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