readable. The file can be a 1106** directory. 1107** 1108** ^SQLite will always allocate at least mxPathname+1 bytes for the 1109** output buffer xFullPathname. The exact size of the output buffer 1110** is also passed as a parameter to both methods. If the output buffer 1111** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1112** handled as a fatal error by SQLite, vfs implementations should endeavor 1113** to prevent this by setting mxPathname to a sufficiently large value. 1114** 1115** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1116** interfaces are not strictly a part of the filesystem, but they are 1117** included in the VFS structure for completeness. 1118** The xRandomness() function attempts to return nBytes bytes 1119** of good-quality randomness into zOut. The return value is 1120** the actual number of bytes of randomness obtained. 1121** The xSleep() method causes the calling thread to sleep for at 1122** least the number of microseconds given. ^The xCurrentTime() 1123** method returns a Julian Day Number for the current date and time as 1124** a floating point value. 1125** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1126** Day Number multiplied by 86400000 (the number of milliseconds in 1127** a 24-hour day). 1128** ^SQLite will use the xCurrentTimeInt64() method to get the current 1129** date and time if that method is available (if iVersion is 2 or 1130** greater and the function pointer is not NULL) and will fall back 1131** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1132** 1133** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1134** are not used by the SQLite core. These optional interfaces are provided 1135** by some VFSes to facilitate testing of the VFS code. By overriding 1136** system calls with functions under its control, a test program can 1137** simulate faults and error conditions that would otherwise be difficult 1138** or impossible to induce. The set of system calls that can be overridden 1139** varies from one VFS to another, and from one version of the same VFS to the 1140** next. Applications that use these interfaces must be prepared for any 1141** or all of these interfaces to be NULL or for their behavior to change 1142** from one release to the next. Applications must not attempt to access 1143** any of these methods if the iVersion of the VFS is less than 3. 1144*/ 1145typedef struct sqlite3_vfs sqlite3_vfs; 1146typedef void (*sqlite3_syscall_ptr)(void); 1147struct sqlite3_vfs { 1148 int iVersion; /* Structure version number (currently 3) */ 1149 int szOsFile; /* Size of subclassed sqlite3_file */ 1150 int mxPathname; /* Maximum file pathname length */ 1151 sqlite3_vfs *pNext; /* Next registered VFS */ 1152 const char *zName; /* Name of this virtual file system */ 1153 void *pAppData; /* Pointer to application-specific data */ 1154 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1155 int flags, int *pOutFlags); 1156 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1157 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1158 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1159 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1160 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1161 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1162 void (*xDlClose)(sqlite3_vfs*, void*); 1163 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1164 int (*xSleep)(sqlite3_vfs*, int microseconds); 1165 int (*xCurrentTime)(sqlite3_vfs*, double*); 1166 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1167 /* 1168 ** The methods above are in version 1 of the sqlite_vfs object 1169 ** definition. Those that follow are added in version 2 or later 1170 */ 1171 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1172 /* 1173 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1174 ** Those below are for version 3 and greater. 1175 */ 1176 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1177 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1178 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1179 /* 1180 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1181 ** New fields may be appended in figure versions. The iVersion 1182 ** value will increment whenever this happens. 1183 */ 1184}; 1185 1186/* 1187** CAPI3REF: Flags for the xAccess VFS method 1188** 1189** These integer constants can be used as the third parameter to 1190** the xAccess method of an [sqlite3_vfs] object. They determine 1191** what kind of permissions the xAccess method is looking for. 1192** With SQLITE_ACCESS_EXISTS, the xAccess method 1193** simply checks whether the file exists. 1194** With SQLITE_ACCESS_READWRITE, the xAccess method 1195** checks whether the named directory is both readable and writable 1196** (in other words, if files can be added, removed, and renamed within 1197** the directory). 1198** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1199** [temp_store_directory pragma], though this could change in a future 1200** release of SQLite. 1201** With SQLITE_ACCESS_READ, the xAccess method 1202** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1203** currently unused, though it might be used in a future release of 1204** SQLite. 1205*/ 1206#define SQLITE_ACCESS_EXISTS 0 1207#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1208#define SQLITE_ACCESS_READ 2 /* Unused */ 1209 1210/* 1211** CAPI3REF: Flags for the xShmLock VFS method 1212** 1213** These integer constants define the various locking operations 1214** allowed by the xShmLock method of [sqlite3_io_methods]. The 1215** following are the only legal combinations of flags to the 1216** xShmLock method: 1217** 1218** <ul> 1219** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1220** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1221** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1222** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1223** </ul> 1224** 1225** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1226** was given no the corresponding lock. 1227** 1228** The xShmLock method can transition between unlocked and SHARED or 1229** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1230** and EXCLUSIVE. 1231*/ 1232#define SQLITE_SHM_UNLOCK 1 1233#define SQLITE_SHM_LOCK 2 1234#define SQLITE_SHM_SHARED 4 1235#define SQLITE_SHM_EXCLUSIVE 8 1236 1237/* 1238** CAPI3REF: Maximum xShmLock index 1239** 1240** The xShmLock method on [sqlite3_io_methods] may use values 1241** between 0 and this upper bound as its "offset" argument. 1242** The SQLite core will never attempt to acquire or release a 1243** lock outside of this range 1244*/ 1245#define SQLITE_SHM_NLOCK 8 1246 1247 1248/* 1249** CAPI3REF: Initialize The SQLite Library 1250** 1251** ^The sqlite3_initialize() routine initializes the 1252** SQLite library. ^The sqlite3_shutdown() routine 1253** deallocates any resources that were allocated by sqlite3_initialize(). 1254** These routines are designed to aid in process initialization and 1255** shutdown on embedded systems. Workstation applications using 1256** SQLite normally do not need to invoke either of these routines. 1257** 1258** A call to sqlite3_initialize() is an "effective" call if it is 1259** the first time sqlite3_initialize() is invoked during the lifetime of 1260** the process, or if it is the first time sqlite3_initialize() is invoked 1261** following a call to sqlite3_shutdown(). ^(Only an effective call 1262** of sqlite3_initialize() does any initialization. All other calls 1263** are harmless no-ops.)^ 1264** 1265** A call to sqlite3_shutdown() is an "effective" call if it is the first 1266** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1267** an effective call to sqlite3_shutdown() does any deinitialization. 1268** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1269** 1270** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1271** is not. The sqlite3_shutdown() interface must only be called from a 1272** single thread. All open [database connections] must be closed and all 1273** other SQLite resources must be deallocated prior to invoking 1274** sqlite3_shutdown(). 1275** 1276** Among other things, ^sqlite3_initialize() will invoke 1277** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1278** will invoke sqlite3_os_end(). 1279** 1280** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1281** ^If for some reason, sqlite3_initialize() is unable to initialize 1282** the library (perhaps it is unable to allocate a needed resource such 1283** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1284** 1285** ^The sqlite3_initialize() routine is called internally by many other 1286** SQLite interfaces so that an application usually does not need to 1287** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1288** calls sqlite3_initialize() so the SQLite library will be automatically 1289** initialized when [sqlite3_open()] is called if it has not be initialized 1290** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1291** compile-time option, then the automatic calls to sqlite3_initialize() 1292** are omitted and the application must call sqlite3_initialize() directly 1293** prior to using any other SQLite interface. For maximum portability, 1294** it is recommended that applications always invoke sqlite3_initialize() 1295** directly prior to using any other SQLite interface. Future releases 1296** of SQLite may require this. In other words, the behavior exhibited 1297** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1298** default behavior in some future release of SQLite. 1299** 1300** The sqlite3_os_init() routine does operating-system specific 1301** initialization of the SQLite library. The sqlite3_os_end() 1302** routine undoes the effect of sqlite3_os_init(). Typical tasks 1303** performed by these routines include allocation or deallocation 1304** of static resources, initialization of global variables, 1305** setting up a default [sqlite3_vfs] module, or setting up 1306** a default configuration using [sqlite3_config()]. 1307** 1308** The application should never invoke either sqlite3_os_init() 1309** or sqlite3_os_end() directly. The application should only invoke 1310** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1311** interface is called automatically by sqlite3_initialize() and 1312** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1313** implementations for sqlite3_os_init() and sqlite3_os_end() 1314** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1315** When [custom builds | built for other platforms] 1316** (using the [SQLITE_OS_OTHER=1] compile-time 1317** option) the application must supply a suitable implementation for 1318** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1319** implementation of sqlite3_os_init() or sqlite3_os_end() 1320** must return [SQLITE_OK] on success and some other [error code] upon 1321** failure. 1322*/ 1323int sqlite3_initialize(void); 1324int sqlite3_shutdown(void); 1325int sqlite3_os_init(void); 1326int sqlite3_os_end(void); 1327 1328/* 1329** CAPI3REF: Configuring The SQLite Library 1330** 1331** The sqlite3_config() interface is used to make global configuration 1332** changes to SQLite in order to tune SQLite to the specific needs of 1333** the application. The default configuration is recommended for most 1334** applications and so this routine is usually not necessary. It is 1335** provided to support rare applications with unusual needs. 1336** 1337** The sqlite3_config() interface is not threadsafe. The application 1338** must insure that no other SQLite interfaces are invoked by other 1339** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1340** may only be invoked prior to library initialization using 1341** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1342** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1343** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1344** Note, however, that ^sqlite3_config() can be called as part of the 1345** implementation of an application-defined [sqlite3_os_init()]. 1346** 1347** The first argument to sqlite3_config() is an integer 1348** [configuration option] that determines 1349** what property of SQLite is to be configured. Subsequent arguments 1350** vary depending on the [configuration option] 1351** in the first argument. 1352** 1353** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1354** ^If the option is unknown or SQLite is unable to set the option 1355** then this routine returns a non-zero [error code]. 1356*/ 1357int sqlite3_config(int, ...); 1358 1359/* 1360** CAPI3REF: Configure database connections 1361** 1362** The sqlite3_db_config() interface is used to make configuration 1363** changes to a [database connection]. The interface is similar to 1364** [sqlite3_config()] except that the changes apply to a single 1365** [database connection] (specified in the first argument). 1366** 1367** The second argument to sqlite3_db_config(D,V,...) is the 1368** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1369** that indicates what aspect of the [database connection] is being configured. 1370** Subsequent arguments vary depending on the configuration verb. 1371** 1372** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1373** the call is considered successful. 1374*/ 1375int sqlite3_db_config(sqlite3*, int op, ...); 1376 1377/* 1378** CAPI3REF: Memory Allocation Routines 1379** 1380** An instance of this object defines the interface between SQLite 1381** and low-level memory allocation routines. 1382** 1383** This object is used in only one place in the SQLite interface. 1384** A pointer to an instance of this object is the argument to 1385** [sqlite3_config()] when the configuration option is 1386** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1387** By creating an instance of this object 1388** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1389** during configuration, an application can specify an alternative 1390** memory allocation subsystem for SQLite to use for all of its 1391** dynamic memory needs. 1392** 1393** Note that SQLite comes with several [built-in memory allocators] 1394** that are perfectly adequate for the overwhelming majority of applications 1395** and that this object is only useful to a tiny minority of applications 1396** with specialized memory allocation requirements. This object is 1397** also used during testing of SQLite in order to specify an alternative 1398** memory allocator that simulates memory out-of-memory conditions in 1399** order to verify that SQLite recovers gracefully from such 1400** conditions. 1401** 1402** The xMalloc, xRealloc, and xFree methods must work like the 1403** malloc(), realloc() and free() functions from the standard C library. 1404** ^SQLite guarantees that the second argument to 1405** xRealloc is always a value returned by a prior call to xRoundup. 1406** 1407** xSize should return the allocated size of a memory allocation 1408** previously obtained from xMalloc or xRealloc. The allocated size 1409** is always at least as big as the requested size but may be larger. 1410** 1411** The xRoundup method returns what would be the allocated size of 1412** a memory allocation given a particular requested size. Most memory 1413** allocators round up memory allocations at least to the next multiple 1414** of 8. Some allocators round up to a larger multiple or to a power of 2. 1415** Every memory allocation request coming in through [sqlite3_malloc()] 1416** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1417** that causes the corresponding memory allocation to fail. 1418** 1419** The xInit method initializes the memory allocator. For example, 1420** it might allocate any require mutexes or initialize internal data 1421** structures. The xShutdown method is invoked (indirectly) by 1422** [sqlite3_shutdown()] and should deallocate any resources acquired 1423** by xInit. The pAppData pointer is used as the only parameter to 1424** xInit and xShutdown. 1425** 1426** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1427** the xInit method, so the xInit method need not be threadsafe. The 1428** xShutdown method is only called from [sqlite3_shutdown()] so it does 1429** not need to be threadsafe either. For all other methods, SQLite 1430** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1431** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1432** it is by default) and so the methods are automatically serialized. 1433** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1434** methods must be threadsafe or else make their own arrangements for 1435** serialization. 1436** 1437** SQLite will never invoke xInit() more than once without an intervening 1438** call to xShutdown(). 1439*/ 1440typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1441struct sqlite3_mem_methods { 1442 void *(*xMalloc)(int); /* Memory allocation function */ 1443 void (*xFree)(void*); /* Free a prior allocation */ 1444 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1445 int (*xSize)(void*); /* Return the size of an allocation */ 1446 int (*xRoundup)(int); /* Round up request size to allocation size */ 1447 int (*xInit)(void*); /* Initialize the memory allocator */ 1448 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1449 void *pAppData; /* Argument to xInit() and xShutdown() */ 1450}; 1451 1452/* 1453** CAPI3REF: Configuration Options 1454** KEYWORDS: {configuration option} 1455** 1456** These constants are the available integer configuration options that 1457** can be passed as the first argument to the [sqlite3_config()] interface. 1458** 1459** New configuration options may be added in future releases of SQLite. 1460** Existing configuration options might be discontinued. Applications 1461** should check the return code from [sqlite3_config()] to make sure that 1462** the call worked. The [sqlite3_config()] interface will return a 1463** non-zero [error code] if a discontinued or unsupported configuration option 1464** is invoked. 1465** 1466** <dl> 1467** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1468** <dd>There are no arguments to this option. ^This option sets the 1469** [threading mode] to Single-thread. In other words, it disables 1470** all mutexing and puts SQLite into a mode where it can only be used 1471** by a single thread. ^If SQLite is compiled with 1472** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1473** it is not possible to change the [threading mode] from its default 1474** value of Single-thread and so [sqlite3_config()] will return 1475** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1476** configuration option.</dd> 1477** 1478** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1479** <dd>There are no arguments to this option. ^This option sets the 1480** [threading mode] to Multi-thread. In other words, it disables 1481** mutexing on [database connection] and [prepared statement] objects. 1482** The application is responsible for serializing access to 1483** [database connections] and [prepared statements]. But other mutexes 1484** are enabled so that SQLite will be safe to use in a multi-threaded 1485** environment as long as no two threads attempt to use the same 1486** [database connection] at the same time. ^If SQLite is compiled with 1487** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1488** it is not possible to set the Multi-thread [threading mode] and 1489** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1490** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1491** 1492** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1493** <dd>There are no arguments to this option. ^This option sets the 1494** [threading mode] to Serialized. In other words, this option enables 1495** all mutexes including the recursive 1496** mutexes on [database connection] and [prepared statement] objects. 1497** In this mode (which is the default when SQLite is compiled with 1498** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1499** to [database connections] and [prepared statements] so that the 1500** application is free to use the same [database connection] or the 1501** same [prepared statement] in different threads at the same time. 1502** ^If SQLite is compiled with 1503** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1504** it is not possible to set the Serialized [threading mode] and 1505** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1506** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1507** 1508** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1509** <dd> ^(This option takes a single argument which is a pointer to an 1510** instance of the [sqlite3_mem_methods] structure. The argument specifies 1511** alternative low-level memory allocation routines to be used in place of 1512** the memory allocation routines built into SQLite.)^ ^SQLite makes 1513** its own private copy of the content of the [sqlite3_mem_methods] structure 1514** before the [sqlite3_config()] call returns.</dd> 1515** 1516** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1517** <dd> ^(This option takes a single argument which is a pointer to an 1518** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1519** structure is filled with the currently defined memory allocation routines.)^ 1520** This option can be used to overload the default memory allocation 1521** routines with a wrapper that simulations memory allocation failure or 1522** tracks memory usage, for example. </dd> 1523** 1524** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1525** <dd> ^This option takes single argument of type int, interpreted as a 1526** boolean, which enables or disables the collection of memory allocation 1527** statistics. ^(When memory allocation statistics are disabled, the 1528** following SQLite interfaces become non-operational: 1529** <ul> 1530** <li> [sqlite3_memory_used()] 1531** <li> [sqlite3_memory_highwater()] 1532** <li> [sqlite3_soft_heap_limit64()] 1533** <li> [sqlite3_status()] 1534** </ul>)^ 1535** ^Memory allocation statistics are enabled by default unless SQLite is 1536** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1537** allocation statistics are disabled by default. 1538** </dd> 1539** 1540** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1541** <dd> ^This option specifies a static memory buffer that SQLite can use for 1542** scratch memory. There are three arguments: A pointer an 8-byte 1543** aligned memory buffer from which the scratch allocations will be 1544** drawn, the size of each scratch allocation (sz), 1545** and the maximum number of scratch allocations (N). The sz 1546** argument must be a multiple of 16. 1547** The first argument must be a pointer to an 8-byte aligned buffer 1548** of at least sz*N bytes of memory. 1549** ^SQLite will use no more than two scratch buffers per thread. So 1550** N should be set to twice the expected maximum number of threads. 1551** ^SQLite will never require a scratch buffer that is more than 6 1552** times the database page size. ^If SQLite needs needs additional 1553** scratch memory beyond what is provided by this configuration option, then 1554** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1555** 1556** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1557** <dd> ^This option specifies a static memory buffer that SQLite can use for 1558** the database page cache with the default page cache implementation. 1559** This configuration should not be used if an application-define page 1560** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option. 1561** There are three arguments to this option: A pointer to 8-byte aligned 1562** memory, the size of each page buffer (sz), and the number of pages (N). 1563** The sz argument should be the size of the largest database page 1564** (a power of two between 512 and 32768) plus a little extra for each 1565** page header. ^The page header size is 20 to 40 bytes depending on 1566** the host architecture. ^It is harmless, apart from the wasted memory, 1567** to make sz a little too large. The first 1568** argument should point to an allocation of at least sz*N bytes of memory. 1569** ^SQLite will use the memory provided by the first argument to satisfy its 1570** memory needs for the first N pages that it adds to cache. ^If additional 1571** page cache memory is needed beyond what is provided by this option, then 1572** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1573** The pointer in the first argument must 1574** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1575** will be undefined.</dd> 1576** 1577** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1578** <dd> ^This option specifies a static memory buffer that SQLite will use 1579** for all of its dynamic memory allocation needs beyond those provided 1580** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1581** There are three arguments: An 8-byte aligned pointer to the memory, 1582** the number of bytes in the memory buffer, and the minimum allocation size. 1583** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1584** to using its default memory allocator (the system malloc() implementation), 1585** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1586** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1587** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1588** allocator is engaged to handle all of SQLites memory allocation needs. 1589** The first pointer (the memory pointer) must be aligned to an 8-byte 1590** boundary or subsequent behavior of SQLite will be undefined. 1591** The minimum allocation size is capped at 2**12. Reasonable values 1592** for the minimum allocation size are 2**5 through 2**8.</dd> 1593** 1594** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1595** <dd> ^(This option takes a single argument which is a pointer to an 1596** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1597** alternative low-level mutex routines to be used in place 1598** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1599** content of the [sqlite3_mutex_methods] structure before the call to 1600** [sqlite3_config()] returns. ^If SQLite is compiled with 1601** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1602** the entire mutexing subsystem is omitted from the build and hence calls to 1603** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1604** return [SQLITE_ERROR].</dd> 1605** 1606** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1607** <dd> ^(This option takes a single argument which is a pointer to an 1608** instance of the [sqlite3_mutex_methods] structure. The 1609** [sqlite3_mutex_methods] 1610** structure is filled with the currently defined mutex routines.)^ 1611** This option can be used to overload the default mutex allocation 1612** routines with a wrapper used to track mutex usage for performance 1613** profiling or testing, for example. ^If SQLite is compiled with 1614** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1615** the entire mutexing subsystem is omitted from the build and hence calls to 1616** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1617** return [SQLITE_ERROR].</dd> 1618** 1619** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1620** <dd> ^(This option takes two arguments that determine the default 1621** memory allocation for the lookaside memory allocator on each 1622** [database connection]. The first argument is the 1623** size of each lookaside buffer slot and the second is the number of 1624** slots allocated to each database connection.)^ ^(This option sets the 1625** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1626** verb to [sqlite3_db_config()] can be used to change the lookaside 1627** configuration on individual connections.)^ </dd> 1628** 1629** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1630** <dd> ^(This option takes a single argument which is a pointer to 1631** an [sqlite3_pcache_methods2] object. This object specifies the interface 1632** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1633** object and uses it for page cache memory allocations.</dd> 1634** 1635** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1636** <dd> ^(This option takes a single argument which is a pointer to an 1637** [sqlite3_pcache_methods2] object. SQLite copies of the current 1638** page cache implementation into that object.)^ </dd> 1639** 1640** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1641** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1642** global [error log]. 1643** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1644** function with a call signature of void(*)(void*,int,const char*), 1645** and a pointer to void. ^If the function pointer is not NULL, it is 1646** invoked by [sqlite3_log()] to process each logging event. ^If the 1647** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1648** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1649** passed through as the first parameter to the application-defined logger 1650** function whenever that function is invoked. ^The second parameter to 1651** the logger function is a copy of the first parameter to the corresponding 1652** [sqlite3_log()] call and is intended to be a [result code] or an 1653** [extended result code]. ^The third parameter passed to the logger is 1654** log message after formatting via [sqlite3_snprintf()]. 1655** The SQLite logging interface is not reentrant; the logger function 1656** supplied by the application must not invoke any SQLite interface. 1657** In a multi-threaded application, the application-defined logger 1658** function must be threadsafe. </dd> 1659** 1660** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1661** <dd>^(This option takes a single argument of type int. If non-zero, then 1662** URI handling is globally enabled. If the parameter is zero, then URI handling 1663** is globally disabled.)^ ^If URI handling is globally enabled, all filenames 1664** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1665** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1666** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1667** connection is opened. ^If it is globally disabled, filenames are 1668** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1669** database connection is opened. ^(By default, URI handling is globally 1670** disabled. The default value may be changed by compiling with the 1671** [SQLITE_USE_URI] symbol defined.)^ 1672** 1673** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1674** <dd>^This option takes a single integer argument which is interpreted as 1675** a boolean in order to enable or disable the use of covering indices for 1676** full table scans in the query optimizer. ^The default setting is determined 1677** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1678** if that compile-time option is omitted. 1679** The ability to disable the use of covering indices for full table scans 1680** is because some incorrectly coded legacy applications might malfunction 1681** when the optimization is enabled. Providing the ability to 1682** disable the optimization allows the older, buggy application code to work 1683** without change even with newer versions of SQLite. 1684** 1685** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1686** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1687** <dd> These options are obsolete and should not be used by new code. 1688** They are retained for backwards compatibility but are now no-ops. 1689** </dd> 1690** 1691** [[SQLITE_CONFIG_SQLLOG]] 1692** <dt>SQLITE_CONFIG_SQLLOG 1693** <dd>This option is only available if sqlite is compiled with the 1694** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1695** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1696** The second should be of type (void*). The callback is invoked by the library 1697** in three separate circumstances, identified by the value passed as the 1698** fourth parameter. If the fourth parameter is 0, then the database connection 1699** passed as the second argument has just been opened. The third argument 1700** points to a buffer containing the name of the main database file. If the 1701** fourth parameter is 1, then the SQL statement that the third parameter 1702** points to has just been executed. Or, if the fourth parameter is 2, then 1703** the connection being passed as the second parameter is being closed. The 1704** third parameter is passed NULL In this case. An example of using this 1705** configuration option can be seen in the "test_sqllog.c" source file in 1706** the canonical SQLite source tree.</dd> 1707** 1708** [[SQLITE_CONFIG_MMAP_SIZE]] 1709** <dt>SQLITE_CONFIG_MMAP_SIZE 1710** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1711** that are the default mmap size limit (the default setting for 1712** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1713** ^The default setting can be overridden by each database connection using 1714** either the [PRAGMA mmap_size] command, or by using the 1715** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1716** cannot be changed at run-time. Nor may the maximum allowed mmap size 1717** exceed the compile-time maximum mmap size set by the 1718** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1719** ^If either argument to this option is negative, then that argument is 1720** changed to its compile-time default. 1721** 1722** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1723** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1724** <dd>^This option is only available if SQLite is compiled for Windows 1725** with the [SQLITE_WIN32_MALLOC] pre-processor macro defined. 1726** SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1727** that specifies the maximum size of the created heap. 1728** </dl> 1729*/ 1730#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1731#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1732#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1733#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1734#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1735#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1736#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1737#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1738#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1739#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1740#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1741/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1742#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1743#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1744#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1745#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1746#define SQLITE_CONFIG_URI 17 /* int */ 1747#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1748#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1749#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1750#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1751#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1752#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1753 1754/* 1755** CAPI3REF: Database Connection Configuration Options 1756** 1757** These constants are the available integer configuration options that 1758** can be passed as the second argument to the [sqlite3_db_config()] interface. 1759** 1760** New configuration options may be added in future releases of SQLite. 1761** Existing configuration options might be discontinued. Applications 1762** should check the return code from [sqlite3_db_config()] to make sure that 1763** the call worked. ^The [sqlite3_db_config()] interface will return a 1764** non-zero [error code] if a discontinued or unsupported configuration option 1765** is invoked. 1766** 1767** <dl> 1768** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1769** <dd> ^This option takes three additional arguments that determine the 1770** [lookaside memory allocator] configuration for the [database connection]. 1771** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1772** pointer to a memory buffer to use for lookaside memory. 1773** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1774** may be NULL in which case SQLite will allocate the 1775** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1776** size of each lookaside buffer slot. ^The third argument is the number of 1777** slots. The size of the buffer in the first argument must be greater than 1778** or equal to the product of the second and third arguments. The buffer 1779** must be aligned to an 8-byte boundary. ^If the second argument to 1780** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1781** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1782** configuration for a database connection can only be changed when that 1783** connection is not currently using lookaside memory, or in other words 1784** when the "current value" returned by 1785** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1786** Any attempt to change the lookaside memory configuration when lookaside 1787** memory is in use leaves the configuration unchanged and returns 1788** [SQLITE_BUSY].)^</dd> 1789** 1790** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1791** <dd> ^This option is used to enable or disable the enforcement of 1792** [foreign key constraints]. There should be two additional arguments. 1793** The first argument is an integer which is 0 to disable FK enforcement, 1794** positive to enable FK enforcement or negative to leave FK enforcement 1795** unchanged. The second parameter is a pointer to an integer into which 1796** is written 0 or 1 to indicate whether FK enforcement is off or on 1797** following this call. The second parameter may be a NULL pointer, in 1798** which case the FK enforcement setting is not reported back. </dd> 1799** 1800** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1801** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1802** There should be two additional arguments. 1803** The first argument is an integer which is 0 to disable triggers, 1804** positive to enable triggers or negative to leave the setting unchanged. 1805** The second parameter is a pointer to an integer into which 1806** is written 0 or 1 to indicate whether triggers are disabled or enabled 1807** following this call. The second parameter may be a NULL pointer, in 1808** which case the trigger setting is not reported back. </dd> 1809** 1810** </dl> 1811*/ 1812#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1813#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1814#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1815 1816 1817/* 1818** CAPI3REF: Enable Or Disable Extended Result Codes 1819** 1820** ^The sqlite3_extended_result_codes() routine enables or disables the 1821** [extended result codes] feature of SQLite. ^The extended result 1822** codes are disabled by default for historical compatibility. 1823*/ 1824int sqlite3_extended_result_codes(sqlite3*, int onoff); 1825 1826/* 1827** CAPI3REF: Last Insert Rowid 1828** 1829** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 1830** has a unique 64-bit signed 1831** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1832** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1833** names are not also used by explicitly declared columns. ^If 1834** the table has a column of type [INTEGER PRIMARY KEY] then that column 1835** is another alias for the rowid. 1836** 1837** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the 1838** most recent successful [INSERT] into a rowid table or [virtual table] 1839** on database connection D. 1840** ^Inserts into [WITHOUT ROWID] tables are not recorded. 1841** ^If no successful [INSERT]s into rowid tables 1842** have ever occurred on the database connection D, 1843** then sqlite3_last_insert_rowid(D) returns zero. 1844** 1845** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1846** method, then this routine will return the [rowid] of the inserted 1847** row as long as the trigger or virtual table method is running. 1848** But once the trigger or virtual table method ends, the value returned 1849** by this routine reverts to what it was before the trigger or virtual 1850** table method began.)^ 1851** 1852** ^An [INSERT] that fails due to a constraint violation is not a 1853** successful [INSERT] and does not change the value returned by this 1854** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1855** and INSERT OR ABORT make no changes to the return value of this 1856** routine when their insertion fails. ^(When INSERT OR REPLACE 1857** encounters a constraint violation, it does not fail. The 1858** INSERT continues to completion after deleting rows that caused 1859** the constraint problem so INSERT OR REPLACE will always change 1860** the return value of this interface.)^ 1861** 1862** ^For the purposes of this routine, an [INSERT] is considered to 1863** be successful even if it is subsequently rolled back. 1864** 1865** This function is accessible to SQL statements via the 1866** [last_insert_rowid() SQL function]. 1867** 1868** If a separate thread performs a new [INSERT] on the same 1869** database connection while the [sqlite3_last_insert_rowid()] 1870** function is running and thus changes the last insert [rowid], 1871** then the value returned by [sqlite3_last_insert_rowid()] is 1872** unpredictable and might not equal either the old or the new 1873** last insert [rowid]. 1874*/ 1875sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1876 1877/* 1878** CAPI3REF: Count The Number Of Rows Modified 1879** 1880** ^This function returns the number of database rows that were changed 1881** or inserted or deleted by the most recently completed SQL statement 1882** on the [database connection] specified by the first parameter. 1883** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1884** or [DELETE] statement are counted. Auxiliary changes caused by 1885** triggers or [foreign key actions] are not counted.)^ Use the 1886** [sqlite3_total_changes()] function to find the total number of changes 1887** including changes caused by triggers and foreign key actions. 1888** 1889** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1890** are not counted. Only real table changes are counted. 1891** 1892** ^(A "row change" is a change to a single row of a single table 1893** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1894** are changed as side effects of [REPLACE] constraint resolution, 1895** rollback, ABORT processing, [DROP TABLE], or by any other 1896** mechanisms do not count as direct row changes.)^ 1897** 1898** A "trigger context" is a scope of execution that begins and 1899** ends with the script of a [CREATE TRIGGER | trigger]. 1900** Most SQL statements are 1901** evaluated outside of any trigger. This is the "top level" 1902** trigger context. If a trigger fires from the top level, a 1903** new trigger context is entered for the duration of that one 1904** trigger. Subtriggers create subcontexts for their duration. 1905** 1906** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1907** not create a new trigger context. 1908** 1909** ^This function returns the number of direct row changes in the 1910** most recent INSERT, UPDATE, or DELETE statement within the same 1911** trigger context. 1912** 1913** ^Thus, when called from the top level, this function returns the 1914** number of changes in the most recent INSERT, UPDATE, or DELETE 1915** that also occurred at the top level. ^(Within the body of a trigger, 1916** the sqlite3_changes() interface can be called to find the number of 1917** changes in the most recently completed INSERT, UPDATE, or DELETE 1918** statement within the body of the same trigger. 1919** However, the number returned does not include changes 1920** caused by subtriggers since those have their own context.)^ 1921** 1922** See also the [sqlite3_total_changes()] interface, the 1923** [count_changes pragma], and the [changes() SQL function]. 1924** 1925** If a separate thread makes changes on the same database connection 1926** while [sqlite3_changes()] is running then the value returned 1927** is unpredictable and not meaningful. 1928*/ 1929int sqlite3_changes(sqlite3*); 1930 1931/* 1932** CAPI3REF: Total Number Of Rows Modified 1933** 1934** ^This function returns the number of row changes caused by [INSERT], 1935** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1936** ^(The count returned by sqlite3_total_changes() includes all changes 1937** from all [CREATE TRIGGER | trigger] contexts and changes made by 1938** [foreign key actions]. However, 1939** the count does not include changes used to implement [REPLACE] constraints, 1940** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1941** count does not include rows of views that fire an [INSTEAD OF trigger], 1942** though if the INSTEAD OF trigger makes changes of its own, those changes 1943** are counted.)^ 1944** ^The sqlite3_total_changes() function counts the changes as soon as 1945** the statement that makes them is completed (when the statement handle 1946** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1947** 1948** See also the [sqlite3_changes()] interface, the 1949** [count_changes pragma], and the [total_changes() SQL function]. 1950** 1951** If a separate thread makes changes on the same database connection 1952** while [sqlite3_total_changes()] is running then the value 1953** returned is unpredictable and not meaningful. 1954*/ 1955int sqlite3_total_changes(sqlite3*); 1956 1957/* 1958** CAPI3REF: Interrupt A Long-Running Query 1959** 1960** ^This function causes any pending database operation to abort and 1961** return at its earliest opportunity. This routine is typically 1962** called in response to a user action such as pressing "Cancel" 1963** or Ctrl-C where the user wants a long query operation to halt 1964** immediately. 1965** 1966** ^It is safe to call this routine from a thread different from the 1967** thread that is currently running the database operation. But it 1968** is not safe to call this routine with a [database connection] that 1969** is closed or might close before sqlite3_interrupt() returns. 1970** 1971** ^If an SQL operation is very nearly finished at the time when 1972** sqlite3_interrupt() is called, then it might not have an opportunity 1973** to be interrupted and might continue to completion. 1974** 1975** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1976** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1977** that is inside an explicit transaction, then the entire transaction 1978** will be rolled back automatically. 1979** 1980** ^The sqlite3_interrupt(D) call is in effect until all currently running 1981** SQL statements on [database connection] D complete. ^Any new SQL statements 1982** that are started after the sqlite3_interrupt() call and before the 1983** running statements reaches zero are interrupted as if they had been 1984** running prior to the sqlite3_interrupt() call. ^New SQL statements 1985** that are started after the running statement count reaches zero are 1986** not effected by the sqlite3_interrupt(). 1987** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1988** SQL statements is a no-op and has no effect on SQL statements 1989** that are started after the sqlite3_interrupt() call returns. 1990** 1991** If the database connection closes while [sqlite3_interrupt()] 1992** is running then bad things will likely happen. 1993*/ 1994void sqlite3_interrupt(sqlite3*); 1995 1996/* 1997** CAPI3REF: Determine If An SQL Statement Is Complete 1998** 1999** These routines are useful during command-line input to determine if the 2000** currently entered text seems to form a complete SQL statement or 2001** if additional input is needed before sending the text into 2002** SQLite for parsing. ^These routines return 1 if the input string 2003** appears to be a complete SQL statement. ^A statement is judged to be 2004** complete if it ends with a semicolon token and is not a prefix of a 2005** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2006** string literals or quoted identifier names or comments are not 2007** independent tokens (they are part of the token in which they are 2008** embedded) and thus do not count as a statement terminator. ^Whitespace 2009** and comments that follow the final semicolon are ignored. 2010** 2011** ^These routines return 0 if the statement is incomplete. ^If a 2012** memory allocation fails, then SQLITE_NOMEM is returned. 2013** 2014** ^These routines do not parse the SQL statements thus 2015** will not detect syntactically incorrect SQL. 2016** 2017** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2018** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2019** automatically by sqlite3_complete16(). If that initialization fails, 2020** then the return value from sqlite3_complete16() will be non-zero 2021** regardless of whether or not the input SQL is complete.)^ 2022** 2023** The input to [sqlite3_complete()] must be a zero-terminated 2024** UTF-8 string. 2025** 2026** The input to [sqlite3_complete16()] must be a zero-terminated 2027** UTF-16 string in native byte order. 2028*/ 2029int sqlite3_complete(const char *sql); 2030int sqlite3_complete16(const void *sql); 2031 2032/* 2033** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2034** 2035** ^This routine sets a callback function that might be invoked whenever 2036** an attempt is made to open a database table that another thread 2037** or process has locked. 2038** 2039** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 2040** is returned immediately upon encountering the lock. ^If the busy callback 2041** is not NULL, then the callback might be invoked with two arguments. 2042** 2043** ^The first argument to the busy handler is a copy of the void* pointer which 2044** is the third argument to sqlite3_busy_handler(). ^The second argument to 2045** the busy handler callback is the number of times that the busy handler has 2046** been invoked for this locking event. ^If the 2047** busy callback returns 0, then no additional attempts are made to 2048** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 2049** ^If the callback returns non-zero, then another attempt 2050** is made to open the database for reading and the cycle repeats. 2051** 2052** The presence of a busy handler does not guarantee that it will be invoked 2053** when there is lock contention. ^If SQLite determines that invoking the busy 2054** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2055** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 2056** Consider a scenario where one process is holding a read lock that 2057** it is trying to promote to a reserved lock and 2058** a second process is holding a reserved lock that it is trying 2059** to promote to an exclusive lock. The first process cannot proceed 2060** because it is blocked by the second and the second process cannot 2061** proceed because it is blocked by the first. If both processes 2062** invoke the busy handlers, neither will make any progress. Therefore, 2063** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2064** will induce the first process to release its read lock and allow 2065** the second process to proceed. 2066** 2067** ^The default busy callback is NULL. 2068** 2069** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 2070** when SQLite is in the middle of a large transaction where all the 2071** changes will not fit into the in-memory cache. SQLite will 2072** already hold a RESERVED lock on the database file, but it needs 2073** to promote this lock to EXCLUSIVE so that it can spill cache 2074** pages into the database file without harm to concurrent 2075** readers. ^If it is unable to promote the lock, then the in-memory 2076** cache will be left in an inconsistent state and so the error 2077** code is promoted from the relatively benign [SQLITE_BUSY] to 2078** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 2079** forces an automatic rollback of the changes. See the 2080** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 2081** CorruptionFollowingBusyError</a> wiki page for a discussion of why 2082** this is important. 2083** 2084** ^(There can only be a single busy handler defined for each 2085** [database connection]. Setting a new busy handler clears any 2086** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2087** will also set or clear the busy handler. 2088** 2089** The busy callback should not take any actions which modify the 2090** database connection that invoked the busy handler. Any such actions 2091** result in undefined behavior. 2092** 2093** A busy handler must not close the database connection 2094** or [prepared statement] that invoked the busy handler. 2095*/ 2096int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2097 2098/* 2099** CAPI3REF: Set A Busy Timeout 2100** 2101** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2102** for a specified amount of time when a table is locked. ^The handler 2103** will sleep multiple times until at least "ms" milliseconds of sleeping 2104** have accumulated. ^After at least "ms" milliseconds of sleeping, 2105** the handler returns 0 which causes [sqlite3_step()] to return 2106** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 2107** 2108** ^Calling this routine with an argument less than or equal to zero 2109** turns off all busy handlers. 2110** 2111** ^(There can only be a single busy handler for a particular 2112** [database connection] any any given moment. If another busy handler 2113** was defined (using [sqlite3_busy_handler()]) prior to calling 2114** this routine, that other busy handler is cleared.)^ 2115*/ 2116int sqlite3_busy_timeout(sqlite3*, int ms); 2117 2118/* 2119** CAPI3REF: Convenience Routines For Running Queries 2120** 2121** This is a legacy interface that is preserved for backwards compatibility. 2122** Use of this interface is not recommended. 2123** 2124** Definition: A <b>result table</b> is memory data structure created by the 2125** [sqlite3_get_table()] interface. A result table records the 2126** complete query results from one or more queries. 2127** 2128** The table conceptually has a number of rows and columns. But 2129** these numbers are not part of the result table itself. These 2130** numbers are obtained separately. Let N be the number of rows 2131** and M be the number of columns. 2132** 2133** A result table is an array of pointers to zero-terminated UTF-8 strings. 2134** There are (N+1)*M elements in the array. The first M pointers point 2135** to zero-terminated strings that contain the names of the columns. 2136** The remaining entries all point to query results. NULL values result 2137** in NULL pointers. All other values are in their UTF-8 zero-terminated 2138** string representation as returned by [sqlite3_column_text()]. 2139** 2140** A result table might consist of one or more memory allocations. 2141** It is not safe to pass a result table directly to [sqlite3_free()]. 2142** A result table should be deallocated using [sqlite3_free_table()]. 2143** 2144** ^(As an example of the result table format, suppose a query result 2145** is as follows: 2146** 2147** <blockquote><pre> 2148** Name | Age 2149** ----------------------- 2150** Alice | 43 2151** Bob | 28 2152** Cindy | 21 2153** </pre></blockquote> 2154** 2155** There are two column (M==2) and three rows (N==3). Thus the 2156** result table has 8 entries. Suppose the result table is stored 2157** in an array names azResult. Then azResult holds this content: 2158** 2159** <blockquote><pre> 2160** azResult[0] = "Name"; 2161** azResult[1] = "Age"; 2162** azResult[2] = "Alice"; 2163** azResult[3] = "43"; 2164** azResult[4] = "Bob"; 2165** azResult[5] = "28"; 2166** azResult[6] = "Cindy"; 2167** azResult[7] = "21"; 2168** </pre></blockquote>)^ 2169** 2170** ^The sqlite3_get_table() function evaluates one or more 2171** semicolon-separated SQL statements in the zero-terminated UTF-8 2172** string of its 2nd parameter and returns a result table to the 2173** pointer given in its 3rd parameter. 2174** 2175** After the application has finished with the result from sqlite3_get_table(), 2176** it must pass the result table pointer to sqlite3_free_table() in order to 2177** release the memory that was malloced. Because of the way the 2178** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2179** function must not try to call [sqlite3_free()] directly. Only 2180** [sqlite3_free_table()] is able to release the memory properly and safely. 2181** 2182** The sqlite3_get_table() interface is implemented as a wrapper around 2183** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2184** to any internal data structures of SQLite. It uses only the public 2185** interface defined here. As a consequence, errors that occur in the 2186** wrapper layer outside of the internal [sqlite3_exec()] call are not 2187** reflected in subsequent calls to [sqlite3_errcode()] or 2188** [sqlite3_errmsg()]. 2189*/ 2190int sqlite3_get_table( 2191 sqlite3 *db, /* An open database */ 2192 const char *zSql, /* SQL to be evaluated */ 2193 char ***pazResult, /* Results of the query */ 2194 int *pnRow, /* Number of result rows written here */ 2195 int *pnColumn, /* Number of result columns written here */ 2196 char **pzErrmsg /* Error msg written here */ 2197); 2198void sqlite3_free_table(char **result); 2199 2200/* 2201** CAPI3REF: Formatted String Printing Functions 2202** 2203** These routines are work-alikes of the "printf()" family of functions 2204** from the standard C library. 2205** 2206** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2207** results into memory obtained from [sqlite3_malloc()]. 2208** The strings returned by these two routines should be 2209** released by [sqlite3_free()]. ^Both routines return a 2210** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2211** memory to hold the resulting string. 2212** 2213** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2214** the standard C library. The result is written into the 2215** buffer supplied as the second parameter whose size is given by 2216** the first parameter. Note that the order of the 2217** first two parameters is reversed from snprintf().)^ This is an 2218** historical accident that cannot be fixed without breaking 2219** backwards compatibility. ^(Note also that sqlite3_snprintf() 2220** returns a pointer to its buffer instead of the number of 2221** characters actually written into the buffer.)^ We admit that 2222** the number of characters written would be a more useful return 2223** value but we cannot change the implementation of sqlite3_snprintf() 2224** now without breaking compatibility. 2225** 2226** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2227** guarantees that the buffer is always zero-terminated. ^The first 2228** parameter "n" is the total size of the buffer, including space for 2229** the zero terminator. So the longest string that can be completely 2230** written will be n-1 characters. 2231** 2232** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2233** 2234** These routines all implement some additional formatting 2235** options that are useful for constructing SQL statements. 2236** All of the usual printf() formatting options apply. In addition, there 2237** is are "%q", "%Q", and "%z" options. 2238** 2239** ^(The %q option works like %s in that it substitutes a nul-terminated 2240** string from the argument list. But %q also doubles every '\'' character. 2241** %q is designed for use inside a string literal.)^ By doubling each '\'' 2242** character it escapes that character and allows it to be inserted into 2243** the string. 2244** 2245** For example, assume the string variable zText contains text as follows: 2246** 2247** <blockquote><pre> 2248** char *zText = "It's a happy day!"; 2249** </pre></blockquote> 2250** 2251** One can use this text in an SQL statement as follows: 2252** 2253** <blockquote><pre> 2254** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2255** sqlite3_exec(db, zSQL, 0, 0, 0); 2256** sqlite3_free(zSQL); 2257** </pre></blockquote> 2258** 2259** Because the %q format string is used, the '\'' character in zText 2260** is escaped and the SQL generated is as follows: 2261** 2262** <blockquote><pre> 2263** INSERT INTO table1 VALUES('It''s a happy day!') 2264** </pre></blockquote> 2265** 2266** This is correct. Had we used %s instead of %q, the generated SQL 2267** would have looked like this: 2268** 2269** <blockquote><pre> 2270** INSERT INTO table1 VALUES('It's a happy day!'); 2271** </pre></blockquote> 2272** 2273** This second example is an SQL syntax error. As a general rule you should 2274** always use %q instead of %s when inserting text into a string literal. 2275** 2276** ^(The %Q option works like %q except it also adds single quotes around 2277** the outside of the total string. Additionally, if the parameter in the 2278** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2279** single quotes).)^ So, for example, one could say: 2280** 2281** <blockquote><pre> 2282** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2283** sqlite3_exec(db, zSQL, 0, 0, 0); 2284** sqlite3_free(zSQL); 2285** </pre></blockquote> 2286** 2287** The code above will render a correct SQL statement in the zSQL 2288** variable even if the zText variable is a NULL pointer. 2289** 2290** ^(The "%z" formatting option works like "%s" but with the 2291** addition that after the string has been read and copied into 2292** the result, [sqlite3_free()] is called on the input string.)^ 2293*/ 2294char *sqlite3_mprintf(const char*,...); 2295char *sqlite3_vmprintf(const char*, va_list); 2296char *sqlite3_snprintf(int,char*,const char*, ...); 2297char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2298 2299/* 2300** CAPI3REF: Memory Allocation Subsystem 2301** 2302** The SQLite core uses these three routines for all of its own 2303** internal memory allocation needs. "Core" in the previous sentence 2304** does not include operating-system specific VFS implementation. The 2305** Windows VFS uses native malloc() and free() for some operations. 2306** 2307** ^The sqlite3_malloc() routine returns a pointer to a block 2308** of memory at least N bytes in length, where N is the parameter. 2309** ^If sqlite3_malloc() is unable to obtain sufficient free 2310** memory, it returns a NULL pointer. ^If the parameter N to 2311** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2312** a NULL pointer. 2313** 2314** ^Calling sqlite3_free() with a pointer previously returned 2315** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2316** that it might be reused. ^The sqlite3_free() routine is 2317** a no-op if is called with a NULL pointer. Passing a NULL pointer 2318** to sqlite3_free() is harmless. After being freed, memory 2319** should neither be read nor written. Even reading previously freed 2320** memory might result in a segmentation fault or other severe error. 2321** Memory corruption, a segmentation fault, or other severe error 2322** might result if sqlite3_free() is called with a non-NULL pointer that 2323** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2324** 2325** ^(The sqlite3_realloc() interface attempts to resize a 2326** prior memory allocation to be at least N bytes, where N is the 2327** second parameter. The memory allocation to be resized is the first 2328** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2329** is a NULL pointer then its behavior is identical to calling 2330** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2331** ^If the second parameter to sqlite3_realloc() is zero or 2332** negative then the behavior is exactly the same as calling 2333** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2334** ^sqlite3_realloc() returns a pointer to a memory allocation 2335** of at least N bytes in size or NULL if sufficient memory is unavailable. 2336** ^If M is the size of the prior allocation, then min(N,M) bytes 2337** of the prior allocation are copied into the beginning of buffer returned 2338** by sqlite3_realloc() and the prior allocation is freed. 2339** ^If sqlite3_realloc() returns NULL, then the prior allocation 2340** is not freed. 2341** 2342** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2343** is always aligned to at least an 8 byte boundary, or to a 2344** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2345** option is used. 2346** 2347** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2348** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2349** implementation of these routines to be omitted. That capability 2350** is no longer provided. Only built-in memory allocators can be used. 2351** 2352** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2353** the system malloc() and free() directly when converting 2354** filenames between the UTF-8 encoding used by SQLite 2355** and whatever filename encoding is used by the particular Windows 2356** installation. Memory allocation errors were detected, but 2357** they were reported back as [SQLITE_CANTOPEN] or 2358** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2359** 2360** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2361** must be either NULL or else pointers obtained from a prior 2362** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2363** not yet been released. 2364** 2365** The application must not read or write any part of 2366** a block of memory after it has been released using 2367** [sqlite3_free()] or [sqlite3_realloc()]. 2368*/ 2369void *sqlite3_malloc(int); 2370void *sqlite3_realloc(void*, int); 2371void sqlite3_free(void*); 2372 2373/* 2374** CAPI3REF: Memory Allocator Statistics 2375** 2376** SQLite provides these two interfaces for reporting on the status 2377** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2378** routines, which form the built-in memory allocation subsystem. 2379** 2380** ^The [sqlite3_memory_used()] routine returns the number of bytes 2381** of memory currently outstanding (malloced but not freed). 2382** ^The [sqlite3_memory_highwater()] routine returns the maximum 2383** value of [sqlite3_memory_used()] since the high-water mark 2384** was last reset. ^The values returned by [sqlite3_memory_used()] and 2385** [sqlite3_memory_highwater()] include any overhead 2386** added by SQLite in its implementation of [sqlite3_malloc()], 2387** but not overhead added by the any underlying system library 2388** routines that [sqlite3_malloc()] may call. 2389** 2390** ^The memory high-water mark is reset to the current value of 2391** [sqlite3_memory_used()] if and only if the parameter to 2392** [sqlite3_memory_highwater()] is true. ^The value returned 2393** by [sqlite3_memory_highwater(1)] is the high-water mark 2394** prior to the reset. 2395*/ 2396sqlite3_int64 sqlite3_memory_used(void); 2397sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2398 2399/* 2400** CAPI3REF: Pseudo-Random Number Generator 2401** 2402** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2403** select random [ROWID | ROWIDs] when inserting new records into a table that 2404** already uses the largest possible [ROWID]. The PRNG is also used for 2405** the build-in random() and randomblob() SQL functions. This interface allows 2406** applications to access the same PRNG for other purposes. 2407** 2408** ^A call to this routine stores N bytes of randomness into buffer P. 2409** ^If N is less than one, then P can be a NULL pointer. 2410** 2411** ^If this routine has not been previously called or if the previous 2412** call had N less than one, then the PRNG is seeded using randomness 2413** obtained from the xRandomness method of the default [sqlite3_vfs] object. 2414** ^If the previous call to this routine had an N of 1 or more then 2415** the pseudo-randomness is generated 2416** internally and without recourse to the [sqlite3_vfs] xRandomness 2417** method. 2418*/ 2419void sqlite3_randomness(int N, void *P); 2420 2421/* 2422** CAPI3REF: Compile-Time Authorization Callbacks 2423** 2424** ^This routine registers an authorizer callback with a particular 2425** [database connection], supplied in the first argument. 2426** ^The authorizer callback is invoked as SQL statements are being compiled 2427** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2428** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2429** points during the compilation process, as logic is being created 2430** to perform various actions, the authorizer callback is invoked to 2431** see if those actions are allowed. ^The authorizer callback should 2432** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2433** specific action but allow the SQL statement to continue to be 2434** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2435** rejected with an error. ^If the authorizer callback returns 2436** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2437** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2438** the authorizer will fail with an error message. 2439** 2440** When the callback returns [SQLITE_OK], that means the operation 2441** requested is ok. ^When the callback returns [SQLITE_DENY], the 2442** [sqlite3_prepare_v2()] or equivalent call that triggered the 2443** authorizer will fail with an error message explaining that 2444** access is denied. 2445** 2446** ^The first parameter to the authorizer callback is a copy of the third 2447** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2448** to the callback is an integer [SQLITE_COPY | action code] that specifies 2449** the particular action to be authorized. ^The third through sixth parameters 2450** to the callback are zero-terminated strings that contain additional 2451** details about the action to be authorized. 2452** 2453** ^If the action code is [SQLITE_READ] 2454** and the callback returns [SQLITE_IGNORE] then the 2455** [prepared statement] statement is constructed to substitute 2456** a NULL value in place of the table column that would have 2457** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2458** return can be used to deny an untrusted user access to individual 2459** columns of a table. 2460** ^If the action code is [SQLITE_DELETE] and the callback returns 2461** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2462** [truncate optimization] is disabled and all rows are deleted individually. 2463** 2464** An authorizer is used when [sqlite3_prepare | preparing] 2465** SQL statements from an untrusted source, to ensure that the SQL statements 2466** do not try to access data they are not allowed to see, or that they do not 2467** try to execute malicious statements that damage the database. For 2468** example, an application may allow a user to enter arbitrary 2469** SQL queries for evaluation by a database. But the application does 2470** not want the user to be able to make arbitrary changes to the 2471** database. An authorizer could then be put in place while the 2472** user-entered SQL is being [sqlite3_prepare | prepared] that 2473** disallows everything except [SELECT] statements. 2474** 2475** Applications that need to process SQL from untrusted sources 2476** might also consider lowering resource limits using [sqlite3_limit()] 2477** and limiting database size using the [max_page_count] [PRAGMA] 2478** in addition to using an authorizer. 2479** 2480** ^(Only a single authorizer can be in place on a database connection 2481** at a time. Each call to sqlite3_set_authorizer overrides the 2482** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2483** The authorizer is disabled by default. 2484** 2485** The authorizer callback must not do anything that will modify 2486** the database connection that invoked the authorizer callback. 2487** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2488** database connections for the meaning of "modify" in this paragraph. 2489** 2490** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2491** statement might be re-prepared during [sqlite3_step()] due to a 2492** schema change. Hence, the application should ensure that the 2493** correct authorizer callback remains in place during the [sqlite3_step()]. 2494** 2495** ^Note that the authorizer callback is invoked only during 2496** [sqlite3_prepare()] or its variants. Authorization is not 2497** performed during statement evaluation in [sqlite3_step()], unless 2498** as stated in the previous paragraph, sqlite3_step() invokes 2499** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2500*/ 2501int sqlite3_set_authorizer( 2502 sqlite3*, 2503 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2504 void *pUserData 2505); 2506 2507/* 2508** CAPI3REF: Authorizer Return Codes 2509** 2510** The [sqlite3_set_authorizer | authorizer callback function] must 2511** return either [SQLITE_OK] or one of these two constants in order 2512** to signal SQLite whether or not the action is permitted. See the 2513** [sqlite3_set_authorizer | authorizer documentation] for additional 2514** information. 2515** 2516** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2517** from the [sqlite3_vtab_on_conflict()] interface. 2518*/ 2519#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2520#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2521 2522/* 2523** CAPI3REF: Authorizer Action Codes 2524** 2525** The [sqlite3_set_authorizer()] interface registers a callback function 2526** that is invoked to authorize certain SQL statement actions. The 2527** second parameter to the callback is an integer code that specifies 2528** what action is being authorized. These are the integer action codes that 2529** the authorizer callback may be passed. 2530** 2531** These action code values signify what kind of operation is to be 2532** authorized. The 3rd and 4th parameters to the authorization 2533** callback function will be parameters or NULL depending on which of these 2534** codes is used as the second parameter. ^(The 5th parameter to the 2535** authorizer callback is the name of the database ("main", "temp", 2536** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2537** is the name of the inner-most trigger or view that is responsible for 2538** the access attempt or NULL if this access attempt is directly from 2539** top-level SQL code. 2540*/ 2541/******************************************* 3rd ************ 4th ***********/ 2542#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2543#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2544#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2545#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2546#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2547#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2548#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2549#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2550#define SQLITE_DELETE 9 /* Table Name NULL */ 2551#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2552#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2553#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2554#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2555#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2556#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2557#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2558#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2559#define SQLITE_INSERT 18 /* Table Name NULL */ 2560#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2561#define SQLITE_READ 20 /* Table Name Column Name */ 2562#define SQLITE_SELECT 21 /* NULL NULL */ 2563#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2564#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2565#define SQLITE_ATTACH 24 /* Filename NULL */ 2566#define SQLITE_DETACH 25 /* Database Name NULL */ 2567#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2568#define SQLITE_REINDEX 27 /* Index Name NULL */ 2569#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2570#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2571#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2572#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2573#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2574#define SQLITE_COPY 0 /* No longer used */ 2575#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2576 2577/* 2578** CAPI3REF: Tracing And Profiling Functions 2579** 2580** These routines register callback functions that can be used for 2581** tracing and profiling the execution of SQL statements. 2582** 2583** ^The callback function registered by sqlite3_trace() is invoked at 2584** various times when an SQL statement is being run by [sqlite3_step()]. 2585** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2586** SQL statement text as the statement first begins executing. 2587** ^(Additional sqlite3_trace() callbacks might occur 2588** as each triggered subprogram is entered. The callbacks for triggers 2589** contain a UTF-8 SQL comment that identifies the trigger.)^ 2590** 2591** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2592** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2593** 2594** ^The callback function registered by sqlite3_profile() is invoked 2595** as each SQL statement finishes. ^The profile callback contains 2596** the original statement text and an estimate of wall-clock time 2597** of how long that statement took to run. ^The profile callback 2598** time is in units of nanoseconds, however the current implementation 2599** is only capable of millisecond resolution so the six least significant 2600** digits in the time are meaningless. Future versions of SQLite 2601** might provide greater resolution on the profiler callback. The 2602** sqlite3_profile() function is considered experimental and is 2603** subject to change in future versions of SQLite. 2604*/ 2605void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2606SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2607 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2608 2609/* 2610** CAPI3REF: Query Progress Callbacks 2611** 2612** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2613** function X to be invoked periodically during long running calls to 2614** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2615** database connection D. An example use for this 2616** interface is to keep a GUI updated during a large query. 2617** 2618** ^The parameter P is passed through as the only parameter to the 2619** callback function X. ^The parameter N is the approximate number of 2620** [virtual machine instructions] that are evaluated between successive 2621** invocations of the callback X. ^If N is less than one then the progress 2622** handler is disabled. 2623** 2624** ^Only a single progress handler may be defined at one time per 2625** [database connection]; setting a new progress handler cancels the 2626** old one. ^Setting parameter X to NULL disables the progress handler. 2627** ^The progress handler is also disabled by setting N to a value less 2628** than 1. 2629** 2630** ^If the progress callback returns non-zero, the operation is 2631** interrupted. This feature can be used to implement a 2632** "Cancel" button on a GUI progress dialog box. 2633** 2634** The progress handler callback must not do anything that will modify 2635** the database connection that invoked the progress handler. 2636** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2637** database connections for the meaning of "modify" in this paragraph. 2638** 2639*/ 2640void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2641 2642/* 2643** CAPI3REF: Opening A New Database Connection 2644** 2645** ^These routines open an SQLite database file as specified by the 2646** filename argument. ^The filename argument is interpreted as UTF-8 for 2647** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2648** order for sqlite3_open16(). ^(A [database connection] handle is usually 2649** returned in *ppDb, even if an error occurs. The only exception is that 2650** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2651** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2652** object.)^ ^(If the database is opened (and/or created) successfully, then 2653** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2654** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2655** an English language description of the error following a failure of any 2656** of the sqlite3_open() routines. 2657** 2658** ^The default encoding for the database will be UTF-8 if 2659** sqlite3_open() or sqlite3_open_v2() is called and 2660** UTF-16 in the native byte order if sqlite3_open16() is used. 2661** 2662** Whether or not an error occurs when it is opened, resources 2663** associated with the [database connection] handle should be released by 2664** passing it to [sqlite3_close()] when it is no longer required. 2665** 2666** The sqlite3_open_v2() interface works like sqlite3_open() 2667** except that it accepts two additional parameters for additional control 2668** over the new database connection. ^(The flags parameter to 2669** sqlite3_open_v2() can take one of 2670** the following three values, optionally combined with the 2671** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2672** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2673** 2674** <dl> 2675** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2676** <dd>The database is opened in read-only mode. If the database does not 2677** already exist, an error is returned.</dd>)^ 2678** 2679** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2680** <dd>The database is opened for reading and writing if possible, or reading 2681** only if the file is write protected by the operating system. In either 2682** case the database must already exist, otherwise an error is returned.</dd>)^ 2683** 2684** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2685** <dd>The database is opened for reading and writing, and is created if 2686** it does not already exist. This is the behavior that is always used for 2687** sqlite3_open() and sqlite3_open16().</dd>)^ 2688** </dl> 2689** 2690** If the 3rd parameter to sqlite3_open_v2() is not one of the 2691** combinations shown above optionally combined with other 2692** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2693** then the behavior is undefined. 2694** 2695** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2696** opens in the multi-thread [threading mode] as long as the single-thread 2697** mode has not been set at compile-time or start-time. ^If the 2698** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2699** in the serialized [threading mode] unless single-thread was 2700** previously selected at compile-time or start-time. 2701** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2702** eligible to use [shared cache mode], regardless of whether or not shared 2703** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2704** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2705** participate in [shared cache mode] even if it is enabled. 2706** 2707** ^The fourth parameter to sqlite3_open_v2() is the name of the 2708** [sqlite3_vfs] object that defines the operating system interface that 2709** the new database connection should use. ^If the fourth parameter is 2710** a NULL pointer then the default [sqlite3_vfs] object is used. 2711** 2712** ^If the filename is ":memory:", then a private, temporary in-memory database 2713** is created for the connection. ^This in-memory database will vanish when 2714** the database connection is closed. Future versions of SQLite might 2715** make use of additional special filenames that begin with the ":" character. 2716** It is recommended that when a database filename actually does begin with 2717** a ":" character you should prefix the filename with a pathname such as 2718** "./" to avoid ambiguity. 2719** 2720** ^If the filename is an empty string, then a private, temporary 2721** on-disk database will be created. ^This private database will be 2722** automatically deleted as soon as the database connection is closed. 2723** 2724** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2725** 2726** ^If [URI filename] interpretation is enabled, and the filename argument 2727** begins with "file:", then the filename is interpreted as a URI. ^URI 2728** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2729** set in the fourth argument to sqlite3_open_v2(), or if it has 2730** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2731** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2732** As of SQLite version 3.7.7, URI filename interpretation is turned off 2733** by default, but future releases of SQLite might enable URI filename 2734** interpretation by default. See "[URI filenames]" for additional 2735** information. 2736** 2737** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2738** authority, then it must be either an empty string or the string 2739** "localhost". ^If the authority is not an empty string or "localhost", an 2740** error is returned to the caller. ^The fragment component of a URI, if 2741** present, is ignored. 2742** 2743** ^SQLite uses the path component of the URI as the name of the disk file 2744** which contains the database. ^If the path begins with a '/' character, 2745** then it is interpreted as an absolute path. ^If the path does not begin 2746** with a '/' (meaning that the authority section is omitted from the URI) 2747** then the path is interpreted as a relative path. 2748** ^On windows, the first component of an absolute path 2749** is a drive specification (e.g. "C:"). 2750** 2751** [[core URI query parameters]] 2752** The query component of a URI may contain parameters that are interpreted 2753** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2754** SQLite interprets the following three query parameters: 2755** 2756** <ul> 2757** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2758** a VFS object that provides the operating system interface that should 2759** be used to access the database file on disk. ^If this option is set to 2760** an empty string the default VFS object is used. ^Specifying an unknown 2761** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2762** present, then the VFS specified by the option takes precedence over 2763** the value passed as the fourth parameter to sqlite3_open_v2(). 2764** 2765** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2766** "rwc", or "memory". Attempting to set it to any other value is 2767** an error)^. 2768** ^If "ro" is specified, then the database is opened for read-only 2769** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2770** third argument to sqlite3_open_v2(). ^If the mode option is set to 2771** "rw", then the database is opened for read-write (but not create) 2772** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2773** been set. ^Value "rwc" is equivalent to setting both 2774** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2775** set to "memory" then a pure [in-memory database] that never reads 2776** or writes from disk is used. ^It is an error to specify a value for 2777** the mode parameter that is less restrictive than that specified by 2778** the flags passed in the third parameter to sqlite3_open_v2(). 2779** 2780** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2781** "private". ^Setting it to "shared" is equivalent to setting the 2782** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2783** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2784** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2785** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2786** a URI filename, its value overrides any behavior requested by setting 2787** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2788** 2789** <li> <b>psow</b>: ^The psow parameter may be "true" (or "on" or "yes" or 2790** "1") or "false" (or "off" or "no" or "0") to indicate that the 2791** [powersafe overwrite] property does or does not apply to the 2792** storage media on which the database file resides. ^The psow query 2793** parameter only works for the built-in unix and Windows VFSes. 2794** 2795** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 2796** which if set disables file locking in rollback journal modes. This 2797** is useful for accessing a database on a filesystem that does not 2798** support locking. Caution: Database corruption might result if two 2799** or more processes write to the same database and any one of those 2800** processes uses nolock=1. 2801** 2802** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 2803** parameter that indicates that the database file is stored on 2804** read-only media. ^When immutable is set, SQLite assumes that the 2805** database file cannot be changed, even by a process with higher 2806** privilege, and so the database is opened read-only and all locking 2807** and change detection is disabled. Caution: Setting the immutable 2808** property on a database file that does in fact change can result 2809** in incorrect query results and/or [SQLITE_CORRUPT] errors. 2810** See also: [SQLITE_IOCAP_IMMUTABLE]. 2811** 2812** </ul> 2813** 2814** ^Specifying an unknown parameter in the query component of a URI is not an 2815** error. Future versions of SQLite might understand additional query 2816** parameters. See "[query parameters with special meaning to SQLite]" for 2817** additional information. 2818** 2819** [[URI filename examples]] <h3>URI filename examples</h3> 2820** 2821** <table border="1" align=center cellpadding=5> 2822** <tr><th> URI filenames <th> Results 2823** <tr><td> file:data.db <td> 2824** Open the file "data.db" in the current directory. 2825** <tr><td> file:/home/fred/data.db<br> 2826** file:///home/fred/data.db <br> 2827** file://localhost/home/fred/data.db <br> <td> 2828** Open the database file "/home/fred/data.db". 2829** <tr><td> file://darkstar/home/fred/data.db <td> 2830** An error. "darkstar" is not a recognized authority. 2831** <tr><td style="white-space:nowrap"> 2832** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2833** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2834** C:. Note that the %20 escaping in this example is not strictly 2835** necessary - space characters can be used literally 2836** in URI filenames. 2837** <tr><td> file:data.db?mode=ro&cache=private <td> 2838** Open file "data.db" in the current directory for read-only access. 2839** Regardless of whether or not shared-cache mode is enabled by 2840** default, use a private cache. 2841** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 2842** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 2843** that uses dot-files in place of posix advisory locking. 2844** <tr><td> file:data.db?mode=readonly <td> 2845** An error. "readonly" is not a valid option for the "mode" parameter. 2846** </table> 2847** 2848** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2849** query components of a URI. A hexadecimal escape sequence consists of a 2850** percent sign - "%" - followed by exactly two hexadecimal digits 2851** specifying an octet value. ^Before the path or query components of a 2852** URI filename are interpreted, they are encoded using UTF-8 and all 2853** hexadecimal escape sequences replaced by a single byte containing the 2854** corresponding octet. If this process generates an invalid UTF-8 encoding, 2855** the results are undefined. 2856** 2857** <b>Note to Windows users:</b> The encoding used for the filename argument 2858** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2859** codepage is currently defined. Filenames containing international 2860** characters must be converted to UTF-8 prior to passing them into 2861** sqlite3_open() or sqlite3_open_v2(). 2862** 2863** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2864** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2865** features that require the use of temporary files may fail. 2866** 2867** See also: [sqlite3_temp_directory] 2868*/ 2869int sqlite3_open( 2870 const char *filename, /* Database filename (UTF-8) */ 2871 sqlite3 **ppDb /* OUT: SQLite db handle */ 2872); 2873int sqlite3_open16( 2874 const void *filename, /* Database filename (UTF-16) */ 2875 sqlite3 **ppDb /* OUT: SQLite db handle */ 2876); 2877int sqlite3_open_v2( 2878 const char *filename, /* Database filename (UTF-8) */ 2879 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2880 int flags, /* Flags */ 2881 const char *zVfs /* Name of VFS module to use */ 2882); 2883 2884/* 2885** CAPI3REF: Obtain Values For URI Parameters 2886** 2887** These are utility routines, useful to VFS implementations, that check 2888** to see if a database file was a URI that contained a specific query 2889** parameter, and if so obtains the value of that query parameter. 2890** 2891** If F is the database filename pointer passed into the xOpen() method of 2892** a VFS implementation when the flags parameter to xOpen() has one or 2893** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2894** P is the name of the query parameter, then 2895** sqlite3_uri_parameter(F,P) returns the value of the P 2896** parameter if it exists or a NULL pointer if P does not appear as a 2897** query parameter on F. If P is a query parameter of F 2898** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2899** a pointer to an empty string. 2900** 2901** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2902** parameter and returns true (1) or false (0) according to the value 2903** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2904** value of query parameter P is one of "yes", "true", or "on" in any 2905** case or if the value begins with a non-zero number. The 2906** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2907** query parameter P is one of "no", "false", or "off" in any case or 2908** if the value begins with a numeric zero. If P is not a query 2909** parameter on F or if the value of P is does not match any of the 2910** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2911** 2912** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2913** 64-bit signed integer and returns that integer, or D if P does not 2914** exist. If the value of P is something other than an integer, then 2915** zero is returned. 2916** 2917** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2918** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2919** is not a database file pathname pointer that SQLite passed into the xOpen 2920** VFS method, then the behavior of this routine is undefined and probably 2921** undesirable. 2922*/ 2923const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2924int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2925sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2926 2927 2928/* 2929** CAPI3REF: Error Codes And Messages 2930** 2931** ^The sqlite3_errcode() interface returns the numeric [result code] or 2932** [extended result code] for the most recent failed sqlite3_* API call 2933** associated with a [database connection]. If a prior API call failed 2934** but the most recent API call succeeded, the return value from 2935** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2936** interface is the same except that it always returns the 2937** [extended result code] even when extended result codes are 2938** disabled. 2939** 2940** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2941** text that describes the error, as either UTF-8 or UTF-16 respectively. 2942** ^(Memory to hold the error message string is managed internally. 2943** The application does not need to worry about freeing the result. 2944** However, the error string might be overwritten or deallocated by 2945** subsequent calls to other SQLite interface functions.)^ 2946** 2947** ^The sqlite3_errstr() interface returns the English-language text 2948** that describes the [result code], as UTF-8. 2949** ^(Memory to hold the error message string is managed internally 2950** and must not be freed by the application)^. 2951** 2952** When the serialized [threading mode] is in use, it might be the 2953** case that a second error occurs on a separate thread in between 2954** the time of the first error and the call to these interfaces. 2955** When that happens, the second error will be reported since these 2956** interfaces always report the most recent result. To avoid 2957** this, each thread can obtain exclusive use of the [database connection] D 2958** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2959** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2960** all calls to the interfaces listed here are completed. 2961** 2962** If an interface fails with SQLITE_MISUSE, that means the interface 2963** was invoked incorrectly by the application. In that case, the 2964** error code and message may or may not be set. 2965*/ 2966int sqlite3_errcode(sqlite3 *db); 2967int sqlite3_extended_errcode(sqlite3 *db); 2968const char *sqlite3_errmsg(sqlite3*); 2969const void *sqlite3_errmsg16(sqlite3*); 2970const char *sqlite3_errstr(int); 2971 2972/* 2973** CAPI3REF: SQL Statement Object 2974** KEYWORDS: {prepared statement} {prepared statements} 2975** 2976** An instance of this object represents a single SQL statement. 2977** This object is variously known as a "prepared statement" or a 2978** "compiled SQL statement" or simply as a "statement". 2979** 2980** The life of a statement object goes something like this: 2981** 2982** <ol> 2983** <li> Create the object using [sqlite3_prepare_v2()] or a related 2984** function. 2985** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2986** interfaces. 2987** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2988** <li> Reset the statement using [sqlite3_reset()] then go back 2989** to step 2. Do this zero or more times. 2990** <li> Destroy the object using [sqlite3_finalize()]. 2991** </ol> 2992** 2993** Refer to documentation on individual methods above for additional 2994** information. 2995*/ 2996typedef struct sqlite3_stmt sqlite3_stmt; 2997 2998/* 2999** CAPI3REF: Run-time Limits 3000** 3001** ^(This interface allows the size of various constructs to be limited 3002** on a connection by connection basis. The first parameter is the 3003** [database connection] whose limit is to be set or queried. The 3004** second parameter is one of the [limit categories] that define a 3005** class of constructs to be size limited. The third parameter is the 3006** new limit for that construct.)^ 3007** 3008** ^If the new limit is a negative number, the limit is unchanged. 3009** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3010** [limits | hard upper bound] 3011** set at compile-time by a C preprocessor macro called 3012** [limits | SQLITE_MAX_<i>NAME</i>]. 3013** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3014** ^Attempts to increase a limit above its hard upper bound are 3015** silently truncated to the hard upper bound. 3016** 3017** ^Regardless of whether or not the limit was changed, the 3018** [sqlite3_limit()] interface returns the prior value of the limit. 3019** ^Hence, to find the current value of a limit without changing it, 3020** simply invoke this interface with the third parameter set to -1. 3021** 3022** Run-time limits are intended for use in applications that manage 3023** both their own internal database and also databases that are controlled 3024** by untrusted external sources. An example application might be a 3025** web browser that has its own databases for storing history and 3026** separate databases controlled by JavaScript applications downloaded 3027** off the Internet. The internal databases can be given the 3028** large, default limits. Databases managed by external sources can 3029** be given much smaller limits designed to prevent a denial of service 3030** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3031** interface to further control untrusted SQL. The size of the database 3032** created by an untrusted script can be contained using the 3033** [max_page_count] [PRAGMA]. 3034** 3035** New run-time limit categories may be added in future releases. 3036*/ 3037int sqlite3_limit(sqlite3*, int id, int newVal); 3038 3039/* 3040** CAPI3REF: Run-Time Limit Categories 3041** KEYWORDS: {limit category} {*limit categories} 3042** 3043** These constants define various performance limits 3044** that can be lowered at run-time using [sqlite3_limit()]. 3045** The synopsis of the meanings of the various limits is shown below. 3046** Additional information is available at [limits | Limits in SQLite]. 3047** 3048** <dl> 3049** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3050** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3051** 3052** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3053** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3054** 3055** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3056** <dd>The maximum number of columns in a table definition or in the 3057** result set of a [SELECT] or the maximum number of columns in an index 3058** or in an ORDER BY or GROUP BY clause.</dd>)^ 3059** 3060** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3061** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3062** 3063** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3064** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3065** 3066** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3067** <dd>The maximum number of instructions in a virtual machine program 3068** used to implement an SQL statement. This limit is not currently 3069** enforced, though that might be added in some future release of 3070** SQLite.</dd>)^ 3071** 3072** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3073** <dd>The maximum number of arguments on a function.</dd>)^ 3074** 3075** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3076** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3077** 3078** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3079** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3080** <dd>The maximum length of the pattern argument to the [LIKE] or 3081** [GLOB] operators.</dd>)^ 3082** 3083** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3084** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3085** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3086** 3087** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3088** <dd>The maximum depth of recursion for triggers.</dd>)^ 3089** </dl> 3090*/ 3091#define SQLITE_LIMIT_LENGTH 0 3092#define SQLITE_LIMIT_SQL_LENGTH 1 3093#define SQLITE_LIMIT_COLUMN 2 3094#define SQLITE_LIMIT_EXPR_DEPTH 3 3095#define SQLITE_LIMIT_COMPOUND_SELECT 4 3096#define SQLITE_LIMIT_VDBE_OP 5 3097#define SQLITE_LIMIT_FUNCTION_ARG 6 3098#define SQLITE_LIMIT_ATTACHED 7 3099#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3100#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3101#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3102 3103/* 3104** CAPI3REF: Compiling An SQL Statement 3105** KEYWORDS: {SQL statement compiler} 3106** 3107** To execute an SQL query, it must first be compiled into a byte-code 3108** program using one of these routines. 3109** 3110** The first argument, "db", is a [database connection] obtained from a 3111** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3112** [sqlite3_open16()]. The database connection must not have been closed. 3113** 3114** The second argument, "zSql", is the statement to be compiled, encoded 3115** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3116** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3117** use UTF-16. 3118** 3119** ^If the nByte argument is less than zero, then zSql is read up to the 3120** first zero terminator. ^If nByte is non-negative, then it is the maximum 3121** number of bytes read from zSql. ^When nByte is non-negative, the 3122** zSql string ends at either the first '\000' or '\u0000' character or 3123** the nByte-th byte, whichever comes first. If the caller knows 3124** that the supplied string is nul-terminated, then there is a small 3125** performance advantage to be gained by passing an nByte parameter that 3126** is equal to the number of bytes in the input string <i>including</i> 3127** the nul-terminator bytes as this saves SQLite from having to 3128** make a copy of the input string. 3129** 3130** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3131** past the end of the first SQL statement in zSql. These routines only 3132** compile the first statement in zSql, so *pzTail is left pointing to 3133** what remains uncompiled. 3134** 3135** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3136** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3137** to NULL. ^If the input text contains no SQL (if the input is an empty 3138** string or a comment) then *ppStmt is set to NULL. 3139** The calling procedure is responsible for deleting the compiled 3140** SQL statement using [sqlite3_finalize()] after it has finished with it. 3141** ppStmt may not be NULL. 3142** 3143** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3144** otherwise an [error code] is returned. 3145** 3146** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3147** recommended for all new programs. The two older interfaces are retained 3148** for backwards compatibility, but their use is discouraged. 3149** ^In the "v2" interfaces, the prepared statement 3150** that is returned (the [sqlite3_stmt] object) contains a copy of the 3151** original SQL text. This causes the [sqlite3_step()] interface to 3152** behave differently in three ways: 3153** 3154** <ol> 3155** <li> 3156** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3157** always used to do, [sqlite3_step()] will automatically recompile the SQL 3158** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3159** retries will occur before sqlite3_step() gives up and returns an error. 3160** </li> 3161** 3162** <li> 3163** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3164** [error codes] or [extended error codes]. ^The legacy behavior was that 3165** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3166** and the application would have to make a second call to [sqlite3_reset()] 3167** in order to find the underlying cause of the problem. With the "v2" prepare 3168** interfaces, the underlying reason for the error is returned immediately. 3169** </li> 3170** 3171** <li> 3172** ^If the specific value bound to [parameter | host parameter] in the 3173** WHERE clause might influence the choice of query plan for a statement, 3174** then the statement will be automatically recompiled, as if there had been 3175** a schema change, on the first [sqlite3_step()] call following any change 3176** to the [sqlite3_bind_text | bindings] of that [parameter]. 3177** ^The specific value of WHERE-clause [parameter] might influence the 3178** choice of query plan if the parameter is the left-hand side of a [LIKE] 3179** or [GLOB] operator or if the parameter is compared to an indexed column 3180** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3181** </li> 3182** </ol> 3183*/ 3184int sqlite3_prepare( 3185 sqlite3 *db, /* Database handle */ 3186 const char *zSql, /* SQL statement, UTF-8 encoded */ 3187 int nByte, /* Maximum length of zSql in bytes. */ 3188 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3189 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3190); 3191int sqlite3_prepare_v2( 3192 sqlite3 *db, /* Database handle */ 3193 const char *zSql, /* SQL statement, UTF-8 encoded */ 3194 int nByte, /* Maximum length of zSql in bytes. */ 3195 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3196 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3197); 3198int sqlite3_prepare16( 3199 sqlite3 *db, /* Database handle */ 3200 const void *zSql, /* SQL statement, UTF-16 encoded */ 3201 int nByte, /* Maximum length of zSql in bytes. */ 3202 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3203 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3204); 3205int sqlite3_prepare16_v2( 3206 sqlite3 *db, /* Database handle */ 3207 const void *zSql, /* SQL statement, UTF-16 encoded */ 3208 int nByte, /* Maximum length of zSql in bytes. */ 3209 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3210 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3211); 3212 3213/* 3214** CAPI3REF: Retrieving Statement SQL 3215** 3216** ^This interface can be used to retrieve a saved copy of the original 3217** SQL text used to create a [prepared statement] if that statement was 3218** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3219*/ 3220const char *sqlite3_sql(sqlite3_stmt *pStmt); 3221 3222/* 3223** CAPI3REF: Determine If An SQL Statement Writes The Database 3224** 3225** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3226** and only if the [prepared statement] X makes no direct changes to 3227** the content of the database file. 3228** 3229** Note that [application-defined SQL functions] or 3230** [virtual tables] might change the database indirectly as a side effect. 3231** ^(For example, if an application defines a function "eval()" that 3232** calls [sqlite3_exec()], then the following SQL statement would 3233** change the database file through side-effects: 3234** 3235** <blockquote><pre> 3236** SELECT eval('DELETE FROM t1') FROM t2; 3237** </pre></blockquote> 3238** 3239** But because the [SELECT] statement does not change the database file 3240** directly, sqlite3_stmt_readonly() would still return true.)^ 3241** 3242** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3243** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3244** since the statements themselves do not actually modify the database but 3245** rather they control the timing of when other statements modify the 3246** database. ^The [ATTACH] and [DETACH] statements also cause 3247** sqlite3_stmt_readonly() to return true since, while those statements 3248** change the configuration of a database connection, they do not make 3249** changes to the content of the database files on disk. 3250*/ 3251int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3252 3253/* 3254** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3255** 3256** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3257** [prepared statement] S has been stepped at least once using 3258** [sqlite3_step(S)] but has not run to completion and/or has not 3259** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3260** interface returns false if S is a NULL pointer. If S is not a 3261** NULL pointer and is not a pointer to a valid [prepared statement] 3262** object, then the behavior is undefined and probably undesirable. 3263** 3264** This interface can be used in combination [sqlite3_next_stmt()] 3265** to locate all prepared statements associated with a database 3266** connection that are in need of being reset. This can be used, 3267** for example, in diagnostic routines to search for prepared 3268** statements that are holding a transaction open. 3269*/ 3270int sqlite3_stmt_busy(sqlite3_stmt*); 3271 3272/* 3273** CAPI3REF: Dynamically Typed Value Object 3274** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3275** 3276** SQLite uses the sqlite3_value object to represent all values 3277** that can be stored in a database table. SQLite uses dynamic typing 3278** for the values it stores. ^Values stored in sqlite3_value objects 3279** can be integers, floating point values, strings, BLOBs, or NULL. 3280** 3281** An sqlite3_value object may be either "protected" or "unprotected". 3282** Some interfaces require a protected sqlite3_value. Other interfaces 3283** will accept either a protected or an unprotected sqlite3_value. 3284** Every interface that accepts sqlite3_value arguments specifies 3285** whether or not it requires a protected sqlite3_value. 3286** 3287** The terms "protected" and "unprotected" refer to whether or not 3288** a mutex is held. An internal mutex is held for a protected 3289** sqlite3_value object but no mutex is held for an unprotected 3290** sqlite3_value object. If SQLite is compiled to be single-threaded 3291** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3292** or if SQLite is run in one of reduced mutex modes 3293** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3294** then there is no distinction between protected and unprotected 3295** sqlite3_value objects and they can be used interchangeably. However, 3296** for maximum code portability it is recommended that applications 3297** still make the distinction between protected and unprotected 3298** sqlite3_value objects even when not strictly required. 3299** 3300** ^The sqlite3_value objects that are passed as parameters into the 3301** implementation of [application-defined SQL functions] are protected. 3302** ^The sqlite3_value object returned by 3303** [sqlite3_column_value()] is unprotected. 3304** Unprotected sqlite3_value objects may only be used with 3305** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3306** The [sqlite3_value_blob | sqlite3_value_type()] family of 3307** interfaces require protected sqlite3_value objects. 3308*/ 3309typedef struct Mem sqlite3_value; 3310 3311/* 3312** CAPI3REF: SQL Function Context Object 3313** 3314** The context in which an SQL function executes is stored in an 3315** sqlite3_context object. ^A pointer to an sqlite3_context object 3316** is always first parameter to [application-defined SQL functions]. 3317** The application-defined SQL function implementation will pass this 3318** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3319** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3320** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3321** and/or [sqlite3_set_auxdata()]. 3322*/ 3323typedef struct sqlite3_context sqlite3_context; 3324 3325/* 3326** CAPI3REF: Binding Values To Prepared Statements 3327** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3328** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3329** 3330** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3331** literals may be replaced by a [parameter] that matches one of following 3332** templates: 3333** 3334** <ul> 3335** <li> ? 3336** <li> ?NNN 3337** <li> :VVV 3338** <li> @VVV 3339** <li> $VVV 3340** </ul> 3341** 3342** In the templates above, NNN represents an integer literal, 3343** and VVV represents an alphanumeric identifier.)^ ^The values of these 3344** parameters (also called "host parameter names" or "SQL parameters") 3345** can be set using the sqlite3_bind_*() routines defined here. 3346** 3347** ^The first argument to the sqlite3_bind_*() routines is always 3348** a pointer to the [sqlite3_stmt] object returned from 3349** [sqlite3_prepare_v2()] or its variants. 3350** 3351** ^The second argument is the index of the SQL parameter to be set. 3352** ^The leftmost SQL parameter has an index of 1. ^When the same named 3353** SQL parameter is used more than once, second and subsequent 3354** occurrences have the same index as the first occurrence. 3355** ^The index for named parameters can be looked up using the 3356** [sqlite3_bind_parameter_index()] API if desired. ^The index 3357** for "?NNN" parameters is the value of NNN. 3358** ^The NNN value must be between 1 and the [sqlite3_limit()] 3359** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3360** 3361** ^The third argument is the value to bind to the parameter. 3362** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3363** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3364** is ignored and the end result is the same as sqlite3_bind_null(). 3365** 3366** ^(In those routines that have a fourth argument, its value is the 3367** number of bytes in the parameter. To be clear: the value is the 3368** number of <u>bytes</u> in the value, not the number of characters.)^ 3369** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3370** is negative, then the length of the string is 3371** the number of bytes up to the first zero terminator. 3372** If the fourth parameter to sqlite3_bind_blob() is negative, then 3373** the behavior is undefined. 3374** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3375** or sqlite3_bind_text16() then that parameter must be the byte offset 3376** where the NUL terminator would occur assuming the string were NUL 3377** terminated. If any NUL characters occur at byte offsets less than 3378** the value of the fourth parameter then the resulting string value will 3379** contain embedded NULs. The result of expressions involving strings 3380** with embedded NULs is undefined. 3381** 3382** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3383** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3384** string after SQLite has finished with it. ^The destructor is called 3385** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3386** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3387** ^If the fifth argument is 3388** the special value [SQLITE_STATIC], then SQLite assumes that the 3389** information is in static, unmanaged space and does not need to be freed. 3390** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3391** SQLite makes its own private copy of the data immediately, before 3392** the sqlite3_bind_*() routine returns. 3393** 3394** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3395** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3396** (just an integer to hold its size) while it is being processed. 3397** Zeroblobs are intended to serve as placeholders for BLOBs whose 3398** content is later written using 3399** [sqlite3_blob_open | incremental BLOB I/O] routines. 3400** ^A negative value for the zeroblob results in a zero-length BLOB. 3401** 3402** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3403** for the [prepared statement] or with a prepared statement for which 3404** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3405** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3406** routine is passed a [prepared statement] that has been finalized, the 3407** result is undefined and probably harmful. 3408** 3409** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3410** ^Unbound parameters are interpreted as NULL. 3411** 3412** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3413** [error code] if anything goes wrong. 3414** ^[SQLITE_RANGE] is returned if the parameter 3415** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3416** 3417** See also: [sqlite3_bind_parameter_count()], 3418** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3419*/ 3420int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3421int sqlite3_bind_double(sqlite3_stmt*, int, double); 3422int sqlite3_bind_int(sqlite3_stmt*, int, int); 3423int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3424int sqlite3_bind_null(sqlite3_stmt*, int); 3425int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3426int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3427int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3428int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3429 3430/* 3431** CAPI3REF: Number Of SQL Parameters 3432** 3433** ^This routine can be used to find the number of [SQL parameters] 3434** in a [prepared statement]. SQL parameters are tokens of the 3435** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3436** placeholders for values that are [sqlite3_bind_blob | bound] 3437** to the parameters at a later time. 3438** 3439** ^(This routine actually returns the index of the largest (rightmost) 3440** parameter. For all forms except ?NNN, this will correspond to the 3441** number of unique parameters. If parameters of the ?NNN form are used, 3442** there may be gaps in the list.)^ 3443** 3444** See also: [sqlite3_bind_blob|sqlite3_bind()], 3445** [sqlite3_bind_parameter_name()], and 3446** [sqlite3_bind_parameter_index()]. 3447*/ 3448int sqlite3_bind_parameter_count(sqlite3_stmt*); 3449 3450/* 3451** CAPI3REF: Name Of A Host Parameter 3452** 3453** ^The sqlite3_bind_parameter_name(P,N) interface returns 3454** the name of the N-th [SQL parameter] in the [prepared statement] P. 3455** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3456** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3457** respectively. 3458** In other words, the initial ":" or "$" or "@" or "?" 3459** is included as part of the name.)^ 3460** ^Parameters of the form "?" without a following integer have no name 3461** and are referred to as "nameless" or "anonymous parameters". 3462** 3463** ^The first host parameter has an index of 1, not 0. 3464** 3465** ^If the value N is out of range or if the N-th parameter is 3466** nameless, then NULL is returned. ^The returned string is 3467** always in UTF-8 encoding even if the named parameter was 3468** originally specified as UTF-16 in [sqlite3_prepare16()] or 3469** [sqlite3_prepare16_v2()]. 3470** 3471** See also: [sqlite3_bind_blob|sqlite3_bind()], 3472** [sqlite3_bind_parameter_count()], and 3473** [sqlite3_bind_parameter_index()]. 3474*/ 3475const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3476 3477/* 3478** CAPI3REF: Index Of A Parameter With A Given Name 3479** 3480** ^Return the index of an SQL parameter given its name. ^The 3481** index value returned is suitable for use as the second 3482** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3483** is returned if no matching parameter is found. ^The parameter 3484** name must be given in UTF-8 even if the original statement 3485** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3486** 3487** See also: [sqlite3_bind_blob|sqlite3_bind()], 3488** [sqlite3_bind_parameter_count()], and 3489** [sqlite3_bind_parameter_index()]. 3490*/ 3491int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3492 3493/* 3494** CAPI3REF: Reset All Bindings On A Prepared Statement 3495** 3496** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3497** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3498** ^Use this routine to reset all host parameters to NULL. 3499*/ 3500int sqlite3_clear_bindings(sqlite3_stmt*); 3501 3502/* 3503** CAPI3REF: Number Of Columns In A Result Set 3504** 3505** ^Return the number of columns in the result set returned by the 3506** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3507** statement that does not return data (for example an [UPDATE]). 3508** 3509** See also: [sqlite3_data_count()] 3510*/ 3511int sqlite3_column_count(sqlite3_stmt *pStmt); 3512 3513/* 3514** CAPI3REF: Column Names In A Result Set 3515** 3516** ^These routines return the name assigned to a particular column 3517** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3518** interface returns a pointer to a zero-terminated UTF-8 string 3519** and sqlite3_column_name16() returns a pointer to a zero-terminated 3520** UTF-16 string. ^The first parameter is the [prepared statement] 3521** that implements the [SELECT] statement. ^The second parameter is the 3522** column number. ^The leftmost column is number 0. 3523** 3524** ^The returned string pointer is valid until either the [prepared statement] 3525** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3526** reprepared by the first call to [sqlite3_step()] for a particular run 3527** or until the next call to 3528** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3529** 3530** ^If sqlite3_malloc() fails during the processing of either routine 3531** (for example during a conversion from UTF-8 to UTF-16) then a 3532** NULL pointer is returned. 3533** 3534** ^The name of a result column is the value of the "AS" clause for 3535** that column, if there is an AS clause. If there is no AS clause 3536** then the name of the column is unspecified and may change from 3537** one release of SQLite to the next. 3538*/ 3539const char *sqlite3_column_name(sqlite3_stmt*, int N); 3540const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3541 3542/* 3543** CAPI3REF: Source Of Data In A Query Result 3544** 3545** ^These routines provide a means to determine the database, table, and 3546** table column that is the origin of a particular result column in 3547** [SELECT] statement. 3548** ^The name of the database or table or column can be returned as 3549** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3550** the database name, the _table_ routines return the table name, and 3551** the origin_ routines return the column name. 3552** ^The returned string is valid until the [prepared statement] is destroyed 3553** using [sqlite3_finalize()] or until the statement is automatically 3554** reprepared by the first call to [sqlite3_step()] for a particular run 3555** or until the same information is requested 3556** again in a different encoding. 3557** 3558** ^The names returned are the original un-aliased names of the 3559** database, table, and column. 3560** 3561** ^The first argument to these interfaces is a [prepared statement]. 3562** ^These functions return information about the Nth result column returned by 3563** the statement, where N is the second function argument. 3564** ^The left-most column is column 0 for these routines. 3565** 3566** ^If the Nth column returned by the statement is an expression or 3567** subquery and is not a column value, then all of these functions return 3568** NULL. ^These routine might also return NULL if a memory allocation error 3569** occurs. ^Otherwise, they return the name of the attached database, table, 3570** or column that query result column was extracted from. 3571** 3572** ^As with all other SQLite APIs, those whose names end with "16" return 3573** UTF-16 encoded strings and the other functions return UTF-8. 3574** 3575** ^These APIs are only available if the library was compiled with the 3576** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3577** 3578** If two or more threads call one or more of these routines against the same 3579** prepared statement and column at the same time then the results are 3580** undefined. 3581** 3582** If two or more threads call one or more 3583** [sqlite3_column_database_name | column metadata interfaces] 3584** for the same [prepared statement] and result column 3585** at the same time then the results are undefined. 3586*/ 3587const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3588const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3589const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3590const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3591const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3592const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3593 3594/* 3595** CAPI3REF: Declared Datatype Of A Query Result 3596** 3597** ^(The first parameter is a [prepared statement]. 3598** If this statement is a [SELECT] statement and the Nth column of the 3599** returned result set of that [SELECT] is a table column (not an 3600** expression or subquery) then the declared type of the table 3601** column is returned.)^ ^If the Nth column of the result set is an 3602** expression or subquery, then a NULL pointer is returned. 3603** ^The returned string is always UTF-8 encoded. 3604** 3605** ^(For example, given the database schema: 3606** 3607** CREATE TABLE t1(c1 VARIANT); 3608** 3609** and the following statement to be compiled: 3610** 3611** SELECT c1 + 1, c1 FROM t1; 3612** 3613** this routine would return the string "VARIANT" for the second result 3614** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3615** 3616** ^SQLite uses dynamic run-time typing. ^So just because a column 3617** is declared to contain a particular type does not mean that the 3618** data stored in that column is of the declared type. SQLite is 3619** strongly typed, but the typing is dynamic not static. ^Type 3620** is associated with individual values, not with the containers 3621** used to hold those values. 3622*/ 3623const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3624const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3625 3626/* 3627** CAPI3REF: Evaluate An SQL Statement 3628** 3629** After a [prepared statement] has been prepared using either 3630** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3631** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3632** must be called one or more times to evaluate the statement. 3633** 3634** The details of the behavior of the sqlite3_step() interface depend 3635** on whether the statement was prepared using the newer "v2" interface 3636** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3637** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3638** new "v2" interface is recommended for new applications but the legacy 3639** interface will continue to be supported. 3640** 3641** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3642** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3643** ^With the "v2" interface, any of the other [result codes] or 3644** [extended result codes] might be returned as well. 3645** 3646** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3647** database locks it needs to do its job. ^If the statement is a [COMMIT] 3648** or occurs outside of an explicit transaction, then you can retry the 3649** statement. If the statement is not a [COMMIT] and occurs within an 3650** explicit transaction then you should rollback the transaction before 3651** continuing. 3652** 3653** ^[SQLITE_DONE] means that the statement has finished executing 3654** successfully. sqlite3_step() should not be called again on this virtual 3655** machine without first calling [sqlite3_reset()] to reset the virtual 3656** machine back to its initial state. 3657** 3658** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3659** is returned each time a new row of data is ready for processing by the 3660** caller. The values may be accessed using the [column access functions]. 3661** sqlite3_step() is called again to retrieve the next row of data. 3662** 3663** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3664** violation) has occurred. sqlite3_step() should not be called again on 3665** the VM. More information may be found by calling [sqlite3_errmsg()]. 3666** ^With the legacy interface, a more specific error code (for example, 3667** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3668** can be obtained by calling [sqlite3_reset()] on the 3669** [prepared statement]. ^In the "v2" interface, 3670** the more specific error code is returned directly by sqlite3_step(). 3671** 3672** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3673** Perhaps it was called on a [prepared statement] that has 3674** already been [sqlite3_finalize | finalized] or on one that had 3675** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3676** be the case that the same database connection is being used by two or 3677** more threads at the same moment in time. 3678** 3679** For all versions of SQLite up to and including 3.6.23.1, a call to 3680** [sqlite3_reset()] was required after sqlite3_step() returned anything 3681** other than [SQLITE_ROW] before any subsequent invocation of 3682** sqlite3_step(). Failure to reset the prepared statement using 3683** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3684** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3685** calling [sqlite3_reset()] automatically in this circumstance rather 3686** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3687** break because any application that ever receives an SQLITE_MISUSE error 3688** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3689** can be used to restore the legacy behavior. 3690** 3691** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3692** API always returns a generic error code, [SQLITE_ERROR], following any 3693** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3694** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3695** specific [error codes] that better describes the error. 3696** We admit that this is a goofy design. The problem has been fixed 3697** with the "v2" interface. If you prepare all of your SQL statements 3698** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3699** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3700** then the more specific [error codes] are returned directly 3701** by sqlite3_step(). The use of the "v2" interface is recommended. 3702*/ 3703int sqlite3_step(sqlite3_stmt*); 3704 3705/* 3706** CAPI3REF: Number of columns in a result set 3707** 3708** ^The sqlite3_data_count(P) interface returns the number of columns in the 3709** current row of the result set of [prepared statement] P. 3710** ^If prepared statement P does not have results ready to return 3711** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3712** interfaces) then sqlite3_data_count(P) returns 0. 3713** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3714** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3715** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3716** will return non-zero if previous call to [sqlite3_step](P) returned 3717** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3718** where it always returns zero since each step of that multi-step 3719** pragma returns 0 columns of data. 3720** 3721** See also: [sqlite3_column_count()] 3722*/ 3723int sqlite3_data_count(sqlite3_stmt *pStmt); 3724 3725/* 3726** CAPI3REF: Fundamental Datatypes 3727** KEYWORDS: SQLITE_TEXT 3728** 3729** ^(Every value in SQLite has one of five fundamental datatypes: 3730** 3731** <ul> 3732** <li> 64-bit signed integer 3733** <li> 64-bit IEEE floating point number 3734** <li> string 3735** <li> BLOB 3736** <li> NULL 3737** </ul>)^ 3738** 3739** These constants are codes for each of those types. 3740** 3741** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3742** for a completely different meaning. Software that links against both 3743** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3744** SQLITE_TEXT. 3745*/ 3746#define SQLITE_INTEGER 1 3747#define SQLITE_FLOAT 2 3748#define SQLITE_BLOB 4 3749#define SQLITE_NULL 5 3750#ifdef SQLITE_TEXT 3751# undef SQLITE_TEXT 3752#else 3753# define SQLITE_TEXT 3 3754#endif 3755#define SQLITE3_TEXT 3 3756 3757/* 3758** CAPI3REF: Result Values From A Query 3759** KEYWORDS: {column access functions} 3760** 3761** These routines form the "result set" interface. 3762** 3763** ^These routines return information about a single column of the current 3764** result row of a query. ^In every case the first argument is a pointer 3765** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3766** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3767** and the second argument is the index of the column for which information 3768** should be returned. ^The leftmost column of the result set has the index 0. 3769** ^The number of columns in the result can be determined using 3770** [sqlite3_column_count()]. 3771** 3772** If the SQL statement does not currently point to a valid row, or if the 3773** column index is out of range, the result is undefined. 3774** These routines may only be called when the most recent call to 3775** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3776** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3777** If any of these routines are called after [sqlite3_reset()] or 3778** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3779** something other than [SQLITE_ROW], the results are undefined. 3780** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3781** are called from a different thread while any of these routines 3782** are pending, then the results are undefined. 3783** 3784** ^The sqlite3_column_type() routine returns the 3785** [SQLITE_INTEGER | datatype code] for the initial data type 3786** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3787** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3788** returned by sqlite3_column_type() is only meaningful if no type 3789** conversions have occurred as described below. After a type conversion, 3790** the value returned by sqlite3_column_type() is undefined. Future 3791** versions of SQLite may change the behavior of sqlite3_column_type() 3792** following a type conversion. 3793** 3794** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3795** routine returns the number of bytes in that BLOB or string. 3796** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3797** the string to UTF-8 and then returns the number of bytes. 3798** ^If the result is a numeric value then sqlite3_column_bytes() uses 3799** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3800** the number of bytes in that string. 3801** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3802** 3803** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3804** routine returns the number of bytes in that BLOB or string. 3805** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3806** the string to UTF-16 and then returns the number of bytes. 3807** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3808** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3809** the number of bytes in that string. 3810** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3811** 3812** ^The values returned by [sqlite3_column_bytes()] and 3813** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3814** of the string. ^For clarity: the values returned by 3815** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3816** bytes in the string, not the number of characters. 3817** 3818** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3819** even empty strings, are always zero-terminated. ^The return 3820** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3821** 3822** ^The object returned by [sqlite3_column_value()] is an 3823** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3824** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3825** If the [unprotected sqlite3_value] object returned by 3826** [sqlite3_column_value()] is used in any other way, including calls 3827** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3828** or [sqlite3_value_bytes()], then the behavior is undefined. 3829** 3830** These routines attempt to convert the value where appropriate. ^For 3831** example, if the internal representation is FLOAT and a text result 3832** is requested, [sqlite3_snprintf()] is used internally to perform the 3833** conversion automatically. ^(The following table details the conversions 3834** that are applied: 3835** 3836** <blockquote> 3837** <table border="1"> 3838** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3839** 3840** <tr><td> NULL <td> INTEGER <td> Result is 0 3841** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3842** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 3843** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 3844** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3845** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3846** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3847** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 3848** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3849** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 3850** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 3851** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 3852** <tr><td> TEXT <td> BLOB <td> No change 3853** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 3854** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 3855** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3856** </table> 3857** </blockquote>)^ 3858** 3859** The table above makes reference to standard C library functions atoi() 3860** and atof(). SQLite does not really use these functions. It has its 3861** own equivalent internal routines. The atoi() and atof() names are 3862** used in the table for brevity and because they are familiar to most 3863** C programmers. 3864** 3865** Note that when type conversions occur, pointers returned by prior 3866** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3867** sqlite3_column_text16() may be invalidated. 3868** Type conversions and pointer invalidations might occur 3869** in the following cases: 3870** 3871** <ul> 3872** <li> The initial content is a BLOB and sqlite3_column_text() or 3873** sqlite3_column_text16() is called. A zero-terminator might 3874** need to be added to the string.</li> 3875** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3876** sqlite3_column_text16() is called. The content must be converted 3877** to UTF-16.</li> 3878** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3879** sqlite3_column_text() is called. The content must be converted 3880** to UTF-8.</li> 3881** </ul> 3882** 3883** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3884** not invalidate a prior pointer, though of course the content of the buffer 3885** that the prior pointer references will have been modified. Other kinds 3886** of conversion are done in place when it is possible, but sometimes they 3887** are not possible and in those cases prior pointers are invalidated. 3888** 3889** The safest and easiest to remember policy is to invoke these routines 3890** in one of the following ways: 3891** 3892** <ul> 3893** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3894** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3895** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3896** </ul> 3897** 3898** In other words, you should call sqlite3_column_text(), 3899** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3900** into the desired format, then invoke sqlite3_column_bytes() or 3901** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3902** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3903** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3904** with calls to sqlite3_column_bytes(). 3905** 3906** ^The pointers returned are valid until a type conversion occurs as 3907** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3908** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3909** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3910** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3911** [sqlite3_free()]. 3912** 3913** ^(If a memory allocation error occurs during the evaluation of any 3914** of these routines, a default value is returned. The default value 3915** is either the integer 0, the floating point number 0.0, or a NULL 3916** pointer. Subsequent calls to [sqlite3_errcode()] will return 3917** [SQLITE_NOMEM].)^ 3918*/ 3919const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3920int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3921int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3922double sqlite3_column_double(sqlite3_stmt*, int iCol); 3923int sqlite3_column_int(sqlite3_stmt*, int iCol); 3924sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3925const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3926const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3927int sqlite3_column_type(sqlite3_stmt*, int iCol); 3928sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3929 3930/* 3931** CAPI3REF: Destroy A Prepared Statement Object 3932** 3933** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3934** ^If the most recent evaluation of the statement encountered no errors 3935** or if the statement is never been evaluated, then sqlite3_finalize() returns 3936** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3937** sqlite3_finalize(S) returns the appropriate [error code] or 3938** [extended error code]. 3939** 3940** ^The sqlite3_finalize(S) routine can be called at any point during 3941** the life cycle of [prepared statement] S: 3942** before statement S is ever evaluated, after 3943** one or more calls to [sqlite3_reset()], or after any call 3944** to [sqlite3_step()] regardless of whether or not the statement has 3945** completed execution. 3946** 3947** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3948** 3949** The application must finalize every [prepared statement] in order to avoid 3950** resource leaks. It is a grievous error for the application to try to use 3951** a prepared statement after it has been finalized. Any use of a prepared 3952** statement after it has been finalized can result in undefined and 3953** undesirable behavior such as segfaults and heap corruption. 3954*/ 3955int sqlite3_finalize(sqlite3_stmt *pStmt); 3956 3957/* 3958** CAPI3REF: Reset A Prepared Statement Object 3959** 3960** The sqlite3_reset() function is called to reset a [prepared statement] 3961** object back to its initial state, ready to be re-executed. 3962** ^Any SQL statement variables that had values bound to them using 3963** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3964** Use [sqlite3_clear_bindings()] to reset the bindings. 3965** 3966** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3967** back to the beginning of its program. 3968** 3969** ^If the most recent call to [sqlite3_step(S)] for the 3970** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3971** or if [sqlite3_step(S)] has never before been called on S, 3972** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3973** 3974** ^If the most recent call to [sqlite3_step(S)] for the 3975** [prepared statement] S indicated an error, then 3976** [sqlite3_reset(S)] returns an appropriate [error code]. 3977** 3978** ^The [sqlite3_reset(S)] interface does not change the values 3979** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3980*/ 3981int sqlite3_reset(sqlite3_stmt *pStmt); 3982 3983/* 3984** CAPI3REF: Create Or Redefine SQL Functions 3985** KEYWORDS: {function creation routines} 3986** KEYWORDS: {application-defined SQL function} 3987** KEYWORDS: {application-defined SQL functions} 3988** 3989** ^These functions (collectively known as "function creation routines") 3990** are used to add SQL functions or aggregates or to redefine the behavior 3991** of existing SQL functions or aggregates. The only differences between 3992** these routines are the text encoding expected for 3993** the second parameter (the name of the function being created) 3994** and the presence or absence of a destructor callback for 3995** the application data pointer. 3996** 3997** ^The first parameter is the [database connection] to which the SQL 3998** function is to be added. ^If an application uses more than one database 3999** connection then application-defined SQL functions must be added 4000** to each database connection separately. 4001** 4002** ^The second parameter is the name of the SQL function to be created or 4003** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4004** representation, exclusive of the zero-terminator. ^Note that the name 4005** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4006** ^Any attempt to create a function with a longer name 4007** will result in [SQLITE_MISUSE] being returned. 4008** 4009** ^The third parameter (nArg) 4010** is the number of arguments that the SQL function or 4011** aggregate takes. ^If this parameter is -1, then the SQL function or 4012** aggregate may take any number of arguments between 0 and the limit 4013** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4014** parameter is less than -1 or greater than 127 then the behavior is 4015** undefined. 4016** 4017** ^The fourth parameter, eTextRep, specifies what 4018** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4019** its parameters. The application should set this parameter to 4020** [SQLITE_UTF16LE] if the function implementation invokes 4021** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4022** implementation invokes [sqlite3_value_text16be()] on an input, or 4023** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4024** otherwise. ^The same SQL function may be registered multiple times using 4025** different preferred text encodings, with different implementations for 4026** each encoding. 4027** ^When multiple implementations of the same function are available, SQLite 4028** will pick the one that involves the least amount of data conversion. 4029** 4030** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4031** to signal that the function will always return the same result given 4032** the same inputs within a single SQL statement. Most SQL functions are 4033** deterministic. The built-in [random()] SQL function is an example of a 4034** function that is not deterministic. The SQLite query planner is able to 4035** perform additional optimizations on deterministic functions, so use 4036** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4037** 4038** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4039** function can gain access to this pointer using [sqlite3_user_data()].)^ 4040** 4041** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4042** pointers to C-language functions that implement the SQL function or 4043** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4044** callback only; NULL pointers must be passed as the xStep and xFinal 4045** parameters. ^An aggregate SQL function requires an implementation of xStep 4046** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4047** SQL function or aggregate, pass NULL pointers for all three function 4048** callbacks. 4049** 4050** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4051** then it is destructor for the application data pointer. 4052** The destructor is invoked when the function is deleted, either by being 4053** overloaded or when the database connection closes.)^ 4054** ^The destructor is also invoked if the call to 4055** sqlite3_create_function_v2() fails. 4056** ^When the destructor callback of the tenth parameter is invoked, it 4057** is passed a single argument which is a copy of the application data 4058** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4059** 4060** ^It is permitted to register multiple implementations of the same 4061** functions with the same name but with either differing numbers of 4062** arguments or differing preferred text encodings. ^SQLite will use 4063** the implementation that most closely matches the way in which the 4064** SQL function is used. ^A function implementation with a non-negative 4065** nArg parameter is a better match than a function implementation with 4066** a negative nArg. ^A function where the preferred text encoding 4067** matches the database encoding is a better 4068** match than a function where the encoding is different. 4069** ^A function where the encoding difference is between UTF16le and UTF16be 4070** is a closer match than a function where the encoding difference is 4071** between UTF8 and UTF16. 4072** 4073** ^Built-in functions may be overloaded by new application-defined functions. 4074** 4075** ^An application-defined function is permitted to call other 4076** SQLite interfaces. However, such calls must not 4077** close the database connection nor finalize or reset the prepared 4078** statement in which the function is running. 4079*/ 4080int sqlite3_create_function( 4081 sqlite3 *db, 4082 const char *zFunctionName, 4083 int nArg, 4084 int eTextRep, 4085 void *pApp, 4086 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4087 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4088 void (*xFinal)(sqlite3_context*) 4089); 4090int sqlite3_create_function16( 4091 sqlite3 *db, 4092 const void *zFunctionName, 4093 int nArg, 4094 int eTextRep, 4095 void *pApp, 4096 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4097 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4098 void (*xFinal)(sqlite3_context*) 4099); 4100int sqlite3_create_function_v2( 4101 sqlite3 *db, 4102 const char *zFunctionName, 4103 int nArg, 4104 int eTextRep, 4105 void *pApp, 4106 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4107 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4108 void (*xFinal)(sqlite3_context*), 4109 void(*xDestroy)(void*) 4110); 4111 4112/* 4113** CAPI3REF: Text Encodings 4114** 4115** These constant define integer codes that represent the various 4116** text encodings supported by SQLite. 4117*/ 4118#define SQLITE_UTF8 1 4119#define SQLITE_UTF16LE 2 4120#define SQLITE_UTF16BE 3 4121#define SQLITE_UTF16 4 /* Use native byte order */ 4122#define SQLITE_ANY 5 /* Deprecated */ 4123#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4124 4125/* 4126** CAPI3REF: Function Flags 4127** 4128** These constants may be ORed together with the 4129** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4130** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4131** [sqlite3_create_function_v2()]. 4132*/ 4133#define SQLITE_DETERMINISTIC 0x800 4134 4135/* 4136** CAPI3REF: Deprecated Functions 4137** DEPRECATED 4138** 4139** These functions are [deprecated]. In order to maintain 4140** backwards compatibility with older code, these functions continue 4141** to be supported. However, new applications should avoid 4142** the use of these functions. To help encourage people to avoid 4143** using these functions, we are not going to tell you what they do. 4144*/ 4145#ifndef SQLITE_OMIT_DEPRECATED 4146SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4147SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4148SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4149SQLITE_DEPRECATED int sqlite3_global_recover(void); 4150SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4151SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4152 void*,sqlite3_int64); 4153#endif 4154 4155/* 4156** CAPI3REF: Obtaining SQL Function Parameter Values 4157** 4158** The C-language implementation of SQL functions and aggregates uses 4159** this set of interface routines to access the parameter values on 4160** the function or aggregate. 4161** 4162** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4163** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4164** define callbacks that implement the SQL functions and aggregates. 4165** The 3rd parameter to these callbacks is an array of pointers to 4166** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4167** each parameter to the SQL function. These routines are used to 4168** extract values from the [sqlite3_value] objects. 4169** 4170** These routines work only with [protected sqlite3_value] objects. 4171** Any attempt to use these routines on an [unprotected sqlite3_value] 4172** object results in undefined behavior. 4173** 4174** ^These routines work just like the corresponding [column access functions] 4175** except that these routines take a single [protected sqlite3_value] object 4176** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4177** 4178** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4179** in the native byte-order of the host machine. ^The 4180** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4181** extract UTF-16 strings as big-endian and little-endian respectively. 4182** 4183** ^(The sqlite3_value_numeric_type() interface attempts to apply 4184** numeric affinity to the value. This means that an attempt is 4185** made to convert the value to an integer or floating point. If 4186** such a conversion is possible without loss of information (in other 4187** words, if the value is a string that looks like a number) 4188** then the conversion is performed. Otherwise no conversion occurs. 4189** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4190** 4191** Please pay particular attention to the fact that the pointer returned 4192** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4193** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4194** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4195** or [sqlite3_value_text16()]. 4196** 4197** These routines must be called from the same thread as 4198** the SQL function that supplied the [sqlite3_value*] parameters. 4199*/ 4200const void *sqlite3_value_blob(sqlite3_value*); 4201int sqlite3_value_bytes(sqlite3_value*); 4202int sqlite3_value_bytes16(sqlite3_value*); 4203double sqlite3_value_double(sqlite3_value*); 4204int sqlite3_value_int(sqlite3_value*); 4205sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4206const unsigned char *sqlite3_value_text(sqlite3_value*); 4207const void *sqlite3_value_text16(sqlite3_value*); 4208const void *sqlite3_value_text16le(sqlite3_value*); 4209const void *sqlite3_value_text16be(sqlite3_value*); 4210int sqlite3_value_type(sqlite3_value*); 4211int sqlite3_value_numeric_type(sqlite3_value*); 4212 4213/* 4214** CAPI3REF: Obtain Aggregate Function Context 4215** 4216** Implementations of aggregate SQL functions use this 4217** routine to allocate memory for storing their state. 4218** 4219** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4220** for a particular aggregate function, SQLite 4221** allocates N of memory, zeroes out that memory, and returns a pointer 4222** to the new memory. ^On second and subsequent calls to 4223** sqlite3_aggregate_context() for the same aggregate function instance, 4224** the same buffer is returned. Sqlite3_aggregate_context() is normally 4225** called once for each invocation of the xStep callback and then one 4226** last time when the xFinal callback is invoked. ^(When no rows match 4227** an aggregate query, the xStep() callback of the aggregate function 4228** implementation is never called and xFinal() is called exactly once. 4229** In those cases, sqlite3_aggregate_context() might be called for the 4230** first time from within xFinal().)^ 4231** 4232** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4233** when first called if N is less than or equal to zero or if a memory 4234** allocate error occurs. 4235** 4236** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4237** determined by the N parameter on first successful call. Changing the 4238** value of N in subsequent call to sqlite3_aggregate_context() within 4239** the same aggregate function instance will not resize the memory 4240** allocation.)^ Within the xFinal callback, it is customary to set 4241** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4242** pointless memory allocations occur. 4243** 4244** ^SQLite automatically frees the memory allocated by 4245** sqlite3_aggregate_context() when the aggregate query concludes. 4246** 4247** The first parameter must be a copy of the 4248** [sqlite3_context | SQL function context] that is the first parameter 4249** to the xStep or xFinal callback routine that implements the aggregate 4250** function. 4251** 4252** This routine must be called from the same thread in which 4253** the aggregate SQL function is running. 4254*/ 4255void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4256 4257/* 4258** CAPI3REF: User Data For Functions 4259** 4260** ^The sqlite3_user_data() interface returns a copy of 4261** the pointer that was the pUserData parameter (the 5th parameter) 4262** of the [sqlite3_create_function()] 4263** and [sqlite3_create_function16()] routines that originally 4264** registered the application defined function. 4265** 4266** This routine must be called from the same thread in which 4267** the application-defined function is running. 4268*/ 4269void *sqlite3_user_data(sqlite3_context*); 4270 4271/* 4272** CAPI3REF: Database Connection For Functions 4273** 4274** ^The sqlite3_context_db_handle() interface returns a copy of 4275** the pointer to the [database connection] (the 1st parameter) 4276** of the [sqlite3_create_function()] 4277** and [sqlite3_create_function16()] routines that originally 4278** registered the application defined function. 4279*/ 4280sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4281 4282/* 4283** CAPI3REF: Function Auxiliary Data 4284** 4285** These functions may be used by (non-aggregate) SQL functions to 4286** associate metadata with argument values. If the same value is passed to 4287** multiple invocations of the same SQL function during query execution, under 4288** some circumstances the associated metadata may be preserved. An example 4289** of where this might be useful is in a regular-expression matching 4290** function. The compiled version of the regular expression can be stored as 4291** metadata associated with the pattern string. 4292** Then as long as the pattern string remains the same, 4293** the compiled regular expression can be reused on multiple 4294** invocations of the same function. 4295** 4296** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4297** associated by the sqlite3_set_auxdata() function with the Nth argument 4298** value to the application-defined function. ^If there is no metadata 4299** associated with the function argument, this sqlite3_get_auxdata() interface 4300** returns a NULL pointer. 4301** 4302** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4303** argument of the application-defined function. ^Subsequent 4304** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4305** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4306** NULL if the metadata has been discarded. 4307** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4308** SQLite will invoke the destructor function X with parameter P exactly 4309** once, when the metadata is discarded. 4310** SQLite is free to discard the metadata at any time, including: <ul> 4311** <li> when the corresponding function parameter changes, or 4312** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4313** SQL statement, or 4314** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or 4315** <li> during the original sqlite3_set_auxdata() call when a memory 4316** allocation error occurs. </ul>)^ 4317** 4318** Note the last bullet in particular. The destructor X in 4319** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4320** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4321** should be called near the end of the function implementation and the 4322** function implementation should not make any use of P after 4323** sqlite3_set_auxdata() has been called. 4324** 4325** ^(In practice, metadata is preserved between function calls for 4326** function parameters that are compile-time constants, including literal 4327** values and [parameters] and expressions composed from the same.)^ 4328** 4329** These routines must be called from the same thread in which 4330** the SQL function is running. 4331*/ 4332void *sqlite3_get_auxdata(sqlite3_context*, int N); 4333void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4334 4335 4336/* 4337** CAPI3REF: Constants Defining Special Destructor Behavior 4338** 4339** These are special values for the destructor that is passed in as the 4340** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4341** argument is SQLITE_STATIC, it means that the content pointer is constant 4342** and will never change. It does not need to be destroyed. ^The 4343** SQLITE_TRANSIENT value means that the content will likely change in 4344** the near future and that SQLite should make its own private copy of 4345** the content before returning. 4346** 4347** The typedef is necessary to work around problems in certain 4348** C++ compilers. 4349*/ 4350typedef void (*sqlite3_destructor_type)(void*); 4351#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4352#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4353 4354/* 4355** CAPI3REF: Setting The Result Of An SQL Function 4356** 4357** These routines are used by the xFunc or xFinal callbacks that 4358** implement SQL functions and aggregates. See 4359** [sqlite3_create_function()] and [sqlite3_create_function16()] 4360** for additional information. 4361** 4362** These functions work very much like the [parameter binding] family of 4363** functions used to bind values to host parameters in prepared statements. 4364** Refer to the [SQL parameter] documentation for additional information. 4365** 4366** ^The sqlite3_result_blob() interface sets the result from 4367** an application-defined function to be the BLOB whose content is pointed 4368** to by the second parameter and which is N bytes long where N is the 4369** third parameter. 4370** 4371** ^The sqlite3_result_zeroblob() interfaces set the result of 4372** the application-defined function to be a BLOB containing all zero 4373** bytes and N bytes in size, where N is the value of the 2nd parameter. 4374** 4375** ^The sqlite3_result_double() interface sets the result from 4376** an application-defined function to be a floating point value specified 4377** by its 2nd argument. 4378** 4379** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4380** cause the implemented SQL function to throw an exception. 4381** ^SQLite uses the string pointed to by the 4382** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4383** as the text of an error message. ^SQLite interprets the error 4384** message string from sqlite3_result_error() as UTF-8. ^SQLite 4385** interprets the string from sqlite3_result_error16() as UTF-16 in native 4386** byte order. ^If the third parameter to sqlite3_result_error() 4387** or sqlite3_result_error16() is negative then SQLite takes as the error 4388** message all text up through the first zero character. 4389** ^If the third parameter to sqlite3_result_error() or 4390** sqlite3_result_error16() is non-negative then SQLite takes that many 4391** bytes (not characters) from the 2nd parameter as the error message. 4392** ^The sqlite3_result_error() and sqlite3_result_error16() 4393** routines make a private copy of the error message text before 4394** they return. Hence, the calling function can deallocate or 4395** modify the text after they return without harm. 4396** ^The sqlite3_result_error_code() function changes the error code 4397** returned by SQLite as a result of an error in a function. ^By default, 4398** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4399** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4400** 4401** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4402** error indicating that a string or BLOB is too long to represent. 4403** 4404** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4405** error indicating that a memory allocation failed. 4406** 4407** ^The sqlite3_result_int() interface sets the return value 4408** of the application-defined function to be the 32-bit signed integer 4409** value given in the 2nd argument. 4410** ^The sqlite3_result_int64() interface sets the return value 4411** of the application-defined function to be the 64-bit signed integer 4412** value given in the 2nd argument. 4413** 4414** ^The sqlite3_result_null() interface sets the return value 4415** of the application-defined function to be NULL. 4416** 4417** ^The sqlite3_result_text(), sqlite3_result_text16(), 4418** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4419** set the return value of the application-defined function to be 4420** a text string which is represented as UTF-8, UTF-16 native byte order, 4421** UTF-16 little endian, or UTF-16 big endian, respectively. 4422** ^SQLite takes the text result from the application from 4423** the 2nd parameter of the sqlite3_result_text* interfaces. 4424** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4425** is negative, then SQLite takes result text from the 2nd parameter 4426** through the first zero character. 4427** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4428** is non-negative, then as many bytes (not characters) of the text 4429** pointed to by the 2nd parameter are taken as the application-defined 4430** function result. If the 3rd parameter is non-negative, then it 4431** must be the byte offset into the string where the NUL terminator would 4432** appear if the string where NUL terminated. If any NUL characters occur 4433** in the string at a byte offset that is less than the value of the 3rd 4434** parameter, then the resulting string will contain embedded NULs and the 4435** result of expressions operating on strings with embedded NULs is undefined. 4436** ^If the 4th parameter to the sqlite3_result_text* interfaces 4437** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4438** function as the destructor on the text or BLOB result when it has 4439** finished using that result. 4440** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4441** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4442** assumes that the text or BLOB result is in constant space and does not 4443** copy the content of the parameter nor call a destructor on the content 4444** when it has finished using that result. 4445** ^If the 4th parameter to the sqlite3_result_text* interfaces 4446** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4447** then SQLite makes a copy of the result into space obtained from 4448** from [sqlite3_malloc()] before it returns. 4449** 4450** ^The sqlite3_result_value() interface sets the result of 4451** the application-defined function to be a copy the 4452** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4453** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4454** so that the [sqlite3_value] specified in the parameter may change or 4455** be deallocated after sqlite3_result_value() returns without harm. 4456** ^A [protected sqlite3_value] object may always be used where an 4457** [unprotected sqlite3_value] object is required, so either 4458** kind of [sqlite3_value] object can be used with this interface. 4459** 4460** If these routines are called from within the different thread 4461** than the one containing the application-defined function that received 4462** the [sqlite3_context] pointer, the results are undefined. 4463*/ 4464void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4465void sqlite3_result_double(sqlite3_context*, double); 4466void sqlite3_result_error(sqlite3_context*, const char*, int); 4467void sqlite3_result_error16(sqlite3_context*, const void*, int); 4468void sqlite3_result_error_toobig(sqlite3_context*); 4469void sqlite3_result_error_nomem(sqlite3_context*); 4470void sqlite3_result_error_code(sqlite3_context*, int); 4471void sqlite3_result_int(sqlite3_context*, int); 4472void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4473void sqlite3_result_null(sqlite3_context*); 4474void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4475void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4476void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4477void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4478void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4479void sqlite3_result_zeroblob(sqlite3_context*, int n); 4480 4481/* 4482** CAPI3REF: Define New Collating Sequences 4483** 4484** ^These functions add, remove, or modify a [collation] associated 4485** with the [database connection] specified as the first argument. 4486** 4487** ^The name of the collation is a UTF-8 string 4488** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4489** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4490** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4491** considered to be the same name. 4492** 4493** ^(The third argument (eTextRep) must be one of the constants: 4494** <ul> 4495** <li> [SQLITE_UTF8], 4496** <li> [SQLITE_UTF16LE], 4497** <li> [SQLITE_UTF16BE], 4498** <li> [SQLITE_UTF16], or 4499** <li> [SQLITE_UTF16_ALIGNED]. 4500** </ul>)^ 4501** ^The eTextRep argument determines the encoding of strings passed 4502** to the collating function callback, xCallback. 4503** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4504** force strings to be UTF16 with native byte order. 4505** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4506** on an even byte address. 4507** 4508** ^The fourth argument, pArg, is an application data pointer that is passed 4509** through as the first argument to the collating function callback. 4510** 4511** ^The fifth argument, xCallback, is a pointer to the collating function. 4512** ^Multiple collating functions can be registered using the same name but 4513** with different eTextRep parameters and SQLite will use whichever 4514** function requires the least amount of data transformation. 4515** ^If the xCallback argument is NULL then the collating function is 4516** deleted. ^When all collating functions having the same name are deleted, 4517** that collation is no longer usable. 4518** 4519** ^The collating function callback is invoked with a copy of the pArg 4520** application data pointer and with two strings in the encoding specified 4521** by the eTextRep argument. The collating function must return an 4522** integer that is negative, zero, or positive 4523** if the first string is less than, equal to, or greater than the second, 4524** respectively. A collating function must always return the same answer 4525** given the same inputs. If two or more collating functions are registered 4526** to the same collation name (using different eTextRep values) then all 4527** must give an equivalent answer when invoked with equivalent strings. 4528** The collating function must obey the following properties for all 4529** strings A, B, and C: 4530** 4531** <ol> 4532** <li> If A==B then B==A. 4533** <li> If A==B and B==C then A==C. 4534** <li> If A<B THEN B>A. 4535** <li> If A<B and B<C then A<C. 4536** </ol> 4537** 4538** If a collating function fails any of the above constraints and that 4539** collating function is registered and used, then the behavior of SQLite 4540** is undefined. 4541** 4542** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4543** with the addition that the xDestroy callback is invoked on pArg when 4544** the collating function is deleted. 4545** ^Collating functions are deleted when they are overridden by later 4546** calls to the collation creation functions or when the 4547** [database connection] is closed using [sqlite3_close()]. 4548** 4549** ^The xDestroy callback is <u>not</u> called if the 4550** sqlite3_create_collation_v2() function fails. Applications that invoke 4551** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4552** check the return code and dispose of the application data pointer 4553** themselves rather than expecting SQLite to deal with it for them. 4554** This is different from every other SQLite interface. The inconsistency 4555** is unfortunate but cannot be changed without breaking backwards 4556** compatibility. 4557** 4558** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4559*/ 4560int sqlite3_create_collation( 4561 sqlite3*, 4562 const char *zName, 4563 int eTextRep, 4564 void *pArg, 4565 int(*xCompare)(void*,int,const void*,int,const void*) 4566); 4567int sqlite3_create_collation_v2( 4568 sqlite3*, 4569 const char *zName, 4570 int eTextRep, 4571 void *pArg, 4572 int(*xCompare)(void*,int,const void*,int,const void*), 4573 void(*xDestroy)(void*) 4574); 4575int sqlite3_create_collation16( 4576 sqlite3*, 4577 const void *zName, 4578 int eTextRep, 4579 void *pArg, 4580 int(*xCompare)(void*,int,const void*,int,const void*) 4581); 4582 4583/* 4584** CAPI3REF: Collation Needed Callbacks 4585** 4586** ^To avoid having to register all collation sequences before a database 4587** can be used, a single callback function may be registered with the 4588** [database connection] to be invoked whenever an undefined collation 4589** sequence is required. 4590** 4591** ^If the function is registered using the sqlite3_collation_needed() API, 4592** then it is passed the names of undefined collation sequences as strings 4593** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4594** the names are passed as UTF-16 in machine native byte order. 4595** ^A call to either function replaces the existing collation-needed callback. 4596** 4597** ^(When the callback is invoked, the first argument passed is a copy 4598** of the second argument to sqlite3_collation_needed() or 4599** sqlite3_collation_needed16(). The second argument is the database 4600** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4601** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4602** sequence function required. The fourth parameter is the name of the 4603** required collation sequence.)^ 4604** 4605** The callback function should register the desired collation using 4606** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4607** [sqlite3_create_collation_v2()]. 4608*/ 4609int sqlite3_collation_needed( 4610 sqlite3*, 4611 void*, 4612 void(*)(void*,sqlite3*,int eTextRep,const char*) 4613); 4614int sqlite3_collation_needed16( 4615 sqlite3*, 4616 void*, 4617 void(*)(void*,sqlite3*,int eTextRep,const void*) 4618); 4619 4620#ifdef SQLITE_HAS_CODEC 4621/* 4622** Specify the key for an encrypted database. This routine should be 4623** called right after sqlite3_open(). 4624** 4625** The code to implement this API is not available in the public release 4626** of SQLite. 4627*/ 4628int sqlite3_key( 4629 sqlite3 *db, /* Database to be rekeyed */ 4630 const void *pKey, int nKey /* The key */ 4631); 4632int sqlite3_key_v2( 4633 sqlite3 *db, /* Database to be rekeyed */ 4634 const char *zDbName, /* Name of the database */ 4635 const void *pKey, int nKey /* The key */ 4636); 4637 4638/* 4639** Change the key on an open database. If the current database is not 4640** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4641** database is decrypted. 4642** 4643** The code to implement this API is not available in the public release 4644** of SQLite. 4645*/ 4646int sqlite3_rekey( 4647 sqlite3 *db, /* Database to be rekeyed */ 4648 const void *pKey, int nKey /* The new key */ 4649); 4650int sqlite3_rekey_v2( 4651 sqlite3 *db, /* Database to be rekeyed */ 4652 const char *zDbName, /* Name of the database */ 4653 const void *pKey, int nKey /* The new key */ 4654); 4655 4656/* 4657** Specify the activation key for a SEE database. Unless 4658** activated, none of the SEE routines will work. 4659*/ 4660void sqlite3_activate_see( 4661 const char *zPassPhrase /* Activation phrase */ 4662); 4663#endif 4664 4665#ifdef SQLITE_ENABLE_CEROD 4666/* 4667** Specify the activation key for a CEROD database. Unless 4668** activated, none of the CEROD routines will work. 4669*/ 4670void sqlite3_activate_cerod( 4671 const char *zPassPhrase /* Activation phrase */ 4672); 4673#endif 4674 4675/* 4676** CAPI3REF: Suspend Execution For A Short Time 4677** 4678** The sqlite3_sleep() function causes the current thread to suspend execution 4679** for at least a number of milliseconds specified in its parameter. 4680** 4681** If the operating system does not support sleep requests with 4682** millisecond time resolution, then the time will be rounded up to 4683** the nearest second. The number of milliseconds of sleep actually 4684** requested from the operating system is returned. 4685** 4686** ^SQLite implements this interface by calling the xSleep() 4687** method of the default [sqlite3_vfs] object. If the xSleep() method 4688** of the default VFS is not implemented correctly, or not implemented at 4689** all, then the behavior of sqlite3_sleep() may deviate from the description 4690** in the previous paragraphs. 4691*/ 4692int sqlite3_sleep(int); 4693 4694/* 4695** CAPI3REF: Name Of The Folder Holding Temporary Files 4696** 4697** ^(If this global variable is made to point to a string which is 4698** the name of a folder (a.k.a. directory), then all temporary files 4699** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4700** will be placed in that directory.)^ ^If this variable 4701** is a NULL pointer, then SQLite performs a search for an appropriate 4702** temporary file directory. 4703** 4704** It is not safe to read or modify this variable in more than one 4705** thread at a time. It is not safe to read or modify this variable 4706** if a [database connection] is being used at the same time in a separate 4707** thread. 4708** It is intended that this variable be set once 4709** as part of process initialization and before any SQLite interface 4710** routines have been called and that this variable remain unchanged 4711** thereafter. 4712** 4713** ^The [temp_store_directory pragma] may modify this variable and cause 4714** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4715** the [temp_store_directory pragma] always assumes that any string 4716** that this variable points to is held in memory obtained from 4717** [sqlite3_malloc] and the pragma may attempt to free that memory 4718** using [sqlite3_free]. 4719** Hence, if this variable is modified directly, either it should be 4720** made NULL or made to point to memory obtained from [sqlite3_malloc] 4721** or else the use of the [temp_store_directory pragma] should be avoided. 4722** 4723** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4724** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4725** features that require the use of temporary files may fail. Here is an 4726** example of how to do this using C++ with the Windows Runtime: 4727** 4728** <blockquote><pre> 4729** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4730** TemporaryFolder->Path->Data(); 4731** char zPathBuf[MAX_PATH + 1]; 4732** memset(zPathBuf, 0, sizeof(zPathBuf)); 4733** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4734** NULL, NULL); 4735** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4736** </pre></blockquote> 4737*/ 4738SQLITE_EXTERN char *sqlite3_temp_directory; 4739 4740/* 4741** CAPI3REF: Name Of The Folder Holding Database Files 4742** 4743** ^(If this global variable is made to point to a string which is 4744** the name of a folder (a.k.a. directory), then all database files 4745** specified with a relative pathname and created or accessed by 4746** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4747** to be relative to that directory.)^ ^If this variable is a NULL 4748** pointer, then SQLite assumes that all database files specified 4749** with a relative pathname are relative to the current directory 4750** for the process. Only the windows VFS makes use of this global 4751** variable; it is ignored by the unix VFS. 4752** 4753** Changing the value of this variable while a database connection is 4754** open can result in a corrupt database. 4755** 4756** It is not safe to read or modify this variable in more than one 4757** thread at a time. It is not safe to read or modify this variable 4758** if a [database connection] is being used at the same time in a separate 4759** thread. 4760** It is intended that this variable be set once 4761** as part of process initialization and before any SQLite interface 4762** routines have been called and that this variable remain unchanged 4763** thereafter. 4764** 4765** ^The [data_store_directory pragma] may modify this variable and cause 4766** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4767** the [data_store_directory pragma] always assumes that any string 4768** that this variable points to is held in memory obtained from 4769** [sqlite3_malloc] and the pragma may attempt to free that memory 4770** using [sqlite3_free]. 4771** Hence, if this variable is modified directly, either it should be 4772** made NULL or made to point to memory obtained from [sqlite3_malloc] 4773** or else the use of the [data_store_directory pragma] should be avoided. 4774*/ 4775SQLITE_EXTERN char *sqlite3_data_directory; 4776 4777/* 4778** CAPI3REF: Test For Auto-Commit Mode 4779** KEYWORDS: {autocommit mode} 4780** 4781** ^The sqlite3_get_autocommit() interface returns non-zero or 4782** zero if the given database connection is or is not in autocommit mode, 4783** respectively. ^Autocommit mode is on by default. 4784** ^Autocommit mode is disabled by a [BEGIN] statement. 4785** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4786** 4787** If certain kinds of errors occur on a statement within a multi-statement 4788** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4789** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4790** transaction might be rolled back automatically. The only way to 4791** find out whether SQLite automatically rolled back the transaction after 4792** an error is to use this function. 4793** 4794** If another thread changes the autocommit status of the database 4795** connection while this routine is running, then the return value 4796** is undefined. 4797*/ 4798int sqlite3_get_autocommit(sqlite3*); 4799 4800/* 4801** CAPI3REF: Find The Database Handle Of A Prepared Statement 4802** 4803** ^The sqlite3_db_handle interface returns the [database connection] handle 4804** to which a [prepared statement] belongs. ^The [database connection] 4805** returned by sqlite3_db_handle is the same [database connection] 4806** that was the first argument 4807** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4808** create the statement in the first place. 4809*/ 4810sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4811 4812/* 4813** CAPI3REF: Return The Filename For A Database Connection 4814** 4815** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4816** associated with database N of connection D. ^The main database file 4817** has the name "main". If there is no attached database N on the database 4818** connection D, or if database N is a temporary or in-memory database, then 4819** a NULL pointer is returned. 4820** 4821** ^The filename returned by this function is the output of the 4822** xFullPathname method of the [VFS]. ^In other words, the filename 4823** will be an absolute pathname, even if the filename used 4824** to open the database originally was a URI or relative pathname. 4825*/ 4826const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4827 4828/* 4829** CAPI3REF: Determine if a database is read-only 4830** 4831** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4832** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4833** the name of a database on connection D. 4834*/ 4835int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4836 4837/* 4838** CAPI3REF: Find the next prepared statement 4839** 4840** ^This interface returns a pointer to the next [prepared statement] after 4841** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4842** then this interface returns a pointer to the first prepared statement 4843** associated with the database connection pDb. ^If no prepared statement 4844** satisfies the conditions of this routine, it returns NULL. 4845** 4846** The [database connection] pointer D in a call to 4847** [sqlite3_next_stmt(D,S)] must refer to an open database 4848** connection and in particular must not be a NULL pointer. 4849*/ 4850sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4851 4852/* 4853** CAPI3REF: Commit And Rollback Notification Callbacks 4854** 4855** ^The sqlite3_commit_hook() interface registers a callback 4856** function to be invoked whenever a transaction is [COMMIT | committed]. 4857** ^Any callback set by a previous call to sqlite3_commit_hook() 4858** for the same database connection is overridden. 4859** ^The sqlite3_rollback_hook() interface registers a callback 4860** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4861** ^Any callback set by a previous call to sqlite3_rollback_hook() 4862** for the same database connection is overridden. 4863** ^The pArg argument is passed through to the callback. 4864** ^If the callback on a commit hook function returns non-zero, 4865** then the commit is converted into a rollback. 4866** 4867** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4868** return the P argument from the previous call of the same function 4869** on the same [database connection] D, or NULL for 4870** the first call for each function on D. 4871** 4872** The commit and rollback hook callbacks are not reentrant. 4873** The callback implementation must not do anything that will modify 4874** the database connection that invoked the callback. Any actions 4875** to modify the database connection must be deferred until after the 4876** completion of the [sqlite3_step()] call that triggered the commit 4877** or rollback hook in the first place. 4878** Note that running any other SQL statements, including SELECT statements, 4879** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4880** the database connections for the meaning of "modify" in this paragraph. 4881** 4882** ^Registering a NULL function disables the callback. 4883** 4884** ^When the commit hook callback routine returns zero, the [COMMIT] 4885** operation is allowed to continue normally. ^If the commit hook 4886** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4887** ^The rollback hook is invoked on a rollback that results from a commit 4888** hook returning non-zero, just as it would be with any other rollback. 4889** 4890** ^For the purposes of this API, a transaction is said to have been 4891** rolled back if an explicit "ROLLBACK" statement is executed, or 4892** an error or constraint causes an implicit rollback to occur. 4893** ^The rollback callback is not invoked if a transaction is 4894** automatically rolled back because the database connection is closed. 4895** 4896** See also the [sqlite3_update_hook()] interface. 4897*/ 4898void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4899void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4900 4901/* 4902** CAPI3REF: Data Change Notification Callbacks 4903** 4904** ^The sqlite3_update_hook() interface registers a callback function 4905** with the [database connection] identified by the first argument 4906** to be invoked whenever a row is updated, inserted or deleted in 4907** a rowid table. 4908** ^Any callback set by a previous call to this function 4909** for the same database connection is overridden. 4910** 4911** ^The second argument is a pointer to the function to invoke when a 4912** row is updated, inserted or deleted in a rowid table. 4913** ^The first argument to the callback is a copy of the third argument 4914** to sqlite3_update_hook(). 4915** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4916** or [SQLITE_UPDATE], depending on the operation that caused the callback 4917** to be invoked. 4918** ^The third and fourth arguments to the callback contain pointers to the 4919** database and table name containing the affected row. 4920** ^The final callback parameter is the [rowid] of the row. 4921** ^In the case of an update, this is the [rowid] after the update takes place. 4922** 4923** ^(The update hook is not invoked when internal system tables are 4924** modified (i.e. sqlite_master and sqlite_sequence).)^ 4925** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 4926** 4927** ^In the current implementation, the update hook 4928** is not invoked when duplication rows are deleted because of an 4929** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4930** invoked when rows are deleted using the [truncate optimization]. 4931** The exceptions defined in this paragraph might change in a future 4932** release of SQLite. 4933** 4934** The update hook implementation must not do anything that will modify 4935** the database connection that invoked the update hook. Any actions 4936** to modify the database connection must be deferred until after the 4937** completion of the [sqlite3_step()] call that triggered the update hook. 4938** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4939** database connections for the meaning of "modify" in this paragraph. 4940** 4941** ^The sqlite3_update_hook(D,C,P) function 4942** returns the P argument from the previous call 4943** on the same [database connection] D, or NULL for 4944** the first call on D. 4945** 4946** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4947** interfaces. 4948*/ 4949void *sqlite3_update_hook( 4950 sqlite3*, 4951 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4952 void* 4953); 4954 4955/* 4956** CAPI3REF: Enable Or Disable Shared Pager Cache 4957** 4958** ^(This routine enables or disables the sharing of the database cache 4959** and schema data structures between [database connection | connections] 4960** to the same database. Sharing is enabled if the argument is true 4961** and disabled if the argument is false.)^ 4962** 4963** ^Cache sharing is enabled and disabled for an entire process. 4964** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4965** sharing was enabled or disabled for each thread separately. 4966** 4967** ^(The cache sharing mode set by this interface effects all subsequent 4968** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4969** Existing database connections continue use the sharing mode 4970** that was in effect at the time they were opened.)^ 4971** 4972** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4973** successfully. An [error code] is returned otherwise.)^ 4974** 4975** ^Shared cache is disabled by default. But this might change in 4976** future releases of SQLite. Applications that care about shared 4977** cache setting should set it explicitly. 4978** 4979** This interface is threadsafe on processors where writing a 4980** 32-bit integer is atomic. 4981** 4982** See Also: [SQLite Shared-Cache Mode] 4983*/ 4984int sqlite3_enable_shared_cache(int); 4985 4986/* 4987** CAPI3REF: Attempt To Free Heap Memory 4988** 4989** ^The sqlite3_release_memory() interface attempts to free N bytes 4990** of heap memory by deallocating non-essential memory allocations 4991** held by the database library. Memory used to cache database 4992** pages to improve performance is an example of non-essential memory. 4993** ^sqlite3_release_memory() returns the number of bytes actually freed, 4994** which might be more or less than the amount requested. 4995** ^The sqlite3_release_memory() routine is a no-op returning zero 4996** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4997** 4998** See also: [sqlite3_db_release_memory()] 4999*/ 5000int sqlite3_release_memory(int); 5001 5002/* 5003** CAPI3REF: Free Memory Used By A Database Connection 5004** 5005** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5006** memory as possible from database connection D. Unlike the 5007** [sqlite3_release_memory()] interface, this interface is in effect even 5008** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5009** omitted. 5010** 5011** See also: [sqlite3_release_memory()] 5012*/ 5013int sqlite3_db_release_memory(sqlite3*); 5014 5015/* 5016** CAPI3REF: Impose A Limit On Heap Size 5017** 5018** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5019** soft limit on the amount of heap memory that may be allocated by SQLite. 5020** ^SQLite strives to keep heap memory utilization below the soft heap 5021** limit by reducing the number of pages held in the page cache 5022** as heap memory usages approaches the limit. 5023** ^The soft heap limit is "soft" because even though SQLite strives to stay 5024** below the limit, it will exceed the limit rather than generate 5025** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5026** is advisory only. 5027** 5028** ^The return value from sqlite3_soft_heap_limit64() is the size of 5029** the soft heap limit prior to the call, or negative in the case of an 5030** error. ^If the argument N is negative 5031** then no change is made to the soft heap limit. Hence, the current 5032** size of the soft heap limit can be determined by invoking 5033** sqlite3_soft_heap_limit64() with a negative argument. 5034** 5035** ^If the argument N is zero then the soft heap limit is disabled. 5036** 5037** ^(The soft heap limit is not enforced in the current implementation 5038** if one or more of following conditions are true: 5039** 5040** <ul> 5041** <li> The soft heap limit is set to zero. 5042** <li> Memory accounting is disabled using a combination of the 5043** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5044** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5045** <li> An alternative page cache implementation is specified using 5046** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5047** <li> The page cache allocates from its own memory pool supplied 5048** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5049** from the heap. 5050** </ul>)^ 5051** 5052** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 5053** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5054** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5055** the soft heap limit is enforced on every memory allocation. Without 5056** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5057** when memory is allocated by the page cache. Testing suggests that because 5058** the page cache is the predominate memory user in SQLite, most 5059** applications will achieve adequate soft heap limit enforcement without 5060** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5061** 5062** The circumstances under which SQLite will enforce the soft heap limit may 5063** changes in future releases of SQLite. 5064*/ 5065sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5066 5067/* 5068** CAPI3REF: Deprecated Soft Heap Limit Interface 5069** DEPRECATED 5070** 5071** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5072** interface. This routine is provided for historical compatibility 5073** only. All new applications should use the 5074** [sqlite3_soft_heap_limit64()] interface rather than this one. 5075*/ 5076SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5077 5078 5079/* 5080** CAPI3REF: Extract Metadata About A Column Of A Table 5081** 5082** ^This routine returns metadata about a specific column of a specific 5083** database table accessible using the [database connection] handle 5084** passed as the first function argument. 5085** 5086** ^The column is identified by the second, third and fourth parameters to 5087** this function. ^The second parameter is either the name of the database 5088** (i.e. "main", "temp", or an attached database) containing the specified 5089** table or NULL. ^If it is NULL, then all attached databases are searched 5090** for the table using the same algorithm used by the database engine to 5091** resolve unqualified table references. 5092** 5093** ^The third and fourth parameters to this function are the table and column 5094** name of the desired column, respectively. Neither of these parameters 5095** may be NULL. 5096** 5097** ^Metadata is returned by writing to the memory locations passed as the 5th 5098** and subsequent parameters to this function. ^Any of these arguments may be 5099** NULL, in which case the corresponding element of metadata is omitted. 5100** 5101** ^(<blockquote> 5102** <table border="1"> 5103** <tr><th> Parameter <th> Output<br>Type <th> Description 5104** 5105** <tr><td> 5th <td> const char* <td> Data type 5106** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5107** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5108** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5109** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5110** </table> 5111** </blockquote>)^ 5112** 5113** ^The memory pointed to by the character pointers returned for the 5114** declaration type and collation sequence is valid only until the next 5115** call to any SQLite API function. 5116** 5117** ^If the specified table is actually a view, an [error code] is returned. 5118** 5119** ^If the specified column is "rowid", "oid" or "_rowid_" and an 5120** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5121** parameters are set for the explicitly declared column. ^(If there is no 5122** explicitly declared [INTEGER PRIMARY KEY] column, then the output 5123** parameters are set as follows: 5124** 5125** <pre> 5126** data type: "INTEGER" 5127** collation sequence: "BINARY" 5128** not null: 0 5129** primary key: 1 5130** auto increment: 0 5131** </pre>)^ 5132** 5133** ^(This function may load one or more schemas from database files. If an 5134** error occurs during this process, or if the requested table or column 5135** cannot be found, an [error code] is returned and an error message left 5136** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 5137** 5138** ^This API is only available if the library was compiled with the 5139** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 5140*/ 5141int sqlite3_table_column_metadata( 5142 sqlite3 *db, /* Connection handle */ 5143 const char *zDbName, /* Database name or NULL */ 5144 const char *zTableName, /* Table name */ 5145 const char *zColumnName, /* Column name */ 5146 char const **pzDataType, /* OUTPUT: Declared data type */ 5147 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5148 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5149 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5150 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5151); 5152 5153/* 5154** CAPI3REF: Load An Extension 5155** 5156** ^This interface loads an SQLite extension library from the named file. 5157** 5158** ^The sqlite3_load_extension() interface attempts to load an 5159** [SQLite extension] library contained in the file zFile. If 5160** the file cannot be loaded directly, attempts are made to load 5161** with various operating-system specific extensions added. 5162** So for example, if "samplelib" cannot be loaded, then names like 5163** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5164** be tried also. 5165** 5166** ^The entry point is zProc. 5167** ^(zProc may be 0, in which case SQLite will try to come up with an 5168** entry point name on its own. It first tries "sqlite3_extension_init". 5169** If that does not work, it constructs a name "sqlite3_X_init" where the 5170** X is consists of the lower-case equivalent of all ASCII alphabetic 5171** characters in the filename from the last "/" to the first following 5172** "." and omitting any initial "lib".)^ 5173** ^The sqlite3_load_extension() interface returns 5174** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5175** ^If an error occurs and pzErrMsg is not 0, then the 5176** [sqlite3_load_extension()] interface shall attempt to 5177** fill *pzErrMsg with error message text stored in memory 5178** obtained from [sqlite3_malloc()]. The calling function 5179** should free this memory by calling [sqlite3_free()]. 5180** 5181** ^Extension loading must be enabled using 5182** [sqlite3_enable_load_extension()] prior to calling this API, 5183** otherwise an error will be returned. 5184** 5185** See also the [load_extension() SQL function]. 5186*/ 5187int sqlite3_load_extension( 5188 sqlite3 *db, /* Load the extension into this database connection */ 5189 const char *zFile, /* Name of the shared library containing extension */ 5190 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5191 char **pzErrMsg /* Put error message here if not 0 */ 5192); 5193 5194/* 5195** CAPI3REF: Enable Or Disable Extension Loading 5196** 5197** ^So as not to open security holes in older applications that are 5198** unprepared to deal with [extension loading], and as a means of disabling 5199** [extension loading] while evaluating user-entered SQL, the following API 5200** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5201** 5202** ^Extension loading is off by default. 5203** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5204** to turn extension loading on and call it with onoff==0 to turn 5205** it back off again. 5206*/ 5207int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5208 5209/* 5210** CAPI3REF: Automatically Load Statically Linked Extensions 5211** 5212** ^This interface causes the xEntryPoint() function to be invoked for 5213** each new [database connection] that is created. The idea here is that 5214** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5215** that is to be automatically loaded into all new database connections. 5216** 5217** ^(Even though the function prototype shows that xEntryPoint() takes 5218** no arguments and returns void, SQLite invokes xEntryPoint() with three 5219** arguments and expects and integer result as if the signature of the 5220** entry point where as follows: 5221** 5222** <blockquote><pre> 5223** int xEntryPoint( 5224** sqlite3 *db, 5225** const char **pzErrMsg, 5226** const struct sqlite3_api_routines *pThunk 5227** ); 5228** </pre></blockquote>)^ 5229** 5230** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5231** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5232** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5233** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5234** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5235** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5236** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5237** 5238** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5239** on the list of automatic extensions is a harmless no-op. ^No entry point 5240** will be called more than once for each database connection that is opened. 5241** 5242** See also: [sqlite3_reset_auto_extension()] 5243** and [sqlite3_cancel_auto_extension()] 5244*/ 5245int sqlite3_auto_extension(void (*xEntryPoint)(void)); 5246 5247/* 5248** CAPI3REF: Cancel Automatic Extension Loading 5249** 5250** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5251** initialization routine X that was registered using a prior call to 5252** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5253** routine returns 1 if initialization routine X was successfully 5254** unregistered and it returns 0 if X was not on the list of initialization 5255** routines. 5256*/ 5257int sqlite3_cancel_auto_extension(void (*xEntryPoint)(void)); 5258 5259/* 5260** CAPI3REF: Reset Automatic Extension Loading 5261** 5262** ^This interface disables all automatic extensions previously 5263** registered using [sqlite3_auto_extension()]. 5264*/ 5265void sqlite3_reset_auto_extension(void); 5266 5267/* 5268** The interface to the virtual-table mechanism is currently considered 5269** to be experimental. The interface might change in incompatible ways. 5270** If this is a problem for you, do not use the interface at this time. 5271** 5272** When the virtual-table mechanism stabilizes, we will declare the 5273** interface fixed, support it indefinitely, and remove this comment. 5274*/ 5275 5276/* 5277** Structures used by the virtual table interface 5278*/ 5279typedef struct sqlite3_vtab sqlite3_vtab; 5280typedef struct sqlite3_index_info sqlite3_index_info; 5281typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5282typedef struct sqlite3_module sqlite3_module; 5283 5284/* 5285** CAPI3REF: Virtual Table Object 5286** KEYWORDS: sqlite3_module {virtual table module} 5287** 5288** This structure, sometimes called a "virtual table module", 5289** defines the implementation of a [virtual tables]. 5290** This structure consists mostly of methods for the module. 5291** 5292** ^A virtual table module is created by filling in a persistent 5293** instance of this structure and passing a pointer to that instance 5294** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5295** ^The registration remains valid until it is replaced by a different 5296** module or until the [database connection] closes. The content 5297** of this structure must not change while it is registered with 5298** any database connection. 5299*/ 5300struct sqlite3_module { 5301 int iVersion; 5302 int (*xCreate)(sqlite3*, void *pAux, 5303 int argc, const char *const*argv, 5304 sqlite3_vtab **ppVTab, char**); 5305 int (*xConnect)(sqlite3*, void *pAux, 5306 int argc, const char *const*argv, 5307 sqlite3_vtab **ppVTab, char**); 5308 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5309 int (*xDisconnect)(sqlite3_vtab *pVTab); 5310 int (*xDestroy)(sqlite3_vtab *pVTab); 5311 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5312 int (*xClose)(sqlite3_vtab_cursor*); 5313 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5314 int argc, sqlite3_value **argv); 5315 int (*xNext)(sqlite3_vtab_cursor*); 5316 int (*xEof)(sqlite3_vtab_cursor*); 5317 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5318 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5319 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5320 int (*xBegin)(sqlite3_vtab *pVTab); 5321 int (*xSync)(sqlite3_vtab *pVTab); 5322 int (*xCommit)(sqlite3_vtab *pVTab); 5323 int (*xRollback)(sqlite3_vtab *pVTab); 5324 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5325 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5326 void **ppArg); 5327 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5328 /* The methods above are in version 1 of the sqlite_module object. Those 5329 ** below are for version 2 and greater. */ 5330 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5331 int (*xRelease)(sqlite3_vtab *pVTab, int); 5332 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5333}; 5334 5335/* 5336** CAPI3REF: Virtual Table Indexing Information 5337** KEYWORDS: sqlite3_index_info 5338** 5339** The sqlite3_index_info structure and its substructures is used as part 5340** of the [virtual table] interface to 5341** pass information into and receive the reply from the [xBestIndex] 5342** method of a [virtual table module]. The fields under **Inputs** are the 5343** inputs to xBestIndex and are read-only. xBestIndex inserts its 5344** results into the **Outputs** fields. 5345** 5346** ^(The aConstraint[] array records WHERE clause constraints of the form: 5347** 5348** <blockquote>column OP expr</blockquote> 5349** 5350** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5351** stored in aConstraint[].op using one of the 5352** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5353** ^(The index of the column is stored in 5354** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5355** expr on the right-hand side can be evaluated (and thus the constraint 5356** is usable) and false if it cannot.)^ 5357** 5358** ^The optimizer automatically inverts terms of the form "expr OP column" 5359** and makes other simplifications to the WHERE clause in an attempt to 5360** get as many WHERE clause terms into the form shown above as possible. 5361** ^The aConstraint[] array only reports WHERE clause terms that are 5362** relevant to the particular virtual table being queried. 5363** 5364** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5365** ^Each term of aOrderBy records a column of the ORDER BY clause. 5366** 5367** The [xBestIndex] method must fill aConstraintUsage[] with information 5368** about what parameters to pass to xFilter. ^If argvIndex>0 then 5369** the right-hand side of the corresponding aConstraint[] is evaluated 5370** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5371** is true, then the constraint is assumed to be fully handled by the 5372** virtual table and is not checked again by SQLite.)^ 5373** 5374** ^The idxNum and idxPtr values are recorded and passed into the 5375** [xFilter] method. 5376** ^[sqlite3_free()] is used to free idxPtr if and only if 5377** needToFreeIdxPtr is true. 5378** 5379** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5380** the correct order to satisfy the ORDER BY clause so that no separate 5381** sorting step is required. 5382** 5383** ^The estimatedCost value is an estimate of the cost of a particular 5384** strategy. A cost of N indicates that the cost of the strategy is similar 5385** to a linear scan of an SQLite table with N rows. A cost of log(N) 5386** indicates that the expense of the operation is similar to that of a 5387** binary search on a unique indexed field of an SQLite table with N rows. 5388** 5389** ^The estimatedRows value is an estimate of the number of rows that 5390** will be returned by the strategy. 5391** 5392** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 5393** structure for SQLite version 3.8.2. If a virtual table extension is 5394** used with an SQLite version earlier than 3.8.2, the results of attempting 5395** to read or write the estimatedRows field are undefined (but are likely 5396** to included crashing the application). The estimatedRows field should 5397** therefore only be used if [sqlite3_libversion_number()] returns a 5398** value greater than or equal to 3008002. 5399*/ 5400struct sqlite3_index_info { 5401 /* Inputs */ 5402 int nConstraint; /* Number of entries in aConstraint */ 5403 struct sqlite3_index_constraint { 5404 int iColumn; /* Column on left-hand side of constraint */ 5405 unsigned char op; /* Constraint operator */ 5406 unsigned char usable; /* True if this constraint is usable */ 5407 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5408 } *aConstraint; /* Table of WHERE clause constraints */ 5409 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5410 struct sqlite3_index_orderby { 5411 int iColumn; /* Column number */ 5412 unsigned char desc; /* True for DESC. False for ASC. */ 5413 } *aOrderBy; /* The ORDER BY clause */ 5414 /* Outputs */ 5415 struct sqlite3_index_constraint_usage { 5416 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5417 unsigned char omit; /* Do not code a test for this constraint */ 5418 } *aConstraintUsage; 5419 int idxNum; /* Number used to identify the index */ 5420 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5421 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5422 int orderByConsumed; /* True if output is already ordered */ 5423 double estimatedCost; /* Estimated cost of using this index */ 5424 /* Fields below are only available in SQLite 3.8.2 and later */ 5425 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 5426}; 5427 5428/* 5429** CAPI3REF: Virtual Table Constraint Operator Codes 5430** 5431** These macros defined the allowed values for the 5432** [sqlite3_index_info].aConstraint[].op field. Each value represents 5433** an operator that is part of a constraint term in the wHERE clause of 5434** a query that uses a [virtual table]. 5435*/ 5436#define SQLITE_INDEX_CONSTRAINT_EQ 2 5437#define SQLITE_INDEX_CONSTRAINT_GT 4 5438#define SQLITE_INDEX_CONSTRAINT_LE 8 5439#define SQLITE_INDEX_CONSTRAINT_LT 16 5440#define SQLITE_INDEX_CONSTRAINT_GE 32 5441#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5442 5443/* 5444** CAPI3REF: Register A Virtual Table Implementation 5445** 5446** ^These routines are used to register a new [virtual table module] name. 5447** ^Module names must be registered before 5448** creating a new [virtual table] using the module and before using a 5449** preexisting [virtual table] for the module. 5450** 5451** ^The module name is registered on the [database connection] specified 5452** by the first parameter. ^The name of the module is given by the 5453** second parameter. ^The third parameter is a pointer to 5454** the implementation of the [virtual table module]. ^The fourth 5455** parameter is an arbitrary client data pointer that is passed through 5456** into the [xCreate] and [xConnect] methods of the virtual table module 5457** when a new virtual table is be being created or reinitialized. 5458** 5459** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5460** is a pointer to a destructor for the pClientData. ^SQLite will 5461** invoke the destructor function (if it is not NULL) when SQLite 5462** no longer needs the pClientData pointer. ^The destructor will also 5463** be invoked if the call to sqlite3_create_module_v2() fails. 5464** ^The sqlite3_create_module() 5465** interface is equivalent to sqlite3_create_module_v2() with a NULL 5466** destructor. 5467*/ 5468int sqlite3_create_module( 5469 sqlite3 *db, /* SQLite connection to register module with */ 5470 const char *zName, /* Name of the module */ 5471 const sqlite3_module *p, /* Methods for the module */ 5472 void *pClientData /* Client data for xCreate/xConnect */ 5473); 5474int sqlite3_create_module_v2( 5475 sqlite3 *db, /* SQLite connection to register module with */ 5476 const char *zName, /* Name of the module */ 5477 const sqlite3_module *p, /* Methods for the module */ 5478 void *pClientData, /* Client data for xCreate/xConnect */ 5479 void(*xDestroy)(void*) /* Module destructor function */ 5480); 5481 5482/* 5483** CAPI3REF: Virtual Table Instance Object 5484** KEYWORDS: sqlite3_vtab 5485** 5486** Every [virtual table module] implementation uses a subclass 5487** of this object to describe a particular instance 5488** of the [virtual table]. Each subclass will 5489** be tailored to the specific needs of the module implementation. 5490** The purpose of this superclass is to define certain fields that are 5491** common to all module implementations. 5492** 5493** ^Virtual tables methods can set an error message by assigning a 5494** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5495** take care that any prior string is freed by a call to [sqlite3_free()] 5496** prior to assigning a new string to zErrMsg. ^After the error message 5497** is delivered up to the client application, the string will be automatically 5498** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5499*/ 5500struct sqlite3_vtab { 5501 const sqlite3_module *pModule; /* The module for this virtual table */ 5502 int nRef; /* NO LONGER USED */ 5503 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5504 /* Virtual table implementations will typically add additional fields */ 5505}; 5506 5507/* 5508** CAPI3REF: Virtual Table Cursor Object 5509** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5510** 5511** Every [virtual table module] implementation uses a subclass of the 5512** following structure to describe cursors that point into the 5513** [virtual table] and are used 5514** to loop through the virtual table. Cursors are created using the 5515** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5516** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5517** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5518** of the module. Each module implementation will define 5519** the content of a cursor structure to suit its own needs. 5520** 5521** This superclass exists in order to define fields of the cursor that 5522** are common to all implementations. 5523*/ 5524struct sqlite3_vtab_cursor { 5525 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5526 /* Virtual table implementations will typically add additional fields */ 5527}; 5528 5529/* 5530** CAPI3REF: Declare The Schema Of A Virtual Table 5531** 5532** ^The [xCreate] and [xConnect] methods of a 5533** [virtual table module] call this interface 5534** to declare the format (the names and datatypes of the columns) of 5535** the virtual tables they implement. 5536*/ 5537int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5538 5539/* 5540** CAPI3REF: Overload A Function For A Virtual Table 5541** 5542** ^(Virtual tables can provide alternative implementations of functions 5543** using the [xFindFunction] method of the [virtual table module]. 5544** But global versions of those functions 5545** must exist in order to be overloaded.)^ 5546** 5547** ^(This API makes sure a global version of a function with a particular 5548** name and number of parameters exists. If no such function exists 5549** before this API is called, a new function is created.)^ ^The implementation 5550** of the new function always causes an exception to be thrown. So 5551** the new function is not good for anything by itself. Its only 5552** purpose is to be a placeholder function that can be overloaded 5553** by a [virtual table]. 5554*/ 5555int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5556 5557/* 5558** The interface to the virtual-table mechanism defined above (back up 5559** to a comment remarkably similar to this one) is currently considered 5560** to be experimental. The interface might change in incompatible ways. 5561** If this is a problem for you, do not use the interface at this time. 5562** 5563** When the virtual-table mechanism stabilizes, we will declare the 5564** interface fixed, support it indefinitely, and remove this comment. 5565*/ 5566 5567/* 5568** CAPI3REF: A Handle To An Open BLOB 5569** KEYWORDS: {BLOB handle} {BLOB handles} 5570** 5571** An instance of this object represents an open BLOB on which 5572** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5573** ^Objects of this type are created by [sqlite3_blob_open()] 5574** and destroyed by [sqlite3_blob_close()]. 5575** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5576** can be used to read or write small subsections of the BLOB. 5577** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5578*/ 5579typedef struct sqlite3_blob sqlite3_blob; 5580 5581/* 5582** CAPI3REF: Open A BLOB For Incremental I/O 5583** 5584** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5585** in row iRow, column zColumn, table zTable in database zDb; 5586** in other words, the same BLOB that would be selected by: 5587** 5588** <pre> 5589** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5590** </pre>)^ 5591** 5592** ^If the flags parameter is non-zero, then the BLOB is opened for read 5593** and write access. ^If it is zero, the BLOB is opened for read access. 5594** ^It is not possible to open a column that is part of an index or primary 5595** key for writing. ^If [foreign key constraints] are enabled, it is 5596** not possible to open a column that is part of a [child key] for writing. 5597** 5598** ^Note that the database name is not the filename that contains 5599** the database but rather the symbolic name of the database that 5600** appears after the AS keyword when the database is connected using [ATTACH]. 5601** ^For the main database file, the database name is "main". 5602** ^For TEMP tables, the database name is "temp". 5603** 5604** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5605** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5606** to be a null pointer.)^ 5607** ^This function sets the [database connection] error code and message 5608** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5609** functions. ^Note that the *ppBlob variable is always initialized in a 5610** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5611** regardless of the success or failure of this routine. 5612** 5613** ^(If the row that a BLOB handle points to is modified by an 5614** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5615** then the BLOB handle is marked as "expired". 5616** This is true if any column of the row is changed, even a column 5617** other than the one the BLOB handle is open on.)^ 5618** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5619** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5620** ^(Changes written into a BLOB prior to the BLOB expiring are not 5621** rolled back by the expiration of the BLOB. Such changes will eventually 5622** commit if the transaction continues to completion.)^ 5623** 5624** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5625** the opened blob. ^The size of a blob may not be changed by this 5626** interface. Use the [UPDATE] SQL command to change the size of a 5627** blob. 5628** 5629** ^The [sqlite3_blob_open()] interface will fail for a [WITHOUT ROWID] 5630** table. Incremental BLOB I/O is not possible on [WITHOUT ROWID] tables. 5631** 5632** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5633** and the built-in [zeroblob] SQL function can be used, if desired, 5634** to create an empty, zero-filled blob in which to read or write using 5635** this interface. 5636** 5637** To avoid a resource leak, every open [BLOB handle] should eventually 5638** be released by a call to [sqlite3_blob_close()]. 5639*/ 5640int sqlite3_blob_open( 5641 sqlite3*, 5642 const char *zDb, 5643 const char *zTable, 5644 const char *zColumn, 5645 sqlite3_int64 iRow, 5646 int flags, 5647 sqlite3_blob **ppBlob 5648); 5649 5650/* 5651** CAPI3REF: Move a BLOB Handle to a New Row 5652** 5653** ^This function is used to move an existing blob handle so that it points 5654** to a different row of the same database table. ^The new row is identified 5655** by the rowid value passed as the second argument. Only the row can be 5656** changed. ^The database, table and column on which the blob handle is open 5657** remain the same. Moving an existing blob handle to a new row can be 5658** faster than closing the existing handle and opening a new one. 5659** 5660** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5661** it must exist and there must be either a blob or text value stored in 5662** the nominated column.)^ ^If the new row is not present in the table, or if 5663** it does not contain a blob or text value, or if another error occurs, an 5664** SQLite error code is returned and the blob handle is considered aborted. 5665** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5666** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5667** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5668** always returns zero. 5669** 5670** ^This function sets the database handle error code and message. 5671*/ 5672SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5673 5674/* 5675** CAPI3REF: Close A BLOB Handle 5676** 5677** ^Closes an open [BLOB handle]. 5678** 5679** ^Closing a BLOB shall cause the current transaction to commit 5680** if there are no other BLOBs, no pending prepared statements, and the 5681** database connection is in [autocommit mode]. 5682** ^If any writes were made to the BLOB, they might be held in cache 5683** until the close operation if they will fit. 5684** 5685** ^(Closing the BLOB often forces the changes 5686** out to disk and so if any I/O errors occur, they will likely occur 5687** at the time when the BLOB is closed. Any errors that occur during 5688** closing are reported as a non-zero return value.)^ 5689** 5690** ^(The BLOB is closed unconditionally. Even if this routine returns 5691** an error code, the BLOB is still closed.)^ 5692** 5693** ^Calling this routine with a null pointer (such as would be returned 5694** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5695*/ 5696int sqlite3_blob_close(sqlite3_blob *); 5697 5698/* 5699** CAPI3REF: Return The Size Of An Open BLOB 5700** 5701** ^Returns the size in bytes of the BLOB accessible via the 5702** successfully opened [BLOB handle] in its only argument. ^The 5703** incremental blob I/O routines can only read or overwriting existing 5704** blob content; they cannot change the size of a blob. 5705** 5706** This routine only works on a [BLOB handle] which has been created 5707** by a prior successful call to [sqlite3_blob_open()] and which has not 5708** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5709** to this routine results in undefined and probably undesirable behavior. 5710*/ 5711int sqlite3_blob_bytes(sqlite3_blob *); 5712 5713/* 5714** CAPI3REF: Read Data From A BLOB Incrementally 5715** 5716** ^(This function is used to read data from an open [BLOB handle] into a 5717** caller-supplied buffer. N bytes of data are copied into buffer Z 5718** from the open BLOB, starting at offset iOffset.)^ 5719** 5720** ^If offset iOffset is less than N bytes from the end of the BLOB, 5721** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5722** less than zero, [SQLITE_ERROR] is returned and no data is read. 5723** ^The size of the blob (and hence the maximum value of N+iOffset) 5724** can be determined using the [sqlite3_blob_bytes()] interface. 5725** 5726** ^An attempt to read from an expired [BLOB handle] fails with an 5727** error code of [SQLITE_ABORT]. 5728** 5729** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5730** Otherwise, an [error code] or an [extended error code] is returned.)^ 5731** 5732** This routine only works on a [BLOB handle] which has been created 5733** by a prior successful call to [sqlite3_blob_open()] and which has not 5734** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5735** to this routine results in undefined and probably undesirable behavior. 5736** 5737** See also: [sqlite3_blob_write()]. 5738*/ 5739int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5740 5741/* 5742** CAPI3REF: Write Data Into A BLOB Incrementally 5743** 5744** ^This function is used to write data into an open [BLOB handle] from a 5745** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5746** into the open BLOB, starting at offset iOffset. 5747** 5748** ^If the [BLOB handle] passed as the first argument was not opened for 5749** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5750** this function returns [SQLITE_READONLY]. 5751** 5752** ^This function may only modify the contents of the BLOB; it is 5753** not possible to increase the size of a BLOB using this API. 5754** ^If offset iOffset is less than N bytes from the end of the BLOB, 5755** [SQLITE_ERROR] is returned and no data is written. ^If N is 5756** less than zero [SQLITE_ERROR] is returned and no data is written. 5757** The size of the BLOB (and hence the maximum value of N+iOffset) 5758** can be determined using the [sqlite3_blob_bytes()] interface. 5759** 5760** ^An attempt to write to an expired [BLOB handle] fails with an 5761** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5762** before the [BLOB handle] expired are not rolled back by the 5763** expiration of the handle, though of course those changes might 5764** have been overwritten by the statement that expired the BLOB handle 5765** or by other independent statements. 5766** 5767** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5768** Otherwise, an [error code] or an [extended error code] is returned.)^ 5769** 5770** This routine only works on a [BLOB handle] which has been created 5771** by a prior successful call to [sqlite3_blob_open()] and which has not 5772** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5773** to this routine results in undefined and probably undesirable behavior. 5774** 5775** See also: [sqlite3_blob_read()]. 5776*/ 5777int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5778 5779/* 5780** CAPI3REF: Virtual File System Objects 5781** 5782** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5783** that SQLite uses to interact 5784** with the underlying operating system. Most SQLite builds come with a 5785** single default VFS that is appropriate for the host computer. 5786** New VFSes can be registered and existing VFSes can be unregistered. 5787** The following interfaces are provided. 5788** 5789** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5790** ^Names are case sensitive. 5791** ^Names are zero-terminated UTF-8 strings. 5792** ^If there is no match, a NULL pointer is returned. 5793** ^If zVfsName is NULL then the default VFS is returned. 5794** 5795** ^New VFSes are registered with sqlite3_vfs_register(). 5796** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5797** ^The same VFS can be registered multiple times without injury. 5798** ^To make an existing VFS into the default VFS, register it again 5799** with the makeDflt flag set. If two different VFSes with the 5800** same name are registered, the behavior is undefined. If a 5801** VFS is registered with a name that is NULL or an empty string, 5802** then the behavior is undefined. 5803** 5804** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5805** ^(If the default VFS is unregistered, another VFS is chosen as 5806** the default. The choice for the new VFS is arbitrary.)^ 5807*/ 5808sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5809int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5810int sqlite3_vfs_unregister(sqlite3_vfs*); 5811 5812/* 5813** CAPI3REF: Mutexes 5814** 5815** The SQLite core uses these routines for thread 5816** synchronization. Though they are intended for internal 5817** use by SQLite, code that links against SQLite is 5818** permitted to use any of these routines. 5819** 5820** The SQLite source code contains multiple implementations 5821** of these mutex routines. An appropriate implementation 5822** is selected automatically at compile-time. ^(The following 5823** implementations are available in the SQLite core: 5824** 5825** <ul> 5826** <li> SQLITE_MUTEX_PTHREADS 5827** <li> SQLITE_MUTEX_W32 5828** <li> SQLITE_MUTEX_NOOP 5829** </ul>)^ 5830** 5831** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5832** that does no real locking and is appropriate for use in 5833** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and 5834** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 5835** and Windows. 5836** 5837** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5838** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5839** implementation is included with the library. In this case the 5840** application must supply a custom mutex implementation using the 5841** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5842** before calling sqlite3_initialize() or any other public sqlite3_ 5843** function that calls sqlite3_initialize().)^ 5844** 5845** ^The sqlite3_mutex_alloc() routine allocates a new 5846** mutex and returns a pointer to it. ^If it returns NULL 5847** that means that a mutex could not be allocated. ^SQLite 5848** will unwind its stack and return an error. ^(The argument 5849** to sqlite3_mutex_alloc() is one of these integer constants: 5850** 5851** <ul> 5852** <li> SQLITE_MUTEX_FAST 5853** <li> SQLITE_MUTEX_RECURSIVE 5854** <li> SQLITE_MUTEX_STATIC_MASTER 5855** <li> SQLITE_MUTEX_STATIC_MEM 5856** <li> SQLITE_MUTEX_STATIC_MEM2 5857** <li> SQLITE_MUTEX_STATIC_PRNG 5858** <li> SQLITE_MUTEX_STATIC_LRU 5859** <li> SQLITE_MUTEX_STATIC_LRU2 5860** </ul>)^ 5861** 5862** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5863** cause sqlite3_mutex_alloc() to create 5864** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5865** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5866** The mutex implementation does not need to make a distinction 5867** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5868** not want to. ^SQLite will only request a recursive mutex in 5869** cases where it really needs one. ^If a faster non-recursive mutex 5870** implementation is available on the host platform, the mutex subsystem 5871** might return such a mutex in response to SQLITE_MUTEX_FAST. 5872** 5873** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5874** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5875** a pointer to a static preexisting mutex. ^Six static mutexes are 5876** used by the current version of SQLite. Future versions of SQLite 5877** may add additional static mutexes. Static mutexes are for internal 5878** use by SQLite only. Applications that use SQLite mutexes should 5879** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5880** SQLITE_MUTEX_RECURSIVE. 5881** 5882** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5883** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5884** returns a different mutex on every call. ^But for the static 5885** mutex types, the same mutex is returned on every call that has 5886** the same type number. 5887** 5888** ^The sqlite3_mutex_free() routine deallocates a previously 5889** allocated dynamic mutex. ^SQLite is careful to deallocate every 5890** dynamic mutex that it allocates. The dynamic mutexes must not be in 5891** use when they are deallocated. Attempting to deallocate a static 5892** mutex results in undefined behavior. ^SQLite never deallocates 5893** a static mutex. 5894** 5895** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5896** to enter a mutex. ^If another thread is already within the mutex, 5897** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5898** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5899** upon successful entry. ^(Mutexes created using 5900** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5901** In such cases the, 5902** mutex must be exited an equal number of times before another thread 5903** can enter.)^ ^(If the same thread tries to enter any other 5904** kind of mutex more than once, the behavior is undefined. 5905** SQLite will never exhibit 5906** such behavior in its own use of mutexes.)^ 5907** 5908** ^(Some systems (for example, Windows 95) do not support the operation 5909** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5910** will always return SQLITE_BUSY. The SQLite core only ever uses 5911** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5912** 5913** ^The sqlite3_mutex_leave() routine exits a mutex that was 5914** previously entered by the same thread. ^(The behavior 5915** is undefined if the mutex is not currently entered by the 5916** calling thread or is not currently allocated. SQLite will 5917** never do either.)^ 5918** 5919** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5920** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5921** behave as no-ops. 5922** 5923** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5924*/ 5925sqlite3_mutex *sqlite3_mutex_alloc(int); 5926void sqlite3_mutex_free(sqlite3_mutex*); 5927void sqlite3_mutex_enter(sqlite3_mutex*); 5928int sqlite3_mutex_try(sqlite3_mutex*); 5929void sqlite3_mutex_leave(sqlite3_mutex*); 5930 5931/* 5932** CAPI3REF: Mutex Methods Object 5933** 5934** An instance of this structure defines the low-level routines 5935** used to allocate and use mutexes. 5936** 5937** Usually, the default mutex implementations provided by SQLite are 5938** sufficient, however the user has the option of substituting a custom 5939** implementation for specialized deployments or systems for which SQLite 5940** does not provide a suitable implementation. In this case, the user 5941** creates and populates an instance of this structure to pass 5942** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5943** Additionally, an instance of this structure can be used as an 5944** output variable when querying the system for the current mutex 5945** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5946** 5947** ^The xMutexInit method defined by this structure is invoked as 5948** part of system initialization by the sqlite3_initialize() function. 5949** ^The xMutexInit routine is called by SQLite exactly once for each 5950** effective call to [sqlite3_initialize()]. 5951** 5952** ^The xMutexEnd method defined by this structure is invoked as 5953** part of system shutdown by the sqlite3_shutdown() function. The 5954** implementation of this method is expected to release all outstanding 5955** resources obtained by the mutex methods implementation, especially 5956** those obtained by the xMutexInit method. ^The xMutexEnd() 5957** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5958** 5959** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5960** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5961** xMutexNotheld) implement the following interfaces (respectively): 5962** 5963** <ul> 5964** <li> [sqlite3_mutex_alloc()] </li> 5965** <li> [sqlite3_mutex_free()] </li> 5966** <li> [sqlite3_mutex_enter()] </li> 5967** <li> [sqlite3_mutex_try()] </li> 5968** <li> [sqlite3_mutex_leave()] </li> 5969** <li> [sqlite3_mutex_held()] </li> 5970** <li> [sqlite3_mutex_notheld()] </li> 5971** </ul>)^ 5972** 5973** The only difference is that the public sqlite3_XXX functions enumerated 5974** above silently ignore any invocations that pass a NULL pointer instead 5975** of a valid mutex handle. The implementations of the methods defined 5976** by this structure are not required to handle this case, the results 5977** of passing a NULL pointer instead of a valid mutex handle are undefined 5978** (i.e. it is acceptable to provide an implementation that segfaults if 5979** it is passed a NULL pointer). 5980** 5981** The xMutexInit() method must be threadsafe. ^It must be harmless to 5982** invoke xMutexInit() multiple times within the same process and without 5983** intervening calls to xMutexEnd(). Second and subsequent calls to 5984** xMutexInit() must be no-ops. 5985** 5986** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5987** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5988** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5989** memory allocation for a fast or recursive mutex. 5990** 5991** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5992** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5993** If xMutexInit fails in any way, it is expected to clean up after itself 5994** prior to returning. 5995*/ 5996typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5997struct sqlite3_mutex_methods { 5998 int (*xMutexInit)(void); 5999 int (*xMutexEnd)(void); 6000 sqlite3_mutex *(*xMutexAlloc)(int); 6001 void (*xMutexFree)(sqlite3_mutex *); 6002 void (*xMutexEnter)(sqlite3_mutex *); 6003 int (*xMutexTry)(sqlite3_mutex *); 6004 void (*xMutexLeave)(sqlite3_mutex *); 6005 int (*xMutexHeld)(sqlite3_mutex *); 6006 int (*xMutexNotheld)(sqlite3_mutex *); 6007}; 6008 6009/* 6010** CAPI3REF: Mutex Verification Routines 6011** 6012** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6013** are intended for use inside assert() statements. ^The SQLite core 6014** never uses these routines except inside an assert() and applications 6015** are advised to follow the lead of the core. ^The SQLite core only 6016** provides implementations for these routines when it is compiled 6017** with the SQLITE_DEBUG flag. ^External mutex implementations 6018** are only required to provide these routines if SQLITE_DEBUG is 6019** defined and if NDEBUG is not defined. 6020** 6021** ^These routines should return true if the mutex in their argument 6022** is held or not held, respectively, by the calling thread. 6023** 6024** ^The implementation is not required to provide versions of these 6025** routines that actually work. If the implementation does not provide working 6026** versions of these routines, it should at least provide stubs that always 6027** return true so that one does not get spurious assertion failures. 6028** 6029** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 6030** the routine should return 1. This seems counter-intuitive since 6031** clearly the mutex cannot be held if it does not exist. But 6032** the reason the mutex does not exist is because the build is not 6033** using mutexes. And we do not want the assert() containing the 6034** call to sqlite3_mutex_held() to fail, so a non-zero return is 6035** the appropriate thing to do. ^The sqlite3_mutex_notheld() 6036** interface should also return 1 when given a NULL pointer. 6037*/ 6038#ifndef NDEBUG 6039int sqlite3_mutex_held(sqlite3_mutex*); 6040int sqlite3_mutex_notheld(sqlite3_mutex*); 6041#endif 6042 6043/* 6044** CAPI3REF: Mutex Types 6045** 6046** The [sqlite3_mutex_alloc()] interface takes a single argument 6047** which is one of these integer constants. 6048** 6049** The set of static mutexes may change from one SQLite release to the 6050** next. Applications that override the built-in mutex logic must be 6051** prepared to accommodate additional static mutexes. 6052*/ 6053#define SQLITE_MUTEX_FAST 0 6054#define SQLITE_MUTEX_RECURSIVE 1 6055#define SQLITE_MUTEX_STATIC_MASTER 2 6056#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6057#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6058#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6059#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 6060#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6061#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6062#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6063 6064/* 6065** CAPI3REF: Retrieve the mutex for a database connection 6066** 6067** ^This interface returns a pointer the [sqlite3_mutex] object that 6068** serializes access to the [database connection] given in the argument 6069** when the [threading mode] is Serialized. 6070** ^If the [threading mode] is Single-thread or Multi-thread then this 6071** routine returns a NULL pointer. 6072*/ 6073sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6074 6075/* 6076** CAPI3REF: Low-Level Control Of Database Files 6077** 6078** ^The [sqlite3_file_control()] interface makes a direct call to the 6079** xFileControl method for the [sqlite3_io_methods] object associated 6080** with a particular database identified by the second argument. ^The 6081** name of the database is "main" for the main database or "temp" for the 6082** TEMP database, or the name that appears after the AS keyword for 6083** databases that are added using the [ATTACH] SQL command. 6084** ^A NULL pointer can be used in place of "main" to refer to the 6085** main database file. 6086** ^The third and fourth parameters to this routine 6087** are passed directly through to the second and third parameters of 6088** the xFileControl method. ^The return value of the xFileControl 6089** method becomes the return value of this routine. 6090** 6091** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6092** a pointer to the underlying [sqlite3_file] object to be written into 6093** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6094** case is a short-circuit path which does not actually invoke the 6095** underlying sqlite3_io_methods.xFileControl method. 6096** 6097** ^If the second parameter (zDbName) does not match the name of any 6098** open database file, then SQLITE_ERROR is returned. ^This error 6099** code is not remembered and will not be recalled by [sqlite3_errcode()] 6100** or [sqlite3_errmsg()]. The underlying xFileControl method might 6101** also return SQLITE_ERROR. There is no way to distinguish between 6102** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6103** xFileControl method. 6104** 6105** See also: [SQLITE_FCNTL_LOCKSTATE] 6106*/ 6107int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6108 6109/* 6110** CAPI3REF: Testing Interface 6111** 6112** ^The sqlite3_test_control() interface is used to read out internal 6113** state of SQLite and to inject faults into SQLite for testing 6114** purposes. ^The first parameter is an operation code that determines 6115** the number, meaning, and operation of all subsequent parameters. 6116** 6117** This interface is not for use by applications. It exists solely 6118** for verifying the correct operation of the SQLite library. Depending 6119** on how the SQLite library is compiled, this interface might not exist. 6120** 6121** The details of the operation codes, their meanings, the parameters 6122** they take, and what they do are all subject to change without notice. 6123** Unlike most of the SQLite API, this function is not guaranteed to 6124** operate consistently from one release to the next. 6125*/ 6126int sqlite3_test_control(int op, ...); 6127 6128/* 6129** CAPI3REF: Testing Interface Operation Codes 6130** 6131** These constants are the valid operation code parameters used 6132** as the first argument to [sqlite3_test_control()]. 6133** 6134** These parameters and their meanings are subject to change 6135** without notice. These values are for testing purposes only. 6136** Applications should not use any of these parameters or the 6137** [sqlite3_test_control()] interface. 6138*/ 6139#define SQLITE_TESTCTRL_FIRST 5 6140#define SQLITE_TESTCTRL_PRNG_SAVE 5 6141#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6142#define SQLITE_TESTCTRL_PRNG_RESET 7 6143#define SQLITE_TESTCTRL_BITVEC_TEST 8 6144#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6145#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6146#define SQLITE_TESTCTRL_PENDING_BYTE 11 6147#define SQLITE_TESTCTRL_ASSERT 12 6148#define SQLITE_TESTCTRL_ALWAYS 13 6149#define SQLITE_TESTCTRL_RESERVE 14 6150#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6151#define SQLITE_TESTCTRL_ISKEYWORD 16 6152#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6153#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6154#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 6155#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6156#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6157#define SQLITE_TESTCTRL_BYTEORDER 22 6158#define SQLITE_TESTCTRL_LAST 22 6159 6160/* 6161** CAPI3REF: SQLite Runtime Status 6162** 6163** ^This interface is used to retrieve runtime status information 6164** about the performance of SQLite, and optionally to reset various 6165** highwater marks. ^The first argument is an integer code for 6166** the specific parameter to measure. ^(Recognized integer codes 6167** are of the form [status parameters | SQLITE_STATUS_...].)^ 6168** ^The current value of the parameter is returned into *pCurrent. 6169** ^The highest recorded value is returned in *pHighwater. ^If the 6170** resetFlag is true, then the highest record value is reset after 6171** *pHighwater is written. ^(Some parameters do not record the highest 6172** value. For those parameters 6173** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6174** ^(Other parameters record only the highwater mark and not the current 6175** value. For these latter parameters nothing is written into *pCurrent.)^ 6176** 6177** ^The sqlite3_status() routine returns SQLITE_OK on success and a 6178** non-zero [error code] on failure. 6179** 6180** This routine is threadsafe but is not atomic. This routine can be 6181** called while other threads are running the same or different SQLite 6182** interfaces. However the values returned in *pCurrent and 6183** *pHighwater reflect the status of SQLite at different points in time 6184** and it is possible that another thread might change the parameter 6185** in between the times when *pCurrent and *pHighwater are written. 6186** 6187** See also: [sqlite3_db_status()] 6188*/ 6189int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6190 6191 6192/* 6193** CAPI3REF: Status Parameters 6194** KEYWORDS: {status parameters} 6195** 6196** These integer constants designate various run-time status parameters 6197** that can be returned by [sqlite3_status()]. 6198** 6199** <dl> 6200** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6201** <dd>This parameter is the current amount of memory checked out 6202** using [sqlite3_malloc()], either directly or indirectly. The 6203** figure includes calls made to [sqlite3_malloc()] by the application 6204** and internal memory usage by the SQLite library. Scratch memory 6205** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6206** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6207** this parameter. The amount returned is the sum of the allocation 6208** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6209** 6210** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6211** <dd>This parameter records the largest memory allocation request 6212** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6213** internal equivalents). Only the value returned in the 6214** *pHighwater parameter to [sqlite3_status()] is of interest. 6215** The value written into the *pCurrent parameter is undefined.</dd>)^ 6216** 6217** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6218** <dd>This parameter records the number of separate memory allocations 6219** currently checked out.</dd>)^ 6220** 6221** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6222** <dd>This parameter returns the number of pages used out of the 6223** [pagecache memory allocator] that was configured using 6224** [SQLITE_CONFIG_PAGECACHE]. The 6225** value returned is in pages, not in bytes.</dd>)^ 6226** 6227** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6228** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6229** <dd>This parameter returns the number of bytes of page cache 6230** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6231** buffer and where forced to overflow to [sqlite3_malloc()]. The 6232** returned value includes allocations that overflowed because they 6233** where too large (they were larger than the "sz" parameter to 6234** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6235** no space was left in the page cache.</dd>)^ 6236** 6237** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6238** <dd>This parameter records the largest memory allocation request 6239** handed to [pagecache memory allocator]. Only the value returned in the 6240** *pHighwater parameter to [sqlite3_status()] is of interest. 6241** The value written into the *pCurrent parameter is undefined.</dd>)^ 6242** 6243** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6244** <dd>This parameter returns the number of allocations used out of the 6245** [scratch memory allocator] configured using 6246** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6247** in bytes. Since a single thread may only have one scratch allocation 6248** outstanding at time, this parameter also reports the number of threads 6249** using scratch memory at the same time.</dd>)^ 6250** 6251** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6252** <dd>This parameter returns the number of bytes of scratch memory 6253** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6254** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6255** returned include overflows because the requested allocation was too 6256** larger (that is, because the requested allocation was larger than the 6257** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6258** slots were available. 6259** </dd>)^ 6260** 6261** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6262** <dd>This parameter records the largest memory allocation request 6263** handed to [scratch memory allocator]. Only the value returned in the 6264** *pHighwater parameter to [sqlite3_status()] is of interest. 6265** The value written into the *pCurrent parameter is undefined.</dd>)^ 6266** 6267** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6268** <dd>This parameter records the deepest parser stack. It is only 6269** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6270** </dl> 6271** 6272** New status parameters may be added from time to time. 6273*/ 6274#define SQLITE_STATUS_MEMORY_USED 0 6275#define SQLITE_STATUS_PAGECACHE_USED 1 6276#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6277#define SQLITE_STATUS_SCRATCH_USED 3 6278#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6279#define SQLITE_STATUS_MALLOC_SIZE 5 6280#define SQLITE_STATUS_PARSER_STACK 6 6281#define SQLITE_STATUS_PAGECACHE_SIZE 7 6282#define SQLITE_STATUS_SCRATCH_SIZE 8 6283#define SQLITE_STATUS_MALLOC_COUNT 9 6284 6285/* 6286** CAPI3REF: Database Connection Status 6287** 6288** ^This interface is used to retrieve runtime status information 6289** about a single [database connection]. ^The first argument is the 6290** database connection object to be interrogated. ^The second argument 6291** is an integer constant, taken from the set of 6292** [SQLITE_DBSTATUS options], that 6293** determines the parameter to interrogate. The set of 6294** [SQLITE_DBSTATUS options] is likely 6295** to grow in future releases of SQLite. 6296** 6297** ^The current value of the requested parameter is written into *pCur 6298** and the highest instantaneous value is written into *pHiwtr. ^If 6299** the resetFlg is true, then the highest instantaneous value is 6300** reset back down to the current value. 6301** 6302** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6303** non-zero [error code] on failure. 6304** 6305** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6306*/ 6307int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6308 6309/* 6310** CAPI3REF: Status Parameters for database connections 6311** KEYWORDS: {SQLITE_DBSTATUS options} 6312** 6313** These constants are the available integer "verbs" that can be passed as 6314** the second argument to the [sqlite3_db_status()] interface. 6315** 6316** New verbs may be added in future releases of SQLite. Existing verbs 6317** might be discontinued. Applications should check the return code from 6318** [sqlite3_db_status()] to make sure that the call worked. 6319** The [sqlite3_db_status()] interface will return a non-zero error code 6320** if a discontinued or unsupported verb is invoked. 6321** 6322** <dl> 6323** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6324** <dd>This parameter returns the number of lookaside memory slots currently 6325** checked out.</dd>)^ 6326** 6327** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6328** <dd>This parameter returns the number malloc attempts that were 6329** satisfied using lookaside memory. Only the high-water value is meaningful; 6330** the current value is always zero.)^ 6331** 6332** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6333** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6334** <dd>This parameter returns the number malloc attempts that might have 6335** been satisfied using lookaside memory but failed due to the amount of 6336** memory requested being larger than the lookaside slot size. 6337** Only the high-water value is meaningful; 6338** the current value is always zero.)^ 6339** 6340** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6341** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6342** <dd>This parameter returns the number malloc attempts that might have 6343** been satisfied using lookaside memory but failed due to all lookaside 6344** memory already being in use. 6345** Only the high-water value is meaningful; 6346** the current value is always zero.)^ 6347** 6348** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6349** <dd>This parameter returns the approximate number of of bytes of heap 6350** memory used by all pager caches associated with the database connection.)^ 6351** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6352** 6353** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6354** <dd>This parameter returns the approximate number of of bytes of heap 6355** memory used to store the schema for all databases associated 6356** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6357** ^The full amount of memory used by the schemas is reported, even if the 6358** schema memory is shared with other database connections due to 6359** [shared cache mode] being enabled. 6360** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6361** 6362** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6363** <dd>This parameter returns the approximate number of of bytes of heap 6364** and lookaside memory used by all prepared statements associated with 6365** the database connection.)^ 6366** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6367** </dd> 6368** 6369** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6370** <dd>This parameter returns the number of pager cache hits that have 6371** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6372** is always 0. 6373** </dd> 6374** 6375** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6376** <dd>This parameter returns the number of pager cache misses that have 6377** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6378** is always 0. 6379** </dd> 6380** 6381** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6382** <dd>This parameter returns the number of dirty cache entries that have 6383** been written to disk. Specifically, the number of pages written to the 6384** wal file in wal mode databases, or the number of pages written to the 6385** database file in rollback mode databases. Any pages written as part of 6386** transaction rollback or database recovery operations are not included. 6387** If an IO or other error occurs while writing a page to disk, the effect 6388** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6389** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6390** </dd> 6391** 6392** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 6393** <dd>This parameter returns zero for the current value if and only if 6394** all foreign key constraints (deferred or immediate) have been 6395** resolved.)^ ^The highwater mark is always 0. 6396** </dd> 6397** </dl> 6398*/ 6399#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6400#define SQLITE_DBSTATUS_CACHE_USED 1 6401#define SQLITE_DBSTATUS_SCHEMA_USED 2 6402#define SQLITE_DBSTATUS_STMT_USED 3 6403#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6404#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6405#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6406#define SQLITE_DBSTATUS_CACHE_HIT 7 6407#define SQLITE_DBSTATUS_CACHE_MISS 8 6408#define SQLITE_DBSTATUS_CACHE_WRITE 9 6409#define SQLITE_DBSTATUS_DEFERRED_FKS 10 6410#define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */ 6411 6412 6413/* 6414** CAPI3REF: Prepared Statement Status 6415** 6416** ^(Each prepared statement maintains various 6417** [SQLITE_STMTSTATUS counters] that measure the number 6418** of times it has performed specific operations.)^ These counters can 6419** be used to monitor the performance characteristics of the prepared 6420** statements. For example, if the number of table steps greatly exceeds 6421** the number of table searches or result rows, that would tend to indicate 6422** that the prepared statement is using a full table scan rather than 6423** an index. 6424** 6425** ^(This interface is used to retrieve and reset counter values from 6426** a [prepared statement]. The first argument is the prepared statement 6427** object to be interrogated. The second argument 6428** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6429** to be interrogated.)^ 6430** ^The current value of the requested counter is returned. 6431** ^If the resetFlg is true, then the counter is reset to zero after this 6432** interface call returns. 6433** 6434** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6435*/ 6436int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6437 6438/* 6439** CAPI3REF: Status Parameters for prepared statements 6440** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6441** 6442** These preprocessor macros define integer codes that name counter 6443** values associated with the [sqlite3_stmt_status()] interface. 6444** The meanings of the various counters are as follows: 6445** 6446** <dl> 6447** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6448** <dd>^This is the number of times that SQLite has stepped forward in 6449** a table as part of a full table scan. Large numbers for this counter 6450** may indicate opportunities for performance improvement through 6451** careful use of indices.</dd> 6452** 6453** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6454** <dd>^This is the number of sort operations that have occurred. 6455** A non-zero value in this counter may indicate an opportunity to 6456** improvement performance through careful use of indices.</dd> 6457** 6458** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6459** <dd>^This is the number of rows inserted into transient indices that 6460** were created automatically in order to help joins run faster. 6461** A non-zero value in this counter may indicate an opportunity to 6462** improvement performance by adding permanent indices that do not 6463** need to be reinitialized each time the statement is run.</dd> 6464** 6465** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 6466** <dd>^This is the number of virtual machine operations executed 6467** by the prepared statement if that number is less than or equal 6468** to 2147483647. The number of virtual machine operations can be 6469** used as a proxy for the total work done by the prepared statement. 6470** If the number of virtual machine operations exceeds 2147483647 6471** then the value returned by this statement status code is undefined. 6472** </dd> 6473** </dl> 6474*/ 6475#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6476#define SQLITE_STMTSTATUS_SORT 2 6477#define SQLITE_STMTSTATUS_AUTOINDEX 3 6478#define SQLITE_STMTSTATUS_VM_STEP 4 6479 6480/* 6481** CAPI3REF: Custom Page Cache Object 6482** 6483** The sqlite3_pcache type is opaque. It is implemented by 6484** the pluggable module. The SQLite core has no knowledge of 6485** its size or internal structure and never deals with the 6486** sqlite3_pcache object except by holding and passing pointers 6487** to the object. 6488** 6489** See [sqlite3_pcache_methods2] for additional information. 6490*/ 6491typedef struct sqlite3_pcache sqlite3_pcache; 6492 6493/* 6494** CAPI3REF: Custom Page Cache Object 6495** 6496** The sqlite3_pcache_page object represents a single page in the 6497** page cache. The page cache will allocate instances of this 6498** object. Various methods of the page cache use pointers to instances 6499** of this object as parameters or as their return value. 6500** 6501** See [sqlite3_pcache_methods2] for additional information. 6502*/ 6503typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6504struct sqlite3_pcache_page { 6505 void *pBuf; /* The content of the page */ 6506 void *pExtra; /* Extra information associated with the page */ 6507}; 6508 6509/* 6510** CAPI3REF: Application Defined Page Cache. 6511** KEYWORDS: {page cache} 6512** 6513** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6514** register an alternative page cache implementation by passing in an 6515** instance of the sqlite3_pcache_methods2 structure.)^ 6516** In many applications, most of the heap memory allocated by 6517** SQLite is used for the page cache. 6518** By implementing a 6519** custom page cache using this API, an application can better control 6520** the amount of memory consumed by SQLite, the way in which 6521** that memory is allocated and released, and the policies used to 6522** determine exactly which parts of a database file are cached and for 6523** how long. 6524** 6525** The alternative page cache mechanism is an 6526** extreme measure that is only needed by the most demanding applications. 6527** The built-in page cache is recommended for most uses. 6528** 6529** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6530** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6531** the application may discard the parameter after the call to 6532** [sqlite3_config()] returns.)^ 6533** 6534** [[the xInit() page cache method]] 6535** ^(The xInit() method is called once for each effective 6536** call to [sqlite3_initialize()])^ 6537** (usually only once during the lifetime of the process). ^(The xInit() 6538** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6539** The intent of the xInit() method is to set up global data structures 6540** required by the custom page cache implementation. 6541** ^(If the xInit() method is NULL, then the 6542** built-in default page cache is used instead of the application defined 6543** page cache.)^ 6544** 6545** [[the xShutdown() page cache method]] 6546** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6547** It can be used to clean up 6548** any outstanding resources before process shutdown, if required. 6549** ^The xShutdown() method may be NULL. 6550** 6551** ^SQLite automatically serializes calls to the xInit method, 6552** so the xInit method need not be threadsafe. ^The 6553** xShutdown method is only called from [sqlite3_shutdown()] so it does 6554** not need to be threadsafe either. All other methods must be threadsafe 6555** in multithreaded applications. 6556** 6557** ^SQLite will never invoke xInit() more than once without an intervening 6558** call to xShutdown(). 6559** 6560** [[the xCreate() page cache methods]] 6561** ^SQLite invokes the xCreate() method to construct a new cache instance. 6562** SQLite will typically create one cache instance for each open database file, 6563** though this is not guaranteed. ^The 6564** first parameter, szPage, is the size in bytes of the pages that must 6565** be allocated by the cache. ^szPage will always a power of two. ^The 6566** second parameter szExtra is a number of bytes of extra storage 6567** associated with each page cache entry. ^The szExtra parameter will 6568** a number less than 250. SQLite will use the 6569** extra szExtra bytes on each page to store metadata about the underlying 6570** database page on disk. The value passed into szExtra depends 6571** on the SQLite version, the target platform, and how SQLite was compiled. 6572** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6573** created will be used to cache database pages of a file stored on disk, or 6574** false if it is used for an in-memory database. The cache implementation 6575** does not have to do anything special based with the value of bPurgeable; 6576** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6577** never invoke xUnpin() except to deliberately delete a page. 6578** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6579** false will always have the "discard" flag set to true. 6580** ^Hence, a cache created with bPurgeable false will 6581** never contain any unpinned pages. 6582** 6583** [[the xCachesize() page cache method]] 6584** ^(The xCachesize() method may be called at any time by SQLite to set the 6585** suggested maximum cache-size (number of pages stored by) the cache 6586** instance passed as the first argument. This is the value configured using 6587** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6588** parameter, the implementation is not required to do anything with this 6589** value; it is advisory only. 6590** 6591** [[the xPagecount() page cache methods]] 6592** The xPagecount() method must return the number of pages currently 6593** stored in the cache, both pinned and unpinned. 6594** 6595** [[the xFetch() page cache methods]] 6596** The xFetch() method locates a page in the cache and returns a pointer to 6597** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6598** The pBuf element of the returned sqlite3_pcache_page object will be a 6599** pointer to a buffer of szPage bytes used to store the content of a 6600** single database page. The pExtra element of sqlite3_pcache_page will be 6601** a pointer to the szExtra bytes of extra storage that SQLite has requested 6602** for each entry in the page cache. 6603** 6604** The page to be fetched is determined by the key. ^The minimum key value 6605** is 1. After it has been retrieved using xFetch, the page is considered 6606** to be "pinned". 6607** 6608** If the requested page is already in the page cache, then the page cache 6609** implementation must return a pointer to the page buffer with its content 6610** intact. If the requested page is not already in the cache, then the 6611** cache implementation should use the value of the createFlag 6612** parameter to help it determined what action to take: 6613** 6614** <table border=1 width=85% align=center> 6615** <tr><th> createFlag <th> Behavior when page is not already in cache 6616** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6617** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6618** Otherwise return NULL. 6619** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6620** NULL if allocating a new page is effectively impossible. 6621** </table> 6622** 6623** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6624** will only use a createFlag of 2 after a prior call with a createFlag of 1 6625** failed.)^ In between the to xFetch() calls, SQLite may 6626** attempt to unpin one or more cache pages by spilling the content of 6627** pinned pages to disk and synching the operating system disk cache. 6628** 6629** [[the xUnpin() page cache method]] 6630** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6631** as its second argument. If the third parameter, discard, is non-zero, 6632** then the page must be evicted from the cache. 6633** ^If the discard parameter is 6634** zero, then the page may be discarded or retained at the discretion of 6635** page cache implementation. ^The page cache implementation 6636** may choose to evict unpinned pages at any time. 6637** 6638** The cache must not perform any reference counting. A single 6639** call to xUnpin() unpins the page regardless of the number of prior calls 6640** to xFetch(). 6641** 6642** [[the xRekey() page cache methods]] 6643** The xRekey() method is used to change the key value associated with the 6644** page passed as the second argument. If the cache 6645** previously contains an entry associated with newKey, it must be 6646** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6647** to be pinned. 6648** 6649** When SQLite calls the xTruncate() method, the cache must discard all 6650** existing cache entries with page numbers (keys) greater than or equal 6651** to the value of the iLimit parameter passed to xTruncate(). If any 6652** of these pages are pinned, they are implicitly unpinned, meaning that 6653** they can be safely discarded. 6654** 6655** [[the xDestroy() page cache method]] 6656** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6657** All resources associated with the specified cache should be freed. ^After 6658** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6659** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6660** functions. 6661** 6662** [[the xShrink() page cache method]] 6663** ^SQLite invokes the xShrink() method when it wants the page cache to 6664** free up as much of heap memory as possible. The page cache implementation 6665** is not obligated to free any memory, but well-behaved implementations should 6666** do their best. 6667*/ 6668typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6669struct sqlite3_pcache_methods2 { 6670 int iVersion; 6671 void *pArg; 6672 int (*xInit)(void*); 6673 void (*xShutdown)(void*); 6674 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6675 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6676 int (*xPagecount)(sqlite3_pcache*); 6677 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6678 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6679 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6680 unsigned oldKey, unsigned newKey); 6681 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6682 void (*xDestroy)(sqlite3_pcache*); 6683 void (*xShrink)(sqlite3_pcache*); 6684}; 6685 6686/* 6687** This is the obsolete pcache_methods object that has now been replaced 6688** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6689** retained in the header file for backwards compatibility only. 6690*/ 6691typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6692struct sqlite3_pcache_methods { 6693 void *pArg; 6694 int (*xInit)(void*); 6695 void (*xShutdown)(void*); 6696 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6697 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6698 int (*xPagecount)(sqlite3_pcache*); 6699 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6700 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6701 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6702 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6703 void (*xDestroy)(sqlite3_pcache*); 6704}; 6705 6706 6707/* 6708** CAPI3REF: Online Backup Object 6709** 6710** The sqlite3_backup object records state information about an ongoing 6711** online backup operation. ^The sqlite3_backup object is created by 6712** a call to [sqlite3_backup_init()] and is destroyed by a call to 6713** [sqlite3_backup_finish()]. 6714** 6715** See Also: [Using the SQLite Online Backup API] 6716*/ 6717typedef struct sqlite3_backup sqlite3_backup; 6718 6719/* 6720** CAPI3REF: Online Backup API. 6721** 6722** The backup API copies the content of one database into another. 6723** It is useful either for creating backups of databases or 6724** for copying in-memory databases to or from persistent files. 6725** 6726** See Also: [Using the SQLite Online Backup API] 6727** 6728** ^SQLite holds a write transaction open on the destination database file 6729** for the duration of the backup operation. 6730** ^The source database is read-locked only while it is being read; 6731** it is not locked continuously for the entire backup operation. 6732** ^Thus, the backup may be performed on a live source database without 6733** preventing other database connections from 6734** reading or writing to the source database while the backup is underway. 6735** 6736** ^(To perform a backup operation: 6737** <ol> 6738** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6739** backup, 6740** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6741** the data between the two databases, and finally 6742** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6743** associated with the backup operation. 6744** </ol>)^ 6745** There should be exactly one call to sqlite3_backup_finish() for each 6746** successful call to sqlite3_backup_init(). 6747** 6748** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6749** 6750** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6751** [database connection] associated with the destination database 6752** and the database name, respectively. 6753** ^The database name is "main" for the main database, "temp" for the 6754** temporary database, or the name specified after the AS keyword in 6755** an [ATTACH] statement for an attached database. 6756** ^The S and M arguments passed to 6757** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6758** and database name of the source database, respectively. 6759** ^The source and destination [database connections] (parameters S and D) 6760** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6761** an error. 6762** 6763** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6764** returned and an error code and error message are stored in the 6765** destination [database connection] D. 6766** ^The error code and message for the failed call to sqlite3_backup_init() 6767** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6768** [sqlite3_errmsg16()] functions. 6769** ^A successful call to sqlite3_backup_init() returns a pointer to an 6770** [sqlite3_backup] object. 6771** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6772** sqlite3_backup_finish() functions to perform the specified backup 6773** operation. 6774** 6775** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6776** 6777** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6778** the source and destination databases specified by [sqlite3_backup] object B. 6779** ^If N is negative, all remaining source pages are copied. 6780** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6781** are still more pages to be copied, then the function returns [SQLITE_OK]. 6782** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6783** from source to destination, then it returns [SQLITE_DONE]. 6784** ^If an error occurs while running sqlite3_backup_step(B,N), 6785** then an [error code] is returned. ^As well as [SQLITE_OK] and 6786** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6787** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6788** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6789** 6790** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6791** <ol> 6792** <li> the destination database was opened read-only, or 6793** <li> the destination database is using write-ahead-log journaling 6794** and the destination and source page sizes differ, or 6795** <li> the destination database is an in-memory database and the 6796** destination and source page sizes differ. 6797** </ol>)^ 6798** 6799** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6800** the [sqlite3_busy_handler | busy-handler function] 6801** is invoked (if one is specified). ^If the 6802** busy-handler returns non-zero before the lock is available, then 6803** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6804** sqlite3_backup_step() can be retried later. ^If the source 6805** [database connection] 6806** is being used to write to the source database when sqlite3_backup_step() 6807** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6808** case the call to sqlite3_backup_step() can be retried later on. ^(If 6809** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6810** [SQLITE_READONLY] is returned, then 6811** there is no point in retrying the call to sqlite3_backup_step(). These 6812** errors are considered fatal.)^ The application must accept 6813** that the backup operation has failed and pass the backup operation handle 6814** to the sqlite3_backup_finish() to release associated resources. 6815** 6816** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6817** on the destination file. ^The exclusive lock is not released until either 6818** sqlite3_backup_finish() is called or the backup operation is complete 6819** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6820** sqlite3_backup_step() obtains a [shared lock] on the source database that 6821** lasts for the duration of the sqlite3_backup_step() call. 6822** ^Because the source database is not locked between calls to 6823** sqlite3_backup_step(), the source database may be modified mid-way 6824** through the backup process. ^If the source database is modified by an 6825** external process or via a database connection other than the one being 6826** used by the backup operation, then the backup will be automatically 6827** restarted by the next call to sqlite3_backup_step(). ^If the source 6828** database is modified by the using the same database connection as is used 6829** by the backup operation, then the backup database is automatically 6830** updated at the same time. 6831** 6832** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6833** 6834** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6835** application wishes to abandon the backup operation, the application 6836** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6837** ^The sqlite3_backup_finish() interfaces releases all 6838** resources associated with the [sqlite3_backup] object. 6839** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6840** active write-transaction on the destination database is rolled back. 6841** The [sqlite3_backup] object is invalid 6842** and may not be used following a call to sqlite3_backup_finish(). 6843** 6844** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6845** sqlite3_backup_step() errors occurred, regardless or whether or not 6846** sqlite3_backup_step() completed. 6847** ^If an out-of-memory condition or IO error occurred during any prior 6848** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6849** sqlite3_backup_finish() returns the corresponding [error code]. 6850** 6851** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6852** is not a permanent error and does not affect the return value of 6853** sqlite3_backup_finish(). 6854** 6855** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6856** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6857** 6858** ^Each call to sqlite3_backup_step() sets two values inside 6859** the [sqlite3_backup] object: the number of pages still to be backed 6860** up and the total number of pages in the source database file. 6861** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6862** retrieve these two values, respectively. 6863** 6864** ^The values returned by these functions are only updated by 6865** sqlite3_backup_step(). ^If the source database is modified during a backup 6866** operation, then the values are not updated to account for any extra 6867** pages that need to be updated or the size of the source database file 6868** changing. 6869** 6870** <b>Concurrent Usage of Database Handles</b> 6871** 6872** ^The source [database connection] may be used by the application for other 6873** purposes while a backup operation is underway or being initialized. 6874** ^If SQLite is compiled and configured to support threadsafe database 6875** connections, then the source database connection may be used concurrently 6876** from within other threads. 6877** 6878** However, the application must guarantee that the destination 6879** [database connection] is not passed to any other API (by any thread) after 6880** sqlite3_backup_init() is called and before the corresponding call to 6881** sqlite3_backup_finish(). SQLite does not currently check to see 6882** if the application incorrectly accesses the destination [database connection] 6883** and so no error code is reported, but the operations may malfunction 6884** nevertheless. Use of the destination database connection while a 6885** backup is in progress might also also cause a mutex deadlock. 6886** 6887** If running in [shared cache mode], the application must 6888** guarantee that the shared cache used by the destination database 6889** is not accessed while the backup is running. In practice this means 6890** that the application must guarantee that the disk file being 6891** backed up to is not accessed by any connection within the process, 6892** not just the specific connection that was passed to sqlite3_backup_init(). 6893** 6894** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6895** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6896** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6897** APIs are not strictly speaking threadsafe. If they are invoked at the 6898** same time as another thread is invoking sqlite3_backup_step() it is 6899** possible that they return invalid values. 6900*/ 6901sqlite3_backup *sqlite3_backup_init( 6902 sqlite3 *pDest, /* Destination database handle */ 6903 const char *zDestName, /* Destination database name */ 6904 sqlite3 *pSource, /* Source database handle */ 6905 const char *zSourceName /* Source database name */ 6906); 6907int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6908int sqlite3_backup_finish(sqlite3_backup *p); 6909int sqlite3_backup_remaining(sqlite3_backup *p); 6910int sqlite3_backup_pagecount(sqlite3_backup *p); 6911 6912/* 6913** CAPI3REF: Unlock Notification 6914** 6915** ^When running in shared-cache mode, a database operation may fail with 6916** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6917** individual tables within the shared-cache cannot be obtained. See 6918** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6919** ^This API may be used to register a callback that SQLite will invoke 6920** when the connection currently holding the required lock relinquishes it. 6921** ^This API is only available if the library was compiled with the 6922** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6923** 6924** See Also: [Using the SQLite Unlock Notification Feature]. 6925** 6926** ^Shared-cache locks are released when a database connection concludes 6927** its current transaction, either by committing it or rolling it back. 6928** 6929** ^When a connection (known as the blocked connection) fails to obtain a 6930** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6931** identity of the database connection (the blocking connection) that 6932** has locked the required resource is stored internally. ^After an 6933** application receives an SQLITE_LOCKED error, it may call the 6934** sqlite3_unlock_notify() method with the blocked connection handle as 6935** the first argument to register for a callback that will be invoked 6936** when the blocking connections current transaction is concluded. ^The 6937** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6938** call that concludes the blocking connections transaction. 6939** 6940** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6941** there is a chance that the blocking connection will have already 6942** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6943** If this happens, then the specified callback is invoked immediately, 6944** from within the call to sqlite3_unlock_notify().)^ 6945** 6946** ^If the blocked connection is attempting to obtain a write-lock on a 6947** shared-cache table, and more than one other connection currently holds 6948** a read-lock on the same table, then SQLite arbitrarily selects one of 6949** the other connections to use as the blocking connection. 6950** 6951** ^(There may be at most one unlock-notify callback registered by a 6952** blocked connection. If sqlite3_unlock_notify() is called when the 6953** blocked connection already has a registered unlock-notify callback, 6954** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6955** called with a NULL pointer as its second argument, then any existing 6956** unlock-notify callback is canceled. ^The blocked connections 6957** unlock-notify callback may also be canceled by closing the blocked 6958** connection using [sqlite3_close()]. 6959** 6960** The unlock-notify callback is not reentrant. If an application invokes 6961** any sqlite3_xxx API functions from within an unlock-notify callback, a 6962** crash or deadlock may be the result. 6963** 6964** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6965** returns SQLITE_OK. 6966** 6967** <b>Callback Invocation Details</b> 6968** 6969** When an unlock-notify callback is registered, the application provides a 6970** single void* pointer that is passed to the callback when it is invoked. 6971** However, the signature of the callback function allows SQLite to pass 6972** it an array of void* context pointers. The first argument passed to 6973** an unlock-notify callback is a pointer to an array of void* pointers, 6974** and the second is the number of entries in the array. 6975** 6976** When a blocking connections transaction is concluded, there may be 6977** more than one blocked connection that has registered for an unlock-notify 6978** callback. ^If two or more such blocked connections have specified the 6979** same callback function, then instead of invoking the callback function 6980** multiple times, it is invoked once with the set of void* context pointers 6981** specified by the blocked connections bundled together into an array. 6982** This gives the application an opportunity to prioritize any actions 6983** related to the set of unblocked database connections. 6984** 6985** <b>Deadlock Detection</b> 6986** 6987** Assuming that after registering for an unlock-notify callback a 6988** database waits for the callback to be issued before taking any further 6989** action (a reasonable assumption), then using this API may cause the 6990** application to deadlock. For example, if connection X is waiting for 6991** connection Y's transaction to be concluded, and similarly connection 6992** Y is waiting on connection X's transaction, then neither connection 6993** will proceed and the system may remain deadlocked indefinitely. 6994** 6995** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6996** detection. ^If a given call to sqlite3_unlock_notify() would put the 6997** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6998** unlock-notify callback is registered. The system is said to be in 6999** a deadlocked state if connection A has registered for an unlock-notify 7000** callback on the conclusion of connection B's transaction, and connection 7001** B has itself registered for an unlock-notify callback when connection 7002** A's transaction is concluded. ^Indirect deadlock is also detected, so 7003** the system is also considered to be deadlocked if connection B has 7004** registered for an unlock-notify callback on the conclusion of connection 7005** C's transaction, where connection C is waiting on connection A. ^Any 7006** number of levels of indirection are allowed. 7007** 7008** <b>The "DROP TABLE" Exception</b> 7009** 7010** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7011** always appropriate to call sqlite3_unlock_notify(). There is however, 7012** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7013** SQLite checks if there are any currently executing SELECT statements 7014** that belong to the same connection. If there are, SQLITE_LOCKED is 7015** returned. In this case there is no "blocking connection", so invoking 7016** sqlite3_unlock_notify() results in the unlock-notify callback being 7017** invoked immediately. If the application then re-attempts the "DROP TABLE" 7018** or "DROP INDEX" query, an infinite loop might be the result. 7019** 7020** One way around this problem is to check the extended error code returned 7021** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7022** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7023** the special "DROP TABLE/INDEX" case, the extended error code is just 7024** SQLITE_LOCKED.)^ 7025*/ 7026int sqlite3_unlock_notify( 7027 sqlite3 *pBlocked, /* Waiting connection */ 7028 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7029 void *pNotifyArg /* Argument to pass to xNotify */ 7030); 7031 7032 7033/* 7034** CAPI3REF: String Comparison 7035** 7036** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7037** and extensions to compare the contents of two buffers containing UTF-8 7038** strings in a case-independent fashion, using the same definition of "case 7039** independence" that SQLite uses internally when comparing identifiers. 7040*/ 7041int sqlite3_stricmp(const char *, const char *); 7042int sqlite3_strnicmp(const char *, const char *, int); 7043 7044/* 7045** CAPI3REF: String Globbing 7046* 7047** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches 7048** the glob pattern P, and it returns non-zero if string X does not match 7049** the glob pattern P. ^The definition of glob pattern matching used in 7050** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7051** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case 7052** sensitive. 7053** 7054** Note that this routine returns zero on a match and non-zero if the strings 7055** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7056*/ 7057int sqlite3_strglob(const char *zGlob, const char *zStr); 7058 7059/* 7060** CAPI3REF: Error Logging Interface 7061** 7062** ^The [sqlite3_log()] interface writes a message into the [error log] 7063** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7064** ^If logging is enabled, the zFormat string and subsequent arguments are 7065** used with [sqlite3_snprintf()] to generate the final output string. 7066** 7067** The sqlite3_log() interface is intended for use by extensions such as 7068** virtual tables, collating functions, and SQL functions. While there is 7069** nothing to prevent an application from calling sqlite3_log(), doing so 7070** is considered bad form. 7071** 7072** The zFormat string must not be NULL. 7073** 7074** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7075** will not use dynamically allocated memory. The log message is stored in 7076** a fixed-length buffer on the stack. If the log message is longer than 7077** a few hundred characters, it will be truncated to the length of the 7078** buffer. 7079*/ 7080void sqlite3_log(int iErrCode, const char *zFormat, ...); 7081 7082/* 7083** CAPI3REF: Write-Ahead Log Commit Hook 7084** 7085** ^The [sqlite3_wal_hook()] function is used to register a callback that 7086** will be invoked each time a database connection commits data to a 7087** [write-ahead log] (i.e. whenever a transaction is committed in 7088** [journal_mode | journal_mode=WAL mode]). 7089** 7090** ^The callback is invoked by SQLite after the commit has taken place and 7091** the associated write-lock on the database released, so the implementation 7092** may read, write or [checkpoint] the database as required. 7093** 7094** ^The first parameter passed to the callback function when it is invoked 7095** is a copy of the third parameter passed to sqlite3_wal_hook() when 7096** registering the callback. ^The second is a copy of the database handle. 7097** ^The third parameter is the name of the database that was written to - 7098** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7099** is the number of pages currently in the write-ahead log file, 7100** including those that were just committed. 7101** 7102** The callback function should normally return [SQLITE_OK]. ^If an error 7103** code is returned, that error will propagate back up through the 7104** SQLite code base to cause the statement that provoked the callback 7105** to report an error, though the commit will have still occurred. If the 7106** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7107** that does not correspond to any valid SQLite error code, the results 7108** are undefined. 7109** 7110** A single database handle may have at most a single write-ahead log callback 7111** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7112** previously registered write-ahead log callback. ^Note that the 7113** [sqlite3_wal_autocheckpoint()] interface and the 7114** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7115** those overwrite any prior [sqlite3_wal_hook()] settings. 7116*/ 7117void *sqlite3_wal_hook( 7118 sqlite3*, 7119 int(*)(void *,sqlite3*,const char*,int), 7120 void* 7121); 7122 7123/* 7124** CAPI3REF: Configure an auto-checkpoint 7125** 7126** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 7127** [sqlite3_wal_hook()] that causes any database on [database connection] D 7128** to automatically [checkpoint] 7129** after committing a transaction if there are N or 7130** more frames in the [write-ahead log] file. ^Passing zero or 7131** a negative value as the nFrame parameter disables automatic 7132** checkpoints entirely. 7133** 7134** ^The callback registered by this function replaces any existing callback 7135** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 7136** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 7137** configured by this function. 7138** 7139** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 7140** from SQL. 7141** 7142** ^Every new [database connection] defaults to having the auto-checkpoint 7143** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 7144** pages. The use of this interface 7145** is only necessary if the default setting is found to be suboptimal 7146** for a particular application. 7147*/ 7148int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 7149 7150/* 7151** CAPI3REF: Checkpoint a database 7152** 7153** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 7154** on [database connection] D to be [checkpointed]. ^If X is NULL or an 7155** empty string, then a checkpoint is run on all databases of 7156** connection D. ^If the database connection D is not in 7157** [WAL | write-ahead log mode] then this interface is a harmless no-op. 7158** 7159** ^The [wal_checkpoint pragma] can be used to invoke this interface 7160** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 7161** [wal_autocheckpoint pragma] can be used to cause this interface to be 7162** run whenever the WAL reaches a certain size threshold. 7163** 7164** See also: [sqlite3_wal_checkpoint_v2()] 7165*/ 7166int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 7167 7168/* 7169** CAPI3REF: Checkpoint a database 7170** 7171** Run a checkpoint operation on WAL database zDb attached to database 7172** handle db. The specific operation is determined by the value of the 7173** eMode parameter: 7174** 7175** <dl> 7176** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7177** Checkpoint as many frames as possible without waiting for any database 7178** readers or writers to finish. Sync the db file if all frames in the log 7179** are checkpointed. This mode is the same as calling 7180** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 7181** 7182** <dt>SQLITE_CHECKPOINT_FULL<dd> 7183** This mode blocks (calls the busy-handler callback) until there is no 7184** database writer and all readers are reading from the most recent database 7185** snapshot. It then checkpoints all frames in the log file and syncs the 7186** database file. This call blocks database writers while it is running, 7187** but not database readers. 7188** 7189** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7190** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 7191** checkpointing the log file it blocks (calls the busy-handler callback) 7192** until all readers are reading from the database file only. This ensures 7193** that the next client to write to the database file restarts the log file 7194** from the beginning. This call blocks database writers while it is running, 7195** but not database readers. 7196** </dl> 7197** 7198** If pnLog is not NULL, then *pnLog is set to the total number of frames in 7199** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 7200** the total number of checkpointed frames (including any that were already 7201** checkpointed when this function is called). *pnLog and *pnCkpt may be 7202** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 7203** If no values are available because of an error, they are both set to -1 7204** before returning to communicate this to the caller. 7205** 7206** All calls obtain an exclusive "checkpoint" lock on the database file. If 7207** any other process is running a checkpoint operation at the same time, the 7208** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 7209** busy-handler configured, it will not be invoked in this case. 7210** 7211** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 7212** "writer" lock on the database file. If the writer lock cannot be obtained 7213** immediately, and a busy-handler is configured, it is invoked and the writer 7214** lock retried until either the busy-handler returns 0 or the lock is 7215** successfully obtained. The busy-handler is also invoked while waiting for 7216** database readers as described above. If the busy-handler returns 0 before 7217** the writer lock is obtained or while waiting for database readers, the 7218** checkpoint operation proceeds from that point in the same way as 7219** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7220** without blocking any further. SQLITE_BUSY is returned in this case. 7221** 7222** If parameter zDb is NULL or points to a zero length string, then the 7223** specified operation is attempted on all WAL databases. In this case the 7224** values written to output parameters *pnLog and *pnCkpt are undefined. If 7225** an SQLITE_BUSY error is encountered when processing one or more of the 7226** attached WAL databases, the operation is still attempted on any remaining 7227** attached databases and SQLITE_BUSY is returned to the caller. If any other 7228** error occurs while processing an attached database, processing is abandoned 7229** and the error code returned to the caller immediately. If no error 7230** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7231** databases, SQLITE_OK is returned. 7232** 7233** If database zDb is the name of an attached database that is not in WAL 7234** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 7235** zDb is not NULL (or a zero length string) and is not the name of any 7236** attached database, SQLITE_ERROR is returned to the caller. 7237*/ 7238int sqlite3_wal_checkpoint_v2( 7239 sqlite3 *db, /* Database handle */ 7240 const char *zDb, /* Name of attached database (or NULL) */ 7241 int eMode, /* SQLITE_CHECKPOINT_* value */ 7242 int *pnLog, /* OUT: Size of WAL log in frames */ 7243 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7244); 7245 7246/* 7247** CAPI3REF: Checkpoint operation parameters 7248** 7249** These constants can be used as the 3rd parameter to 7250** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 7251** documentation for additional information about the meaning and use of 7252** each of these values. 7253*/ 7254#define SQLITE_CHECKPOINT_PASSIVE 0 7255#define SQLITE_CHECKPOINT_FULL 1 7256#define SQLITE_CHECKPOINT_RESTART 2 7257 7258/* 7259** CAPI3REF: Virtual Table Interface Configuration 7260** 7261** This function may be called by either the [xConnect] or [xCreate] method 7262** of a [virtual table] implementation to configure 7263** various facets of the virtual table interface. 7264** 7265** If this interface is invoked outside the context of an xConnect or 7266** xCreate virtual table method then the behavior is undefined. 7267** 7268** At present, there is only one option that may be configured using 7269** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7270** may be added in the future. 7271*/ 7272int sqlite3_vtab_config(sqlite3*, int op, ...); 7273 7274/* 7275** CAPI3REF: Virtual Table Configuration Options 7276** 7277** These macros define the various options to the 7278** [sqlite3_vtab_config()] interface that [virtual table] implementations 7279** can use to customize and optimize their behavior. 7280** 7281** <dl> 7282** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7283** <dd>Calls of the form 7284** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7285** where X is an integer. If X is zero, then the [virtual table] whose 7286** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7287** support constraints. In this configuration (which is the default) if 7288** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7289** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7290** specified as part of the users SQL statement, regardless of the actual 7291** ON CONFLICT mode specified. 7292** 7293** If X is non-zero, then the virtual table implementation guarantees 7294** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7295** any modifications to internal or persistent data structures have been made. 7296** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7297** is able to roll back a statement or database transaction, and abandon 7298** or continue processing the current SQL statement as appropriate. 7299** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7300** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7301** had been ABORT. 7302** 7303** Virtual table implementations that are required to handle OR REPLACE 7304** must do so within the [xUpdate] method. If a call to the 7305** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7306** CONFLICT policy is REPLACE, the virtual table implementation should 7307** silently replace the appropriate rows within the xUpdate callback and 7308** return SQLITE_OK. Or, if this is not possible, it may return 7309** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7310** constraint handling. 7311** </dl> 7312*/ 7313#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7314 7315/* 7316** CAPI3REF: Determine The Virtual Table Conflict Policy 7317** 7318** This function may only be called from within a call to the [xUpdate] method 7319** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7320** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7321** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7322** of the SQL statement that triggered the call to the [xUpdate] method of the 7323** [virtual table]. 7324*/ 7325int sqlite3_vtab_on_conflict(sqlite3 *); 7326 7327/* 7328** CAPI3REF: Conflict resolution modes 7329** 7330** These constants are returned by [sqlite3_vtab_on_conflict()] to 7331** inform a [virtual table] implementation what the [ON CONFLICT] mode 7332** is for the SQL statement being evaluated. 7333** 7334** Note that the [SQLITE_IGNORE] constant is also used as a potential 7335** return value from the [sqlite3_set_authorizer()] callback and that 7336** [SQLITE_ABORT] is also a [result code]. 7337*/ 7338#define SQLITE_ROLLBACK 1 7339/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7340#define SQLITE_FAIL 3 7341/* #define SQLITE_ABORT 4 // Also an error code */ 7342#define SQLITE_REPLACE 5 7343 7344 7345 7346/* 7347** Undo the hack that converts floating point types to integer for 7348** builds on processors without floating point support. 7349*/ 7350#ifdef SQLITE_OMIT_FLOATING_POINT 7351# undef double 7352#endif 7353 7354#ifdef __cplusplus 7355} /* End of the 'extern "C"' block */ 7356#endif 7357#endif /* _SQLITE3_H_ */ 7358