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 supposed 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** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_STDCALL 58# define SQLITE_STDCALL 59#endif 60 61/* 62** These no-op macros are used in front of interfaces to mark those 63** interfaces as either deprecated or experimental. New applications 64** should not use deprecated interfaces - they are supported for backwards 65** compatibility only. Application writers should be aware that 66** experimental interfaces are subject to change in point releases. 67** 68** These macros used to resolve to various kinds of compiler magic that 69** would generate warning messages when they were used. But that 70** compiler magic ended up generating such a flurry of bug reports 71** that we have taken it all out and gone back to using simple 72** noop macros. 73*/ 74#define SQLITE_DEPRECATED 75#define SQLITE_EXPERIMENTAL 76 77/* 78** Ensure these symbols were not defined by some previous header file. 79*/ 80#ifdef SQLITE_VERSION 81# undef SQLITE_VERSION 82#endif 83#ifdef SQLITE_VERSION_NUMBER 84# undef SQLITE_VERSION_NUMBER 85#endif 86 87/* 88** CAPI3REF: Compile-Time Library Version Numbers 89** 90** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 91** evaluates to a string literal that is the SQLite version in the 92** format "X.Y.Z" where X is the major version number (always 3 for 93** SQLite3) and Y is the minor version number and Z is the release number.)^ 94** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 95** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 96** numbers used in [SQLITE_VERSION].)^ 97** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 98** be larger than the release from which it is derived. Either Y will 99** be held constant and Z will be incremented or else Y will be incremented 100** and Z will be reset to zero. 101** 102** Since version 3.6.18, SQLite source code has been stored in the 103** <a href="http://www.fossil-scm.org/">Fossil configuration management 104** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 105** a string which identifies a particular check-in of SQLite 106** within its configuration management system. ^The SQLITE_SOURCE_ID 107** string contains the date and time of the check-in (UTC) and an SHA1 108** hash of the entire source tree. 109** 110** See also: [sqlite3_libversion()], 111** [sqlite3_libversion_number()], [sqlite3_sourceid()], 112** [sqlite_version()] and [sqlite_source_id()]. 113*/ 114#define SQLITE_VERSION "3.9.2" 115#define SQLITE_VERSION_NUMBER 3009002 116#define SQLITE_SOURCE_ID "2015-11-02 18:31:45 bda77dda9697c463c3d0704014d51627fceee328" 117 118/* 119** CAPI3REF: Run-Time Library Version Numbers 120** KEYWORDS: sqlite3_version, sqlite3_sourceid 121** 122** These interfaces provide the same information as the [SQLITE_VERSION], 123** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 124** but are associated with the library instead of the header file. ^(Cautious 125** programmers might include assert() statements in their application to 126** verify that values returned by these interfaces match the macros in 127** the header, and thus ensure that the application is 128** compiled with matching library and header files. 129** 130** <blockquote><pre> 131** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 132** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 133** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 134** </pre></blockquote>)^ 135** 136** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 137** macro. ^The sqlite3_libversion() function returns a pointer to the 138** to the sqlite3_version[] string constant. The sqlite3_libversion() 139** function is provided for use in DLLs since DLL users usually do not have 140** direct access to string constants within the DLL. ^The 141** sqlite3_libversion_number() function returns an integer equal to 142** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 143** a pointer to a string constant whose value is the same as the 144** [SQLITE_SOURCE_ID] C preprocessor macro. 145** 146** See also: [sqlite_version()] and [sqlite_source_id()]. 147*/ 148SQLITE_API SQLITE_EXTERN const char sqlite3_version[]; 149SQLITE_API const char *SQLITE_STDCALL sqlite3_libversion(void); 150SQLITE_API const char *SQLITE_STDCALL sqlite3_sourceid(void); 151SQLITE_API int SQLITE_STDCALL sqlite3_libversion_number(void); 152 153/* 154** CAPI3REF: Run-Time Library Compilation Options Diagnostics 155** 156** ^The sqlite3_compileoption_used() function returns 0 or 1 157** indicating whether the specified option was defined at 158** compile time. ^The SQLITE_ prefix may be omitted from the 159** option name passed to sqlite3_compileoption_used(). 160** 161** ^The sqlite3_compileoption_get() function allows iterating 162** over the list of options that were defined at compile time by 163** returning the N-th compile time option string. ^If N is out of range, 164** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 165** prefix is omitted from any strings returned by 166** sqlite3_compileoption_get(). 167** 168** ^Support for the diagnostic functions sqlite3_compileoption_used() 169** and sqlite3_compileoption_get() may be omitted by specifying the 170** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 171** 172** See also: SQL functions [sqlite_compileoption_used()] and 173** [sqlite_compileoption_get()] and the [compile_options pragma]. 174*/ 175#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 176SQLITE_API int SQLITE_STDCALL sqlite3_compileoption_used(const char *zOptName); 177SQLITE_API const char *SQLITE_STDCALL sqlite3_compileoption_get(int N); 178#endif 179 180/* 181** CAPI3REF: Test To See If The Library Is Threadsafe 182** 183** ^The sqlite3_threadsafe() function returns zero if and only if 184** SQLite was compiled with mutexing code omitted due to the 185** [SQLITE_THREADSAFE] compile-time option being set to 0. 186** 187** SQLite can be compiled with or without mutexes. When 188** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 189** are enabled and SQLite is threadsafe. When the 190** [SQLITE_THREADSAFE] macro is 0, 191** the mutexes are omitted. Without the mutexes, it is not safe 192** to use SQLite concurrently from more than one thread. 193** 194** Enabling mutexes incurs a measurable performance penalty. 195** So if speed is of utmost importance, it makes sense to disable 196** the mutexes. But for maximum safety, mutexes should be enabled. 197** ^The default behavior is for mutexes to be enabled. 198** 199** This interface can be used by an application to make sure that the 200** version of SQLite that it is linking against was compiled with 201** the desired setting of the [SQLITE_THREADSAFE] macro. 202** 203** This interface only reports on the compile-time mutex setting 204** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 205** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 206** can be fully or partially disabled using a call to [sqlite3_config()] 207** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 208** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 209** sqlite3_threadsafe() function shows only the compile-time setting of 210** thread safety, not any run-time changes to that setting made by 211** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 212** is unchanged by calls to sqlite3_config().)^ 213** 214** See the [threading mode] documentation for additional information. 215*/ 216SQLITE_API int SQLITE_STDCALL sqlite3_threadsafe(void); 217 218/* 219** CAPI3REF: Database Connection Handle 220** KEYWORDS: {database connection} {database connections} 221** 222** Each open SQLite database is represented by a pointer to an instance of 223** the opaque structure named "sqlite3". It is useful to think of an sqlite3 224** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 225** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 226** and [sqlite3_close_v2()] are its destructors. There are many other 227** interfaces (such as 228** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 229** [sqlite3_busy_timeout()] to name but three) that are methods on an 230** sqlite3 object. 231*/ 232typedef struct sqlite3 sqlite3; 233 234/* 235** CAPI3REF: 64-Bit Integer Types 236** KEYWORDS: sqlite_int64 sqlite_uint64 237** 238** Because there is no cross-platform way to specify 64-bit integer types 239** SQLite includes typedefs for 64-bit signed and unsigned integers. 240** 241** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 242** The sqlite_int64 and sqlite_uint64 types are supported for backwards 243** compatibility only. 244** 245** ^The sqlite3_int64 and sqlite_int64 types can store integer values 246** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 247** sqlite3_uint64 and sqlite_uint64 types can store integer values 248** between 0 and +18446744073709551615 inclusive. 249*/ 250#ifdef SQLITE_INT64_TYPE 251 typedef SQLITE_INT64_TYPE sqlite_int64; 252 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 253#elif defined(_MSC_VER) || defined(__BORLANDC__) 254 typedef __int64 sqlite_int64; 255 typedef unsigned __int64 sqlite_uint64; 256#else 257 typedef long long int sqlite_int64; 258 typedef unsigned long long int sqlite_uint64; 259#endif 260typedef sqlite_int64 sqlite3_int64; 261typedef sqlite_uint64 sqlite3_uint64; 262 263/* 264** If compiling for a processor that lacks floating point support, 265** substitute integer for floating-point. 266*/ 267#ifdef SQLITE_OMIT_FLOATING_POINT 268# define double sqlite3_int64 269#endif 270 271/* 272** CAPI3REF: Closing A Database Connection 273** DESTRUCTOR: sqlite3 274** 275** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 276** for the [sqlite3] object. 277** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 278** the [sqlite3] object is successfully destroyed and all associated 279** resources are deallocated. 280** 281** ^If the database connection is associated with unfinalized prepared 282** statements or unfinished sqlite3_backup objects then sqlite3_close() 283** will leave the database connection open and return [SQLITE_BUSY]. 284** ^If sqlite3_close_v2() is called with unfinalized prepared statements 285** and/or unfinished sqlite3_backups, then the database connection becomes 286** an unusable "zombie" which will automatically be deallocated when the 287** last prepared statement is finalized or the last sqlite3_backup is 288** finished. The sqlite3_close_v2() interface is intended for use with 289** host languages that are garbage collected, and where the order in which 290** destructors are called is arbitrary. 291** 292** Applications should [sqlite3_finalize | finalize] all [prepared statements], 293** [sqlite3_blob_close | close] all [BLOB handles], and 294** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 295** with the [sqlite3] object prior to attempting to close the object. ^If 296** sqlite3_close_v2() is called on a [database connection] that still has 297** outstanding [prepared statements], [BLOB handles], and/or 298** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 299** of resources is deferred until all [prepared statements], [BLOB handles], 300** and [sqlite3_backup] objects are also destroyed. 301** 302** ^If an [sqlite3] object is destroyed while a transaction is open, 303** the transaction is automatically rolled back. 304** 305** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 306** must be either a NULL 307** pointer or an [sqlite3] object pointer obtained 308** from [sqlite3_open()], [sqlite3_open16()], or 309** [sqlite3_open_v2()], and not previously closed. 310** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 311** argument is a harmless no-op. 312*/ 313SQLITE_API int SQLITE_STDCALL sqlite3_close(sqlite3*); 314SQLITE_API int SQLITE_STDCALL sqlite3_close_v2(sqlite3*); 315 316/* 317** The type for a callback function. 318** This is legacy and deprecated. It is included for historical 319** compatibility and is not documented. 320*/ 321typedef int (*sqlite3_callback)(void*,int,char**, char**); 322 323/* 324** CAPI3REF: One-Step Query Execution Interface 325** METHOD: sqlite3 326** 327** The sqlite3_exec() interface is a convenience wrapper around 328** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 329** that allows an application to run multiple statements of SQL 330** without having to use a lot of C code. 331** 332** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 333** semicolon-separate SQL statements passed into its 2nd argument, 334** in the context of the [database connection] passed in as its 1st 335** argument. ^If the callback function of the 3rd argument to 336** sqlite3_exec() is not NULL, then it is invoked for each result row 337** coming out of the evaluated SQL statements. ^The 4th argument to 338** sqlite3_exec() is relayed through to the 1st argument of each 339** callback invocation. ^If the callback pointer to sqlite3_exec() 340** is NULL, then no callback is ever invoked and result rows are 341** ignored. 342** 343** ^If an error occurs while evaluating the SQL statements passed into 344** sqlite3_exec(), then execution of the current statement stops and 345** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 346** is not NULL then any error message is written into memory obtained 347** from [sqlite3_malloc()] and passed back through the 5th parameter. 348** To avoid memory leaks, the application should invoke [sqlite3_free()] 349** on error message strings returned through the 5th parameter of 350** of sqlite3_exec() after the error message string is no longer needed. 351** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 352** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 353** NULL before returning. 354** 355** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 356** routine returns SQLITE_ABORT without invoking the callback again and 357** without running any subsequent SQL statements. 358** 359** ^The 2nd argument to the sqlite3_exec() callback function is the 360** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 361** callback is an array of pointers to strings obtained as if from 362** [sqlite3_column_text()], one for each column. ^If an element of a 363** result row is NULL then the corresponding string pointer for the 364** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 365** sqlite3_exec() callback is an array of pointers to strings where each 366** entry represents the name of corresponding result column as obtained 367** from [sqlite3_column_name()]. 368** 369** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 370** to an empty string, or a pointer that contains only whitespace and/or 371** SQL comments, then no SQL statements are evaluated and the database 372** is not changed. 373** 374** Restrictions: 375** 376** <ul> 377** <li> The application must ensure that the 1st parameter to sqlite3_exec() 378** is a valid and open [database connection]. 379** <li> The application must not close the [database connection] specified by 380** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 381** <li> The application must not modify the SQL statement text passed into 382** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 383** </ul> 384*/ 385SQLITE_API int SQLITE_STDCALL sqlite3_exec( 386 sqlite3*, /* An open database */ 387 const char *sql, /* SQL to be evaluated */ 388 int (*callback)(void*,int,char**,char**), /* Callback function */ 389 void *, /* 1st argument to callback */ 390 char **errmsg /* Error msg written here */ 391); 392 393/* 394** CAPI3REF: Result Codes 395** KEYWORDS: {result code definitions} 396** 397** Many SQLite functions return an integer result code from the set shown 398** here in order to indicate success or failure. 399** 400** New error codes may be added in future versions of SQLite. 401** 402** See also: [extended result code definitions] 403*/ 404#define SQLITE_OK 0 /* Successful result */ 405/* beginning-of-error-codes */ 406#define SQLITE_ERROR 1 /* SQL error or missing database */ 407#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 408#define SQLITE_PERM 3 /* Access permission denied */ 409#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 410#define SQLITE_BUSY 5 /* The database file is locked */ 411#define SQLITE_LOCKED 6 /* A table in the database is locked */ 412#define SQLITE_NOMEM 7 /* A malloc() failed */ 413#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 414#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 415#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 416#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 417#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 418#define SQLITE_FULL 13 /* Insertion failed because database is full */ 419#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 420#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 421#define SQLITE_EMPTY 16 /* Database is empty */ 422#define SQLITE_SCHEMA 17 /* The database schema changed */ 423#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 424#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 425#define SQLITE_MISMATCH 20 /* Data type mismatch */ 426#define SQLITE_MISUSE 21 /* Library used incorrectly */ 427#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 428#define SQLITE_AUTH 23 /* Authorization denied */ 429#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 430#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 431#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 432#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 433#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 434#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 435#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 436/* end-of-error-codes */ 437 438/* 439** CAPI3REF: Extended Result Codes 440** KEYWORDS: {extended result code definitions} 441** 442** In its default configuration, SQLite API routines return one of 30 integer 443** [result codes]. However, experience has shown that many of 444** these result codes are too coarse-grained. They do not provide as 445** much information about problems as programmers might like. In an effort to 446** address this, newer versions of SQLite (version 3.3.8 and later) include 447** support for additional result codes that provide more detailed information 448** about errors. These [extended result codes] are enabled or disabled 449** on a per database connection basis using the 450** [sqlite3_extended_result_codes()] API. Or, the extended code for 451** the most recent error can be obtained using 452** [sqlite3_extended_errcode()]. 453*/ 454#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 455#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 456#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 457#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 458#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 459#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 460#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 461#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 462#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 463#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 464#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 465#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 466#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 467#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 468#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 469#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 470#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 471#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 472#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 473#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 474#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 475#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 476#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 477#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 478#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 479#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 480#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 481#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 482#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 483#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 484#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 485#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 486#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 487#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 488#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 489#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 490#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 491#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 492#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 493#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 494#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 495#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 496#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 497#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 498#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 499#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 500#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 501#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 502#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 503#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 504#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 505#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 506#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 507#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 508 509/* 510** CAPI3REF: Flags For File Open Operations 511** 512** These bit values are intended for use in the 513** 3rd parameter to the [sqlite3_open_v2()] interface and 514** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 515*/ 516#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 517#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 518#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 519#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 520#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 521#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 522#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 523#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 524#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 525#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 526#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 527#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 528#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 529#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 530#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 531#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 532#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 533#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 534#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 535#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 536 537/* Reserved: 0x00F00000 */ 538 539/* 540** CAPI3REF: Device Characteristics 541** 542** The xDeviceCharacteristics method of the [sqlite3_io_methods] 543** object returns an integer which is a vector of these 544** bit values expressing I/O characteristics of the mass storage 545** device that holds the file that the [sqlite3_io_methods] 546** refers to. 547** 548** The SQLITE_IOCAP_ATOMIC property means that all writes of 549** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 550** mean that writes of blocks that are nnn bytes in size and 551** are aligned to an address which is an integer multiple of 552** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 553** that when data is appended to a file, the data is appended 554** first then the size of the file is extended, never the other 555** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 556** information is written to disk in the same order as calls 557** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 558** after reboot following a crash or power loss, the only bytes in a 559** file that were written at the application level might have changed 560** and that adjacent bytes, even bytes within the same sector are 561** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 562** flag indicate that a file cannot be deleted when open. The 563** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 564** read-only media and cannot be changed even by processes with 565** elevated privileges. 566*/ 567#define SQLITE_IOCAP_ATOMIC 0x00000001 568#define SQLITE_IOCAP_ATOMIC512 0x00000002 569#define SQLITE_IOCAP_ATOMIC1K 0x00000004 570#define SQLITE_IOCAP_ATOMIC2K 0x00000008 571#define SQLITE_IOCAP_ATOMIC4K 0x00000010 572#define SQLITE_IOCAP_ATOMIC8K 0x00000020 573#define SQLITE_IOCAP_ATOMIC16K 0x00000040 574#define SQLITE_IOCAP_ATOMIC32K 0x00000080 575#define SQLITE_IOCAP_ATOMIC64K 0x00000100 576#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 577#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 578#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 579#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 580#define SQLITE_IOCAP_IMMUTABLE 0x00002000 581 582/* 583** CAPI3REF: File Locking Levels 584** 585** SQLite uses one of these integer values as the second 586** argument to calls it makes to the xLock() and xUnlock() methods 587** of an [sqlite3_io_methods] object. 588*/ 589#define SQLITE_LOCK_NONE 0 590#define SQLITE_LOCK_SHARED 1 591#define SQLITE_LOCK_RESERVED 2 592#define SQLITE_LOCK_PENDING 3 593#define SQLITE_LOCK_EXCLUSIVE 4 594 595/* 596** CAPI3REF: Synchronization Type Flags 597** 598** When SQLite invokes the xSync() method of an 599** [sqlite3_io_methods] object it uses a combination of 600** these integer values as the second argument. 601** 602** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 603** sync operation only needs to flush data to mass storage. Inode 604** information need not be flushed. If the lower four bits of the flag 605** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 606** If the lower four bits equal SQLITE_SYNC_FULL, that means 607** to use Mac OS X style fullsync instead of fsync(). 608** 609** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 610** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 611** settings. The [synchronous pragma] determines when calls to the 612** xSync VFS method occur and applies uniformly across all platforms. 613** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 614** energetic or rigorous or forceful the sync operations are and 615** only make a difference on Mac OSX for the default SQLite code. 616** (Third-party VFS implementations might also make the distinction 617** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 618** operating systems natively supported by SQLite, only Mac OSX 619** cares about the difference.) 620*/ 621#define SQLITE_SYNC_NORMAL 0x00002 622#define SQLITE_SYNC_FULL 0x00003 623#define SQLITE_SYNC_DATAONLY 0x00010 624 625/* 626** CAPI3REF: OS Interface Open File Handle 627** 628** An [sqlite3_file] object represents an open file in the 629** [sqlite3_vfs | OS interface layer]. Individual OS interface 630** implementations will 631** want to subclass this object by appending additional fields 632** for their own use. The pMethods entry is a pointer to an 633** [sqlite3_io_methods] object that defines methods for performing 634** I/O operations on the open file. 635*/ 636typedef struct sqlite3_file sqlite3_file; 637struct sqlite3_file { 638 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 639}; 640 641/* 642** CAPI3REF: OS Interface File Virtual Methods Object 643** 644** Every file opened by the [sqlite3_vfs.xOpen] method populates an 645** [sqlite3_file] object (or, more commonly, a subclass of the 646** [sqlite3_file] object) with a pointer to an instance of this object. 647** This object defines the methods used to perform various operations 648** against the open file represented by the [sqlite3_file] object. 649** 650** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 651** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 652** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 653** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 654** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 655** to NULL. 656** 657** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 658** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 659** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 660** flag may be ORed in to indicate that only the data of the file 661** and not its inode needs to be synced. 662** 663** The integer values to xLock() and xUnlock() are one of 664** <ul> 665** <li> [SQLITE_LOCK_NONE], 666** <li> [SQLITE_LOCK_SHARED], 667** <li> [SQLITE_LOCK_RESERVED], 668** <li> [SQLITE_LOCK_PENDING], or 669** <li> [SQLITE_LOCK_EXCLUSIVE]. 670** </ul> 671** xLock() increases the lock. xUnlock() decreases the lock. 672** The xCheckReservedLock() method checks whether any database connection, 673** either in this process or in some other process, is holding a RESERVED, 674** PENDING, or EXCLUSIVE lock on the file. It returns true 675** if such a lock exists and false otherwise. 676** 677** The xFileControl() method is a generic interface that allows custom 678** VFS implementations to directly control an open file using the 679** [sqlite3_file_control()] interface. The second "op" argument is an 680** integer opcode. The third argument is a generic pointer intended to 681** point to a structure that may contain arguments or space in which to 682** write return values. Potential uses for xFileControl() might be 683** functions to enable blocking locks with timeouts, to change the 684** locking strategy (for example to use dot-file locks), to inquire 685** about the status of a lock, or to break stale locks. The SQLite 686** core reserves all opcodes less than 100 for its own use. 687** A [file control opcodes | list of opcodes] less than 100 is available. 688** Applications that define a custom xFileControl method should use opcodes 689** greater than 100 to avoid conflicts. VFS implementations should 690** return [SQLITE_NOTFOUND] for file control opcodes that they do not 691** recognize. 692** 693** The xSectorSize() method returns the sector size of the 694** device that underlies the file. The sector size is the 695** minimum write that can be performed without disturbing 696** other bytes in the file. The xDeviceCharacteristics() 697** method returns a bit vector describing behaviors of the 698** underlying device: 699** 700** <ul> 701** <li> [SQLITE_IOCAP_ATOMIC] 702** <li> [SQLITE_IOCAP_ATOMIC512] 703** <li> [SQLITE_IOCAP_ATOMIC1K] 704** <li> [SQLITE_IOCAP_ATOMIC2K] 705** <li> [SQLITE_IOCAP_ATOMIC4K] 706** <li> [SQLITE_IOCAP_ATOMIC8K] 707** <li> [SQLITE_IOCAP_ATOMIC16K] 708** <li> [SQLITE_IOCAP_ATOMIC32K] 709** <li> [SQLITE_IOCAP_ATOMIC64K] 710** <li> [SQLITE_IOCAP_SAFE_APPEND] 711** <li> [SQLITE_IOCAP_SEQUENTIAL] 712** </ul> 713** 714** The SQLITE_IOCAP_ATOMIC property means that all writes of 715** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 716** mean that writes of blocks that are nnn bytes in size and 717** are aligned to an address which is an integer multiple of 718** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 719** that when data is appended to a file, the data is appended 720** first then the size of the file is extended, never the other 721** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 722** information is written to disk in the same order as calls 723** to xWrite(). 724** 725** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 726** in the unread portions of the buffer with zeros. A VFS that 727** fails to zero-fill short reads might seem to work. However, 728** failure to zero-fill short reads will eventually lead to 729** database corruption. 730*/ 731typedef struct sqlite3_io_methods sqlite3_io_methods; 732struct sqlite3_io_methods { 733 int iVersion; 734 int (*xClose)(sqlite3_file*); 735 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 736 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 737 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 738 int (*xSync)(sqlite3_file*, int flags); 739 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 740 int (*xLock)(sqlite3_file*, int); 741 int (*xUnlock)(sqlite3_file*, int); 742 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 743 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 744 int (*xSectorSize)(sqlite3_file*); 745 int (*xDeviceCharacteristics)(sqlite3_file*); 746 /* Methods above are valid for version 1 */ 747 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 748 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 749 void (*xShmBarrier)(sqlite3_file*); 750 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 751 /* Methods above are valid for version 2 */ 752 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 753 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 754 /* Methods above are valid for version 3 */ 755 /* Additional methods may be added in future releases */ 756}; 757 758/* 759** CAPI3REF: Standard File Control Opcodes 760** KEYWORDS: {file control opcodes} {file control opcode} 761** 762** These integer constants are opcodes for the xFileControl method 763** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 764** interface. 765** 766** <ul> 767** <li>[[SQLITE_FCNTL_LOCKSTATE]] 768** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 769** opcode causes the xFileControl method to write the current state of 770** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 771** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 772** into an integer that the pArg argument points to. This capability 773** is used during testing and is only available when the SQLITE_TEST 774** compile-time option is used. 775** 776** <li>[[SQLITE_FCNTL_SIZE_HINT]] 777** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 778** layer a hint of how large the database file will grow to be during the 779** current transaction. This hint is not guaranteed to be accurate but it 780** is often close. The underlying VFS might choose to preallocate database 781** file space based on this hint in order to help writes to the database 782** file run faster. 783** 784** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 785** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 786** extends and truncates the database file in chunks of a size specified 787** by the user. The fourth argument to [sqlite3_file_control()] should 788** point to an integer (type int) containing the new chunk-size to use 789** for the nominated database. Allocating database file space in large 790** chunks (say 1MB at a time), may reduce file-system fragmentation and 791** improve performance on some systems. 792** 793** <li>[[SQLITE_FCNTL_FILE_POINTER]] 794** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 795** to the [sqlite3_file] object associated with a particular database 796** connection. See the [sqlite3_file_control()] documentation for 797** additional information. 798** 799** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 800** No longer in use. 801** 802** <li>[[SQLITE_FCNTL_SYNC]] 803** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 804** sent to the VFS immediately before the xSync method is invoked on a 805** database file descriptor. Or, if the xSync method is not invoked 806** because the user has configured SQLite with 807** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 808** of the xSync method. In most cases, the pointer argument passed with 809** this file-control is NULL. However, if the database file is being synced 810** as part of a multi-database commit, the argument points to a nul-terminated 811** string containing the transactions master-journal file name. VFSes that 812** do not need this signal should silently ignore this opcode. Applications 813** should not call [sqlite3_file_control()] with this opcode as doing so may 814** disrupt the operation of the specialized VFSes that do require it. 815** 816** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 817** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 818** and sent to the VFS after a transaction has been committed immediately 819** but before the database is unlocked. VFSes that do not need this signal 820** should silently ignore this opcode. Applications should not call 821** [sqlite3_file_control()] with this opcode as doing so may disrupt the 822** operation of the specialized VFSes that do require it. 823** 824** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 825** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 826** retry counts and intervals for certain disk I/O operations for the 827** windows [VFS] in order to provide robustness in the presence of 828** anti-virus programs. By default, the windows VFS will retry file read, 829** file write, and file delete operations up to 10 times, with a delay 830** of 25 milliseconds before the first retry and with the delay increasing 831** by an additional 25 milliseconds with each subsequent retry. This 832** opcode allows these two values (10 retries and 25 milliseconds of delay) 833** to be adjusted. The values are changed for all database connections 834** within the same process. The argument is a pointer to an array of two 835** integers where the first integer i the new retry count and the second 836** integer is the delay. If either integer is negative, then the setting 837** is not changed but instead the prior value of that setting is written 838** into the array entry, allowing the current retry settings to be 839** interrogated. The zDbName parameter is ignored. 840** 841** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 842** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 843** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 844** write ahead log and shared memory files used for transaction control 845** are automatically deleted when the latest connection to the database 846** closes. Setting persistent WAL mode causes those files to persist after 847** close. Persisting the files is useful when other processes that do not 848** have write permission on the directory containing the database file want 849** to read the database file, as the WAL and shared memory files must exist 850** in order for the database to be readable. The fourth parameter to 851** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 852** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 853** WAL mode. If the integer is -1, then it is overwritten with the current 854** WAL persistence setting. 855** 856** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 857** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 858** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 859** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 860** xDeviceCharacteristics methods. The fourth parameter to 861** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 862** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 863** mode. If the integer is -1, then it is overwritten with the current 864** zero-damage mode setting. 865** 866** <li>[[SQLITE_FCNTL_OVERWRITE]] 867** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 868** a write transaction to indicate that, unless it is rolled back for some 869** reason, the entire database file will be overwritten by the current 870** transaction. This is used by VACUUM operations. 871** 872** <li>[[SQLITE_FCNTL_VFSNAME]] 873** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 874** all [VFSes] in the VFS stack. The names are of all VFS shims and the 875** final bottom-level VFS are written into memory obtained from 876** [sqlite3_malloc()] and the result is stored in the char* variable 877** that the fourth parameter of [sqlite3_file_control()] points to. 878** The caller is responsible for freeing the memory when done. As with 879** all file-control actions, there is no guarantee that this will actually 880** do anything. Callers should initialize the char* variable to a NULL 881** pointer in case this file-control is not implemented. This file-control 882** is intended for diagnostic use only. 883** 884** <li>[[SQLITE_FCNTL_PRAGMA]] 885** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 886** file control is sent to the open [sqlite3_file] object corresponding 887** to the database file to which the pragma statement refers. ^The argument 888** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 889** pointers to strings (char**) in which the second element of the array 890** is the name of the pragma and the third element is the argument to the 891** pragma or NULL if the pragma has no argument. ^The handler for an 892** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 893** of the char** argument point to a string obtained from [sqlite3_mprintf()] 894** or the equivalent and that string will become the result of the pragma or 895** the error message if the pragma fails. ^If the 896** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 897** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 898** file control returns [SQLITE_OK], then the parser assumes that the 899** VFS has handled the PRAGMA itself and the parser generates a no-op 900** prepared statement if result string is NULL, or that returns a copy 901** of the result string if the string is non-NULL. 902** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 903** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 904** that the VFS encountered an error while handling the [PRAGMA] and the 905** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 906** file control occurs at the beginning of pragma statement analysis and so 907** it is able to override built-in [PRAGMA] statements. 908** 909** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 910** ^The [SQLITE_FCNTL_BUSYHANDLER] 911** file-control may be invoked by SQLite on the database file handle 912** shortly after it is opened in order to provide a custom VFS with access 913** to the connections busy-handler callback. The argument is of type (void **) 914** - an array of two (void *) values. The first (void *) actually points 915** to a function of type (int (*)(void *)). In order to invoke the connections 916** busy-handler, this function should be invoked with the second (void *) in 917** the array as the only argument. If it returns non-zero, then the operation 918** should be retried. If it returns zero, the custom VFS should abandon the 919** current operation. 920** 921** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 922** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 923** to have SQLite generate a 924** temporary filename using the same algorithm that is followed to generate 925** temporary filenames for TEMP tables and other internal uses. The 926** argument should be a char** which will be filled with the filename 927** written into memory obtained from [sqlite3_malloc()]. The caller should 928** invoke [sqlite3_free()] on the result to avoid a memory leak. 929** 930** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 931** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 932** maximum number of bytes that will be used for memory-mapped I/O. 933** The argument is a pointer to a value of type sqlite3_int64 that 934** is an advisory maximum number of bytes in the file to memory map. The 935** pointer is overwritten with the old value. The limit is not changed if 936** the value originally pointed to is negative, and so the current limit 937** can be queried by passing in a pointer to a negative number. This 938** file-control is used internally to implement [PRAGMA mmap_size]. 939** 940** <li>[[SQLITE_FCNTL_TRACE]] 941** The [SQLITE_FCNTL_TRACE] file control provides advisory information 942** to the VFS about what the higher layers of the SQLite stack are doing. 943** This file control is used by some VFS activity tracing [shims]. 944** The argument is a zero-terminated string. Higher layers in the 945** SQLite stack may generate instances of this file control if 946** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 947** 948** <li>[[SQLITE_FCNTL_HAS_MOVED]] 949** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 950** pointer to an integer and it writes a boolean into that integer depending 951** on whether or not the file has been renamed, moved, or deleted since it 952** was first opened. 953** 954** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 955** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 956** opcode causes the xFileControl method to swap the file handle with the one 957** pointed to by the pArg argument. This capability is used during testing 958** and only needs to be supported when SQLITE_TEST is defined. 959** 960** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 961** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 962** be advantageous to block on the next WAL lock if the lock is not immediately 963** available. The WAL subsystem issues this signal during rare 964** circumstances in order to fix a problem with priority inversion. 965** Applications should <em>not</em> use this file-control. 966** 967** <li>[[SQLITE_FCNTL_ZIPVFS]] 968** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 969** VFS should return SQLITE_NOTFOUND for this opcode. 970** 971** <li>[[SQLITE_FCNTL_RBU]] 972** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 973** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 974** this opcode. 975** </ul> 976*/ 977#define SQLITE_FCNTL_LOCKSTATE 1 978#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 979#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 980#define SQLITE_FCNTL_LAST_ERRNO 4 981#define SQLITE_FCNTL_SIZE_HINT 5 982#define SQLITE_FCNTL_CHUNK_SIZE 6 983#define SQLITE_FCNTL_FILE_POINTER 7 984#define SQLITE_FCNTL_SYNC_OMITTED 8 985#define SQLITE_FCNTL_WIN32_AV_RETRY 9 986#define SQLITE_FCNTL_PERSIST_WAL 10 987#define SQLITE_FCNTL_OVERWRITE 11 988#define SQLITE_FCNTL_VFSNAME 12 989#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 990#define SQLITE_FCNTL_PRAGMA 14 991#define SQLITE_FCNTL_BUSYHANDLER 15 992#define SQLITE_FCNTL_TEMPFILENAME 16 993#define SQLITE_FCNTL_MMAP_SIZE 18 994#define SQLITE_FCNTL_TRACE 19 995#define SQLITE_FCNTL_HAS_MOVED 20 996#define SQLITE_FCNTL_SYNC 21 997#define SQLITE_FCNTL_COMMIT_PHASETWO 22 998#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 999#define SQLITE_FCNTL_WAL_BLOCK 24 1000#define SQLITE_FCNTL_ZIPVFS 25 1001#define SQLITE_FCNTL_RBU 26 1002 1003/* deprecated names */ 1004#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1005#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1006#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1007 1008 1009/* 1010** CAPI3REF: Mutex Handle 1011** 1012** The mutex module within SQLite defines [sqlite3_mutex] to be an 1013** abstract type for a mutex object. The SQLite core never looks 1014** at the internal representation of an [sqlite3_mutex]. It only 1015** deals with pointers to the [sqlite3_mutex] object. 1016** 1017** Mutexes are created using [sqlite3_mutex_alloc()]. 1018*/ 1019typedef struct sqlite3_mutex sqlite3_mutex; 1020 1021/* 1022** CAPI3REF: OS Interface Object 1023** 1024** An instance of the sqlite3_vfs object defines the interface between 1025** the SQLite core and the underlying operating system. The "vfs" 1026** in the name of the object stands for "virtual file system". See 1027** the [VFS | VFS documentation] for further information. 1028** 1029** The value of the iVersion field is initially 1 but may be larger in 1030** future versions of SQLite. Additional fields may be appended to this 1031** object when the iVersion value is increased. Note that the structure 1032** of the sqlite3_vfs object changes in the transaction between 1033** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1034** modified. 1035** 1036** The szOsFile field is the size of the subclassed [sqlite3_file] 1037** structure used by this VFS. mxPathname is the maximum length of 1038** a pathname in this VFS. 1039** 1040** Registered sqlite3_vfs objects are kept on a linked list formed by 1041** the pNext pointer. The [sqlite3_vfs_register()] 1042** and [sqlite3_vfs_unregister()] interfaces manage this list 1043** in a thread-safe way. The [sqlite3_vfs_find()] interface 1044** searches the list. Neither the application code nor the VFS 1045** implementation should use the pNext pointer. 1046** 1047** The pNext field is the only field in the sqlite3_vfs 1048** structure that SQLite will ever modify. SQLite will only access 1049** or modify this field while holding a particular static mutex. 1050** The application should never modify anything within the sqlite3_vfs 1051** object once the object has been registered. 1052** 1053** The zName field holds the name of the VFS module. The name must 1054** be unique across all VFS modules. 1055** 1056** [[sqlite3_vfs.xOpen]] 1057** ^SQLite guarantees that the zFilename parameter to xOpen 1058** is either a NULL pointer or string obtained 1059** from xFullPathname() with an optional suffix added. 1060** ^If a suffix is added to the zFilename parameter, it will 1061** consist of a single "-" character followed by no more than 1062** 11 alphanumeric and/or "-" characters. 1063** ^SQLite further guarantees that 1064** the string will be valid and unchanged until xClose() is 1065** called. Because of the previous sentence, 1066** the [sqlite3_file] can safely store a pointer to the 1067** filename if it needs to remember the filename for some reason. 1068** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1069** must invent its own temporary name for the file. ^Whenever the 1070** xFilename parameter is NULL it will also be the case that the 1071** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1072** 1073** The flags argument to xOpen() includes all bits set in 1074** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1075** or [sqlite3_open16()] is used, then flags includes at least 1076** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1077** If xOpen() opens a file read-only then it sets *pOutFlags to 1078** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1079** 1080** ^(SQLite will also add one of the following flags to the xOpen() 1081** call, depending on the object being opened: 1082** 1083** <ul> 1084** <li> [SQLITE_OPEN_MAIN_DB] 1085** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1086** <li> [SQLITE_OPEN_TEMP_DB] 1087** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1088** <li> [SQLITE_OPEN_TRANSIENT_DB] 1089** <li> [SQLITE_OPEN_SUBJOURNAL] 1090** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1091** <li> [SQLITE_OPEN_WAL] 1092** </ul>)^ 1093** 1094** The file I/O implementation can use the object type flags to 1095** change the way it deals with files. For example, an application 1096** that does not care about crash recovery or rollback might make 1097** the open of a journal file a no-op. Writes to this journal would 1098** also be no-ops, and any attempt to read the journal would return 1099** SQLITE_IOERR. Or the implementation might recognize that a database 1100** file will be doing page-aligned sector reads and writes in a random 1101** order and set up its I/O subsystem accordingly. 1102** 1103** SQLite might also add one of the following flags to the xOpen method: 1104** 1105** <ul> 1106** <li> [SQLITE_OPEN_DELETEONCLOSE] 1107** <li> [SQLITE_OPEN_EXCLUSIVE] 1108** </ul> 1109** 1110** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1111** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1112** will be set for TEMP databases and their journals, transient 1113** databases, and subjournals. 1114** 1115** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1116** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1117** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1118** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1119** SQLITE_OPEN_CREATE, is used to indicate that file should always 1120** be created, and that it is an error if it already exists. 1121** It is <i>not</i> used to indicate the file should be opened 1122** for exclusive access. 1123** 1124** ^At least szOsFile bytes of memory are allocated by SQLite 1125** to hold the [sqlite3_file] structure passed as the third 1126** argument to xOpen. The xOpen method does not have to 1127** allocate the structure; it should just fill it in. Note that 1128** the xOpen method must set the sqlite3_file.pMethods to either 1129** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1130** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1131** element will be valid after xOpen returns regardless of the success 1132** or failure of the xOpen call. 1133** 1134** [[sqlite3_vfs.xAccess]] 1135** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1136** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1137** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1138** to test whether a file is at least readable. The file can be a 1139** directory. 1140** 1141** ^SQLite will always allocate at least mxPathname+1 bytes for the 1142** output buffer xFullPathname. The exact size of the output buffer 1143** is also passed as a parameter to both methods. If the output buffer 1144** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1145** handled as a fatal error by SQLite, vfs implementations should endeavor 1146** to prevent this by setting mxPathname to a sufficiently large value. 1147** 1148** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1149** interfaces are not strictly a part of the filesystem, but they are 1150** included in the VFS structure for completeness. 1151** The xRandomness() function attempts to return nBytes bytes 1152** of good-quality randomness into zOut. The return value is 1153** the actual number of bytes of randomness obtained. 1154** The xSleep() method causes the calling thread to sleep for at 1155** least the number of microseconds given. ^The xCurrentTime() 1156** method returns a Julian Day Number for the current date and time as 1157** a floating point value. 1158** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1159** Day Number multiplied by 86400000 (the number of milliseconds in 1160** a 24-hour day). 1161** ^SQLite will use the xCurrentTimeInt64() method to get the current 1162** date and time if that method is available (if iVersion is 2 or 1163** greater and the function pointer is not NULL) and will fall back 1164** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1165** 1166** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1167** are not used by the SQLite core. These optional interfaces are provided 1168** by some VFSes to facilitate testing of the VFS code. By overriding 1169** system calls with functions under its control, a test program can 1170** simulate faults and error conditions that would otherwise be difficult 1171** or impossible to induce. The set of system calls that can be overridden 1172** varies from one VFS to another, and from one version of the same VFS to the 1173** next. Applications that use these interfaces must be prepared for any 1174** or all of these interfaces to be NULL or for their behavior to change 1175** from one release to the next. Applications must not attempt to access 1176** any of these methods if the iVersion of the VFS is less than 3. 1177*/ 1178typedef struct sqlite3_vfs sqlite3_vfs; 1179typedef void (*sqlite3_syscall_ptr)(void); 1180struct sqlite3_vfs { 1181 int iVersion; /* Structure version number (currently 3) */ 1182 int szOsFile; /* Size of subclassed sqlite3_file */ 1183 int mxPathname; /* Maximum file pathname length */ 1184 sqlite3_vfs *pNext; /* Next registered VFS */ 1185 const char *zName; /* Name of this virtual file system */ 1186 void *pAppData; /* Pointer to application-specific data */ 1187 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1188 int flags, int *pOutFlags); 1189 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1190 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1191 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1192 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1193 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1194 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1195 void (*xDlClose)(sqlite3_vfs*, void*); 1196 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1197 int (*xSleep)(sqlite3_vfs*, int microseconds); 1198 int (*xCurrentTime)(sqlite3_vfs*, double*); 1199 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1200 /* 1201 ** The methods above are in version 1 of the sqlite_vfs object 1202 ** definition. Those that follow are added in version 2 or later 1203 */ 1204 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1205 /* 1206 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1207 ** Those below are for version 3 and greater. 1208 */ 1209 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1210 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1211 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1212 /* 1213 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1214 ** New fields may be appended in figure versions. The iVersion 1215 ** value will increment whenever this happens. 1216 */ 1217}; 1218 1219/* 1220** CAPI3REF: Flags for the xAccess VFS method 1221** 1222** These integer constants can be used as the third parameter to 1223** the xAccess method of an [sqlite3_vfs] object. They determine 1224** what kind of permissions the xAccess method is looking for. 1225** With SQLITE_ACCESS_EXISTS, the xAccess method 1226** simply checks whether the file exists. 1227** With SQLITE_ACCESS_READWRITE, the xAccess method 1228** checks whether the named directory is both readable and writable 1229** (in other words, if files can be added, removed, and renamed within 1230** the directory). 1231** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1232** [temp_store_directory pragma], though this could change in a future 1233** release of SQLite. 1234** With SQLITE_ACCESS_READ, the xAccess method 1235** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1236** currently unused, though it might be used in a future release of 1237** SQLite. 1238*/ 1239#define SQLITE_ACCESS_EXISTS 0 1240#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1241#define SQLITE_ACCESS_READ 2 /* Unused */ 1242 1243/* 1244** CAPI3REF: Flags for the xShmLock VFS method 1245** 1246** These integer constants define the various locking operations 1247** allowed by the xShmLock method of [sqlite3_io_methods]. The 1248** following are the only legal combinations of flags to the 1249** xShmLock method: 1250** 1251** <ul> 1252** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1253** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1254** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1255** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1256** </ul> 1257** 1258** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1259** was given on the corresponding lock. 1260** 1261** The xShmLock method can transition between unlocked and SHARED or 1262** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1263** and EXCLUSIVE. 1264*/ 1265#define SQLITE_SHM_UNLOCK 1 1266#define SQLITE_SHM_LOCK 2 1267#define SQLITE_SHM_SHARED 4 1268#define SQLITE_SHM_EXCLUSIVE 8 1269 1270/* 1271** CAPI3REF: Maximum xShmLock index 1272** 1273** The xShmLock method on [sqlite3_io_methods] may use values 1274** between 0 and this upper bound as its "offset" argument. 1275** The SQLite core will never attempt to acquire or release a 1276** lock outside of this range 1277*/ 1278#define SQLITE_SHM_NLOCK 8 1279 1280 1281/* 1282** CAPI3REF: Initialize The SQLite Library 1283** 1284** ^The sqlite3_initialize() routine initializes the 1285** SQLite library. ^The sqlite3_shutdown() routine 1286** deallocates any resources that were allocated by sqlite3_initialize(). 1287** These routines are designed to aid in process initialization and 1288** shutdown on embedded systems. Workstation applications using 1289** SQLite normally do not need to invoke either of these routines. 1290** 1291** A call to sqlite3_initialize() is an "effective" call if it is 1292** the first time sqlite3_initialize() is invoked during the lifetime of 1293** the process, or if it is the first time sqlite3_initialize() is invoked 1294** following a call to sqlite3_shutdown(). ^(Only an effective call 1295** of sqlite3_initialize() does any initialization. All other calls 1296** are harmless no-ops.)^ 1297** 1298** A call to sqlite3_shutdown() is an "effective" call if it is the first 1299** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1300** an effective call to sqlite3_shutdown() does any deinitialization. 1301** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1302** 1303** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1304** is not. The sqlite3_shutdown() interface must only be called from a 1305** single thread. All open [database connections] must be closed and all 1306** other SQLite resources must be deallocated prior to invoking 1307** sqlite3_shutdown(). 1308** 1309** Among other things, ^sqlite3_initialize() will invoke 1310** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1311** will invoke sqlite3_os_end(). 1312** 1313** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1314** ^If for some reason, sqlite3_initialize() is unable to initialize 1315** the library (perhaps it is unable to allocate a needed resource such 1316** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1317** 1318** ^The sqlite3_initialize() routine is called internally by many other 1319** SQLite interfaces so that an application usually does not need to 1320** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1321** calls sqlite3_initialize() so the SQLite library will be automatically 1322** initialized when [sqlite3_open()] is called if it has not be initialized 1323** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1324** compile-time option, then the automatic calls to sqlite3_initialize() 1325** are omitted and the application must call sqlite3_initialize() directly 1326** prior to using any other SQLite interface. For maximum portability, 1327** it is recommended that applications always invoke sqlite3_initialize() 1328** directly prior to using any other SQLite interface. Future releases 1329** of SQLite may require this. In other words, the behavior exhibited 1330** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1331** default behavior in some future release of SQLite. 1332** 1333** The sqlite3_os_init() routine does operating-system specific 1334** initialization of the SQLite library. The sqlite3_os_end() 1335** routine undoes the effect of sqlite3_os_init(). Typical tasks 1336** performed by these routines include allocation or deallocation 1337** of static resources, initialization of global variables, 1338** setting up a default [sqlite3_vfs] module, or setting up 1339** a default configuration using [sqlite3_config()]. 1340** 1341** The application should never invoke either sqlite3_os_init() 1342** or sqlite3_os_end() directly. The application should only invoke 1343** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1344** interface is called automatically by sqlite3_initialize() and 1345** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1346** implementations for sqlite3_os_init() and sqlite3_os_end() 1347** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1348** When [custom builds | built for other platforms] 1349** (using the [SQLITE_OS_OTHER=1] compile-time 1350** option) the application must supply a suitable implementation for 1351** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1352** implementation of sqlite3_os_init() or sqlite3_os_end() 1353** must return [SQLITE_OK] on success and some other [error code] upon 1354** failure. 1355*/ 1356SQLITE_API int SQLITE_STDCALL sqlite3_initialize(void); 1357SQLITE_API int SQLITE_STDCALL sqlite3_shutdown(void); 1358SQLITE_API int SQLITE_STDCALL sqlite3_os_init(void); 1359SQLITE_API int SQLITE_STDCALL sqlite3_os_end(void); 1360 1361/* 1362** CAPI3REF: Configuring The SQLite Library 1363** 1364** The sqlite3_config() interface is used to make global configuration 1365** changes to SQLite in order to tune SQLite to the specific needs of 1366** the application. The default configuration is recommended for most 1367** applications and so this routine is usually not necessary. It is 1368** provided to support rare applications with unusual needs. 1369** 1370** <b>The sqlite3_config() interface is not threadsafe. The application 1371** must ensure that no other SQLite interfaces are invoked by other 1372** threads while sqlite3_config() is running.</b> 1373** 1374** The sqlite3_config() interface 1375** may only be invoked prior to library initialization using 1376** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1377** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1378** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1379** Note, however, that ^sqlite3_config() can be called as part of the 1380** implementation of an application-defined [sqlite3_os_init()]. 1381** 1382** The first argument to sqlite3_config() is an integer 1383** [configuration option] that determines 1384** what property of SQLite is to be configured. Subsequent arguments 1385** vary depending on the [configuration option] 1386** in the first argument. 1387** 1388** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1389** ^If the option is unknown or SQLite is unable to set the option 1390** then this routine returns a non-zero [error code]. 1391*/ 1392SQLITE_API int SQLITE_CDECL sqlite3_config(int, ...); 1393 1394/* 1395** CAPI3REF: Configure database connections 1396** METHOD: sqlite3 1397** 1398** The sqlite3_db_config() interface is used to make configuration 1399** changes to a [database connection]. The interface is similar to 1400** [sqlite3_config()] except that the changes apply to a single 1401** [database connection] (specified in the first argument). 1402** 1403** The second argument to sqlite3_db_config(D,V,...) is the 1404** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1405** that indicates what aspect of the [database connection] is being configured. 1406** Subsequent arguments vary depending on the configuration verb. 1407** 1408** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1409** the call is considered successful. 1410*/ 1411SQLITE_API int SQLITE_CDECL sqlite3_db_config(sqlite3*, int op, ...); 1412 1413/* 1414** CAPI3REF: Memory Allocation Routines 1415** 1416** An instance of this object defines the interface between SQLite 1417** and low-level memory allocation routines. 1418** 1419** This object is used in only one place in the SQLite interface. 1420** A pointer to an instance of this object is the argument to 1421** [sqlite3_config()] when the configuration option is 1422** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1423** By creating an instance of this object 1424** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1425** during configuration, an application can specify an alternative 1426** memory allocation subsystem for SQLite to use for all of its 1427** dynamic memory needs. 1428** 1429** Note that SQLite comes with several [built-in memory allocators] 1430** that are perfectly adequate for the overwhelming majority of applications 1431** and that this object is only useful to a tiny minority of applications 1432** with specialized memory allocation requirements. This object is 1433** also used during testing of SQLite in order to specify an alternative 1434** memory allocator that simulates memory out-of-memory conditions in 1435** order to verify that SQLite recovers gracefully from such 1436** conditions. 1437** 1438** The xMalloc, xRealloc, and xFree methods must work like the 1439** malloc(), realloc() and free() functions from the standard C library. 1440** ^SQLite guarantees that the second argument to 1441** xRealloc is always a value returned by a prior call to xRoundup. 1442** 1443** xSize should return the allocated size of a memory allocation 1444** previously obtained from xMalloc or xRealloc. The allocated size 1445** is always at least as big as the requested size but may be larger. 1446** 1447** The xRoundup method returns what would be the allocated size of 1448** a memory allocation given a particular requested size. Most memory 1449** allocators round up memory allocations at least to the next multiple 1450** of 8. Some allocators round up to a larger multiple or to a power of 2. 1451** Every memory allocation request coming in through [sqlite3_malloc()] 1452** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1453** that causes the corresponding memory allocation to fail. 1454** 1455** The xInit method initializes the memory allocator. For example, 1456** it might allocate any require mutexes or initialize internal data 1457** structures. The xShutdown method is invoked (indirectly) by 1458** [sqlite3_shutdown()] and should deallocate any resources acquired 1459** by xInit. The pAppData pointer is used as the only parameter to 1460** xInit and xShutdown. 1461** 1462** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1463** the xInit method, so the xInit method need not be threadsafe. The 1464** xShutdown method is only called from [sqlite3_shutdown()] so it does 1465** not need to be threadsafe either. For all other methods, SQLite 1466** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1467** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1468** it is by default) and so the methods are automatically serialized. 1469** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1470** methods must be threadsafe or else make their own arrangements for 1471** serialization. 1472** 1473** SQLite will never invoke xInit() more than once without an intervening 1474** call to xShutdown(). 1475*/ 1476typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1477struct sqlite3_mem_methods { 1478 void *(*xMalloc)(int); /* Memory allocation function */ 1479 void (*xFree)(void*); /* Free a prior allocation */ 1480 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1481 int (*xSize)(void*); /* Return the size of an allocation */ 1482 int (*xRoundup)(int); /* Round up request size to allocation size */ 1483 int (*xInit)(void*); /* Initialize the memory allocator */ 1484 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1485 void *pAppData; /* Argument to xInit() and xShutdown() */ 1486}; 1487 1488/* 1489** CAPI3REF: Configuration Options 1490** KEYWORDS: {configuration option} 1491** 1492** These constants are the available integer configuration options that 1493** can be passed as the first argument to the [sqlite3_config()] interface. 1494** 1495** New configuration options may be added in future releases of SQLite. 1496** Existing configuration options might be discontinued. Applications 1497** should check the return code from [sqlite3_config()] to make sure that 1498** the call worked. The [sqlite3_config()] interface will return a 1499** non-zero [error code] if a discontinued or unsupported configuration option 1500** is invoked. 1501** 1502** <dl> 1503** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1504** <dd>There are no arguments to this option. ^This option sets the 1505** [threading mode] to Single-thread. In other words, it disables 1506** all mutexing and puts SQLite into a mode where it can only be used 1507** by a single thread. ^If SQLite is compiled with 1508** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1509** it is not possible to change the [threading mode] from its default 1510** value of Single-thread and so [sqlite3_config()] will return 1511** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1512** configuration option.</dd> 1513** 1514** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1515** <dd>There are no arguments to this option. ^This option sets the 1516** [threading mode] to Multi-thread. In other words, it disables 1517** mutexing on [database connection] and [prepared statement] objects. 1518** The application is responsible for serializing access to 1519** [database connections] and [prepared statements]. But other mutexes 1520** are enabled so that SQLite will be safe to use in a multi-threaded 1521** environment as long as no two threads attempt to use the same 1522** [database connection] at the same time. ^If SQLite is compiled with 1523** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1524** it is not possible to set the Multi-thread [threading mode] and 1525** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1526** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1527** 1528** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1529** <dd>There are no arguments to this option. ^This option sets the 1530** [threading mode] to Serialized. In other words, this option enables 1531** all mutexes including the recursive 1532** mutexes on [database connection] and [prepared statement] objects. 1533** In this mode (which is the default when SQLite is compiled with 1534** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1535** to [database connections] and [prepared statements] so that the 1536** application is free to use the same [database connection] or the 1537** same [prepared statement] in different threads at the same time. 1538** ^If SQLite is compiled with 1539** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1540** it is not possible to set the Serialized [threading mode] and 1541** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1542** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1543** 1544** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1545** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1546** a pointer to an instance of the [sqlite3_mem_methods] structure. 1547** The argument specifies 1548** alternative low-level memory allocation routines to be used in place of 1549** the memory allocation routines built into SQLite.)^ ^SQLite makes 1550** its own private copy of the content of the [sqlite3_mem_methods] structure 1551** before the [sqlite3_config()] call returns.</dd> 1552** 1553** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1554** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1555** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1556** The [sqlite3_mem_methods] 1557** structure is filled with the currently defined memory allocation routines.)^ 1558** This option can be used to overload the default memory allocation 1559** routines with a wrapper that simulations memory allocation failure or 1560** tracks memory usage, for example. </dd> 1561** 1562** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1563** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1564** interpreted as a boolean, which enables or disables the collection of 1565** memory allocation statistics. ^(When memory allocation statistics are 1566** disabled, the following SQLite interfaces become non-operational: 1567** <ul> 1568** <li> [sqlite3_memory_used()] 1569** <li> [sqlite3_memory_highwater()] 1570** <li> [sqlite3_soft_heap_limit64()] 1571** <li> [sqlite3_status64()] 1572** </ul>)^ 1573** ^Memory allocation statistics are enabled by default unless SQLite is 1574** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1575** allocation statistics are disabled by default. 1576** </dd> 1577** 1578** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1579** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer 1580** that SQLite can use for scratch memory. ^(There are three arguments 1581** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte 1582** aligned memory buffer from which the scratch allocations will be 1583** drawn, the size of each scratch allocation (sz), 1584** and the maximum number of scratch allocations (N).)^ 1585** The first argument must be a pointer to an 8-byte aligned buffer 1586** of at least sz*N bytes of memory. 1587** ^SQLite will not use more than one scratch buffers per thread. 1588** ^SQLite will never request a scratch buffer that is more than 6 1589** times the database page size. 1590** ^If SQLite needs needs additional 1591** scratch memory beyond what is provided by this configuration option, then 1592** [sqlite3_malloc()] will be used to obtain the memory needed.<p> 1593** ^When the application provides any amount of scratch memory using 1594** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large 1595** [sqlite3_malloc|heap allocations]. 1596** This can help [Robson proof|prevent memory allocation failures] due to heap 1597** fragmentation in low-memory embedded systems. 1598** </dd> 1599** 1600** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1601** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer 1602** that SQLite can use for the database page cache with the default page 1603** cache implementation. 1604** This configuration should not be used if an application-define page 1605** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2] 1606** configuration option. 1607** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1608** 8-byte aligned 1609** memory, the size of each page buffer (sz), and the number of pages (N). 1610** The sz argument should be the size of the largest database page 1611** (a power of two between 512 and 65536) plus some extra bytes for each 1612** page header. ^The number of extra bytes needed by the page header 1613** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option 1614** to [sqlite3_config()]. 1615** ^It is harmless, apart from the wasted memory, 1616** for the sz parameter to be larger than necessary. The first 1617** argument should pointer to an 8-byte aligned block of memory that 1618** is at least sz*N bytes of memory, otherwise subsequent behavior is 1619** undefined. 1620** ^SQLite will use the memory provided by the first argument to satisfy its 1621** memory needs for the first N pages that it adds to cache. ^If additional 1622** page cache memory is needed beyond what is provided by this option, then 1623** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd> 1624** 1625** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1626** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1627** that SQLite will use for all of its dynamic memory allocation needs 1628** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and 1629** [SQLITE_CONFIG_PAGECACHE]. 1630** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1631** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1632** [SQLITE_ERROR] if invoked otherwise. 1633** ^There are three arguments to SQLITE_CONFIG_HEAP: 1634** An 8-byte aligned pointer to the memory, 1635** the number of bytes in the memory buffer, and the minimum allocation size. 1636** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1637** to using its default memory allocator (the system malloc() implementation), 1638** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1639** memory pointer is not NULL then the alternative memory 1640** allocator is engaged to handle all of SQLites memory allocation needs. 1641** The first pointer (the memory pointer) must be aligned to an 8-byte 1642** boundary or subsequent behavior of SQLite will be undefined. 1643** The minimum allocation size is capped at 2**12. Reasonable values 1644** for the minimum allocation size are 2**5 through 2**8.</dd> 1645** 1646** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1647** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1648** pointer to an instance of the [sqlite3_mutex_methods] structure. 1649** The argument specifies alternative low-level mutex routines to be used 1650** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1651** the content of the [sqlite3_mutex_methods] structure before the call to 1652** [sqlite3_config()] returns. ^If SQLite is compiled with 1653** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1654** the entire mutexing subsystem is omitted from the build and hence calls to 1655** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1656** return [SQLITE_ERROR].</dd> 1657** 1658** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1659** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1660** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1661** [sqlite3_mutex_methods] 1662** structure is filled with the currently defined mutex routines.)^ 1663** This option can be used to overload the default mutex allocation 1664** routines with a wrapper used to track mutex usage for performance 1665** profiling or testing, for example. ^If SQLite is compiled with 1666** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1667** the entire mutexing subsystem is omitted from the build and hence calls to 1668** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1669** return [SQLITE_ERROR].</dd> 1670** 1671** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1672** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1673** the default size of lookaside memory on each [database connection]. 1674** The first argument is the 1675** size of each lookaside buffer slot and the second is the number of 1676** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1677** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1678** option to [sqlite3_db_config()] can be used to change the lookaside 1679** configuration on individual connections.)^ </dd> 1680** 1681** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1682** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1683** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1684** the interface to a custom page cache implementation.)^ 1685** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1686** 1687** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1688** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1689** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1690** the current page cache implementation into that object.)^ </dd> 1691** 1692** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1693** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1694** global [error log]. 1695** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1696** function with a call signature of void(*)(void*,int,const char*), 1697** and a pointer to void. ^If the function pointer is not NULL, it is 1698** invoked by [sqlite3_log()] to process each logging event. ^If the 1699** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1700** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1701** passed through as the first parameter to the application-defined logger 1702** function whenever that function is invoked. ^The second parameter to 1703** the logger function is a copy of the first parameter to the corresponding 1704** [sqlite3_log()] call and is intended to be a [result code] or an 1705** [extended result code]. ^The third parameter passed to the logger is 1706** log message after formatting via [sqlite3_snprintf()]. 1707** The SQLite logging interface is not reentrant; the logger function 1708** supplied by the application must not invoke any SQLite interface. 1709** In a multi-threaded application, the application-defined logger 1710** function must be threadsafe. </dd> 1711** 1712** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1713** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1714** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1715** then URI handling is globally disabled.)^ ^If URI handling is globally 1716** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1717** [sqlite3_open16()] or 1718** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1719** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1720** connection is opened. ^If it is globally disabled, filenames are 1721** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1722** database connection is opened. ^(By default, URI handling is globally 1723** disabled. The default value may be changed by compiling with the 1724** [SQLITE_USE_URI] symbol defined.)^ 1725** 1726** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1727** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1728** argument which is interpreted as a boolean in order to enable or disable 1729** the use of covering indices for full table scans in the query optimizer. 1730** ^The default setting is determined 1731** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1732** if that compile-time option is omitted. 1733** The ability to disable the use of covering indices for full table scans 1734** is because some incorrectly coded legacy applications might malfunction 1735** when the optimization is enabled. Providing the ability to 1736** disable the optimization allows the older, buggy application code to work 1737** without change even with newer versions of SQLite. 1738** 1739** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1740** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1741** <dd> These options are obsolete and should not be used by new code. 1742** They are retained for backwards compatibility but are now no-ops. 1743** </dd> 1744** 1745** [[SQLITE_CONFIG_SQLLOG]] 1746** <dt>SQLITE_CONFIG_SQLLOG 1747** <dd>This option is only available if sqlite is compiled with the 1748** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1749** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1750** The second should be of type (void*). The callback is invoked by the library 1751** in three separate circumstances, identified by the value passed as the 1752** fourth parameter. If the fourth parameter is 0, then the database connection 1753** passed as the second argument has just been opened. The third argument 1754** points to a buffer containing the name of the main database file. If the 1755** fourth parameter is 1, then the SQL statement that the third parameter 1756** points to has just been executed. Or, if the fourth parameter is 2, then 1757** the connection being passed as the second parameter is being closed. The 1758** third parameter is passed NULL In this case. An example of using this 1759** configuration option can be seen in the "test_sqllog.c" source file in 1760** the canonical SQLite source tree.</dd> 1761** 1762** [[SQLITE_CONFIG_MMAP_SIZE]] 1763** <dt>SQLITE_CONFIG_MMAP_SIZE 1764** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1765** that are the default mmap size limit (the default setting for 1766** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1767** ^The default setting can be overridden by each database connection using 1768** either the [PRAGMA mmap_size] command, or by using the 1769** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1770** will be silently truncated if necessary so that it does not exceed the 1771** compile-time maximum mmap size set by the 1772** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1773** ^If either argument to this option is negative, then that argument is 1774** changed to its compile-time default. 1775** 1776** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1777** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1778** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1779** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1780** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1781** that specifies the maximum size of the created heap. 1782** 1783** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1784** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1785** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1786** is a pointer to an integer and writes into that integer the number of extra 1787** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1788** The amount of extra space required can change depending on the compiler, 1789** target platform, and SQLite version. 1790** 1791** [[SQLITE_CONFIG_PMASZ]] 1792** <dt>SQLITE_CONFIG_PMASZ 1793** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1794** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1795** sorter to that integer. The default minimum PMA Size is set by the 1796** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1797** to help with sort operations when multithreaded sorting 1798** is enabled (using the [PRAGMA threads] command) and the amount of content 1799** to be sorted exceeds the page size times the minimum of the 1800** [PRAGMA cache_size] setting and this value. 1801** </dl> 1802*/ 1803#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1804#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1805#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1806#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1807#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1808#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1809#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1810#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1811#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1812#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1813#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1814/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1815#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1816#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1817#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1818#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1819#define SQLITE_CONFIG_URI 17 /* int */ 1820#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1821#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1822#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1823#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1824#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1825#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1826#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1827#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1828 1829/* 1830** CAPI3REF: Database Connection Configuration Options 1831** 1832** These constants are the available integer configuration options that 1833** can be passed as the second argument to the [sqlite3_db_config()] interface. 1834** 1835** New configuration options may be added in future releases of SQLite. 1836** Existing configuration options might be discontinued. Applications 1837** should check the return code from [sqlite3_db_config()] to make sure that 1838** the call worked. ^The [sqlite3_db_config()] interface will return a 1839** non-zero [error code] if a discontinued or unsupported configuration option 1840** is invoked. 1841** 1842** <dl> 1843** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1844** <dd> ^This option takes three additional arguments that determine the 1845** [lookaside memory allocator] configuration for the [database connection]. 1846** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1847** pointer to a memory buffer to use for lookaside memory. 1848** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1849** may be NULL in which case SQLite will allocate the 1850** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1851** size of each lookaside buffer slot. ^The third argument is the number of 1852** slots. The size of the buffer in the first argument must be greater than 1853** or equal to the product of the second and third arguments. The buffer 1854** must be aligned to an 8-byte boundary. ^If the second argument to 1855** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1856** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1857** configuration for a database connection can only be changed when that 1858** connection is not currently using lookaside memory, or in other words 1859** when the "current value" returned by 1860** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1861** Any attempt to change the lookaside memory configuration when lookaside 1862** memory is in use leaves the configuration unchanged and returns 1863** [SQLITE_BUSY].)^</dd> 1864** 1865** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1866** <dd> ^This option is used to enable or disable the enforcement of 1867** [foreign key constraints]. There should be two additional arguments. 1868** The first argument is an integer which is 0 to disable FK enforcement, 1869** positive to enable FK enforcement or negative to leave FK enforcement 1870** unchanged. The second parameter is a pointer to an integer into which 1871** is written 0 or 1 to indicate whether FK enforcement is off or on 1872** following this call. The second parameter may be a NULL pointer, in 1873** which case the FK enforcement setting is not reported back. </dd> 1874** 1875** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1876** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1877** There should be two additional arguments. 1878** The first argument is an integer which is 0 to disable triggers, 1879** positive to enable triggers or negative to leave the setting unchanged. 1880** The second parameter is a pointer to an integer into which 1881** is written 0 or 1 to indicate whether triggers are disabled or enabled 1882** following this call. The second parameter may be a NULL pointer, in 1883** which case the trigger setting is not reported back. </dd> 1884** 1885** </dl> 1886*/ 1887#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1888#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1889#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1890 1891 1892/* 1893** CAPI3REF: Enable Or Disable Extended Result Codes 1894** METHOD: sqlite3 1895** 1896** ^The sqlite3_extended_result_codes() routine enables or disables the 1897** [extended result codes] feature of SQLite. ^The extended result 1898** codes are disabled by default for historical compatibility. 1899*/ 1900SQLITE_API int SQLITE_STDCALL sqlite3_extended_result_codes(sqlite3*, int onoff); 1901 1902/* 1903** CAPI3REF: Last Insert Rowid 1904** METHOD: sqlite3 1905** 1906** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 1907** has a unique 64-bit signed 1908** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1909** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1910** names are not also used by explicitly declared columns. ^If 1911** the table has a column of type [INTEGER PRIMARY KEY] then that column 1912** is another alias for the rowid. 1913** 1914** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the 1915** most recent successful [INSERT] into a rowid table or [virtual table] 1916** on database connection D. 1917** ^Inserts into [WITHOUT ROWID] tables are not recorded. 1918** ^If no successful [INSERT]s into rowid tables 1919** have ever occurred on the database connection D, 1920** then sqlite3_last_insert_rowid(D) returns zero. 1921** 1922** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1923** method, then this routine will return the [rowid] of the inserted 1924** row as long as the trigger or virtual table method is running. 1925** But once the trigger or virtual table method ends, the value returned 1926** by this routine reverts to what it was before the trigger or virtual 1927** table method began.)^ 1928** 1929** ^An [INSERT] that fails due to a constraint violation is not a 1930** successful [INSERT] and does not change the value returned by this 1931** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1932** and INSERT OR ABORT make no changes to the return value of this 1933** routine when their insertion fails. ^(When INSERT OR REPLACE 1934** encounters a constraint violation, it does not fail. The 1935** INSERT continues to completion after deleting rows that caused 1936** the constraint problem so INSERT OR REPLACE will always change 1937** the return value of this interface.)^ 1938** 1939** ^For the purposes of this routine, an [INSERT] is considered to 1940** be successful even if it is subsequently rolled back. 1941** 1942** This function is accessible to SQL statements via the 1943** [last_insert_rowid() SQL function]. 1944** 1945** If a separate thread performs a new [INSERT] on the same 1946** database connection while the [sqlite3_last_insert_rowid()] 1947** function is running and thus changes the last insert [rowid], 1948** then the value returned by [sqlite3_last_insert_rowid()] is 1949** unpredictable and might not equal either the old or the new 1950** last insert [rowid]. 1951*/ 1952SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_last_insert_rowid(sqlite3*); 1953 1954/* 1955** CAPI3REF: Count The Number Of Rows Modified 1956** METHOD: sqlite3 1957** 1958** ^This function returns the number of rows modified, inserted or 1959** deleted by the most recently completed INSERT, UPDATE or DELETE 1960** statement on the database connection specified by the only parameter. 1961** ^Executing any other type of SQL statement does not modify the value 1962** returned by this function. 1963** 1964** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 1965** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 1966** [foreign key actions] or [REPLACE] constraint resolution are not counted. 1967** 1968** Changes to a view that are intercepted by 1969** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 1970** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 1971** DELETE statement run on a view is always zero. Only changes made to real 1972** tables are counted. 1973** 1974** Things are more complicated if the sqlite3_changes() function is 1975** executed while a trigger program is running. This may happen if the 1976** program uses the [changes() SQL function], or if some other callback 1977** function invokes sqlite3_changes() directly. Essentially: 1978** 1979** <ul> 1980** <li> ^(Before entering a trigger program the value returned by 1981** sqlite3_changes() function is saved. After the trigger program 1982** has finished, the original value is restored.)^ 1983** 1984** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 1985** statement sets the value returned by sqlite3_changes() 1986** upon completion as normal. Of course, this value will not include 1987** any changes performed by sub-triggers, as the sqlite3_changes() 1988** value will be saved and restored after each sub-trigger has run.)^ 1989** </ul> 1990** 1991** ^This means that if the changes() SQL function (or similar) is used 1992** by the first INSERT, UPDATE or DELETE statement within a trigger, it 1993** returns the value as set when the calling statement began executing. 1994** ^If it is used by the second or subsequent such statement within a trigger 1995** program, the value returned reflects the number of rows modified by the 1996** previous INSERT, UPDATE or DELETE statement within the same trigger. 1997** 1998** See also the [sqlite3_total_changes()] interface, the 1999** [count_changes pragma], and the [changes() SQL function]. 2000** 2001** If a separate thread makes changes on the same database connection 2002** while [sqlite3_changes()] is running then the value returned 2003** is unpredictable and not meaningful. 2004*/ 2005SQLITE_API int SQLITE_STDCALL sqlite3_changes(sqlite3*); 2006 2007/* 2008** CAPI3REF: Total Number Of Rows Modified 2009** METHOD: sqlite3 2010** 2011** ^This function returns the total number of rows inserted, modified or 2012** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2013** since the database connection was opened, including those executed as 2014** part of trigger programs. ^Executing any other type of SQL statement 2015** does not affect the value returned by sqlite3_total_changes(). 2016** 2017** ^Changes made as part of [foreign key actions] are included in the 2018** count, but those made as part of REPLACE constraint resolution are 2019** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2020** are not counted. 2021** 2022** See also the [sqlite3_changes()] interface, the 2023** [count_changes pragma], and the [total_changes() SQL function]. 2024** 2025** If a separate thread makes changes on the same database connection 2026** while [sqlite3_total_changes()] is running then the value 2027** returned is unpredictable and not meaningful. 2028*/ 2029SQLITE_API int SQLITE_STDCALL sqlite3_total_changes(sqlite3*); 2030 2031/* 2032** CAPI3REF: Interrupt A Long-Running Query 2033** METHOD: sqlite3 2034** 2035** ^This function causes any pending database operation to abort and 2036** return at its earliest opportunity. This routine is typically 2037** called in response to a user action such as pressing "Cancel" 2038** or Ctrl-C where the user wants a long query operation to halt 2039** immediately. 2040** 2041** ^It is safe to call this routine from a thread different from the 2042** thread that is currently running the database operation. But it 2043** is not safe to call this routine with a [database connection] that 2044** is closed or might close before sqlite3_interrupt() returns. 2045** 2046** ^If an SQL operation is very nearly finished at the time when 2047** sqlite3_interrupt() is called, then it might not have an opportunity 2048** to be interrupted and might continue to completion. 2049** 2050** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2051** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2052** that is inside an explicit transaction, then the entire transaction 2053** will be rolled back automatically. 2054** 2055** ^The sqlite3_interrupt(D) call is in effect until all currently running 2056** SQL statements on [database connection] D complete. ^Any new SQL statements 2057** that are started after the sqlite3_interrupt() call and before the 2058** running statements reaches zero are interrupted as if they had been 2059** running prior to the sqlite3_interrupt() call. ^New SQL statements 2060** that are started after the running statement count reaches zero are 2061** not effected by the sqlite3_interrupt(). 2062** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2063** SQL statements is a no-op and has no effect on SQL statements 2064** that are started after the sqlite3_interrupt() call returns. 2065** 2066** If the database connection closes while [sqlite3_interrupt()] 2067** is running then bad things will likely happen. 2068*/ 2069SQLITE_API void SQLITE_STDCALL sqlite3_interrupt(sqlite3*); 2070 2071/* 2072** CAPI3REF: Determine If An SQL Statement Is Complete 2073** 2074** These routines are useful during command-line input to determine if the 2075** currently entered text seems to form a complete SQL statement or 2076** if additional input is needed before sending the text into 2077** SQLite for parsing. ^These routines return 1 if the input string 2078** appears to be a complete SQL statement. ^A statement is judged to be 2079** complete if it ends with a semicolon token and is not a prefix of a 2080** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2081** string literals or quoted identifier names or comments are not 2082** independent tokens (they are part of the token in which they are 2083** embedded) and thus do not count as a statement terminator. ^Whitespace 2084** and comments that follow the final semicolon are ignored. 2085** 2086** ^These routines return 0 if the statement is incomplete. ^If a 2087** memory allocation fails, then SQLITE_NOMEM is returned. 2088** 2089** ^These routines do not parse the SQL statements thus 2090** will not detect syntactically incorrect SQL. 2091** 2092** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2093** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2094** automatically by sqlite3_complete16(). If that initialization fails, 2095** then the return value from sqlite3_complete16() will be non-zero 2096** regardless of whether or not the input SQL is complete.)^ 2097** 2098** The input to [sqlite3_complete()] must be a zero-terminated 2099** UTF-8 string. 2100** 2101** The input to [sqlite3_complete16()] must be a zero-terminated 2102** UTF-16 string in native byte order. 2103*/ 2104SQLITE_API int SQLITE_STDCALL sqlite3_complete(const char *sql); 2105SQLITE_API int SQLITE_STDCALL sqlite3_complete16(const void *sql); 2106 2107/* 2108** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2109** KEYWORDS: {busy-handler callback} {busy handler} 2110** METHOD: sqlite3 2111** 2112** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2113** that might be invoked with argument P whenever 2114** an attempt is made to access a database table associated with 2115** [database connection] D when another thread 2116** or process has the table locked. 2117** The sqlite3_busy_handler() interface is used to implement 2118** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2119** 2120** ^If the busy callback is NULL, then [SQLITE_BUSY] 2121** is returned immediately upon encountering the lock. ^If the busy callback 2122** is not NULL, then the callback might be invoked with two arguments. 2123** 2124** ^The first argument to the busy handler is a copy of the void* pointer which 2125** is the third argument to sqlite3_busy_handler(). ^The second argument to 2126** the busy handler callback is the number of times that the busy handler has 2127** been invoked previously for the same locking event. ^If the 2128** busy callback returns 0, then no additional attempts are made to 2129** access the database and [SQLITE_BUSY] is returned 2130** to the application. 2131** ^If the callback returns non-zero, then another attempt 2132** is made to access the database and the cycle repeats. 2133** 2134** The presence of a busy handler does not guarantee that it will be invoked 2135** when there is lock contention. ^If SQLite determines that invoking the busy 2136** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2137** to the application instead of invoking the 2138** busy handler. 2139** Consider a scenario where one process is holding a read lock that 2140** it is trying to promote to a reserved lock and 2141** a second process is holding a reserved lock that it is trying 2142** to promote to an exclusive lock. The first process cannot proceed 2143** because it is blocked by the second and the second process cannot 2144** proceed because it is blocked by the first. If both processes 2145** invoke the busy handlers, neither will make any progress. Therefore, 2146** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2147** will induce the first process to release its read lock and allow 2148** the second process to proceed. 2149** 2150** ^The default busy callback is NULL. 2151** 2152** ^(There can only be a single busy handler defined for each 2153** [database connection]. Setting a new busy handler clears any 2154** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2155** or evaluating [PRAGMA busy_timeout=N] will change the 2156** busy handler and thus clear any previously set busy handler. 2157** 2158** The busy callback should not take any actions which modify the 2159** database connection that invoked the busy handler. In other words, 2160** the busy handler is not reentrant. Any such actions 2161** result in undefined behavior. 2162** 2163** A busy handler must not close the database connection 2164** or [prepared statement] that invoked the busy handler. 2165*/ 2166SQLITE_API int SQLITE_STDCALL sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2167 2168/* 2169** CAPI3REF: Set A Busy Timeout 2170** METHOD: sqlite3 2171** 2172** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2173** for a specified amount of time when a table is locked. ^The handler 2174** will sleep multiple times until at least "ms" milliseconds of sleeping 2175** have accumulated. ^After at least "ms" milliseconds of sleeping, 2176** the handler returns 0 which causes [sqlite3_step()] to return 2177** [SQLITE_BUSY]. 2178** 2179** ^Calling this routine with an argument less than or equal to zero 2180** turns off all busy handlers. 2181** 2182** ^(There can only be a single busy handler for a particular 2183** [database connection] at any given moment. If another busy handler 2184** was defined (using [sqlite3_busy_handler()]) prior to calling 2185** this routine, that other busy handler is cleared.)^ 2186** 2187** See also: [PRAGMA busy_timeout] 2188*/ 2189SQLITE_API int SQLITE_STDCALL sqlite3_busy_timeout(sqlite3*, int ms); 2190 2191/* 2192** CAPI3REF: Convenience Routines For Running Queries 2193** METHOD: sqlite3 2194** 2195** This is a legacy interface that is preserved for backwards compatibility. 2196** Use of this interface is not recommended. 2197** 2198** Definition: A <b>result table</b> is memory data structure created by the 2199** [sqlite3_get_table()] interface. A result table records the 2200** complete query results from one or more queries. 2201** 2202** The table conceptually has a number of rows and columns. But 2203** these numbers are not part of the result table itself. These 2204** numbers are obtained separately. Let N be the number of rows 2205** and M be the number of columns. 2206** 2207** A result table is an array of pointers to zero-terminated UTF-8 strings. 2208** There are (N+1)*M elements in the array. The first M pointers point 2209** to zero-terminated strings that contain the names of the columns. 2210** The remaining entries all point to query results. NULL values result 2211** in NULL pointers. All other values are in their UTF-8 zero-terminated 2212** string representation as returned by [sqlite3_column_text()]. 2213** 2214** A result table might consist of one or more memory allocations. 2215** It is not safe to pass a result table directly to [sqlite3_free()]. 2216** A result table should be deallocated using [sqlite3_free_table()]. 2217** 2218** ^(As an example of the result table format, suppose a query result 2219** is as follows: 2220** 2221** <blockquote><pre> 2222** Name | Age 2223** ----------------------- 2224** Alice | 43 2225** Bob | 28 2226** Cindy | 21 2227** </pre></blockquote> 2228** 2229** There are two column (M==2) and three rows (N==3). Thus the 2230** result table has 8 entries. Suppose the result table is stored 2231** in an array names azResult. Then azResult holds this content: 2232** 2233** <blockquote><pre> 2234** azResult[0] = "Name"; 2235** azResult[1] = "Age"; 2236** azResult[2] = "Alice"; 2237** azResult[3] = "43"; 2238** azResult[4] = "Bob"; 2239** azResult[5] = "28"; 2240** azResult[6] = "Cindy"; 2241** azResult[7] = "21"; 2242** </pre></blockquote>)^ 2243** 2244** ^The sqlite3_get_table() function evaluates one or more 2245** semicolon-separated SQL statements in the zero-terminated UTF-8 2246** string of its 2nd parameter and returns a result table to the 2247** pointer given in its 3rd parameter. 2248** 2249** After the application has finished with the result from sqlite3_get_table(), 2250** it must pass the result table pointer to sqlite3_free_table() in order to 2251** release the memory that was malloced. Because of the way the 2252** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2253** function must not try to call [sqlite3_free()] directly. Only 2254** [sqlite3_free_table()] is able to release the memory properly and safely. 2255** 2256** The sqlite3_get_table() interface is implemented as a wrapper around 2257** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2258** to any internal data structures of SQLite. It uses only the public 2259** interface defined here. As a consequence, errors that occur in the 2260** wrapper layer outside of the internal [sqlite3_exec()] call are not 2261** reflected in subsequent calls to [sqlite3_errcode()] or 2262** [sqlite3_errmsg()]. 2263*/ 2264SQLITE_API int SQLITE_STDCALL sqlite3_get_table( 2265 sqlite3 *db, /* An open database */ 2266 const char *zSql, /* SQL to be evaluated */ 2267 char ***pazResult, /* Results of the query */ 2268 int *pnRow, /* Number of result rows written here */ 2269 int *pnColumn, /* Number of result columns written here */ 2270 char **pzErrmsg /* Error msg written here */ 2271); 2272SQLITE_API void SQLITE_STDCALL sqlite3_free_table(char **result); 2273 2274/* 2275** CAPI3REF: Formatted String Printing Functions 2276** 2277** These routines are work-alikes of the "printf()" family of functions 2278** from the standard C library. 2279** These routines understand most of the common K&R formatting options, 2280** plus some additional non-standard formats, detailed below. 2281** Note that some of the more obscure formatting options from recent 2282** C-library standards are omitted from this implementation. 2283** 2284** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2285** results into memory obtained from [sqlite3_malloc()]. 2286** The strings returned by these two routines should be 2287** released by [sqlite3_free()]. ^Both routines return a 2288** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2289** memory to hold the resulting string. 2290** 2291** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2292** the standard C library. The result is written into the 2293** buffer supplied as the second parameter whose size is given by 2294** the first parameter. Note that the order of the 2295** first two parameters is reversed from snprintf().)^ This is an 2296** historical accident that cannot be fixed without breaking 2297** backwards compatibility. ^(Note also that sqlite3_snprintf() 2298** returns a pointer to its buffer instead of the number of 2299** characters actually written into the buffer.)^ We admit that 2300** the number of characters written would be a more useful return 2301** value but we cannot change the implementation of sqlite3_snprintf() 2302** now without breaking compatibility. 2303** 2304** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2305** guarantees that the buffer is always zero-terminated. ^The first 2306** parameter "n" is the total size of the buffer, including space for 2307** the zero terminator. So the longest string that can be completely 2308** written will be n-1 characters. 2309** 2310** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2311** 2312** These routines all implement some additional formatting 2313** options that are useful for constructing SQL statements. 2314** All of the usual printf() formatting options apply. In addition, there 2315** is are "%q", "%Q", "%w" and "%z" options. 2316** 2317** ^(The %q option works like %s in that it substitutes a nul-terminated 2318** string from the argument list. But %q also doubles every '\'' character. 2319** %q is designed for use inside a string literal.)^ By doubling each '\'' 2320** character it escapes that character and allows it to be inserted into 2321** the string. 2322** 2323** For example, assume the string variable zText contains text as follows: 2324** 2325** <blockquote><pre> 2326** char *zText = "It's a happy day!"; 2327** </pre></blockquote> 2328** 2329** One can use this text in an SQL statement as follows: 2330** 2331** <blockquote><pre> 2332** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2333** sqlite3_exec(db, zSQL, 0, 0, 0); 2334** sqlite3_free(zSQL); 2335** </pre></blockquote> 2336** 2337** Because the %q format string is used, the '\'' character in zText 2338** is escaped and the SQL generated is as follows: 2339** 2340** <blockquote><pre> 2341** INSERT INTO table1 VALUES('It''s a happy day!') 2342** </pre></blockquote> 2343** 2344** This is correct. Had we used %s instead of %q, the generated SQL 2345** would have looked like this: 2346** 2347** <blockquote><pre> 2348** INSERT INTO table1 VALUES('It's a happy day!'); 2349** </pre></blockquote> 2350** 2351** This second example is an SQL syntax error. As a general rule you should 2352** always use %q instead of %s when inserting text into a string literal. 2353** 2354** ^(The %Q option works like %q except it also adds single quotes around 2355** the outside of the total string. Additionally, if the parameter in the 2356** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2357** single quotes).)^ So, for example, one could say: 2358** 2359** <blockquote><pre> 2360** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2361** sqlite3_exec(db, zSQL, 0, 0, 0); 2362** sqlite3_free(zSQL); 2363** </pre></blockquote> 2364** 2365** The code above will render a correct SQL statement in the zSQL 2366** variable even if the zText variable is a NULL pointer. 2367** 2368** ^(The "%w" formatting option is like "%q" except that it expects to 2369** be contained within double-quotes instead of single quotes, and it 2370** escapes the double-quote character instead of the single-quote 2371** character.)^ The "%w" formatting option is intended for safely inserting 2372** table and column names into a constructed SQL statement. 2373** 2374** ^(The "%z" formatting option works like "%s" but with the 2375** addition that after the string has been read and copied into 2376** the result, [sqlite3_free()] is called on the input string.)^ 2377*/ 2378SQLITE_API char *SQLITE_CDECL sqlite3_mprintf(const char*,...); 2379SQLITE_API char *SQLITE_STDCALL sqlite3_vmprintf(const char*, va_list); 2380SQLITE_API char *SQLITE_CDECL sqlite3_snprintf(int,char*,const char*, ...); 2381SQLITE_API char *SQLITE_STDCALL sqlite3_vsnprintf(int,char*,const char*, va_list); 2382 2383/* 2384** CAPI3REF: Memory Allocation Subsystem 2385** 2386** The SQLite core uses these three routines for all of its own 2387** internal memory allocation needs. "Core" in the previous sentence 2388** does not include operating-system specific VFS implementation. The 2389** Windows VFS uses native malloc() and free() for some operations. 2390** 2391** ^The sqlite3_malloc() routine returns a pointer to a block 2392** of memory at least N bytes in length, where N is the parameter. 2393** ^If sqlite3_malloc() is unable to obtain sufficient free 2394** memory, it returns a NULL pointer. ^If the parameter N to 2395** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2396** a NULL pointer. 2397** 2398** ^The sqlite3_malloc64(N) routine works just like 2399** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2400** of a signed 32-bit integer. 2401** 2402** ^Calling sqlite3_free() with a pointer previously returned 2403** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2404** that it might be reused. ^The sqlite3_free() routine is 2405** a no-op if is called with a NULL pointer. Passing a NULL pointer 2406** to sqlite3_free() is harmless. After being freed, memory 2407** should neither be read nor written. Even reading previously freed 2408** memory might result in a segmentation fault or other severe error. 2409** Memory corruption, a segmentation fault, or other severe error 2410** might result if sqlite3_free() is called with a non-NULL pointer that 2411** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2412** 2413** ^The sqlite3_realloc(X,N) interface attempts to resize a 2414** prior memory allocation X to be at least N bytes. 2415** ^If the X parameter to sqlite3_realloc(X,N) 2416** is a NULL pointer then its behavior is identical to calling 2417** sqlite3_malloc(N). 2418** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2419** negative then the behavior is exactly the same as calling 2420** sqlite3_free(X). 2421** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2422** of at least N bytes in size or NULL if insufficient memory is available. 2423** ^If M is the size of the prior allocation, then min(N,M) bytes 2424** of the prior allocation are copied into the beginning of buffer returned 2425** by sqlite3_realloc(X,N) and the prior allocation is freed. 2426** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2427** prior allocation is not freed. 2428** 2429** ^The sqlite3_realloc64(X,N) interfaces works the same as 2430** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2431** of a 32-bit signed integer. 2432** 2433** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2434** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2435** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2436** ^The value returned by sqlite3_msize(X) might be larger than the number 2437** of bytes requested when X was allocated. ^If X is a NULL pointer then 2438** sqlite3_msize(X) returns zero. If X points to something that is not 2439** the beginning of memory allocation, or if it points to a formerly 2440** valid memory allocation that has now been freed, then the behavior 2441** of sqlite3_msize(X) is undefined and possibly harmful. 2442** 2443** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2444** sqlite3_malloc64(), and sqlite3_realloc64() 2445** is always aligned to at least an 8 byte boundary, or to a 2446** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2447** option is used. 2448** 2449** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2450** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2451** implementation of these routines to be omitted. That capability 2452** is no longer provided. Only built-in memory allocators can be used. 2453** 2454** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2455** the system malloc() and free() directly when converting 2456** filenames between the UTF-8 encoding used by SQLite 2457** and whatever filename encoding is used by the particular Windows 2458** installation. Memory allocation errors were detected, but 2459** they were reported back as [SQLITE_CANTOPEN] or 2460** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2461** 2462** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2463** must be either NULL or else pointers obtained from a prior 2464** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2465** not yet been released. 2466** 2467** The application must not read or write any part of 2468** a block of memory after it has been released using 2469** [sqlite3_free()] or [sqlite3_realloc()]. 2470*/ 2471SQLITE_API void *SQLITE_STDCALL sqlite3_malloc(int); 2472SQLITE_API void *SQLITE_STDCALL sqlite3_malloc64(sqlite3_uint64); 2473SQLITE_API void *SQLITE_STDCALL sqlite3_realloc(void*, int); 2474SQLITE_API void *SQLITE_STDCALL sqlite3_realloc64(void*, sqlite3_uint64); 2475SQLITE_API void SQLITE_STDCALL sqlite3_free(void*); 2476SQLITE_API sqlite3_uint64 SQLITE_STDCALL sqlite3_msize(void*); 2477 2478/* 2479** CAPI3REF: Memory Allocator Statistics 2480** 2481** SQLite provides these two interfaces for reporting on the status 2482** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2483** routines, which form the built-in memory allocation subsystem. 2484** 2485** ^The [sqlite3_memory_used()] routine returns the number of bytes 2486** of memory currently outstanding (malloced but not freed). 2487** ^The [sqlite3_memory_highwater()] routine returns the maximum 2488** value of [sqlite3_memory_used()] since the high-water mark 2489** was last reset. ^The values returned by [sqlite3_memory_used()] and 2490** [sqlite3_memory_highwater()] include any overhead 2491** added by SQLite in its implementation of [sqlite3_malloc()], 2492** but not overhead added by the any underlying system library 2493** routines that [sqlite3_malloc()] may call. 2494** 2495** ^The memory high-water mark is reset to the current value of 2496** [sqlite3_memory_used()] if and only if the parameter to 2497** [sqlite3_memory_highwater()] is true. ^The value returned 2498** by [sqlite3_memory_highwater(1)] is the high-water mark 2499** prior to the reset. 2500*/ 2501SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_used(void); 2502SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_highwater(int resetFlag); 2503 2504/* 2505** CAPI3REF: Pseudo-Random Number Generator 2506** 2507** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2508** select random [ROWID | ROWIDs] when inserting new records into a table that 2509** already uses the largest possible [ROWID]. The PRNG is also used for 2510** the build-in random() and randomblob() SQL functions. This interface allows 2511** applications to access the same PRNG for other purposes. 2512** 2513** ^A call to this routine stores N bytes of randomness into buffer P. 2514** ^The P parameter can be a NULL pointer. 2515** 2516** ^If this routine has not been previously called or if the previous 2517** call had N less than one or a NULL pointer for P, then the PRNG is 2518** seeded using randomness obtained from the xRandomness method of 2519** the default [sqlite3_vfs] object. 2520** ^If the previous call to this routine had an N of 1 or more and a 2521** non-NULL P then the pseudo-randomness is generated 2522** internally and without recourse to the [sqlite3_vfs] xRandomness 2523** method. 2524*/ 2525SQLITE_API void SQLITE_STDCALL sqlite3_randomness(int N, void *P); 2526 2527/* 2528** CAPI3REF: Compile-Time Authorization Callbacks 2529** METHOD: sqlite3 2530** 2531** ^This routine registers an authorizer callback with a particular 2532** [database connection], supplied in the first argument. 2533** ^The authorizer callback is invoked as SQL statements are being compiled 2534** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2535** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2536** points during the compilation process, as logic is being created 2537** to perform various actions, the authorizer callback is invoked to 2538** see if those actions are allowed. ^The authorizer callback should 2539** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2540** specific action but allow the SQL statement to continue to be 2541** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2542** rejected with an error. ^If the authorizer callback returns 2543** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2544** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2545** the authorizer will fail with an error message. 2546** 2547** When the callback returns [SQLITE_OK], that means the operation 2548** requested is ok. ^When the callback returns [SQLITE_DENY], the 2549** [sqlite3_prepare_v2()] or equivalent call that triggered the 2550** authorizer will fail with an error message explaining that 2551** access is denied. 2552** 2553** ^The first parameter to the authorizer callback is a copy of the third 2554** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2555** to the callback is an integer [SQLITE_COPY | action code] that specifies 2556** the particular action to be authorized. ^The third through sixth parameters 2557** to the callback are zero-terminated strings that contain additional 2558** details about the action to be authorized. 2559** 2560** ^If the action code is [SQLITE_READ] 2561** and the callback returns [SQLITE_IGNORE] then the 2562** [prepared statement] statement is constructed to substitute 2563** a NULL value in place of the table column that would have 2564** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2565** return can be used to deny an untrusted user access to individual 2566** columns of a table. 2567** ^If the action code is [SQLITE_DELETE] and the callback returns 2568** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2569** [truncate optimization] is disabled and all rows are deleted individually. 2570** 2571** An authorizer is used when [sqlite3_prepare | preparing] 2572** SQL statements from an untrusted source, to ensure that the SQL statements 2573** do not try to access data they are not allowed to see, or that they do not 2574** try to execute malicious statements that damage the database. For 2575** example, an application may allow a user to enter arbitrary 2576** SQL queries for evaluation by a database. But the application does 2577** not want the user to be able to make arbitrary changes to the 2578** database. An authorizer could then be put in place while the 2579** user-entered SQL is being [sqlite3_prepare | prepared] that 2580** disallows everything except [SELECT] statements. 2581** 2582** Applications that need to process SQL from untrusted sources 2583** might also consider lowering resource limits using [sqlite3_limit()] 2584** and limiting database size using the [max_page_count] [PRAGMA] 2585** in addition to using an authorizer. 2586** 2587** ^(Only a single authorizer can be in place on a database connection 2588** at a time. Each call to sqlite3_set_authorizer overrides the 2589** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2590** The authorizer is disabled by default. 2591** 2592** The authorizer callback must not do anything that will modify 2593** the database connection that invoked the authorizer callback. 2594** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2595** database connections for the meaning of "modify" in this paragraph. 2596** 2597** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2598** statement might be re-prepared during [sqlite3_step()] due to a 2599** schema change. Hence, the application should ensure that the 2600** correct authorizer callback remains in place during the [sqlite3_step()]. 2601** 2602** ^Note that the authorizer callback is invoked only during 2603** [sqlite3_prepare()] or its variants. Authorization is not 2604** performed during statement evaluation in [sqlite3_step()], unless 2605** as stated in the previous paragraph, sqlite3_step() invokes 2606** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2607*/ 2608SQLITE_API int SQLITE_STDCALL sqlite3_set_authorizer( 2609 sqlite3*, 2610 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2611 void *pUserData 2612); 2613 2614/* 2615** CAPI3REF: Authorizer Return Codes 2616** 2617** The [sqlite3_set_authorizer | authorizer callback function] must 2618** return either [SQLITE_OK] or one of these two constants in order 2619** to signal SQLite whether or not the action is permitted. See the 2620** [sqlite3_set_authorizer | authorizer documentation] for additional 2621** information. 2622** 2623** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2624** returned from the [sqlite3_vtab_on_conflict()] interface. 2625*/ 2626#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2627#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2628 2629/* 2630** CAPI3REF: Authorizer Action Codes 2631** 2632** The [sqlite3_set_authorizer()] interface registers a callback function 2633** that is invoked to authorize certain SQL statement actions. The 2634** second parameter to the callback is an integer code that specifies 2635** what action is being authorized. These are the integer action codes that 2636** the authorizer callback may be passed. 2637** 2638** These action code values signify what kind of operation is to be 2639** authorized. The 3rd and 4th parameters to the authorization 2640** callback function will be parameters or NULL depending on which of these 2641** codes is used as the second parameter. ^(The 5th parameter to the 2642** authorizer callback is the name of the database ("main", "temp", 2643** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2644** is the name of the inner-most trigger or view that is responsible for 2645** the access attempt or NULL if this access attempt is directly from 2646** top-level SQL code. 2647*/ 2648/******************************************* 3rd ************ 4th ***********/ 2649#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2650#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2651#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2652#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2653#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2654#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2655#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2656#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2657#define SQLITE_DELETE 9 /* Table Name NULL */ 2658#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2659#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2660#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2661#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2662#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2663#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2664#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2665#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2666#define SQLITE_INSERT 18 /* Table Name NULL */ 2667#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2668#define SQLITE_READ 20 /* Table Name Column Name */ 2669#define SQLITE_SELECT 21 /* NULL NULL */ 2670#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2671#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2672#define SQLITE_ATTACH 24 /* Filename NULL */ 2673#define SQLITE_DETACH 25 /* Database Name NULL */ 2674#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2675#define SQLITE_REINDEX 27 /* Index Name NULL */ 2676#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2677#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2678#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2679#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2680#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2681#define SQLITE_COPY 0 /* No longer used */ 2682#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2683 2684/* 2685** CAPI3REF: Tracing And Profiling Functions 2686** METHOD: sqlite3 2687** 2688** These routines register callback functions that can be used for 2689** tracing and profiling the execution of SQL statements. 2690** 2691** ^The callback function registered by sqlite3_trace() is invoked at 2692** various times when an SQL statement is being run by [sqlite3_step()]. 2693** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2694** SQL statement text as the statement first begins executing. 2695** ^(Additional sqlite3_trace() callbacks might occur 2696** as each triggered subprogram is entered. The callbacks for triggers 2697** contain a UTF-8 SQL comment that identifies the trigger.)^ 2698** 2699** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2700** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2701** 2702** ^The callback function registered by sqlite3_profile() is invoked 2703** as each SQL statement finishes. ^The profile callback contains 2704** the original statement text and an estimate of wall-clock time 2705** of how long that statement took to run. ^The profile callback 2706** time is in units of nanoseconds, however the current implementation 2707** is only capable of millisecond resolution so the six least significant 2708** digits in the time are meaningless. Future versions of SQLite 2709** might provide greater resolution on the profiler callback. The 2710** sqlite3_profile() function is considered experimental and is 2711** subject to change in future versions of SQLite. 2712*/ 2713SQLITE_API void *SQLITE_STDCALL sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2714SQLITE_API SQLITE_EXPERIMENTAL void *SQLITE_STDCALL sqlite3_profile(sqlite3*, 2715 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2716 2717/* 2718** CAPI3REF: Query Progress Callbacks 2719** METHOD: sqlite3 2720** 2721** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2722** function X to be invoked periodically during long running calls to 2723** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2724** database connection D. An example use for this 2725** interface is to keep a GUI updated during a large query. 2726** 2727** ^The parameter P is passed through as the only parameter to the 2728** callback function X. ^The parameter N is the approximate number of 2729** [virtual machine instructions] that are evaluated between successive 2730** invocations of the callback X. ^If N is less than one then the progress 2731** handler is disabled. 2732** 2733** ^Only a single progress handler may be defined at one time per 2734** [database connection]; setting a new progress handler cancels the 2735** old one. ^Setting parameter X to NULL disables the progress handler. 2736** ^The progress handler is also disabled by setting N to a value less 2737** than 1. 2738** 2739** ^If the progress callback returns non-zero, the operation is 2740** interrupted. This feature can be used to implement a 2741** "Cancel" button on a GUI progress dialog box. 2742** 2743** The progress handler callback must not do anything that will modify 2744** the database connection that invoked the progress handler. 2745** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2746** database connections for the meaning of "modify" in this paragraph. 2747** 2748*/ 2749SQLITE_API void SQLITE_STDCALL sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2750 2751/* 2752** CAPI3REF: Opening A New Database Connection 2753** CONSTRUCTOR: sqlite3 2754** 2755** ^These routines open an SQLite database file as specified by the 2756** filename argument. ^The filename argument is interpreted as UTF-8 for 2757** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2758** order for sqlite3_open16(). ^(A [database connection] handle is usually 2759** returned in *ppDb, even if an error occurs. The only exception is that 2760** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2761** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2762** object.)^ ^(If the database is opened (and/or created) successfully, then 2763** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2764** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2765** an English language description of the error following a failure of any 2766** of the sqlite3_open() routines. 2767** 2768** ^The default encoding will be UTF-8 for databases created using 2769** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 2770** created using sqlite3_open16() will be UTF-16 in the native byte order. 2771** 2772** Whether or not an error occurs when it is opened, resources 2773** associated with the [database connection] handle should be released by 2774** passing it to [sqlite3_close()] when it is no longer required. 2775** 2776** The sqlite3_open_v2() interface works like sqlite3_open() 2777** except that it accepts two additional parameters for additional control 2778** over the new database connection. ^(The flags parameter to 2779** sqlite3_open_v2() can take one of 2780** the following three values, optionally combined with the 2781** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2782** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2783** 2784** <dl> 2785** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2786** <dd>The database is opened in read-only mode. If the database does not 2787** already exist, an error is returned.</dd>)^ 2788** 2789** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2790** <dd>The database is opened for reading and writing if possible, or reading 2791** only if the file is write protected by the operating system. In either 2792** case the database must already exist, otherwise an error is returned.</dd>)^ 2793** 2794** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2795** <dd>The database is opened for reading and writing, and is created if 2796** it does not already exist. This is the behavior that is always used for 2797** sqlite3_open() and sqlite3_open16().</dd>)^ 2798** </dl> 2799** 2800** If the 3rd parameter to sqlite3_open_v2() is not one of the 2801** combinations shown above optionally combined with other 2802** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2803** then the behavior is undefined. 2804** 2805** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2806** opens in the multi-thread [threading mode] as long as the single-thread 2807** mode has not been set at compile-time or start-time. ^If the 2808** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2809** in the serialized [threading mode] unless single-thread was 2810** previously selected at compile-time or start-time. 2811** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2812** eligible to use [shared cache mode], regardless of whether or not shared 2813** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2814** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2815** participate in [shared cache mode] even if it is enabled. 2816** 2817** ^The fourth parameter to sqlite3_open_v2() is the name of the 2818** [sqlite3_vfs] object that defines the operating system interface that 2819** the new database connection should use. ^If the fourth parameter is 2820** a NULL pointer then the default [sqlite3_vfs] object is used. 2821** 2822** ^If the filename is ":memory:", then a private, temporary in-memory database 2823** is created for the connection. ^This in-memory database will vanish when 2824** the database connection is closed. Future versions of SQLite might 2825** make use of additional special filenames that begin with the ":" character. 2826** It is recommended that when a database filename actually does begin with 2827** a ":" character you should prefix the filename with a pathname such as 2828** "./" to avoid ambiguity. 2829** 2830** ^If the filename is an empty string, then a private, temporary 2831** on-disk database will be created. ^This private database will be 2832** automatically deleted as soon as the database connection is closed. 2833** 2834** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2835** 2836** ^If [URI filename] interpretation is enabled, and the filename argument 2837** begins with "file:", then the filename is interpreted as a URI. ^URI 2838** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2839** set in the fourth argument to sqlite3_open_v2(), or if it has 2840** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2841** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2842** As of SQLite version 3.7.7, URI filename interpretation is turned off 2843** by default, but future releases of SQLite might enable URI filename 2844** interpretation by default. See "[URI filenames]" for additional 2845** information. 2846** 2847** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2848** authority, then it must be either an empty string or the string 2849** "localhost". ^If the authority is not an empty string or "localhost", an 2850** error is returned to the caller. ^The fragment component of a URI, if 2851** present, is ignored. 2852** 2853** ^SQLite uses the path component of the URI as the name of the disk file 2854** which contains the database. ^If the path begins with a '/' character, 2855** then it is interpreted as an absolute path. ^If the path does not begin 2856** with a '/' (meaning that the authority section is omitted from the URI) 2857** then the path is interpreted as a relative path. 2858** ^(On windows, the first component of an absolute path 2859** is a drive specification (e.g. "C:").)^ 2860** 2861** [[core URI query parameters]] 2862** The query component of a URI may contain parameters that are interpreted 2863** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2864** SQLite and its built-in [VFSes] interpret the 2865** following query parameters: 2866** 2867** <ul> 2868** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2869** a VFS object that provides the operating system interface that should 2870** be used to access the database file on disk. ^If this option is set to 2871** an empty string the default VFS object is used. ^Specifying an unknown 2872** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2873** present, then the VFS specified by the option takes precedence over 2874** the value passed as the fourth parameter to sqlite3_open_v2(). 2875** 2876** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2877** "rwc", or "memory". Attempting to set it to any other value is 2878** an error)^. 2879** ^If "ro" is specified, then the database is opened for read-only 2880** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2881** third argument to sqlite3_open_v2(). ^If the mode option is set to 2882** "rw", then the database is opened for read-write (but not create) 2883** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2884** been set. ^Value "rwc" is equivalent to setting both 2885** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2886** set to "memory" then a pure [in-memory database] that never reads 2887** or writes from disk is used. ^It is an error to specify a value for 2888** the mode parameter that is less restrictive than that specified by 2889** the flags passed in the third parameter to sqlite3_open_v2(). 2890** 2891** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2892** "private". ^Setting it to "shared" is equivalent to setting the 2893** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2894** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2895** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2896** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2897** a URI filename, its value overrides any behavior requested by setting 2898** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2899** 2900** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 2901** [powersafe overwrite] property does or does not apply to the 2902** storage media on which the database file resides. 2903** 2904** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 2905** which if set disables file locking in rollback journal modes. This 2906** is useful for accessing a database on a filesystem that does not 2907** support locking. Caution: Database corruption might result if two 2908** or more processes write to the same database and any one of those 2909** processes uses nolock=1. 2910** 2911** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 2912** parameter that indicates that the database file is stored on 2913** read-only media. ^When immutable is set, SQLite assumes that the 2914** database file cannot be changed, even by a process with higher 2915** privilege, and so the database is opened read-only and all locking 2916** and change detection is disabled. Caution: Setting the immutable 2917** property on a database file that does in fact change can result 2918** in incorrect query results and/or [SQLITE_CORRUPT] errors. 2919** See also: [SQLITE_IOCAP_IMMUTABLE]. 2920** 2921** </ul> 2922** 2923** ^Specifying an unknown parameter in the query component of a URI is not an 2924** error. Future versions of SQLite might understand additional query 2925** parameters. See "[query parameters with special meaning to SQLite]" for 2926** additional information. 2927** 2928** [[URI filename examples]] <h3>URI filename examples</h3> 2929** 2930** <table border="1" align=center cellpadding=5> 2931** <tr><th> URI filenames <th> Results 2932** <tr><td> file:data.db <td> 2933** Open the file "data.db" in the current directory. 2934** <tr><td> file:/home/fred/data.db<br> 2935** file:///home/fred/data.db <br> 2936** file://localhost/home/fred/data.db <br> <td> 2937** Open the database file "/home/fred/data.db". 2938** <tr><td> file://darkstar/home/fred/data.db <td> 2939** An error. "darkstar" is not a recognized authority. 2940** <tr><td style="white-space:nowrap"> 2941** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2942** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2943** C:. Note that the %20 escaping in this example is not strictly 2944** necessary - space characters can be used literally 2945** in URI filenames. 2946** <tr><td> file:data.db?mode=ro&cache=private <td> 2947** Open file "data.db" in the current directory for read-only access. 2948** Regardless of whether or not shared-cache mode is enabled by 2949** default, use a private cache. 2950** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 2951** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 2952** that uses dot-files in place of posix advisory locking. 2953** <tr><td> file:data.db?mode=readonly <td> 2954** An error. "readonly" is not a valid option for the "mode" parameter. 2955** </table> 2956** 2957** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2958** query components of a URI. A hexadecimal escape sequence consists of a 2959** percent sign - "%" - followed by exactly two hexadecimal digits 2960** specifying an octet value. ^Before the path or query components of a 2961** URI filename are interpreted, they are encoded using UTF-8 and all 2962** hexadecimal escape sequences replaced by a single byte containing the 2963** corresponding octet. If this process generates an invalid UTF-8 encoding, 2964** the results are undefined. 2965** 2966** <b>Note to Windows users:</b> The encoding used for the filename argument 2967** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2968** codepage is currently defined. Filenames containing international 2969** characters must be converted to UTF-8 prior to passing them into 2970** sqlite3_open() or sqlite3_open_v2(). 2971** 2972** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2973** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2974** features that require the use of temporary files may fail. 2975** 2976** See also: [sqlite3_temp_directory] 2977*/ 2978SQLITE_API int SQLITE_STDCALL sqlite3_open( 2979 const char *filename, /* Database filename (UTF-8) */ 2980 sqlite3 **ppDb /* OUT: SQLite db handle */ 2981); 2982SQLITE_API int SQLITE_STDCALL sqlite3_open16( 2983 const void *filename, /* Database filename (UTF-16) */ 2984 sqlite3 **ppDb /* OUT: SQLite db handle */ 2985); 2986SQLITE_API int SQLITE_STDCALL sqlite3_open_v2( 2987 const char *filename, /* Database filename (UTF-8) */ 2988 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2989 int flags, /* Flags */ 2990 const char *zVfs /* Name of VFS module to use */ 2991); 2992 2993/* 2994** CAPI3REF: Obtain Values For URI Parameters 2995** 2996** These are utility routines, useful to VFS implementations, that check 2997** to see if a database file was a URI that contained a specific query 2998** parameter, and if so obtains the value of that query parameter. 2999** 3000** If F is the database filename pointer passed into the xOpen() method of 3001** a VFS implementation when the flags parameter to xOpen() has one or 3002** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3003** P is the name of the query parameter, then 3004** sqlite3_uri_parameter(F,P) returns the value of the P 3005** parameter if it exists or a NULL pointer if P does not appear as a 3006** query parameter on F. If P is a query parameter of F 3007** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3008** a pointer to an empty string. 3009** 3010** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3011** parameter and returns true (1) or false (0) according to the value 3012** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3013** value of query parameter P is one of "yes", "true", or "on" in any 3014** case or if the value begins with a non-zero number. The 3015** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3016** query parameter P is one of "no", "false", or "off" in any case or 3017** if the value begins with a numeric zero. If P is not a query 3018** parameter on F or if the value of P is does not match any of the 3019** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3020** 3021** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3022** 64-bit signed integer and returns that integer, or D if P does not 3023** exist. If the value of P is something other than an integer, then 3024** zero is returned. 3025** 3026** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3027** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3028** is not a database file pathname pointer that SQLite passed into the xOpen 3029** VFS method, then the behavior of this routine is undefined and probably 3030** undesirable. 3031*/ 3032SQLITE_API const char *SQLITE_STDCALL sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3033SQLITE_API int SQLITE_STDCALL sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3034SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3035 3036 3037/* 3038** CAPI3REF: Error Codes And Messages 3039** METHOD: sqlite3 3040** 3041** ^If the most recent sqlite3_* API call associated with 3042** [database connection] D failed, then the sqlite3_errcode(D) interface 3043** returns the numeric [result code] or [extended result code] for that 3044** API call. 3045** If the most recent API call was successful, 3046** then the return value from sqlite3_errcode() is undefined. 3047** ^The sqlite3_extended_errcode() 3048** interface is the same except that it always returns the 3049** [extended result code] even when extended result codes are 3050** disabled. 3051** 3052** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3053** text that describes the error, as either UTF-8 or UTF-16 respectively. 3054** ^(Memory to hold the error message string is managed internally. 3055** The application does not need to worry about freeing the result. 3056** However, the error string might be overwritten or deallocated by 3057** subsequent calls to other SQLite interface functions.)^ 3058** 3059** ^The sqlite3_errstr() interface returns the English-language text 3060** that describes the [result code], as UTF-8. 3061** ^(Memory to hold the error message string is managed internally 3062** and must not be freed by the application)^. 3063** 3064** When the serialized [threading mode] is in use, it might be the 3065** case that a second error occurs on a separate thread in between 3066** the time of the first error and the call to these interfaces. 3067** When that happens, the second error will be reported since these 3068** interfaces always report the most recent result. To avoid 3069** this, each thread can obtain exclusive use of the [database connection] D 3070** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3071** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3072** all calls to the interfaces listed here are completed. 3073** 3074** If an interface fails with SQLITE_MISUSE, that means the interface 3075** was invoked incorrectly by the application. In that case, the 3076** error code and message may or may not be set. 3077*/ 3078SQLITE_API int SQLITE_STDCALL sqlite3_errcode(sqlite3 *db); 3079SQLITE_API int SQLITE_STDCALL sqlite3_extended_errcode(sqlite3 *db); 3080SQLITE_API const char *SQLITE_STDCALL sqlite3_errmsg(sqlite3*); 3081SQLITE_API const void *SQLITE_STDCALL sqlite3_errmsg16(sqlite3*); 3082SQLITE_API const char *SQLITE_STDCALL sqlite3_errstr(int); 3083 3084/* 3085** CAPI3REF: Prepared Statement Object 3086** KEYWORDS: {prepared statement} {prepared statements} 3087** 3088** An instance of this object represents a single SQL statement that 3089** has been compiled into binary form and is ready to be evaluated. 3090** 3091** Think of each SQL statement as a separate computer program. The 3092** original SQL text is source code. A prepared statement object 3093** is the compiled object code. All SQL must be converted into a 3094** prepared statement before it can be run. 3095** 3096** The life-cycle of a prepared statement object usually goes like this: 3097** 3098** <ol> 3099** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3100** <li> Bind values to [parameters] using the sqlite3_bind_*() 3101** interfaces. 3102** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3103** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3104** to step 2. Do this zero or more times. 3105** <li> Destroy the object using [sqlite3_finalize()]. 3106** </ol> 3107*/ 3108typedef struct sqlite3_stmt sqlite3_stmt; 3109 3110/* 3111** CAPI3REF: Run-time Limits 3112** METHOD: sqlite3 3113** 3114** ^(This interface allows the size of various constructs to be limited 3115** on a connection by connection basis. The first parameter is the 3116** [database connection] whose limit is to be set or queried. The 3117** second parameter is one of the [limit categories] that define a 3118** class of constructs to be size limited. The third parameter is the 3119** new limit for that construct.)^ 3120** 3121** ^If the new limit is a negative number, the limit is unchanged. 3122** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3123** [limits | hard upper bound] 3124** set at compile-time by a C preprocessor macro called 3125** [limits | SQLITE_MAX_<i>NAME</i>]. 3126** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3127** ^Attempts to increase a limit above its hard upper bound are 3128** silently truncated to the hard upper bound. 3129** 3130** ^Regardless of whether or not the limit was changed, the 3131** [sqlite3_limit()] interface returns the prior value of the limit. 3132** ^Hence, to find the current value of a limit without changing it, 3133** simply invoke this interface with the third parameter set to -1. 3134** 3135** Run-time limits are intended for use in applications that manage 3136** both their own internal database and also databases that are controlled 3137** by untrusted external sources. An example application might be a 3138** web browser that has its own databases for storing history and 3139** separate databases controlled by JavaScript applications downloaded 3140** off the Internet. The internal databases can be given the 3141** large, default limits. Databases managed by external sources can 3142** be given much smaller limits designed to prevent a denial of service 3143** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3144** interface to further control untrusted SQL. The size of the database 3145** created by an untrusted script can be contained using the 3146** [max_page_count] [PRAGMA]. 3147** 3148** New run-time limit categories may be added in future releases. 3149*/ 3150SQLITE_API int SQLITE_STDCALL sqlite3_limit(sqlite3*, int id, int newVal); 3151 3152/* 3153** CAPI3REF: Run-Time Limit Categories 3154** KEYWORDS: {limit category} {*limit categories} 3155** 3156** These constants define various performance limits 3157** that can be lowered at run-time using [sqlite3_limit()]. 3158** The synopsis of the meanings of the various limits is shown below. 3159** Additional information is available at [limits | Limits in SQLite]. 3160** 3161** <dl> 3162** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3163** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3164** 3165** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3166** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3167** 3168** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3169** <dd>The maximum number of columns in a table definition or in the 3170** result set of a [SELECT] or the maximum number of columns in an index 3171** or in an ORDER BY or GROUP BY clause.</dd>)^ 3172** 3173** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3174** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3175** 3176** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3177** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3178** 3179** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3180** <dd>The maximum number of instructions in a virtual machine program 3181** used to implement an SQL statement. This limit is not currently 3182** enforced, though that might be added in some future release of 3183** SQLite.</dd>)^ 3184** 3185** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3186** <dd>The maximum number of arguments on a function.</dd>)^ 3187** 3188** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3189** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3190** 3191** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3192** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3193** <dd>The maximum length of the pattern argument to the [LIKE] or 3194** [GLOB] operators.</dd>)^ 3195** 3196** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3197** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3198** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3199** 3200** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3201** <dd>The maximum depth of recursion for triggers.</dd>)^ 3202** 3203** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3204** <dd>The maximum number of auxiliary worker threads that a single 3205** [prepared statement] may start.</dd>)^ 3206** </dl> 3207*/ 3208#define SQLITE_LIMIT_LENGTH 0 3209#define SQLITE_LIMIT_SQL_LENGTH 1 3210#define SQLITE_LIMIT_COLUMN 2 3211#define SQLITE_LIMIT_EXPR_DEPTH 3 3212#define SQLITE_LIMIT_COMPOUND_SELECT 4 3213#define SQLITE_LIMIT_VDBE_OP 5 3214#define SQLITE_LIMIT_FUNCTION_ARG 6 3215#define SQLITE_LIMIT_ATTACHED 7 3216#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3217#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3218#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3219#define SQLITE_LIMIT_WORKER_THREADS 11 3220 3221/* 3222** CAPI3REF: Compiling An SQL Statement 3223** KEYWORDS: {SQL statement compiler} 3224** METHOD: sqlite3 3225** CONSTRUCTOR: sqlite3_stmt 3226** 3227** To execute an SQL query, it must first be compiled into a byte-code 3228** program using one of these routines. 3229** 3230** The first argument, "db", is a [database connection] obtained from a 3231** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3232** [sqlite3_open16()]. The database connection must not have been closed. 3233** 3234** The second argument, "zSql", is the statement to be compiled, encoded 3235** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3236** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3237** use UTF-16. 3238** 3239** ^If the nByte argument is negative, then zSql is read up to the 3240** first zero terminator. ^If nByte is positive, then it is the 3241** number of bytes read from zSql. ^If nByte is zero, then no prepared 3242** statement is generated. 3243** If the caller knows that the supplied string is nul-terminated, then 3244** there is a small performance advantage to passing an nByte parameter that 3245** is the number of bytes in the input string <i>including</i> 3246** the nul-terminator. 3247** 3248** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3249** past the end of the first SQL statement in zSql. These routines only 3250** compile the first statement in zSql, so *pzTail is left pointing to 3251** what remains uncompiled. 3252** 3253** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3254** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3255** to NULL. ^If the input text contains no SQL (if the input is an empty 3256** string or a comment) then *ppStmt is set to NULL. 3257** The calling procedure is responsible for deleting the compiled 3258** SQL statement using [sqlite3_finalize()] after it has finished with it. 3259** ppStmt may not be NULL. 3260** 3261** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3262** otherwise an [error code] is returned. 3263** 3264** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3265** recommended for all new programs. The two older interfaces are retained 3266** for backwards compatibility, but their use is discouraged. 3267** ^In the "v2" interfaces, the prepared statement 3268** that is returned (the [sqlite3_stmt] object) contains a copy of the 3269** original SQL text. This causes the [sqlite3_step()] interface to 3270** behave differently in three ways: 3271** 3272** <ol> 3273** <li> 3274** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3275** always used to do, [sqlite3_step()] will automatically recompile the SQL 3276** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3277** retries will occur before sqlite3_step() gives up and returns an error. 3278** </li> 3279** 3280** <li> 3281** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3282** [error codes] or [extended error codes]. ^The legacy behavior was that 3283** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3284** and the application would have to make a second call to [sqlite3_reset()] 3285** in order to find the underlying cause of the problem. With the "v2" prepare 3286** interfaces, the underlying reason for the error is returned immediately. 3287** </li> 3288** 3289** <li> 3290** ^If the specific value bound to [parameter | host parameter] in the 3291** WHERE clause might influence the choice of query plan for a statement, 3292** then the statement will be automatically recompiled, as if there had been 3293** a schema change, on the first [sqlite3_step()] call following any change 3294** to the [sqlite3_bind_text | bindings] of that [parameter]. 3295** ^The specific value of WHERE-clause [parameter] might influence the 3296** choice of query plan if the parameter is the left-hand side of a [LIKE] 3297** or [GLOB] operator or if the parameter is compared to an indexed column 3298** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3299** </li> 3300** </ol> 3301*/ 3302SQLITE_API int SQLITE_STDCALL sqlite3_prepare( 3303 sqlite3 *db, /* Database handle */ 3304 const char *zSql, /* SQL statement, UTF-8 encoded */ 3305 int nByte, /* Maximum length of zSql in bytes. */ 3306 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3307 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3308); 3309SQLITE_API int SQLITE_STDCALL sqlite3_prepare_v2( 3310 sqlite3 *db, /* Database handle */ 3311 const char *zSql, /* SQL statement, UTF-8 encoded */ 3312 int nByte, /* Maximum length of zSql in bytes. */ 3313 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3314 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3315); 3316SQLITE_API int SQLITE_STDCALL sqlite3_prepare16( 3317 sqlite3 *db, /* Database handle */ 3318 const void *zSql, /* SQL statement, UTF-16 encoded */ 3319 int nByte, /* Maximum length of zSql in bytes. */ 3320 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3321 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3322); 3323SQLITE_API int SQLITE_STDCALL sqlite3_prepare16_v2( 3324 sqlite3 *db, /* Database handle */ 3325 const void *zSql, /* SQL statement, UTF-16 encoded */ 3326 int nByte, /* Maximum length of zSql in bytes. */ 3327 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3328 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3329); 3330 3331/* 3332** CAPI3REF: Retrieving Statement SQL 3333** METHOD: sqlite3_stmt 3334** 3335** ^This interface can be used to retrieve a saved copy of the original 3336** SQL text used to create a [prepared statement] if that statement was 3337** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3338*/ 3339SQLITE_API const char *SQLITE_STDCALL sqlite3_sql(sqlite3_stmt *pStmt); 3340 3341/* 3342** CAPI3REF: Determine If An SQL Statement Writes The Database 3343** METHOD: sqlite3_stmt 3344** 3345** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3346** and only if the [prepared statement] X makes no direct changes to 3347** the content of the database file. 3348** 3349** Note that [application-defined SQL functions] or 3350** [virtual tables] might change the database indirectly as a side effect. 3351** ^(For example, if an application defines a function "eval()" that 3352** calls [sqlite3_exec()], then the following SQL statement would 3353** change the database file through side-effects: 3354** 3355** <blockquote><pre> 3356** SELECT eval('DELETE FROM t1') FROM t2; 3357** </pre></blockquote> 3358** 3359** But because the [SELECT] statement does not change the database file 3360** directly, sqlite3_stmt_readonly() would still return true.)^ 3361** 3362** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3363** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3364** since the statements themselves do not actually modify the database but 3365** rather they control the timing of when other statements modify the 3366** database. ^The [ATTACH] and [DETACH] statements also cause 3367** sqlite3_stmt_readonly() to return true since, while those statements 3368** change the configuration of a database connection, they do not make 3369** changes to the content of the database files on disk. 3370*/ 3371SQLITE_API int SQLITE_STDCALL sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3372 3373/* 3374** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3375** METHOD: sqlite3_stmt 3376** 3377** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3378** [prepared statement] S has been stepped at least once using 3379** [sqlite3_step(S)] but has neither run to completion (returned 3380** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3381** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3382** interface returns false if S is a NULL pointer. If S is not a 3383** NULL pointer and is not a pointer to a valid [prepared statement] 3384** object, then the behavior is undefined and probably undesirable. 3385** 3386** This interface can be used in combination [sqlite3_next_stmt()] 3387** to locate all prepared statements associated with a database 3388** connection that are in need of being reset. This can be used, 3389** for example, in diagnostic routines to search for prepared 3390** statements that are holding a transaction open. 3391*/ 3392SQLITE_API int SQLITE_STDCALL sqlite3_stmt_busy(sqlite3_stmt*); 3393 3394/* 3395** CAPI3REF: Dynamically Typed Value Object 3396** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3397** 3398** SQLite uses the sqlite3_value object to represent all values 3399** that can be stored in a database table. SQLite uses dynamic typing 3400** for the values it stores. ^Values stored in sqlite3_value objects 3401** can be integers, floating point values, strings, BLOBs, or NULL. 3402** 3403** An sqlite3_value object may be either "protected" or "unprotected". 3404** Some interfaces require a protected sqlite3_value. Other interfaces 3405** will accept either a protected or an unprotected sqlite3_value. 3406** Every interface that accepts sqlite3_value arguments specifies 3407** whether or not it requires a protected sqlite3_value. The 3408** [sqlite3_value_dup()] interface can be used to construct a new 3409** protected sqlite3_value from an unprotected sqlite3_value. 3410** 3411** The terms "protected" and "unprotected" refer to whether or not 3412** a mutex is held. An internal mutex is held for a protected 3413** sqlite3_value object but no mutex is held for an unprotected 3414** sqlite3_value object. If SQLite is compiled to be single-threaded 3415** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3416** or if SQLite is run in one of reduced mutex modes 3417** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3418** then there is no distinction between protected and unprotected 3419** sqlite3_value objects and they can be used interchangeably. However, 3420** for maximum code portability it is recommended that applications 3421** still make the distinction between protected and unprotected 3422** sqlite3_value objects even when not strictly required. 3423** 3424** ^The sqlite3_value objects that are passed as parameters into the 3425** implementation of [application-defined SQL functions] are protected. 3426** ^The sqlite3_value object returned by 3427** [sqlite3_column_value()] is unprotected. 3428** Unprotected sqlite3_value objects may only be used with 3429** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3430** The [sqlite3_value_blob | sqlite3_value_type()] family of 3431** interfaces require protected sqlite3_value objects. 3432*/ 3433typedef struct Mem sqlite3_value; 3434 3435/* 3436** CAPI3REF: SQL Function Context Object 3437** 3438** The context in which an SQL function executes is stored in an 3439** sqlite3_context object. ^A pointer to an sqlite3_context object 3440** is always first parameter to [application-defined SQL functions]. 3441** The application-defined SQL function implementation will pass this 3442** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3443** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3444** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3445** and/or [sqlite3_set_auxdata()]. 3446*/ 3447typedef struct sqlite3_context sqlite3_context; 3448 3449/* 3450** CAPI3REF: Binding Values To Prepared Statements 3451** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3452** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3453** METHOD: sqlite3_stmt 3454** 3455** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3456** literals may be replaced by a [parameter] that matches one of following 3457** templates: 3458** 3459** <ul> 3460** <li> ? 3461** <li> ?NNN 3462** <li> :VVV 3463** <li> @VVV 3464** <li> $VVV 3465** </ul> 3466** 3467** In the templates above, NNN represents an integer literal, 3468** and VVV represents an alphanumeric identifier.)^ ^The values of these 3469** parameters (also called "host parameter names" or "SQL parameters") 3470** can be set using the sqlite3_bind_*() routines defined here. 3471** 3472** ^The first argument to the sqlite3_bind_*() routines is always 3473** a pointer to the [sqlite3_stmt] object returned from 3474** [sqlite3_prepare_v2()] or its variants. 3475** 3476** ^The second argument is the index of the SQL parameter to be set. 3477** ^The leftmost SQL parameter has an index of 1. ^When the same named 3478** SQL parameter is used more than once, second and subsequent 3479** occurrences have the same index as the first occurrence. 3480** ^The index for named parameters can be looked up using the 3481** [sqlite3_bind_parameter_index()] API if desired. ^The index 3482** for "?NNN" parameters is the value of NNN. 3483** ^The NNN value must be between 1 and the [sqlite3_limit()] 3484** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3485** 3486** ^The third argument is the value to bind to the parameter. 3487** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3488** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3489** is ignored and the end result is the same as sqlite3_bind_null(). 3490** 3491** ^(In those routines that have a fourth argument, its value is the 3492** number of bytes in the parameter. To be clear: the value is the 3493** number of <u>bytes</u> in the value, not the number of characters.)^ 3494** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3495** is negative, then the length of the string is 3496** the number of bytes up to the first zero terminator. 3497** If the fourth parameter to sqlite3_bind_blob() is negative, then 3498** the behavior is undefined. 3499** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3500** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3501** that parameter must be the byte offset 3502** where the NUL terminator would occur assuming the string were NUL 3503** terminated. If any NUL characters occur at byte offsets less than 3504** the value of the fourth parameter then the resulting string value will 3505** contain embedded NULs. The result of expressions involving strings 3506** with embedded NULs is undefined. 3507** 3508** ^The fifth argument to the BLOB and string binding interfaces 3509** is a destructor used to dispose of the BLOB or 3510** string after SQLite has finished with it. ^The destructor is called 3511** to dispose of the BLOB or string even if the call to bind API fails. 3512** ^If the fifth argument is 3513** the special value [SQLITE_STATIC], then SQLite assumes that the 3514** information is in static, unmanaged space and does not need to be freed. 3515** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3516** SQLite makes its own private copy of the data immediately, before 3517** the sqlite3_bind_*() routine returns. 3518** 3519** ^The sixth argument to sqlite3_bind_text64() must be one of 3520** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3521** to specify the encoding of the text in the third parameter. If 3522** the sixth argument to sqlite3_bind_text64() is not one of the 3523** allowed values shown above, or if the text encoding is different 3524** from the encoding specified by the sixth parameter, then the behavior 3525** is undefined. 3526** 3527** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3528** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3529** (just an integer to hold its size) while it is being processed. 3530** Zeroblobs are intended to serve as placeholders for BLOBs whose 3531** content is later written using 3532** [sqlite3_blob_open | incremental BLOB I/O] routines. 3533** ^A negative value for the zeroblob results in a zero-length BLOB. 3534** 3535** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3536** for the [prepared statement] or with a prepared statement for which 3537** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3538** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3539** routine is passed a [prepared statement] that has been finalized, the 3540** result is undefined and probably harmful. 3541** 3542** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3543** ^Unbound parameters are interpreted as NULL. 3544** 3545** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3546** [error code] if anything goes wrong. 3547** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3548** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3549** [SQLITE_MAX_LENGTH]. 3550** ^[SQLITE_RANGE] is returned if the parameter 3551** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3552** 3553** See also: [sqlite3_bind_parameter_count()], 3554** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3555*/ 3556SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3557SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3558 void(*)(void*)); 3559SQLITE_API int SQLITE_STDCALL sqlite3_bind_double(sqlite3_stmt*, int, double); 3560SQLITE_API int SQLITE_STDCALL sqlite3_bind_int(sqlite3_stmt*, int, int); 3561SQLITE_API int SQLITE_STDCALL sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3562SQLITE_API int SQLITE_STDCALL sqlite3_bind_null(sqlite3_stmt*, int); 3563SQLITE_API int SQLITE_STDCALL sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3564SQLITE_API int SQLITE_STDCALL sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3565SQLITE_API int SQLITE_STDCALL sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3566 void(*)(void*), unsigned char encoding); 3567SQLITE_API int SQLITE_STDCALL sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3568SQLITE_API int SQLITE_STDCALL sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3569SQLITE_API int SQLITE_STDCALL sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3570 3571/* 3572** CAPI3REF: Number Of SQL Parameters 3573** METHOD: sqlite3_stmt 3574** 3575** ^This routine can be used to find the number of [SQL parameters] 3576** in a [prepared statement]. SQL parameters are tokens of the 3577** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3578** placeholders for values that are [sqlite3_bind_blob | bound] 3579** to the parameters at a later time. 3580** 3581** ^(This routine actually returns the index of the largest (rightmost) 3582** parameter. For all forms except ?NNN, this will correspond to the 3583** number of unique parameters. If parameters of the ?NNN form are used, 3584** there may be gaps in the list.)^ 3585** 3586** See also: [sqlite3_bind_blob|sqlite3_bind()], 3587** [sqlite3_bind_parameter_name()], and 3588** [sqlite3_bind_parameter_index()]. 3589*/ 3590SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_count(sqlite3_stmt*); 3591 3592/* 3593** CAPI3REF: Name Of A Host Parameter 3594** METHOD: sqlite3_stmt 3595** 3596** ^The sqlite3_bind_parameter_name(P,N) interface returns 3597** the name of the N-th [SQL parameter] in the [prepared statement] P. 3598** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3599** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3600** respectively. 3601** In other words, the initial ":" or "$" or "@" or "?" 3602** is included as part of the name.)^ 3603** ^Parameters of the form "?" without a following integer have no name 3604** and are referred to as "nameless" or "anonymous parameters". 3605** 3606** ^The first host parameter has an index of 1, not 0. 3607** 3608** ^If the value N is out of range or if the N-th parameter is 3609** nameless, then NULL is returned. ^The returned string is 3610** always in UTF-8 encoding even if the named parameter was 3611** originally specified as UTF-16 in [sqlite3_prepare16()] or 3612** [sqlite3_prepare16_v2()]. 3613** 3614** See also: [sqlite3_bind_blob|sqlite3_bind()], 3615** [sqlite3_bind_parameter_count()], and 3616** [sqlite3_bind_parameter_index()]. 3617*/ 3618SQLITE_API const char *SQLITE_STDCALL sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3619 3620/* 3621** CAPI3REF: Index Of A Parameter With A Given Name 3622** METHOD: sqlite3_stmt 3623** 3624** ^Return the index of an SQL parameter given its name. ^The 3625** index value returned is suitable for use as the second 3626** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3627** is returned if no matching parameter is found. ^The parameter 3628** name must be given in UTF-8 even if the original statement 3629** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3630** 3631** See also: [sqlite3_bind_blob|sqlite3_bind()], 3632** [sqlite3_bind_parameter_count()], and 3633** [sqlite3_bind_parameter_name()]. 3634*/ 3635SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3636 3637/* 3638** CAPI3REF: Reset All Bindings On A Prepared Statement 3639** METHOD: sqlite3_stmt 3640** 3641** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3642** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3643** ^Use this routine to reset all host parameters to NULL. 3644*/ 3645SQLITE_API int SQLITE_STDCALL sqlite3_clear_bindings(sqlite3_stmt*); 3646 3647/* 3648** CAPI3REF: Number Of Columns In A Result Set 3649** METHOD: sqlite3_stmt 3650** 3651** ^Return the number of columns in the result set returned by the 3652** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3653** statement that does not return data (for example an [UPDATE]). 3654** 3655** See also: [sqlite3_data_count()] 3656*/ 3657SQLITE_API int SQLITE_STDCALL sqlite3_column_count(sqlite3_stmt *pStmt); 3658 3659/* 3660** CAPI3REF: Column Names In A Result Set 3661** METHOD: sqlite3_stmt 3662** 3663** ^These routines return the name assigned to a particular column 3664** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3665** interface returns a pointer to a zero-terminated UTF-8 string 3666** and sqlite3_column_name16() returns a pointer to a zero-terminated 3667** UTF-16 string. ^The first parameter is the [prepared statement] 3668** that implements the [SELECT] statement. ^The second parameter is the 3669** column number. ^The leftmost column is number 0. 3670** 3671** ^The returned string pointer is valid until either the [prepared statement] 3672** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3673** reprepared by the first call to [sqlite3_step()] for a particular run 3674** or until the next call to 3675** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3676** 3677** ^If sqlite3_malloc() fails during the processing of either routine 3678** (for example during a conversion from UTF-8 to UTF-16) then a 3679** NULL pointer is returned. 3680** 3681** ^The name of a result column is the value of the "AS" clause for 3682** that column, if there is an AS clause. If there is no AS clause 3683** then the name of the column is unspecified and may change from 3684** one release of SQLite to the next. 3685*/ 3686SQLITE_API const char *SQLITE_STDCALL sqlite3_column_name(sqlite3_stmt*, int N); 3687SQLITE_API const void *SQLITE_STDCALL sqlite3_column_name16(sqlite3_stmt*, int N); 3688 3689/* 3690** CAPI3REF: Source Of Data In A Query Result 3691** METHOD: sqlite3_stmt 3692** 3693** ^These routines provide a means to determine the database, table, and 3694** table column that is the origin of a particular result column in 3695** [SELECT] statement. 3696** ^The name of the database or table or column can be returned as 3697** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3698** the database name, the _table_ routines return the table name, and 3699** the origin_ routines return the column name. 3700** ^The returned string is valid until the [prepared statement] is destroyed 3701** using [sqlite3_finalize()] or until the statement is automatically 3702** reprepared by the first call to [sqlite3_step()] for a particular run 3703** or until the same information is requested 3704** again in a different encoding. 3705** 3706** ^The names returned are the original un-aliased names of the 3707** database, table, and column. 3708** 3709** ^The first argument to these interfaces is a [prepared statement]. 3710** ^These functions return information about the Nth result column returned by 3711** the statement, where N is the second function argument. 3712** ^The left-most column is column 0 for these routines. 3713** 3714** ^If the Nth column returned by the statement is an expression or 3715** subquery and is not a column value, then all of these functions return 3716** NULL. ^These routine might also return NULL if a memory allocation error 3717** occurs. ^Otherwise, they return the name of the attached database, table, 3718** or column that query result column was extracted from. 3719** 3720** ^As with all other SQLite APIs, those whose names end with "16" return 3721** UTF-16 encoded strings and the other functions return UTF-8. 3722** 3723** ^These APIs are only available if the library was compiled with the 3724** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3725** 3726** If two or more threads call one or more of these routines against the same 3727** prepared statement and column at the same time then the results are 3728** undefined. 3729** 3730** If two or more threads call one or more 3731** [sqlite3_column_database_name | column metadata interfaces] 3732** for the same [prepared statement] and result column 3733** at the same time then the results are undefined. 3734*/ 3735SQLITE_API const char *SQLITE_STDCALL sqlite3_column_database_name(sqlite3_stmt*,int); 3736SQLITE_API const void *SQLITE_STDCALL sqlite3_column_database_name16(sqlite3_stmt*,int); 3737SQLITE_API const char *SQLITE_STDCALL sqlite3_column_table_name(sqlite3_stmt*,int); 3738SQLITE_API const void *SQLITE_STDCALL sqlite3_column_table_name16(sqlite3_stmt*,int); 3739SQLITE_API const char *SQLITE_STDCALL sqlite3_column_origin_name(sqlite3_stmt*,int); 3740SQLITE_API const void *SQLITE_STDCALL sqlite3_column_origin_name16(sqlite3_stmt*,int); 3741 3742/* 3743** CAPI3REF: Declared Datatype Of A Query Result 3744** METHOD: sqlite3_stmt 3745** 3746** ^(The first parameter is a [prepared statement]. 3747** If this statement is a [SELECT] statement and the Nth column of the 3748** returned result set of that [SELECT] is a table column (not an 3749** expression or subquery) then the declared type of the table 3750** column is returned.)^ ^If the Nth column of the result set is an 3751** expression or subquery, then a NULL pointer is returned. 3752** ^The returned string is always UTF-8 encoded. 3753** 3754** ^(For example, given the database schema: 3755** 3756** CREATE TABLE t1(c1 VARIANT); 3757** 3758** and the following statement to be compiled: 3759** 3760** SELECT c1 + 1, c1 FROM t1; 3761** 3762** this routine would return the string "VARIANT" for the second result 3763** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3764** 3765** ^SQLite uses dynamic run-time typing. ^So just because a column 3766** is declared to contain a particular type does not mean that the 3767** data stored in that column is of the declared type. SQLite is 3768** strongly typed, but the typing is dynamic not static. ^Type 3769** is associated with individual values, not with the containers 3770** used to hold those values. 3771*/ 3772SQLITE_API const char *SQLITE_STDCALL sqlite3_column_decltype(sqlite3_stmt*,int); 3773SQLITE_API const void *SQLITE_STDCALL sqlite3_column_decltype16(sqlite3_stmt*,int); 3774 3775/* 3776** CAPI3REF: Evaluate An SQL Statement 3777** METHOD: sqlite3_stmt 3778** 3779** After a [prepared statement] has been prepared using either 3780** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3781** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3782** must be called one or more times to evaluate the statement. 3783** 3784** The details of the behavior of the sqlite3_step() interface depend 3785** on whether the statement was prepared using the newer "v2" interface 3786** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3787** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3788** new "v2" interface is recommended for new applications but the legacy 3789** interface will continue to be supported. 3790** 3791** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3792** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3793** ^With the "v2" interface, any of the other [result codes] or 3794** [extended result codes] might be returned as well. 3795** 3796** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3797** database locks it needs to do its job. ^If the statement is a [COMMIT] 3798** or occurs outside of an explicit transaction, then you can retry the 3799** statement. If the statement is not a [COMMIT] and occurs within an 3800** explicit transaction then you should rollback the transaction before 3801** continuing. 3802** 3803** ^[SQLITE_DONE] means that the statement has finished executing 3804** successfully. sqlite3_step() should not be called again on this virtual 3805** machine without first calling [sqlite3_reset()] to reset the virtual 3806** machine back to its initial state. 3807** 3808** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3809** is returned each time a new row of data is ready for processing by the 3810** caller. The values may be accessed using the [column access functions]. 3811** sqlite3_step() is called again to retrieve the next row of data. 3812** 3813** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3814** violation) has occurred. sqlite3_step() should not be called again on 3815** the VM. More information may be found by calling [sqlite3_errmsg()]. 3816** ^With the legacy interface, a more specific error code (for example, 3817** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3818** can be obtained by calling [sqlite3_reset()] on the 3819** [prepared statement]. ^In the "v2" interface, 3820** the more specific error code is returned directly by sqlite3_step(). 3821** 3822** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3823** Perhaps it was called on a [prepared statement] that has 3824** already been [sqlite3_finalize | finalized] or on one that had 3825** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3826** be the case that the same database connection is being used by two or 3827** more threads at the same moment in time. 3828** 3829** For all versions of SQLite up to and including 3.6.23.1, a call to 3830** [sqlite3_reset()] was required after sqlite3_step() returned anything 3831** other than [SQLITE_ROW] before any subsequent invocation of 3832** sqlite3_step(). Failure to reset the prepared statement using 3833** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3834** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3835** calling [sqlite3_reset()] automatically in this circumstance rather 3836** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3837** break because any application that ever receives an SQLITE_MISUSE error 3838** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3839** can be used to restore the legacy behavior. 3840** 3841** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3842** API always returns a generic error code, [SQLITE_ERROR], following any 3843** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3844** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3845** specific [error codes] that better describes the error. 3846** We admit that this is a goofy design. The problem has been fixed 3847** with the "v2" interface. If you prepare all of your SQL statements 3848** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3849** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3850** then the more specific [error codes] are returned directly 3851** by sqlite3_step(). The use of the "v2" interface is recommended. 3852*/ 3853SQLITE_API int SQLITE_STDCALL sqlite3_step(sqlite3_stmt*); 3854 3855/* 3856** CAPI3REF: Number of columns in a result set 3857** METHOD: sqlite3_stmt 3858** 3859** ^The sqlite3_data_count(P) interface returns the number of columns in the 3860** current row of the result set of [prepared statement] P. 3861** ^If prepared statement P does not have results ready to return 3862** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3863** interfaces) then sqlite3_data_count(P) returns 0. 3864** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3865** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3866** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3867** will return non-zero if previous call to [sqlite3_step](P) returned 3868** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3869** where it always returns zero since each step of that multi-step 3870** pragma returns 0 columns of data. 3871** 3872** See also: [sqlite3_column_count()] 3873*/ 3874SQLITE_API int SQLITE_STDCALL sqlite3_data_count(sqlite3_stmt *pStmt); 3875 3876/* 3877** CAPI3REF: Fundamental Datatypes 3878** KEYWORDS: SQLITE_TEXT 3879** 3880** ^(Every value in SQLite has one of five fundamental datatypes: 3881** 3882** <ul> 3883** <li> 64-bit signed integer 3884** <li> 64-bit IEEE floating point number 3885** <li> string 3886** <li> BLOB 3887** <li> NULL 3888** </ul>)^ 3889** 3890** These constants are codes for each of those types. 3891** 3892** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3893** for a completely different meaning. Software that links against both 3894** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3895** SQLITE_TEXT. 3896*/ 3897#define SQLITE_INTEGER 1 3898#define SQLITE_FLOAT 2 3899#define SQLITE_BLOB 4 3900#define SQLITE_NULL 5 3901#ifdef SQLITE_TEXT 3902# undef SQLITE_TEXT 3903#else 3904# define SQLITE_TEXT 3 3905#endif 3906#define SQLITE3_TEXT 3 3907 3908/* 3909** CAPI3REF: Result Values From A Query 3910** KEYWORDS: {column access functions} 3911** METHOD: sqlite3_stmt 3912** 3913** ^These routines return information about a single column of the current 3914** result row of a query. ^In every case the first argument is a pointer 3915** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3916** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3917** and the second argument is the index of the column for which information 3918** should be returned. ^The leftmost column of the result set has the index 0. 3919** ^The number of columns in the result can be determined using 3920** [sqlite3_column_count()]. 3921** 3922** If the SQL statement does not currently point to a valid row, or if the 3923** column index is out of range, the result is undefined. 3924** These routines may only be called when the most recent call to 3925** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3926** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3927** If any of these routines are called after [sqlite3_reset()] or 3928** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3929** something other than [SQLITE_ROW], the results are undefined. 3930** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3931** are called from a different thread while any of these routines 3932** are pending, then the results are undefined. 3933** 3934** ^The sqlite3_column_type() routine returns the 3935** [SQLITE_INTEGER | datatype code] for the initial data type 3936** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3937** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3938** returned by sqlite3_column_type() is only meaningful if no type 3939** conversions have occurred as described below. After a type conversion, 3940** the value returned by sqlite3_column_type() is undefined. Future 3941** versions of SQLite may change the behavior of sqlite3_column_type() 3942** following a type conversion. 3943** 3944** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3945** routine returns the number of bytes in that BLOB or string. 3946** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3947** the string to UTF-8 and then returns the number of bytes. 3948** ^If the result is a numeric value then sqlite3_column_bytes() uses 3949** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3950** the number of bytes in that string. 3951** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3952** 3953** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3954** routine returns the number of bytes in that BLOB or string. 3955** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3956** the string to UTF-16 and then returns the number of bytes. 3957** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3958** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3959** the number of bytes in that string. 3960** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3961** 3962** ^The values returned by [sqlite3_column_bytes()] and 3963** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3964** of the string. ^For clarity: the values returned by 3965** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3966** bytes in the string, not the number of characters. 3967** 3968** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3969** even empty strings, are always zero-terminated. ^The return 3970** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3971** 3972** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 3973** [unprotected sqlite3_value] object. In a multithreaded environment, 3974** an unprotected sqlite3_value object may only be used safely with 3975** [sqlite3_bind_value()] and [sqlite3_result_value()]. 3976** If the [unprotected sqlite3_value] object returned by 3977** [sqlite3_column_value()] is used in any other way, including calls 3978** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3979** or [sqlite3_value_bytes()], the behavior is not threadsafe. 3980** 3981** These routines attempt to convert the value where appropriate. ^For 3982** example, if the internal representation is FLOAT and a text result 3983** is requested, [sqlite3_snprintf()] is used internally to perform the 3984** conversion automatically. ^(The following table details the conversions 3985** that are applied: 3986** 3987** <blockquote> 3988** <table border="1"> 3989** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3990** 3991** <tr><td> NULL <td> INTEGER <td> Result is 0 3992** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3993** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 3994** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 3995** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3996** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3997** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3998** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 3999** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4000** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4001** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4002** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4003** <tr><td> TEXT <td> BLOB <td> No change 4004** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4005** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4006** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4007** </table> 4008** </blockquote>)^ 4009** 4010** Note that when type conversions occur, pointers returned by prior 4011** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4012** sqlite3_column_text16() may be invalidated. 4013** Type conversions and pointer invalidations might occur 4014** in the following cases: 4015** 4016** <ul> 4017** <li> The initial content is a BLOB and sqlite3_column_text() or 4018** sqlite3_column_text16() is called. A zero-terminator might 4019** need to be added to the string.</li> 4020** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4021** sqlite3_column_text16() is called. The content must be converted 4022** to UTF-16.</li> 4023** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4024** sqlite3_column_text() is called. The content must be converted 4025** to UTF-8.</li> 4026** </ul> 4027** 4028** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4029** not invalidate a prior pointer, though of course the content of the buffer 4030** that the prior pointer references will have been modified. Other kinds 4031** of conversion are done in place when it is possible, but sometimes they 4032** are not possible and in those cases prior pointers are invalidated. 4033** 4034** The safest policy is to invoke these routines 4035** in one of the following ways: 4036** 4037** <ul> 4038** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4039** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4040** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4041** </ul> 4042** 4043** In other words, you should call sqlite3_column_text(), 4044** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4045** into the desired format, then invoke sqlite3_column_bytes() or 4046** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4047** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4048** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4049** with calls to sqlite3_column_bytes(). 4050** 4051** ^The pointers returned are valid until a type conversion occurs as 4052** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4053** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4054** and BLOBs is freed automatically. Do <em>not</em> pass the pointers returned 4055** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4056** [sqlite3_free()]. 4057** 4058** ^(If a memory allocation error occurs during the evaluation of any 4059** of these routines, a default value is returned. The default value 4060** is either the integer 0, the floating point number 0.0, or a NULL 4061** pointer. Subsequent calls to [sqlite3_errcode()] will return 4062** [SQLITE_NOMEM].)^ 4063*/ 4064SQLITE_API const void *SQLITE_STDCALL sqlite3_column_blob(sqlite3_stmt*, int iCol); 4065SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4066SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4067SQLITE_API double SQLITE_STDCALL sqlite3_column_double(sqlite3_stmt*, int iCol); 4068SQLITE_API int SQLITE_STDCALL sqlite3_column_int(sqlite3_stmt*, int iCol); 4069SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_column_int64(sqlite3_stmt*, int iCol); 4070SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_column_text(sqlite3_stmt*, int iCol); 4071SQLITE_API const void *SQLITE_STDCALL sqlite3_column_text16(sqlite3_stmt*, int iCol); 4072SQLITE_API int SQLITE_STDCALL sqlite3_column_type(sqlite3_stmt*, int iCol); 4073SQLITE_API sqlite3_value *SQLITE_STDCALL sqlite3_column_value(sqlite3_stmt*, int iCol); 4074 4075/* 4076** CAPI3REF: Destroy A Prepared Statement Object 4077** DESTRUCTOR: sqlite3_stmt 4078** 4079** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4080** ^If the most recent evaluation of the statement encountered no errors 4081** or if the statement is never been evaluated, then sqlite3_finalize() returns 4082** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4083** sqlite3_finalize(S) returns the appropriate [error code] or 4084** [extended error code]. 4085** 4086** ^The sqlite3_finalize(S) routine can be called at any point during 4087** the life cycle of [prepared statement] S: 4088** before statement S is ever evaluated, after 4089** one or more calls to [sqlite3_reset()], or after any call 4090** to [sqlite3_step()] regardless of whether or not the statement has 4091** completed execution. 4092** 4093** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4094** 4095** The application must finalize every [prepared statement] in order to avoid 4096** resource leaks. It is a grievous error for the application to try to use 4097** a prepared statement after it has been finalized. Any use of a prepared 4098** statement after it has been finalized can result in undefined and 4099** undesirable behavior such as segfaults and heap corruption. 4100*/ 4101SQLITE_API int SQLITE_STDCALL sqlite3_finalize(sqlite3_stmt *pStmt); 4102 4103/* 4104** CAPI3REF: Reset A Prepared Statement Object 4105** METHOD: sqlite3_stmt 4106** 4107** The sqlite3_reset() function is called to reset a [prepared statement] 4108** object back to its initial state, ready to be re-executed. 4109** ^Any SQL statement variables that had values bound to them using 4110** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4111** Use [sqlite3_clear_bindings()] to reset the bindings. 4112** 4113** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4114** back to the beginning of its program. 4115** 4116** ^If the most recent call to [sqlite3_step(S)] for the 4117** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4118** or if [sqlite3_step(S)] has never before been called on S, 4119** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4120** 4121** ^If the most recent call to [sqlite3_step(S)] for the 4122** [prepared statement] S indicated an error, then 4123** [sqlite3_reset(S)] returns an appropriate [error code]. 4124** 4125** ^The [sqlite3_reset(S)] interface does not change the values 4126** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4127*/ 4128SQLITE_API int SQLITE_STDCALL sqlite3_reset(sqlite3_stmt *pStmt); 4129 4130/* 4131** CAPI3REF: Create Or Redefine SQL Functions 4132** KEYWORDS: {function creation routines} 4133** KEYWORDS: {application-defined SQL function} 4134** KEYWORDS: {application-defined SQL functions} 4135** METHOD: sqlite3 4136** 4137** ^These functions (collectively known as "function creation routines") 4138** are used to add SQL functions or aggregates or to redefine the behavior 4139** of existing SQL functions or aggregates. The only differences between 4140** these routines are the text encoding expected for 4141** the second parameter (the name of the function being created) 4142** and the presence or absence of a destructor callback for 4143** the application data pointer. 4144** 4145** ^The first parameter is the [database connection] to which the SQL 4146** function is to be added. ^If an application uses more than one database 4147** connection then application-defined SQL functions must be added 4148** to each database connection separately. 4149** 4150** ^The second parameter is the name of the SQL function to be created or 4151** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4152** representation, exclusive of the zero-terminator. ^Note that the name 4153** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4154** ^Any attempt to create a function with a longer name 4155** will result in [SQLITE_MISUSE] being returned. 4156** 4157** ^The third parameter (nArg) 4158** is the number of arguments that the SQL function or 4159** aggregate takes. ^If this parameter is -1, then the SQL function or 4160** aggregate may take any number of arguments between 0 and the limit 4161** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4162** parameter is less than -1 or greater than 127 then the behavior is 4163** undefined. 4164** 4165** ^The fourth parameter, eTextRep, specifies what 4166** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4167** its parameters. The application should set this parameter to 4168** [SQLITE_UTF16LE] if the function implementation invokes 4169** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4170** implementation invokes [sqlite3_value_text16be()] on an input, or 4171** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4172** otherwise. ^The same SQL function may be registered multiple times using 4173** different preferred text encodings, with different implementations for 4174** each encoding. 4175** ^When multiple implementations of the same function are available, SQLite 4176** will pick the one that involves the least amount of data conversion. 4177** 4178** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4179** to signal that the function will always return the same result given 4180** the same inputs within a single SQL statement. Most SQL functions are 4181** deterministic. The built-in [random()] SQL function is an example of a 4182** function that is not deterministic. The SQLite query planner is able to 4183** perform additional optimizations on deterministic functions, so use 4184** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4185** 4186** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4187** function can gain access to this pointer using [sqlite3_user_data()].)^ 4188** 4189** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4190** pointers to C-language functions that implement the SQL function or 4191** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4192** callback only; NULL pointers must be passed as the xStep and xFinal 4193** parameters. ^An aggregate SQL function requires an implementation of xStep 4194** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4195** SQL function or aggregate, pass NULL pointers for all three function 4196** callbacks. 4197** 4198** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4199** then it is destructor for the application data pointer. 4200** The destructor is invoked when the function is deleted, either by being 4201** overloaded or when the database connection closes.)^ 4202** ^The destructor is also invoked if the call to 4203** sqlite3_create_function_v2() fails. 4204** ^When the destructor callback of the tenth parameter is invoked, it 4205** is passed a single argument which is a copy of the application data 4206** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4207** 4208** ^It is permitted to register multiple implementations of the same 4209** functions with the same name but with either differing numbers of 4210** arguments or differing preferred text encodings. ^SQLite will use 4211** the implementation that most closely matches the way in which the 4212** SQL function is used. ^A function implementation with a non-negative 4213** nArg parameter is a better match than a function implementation with 4214** a negative nArg. ^A function where the preferred text encoding 4215** matches the database encoding is a better 4216** match than a function where the encoding is different. 4217** ^A function where the encoding difference is between UTF16le and UTF16be 4218** is a closer match than a function where the encoding difference is 4219** between UTF8 and UTF16. 4220** 4221** ^Built-in functions may be overloaded by new application-defined functions. 4222** 4223** ^An application-defined function is permitted to call other 4224** SQLite interfaces. However, such calls must not 4225** close the database connection nor finalize or reset the prepared 4226** statement in which the function is running. 4227*/ 4228SQLITE_API int SQLITE_STDCALL sqlite3_create_function( 4229 sqlite3 *db, 4230 const char *zFunctionName, 4231 int nArg, 4232 int eTextRep, 4233 void *pApp, 4234 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4235 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4236 void (*xFinal)(sqlite3_context*) 4237); 4238SQLITE_API int SQLITE_STDCALL sqlite3_create_function16( 4239 sqlite3 *db, 4240 const void *zFunctionName, 4241 int nArg, 4242 int eTextRep, 4243 void *pApp, 4244 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4245 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4246 void (*xFinal)(sqlite3_context*) 4247); 4248SQLITE_API int SQLITE_STDCALL sqlite3_create_function_v2( 4249 sqlite3 *db, 4250 const char *zFunctionName, 4251 int nArg, 4252 int eTextRep, 4253 void *pApp, 4254 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4255 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4256 void (*xFinal)(sqlite3_context*), 4257 void(*xDestroy)(void*) 4258); 4259 4260/* 4261** CAPI3REF: Text Encodings 4262** 4263** These constant define integer codes that represent the various 4264** text encodings supported by SQLite. 4265*/ 4266#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4267#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4268#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4269#define SQLITE_UTF16 4 /* Use native byte order */ 4270#define SQLITE_ANY 5 /* Deprecated */ 4271#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4272 4273/* 4274** CAPI3REF: Function Flags 4275** 4276** These constants may be ORed together with the 4277** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4278** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4279** [sqlite3_create_function_v2()]. 4280*/ 4281#define SQLITE_DETERMINISTIC 0x800 4282 4283/* 4284** CAPI3REF: Deprecated Functions 4285** DEPRECATED 4286** 4287** These functions are [deprecated]. In order to maintain 4288** backwards compatibility with older code, these functions continue 4289** to be supported. However, new applications should avoid 4290** the use of these functions. To encourage programmers to avoid 4291** these functions, we will not explain what they do. 4292*/ 4293#ifndef SQLITE_OMIT_DEPRECATED 4294SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_aggregate_count(sqlite3_context*); 4295SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_expired(sqlite3_stmt*); 4296SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4297SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_global_recover(void); 4298SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_thread_cleanup(void); 4299SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4300 void*,sqlite3_int64); 4301#endif 4302 4303/* 4304** CAPI3REF: Obtaining SQL Values 4305** METHOD: sqlite3_value 4306** 4307** The C-language implementation of SQL functions and aggregates uses 4308** this set of interface routines to access the parameter values on 4309** the function or aggregate. 4310** 4311** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4312** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4313** define callbacks that implement the SQL functions and aggregates. 4314** The 3rd parameter to these callbacks is an array of pointers to 4315** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4316** each parameter to the SQL function. These routines are used to 4317** extract values from the [sqlite3_value] objects. 4318** 4319** These routines work only with [protected sqlite3_value] objects. 4320** Any attempt to use these routines on an [unprotected sqlite3_value] 4321** object results in undefined behavior. 4322** 4323** ^These routines work just like the corresponding [column access functions] 4324** except that these routines take a single [protected sqlite3_value] object 4325** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4326** 4327** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4328** in the native byte-order of the host machine. ^The 4329** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4330** extract UTF-16 strings as big-endian and little-endian respectively. 4331** 4332** ^(The sqlite3_value_numeric_type() interface attempts to apply 4333** numeric affinity to the value. This means that an attempt is 4334** made to convert the value to an integer or floating point. If 4335** such a conversion is possible without loss of information (in other 4336** words, if the value is a string that looks like a number) 4337** then the conversion is performed. Otherwise no conversion occurs. 4338** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4339** 4340** Please pay particular attention to the fact that the pointer returned 4341** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4342** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4343** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4344** or [sqlite3_value_text16()]. 4345** 4346** These routines must be called from the same thread as 4347** the SQL function that supplied the [sqlite3_value*] parameters. 4348*/ 4349SQLITE_API const void *SQLITE_STDCALL sqlite3_value_blob(sqlite3_value*); 4350SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes(sqlite3_value*); 4351SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes16(sqlite3_value*); 4352SQLITE_API double SQLITE_STDCALL sqlite3_value_double(sqlite3_value*); 4353SQLITE_API int SQLITE_STDCALL sqlite3_value_int(sqlite3_value*); 4354SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_value_int64(sqlite3_value*); 4355SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_value_text(sqlite3_value*); 4356SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16(sqlite3_value*); 4357SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16le(sqlite3_value*); 4358SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16be(sqlite3_value*); 4359SQLITE_API int SQLITE_STDCALL sqlite3_value_type(sqlite3_value*); 4360SQLITE_API int SQLITE_STDCALL sqlite3_value_numeric_type(sqlite3_value*); 4361 4362/* 4363** CAPI3REF: Finding The Subtype Of SQL Values 4364** METHOD: sqlite3_value 4365** 4366** The sqlite3_value_subtype(V) function returns the subtype for 4367** an [application-defined SQL function] argument V. The subtype 4368** information can be used to pass a limited amount of context from 4369** one SQL function to another. Use the [sqlite3_result_subtype()] 4370** routine to set the subtype for the return value of an SQL function. 4371** 4372** SQLite makes no use of subtype itself. It merely passes the subtype 4373** from the result of one [application-defined SQL function] into the 4374** input of another. 4375*/ 4376SQLITE_API unsigned int SQLITE_STDCALL sqlite3_value_subtype(sqlite3_value*); 4377 4378/* 4379** CAPI3REF: Copy And Free SQL Values 4380** METHOD: sqlite3_value 4381** 4382** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4383** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4384** is a [protected sqlite3_value] object even if the input is not. 4385** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4386** memory allocation fails. 4387** 4388** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4389** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4390** then sqlite3_value_free(V) is a harmless no-op. 4391*/ 4392SQLITE_API SQLITE_EXPERIMENTAL sqlite3_value *SQLITE_STDCALL sqlite3_value_dup(const sqlite3_value*); 4393SQLITE_API SQLITE_EXPERIMENTAL void SQLITE_STDCALL sqlite3_value_free(sqlite3_value*); 4394 4395/* 4396** CAPI3REF: Obtain Aggregate Function Context 4397** METHOD: sqlite3_context 4398** 4399** Implementations of aggregate SQL functions use this 4400** routine to allocate memory for storing their state. 4401** 4402** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4403** for a particular aggregate function, SQLite 4404** allocates N of memory, zeroes out that memory, and returns a pointer 4405** to the new memory. ^On second and subsequent calls to 4406** sqlite3_aggregate_context() for the same aggregate function instance, 4407** the same buffer is returned. Sqlite3_aggregate_context() is normally 4408** called once for each invocation of the xStep callback and then one 4409** last time when the xFinal callback is invoked. ^(When no rows match 4410** an aggregate query, the xStep() callback of the aggregate function 4411** implementation is never called and xFinal() is called exactly once. 4412** In those cases, sqlite3_aggregate_context() might be called for the 4413** first time from within xFinal().)^ 4414** 4415** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4416** when first called if N is less than or equal to zero or if a memory 4417** allocate error occurs. 4418** 4419** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4420** determined by the N parameter on first successful call. Changing the 4421** value of N in subsequent call to sqlite3_aggregate_context() within 4422** the same aggregate function instance will not resize the memory 4423** allocation.)^ Within the xFinal callback, it is customary to set 4424** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4425** pointless memory allocations occur. 4426** 4427** ^SQLite automatically frees the memory allocated by 4428** sqlite3_aggregate_context() when the aggregate query concludes. 4429** 4430** The first parameter must be a copy of the 4431** [sqlite3_context | SQL function context] that is the first parameter 4432** to the xStep or xFinal callback routine that implements the aggregate 4433** function. 4434** 4435** This routine must be called from the same thread in which 4436** the aggregate SQL function is running. 4437*/ 4438SQLITE_API void *SQLITE_STDCALL sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4439 4440/* 4441** CAPI3REF: User Data For Functions 4442** METHOD: sqlite3_context 4443** 4444** ^The sqlite3_user_data() interface returns a copy of 4445** the pointer that was the pUserData parameter (the 5th parameter) 4446** of the [sqlite3_create_function()] 4447** and [sqlite3_create_function16()] routines that originally 4448** registered the application defined function. 4449** 4450** This routine must be called from the same thread in which 4451** the application-defined function is running. 4452*/ 4453SQLITE_API void *SQLITE_STDCALL sqlite3_user_data(sqlite3_context*); 4454 4455/* 4456** CAPI3REF: Database Connection For Functions 4457** METHOD: sqlite3_context 4458** 4459** ^The sqlite3_context_db_handle() interface returns a copy of 4460** the pointer to the [database connection] (the 1st parameter) 4461** of the [sqlite3_create_function()] 4462** and [sqlite3_create_function16()] routines that originally 4463** registered the application defined function. 4464*/ 4465SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_context_db_handle(sqlite3_context*); 4466 4467/* 4468** CAPI3REF: Function Auxiliary Data 4469** METHOD: sqlite3_context 4470** 4471** These functions may be used by (non-aggregate) SQL functions to 4472** associate metadata with argument values. If the same value is passed to 4473** multiple invocations of the same SQL function during query execution, under 4474** some circumstances the associated metadata may be preserved. An example 4475** of where this might be useful is in a regular-expression matching 4476** function. The compiled version of the regular expression can be stored as 4477** metadata associated with the pattern string. 4478** Then as long as the pattern string remains the same, 4479** the compiled regular expression can be reused on multiple 4480** invocations of the same function. 4481** 4482** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4483** associated by the sqlite3_set_auxdata() function with the Nth argument 4484** value to the application-defined function. ^If there is no metadata 4485** associated with the function argument, this sqlite3_get_auxdata() interface 4486** returns a NULL pointer. 4487** 4488** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4489** argument of the application-defined function. ^Subsequent 4490** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4491** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4492** NULL if the metadata has been discarded. 4493** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4494** SQLite will invoke the destructor function X with parameter P exactly 4495** once, when the metadata is discarded. 4496** SQLite is free to discard the metadata at any time, including: <ul> 4497** <li> when the corresponding function parameter changes, or 4498** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4499** SQL statement, or 4500** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or 4501** <li> during the original sqlite3_set_auxdata() call when a memory 4502** allocation error occurs. </ul>)^ 4503** 4504** Note the last bullet in particular. The destructor X in 4505** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4506** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4507** should be called near the end of the function implementation and the 4508** function implementation should not make any use of P after 4509** sqlite3_set_auxdata() has been called. 4510** 4511** ^(In practice, metadata is preserved between function calls for 4512** function parameters that are compile-time constants, including literal 4513** values and [parameters] and expressions composed from the same.)^ 4514** 4515** These routines must be called from the same thread in which 4516** the SQL function is running. 4517*/ 4518SQLITE_API void *SQLITE_STDCALL sqlite3_get_auxdata(sqlite3_context*, int N); 4519SQLITE_API void SQLITE_STDCALL sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4520 4521 4522/* 4523** CAPI3REF: Constants Defining Special Destructor Behavior 4524** 4525** These are special values for the destructor that is passed in as the 4526** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4527** argument is SQLITE_STATIC, it means that the content pointer is constant 4528** and will never change. It does not need to be destroyed. ^The 4529** SQLITE_TRANSIENT value means that the content will likely change in 4530** the near future and that SQLite should make its own private copy of 4531** the content before returning. 4532** 4533** The typedef is necessary to work around problems in certain 4534** C++ compilers. 4535*/ 4536typedef void (*sqlite3_destructor_type)(void*); 4537#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4538#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4539 4540/* 4541** CAPI3REF: Setting The Result Of An SQL Function 4542** METHOD: sqlite3_context 4543** 4544** These routines are used by the xFunc or xFinal callbacks that 4545** implement SQL functions and aggregates. See 4546** [sqlite3_create_function()] and [sqlite3_create_function16()] 4547** for additional information. 4548** 4549** These functions work very much like the [parameter binding] family of 4550** functions used to bind values to host parameters in prepared statements. 4551** Refer to the [SQL parameter] documentation for additional information. 4552** 4553** ^The sqlite3_result_blob() interface sets the result from 4554** an application-defined function to be the BLOB whose content is pointed 4555** to by the second parameter and which is N bytes long where N is the 4556** third parameter. 4557** 4558** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 4559** interfaces set the result of the application-defined function to be 4560** a BLOB containing all zero bytes and N bytes in size. 4561** 4562** ^The sqlite3_result_double() interface sets the result from 4563** an application-defined function to be a floating point value specified 4564** by its 2nd argument. 4565** 4566** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4567** cause the implemented SQL function to throw an exception. 4568** ^SQLite uses the string pointed to by the 4569** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4570** as the text of an error message. ^SQLite interprets the error 4571** message string from sqlite3_result_error() as UTF-8. ^SQLite 4572** interprets the string from sqlite3_result_error16() as UTF-16 in native 4573** byte order. ^If the third parameter to sqlite3_result_error() 4574** or sqlite3_result_error16() is negative then SQLite takes as the error 4575** message all text up through the first zero character. 4576** ^If the third parameter to sqlite3_result_error() or 4577** sqlite3_result_error16() is non-negative then SQLite takes that many 4578** bytes (not characters) from the 2nd parameter as the error message. 4579** ^The sqlite3_result_error() and sqlite3_result_error16() 4580** routines make a private copy of the error message text before 4581** they return. Hence, the calling function can deallocate or 4582** modify the text after they return without harm. 4583** ^The sqlite3_result_error_code() function changes the error code 4584** returned by SQLite as a result of an error in a function. ^By default, 4585** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4586** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4587** 4588** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4589** error indicating that a string or BLOB is too long to represent. 4590** 4591** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4592** error indicating that a memory allocation failed. 4593** 4594** ^The sqlite3_result_int() interface sets the return value 4595** of the application-defined function to be the 32-bit signed integer 4596** value given in the 2nd argument. 4597** ^The sqlite3_result_int64() interface sets the return value 4598** of the application-defined function to be the 64-bit signed integer 4599** value given in the 2nd argument. 4600** 4601** ^The sqlite3_result_null() interface sets the return value 4602** of the application-defined function to be NULL. 4603** 4604** ^The sqlite3_result_text(), sqlite3_result_text16(), 4605** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4606** set the return value of the application-defined function to be 4607** a text string which is represented as UTF-8, UTF-16 native byte order, 4608** UTF-16 little endian, or UTF-16 big endian, respectively. 4609** ^The sqlite3_result_text64() interface sets the return value of an 4610** application-defined function to be a text string in an encoding 4611** specified by the fifth (and last) parameter, which must be one 4612** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 4613** ^SQLite takes the text result from the application from 4614** the 2nd parameter of the sqlite3_result_text* interfaces. 4615** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4616** is negative, then SQLite takes result text from the 2nd parameter 4617** through the first zero character. 4618** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4619** is non-negative, then as many bytes (not characters) of the text 4620** pointed to by the 2nd parameter are taken as the application-defined 4621** function result. If the 3rd parameter is non-negative, then it 4622** must be the byte offset into the string where the NUL terminator would 4623** appear if the string where NUL terminated. If any NUL characters occur 4624** in the string at a byte offset that is less than the value of the 3rd 4625** parameter, then the resulting string will contain embedded NULs and the 4626** result of expressions operating on strings with embedded NULs is undefined. 4627** ^If the 4th parameter to the sqlite3_result_text* interfaces 4628** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4629** function as the destructor on the text or BLOB result when it has 4630** finished using that result. 4631** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4632** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4633** assumes that the text or BLOB result is in constant space and does not 4634** copy the content of the parameter nor call a destructor on the content 4635** when it has finished using that result. 4636** ^If the 4th parameter to the sqlite3_result_text* interfaces 4637** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4638** then SQLite makes a copy of the result into space obtained from 4639** from [sqlite3_malloc()] before it returns. 4640** 4641** ^The sqlite3_result_value() interface sets the result of 4642** the application-defined function to be a copy of the 4643** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4644** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4645** so that the [sqlite3_value] specified in the parameter may change or 4646** be deallocated after sqlite3_result_value() returns without harm. 4647** ^A [protected sqlite3_value] object may always be used where an 4648** [unprotected sqlite3_value] object is required, so either 4649** kind of [sqlite3_value] object can be used with this interface. 4650** 4651** If these routines are called from within the different thread 4652** than the one containing the application-defined function that received 4653** the [sqlite3_context] pointer, the results are undefined. 4654*/ 4655SQLITE_API void SQLITE_STDCALL sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4656SQLITE_API void SQLITE_STDCALL sqlite3_result_blob64(sqlite3_context*,const void*, 4657 sqlite3_uint64,void(*)(void*)); 4658SQLITE_API void SQLITE_STDCALL sqlite3_result_double(sqlite3_context*, double); 4659SQLITE_API void SQLITE_STDCALL sqlite3_result_error(sqlite3_context*, const char*, int); 4660SQLITE_API void SQLITE_STDCALL sqlite3_result_error16(sqlite3_context*, const void*, int); 4661SQLITE_API void SQLITE_STDCALL sqlite3_result_error_toobig(sqlite3_context*); 4662SQLITE_API void SQLITE_STDCALL sqlite3_result_error_nomem(sqlite3_context*); 4663SQLITE_API void SQLITE_STDCALL sqlite3_result_error_code(sqlite3_context*, int); 4664SQLITE_API void SQLITE_STDCALL sqlite3_result_int(sqlite3_context*, int); 4665SQLITE_API void SQLITE_STDCALL sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4666SQLITE_API void SQLITE_STDCALL sqlite3_result_null(sqlite3_context*); 4667SQLITE_API void SQLITE_STDCALL sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4668SQLITE_API void SQLITE_STDCALL sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 4669 void(*)(void*), unsigned char encoding); 4670SQLITE_API void SQLITE_STDCALL sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4671SQLITE_API void SQLITE_STDCALL sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4672SQLITE_API void SQLITE_STDCALL sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4673SQLITE_API void SQLITE_STDCALL sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4674SQLITE_API void SQLITE_STDCALL sqlite3_result_zeroblob(sqlite3_context*, int n); 4675SQLITE_API int SQLITE_STDCALL sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 4676 4677 4678/* 4679** CAPI3REF: Setting The Subtype Of An SQL Function 4680** METHOD: sqlite3_context 4681** 4682** The sqlite3_result_subtype(C,T) function causes the subtype of 4683** the result from the [application-defined SQL function] with 4684** [sqlite3_context] C to be the value T. Only the lower 8 bits 4685** of the subtype T are preserved in current versions of SQLite; 4686** higher order bits are discarded. 4687** The number of subtype bytes preserved by SQLite might increase 4688** in future releases of SQLite. 4689*/ 4690SQLITE_API void SQLITE_STDCALL sqlite3_result_subtype(sqlite3_context*,unsigned int); 4691 4692/* 4693** CAPI3REF: Define New Collating Sequences 4694** METHOD: sqlite3 4695** 4696** ^These functions add, remove, or modify a [collation] associated 4697** with the [database connection] specified as the first argument. 4698** 4699** ^The name of the collation is a UTF-8 string 4700** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4701** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4702** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4703** considered to be the same name. 4704** 4705** ^(The third argument (eTextRep) must be one of the constants: 4706** <ul> 4707** <li> [SQLITE_UTF8], 4708** <li> [SQLITE_UTF16LE], 4709** <li> [SQLITE_UTF16BE], 4710** <li> [SQLITE_UTF16], or 4711** <li> [SQLITE_UTF16_ALIGNED]. 4712** </ul>)^ 4713** ^The eTextRep argument determines the encoding of strings passed 4714** to the collating function callback, xCallback. 4715** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4716** force strings to be UTF16 with native byte order. 4717** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4718** on an even byte address. 4719** 4720** ^The fourth argument, pArg, is an application data pointer that is passed 4721** through as the first argument to the collating function callback. 4722** 4723** ^The fifth argument, xCallback, is a pointer to the collating function. 4724** ^Multiple collating functions can be registered using the same name but 4725** with different eTextRep parameters and SQLite will use whichever 4726** function requires the least amount of data transformation. 4727** ^If the xCallback argument is NULL then the collating function is 4728** deleted. ^When all collating functions having the same name are deleted, 4729** that collation is no longer usable. 4730** 4731** ^The collating function callback is invoked with a copy of the pArg 4732** application data pointer and with two strings in the encoding specified 4733** by the eTextRep argument. The collating function must return an 4734** integer that is negative, zero, or positive 4735** if the first string is less than, equal to, or greater than the second, 4736** respectively. A collating function must always return the same answer 4737** given the same inputs. If two or more collating functions are registered 4738** to the same collation name (using different eTextRep values) then all 4739** must give an equivalent answer when invoked with equivalent strings. 4740** The collating function must obey the following properties for all 4741** strings A, B, and C: 4742** 4743** <ol> 4744** <li> If A==B then B==A. 4745** <li> If A==B and B==C then A==C. 4746** <li> If A<B THEN B>A. 4747** <li> If A<B and B<C then A<C. 4748** </ol> 4749** 4750** If a collating function fails any of the above constraints and that 4751** collating function is registered and used, then the behavior of SQLite 4752** is undefined. 4753** 4754** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4755** with the addition that the xDestroy callback is invoked on pArg when 4756** the collating function is deleted. 4757** ^Collating functions are deleted when they are overridden by later 4758** calls to the collation creation functions or when the 4759** [database connection] is closed using [sqlite3_close()]. 4760** 4761** ^The xDestroy callback is <u>not</u> called if the 4762** sqlite3_create_collation_v2() function fails. Applications that invoke 4763** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4764** check the return code and dispose of the application data pointer 4765** themselves rather than expecting SQLite to deal with it for them. 4766** This is different from every other SQLite interface. The inconsistency 4767** is unfortunate but cannot be changed without breaking backwards 4768** compatibility. 4769** 4770** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4771*/ 4772SQLITE_API int SQLITE_STDCALL sqlite3_create_collation( 4773 sqlite3*, 4774 const char *zName, 4775 int eTextRep, 4776 void *pArg, 4777 int(*xCompare)(void*,int,const void*,int,const void*) 4778); 4779SQLITE_API int SQLITE_STDCALL sqlite3_create_collation_v2( 4780 sqlite3*, 4781 const char *zName, 4782 int eTextRep, 4783 void *pArg, 4784 int(*xCompare)(void*,int,const void*,int,const void*), 4785 void(*xDestroy)(void*) 4786); 4787SQLITE_API int SQLITE_STDCALL sqlite3_create_collation16( 4788 sqlite3*, 4789 const void *zName, 4790 int eTextRep, 4791 void *pArg, 4792 int(*xCompare)(void*,int,const void*,int,const void*) 4793); 4794 4795/* 4796** CAPI3REF: Collation Needed Callbacks 4797** METHOD: sqlite3 4798** 4799** ^To avoid having to register all collation sequences before a database 4800** can be used, a single callback function may be registered with the 4801** [database connection] to be invoked whenever an undefined collation 4802** sequence is required. 4803** 4804** ^If the function is registered using the sqlite3_collation_needed() API, 4805** then it is passed the names of undefined collation sequences as strings 4806** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4807** the names are passed as UTF-16 in machine native byte order. 4808** ^A call to either function replaces the existing collation-needed callback. 4809** 4810** ^(When the callback is invoked, the first argument passed is a copy 4811** of the second argument to sqlite3_collation_needed() or 4812** sqlite3_collation_needed16(). The second argument is the database 4813** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4814** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4815** sequence function required. The fourth parameter is the name of the 4816** required collation sequence.)^ 4817** 4818** The callback function should register the desired collation using 4819** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4820** [sqlite3_create_collation_v2()]. 4821*/ 4822SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed( 4823 sqlite3*, 4824 void*, 4825 void(*)(void*,sqlite3*,int eTextRep,const char*) 4826); 4827SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed16( 4828 sqlite3*, 4829 void*, 4830 void(*)(void*,sqlite3*,int eTextRep,const void*) 4831); 4832 4833#ifdef SQLITE_HAS_CODEC 4834/* 4835** Specify the key for an encrypted database. This routine should be 4836** called right after sqlite3_open(). 4837** 4838** The code to implement this API is not available in the public release 4839** of SQLite. 4840*/ 4841SQLITE_API int SQLITE_STDCALL sqlite3_key( 4842 sqlite3 *db, /* Database to be rekeyed */ 4843 const void *pKey, int nKey /* The key */ 4844); 4845SQLITE_API int SQLITE_STDCALL sqlite3_key_v2( 4846 sqlite3 *db, /* Database to be rekeyed */ 4847 const char *zDbName, /* Name of the database */ 4848 const void *pKey, int nKey /* The key */ 4849); 4850 4851/* 4852** Change the key on an open database. If the current database is not 4853** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4854** database is decrypted. 4855** 4856** The code to implement this API is not available in the public release 4857** of SQLite. 4858*/ 4859SQLITE_API int SQLITE_STDCALL sqlite3_rekey( 4860 sqlite3 *db, /* Database to be rekeyed */ 4861 const void *pKey, int nKey /* The new key */ 4862); 4863SQLITE_API int SQLITE_STDCALL sqlite3_rekey_v2( 4864 sqlite3 *db, /* Database to be rekeyed */ 4865 const char *zDbName, /* Name of the database */ 4866 const void *pKey, int nKey /* The new key */ 4867); 4868 4869/* 4870** Specify the activation key for a SEE database. Unless 4871** activated, none of the SEE routines will work. 4872*/ 4873SQLITE_API void SQLITE_STDCALL sqlite3_activate_see( 4874 const char *zPassPhrase /* Activation phrase */ 4875); 4876#endif 4877 4878#ifdef SQLITE_ENABLE_CEROD 4879/* 4880** Specify the activation key for a CEROD database. Unless 4881** activated, none of the CEROD routines will work. 4882*/ 4883SQLITE_API void SQLITE_STDCALL sqlite3_activate_cerod( 4884 const char *zPassPhrase /* Activation phrase */ 4885); 4886#endif 4887 4888/* 4889** CAPI3REF: Suspend Execution For A Short Time 4890** 4891** The sqlite3_sleep() function causes the current thread to suspend execution 4892** for at least a number of milliseconds specified in its parameter. 4893** 4894** If the operating system does not support sleep requests with 4895** millisecond time resolution, then the time will be rounded up to 4896** the nearest second. The number of milliseconds of sleep actually 4897** requested from the operating system is returned. 4898** 4899** ^SQLite implements this interface by calling the xSleep() 4900** method of the default [sqlite3_vfs] object. If the xSleep() method 4901** of the default VFS is not implemented correctly, or not implemented at 4902** all, then the behavior of sqlite3_sleep() may deviate from the description 4903** in the previous paragraphs. 4904*/ 4905SQLITE_API int SQLITE_STDCALL sqlite3_sleep(int); 4906 4907/* 4908** CAPI3REF: Name Of The Folder Holding Temporary Files 4909** 4910** ^(If this global variable is made to point to a string which is 4911** the name of a folder (a.k.a. directory), then all temporary files 4912** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4913** will be placed in that directory.)^ ^If this variable 4914** is a NULL pointer, then SQLite performs a search for an appropriate 4915** temporary file directory. 4916** 4917** Applications are strongly discouraged from using this global variable. 4918** It is required to set a temporary folder on Windows Runtime (WinRT). 4919** But for all other platforms, it is highly recommended that applications 4920** neither read nor write this variable. This global variable is a relic 4921** that exists for backwards compatibility of legacy applications and should 4922** be avoided in new projects. 4923** 4924** It is not safe to read or modify this variable in more than one 4925** thread at a time. It is not safe to read or modify this variable 4926** if a [database connection] is being used at the same time in a separate 4927** thread. 4928** It is intended that this variable be set once 4929** as part of process initialization and before any SQLite interface 4930** routines have been called and that this variable remain unchanged 4931** thereafter. 4932** 4933** ^The [temp_store_directory pragma] may modify this variable and cause 4934** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4935** the [temp_store_directory pragma] always assumes that any string 4936** that this variable points to is held in memory obtained from 4937** [sqlite3_malloc] and the pragma may attempt to free that memory 4938** using [sqlite3_free]. 4939** Hence, if this variable is modified directly, either it should be 4940** made NULL or made to point to memory obtained from [sqlite3_malloc] 4941** or else the use of the [temp_store_directory pragma] should be avoided. 4942** Except when requested by the [temp_store_directory pragma], SQLite 4943** does not free the memory that sqlite3_temp_directory points to. If 4944** the application wants that memory to be freed, it must do 4945** so itself, taking care to only do so after all [database connection] 4946** objects have been destroyed. 4947** 4948** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4949** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4950** features that require the use of temporary files may fail. Here is an 4951** example of how to do this using C++ with the Windows Runtime: 4952** 4953** <blockquote><pre> 4954** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4955** TemporaryFolder->Path->Data(); 4956** char zPathBuf[MAX_PATH + 1]; 4957** memset(zPathBuf, 0, sizeof(zPathBuf)); 4958** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4959** NULL, NULL); 4960** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4961** </pre></blockquote> 4962*/ 4963SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 4964 4965/* 4966** CAPI3REF: Name Of The Folder Holding Database Files 4967** 4968** ^(If this global variable is made to point to a string which is 4969** the name of a folder (a.k.a. directory), then all database files 4970** specified with a relative pathname and created or accessed by 4971** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4972** to be relative to that directory.)^ ^If this variable is a NULL 4973** pointer, then SQLite assumes that all database files specified 4974** with a relative pathname are relative to the current directory 4975** for the process. Only the windows VFS makes use of this global 4976** variable; it is ignored by the unix VFS. 4977** 4978** Changing the value of this variable while a database connection is 4979** open can result in a corrupt database. 4980** 4981** It is not safe to read or modify this variable in more than one 4982** thread at a time. It is not safe to read or modify this variable 4983** if a [database connection] is being used at the same time in a separate 4984** thread. 4985** It is intended that this variable be set once 4986** as part of process initialization and before any SQLite interface 4987** routines have been called and that this variable remain unchanged 4988** thereafter. 4989** 4990** ^The [data_store_directory pragma] may modify this variable and cause 4991** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4992** the [data_store_directory pragma] always assumes that any string 4993** that this variable points to is held in memory obtained from 4994** [sqlite3_malloc] and the pragma may attempt to free that memory 4995** using [sqlite3_free]. 4996** Hence, if this variable is modified directly, either it should be 4997** made NULL or made to point to memory obtained from [sqlite3_malloc] 4998** or else the use of the [data_store_directory pragma] should be avoided. 4999*/ 5000SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory; 5001 5002/* 5003** CAPI3REF: Test For Auto-Commit Mode 5004** KEYWORDS: {autocommit mode} 5005** METHOD: sqlite3 5006** 5007** ^The sqlite3_get_autocommit() interface returns non-zero or 5008** zero if the given database connection is or is not in autocommit mode, 5009** respectively. ^Autocommit mode is on by default. 5010** ^Autocommit mode is disabled by a [BEGIN] statement. 5011** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5012** 5013** If certain kinds of errors occur on a statement within a multi-statement 5014** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5015** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5016** transaction might be rolled back automatically. The only way to 5017** find out whether SQLite automatically rolled back the transaction after 5018** an error is to use this function. 5019** 5020** If another thread changes the autocommit status of the database 5021** connection while this routine is running, then the return value 5022** is undefined. 5023*/ 5024SQLITE_API int SQLITE_STDCALL sqlite3_get_autocommit(sqlite3*); 5025 5026/* 5027** CAPI3REF: Find The Database Handle Of A Prepared Statement 5028** METHOD: sqlite3_stmt 5029** 5030** ^The sqlite3_db_handle interface returns the [database connection] handle 5031** to which a [prepared statement] belongs. ^The [database connection] 5032** returned by sqlite3_db_handle is the same [database connection] 5033** that was the first argument 5034** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5035** create the statement in the first place. 5036*/ 5037SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_db_handle(sqlite3_stmt*); 5038 5039/* 5040** CAPI3REF: Return The Filename For A Database Connection 5041** METHOD: sqlite3 5042** 5043** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5044** associated with database N of connection D. ^The main database file 5045** has the name "main". If there is no attached database N on the database 5046** connection D, or if database N is a temporary or in-memory database, then 5047** a NULL pointer is returned. 5048** 5049** ^The filename returned by this function is the output of the 5050** xFullPathname method of the [VFS]. ^In other words, the filename 5051** will be an absolute pathname, even if the filename used 5052** to open the database originally was a URI or relative pathname. 5053*/ 5054SQLITE_API const char *SQLITE_STDCALL sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5055 5056/* 5057** CAPI3REF: Determine if a database is read-only 5058** METHOD: sqlite3 5059** 5060** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5061** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5062** the name of a database on connection D. 5063*/ 5064SQLITE_API int SQLITE_STDCALL sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5065 5066/* 5067** CAPI3REF: Find the next prepared statement 5068** METHOD: sqlite3 5069** 5070** ^This interface returns a pointer to the next [prepared statement] after 5071** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5072** then this interface returns a pointer to the first prepared statement 5073** associated with the database connection pDb. ^If no prepared statement 5074** satisfies the conditions of this routine, it returns NULL. 5075** 5076** The [database connection] pointer D in a call to 5077** [sqlite3_next_stmt(D,S)] must refer to an open database 5078** connection and in particular must not be a NULL pointer. 5079*/ 5080SQLITE_API sqlite3_stmt *SQLITE_STDCALL sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5081 5082/* 5083** CAPI3REF: Commit And Rollback Notification Callbacks 5084** METHOD: sqlite3 5085** 5086** ^The sqlite3_commit_hook() interface registers a callback 5087** function to be invoked whenever a transaction is [COMMIT | committed]. 5088** ^Any callback set by a previous call to sqlite3_commit_hook() 5089** for the same database connection is overridden. 5090** ^The sqlite3_rollback_hook() interface registers a callback 5091** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5092** ^Any callback set by a previous call to sqlite3_rollback_hook() 5093** for the same database connection is overridden. 5094** ^The pArg argument is passed through to the callback. 5095** ^If the callback on a commit hook function returns non-zero, 5096** then the commit is converted into a rollback. 5097** 5098** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5099** return the P argument from the previous call of the same function 5100** on the same [database connection] D, or NULL for 5101** the first call for each function on D. 5102** 5103** The commit and rollback hook callbacks are not reentrant. 5104** The callback implementation must not do anything that will modify 5105** the database connection that invoked the callback. Any actions 5106** to modify the database connection must be deferred until after the 5107** completion of the [sqlite3_step()] call that triggered the commit 5108** or rollback hook in the first place. 5109** Note that running any other SQL statements, including SELECT statements, 5110** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5111** the database connections for the meaning of "modify" in this paragraph. 5112** 5113** ^Registering a NULL function disables the callback. 5114** 5115** ^When the commit hook callback routine returns zero, the [COMMIT] 5116** operation is allowed to continue normally. ^If the commit hook 5117** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5118** ^The rollback hook is invoked on a rollback that results from a commit 5119** hook returning non-zero, just as it would be with any other rollback. 5120** 5121** ^For the purposes of this API, a transaction is said to have been 5122** rolled back if an explicit "ROLLBACK" statement is executed, or 5123** an error or constraint causes an implicit rollback to occur. 5124** ^The rollback callback is not invoked if a transaction is 5125** automatically rolled back because the database connection is closed. 5126** 5127** See also the [sqlite3_update_hook()] interface. 5128*/ 5129SQLITE_API void *SQLITE_STDCALL sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5130SQLITE_API void *SQLITE_STDCALL sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5131 5132/* 5133** CAPI3REF: Data Change Notification Callbacks 5134** METHOD: sqlite3 5135** 5136** ^The sqlite3_update_hook() interface registers a callback function 5137** with the [database connection] identified by the first argument 5138** to be invoked whenever a row is updated, inserted or deleted in 5139** a rowid table. 5140** ^Any callback set by a previous call to this function 5141** for the same database connection is overridden. 5142** 5143** ^The second argument is a pointer to the function to invoke when a 5144** row is updated, inserted or deleted in a rowid table. 5145** ^The first argument to the callback is a copy of the third argument 5146** to sqlite3_update_hook(). 5147** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5148** or [SQLITE_UPDATE], depending on the operation that caused the callback 5149** to be invoked. 5150** ^The third and fourth arguments to the callback contain pointers to the 5151** database and table name containing the affected row. 5152** ^The final callback parameter is the [rowid] of the row. 5153** ^In the case of an update, this is the [rowid] after the update takes place. 5154** 5155** ^(The update hook is not invoked when internal system tables are 5156** modified (i.e. sqlite_master and sqlite_sequence).)^ 5157** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5158** 5159** ^In the current implementation, the update hook 5160** is not invoked when duplication rows are deleted because of an 5161** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5162** invoked when rows are deleted using the [truncate optimization]. 5163** The exceptions defined in this paragraph might change in a future 5164** release of SQLite. 5165** 5166** The update hook implementation must not do anything that will modify 5167** the database connection that invoked the update hook. Any actions 5168** to modify the database connection must be deferred until after the 5169** completion of the [sqlite3_step()] call that triggered the update hook. 5170** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5171** database connections for the meaning of "modify" in this paragraph. 5172** 5173** ^The sqlite3_update_hook(D,C,P) function 5174** returns the P argument from the previous call 5175** on the same [database connection] D, or NULL for 5176** the first call on D. 5177** 5178** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 5179** interfaces. 5180*/ 5181SQLITE_API void *SQLITE_STDCALL sqlite3_update_hook( 5182 sqlite3*, 5183 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5184 void* 5185); 5186 5187/* 5188** CAPI3REF: Enable Or Disable Shared Pager Cache 5189** 5190** ^(This routine enables or disables the sharing of the database cache 5191** and schema data structures between [database connection | connections] 5192** to the same database. Sharing is enabled if the argument is true 5193** and disabled if the argument is false.)^ 5194** 5195** ^Cache sharing is enabled and disabled for an entire process. 5196** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 5197** sharing was enabled or disabled for each thread separately. 5198** 5199** ^(The cache sharing mode set by this interface effects all subsequent 5200** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5201** Existing database connections continue use the sharing mode 5202** that was in effect at the time they were opened.)^ 5203** 5204** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5205** successfully. An [error code] is returned otherwise.)^ 5206** 5207** ^Shared cache is disabled by default. But this might change in 5208** future releases of SQLite. Applications that care about shared 5209** cache setting should set it explicitly. 5210** 5211** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5212** and will always return SQLITE_MISUSE. On those systems, 5213** shared cache mode should be enabled per-database connection via 5214** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5215** 5216** This interface is threadsafe on processors where writing a 5217** 32-bit integer is atomic. 5218** 5219** See Also: [SQLite Shared-Cache Mode] 5220*/ 5221SQLITE_API int SQLITE_STDCALL sqlite3_enable_shared_cache(int); 5222 5223/* 5224** CAPI3REF: Attempt To Free Heap Memory 5225** 5226** ^The sqlite3_release_memory() interface attempts to free N bytes 5227** of heap memory by deallocating non-essential memory allocations 5228** held by the database library. Memory used to cache database 5229** pages to improve performance is an example of non-essential memory. 5230** ^sqlite3_release_memory() returns the number of bytes actually freed, 5231** which might be more or less than the amount requested. 5232** ^The sqlite3_release_memory() routine is a no-op returning zero 5233** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5234** 5235** See also: [sqlite3_db_release_memory()] 5236*/ 5237SQLITE_API int SQLITE_STDCALL sqlite3_release_memory(int); 5238 5239/* 5240** CAPI3REF: Free Memory Used By A Database Connection 5241** METHOD: sqlite3 5242** 5243** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5244** memory as possible from database connection D. Unlike the 5245** [sqlite3_release_memory()] interface, this interface is in effect even 5246** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5247** omitted. 5248** 5249** See also: [sqlite3_release_memory()] 5250*/ 5251SQLITE_API int SQLITE_STDCALL sqlite3_db_release_memory(sqlite3*); 5252 5253/* 5254** CAPI3REF: Impose A Limit On Heap Size 5255** 5256** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5257** soft limit on the amount of heap memory that may be allocated by SQLite. 5258** ^SQLite strives to keep heap memory utilization below the soft heap 5259** limit by reducing the number of pages held in the page cache 5260** as heap memory usages approaches the limit. 5261** ^The soft heap limit is "soft" because even though SQLite strives to stay 5262** below the limit, it will exceed the limit rather than generate 5263** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5264** is advisory only. 5265** 5266** ^The return value from sqlite3_soft_heap_limit64() is the size of 5267** the soft heap limit prior to the call, or negative in the case of an 5268** error. ^If the argument N is negative 5269** then no change is made to the soft heap limit. Hence, the current 5270** size of the soft heap limit can be determined by invoking 5271** sqlite3_soft_heap_limit64() with a negative argument. 5272** 5273** ^If the argument N is zero then the soft heap limit is disabled. 5274** 5275** ^(The soft heap limit is not enforced in the current implementation 5276** if one or more of following conditions are true: 5277** 5278** <ul> 5279** <li> The soft heap limit is set to zero. 5280** <li> Memory accounting is disabled using a combination of the 5281** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5282** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5283** <li> An alternative page cache implementation is specified using 5284** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5285** <li> The page cache allocates from its own memory pool supplied 5286** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5287** from the heap. 5288** </ul>)^ 5289** 5290** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 5291** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5292** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5293** the soft heap limit is enforced on every memory allocation. Without 5294** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5295** when memory is allocated by the page cache. Testing suggests that because 5296** the page cache is the predominate memory user in SQLite, most 5297** applications will achieve adequate soft heap limit enforcement without 5298** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5299** 5300** The circumstances under which SQLite will enforce the soft heap limit may 5301** changes in future releases of SQLite. 5302*/ 5303SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_soft_heap_limit64(sqlite3_int64 N); 5304 5305/* 5306** CAPI3REF: Deprecated Soft Heap Limit Interface 5307** DEPRECATED 5308** 5309** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5310** interface. This routine is provided for historical compatibility 5311** only. All new applications should use the 5312** [sqlite3_soft_heap_limit64()] interface rather than this one. 5313*/ 5314SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_soft_heap_limit(int N); 5315 5316 5317/* 5318** CAPI3REF: Extract Metadata About A Column Of A Table 5319** METHOD: sqlite3 5320** 5321** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5322** information about column C of table T in database D 5323** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5324** interface returns SQLITE_OK and fills in the non-NULL pointers in 5325** the final five arguments with appropriate values if the specified 5326** column exists. ^The sqlite3_table_column_metadata() interface returns 5327** SQLITE_ERROR and if the specified column does not exist. 5328** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5329** NULL pointer, then this routine simply checks for the existance of the 5330** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5331** does not. 5332** 5333** ^The column is identified by the second, third and fourth parameters to 5334** this function. ^(The second parameter is either the name of the database 5335** (i.e. "main", "temp", or an attached database) containing the specified 5336** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5337** for the table using the same algorithm used by the database engine to 5338** resolve unqualified table references. 5339** 5340** ^The third and fourth parameters to this function are the table and column 5341** name of the desired column, respectively. 5342** 5343** ^Metadata is returned by writing to the memory locations passed as the 5th 5344** and subsequent parameters to this function. ^Any of these arguments may be 5345** NULL, in which case the corresponding element of metadata is omitted. 5346** 5347** ^(<blockquote> 5348** <table border="1"> 5349** <tr><th> Parameter <th> Output<br>Type <th> Description 5350** 5351** <tr><td> 5th <td> const char* <td> Data type 5352** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5353** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5354** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5355** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5356** </table> 5357** </blockquote>)^ 5358** 5359** ^The memory pointed to by the character pointers returned for the 5360** declaration type and collation sequence is valid until the next 5361** call to any SQLite API function. 5362** 5363** ^If the specified table is actually a view, an [error code] is returned. 5364** 5365** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5366** is not a [WITHOUT ROWID] table and an 5367** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5368** parameters are set for the explicitly declared column. ^(If there is no 5369** [INTEGER PRIMARY KEY] column, then the outputs 5370** for the [rowid] are set as follows: 5371** 5372** <pre> 5373** data type: "INTEGER" 5374** collation sequence: "BINARY" 5375** not null: 0 5376** primary key: 1 5377** auto increment: 0 5378** </pre>)^ 5379** 5380** ^This function causes all database schemas to be read from disk and 5381** parsed, if that has not already been done, and returns an error if 5382** any errors are encountered while loading the schema. 5383*/ 5384SQLITE_API int SQLITE_STDCALL sqlite3_table_column_metadata( 5385 sqlite3 *db, /* Connection handle */ 5386 const char *zDbName, /* Database name or NULL */ 5387 const char *zTableName, /* Table name */ 5388 const char *zColumnName, /* Column name */ 5389 char const **pzDataType, /* OUTPUT: Declared data type */ 5390 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5391 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5392 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5393 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5394); 5395 5396/* 5397** CAPI3REF: Load An Extension 5398** METHOD: sqlite3 5399** 5400** ^This interface loads an SQLite extension library from the named file. 5401** 5402** ^The sqlite3_load_extension() interface attempts to load an 5403** [SQLite extension] library contained in the file zFile. If 5404** the file cannot be loaded directly, attempts are made to load 5405** with various operating-system specific extensions added. 5406** So for example, if "samplelib" cannot be loaded, then names like 5407** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5408** be tried also. 5409** 5410** ^The entry point is zProc. 5411** ^(zProc may be 0, in which case SQLite will try to come up with an 5412** entry point name on its own. It first tries "sqlite3_extension_init". 5413** If that does not work, it constructs a name "sqlite3_X_init" where the 5414** X is consists of the lower-case equivalent of all ASCII alphabetic 5415** characters in the filename from the last "/" to the first following 5416** "." and omitting any initial "lib".)^ 5417** ^The sqlite3_load_extension() interface returns 5418** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5419** ^If an error occurs and pzErrMsg is not 0, then the 5420** [sqlite3_load_extension()] interface shall attempt to 5421** fill *pzErrMsg with error message text stored in memory 5422** obtained from [sqlite3_malloc()]. The calling function 5423** should free this memory by calling [sqlite3_free()]. 5424** 5425** ^Extension loading must be enabled using 5426** [sqlite3_enable_load_extension()] prior to calling this API, 5427** otherwise an error will be returned. 5428** 5429** See also the [load_extension() SQL function]. 5430*/ 5431SQLITE_API int SQLITE_STDCALL sqlite3_load_extension( 5432 sqlite3 *db, /* Load the extension into this database connection */ 5433 const char *zFile, /* Name of the shared library containing extension */ 5434 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5435 char **pzErrMsg /* Put error message here if not 0 */ 5436); 5437 5438/* 5439** CAPI3REF: Enable Or Disable Extension Loading 5440** METHOD: sqlite3 5441** 5442** ^So as not to open security holes in older applications that are 5443** unprepared to deal with [extension loading], and as a means of disabling 5444** [extension loading] while evaluating user-entered SQL, the following API 5445** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5446** 5447** ^Extension loading is off by default. 5448** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5449** to turn extension loading on and call it with onoff==0 to turn 5450** it back off again. 5451*/ 5452SQLITE_API int SQLITE_STDCALL sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5453 5454/* 5455** CAPI3REF: Automatically Load Statically Linked Extensions 5456** 5457** ^This interface causes the xEntryPoint() function to be invoked for 5458** each new [database connection] that is created. The idea here is that 5459** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5460** that is to be automatically loaded into all new database connections. 5461** 5462** ^(Even though the function prototype shows that xEntryPoint() takes 5463** no arguments and returns void, SQLite invokes xEntryPoint() with three 5464** arguments and expects and integer result as if the signature of the 5465** entry point where as follows: 5466** 5467** <blockquote><pre> 5468** int xEntryPoint( 5469** sqlite3 *db, 5470** const char **pzErrMsg, 5471** const struct sqlite3_api_routines *pThunk 5472** ); 5473** </pre></blockquote>)^ 5474** 5475** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5476** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5477** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5478** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5479** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5480** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5481** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5482** 5483** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5484** on the list of automatic extensions is a harmless no-op. ^No entry point 5485** will be called more than once for each database connection that is opened. 5486** 5487** See also: [sqlite3_reset_auto_extension()] 5488** and [sqlite3_cancel_auto_extension()] 5489*/ 5490SQLITE_API int SQLITE_STDCALL sqlite3_auto_extension(void (*xEntryPoint)(void)); 5491 5492/* 5493** CAPI3REF: Cancel Automatic Extension Loading 5494** 5495** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5496** initialization routine X that was registered using a prior call to 5497** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5498** routine returns 1 if initialization routine X was successfully 5499** unregistered and it returns 0 if X was not on the list of initialization 5500** routines. 5501*/ 5502SQLITE_API int SQLITE_STDCALL sqlite3_cancel_auto_extension(void (*xEntryPoint)(void)); 5503 5504/* 5505** CAPI3REF: Reset Automatic Extension Loading 5506** 5507** ^This interface disables all automatic extensions previously 5508** registered using [sqlite3_auto_extension()]. 5509*/ 5510SQLITE_API void SQLITE_STDCALL sqlite3_reset_auto_extension(void); 5511 5512/* 5513** The interface to the virtual-table mechanism is currently considered 5514** to be experimental. The interface might change in incompatible ways. 5515** If this is a problem for you, do not use the interface at this time. 5516** 5517** When the virtual-table mechanism stabilizes, we will declare the 5518** interface fixed, support it indefinitely, and remove this comment. 5519*/ 5520 5521/* 5522** Structures used by the virtual table interface 5523*/ 5524typedef struct sqlite3_vtab sqlite3_vtab; 5525typedef struct sqlite3_index_info sqlite3_index_info; 5526typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5527typedef struct sqlite3_module sqlite3_module; 5528 5529/* 5530** CAPI3REF: Virtual Table Object 5531** KEYWORDS: sqlite3_module {virtual table module} 5532** 5533** This structure, sometimes called a "virtual table module", 5534** defines the implementation of a [virtual tables]. 5535** This structure consists mostly of methods for the module. 5536** 5537** ^A virtual table module is created by filling in a persistent 5538** instance of this structure and passing a pointer to that instance 5539** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5540** ^The registration remains valid until it is replaced by a different 5541** module or until the [database connection] closes. The content 5542** of this structure must not change while it is registered with 5543** any database connection. 5544*/ 5545struct sqlite3_module { 5546 int iVersion; 5547 int (*xCreate)(sqlite3*, void *pAux, 5548 int argc, const char *const*argv, 5549 sqlite3_vtab **ppVTab, char**); 5550 int (*xConnect)(sqlite3*, void *pAux, 5551 int argc, const char *const*argv, 5552 sqlite3_vtab **ppVTab, char**); 5553 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5554 int (*xDisconnect)(sqlite3_vtab *pVTab); 5555 int (*xDestroy)(sqlite3_vtab *pVTab); 5556 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5557 int (*xClose)(sqlite3_vtab_cursor*); 5558 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5559 int argc, sqlite3_value **argv); 5560 int (*xNext)(sqlite3_vtab_cursor*); 5561 int (*xEof)(sqlite3_vtab_cursor*); 5562 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5563 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5564 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5565 int (*xBegin)(sqlite3_vtab *pVTab); 5566 int (*xSync)(sqlite3_vtab *pVTab); 5567 int (*xCommit)(sqlite3_vtab *pVTab); 5568 int (*xRollback)(sqlite3_vtab *pVTab); 5569 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5570 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5571 void **ppArg); 5572 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5573 /* The methods above are in version 1 of the sqlite_module object. Those 5574 ** below are for version 2 and greater. */ 5575 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5576 int (*xRelease)(sqlite3_vtab *pVTab, int); 5577 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5578}; 5579 5580/* 5581** CAPI3REF: Virtual Table Indexing Information 5582** KEYWORDS: sqlite3_index_info 5583** 5584** The sqlite3_index_info structure and its substructures is used as part 5585** of the [virtual table] interface to 5586** pass information into and receive the reply from the [xBestIndex] 5587** method of a [virtual table module]. The fields under **Inputs** are the 5588** inputs to xBestIndex and are read-only. xBestIndex inserts its 5589** results into the **Outputs** fields. 5590** 5591** ^(The aConstraint[] array records WHERE clause constraints of the form: 5592** 5593** <blockquote>column OP expr</blockquote> 5594** 5595** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5596** stored in aConstraint[].op using one of the 5597** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5598** ^(The index of the column is stored in 5599** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5600** expr on the right-hand side can be evaluated (and thus the constraint 5601** is usable) and false if it cannot.)^ 5602** 5603** ^The optimizer automatically inverts terms of the form "expr OP column" 5604** and makes other simplifications to the WHERE clause in an attempt to 5605** get as many WHERE clause terms into the form shown above as possible. 5606** ^The aConstraint[] array only reports WHERE clause terms that are 5607** relevant to the particular virtual table being queried. 5608** 5609** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5610** ^Each term of aOrderBy records a column of the ORDER BY clause. 5611** 5612** The [xBestIndex] method must fill aConstraintUsage[] with information 5613** about what parameters to pass to xFilter. ^If argvIndex>0 then 5614** the right-hand side of the corresponding aConstraint[] is evaluated 5615** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5616** is true, then the constraint is assumed to be fully handled by the 5617** virtual table and is not checked again by SQLite.)^ 5618** 5619** ^The idxNum and idxPtr values are recorded and passed into the 5620** [xFilter] method. 5621** ^[sqlite3_free()] is used to free idxPtr if and only if 5622** needToFreeIdxPtr is true. 5623** 5624** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5625** the correct order to satisfy the ORDER BY clause so that no separate 5626** sorting step is required. 5627** 5628** ^The estimatedCost value is an estimate of the cost of a particular 5629** strategy. A cost of N indicates that the cost of the strategy is similar 5630** to a linear scan of an SQLite table with N rows. A cost of log(N) 5631** indicates that the expense of the operation is similar to that of a 5632** binary search on a unique indexed field of an SQLite table with N rows. 5633** 5634** ^The estimatedRows value is an estimate of the number of rows that 5635** will be returned by the strategy. 5636** 5637** The xBestIndex method may optionally populate the idxFlags field with a 5638** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 5639** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 5640** assumes that the strategy may visit at most one row. 5641** 5642** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 5643** SQLite also assumes that if a call to the xUpdate() method is made as 5644** part of the same statement to delete or update a virtual table row and the 5645** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 5646** any database changes. In other words, if the xUpdate() returns 5647** SQLITE_CONSTRAINT, the database contents must be exactly as they were 5648** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 5649** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 5650** the xUpdate method are automatically rolled back by SQLite. 5651** 5652** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 5653** structure for SQLite version 3.8.2. If a virtual table extension is 5654** used with an SQLite version earlier than 3.8.2, the results of attempting 5655** to read or write the estimatedRows field are undefined (but are likely 5656** to included crashing the application). The estimatedRows field should 5657** therefore only be used if [sqlite3_libversion_number()] returns a 5658** value greater than or equal to 3008002. Similarly, the idxFlags field 5659** was added for version 3.9.0. It may therefore only be used if 5660** sqlite3_libversion_number() returns a value greater than or equal to 5661** 3009000. 5662*/ 5663struct sqlite3_index_info { 5664 /* Inputs */ 5665 int nConstraint; /* Number of entries in aConstraint */ 5666 struct sqlite3_index_constraint { 5667 int iColumn; /* Column on left-hand side of constraint */ 5668 unsigned char op; /* Constraint operator */ 5669 unsigned char usable; /* True if this constraint is usable */ 5670 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5671 } *aConstraint; /* Table of WHERE clause constraints */ 5672 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5673 struct sqlite3_index_orderby { 5674 int iColumn; /* Column number */ 5675 unsigned char desc; /* True for DESC. False for ASC. */ 5676 } *aOrderBy; /* The ORDER BY clause */ 5677 /* Outputs */ 5678 struct sqlite3_index_constraint_usage { 5679 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5680 unsigned char omit; /* Do not code a test for this constraint */ 5681 } *aConstraintUsage; 5682 int idxNum; /* Number used to identify the index */ 5683 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5684 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5685 int orderByConsumed; /* True if output is already ordered */ 5686 double estimatedCost; /* Estimated cost of using this index */ 5687 /* Fields below are only available in SQLite 3.8.2 and later */ 5688 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 5689 /* Fields below are only available in SQLite 3.9.0 and later */ 5690 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 5691}; 5692 5693/* 5694** CAPI3REF: Virtual Table Scan Flags 5695*/ 5696#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 5697 5698/* 5699** CAPI3REF: Virtual Table Constraint Operator Codes 5700** 5701** These macros defined the allowed values for the 5702** [sqlite3_index_info].aConstraint[].op field. Each value represents 5703** an operator that is part of a constraint term in the wHERE clause of 5704** a query that uses a [virtual table]. 5705*/ 5706#define SQLITE_INDEX_CONSTRAINT_EQ 2 5707#define SQLITE_INDEX_CONSTRAINT_GT 4 5708#define SQLITE_INDEX_CONSTRAINT_LE 8 5709#define SQLITE_INDEX_CONSTRAINT_LT 16 5710#define SQLITE_INDEX_CONSTRAINT_GE 32 5711#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5712 5713/* 5714** CAPI3REF: Register A Virtual Table Implementation 5715** METHOD: sqlite3 5716** 5717** ^These routines are used to register a new [virtual table module] name. 5718** ^Module names must be registered before 5719** creating a new [virtual table] using the module and before using a 5720** preexisting [virtual table] for the module. 5721** 5722** ^The module name is registered on the [database connection] specified 5723** by the first parameter. ^The name of the module is given by the 5724** second parameter. ^The third parameter is a pointer to 5725** the implementation of the [virtual table module]. ^The fourth 5726** parameter is an arbitrary client data pointer that is passed through 5727** into the [xCreate] and [xConnect] methods of the virtual table module 5728** when a new virtual table is be being created or reinitialized. 5729** 5730** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5731** is a pointer to a destructor for the pClientData. ^SQLite will 5732** invoke the destructor function (if it is not NULL) when SQLite 5733** no longer needs the pClientData pointer. ^The destructor will also 5734** be invoked if the call to sqlite3_create_module_v2() fails. 5735** ^The sqlite3_create_module() 5736** interface is equivalent to sqlite3_create_module_v2() with a NULL 5737** destructor. 5738*/ 5739SQLITE_API int SQLITE_STDCALL sqlite3_create_module( 5740 sqlite3 *db, /* SQLite connection to register module with */ 5741 const char *zName, /* Name of the module */ 5742 const sqlite3_module *p, /* Methods for the module */ 5743 void *pClientData /* Client data for xCreate/xConnect */ 5744); 5745SQLITE_API int SQLITE_STDCALL sqlite3_create_module_v2( 5746 sqlite3 *db, /* SQLite connection to register module with */ 5747 const char *zName, /* Name of the module */ 5748 const sqlite3_module *p, /* Methods for the module */ 5749 void *pClientData, /* Client data for xCreate/xConnect */ 5750 void(*xDestroy)(void*) /* Module destructor function */ 5751); 5752 5753/* 5754** CAPI3REF: Virtual Table Instance Object 5755** KEYWORDS: sqlite3_vtab 5756** 5757** Every [virtual table module] implementation uses a subclass 5758** of this object to describe a particular instance 5759** of the [virtual table]. Each subclass will 5760** be tailored to the specific needs of the module implementation. 5761** The purpose of this superclass is to define certain fields that are 5762** common to all module implementations. 5763** 5764** ^Virtual tables methods can set an error message by assigning a 5765** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5766** take care that any prior string is freed by a call to [sqlite3_free()] 5767** prior to assigning a new string to zErrMsg. ^After the error message 5768** is delivered up to the client application, the string will be automatically 5769** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5770*/ 5771struct sqlite3_vtab { 5772 const sqlite3_module *pModule; /* The module for this virtual table */ 5773 int nRef; /* Number of open cursors */ 5774 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5775 /* Virtual table implementations will typically add additional fields */ 5776}; 5777 5778/* 5779** CAPI3REF: Virtual Table Cursor Object 5780** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5781** 5782** Every [virtual table module] implementation uses a subclass of the 5783** following structure to describe cursors that point into the 5784** [virtual table] and are used 5785** to loop through the virtual table. Cursors are created using the 5786** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5787** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5788** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5789** of the module. Each module implementation will define 5790** the content of a cursor structure to suit its own needs. 5791** 5792** This superclass exists in order to define fields of the cursor that 5793** are common to all implementations. 5794*/ 5795struct sqlite3_vtab_cursor { 5796 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5797 /* Virtual table implementations will typically add additional fields */ 5798}; 5799 5800/* 5801** CAPI3REF: Declare The Schema Of A Virtual Table 5802** 5803** ^The [xCreate] and [xConnect] methods of a 5804** [virtual table module] call this interface 5805** to declare the format (the names and datatypes of the columns) of 5806** the virtual tables they implement. 5807*/ 5808SQLITE_API int SQLITE_STDCALL sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5809 5810/* 5811** CAPI3REF: Overload A Function For A Virtual Table 5812** METHOD: sqlite3 5813** 5814** ^(Virtual tables can provide alternative implementations of functions 5815** using the [xFindFunction] method of the [virtual table module]. 5816** But global versions of those functions 5817** must exist in order to be overloaded.)^ 5818** 5819** ^(This API makes sure a global version of a function with a particular 5820** name and number of parameters exists. If no such function exists 5821** before this API is called, a new function is created.)^ ^The implementation 5822** of the new function always causes an exception to be thrown. So 5823** the new function is not good for anything by itself. Its only 5824** purpose is to be a placeholder function that can be overloaded 5825** by a [virtual table]. 5826*/ 5827SQLITE_API int SQLITE_STDCALL sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5828 5829/* 5830** The interface to the virtual-table mechanism defined above (back up 5831** to a comment remarkably similar to this one) is currently considered 5832** to be experimental. The interface might change in incompatible ways. 5833** If this is a problem for you, do not use the interface at this time. 5834** 5835** When the virtual-table mechanism stabilizes, we will declare the 5836** interface fixed, support it indefinitely, and remove this comment. 5837*/ 5838 5839/* 5840** CAPI3REF: A Handle To An Open BLOB 5841** KEYWORDS: {BLOB handle} {BLOB handles} 5842** 5843** An instance of this object represents an open BLOB on which 5844** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5845** ^Objects of this type are created by [sqlite3_blob_open()] 5846** and destroyed by [sqlite3_blob_close()]. 5847** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5848** can be used to read or write small subsections of the BLOB. 5849** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5850*/ 5851typedef struct sqlite3_blob sqlite3_blob; 5852 5853/* 5854** CAPI3REF: Open A BLOB For Incremental I/O 5855** METHOD: sqlite3 5856** CONSTRUCTOR: sqlite3_blob 5857** 5858** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5859** in row iRow, column zColumn, table zTable in database zDb; 5860** in other words, the same BLOB that would be selected by: 5861** 5862** <pre> 5863** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5864** </pre>)^ 5865** 5866** ^(Parameter zDb is not the filename that contains the database, but 5867** rather the symbolic name of the database. For attached databases, this is 5868** the name that appears after the AS keyword in the [ATTACH] statement. 5869** For the main database file, the database name is "main". For TEMP 5870** tables, the database name is "temp".)^ 5871** 5872** ^If the flags parameter is non-zero, then the BLOB is opened for read 5873** and write access. ^If the flags parameter is zero, the BLOB is opened for 5874** read-only access. 5875** 5876** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 5877** in *ppBlob. Otherwise an [error code] is returned and, unless the error 5878** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 5879** the API is not misused, it is always safe to call [sqlite3_blob_close()] 5880** on *ppBlob after this function it returns. 5881** 5882** This function fails with SQLITE_ERROR if any of the following are true: 5883** <ul> 5884** <li> ^(Database zDb does not exist)^, 5885** <li> ^(Table zTable does not exist within database zDb)^, 5886** <li> ^(Table zTable is a WITHOUT ROWID table)^, 5887** <li> ^(Column zColumn does not exist)^, 5888** <li> ^(Row iRow is not present in the table)^, 5889** <li> ^(The specified column of row iRow contains a value that is not 5890** a TEXT or BLOB value)^, 5891** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 5892** constraint and the blob is being opened for read/write access)^, 5893** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 5894** column zColumn is part of a [child key] definition and the blob is 5895** being opened for read/write access)^. 5896** </ul> 5897** 5898** ^Unless it returns SQLITE_MISUSE, this function sets the 5899** [database connection] error code and message accessible via 5900** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 5901** 5902** 5903** ^(If the row that a BLOB handle points to is modified by an 5904** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5905** then the BLOB handle is marked as "expired". 5906** This is true if any column of the row is changed, even a column 5907** other than the one the BLOB handle is open on.)^ 5908** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5909** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5910** ^(Changes written into a BLOB prior to the BLOB expiring are not 5911** rolled back by the expiration of the BLOB. Such changes will eventually 5912** commit if the transaction continues to completion.)^ 5913** 5914** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5915** the opened blob. ^The size of a blob may not be changed by this 5916** interface. Use the [UPDATE] SQL command to change the size of a 5917** blob. 5918** 5919** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5920** and the built-in [zeroblob] SQL function may be used to create a 5921** zero-filled blob to read or write using the incremental-blob interface. 5922** 5923** To avoid a resource leak, every open [BLOB handle] should eventually 5924** be released by a call to [sqlite3_blob_close()]. 5925*/ 5926SQLITE_API int SQLITE_STDCALL sqlite3_blob_open( 5927 sqlite3*, 5928 const char *zDb, 5929 const char *zTable, 5930 const char *zColumn, 5931 sqlite3_int64 iRow, 5932 int flags, 5933 sqlite3_blob **ppBlob 5934); 5935 5936/* 5937** CAPI3REF: Move a BLOB Handle to a New Row 5938** METHOD: sqlite3_blob 5939** 5940** ^This function is used to move an existing blob handle so that it points 5941** to a different row of the same database table. ^The new row is identified 5942** by the rowid value passed as the second argument. Only the row can be 5943** changed. ^The database, table and column on which the blob handle is open 5944** remain the same. Moving an existing blob handle to a new row can be 5945** faster than closing the existing handle and opening a new one. 5946** 5947** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5948** it must exist and there must be either a blob or text value stored in 5949** the nominated column.)^ ^If the new row is not present in the table, or if 5950** it does not contain a blob or text value, or if another error occurs, an 5951** SQLite error code is returned and the blob handle is considered aborted. 5952** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5953** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5954** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5955** always returns zero. 5956** 5957** ^This function sets the database handle error code and message. 5958*/ 5959SQLITE_API int SQLITE_STDCALL sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5960 5961/* 5962** CAPI3REF: Close A BLOB Handle 5963** DESTRUCTOR: sqlite3_blob 5964** 5965** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 5966** unconditionally. Even if this routine returns an error code, the 5967** handle is still closed.)^ 5968** 5969** ^If the blob handle being closed was opened for read-write access, and if 5970** the database is in auto-commit mode and there are no other open read-write 5971** blob handles or active write statements, the current transaction is 5972** committed. ^If an error occurs while committing the transaction, an error 5973** code is returned and the transaction rolled back. 5974** 5975** Calling this function with an argument that is not a NULL pointer or an 5976** open blob handle results in undefined behaviour. ^Calling this routine 5977** with a null pointer (such as would be returned by a failed call to 5978** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 5979** is passed a valid open blob handle, the values returned by the 5980** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 5981*/ 5982SQLITE_API int SQLITE_STDCALL sqlite3_blob_close(sqlite3_blob *); 5983 5984/* 5985** CAPI3REF: Return The Size Of An Open BLOB 5986** METHOD: sqlite3_blob 5987** 5988** ^Returns the size in bytes of the BLOB accessible via the 5989** successfully opened [BLOB handle] in its only argument. ^The 5990** incremental blob I/O routines can only read or overwriting existing 5991** blob content; they cannot change the size of a blob. 5992** 5993** This routine only works on a [BLOB handle] which has been created 5994** by a prior successful call to [sqlite3_blob_open()] and which has not 5995** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5996** to this routine results in undefined and probably undesirable behavior. 5997*/ 5998SQLITE_API int SQLITE_STDCALL sqlite3_blob_bytes(sqlite3_blob *); 5999 6000/* 6001** CAPI3REF: Read Data From A BLOB Incrementally 6002** METHOD: sqlite3_blob 6003** 6004** ^(This function is used to read data from an open [BLOB handle] into a 6005** caller-supplied buffer. N bytes of data are copied into buffer Z 6006** from the open BLOB, starting at offset iOffset.)^ 6007** 6008** ^If offset iOffset is less than N bytes from the end of the BLOB, 6009** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6010** less than zero, [SQLITE_ERROR] is returned and no data is read. 6011** ^The size of the blob (and hence the maximum value of N+iOffset) 6012** can be determined using the [sqlite3_blob_bytes()] interface. 6013** 6014** ^An attempt to read from an expired [BLOB handle] fails with an 6015** error code of [SQLITE_ABORT]. 6016** 6017** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6018** Otherwise, an [error code] or an [extended error code] is returned.)^ 6019** 6020** This routine only works on a [BLOB handle] which has been created 6021** by a prior successful call to [sqlite3_blob_open()] and which has not 6022** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6023** to this routine results in undefined and probably undesirable behavior. 6024** 6025** See also: [sqlite3_blob_write()]. 6026*/ 6027SQLITE_API int SQLITE_STDCALL sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6028 6029/* 6030** CAPI3REF: Write Data Into A BLOB Incrementally 6031** METHOD: sqlite3_blob 6032** 6033** ^(This function is used to write data into an open [BLOB handle] from a 6034** caller-supplied buffer. N bytes of data are copied from the buffer Z 6035** into the open BLOB, starting at offset iOffset.)^ 6036** 6037** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6038** Otherwise, an [error code] or an [extended error code] is returned.)^ 6039** ^Unless SQLITE_MISUSE is returned, this function sets the 6040** [database connection] error code and message accessible via 6041** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6042** 6043** ^If the [BLOB handle] passed as the first argument was not opened for 6044** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6045** this function returns [SQLITE_READONLY]. 6046** 6047** This function may only modify the contents of the BLOB; it is 6048** not possible to increase the size of a BLOB using this API. 6049** ^If offset iOffset is less than N bytes from the end of the BLOB, 6050** [SQLITE_ERROR] is returned and no data is written. The size of the 6051** BLOB (and hence the maximum value of N+iOffset) can be determined 6052** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6053** than zero [SQLITE_ERROR] is returned and no data is written. 6054** 6055** ^An attempt to write to an expired [BLOB handle] fails with an 6056** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6057** before the [BLOB handle] expired are not rolled back by the 6058** expiration of the handle, though of course those changes might 6059** have been overwritten by the statement that expired the BLOB handle 6060** or by other independent statements. 6061** 6062** This routine only works on a [BLOB handle] which has been created 6063** by a prior successful call to [sqlite3_blob_open()] and which has not 6064** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6065** to this routine results in undefined and probably undesirable behavior. 6066** 6067** See also: [sqlite3_blob_read()]. 6068*/ 6069SQLITE_API int SQLITE_STDCALL sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6070 6071/* 6072** CAPI3REF: Virtual File System Objects 6073** 6074** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6075** that SQLite uses to interact 6076** with the underlying operating system. Most SQLite builds come with a 6077** single default VFS that is appropriate for the host computer. 6078** New VFSes can be registered and existing VFSes can be unregistered. 6079** The following interfaces are provided. 6080** 6081** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6082** ^Names are case sensitive. 6083** ^Names are zero-terminated UTF-8 strings. 6084** ^If there is no match, a NULL pointer is returned. 6085** ^If zVfsName is NULL then the default VFS is returned. 6086** 6087** ^New VFSes are registered with sqlite3_vfs_register(). 6088** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6089** ^The same VFS can be registered multiple times without injury. 6090** ^To make an existing VFS into the default VFS, register it again 6091** with the makeDflt flag set. If two different VFSes with the 6092** same name are registered, the behavior is undefined. If a 6093** VFS is registered with a name that is NULL or an empty string, 6094** then the behavior is undefined. 6095** 6096** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6097** ^(If the default VFS is unregistered, another VFS is chosen as 6098** the default. The choice for the new VFS is arbitrary.)^ 6099*/ 6100SQLITE_API sqlite3_vfs *SQLITE_STDCALL sqlite3_vfs_find(const char *zVfsName); 6101SQLITE_API int SQLITE_STDCALL sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6102SQLITE_API int SQLITE_STDCALL sqlite3_vfs_unregister(sqlite3_vfs*); 6103 6104/* 6105** CAPI3REF: Mutexes 6106** 6107** The SQLite core uses these routines for thread 6108** synchronization. Though they are intended for internal 6109** use by SQLite, code that links against SQLite is 6110** permitted to use any of these routines. 6111** 6112** The SQLite source code contains multiple implementations 6113** of these mutex routines. An appropriate implementation 6114** is selected automatically at compile-time. The following 6115** implementations are available in the SQLite core: 6116** 6117** <ul> 6118** <li> SQLITE_MUTEX_PTHREADS 6119** <li> SQLITE_MUTEX_W32 6120** <li> SQLITE_MUTEX_NOOP 6121** </ul> 6122** 6123** The SQLITE_MUTEX_NOOP implementation is a set of routines 6124** that does no real locking and is appropriate for use in 6125** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6126** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6127** and Windows. 6128** 6129** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6130** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6131** implementation is included with the library. In this case the 6132** application must supply a custom mutex implementation using the 6133** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6134** before calling sqlite3_initialize() or any other public sqlite3_ 6135** function that calls sqlite3_initialize(). 6136** 6137** ^The sqlite3_mutex_alloc() routine allocates a new 6138** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6139** routine returns NULL if it is unable to allocate the requested 6140** mutex. The argument to sqlite3_mutex_alloc() must one of these 6141** integer constants: 6142** 6143** <ul> 6144** <li> SQLITE_MUTEX_FAST 6145** <li> SQLITE_MUTEX_RECURSIVE 6146** <li> SQLITE_MUTEX_STATIC_MASTER 6147** <li> SQLITE_MUTEX_STATIC_MEM 6148** <li> SQLITE_MUTEX_STATIC_OPEN 6149** <li> SQLITE_MUTEX_STATIC_PRNG 6150** <li> SQLITE_MUTEX_STATIC_LRU 6151** <li> SQLITE_MUTEX_STATIC_PMEM 6152** <li> SQLITE_MUTEX_STATIC_APP1 6153** <li> SQLITE_MUTEX_STATIC_APP2 6154** <li> SQLITE_MUTEX_STATIC_APP3 6155** <li> SQLITE_MUTEX_STATIC_VFS1 6156** <li> SQLITE_MUTEX_STATIC_VFS2 6157** <li> SQLITE_MUTEX_STATIC_VFS3 6158** </ul> 6159** 6160** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6161** cause sqlite3_mutex_alloc() to create 6162** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6163** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6164** The mutex implementation does not need to make a distinction 6165** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6166** not want to. SQLite will only request a recursive mutex in 6167** cases where it really needs one. If a faster non-recursive mutex 6168** implementation is available on the host platform, the mutex subsystem 6169** might return such a mutex in response to SQLITE_MUTEX_FAST. 6170** 6171** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6172** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6173** a pointer to a static preexisting mutex. ^Nine static mutexes are 6174** used by the current version of SQLite. Future versions of SQLite 6175** may add additional static mutexes. Static mutexes are for internal 6176** use by SQLite only. Applications that use SQLite mutexes should 6177** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6178** SQLITE_MUTEX_RECURSIVE. 6179** 6180** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6181** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6182** returns a different mutex on every call. ^For the static 6183** mutex types, the same mutex is returned on every call that has 6184** the same type number. 6185** 6186** ^The sqlite3_mutex_free() routine deallocates a previously 6187** allocated dynamic mutex. Attempting to deallocate a static 6188** mutex results in undefined behavior. 6189** 6190** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6191** to enter a mutex. ^If another thread is already within the mutex, 6192** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6193** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6194** upon successful entry. ^(Mutexes created using 6195** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6196** In such cases, the 6197** mutex must be exited an equal number of times before another thread 6198** can enter.)^ If the same thread tries to enter any mutex other 6199** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6200** 6201** ^(Some systems (for example, Windows 95) do not support the operation 6202** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6203** will always return SQLITE_BUSY. The SQLite core only ever uses 6204** sqlite3_mutex_try() as an optimization so this is acceptable 6205** behavior.)^ 6206** 6207** ^The sqlite3_mutex_leave() routine exits a mutex that was 6208** previously entered by the same thread. The behavior 6209** is undefined if the mutex is not currently entered by the 6210** calling thread or is not currently allocated. 6211** 6212** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6213** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6214** behave as no-ops. 6215** 6216** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6217*/ 6218SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_mutex_alloc(int); 6219SQLITE_API void SQLITE_STDCALL sqlite3_mutex_free(sqlite3_mutex*); 6220SQLITE_API void SQLITE_STDCALL sqlite3_mutex_enter(sqlite3_mutex*); 6221SQLITE_API int SQLITE_STDCALL sqlite3_mutex_try(sqlite3_mutex*); 6222SQLITE_API void SQLITE_STDCALL sqlite3_mutex_leave(sqlite3_mutex*); 6223 6224/* 6225** CAPI3REF: Mutex Methods Object 6226** 6227** An instance of this structure defines the low-level routines 6228** used to allocate and use mutexes. 6229** 6230** Usually, the default mutex implementations provided by SQLite are 6231** sufficient, however the application has the option of substituting a custom 6232** implementation for specialized deployments or systems for which SQLite 6233** does not provide a suitable implementation. In this case, the application 6234** creates and populates an instance of this structure to pass 6235** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6236** Additionally, an instance of this structure can be used as an 6237** output variable when querying the system for the current mutex 6238** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6239** 6240** ^The xMutexInit method defined by this structure is invoked as 6241** part of system initialization by the sqlite3_initialize() function. 6242** ^The xMutexInit routine is called by SQLite exactly once for each 6243** effective call to [sqlite3_initialize()]. 6244** 6245** ^The xMutexEnd method defined by this structure is invoked as 6246** part of system shutdown by the sqlite3_shutdown() function. The 6247** implementation of this method is expected to release all outstanding 6248** resources obtained by the mutex methods implementation, especially 6249** those obtained by the xMutexInit method. ^The xMutexEnd() 6250** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6251** 6252** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6253** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6254** xMutexNotheld) implement the following interfaces (respectively): 6255** 6256** <ul> 6257** <li> [sqlite3_mutex_alloc()] </li> 6258** <li> [sqlite3_mutex_free()] </li> 6259** <li> [sqlite3_mutex_enter()] </li> 6260** <li> [sqlite3_mutex_try()] </li> 6261** <li> [sqlite3_mutex_leave()] </li> 6262** <li> [sqlite3_mutex_held()] </li> 6263** <li> [sqlite3_mutex_notheld()] </li> 6264** </ul>)^ 6265** 6266** The only difference is that the public sqlite3_XXX functions enumerated 6267** above silently ignore any invocations that pass a NULL pointer instead 6268** of a valid mutex handle. The implementations of the methods defined 6269** by this structure are not required to handle this case, the results 6270** of passing a NULL pointer instead of a valid mutex handle are undefined 6271** (i.e. it is acceptable to provide an implementation that segfaults if 6272** it is passed a NULL pointer). 6273** 6274** The xMutexInit() method must be threadsafe. It must be harmless to 6275** invoke xMutexInit() multiple times within the same process and without 6276** intervening calls to xMutexEnd(). Second and subsequent calls to 6277** xMutexInit() must be no-ops. 6278** 6279** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6280** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6281** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6282** memory allocation for a fast or recursive mutex. 6283** 6284** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6285** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6286** If xMutexInit fails in any way, it is expected to clean up after itself 6287** prior to returning. 6288*/ 6289typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6290struct sqlite3_mutex_methods { 6291 int (*xMutexInit)(void); 6292 int (*xMutexEnd)(void); 6293 sqlite3_mutex *(*xMutexAlloc)(int); 6294 void (*xMutexFree)(sqlite3_mutex *); 6295 void (*xMutexEnter)(sqlite3_mutex *); 6296 int (*xMutexTry)(sqlite3_mutex *); 6297 void (*xMutexLeave)(sqlite3_mutex *); 6298 int (*xMutexHeld)(sqlite3_mutex *); 6299 int (*xMutexNotheld)(sqlite3_mutex *); 6300}; 6301 6302/* 6303** CAPI3REF: Mutex Verification Routines 6304** 6305** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6306** are intended for use inside assert() statements. The SQLite core 6307** never uses these routines except inside an assert() and applications 6308** are advised to follow the lead of the core. The SQLite core only 6309** provides implementations for these routines when it is compiled 6310** with the SQLITE_DEBUG flag. External mutex implementations 6311** are only required to provide these routines if SQLITE_DEBUG is 6312** defined and if NDEBUG is not defined. 6313** 6314** These routines should return true if the mutex in their argument 6315** is held or not held, respectively, by the calling thread. 6316** 6317** The implementation is not required to provide versions of these 6318** routines that actually work. If the implementation does not provide working 6319** versions of these routines, it should at least provide stubs that always 6320** return true so that one does not get spurious assertion failures. 6321** 6322** If the argument to sqlite3_mutex_held() is a NULL pointer then 6323** the routine should return 1. This seems counter-intuitive since 6324** clearly the mutex cannot be held if it does not exist. But 6325** the reason the mutex does not exist is because the build is not 6326** using mutexes. And we do not want the assert() containing the 6327** call to sqlite3_mutex_held() to fail, so a non-zero return is 6328** the appropriate thing to do. The sqlite3_mutex_notheld() 6329** interface should also return 1 when given a NULL pointer. 6330*/ 6331#ifndef NDEBUG 6332SQLITE_API int SQLITE_STDCALL sqlite3_mutex_held(sqlite3_mutex*); 6333SQLITE_API int SQLITE_STDCALL sqlite3_mutex_notheld(sqlite3_mutex*); 6334#endif 6335 6336/* 6337** CAPI3REF: Mutex Types 6338** 6339** The [sqlite3_mutex_alloc()] interface takes a single argument 6340** which is one of these integer constants. 6341** 6342** The set of static mutexes may change from one SQLite release to the 6343** next. Applications that override the built-in mutex logic must be 6344** prepared to accommodate additional static mutexes. 6345*/ 6346#define SQLITE_MUTEX_FAST 0 6347#define SQLITE_MUTEX_RECURSIVE 1 6348#define SQLITE_MUTEX_STATIC_MASTER 2 6349#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6350#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6351#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6352#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 6353#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6354#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6355#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6356#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6357#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6358#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6359#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6360#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6361#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6362 6363/* 6364** CAPI3REF: Retrieve the mutex for a database connection 6365** METHOD: sqlite3 6366** 6367** ^This interface returns a pointer the [sqlite3_mutex] object that 6368** serializes access to the [database connection] given in the argument 6369** when the [threading mode] is Serialized. 6370** ^If the [threading mode] is Single-thread or Multi-thread then this 6371** routine returns a NULL pointer. 6372*/ 6373SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_db_mutex(sqlite3*); 6374 6375/* 6376** CAPI3REF: Low-Level Control Of Database Files 6377** METHOD: sqlite3 6378** 6379** ^The [sqlite3_file_control()] interface makes a direct call to the 6380** xFileControl method for the [sqlite3_io_methods] object associated 6381** with a particular database identified by the second argument. ^The 6382** name of the database is "main" for the main database or "temp" for the 6383** TEMP database, or the name that appears after the AS keyword for 6384** databases that are added using the [ATTACH] SQL command. 6385** ^A NULL pointer can be used in place of "main" to refer to the 6386** main database file. 6387** ^The third and fourth parameters to this routine 6388** are passed directly through to the second and third parameters of 6389** the xFileControl method. ^The return value of the xFileControl 6390** method becomes the return value of this routine. 6391** 6392** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6393** a pointer to the underlying [sqlite3_file] object to be written into 6394** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6395** case is a short-circuit path which does not actually invoke the 6396** underlying sqlite3_io_methods.xFileControl method. 6397** 6398** ^If the second parameter (zDbName) does not match the name of any 6399** open database file, then SQLITE_ERROR is returned. ^This error 6400** code is not remembered and will not be recalled by [sqlite3_errcode()] 6401** or [sqlite3_errmsg()]. The underlying xFileControl method might 6402** also return SQLITE_ERROR. There is no way to distinguish between 6403** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6404** xFileControl method. 6405** 6406** See also: [SQLITE_FCNTL_LOCKSTATE] 6407*/ 6408SQLITE_API int SQLITE_STDCALL sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6409 6410/* 6411** CAPI3REF: Testing Interface 6412** 6413** ^The sqlite3_test_control() interface is used to read out internal 6414** state of SQLite and to inject faults into SQLite for testing 6415** purposes. ^The first parameter is an operation code that determines 6416** the number, meaning, and operation of all subsequent parameters. 6417** 6418** This interface is not for use by applications. It exists solely 6419** for verifying the correct operation of the SQLite library. Depending 6420** on how the SQLite library is compiled, this interface might not exist. 6421** 6422** The details of the operation codes, their meanings, the parameters 6423** they take, and what they do are all subject to change without notice. 6424** Unlike most of the SQLite API, this function is not guaranteed to 6425** operate consistently from one release to the next. 6426*/ 6427SQLITE_API int SQLITE_CDECL sqlite3_test_control(int op, ...); 6428 6429/* 6430** CAPI3REF: Testing Interface Operation Codes 6431** 6432** These constants are the valid operation code parameters used 6433** as the first argument to [sqlite3_test_control()]. 6434** 6435** These parameters and their meanings are subject to change 6436** without notice. These values are for testing purposes only. 6437** Applications should not use any of these parameters or the 6438** [sqlite3_test_control()] interface. 6439*/ 6440#define SQLITE_TESTCTRL_FIRST 5 6441#define SQLITE_TESTCTRL_PRNG_SAVE 5 6442#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6443#define SQLITE_TESTCTRL_PRNG_RESET 7 6444#define SQLITE_TESTCTRL_BITVEC_TEST 8 6445#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6446#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6447#define SQLITE_TESTCTRL_PENDING_BYTE 11 6448#define SQLITE_TESTCTRL_ASSERT 12 6449#define SQLITE_TESTCTRL_ALWAYS 13 6450#define SQLITE_TESTCTRL_RESERVE 14 6451#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6452#define SQLITE_TESTCTRL_ISKEYWORD 16 6453#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6454#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6455#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6456#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6457#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6458#define SQLITE_TESTCTRL_BYTEORDER 22 6459#define SQLITE_TESTCTRL_ISINIT 23 6460#define SQLITE_TESTCTRL_SORTER_MMAP 24 6461#define SQLITE_TESTCTRL_IMPOSTER 25 6462#define SQLITE_TESTCTRL_LAST 25 6463 6464/* 6465** CAPI3REF: SQLite Runtime Status 6466** 6467** ^These interfaces are used to retrieve runtime status information 6468** about the performance of SQLite, and optionally to reset various 6469** highwater marks. ^The first argument is an integer code for 6470** the specific parameter to measure. ^(Recognized integer codes 6471** are of the form [status parameters | SQLITE_STATUS_...].)^ 6472** ^The current value of the parameter is returned into *pCurrent. 6473** ^The highest recorded value is returned in *pHighwater. ^If the 6474** resetFlag is true, then the highest record value is reset after 6475** *pHighwater is written. ^(Some parameters do not record the highest 6476** value. For those parameters 6477** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6478** ^(Other parameters record only the highwater mark and not the current 6479** value. For these latter parameters nothing is written into *pCurrent.)^ 6480** 6481** ^The sqlite3_status() and sqlite3_status64() routines return 6482** SQLITE_OK on success and a non-zero [error code] on failure. 6483** 6484** If either the current value or the highwater mark is too large to 6485** be represented by a 32-bit integer, then the values returned by 6486** sqlite3_status() are undefined. 6487** 6488** See also: [sqlite3_db_status()] 6489*/ 6490SQLITE_API int SQLITE_STDCALL sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6491SQLITE_API int SQLITE_STDCALL sqlite3_status64( 6492 int op, 6493 sqlite3_int64 *pCurrent, 6494 sqlite3_int64 *pHighwater, 6495 int resetFlag 6496); 6497 6498 6499/* 6500** CAPI3REF: Status Parameters 6501** KEYWORDS: {status parameters} 6502** 6503** These integer constants designate various run-time status parameters 6504** that can be returned by [sqlite3_status()]. 6505** 6506** <dl> 6507** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6508** <dd>This parameter is the current amount of memory checked out 6509** using [sqlite3_malloc()], either directly or indirectly. The 6510** figure includes calls made to [sqlite3_malloc()] by the application 6511** and internal memory usage by the SQLite library. Scratch memory 6512** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6513** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6514** this parameter. The amount returned is the sum of the allocation 6515** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6516** 6517** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6518** <dd>This parameter records the largest memory allocation request 6519** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6520** internal equivalents). Only the value returned in the 6521** *pHighwater parameter to [sqlite3_status()] is of interest. 6522** The value written into the *pCurrent parameter is undefined.</dd>)^ 6523** 6524** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6525** <dd>This parameter records the number of separate memory allocations 6526** currently checked out.</dd>)^ 6527** 6528** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6529** <dd>This parameter returns the number of pages used out of the 6530** [pagecache memory allocator] that was configured using 6531** [SQLITE_CONFIG_PAGECACHE]. The 6532** value returned is in pages, not in bytes.</dd>)^ 6533** 6534** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6535** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6536** <dd>This parameter returns the number of bytes of page cache 6537** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6538** buffer and where forced to overflow to [sqlite3_malloc()]. The 6539** returned value includes allocations that overflowed because they 6540** where too large (they were larger than the "sz" parameter to 6541** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6542** no space was left in the page cache.</dd>)^ 6543** 6544** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6545** <dd>This parameter records the largest memory allocation request 6546** handed to [pagecache memory allocator]. Only the value returned in the 6547** *pHighwater parameter to [sqlite3_status()] is of interest. 6548** The value written into the *pCurrent parameter is undefined.</dd>)^ 6549** 6550** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6551** <dd>This parameter returns the number of allocations used out of the 6552** [scratch memory allocator] configured using 6553** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6554** in bytes. Since a single thread may only have one scratch allocation 6555** outstanding at time, this parameter also reports the number of threads 6556** using scratch memory at the same time.</dd>)^ 6557** 6558** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6559** <dd>This parameter returns the number of bytes of scratch memory 6560** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6561** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6562** returned include overflows because the requested allocation was too 6563** larger (that is, because the requested allocation was larger than the 6564** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6565** slots were available. 6566** </dd>)^ 6567** 6568** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6569** <dd>This parameter records the largest memory allocation request 6570** handed to [scratch memory allocator]. Only the value returned in the 6571** *pHighwater parameter to [sqlite3_status()] is of interest. 6572** The value written into the *pCurrent parameter is undefined.</dd>)^ 6573** 6574** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6575** <dd>This parameter records the deepest parser stack. It is only 6576** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6577** </dl> 6578** 6579** New status parameters may be added from time to time. 6580*/ 6581#define SQLITE_STATUS_MEMORY_USED 0 6582#define SQLITE_STATUS_PAGECACHE_USED 1 6583#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6584#define SQLITE_STATUS_SCRATCH_USED 3 6585#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6586#define SQLITE_STATUS_MALLOC_SIZE 5 6587#define SQLITE_STATUS_PARSER_STACK 6 6588#define SQLITE_STATUS_PAGECACHE_SIZE 7 6589#define SQLITE_STATUS_SCRATCH_SIZE 8 6590#define SQLITE_STATUS_MALLOC_COUNT 9 6591 6592/* 6593** CAPI3REF: Database Connection Status 6594** METHOD: sqlite3 6595** 6596** ^This interface is used to retrieve runtime status information 6597** about a single [database connection]. ^The first argument is the 6598** database connection object to be interrogated. ^The second argument 6599** is an integer constant, taken from the set of 6600** [SQLITE_DBSTATUS options], that 6601** determines the parameter to interrogate. The set of 6602** [SQLITE_DBSTATUS options] is likely 6603** to grow in future releases of SQLite. 6604** 6605** ^The current value of the requested parameter is written into *pCur 6606** and the highest instantaneous value is written into *pHiwtr. ^If 6607** the resetFlg is true, then the highest instantaneous value is 6608** reset back down to the current value. 6609** 6610** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6611** non-zero [error code] on failure. 6612** 6613** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6614*/ 6615SQLITE_API int SQLITE_STDCALL sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6616 6617/* 6618** CAPI3REF: Status Parameters for database connections 6619** KEYWORDS: {SQLITE_DBSTATUS options} 6620** 6621** These constants are the available integer "verbs" that can be passed as 6622** the second argument to the [sqlite3_db_status()] interface. 6623** 6624** New verbs may be added in future releases of SQLite. Existing verbs 6625** might be discontinued. Applications should check the return code from 6626** [sqlite3_db_status()] to make sure that the call worked. 6627** The [sqlite3_db_status()] interface will return a non-zero error code 6628** if a discontinued or unsupported verb is invoked. 6629** 6630** <dl> 6631** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6632** <dd>This parameter returns the number of lookaside memory slots currently 6633** checked out.</dd>)^ 6634** 6635** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6636** <dd>This parameter returns the number malloc attempts that were 6637** satisfied using lookaside memory. Only the high-water value is meaningful; 6638** the current value is always zero.)^ 6639** 6640** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6641** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6642** <dd>This parameter returns the number malloc attempts that might have 6643** been satisfied using lookaside memory but failed due to the amount of 6644** memory requested being larger than the lookaside slot size. 6645** Only the high-water value is meaningful; 6646** the current value is always zero.)^ 6647** 6648** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6649** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6650** <dd>This parameter returns the number malloc attempts that might have 6651** been satisfied using lookaside memory but failed due to all lookaside 6652** memory already being in use. 6653** Only the high-water value is meaningful; 6654** the current value is always zero.)^ 6655** 6656** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6657** <dd>This parameter returns the approximate number of bytes of heap 6658** memory used by all pager caches associated with the database connection.)^ 6659** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6660** 6661** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6662** <dd>This parameter returns the approximate number of bytes of heap 6663** memory used to store the schema for all databases associated 6664** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6665** ^The full amount of memory used by the schemas is reported, even if the 6666** schema memory is shared with other database connections due to 6667** [shared cache mode] being enabled. 6668** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6669** 6670** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6671** <dd>This parameter returns the approximate number of bytes of heap 6672** and lookaside memory used by all prepared statements associated with 6673** the database connection.)^ 6674** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6675** </dd> 6676** 6677** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6678** <dd>This parameter returns the number of pager cache hits that have 6679** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6680** is always 0. 6681** </dd> 6682** 6683** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6684** <dd>This parameter returns the number of pager cache misses that have 6685** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6686** is always 0. 6687** </dd> 6688** 6689** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6690** <dd>This parameter returns the number of dirty cache entries that have 6691** been written to disk. Specifically, the number of pages written to the 6692** wal file in wal mode databases, or the number of pages written to the 6693** database file in rollback mode databases. Any pages written as part of 6694** transaction rollback or database recovery operations are not included. 6695** If an IO or other error occurs while writing a page to disk, the effect 6696** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6697** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6698** </dd> 6699** 6700** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 6701** <dd>This parameter returns zero for the current value if and only if 6702** all foreign key constraints (deferred or immediate) have been 6703** resolved.)^ ^The highwater mark is always 0. 6704** </dd> 6705** </dl> 6706*/ 6707#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6708#define SQLITE_DBSTATUS_CACHE_USED 1 6709#define SQLITE_DBSTATUS_SCHEMA_USED 2 6710#define SQLITE_DBSTATUS_STMT_USED 3 6711#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6712#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6713#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6714#define SQLITE_DBSTATUS_CACHE_HIT 7 6715#define SQLITE_DBSTATUS_CACHE_MISS 8 6716#define SQLITE_DBSTATUS_CACHE_WRITE 9 6717#define SQLITE_DBSTATUS_DEFERRED_FKS 10 6718#define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */ 6719 6720 6721/* 6722** CAPI3REF: Prepared Statement Status 6723** METHOD: sqlite3_stmt 6724** 6725** ^(Each prepared statement maintains various 6726** [SQLITE_STMTSTATUS counters] that measure the number 6727** of times it has performed specific operations.)^ These counters can 6728** be used to monitor the performance characteristics of the prepared 6729** statements. For example, if the number of table steps greatly exceeds 6730** the number of table searches or result rows, that would tend to indicate 6731** that the prepared statement is using a full table scan rather than 6732** an index. 6733** 6734** ^(This interface is used to retrieve and reset counter values from 6735** a [prepared statement]. The first argument is the prepared statement 6736** object to be interrogated. The second argument 6737** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6738** to be interrogated.)^ 6739** ^The current value of the requested counter is returned. 6740** ^If the resetFlg is true, then the counter is reset to zero after this 6741** interface call returns. 6742** 6743** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6744*/ 6745SQLITE_API int SQLITE_STDCALL sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6746 6747/* 6748** CAPI3REF: Status Parameters for prepared statements 6749** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6750** 6751** These preprocessor macros define integer codes that name counter 6752** values associated with the [sqlite3_stmt_status()] interface. 6753** The meanings of the various counters are as follows: 6754** 6755** <dl> 6756** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6757** <dd>^This is the number of times that SQLite has stepped forward in 6758** a table as part of a full table scan. Large numbers for this counter 6759** may indicate opportunities for performance improvement through 6760** careful use of indices.</dd> 6761** 6762** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6763** <dd>^This is the number of sort operations that have occurred. 6764** A non-zero value in this counter may indicate an opportunity to 6765** improvement performance through careful use of indices.</dd> 6766** 6767** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6768** <dd>^This is the number of rows inserted into transient indices that 6769** were created automatically in order to help joins run faster. 6770** A non-zero value in this counter may indicate an opportunity to 6771** improvement performance by adding permanent indices that do not 6772** need to be reinitialized each time the statement is run.</dd> 6773** 6774** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 6775** <dd>^This is the number of virtual machine operations executed 6776** by the prepared statement if that number is less than or equal 6777** to 2147483647. The number of virtual machine operations can be 6778** used as a proxy for the total work done by the prepared statement. 6779** If the number of virtual machine operations exceeds 2147483647 6780** then the value returned by this statement status code is undefined. 6781** </dd> 6782** </dl> 6783*/ 6784#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6785#define SQLITE_STMTSTATUS_SORT 2 6786#define SQLITE_STMTSTATUS_AUTOINDEX 3 6787#define SQLITE_STMTSTATUS_VM_STEP 4 6788 6789/* 6790** CAPI3REF: Custom Page Cache Object 6791** 6792** The sqlite3_pcache type is opaque. It is implemented by 6793** the pluggable module. The SQLite core has no knowledge of 6794** its size or internal structure and never deals with the 6795** sqlite3_pcache object except by holding and passing pointers 6796** to the object. 6797** 6798** See [sqlite3_pcache_methods2] for additional information. 6799*/ 6800typedef struct sqlite3_pcache sqlite3_pcache; 6801 6802/* 6803** CAPI3REF: Custom Page Cache Object 6804** 6805** The sqlite3_pcache_page object represents a single page in the 6806** page cache. The page cache will allocate instances of this 6807** object. Various methods of the page cache use pointers to instances 6808** of this object as parameters or as their return value. 6809** 6810** See [sqlite3_pcache_methods2] for additional information. 6811*/ 6812typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6813struct sqlite3_pcache_page { 6814 void *pBuf; /* The content of the page */ 6815 void *pExtra; /* Extra information associated with the page */ 6816}; 6817 6818/* 6819** CAPI3REF: Application Defined Page Cache. 6820** KEYWORDS: {page cache} 6821** 6822** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6823** register an alternative page cache implementation by passing in an 6824** instance of the sqlite3_pcache_methods2 structure.)^ 6825** In many applications, most of the heap memory allocated by 6826** SQLite is used for the page cache. 6827** By implementing a 6828** custom page cache using this API, an application can better control 6829** the amount of memory consumed by SQLite, the way in which 6830** that memory is allocated and released, and the policies used to 6831** determine exactly which parts of a database file are cached and for 6832** how long. 6833** 6834** The alternative page cache mechanism is an 6835** extreme measure that is only needed by the most demanding applications. 6836** The built-in page cache is recommended for most uses. 6837** 6838** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6839** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6840** the application may discard the parameter after the call to 6841** [sqlite3_config()] returns.)^ 6842** 6843** [[the xInit() page cache method]] 6844** ^(The xInit() method is called once for each effective 6845** call to [sqlite3_initialize()])^ 6846** (usually only once during the lifetime of the process). ^(The xInit() 6847** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6848** The intent of the xInit() method is to set up global data structures 6849** required by the custom page cache implementation. 6850** ^(If the xInit() method is NULL, then the 6851** built-in default page cache is used instead of the application defined 6852** page cache.)^ 6853** 6854** [[the xShutdown() page cache method]] 6855** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6856** It can be used to clean up 6857** any outstanding resources before process shutdown, if required. 6858** ^The xShutdown() method may be NULL. 6859** 6860** ^SQLite automatically serializes calls to the xInit method, 6861** so the xInit method need not be threadsafe. ^The 6862** xShutdown method is only called from [sqlite3_shutdown()] so it does 6863** not need to be threadsafe either. All other methods must be threadsafe 6864** in multithreaded applications. 6865** 6866** ^SQLite will never invoke xInit() more than once without an intervening 6867** call to xShutdown(). 6868** 6869** [[the xCreate() page cache methods]] 6870** ^SQLite invokes the xCreate() method to construct a new cache instance. 6871** SQLite will typically create one cache instance for each open database file, 6872** though this is not guaranteed. ^The 6873** first parameter, szPage, is the size in bytes of the pages that must 6874** be allocated by the cache. ^szPage will always a power of two. ^The 6875** second parameter szExtra is a number of bytes of extra storage 6876** associated with each page cache entry. ^The szExtra parameter will 6877** a number less than 250. SQLite will use the 6878** extra szExtra bytes on each page to store metadata about the underlying 6879** database page on disk. The value passed into szExtra depends 6880** on the SQLite version, the target platform, and how SQLite was compiled. 6881** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6882** created will be used to cache database pages of a file stored on disk, or 6883** false if it is used for an in-memory database. The cache implementation 6884** does not have to do anything special based with the value of bPurgeable; 6885** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6886** never invoke xUnpin() except to deliberately delete a page. 6887** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6888** false will always have the "discard" flag set to true. 6889** ^Hence, a cache created with bPurgeable false will 6890** never contain any unpinned pages. 6891** 6892** [[the xCachesize() page cache method]] 6893** ^(The xCachesize() method may be called at any time by SQLite to set the 6894** suggested maximum cache-size (number of pages stored by) the cache 6895** instance passed as the first argument. This is the value configured using 6896** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6897** parameter, the implementation is not required to do anything with this 6898** value; it is advisory only. 6899** 6900** [[the xPagecount() page cache methods]] 6901** The xPagecount() method must return the number of pages currently 6902** stored in the cache, both pinned and unpinned. 6903** 6904** [[the xFetch() page cache methods]] 6905** The xFetch() method locates a page in the cache and returns a pointer to 6906** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6907** The pBuf element of the returned sqlite3_pcache_page object will be a 6908** pointer to a buffer of szPage bytes used to store the content of a 6909** single database page. The pExtra element of sqlite3_pcache_page will be 6910** a pointer to the szExtra bytes of extra storage that SQLite has requested 6911** for each entry in the page cache. 6912** 6913** The page to be fetched is determined by the key. ^The minimum key value 6914** is 1. After it has been retrieved using xFetch, the page is considered 6915** to be "pinned". 6916** 6917** If the requested page is already in the page cache, then the page cache 6918** implementation must return a pointer to the page buffer with its content 6919** intact. If the requested page is not already in the cache, then the 6920** cache implementation should use the value of the createFlag 6921** parameter to help it determined what action to take: 6922** 6923** <table border=1 width=85% align=center> 6924** <tr><th> createFlag <th> Behavior when page is not already in cache 6925** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6926** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6927** Otherwise return NULL. 6928** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6929** NULL if allocating a new page is effectively impossible. 6930** </table> 6931** 6932** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6933** will only use a createFlag of 2 after a prior call with a createFlag of 1 6934** failed.)^ In between the to xFetch() calls, SQLite may 6935** attempt to unpin one or more cache pages by spilling the content of 6936** pinned pages to disk and synching the operating system disk cache. 6937** 6938** [[the xUnpin() page cache method]] 6939** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6940** as its second argument. If the third parameter, discard, is non-zero, 6941** then the page must be evicted from the cache. 6942** ^If the discard parameter is 6943** zero, then the page may be discarded or retained at the discretion of 6944** page cache implementation. ^The page cache implementation 6945** may choose to evict unpinned pages at any time. 6946** 6947** The cache must not perform any reference counting. A single 6948** call to xUnpin() unpins the page regardless of the number of prior calls 6949** to xFetch(). 6950** 6951** [[the xRekey() page cache methods]] 6952** The xRekey() method is used to change the key value associated with the 6953** page passed as the second argument. If the cache 6954** previously contains an entry associated with newKey, it must be 6955** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6956** to be pinned. 6957** 6958** When SQLite calls the xTruncate() method, the cache must discard all 6959** existing cache entries with page numbers (keys) greater than or equal 6960** to the value of the iLimit parameter passed to xTruncate(). If any 6961** of these pages are pinned, they are implicitly unpinned, meaning that 6962** they can be safely discarded. 6963** 6964** [[the xDestroy() page cache method]] 6965** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6966** All resources associated with the specified cache should be freed. ^After 6967** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6968** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6969** functions. 6970** 6971** [[the xShrink() page cache method]] 6972** ^SQLite invokes the xShrink() method when it wants the page cache to 6973** free up as much of heap memory as possible. The page cache implementation 6974** is not obligated to free any memory, but well-behaved implementations should 6975** do their best. 6976*/ 6977typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6978struct sqlite3_pcache_methods2 { 6979 int iVersion; 6980 void *pArg; 6981 int (*xInit)(void*); 6982 void (*xShutdown)(void*); 6983 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6984 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6985 int (*xPagecount)(sqlite3_pcache*); 6986 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6987 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6988 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6989 unsigned oldKey, unsigned newKey); 6990 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6991 void (*xDestroy)(sqlite3_pcache*); 6992 void (*xShrink)(sqlite3_pcache*); 6993}; 6994 6995/* 6996** This is the obsolete pcache_methods object that has now been replaced 6997** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6998** retained in the header file for backwards compatibility only. 6999*/ 7000typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7001struct sqlite3_pcache_methods { 7002 void *pArg; 7003 int (*xInit)(void*); 7004 void (*xShutdown)(void*); 7005 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7006 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7007 int (*xPagecount)(sqlite3_pcache*); 7008 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7009 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7010 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7011 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7012 void (*xDestroy)(sqlite3_pcache*); 7013}; 7014 7015 7016/* 7017** CAPI3REF: Online Backup Object 7018** 7019** The sqlite3_backup object records state information about an ongoing 7020** online backup operation. ^The sqlite3_backup object is created by 7021** a call to [sqlite3_backup_init()] and is destroyed by a call to 7022** [sqlite3_backup_finish()]. 7023** 7024** See Also: [Using the SQLite Online Backup API] 7025*/ 7026typedef struct sqlite3_backup sqlite3_backup; 7027 7028/* 7029** CAPI3REF: Online Backup API. 7030** 7031** The backup API copies the content of one database into another. 7032** It is useful either for creating backups of databases or 7033** for copying in-memory databases to or from persistent files. 7034** 7035** See Also: [Using the SQLite Online Backup API] 7036** 7037** ^SQLite holds a write transaction open on the destination database file 7038** for the duration of the backup operation. 7039** ^The source database is read-locked only while it is being read; 7040** it is not locked continuously for the entire backup operation. 7041** ^Thus, the backup may be performed on a live source database without 7042** preventing other database connections from 7043** reading or writing to the source database while the backup is underway. 7044** 7045** ^(To perform a backup operation: 7046** <ol> 7047** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7048** backup, 7049** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7050** the data between the two databases, and finally 7051** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7052** associated with the backup operation. 7053** </ol>)^ 7054** There should be exactly one call to sqlite3_backup_finish() for each 7055** successful call to sqlite3_backup_init(). 7056** 7057** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7058** 7059** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7060** [database connection] associated with the destination database 7061** and the database name, respectively. 7062** ^The database name is "main" for the main database, "temp" for the 7063** temporary database, or the name specified after the AS keyword in 7064** an [ATTACH] statement for an attached database. 7065** ^The S and M arguments passed to 7066** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7067** and database name of the source database, respectively. 7068** ^The source and destination [database connections] (parameters S and D) 7069** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7070** an error. 7071** 7072** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if 7073** there is already a read or read-write transaction open on the 7074** destination database. 7075** 7076** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7077** returned and an error code and error message are stored in the 7078** destination [database connection] D. 7079** ^The error code and message for the failed call to sqlite3_backup_init() 7080** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7081** [sqlite3_errmsg16()] functions. 7082** ^A successful call to sqlite3_backup_init() returns a pointer to an 7083** [sqlite3_backup] object. 7084** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7085** sqlite3_backup_finish() functions to perform the specified backup 7086** operation. 7087** 7088** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7089** 7090** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7091** the source and destination databases specified by [sqlite3_backup] object B. 7092** ^If N is negative, all remaining source pages are copied. 7093** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7094** are still more pages to be copied, then the function returns [SQLITE_OK]. 7095** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7096** from source to destination, then it returns [SQLITE_DONE]. 7097** ^If an error occurs while running sqlite3_backup_step(B,N), 7098** then an [error code] is returned. ^As well as [SQLITE_OK] and 7099** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7100** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7101** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7102** 7103** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7104** <ol> 7105** <li> the destination database was opened read-only, or 7106** <li> the destination database is using write-ahead-log journaling 7107** and the destination and source page sizes differ, or 7108** <li> the destination database is an in-memory database and the 7109** destination and source page sizes differ. 7110** </ol>)^ 7111** 7112** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7113** the [sqlite3_busy_handler | busy-handler function] 7114** is invoked (if one is specified). ^If the 7115** busy-handler returns non-zero before the lock is available, then 7116** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7117** sqlite3_backup_step() can be retried later. ^If the source 7118** [database connection] 7119** is being used to write to the source database when sqlite3_backup_step() 7120** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7121** case the call to sqlite3_backup_step() can be retried later on. ^(If 7122** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7123** [SQLITE_READONLY] is returned, then 7124** there is no point in retrying the call to sqlite3_backup_step(). These 7125** errors are considered fatal.)^ The application must accept 7126** that the backup operation has failed and pass the backup operation handle 7127** to the sqlite3_backup_finish() to release associated resources. 7128** 7129** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7130** on the destination file. ^The exclusive lock is not released until either 7131** sqlite3_backup_finish() is called or the backup operation is complete 7132** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7133** sqlite3_backup_step() obtains a [shared lock] on the source database that 7134** lasts for the duration of the sqlite3_backup_step() call. 7135** ^Because the source database is not locked between calls to 7136** sqlite3_backup_step(), the source database may be modified mid-way 7137** through the backup process. ^If the source database is modified by an 7138** external process or via a database connection other than the one being 7139** used by the backup operation, then the backup will be automatically 7140** restarted by the next call to sqlite3_backup_step(). ^If the source 7141** database is modified by the using the same database connection as is used 7142** by the backup operation, then the backup database is automatically 7143** updated at the same time. 7144** 7145** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7146** 7147** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7148** application wishes to abandon the backup operation, the application 7149** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7150** ^The sqlite3_backup_finish() interfaces releases all 7151** resources associated with the [sqlite3_backup] object. 7152** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7153** active write-transaction on the destination database is rolled back. 7154** The [sqlite3_backup] object is invalid 7155** and may not be used following a call to sqlite3_backup_finish(). 7156** 7157** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7158** sqlite3_backup_step() errors occurred, regardless or whether or not 7159** sqlite3_backup_step() completed. 7160** ^If an out-of-memory condition or IO error occurred during any prior 7161** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7162** sqlite3_backup_finish() returns the corresponding [error code]. 7163** 7164** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7165** is not a permanent error and does not affect the return value of 7166** sqlite3_backup_finish(). 7167** 7168** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7169** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7170** 7171** ^The sqlite3_backup_remaining() routine returns the number of pages still 7172** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7173** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7174** in the source database at the conclusion of the most recent 7175** sqlite3_backup_step(). 7176** ^(The values returned by these functions are only updated by 7177** sqlite3_backup_step(). If the source database is modified in a way that 7178** changes the size of the source database or the number of pages remaining, 7179** those changes are not reflected in the output of sqlite3_backup_pagecount() 7180** and sqlite3_backup_remaining() until after the next 7181** sqlite3_backup_step().)^ 7182** 7183** <b>Concurrent Usage of Database Handles</b> 7184** 7185** ^The source [database connection] may be used by the application for other 7186** purposes while a backup operation is underway or being initialized. 7187** ^If SQLite is compiled and configured to support threadsafe database 7188** connections, then the source database connection may be used concurrently 7189** from within other threads. 7190** 7191** However, the application must guarantee that the destination 7192** [database connection] is not passed to any other API (by any thread) after 7193** sqlite3_backup_init() is called and before the corresponding call to 7194** sqlite3_backup_finish(). SQLite does not currently check to see 7195** if the application incorrectly accesses the destination [database connection] 7196** and so no error code is reported, but the operations may malfunction 7197** nevertheless. Use of the destination database connection while a 7198** backup is in progress might also also cause a mutex deadlock. 7199** 7200** If running in [shared cache mode], the application must 7201** guarantee that the shared cache used by the destination database 7202** is not accessed while the backup is running. In practice this means 7203** that the application must guarantee that the disk file being 7204** backed up to is not accessed by any connection within the process, 7205** not just the specific connection that was passed to sqlite3_backup_init(). 7206** 7207** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7208** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7209** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7210** APIs are not strictly speaking threadsafe. If they are invoked at the 7211** same time as another thread is invoking sqlite3_backup_step() it is 7212** possible that they return invalid values. 7213*/ 7214SQLITE_API sqlite3_backup *SQLITE_STDCALL sqlite3_backup_init( 7215 sqlite3 *pDest, /* Destination database handle */ 7216 const char *zDestName, /* Destination database name */ 7217 sqlite3 *pSource, /* Source database handle */ 7218 const char *zSourceName /* Source database name */ 7219); 7220SQLITE_API int SQLITE_STDCALL sqlite3_backup_step(sqlite3_backup *p, int nPage); 7221SQLITE_API int SQLITE_STDCALL sqlite3_backup_finish(sqlite3_backup *p); 7222SQLITE_API int SQLITE_STDCALL sqlite3_backup_remaining(sqlite3_backup *p); 7223SQLITE_API int SQLITE_STDCALL sqlite3_backup_pagecount(sqlite3_backup *p); 7224 7225/* 7226** CAPI3REF: Unlock Notification 7227** METHOD: sqlite3 7228** 7229** ^When running in shared-cache mode, a database operation may fail with 7230** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7231** individual tables within the shared-cache cannot be obtained. See 7232** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7233** ^This API may be used to register a callback that SQLite will invoke 7234** when the connection currently holding the required lock relinquishes it. 7235** ^This API is only available if the library was compiled with the 7236** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7237** 7238** See Also: [Using the SQLite Unlock Notification Feature]. 7239** 7240** ^Shared-cache locks are released when a database connection concludes 7241** its current transaction, either by committing it or rolling it back. 7242** 7243** ^When a connection (known as the blocked connection) fails to obtain a 7244** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7245** identity of the database connection (the blocking connection) that 7246** has locked the required resource is stored internally. ^After an 7247** application receives an SQLITE_LOCKED error, it may call the 7248** sqlite3_unlock_notify() method with the blocked connection handle as 7249** the first argument to register for a callback that will be invoked 7250** when the blocking connections current transaction is concluded. ^The 7251** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7252** call that concludes the blocking connections transaction. 7253** 7254** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7255** there is a chance that the blocking connection will have already 7256** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7257** If this happens, then the specified callback is invoked immediately, 7258** from within the call to sqlite3_unlock_notify().)^ 7259** 7260** ^If the blocked connection is attempting to obtain a write-lock on a 7261** shared-cache table, and more than one other connection currently holds 7262** a read-lock on the same table, then SQLite arbitrarily selects one of 7263** the other connections to use as the blocking connection. 7264** 7265** ^(There may be at most one unlock-notify callback registered by a 7266** blocked connection. If sqlite3_unlock_notify() is called when the 7267** blocked connection already has a registered unlock-notify callback, 7268** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7269** called with a NULL pointer as its second argument, then any existing 7270** unlock-notify callback is canceled. ^The blocked connections 7271** unlock-notify callback may also be canceled by closing the blocked 7272** connection using [sqlite3_close()]. 7273** 7274** The unlock-notify callback is not reentrant. If an application invokes 7275** any sqlite3_xxx API functions from within an unlock-notify callback, a 7276** crash or deadlock may be the result. 7277** 7278** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7279** returns SQLITE_OK. 7280** 7281** <b>Callback Invocation Details</b> 7282** 7283** When an unlock-notify callback is registered, the application provides a 7284** single void* pointer that is passed to the callback when it is invoked. 7285** However, the signature of the callback function allows SQLite to pass 7286** it an array of void* context pointers. The first argument passed to 7287** an unlock-notify callback is a pointer to an array of void* pointers, 7288** and the second is the number of entries in the array. 7289** 7290** When a blocking connections transaction is concluded, there may be 7291** more than one blocked connection that has registered for an unlock-notify 7292** callback. ^If two or more such blocked connections have specified the 7293** same callback function, then instead of invoking the callback function 7294** multiple times, it is invoked once with the set of void* context pointers 7295** specified by the blocked connections bundled together into an array. 7296** This gives the application an opportunity to prioritize any actions 7297** related to the set of unblocked database connections. 7298** 7299** <b>Deadlock Detection</b> 7300** 7301** Assuming that after registering for an unlock-notify callback a 7302** database waits for the callback to be issued before taking any further 7303** action (a reasonable assumption), then using this API may cause the 7304** application to deadlock. For example, if connection X is waiting for 7305** connection Y's transaction to be concluded, and similarly connection 7306** Y is waiting on connection X's transaction, then neither connection 7307** will proceed and the system may remain deadlocked indefinitely. 7308** 7309** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7310** detection. ^If a given call to sqlite3_unlock_notify() would put the 7311** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7312** unlock-notify callback is registered. The system is said to be in 7313** a deadlocked state if connection A has registered for an unlock-notify 7314** callback on the conclusion of connection B's transaction, and connection 7315** B has itself registered for an unlock-notify callback when connection 7316** A's transaction is concluded. ^Indirect deadlock is also detected, so 7317** the system is also considered to be deadlocked if connection B has 7318** registered for an unlock-notify callback on the conclusion of connection 7319** C's transaction, where connection C is waiting on connection A. ^Any 7320** number of levels of indirection are allowed. 7321** 7322** <b>The "DROP TABLE" Exception</b> 7323** 7324** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7325** always appropriate to call sqlite3_unlock_notify(). There is however, 7326** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7327** SQLite checks if there are any currently executing SELECT statements 7328** that belong to the same connection. If there are, SQLITE_LOCKED is 7329** returned. In this case there is no "blocking connection", so invoking 7330** sqlite3_unlock_notify() results in the unlock-notify callback being 7331** invoked immediately. If the application then re-attempts the "DROP TABLE" 7332** or "DROP INDEX" query, an infinite loop might be the result. 7333** 7334** One way around this problem is to check the extended error code returned 7335** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7336** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7337** the special "DROP TABLE/INDEX" case, the extended error code is just 7338** SQLITE_LOCKED.)^ 7339*/ 7340SQLITE_API int SQLITE_STDCALL sqlite3_unlock_notify( 7341 sqlite3 *pBlocked, /* Waiting connection */ 7342 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7343 void *pNotifyArg /* Argument to pass to xNotify */ 7344); 7345 7346 7347/* 7348** CAPI3REF: String Comparison 7349** 7350** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7351** and extensions to compare the contents of two buffers containing UTF-8 7352** strings in a case-independent fashion, using the same definition of "case 7353** independence" that SQLite uses internally when comparing identifiers. 7354*/ 7355SQLITE_API int SQLITE_STDCALL sqlite3_stricmp(const char *, const char *); 7356SQLITE_API int SQLITE_STDCALL sqlite3_strnicmp(const char *, const char *, int); 7357 7358/* 7359** CAPI3REF: String Globbing 7360* 7361** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches 7362** the glob pattern P, and it returns non-zero if string X does not match 7363** the glob pattern P. ^The definition of glob pattern matching used in 7364** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7365** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case 7366** sensitive. 7367** 7368** Note that this routine returns zero on a match and non-zero if the strings 7369** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7370*/ 7371SQLITE_API int SQLITE_STDCALL sqlite3_strglob(const char *zGlob, const char *zStr); 7372 7373/* 7374** CAPI3REF: Error Logging Interface 7375** 7376** ^The [sqlite3_log()] interface writes a message into the [error log] 7377** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7378** ^If logging is enabled, the zFormat string and subsequent arguments are 7379** used with [sqlite3_snprintf()] to generate the final output string. 7380** 7381** The sqlite3_log() interface is intended for use by extensions such as 7382** virtual tables, collating functions, and SQL functions. While there is 7383** nothing to prevent an application from calling sqlite3_log(), doing so 7384** is considered bad form. 7385** 7386** The zFormat string must not be NULL. 7387** 7388** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7389** will not use dynamically allocated memory. The log message is stored in 7390** a fixed-length buffer on the stack. If the log message is longer than 7391** a few hundred characters, it will be truncated to the length of the 7392** buffer. 7393*/ 7394SQLITE_API void SQLITE_CDECL sqlite3_log(int iErrCode, const char *zFormat, ...); 7395 7396/* 7397** CAPI3REF: Write-Ahead Log Commit Hook 7398** METHOD: sqlite3 7399** 7400** ^The [sqlite3_wal_hook()] function is used to register a callback that 7401** is invoked each time data is committed to a database in wal mode. 7402** 7403** ^(The callback is invoked by SQLite after the commit has taken place and 7404** the associated write-lock on the database released)^, so the implementation 7405** may read, write or [checkpoint] the database as required. 7406** 7407** ^The first parameter passed to the callback function when it is invoked 7408** is a copy of the third parameter passed to sqlite3_wal_hook() when 7409** registering the callback. ^The second is a copy of the database handle. 7410** ^The third parameter is the name of the database that was written to - 7411** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7412** is the number of pages currently in the write-ahead log file, 7413** including those that were just committed. 7414** 7415** The callback function should normally return [SQLITE_OK]. ^If an error 7416** code is returned, that error will propagate back up through the 7417** SQLite code base to cause the statement that provoked the callback 7418** to report an error, though the commit will have still occurred. If the 7419** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7420** that does not correspond to any valid SQLite error code, the results 7421** are undefined. 7422** 7423** A single database handle may have at most a single write-ahead log callback 7424** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7425** previously registered write-ahead log callback. ^Note that the 7426** [sqlite3_wal_autocheckpoint()] interface and the 7427** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7428** those overwrite any prior [sqlite3_wal_hook()] settings. 7429*/ 7430SQLITE_API void *SQLITE_STDCALL sqlite3_wal_hook( 7431 sqlite3*, 7432 int(*)(void *,sqlite3*,const char*,int), 7433 void* 7434); 7435 7436/* 7437** CAPI3REF: Configure an auto-checkpoint 7438** METHOD: sqlite3 7439** 7440** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 7441** [sqlite3_wal_hook()] that causes any database on [database connection] D 7442** to automatically [checkpoint] 7443** after committing a transaction if there are N or 7444** more frames in the [write-ahead log] file. ^Passing zero or 7445** a negative value as the nFrame parameter disables automatic 7446** checkpoints entirely. 7447** 7448** ^The callback registered by this function replaces any existing callback 7449** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 7450** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 7451** configured by this function. 7452** 7453** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 7454** from SQL. 7455** 7456** ^Checkpoints initiated by this mechanism are 7457** [sqlite3_wal_checkpoint_v2|PASSIVE]. 7458** 7459** ^Every new [database connection] defaults to having the auto-checkpoint 7460** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 7461** pages. The use of this interface 7462** is only necessary if the default setting is found to be suboptimal 7463** for a particular application. 7464*/ 7465SQLITE_API int SQLITE_STDCALL sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 7466 7467/* 7468** CAPI3REF: Checkpoint a database 7469** METHOD: sqlite3 7470** 7471** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 7472** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 7473** 7474** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 7475** [write-ahead log] for database X on [database connection] D to be 7476** transferred into the database file and for the write-ahead log to 7477** be reset. See the [checkpointing] documentation for addition 7478** information. 7479** 7480** This interface used to be the only way to cause a checkpoint to 7481** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 7482** interface was added. This interface is retained for backwards 7483** compatibility and as a convenience for applications that need to manually 7484** start a callback but which do not need the full power (and corresponding 7485** complication) of [sqlite3_wal_checkpoint_v2()]. 7486*/ 7487SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 7488 7489/* 7490** CAPI3REF: Checkpoint a database 7491** METHOD: sqlite3 7492** 7493** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 7494** operation on database X of [database connection] D in mode M. Status 7495** information is written back into integers pointed to by L and C.)^ 7496** ^(The M parameter must be a valid [checkpoint mode]:)^ 7497** 7498** <dl> 7499** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7500** ^Checkpoint as many frames as possible without waiting for any database 7501** readers or writers to finish, then sync the database file if all frames 7502** in the log were checkpointed. ^The [busy-handler callback] 7503** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 7504** ^On the other hand, passive mode might leave the checkpoint unfinished 7505** if there are concurrent readers or writers. 7506** 7507** <dt>SQLITE_CHECKPOINT_FULL<dd> 7508** ^This mode blocks (it invokes the 7509** [sqlite3_busy_handler|busy-handler callback]) until there is no 7510** database writer and all readers are reading from the most recent database 7511** snapshot. ^It then checkpoints all frames in the log file and syncs the 7512** database file. ^This mode blocks new database writers while it is pending, 7513** but new database readers are allowed to continue unimpeded. 7514** 7515** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7516** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 7517** that after checkpointing the log file it blocks (calls the 7518** [busy-handler callback]) 7519** until all readers are reading from the database file only. ^This ensures 7520** that the next writer will restart the log file from the beginning. 7521** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 7522** database writer attempts while it is pending, but does not impede readers. 7523** 7524** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 7525** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 7526** addition that it also truncates the log file to zero bytes just prior 7527** to a successful return. 7528** </dl> 7529** 7530** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 7531** the log file or to -1 if the checkpoint could not run because 7532** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 7533** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 7534** log file (including any that were already checkpointed before the function 7535** was called) or to -1 if the checkpoint could not run due to an error or 7536** because the database is not in WAL mode. ^Note that upon successful 7537** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 7538** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 7539** 7540** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 7541** any other process is running a checkpoint operation at the same time, the 7542** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 7543** busy-handler configured, it will not be invoked in this case. 7544** 7545** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 7546** exclusive "writer" lock on the database file. ^If the writer lock cannot be 7547** obtained immediately, and a busy-handler is configured, it is invoked and 7548** the writer lock retried until either the busy-handler returns 0 or the lock 7549** is successfully obtained. ^The busy-handler is also invoked while waiting for 7550** database readers as described above. ^If the busy-handler returns 0 before 7551** the writer lock is obtained or while waiting for database readers, the 7552** checkpoint operation proceeds from that point in the same way as 7553** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7554** without blocking any further. ^SQLITE_BUSY is returned in this case. 7555** 7556** ^If parameter zDb is NULL or points to a zero length string, then the 7557** specified operation is attempted on all WAL databases [attached] to 7558** [database connection] db. In this case the 7559** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 7560** an SQLITE_BUSY error is encountered when processing one or more of the 7561** attached WAL databases, the operation is still attempted on any remaining 7562** attached databases and SQLITE_BUSY is returned at the end. ^If any other 7563** error occurs while processing an attached database, processing is abandoned 7564** and the error code is returned to the caller immediately. ^If no error 7565** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7566** databases, SQLITE_OK is returned. 7567** 7568** ^If database zDb is the name of an attached database that is not in WAL 7569** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 7570** zDb is not NULL (or a zero length string) and is not the name of any 7571** attached database, SQLITE_ERROR is returned to the caller. 7572** 7573** ^Unless it returns SQLITE_MISUSE, 7574** the sqlite3_wal_checkpoint_v2() interface 7575** sets the error information that is queried by 7576** [sqlite3_errcode()] and [sqlite3_errmsg()]. 7577** 7578** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 7579** from SQL. 7580*/ 7581SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint_v2( 7582 sqlite3 *db, /* Database handle */ 7583 const char *zDb, /* Name of attached database (or NULL) */ 7584 int eMode, /* SQLITE_CHECKPOINT_* value */ 7585 int *pnLog, /* OUT: Size of WAL log in frames */ 7586 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7587); 7588 7589/* 7590** CAPI3REF: Checkpoint Mode Values 7591** KEYWORDS: {checkpoint mode} 7592** 7593** These constants define all valid values for the "checkpoint mode" passed 7594** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 7595** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 7596** meaning of each of these checkpoint modes. 7597*/ 7598#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 7599#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 7600#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 7601#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 7602 7603/* 7604** CAPI3REF: Virtual Table Interface Configuration 7605** 7606** This function may be called by either the [xConnect] or [xCreate] method 7607** of a [virtual table] implementation to configure 7608** various facets of the virtual table interface. 7609** 7610** If this interface is invoked outside the context of an xConnect or 7611** xCreate virtual table method then the behavior is undefined. 7612** 7613** At present, there is only one option that may be configured using 7614** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7615** may be added in the future. 7616*/ 7617SQLITE_API int SQLITE_CDECL sqlite3_vtab_config(sqlite3*, int op, ...); 7618 7619/* 7620** CAPI3REF: Virtual Table Configuration Options 7621** 7622** These macros define the various options to the 7623** [sqlite3_vtab_config()] interface that [virtual table] implementations 7624** can use to customize and optimize their behavior. 7625** 7626** <dl> 7627** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7628** <dd>Calls of the form 7629** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7630** where X is an integer. If X is zero, then the [virtual table] whose 7631** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7632** support constraints. In this configuration (which is the default) if 7633** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7634** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7635** specified as part of the users SQL statement, regardless of the actual 7636** ON CONFLICT mode specified. 7637** 7638** If X is non-zero, then the virtual table implementation guarantees 7639** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7640** any modifications to internal or persistent data structures have been made. 7641** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7642** is able to roll back a statement or database transaction, and abandon 7643** or continue processing the current SQL statement as appropriate. 7644** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7645** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7646** had been ABORT. 7647** 7648** Virtual table implementations that are required to handle OR REPLACE 7649** must do so within the [xUpdate] method. If a call to the 7650** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7651** CONFLICT policy is REPLACE, the virtual table implementation should 7652** silently replace the appropriate rows within the xUpdate callback and 7653** return SQLITE_OK. Or, if this is not possible, it may return 7654** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7655** constraint handling. 7656** </dl> 7657*/ 7658#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7659 7660/* 7661** CAPI3REF: Determine The Virtual Table Conflict Policy 7662** 7663** This function may only be called from within a call to the [xUpdate] method 7664** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7665** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7666** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7667** of the SQL statement that triggered the call to the [xUpdate] method of the 7668** [virtual table]. 7669*/ 7670SQLITE_API int SQLITE_STDCALL sqlite3_vtab_on_conflict(sqlite3 *); 7671 7672/* 7673** CAPI3REF: Conflict resolution modes 7674** KEYWORDS: {conflict resolution mode} 7675** 7676** These constants are returned by [sqlite3_vtab_on_conflict()] to 7677** inform a [virtual table] implementation what the [ON CONFLICT] mode 7678** is for the SQL statement being evaluated. 7679** 7680** Note that the [SQLITE_IGNORE] constant is also used as a potential 7681** return value from the [sqlite3_set_authorizer()] callback and that 7682** [SQLITE_ABORT] is also a [result code]. 7683*/ 7684#define SQLITE_ROLLBACK 1 7685/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7686#define SQLITE_FAIL 3 7687/* #define SQLITE_ABORT 4 // Also an error code */ 7688#define SQLITE_REPLACE 5 7689 7690/* 7691** CAPI3REF: Prepared Statement Scan Status Opcodes 7692** KEYWORDS: {scanstatus options} 7693** 7694** The following constants can be used for the T parameter to the 7695** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 7696** different metric for sqlite3_stmt_scanstatus() to return. 7697** 7698** When the value returned to V is a string, space to hold that string is 7699** managed by the prepared statement S and will be automatically freed when 7700** S is finalized. 7701** 7702** <dl> 7703** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 7704** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 7705** set to the total number of times that the X-th loop has run.</dd> 7706** 7707** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 7708** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 7709** to the total number of rows examined by all iterations of the X-th loop.</dd> 7710** 7711** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 7712** <dd>^The "double" variable pointed to by the T parameter will be set to the 7713** query planner's estimate for the average number of rows output from each 7714** iteration of the X-th loop. If the query planner's estimates was accurate, 7715** then this value will approximate the quotient NVISIT/NLOOP and the 7716** product of this value for all prior loops with the same SELECTID will 7717** be the NLOOP value for the current loop. 7718** 7719** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 7720** <dd>^The "const char *" variable pointed to by the T parameter will be set 7721** to a zero-terminated UTF-8 string containing the name of the index or table 7722** used for the X-th loop. 7723** 7724** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 7725** <dd>^The "const char *" variable pointed to by the T parameter will be set 7726** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 7727** description for the X-th loop. 7728** 7729** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 7730** <dd>^The "int" variable pointed to by the T parameter will be set to the 7731** "select-id" for the X-th loop. The select-id identifies which query or 7732** subquery the loop is part of. The main query has a select-id of zero. 7733** The select-id is the same value as is output in the first column 7734** of an [EXPLAIN QUERY PLAN] query. 7735** </dl> 7736*/ 7737#define SQLITE_SCANSTAT_NLOOP 0 7738#define SQLITE_SCANSTAT_NVISIT 1 7739#define SQLITE_SCANSTAT_EST 2 7740#define SQLITE_SCANSTAT_NAME 3 7741#define SQLITE_SCANSTAT_EXPLAIN 4 7742#define SQLITE_SCANSTAT_SELECTID 5 7743 7744/* 7745** CAPI3REF: Prepared Statement Scan Status 7746** METHOD: sqlite3_stmt 7747** 7748** This interface returns information about the predicted and measured 7749** performance for pStmt. Advanced applications can use this 7750** interface to compare the predicted and the measured performance and 7751** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 7752** 7753** Since this interface is expected to be rarely used, it is only 7754** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 7755** compile-time option. 7756** 7757** The "iScanStatusOp" parameter determines which status information to return. 7758** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 7759** of this interface is undefined. 7760** ^The requested measurement is written into a variable pointed to by 7761** the "pOut" parameter. 7762** Parameter "idx" identifies the specific loop to retrieve statistics for. 7763** Loops are numbered starting from zero. ^If idx is out of range - less than 7764** zero or greater than or equal to the total number of loops used to implement 7765** the statement - a non-zero value is returned and the variable that pOut 7766** points to is unchanged. 7767** 7768** ^Statistics might not be available for all loops in all statements. ^In cases 7769** where there exist loops with no available statistics, this function behaves 7770** as if the loop did not exist - it returns non-zero and leave the variable 7771** that pOut points to unchanged. 7772** 7773** See also: [sqlite3_stmt_scanstatus_reset()] 7774*/ 7775SQLITE_API int SQLITE_STDCALL sqlite3_stmt_scanstatus( 7776 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 7777 int idx, /* Index of loop to report on */ 7778 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 7779 void *pOut /* Result written here */ 7780); 7781 7782/* 7783** CAPI3REF: Zero Scan-Status Counters 7784** METHOD: sqlite3_stmt 7785** 7786** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 7787** 7788** This API is only available if the library is built with pre-processor 7789** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 7790*/ 7791SQLITE_API void SQLITE_STDCALL sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 7792 7793 7794/* 7795** Undo the hack that converts floating point types to integer for 7796** builds on processors without floating point support. 7797*/ 7798#ifdef SQLITE_OMIT_FLOATING_POINT 7799# undef double 7800#endif 7801 7802#ifdef __cplusplus 7803} /* End of the 'extern "C"' block */ 7804#endif 7805#endif /* _SQLITE3_H_ */ 7806 7807/* 7808** 2010 August 30 7809** 7810** The author disclaims copyright to this source code. In place of 7811** a legal notice, here is a blessing: 7812** 7813** May you do good and not evil. 7814** May you find forgiveness for yourself and forgive others. 7815** May you share freely, never taking more than you give. 7816** 7817************************************************************************* 7818*/ 7819 7820#ifndef _SQLITE3RTREE_H_ 7821#define _SQLITE3RTREE_H_ 7822 7823 7824#ifdef __cplusplus 7825extern "C" { 7826#endif 7827 7828typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry; 7829typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info; 7830 7831/* The double-precision datatype used by RTree depends on the 7832** SQLITE_RTREE_INT_ONLY compile-time option. 7833*/ 7834#ifdef SQLITE_RTREE_INT_ONLY 7835 typedef sqlite3_int64 sqlite3_rtree_dbl; 7836#else 7837 typedef double sqlite3_rtree_dbl; 7838#endif 7839 7840/* 7841** Register a geometry callback named zGeom that can be used as part of an 7842** R-Tree geometry query as follows: 7843** 7844** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...) 7845*/ 7846SQLITE_API int SQLITE_STDCALL sqlite3_rtree_geometry_callback( 7847 sqlite3 *db, 7848 const char *zGeom, 7849 int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*), 7850 void *pContext 7851); 7852 7853 7854/* 7855** A pointer to a structure of the following type is passed as the first 7856** argument to callbacks registered using rtree_geometry_callback(). 7857*/ 7858struct sqlite3_rtree_geometry { 7859 void *pContext; /* Copy of pContext passed to s_r_g_c() */ 7860 int nParam; /* Size of array aParam[] */ 7861 sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */ 7862 void *pUser; /* Callback implementation user data */ 7863 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */ 7864}; 7865 7866/* 7867** Register a 2nd-generation geometry callback named zScore that can be 7868** used as part of an R-Tree geometry query as follows: 7869** 7870** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...) 7871*/ 7872SQLITE_API int SQLITE_STDCALL sqlite3_rtree_query_callback( 7873 sqlite3 *db, 7874 const char *zQueryFunc, 7875 int (*xQueryFunc)(sqlite3_rtree_query_info*), 7876 void *pContext, 7877 void (*xDestructor)(void*) 7878); 7879 7880 7881/* 7882** A pointer to a structure of the following type is passed as the 7883** argument to scored geometry callback registered using 7884** sqlite3_rtree_query_callback(). 7885** 7886** Note that the first 5 fields of this structure are identical to 7887** sqlite3_rtree_geometry. This structure is a subclass of 7888** sqlite3_rtree_geometry. 7889*/ 7890struct sqlite3_rtree_query_info { 7891 void *pContext; /* pContext from when function registered */ 7892 int nParam; /* Number of function parameters */ 7893 sqlite3_rtree_dbl *aParam; /* value of function parameters */ 7894 void *pUser; /* callback can use this, if desired */ 7895 void (*xDelUser)(void*); /* function to free pUser */ 7896 sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */ 7897 unsigned int *anQueue; /* Number of pending entries in the queue */ 7898 int nCoord; /* Number of coordinates */ 7899 int iLevel; /* Level of current node or entry */ 7900 int mxLevel; /* The largest iLevel value in the tree */ 7901 sqlite3_int64 iRowid; /* Rowid for current entry */ 7902 sqlite3_rtree_dbl rParentScore; /* Score of parent node */ 7903 int eParentWithin; /* Visibility of parent node */ 7904 int eWithin; /* OUT: Visiblity */ 7905 sqlite3_rtree_dbl rScore; /* OUT: Write the score here */ 7906 /* The following fields are only available in 3.8.11 and later */ 7907 sqlite3_value **apSqlParam; /* Original SQL values of parameters */ 7908}; 7909 7910/* 7911** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin. 7912*/ 7913#define NOT_WITHIN 0 /* Object completely outside of query region */ 7914#define PARTLY_WITHIN 1 /* Object partially overlaps query region */ 7915#define FULLY_WITHIN 2 /* Object fully contained within query region */ 7916 7917 7918#ifdef __cplusplus 7919} /* end of the 'extern "C"' block */ 7920#endif 7921 7922#endif /* ifndef _SQLITE3RTREE_H_ */ 7923 7924/* 7925** 2014 May 31 7926** 7927** The author disclaims copyright to this source code. In place of 7928** a legal notice, here is a blessing: 7929** 7930** May you do good and not evil. 7931** May you find forgiveness for yourself and forgive others. 7932** May you share freely, never taking more than you give. 7933** 7934****************************************************************************** 7935** 7936** Interfaces to extend FTS5. Using the interfaces defined in this file, 7937** FTS5 may be extended with: 7938** 7939** * custom tokenizers, and 7940** * custom auxiliary functions. 7941*/ 7942 7943 7944#ifndef _FTS5_H 7945#define _FTS5_H 7946 7947 7948#ifdef __cplusplus 7949extern "C" { 7950#endif 7951 7952/************************************************************************* 7953** CUSTOM AUXILIARY FUNCTIONS 7954** 7955** Virtual table implementations may overload SQL functions by implementing 7956** the sqlite3_module.xFindFunction() method. 7957*/ 7958 7959typedef struct Fts5ExtensionApi Fts5ExtensionApi; 7960typedef struct Fts5Context Fts5Context; 7961typedef struct Fts5PhraseIter Fts5PhraseIter; 7962 7963typedef void (*fts5_extension_function)( 7964 const Fts5ExtensionApi *pApi, /* API offered by current FTS version */ 7965 Fts5Context *pFts, /* First arg to pass to pApi functions */ 7966 sqlite3_context *pCtx, /* Context for returning result/error */ 7967 int nVal, /* Number of values in apVal[] array */ 7968 sqlite3_value **apVal /* Array of trailing arguments */ 7969); 7970 7971struct Fts5PhraseIter { 7972 const unsigned char *a; 7973 const unsigned char *b; 7974}; 7975 7976/* 7977** EXTENSION API FUNCTIONS 7978** 7979** xUserData(pFts): 7980** Return a copy of the context pointer the extension function was 7981** registered with. 7982** 7983** xColumnTotalSize(pFts, iCol, pnToken): 7984** If parameter iCol is less than zero, set output variable *pnToken 7985** to the total number of tokens in the FTS5 table. Or, if iCol is 7986** non-negative but less than the number of columns in the table, return 7987** the total number of tokens in column iCol, considering all rows in 7988** the FTS5 table. 7989** 7990** If parameter iCol is greater than or equal to the number of columns 7991** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g. 7992** an OOM condition or IO error), an appropriate SQLite error code is 7993** returned. 7994** 7995** xColumnCount(pFts): 7996** Return the number of columns in the table. 7997** 7998** xColumnSize(pFts, iCol, pnToken): 7999** If parameter iCol is less than zero, set output variable *pnToken 8000** to the total number of tokens in the current row. Or, if iCol is 8001** non-negative but less than the number of columns in the table, set 8002** *pnToken to the number of tokens in column iCol of the current row. 8003** 8004** If parameter iCol is greater than or equal to the number of columns 8005** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g. 8006** an OOM condition or IO error), an appropriate SQLite error code is 8007** returned. 8008** 8009** xColumnText: 8010** This function attempts to retrieve the text of column iCol of the 8011** current document. If successful, (*pz) is set to point to a buffer 8012** containing the text in utf-8 encoding, (*pn) is set to the size in bytes 8013** (not characters) of the buffer and SQLITE_OK is returned. Otherwise, 8014** if an error occurs, an SQLite error code is returned and the final values 8015** of (*pz) and (*pn) are undefined. 8016** 8017** xPhraseCount: 8018** Returns the number of phrases in the current query expression. 8019** 8020** xPhraseSize: 8021** Returns the number of tokens in phrase iPhrase of the query. Phrases 8022** are numbered starting from zero. 8023** 8024** xInstCount: 8025** Set *pnInst to the total number of occurrences of all phrases within 8026** the query within the current row. Return SQLITE_OK if successful, or 8027** an error code (i.e. SQLITE_NOMEM) if an error occurs. 8028** 8029** xInst: 8030** Query for the details of phrase match iIdx within the current row. 8031** Phrase matches are numbered starting from zero, so the iIdx argument 8032** should be greater than or equal to zero and smaller than the value 8033** output by xInstCount(). 8034** 8035** Returns SQLITE_OK if successful, or an error code (i.e. SQLITE_NOMEM) 8036** if an error occurs. 8037** 8038** xRowid: 8039** Returns the rowid of the current row. 8040** 8041** xTokenize: 8042** Tokenize text using the tokenizer belonging to the FTS5 table. 8043** 8044** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback): 8045** This API function is used to query the FTS table for phrase iPhrase 8046** of the current query. Specifically, a query equivalent to: 8047** 8048** ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid 8049** 8050** with $p set to a phrase equivalent to the phrase iPhrase of the 8051** current query is executed. For each row visited, the callback function 8052** passed as the fourth argument is invoked. The context and API objects 8053** passed to the callback function may be used to access the properties of 8054** each matched row. Invoking Api.xUserData() returns a copy of the pointer 8055** passed as the third argument to pUserData. 8056** 8057** If the callback function returns any value other than SQLITE_OK, the 8058** query is abandoned and the xQueryPhrase function returns immediately. 8059** If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK. 8060** Otherwise, the error code is propagated upwards. 8061** 8062** If the query runs to completion without incident, SQLITE_OK is returned. 8063** Or, if some error occurs before the query completes or is aborted by 8064** the callback, an SQLite error code is returned. 8065** 8066** 8067** xSetAuxdata(pFts5, pAux, xDelete) 8068** 8069** Save the pointer passed as the second argument as the extension functions 8070** "auxiliary data". The pointer may then be retrieved by the current or any 8071** future invocation of the same fts5 extension function made as part of 8072** of the same MATCH query using the xGetAuxdata() API. 8073** 8074** Each extension function is allocated a single auxiliary data slot for 8075** each FTS query (MATCH expression). If the extension function is invoked 8076** more than once for a single FTS query, then all invocations share a 8077** single auxiliary data context. 8078** 8079** If there is already an auxiliary data pointer when this function is 8080** invoked, then it is replaced by the new pointer. If an xDelete callback 8081** was specified along with the original pointer, it is invoked at this 8082** point. 8083** 8084** The xDelete callback, if one is specified, is also invoked on the 8085** auxiliary data pointer after the FTS5 query has finished. 8086** 8087** If an error (e.g. an OOM condition) occurs within this function, an 8088** the auxiliary data is set to NULL and an error code returned. If the 8089** xDelete parameter was not NULL, it is invoked on the auxiliary data 8090** pointer before returning. 8091** 8092** 8093** xGetAuxdata(pFts5, bClear) 8094** 8095** Returns the current auxiliary data pointer for the fts5 extension 8096** function. See the xSetAuxdata() method for details. 8097** 8098** If the bClear argument is non-zero, then the auxiliary data is cleared 8099** (set to NULL) before this function returns. In this case the xDelete, 8100** if any, is not invoked. 8101** 8102** 8103** xRowCount(pFts5, pnRow) 8104** 8105** This function is used to retrieve the total number of rows in the table. 8106** In other words, the same value that would be returned by: 8107** 8108** SELECT count(*) FROM ftstable; 8109** 8110** xPhraseFirst() 8111** This function is used, along with type Fts5PhraseIter and the xPhraseNext 8112** method, to iterate through all instances of a single query phrase within 8113** the current row. This is the same information as is accessible via the 8114** xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient 8115** to use, this API may be faster under some circumstances. To iterate 8116** through instances of phrase iPhrase, use the following code: 8117** 8118** Fts5PhraseIter iter; 8119** int iCol, iOff; 8120** for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff); 8121** iOff>=0; 8122** pApi->xPhraseNext(pFts, &iter, &iCol, &iOff) 8123** ){ 8124** // An instance of phrase iPhrase at offset iOff of column iCol 8125** } 8126** 8127** The Fts5PhraseIter structure is defined above. Applications should not 8128** modify this structure directly - it should only be used as shown above 8129** with the xPhraseFirst() and xPhraseNext() API methods. 8130** 8131** xPhraseNext() 8132** See xPhraseFirst above. 8133*/ 8134struct Fts5ExtensionApi { 8135 int iVersion; /* Currently always set to 1 */ 8136 8137 void *(*xUserData)(Fts5Context*); 8138 8139 int (*xColumnCount)(Fts5Context*); 8140 int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow); 8141 int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken); 8142 8143 int (*xTokenize)(Fts5Context*, 8144 const char *pText, int nText, /* Text to tokenize */ 8145 void *pCtx, /* Context passed to xToken() */ 8146 int (*xToken)(void*, int, const char*, int, int, int) /* Callback */ 8147 ); 8148 8149 int (*xPhraseCount)(Fts5Context*); 8150 int (*xPhraseSize)(Fts5Context*, int iPhrase); 8151 8152 int (*xInstCount)(Fts5Context*, int *pnInst); 8153 int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff); 8154 8155 sqlite3_int64 (*xRowid)(Fts5Context*); 8156 int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn); 8157 int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken); 8158 8159 int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData, 8160 int(*)(const Fts5ExtensionApi*,Fts5Context*,void*) 8161 ); 8162 int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*)); 8163 void *(*xGetAuxdata)(Fts5Context*, int bClear); 8164 8165 void (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*); 8166 void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff); 8167}; 8168 8169/* 8170** CUSTOM AUXILIARY FUNCTIONS 8171*************************************************************************/ 8172 8173/************************************************************************* 8174** CUSTOM TOKENIZERS 8175** 8176** Applications may also register custom tokenizer types. A tokenizer 8177** is registered by providing fts5 with a populated instance of the 8178** following structure. All structure methods must be defined, setting 8179** any member of the fts5_tokenizer struct to NULL leads to undefined 8180** behaviour. The structure methods are expected to function as follows: 8181** 8182** xCreate: 8183** This function is used to allocate and inititalize a tokenizer instance. 8184** A tokenizer instance is required to actually tokenize text. 8185** 8186** The first argument passed to this function is a copy of the (void*) 8187** pointer provided by the application when the fts5_tokenizer object 8188** was registered with FTS5 (the third argument to xCreateTokenizer()). 8189** The second and third arguments are an array of nul-terminated strings 8190** containing the tokenizer arguments, if any, specified following the 8191** tokenizer name as part of the CREATE VIRTUAL TABLE statement used 8192** to create the FTS5 table. 8193** 8194** The final argument is an output variable. If successful, (*ppOut) 8195** should be set to point to the new tokenizer handle and SQLITE_OK 8196** returned. If an error occurs, some value other than SQLITE_OK should 8197** be returned. In this case, fts5 assumes that the final value of *ppOut 8198** is undefined. 8199** 8200** xDelete: 8201** This function is invoked to delete a tokenizer handle previously 8202** allocated using xCreate(). Fts5 guarantees that this function will 8203** be invoked exactly once for each successful call to xCreate(). 8204** 8205** xTokenize: 8206** This function is expected to tokenize the nText byte string indicated 8207** by argument pText. pText may or may not be nul-terminated. The first 8208** argument passed to this function is a pointer to an Fts5Tokenizer object 8209** returned by an earlier call to xCreate(). 8210** 8211** The second argument indicates the reason that FTS5 is requesting 8212** tokenization of the supplied text. This is always one of the following 8213** four values: 8214** 8215** <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into 8216** or removed from the FTS table. The tokenizer is being invoked to 8217** determine the set of tokens to add to (or delete from) the 8218** FTS index. 8219** 8220** <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed 8221** against the FTS index. The tokenizer is being called to tokenize 8222** a bareword or quoted string specified as part of the query. 8223** 8224** <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as 8225** FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is 8226** followed by a "*" character, indicating that the last token 8227** returned by the tokenizer will be treated as a token prefix. 8228** 8229** <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to 8230** satisfy an fts5_api.xTokenize() request made by an auxiliary 8231** function. Or an fts5_api.xColumnSize() request made by the same 8232** on a columnsize=0 database. 8233** </ul> 8234** 8235** For each token in the input string, the supplied callback xToken() must 8236** be invoked. The first argument to it should be a copy of the pointer 8237** passed as the second argument to xTokenize(). The third and fourth 8238** arguments are a pointer to a buffer containing the token text, and the 8239** size of the token in bytes. The 4th and 5th arguments are the byte offsets 8240** of the first byte of and first byte immediately following the text from 8241** which the token is derived within the input. 8242** 8243** The second argument passed to the xToken() callback ("tflags") should 8244** normally be set to 0. The exception is if the tokenizer supports 8245** synonyms. In this case see the discussion below for details. 8246** 8247** FTS5 assumes the xToken() callback is invoked for each token in the 8248** order that they occur within the input text. 8249** 8250** If an xToken() callback returns any value other than SQLITE_OK, then 8251** the tokenization should be abandoned and the xTokenize() method should 8252** immediately return a copy of the xToken() return value. Or, if the 8253** input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally, 8254** if an error occurs with the xTokenize() implementation itself, it 8255** may abandon the tokenization and return any error code other than 8256** SQLITE_OK or SQLITE_DONE. 8257** 8258** SYNONYM SUPPORT 8259** 8260** Custom tokenizers may also support synonyms. Consider a case in which a 8261** user wishes to query for a phrase such as "first place". Using the 8262** built-in tokenizers, the FTS5 query 'first + place' will match instances 8263** of "first place" within the document set, but not alternative forms 8264** such as "1st place". In some applications, it would be better to match 8265** all instances of "first place" or "1st place" regardless of which form 8266** the user specified in the MATCH query text. 8267** 8268** There are several ways to approach this in FTS5: 8269** 8270** <ol><li> By mapping all synonyms to a single token. In this case, the 8271** In the above example, this means that the tokenizer returns the 8272** same token for inputs "first" and "1st". Say that token is in 8273** fact "first", so that when the user inserts the document "I won 8274** 1st place" entries are added to the index for tokens "i", "won", 8275** "first" and "place". If the user then queries for '1st + place', 8276** the tokenizer substitutes "first" for "1st" and the query works 8277** as expected. 8278** 8279** <li> By adding multiple synonyms for a single term to the FTS index. 8280** In this case, when tokenizing query text, the tokenizer may 8281** provide multiple synonyms for a single term within the document. 8282** FTS5 then queries the index for each synonym individually. For 8283** example, faced with the query: 8284** 8285** <codeblock> 8286** ... MATCH 'first place'</codeblock> 8287** 8288** the tokenizer offers both "1st" and "first" as synonyms for the 8289** first token in the MATCH query and FTS5 effectively runs a query 8290** similar to: 8291** 8292** <codeblock> 8293** ... MATCH '(first OR 1st) place'</codeblock> 8294** 8295** except that, for the purposes of auxiliary functions, the query 8296** still appears to contain just two phrases - "(first OR 1st)" 8297** being treated as a single phrase. 8298** 8299** <li> By adding multiple synonyms for a single term to the FTS index. 8300** Using this method, when tokenizing document text, the tokenizer 8301** provides multiple synonyms for each token. So that when a 8302** document such as "I won first place" is tokenized, entries are 8303** added to the FTS index for "i", "won", "first", "1st" and 8304** "place". 8305** 8306** This way, even if the tokenizer does not provide synonyms 8307** when tokenizing query text (it should not - to do would be 8308** inefficient), it doesn't matter if the user queries for 8309** 'first + place' or '1st + place', as there are entires in the 8310** FTS index corresponding to both forms of the first token. 8311** </ol> 8312** 8313** Whether it is parsing document or query text, any call to xToken that 8314** specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit 8315** is considered to supply a synonym for the previous token. For example, 8316** when parsing the document "I won first place", a tokenizer that supports 8317** synonyms would call xToken() 5 times, as follows: 8318** 8319** <codeblock> 8320** xToken(pCtx, 0, "i", 1, 0, 1); 8321** xToken(pCtx, 0, "won", 3, 2, 5); 8322** xToken(pCtx, 0, "first", 5, 6, 11); 8323** xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3, 6, 11); 8324** xToken(pCtx, 0, "place", 5, 12, 17); 8325**</codeblock> 8326** 8327** It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time 8328** xToken() is called. Multiple synonyms may be specified for a single token 8329** by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence. 8330** There is no limit to the number of synonyms that may be provided for a 8331** single token. 8332** 8333** In many cases, method (1) above is the best approach. It does not add 8334** extra data to the FTS index or require FTS5 to query for multiple terms, 8335** so it is efficient in terms of disk space and query speed. However, it 8336** does not support prefix queries very well. If, as suggested above, the 8337** token "first" is subsituted for "1st" by the tokenizer, then the query: 8338** 8339** <codeblock> 8340** ... MATCH '1s*'</codeblock> 8341** 8342** will not match documents that contain the token "1st" (as the tokenizer 8343** will probably not map "1s" to any prefix of "first"). 8344** 8345** For full prefix support, method (3) may be preferred. In this case, 8346** because the index contains entries for both "first" and "1st", prefix 8347** queries such as 'fi*' or '1s*' will match correctly. However, because 8348** extra entries are added to the FTS index, this method uses more space 8349** within the database. 8350** 8351** Method (2) offers a midpoint between (1) and (3). Using this method, 8352** a query such as '1s*' will match documents that contain the literal 8353** token "1st", but not "first" (assuming the tokenizer is not able to 8354** provide synonyms for prefixes). However, a non-prefix query like '1st' 8355** will match against "1st" and "first". This method does not require 8356** extra disk space, as no extra entries are added to the FTS index. 8357** On the other hand, it may require more CPU cycles to run MATCH queries, 8358** as separate queries of the FTS index are required for each synonym. 8359** 8360** When using methods (2) or (3), it is important that the tokenizer only 8361** provide synonyms when tokenizing document text (method (2)) or query 8362** text (method (3)), not both. Doing so will not cause any errors, but is 8363** inefficient. 8364*/ 8365typedef struct Fts5Tokenizer Fts5Tokenizer; 8366typedef struct fts5_tokenizer fts5_tokenizer; 8367struct fts5_tokenizer { 8368 int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut); 8369 void (*xDelete)(Fts5Tokenizer*); 8370 int (*xTokenize)(Fts5Tokenizer*, 8371 void *pCtx, 8372 int flags, /* Mask of FTS5_TOKENIZE_* flags */ 8373 const char *pText, int nText, 8374 int (*xToken)( 8375 void *pCtx, /* Copy of 2nd argument to xTokenize() */ 8376 int tflags, /* Mask of FTS5_TOKEN_* flags */ 8377 const char *pToken, /* Pointer to buffer containing token */ 8378 int nToken, /* Size of token in bytes */ 8379 int iStart, /* Byte offset of token within input text */ 8380 int iEnd /* Byte offset of end of token within input text */ 8381 ) 8382 ); 8383}; 8384 8385/* Flags that may be passed as the third argument to xTokenize() */ 8386#define FTS5_TOKENIZE_QUERY 0x0001 8387#define FTS5_TOKENIZE_PREFIX 0x0002 8388#define FTS5_TOKENIZE_DOCUMENT 0x0004 8389#define FTS5_TOKENIZE_AUX 0x0008 8390 8391/* Flags that may be passed by the tokenizer implementation back to FTS5 8392** as the third argument to the supplied xToken callback. */ 8393#define FTS5_TOKEN_COLOCATED 0x0001 /* Same position as prev. token */ 8394 8395/* 8396** END OF CUSTOM TOKENIZERS 8397*************************************************************************/ 8398 8399/************************************************************************* 8400** FTS5 EXTENSION REGISTRATION API 8401*/ 8402typedef struct fts5_api fts5_api; 8403struct fts5_api { 8404 int iVersion; /* Currently always set to 2 */ 8405 8406 /* Create a new tokenizer */ 8407 int (*xCreateTokenizer)( 8408 fts5_api *pApi, 8409 const char *zName, 8410 void *pContext, 8411 fts5_tokenizer *pTokenizer, 8412 void (*xDestroy)(void*) 8413 ); 8414 8415 /* Find an existing tokenizer */ 8416 int (*xFindTokenizer)( 8417 fts5_api *pApi, 8418 const char *zName, 8419 void **ppContext, 8420 fts5_tokenizer *pTokenizer 8421 ); 8422 8423 /* Create a new auxiliary function */ 8424 int (*xCreateFunction)( 8425 fts5_api *pApi, 8426 const char *zName, 8427 void *pContext, 8428 fts5_extension_function xFunction, 8429 void (*xDestroy)(void*) 8430 ); 8431}; 8432 8433/* 8434** END OF REGISTRATION API 8435*************************************************************************/ 8436 8437#ifdef __cplusplus 8438} /* end of the 'extern "C"' block */ 8439#endif 8440 8441#endif /* _FTS5_H */ 8442 8443 8444