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 "--VERS--" 115#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 116#define SQLITE_SOURCE_ID "--SOURCE-ID--" 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_EXTERN const char sqlite3_version[]; 149const char *sqlite3_libversion(void); 150const char *sqlite3_sourceid(void); 151int 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 176int sqlite3_compileoption_used(const char *zOptName); 177const char *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*/ 216int 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*/ 313int sqlite3_close(sqlite3*); 314int 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*/ 385int 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_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 482#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 483#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 484#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 485#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 486#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 487#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 488#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 489#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 490#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 491#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 492#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 493#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 494#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 495#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 496#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 497#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 498#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 499#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 500#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 501#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 502#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 503#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 504#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 505#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 506#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 507#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 508#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 509 510/* 511** CAPI3REF: Flags For File Open Operations 512** 513** These bit values are intended for use in the 514** 3rd parameter to the [sqlite3_open_v2()] interface and 515** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 516*/ 517#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 518#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 519#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 520#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 521#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 522#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 523#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 524#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 525#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 526#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 527#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 528#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 529#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 530#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 531#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 532#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 533#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 534#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 535#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 536#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 537 538/* Reserved: 0x00F00000 */ 539 540/* 541** CAPI3REF: Device Characteristics 542** 543** The xDeviceCharacteristics method of the [sqlite3_io_methods] 544** object returns an integer which is a vector of these 545** bit values expressing I/O characteristics of the mass storage 546** device that holds the file that the [sqlite3_io_methods] 547** refers to. 548** 549** The SQLITE_IOCAP_ATOMIC property means that all writes of 550** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 551** mean that writes of blocks that are nnn bytes in size and 552** are aligned to an address which is an integer multiple of 553** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 554** that when data is appended to a file, the data is appended 555** first then the size of the file is extended, never the other 556** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 557** information is written to disk in the same order as calls 558** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 559** after reboot following a crash or power loss, the only bytes in a 560** file that were written at the application level might have changed 561** and that adjacent bytes, even bytes within the same sector are 562** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 563** flag indicate that a file cannot be deleted when open. The 564** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 565** read-only media and cannot be changed even by processes with 566** elevated privileges. 567*/ 568#define SQLITE_IOCAP_ATOMIC 0x00000001 569#define SQLITE_IOCAP_ATOMIC512 0x00000002 570#define SQLITE_IOCAP_ATOMIC1K 0x00000004 571#define SQLITE_IOCAP_ATOMIC2K 0x00000008 572#define SQLITE_IOCAP_ATOMIC4K 0x00000010 573#define SQLITE_IOCAP_ATOMIC8K 0x00000020 574#define SQLITE_IOCAP_ATOMIC16K 0x00000040 575#define SQLITE_IOCAP_ATOMIC32K 0x00000080 576#define SQLITE_IOCAP_ATOMIC64K 0x00000100 577#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 578#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 579#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 580#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 581#define SQLITE_IOCAP_IMMUTABLE 0x00002000 582 583/* 584** CAPI3REF: File Locking Levels 585** 586** SQLite uses one of these integer values as the second 587** argument to calls it makes to the xLock() and xUnlock() methods 588** of an [sqlite3_io_methods] object. 589*/ 590#define SQLITE_LOCK_NONE 0 591#define SQLITE_LOCK_SHARED 1 592#define SQLITE_LOCK_RESERVED 2 593#define SQLITE_LOCK_PENDING 3 594#define SQLITE_LOCK_EXCLUSIVE 4 595 596/* 597** CAPI3REF: Synchronization Type Flags 598** 599** When SQLite invokes the xSync() method of an 600** [sqlite3_io_methods] object it uses a combination of 601** these integer values as the second argument. 602** 603** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 604** sync operation only needs to flush data to mass storage. Inode 605** information need not be flushed. If the lower four bits of the flag 606** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 607** If the lower four bits equal SQLITE_SYNC_FULL, that means 608** to use Mac OS X style fullsync instead of fsync(). 609** 610** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 611** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 612** settings. The [synchronous pragma] determines when calls to the 613** xSync VFS method occur and applies uniformly across all platforms. 614** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 615** energetic or rigorous or forceful the sync operations are and 616** only make a difference on Mac OSX for the default SQLite code. 617** (Third-party VFS implementations might also make the distinction 618** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 619** operating systems natively supported by SQLite, only Mac OSX 620** cares about the difference.) 621*/ 622#define SQLITE_SYNC_NORMAL 0x00002 623#define SQLITE_SYNC_FULL 0x00003 624#define SQLITE_SYNC_DATAONLY 0x00010 625 626/* 627** CAPI3REF: OS Interface Open File Handle 628** 629** An [sqlite3_file] object represents an open file in the 630** [sqlite3_vfs | OS interface layer]. Individual OS interface 631** implementations will 632** want to subclass this object by appending additional fields 633** for their own use. The pMethods entry is a pointer to an 634** [sqlite3_io_methods] object that defines methods for performing 635** I/O operations on the open file. 636*/ 637typedef struct sqlite3_file sqlite3_file; 638struct sqlite3_file { 639 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 640}; 641 642/* 643** CAPI3REF: OS Interface File Virtual Methods Object 644** 645** Every file opened by the [sqlite3_vfs.xOpen] method populates an 646** [sqlite3_file] object (or, more commonly, a subclass of the 647** [sqlite3_file] object) with a pointer to an instance of this object. 648** This object defines the methods used to perform various operations 649** against the open file represented by the [sqlite3_file] object. 650** 651** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 652** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 653** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 654** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 655** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 656** to NULL. 657** 658** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 659** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 660** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 661** flag may be ORed in to indicate that only the data of the file 662** and not its inode needs to be synced. 663** 664** The integer values to xLock() and xUnlock() are one of 665** <ul> 666** <li> [SQLITE_LOCK_NONE], 667** <li> [SQLITE_LOCK_SHARED], 668** <li> [SQLITE_LOCK_RESERVED], 669** <li> [SQLITE_LOCK_PENDING], or 670** <li> [SQLITE_LOCK_EXCLUSIVE]. 671** </ul> 672** xLock() increases the lock. xUnlock() decreases the lock. 673** The xCheckReservedLock() method checks whether any database connection, 674** either in this process or in some other process, is holding a RESERVED, 675** PENDING, or EXCLUSIVE lock on the file. It returns true 676** if such a lock exists and false otherwise. 677** 678** The xFileControl() method is a generic interface that allows custom 679** VFS implementations to directly control an open file using the 680** [sqlite3_file_control()] interface. The second "op" argument is an 681** integer opcode. The third argument is a generic pointer intended to 682** point to a structure that may contain arguments or space in which to 683** write return values. Potential uses for xFileControl() might be 684** functions to enable blocking locks with timeouts, to change the 685** locking strategy (for example to use dot-file locks), to inquire 686** about the status of a lock, or to break stale locks. The SQLite 687** core reserves all opcodes less than 100 for its own use. 688** A [file control opcodes | list of opcodes] less than 100 is available. 689** Applications that define a custom xFileControl method should use opcodes 690** greater than 100 to avoid conflicts. VFS implementations should 691** return [SQLITE_NOTFOUND] for file control opcodes that they do not 692** recognize. 693** 694** The xSectorSize() method returns the sector size of the 695** device that underlies the file. The sector size is the 696** minimum write that can be performed without disturbing 697** other bytes in the file. The xDeviceCharacteristics() 698** method returns a bit vector describing behaviors of the 699** underlying device: 700** 701** <ul> 702** <li> [SQLITE_IOCAP_ATOMIC] 703** <li> [SQLITE_IOCAP_ATOMIC512] 704** <li> [SQLITE_IOCAP_ATOMIC1K] 705** <li> [SQLITE_IOCAP_ATOMIC2K] 706** <li> [SQLITE_IOCAP_ATOMIC4K] 707** <li> [SQLITE_IOCAP_ATOMIC8K] 708** <li> [SQLITE_IOCAP_ATOMIC16K] 709** <li> [SQLITE_IOCAP_ATOMIC32K] 710** <li> [SQLITE_IOCAP_ATOMIC64K] 711** <li> [SQLITE_IOCAP_SAFE_APPEND] 712** <li> [SQLITE_IOCAP_SEQUENTIAL] 713** </ul> 714** 715** The SQLITE_IOCAP_ATOMIC property means that all writes of 716** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 717** mean that writes of blocks that are nnn bytes in size and 718** are aligned to an address which is an integer multiple of 719** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 720** that when data is appended to a file, the data is appended 721** first then the size of the file is extended, never the other 722** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 723** information is written to disk in the same order as calls 724** to xWrite(). 725** 726** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 727** in the unread portions of the buffer with zeros. A VFS that 728** fails to zero-fill short reads might seem to work. However, 729** failure to zero-fill short reads will eventually lead to 730** database corruption. 731*/ 732typedef struct sqlite3_io_methods sqlite3_io_methods; 733struct sqlite3_io_methods { 734 int iVersion; 735 int (*xClose)(sqlite3_file*); 736 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 737 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 738 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 739 int (*xSync)(sqlite3_file*, int flags); 740 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 741 int (*xLock)(sqlite3_file*, int); 742 int (*xUnlock)(sqlite3_file*, int); 743 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 744 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 745 int (*xSectorSize)(sqlite3_file*); 746 int (*xDeviceCharacteristics)(sqlite3_file*); 747 /* Methods above are valid for version 1 */ 748 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 749 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 750 void (*xShmBarrier)(sqlite3_file*); 751 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 752 /* Methods above are valid for version 2 */ 753 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 754 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 755 /* Methods above are valid for version 3 */ 756 /* Additional methods may be added in future releases */ 757}; 758 759/* 760** CAPI3REF: Standard File Control Opcodes 761** KEYWORDS: {file control opcodes} {file control opcode} 762** 763** These integer constants are opcodes for the xFileControl method 764** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 765** interface. 766** 767** <ul> 768** <li>[[SQLITE_FCNTL_LOCKSTATE]] 769** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 770** opcode causes the xFileControl method to write the current state of 771** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 772** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 773** into an integer that the pArg argument points to. This capability 774** is used during testing and is only available when the SQLITE_TEST 775** compile-time option is used. 776** 777** <li>[[SQLITE_FCNTL_SIZE_HINT]] 778** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 779** layer a hint of how large the database file will grow to be during the 780** current transaction. This hint is not guaranteed to be accurate but it 781** is often close. The underlying VFS might choose to preallocate database 782** file space based on this hint in order to help writes to the database 783** file run faster. 784** 785** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 786** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 787** extends and truncates the database file in chunks of a size specified 788** by the user. The fourth argument to [sqlite3_file_control()] should 789** point to an integer (type int) containing the new chunk-size to use 790** for the nominated database. Allocating database file space in large 791** chunks (say 1MB at a time), may reduce file-system fragmentation and 792** improve performance on some systems. 793** 794** <li>[[SQLITE_FCNTL_FILE_POINTER]] 795** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 796** to the [sqlite3_file] object associated with a particular database 797** connection. See the [sqlite3_file_control()] documentation for 798** additional information. 799** 800** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 801** No longer in use. 802** 803** <li>[[SQLITE_FCNTL_SYNC]] 804** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 805** sent to the VFS immediately before the xSync method is invoked on a 806** database file descriptor. Or, if the xSync method is not invoked 807** because the user has configured SQLite with 808** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 809** of the xSync method. In most cases, the pointer argument passed with 810** this file-control is NULL. However, if the database file is being synced 811** as part of a multi-database commit, the argument points to a nul-terminated 812** string containing the transactions master-journal file name. VFSes that 813** do not need this signal should silently ignore this opcode. Applications 814** should not call [sqlite3_file_control()] with this opcode as doing so may 815** disrupt the operation of the specialized VFSes that do require it. 816** 817** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 818** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 819** and sent to the VFS after a transaction has been committed immediately 820** but before the database is unlocked. VFSes that do not need this signal 821** should silently ignore this opcode. Applications should not call 822** [sqlite3_file_control()] with this opcode as doing so may disrupt the 823** operation of the specialized VFSes that do require it. 824** 825** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 826** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 827** retry counts and intervals for certain disk I/O operations for the 828** windows [VFS] in order to provide robustness in the presence of 829** anti-virus programs. By default, the windows VFS will retry file read, 830** file write, and file delete operations up to 10 times, with a delay 831** of 25 milliseconds before the first retry and with the delay increasing 832** by an additional 25 milliseconds with each subsequent retry. This 833** opcode allows these two values (10 retries and 25 milliseconds of delay) 834** to be adjusted. The values are changed for all database connections 835** within the same process. The argument is a pointer to an array of two 836** integers where the first integer i the new retry count and the second 837** integer is the delay. If either integer is negative, then the setting 838** is not changed but instead the prior value of that setting is written 839** into the array entry, allowing the current retry settings to be 840** interrogated. The zDbName parameter is ignored. 841** 842** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 843** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 844** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 845** write ahead log and shared memory files used for transaction control 846** are automatically deleted when the latest connection to the database 847** closes. Setting persistent WAL mode causes those files to persist after 848** close. Persisting the files is useful when other processes that do not 849** have write permission on the directory containing the database file want 850** to read the database file, as the WAL and shared memory files must exist 851** in order for the database to be readable. The fourth parameter to 852** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 853** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 854** WAL mode. If the integer is -1, then it is overwritten with the current 855** WAL persistence setting. 856** 857** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 858** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 859** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 860** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 861** xDeviceCharacteristics methods. The fourth parameter to 862** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 863** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 864** mode. If the integer is -1, then it is overwritten with the current 865** zero-damage mode setting. 866** 867** <li>[[SQLITE_FCNTL_OVERWRITE]] 868** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 869** a write transaction to indicate that, unless it is rolled back for some 870** reason, the entire database file will be overwritten by the current 871** transaction. This is used by VACUUM operations. 872** 873** <li>[[SQLITE_FCNTL_VFSNAME]] 874** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 875** all [VFSes] in the VFS stack. The names are of all VFS shims and the 876** final bottom-level VFS are written into memory obtained from 877** [sqlite3_malloc()] and the result is stored in the char* variable 878** that the fourth parameter of [sqlite3_file_control()] points to. 879** The caller is responsible for freeing the memory when done. As with 880** all file-control actions, there is no guarantee that this will actually 881** do anything. Callers should initialize the char* variable to a NULL 882** pointer in case this file-control is not implemented. This file-control 883** is intended for diagnostic use only. 884** 885** <li>[[SQLITE_FCNTL_VFS_POINTER]] 886** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 887** [VFSes] currently in use. ^(The argument X in 888** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 889** of type "[sqlite3_vfs] **". This opcodes will set *X 890** to a pointer to the top-level VFS.)^ 891** ^When there are multiple VFS shims in the stack, this opcode finds the 892** upper-most shim only. 893** 894** <li>[[SQLITE_FCNTL_PRAGMA]] 895** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 896** file control is sent to the open [sqlite3_file] object corresponding 897** to the database file to which the pragma statement refers. ^The argument 898** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 899** pointers to strings (char**) in which the second element of the array 900** is the name of the pragma and the third element is the argument to the 901** pragma or NULL if the pragma has no argument. ^The handler for an 902** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 903** of the char** argument point to a string obtained from [sqlite3_mprintf()] 904** or the equivalent and that string will become the result of the pragma or 905** the error message if the pragma fails. ^If the 906** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 907** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 908** file control returns [SQLITE_OK], then the parser assumes that the 909** VFS has handled the PRAGMA itself and the parser generates a no-op 910** prepared statement if result string is NULL, or that returns a copy 911** of the result string if the string is non-NULL. 912** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 913** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 914** that the VFS encountered an error while handling the [PRAGMA] and the 915** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 916** file control occurs at the beginning of pragma statement analysis and so 917** it is able to override built-in [PRAGMA] statements. 918** 919** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 920** ^The [SQLITE_FCNTL_BUSYHANDLER] 921** file-control may be invoked by SQLite on the database file handle 922** shortly after it is opened in order to provide a custom VFS with access 923** to the connections busy-handler callback. The argument is of type (void **) 924** - an array of two (void *) values. The first (void *) actually points 925** to a function of type (int (*)(void *)). In order to invoke the connections 926** busy-handler, this function should be invoked with the second (void *) in 927** the array as the only argument. If it returns non-zero, then the operation 928** should be retried. If it returns zero, the custom VFS should abandon the 929** current operation. 930** 931** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 932** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 933** to have SQLite generate a 934** temporary filename using the same algorithm that is followed to generate 935** temporary filenames for TEMP tables and other internal uses. The 936** argument should be a char** which will be filled with the filename 937** written into memory obtained from [sqlite3_malloc()]. The caller should 938** invoke [sqlite3_free()] on the result to avoid a memory leak. 939** 940** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 941** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 942** maximum number of bytes that will be used for memory-mapped I/O. 943** The argument is a pointer to a value of type sqlite3_int64 that 944** is an advisory maximum number of bytes in the file to memory map. The 945** pointer is overwritten with the old value. The limit is not changed if 946** the value originally pointed to is negative, and so the current limit 947** can be queried by passing in a pointer to a negative number. This 948** file-control is used internally to implement [PRAGMA mmap_size]. 949** 950** <li>[[SQLITE_FCNTL_TRACE]] 951** The [SQLITE_FCNTL_TRACE] file control provides advisory information 952** to the VFS about what the higher layers of the SQLite stack are doing. 953** This file control is used by some VFS activity tracing [shims]. 954** The argument is a zero-terminated string. Higher layers in the 955** SQLite stack may generate instances of this file control if 956** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 957** 958** <li>[[SQLITE_FCNTL_HAS_MOVED]] 959** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 960** pointer to an integer and it writes a boolean into that integer depending 961** on whether or not the file has been renamed, moved, or deleted since it 962** was first opened. 963** 964** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 965** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 966** opcode causes the xFileControl method to swap the file handle with the one 967** pointed to by the pArg argument. This capability is used during testing 968** and only needs to be supported when SQLITE_TEST is defined. 969** 970** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 971** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 972** be advantageous to block on the next WAL lock if the lock is not immediately 973** available. The WAL subsystem issues this signal during rare 974** circumstances in order to fix a problem with priority inversion. 975** Applications should <em>not</em> use this file-control. 976** 977** <li>[[SQLITE_FCNTL_ZIPVFS]] 978** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 979** VFS should return SQLITE_NOTFOUND for this opcode. 980** 981** <li>[[SQLITE_FCNTL_RBU]] 982** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 983** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 984** this opcode. 985** </ul> 986*/ 987#define SQLITE_FCNTL_LOCKSTATE 1 988#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 989#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 990#define SQLITE_FCNTL_LAST_ERRNO 4 991#define SQLITE_FCNTL_SIZE_HINT 5 992#define SQLITE_FCNTL_CHUNK_SIZE 6 993#define SQLITE_FCNTL_FILE_POINTER 7 994#define SQLITE_FCNTL_SYNC_OMITTED 8 995#define SQLITE_FCNTL_WIN32_AV_RETRY 9 996#define SQLITE_FCNTL_PERSIST_WAL 10 997#define SQLITE_FCNTL_OVERWRITE 11 998#define SQLITE_FCNTL_VFSNAME 12 999#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1000#define SQLITE_FCNTL_PRAGMA 14 1001#define SQLITE_FCNTL_BUSYHANDLER 15 1002#define SQLITE_FCNTL_TEMPFILENAME 16 1003#define SQLITE_FCNTL_MMAP_SIZE 18 1004#define SQLITE_FCNTL_TRACE 19 1005#define SQLITE_FCNTL_HAS_MOVED 20 1006#define SQLITE_FCNTL_SYNC 21 1007#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1008#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1009#define SQLITE_FCNTL_WAL_BLOCK 24 1010#define SQLITE_FCNTL_ZIPVFS 25 1011#define SQLITE_FCNTL_RBU 26 1012#define SQLITE_FCNTL_VFS_POINTER 27 1013 1014/* deprecated names */ 1015#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1016#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1017#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1018 1019 1020/* 1021** CAPI3REF: Mutex Handle 1022** 1023** The mutex module within SQLite defines [sqlite3_mutex] to be an 1024** abstract type for a mutex object. The SQLite core never looks 1025** at the internal representation of an [sqlite3_mutex]. It only 1026** deals with pointers to the [sqlite3_mutex] object. 1027** 1028** Mutexes are created using [sqlite3_mutex_alloc()]. 1029*/ 1030typedef struct sqlite3_mutex sqlite3_mutex; 1031 1032/* 1033** CAPI3REF: OS Interface Object 1034** 1035** An instance of the sqlite3_vfs object defines the interface between 1036** the SQLite core and the underlying operating system. The "vfs" 1037** in the name of the object stands for "virtual file system". See 1038** the [VFS | VFS documentation] for further information. 1039** 1040** The value of the iVersion field is initially 1 but may be larger in 1041** future versions of SQLite. Additional fields may be appended to this 1042** object when the iVersion value is increased. Note that the structure 1043** of the sqlite3_vfs object changes in the transaction between 1044** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1045** modified. 1046** 1047** The szOsFile field is the size of the subclassed [sqlite3_file] 1048** structure used by this VFS. mxPathname is the maximum length of 1049** a pathname in this VFS. 1050** 1051** Registered sqlite3_vfs objects are kept on a linked list formed by 1052** the pNext pointer. The [sqlite3_vfs_register()] 1053** and [sqlite3_vfs_unregister()] interfaces manage this list 1054** in a thread-safe way. The [sqlite3_vfs_find()] interface 1055** searches the list. Neither the application code nor the VFS 1056** implementation should use the pNext pointer. 1057** 1058** The pNext field is the only field in the sqlite3_vfs 1059** structure that SQLite will ever modify. SQLite will only access 1060** or modify this field while holding a particular static mutex. 1061** The application should never modify anything within the sqlite3_vfs 1062** object once the object has been registered. 1063** 1064** The zName field holds the name of the VFS module. The name must 1065** be unique across all VFS modules. 1066** 1067** [[sqlite3_vfs.xOpen]] 1068** ^SQLite guarantees that the zFilename parameter to xOpen 1069** is either a NULL pointer or string obtained 1070** from xFullPathname() with an optional suffix added. 1071** ^If a suffix is added to the zFilename parameter, it will 1072** consist of a single "-" character followed by no more than 1073** 11 alphanumeric and/or "-" characters. 1074** ^SQLite further guarantees that 1075** the string will be valid and unchanged until xClose() is 1076** called. Because of the previous sentence, 1077** the [sqlite3_file] can safely store a pointer to the 1078** filename if it needs to remember the filename for some reason. 1079** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1080** must invent its own temporary name for the file. ^Whenever the 1081** xFilename parameter is NULL it will also be the case that the 1082** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1083** 1084** The flags argument to xOpen() includes all bits set in 1085** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1086** or [sqlite3_open16()] is used, then flags includes at least 1087** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1088** If xOpen() opens a file read-only then it sets *pOutFlags to 1089** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1090** 1091** ^(SQLite will also add one of the following flags to the xOpen() 1092** call, depending on the object being opened: 1093** 1094** <ul> 1095** <li> [SQLITE_OPEN_MAIN_DB] 1096** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1097** <li> [SQLITE_OPEN_TEMP_DB] 1098** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1099** <li> [SQLITE_OPEN_TRANSIENT_DB] 1100** <li> [SQLITE_OPEN_SUBJOURNAL] 1101** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1102** <li> [SQLITE_OPEN_WAL] 1103** </ul>)^ 1104** 1105** The file I/O implementation can use the object type flags to 1106** change the way it deals with files. For example, an application 1107** that does not care about crash recovery or rollback might make 1108** the open of a journal file a no-op. Writes to this journal would 1109** also be no-ops, and any attempt to read the journal would return 1110** SQLITE_IOERR. Or the implementation might recognize that a database 1111** file will be doing page-aligned sector reads and writes in a random 1112** order and set up its I/O subsystem accordingly. 1113** 1114** SQLite might also add one of the following flags to the xOpen method: 1115** 1116** <ul> 1117** <li> [SQLITE_OPEN_DELETEONCLOSE] 1118** <li> [SQLITE_OPEN_EXCLUSIVE] 1119** </ul> 1120** 1121** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1122** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1123** will be set for TEMP databases and their journals, transient 1124** databases, and subjournals. 1125** 1126** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1127** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1128** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1129** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1130** SQLITE_OPEN_CREATE, is used to indicate that file should always 1131** be created, and that it is an error if it already exists. 1132** It is <i>not</i> used to indicate the file should be opened 1133** for exclusive access. 1134** 1135** ^At least szOsFile bytes of memory are allocated by SQLite 1136** to hold the [sqlite3_file] structure passed as the third 1137** argument to xOpen. The xOpen method does not have to 1138** allocate the structure; it should just fill it in. Note that 1139** the xOpen method must set the sqlite3_file.pMethods to either 1140** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1141** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1142** element will be valid after xOpen returns regardless of the success 1143** or failure of the xOpen call. 1144** 1145** [[sqlite3_vfs.xAccess]] 1146** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1147** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1148** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1149** to test whether a file is at least readable. The file can be a 1150** directory. 1151** 1152** ^SQLite will always allocate at least mxPathname+1 bytes for the 1153** output buffer xFullPathname. The exact size of the output buffer 1154** is also passed as a parameter to both methods. If the output buffer 1155** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1156** handled as a fatal error by SQLite, vfs implementations should endeavor 1157** to prevent this by setting mxPathname to a sufficiently large value. 1158** 1159** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1160** interfaces are not strictly a part of the filesystem, but they are 1161** included in the VFS structure for completeness. 1162** The xRandomness() function attempts to return nBytes bytes 1163** of good-quality randomness into zOut. The return value is 1164** the actual number of bytes of randomness obtained. 1165** The xSleep() method causes the calling thread to sleep for at 1166** least the number of microseconds given. ^The xCurrentTime() 1167** method returns a Julian Day Number for the current date and time as 1168** a floating point value. 1169** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1170** Day Number multiplied by 86400000 (the number of milliseconds in 1171** a 24-hour day). 1172** ^SQLite will use the xCurrentTimeInt64() method to get the current 1173** date and time if that method is available (if iVersion is 2 or 1174** greater and the function pointer is not NULL) and will fall back 1175** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1176** 1177** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1178** are not used by the SQLite core. These optional interfaces are provided 1179** by some VFSes to facilitate testing of the VFS code. By overriding 1180** system calls with functions under its control, a test program can 1181** simulate faults and error conditions that would otherwise be difficult 1182** or impossible to induce. The set of system calls that can be overridden 1183** varies from one VFS to another, and from one version of the same VFS to the 1184** next. Applications that use these interfaces must be prepared for any 1185** or all of these interfaces to be NULL or for their behavior to change 1186** from one release to the next. Applications must not attempt to access 1187** any of these methods if the iVersion of the VFS is less than 3. 1188*/ 1189typedef struct sqlite3_vfs sqlite3_vfs; 1190typedef void (*sqlite3_syscall_ptr)(void); 1191struct sqlite3_vfs { 1192 int iVersion; /* Structure version number (currently 3) */ 1193 int szOsFile; /* Size of subclassed sqlite3_file */ 1194 int mxPathname; /* Maximum file pathname length */ 1195 sqlite3_vfs *pNext; /* Next registered VFS */ 1196 const char *zName; /* Name of this virtual file system */ 1197 void *pAppData; /* Pointer to application-specific data */ 1198 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1199 int flags, int *pOutFlags); 1200 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1201 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1202 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1203 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1204 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1205 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1206 void (*xDlClose)(sqlite3_vfs*, void*); 1207 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1208 int (*xSleep)(sqlite3_vfs*, int microseconds); 1209 int (*xCurrentTime)(sqlite3_vfs*, double*); 1210 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1211 /* 1212 ** The methods above are in version 1 of the sqlite_vfs object 1213 ** definition. Those that follow are added in version 2 or later 1214 */ 1215 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1216 /* 1217 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1218 ** Those below are for version 3 and greater. 1219 */ 1220 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1221 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1222 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1223 /* 1224 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1225 ** New fields may be appended in figure versions. The iVersion 1226 ** value will increment whenever this happens. 1227 */ 1228}; 1229 1230/* 1231** CAPI3REF: Flags for the xAccess VFS method 1232** 1233** These integer constants can be used as the third parameter to 1234** the xAccess method of an [sqlite3_vfs] object. They determine 1235** what kind of permissions the xAccess method is looking for. 1236** With SQLITE_ACCESS_EXISTS, the xAccess method 1237** simply checks whether the file exists. 1238** With SQLITE_ACCESS_READWRITE, the xAccess method 1239** checks whether the named directory is both readable and writable 1240** (in other words, if files can be added, removed, and renamed within 1241** the directory). 1242** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1243** [temp_store_directory pragma], though this could change in a future 1244** release of SQLite. 1245** With SQLITE_ACCESS_READ, the xAccess method 1246** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1247** currently unused, though it might be used in a future release of 1248** SQLite. 1249*/ 1250#define SQLITE_ACCESS_EXISTS 0 1251#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1252#define SQLITE_ACCESS_READ 2 /* Unused */ 1253 1254/* 1255** CAPI3REF: Flags for the xShmLock VFS method 1256** 1257** These integer constants define the various locking operations 1258** allowed by the xShmLock method of [sqlite3_io_methods]. The 1259** following are the only legal combinations of flags to the 1260** xShmLock method: 1261** 1262** <ul> 1263** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1264** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1265** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1266** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1267** </ul> 1268** 1269** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1270** was given on the corresponding lock. 1271** 1272** The xShmLock method can transition between unlocked and SHARED or 1273** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1274** and EXCLUSIVE. 1275*/ 1276#define SQLITE_SHM_UNLOCK 1 1277#define SQLITE_SHM_LOCK 2 1278#define SQLITE_SHM_SHARED 4 1279#define SQLITE_SHM_EXCLUSIVE 8 1280 1281/* 1282** CAPI3REF: Maximum xShmLock index 1283** 1284** The xShmLock method on [sqlite3_io_methods] may use values 1285** between 0 and this upper bound as its "offset" argument. 1286** The SQLite core will never attempt to acquire or release a 1287** lock outside of this range 1288*/ 1289#define SQLITE_SHM_NLOCK 8 1290 1291 1292/* 1293** CAPI3REF: Initialize The SQLite Library 1294** 1295** ^The sqlite3_initialize() routine initializes the 1296** SQLite library. ^The sqlite3_shutdown() routine 1297** deallocates any resources that were allocated by sqlite3_initialize(). 1298** These routines are designed to aid in process initialization and 1299** shutdown on embedded systems. Workstation applications using 1300** SQLite normally do not need to invoke either of these routines. 1301** 1302** A call to sqlite3_initialize() is an "effective" call if it is 1303** the first time sqlite3_initialize() is invoked during the lifetime of 1304** the process, or if it is the first time sqlite3_initialize() is invoked 1305** following a call to sqlite3_shutdown(). ^(Only an effective call 1306** of sqlite3_initialize() does any initialization. All other calls 1307** are harmless no-ops.)^ 1308** 1309** A call to sqlite3_shutdown() is an "effective" call if it is the first 1310** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1311** an effective call to sqlite3_shutdown() does any deinitialization. 1312** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1313** 1314** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1315** is not. The sqlite3_shutdown() interface must only be called from a 1316** single thread. All open [database connections] must be closed and all 1317** other SQLite resources must be deallocated prior to invoking 1318** sqlite3_shutdown(). 1319** 1320** Among other things, ^sqlite3_initialize() will invoke 1321** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1322** will invoke sqlite3_os_end(). 1323** 1324** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1325** ^If for some reason, sqlite3_initialize() is unable to initialize 1326** the library (perhaps it is unable to allocate a needed resource such 1327** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1328** 1329** ^The sqlite3_initialize() routine is called internally by many other 1330** SQLite interfaces so that an application usually does not need to 1331** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1332** calls sqlite3_initialize() so the SQLite library will be automatically 1333** initialized when [sqlite3_open()] is called if it has not be initialized 1334** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1335** compile-time option, then the automatic calls to sqlite3_initialize() 1336** are omitted and the application must call sqlite3_initialize() directly 1337** prior to using any other SQLite interface. For maximum portability, 1338** it is recommended that applications always invoke sqlite3_initialize() 1339** directly prior to using any other SQLite interface. Future releases 1340** of SQLite may require this. In other words, the behavior exhibited 1341** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1342** default behavior in some future release of SQLite. 1343** 1344** The sqlite3_os_init() routine does operating-system specific 1345** initialization of the SQLite library. The sqlite3_os_end() 1346** routine undoes the effect of sqlite3_os_init(). Typical tasks 1347** performed by these routines include allocation or deallocation 1348** of static resources, initialization of global variables, 1349** setting up a default [sqlite3_vfs] module, or setting up 1350** a default configuration using [sqlite3_config()]. 1351** 1352** The application should never invoke either sqlite3_os_init() 1353** or sqlite3_os_end() directly. The application should only invoke 1354** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1355** interface is called automatically by sqlite3_initialize() and 1356** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1357** implementations for sqlite3_os_init() and sqlite3_os_end() 1358** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1359** When [custom builds | built for other platforms] 1360** (using the [SQLITE_OS_OTHER=1] compile-time 1361** option) the application must supply a suitable implementation for 1362** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1363** implementation of sqlite3_os_init() or sqlite3_os_end() 1364** must return [SQLITE_OK] on success and some other [error code] upon 1365** failure. 1366*/ 1367int sqlite3_initialize(void); 1368int sqlite3_shutdown(void); 1369int sqlite3_os_init(void); 1370int sqlite3_os_end(void); 1371 1372/* 1373** CAPI3REF: Configuring The SQLite Library 1374** 1375** The sqlite3_config() interface is used to make global configuration 1376** changes to SQLite in order to tune SQLite to the specific needs of 1377** the application. The default configuration is recommended for most 1378** applications and so this routine is usually not necessary. It is 1379** provided to support rare applications with unusual needs. 1380** 1381** <b>The sqlite3_config() interface is not threadsafe. The application 1382** must ensure that no other SQLite interfaces are invoked by other 1383** threads while sqlite3_config() is running.</b> 1384** 1385** The sqlite3_config() interface 1386** may only be invoked prior to library initialization using 1387** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1388** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1389** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1390** Note, however, that ^sqlite3_config() can be called as part of the 1391** implementation of an application-defined [sqlite3_os_init()]. 1392** 1393** The first argument to sqlite3_config() is an integer 1394** [configuration option] that determines 1395** what property of SQLite is to be configured. Subsequent arguments 1396** vary depending on the [configuration option] 1397** in the first argument. 1398** 1399** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1400** ^If the option is unknown or SQLite is unable to set the option 1401** then this routine returns a non-zero [error code]. 1402*/ 1403int sqlite3_config(int, ...); 1404 1405/* 1406** CAPI3REF: Configure database connections 1407** METHOD: sqlite3 1408** 1409** The sqlite3_db_config() interface is used to make configuration 1410** changes to a [database connection]. The interface is similar to 1411** [sqlite3_config()] except that the changes apply to a single 1412** [database connection] (specified in the first argument). 1413** 1414** The second argument to sqlite3_db_config(D,V,...) is the 1415** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1416** that indicates what aspect of the [database connection] is being configured. 1417** Subsequent arguments vary depending on the configuration verb. 1418** 1419** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1420** the call is considered successful. 1421*/ 1422int sqlite3_db_config(sqlite3*, int op, ...); 1423 1424/* 1425** CAPI3REF: Memory Allocation Routines 1426** 1427** An instance of this object defines the interface between SQLite 1428** and low-level memory allocation routines. 1429** 1430** This object is used in only one place in the SQLite interface. 1431** A pointer to an instance of this object is the argument to 1432** [sqlite3_config()] when the configuration option is 1433** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1434** By creating an instance of this object 1435** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1436** during configuration, an application can specify an alternative 1437** memory allocation subsystem for SQLite to use for all of its 1438** dynamic memory needs. 1439** 1440** Note that SQLite comes with several [built-in memory allocators] 1441** that are perfectly adequate for the overwhelming majority of applications 1442** and that this object is only useful to a tiny minority of applications 1443** with specialized memory allocation requirements. This object is 1444** also used during testing of SQLite in order to specify an alternative 1445** memory allocator that simulates memory out-of-memory conditions in 1446** order to verify that SQLite recovers gracefully from such 1447** conditions. 1448** 1449** The xMalloc, xRealloc, and xFree methods must work like the 1450** malloc(), realloc() and free() functions from the standard C library. 1451** ^SQLite guarantees that the second argument to 1452** xRealloc is always a value returned by a prior call to xRoundup. 1453** 1454** xSize should return the allocated size of a memory allocation 1455** previously obtained from xMalloc or xRealloc. The allocated size 1456** is always at least as big as the requested size but may be larger. 1457** 1458** The xRoundup method returns what would be the allocated size of 1459** a memory allocation given a particular requested size. Most memory 1460** allocators round up memory allocations at least to the next multiple 1461** of 8. Some allocators round up to a larger multiple or to a power of 2. 1462** Every memory allocation request coming in through [sqlite3_malloc()] 1463** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1464** that causes the corresponding memory allocation to fail. 1465** 1466** The xInit method initializes the memory allocator. For example, 1467** it might allocate any require mutexes or initialize internal data 1468** structures. The xShutdown method is invoked (indirectly) by 1469** [sqlite3_shutdown()] and should deallocate any resources acquired 1470** by xInit. The pAppData pointer is used as the only parameter to 1471** xInit and xShutdown. 1472** 1473** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1474** the xInit method, so the xInit method need not be threadsafe. The 1475** xShutdown method is only called from [sqlite3_shutdown()] so it does 1476** not need to be threadsafe either. For all other methods, SQLite 1477** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1478** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1479** it is by default) and so the methods are automatically serialized. 1480** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1481** methods must be threadsafe or else make their own arrangements for 1482** serialization. 1483** 1484** SQLite will never invoke xInit() more than once without an intervening 1485** call to xShutdown(). 1486*/ 1487typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1488struct sqlite3_mem_methods { 1489 void *(*xMalloc)(int); /* Memory allocation function */ 1490 void (*xFree)(void*); /* Free a prior allocation */ 1491 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1492 int (*xSize)(void*); /* Return the size of an allocation */ 1493 int (*xRoundup)(int); /* Round up request size to allocation size */ 1494 int (*xInit)(void*); /* Initialize the memory allocator */ 1495 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1496 void *pAppData; /* Argument to xInit() and xShutdown() */ 1497}; 1498 1499/* 1500** CAPI3REF: Configuration Options 1501** KEYWORDS: {configuration option} 1502** 1503** These constants are the available integer configuration options that 1504** can be passed as the first argument to the [sqlite3_config()] interface. 1505** 1506** New configuration options may be added in future releases of SQLite. 1507** Existing configuration options might be discontinued. Applications 1508** should check the return code from [sqlite3_config()] to make sure that 1509** the call worked. The [sqlite3_config()] interface will return a 1510** non-zero [error code] if a discontinued or unsupported configuration option 1511** is invoked. 1512** 1513** <dl> 1514** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1515** <dd>There are no arguments to this option. ^This option sets the 1516** [threading mode] to Single-thread. In other words, it disables 1517** all mutexing and puts SQLite into a mode where it can only be used 1518** by a single thread. ^If SQLite is compiled with 1519** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1520** it is not possible to change the [threading mode] from its default 1521** value of Single-thread and so [sqlite3_config()] will return 1522** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1523** configuration option.</dd> 1524** 1525** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1526** <dd>There are no arguments to this option. ^This option sets the 1527** [threading mode] to Multi-thread. In other words, it disables 1528** mutexing on [database connection] and [prepared statement] objects. 1529** The application is responsible for serializing access to 1530** [database connections] and [prepared statements]. But other mutexes 1531** are enabled so that SQLite will be safe to use in a multi-threaded 1532** environment as long as no two threads attempt to use the same 1533** [database connection] at the same time. ^If SQLite is compiled with 1534** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1535** it is not possible to set the Multi-thread [threading mode] and 1536** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1537** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1538** 1539** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1540** <dd>There are no arguments to this option. ^This option sets the 1541** [threading mode] to Serialized. In other words, this option enables 1542** all mutexes including the recursive 1543** mutexes on [database connection] and [prepared statement] objects. 1544** In this mode (which is the default when SQLite is compiled with 1545** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1546** to [database connections] and [prepared statements] so that the 1547** application is free to use the same [database connection] or the 1548** same [prepared statement] in different threads at the same time. 1549** ^If SQLite is compiled with 1550** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1551** it is not possible to set the Serialized [threading mode] and 1552** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1553** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1554** 1555** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1556** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1557** a pointer to an instance of the [sqlite3_mem_methods] structure. 1558** The argument specifies 1559** alternative low-level memory allocation routines to be used in place of 1560** the memory allocation routines built into SQLite.)^ ^SQLite makes 1561** its own private copy of the content of the [sqlite3_mem_methods] structure 1562** before the [sqlite3_config()] call returns.</dd> 1563** 1564** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1565** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1566** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1567** The [sqlite3_mem_methods] 1568** structure is filled with the currently defined memory allocation routines.)^ 1569** This option can be used to overload the default memory allocation 1570** routines with a wrapper that simulations memory allocation failure or 1571** tracks memory usage, for example. </dd> 1572** 1573** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1574** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1575** interpreted as a boolean, which enables or disables the collection of 1576** memory allocation statistics. ^(When memory allocation statistics are 1577** disabled, the following SQLite interfaces become non-operational: 1578** <ul> 1579** <li> [sqlite3_memory_used()] 1580** <li> [sqlite3_memory_highwater()] 1581** <li> [sqlite3_soft_heap_limit64()] 1582** <li> [sqlite3_status64()] 1583** </ul>)^ 1584** ^Memory allocation statistics are enabled by default unless SQLite is 1585** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1586** allocation statistics are disabled by default. 1587** </dd> 1588** 1589** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1590** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer 1591** that SQLite can use for scratch memory. ^(There are three arguments 1592** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte 1593** aligned memory buffer from which the scratch allocations will be 1594** drawn, the size of each scratch allocation (sz), 1595** and the maximum number of scratch allocations (N).)^ 1596** The first argument must be a pointer to an 8-byte aligned buffer 1597** of at least sz*N bytes of memory. 1598** ^SQLite will not use more than one scratch buffers per thread. 1599** ^SQLite will never request a scratch buffer that is more than 6 1600** times the database page size. 1601** ^If SQLite needs needs additional 1602** scratch memory beyond what is provided by this configuration option, then 1603** [sqlite3_malloc()] will be used to obtain the memory needed.<p> 1604** ^When the application provides any amount of scratch memory using 1605** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large 1606** [sqlite3_malloc|heap allocations]. 1607** This can help [Robson proof|prevent memory allocation failures] due to heap 1608** fragmentation in low-memory embedded systems. 1609** </dd> 1610** 1611** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1612** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1613** that SQLite can use for the database page cache with the default page 1614** cache implementation. 1615** This configuration option is a no-op if an application-define page 1616** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1617** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1618** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1619** and the number of cache lines (N). 1620** The sz argument should be the size of the largest database page 1621** (a power of two between 512 and 65536) plus some extra bytes for each 1622** page header. ^The number of extra bytes needed by the page header 1623** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1624** ^It is harmless, apart from the wasted memory, 1625** for the sz parameter to be larger than necessary. The pMem 1626** argument must be either a NULL pointer or a pointer to an 8-byte 1627** aligned block of memory of at least sz*N bytes, otherwise 1628** subsequent behavior is undefined. 1629** ^When pMem is not NULL, SQLite will strive to use the memory provided 1630** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1631** a page cache line is larger than sz bytes or if all of the pMem buffer 1632** is exhausted. 1633** ^If pMem is NULL and N is non-zero, then each database connection 1634** does an initial bulk allocation for page cache memory 1635** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1636** of -1024*N bytes if N is negative, . ^If additional 1637** page cache memory is needed beyond what is provided by the initial 1638** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1639** additional cache line. </dd> 1640** 1641** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1642** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1643** that SQLite will use for all of its dynamic memory allocation needs 1644** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and 1645** [SQLITE_CONFIG_PAGECACHE]. 1646** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1647** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1648** [SQLITE_ERROR] if invoked otherwise. 1649** ^There are three arguments to SQLITE_CONFIG_HEAP: 1650** An 8-byte aligned pointer to the memory, 1651** the number of bytes in the memory buffer, and the minimum allocation size. 1652** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1653** to using its default memory allocator (the system malloc() implementation), 1654** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1655** memory pointer is not NULL then the alternative memory 1656** allocator is engaged to handle all of SQLites memory allocation needs. 1657** The first pointer (the memory pointer) must be aligned to an 8-byte 1658** boundary or subsequent behavior of SQLite will be undefined. 1659** The minimum allocation size is capped at 2**12. Reasonable values 1660** for the minimum allocation size are 2**5 through 2**8.</dd> 1661** 1662** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1663** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1664** pointer to an instance of the [sqlite3_mutex_methods] structure. 1665** The argument specifies alternative low-level mutex routines to be used 1666** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1667** the content of the [sqlite3_mutex_methods] structure before the call to 1668** [sqlite3_config()] returns. ^If SQLite is compiled with 1669** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1670** the entire mutexing subsystem is omitted from the build and hence calls to 1671** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1672** return [SQLITE_ERROR].</dd> 1673** 1674** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1675** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1676** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1677** [sqlite3_mutex_methods] 1678** structure is filled with the currently defined mutex routines.)^ 1679** This option can be used to overload the default mutex allocation 1680** routines with a wrapper used to track mutex usage for performance 1681** profiling or testing, for example. ^If SQLite is compiled with 1682** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1683** the entire mutexing subsystem is omitted from the build and hence calls to 1684** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1685** return [SQLITE_ERROR].</dd> 1686** 1687** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1688** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1689** the default size of lookaside memory on each [database connection]. 1690** The first argument is the 1691** size of each lookaside buffer slot and the second is the number of 1692** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1693** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1694** option to [sqlite3_db_config()] can be used to change the lookaside 1695** configuration on individual connections.)^ </dd> 1696** 1697** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1698** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1699** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1700** the interface to a custom page cache implementation.)^ 1701** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1702** 1703** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1704** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1705** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1706** the current page cache implementation into that object.)^ </dd> 1707** 1708** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1709** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1710** global [error log]. 1711** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1712** function with a call signature of void(*)(void*,int,const char*), 1713** and a pointer to void. ^If the function pointer is not NULL, it is 1714** invoked by [sqlite3_log()] to process each logging event. ^If the 1715** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1716** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1717** passed through as the first parameter to the application-defined logger 1718** function whenever that function is invoked. ^The second parameter to 1719** the logger function is a copy of the first parameter to the corresponding 1720** [sqlite3_log()] call and is intended to be a [result code] or an 1721** [extended result code]. ^The third parameter passed to the logger is 1722** log message after formatting via [sqlite3_snprintf()]. 1723** The SQLite logging interface is not reentrant; the logger function 1724** supplied by the application must not invoke any SQLite interface. 1725** In a multi-threaded application, the application-defined logger 1726** function must be threadsafe. </dd> 1727** 1728** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1729** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1730** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1731** then URI handling is globally disabled.)^ ^If URI handling is globally 1732** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1733** [sqlite3_open16()] or 1734** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1735** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1736** connection is opened. ^If it is globally disabled, filenames are 1737** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1738** database connection is opened. ^(By default, URI handling is globally 1739** disabled. The default value may be changed by compiling with the 1740** [SQLITE_USE_URI] symbol defined.)^ 1741** 1742** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1743** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1744** argument which is interpreted as a boolean in order to enable or disable 1745** the use of covering indices for full table scans in the query optimizer. 1746** ^The default setting is determined 1747** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1748** if that compile-time option is omitted. 1749** The ability to disable the use of covering indices for full table scans 1750** is because some incorrectly coded legacy applications might malfunction 1751** when the optimization is enabled. Providing the ability to 1752** disable the optimization allows the older, buggy application code to work 1753** without change even with newer versions of SQLite. 1754** 1755** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1756** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1757** <dd> These options are obsolete and should not be used by new code. 1758** They are retained for backwards compatibility but are now no-ops. 1759** </dd> 1760** 1761** [[SQLITE_CONFIG_SQLLOG]] 1762** <dt>SQLITE_CONFIG_SQLLOG 1763** <dd>This option is only available if sqlite is compiled with the 1764** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1765** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1766** The second should be of type (void*). The callback is invoked by the library 1767** in three separate circumstances, identified by the value passed as the 1768** fourth parameter. If the fourth parameter is 0, then the database connection 1769** passed as the second argument has just been opened. The third argument 1770** points to a buffer containing the name of the main database file. If the 1771** fourth parameter is 1, then the SQL statement that the third parameter 1772** points to has just been executed. Or, if the fourth parameter is 2, then 1773** the connection being passed as the second parameter is being closed. The 1774** third parameter is passed NULL In this case. An example of using this 1775** configuration option can be seen in the "test_sqllog.c" source file in 1776** the canonical SQLite source tree.</dd> 1777** 1778** [[SQLITE_CONFIG_MMAP_SIZE]] 1779** <dt>SQLITE_CONFIG_MMAP_SIZE 1780** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1781** that are the default mmap size limit (the default setting for 1782** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1783** ^The default setting can be overridden by each database connection using 1784** either the [PRAGMA mmap_size] command, or by using the 1785** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1786** will be silently truncated if necessary so that it does not exceed the 1787** compile-time maximum mmap size set by the 1788** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1789** ^If either argument to this option is negative, then that argument is 1790** changed to its compile-time default. 1791** 1792** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1793** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1794** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1795** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1796** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1797** that specifies the maximum size of the created heap. 1798** 1799** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1800** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1801** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1802** is a pointer to an integer and writes into that integer the number of extra 1803** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1804** The amount of extra space required can change depending on the compiler, 1805** target platform, and SQLite version. 1806** 1807** [[SQLITE_CONFIG_PMASZ]] 1808** <dt>SQLITE_CONFIG_PMASZ 1809** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1810** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1811** sorter to that integer. The default minimum PMA Size is set by the 1812** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1813** to help with sort operations when multithreaded sorting 1814** is enabled (using the [PRAGMA threads] command) and the amount of content 1815** to be sorted exceeds the page size times the minimum of the 1816** [PRAGMA cache_size] setting and this value. 1817** </dl> 1818*/ 1819#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1820#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1821#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1822#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1823#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1824#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1825#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1826#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1827#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1828#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1829#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1830/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1831#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1832#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1833#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1834#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1835#define SQLITE_CONFIG_URI 17 /* int */ 1836#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1837#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1838#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1839#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1840#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1841#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1842#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1843#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1844 1845/* 1846** CAPI3REF: Database Connection Configuration Options 1847** 1848** These constants are the available integer configuration options that 1849** can be passed as the second argument to the [sqlite3_db_config()] interface. 1850** 1851** New configuration options may be added in future releases of SQLite. 1852** Existing configuration options might be discontinued. Applications 1853** should check the return code from [sqlite3_db_config()] to make sure that 1854** the call worked. ^The [sqlite3_db_config()] interface will return a 1855** non-zero [error code] if a discontinued or unsupported configuration option 1856** is invoked. 1857** 1858** <dl> 1859** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1860** <dd> ^This option takes three additional arguments that determine the 1861** [lookaside memory allocator] configuration for the [database connection]. 1862** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1863** pointer to a memory buffer to use for lookaside memory. 1864** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1865** may be NULL in which case SQLite will allocate the 1866** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1867** size of each lookaside buffer slot. ^The third argument is the number of 1868** slots. The size of the buffer in the first argument must be greater than 1869** or equal to the product of the second and third arguments. The buffer 1870** must be aligned to an 8-byte boundary. ^If the second argument to 1871** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1872** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1873** configuration for a database connection can only be changed when that 1874** connection is not currently using lookaside memory, or in other words 1875** when the "current value" returned by 1876** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1877** Any attempt to change the lookaside memory configuration when lookaside 1878** memory is in use leaves the configuration unchanged and returns 1879** [SQLITE_BUSY].)^</dd> 1880** 1881** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1882** <dd> ^This option is used to enable or disable the enforcement of 1883** [foreign key constraints]. There should be two additional arguments. 1884** The first argument is an integer which is 0 to disable FK enforcement, 1885** positive to enable FK enforcement or negative to leave FK enforcement 1886** unchanged. The second parameter is a pointer to an integer into which 1887** is written 0 or 1 to indicate whether FK enforcement is off or on 1888** following this call. The second parameter may be a NULL pointer, in 1889** which case the FK enforcement setting is not reported back. </dd> 1890** 1891** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1892** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1893** There should be two additional arguments. 1894** The first argument is an integer which is 0 to disable triggers, 1895** positive to enable triggers or negative to leave the setting unchanged. 1896** The second parameter is a pointer to an integer into which 1897** is written 0 or 1 to indicate whether triggers are disabled or enabled 1898** following this call. The second parameter may be a NULL pointer, in 1899** which case the trigger setting is not reported back. </dd> 1900** 1901** </dl> 1902*/ 1903#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1904#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1905#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1906 1907 1908/* 1909** CAPI3REF: Enable Or Disable Extended Result Codes 1910** METHOD: sqlite3 1911** 1912** ^The sqlite3_extended_result_codes() routine enables or disables the 1913** [extended result codes] feature of SQLite. ^The extended result 1914** codes are disabled by default for historical compatibility. 1915*/ 1916int sqlite3_extended_result_codes(sqlite3*, int onoff); 1917 1918/* 1919** CAPI3REF: Last Insert Rowid 1920** METHOD: sqlite3 1921** 1922** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 1923** has a unique 64-bit signed 1924** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1925** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1926** names are not also used by explicitly declared columns. ^If 1927** the table has a column of type [INTEGER PRIMARY KEY] then that column 1928** is another alias for the rowid. 1929** 1930** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the 1931** most recent successful [INSERT] into a rowid table or [virtual table] 1932** on database connection D. 1933** ^Inserts into [WITHOUT ROWID] tables are not recorded. 1934** ^If no successful [INSERT]s into rowid tables 1935** have ever occurred on the database connection D, 1936** then sqlite3_last_insert_rowid(D) returns zero. 1937** 1938** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1939** method, then this routine will return the [rowid] of the inserted 1940** row as long as the trigger or virtual table method is running. 1941** But once the trigger or virtual table method ends, the value returned 1942** by this routine reverts to what it was before the trigger or virtual 1943** table method began.)^ 1944** 1945** ^An [INSERT] that fails due to a constraint violation is not a 1946** successful [INSERT] and does not change the value returned by this 1947** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1948** and INSERT OR ABORT make no changes to the return value of this 1949** routine when their insertion fails. ^(When INSERT OR REPLACE 1950** encounters a constraint violation, it does not fail. The 1951** INSERT continues to completion after deleting rows that caused 1952** the constraint problem so INSERT OR REPLACE will always change 1953** the return value of this interface.)^ 1954** 1955** ^For the purposes of this routine, an [INSERT] is considered to 1956** be successful even if it is subsequently rolled back. 1957** 1958** This function is accessible to SQL statements via the 1959** [last_insert_rowid() SQL function]. 1960** 1961** If a separate thread performs a new [INSERT] on the same 1962** database connection while the [sqlite3_last_insert_rowid()] 1963** function is running and thus changes the last insert [rowid], 1964** then the value returned by [sqlite3_last_insert_rowid()] is 1965** unpredictable and might not equal either the old or the new 1966** last insert [rowid]. 1967*/ 1968sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1969 1970/* 1971** CAPI3REF: Count The Number Of Rows Modified 1972** METHOD: sqlite3 1973** 1974** ^This function returns the number of rows modified, inserted or 1975** deleted by the most recently completed INSERT, UPDATE or DELETE 1976** statement on the database connection specified by the only parameter. 1977** ^Executing any other type of SQL statement does not modify the value 1978** returned by this function. 1979** 1980** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 1981** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 1982** [foreign key actions] or [REPLACE] constraint resolution are not counted. 1983** 1984** Changes to a view that are intercepted by 1985** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 1986** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 1987** DELETE statement run on a view is always zero. Only changes made to real 1988** tables are counted. 1989** 1990** Things are more complicated if the sqlite3_changes() function is 1991** executed while a trigger program is running. This may happen if the 1992** program uses the [changes() SQL function], or if some other callback 1993** function invokes sqlite3_changes() directly. Essentially: 1994** 1995** <ul> 1996** <li> ^(Before entering a trigger program the value returned by 1997** sqlite3_changes() function is saved. After the trigger program 1998** has finished, the original value is restored.)^ 1999** 2000** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2001** statement sets the value returned by sqlite3_changes() 2002** upon completion as normal. Of course, this value will not include 2003** any changes performed by sub-triggers, as the sqlite3_changes() 2004** value will be saved and restored after each sub-trigger has run.)^ 2005** </ul> 2006** 2007** ^This means that if the changes() SQL function (or similar) is used 2008** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2009** returns the value as set when the calling statement began executing. 2010** ^If it is used by the second or subsequent such statement within a trigger 2011** program, the value returned reflects the number of rows modified by the 2012** previous INSERT, UPDATE or DELETE statement within the same trigger. 2013** 2014** See also the [sqlite3_total_changes()] interface, the 2015** [count_changes pragma], and the [changes() SQL function]. 2016** 2017** If a separate thread makes changes on the same database connection 2018** while [sqlite3_changes()] is running then the value returned 2019** is unpredictable and not meaningful. 2020*/ 2021int sqlite3_changes(sqlite3*); 2022 2023/* 2024** CAPI3REF: Total Number Of Rows Modified 2025** METHOD: sqlite3 2026** 2027** ^This function returns the total number of rows inserted, modified or 2028** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2029** since the database connection was opened, including those executed as 2030** part of trigger programs. ^Executing any other type of SQL statement 2031** does not affect the value returned by sqlite3_total_changes(). 2032** 2033** ^Changes made as part of [foreign key actions] are included in the 2034** count, but those made as part of REPLACE constraint resolution are 2035** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2036** are not counted. 2037** 2038** See also the [sqlite3_changes()] interface, the 2039** [count_changes pragma], and the [total_changes() SQL function]. 2040** 2041** If a separate thread makes changes on the same database connection 2042** while [sqlite3_total_changes()] is running then the value 2043** returned is unpredictable and not meaningful. 2044*/ 2045int sqlite3_total_changes(sqlite3*); 2046 2047/* 2048** CAPI3REF: Interrupt A Long-Running Query 2049** METHOD: sqlite3 2050** 2051** ^This function causes any pending database operation to abort and 2052** return at its earliest opportunity. This routine is typically 2053** called in response to a user action such as pressing "Cancel" 2054** or Ctrl-C where the user wants a long query operation to halt 2055** immediately. 2056** 2057** ^It is safe to call this routine from a thread different from the 2058** thread that is currently running the database operation. But it 2059** is not safe to call this routine with a [database connection] that 2060** is closed or might close before sqlite3_interrupt() returns. 2061** 2062** ^If an SQL operation is very nearly finished at the time when 2063** sqlite3_interrupt() is called, then it might not have an opportunity 2064** to be interrupted and might continue to completion. 2065** 2066** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2067** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2068** that is inside an explicit transaction, then the entire transaction 2069** will be rolled back automatically. 2070** 2071** ^The sqlite3_interrupt(D) call is in effect until all currently running 2072** SQL statements on [database connection] D complete. ^Any new SQL statements 2073** that are started after the sqlite3_interrupt() call and before the 2074** running statements reaches zero are interrupted as if they had been 2075** running prior to the sqlite3_interrupt() call. ^New SQL statements 2076** that are started after the running statement count reaches zero are 2077** not effected by the sqlite3_interrupt(). 2078** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2079** SQL statements is a no-op and has no effect on SQL statements 2080** that are started after the sqlite3_interrupt() call returns. 2081** 2082** If the database connection closes while [sqlite3_interrupt()] 2083** is running then bad things will likely happen. 2084*/ 2085void sqlite3_interrupt(sqlite3*); 2086 2087/* 2088** CAPI3REF: Determine If An SQL Statement Is Complete 2089** 2090** These routines are useful during command-line input to determine if the 2091** currently entered text seems to form a complete SQL statement or 2092** if additional input is needed before sending the text into 2093** SQLite for parsing. ^These routines return 1 if the input string 2094** appears to be a complete SQL statement. ^A statement is judged to be 2095** complete if it ends with a semicolon token and is not a prefix of a 2096** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2097** string literals or quoted identifier names or comments are not 2098** independent tokens (they are part of the token in which they are 2099** embedded) and thus do not count as a statement terminator. ^Whitespace 2100** and comments that follow the final semicolon are ignored. 2101** 2102** ^These routines return 0 if the statement is incomplete. ^If a 2103** memory allocation fails, then SQLITE_NOMEM is returned. 2104** 2105** ^These routines do not parse the SQL statements thus 2106** will not detect syntactically incorrect SQL. 2107** 2108** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2109** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2110** automatically by sqlite3_complete16(). If that initialization fails, 2111** then the return value from sqlite3_complete16() will be non-zero 2112** regardless of whether or not the input SQL is complete.)^ 2113** 2114** The input to [sqlite3_complete()] must be a zero-terminated 2115** UTF-8 string. 2116** 2117** The input to [sqlite3_complete16()] must be a zero-terminated 2118** UTF-16 string in native byte order. 2119*/ 2120int sqlite3_complete(const char *sql); 2121int sqlite3_complete16(const void *sql); 2122 2123/* 2124** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2125** KEYWORDS: {busy-handler callback} {busy handler} 2126** METHOD: sqlite3 2127** 2128** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2129** that might be invoked with argument P whenever 2130** an attempt is made to access a database table associated with 2131** [database connection] D when another thread 2132** or process has the table locked. 2133** The sqlite3_busy_handler() interface is used to implement 2134** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2135** 2136** ^If the busy callback is NULL, then [SQLITE_BUSY] 2137** is returned immediately upon encountering the lock. ^If the busy callback 2138** is not NULL, then the callback might be invoked with two arguments. 2139** 2140** ^The first argument to the busy handler is a copy of the void* pointer which 2141** is the third argument to sqlite3_busy_handler(). ^The second argument to 2142** the busy handler callback is the number of times that the busy handler has 2143** been invoked previously for the same locking event. ^If the 2144** busy callback returns 0, then no additional attempts are made to 2145** access the database and [SQLITE_BUSY] is returned 2146** to the application. 2147** ^If the callback returns non-zero, then another attempt 2148** is made to access the database and the cycle repeats. 2149** 2150** The presence of a busy handler does not guarantee that it will be invoked 2151** when there is lock contention. ^If SQLite determines that invoking the busy 2152** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2153** to the application instead of invoking the 2154** busy handler. 2155** Consider a scenario where one process is holding a read lock that 2156** it is trying to promote to a reserved lock and 2157** a second process is holding a reserved lock that it is trying 2158** to promote to an exclusive lock. The first process cannot proceed 2159** because it is blocked by the second and the second process cannot 2160** proceed because it is blocked by the first. If both processes 2161** invoke the busy handlers, neither will make any progress. Therefore, 2162** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2163** will induce the first process to release its read lock and allow 2164** the second process to proceed. 2165** 2166** ^The default busy callback is NULL. 2167** 2168** ^(There can only be a single busy handler defined for each 2169** [database connection]. Setting a new busy handler clears any 2170** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2171** or evaluating [PRAGMA busy_timeout=N] will change the 2172** busy handler and thus clear any previously set busy handler. 2173** 2174** The busy callback should not take any actions which modify the 2175** database connection that invoked the busy handler. In other words, 2176** the busy handler is not reentrant. Any such actions 2177** result in undefined behavior. 2178** 2179** A busy handler must not close the database connection 2180** or [prepared statement] that invoked the busy handler. 2181*/ 2182int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2183 2184/* 2185** CAPI3REF: Set A Busy Timeout 2186** METHOD: sqlite3 2187** 2188** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2189** for a specified amount of time when a table is locked. ^The handler 2190** will sleep multiple times until at least "ms" milliseconds of sleeping 2191** have accumulated. ^After at least "ms" milliseconds of sleeping, 2192** the handler returns 0 which causes [sqlite3_step()] to return 2193** [SQLITE_BUSY]. 2194** 2195** ^Calling this routine with an argument less than or equal to zero 2196** turns off all busy handlers. 2197** 2198** ^(There can only be a single busy handler for a particular 2199** [database connection] at any given moment. If another busy handler 2200** was defined (using [sqlite3_busy_handler()]) prior to calling 2201** this routine, that other busy handler is cleared.)^ 2202** 2203** See also: [PRAGMA busy_timeout] 2204*/ 2205int sqlite3_busy_timeout(sqlite3*, int ms); 2206 2207/* 2208** CAPI3REF: Convenience Routines For Running Queries 2209** METHOD: sqlite3 2210** 2211** This is a legacy interface that is preserved for backwards compatibility. 2212** Use of this interface is not recommended. 2213** 2214** Definition: A <b>result table</b> is memory data structure created by the 2215** [sqlite3_get_table()] interface. A result table records the 2216** complete query results from one or more queries. 2217** 2218** The table conceptually has a number of rows and columns. But 2219** these numbers are not part of the result table itself. These 2220** numbers are obtained separately. Let N be the number of rows 2221** and M be the number of columns. 2222** 2223** A result table is an array of pointers to zero-terminated UTF-8 strings. 2224** There are (N+1)*M elements in the array. The first M pointers point 2225** to zero-terminated strings that contain the names of the columns. 2226** The remaining entries all point to query results. NULL values result 2227** in NULL pointers. All other values are in their UTF-8 zero-terminated 2228** string representation as returned by [sqlite3_column_text()]. 2229** 2230** A result table might consist of one or more memory allocations. 2231** It is not safe to pass a result table directly to [sqlite3_free()]. 2232** A result table should be deallocated using [sqlite3_free_table()]. 2233** 2234** ^(As an example of the result table format, suppose a query result 2235** is as follows: 2236** 2237** <blockquote><pre> 2238** Name | Age 2239** ----------------------- 2240** Alice | 43 2241** Bob | 28 2242** Cindy | 21 2243** </pre></blockquote> 2244** 2245** There are two column (M==2) and three rows (N==3). Thus the 2246** result table has 8 entries. Suppose the result table is stored 2247** in an array names azResult. Then azResult holds this content: 2248** 2249** <blockquote><pre> 2250** azResult[0] = "Name"; 2251** azResult[1] = "Age"; 2252** azResult[2] = "Alice"; 2253** azResult[3] = "43"; 2254** azResult[4] = "Bob"; 2255** azResult[5] = "28"; 2256** azResult[6] = "Cindy"; 2257** azResult[7] = "21"; 2258** </pre></blockquote>)^ 2259** 2260** ^The sqlite3_get_table() function evaluates one or more 2261** semicolon-separated SQL statements in the zero-terminated UTF-8 2262** string of its 2nd parameter and returns a result table to the 2263** pointer given in its 3rd parameter. 2264** 2265** After the application has finished with the result from sqlite3_get_table(), 2266** it must pass the result table pointer to sqlite3_free_table() in order to 2267** release the memory that was malloced. Because of the way the 2268** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2269** function must not try to call [sqlite3_free()] directly. Only 2270** [sqlite3_free_table()] is able to release the memory properly and safely. 2271** 2272** The sqlite3_get_table() interface is implemented as a wrapper around 2273** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2274** to any internal data structures of SQLite. It uses only the public 2275** interface defined here. As a consequence, errors that occur in the 2276** wrapper layer outside of the internal [sqlite3_exec()] call are not 2277** reflected in subsequent calls to [sqlite3_errcode()] or 2278** [sqlite3_errmsg()]. 2279*/ 2280int sqlite3_get_table( 2281 sqlite3 *db, /* An open database */ 2282 const char *zSql, /* SQL to be evaluated */ 2283 char ***pazResult, /* Results of the query */ 2284 int *pnRow, /* Number of result rows written here */ 2285 int *pnColumn, /* Number of result columns written here */ 2286 char **pzErrmsg /* Error msg written here */ 2287); 2288void sqlite3_free_table(char **result); 2289 2290/* 2291** CAPI3REF: Formatted String Printing Functions 2292** 2293** These routines are work-alikes of the "printf()" family of functions 2294** from the standard C library. 2295** These routines understand most of the common K&R formatting options, 2296** plus some additional non-standard formats, detailed below. 2297** Note that some of the more obscure formatting options from recent 2298** C-library standards are omitted from this implementation. 2299** 2300** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2301** results into memory obtained from [sqlite3_malloc()]. 2302** The strings returned by these two routines should be 2303** released by [sqlite3_free()]. ^Both routines return a 2304** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2305** memory to hold the resulting string. 2306** 2307** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2308** the standard C library. The result is written into the 2309** buffer supplied as the second parameter whose size is given by 2310** the first parameter. Note that the order of the 2311** first two parameters is reversed from snprintf().)^ This is an 2312** historical accident that cannot be fixed without breaking 2313** backwards compatibility. ^(Note also that sqlite3_snprintf() 2314** returns a pointer to its buffer instead of the number of 2315** characters actually written into the buffer.)^ We admit that 2316** the number of characters written would be a more useful return 2317** value but we cannot change the implementation of sqlite3_snprintf() 2318** now without breaking compatibility. 2319** 2320** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2321** guarantees that the buffer is always zero-terminated. ^The first 2322** parameter "n" is the total size of the buffer, including space for 2323** the zero terminator. So the longest string that can be completely 2324** written will be n-1 characters. 2325** 2326** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2327** 2328** These routines all implement some additional formatting 2329** options that are useful for constructing SQL statements. 2330** All of the usual printf() formatting options apply. In addition, there 2331** is are "%q", "%Q", "%w" and "%z" options. 2332** 2333** ^(The %q option works like %s in that it substitutes a nul-terminated 2334** string from the argument list. But %q also doubles every '\'' character. 2335** %q is designed for use inside a string literal.)^ By doubling each '\'' 2336** character it escapes that character and allows it to be inserted into 2337** the string. 2338** 2339** For example, assume the string variable zText contains text as follows: 2340** 2341** <blockquote><pre> 2342** char *zText = "It's a happy day!"; 2343** </pre></blockquote> 2344** 2345** One can use this text in an SQL statement as follows: 2346** 2347** <blockquote><pre> 2348** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2349** sqlite3_exec(db, zSQL, 0, 0, 0); 2350** sqlite3_free(zSQL); 2351** </pre></blockquote> 2352** 2353** Because the %q format string is used, the '\'' character in zText 2354** is escaped and the SQL generated is as follows: 2355** 2356** <blockquote><pre> 2357** INSERT INTO table1 VALUES('It''s a happy day!') 2358** </pre></blockquote> 2359** 2360** This is correct. Had we used %s instead of %q, the generated SQL 2361** would have looked like this: 2362** 2363** <blockquote><pre> 2364** INSERT INTO table1 VALUES('It's a happy day!'); 2365** </pre></blockquote> 2366** 2367** This second example is an SQL syntax error. As a general rule you should 2368** always use %q instead of %s when inserting text into a string literal. 2369** 2370** ^(The %Q option works like %q except it also adds single quotes around 2371** the outside of the total string. Additionally, if the parameter in the 2372** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2373** single quotes).)^ So, for example, one could say: 2374** 2375** <blockquote><pre> 2376** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2377** sqlite3_exec(db, zSQL, 0, 0, 0); 2378** sqlite3_free(zSQL); 2379** </pre></blockquote> 2380** 2381** The code above will render a correct SQL statement in the zSQL 2382** variable even if the zText variable is a NULL pointer. 2383** 2384** ^(The "%w" formatting option is like "%q" except that it expects to 2385** be contained within double-quotes instead of single quotes, and it 2386** escapes the double-quote character instead of the single-quote 2387** character.)^ The "%w" formatting option is intended for safely inserting 2388** table and column names into a constructed SQL statement. 2389** 2390** ^(The "%z" formatting option works like "%s" but with the 2391** addition that after the string has been read and copied into 2392** the result, [sqlite3_free()] is called on the input string.)^ 2393*/ 2394char *sqlite3_mprintf(const char*,...); 2395char *sqlite3_vmprintf(const char*, va_list); 2396char *sqlite3_snprintf(int,char*,const char*, ...); 2397char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2398 2399/* 2400** CAPI3REF: Memory Allocation Subsystem 2401** 2402** The SQLite core uses these three routines for all of its own 2403** internal memory allocation needs. "Core" in the previous sentence 2404** does not include operating-system specific VFS implementation. The 2405** Windows VFS uses native malloc() and free() for some operations. 2406** 2407** ^The sqlite3_malloc() routine returns a pointer to a block 2408** of memory at least N bytes in length, where N is the parameter. 2409** ^If sqlite3_malloc() is unable to obtain sufficient free 2410** memory, it returns a NULL pointer. ^If the parameter N to 2411** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2412** a NULL pointer. 2413** 2414** ^The sqlite3_malloc64(N) routine works just like 2415** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2416** of a signed 32-bit integer. 2417** 2418** ^Calling sqlite3_free() with a pointer previously returned 2419** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2420** that it might be reused. ^The sqlite3_free() routine is 2421** a no-op if is called with a NULL pointer. Passing a NULL pointer 2422** to sqlite3_free() is harmless. After being freed, memory 2423** should neither be read nor written. Even reading previously freed 2424** memory might result in a segmentation fault or other severe error. 2425** Memory corruption, a segmentation fault, or other severe error 2426** might result if sqlite3_free() is called with a non-NULL pointer that 2427** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2428** 2429** ^The sqlite3_realloc(X,N) interface attempts to resize a 2430** prior memory allocation X to be at least N bytes. 2431** ^If the X parameter to sqlite3_realloc(X,N) 2432** is a NULL pointer then its behavior is identical to calling 2433** sqlite3_malloc(N). 2434** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2435** negative then the behavior is exactly the same as calling 2436** sqlite3_free(X). 2437** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2438** of at least N bytes in size or NULL if insufficient memory is available. 2439** ^If M is the size of the prior allocation, then min(N,M) bytes 2440** of the prior allocation are copied into the beginning of buffer returned 2441** by sqlite3_realloc(X,N) and the prior allocation is freed. 2442** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2443** prior allocation is not freed. 2444** 2445** ^The sqlite3_realloc64(X,N) interfaces works the same as 2446** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2447** of a 32-bit signed integer. 2448** 2449** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2450** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2451** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2452** ^The value returned by sqlite3_msize(X) might be larger than the number 2453** of bytes requested when X was allocated. ^If X is a NULL pointer then 2454** sqlite3_msize(X) returns zero. If X points to something that is not 2455** the beginning of memory allocation, or if it points to a formerly 2456** valid memory allocation that has now been freed, then the behavior 2457** of sqlite3_msize(X) is undefined and possibly harmful. 2458** 2459** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2460** sqlite3_malloc64(), and sqlite3_realloc64() 2461** is always aligned to at least an 8 byte boundary, or to a 2462** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2463** option is used. 2464** 2465** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2466** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2467** implementation of these routines to be omitted. That capability 2468** is no longer provided. Only built-in memory allocators can be used. 2469** 2470** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2471** the system malloc() and free() directly when converting 2472** filenames between the UTF-8 encoding used by SQLite 2473** and whatever filename encoding is used by the particular Windows 2474** installation. Memory allocation errors were detected, but 2475** they were reported back as [SQLITE_CANTOPEN] or 2476** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2477** 2478** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2479** must be either NULL or else pointers obtained from a prior 2480** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2481** not yet been released. 2482** 2483** The application must not read or write any part of 2484** a block of memory after it has been released using 2485** [sqlite3_free()] or [sqlite3_realloc()]. 2486*/ 2487void *sqlite3_malloc(int); 2488void *sqlite3_malloc64(sqlite3_uint64); 2489void *sqlite3_realloc(void*, int); 2490void *sqlite3_realloc64(void*, sqlite3_uint64); 2491void sqlite3_free(void*); 2492sqlite3_uint64 sqlite3_msize(void*); 2493 2494/* 2495** CAPI3REF: Memory Allocator Statistics 2496** 2497** SQLite provides these two interfaces for reporting on the status 2498** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2499** routines, which form the built-in memory allocation subsystem. 2500** 2501** ^The [sqlite3_memory_used()] routine returns the number of bytes 2502** of memory currently outstanding (malloced but not freed). 2503** ^The [sqlite3_memory_highwater()] routine returns the maximum 2504** value of [sqlite3_memory_used()] since the high-water mark 2505** was last reset. ^The values returned by [sqlite3_memory_used()] and 2506** [sqlite3_memory_highwater()] include any overhead 2507** added by SQLite in its implementation of [sqlite3_malloc()], 2508** but not overhead added by the any underlying system library 2509** routines that [sqlite3_malloc()] may call. 2510** 2511** ^The memory high-water mark is reset to the current value of 2512** [sqlite3_memory_used()] if and only if the parameter to 2513** [sqlite3_memory_highwater()] is true. ^The value returned 2514** by [sqlite3_memory_highwater(1)] is the high-water mark 2515** prior to the reset. 2516*/ 2517sqlite3_int64 sqlite3_memory_used(void); 2518sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2519 2520/* 2521** CAPI3REF: Pseudo-Random Number Generator 2522** 2523** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2524** select random [ROWID | ROWIDs] when inserting new records into a table that 2525** already uses the largest possible [ROWID]. The PRNG is also used for 2526** the build-in random() and randomblob() SQL functions. This interface allows 2527** applications to access the same PRNG for other purposes. 2528** 2529** ^A call to this routine stores N bytes of randomness into buffer P. 2530** ^The P parameter can be a NULL pointer. 2531** 2532** ^If this routine has not been previously called or if the previous 2533** call had N less than one or a NULL pointer for P, then the PRNG is 2534** seeded using randomness obtained from the xRandomness method of 2535** the default [sqlite3_vfs] object. 2536** ^If the previous call to this routine had an N of 1 or more and a 2537** non-NULL P then the pseudo-randomness is generated 2538** internally and without recourse to the [sqlite3_vfs] xRandomness 2539** method. 2540*/ 2541void sqlite3_randomness(int N, void *P); 2542 2543/* 2544** CAPI3REF: Compile-Time Authorization Callbacks 2545** METHOD: sqlite3 2546** 2547** ^This routine registers an authorizer callback with a particular 2548** [database connection], supplied in the first argument. 2549** ^The authorizer callback is invoked as SQL statements are being compiled 2550** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2551** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2552** points during the compilation process, as logic is being created 2553** to perform various actions, the authorizer callback is invoked to 2554** see if those actions are allowed. ^The authorizer callback should 2555** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2556** specific action but allow the SQL statement to continue to be 2557** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2558** rejected with an error. ^If the authorizer callback returns 2559** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2560** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2561** the authorizer will fail with an error message. 2562** 2563** When the callback returns [SQLITE_OK], that means the operation 2564** requested is ok. ^When the callback returns [SQLITE_DENY], the 2565** [sqlite3_prepare_v2()] or equivalent call that triggered the 2566** authorizer will fail with an error message explaining that 2567** access is denied. 2568** 2569** ^The first parameter to the authorizer callback is a copy of the third 2570** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2571** to the callback is an integer [SQLITE_COPY | action code] that specifies 2572** the particular action to be authorized. ^The third through sixth parameters 2573** to the callback are zero-terminated strings that contain additional 2574** details about the action to be authorized. 2575** 2576** ^If the action code is [SQLITE_READ] 2577** and the callback returns [SQLITE_IGNORE] then the 2578** [prepared statement] statement is constructed to substitute 2579** a NULL value in place of the table column that would have 2580** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2581** return can be used to deny an untrusted user access to individual 2582** columns of a table. 2583** ^If the action code is [SQLITE_DELETE] and the callback returns 2584** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2585** [truncate optimization] is disabled and all rows are deleted individually. 2586** 2587** An authorizer is used when [sqlite3_prepare | preparing] 2588** SQL statements from an untrusted source, to ensure that the SQL statements 2589** do not try to access data they are not allowed to see, or that they do not 2590** try to execute malicious statements that damage the database. For 2591** example, an application may allow a user to enter arbitrary 2592** SQL queries for evaluation by a database. But the application does 2593** not want the user to be able to make arbitrary changes to the 2594** database. An authorizer could then be put in place while the 2595** user-entered SQL is being [sqlite3_prepare | prepared] that 2596** disallows everything except [SELECT] statements. 2597** 2598** Applications that need to process SQL from untrusted sources 2599** might also consider lowering resource limits using [sqlite3_limit()] 2600** and limiting database size using the [max_page_count] [PRAGMA] 2601** in addition to using an authorizer. 2602** 2603** ^(Only a single authorizer can be in place on a database connection 2604** at a time. Each call to sqlite3_set_authorizer overrides the 2605** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2606** The authorizer is disabled by default. 2607** 2608** The authorizer callback must not do anything that will modify 2609** the database connection that invoked the authorizer callback. 2610** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2611** database connections for the meaning of "modify" in this paragraph. 2612** 2613** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2614** statement might be re-prepared during [sqlite3_step()] due to a 2615** schema change. Hence, the application should ensure that the 2616** correct authorizer callback remains in place during the [sqlite3_step()]. 2617** 2618** ^Note that the authorizer callback is invoked only during 2619** [sqlite3_prepare()] or its variants. Authorization is not 2620** performed during statement evaluation in [sqlite3_step()], unless 2621** as stated in the previous paragraph, sqlite3_step() invokes 2622** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2623*/ 2624int sqlite3_set_authorizer( 2625 sqlite3*, 2626 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2627 void *pUserData 2628); 2629 2630/* 2631** CAPI3REF: Authorizer Return Codes 2632** 2633** The [sqlite3_set_authorizer | authorizer callback function] must 2634** return either [SQLITE_OK] or one of these two constants in order 2635** to signal SQLite whether or not the action is permitted. See the 2636** [sqlite3_set_authorizer | authorizer documentation] for additional 2637** information. 2638** 2639** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2640** returned from the [sqlite3_vtab_on_conflict()] interface. 2641*/ 2642#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2643#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2644 2645/* 2646** CAPI3REF: Authorizer Action Codes 2647** 2648** The [sqlite3_set_authorizer()] interface registers a callback function 2649** that is invoked to authorize certain SQL statement actions. The 2650** second parameter to the callback is an integer code that specifies 2651** what action is being authorized. These are the integer action codes that 2652** the authorizer callback may be passed. 2653** 2654** These action code values signify what kind of operation is to be 2655** authorized. The 3rd and 4th parameters to the authorization 2656** callback function will be parameters or NULL depending on which of these 2657** codes is used as the second parameter. ^(The 5th parameter to the 2658** authorizer callback is the name of the database ("main", "temp", 2659** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2660** is the name of the inner-most trigger or view that is responsible for 2661** the access attempt or NULL if this access attempt is directly from 2662** top-level SQL code. 2663*/ 2664/******************************************* 3rd ************ 4th ***********/ 2665#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2666#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2667#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2668#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2669#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2670#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2671#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2672#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2673#define SQLITE_DELETE 9 /* Table Name NULL */ 2674#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2675#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2676#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2677#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2678#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2679#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2680#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2681#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2682#define SQLITE_INSERT 18 /* Table Name NULL */ 2683#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2684#define SQLITE_READ 20 /* Table Name Column Name */ 2685#define SQLITE_SELECT 21 /* NULL NULL */ 2686#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2687#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2688#define SQLITE_ATTACH 24 /* Filename NULL */ 2689#define SQLITE_DETACH 25 /* Database Name NULL */ 2690#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2691#define SQLITE_REINDEX 27 /* Index Name NULL */ 2692#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2693#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2694#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2695#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2696#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2697#define SQLITE_COPY 0 /* No longer used */ 2698#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2699 2700/* 2701** CAPI3REF: Tracing And Profiling Functions 2702** METHOD: sqlite3 2703** 2704** These routines register callback functions that can be used for 2705** tracing and profiling the execution of SQL statements. 2706** 2707** ^The callback function registered by sqlite3_trace() is invoked at 2708** various times when an SQL statement is being run by [sqlite3_step()]. 2709** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2710** SQL statement text as the statement first begins executing. 2711** ^(Additional sqlite3_trace() callbacks might occur 2712** as each triggered subprogram is entered. The callbacks for triggers 2713** contain a UTF-8 SQL comment that identifies the trigger.)^ 2714** 2715** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2716** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2717** 2718** ^The callback function registered by sqlite3_profile() is invoked 2719** as each SQL statement finishes. ^The profile callback contains 2720** the original statement text and an estimate of wall-clock time 2721** of how long that statement took to run. ^The profile callback 2722** time is in units of nanoseconds, however the current implementation 2723** is only capable of millisecond resolution so the six least significant 2724** digits in the time are meaningless. Future versions of SQLite 2725** might provide greater resolution on the profiler callback. The 2726** sqlite3_profile() function is considered experimental and is 2727** subject to change in future versions of SQLite. 2728*/ 2729void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2730SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2731 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2732 2733/* 2734** CAPI3REF: Query Progress Callbacks 2735** METHOD: sqlite3 2736** 2737** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2738** function X to be invoked periodically during long running calls to 2739** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2740** database connection D. An example use for this 2741** interface is to keep a GUI updated during a large query. 2742** 2743** ^The parameter P is passed through as the only parameter to the 2744** callback function X. ^The parameter N is the approximate number of 2745** [virtual machine instructions] that are evaluated between successive 2746** invocations of the callback X. ^If N is less than one then the progress 2747** handler is disabled. 2748** 2749** ^Only a single progress handler may be defined at one time per 2750** [database connection]; setting a new progress handler cancels the 2751** old one. ^Setting parameter X to NULL disables the progress handler. 2752** ^The progress handler is also disabled by setting N to a value less 2753** than 1. 2754** 2755** ^If the progress callback returns non-zero, the operation is 2756** interrupted. This feature can be used to implement a 2757** "Cancel" button on a GUI progress dialog box. 2758** 2759** The progress handler callback must not do anything that will modify 2760** the database connection that invoked the progress handler. 2761** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2762** database connections for the meaning of "modify" in this paragraph. 2763** 2764*/ 2765void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2766 2767/* 2768** CAPI3REF: Opening A New Database Connection 2769** CONSTRUCTOR: sqlite3 2770** 2771** ^These routines open an SQLite database file as specified by the 2772** filename argument. ^The filename argument is interpreted as UTF-8 for 2773** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2774** order for sqlite3_open16(). ^(A [database connection] handle is usually 2775** returned in *ppDb, even if an error occurs. The only exception is that 2776** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2777** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2778** object.)^ ^(If the database is opened (and/or created) successfully, then 2779** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2780** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2781** an English language description of the error following a failure of any 2782** of the sqlite3_open() routines. 2783** 2784** ^The default encoding will be UTF-8 for databases created using 2785** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 2786** created using sqlite3_open16() will be UTF-16 in the native byte order. 2787** 2788** Whether or not an error occurs when it is opened, resources 2789** associated with the [database connection] handle should be released by 2790** passing it to [sqlite3_close()] when it is no longer required. 2791** 2792** The sqlite3_open_v2() interface works like sqlite3_open() 2793** except that it accepts two additional parameters for additional control 2794** over the new database connection. ^(The flags parameter to 2795** sqlite3_open_v2() can take one of 2796** the following three values, optionally combined with the 2797** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2798** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2799** 2800** <dl> 2801** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2802** <dd>The database is opened in read-only mode. If the database does not 2803** already exist, an error is returned.</dd>)^ 2804** 2805** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2806** <dd>The database is opened for reading and writing if possible, or reading 2807** only if the file is write protected by the operating system. In either 2808** case the database must already exist, otherwise an error is returned.</dd>)^ 2809** 2810** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2811** <dd>The database is opened for reading and writing, and is created if 2812** it does not already exist. This is the behavior that is always used for 2813** sqlite3_open() and sqlite3_open16().</dd>)^ 2814** </dl> 2815** 2816** If the 3rd parameter to sqlite3_open_v2() is not one of the 2817** combinations shown above optionally combined with other 2818** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2819** then the behavior is undefined. 2820** 2821** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2822** opens in the multi-thread [threading mode] as long as the single-thread 2823** mode has not been set at compile-time or start-time. ^If the 2824** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2825** in the serialized [threading mode] unless single-thread was 2826** previously selected at compile-time or start-time. 2827** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2828** eligible to use [shared cache mode], regardless of whether or not shared 2829** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2830** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2831** participate in [shared cache mode] even if it is enabled. 2832** 2833** ^The fourth parameter to sqlite3_open_v2() is the name of the 2834** [sqlite3_vfs] object that defines the operating system interface that 2835** the new database connection should use. ^If the fourth parameter is 2836** a NULL pointer then the default [sqlite3_vfs] object is used. 2837** 2838** ^If the filename is ":memory:", then a private, temporary in-memory database 2839** is created for the connection. ^This in-memory database will vanish when 2840** the database connection is closed. Future versions of SQLite might 2841** make use of additional special filenames that begin with the ":" character. 2842** It is recommended that when a database filename actually does begin with 2843** a ":" character you should prefix the filename with a pathname such as 2844** "./" to avoid ambiguity. 2845** 2846** ^If the filename is an empty string, then a private, temporary 2847** on-disk database will be created. ^This private database will be 2848** automatically deleted as soon as the database connection is closed. 2849** 2850** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2851** 2852** ^If [URI filename] interpretation is enabled, and the filename argument 2853** begins with "file:", then the filename is interpreted as a URI. ^URI 2854** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2855** set in the fourth argument to sqlite3_open_v2(), or if it has 2856** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2857** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2858** As of SQLite version 3.7.7, URI filename interpretation is turned off 2859** by default, but future releases of SQLite might enable URI filename 2860** interpretation by default. See "[URI filenames]" for additional 2861** information. 2862** 2863** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2864** authority, then it must be either an empty string or the string 2865** "localhost". ^If the authority is not an empty string or "localhost", an 2866** error is returned to the caller. ^The fragment component of a URI, if 2867** present, is ignored. 2868** 2869** ^SQLite uses the path component of the URI as the name of the disk file 2870** which contains the database. ^If the path begins with a '/' character, 2871** then it is interpreted as an absolute path. ^If the path does not begin 2872** with a '/' (meaning that the authority section is omitted from the URI) 2873** then the path is interpreted as a relative path. 2874** ^(On windows, the first component of an absolute path 2875** is a drive specification (e.g. "C:").)^ 2876** 2877** [[core URI query parameters]] 2878** The query component of a URI may contain parameters that are interpreted 2879** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2880** SQLite and its built-in [VFSes] interpret the 2881** following query parameters: 2882** 2883** <ul> 2884** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2885** a VFS object that provides the operating system interface that should 2886** be used to access the database file on disk. ^If this option is set to 2887** an empty string the default VFS object is used. ^Specifying an unknown 2888** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2889** present, then the VFS specified by the option takes precedence over 2890** the value passed as the fourth parameter to sqlite3_open_v2(). 2891** 2892** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2893** "rwc", or "memory". Attempting to set it to any other value is 2894** an error)^. 2895** ^If "ro" is specified, then the database is opened for read-only 2896** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2897** third argument to sqlite3_open_v2(). ^If the mode option is set to 2898** "rw", then the database is opened for read-write (but not create) 2899** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2900** been set. ^Value "rwc" is equivalent to setting both 2901** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2902** set to "memory" then a pure [in-memory database] that never reads 2903** or writes from disk is used. ^It is an error to specify a value for 2904** the mode parameter that is less restrictive than that specified by 2905** the flags passed in the third parameter to sqlite3_open_v2(). 2906** 2907** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2908** "private". ^Setting it to "shared" is equivalent to setting the 2909** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2910** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2911** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2912** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2913** a URI filename, its value overrides any behavior requested by setting 2914** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2915** 2916** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 2917** [powersafe overwrite] property does or does not apply to the 2918** storage media on which the database file resides. 2919** 2920** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 2921** which if set disables file locking in rollback journal modes. This 2922** is useful for accessing a database on a filesystem that does not 2923** support locking. Caution: Database corruption might result if two 2924** or more processes write to the same database and any one of those 2925** processes uses nolock=1. 2926** 2927** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 2928** parameter that indicates that the database file is stored on 2929** read-only media. ^When immutable is set, SQLite assumes that the 2930** database file cannot be changed, even by a process with higher 2931** privilege, and so the database is opened read-only and all locking 2932** and change detection is disabled. Caution: Setting the immutable 2933** property on a database file that does in fact change can result 2934** in incorrect query results and/or [SQLITE_CORRUPT] errors. 2935** See also: [SQLITE_IOCAP_IMMUTABLE]. 2936** 2937** </ul> 2938** 2939** ^Specifying an unknown parameter in the query component of a URI is not an 2940** error. Future versions of SQLite might understand additional query 2941** parameters. See "[query parameters with special meaning to SQLite]" for 2942** additional information. 2943** 2944** [[URI filename examples]] <h3>URI filename examples</h3> 2945** 2946** <table border="1" align=center cellpadding=5> 2947** <tr><th> URI filenames <th> Results 2948** <tr><td> file:data.db <td> 2949** Open the file "data.db" in the current directory. 2950** <tr><td> file:/home/fred/data.db<br> 2951** file:///home/fred/data.db <br> 2952** file://localhost/home/fred/data.db <br> <td> 2953** Open the database file "/home/fred/data.db". 2954** <tr><td> file://darkstar/home/fred/data.db <td> 2955** An error. "darkstar" is not a recognized authority. 2956** <tr><td style="white-space:nowrap"> 2957** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2958** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2959** C:. Note that the %20 escaping in this example is not strictly 2960** necessary - space characters can be used literally 2961** in URI filenames. 2962** <tr><td> file:data.db?mode=ro&cache=private <td> 2963** Open file "data.db" in the current directory for read-only access. 2964** Regardless of whether or not shared-cache mode is enabled by 2965** default, use a private cache. 2966** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 2967** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 2968** that uses dot-files in place of posix advisory locking. 2969** <tr><td> file:data.db?mode=readonly <td> 2970** An error. "readonly" is not a valid option for the "mode" parameter. 2971** </table> 2972** 2973** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2974** query components of a URI. A hexadecimal escape sequence consists of a 2975** percent sign - "%" - followed by exactly two hexadecimal digits 2976** specifying an octet value. ^Before the path or query components of a 2977** URI filename are interpreted, they are encoded using UTF-8 and all 2978** hexadecimal escape sequences replaced by a single byte containing the 2979** corresponding octet. If this process generates an invalid UTF-8 encoding, 2980** the results are undefined. 2981** 2982** <b>Note to Windows users:</b> The encoding used for the filename argument 2983** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2984** codepage is currently defined. Filenames containing international 2985** characters must be converted to UTF-8 prior to passing them into 2986** sqlite3_open() or sqlite3_open_v2(). 2987** 2988** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2989** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2990** features that require the use of temporary files may fail. 2991** 2992** See also: [sqlite3_temp_directory] 2993*/ 2994int sqlite3_open( 2995 const char *filename, /* Database filename (UTF-8) */ 2996 sqlite3 **ppDb /* OUT: SQLite db handle */ 2997); 2998int sqlite3_open16( 2999 const void *filename, /* Database filename (UTF-16) */ 3000 sqlite3 **ppDb /* OUT: SQLite db handle */ 3001); 3002int sqlite3_open_v2( 3003 const char *filename, /* Database filename (UTF-8) */ 3004 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3005 int flags, /* Flags */ 3006 const char *zVfs /* Name of VFS module to use */ 3007); 3008 3009/* 3010** CAPI3REF: Obtain Values For URI Parameters 3011** 3012** These are utility routines, useful to VFS implementations, that check 3013** to see if a database file was a URI that contained a specific query 3014** parameter, and if so obtains the value of that query parameter. 3015** 3016** If F is the database filename pointer passed into the xOpen() method of 3017** a VFS implementation when the flags parameter to xOpen() has one or 3018** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3019** P is the name of the query parameter, then 3020** sqlite3_uri_parameter(F,P) returns the value of the P 3021** parameter if it exists or a NULL pointer if P does not appear as a 3022** query parameter on F. If P is a query parameter of F 3023** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3024** a pointer to an empty string. 3025** 3026** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3027** parameter and returns true (1) or false (0) according to the value 3028** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3029** value of query parameter P is one of "yes", "true", or "on" in any 3030** case or if the value begins with a non-zero number. The 3031** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3032** query parameter P is one of "no", "false", or "off" in any case or 3033** if the value begins with a numeric zero. If P is not a query 3034** parameter on F or if the value of P is does not match any of the 3035** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3036** 3037** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3038** 64-bit signed integer and returns that integer, or D if P does not 3039** exist. If the value of P is something other than an integer, then 3040** zero is returned. 3041** 3042** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3043** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3044** is not a database file pathname pointer that SQLite passed into the xOpen 3045** VFS method, then the behavior of this routine is undefined and probably 3046** undesirable. 3047*/ 3048const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3049int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3050sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3051 3052 3053/* 3054** CAPI3REF: Error Codes And Messages 3055** METHOD: sqlite3 3056** 3057** ^If the most recent sqlite3_* API call associated with 3058** [database connection] D failed, then the sqlite3_errcode(D) interface 3059** returns the numeric [result code] or [extended result code] for that 3060** API call. 3061** If the most recent API call was successful, 3062** then the return value from sqlite3_errcode() is undefined. 3063** ^The sqlite3_extended_errcode() 3064** interface is the same except that it always returns the 3065** [extended result code] even when extended result codes are 3066** disabled. 3067** 3068** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3069** text that describes the error, as either UTF-8 or UTF-16 respectively. 3070** ^(Memory to hold the error message string is managed internally. 3071** The application does not need to worry about freeing the result. 3072** However, the error string might be overwritten or deallocated by 3073** subsequent calls to other SQLite interface functions.)^ 3074** 3075** ^The sqlite3_errstr() interface returns the English-language text 3076** that describes the [result code], as UTF-8. 3077** ^(Memory to hold the error message string is managed internally 3078** and must not be freed by the application)^. 3079** 3080** When the serialized [threading mode] is in use, it might be the 3081** case that a second error occurs on a separate thread in between 3082** the time of the first error and the call to these interfaces. 3083** When that happens, the second error will be reported since these 3084** interfaces always report the most recent result. To avoid 3085** this, each thread can obtain exclusive use of the [database connection] D 3086** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3087** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3088** all calls to the interfaces listed here are completed. 3089** 3090** If an interface fails with SQLITE_MISUSE, that means the interface 3091** was invoked incorrectly by the application. In that case, the 3092** error code and message may or may not be set. 3093*/ 3094int sqlite3_errcode(sqlite3 *db); 3095int sqlite3_extended_errcode(sqlite3 *db); 3096const char *sqlite3_errmsg(sqlite3*); 3097const void *sqlite3_errmsg16(sqlite3*); 3098const char *sqlite3_errstr(int); 3099 3100/* 3101** CAPI3REF: Prepared Statement Object 3102** KEYWORDS: {prepared statement} {prepared statements} 3103** 3104** An instance of this object represents a single SQL statement that 3105** has been compiled into binary form and is ready to be evaluated. 3106** 3107** Think of each SQL statement as a separate computer program. The 3108** original SQL text is source code. A prepared statement object 3109** is the compiled object code. All SQL must be converted into a 3110** prepared statement before it can be run. 3111** 3112** The life-cycle of a prepared statement object usually goes like this: 3113** 3114** <ol> 3115** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3116** <li> Bind values to [parameters] using the sqlite3_bind_*() 3117** interfaces. 3118** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3119** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3120** to step 2. Do this zero or more times. 3121** <li> Destroy the object using [sqlite3_finalize()]. 3122** </ol> 3123*/ 3124typedef struct sqlite3_stmt sqlite3_stmt; 3125 3126/* 3127** CAPI3REF: Run-time Limits 3128** METHOD: sqlite3 3129** 3130** ^(This interface allows the size of various constructs to be limited 3131** on a connection by connection basis. The first parameter is the 3132** [database connection] whose limit is to be set or queried. The 3133** second parameter is one of the [limit categories] that define a 3134** class of constructs to be size limited. The third parameter is the 3135** new limit for that construct.)^ 3136** 3137** ^If the new limit is a negative number, the limit is unchanged. 3138** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3139** [limits | hard upper bound] 3140** set at compile-time by a C preprocessor macro called 3141** [limits | SQLITE_MAX_<i>NAME</i>]. 3142** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3143** ^Attempts to increase a limit above its hard upper bound are 3144** silently truncated to the hard upper bound. 3145** 3146** ^Regardless of whether or not the limit was changed, the 3147** [sqlite3_limit()] interface returns the prior value of the limit. 3148** ^Hence, to find the current value of a limit without changing it, 3149** simply invoke this interface with the third parameter set to -1. 3150** 3151** Run-time limits are intended for use in applications that manage 3152** both their own internal database and also databases that are controlled 3153** by untrusted external sources. An example application might be a 3154** web browser that has its own databases for storing history and 3155** separate databases controlled by JavaScript applications downloaded 3156** off the Internet. The internal databases can be given the 3157** large, default limits. Databases managed by external sources can 3158** be given much smaller limits designed to prevent a denial of service 3159** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3160** interface to further control untrusted SQL. The size of the database 3161** created by an untrusted script can be contained using the 3162** [max_page_count] [PRAGMA]. 3163** 3164** New run-time limit categories may be added in future releases. 3165*/ 3166int sqlite3_limit(sqlite3*, int id, int newVal); 3167 3168/* 3169** CAPI3REF: Run-Time Limit Categories 3170** KEYWORDS: {limit category} {*limit categories} 3171** 3172** These constants define various performance limits 3173** that can be lowered at run-time using [sqlite3_limit()]. 3174** The synopsis of the meanings of the various limits is shown below. 3175** Additional information is available at [limits | Limits in SQLite]. 3176** 3177** <dl> 3178** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3179** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3180** 3181** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3182** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3183** 3184** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3185** <dd>The maximum number of columns in a table definition or in the 3186** result set of a [SELECT] or the maximum number of columns in an index 3187** or in an ORDER BY or GROUP BY clause.</dd>)^ 3188** 3189** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3190** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3191** 3192** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3193** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3194** 3195** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3196** <dd>The maximum number of instructions in a virtual machine program 3197** used to implement an SQL statement. This limit is not currently 3198** enforced, though that might be added in some future release of 3199** SQLite.</dd>)^ 3200** 3201** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3202** <dd>The maximum number of arguments on a function.</dd>)^ 3203** 3204** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3205** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3206** 3207** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3208** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3209** <dd>The maximum length of the pattern argument to the [LIKE] or 3210** [GLOB] operators.</dd>)^ 3211** 3212** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3213** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3214** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3215** 3216** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3217** <dd>The maximum depth of recursion for triggers.</dd>)^ 3218** 3219** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3220** <dd>The maximum number of auxiliary worker threads that a single 3221** [prepared statement] may start.</dd>)^ 3222** </dl> 3223*/ 3224#define SQLITE_LIMIT_LENGTH 0 3225#define SQLITE_LIMIT_SQL_LENGTH 1 3226#define SQLITE_LIMIT_COLUMN 2 3227#define SQLITE_LIMIT_EXPR_DEPTH 3 3228#define SQLITE_LIMIT_COMPOUND_SELECT 4 3229#define SQLITE_LIMIT_VDBE_OP 5 3230#define SQLITE_LIMIT_FUNCTION_ARG 6 3231#define SQLITE_LIMIT_ATTACHED 7 3232#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3233#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3234#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3235#define SQLITE_LIMIT_WORKER_THREADS 11 3236 3237/* 3238** CAPI3REF: Compiling An SQL Statement 3239** KEYWORDS: {SQL statement compiler} 3240** METHOD: sqlite3 3241** CONSTRUCTOR: sqlite3_stmt 3242** 3243** To execute an SQL query, it must first be compiled into a byte-code 3244** program using one of these routines. 3245** 3246** The first argument, "db", is a [database connection] obtained from a 3247** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3248** [sqlite3_open16()]. The database connection must not have been closed. 3249** 3250** The second argument, "zSql", is the statement to be compiled, encoded 3251** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3252** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3253** use UTF-16. 3254** 3255** ^If the nByte argument is negative, then zSql is read up to the 3256** first zero terminator. ^If nByte is positive, then it is the 3257** number of bytes read from zSql. ^If nByte is zero, then no prepared 3258** statement is generated. 3259** If the caller knows that the supplied string is nul-terminated, then 3260** there is a small performance advantage to passing an nByte parameter that 3261** is the number of bytes in the input string <i>including</i> 3262** the nul-terminator. 3263** 3264** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3265** past the end of the first SQL statement in zSql. These routines only 3266** compile the first statement in zSql, so *pzTail is left pointing to 3267** what remains uncompiled. 3268** 3269** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3270** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3271** to NULL. ^If the input text contains no SQL (if the input is an empty 3272** string or a comment) then *ppStmt is set to NULL. 3273** The calling procedure is responsible for deleting the compiled 3274** SQL statement using [sqlite3_finalize()] after it has finished with it. 3275** ppStmt may not be NULL. 3276** 3277** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3278** otherwise an [error code] is returned. 3279** 3280** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3281** recommended for all new programs. The two older interfaces are retained 3282** for backwards compatibility, but their use is discouraged. 3283** ^In the "v2" interfaces, the prepared statement 3284** that is returned (the [sqlite3_stmt] object) contains a copy of the 3285** original SQL text. This causes the [sqlite3_step()] interface to 3286** behave differently in three ways: 3287** 3288** <ol> 3289** <li> 3290** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3291** always used to do, [sqlite3_step()] will automatically recompile the SQL 3292** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3293** retries will occur before sqlite3_step() gives up and returns an error. 3294** </li> 3295** 3296** <li> 3297** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3298** [error codes] or [extended error codes]. ^The legacy behavior was that 3299** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3300** and the application would have to make a second call to [sqlite3_reset()] 3301** in order to find the underlying cause of the problem. With the "v2" prepare 3302** interfaces, the underlying reason for the error is returned immediately. 3303** </li> 3304** 3305** <li> 3306** ^If the specific value bound to [parameter | host parameter] in the 3307** WHERE clause might influence the choice of query plan for a statement, 3308** then the statement will be automatically recompiled, as if there had been 3309** a schema change, on the first [sqlite3_step()] call following any change 3310** to the [sqlite3_bind_text | bindings] of that [parameter]. 3311** ^The specific value of WHERE-clause [parameter] might influence the 3312** choice of query plan if the parameter is the left-hand side of a [LIKE] 3313** or [GLOB] operator or if the parameter is compared to an indexed column 3314** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3315** </li> 3316** </ol> 3317*/ 3318int sqlite3_prepare( 3319 sqlite3 *db, /* Database handle */ 3320 const char *zSql, /* SQL statement, UTF-8 encoded */ 3321 int nByte, /* Maximum length of zSql in bytes. */ 3322 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3323 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3324); 3325int sqlite3_prepare_v2( 3326 sqlite3 *db, /* Database handle */ 3327 const char *zSql, /* SQL statement, UTF-8 encoded */ 3328 int nByte, /* Maximum length of zSql in bytes. */ 3329 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3330 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3331); 3332int sqlite3_prepare16( 3333 sqlite3 *db, /* Database handle */ 3334 const void *zSql, /* SQL statement, UTF-16 encoded */ 3335 int nByte, /* Maximum length of zSql in bytes. */ 3336 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3337 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3338); 3339int sqlite3_prepare16_v2( 3340 sqlite3 *db, /* Database handle */ 3341 const void *zSql, /* SQL statement, UTF-16 encoded */ 3342 int nByte, /* Maximum length of zSql in bytes. */ 3343 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3344 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3345); 3346 3347/* 3348** CAPI3REF: Retrieving Statement SQL 3349** METHOD: sqlite3_stmt 3350** 3351** ^This interface can be used to retrieve a saved copy of the original 3352** SQL text used to create a [prepared statement] if that statement was 3353** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3354*/ 3355const char *sqlite3_sql(sqlite3_stmt *pStmt); 3356 3357/* 3358** CAPI3REF: Determine If An SQL Statement Writes The Database 3359** METHOD: sqlite3_stmt 3360** 3361** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3362** and only if the [prepared statement] X makes no direct changes to 3363** the content of the database file. 3364** 3365** Note that [application-defined SQL functions] or 3366** [virtual tables] might change the database indirectly as a side effect. 3367** ^(For example, if an application defines a function "eval()" that 3368** calls [sqlite3_exec()], then the following SQL statement would 3369** change the database file through side-effects: 3370** 3371** <blockquote><pre> 3372** SELECT eval('DELETE FROM t1') FROM t2; 3373** </pre></blockquote> 3374** 3375** But because the [SELECT] statement does not change the database file 3376** directly, sqlite3_stmt_readonly() would still return true.)^ 3377** 3378** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3379** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3380** since the statements themselves do not actually modify the database but 3381** rather they control the timing of when other statements modify the 3382** database. ^The [ATTACH] and [DETACH] statements also cause 3383** sqlite3_stmt_readonly() to return true since, while those statements 3384** change the configuration of a database connection, they do not make 3385** changes to the content of the database files on disk. 3386*/ 3387int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3388 3389/* 3390** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3391** METHOD: sqlite3_stmt 3392** 3393** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3394** [prepared statement] S has been stepped at least once using 3395** [sqlite3_step(S)] but has neither run to completion (returned 3396** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3397** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3398** interface returns false if S is a NULL pointer. If S is not a 3399** NULL pointer and is not a pointer to a valid [prepared statement] 3400** object, then the behavior is undefined and probably undesirable. 3401** 3402** This interface can be used in combination [sqlite3_next_stmt()] 3403** to locate all prepared statements associated with a database 3404** connection that are in need of being reset. This can be used, 3405** for example, in diagnostic routines to search for prepared 3406** statements that are holding a transaction open. 3407*/ 3408int sqlite3_stmt_busy(sqlite3_stmt*); 3409 3410/* 3411** CAPI3REF: Dynamically Typed Value Object 3412** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3413** 3414** SQLite uses the sqlite3_value object to represent all values 3415** that can be stored in a database table. SQLite uses dynamic typing 3416** for the values it stores. ^Values stored in sqlite3_value objects 3417** can be integers, floating point values, strings, BLOBs, or NULL. 3418** 3419** An sqlite3_value object may be either "protected" or "unprotected". 3420** Some interfaces require a protected sqlite3_value. Other interfaces 3421** will accept either a protected or an unprotected sqlite3_value. 3422** Every interface that accepts sqlite3_value arguments specifies 3423** whether or not it requires a protected sqlite3_value. The 3424** [sqlite3_value_dup()] interface can be used to construct a new 3425** protected sqlite3_value from an unprotected sqlite3_value. 3426** 3427** The terms "protected" and "unprotected" refer to whether or not 3428** a mutex is held. An internal mutex is held for a protected 3429** sqlite3_value object but no mutex is held for an unprotected 3430** sqlite3_value object. If SQLite is compiled to be single-threaded 3431** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3432** or if SQLite is run in one of reduced mutex modes 3433** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3434** then there is no distinction between protected and unprotected 3435** sqlite3_value objects and they can be used interchangeably. However, 3436** for maximum code portability it is recommended that applications 3437** still make the distinction between protected and unprotected 3438** sqlite3_value objects even when not strictly required. 3439** 3440** ^The sqlite3_value objects that are passed as parameters into the 3441** implementation of [application-defined SQL functions] are protected. 3442** ^The sqlite3_value object returned by 3443** [sqlite3_column_value()] is unprotected. 3444** Unprotected sqlite3_value objects may only be used with 3445** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3446** The [sqlite3_value_blob | sqlite3_value_type()] family of 3447** interfaces require protected sqlite3_value objects. 3448*/ 3449typedef struct Mem sqlite3_value; 3450 3451/* 3452** CAPI3REF: SQL Function Context Object 3453** 3454** The context in which an SQL function executes is stored in an 3455** sqlite3_context object. ^A pointer to an sqlite3_context object 3456** is always first parameter to [application-defined SQL functions]. 3457** The application-defined SQL function implementation will pass this 3458** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3459** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3460** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3461** and/or [sqlite3_set_auxdata()]. 3462*/ 3463typedef struct sqlite3_context sqlite3_context; 3464 3465/* 3466** CAPI3REF: Binding Values To Prepared Statements 3467** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3468** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3469** METHOD: sqlite3_stmt 3470** 3471** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3472** literals may be replaced by a [parameter] that matches one of following 3473** templates: 3474** 3475** <ul> 3476** <li> ? 3477** <li> ?NNN 3478** <li> :VVV 3479** <li> @VVV 3480** <li> $VVV 3481** </ul> 3482** 3483** In the templates above, NNN represents an integer literal, 3484** and VVV represents an alphanumeric identifier.)^ ^The values of these 3485** parameters (also called "host parameter names" or "SQL parameters") 3486** can be set using the sqlite3_bind_*() routines defined here. 3487** 3488** ^The first argument to the sqlite3_bind_*() routines is always 3489** a pointer to the [sqlite3_stmt] object returned from 3490** [sqlite3_prepare_v2()] or its variants. 3491** 3492** ^The second argument is the index of the SQL parameter to be set. 3493** ^The leftmost SQL parameter has an index of 1. ^When the same named 3494** SQL parameter is used more than once, second and subsequent 3495** occurrences have the same index as the first occurrence. 3496** ^The index for named parameters can be looked up using the 3497** [sqlite3_bind_parameter_index()] API if desired. ^The index 3498** for "?NNN" parameters is the value of NNN. 3499** ^The NNN value must be between 1 and the [sqlite3_limit()] 3500** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3501** 3502** ^The third argument is the value to bind to the parameter. 3503** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3504** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3505** is ignored and the end result is the same as sqlite3_bind_null(). 3506** 3507** ^(In those routines that have a fourth argument, its value is the 3508** number of bytes in the parameter. To be clear: the value is the 3509** number of <u>bytes</u> in the value, not the number of characters.)^ 3510** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3511** is negative, then the length of the string is 3512** the number of bytes up to the first zero terminator. 3513** If the fourth parameter to sqlite3_bind_blob() is negative, then 3514** the behavior is undefined. 3515** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3516** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3517** that parameter must be the byte offset 3518** where the NUL terminator would occur assuming the string were NUL 3519** terminated. If any NUL characters occur at byte offsets less than 3520** the value of the fourth parameter then the resulting string value will 3521** contain embedded NULs. The result of expressions involving strings 3522** with embedded NULs is undefined. 3523** 3524** ^The fifth argument to the BLOB and string binding interfaces 3525** is a destructor used to dispose of the BLOB or 3526** string after SQLite has finished with it. ^The destructor is called 3527** to dispose of the BLOB or string even if the call to bind API fails. 3528** ^If the fifth argument is 3529** the special value [SQLITE_STATIC], then SQLite assumes that the 3530** information is in static, unmanaged space and does not need to be freed. 3531** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3532** SQLite makes its own private copy of the data immediately, before 3533** the sqlite3_bind_*() routine returns. 3534** 3535** ^The sixth argument to sqlite3_bind_text64() must be one of 3536** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3537** to specify the encoding of the text in the third parameter. If 3538** the sixth argument to sqlite3_bind_text64() is not one of the 3539** allowed values shown above, or if the text encoding is different 3540** from the encoding specified by the sixth parameter, then the behavior 3541** is undefined. 3542** 3543** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3544** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3545** (just an integer to hold its size) while it is being processed. 3546** Zeroblobs are intended to serve as placeholders for BLOBs whose 3547** content is later written using 3548** [sqlite3_blob_open | incremental BLOB I/O] routines. 3549** ^A negative value for the zeroblob results in a zero-length BLOB. 3550** 3551** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3552** for the [prepared statement] or with a prepared statement for which 3553** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3554** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3555** routine is passed a [prepared statement] that has been finalized, the 3556** result is undefined and probably harmful. 3557** 3558** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3559** ^Unbound parameters are interpreted as NULL. 3560** 3561** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3562** [error code] if anything goes wrong. 3563** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3564** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3565** [SQLITE_MAX_LENGTH]. 3566** ^[SQLITE_RANGE] is returned if the parameter 3567** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3568** 3569** See also: [sqlite3_bind_parameter_count()], 3570** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3571*/ 3572int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3573int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3574 void(*)(void*)); 3575int sqlite3_bind_double(sqlite3_stmt*, int, double); 3576int sqlite3_bind_int(sqlite3_stmt*, int, int); 3577int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3578int sqlite3_bind_null(sqlite3_stmt*, int); 3579int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3580int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3581int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3582 void(*)(void*), unsigned char encoding); 3583int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3584int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3585int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3586 3587/* 3588** CAPI3REF: Number Of SQL Parameters 3589** METHOD: sqlite3_stmt 3590** 3591** ^This routine can be used to find the number of [SQL parameters] 3592** in a [prepared statement]. SQL parameters are tokens of the 3593** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3594** placeholders for values that are [sqlite3_bind_blob | bound] 3595** to the parameters at a later time. 3596** 3597** ^(This routine actually returns the index of the largest (rightmost) 3598** parameter. For all forms except ?NNN, this will correspond to the 3599** number of unique parameters. If parameters of the ?NNN form are used, 3600** there may be gaps in the list.)^ 3601** 3602** See also: [sqlite3_bind_blob|sqlite3_bind()], 3603** [sqlite3_bind_parameter_name()], and 3604** [sqlite3_bind_parameter_index()]. 3605*/ 3606int sqlite3_bind_parameter_count(sqlite3_stmt*); 3607 3608/* 3609** CAPI3REF: Name Of A Host Parameter 3610** METHOD: sqlite3_stmt 3611** 3612** ^The sqlite3_bind_parameter_name(P,N) interface returns 3613** the name of the N-th [SQL parameter] in the [prepared statement] P. 3614** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3615** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3616** respectively. 3617** In other words, the initial ":" or "$" or "@" or "?" 3618** is included as part of the name.)^ 3619** ^Parameters of the form "?" without a following integer have no name 3620** and are referred to as "nameless" or "anonymous parameters". 3621** 3622** ^The first host parameter has an index of 1, not 0. 3623** 3624** ^If the value N is out of range or if the N-th parameter is 3625** nameless, then NULL is returned. ^The returned string is 3626** always in UTF-8 encoding even if the named parameter was 3627** originally specified as UTF-16 in [sqlite3_prepare16()] or 3628** [sqlite3_prepare16_v2()]. 3629** 3630** See also: [sqlite3_bind_blob|sqlite3_bind()], 3631** [sqlite3_bind_parameter_count()], and 3632** [sqlite3_bind_parameter_index()]. 3633*/ 3634const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3635 3636/* 3637** CAPI3REF: Index Of A Parameter With A Given Name 3638** METHOD: sqlite3_stmt 3639** 3640** ^Return the index of an SQL parameter given its name. ^The 3641** index value returned is suitable for use as the second 3642** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3643** is returned if no matching parameter is found. ^The parameter 3644** name must be given in UTF-8 even if the original statement 3645** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3646** 3647** See also: [sqlite3_bind_blob|sqlite3_bind()], 3648** [sqlite3_bind_parameter_count()], and 3649** [sqlite3_bind_parameter_name()]. 3650*/ 3651int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3652 3653/* 3654** CAPI3REF: Reset All Bindings On A Prepared Statement 3655** METHOD: sqlite3_stmt 3656** 3657** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3658** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3659** ^Use this routine to reset all host parameters to NULL. 3660*/ 3661int sqlite3_clear_bindings(sqlite3_stmt*); 3662 3663/* 3664** CAPI3REF: Number Of Columns In A Result Set 3665** METHOD: sqlite3_stmt 3666** 3667** ^Return the number of columns in the result set returned by the 3668** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3669** statement that does not return data (for example an [UPDATE]). 3670** 3671** See also: [sqlite3_data_count()] 3672*/ 3673int sqlite3_column_count(sqlite3_stmt *pStmt); 3674 3675/* 3676** CAPI3REF: Column Names In A Result Set 3677** METHOD: sqlite3_stmt 3678** 3679** ^These routines return the name assigned to a particular column 3680** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3681** interface returns a pointer to a zero-terminated UTF-8 string 3682** and sqlite3_column_name16() returns a pointer to a zero-terminated 3683** UTF-16 string. ^The first parameter is the [prepared statement] 3684** that implements the [SELECT] statement. ^The second parameter is the 3685** column number. ^The leftmost column is number 0. 3686** 3687** ^The returned string pointer is valid until either the [prepared statement] 3688** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3689** reprepared by the first call to [sqlite3_step()] for a particular run 3690** or until the next call to 3691** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3692** 3693** ^If sqlite3_malloc() fails during the processing of either routine 3694** (for example during a conversion from UTF-8 to UTF-16) then a 3695** NULL pointer is returned. 3696** 3697** ^The name of a result column is the value of the "AS" clause for 3698** that column, if there is an AS clause. If there is no AS clause 3699** then the name of the column is unspecified and may change from 3700** one release of SQLite to the next. 3701*/ 3702const char *sqlite3_column_name(sqlite3_stmt*, int N); 3703const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3704 3705/* 3706** CAPI3REF: Source Of Data In A Query Result 3707** METHOD: sqlite3_stmt 3708** 3709** ^These routines provide a means to determine the database, table, and 3710** table column that is the origin of a particular result column in 3711** [SELECT] statement. 3712** ^The name of the database or table or column can be returned as 3713** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3714** the database name, the _table_ routines return the table name, and 3715** the origin_ routines return the column name. 3716** ^The returned string is valid until the [prepared statement] is destroyed 3717** using [sqlite3_finalize()] or until the statement is automatically 3718** reprepared by the first call to [sqlite3_step()] for a particular run 3719** or until the same information is requested 3720** again in a different encoding. 3721** 3722** ^The names returned are the original un-aliased names of the 3723** database, table, and column. 3724** 3725** ^The first argument to these interfaces is a [prepared statement]. 3726** ^These functions return information about the Nth result column returned by 3727** the statement, where N is the second function argument. 3728** ^The left-most column is column 0 for these routines. 3729** 3730** ^If the Nth column returned by the statement is an expression or 3731** subquery and is not a column value, then all of these functions return 3732** NULL. ^These routine might also return NULL if a memory allocation error 3733** occurs. ^Otherwise, they return the name of the attached database, table, 3734** or column that query result column was extracted from. 3735** 3736** ^As with all other SQLite APIs, those whose names end with "16" return 3737** UTF-16 encoded strings and the other functions return UTF-8. 3738** 3739** ^These APIs are only available if the library was compiled with the 3740** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3741** 3742** If two or more threads call one or more of these routines against the same 3743** prepared statement and column at the same time then the results are 3744** undefined. 3745** 3746** If two or more threads call one or more 3747** [sqlite3_column_database_name | column metadata interfaces] 3748** for the same [prepared statement] and result column 3749** at the same time then the results are undefined. 3750*/ 3751const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3752const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3753const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3754const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3755const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3756const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3757 3758/* 3759** CAPI3REF: Declared Datatype Of A Query Result 3760** METHOD: sqlite3_stmt 3761** 3762** ^(The first parameter is a [prepared statement]. 3763** If this statement is a [SELECT] statement and the Nth column of the 3764** returned result set of that [SELECT] is a table column (not an 3765** expression or subquery) then the declared type of the table 3766** column is returned.)^ ^If the Nth column of the result set is an 3767** expression or subquery, then a NULL pointer is returned. 3768** ^The returned string is always UTF-8 encoded. 3769** 3770** ^(For example, given the database schema: 3771** 3772** CREATE TABLE t1(c1 VARIANT); 3773** 3774** and the following statement to be compiled: 3775** 3776** SELECT c1 + 1, c1 FROM t1; 3777** 3778** this routine would return the string "VARIANT" for the second result 3779** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3780** 3781** ^SQLite uses dynamic run-time typing. ^So just because a column 3782** is declared to contain a particular type does not mean that the 3783** data stored in that column is of the declared type. SQLite is 3784** strongly typed, but the typing is dynamic not static. ^Type 3785** is associated with individual values, not with the containers 3786** used to hold those values. 3787*/ 3788const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3789const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3790 3791/* 3792** CAPI3REF: Evaluate An SQL Statement 3793** METHOD: sqlite3_stmt 3794** 3795** After a [prepared statement] has been prepared using either 3796** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3797** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3798** must be called one or more times to evaluate the statement. 3799** 3800** The details of the behavior of the sqlite3_step() interface depend 3801** on whether the statement was prepared using the newer "v2" interface 3802** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3803** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3804** new "v2" interface is recommended for new applications but the legacy 3805** interface will continue to be supported. 3806** 3807** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3808** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3809** ^With the "v2" interface, any of the other [result codes] or 3810** [extended result codes] might be returned as well. 3811** 3812** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3813** database locks it needs to do its job. ^If the statement is a [COMMIT] 3814** or occurs outside of an explicit transaction, then you can retry the 3815** statement. If the statement is not a [COMMIT] and occurs within an 3816** explicit transaction then you should rollback the transaction before 3817** continuing. 3818** 3819** ^[SQLITE_DONE] means that the statement has finished executing 3820** successfully. sqlite3_step() should not be called again on this virtual 3821** machine without first calling [sqlite3_reset()] to reset the virtual 3822** machine back to its initial state. 3823** 3824** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3825** is returned each time a new row of data is ready for processing by the 3826** caller. The values may be accessed using the [column access functions]. 3827** sqlite3_step() is called again to retrieve the next row of data. 3828** 3829** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3830** violation) has occurred. sqlite3_step() should not be called again on 3831** the VM. More information may be found by calling [sqlite3_errmsg()]. 3832** ^With the legacy interface, a more specific error code (for example, 3833** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3834** can be obtained by calling [sqlite3_reset()] on the 3835** [prepared statement]. ^In the "v2" interface, 3836** the more specific error code is returned directly by sqlite3_step(). 3837** 3838** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3839** Perhaps it was called on a [prepared statement] that has 3840** already been [sqlite3_finalize | finalized] or on one that had 3841** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3842** be the case that the same database connection is being used by two or 3843** more threads at the same moment in time. 3844** 3845** For all versions of SQLite up to and including 3.6.23.1, a call to 3846** [sqlite3_reset()] was required after sqlite3_step() returned anything 3847** other than [SQLITE_ROW] before any subsequent invocation of 3848** sqlite3_step(). Failure to reset the prepared statement using 3849** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3850** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3851** calling [sqlite3_reset()] automatically in this circumstance rather 3852** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3853** break because any application that ever receives an SQLITE_MISUSE error 3854** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3855** can be used to restore the legacy behavior. 3856** 3857** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3858** API always returns a generic error code, [SQLITE_ERROR], following any 3859** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3860** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3861** specific [error codes] that better describes the error. 3862** We admit that this is a goofy design. The problem has been fixed 3863** with the "v2" interface. If you prepare all of your SQL statements 3864** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3865** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3866** then the more specific [error codes] are returned directly 3867** by sqlite3_step(). The use of the "v2" interface is recommended. 3868*/ 3869int sqlite3_step(sqlite3_stmt*); 3870 3871/* 3872** CAPI3REF: Number of columns in a result set 3873** METHOD: sqlite3_stmt 3874** 3875** ^The sqlite3_data_count(P) interface returns the number of columns in the 3876** current row of the result set of [prepared statement] P. 3877** ^If prepared statement P does not have results ready to return 3878** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3879** interfaces) then sqlite3_data_count(P) returns 0. 3880** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3881** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3882** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3883** will return non-zero if previous call to [sqlite3_step](P) returned 3884** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3885** where it always returns zero since each step of that multi-step 3886** pragma returns 0 columns of data. 3887** 3888** See also: [sqlite3_column_count()] 3889*/ 3890int sqlite3_data_count(sqlite3_stmt *pStmt); 3891 3892/* 3893** CAPI3REF: Fundamental Datatypes 3894** KEYWORDS: SQLITE_TEXT 3895** 3896** ^(Every value in SQLite has one of five fundamental datatypes: 3897** 3898** <ul> 3899** <li> 64-bit signed integer 3900** <li> 64-bit IEEE floating point number 3901** <li> string 3902** <li> BLOB 3903** <li> NULL 3904** </ul>)^ 3905** 3906** These constants are codes for each of those types. 3907** 3908** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3909** for a completely different meaning. Software that links against both 3910** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3911** SQLITE_TEXT. 3912*/ 3913#define SQLITE_INTEGER 1 3914#define SQLITE_FLOAT 2 3915#define SQLITE_BLOB 4 3916#define SQLITE_NULL 5 3917#ifdef SQLITE_TEXT 3918# undef SQLITE_TEXT 3919#else 3920# define SQLITE_TEXT 3 3921#endif 3922#define SQLITE3_TEXT 3 3923 3924/* 3925** CAPI3REF: Result Values From A Query 3926** KEYWORDS: {column access functions} 3927** METHOD: sqlite3_stmt 3928** 3929** ^These routines return information about a single column of the current 3930** result row of a query. ^In every case the first argument is a pointer 3931** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3932** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3933** and the second argument is the index of the column for which information 3934** should be returned. ^The leftmost column of the result set has the index 0. 3935** ^The number of columns in the result can be determined using 3936** [sqlite3_column_count()]. 3937** 3938** If the SQL statement does not currently point to a valid row, or if the 3939** column index is out of range, the result is undefined. 3940** These routines may only be called when the most recent call to 3941** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3942** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3943** If any of these routines are called after [sqlite3_reset()] or 3944** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3945** something other than [SQLITE_ROW], the results are undefined. 3946** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3947** are called from a different thread while any of these routines 3948** are pending, then the results are undefined. 3949** 3950** ^The sqlite3_column_type() routine returns the 3951** [SQLITE_INTEGER | datatype code] for the initial data type 3952** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3953** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3954** returned by sqlite3_column_type() is only meaningful if no type 3955** conversions have occurred as described below. After a type conversion, 3956** the value returned by sqlite3_column_type() is undefined. Future 3957** versions of SQLite may change the behavior of sqlite3_column_type() 3958** following a type conversion. 3959** 3960** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3961** routine returns the number of bytes in that BLOB or string. 3962** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3963** the string to UTF-8 and then returns the number of bytes. 3964** ^If the result is a numeric value then sqlite3_column_bytes() uses 3965** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3966** the number of bytes in that string. 3967** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3968** 3969** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3970** routine returns the number of bytes in that BLOB or string. 3971** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3972** the string to UTF-16 and then returns the number of bytes. 3973** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3974** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3975** the number of bytes in that string. 3976** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3977** 3978** ^The values returned by [sqlite3_column_bytes()] and 3979** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3980** of the string. ^For clarity: the values returned by 3981** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3982** bytes in the string, not the number of characters. 3983** 3984** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3985** even empty strings, are always zero-terminated. ^The return 3986** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3987** 3988** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 3989** [unprotected sqlite3_value] object. In a multithreaded environment, 3990** an unprotected sqlite3_value object may only be used safely with 3991** [sqlite3_bind_value()] and [sqlite3_result_value()]. 3992** If the [unprotected sqlite3_value] object returned by 3993** [sqlite3_column_value()] is used in any other way, including calls 3994** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3995** or [sqlite3_value_bytes()], the behavior is not threadsafe. 3996** 3997** These routines attempt to convert the value where appropriate. ^For 3998** example, if the internal representation is FLOAT and a text result 3999** is requested, [sqlite3_snprintf()] is used internally to perform the 4000** conversion automatically. ^(The following table details the conversions 4001** that are applied: 4002** 4003** <blockquote> 4004** <table border="1"> 4005** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4006** 4007** <tr><td> NULL <td> INTEGER <td> Result is 0 4008** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4009** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4010** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4011** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4012** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4013** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4014** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4015** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4016** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4017** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4018** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4019** <tr><td> TEXT <td> BLOB <td> No change 4020** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4021** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4022** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4023** </table> 4024** </blockquote>)^ 4025** 4026** Note that when type conversions occur, pointers returned by prior 4027** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4028** sqlite3_column_text16() may be invalidated. 4029** Type conversions and pointer invalidations might occur 4030** in the following cases: 4031** 4032** <ul> 4033** <li> The initial content is a BLOB and sqlite3_column_text() or 4034** sqlite3_column_text16() is called. A zero-terminator might 4035** need to be added to the string.</li> 4036** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4037** sqlite3_column_text16() is called. The content must be converted 4038** to UTF-16.</li> 4039** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4040** sqlite3_column_text() is called. The content must be converted 4041** to UTF-8.</li> 4042** </ul> 4043** 4044** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4045** not invalidate a prior pointer, though of course the content of the buffer 4046** that the prior pointer references will have been modified. Other kinds 4047** of conversion are done in place when it is possible, but sometimes they 4048** are not possible and in those cases prior pointers are invalidated. 4049** 4050** The safest policy is to invoke these routines 4051** in one of the following ways: 4052** 4053** <ul> 4054** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4055** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4056** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4057** </ul> 4058** 4059** In other words, you should call sqlite3_column_text(), 4060** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4061** into the desired format, then invoke sqlite3_column_bytes() or 4062** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4063** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4064** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4065** with calls to sqlite3_column_bytes(). 4066** 4067** ^The pointers returned are valid until a type conversion occurs as 4068** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4069** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4070** and BLOBs is freed automatically. Do <em>not</em> pass the pointers returned 4071** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4072** [sqlite3_free()]. 4073** 4074** ^(If a memory allocation error occurs during the evaluation of any 4075** of these routines, a default value is returned. The default value 4076** is either the integer 0, the floating point number 0.0, or a NULL 4077** pointer. Subsequent calls to [sqlite3_errcode()] will return 4078** [SQLITE_NOMEM].)^ 4079*/ 4080const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4081int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4082int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4083double sqlite3_column_double(sqlite3_stmt*, int iCol); 4084int sqlite3_column_int(sqlite3_stmt*, int iCol); 4085sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4086const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4087const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4088int sqlite3_column_type(sqlite3_stmt*, int iCol); 4089sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4090 4091/* 4092** CAPI3REF: Destroy A Prepared Statement Object 4093** DESTRUCTOR: sqlite3_stmt 4094** 4095** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4096** ^If the most recent evaluation of the statement encountered no errors 4097** or if the statement is never been evaluated, then sqlite3_finalize() returns 4098** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4099** sqlite3_finalize(S) returns the appropriate [error code] or 4100** [extended error code]. 4101** 4102** ^The sqlite3_finalize(S) routine can be called at any point during 4103** the life cycle of [prepared statement] S: 4104** before statement S is ever evaluated, after 4105** one or more calls to [sqlite3_reset()], or after any call 4106** to [sqlite3_step()] regardless of whether or not the statement has 4107** completed execution. 4108** 4109** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4110** 4111** The application must finalize every [prepared statement] in order to avoid 4112** resource leaks. It is a grievous error for the application to try to use 4113** a prepared statement after it has been finalized. Any use of a prepared 4114** statement after it has been finalized can result in undefined and 4115** undesirable behavior such as segfaults and heap corruption. 4116*/ 4117int sqlite3_finalize(sqlite3_stmt *pStmt); 4118 4119/* 4120** CAPI3REF: Reset A Prepared Statement Object 4121** METHOD: sqlite3_stmt 4122** 4123** The sqlite3_reset() function is called to reset a [prepared statement] 4124** object back to its initial state, ready to be re-executed. 4125** ^Any SQL statement variables that had values bound to them using 4126** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4127** Use [sqlite3_clear_bindings()] to reset the bindings. 4128** 4129** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4130** back to the beginning of its program. 4131** 4132** ^If the most recent call to [sqlite3_step(S)] for the 4133** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4134** or if [sqlite3_step(S)] has never before been called on S, 4135** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4136** 4137** ^If the most recent call to [sqlite3_step(S)] for the 4138** [prepared statement] S indicated an error, then 4139** [sqlite3_reset(S)] returns an appropriate [error code]. 4140** 4141** ^The [sqlite3_reset(S)] interface does not change the values 4142** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4143*/ 4144int sqlite3_reset(sqlite3_stmt *pStmt); 4145 4146/* 4147** CAPI3REF: Create Or Redefine SQL Functions 4148** KEYWORDS: {function creation routines} 4149** KEYWORDS: {application-defined SQL function} 4150** KEYWORDS: {application-defined SQL functions} 4151** METHOD: sqlite3 4152** 4153** ^These functions (collectively known as "function creation routines") 4154** are used to add SQL functions or aggregates or to redefine the behavior 4155** of existing SQL functions or aggregates. The only differences between 4156** these routines are the text encoding expected for 4157** the second parameter (the name of the function being created) 4158** and the presence or absence of a destructor callback for 4159** the application data pointer. 4160** 4161** ^The first parameter is the [database connection] to which the SQL 4162** function is to be added. ^If an application uses more than one database 4163** connection then application-defined SQL functions must be added 4164** to each database connection separately. 4165** 4166** ^The second parameter is the name of the SQL function to be created or 4167** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4168** representation, exclusive of the zero-terminator. ^Note that the name 4169** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4170** ^Any attempt to create a function with a longer name 4171** will result in [SQLITE_MISUSE] being returned. 4172** 4173** ^The third parameter (nArg) 4174** is the number of arguments that the SQL function or 4175** aggregate takes. ^If this parameter is -1, then the SQL function or 4176** aggregate may take any number of arguments between 0 and the limit 4177** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4178** parameter is less than -1 or greater than 127 then the behavior is 4179** undefined. 4180** 4181** ^The fourth parameter, eTextRep, specifies what 4182** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4183** its parameters. The application should set this parameter to 4184** [SQLITE_UTF16LE] if the function implementation invokes 4185** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4186** implementation invokes [sqlite3_value_text16be()] on an input, or 4187** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4188** otherwise. ^The same SQL function may be registered multiple times using 4189** different preferred text encodings, with different implementations for 4190** each encoding. 4191** ^When multiple implementations of the same function are available, SQLite 4192** will pick the one that involves the least amount of data conversion. 4193** 4194** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4195** to signal that the function will always return the same result given 4196** the same inputs within a single SQL statement. Most SQL functions are 4197** deterministic. The built-in [random()] SQL function is an example of a 4198** function that is not deterministic. The SQLite query planner is able to 4199** perform additional optimizations on deterministic functions, so use 4200** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4201** 4202** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4203** function can gain access to this pointer using [sqlite3_user_data()].)^ 4204** 4205** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4206** pointers to C-language functions that implement the SQL function or 4207** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4208** callback only; NULL pointers must be passed as the xStep and xFinal 4209** parameters. ^An aggregate SQL function requires an implementation of xStep 4210** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4211** SQL function or aggregate, pass NULL pointers for all three function 4212** callbacks. 4213** 4214** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4215** then it is destructor for the application data pointer. 4216** The destructor is invoked when the function is deleted, either by being 4217** overloaded or when the database connection closes.)^ 4218** ^The destructor is also invoked if the call to 4219** sqlite3_create_function_v2() fails. 4220** ^When the destructor callback of the tenth parameter is invoked, it 4221** is passed a single argument which is a copy of the application data 4222** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4223** 4224** ^It is permitted to register multiple implementations of the same 4225** functions with the same name but with either differing numbers of 4226** arguments or differing preferred text encodings. ^SQLite will use 4227** the implementation that most closely matches the way in which the 4228** SQL function is used. ^A function implementation with a non-negative 4229** nArg parameter is a better match than a function implementation with 4230** a negative nArg. ^A function where the preferred text encoding 4231** matches the database encoding is a better 4232** match than a function where the encoding is different. 4233** ^A function where the encoding difference is between UTF16le and UTF16be 4234** is a closer match than a function where the encoding difference is 4235** between UTF8 and UTF16. 4236** 4237** ^Built-in functions may be overloaded by new application-defined functions. 4238** 4239** ^An application-defined function is permitted to call other 4240** SQLite interfaces. However, such calls must not 4241** close the database connection nor finalize or reset the prepared 4242** statement in which the function is running. 4243*/ 4244int sqlite3_create_function( 4245 sqlite3 *db, 4246 const char *zFunctionName, 4247 int nArg, 4248 int eTextRep, 4249 void *pApp, 4250 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4251 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4252 void (*xFinal)(sqlite3_context*) 4253); 4254int sqlite3_create_function16( 4255 sqlite3 *db, 4256 const void *zFunctionName, 4257 int nArg, 4258 int eTextRep, 4259 void *pApp, 4260 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4261 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4262 void (*xFinal)(sqlite3_context*) 4263); 4264int sqlite3_create_function_v2( 4265 sqlite3 *db, 4266 const char *zFunctionName, 4267 int nArg, 4268 int eTextRep, 4269 void *pApp, 4270 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4271 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4272 void (*xFinal)(sqlite3_context*), 4273 void(*xDestroy)(void*) 4274); 4275 4276/* 4277** CAPI3REF: Text Encodings 4278** 4279** These constant define integer codes that represent the various 4280** text encodings supported by SQLite. 4281*/ 4282#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4283#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4284#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4285#define SQLITE_UTF16 4 /* Use native byte order */ 4286#define SQLITE_ANY 5 /* Deprecated */ 4287#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4288 4289/* 4290** CAPI3REF: Function Flags 4291** 4292** These constants may be ORed together with the 4293** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4294** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4295** [sqlite3_create_function_v2()]. 4296*/ 4297#define SQLITE_DETERMINISTIC 0x800 4298 4299/* 4300** CAPI3REF: Deprecated Functions 4301** DEPRECATED 4302** 4303** These functions are [deprecated]. In order to maintain 4304** backwards compatibility with older code, these functions continue 4305** to be supported. However, new applications should avoid 4306** the use of these functions. To encourage programmers to avoid 4307** these functions, we will not explain what they do. 4308*/ 4309#ifndef SQLITE_OMIT_DEPRECATED 4310SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4311SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4312SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4313SQLITE_DEPRECATED int sqlite3_global_recover(void); 4314SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4315SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4316 void*,sqlite3_int64); 4317#endif 4318 4319/* 4320** CAPI3REF: Obtaining SQL Values 4321** METHOD: sqlite3_value 4322** 4323** The C-language implementation of SQL functions and aggregates uses 4324** this set of interface routines to access the parameter values on 4325** the function or aggregate. 4326** 4327** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4328** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4329** define callbacks that implement the SQL functions and aggregates. 4330** The 3rd parameter to these callbacks is an array of pointers to 4331** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4332** each parameter to the SQL function. These routines are used to 4333** extract values from the [sqlite3_value] objects. 4334** 4335** These routines work only with [protected sqlite3_value] objects. 4336** Any attempt to use these routines on an [unprotected sqlite3_value] 4337** object results in undefined behavior. 4338** 4339** ^These routines work just like the corresponding [column access functions] 4340** except that these routines take a single [protected sqlite3_value] object 4341** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4342** 4343** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4344** in the native byte-order of the host machine. ^The 4345** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4346** extract UTF-16 strings as big-endian and little-endian respectively. 4347** 4348** ^(The sqlite3_value_numeric_type() interface attempts to apply 4349** numeric affinity to the value. This means that an attempt is 4350** made to convert the value to an integer or floating point. If 4351** such a conversion is possible without loss of information (in other 4352** words, if the value is a string that looks like a number) 4353** then the conversion is performed. Otherwise no conversion occurs. 4354** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4355** 4356** Please pay particular attention to the fact that the pointer returned 4357** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4358** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4359** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4360** or [sqlite3_value_text16()]. 4361** 4362** These routines must be called from the same thread as 4363** the SQL function that supplied the [sqlite3_value*] parameters. 4364*/ 4365const void *sqlite3_value_blob(sqlite3_value*); 4366int sqlite3_value_bytes(sqlite3_value*); 4367int sqlite3_value_bytes16(sqlite3_value*); 4368double sqlite3_value_double(sqlite3_value*); 4369int sqlite3_value_int(sqlite3_value*); 4370sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4371const unsigned char *sqlite3_value_text(sqlite3_value*); 4372const void *sqlite3_value_text16(sqlite3_value*); 4373const void *sqlite3_value_text16le(sqlite3_value*); 4374const void *sqlite3_value_text16be(sqlite3_value*); 4375int sqlite3_value_type(sqlite3_value*); 4376int sqlite3_value_numeric_type(sqlite3_value*); 4377 4378/* 4379** CAPI3REF: Finding The Subtype Of SQL Values 4380** METHOD: sqlite3_value 4381** 4382** The sqlite3_value_subtype(V) function returns the subtype for 4383** an [application-defined SQL function] argument V. The subtype 4384** information can be used to pass a limited amount of context from 4385** one SQL function to another. Use the [sqlite3_result_subtype()] 4386** routine to set the subtype for the return value of an SQL function. 4387** 4388** SQLite makes no use of subtype itself. It merely passes the subtype 4389** from the result of one [application-defined SQL function] into the 4390** input of another. 4391*/ 4392unsigned int sqlite3_value_subtype(sqlite3_value*); 4393 4394/* 4395** CAPI3REF: Copy And Free SQL Values 4396** METHOD: sqlite3_value 4397** 4398** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4399** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4400** is a [protected sqlite3_value] object even if the input is not. 4401** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4402** memory allocation fails. 4403** 4404** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4405** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4406** then sqlite3_value_free(V) is a harmless no-op. 4407*/ 4408sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4409void sqlite3_value_free(sqlite3_value*); 4410 4411/* 4412** CAPI3REF: Obtain Aggregate Function Context 4413** METHOD: sqlite3_context 4414** 4415** Implementations of aggregate SQL functions use this 4416** routine to allocate memory for storing their state. 4417** 4418** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4419** for a particular aggregate function, SQLite 4420** allocates N of memory, zeroes out that memory, and returns a pointer 4421** to the new memory. ^On second and subsequent calls to 4422** sqlite3_aggregate_context() for the same aggregate function instance, 4423** the same buffer is returned. Sqlite3_aggregate_context() is normally 4424** called once for each invocation of the xStep callback and then one 4425** last time when the xFinal callback is invoked. ^(When no rows match 4426** an aggregate query, the xStep() callback of the aggregate function 4427** implementation is never called and xFinal() is called exactly once. 4428** In those cases, sqlite3_aggregate_context() might be called for the 4429** first time from within xFinal().)^ 4430** 4431** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4432** when first called if N is less than or equal to zero or if a memory 4433** allocate error occurs. 4434** 4435** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4436** determined by the N parameter on first successful call. Changing the 4437** value of N in subsequent call to sqlite3_aggregate_context() within 4438** the same aggregate function instance will not resize the memory 4439** allocation.)^ Within the xFinal callback, it is customary to set 4440** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4441** pointless memory allocations occur. 4442** 4443** ^SQLite automatically frees the memory allocated by 4444** sqlite3_aggregate_context() when the aggregate query concludes. 4445** 4446** The first parameter must be a copy of the 4447** [sqlite3_context | SQL function context] that is the first parameter 4448** to the xStep or xFinal callback routine that implements the aggregate 4449** function. 4450** 4451** This routine must be called from the same thread in which 4452** the aggregate SQL function is running. 4453*/ 4454void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4455 4456/* 4457** CAPI3REF: User Data For Functions 4458** METHOD: sqlite3_context 4459** 4460** ^The sqlite3_user_data() interface returns a copy of 4461** the pointer that was the pUserData parameter (the 5th parameter) 4462** of the [sqlite3_create_function()] 4463** and [sqlite3_create_function16()] routines that originally 4464** registered the application defined function. 4465** 4466** This routine must be called from the same thread in which 4467** the application-defined function is running. 4468*/ 4469void *sqlite3_user_data(sqlite3_context*); 4470 4471/* 4472** CAPI3REF: Database Connection For Functions 4473** METHOD: sqlite3_context 4474** 4475** ^The sqlite3_context_db_handle() interface returns a copy of 4476** the pointer to the [database connection] (the 1st parameter) 4477** of the [sqlite3_create_function()] 4478** and [sqlite3_create_function16()] routines that originally 4479** registered the application defined function. 4480*/ 4481sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4482 4483/* 4484** CAPI3REF: Function Auxiliary Data 4485** METHOD: sqlite3_context 4486** 4487** These functions may be used by (non-aggregate) SQL functions to 4488** associate metadata with argument values. If the same value is passed to 4489** multiple invocations of the same SQL function during query execution, under 4490** some circumstances the associated metadata may be preserved. An example 4491** of where this might be useful is in a regular-expression matching 4492** function. The compiled version of the regular expression can be stored as 4493** metadata associated with the pattern string. 4494** Then as long as the pattern string remains the same, 4495** the compiled regular expression can be reused on multiple 4496** invocations of the same function. 4497** 4498** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4499** associated by the sqlite3_set_auxdata() function with the Nth argument 4500** value to the application-defined function. ^If there is no metadata 4501** associated with the function argument, this sqlite3_get_auxdata() interface 4502** returns a NULL pointer. 4503** 4504** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4505** argument of the application-defined function. ^Subsequent 4506** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4507** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4508** NULL if the metadata has been discarded. 4509** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4510** SQLite will invoke the destructor function X with parameter P exactly 4511** once, when the metadata is discarded. 4512** SQLite is free to discard the metadata at any time, including: <ul> 4513** <li> when the corresponding function parameter changes, or 4514** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4515** SQL statement, or 4516** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or 4517** <li> during the original sqlite3_set_auxdata() call when a memory 4518** allocation error occurs. </ul>)^ 4519** 4520** Note the last bullet in particular. The destructor X in 4521** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4522** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4523** should be called near the end of the function implementation and the 4524** function implementation should not make any use of P after 4525** sqlite3_set_auxdata() has been called. 4526** 4527** ^(In practice, metadata is preserved between function calls for 4528** function parameters that are compile-time constants, including literal 4529** values and [parameters] and expressions composed from the same.)^ 4530** 4531** These routines must be called from the same thread in which 4532** the SQL function is running. 4533*/ 4534void *sqlite3_get_auxdata(sqlite3_context*, int N); 4535void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4536 4537 4538/* 4539** CAPI3REF: Constants Defining Special Destructor Behavior 4540** 4541** These are special values for the destructor that is passed in as the 4542** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4543** argument is SQLITE_STATIC, it means that the content pointer is constant 4544** and will never change. It does not need to be destroyed. ^The 4545** SQLITE_TRANSIENT value means that the content will likely change in 4546** the near future and that SQLite should make its own private copy of 4547** the content before returning. 4548** 4549** The typedef is necessary to work around problems in certain 4550** C++ compilers. 4551*/ 4552typedef void (*sqlite3_destructor_type)(void*); 4553#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4554#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4555 4556/* 4557** CAPI3REF: Setting The Result Of An SQL Function 4558** METHOD: sqlite3_context 4559** 4560** These routines are used by the xFunc or xFinal callbacks that 4561** implement SQL functions and aggregates. See 4562** [sqlite3_create_function()] and [sqlite3_create_function16()] 4563** for additional information. 4564** 4565** These functions work very much like the [parameter binding] family of 4566** functions used to bind values to host parameters in prepared statements. 4567** Refer to the [SQL parameter] documentation for additional information. 4568** 4569** ^The sqlite3_result_blob() interface sets the result from 4570** an application-defined function to be the BLOB whose content is pointed 4571** to by the second parameter and which is N bytes long where N is the 4572** third parameter. 4573** 4574** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 4575** interfaces set the result of the application-defined function to be 4576** a BLOB containing all zero bytes and N bytes in size. 4577** 4578** ^The sqlite3_result_double() interface sets the result from 4579** an application-defined function to be a floating point value specified 4580** by its 2nd argument. 4581** 4582** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4583** cause the implemented SQL function to throw an exception. 4584** ^SQLite uses the string pointed to by the 4585** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4586** as the text of an error message. ^SQLite interprets the error 4587** message string from sqlite3_result_error() as UTF-8. ^SQLite 4588** interprets the string from sqlite3_result_error16() as UTF-16 in native 4589** byte order. ^If the third parameter to sqlite3_result_error() 4590** or sqlite3_result_error16() is negative then SQLite takes as the error 4591** message all text up through the first zero character. 4592** ^If the third parameter to sqlite3_result_error() or 4593** sqlite3_result_error16() is non-negative then SQLite takes that many 4594** bytes (not characters) from the 2nd parameter as the error message. 4595** ^The sqlite3_result_error() and sqlite3_result_error16() 4596** routines make a private copy of the error message text before 4597** they return. Hence, the calling function can deallocate or 4598** modify the text after they return without harm. 4599** ^The sqlite3_result_error_code() function changes the error code 4600** returned by SQLite as a result of an error in a function. ^By default, 4601** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4602** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4603** 4604** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4605** error indicating that a string or BLOB is too long to represent. 4606** 4607** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4608** error indicating that a memory allocation failed. 4609** 4610** ^The sqlite3_result_int() interface sets the return value 4611** of the application-defined function to be the 32-bit signed integer 4612** value given in the 2nd argument. 4613** ^The sqlite3_result_int64() interface sets the return value 4614** of the application-defined function to be the 64-bit signed integer 4615** value given in the 2nd argument. 4616** 4617** ^The sqlite3_result_null() interface sets the return value 4618** of the application-defined function to be NULL. 4619** 4620** ^The sqlite3_result_text(), sqlite3_result_text16(), 4621** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4622** set the return value of the application-defined function to be 4623** a text string which is represented as UTF-8, UTF-16 native byte order, 4624** UTF-16 little endian, or UTF-16 big endian, respectively. 4625** ^The sqlite3_result_text64() interface sets the return value of an 4626** application-defined function to be a text string in an encoding 4627** specified by the fifth (and last) parameter, which must be one 4628** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 4629** ^SQLite takes the text result from the application from 4630** the 2nd parameter of the sqlite3_result_text* interfaces. 4631** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4632** is negative, then SQLite takes result text from the 2nd parameter 4633** through the first zero character. 4634** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4635** is non-negative, then as many bytes (not characters) of the text 4636** pointed to by the 2nd parameter are taken as the application-defined 4637** function result. If the 3rd parameter is non-negative, then it 4638** must be the byte offset into the string where the NUL terminator would 4639** appear if the string where NUL terminated. If any NUL characters occur 4640** in the string at a byte offset that is less than the value of the 3rd 4641** parameter, then the resulting string will contain embedded NULs and the 4642** result of expressions operating on strings with embedded NULs is undefined. 4643** ^If the 4th parameter to the sqlite3_result_text* interfaces 4644** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4645** function as the destructor on the text or BLOB result when it has 4646** finished using that result. 4647** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4648** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4649** assumes that the text or BLOB result is in constant space and does not 4650** copy the content of the parameter nor call a destructor on the content 4651** when it has finished using that result. 4652** ^If the 4th parameter to the sqlite3_result_text* interfaces 4653** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4654** then SQLite makes a copy of the result into space obtained from 4655** from [sqlite3_malloc()] before it returns. 4656** 4657** ^The sqlite3_result_value() interface sets the result of 4658** the application-defined function to be a copy of the 4659** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4660** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4661** so that the [sqlite3_value] specified in the parameter may change or 4662** be deallocated after sqlite3_result_value() returns without harm. 4663** ^A [protected sqlite3_value] object may always be used where an 4664** [unprotected sqlite3_value] object is required, so either 4665** kind of [sqlite3_value] object can be used with this interface. 4666** 4667** If these routines are called from within the different thread 4668** than the one containing the application-defined function that received 4669** the [sqlite3_context] pointer, the results are undefined. 4670*/ 4671void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4672void sqlite3_result_blob64(sqlite3_context*,const void*, 4673 sqlite3_uint64,void(*)(void*)); 4674void sqlite3_result_double(sqlite3_context*, double); 4675void sqlite3_result_error(sqlite3_context*, const char*, int); 4676void sqlite3_result_error16(sqlite3_context*, const void*, int); 4677void sqlite3_result_error_toobig(sqlite3_context*); 4678void sqlite3_result_error_nomem(sqlite3_context*); 4679void sqlite3_result_error_code(sqlite3_context*, int); 4680void sqlite3_result_int(sqlite3_context*, int); 4681void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4682void sqlite3_result_null(sqlite3_context*); 4683void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4684void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 4685 void(*)(void*), unsigned char encoding); 4686void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4687void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4688void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4689void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4690void sqlite3_result_zeroblob(sqlite3_context*, int n); 4691int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 4692 4693 4694/* 4695** CAPI3REF: Setting The Subtype Of An SQL Function 4696** METHOD: sqlite3_context 4697** 4698** The sqlite3_result_subtype(C,T) function causes the subtype of 4699** the result from the [application-defined SQL function] with 4700** [sqlite3_context] C to be the value T. Only the lower 8 bits 4701** of the subtype T are preserved in current versions of SQLite; 4702** higher order bits are discarded. 4703** The number of subtype bytes preserved by SQLite might increase 4704** in future releases of SQLite. 4705*/ 4706void sqlite3_result_subtype(sqlite3_context*,unsigned int); 4707 4708/* 4709** CAPI3REF: Define New Collating Sequences 4710** METHOD: sqlite3 4711** 4712** ^These functions add, remove, or modify a [collation] associated 4713** with the [database connection] specified as the first argument. 4714** 4715** ^The name of the collation is a UTF-8 string 4716** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4717** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4718** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4719** considered to be the same name. 4720** 4721** ^(The third argument (eTextRep) must be one of the constants: 4722** <ul> 4723** <li> [SQLITE_UTF8], 4724** <li> [SQLITE_UTF16LE], 4725** <li> [SQLITE_UTF16BE], 4726** <li> [SQLITE_UTF16], or 4727** <li> [SQLITE_UTF16_ALIGNED]. 4728** </ul>)^ 4729** ^The eTextRep argument determines the encoding of strings passed 4730** to the collating function callback, xCallback. 4731** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4732** force strings to be UTF16 with native byte order. 4733** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4734** on an even byte address. 4735** 4736** ^The fourth argument, pArg, is an application data pointer that is passed 4737** through as the first argument to the collating function callback. 4738** 4739** ^The fifth argument, xCallback, is a pointer to the collating function. 4740** ^Multiple collating functions can be registered using the same name but 4741** with different eTextRep parameters and SQLite will use whichever 4742** function requires the least amount of data transformation. 4743** ^If the xCallback argument is NULL then the collating function is 4744** deleted. ^When all collating functions having the same name are deleted, 4745** that collation is no longer usable. 4746** 4747** ^The collating function callback is invoked with a copy of the pArg 4748** application data pointer and with two strings in the encoding specified 4749** by the eTextRep argument. The collating function must return an 4750** integer that is negative, zero, or positive 4751** if the first string is less than, equal to, or greater than the second, 4752** respectively. A collating function must always return the same answer 4753** given the same inputs. If two or more collating functions are registered 4754** to the same collation name (using different eTextRep values) then all 4755** must give an equivalent answer when invoked with equivalent strings. 4756** The collating function must obey the following properties for all 4757** strings A, B, and C: 4758** 4759** <ol> 4760** <li> If A==B then B==A. 4761** <li> If A==B and B==C then A==C. 4762** <li> If A<B THEN B>A. 4763** <li> If A<B and B<C then A<C. 4764** </ol> 4765** 4766** If a collating function fails any of the above constraints and that 4767** collating function is registered and used, then the behavior of SQLite 4768** is undefined. 4769** 4770** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4771** with the addition that the xDestroy callback is invoked on pArg when 4772** the collating function is deleted. 4773** ^Collating functions are deleted when they are overridden by later 4774** calls to the collation creation functions or when the 4775** [database connection] is closed using [sqlite3_close()]. 4776** 4777** ^The xDestroy callback is <u>not</u> called if the 4778** sqlite3_create_collation_v2() function fails. Applications that invoke 4779** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4780** check the return code and dispose of the application data pointer 4781** themselves rather than expecting SQLite to deal with it for them. 4782** This is different from every other SQLite interface. The inconsistency 4783** is unfortunate but cannot be changed without breaking backwards 4784** compatibility. 4785** 4786** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4787*/ 4788int sqlite3_create_collation( 4789 sqlite3*, 4790 const char *zName, 4791 int eTextRep, 4792 void *pArg, 4793 int(*xCompare)(void*,int,const void*,int,const void*) 4794); 4795int sqlite3_create_collation_v2( 4796 sqlite3*, 4797 const char *zName, 4798 int eTextRep, 4799 void *pArg, 4800 int(*xCompare)(void*,int,const void*,int,const void*), 4801 void(*xDestroy)(void*) 4802); 4803int sqlite3_create_collation16( 4804 sqlite3*, 4805 const void *zName, 4806 int eTextRep, 4807 void *pArg, 4808 int(*xCompare)(void*,int,const void*,int,const void*) 4809); 4810 4811/* 4812** CAPI3REF: Collation Needed Callbacks 4813** METHOD: sqlite3 4814** 4815** ^To avoid having to register all collation sequences before a database 4816** can be used, a single callback function may be registered with the 4817** [database connection] to be invoked whenever an undefined collation 4818** sequence is required. 4819** 4820** ^If the function is registered using the sqlite3_collation_needed() API, 4821** then it is passed the names of undefined collation sequences as strings 4822** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4823** the names are passed as UTF-16 in machine native byte order. 4824** ^A call to either function replaces the existing collation-needed callback. 4825** 4826** ^(When the callback is invoked, the first argument passed is a copy 4827** of the second argument to sqlite3_collation_needed() or 4828** sqlite3_collation_needed16(). The second argument is the database 4829** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4830** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4831** sequence function required. The fourth parameter is the name of the 4832** required collation sequence.)^ 4833** 4834** The callback function should register the desired collation using 4835** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4836** [sqlite3_create_collation_v2()]. 4837*/ 4838int sqlite3_collation_needed( 4839 sqlite3*, 4840 void*, 4841 void(*)(void*,sqlite3*,int eTextRep,const char*) 4842); 4843int sqlite3_collation_needed16( 4844 sqlite3*, 4845 void*, 4846 void(*)(void*,sqlite3*,int eTextRep,const void*) 4847); 4848 4849#ifdef SQLITE_HAS_CODEC 4850/* 4851** Specify the key for an encrypted database. This routine should be 4852** called right after sqlite3_open(). 4853** 4854** The code to implement this API is not available in the public release 4855** of SQLite. 4856*/ 4857int sqlite3_key( 4858 sqlite3 *db, /* Database to be rekeyed */ 4859 const void *pKey, int nKey /* The key */ 4860); 4861int sqlite3_key_v2( 4862 sqlite3 *db, /* Database to be rekeyed */ 4863 const char *zDbName, /* Name of the database */ 4864 const void *pKey, int nKey /* The key */ 4865); 4866 4867/* 4868** Change the key on an open database. If the current database is not 4869** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4870** database is decrypted. 4871** 4872** The code to implement this API is not available in the public release 4873** of SQLite. 4874*/ 4875int sqlite3_rekey( 4876 sqlite3 *db, /* Database to be rekeyed */ 4877 const void *pKey, int nKey /* The new key */ 4878); 4879int sqlite3_rekey_v2( 4880 sqlite3 *db, /* Database to be rekeyed */ 4881 const char *zDbName, /* Name of the database */ 4882 const void *pKey, int nKey /* The new key */ 4883); 4884 4885/* 4886** Specify the activation key for a SEE database. Unless 4887** activated, none of the SEE routines will work. 4888*/ 4889void sqlite3_activate_see( 4890 const char *zPassPhrase /* Activation phrase */ 4891); 4892#endif 4893 4894#ifdef SQLITE_ENABLE_CEROD 4895/* 4896** Specify the activation key for a CEROD database. Unless 4897** activated, none of the CEROD routines will work. 4898*/ 4899void sqlite3_activate_cerod( 4900 const char *zPassPhrase /* Activation phrase */ 4901); 4902#endif 4903 4904/* 4905** CAPI3REF: Suspend Execution For A Short Time 4906** 4907** The sqlite3_sleep() function causes the current thread to suspend execution 4908** for at least a number of milliseconds specified in its parameter. 4909** 4910** If the operating system does not support sleep requests with 4911** millisecond time resolution, then the time will be rounded up to 4912** the nearest second. The number of milliseconds of sleep actually 4913** requested from the operating system is returned. 4914** 4915** ^SQLite implements this interface by calling the xSleep() 4916** method of the default [sqlite3_vfs] object. If the xSleep() method 4917** of the default VFS is not implemented correctly, or not implemented at 4918** all, then the behavior of sqlite3_sleep() may deviate from the description 4919** in the previous paragraphs. 4920*/ 4921int sqlite3_sleep(int); 4922 4923/* 4924** CAPI3REF: Name Of The Folder Holding Temporary Files 4925** 4926** ^(If this global variable is made to point to a string which is 4927** the name of a folder (a.k.a. directory), then all temporary files 4928** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4929** will be placed in that directory.)^ ^If this variable 4930** is a NULL pointer, then SQLite performs a search for an appropriate 4931** temporary file directory. 4932** 4933** Applications are strongly discouraged from using this global variable. 4934** It is required to set a temporary folder on Windows Runtime (WinRT). 4935** But for all other platforms, it is highly recommended that applications 4936** neither read nor write this variable. This global variable is a relic 4937** that exists for backwards compatibility of legacy applications and should 4938** be avoided in new projects. 4939** 4940** It is not safe to read or modify this variable in more than one 4941** thread at a time. It is not safe to read or modify this variable 4942** if a [database connection] is being used at the same time in a separate 4943** thread. 4944** It is intended that this variable be set once 4945** as part of process initialization and before any SQLite interface 4946** routines have been called and that this variable remain unchanged 4947** thereafter. 4948** 4949** ^The [temp_store_directory pragma] may modify this variable and cause 4950** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4951** the [temp_store_directory pragma] always assumes that any string 4952** that this variable points to is held in memory obtained from 4953** [sqlite3_malloc] and the pragma may attempt to free that memory 4954** using [sqlite3_free]. 4955** Hence, if this variable is modified directly, either it should be 4956** made NULL or made to point to memory obtained from [sqlite3_malloc] 4957** or else the use of the [temp_store_directory pragma] should be avoided. 4958** Except when requested by the [temp_store_directory pragma], SQLite 4959** does not free the memory that sqlite3_temp_directory points to. If 4960** the application wants that memory to be freed, it must do 4961** so itself, taking care to only do so after all [database connection] 4962** objects have been destroyed. 4963** 4964** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4965** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4966** features that require the use of temporary files may fail. Here is an 4967** example of how to do this using C++ with the Windows Runtime: 4968** 4969** <blockquote><pre> 4970** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4971** TemporaryFolder->Path->Data(); 4972** char zPathBuf[MAX_PATH + 1]; 4973** memset(zPathBuf, 0, sizeof(zPathBuf)); 4974** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4975** NULL, NULL); 4976** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4977** </pre></blockquote> 4978*/ 4979SQLITE_EXTERN char *sqlite3_temp_directory; 4980 4981/* 4982** CAPI3REF: Name Of The Folder Holding Database Files 4983** 4984** ^(If this global variable is made to point to a string which is 4985** the name of a folder (a.k.a. directory), then all database files 4986** specified with a relative pathname and created or accessed by 4987** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4988** to be relative to that directory.)^ ^If this variable is a NULL 4989** pointer, then SQLite assumes that all database files specified 4990** with a relative pathname are relative to the current directory 4991** for the process. Only the windows VFS makes use of this global 4992** variable; it is ignored by the unix VFS. 4993** 4994** Changing the value of this variable while a database connection is 4995** open can result in a corrupt database. 4996** 4997** It is not safe to read or modify this variable in more than one 4998** thread at a time. It is not safe to read or modify this variable 4999** if a [database connection] is being used at the same time in a separate 5000** thread. 5001** It is intended that this variable be set once 5002** as part of process initialization and before any SQLite interface 5003** routines have been called and that this variable remain unchanged 5004** thereafter. 5005** 5006** ^The [data_store_directory pragma] may modify this variable and cause 5007** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5008** the [data_store_directory pragma] always assumes that any string 5009** that this variable points to is held in memory obtained from 5010** [sqlite3_malloc] and the pragma may attempt to free that memory 5011** using [sqlite3_free]. 5012** Hence, if this variable is modified directly, either it should be 5013** made NULL or made to point to memory obtained from [sqlite3_malloc] 5014** or else the use of the [data_store_directory pragma] should be avoided. 5015*/ 5016SQLITE_EXTERN char *sqlite3_data_directory; 5017 5018/* 5019** CAPI3REF: Test For Auto-Commit Mode 5020** KEYWORDS: {autocommit mode} 5021** METHOD: sqlite3 5022** 5023** ^The sqlite3_get_autocommit() interface returns non-zero or 5024** zero if the given database connection is or is not in autocommit mode, 5025** respectively. ^Autocommit mode is on by default. 5026** ^Autocommit mode is disabled by a [BEGIN] statement. 5027** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5028** 5029** If certain kinds of errors occur on a statement within a multi-statement 5030** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5031** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5032** transaction might be rolled back automatically. The only way to 5033** find out whether SQLite automatically rolled back the transaction after 5034** an error is to use this function. 5035** 5036** If another thread changes the autocommit status of the database 5037** connection while this routine is running, then the return value 5038** is undefined. 5039*/ 5040int sqlite3_get_autocommit(sqlite3*); 5041 5042/* 5043** CAPI3REF: Find The Database Handle Of A Prepared Statement 5044** METHOD: sqlite3_stmt 5045** 5046** ^The sqlite3_db_handle interface returns the [database connection] handle 5047** to which a [prepared statement] belongs. ^The [database connection] 5048** returned by sqlite3_db_handle is the same [database connection] 5049** that was the first argument 5050** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5051** create the statement in the first place. 5052*/ 5053sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5054 5055/* 5056** CAPI3REF: Return The Filename For A Database Connection 5057** METHOD: sqlite3 5058** 5059** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5060** associated with database N of connection D. ^The main database file 5061** has the name "main". If there is no attached database N on the database 5062** connection D, or if database N is a temporary or in-memory database, then 5063** a NULL pointer is returned. 5064** 5065** ^The filename returned by this function is the output of the 5066** xFullPathname method of the [VFS]. ^In other words, the filename 5067** will be an absolute pathname, even if the filename used 5068** to open the database originally was a URI or relative pathname. 5069*/ 5070const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5071 5072/* 5073** CAPI3REF: Determine if a database is read-only 5074** METHOD: sqlite3 5075** 5076** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5077** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5078** the name of a database on connection D. 5079*/ 5080int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5081 5082/* 5083** CAPI3REF: Find the next prepared statement 5084** METHOD: sqlite3 5085** 5086** ^This interface returns a pointer to the next [prepared statement] after 5087** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5088** then this interface returns a pointer to the first prepared statement 5089** associated with the database connection pDb. ^If no prepared statement 5090** satisfies the conditions of this routine, it returns NULL. 5091** 5092** The [database connection] pointer D in a call to 5093** [sqlite3_next_stmt(D,S)] must refer to an open database 5094** connection and in particular must not be a NULL pointer. 5095*/ 5096sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5097 5098/* 5099** CAPI3REF: Commit And Rollback Notification Callbacks 5100** METHOD: sqlite3 5101** 5102** ^The sqlite3_commit_hook() interface registers a callback 5103** function to be invoked whenever a transaction is [COMMIT | committed]. 5104** ^Any callback set by a previous call to sqlite3_commit_hook() 5105** for the same database connection is overridden. 5106** ^The sqlite3_rollback_hook() interface registers a callback 5107** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5108** ^Any callback set by a previous call to sqlite3_rollback_hook() 5109** for the same database connection is overridden. 5110** ^The pArg argument is passed through to the callback. 5111** ^If the callback on a commit hook function returns non-zero, 5112** then the commit is converted into a rollback. 5113** 5114** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5115** return the P argument from the previous call of the same function 5116** on the same [database connection] D, or NULL for 5117** the first call for each function on D. 5118** 5119** The commit and rollback hook callbacks are not reentrant. 5120** The callback implementation must not do anything that will modify 5121** the database connection that invoked the callback. Any actions 5122** to modify the database connection must be deferred until after the 5123** completion of the [sqlite3_step()] call that triggered the commit 5124** or rollback hook in the first place. 5125** Note that running any other SQL statements, including SELECT statements, 5126** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5127** the database connections for the meaning of "modify" in this paragraph. 5128** 5129** ^Registering a NULL function disables the callback. 5130** 5131** ^When the commit hook callback routine returns zero, the [COMMIT] 5132** operation is allowed to continue normally. ^If the commit hook 5133** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5134** ^The rollback hook is invoked on a rollback that results from a commit 5135** hook returning non-zero, just as it would be with any other rollback. 5136** 5137** ^For the purposes of this API, a transaction is said to have been 5138** rolled back if an explicit "ROLLBACK" statement is executed, or 5139** an error or constraint causes an implicit rollback to occur. 5140** ^The rollback callback is not invoked if a transaction is 5141** automatically rolled back because the database connection is closed. 5142** 5143** See also the [sqlite3_update_hook()] interface. 5144*/ 5145void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5146void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5147 5148/* 5149** CAPI3REF: Data Change Notification Callbacks 5150** METHOD: sqlite3 5151** 5152** ^The sqlite3_update_hook() interface registers a callback function 5153** with the [database connection] identified by the first argument 5154** to be invoked whenever a row is updated, inserted or deleted in 5155** a rowid table. 5156** ^Any callback set by a previous call to this function 5157** for the same database connection is overridden. 5158** 5159** ^The second argument is a pointer to the function to invoke when a 5160** row is updated, inserted or deleted in a rowid table. 5161** ^The first argument to the callback is a copy of the third argument 5162** to sqlite3_update_hook(). 5163** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5164** or [SQLITE_UPDATE], depending on the operation that caused the callback 5165** to be invoked. 5166** ^The third and fourth arguments to the callback contain pointers to the 5167** database and table name containing the affected row. 5168** ^The final callback parameter is the [rowid] of the row. 5169** ^In the case of an update, this is the [rowid] after the update takes place. 5170** 5171** ^(The update hook is not invoked when internal system tables are 5172** modified (i.e. sqlite_master and sqlite_sequence).)^ 5173** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5174** 5175** ^In the current implementation, the update hook 5176** is not invoked when duplication rows are deleted because of an 5177** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5178** invoked when rows are deleted using the [truncate optimization]. 5179** The exceptions defined in this paragraph might change in a future 5180** release of SQLite. 5181** 5182** The update hook implementation must not do anything that will modify 5183** the database connection that invoked the update hook. Any actions 5184** to modify the database connection must be deferred until after the 5185** completion of the [sqlite3_step()] call that triggered the update hook. 5186** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5187** database connections for the meaning of "modify" in this paragraph. 5188** 5189** ^The sqlite3_update_hook(D,C,P) function 5190** returns the P argument from the previous call 5191** on the same [database connection] D, or NULL for 5192** the first call on D. 5193** 5194** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 5195** interfaces. 5196*/ 5197void *sqlite3_update_hook( 5198 sqlite3*, 5199 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5200 void* 5201); 5202 5203/* 5204** CAPI3REF: Enable Or Disable Shared Pager Cache 5205** 5206** ^(This routine enables or disables the sharing of the database cache 5207** and schema data structures between [database connection | connections] 5208** to the same database. Sharing is enabled if the argument is true 5209** and disabled if the argument is false.)^ 5210** 5211** ^Cache sharing is enabled and disabled for an entire process. 5212** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 5213** sharing was enabled or disabled for each thread separately. 5214** 5215** ^(The cache sharing mode set by this interface effects all subsequent 5216** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5217** Existing database connections continue use the sharing mode 5218** that was in effect at the time they were opened.)^ 5219** 5220** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5221** successfully. An [error code] is returned otherwise.)^ 5222** 5223** ^Shared cache is disabled by default. But this might change in 5224** future releases of SQLite. Applications that care about shared 5225** cache setting should set it explicitly. 5226** 5227** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5228** and will always return SQLITE_MISUSE. On those systems, 5229** shared cache mode should be enabled per-database connection via 5230** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5231** 5232** This interface is threadsafe on processors where writing a 5233** 32-bit integer is atomic. 5234** 5235** See Also: [SQLite Shared-Cache Mode] 5236*/ 5237int sqlite3_enable_shared_cache(int); 5238 5239/* 5240** CAPI3REF: Attempt To Free Heap Memory 5241** 5242** ^The sqlite3_release_memory() interface attempts to free N bytes 5243** of heap memory by deallocating non-essential memory allocations 5244** held by the database library. Memory used to cache database 5245** pages to improve performance is an example of non-essential memory. 5246** ^sqlite3_release_memory() returns the number of bytes actually freed, 5247** which might be more or less than the amount requested. 5248** ^The sqlite3_release_memory() routine is a no-op returning zero 5249** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5250** 5251** See also: [sqlite3_db_release_memory()] 5252*/ 5253int sqlite3_release_memory(int); 5254 5255/* 5256** CAPI3REF: Free Memory Used By A Database Connection 5257** METHOD: sqlite3 5258** 5259** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5260** memory as possible from database connection D. Unlike the 5261** [sqlite3_release_memory()] interface, this interface is in effect even 5262** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5263** omitted. 5264** 5265** See also: [sqlite3_release_memory()] 5266*/ 5267int sqlite3_db_release_memory(sqlite3*); 5268 5269/* 5270** CAPI3REF: Impose A Limit On Heap Size 5271** 5272** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5273** soft limit on the amount of heap memory that may be allocated by SQLite. 5274** ^SQLite strives to keep heap memory utilization below the soft heap 5275** limit by reducing the number of pages held in the page cache 5276** as heap memory usages approaches the limit. 5277** ^The soft heap limit is "soft" because even though SQLite strives to stay 5278** below the limit, it will exceed the limit rather than generate 5279** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5280** is advisory only. 5281** 5282** ^The return value from sqlite3_soft_heap_limit64() is the size of 5283** the soft heap limit prior to the call, or negative in the case of an 5284** error. ^If the argument N is negative 5285** then no change is made to the soft heap limit. Hence, the current 5286** size of the soft heap limit can be determined by invoking 5287** sqlite3_soft_heap_limit64() with a negative argument. 5288** 5289** ^If the argument N is zero then the soft heap limit is disabled. 5290** 5291** ^(The soft heap limit is not enforced in the current implementation 5292** if one or more of following conditions are true: 5293** 5294** <ul> 5295** <li> The soft heap limit is set to zero. 5296** <li> Memory accounting is disabled using a combination of the 5297** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5298** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5299** <li> An alternative page cache implementation is specified using 5300** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5301** <li> The page cache allocates from its own memory pool supplied 5302** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5303** from the heap. 5304** </ul>)^ 5305** 5306** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 5307** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5308** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5309** the soft heap limit is enforced on every memory allocation. Without 5310** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5311** when memory is allocated by the page cache. Testing suggests that because 5312** the page cache is the predominate memory user in SQLite, most 5313** applications will achieve adequate soft heap limit enforcement without 5314** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5315** 5316** The circumstances under which SQLite will enforce the soft heap limit may 5317** changes in future releases of SQLite. 5318*/ 5319sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5320 5321/* 5322** CAPI3REF: Deprecated Soft Heap Limit Interface 5323** DEPRECATED 5324** 5325** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5326** interface. This routine is provided for historical compatibility 5327** only. All new applications should use the 5328** [sqlite3_soft_heap_limit64()] interface rather than this one. 5329*/ 5330SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5331 5332 5333/* 5334** CAPI3REF: Extract Metadata About A Column Of A Table 5335** METHOD: sqlite3 5336** 5337** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5338** information about column C of table T in database D 5339** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5340** interface returns SQLITE_OK and fills in the non-NULL pointers in 5341** the final five arguments with appropriate values if the specified 5342** column exists. ^The sqlite3_table_column_metadata() interface returns 5343** SQLITE_ERROR and if the specified column does not exist. 5344** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5345** NULL pointer, then this routine simply checks for the existance of the 5346** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5347** does not. 5348** 5349** ^The column is identified by the second, third and fourth parameters to 5350** this function. ^(The second parameter is either the name of the database 5351** (i.e. "main", "temp", or an attached database) containing the specified 5352** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5353** for the table using the same algorithm used by the database engine to 5354** resolve unqualified table references. 5355** 5356** ^The third and fourth parameters to this function are the table and column 5357** name of the desired column, respectively. 5358** 5359** ^Metadata is returned by writing to the memory locations passed as the 5th 5360** and subsequent parameters to this function. ^Any of these arguments may be 5361** NULL, in which case the corresponding element of metadata is omitted. 5362** 5363** ^(<blockquote> 5364** <table border="1"> 5365** <tr><th> Parameter <th> Output<br>Type <th> Description 5366** 5367** <tr><td> 5th <td> const char* <td> Data type 5368** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5369** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5370** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5371** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5372** </table> 5373** </blockquote>)^ 5374** 5375** ^The memory pointed to by the character pointers returned for the 5376** declaration type and collation sequence is valid until the next 5377** call to any SQLite API function. 5378** 5379** ^If the specified table is actually a view, an [error code] is returned. 5380** 5381** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5382** is not a [WITHOUT ROWID] table and an 5383** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5384** parameters are set for the explicitly declared column. ^(If there is no 5385** [INTEGER PRIMARY KEY] column, then the outputs 5386** for the [rowid] are set as follows: 5387** 5388** <pre> 5389** data type: "INTEGER" 5390** collation sequence: "BINARY" 5391** not null: 0 5392** primary key: 1 5393** auto increment: 0 5394** </pre>)^ 5395** 5396** ^This function causes all database schemas to be read from disk and 5397** parsed, if that has not already been done, and returns an error if 5398** any errors are encountered while loading the schema. 5399*/ 5400int sqlite3_table_column_metadata( 5401 sqlite3 *db, /* Connection handle */ 5402 const char *zDbName, /* Database name or NULL */ 5403 const char *zTableName, /* Table name */ 5404 const char *zColumnName, /* Column name */ 5405 char const **pzDataType, /* OUTPUT: Declared data type */ 5406 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5407 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5408 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5409 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5410); 5411 5412/* 5413** CAPI3REF: Load An Extension 5414** METHOD: sqlite3 5415** 5416** ^This interface loads an SQLite extension library from the named file. 5417** 5418** ^The sqlite3_load_extension() interface attempts to load an 5419** [SQLite extension] library contained in the file zFile. If 5420** the file cannot be loaded directly, attempts are made to load 5421** with various operating-system specific extensions added. 5422** So for example, if "samplelib" cannot be loaded, then names like 5423** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5424** be tried also. 5425** 5426** ^The entry point is zProc. 5427** ^(zProc may be 0, in which case SQLite will try to come up with an 5428** entry point name on its own. It first tries "sqlite3_extension_init". 5429** If that does not work, it constructs a name "sqlite3_X_init" where the 5430** X is consists of the lower-case equivalent of all ASCII alphabetic 5431** characters in the filename from the last "/" to the first following 5432** "." and omitting any initial "lib".)^ 5433** ^The sqlite3_load_extension() interface returns 5434** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5435** ^If an error occurs and pzErrMsg is not 0, then the 5436** [sqlite3_load_extension()] interface shall attempt to 5437** fill *pzErrMsg with error message text stored in memory 5438** obtained from [sqlite3_malloc()]. The calling function 5439** should free this memory by calling [sqlite3_free()]. 5440** 5441** ^Extension loading must be enabled using 5442** [sqlite3_enable_load_extension()] prior to calling this API, 5443** otherwise an error will be returned. 5444** 5445** See also the [load_extension() SQL function]. 5446*/ 5447int sqlite3_load_extension( 5448 sqlite3 *db, /* Load the extension into this database connection */ 5449 const char *zFile, /* Name of the shared library containing extension */ 5450 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5451 char **pzErrMsg /* Put error message here if not 0 */ 5452); 5453 5454/* 5455** CAPI3REF: Enable Or Disable Extension Loading 5456** METHOD: sqlite3 5457** 5458** ^So as not to open security holes in older applications that are 5459** unprepared to deal with [extension loading], and as a means of disabling 5460** [extension loading] while evaluating user-entered SQL, the following API 5461** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5462** 5463** ^Extension loading is off by default. 5464** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5465** to turn extension loading on and call it with onoff==0 to turn 5466** it back off again. 5467*/ 5468int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5469 5470/* 5471** CAPI3REF: Automatically Load Statically Linked Extensions 5472** 5473** ^This interface causes the xEntryPoint() function to be invoked for 5474** each new [database connection] that is created. The idea here is that 5475** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5476** that is to be automatically loaded into all new database connections. 5477** 5478** ^(Even though the function prototype shows that xEntryPoint() takes 5479** no arguments and returns void, SQLite invokes xEntryPoint() with three 5480** arguments and expects and integer result as if the signature of the 5481** entry point where as follows: 5482** 5483** <blockquote><pre> 5484** int xEntryPoint( 5485** sqlite3 *db, 5486** const char **pzErrMsg, 5487** const struct sqlite3_api_routines *pThunk 5488** ); 5489** </pre></blockquote>)^ 5490** 5491** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5492** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5493** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5494** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5495** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5496** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5497** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5498** 5499** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5500** on the list of automatic extensions is a harmless no-op. ^No entry point 5501** will be called more than once for each database connection that is opened. 5502** 5503** See also: [sqlite3_reset_auto_extension()] 5504** and [sqlite3_cancel_auto_extension()] 5505*/ 5506int sqlite3_auto_extension(void (*xEntryPoint)(void)); 5507 5508/* 5509** CAPI3REF: Cancel Automatic Extension Loading 5510** 5511** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5512** initialization routine X that was registered using a prior call to 5513** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5514** routine returns 1 if initialization routine X was successfully 5515** unregistered and it returns 0 if X was not on the list of initialization 5516** routines. 5517*/ 5518int sqlite3_cancel_auto_extension(void (*xEntryPoint)(void)); 5519 5520/* 5521** CAPI3REF: Reset Automatic Extension Loading 5522** 5523** ^This interface disables all automatic extensions previously 5524** registered using [sqlite3_auto_extension()]. 5525*/ 5526void sqlite3_reset_auto_extension(void); 5527 5528/* 5529** The interface to the virtual-table mechanism is currently considered 5530** to be experimental. The interface might change in incompatible ways. 5531** If this is a problem for you, do not use the interface at this time. 5532** 5533** When the virtual-table mechanism stabilizes, we will declare the 5534** interface fixed, support it indefinitely, and remove this comment. 5535*/ 5536 5537/* 5538** Structures used by the virtual table interface 5539*/ 5540typedef struct sqlite3_vtab sqlite3_vtab; 5541typedef struct sqlite3_index_info sqlite3_index_info; 5542typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5543typedef struct sqlite3_module sqlite3_module; 5544 5545/* 5546** CAPI3REF: Virtual Table Object 5547** KEYWORDS: sqlite3_module {virtual table module} 5548** 5549** This structure, sometimes called a "virtual table module", 5550** defines the implementation of a [virtual tables]. 5551** This structure consists mostly of methods for the module. 5552** 5553** ^A virtual table module is created by filling in a persistent 5554** instance of this structure and passing a pointer to that instance 5555** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5556** ^The registration remains valid until it is replaced by a different 5557** module or until the [database connection] closes. The content 5558** of this structure must not change while it is registered with 5559** any database connection. 5560*/ 5561struct sqlite3_module { 5562 int iVersion; 5563 int (*xCreate)(sqlite3*, void *pAux, 5564 int argc, const char *const*argv, 5565 sqlite3_vtab **ppVTab, char**); 5566 int (*xConnect)(sqlite3*, void *pAux, 5567 int argc, const char *const*argv, 5568 sqlite3_vtab **ppVTab, char**); 5569 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5570 int (*xDisconnect)(sqlite3_vtab *pVTab); 5571 int (*xDestroy)(sqlite3_vtab *pVTab); 5572 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5573 int (*xClose)(sqlite3_vtab_cursor*); 5574 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5575 int argc, sqlite3_value **argv); 5576 int (*xNext)(sqlite3_vtab_cursor*); 5577 int (*xEof)(sqlite3_vtab_cursor*); 5578 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5579 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5580 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5581 int (*xBegin)(sqlite3_vtab *pVTab); 5582 int (*xSync)(sqlite3_vtab *pVTab); 5583 int (*xCommit)(sqlite3_vtab *pVTab); 5584 int (*xRollback)(sqlite3_vtab *pVTab); 5585 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5586 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5587 void **ppArg); 5588 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5589 /* The methods above are in version 1 of the sqlite_module object. Those 5590 ** below are for version 2 and greater. */ 5591 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5592 int (*xRelease)(sqlite3_vtab *pVTab, int); 5593 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5594}; 5595 5596/* 5597** CAPI3REF: Virtual Table Indexing Information 5598** KEYWORDS: sqlite3_index_info 5599** 5600** The sqlite3_index_info structure and its substructures is used as part 5601** of the [virtual table] interface to 5602** pass information into and receive the reply from the [xBestIndex] 5603** method of a [virtual table module]. The fields under **Inputs** are the 5604** inputs to xBestIndex and are read-only. xBestIndex inserts its 5605** results into the **Outputs** fields. 5606** 5607** ^(The aConstraint[] array records WHERE clause constraints of the form: 5608** 5609** <blockquote>column OP expr</blockquote> 5610** 5611** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5612** stored in aConstraint[].op using one of the 5613** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5614** ^(The index of the column is stored in 5615** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5616** expr on the right-hand side can be evaluated (and thus the constraint 5617** is usable) and false if it cannot.)^ 5618** 5619** ^The optimizer automatically inverts terms of the form "expr OP column" 5620** and makes other simplifications to the WHERE clause in an attempt to 5621** get as many WHERE clause terms into the form shown above as possible. 5622** ^The aConstraint[] array only reports WHERE clause terms that are 5623** relevant to the particular virtual table being queried. 5624** 5625** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5626** ^Each term of aOrderBy records a column of the ORDER BY clause. 5627** 5628** The colUsed field indicates which columns of the virtual table may be 5629** required by the current scan. Virtual table columns are numbered from 5630** zero in the order in which they appear within the CREATE TABLE statement 5631** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 5632** the corresponding bit is set within the colUsed mask if the column may be 5633** required by SQLite. If the table has at least 64 columns and any column 5634** to the right of the first 63 is required, then bit 63 of colUsed is also 5635** set. In other words, column iCol may be required if the expression 5636** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 5637** non-zero. 5638** 5639** The [xBestIndex] method must fill aConstraintUsage[] with information 5640** about what parameters to pass to xFilter. ^If argvIndex>0 then 5641** the right-hand side of the corresponding aConstraint[] is evaluated 5642** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5643** is true, then the constraint is assumed to be fully handled by the 5644** virtual table and is not checked again by SQLite.)^ 5645** 5646** ^The idxNum and idxPtr values are recorded and passed into the 5647** [xFilter] method. 5648** ^[sqlite3_free()] is used to free idxPtr if and only if 5649** needToFreeIdxPtr is true. 5650** 5651** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5652** the correct order to satisfy the ORDER BY clause so that no separate 5653** sorting step is required. 5654** 5655** ^The estimatedCost value is an estimate of the cost of a particular 5656** strategy. A cost of N indicates that the cost of the strategy is similar 5657** to a linear scan of an SQLite table with N rows. A cost of log(N) 5658** indicates that the expense of the operation is similar to that of a 5659** binary search on a unique indexed field of an SQLite table with N rows. 5660** 5661** ^The estimatedRows value is an estimate of the number of rows that 5662** will be returned by the strategy. 5663** 5664** The xBestIndex method may optionally populate the idxFlags field with a 5665** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 5666** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 5667** assumes that the strategy may visit at most one row. 5668** 5669** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 5670** SQLite also assumes that if a call to the xUpdate() method is made as 5671** part of the same statement to delete or update a virtual table row and the 5672** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 5673** any database changes. In other words, if the xUpdate() returns 5674** SQLITE_CONSTRAINT, the database contents must be exactly as they were 5675** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 5676** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 5677** the xUpdate method are automatically rolled back by SQLite. 5678** 5679** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 5680** structure for SQLite version 3.8.2. If a virtual table extension is 5681** used with an SQLite version earlier than 3.8.2, the results of attempting 5682** to read or write the estimatedRows field are undefined (but are likely 5683** to included crashing the application). The estimatedRows field should 5684** therefore only be used if [sqlite3_libversion_number()] returns a 5685** value greater than or equal to 3008002. Similarly, the idxFlags field 5686** was added for version 3.9.0. It may therefore only be used if 5687** sqlite3_libversion_number() returns a value greater than or equal to 5688** 3009000. 5689*/ 5690struct sqlite3_index_info { 5691 /* Inputs */ 5692 int nConstraint; /* Number of entries in aConstraint */ 5693 struct sqlite3_index_constraint { 5694 int iColumn; /* Column on left-hand side of constraint */ 5695 unsigned char op; /* Constraint operator */ 5696 unsigned char usable; /* True if this constraint is usable */ 5697 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5698 } *aConstraint; /* Table of WHERE clause constraints */ 5699 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5700 struct sqlite3_index_orderby { 5701 int iColumn; /* Column number */ 5702 unsigned char desc; /* True for DESC. False for ASC. */ 5703 } *aOrderBy; /* The ORDER BY clause */ 5704 /* Outputs */ 5705 struct sqlite3_index_constraint_usage { 5706 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5707 unsigned char omit; /* Do not code a test for this constraint */ 5708 } *aConstraintUsage; 5709 int idxNum; /* Number used to identify the index */ 5710 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5711 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5712 int orderByConsumed; /* True if output is already ordered */ 5713 double estimatedCost; /* Estimated cost of using this index */ 5714 /* Fields below are only available in SQLite 3.8.2 and later */ 5715 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 5716 /* Fields below are only available in SQLite 3.9.0 and later */ 5717 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 5718 /* Fields below are only available in SQLite 3.10.0 and later */ 5719 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 5720}; 5721 5722/* 5723** CAPI3REF: Virtual Table Scan Flags 5724*/ 5725#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 5726 5727/* 5728** CAPI3REF: Virtual Table Constraint Operator Codes 5729** 5730** These macros defined the allowed values for the 5731** [sqlite3_index_info].aConstraint[].op field. Each value represents 5732** an operator that is part of a constraint term in the wHERE clause of 5733** a query that uses a [virtual table]. 5734*/ 5735#define SQLITE_INDEX_CONSTRAINT_EQ 2 5736#define SQLITE_INDEX_CONSTRAINT_GT 4 5737#define SQLITE_INDEX_CONSTRAINT_LE 8 5738#define SQLITE_INDEX_CONSTRAINT_LT 16 5739#define SQLITE_INDEX_CONSTRAINT_GE 32 5740#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5741#define SQLITE_INDEX_CONSTRAINT_LIKE 65 5742#define SQLITE_INDEX_CONSTRAINT_GLOB 66 5743#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 5744 5745/* 5746** CAPI3REF: Register A Virtual Table Implementation 5747** METHOD: sqlite3 5748** 5749** ^These routines are used to register a new [virtual table module] name. 5750** ^Module names must be registered before 5751** creating a new [virtual table] using the module and before using a 5752** preexisting [virtual table] for the module. 5753** 5754** ^The module name is registered on the [database connection] specified 5755** by the first parameter. ^The name of the module is given by the 5756** second parameter. ^The third parameter is a pointer to 5757** the implementation of the [virtual table module]. ^The fourth 5758** parameter is an arbitrary client data pointer that is passed through 5759** into the [xCreate] and [xConnect] methods of the virtual table module 5760** when a new virtual table is be being created or reinitialized. 5761** 5762** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5763** is a pointer to a destructor for the pClientData. ^SQLite will 5764** invoke the destructor function (if it is not NULL) when SQLite 5765** no longer needs the pClientData pointer. ^The destructor will also 5766** be invoked if the call to sqlite3_create_module_v2() fails. 5767** ^The sqlite3_create_module() 5768** interface is equivalent to sqlite3_create_module_v2() with a NULL 5769** destructor. 5770*/ 5771int sqlite3_create_module( 5772 sqlite3 *db, /* SQLite connection to register module with */ 5773 const char *zName, /* Name of the module */ 5774 const sqlite3_module *p, /* Methods for the module */ 5775 void *pClientData /* Client data for xCreate/xConnect */ 5776); 5777int sqlite3_create_module_v2( 5778 sqlite3 *db, /* SQLite connection to register module with */ 5779 const char *zName, /* Name of the module */ 5780 const sqlite3_module *p, /* Methods for the module */ 5781 void *pClientData, /* Client data for xCreate/xConnect */ 5782 void(*xDestroy)(void*) /* Module destructor function */ 5783); 5784 5785/* 5786** CAPI3REF: Virtual Table Instance Object 5787** KEYWORDS: sqlite3_vtab 5788** 5789** Every [virtual table module] implementation uses a subclass 5790** of this object to describe a particular instance 5791** of the [virtual table]. Each subclass will 5792** be tailored to the specific needs of the module implementation. 5793** The purpose of this superclass is to define certain fields that are 5794** common to all module implementations. 5795** 5796** ^Virtual tables methods can set an error message by assigning a 5797** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5798** take care that any prior string is freed by a call to [sqlite3_free()] 5799** prior to assigning a new string to zErrMsg. ^After the error message 5800** is delivered up to the client application, the string will be automatically 5801** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5802*/ 5803struct sqlite3_vtab { 5804 const sqlite3_module *pModule; /* The module for this virtual table */ 5805 int nRef; /* Number of open cursors */ 5806 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5807 /* Virtual table implementations will typically add additional fields */ 5808}; 5809 5810/* 5811** CAPI3REF: Virtual Table Cursor Object 5812** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5813** 5814** Every [virtual table module] implementation uses a subclass of the 5815** following structure to describe cursors that point into the 5816** [virtual table] and are used 5817** to loop through the virtual table. Cursors are created using the 5818** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5819** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5820** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5821** of the module. Each module implementation will define 5822** the content of a cursor structure to suit its own needs. 5823** 5824** This superclass exists in order to define fields of the cursor that 5825** are common to all implementations. 5826*/ 5827struct sqlite3_vtab_cursor { 5828 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5829 /* Virtual table implementations will typically add additional fields */ 5830}; 5831 5832/* 5833** CAPI3REF: Declare The Schema Of A Virtual Table 5834** 5835** ^The [xCreate] and [xConnect] methods of a 5836** [virtual table module] call this interface 5837** to declare the format (the names and datatypes of the columns) of 5838** the virtual tables they implement. 5839*/ 5840int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5841 5842/* 5843** CAPI3REF: Overload A Function For A Virtual Table 5844** METHOD: sqlite3 5845** 5846** ^(Virtual tables can provide alternative implementations of functions 5847** using the [xFindFunction] method of the [virtual table module]. 5848** But global versions of those functions 5849** must exist in order to be overloaded.)^ 5850** 5851** ^(This API makes sure a global version of a function with a particular 5852** name and number of parameters exists. If no such function exists 5853** before this API is called, a new function is created.)^ ^The implementation 5854** of the new function always causes an exception to be thrown. So 5855** the new function is not good for anything by itself. Its only 5856** purpose is to be a placeholder function that can be overloaded 5857** by a [virtual table]. 5858*/ 5859int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5860 5861/* 5862** The interface to the virtual-table mechanism defined above (back up 5863** to a comment remarkably similar to this one) is currently considered 5864** to be experimental. The interface might change in incompatible ways. 5865** If this is a problem for you, do not use the interface at this time. 5866** 5867** When the virtual-table mechanism stabilizes, we will declare the 5868** interface fixed, support it indefinitely, and remove this comment. 5869*/ 5870 5871/* 5872** CAPI3REF: A Handle To An Open BLOB 5873** KEYWORDS: {BLOB handle} {BLOB handles} 5874** 5875** An instance of this object represents an open BLOB on which 5876** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5877** ^Objects of this type are created by [sqlite3_blob_open()] 5878** and destroyed by [sqlite3_blob_close()]. 5879** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5880** can be used to read or write small subsections of the BLOB. 5881** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5882*/ 5883typedef struct sqlite3_blob sqlite3_blob; 5884 5885/* 5886** CAPI3REF: Open A BLOB For Incremental I/O 5887** METHOD: sqlite3 5888** CONSTRUCTOR: sqlite3_blob 5889** 5890** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5891** in row iRow, column zColumn, table zTable in database zDb; 5892** in other words, the same BLOB that would be selected by: 5893** 5894** <pre> 5895** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5896** </pre>)^ 5897** 5898** ^(Parameter zDb is not the filename that contains the database, but 5899** rather the symbolic name of the database. For attached databases, this is 5900** the name that appears after the AS keyword in the [ATTACH] statement. 5901** For the main database file, the database name is "main". For TEMP 5902** tables, the database name is "temp".)^ 5903** 5904** ^If the flags parameter is non-zero, then the BLOB is opened for read 5905** and write access. ^If the flags parameter is zero, the BLOB is opened for 5906** read-only access. 5907** 5908** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 5909** in *ppBlob. Otherwise an [error code] is returned and, unless the error 5910** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 5911** the API is not misused, it is always safe to call [sqlite3_blob_close()] 5912** on *ppBlob after this function it returns. 5913** 5914** This function fails with SQLITE_ERROR if any of the following are true: 5915** <ul> 5916** <li> ^(Database zDb does not exist)^, 5917** <li> ^(Table zTable does not exist within database zDb)^, 5918** <li> ^(Table zTable is a WITHOUT ROWID table)^, 5919** <li> ^(Column zColumn does not exist)^, 5920** <li> ^(Row iRow is not present in the table)^, 5921** <li> ^(The specified column of row iRow contains a value that is not 5922** a TEXT or BLOB value)^, 5923** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 5924** constraint and the blob is being opened for read/write access)^, 5925** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 5926** column zColumn is part of a [child key] definition and the blob is 5927** being opened for read/write access)^. 5928** </ul> 5929** 5930** ^Unless it returns SQLITE_MISUSE, this function sets the 5931** [database connection] error code and message accessible via 5932** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 5933** 5934** 5935** ^(If the row that a BLOB handle points to is modified by an 5936** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5937** then the BLOB handle is marked as "expired". 5938** This is true if any column of the row is changed, even a column 5939** other than the one the BLOB handle is open on.)^ 5940** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5941** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5942** ^(Changes written into a BLOB prior to the BLOB expiring are not 5943** rolled back by the expiration of the BLOB. Such changes will eventually 5944** commit if the transaction continues to completion.)^ 5945** 5946** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5947** the opened blob. ^The size of a blob may not be changed by this 5948** interface. Use the [UPDATE] SQL command to change the size of a 5949** blob. 5950** 5951** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5952** and the built-in [zeroblob] SQL function may be used to create a 5953** zero-filled blob to read or write using the incremental-blob interface. 5954** 5955** To avoid a resource leak, every open [BLOB handle] should eventually 5956** be released by a call to [sqlite3_blob_close()]. 5957*/ 5958int sqlite3_blob_open( 5959 sqlite3*, 5960 const char *zDb, 5961 const char *zTable, 5962 const char *zColumn, 5963 sqlite3_int64 iRow, 5964 int flags, 5965 sqlite3_blob **ppBlob 5966); 5967 5968/* 5969** CAPI3REF: Move a BLOB Handle to a New Row 5970** METHOD: sqlite3_blob 5971** 5972** ^This function is used to move an existing blob handle so that it points 5973** to a different row of the same database table. ^The new row is identified 5974** by the rowid value passed as the second argument. Only the row can be 5975** changed. ^The database, table and column on which the blob handle is open 5976** remain the same. Moving an existing blob handle to a new row can be 5977** faster than closing the existing handle and opening a new one. 5978** 5979** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5980** it must exist and there must be either a blob or text value stored in 5981** the nominated column.)^ ^If the new row is not present in the table, or if 5982** it does not contain a blob or text value, or if another error occurs, an 5983** SQLite error code is returned and the blob handle is considered aborted. 5984** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5985** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5986** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5987** always returns zero. 5988** 5989** ^This function sets the database handle error code and message. 5990*/ 5991int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5992 5993/* 5994** CAPI3REF: Close A BLOB Handle 5995** DESTRUCTOR: sqlite3_blob 5996** 5997** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 5998** unconditionally. Even if this routine returns an error code, the 5999** handle is still closed.)^ 6000** 6001** ^If the blob handle being closed was opened for read-write access, and if 6002** the database is in auto-commit mode and there are no other open read-write 6003** blob handles or active write statements, the current transaction is 6004** committed. ^If an error occurs while committing the transaction, an error 6005** code is returned and the transaction rolled back. 6006** 6007** Calling this function with an argument that is not a NULL pointer or an 6008** open blob handle results in undefined behaviour. ^Calling this routine 6009** with a null pointer (such as would be returned by a failed call to 6010** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6011** is passed a valid open blob handle, the values returned by the 6012** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6013*/ 6014int sqlite3_blob_close(sqlite3_blob *); 6015 6016/* 6017** CAPI3REF: Return The Size Of An Open BLOB 6018** METHOD: sqlite3_blob 6019** 6020** ^Returns the size in bytes of the BLOB accessible via the 6021** successfully opened [BLOB handle] in its only argument. ^The 6022** incremental blob I/O routines can only read or overwriting existing 6023** blob content; they cannot change the size of a blob. 6024** 6025** This routine only works on a [BLOB handle] which has been created 6026** by a prior successful call to [sqlite3_blob_open()] and which has not 6027** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6028** to this routine results in undefined and probably undesirable behavior. 6029*/ 6030int sqlite3_blob_bytes(sqlite3_blob *); 6031 6032/* 6033** CAPI3REF: Read Data From A BLOB Incrementally 6034** METHOD: sqlite3_blob 6035** 6036** ^(This function is used to read data from an open [BLOB handle] into a 6037** caller-supplied buffer. N bytes of data are copied into buffer Z 6038** from the open BLOB, starting at offset iOffset.)^ 6039** 6040** ^If offset iOffset is less than N bytes from the end of the BLOB, 6041** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6042** less than zero, [SQLITE_ERROR] is returned and no data is read. 6043** ^The size of the blob (and hence the maximum value of N+iOffset) 6044** can be determined using the [sqlite3_blob_bytes()] interface. 6045** 6046** ^An attempt to read from an expired [BLOB handle] fails with an 6047** error code of [SQLITE_ABORT]. 6048** 6049** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6050** Otherwise, an [error code] or an [extended error code] is returned.)^ 6051** 6052** This routine only works on a [BLOB handle] which has been created 6053** by a prior successful call to [sqlite3_blob_open()] and which has not 6054** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6055** to this routine results in undefined and probably undesirable behavior. 6056** 6057** See also: [sqlite3_blob_write()]. 6058*/ 6059int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6060 6061/* 6062** CAPI3REF: Write Data Into A BLOB Incrementally 6063** METHOD: sqlite3_blob 6064** 6065** ^(This function is used to write data into an open [BLOB handle] from a 6066** caller-supplied buffer. N bytes of data are copied from the buffer Z 6067** into the open BLOB, starting at offset iOffset.)^ 6068** 6069** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6070** Otherwise, an [error code] or an [extended error code] is returned.)^ 6071** ^Unless SQLITE_MISUSE is returned, this function sets the 6072** [database connection] error code and message accessible via 6073** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6074** 6075** ^If the [BLOB handle] passed as the first argument was not opened for 6076** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6077** this function returns [SQLITE_READONLY]. 6078** 6079** This function may only modify the contents of the BLOB; it is 6080** not possible to increase the size of a BLOB using this API. 6081** ^If offset iOffset is less than N bytes from the end of the BLOB, 6082** [SQLITE_ERROR] is returned and no data is written. The size of the 6083** BLOB (and hence the maximum value of N+iOffset) can be determined 6084** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6085** than zero [SQLITE_ERROR] is returned and no data is written. 6086** 6087** ^An attempt to write to an expired [BLOB handle] fails with an 6088** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6089** before the [BLOB handle] expired are not rolled back by the 6090** expiration of the handle, though of course those changes might 6091** have been overwritten by the statement that expired the BLOB handle 6092** or by other independent statements. 6093** 6094** This routine only works on a [BLOB handle] which has been created 6095** by a prior successful call to [sqlite3_blob_open()] and which has not 6096** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6097** to this routine results in undefined and probably undesirable behavior. 6098** 6099** See also: [sqlite3_blob_read()]. 6100*/ 6101int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6102 6103/* 6104** CAPI3REF: Virtual File System Objects 6105** 6106** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6107** that SQLite uses to interact 6108** with the underlying operating system. Most SQLite builds come with a 6109** single default VFS that is appropriate for the host computer. 6110** New VFSes can be registered and existing VFSes can be unregistered. 6111** The following interfaces are provided. 6112** 6113** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6114** ^Names are case sensitive. 6115** ^Names are zero-terminated UTF-8 strings. 6116** ^If there is no match, a NULL pointer is returned. 6117** ^If zVfsName is NULL then the default VFS is returned. 6118** 6119** ^New VFSes are registered with sqlite3_vfs_register(). 6120** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6121** ^The same VFS can be registered multiple times without injury. 6122** ^To make an existing VFS into the default VFS, register it again 6123** with the makeDflt flag set. If two different VFSes with the 6124** same name are registered, the behavior is undefined. If a 6125** VFS is registered with a name that is NULL or an empty string, 6126** then the behavior is undefined. 6127** 6128** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6129** ^(If the default VFS is unregistered, another VFS is chosen as 6130** the default. The choice for the new VFS is arbitrary.)^ 6131*/ 6132sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6133int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6134int sqlite3_vfs_unregister(sqlite3_vfs*); 6135 6136/* 6137** CAPI3REF: Mutexes 6138** 6139** The SQLite core uses these routines for thread 6140** synchronization. Though they are intended for internal 6141** use by SQLite, code that links against SQLite is 6142** permitted to use any of these routines. 6143** 6144** The SQLite source code contains multiple implementations 6145** of these mutex routines. An appropriate implementation 6146** is selected automatically at compile-time. The following 6147** implementations are available in the SQLite core: 6148** 6149** <ul> 6150** <li> SQLITE_MUTEX_PTHREADS 6151** <li> SQLITE_MUTEX_W32 6152** <li> SQLITE_MUTEX_NOOP 6153** </ul> 6154** 6155** The SQLITE_MUTEX_NOOP implementation is a set of routines 6156** that does no real locking and is appropriate for use in 6157** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6158** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6159** and Windows. 6160** 6161** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6162** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6163** implementation is included with the library. In this case the 6164** application must supply a custom mutex implementation using the 6165** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6166** before calling sqlite3_initialize() or any other public sqlite3_ 6167** function that calls sqlite3_initialize(). 6168** 6169** ^The sqlite3_mutex_alloc() routine allocates a new 6170** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6171** routine returns NULL if it is unable to allocate the requested 6172** mutex. The argument to sqlite3_mutex_alloc() must one of these 6173** integer constants: 6174** 6175** <ul> 6176** <li> SQLITE_MUTEX_FAST 6177** <li> SQLITE_MUTEX_RECURSIVE 6178** <li> SQLITE_MUTEX_STATIC_MASTER 6179** <li> SQLITE_MUTEX_STATIC_MEM 6180** <li> SQLITE_MUTEX_STATIC_OPEN 6181** <li> SQLITE_MUTEX_STATIC_PRNG 6182** <li> SQLITE_MUTEX_STATIC_LRU 6183** <li> SQLITE_MUTEX_STATIC_PMEM 6184** <li> SQLITE_MUTEX_STATIC_APP1 6185** <li> SQLITE_MUTEX_STATIC_APP2 6186** <li> SQLITE_MUTEX_STATIC_APP3 6187** <li> SQLITE_MUTEX_STATIC_VFS1 6188** <li> SQLITE_MUTEX_STATIC_VFS2 6189** <li> SQLITE_MUTEX_STATIC_VFS3 6190** </ul> 6191** 6192** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6193** cause sqlite3_mutex_alloc() to create 6194** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6195** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6196** The mutex implementation does not need to make a distinction 6197** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6198** not want to. SQLite will only request a recursive mutex in 6199** cases where it really needs one. If a faster non-recursive mutex 6200** implementation is available on the host platform, the mutex subsystem 6201** might return such a mutex in response to SQLITE_MUTEX_FAST. 6202** 6203** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6204** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6205** a pointer to a static preexisting mutex. ^Nine static mutexes are 6206** used by the current version of SQLite. Future versions of SQLite 6207** may add additional static mutexes. Static mutexes are for internal 6208** use by SQLite only. Applications that use SQLite mutexes should 6209** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6210** SQLITE_MUTEX_RECURSIVE. 6211** 6212** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6213** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6214** returns a different mutex on every call. ^For the static 6215** mutex types, the same mutex is returned on every call that has 6216** the same type number. 6217** 6218** ^The sqlite3_mutex_free() routine deallocates a previously 6219** allocated dynamic mutex. Attempting to deallocate a static 6220** mutex results in undefined behavior. 6221** 6222** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6223** to enter a mutex. ^If another thread is already within the mutex, 6224** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6225** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6226** upon successful entry. ^(Mutexes created using 6227** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6228** In such cases, the 6229** mutex must be exited an equal number of times before another thread 6230** can enter.)^ If the same thread tries to enter any mutex other 6231** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6232** 6233** ^(Some systems (for example, Windows 95) do not support the operation 6234** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6235** will always return SQLITE_BUSY. The SQLite core only ever uses 6236** sqlite3_mutex_try() as an optimization so this is acceptable 6237** behavior.)^ 6238** 6239** ^The sqlite3_mutex_leave() routine exits a mutex that was 6240** previously entered by the same thread. The behavior 6241** is undefined if the mutex is not currently entered by the 6242** calling thread or is not currently allocated. 6243** 6244** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6245** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6246** behave as no-ops. 6247** 6248** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6249*/ 6250sqlite3_mutex *sqlite3_mutex_alloc(int); 6251void sqlite3_mutex_free(sqlite3_mutex*); 6252void sqlite3_mutex_enter(sqlite3_mutex*); 6253int sqlite3_mutex_try(sqlite3_mutex*); 6254void sqlite3_mutex_leave(sqlite3_mutex*); 6255 6256/* 6257** CAPI3REF: Mutex Methods Object 6258** 6259** An instance of this structure defines the low-level routines 6260** used to allocate and use mutexes. 6261** 6262** Usually, the default mutex implementations provided by SQLite are 6263** sufficient, however the application has the option of substituting a custom 6264** implementation for specialized deployments or systems for which SQLite 6265** does not provide a suitable implementation. In this case, the application 6266** creates and populates an instance of this structure to pass 6267** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6268** Additionally, an instance of this structure can be used as an 6269** output variable when querying the system for the current mutex 6270** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6271** 6272** ^The xMutexInit method defined by this structure is invoked as 6273** part of system initialization by the sqlite3_initialize() function. 6274** ^The xMutexInit routine is called by SQLite exactly once for each 6275** effective call to [sqlite3_initialize()]. 6276** 6277** ^The xMutexEnd method defined by this structure is invoked as 6278** part of system shutdown by the sqlite3_shutdown() function. The 6279** implementation of this method is expected to release all outstanding 6280** resources obtained by the mutex methods implementation, especially 6281** those obtained by the xMutexInit method. ^The xMutexEnd() 6282** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6283** 6284** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6285** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6286** xMutexNotheld) implement the following interfaces (respectively): 6287** 6288** <ul> 6289** <li> [sqlite3_mutex_alloc()] </li> 6290** <li> [sqlite3_mutex_free()] </li> 6291** <li> [sqlite3_mutex_enter()] </li> 6292** <li> [sqlite3_mutex_try()] </li> 6293** <li> [sqlite3_mutex_leave()] </li> 6294** <li> [sqlite3_mutex_held()] </li> 6295** <li> [sqlite3_mutex_notheld()] </li> 6296** </ul>)^ 6297** 6298** The only difference is that the public sqlite3_XXX functions enumerated 6299** above silently ignore any invocations that pass a NULL pointer instead 6300** of a valid mutex handle. The implementations of the methods defined 6301** by this structure are not required to handle this case, the results 6302** of passing a NULL pointer instead of a valid mutex handle are undefined 6303** (i.e. it is acceptable to provide an implementation that segfaults if 6304** it is passed a NULL pointer). 6305** 6306** The xMutexInit() method must be threadsafe. It must be harmless to 6307** invoke xMutexInit() multiple times within the same process and without 6308** intervening calls to xMutexEnd(). Second and subsequent calls to 6309** xMutexInit() must be no-ops. 6310** 6311** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6312** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6313** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6314** memory allocation for a fast or recursive mutex. 6315** 6316** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6317** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6318** If xMutexInit fails in any way, it is expected to clean up after itself 6319** prior to returning. 6320*/ 6321typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6322struct sqlite3_mutex_methods { 6323 int (*xMutexInit)(void); 6324 int (*xMutexEnd)(void); 6325 sqlite3_mutex *(*xMutexAlloc)(int); 6326 void (*xMutexFree)(sqlite3_mutex *); 6327 void (*xMutexEnter)(sqlite3_mutex *); 6328 int (*xMutexTry)(sqlite3_mutex *); 6329 void (*xMutexLeave)(sqlite3_mutex *); 6330 int (*xMutexHeld)(sqlite3_mutex *); 6331 int (*xMutexNotheld)(sqlite3_mutex *); 6332}; 6333 6334/* 6335** CAPI3REF: Mutex Verification Routines 6336** 6337** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6338** are intended for use inside assert() statements. The SQLite core 6339** never uses these routines except inside an assert() and applications 6340** are advised to follow the lead of the core. The SQLite core only 6341** provides implementations for these routines when it is compiled 6342** with the SQLITE_DEBUG flag. External mutex implementations 6343** are only required to provide these routines if SQLITE_DEBUG is 6344** defined and if NDEBUG is not defined. 6345** 6346** These routines should return true if the mutex in their argument 6347** is held or not held, respectively, by the calling thread. 6348** 6349** The implementation is not required to provide versions of these 6350** routines that actually work. If the implementation does not provide working 6351** versions of these routines, it should at least provide stubs that always 6352** return true so that one does not get spurious assertion failures. 6353** 6354** If the argument to sqlite3_mutex_held() is a NULL pointer then 6355** the routine should return 1. This seems counter-intuitive since 6356** clearly the mutex cannot be held if it does not exist. But 6357** the reason the mutex does not exist is because the build is not 6358** using mutexes. And we do not want the assert() containing the 6359** call to sqlite3_mutex_held() to fail, so a non-zero return is 6360** the appropriate thing to do. The sqlite3_mutex_notheld() 6361** interface should also return 1 when given a NULL pointer. 6362*/ 6363#ifndef NDEBUG 6364int sqlite3_mutex_held(sqlite3_mutex*); 6365int sqlite3_mutex_notheld(sqlite3_mutex*); 6366#endif 6367 6368/* 6369** CAPI3REF: Mutex Types 6370** 6371** The [sqlite3_mutex_alloc()] interface takes a single argument 6372** which is one of these integer constants. 6373** 6374** The set of static mutexes may change from one SQLite release to the 6375** next. Applications that override the built-in mutex logic must be 6376** prepared to accommodate additional static mutexes. 6377*/ 6378#define SQLITE_MUTEX_FAST 0 6379#define SQLITE_MUTEX_RECURSIVE 1 6380#define SQLITE_MUTEX_STATIC_MASTER 2 6381#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6382#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6383#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6384#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 6385#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6386#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6387#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6388#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6389#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6390#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6391#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6392#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6393#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6394 6395/* 6396** CAPI3REF: Retrieve the mutex for a database connection 6397** METHOD: sqlite3 6398** 6399** ^This interface returns a pointer the [sqlite3_mutex] object that 6400** serializes access to the [database connection] given in the argument 6401** when the [threading mode] is Serialized. 6402** ^If the [threading mode] is Single-thread or Multi-thread then this 6403** routine returns a NULL pointer. 6404*/ 6405sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6406 6407/* 6408** CAPI3REF: Low-Level Control Of Database Files 6409** METHOD: sqlite3 6410** 6411** ^The [sqlite3_file_control()] interface makes a direct call to the 6412** xFileControl method for the [sqlite3_io_methods] object associated 6413** with a particular database identified by the second argument. ^The 6414** name of the database is "main" for the main database or "temp" for the 6415** TEMP database, or the name that appears after the AS keyword for 6416** databases that are added using the [ATTACH] SQL command. 6417** ^A NULL pointer can be used in place of "main" to refer to the 6418** main database file. 6419** ^The third and fourth parameters to this routine 6420** are passed directly through to the second and third parameters of 6421** the xFileControl method. ^The return value of the xFileControl 6422** method becomes the return value of this routine. 6423** 6424** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6425** a pointer to the underlying [sqlite3_file] object to be written into 6426** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6427** case is a short-circuit path which does not actually invoke the 6428** underlying sqlite3_io_methods.xFileControl method. 6429** 6430** ^If the second parameter (zDbName) does not match the name of any 6431** open database file, then SQLITE_ERROR is returned. ^This error 6432** code is not remembered and will not be recalled by [sqlite3_errcode()] 6433** or [sqlite3_errmsg()]. The underlying xFileControl method might 6434** also return SQLITE_ERROR. There is no way to distinguish between 6435** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6436** xFileControl method. 6437** 6438** See also: [SQLITE_FCNTL_LOCKSTATE] 6439*/ 6440int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6441 6442/* 6443** CAPI3REF: Testing Interface 6444** 6445** ^The sqlite3_test_control() interface is used to read out internal 6446** state of SQLite and to inject faults into SQLite for testing 6447** purposes. ^The first parameter is an operation code that determines 6448** the number, meaning, and operation of all subsequent parameters. 6449** 6450** This interface is not for use by applications. It exists solely 6451** for verifying the correct operation of the SQLite library. Depending 6452** on how the SQLite library is compiled, this interface might not exist. 6453** 6454** The details of the operation codes, their meanings, the parameters 6455** they take, and what they do are all subject to change without notice. 6456** Unlike most of the SQLite API, this function is not guaranteed to 6457** operate consistently from one release to the next. 6458*/ 6459int sqlite3_test_control(int op, ...); 6460 6461/* 6462** CAPI3REF: Testing Interface Operation Codes 6463** 6464** These constants are the valid operation code parameters used 6465** as the first argument to [sqlite3_test_control()]. 6466** 6467** These parameters and their meanings are subject to change 6468** without notice. These values are for testing purposes only. 6469** Applications should not use any of these parameters or the 6470** [sqlite3_test_control()] interface. 6471*/ 6472#define SQLITE_TESTCTRL_FIRST 5 6473#define SQLITE_TESTCTRL_PRNG_SAVE 5 6474#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6475#define SQLITE_TESTCTRL_PRNG_RESET 7 6476#define SQLITE_TESTCTRL_BITVEC_TEST 8 6477#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6478#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6479#define SQLITE_TESTCTRL_PENDING_BYTE 11 6480#define SQLITE_TESTCTRL_ASSERT 12 6481#define SQLITE_TESTCTRL_ALWAYS 13 6482#define SQLITE_TESTCTRL_RESERVE 14 6483#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6484#define SQLITE_TESTCTRL_ISKEYWORD 16 6485#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6486#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6487#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6488#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6489#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6490#define SQLITE_TESTCTRL_BYTEORDER 22 6491#define SQLITE_TESTCTRL_ISINIT 23 6492#define SQLITE_TESTCTRL_SORTER_MMAP 24 6493#define SQLITE_TESTCTRL_IMPOSTER 25 6494#define SQLITE_TESTCTRL_LAST 25 6495 6496/* 6497** CAPI3REF: SQLite Runtime Status 6498** 6499** ^These interfaces are used to retrieve runtime status information 6500** about the performance of SQLite, and optionally to reset various 6501** highwater marks. ^The first argument is an integer code for 6502** the specific parameter to measure. ^(Recognized integer codes 6503** are of the form [status parameters | SQLITE_STATUS_...].)^ 6504** ^The current value of the parameter is returned into *pCurrent. 6505** ^The highest recorded value is returned in *pHighwater. ^If the 6506** resetFlag is true, then the highest record value is reset after 6507** *pHighwater is written. ^(Some parameters do not record the highest 6508** value. For those parameters 6509** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6510** ^(Other parameters record only the highwater mark and not the current 6511** value. For these latter parameters nothing is written into *pCurrent.)^ 6512** 6513** ^The sqlite3_status() and sqlite3_status64() routines return 6514** SQLITE_OK on success and a non-zero [error code] on failure. 6515** 6516** If either the current value or the highwater mark is too large to 6517** be represented by a 32-bit integer, then the values returned by 6518** sqlite3_status() are undefined. 6519** 6520** See also: [sqlite3_db_status()] 6521*/ 6522int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6523int sqlite3_status64( 6524 int op, 6525 sqlite3_int64 *pCurrent, 6526 sqlite3_int64 *pHighwater, 6527 int resetFlag 6528); 6529 6530 6531/* 6532** CAPI3REF: Status Parameters 6533** KEYWORDS: {status parameters} 6534** 6535** These integer constants designate various run-time status parameters 6536** that can be returned by [sqlite3_status()]. 6537** 6538** <dl> 6539** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6540** <dd>This parameter is the current amount of memory checked out 6541** using [sqlite3_malloc()], either directly or indirectly. The 6542** figure includes calls made to [sqlite3_malloc()] by the application 6543** and internal memory usage by the SQLite library. Scratch memory 6544** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6545** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6546** this parameter. The amount returned is the sum of the allocation 6547** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6548** 6549** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6550** <dd>This parameter records the largest memory allocation request 6551** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6552** internal equivalents). Only the value returned in the 6553** *pHighwater parameter to [sqlite3_status()] is of interest. 6554** The value written into the *pCurrent parameter is undefined.</dd>)^ 6555** 6556** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6557** <dd>This parameter records the number of separate memory allocations 6558** currently checked out.</dd>)^ 6559** 6560** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6561** <dd>This parameter returns the number of pages used out of the 6562** [pagecache memory allocator] that was configured using 6563** [SQLITE_CONFIG_PAGECACHE]. The 6564** value returned is in pages, not in bytes.</dd>)^ 6565** 6566** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6567** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6568** <dd>This parameter returns the number of bytes of page cache 6569** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6570** buffer and where forced to overflow to [sqlite3_malloc()]. The 6571** returned value includes allocations that overflowed because they 6572** where too large (they were larger than the "sz" parameter to 6573** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6574** no space was left in the page cache.</dd>)^ 6575** 6576** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6577** <dd>This parameter records the largest memory allocation request 6578** handed to [pagecache memory allocator]. Only the value returned in the 6579** *pHighwater parameter to [sqlite3_status()] is of interest. 6580** The value written into the *pCurrent parameter is undefined.</dd>)^ 6581** 6582** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6583** <dd>This parameter returns the number of allocations used out of the 6584** [scratch memory allocator] configured using 6585** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6586** in bytes. Since a single thread may only have one scratch allocation 6587** outstanding at time, this parameter also reports the number of threads 6588** using scratch memory at the same time.</dd>)^ 6589** 6590** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6591** <dd>This parameter returns the number of bytes of scratch memory 6592** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6593** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6594** returned include overflows because the requested allocation was too 6595** larger (that is, because the requested allocation was larger than the 6596** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6597** slots were available. 6598** </dd>)^ 6599** 6600** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6601** <dd>This parameter records the largest memory allocation request 6602** handed to [scratch memory allocator]. Only the value returned in the 6603** *pHighwater parameter to [sqlite3_status()] is of interest. 6604** The value written into the *pCurrent parameter is undefined.</dd>)^ 6605** 6606** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6607** <dd>The *pHighwater parameter records the deepest parser stack. 6608** The *pCurrent value is undefined. The *pHighwater value is only 6609** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6610** </dl> 6611** 6612** New status parameters may be added from time to time. 6613*/ 6614#define SQLITE_STATUS_MEMORY_USED 0 6615#define SQLITE_STATUS_PAGECACHE_USED 1 6616#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6617#define SQLITE_STATUS_SCRATCH_USED 3 6618#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6619#define SQLITE_STATUS_MALLOC_SIZE 5 6620#define SQLITE_STATUS_PARSER_STACK 6 6621#define SQLITE_STATUS_PAGECACHE_SIZE 7 6622#define SQLITE_STATUS_SCRATCH_SIZE 8 6623#define SQLITE_STATUS_MALLOC_COUNT 9 6624 6625/* 6626** CAPI3REF: Database Connection Status 6627** METHOD: sqlite3 6628** 6629** ^This interface is used to retrieve runtime status information 6630** about a single [database connection]. ^The first argument is the 6631** database connection object to be interrogated. ^The second argument 6632** is an integer constant, taken from the set of 6633** [SQLITE_DBSTATUS options], that 6634** determines the parameter to interrogate. The set of 6635** [SQLITE_DBSTATUS options] is likely 6636** to grow in future releases of SQLite. 6637** 6638** ^The current value of the requested parameter is written into *pCur 6639** and the highest instantaneous value is written into *pHiwtr. ^If 6640** the resetFlg is true, then the highest instantaneous value is 6641** reset back down to the current value. 6642** 6643** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6644** non-zero [error code] on failure. 6645** 6646** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6647*/ 6648int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6649 6650/* 6651** CAPI3REF: Status Parameters for database connections 6652** KEYWORDS: {SQLITE_DBSTATUS options} 6653** 6654** These constants are the available integer "verbs" that can be passed as 6655** the second argument to the [sqlite3_db_status()] interface. 6656** 6657** New verbs may be added in future releases of SQLite. Existing verbs 6658** might be discontinued. Applications should check the return code from 6659** [sqlite3_db_status()] to make sure that the call worked. 6660** The [sqlite3_db_status()] interface will return a non-zero error code 6661** if a discontinued or unsupported verb is invoked. 6662** 6663** <dl> 6664** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6665** <dd>This parameter returns the number of lookaside memory slots currently 6666** checked out.</dd>)^ 6667** 6668** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6669** <dd>This parameter returns the number malloc attempts that were 6670** satisfied using lookaside memory. Only the high-water value is meaningful; 6671** the current value is always zero.)^ 6672** 6673** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6674** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6675** <dd>This parameter returns the number malloc attempts that might have 6676** been satisfied using lookaside memory but failed due to the amount of 6677** memory requested being larger than the lookaside slot size. 6678** Only the high-water value is meaningful; 6679** the current value is always zero.)^ 6680** 6681** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6682** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6683** <dd>This parameter returns the number malloc attempts that might have 6684** been satisfied using lookaside memory but failed due to all lookaside 6685** memory already being in use. 6686** Only the high-water value is meaningful; 6687** the current value is always zero.)^ 6688** 6689** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6690** <dd>This parameter returns the approximate number of bytes of heap 6691** memory used by all pager caches associated with the database connection.)^ 6692** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6693** 6694** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6695** <dd>This parameter returns the approximate number of bytes of heap 6696** memory used to store the schema for all databases associated 6697** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6698** ^The full amount of memory used by the schemas is reported, even if the 6699** schema memory is shared with other database connections due to 6700** [shared cache mode] being enabled. 6701** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6702** 6703** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6704** <dd>This parameter returns the approximate number of bytes of heap 6705** and lookaside memory used by all prepared statements associated with 6706** the database connection.)^ 6707** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6708** </dd> 6709** 6710** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6711** <dd>This parameter returns the number of pager cache hits that have 6712** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6713** is always 0. 6714** </dd> 6715** 6716** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6717** <dd>This parameter returns the number of pager cache misses that have 6718** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6719** is always 0. 6720** </dd> 6721** 6722** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6723** <dd>This parameter returns the number of dirty cache entries that have 6724** been written to disk. Specifically, the number of pages written to the 6725** wal file in wal mode databases, or the number of pages written to the 6726** database file in rollback mode databases. Any pages written as part of 6727** transaction rollback or database recovery operations are not included. 6728** If an IO or other error occurs while writing a page to disk, the effect 6729** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6730** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6731** </dd> 6732** 6733** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 6734** <dd>This parameter returns zero for the current value if and only if 6735** all foreign key constraints (deferred or immediate) have been 6736** resolved.)^ ^The highwater mark is always 0. 6737** </dd> 6738** </dl> 6739*/ 6740#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6741#define SQLITE_DBSTATUS_CACHE_USED 1 6742#define SQLITE_DBSTATUS_SCHEMA_USED 2 6743#define SQLITE_DBSTATUS_STMT_USED 3 6744#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6745#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6746#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6747#define SQLITE_DBSTATUS_CACHE_HIT 7 6748#define SQLITE_DBSTATUS_CACHE_MISS 8 6749#define SQLITE_DBSTATUS_CACHE_WRITE 9 6750#define SQLITE_DBSTATUS_DEFERRED_FKS 10 6751#define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */ 6752 6753 6754/* 6755** CAPI3REF: Prepared Statement Status 6756** METHOD: sqlite3_stmt 6757** 6758** ^(Each prepared statement maintains various 6759** [SQLITE_STMTSTATUS counters] that measure the number 6760** of times it has performed specific operations.)^ These counters can 6761** be used to monitor the performance characteristics of the prepared 6762** statements. For example, if the number of table steps greatly exceeds 6763** the number of table searches or result rows, that would tend to indicate 6764** that the prepared statement is using a full table scan rather than 6765** an index. 6766** 6767** ^(This interface is used to retrieve and reset counter values from 6768** a [prepared statement]. The first argument is the prepared statement 6769** object to be interrogated. The second argument 6770** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6771** to be interrogated.)^ 6772** ^The current value of the requested counter is returned. 6773** ^If the resetFlg is true, then the counter is reset to zero after this 6774** interface call returns. 6775** 6776** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6777*/ 6778int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6779 6780/* 6781** CAPI3REF: Status Parameters for prepared statements 6782** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6783** 6784** These preprocessor macros define integer codes that name counter 6785** values associated with the [sqlite3_stmt_status()] interface. 6786** The meanings of the various counters are as follows: 6787** 6788** <dl> 6789** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6790** <dd>^This is the number of times that SQLite has stepped forward in 6791** a table as part of a full table scan. Large numbers for this counter 6792** may indicate opportunities for performance improvement through 6793** careful use of indices.</dd> 6794** 6795** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6796** <dd>^This is the number of sort operations that have occurred. 6797** A non-zero value in this counter may indicate an opportunity to 6798** improvement performance through careful use of indices.</dd> 6799** 6800** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6801** <dd>^This is the number of rows inserted into transient indices that 6802** were created automatically in order to help joins run faster. 6803** A non-zero value in this counter may indicate an opportunity to 6804** improvement performance by adding permanent indices that do not 6805** need to be reinitialized each time the statement is run.</dd> 6806** 6807** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 6808** <dd>^This is the number of virtual machine operations executed 6809** by the prepared statement if that number is less than or equal 6810** to 2147483647. The number of virtual machine operations can be 6811** used as a proxy for the total work done by the prepared statement. 6812** If the number of virtual machine operations exceeds 2147483647 6813** then the value returned by this statement status code is undefined. 6814** </dd> 6815** </dl> 6816*/ 6817#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6818#define SQLITE_STMTSTATUS_SORT 2 6819#define SQLITE_STMTSTATUS_AUTOINDEX 3 6820#define SQLITE_STMTSTATUS_VM_STEP 4 6821 6822/* 6823** CAPI3REF: Custom Page Cache Object 6824** 6825** The sqlite3_pcache type is opaque. It is implemented by 6826** the pluggable module. The SQLite core has no knowledge of 6827** its size or internal structure and never deals with the 6828** sqlite3_pcache object except by holding and passing pointers 6829** to the object. 6830** 6831** See [sqlite3_pcache_methods2] for additional information. 6832*/ 6833typedef struct sqlite3_pcache sqlite3_pcache; 6834 6835/* 6836** CAPI3REF: Custom Page Cache Object 6837** 6838** The sqlite3_pcache_page object represents a single page in the 6839** page cache. The page cache will allocate instances of this 6840** object. Various methods of the page cache use pointers to instances 6841** of this object as parameters or as their return value. 6842** 6843** See [sqlite3_pcache_methods2] for additional information. 6844*/ 6845typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6846struct sqlite3_pcache_page { 6847 void *pBuf; /* The content of the page */ 6848 void *pExtra; /* Extra information associated with the page */ 6849}; 6850 6851/* 6852** CAPI3REF: Application Defined Page Cache. 6853** KEYWORDS: {page cache} 6854** 6855** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6856** register an alternative page cache implementation by passing in an 6857** instance of the sqlite3_pcache_methods2 structure.)^ 6858** In many applications, most of the heap memory allocated by 6859** SQLite is used for the page cache. 6860** By implementing a 6861** custom page cache using this API, an application can better control 6862** the amount of memory consumed by SQLite, the way in which 6863** that memory is allocated and released, and the policies used to 6864** determine exactly which parts of a database file are cached and for 6865** how long. 6866** 6867** The alternative page cache mechanism is an 6868** extreme measure that is only needed by the most demanding applications. 6869** The built-in page cache is recommended for most uses. 6870** 6871** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6872** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6873** the application may discard the parameter after the call to 6874** [sqlite3_config()] returns.)^ 6875** 6876** [[the xInit() page cache method]] 6877** ^(The xInit() method is called once for each effective 6878** call to [sqlite3_initialize()])^ 6879** (usually only once during the lifetime of the process). ^(The xInit() 6880** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6881** The intent of the xInit() method is to set up global data structures 6882** required by the custom page cache implementation. 6883** ^(If the xInit() method is NULL, then the 6884** built-in default page cache is used instead of the application defined 6885** page cache.)^ 6886** 6887** [[the xShutdown() page cache method]] 6888** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6889** It can be used to clean up 6890** any outstanding resources before process shutdown, if required. 6891** ^The xShutdown() method may be NULL. 6892** 6893** ^SQLite automatically serializes calls to the xInit method, 6894** so the xInit method need not be threadsafe. ^The 6895** xShutdown method is only called from [sqlite3_shutdown()] so it does 6896** not need to be threadsafe either. All other methods must be threadsafe 6897** in multithreaded applications. 6898** 6899** ^SQLite will never invoke xInit() more than once without an intervening 6900** call to xShutdown(). 6901** 6902** [[the xCreate() page cache methods]] 6903** ^SQLite invokes the xCreate() method to construct a new cache instance. 6904** SQLite will typically create one cache instance for each open database file, 6905** though this is not guaranteed. ^The 6906** first parameter, szPage, is the size in bytes of the pages that must 6907** be allocated by the cache. ^szPage will always a power of two. ^The 6908** second parameter szExtra is a number of bytes of extra storage 6909** associated with each page cache entry. ^The szExtra parameter will 6910** a number less than 250. SQLite will use the 6911** extra szExtra bytes on each page to store metadata about the underlying 6912** database page on disk. The value passed into szExtra depends 6913** on the SQLite version, the target platform, and how SQLite was compiled. 6914** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6915** created will be used to cache database pages of a file stored on disk, or 6916** false if it is used for an in-memory database. The cache implementation 6917** does not have to do anything special based with the value of bPurgeable; 6918** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6919** never invoke xUnpin() except to deliberately delete a page. 6920** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6921** false will always have the "discard" flag set to true. 6922** ^Hence, a cache created with bPurgeable false will 6923** never contain any unpinned pages. 6924** 6925** [[the xCachesize() page cache method]] 6926** ^(The xCachesize() method may be called at any time by SQLite to set the 6927** suggested maximum cache-size (number of pages stored by) the cache 6928** instance passed as the first argument. This is the value configured using 6929** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6930** parameter, the implementation is not required to do anything with this 6931** value; it is advisory only. 6932** 6933** [[the xPagecount() page cache methods]] 6934** The xPagecount() method must return the number of pages currently 6935** stored in the cache, both pinned and unpinned. 6936** 6937** [[the xFetch() page cache methods]] 6938** The xFetch() method locates a page in the cache and returns a pointer to 6939** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6940** The pBuf element of the returned sqlite3_pcache_page object will be a 6941** pointer to a buffer of szPage bytes used to store the content of a 6942** single database page. The pExtra element of sqlite3_pcache_page will be 6943** a pointer to the szExtra bytes of extra storage that SQLite has requested 6944** for each entry in the page cache. 6945** 6946** The page to be fetched is determined by the key. ^The minimum key value 6947** is 1. After it has been retrieved using xFetch, the page is considered 6948** to be "pinned". 6949** 6950** If the requested page is already in the page cache, then the page cache 6951** implementation must return a pointer to the page buffer with its content 6952** intact. If the requested page is not already in the cache, then the 6953** cache implementation should use the value of the createFlag 6954** parameter to help it determined what action to take: 6955** 6956** <table border=1 width=85% align=center> 6957** <tr><th> createFlag <th> Behavior when page is not already in cache 6958** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6959** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6960** Otherwise return NULL. 6961** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6962** NULL if allocating a new page is effectively impossible. 6963** </table> 6964** 6965** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6966** will only use a createFlag of 2 after a prior call with a createFlag of 1 6967** failed.)^ In between the to xFetch() calls, SQLite may 6968** attempt to unpin one or more cache pages by spilling the content of 6969** pinned pages to disk and synching the operating system disk cache. 6970** 6971** [[the xUnpin() page cache method]] 6972** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6973** as its second argument. If the third parameter, discard, is non-zero, 6974** then the page must be evicted from the cache. 6975** ^If the discard parameter is 6976** zero, then the page may be discarded or retained at the discretion of 6977** page cache implementation. ^The page cache implementation 6978** may choose to evict unpinned pages at any time. 6979** 6980** The cache must not perform any reference counting. A single 6981** call to xUnpin() unpins the page regardless of the number of prior calls 6982** to xFetch(). 6983** 6984** [[the xRekey() page cache methods]] 6985** The xRekey() method is used to change the key value associated with the 6986** page passed as the second argument. If the cache 6987** previously contains an entry associated with newKey, it must be 6988** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6989** to be pinned. 6990** 6991** When SQLite calls the xTruncate() method, the cache must discard all 6992** existing cache entries with page numbers (keys) greater than or equal 6993** to the value of the iLimit parameter passed to xTruncate(). If any 6994** of these pages are pinned, they are implicitly unpinned, meaning that 6995** they can be safely discarded. 6996** 6997** [[the xDestroy() page cache method]] 6998** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6999** All resources associated with the specified cache should be freed. ^After 7000** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7001** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7002** functions. 7003** 7004** [[the xShrink() page cache method]] 7005** ^SQLite invokes the xShrink() method when it wants the page cache to 7006** free up as much of heap memory as possible. The page cache implementation 7007** is not obligated to free any memory, but well-behaved implementations should 7008** do their best. 7009*/ 7010typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7011struct sqlite3_pcache_methods2 { 7012 int iVersion; 7013 void *pArg; 7014 int (*xInit)(void*); 7015 void (*xShutdown)(void*); 7016 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7017 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7018 int (*xPagecount)(sqlite3_pcache*); 7019 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7020 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7021 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7022 unsigned oldKey, unsigned newKey); 7023 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7024 void (*xDestroy)(sqlite3_pcache*); 7025 void (*xShrink)(sqlite3_pcache*); 7026}; 7027 7028/* 7029** This is the obsolete pcache_methods object that has now been replaced 7030** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7031** retained in the header file for backwards compatibility only. 7032*/ 7033typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7034struct sqlite3_pcache_methods { 7035 void *pArg; 7036 int (*xInit)(void*); 7037 void (*xShutdown)(void*); 7038 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7039 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7040 int (*xPagecount)(sqlite3_pcache*); 7041 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7042 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7043 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7044 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7045 void (*xDestroy)(sqlite3_pcache*); 7046}; 7047 7048 7049/* 7050** CAPI3REF: Online Backup Object 7051** 7052** The sqlite3_backup object records state information about an ongoing 7053** online backup operation. ^The sqlite3_backup object is created by 7054** a call to [sqlite3_backup_init()] and is destroyed by a call to 7055** [sqlite3_backup_finish()]. 7056** 7057** See Also: [Using the SQLite Online Backup API] 7058*/ 7059typedef struct sqlite3_backup sqlite3_backup; 7060 7061/* 7062** CAPI3REF: Online Backup API. 7063** 7064** The backup API copies the content of one database into another. 7065** It is useful either for creating backups of databases or 7066** for copying in-memory databases to or from persistent files. 7067** 7068** See Also: [Using the SQLite Online Backup API] 7069** 7070** ^SQLite holds a write transaction open on the destination database file 7071** for the duration of the backup operation. 7072** ^The source database is read-locked only while it is being read; 7073** it is not locked continuously for the entire backup operation. 7074** ^Thus, the backup may be performed on a live source database without 7075** preventing other database connections from 7076** reading or writing to the source database while the backup is underway. 7077** 7078** ^(To perform a backup operation: 7079** <ol> 7080** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7081** backup, 7082** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7083** the data between the two databases, and finally 7084** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7085** associated with the backup operation. 7086** </ol>)^ 7087** There should be exactly one call to sqlite3_backup_finish() for each 7088** successful call to sqlite3_backup_init(). 7089** 7090** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7091** 7092** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7093** [database connection] associated with the destination database 7094** and the database name, respectively. 7095** ^The database name is "main" for the main database, "temp" for the 7096** temporary database, or the name specified after the AS keyword in 7097** an [ATTACH] statement for an attached database. 7098** ^The S and M arguments passed to 7099** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7100** and database name of the source database, respectively. 7101** ^The source and destination [database connections] (parameters S and D) 7102** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7103** an error. 7104** 7105** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if 7106** there is already a read or read-write transaction open on the 7107** destination database. 7108** 7109** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7110** returned and an error code and error message are stored in the 7111** destination [database connection] D. 7112** ^The error code and message for the failed call to sqlite3_backup_init() 7113** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7114** [sqlite3_errmsg16()] functions. 7115** ^A successful call to sqlite3_backup_init() returns a pointer to an 7116** [sqlite3_backup] object. 7117** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7118** sqlite3_backup_finish() functions to perform the specified backup 7119** operation. 7120** 7121** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7122** 7123** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7124** the source and destination databases specified by [sqlite3_backup] object B. 7125** ^If N is negative, all remaining source pages are copied. 7126** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7127** are still more pages to be copied, then the function returns [SQLITE_OK]. 7128** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7129** from source to destination, then it returns [SQLITE_DONE]. 7130** ^If an error occurs while running sqlite3_backup_step(B,N), 7131** then an [error code] is returned. ^As well as [SQLITE_OK] and 7132** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7133** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7134** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7135** 7136** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7137** <ol> 7138** <li> the destination database was opened read-only, or 7139** <li> the destination database is using write-ahead-log journaling 7140** and the destination and source page sizes differ, or 7141** <li> the destination database is an in-memory database and the 7142** destination and source page sizes differ. 7143** </ol>)^ 7144** 7145** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7146** the [sqlite3_busy_handler | busy-handler function] 7147** is invoked (if one is specified). ^If the 7148** busy-handler returns non-zero before the lock is available, then 7149** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7150** sqlite3_backup_step() can be retried later. ^If the source 7151** [database connection] 7152** is being used to write to the source database when sqlite3_backup_step() 7153** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7154** case the call to sqlite3_backup_step() can be retried later on. ^(If 7155** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7156** [SQLITE_READONLY] is returned, then 7157** there is no point in retrying the call to sqlite3_backup_step(). These 7158** errors are considered fatal.)^ The application must accept 7159** that the backup operation has failed and pass the backup operation handle 7160** to the sqlite3_backup_finish() to release associated resources. 7161** 7162** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7163** on the destination file. ^The exclusive lock is not released until either 7164** sqlite3_backup_finish() is called or the backup operation is complete 7165** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7166** sqlite3_backup_step() obtains a [shared lock] on the source database that 7167** lasts for the duration of the sqlite3_backup_step() call. 7168** ^Because the source database is not locked between calls to 7169** sqlite3_backup_step(), the source database may be modified mid-way 7170** through the backup process. ^If the source database is modified by an 7171** external process or via a database connection other than the one being 7172** used by the backup operation, then the backup will be automatically 7173** restarted by the next call to sqlite3_backup_step(). ^If the source 7174** database is modified by the using the same database connection as is used 7175** by the backup operation, then the backup database is automatically 7176** updated at the same time. 7177** 7178** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7179** 7180** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7181** application wishes to abandon the backup operation, the application 7182** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7183** ^The sqlite3_backup_finish() interfaces releases all 7184** resources associated with the [sqlite3_backup] object. 7185** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7186** active write-transaction on the destination database is rolled back. 7187** The [sqlite3_backup] object is invalid 7188** and may not be used following a call to sqlite3_backup_finish(). 7189** 7190** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7191** sqlite3_backup_step() errors occurred, regardless or whether or not 7192** sqlite3_backup_step() completed. 7193** ^If an out-of-memory condition or IO error occurred during any prior 7194** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7195** sqlite3_backup_finish() returns the corresponding [error code]. 7196** 7197** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7198** is not a permanent error and does not affect the return value of 7199** sqlite3_backup_finish(). 7200** 7201** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7202** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7203** 7204** ^The sqlite3_backup_remaining() routine returns the number of pages still 7205** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7206** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7207** in the source database at the conclusion of the most recent 7208** sqlite3_backup_step(). 7209** ^(The values returned by these functions are only updated by 7210** sqlite3_backup_step(). If the source database is modified in a way that 7211** changes the size of the source database or the number of pages remaining, 7212** those changes are not reflected in the output of sqlite3_backup_pagecount() 7213** and sqlite3_backup_remaining() until after the next 7214** sqlite3_backup_step().)^ 7215** 7216** <b>Concurrent Usage of Database Handles</b> 7217** 7218** ^The source [database connection] may be used by the application for other 7219** purposes while a backup operation is underway or being initialized. 7220** ^If SQLite is compiled and configured to support threadsafe database 7221** connections, then the source database connection may be used concurrently 7222** from within other threads. 7223** 7224** However, the application must guarantee that the destination 7225** [database connection] is not passed to any other API (by any thread) after 7226** sqlite3_backup_init() is called and before the corresponding call to 7227** sqlite3_backup_finish(). SQLite does not currently check to see 7228** if the application incorrectly accesses the destination [database connection] 7229** and so no error code is reported, but the operations may malfunction 7230** nevertheless. Use of the destination database connection while a 7231** backup is in progress might also also cause a mutex deadlock. 7232** 7233** If running in [shared cache mode], the application must 7234** guarantee that the shared cache used by the destination database 7235** is not accessed while the backup is running. In practice this means 7236** that the application must guarantee that the disk file being 7237** backed up to is not accessed by any connection within the process, 7238** not just the specific connection that was passed to sqlite3_backup_init(). 7239** 7240** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7241** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7242** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7243** APIs are not strictly speaking threadsafe. If they are invoked at the 7244** same time as another thread is invoking sqlite3_backup_step() it is 7245** possible that they return invalid values. 7246*/ 7247sqlite3_backup *sqlite3_backup_init( 7248 sqlite3 *pDest, /* Destination database handle */ 7249 const char *zDestName, /* Destination database name */ 7250 sqlite3 *pSource, /* Source database handle */ 7251 const char *zSourceName /* Source database name */ 7252); 7253int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7254int sqlite3_backup_finish(sqlite3_backup *p); 7255int sqlite3_backup_remaining(sqlite3_backup *p); 7256int sqlite3_backup_pagecount(sqlite3_backup *p); 7257 7258/* 7259** CAPI3REF: Unlock Notification 7260** METHOD: sqlite3 7261** 7262** ^When running in shared-cache mode, a database operation may fail with 7263** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7264** individual tables within the shared-cache cannot be obtained. See 7265** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7266** ^This API may be used to register a callback that SQLite will invoke 7267** when the connection currently holding the required lock relinquishes it. 7268** ^This API is only available if the library was compiled with the 7269** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7270** 7271** See Also: [Using the SQLite Unlock Notification Feature]. 7272** 7273** ^Shared-cache locks are released when a database connection concludes 7274** its current transaction, either by committing it or rolling it back. 7275** 7276** ^When a connection (known as the blocked connection) fails to obtain a 7277** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7278** identity of the database connection (the blocking connection) that 7279** has locked the required resource is stored internally. ^After an 7280** application receives an SQLITE_LOCKED error, it may call the 7281** sqlite3_unlock_notify() method with the blocked connection handle as 7282** the first argument to register for a callback that will be invoked 7283** when the blocking connections current transaction is concluded. ^The 7284** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7285** call that concludes the blocking connections transaction. 7286** 7287** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7288** there is a chance that the blocking connection will have already 7289** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7290** If this happens, then the specified callback is invoked immediately, 7291** from within the call to sqlite3_unlock_notify().)^ 7292** 7293** ^If the blocked connection is attempting to obtain a write-lock on a 7294** shared-cache table, and more than one other connection currently holds 7295** a read-lock on the same table, then SQLite arbitrarily selects one of 7296** the other connections to use as the blocking connection. 7297** 7298** ^(There may be at most one unlock-notify callback registered by a 7299** blocked connection. If sqlite3_unlock_notify() is called when the 7300** blocked connection already has a registered unlock-notify callback, 7301** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7302** called with a NULL pointer as its second argument, then any existing 7303** unlock-notify callback is canceled. ^The blocked connections 7304** unlock-notify callback may also be canceled by closing the blocked 7305** connection using [sqlite3_close()]. 7306** 7307** The unlock-notify callback is not reentrant. If an application invokes 7308** any sqlite3_xxx API functions from within an unlock-notify callback, a 7309** crash or deadlock may be the result. 7310** 7311** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7312** returns SQLITE_OK. 7313** 7314** <b>Callback Invocation Details</b> 7315** 7316** When an unlock-notify callback is registered, the application provides a 7317** single void* pointer that is passed to the callback when it is invoked. 7318** However, the signature of the callback function allows SQLite to pass 7319** it an array of void* context pointers. The first argument passed to 7320** an unlock-notify callback is a pointer to an array of void* pointers, 7321** and the second is the number of entries in the array. 7322** 7323** When a blocking connections transaction is concluded, there may be 7324** more than one blocked connection that has registered for an unlock-notify 7325** callback. ^If two or more such blocked connections have specified the 7326** same callback function, then instead of invoking the callback function 7327** multiple times, it is invoked once with the set of void* context pointers 7328** specified by the blocked connections bundled together into an array. 7329** This gives the application an opportunity to prioritize any actions 7330** related to the set of unblocked database connections. 7331** 7332** <b>Deadlock Detection</b> 7333** 7334** Assuming that after registering for an unlock-notify callback a 7335** database waits for the callback to be issued before taking any further 7336** action (a reasonable assumption), then using this API may cause the 7337** application to deadlock. For example, if connection X is waiting for 7338** connection Y's transaction to be concluded, and similarly connection 7339** Y is waiting on connection X's transaction, then neither connection 7340** will proceed and the system may remain deadlocked indefinitely. 7341** 7342** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7343** detection. ^If a given call to sqlite3_unlock_notify() would put the 7344** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7345** unlock-notify callback is registered. The system is said to be in 7346** a deadlocked state if connection A has registered for an unlock-notify 7347** callback on the conclusion of connection B's transaction, and connection 7348** B has itself registered for an unlock-notify callback when connection 7349** A's transaction is concluded. ^Indirect deadlock is also detected, so 7350** the system is also considered to be deadlocked if connection B has 7351** registered for an unlock-notify callback on the conclusion of connection 7352** C's transaction, where connection C is waiting on connection A. ^Any 7353** number of levels of indirection are allowed. 7354** 7355** <b>The "DROP TABLE" Exception</b> 7356** 7357** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7358** always appropriate to call sqlite3_unlock_notify(). There is however, 7359** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7360** SQLite checks if there are any currently executing SELECT statements 7361** that belong to the same connection. If there are, SQLITE_LOCKED is 7362** returned. In this case there is no "blocking connection", so invoking 7363** sqlite3_unlock_notify() results in the unlock-notify callback being 7364** invoked immediately. If the application then re-attempts the "DROP TABLE" 7365** or "DROP INDEX" query, an infinite loop might be the result. 7366** 7367** One way around this problem is to check the extended error code returned 7368** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7369** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7370** the special "DROP TABLE/INDEX" case, the extended error code is just 7371** SQLITE_LOCKED.)^ 7372*/ 7373int sqlite3_unlock_notify( 7374 sqlite3 *pBlocked, /* Waiting connection */ 7375 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7376 void *pNotifyArg /* Argument to pass to xNotify */ 7377); 7378 7379 7380/* 7381** CAPI3REF: String Comparison 7382** 7383** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7384** and extensions to compare the contents of two buffers containing UTF-8 7385** strings in a case-independent fashion, using the same definition of "case 7386** independence" that SQLite uses internally when comparing identifiers. 7387*/ 7388int sqlite3_stricmp(const char *, const char *); 7389int sqlite3_strnicmp(const char *, const char *, int); 7390 7391/* 7392** CAPI3REF: String Globbing 7393* 7394** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7395** string X matches the [GLOB] pattern P. 7396** ^The definition of [GLOB] pattern matching used in 7397** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7398** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7399** is case sensitive. 7400** 7401** Note that this routine returns zero on a match and non-zero if the strings 7402** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7403** 7404** See also: [sqlite3_strlike()]. 7405*/ 7406int sqlite3_strglob(const char *zGlob, const char *zStr); 7407 7408/* 7409** CAPI3REF: String LIKE Matching 7410* 7411** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7412** string X matches the [LIKE] pattern P with escape character E. 7413** ^The definition of [LIKE] pattern matching used in 7414** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7415** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7416** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7417** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7418** insensitive - equivalent upper and lower case ASCII characters match 7419** one another. 7420** 7421** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7422** only ASCII characters are case folded. 7423** 7424** Note that this routine returns zero on a match and non-zero if the strings 7425** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7426** 7427** See also: [sqlite3_strglob()]. 7428*/ 7429int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7430 7431/* 7432** CAPI3REF: Error Logging Interface 7433** 7434** ^The [sqlite3_log()] interface writes a message into the [error log] 7435** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7436** ^If logging is enabled, the zFormat string and subsequent arguments are 7437** used with [sqlite3_snprintf()] to generate the final output string. 7438** 7439** The sqlite3_log() interface is intended for use by extensions such as 7440** virtual tables, collating functions, and SQL functions. While there is 7441** nothing to prevent an application from calling sqlite3_log(), doing so 7442** is considered bad form. 7443** 7444** The zFormat string must not be NULL. 7445** 7446** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7447** will not use dynamically allocated memory. The log message is stored in 7448** a fixed-length buffer on the stack. If the log message is longer than 7449** a few hundred characters, it will be truncated to the length of the 7450** buffer. 7451*/ 7452void sqlite3_log(int iErrCode, const char *zFormat, ...); 7453 7454/* 7455** CAPI3REF: Write-Ahead Log Commit Hook 7456** METHOD: sqlite3 7457** 7458** ^The [sqlite3_wal_hook()] function is used to register a callback that 7459** is invoked each time data is committed to a database in wal mode. 7460** 7461** ^(The callback is invoked by SQLite after the commit has taken place and 7462** the associated write-lock on the database released)^, so the implementation 7463** may read, write or [checkpoint] the database as required. 7464** 7465** ^The first parameter passed to the callback function when it is invoked 7466** is a copy of the third parameter passed to sqlite3_wal_hook() when 7467** registering the callback. ^The second is a copy of the database handle. 7468** ^The third parameter is the name of the database that was written to - 7469** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7470** is the number of pages currently in the write-ahead log file, 7471** including those that were just committed. 7472** 7473** The callback function should normally return [SQLITE_OK]. ^If an error 7474** code is returned, that error will propagate back up through the 7475** SQLite code base to cause the statement that provoked the callback 7476** to report an error, though the commit will have still occurred. If the 7477** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7478** that does not correspond to any valid SQLite error code, the results 7479** are undefined. 7480** 7481** A single database handle may have at most a single write-ahead log callback 7482** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7483** previously registered write-ahead log callback. ^Note that the 7484** [sqlite3_wal_autocheckpoint()] interface and the 7485** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7486** those overwrite any prior [sqlite3_wal_hook()] settings. 7487*/ 7488void *sqlite3_wal_hook( 7489 sqlite3*, 7490 int(*)(void *,sqlite3*,const char*,int), 7491 void* 7492); 7493 7494/* 7495** CAPI3REF: Configure an auto-checkpoint 7496** METHOD: sqlite3 7497** 7498** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 7499** [sqlite3_wal_hook()] that causes any database on [database connection] D 7500** to automatically [checkpoint] 7501** after committing a transaction if there are N or 7502** more frames in the [write-ahead log] file. ^Passing zero or 7503** a negative value as the nFrame parameter disables automatic 7504** checkpoints entirely. 7505** 7506** ^The callback registered by this function replaces any existing callback 7507** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 7508** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 7509** configured by this function. 7510** 7511** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 7512** from SQL. 7513** 7514** ^Checkpoints initiated by this mechanism are 7515** [sqlite3_wal_checkpoint_v2|PASSIVE]. 7516** 7517** ^Every new [database connection] defaults to having the auto-checkpoint 7518** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 7519** pages. The use of this interface 7520** is only necessary if the default setting is found to be suboptimal 7521** for a particular application. 7522*/ 7523int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 7524 7525/* 7526** CAPI3REF: Checkpoint a database 7527** METHOD: sqlite3 7528** 7529** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 7530** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 7531** 7532** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 7533** [write-ahead log] for database X on [database connection] D to be 7534** transferred into the database file and for the write-ahead log to 7535** be reset. See the [checkpointing] documentation for addition 7536** information. 7537** 7538** This interface used to be the only way to cause a checkpoint to 7539** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 7540** interface was added. This interface is retained for backwards 7541** compatibility and as a convenience for applications that need to manually 7542** start a callback but which do not need the full power (and corresponding 7543** complication) of [sqlite3_wal_checkpoint_v2()]. 7544*/ 7545int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 7546 7547/* 7548** CAPI3REF: Checkpoint a database 7549** METHOD: sqlite3 7550** 7551** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 7552** operation on database X of [database connection] D in mode M. Status 7553** information is written back into integers pointed to by L and C.)^ 7554** ^(The M parameter must be a valid [checkpoint mode]:)^ 7555** 7556** <dl> 7557** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7558** ^Checkpoint as many frames as possible without waiting for any database 7559** readers or writers to finish, then sync the database file if all frames 7560** in the log were checkpointed. ^The [busy-handler callback] 7561** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 7562** ^On the other hand, passive mode might leave the checkpoint unfinished 7563** if there are concurrent readers or writers. 7564** 7565** <dt>SQLITE_CHECKPOINT_FULL<dd> 7566** ^This mode blocks (it invokes the 7567** [sqlite3_busy_handler|busy-handler callback]) until there is no 7568** database writer and all readers are reading from the most recent database 7569** snapshot. ^It then checkpoints all frames in the log file and syncs the 7570** database file. ^This mode blocks new database writers while it is pending, 7571** but new database readers are allowed to continue unimpeded. 7572** 7573** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7574** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 7575** that after checkpointing the log file it blocks (calls the 7576** [busy-handler callback]) 7577** until all readers are reading from the database file only. ^This ensures 7578** that the next writer will restart the log file from the beginning. 7579** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 7580** database writer attempts while it is pending, but does not impede readers. 7581** 7582** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 7583** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 7584** addition that it also truncates the log file to zero bytes just prior 7585** to a successful return. 7586** </dl> 7587** 7588** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 7589** the log file or to -1 if the checkpoint could not run because 7590** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 7591** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 7592** log file (including any that were already checkpointed before the function 7593** was called) or to -1 if the checkpoint could not run due to an error or 7594** because the database is not in WAL mode. ^Note that upon successful 7595** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 7596** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 7597** 7598** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 7599** any other process is running a checkpoint operation at the same time, the 7600** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 7601** busy-handler configured, it will not be invoked in this case. 7602** 7603** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 7604** exclusive "writer" lock on the database file. ^If the writer lock cannot be 7605** obtained immediately, and a busy-handler is configured, it is invoked and 7606** the writer lock retried until either the busy-handler returns 0 or the lock 7607** is successfully obtained. ^The busy-handler is also invoked while waiting for 7608** database readers as described above. ^If the busy-handler returns 0 before 7609** the writer lock is obtained or while waiting for database readers, the 7610** checkpoint operation proceeds from that point in the same way as 7611** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7612** without blocking any further. ^SQLITE_BUSY is returned in this case. 7613** 7614** ^If parameter zDb is NULL or points to a zero length string, then the 7615** specified operation is attempted on all WAL databases [attached] to 7616** [database connection] db. In this case the 7617** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 7618** an SQLITE_BUSY error is encountered when processing one or more of the 7619** attached WAL databases, the operation is still attempted on any remaining 7620** attached databases and SQLITE_BUSY is returned at the end. ^If any other 7621** error occurs while processing an attached database, processing is abandoned 7622** and the error code is returned to the caller immediately. ^If no error 7623** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7624** databases, SQLITE_OK is returned. 7625** 7626** ^If database zDb is the name of an attached database that is not in WAL 7627** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 7628** zDb is not NULL (or a zero length string) and is not the name of any 7629** attached database, SQLITE_ERROR is returned to the caller. 7630** 7631** ^Unless it returns SQLITE_MISUSE, 7632** the sqlite3_wal_checkpoint_v2() interface 7633** sets the error information that is queried by 7634** [sqlite3_errcode()] and [sqlite3_errmsg()]. 7635** 7636** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 7637** from SQL. 7638*/ 7639int sqlite3_wal_checkpoint_v2( 7640 sqlite3 *db, /* Database handle */ 7641 const char *zDb, /* Name of attached database (or NULL) */ 7642 int eMode, /* SQLITE_CHECKPOINT_* value */ 7643 int *pnLog, /* OUT: Size of WAL log in frames */ 7644 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7645); 7646 7647/* 7648** CAPI3REF: Checkpoint Mode Values 7649** KEYWORDS: {checkpoint mode} 7650** 7651** These constants define all valid values for the "checkpoint mode" passed 7652** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 7653** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 7654** meaning of each of these checkpoint modes. 7655*/ 7656#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 7657#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 7658#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 7659#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 7660 7661/* 7662** CAPI3REF: Virtual Table Interface Configuration 7663** 7664** This function may be called by either the [xConnect] or [xCreate] method 7665** of a [virtual table] implementation to configure 7666** various facets of the virtual table interface. 7667** 7668** If this interface is invoked outside the context of an xConnect or 7669** xCreate virtual table method then the behavior is undefined. 7670** 7671** At present, there is only one option that may be configured using 7672** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7673** may be added in the future. 7674*/ 7675int sqlite3_vtab_config(sqlite3*, int op, ...); 7676 7677/* 7678** CAPI3REF: Virtual Table Configuration Options 7679** 7680** These macros define the various options to the 7681** [sqlite3_vtab_config()] interface that [virtual table] implementations 7682** can use to customize and optimize their behavior. 7683** 7684** <dl> 7685** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7686** <dd>Calls of the form 7687** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7688** where X is an integer. If X is zero, then the [virtual table] whose 7689** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7690** support constraints. In this configuration (which is the default) if 7691** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7692** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7693** specified as part of the users SQL statement, regardless of the actual 7694** ON CONFLICT mode specified. 7695** 7696** If X is non-zero, then the virtual table implementation guarantees 7697** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7698** any modifications to internal or persistent data structures have been made. 7699** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7700** is able to roll back a statement or database transaction, and abandon 7701** or continue processing the current SQL statement as appropriate. 7702** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7703** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7704** had been ABORT. 7705** 7706** Virtual table implementations that are required to handle OR REPLACE 7707** must do so within the [xUpdate] method. If a call to the 7708** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7709** CONFLICT policy is REPLACE, the virtual table implementation should 7710** silently replace the appropriate rows within the xUpdate callback and 7711** return SQLITE_OK. Or, if this is not possible, it may return 7712** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7713** constraint handling. 7714** </dl> 7715*/ 7716#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7717 7718/* 7719** CAPI3REF: Determine The Virtual Table Conflict Policy 7720** 7721** This function may only be called from within a call to the [xUpdate] method 7722** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7723** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7724** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7725** of the SQL statement that triggered the call to the [xUpdate] method of the 7726** [virtual table]. 7727*/ 7728int sqlite3_vtab_on_conflict(sqlite3 *); 7729 7730/* 7731** CAPI3REF: Conflict resolution modes 7732** KEYWORDS: {conflict resolution mode} 7733** 7734** These constants are returned by [sqlite3_vtab_on_conflict()] to 7735** inform a [virtual table] implementation what the [ON CONFLICT] mode 7736** is for the SQL statement being evaluated. 7737** 7738** Note that the [SQLITE_IGNORE] constant is also used as a potential 7739** return value from the [sqlite3_set_authorizer()] callback and that 7740** [SQLITE_ABORT] is also a [result code]. 7741*/ 7742#define SQLITE_ROLLBACK 1 7743/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7744#define SQLITE_FAIL 3 7745/* #define SQLITE_ABORT 4 // Also an error code */ 7746#define SQLITE_REPLACE 5 7747 7748/* 7749** CAPI3REF: Prepared Statement Scan Status Opcodes 7750** KEYWORDS: {scanstatus options} 7751** 7752** The following constants can be used for the T parameter to the 7753** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 7754** different metric for sqlite3_stmt_scanstatus() to return. 7755** 7756** When the value returned to V is a string, space to hold that string is 7757** managed by the prepared statement S and will be automatically freed when 7758** S is finalized. 7759** 7760** <dl> 7761** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 7762** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 7763** set to the total number of times that the X-th loop has run.</dd> 7764** 7765** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 7766** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 7767** to the total number of rows examined by all iterations of the X-th loop.</dd> 7768** 7769** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 7770** <dd>^The "double" variable pointed to by the T parameter will be set to the 7771** query planner's estimate for the average number of rows output from each 7772** iteration of the X-th loop. If the query planner's estimates was accurate, 7773** then this value will approximate the quotient NVISIT/NLOOP and the 7774** product of this value for all prior loops with the same SELECTID will 7775** be the NLOOP value for the current loop. 7776** 7777** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 7778** <dd>^The "const char *" variable pointed to by the T parameter will be set 7779** to a zero-terminated UTF-8 string containing the name of the index or table 7780** used for the X-th loop. 7781** 7782** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 7783** <dd>^The "const char *" variable pointed to by the T parameter will be set 7784** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 7785** description for the X-th loop. 7786** 7787** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 7788** <dd>^The "int" variable pointed to by the T parameter will be set to the 7789** "select-id" for the X-th loop. The select-id identifies which query or 7790** subquery the loop is part of. The main query has a select-id of zero. 7791** The select-id is the same value as is output in the first column 7792** of an [EXPLAIN QUERY PLAN] query. 7793** </dl> 7794*/ 7795#define SQLITE_SCANSTAT_NLOOP 0 7796#define SQLITE_SCANSTAT_NVISIT 1 7797#define SQLITE_SCANSTAT_EST 2 7798#define SQLITE_SCANSTAT_NAME 3 7799#define SQLITE_SCANSTAT_EXPLAIN 4 7800#define SQLITE_SCANSTAT_SELECTID 5 7801 7802/* 7803** CAPI3REF: Prepared Statement Scan Status 7804** METHOD: sqlite3_stmt 7805** 7806** This interface returns information about the predicted and measured 7807** performance for pStmt. Advanced applications can use this 7808** interface to compare the predicted and the measured performance and 7809** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 7810** 7811** Since this interface is expected to be rarely used, it is only 7812** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 7813** compile-time option. 7814** 7815** The "iScanStatusOp" parameter determines which status information to return. 7816** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 7817** of this interface is undefined. 7818** ^The requested measurement is written into a variable pointed to by 7819** the "pOut" parameter. 7820** Parameter "idx" identifies the specific loop to retrieve statistics for. 7821** Loops are numbered starting from zero. ^If idx is out of range - less than 7822** zero or greater than or equal to the total number of loops used to implement 7823** the statement - a non-zero value is returned and the variable that pOut 7824** points to is unchanged. 7825** 7826** ^Statistics might not be available for all loops in all statements. ^In cases 7827** where there exist loops with no available statistics, this function behaves 7828** as if the loop did not exist - it returns non-zero and leave the variable 7829** that pOut points to unchanged. 7830** 7831** See also: [sqlite3_stmt_scanstatus_reset()] 7832*/ 7833int sqlite3_stmt_scanstatus( 7834 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 7835 int idx, /* Index of loop to report on */ 7836 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 7837 void *pOut /* Result written here */ 7838); 7839 7840/* 7841** CAPI3REF: Zero Scan-Status Counters 7842** METHOD: sqlite3_stmt 7843** 7844** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 7845** 7846** This API is only available if the library is built with pre-processor 7847** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 7848*/ 7849void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 7850 7851/* 7852** CAPI3REF: Flush caches to disk mid-transaction 7853** 7854** ^If a write-transaction is open on [database connection] D when the 7855** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 7856** pages in the pager-cache that are not currently in use are written out 7857** to disk. A dirty page may be in use if a database cursor created by an 7858** active SQL statement is reading from it, or if it is page 1 of a database 7859** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 7860** interface flushes caches for all schemas - "main", "temp", and 7861** any [attached] databases. 7862** 7863** ^If this function needs to obtain extra database locks before dirty pages 7864** can be flushed to disk, it does so. ^If those locks cannot be obtained 7865** immediately and there is a busy-handler callback configured, it is invoked 7866** in the usual manner. ^If the required lock still cannot be obtained, then 7867** the database is skipped and an attempt made to flush any dirty pages 7868** belonging to the next (if any) database. ^If any databases are skipped 7869** because locks cannot be obtained, but no other error occurs, this 7870** function returns SQLITE_BUSY. 7871** 7872** ^If any other error occurs while flushing dirty pages to disk (for 7873** example an IO error or out-of-memory condition), then processing is 7874** abandoned and an SQLite [error code] is returned to the caller immediately. 7875** 7876** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 7877** 7878** ^This function does not set the database handle error code or message 7879** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 7880*/ 7881int sqlite3_db_cacheflush(sqlite3*); 7882 7883/* 7884** CAPI3REF: Database Snapshot 7885** KEYWORDS: {snapshot} 7886** EXPERIMENTAL 7887** 7888** An instance of the snapshot object records the state of a [WAL mode] 7889** database for some specific point in history. 7890** 7891** In [WAL mode], multiple [database connections] that are open on the 7892** same database file can each be reading a different historical version 7893** of the database file. When a [database connection] begins a read 7894** transaction, that connection sees an unchanging copy of the database 7895** as it existed for the point in time when the transaction first started. 7896** Subsequent changes to the database from other connections are not seen 7897** by the reader until a new read transaction is started. 7898** 7899** The sqlite3_snapshot object records state information about an historical 7900** version of the database file so that it is possible to later open a new read 7901** transaction that sees that historical version of the database rather than 7902** the most recent version. 7903** 7904** The constructor for this object is [sqlite3_snapshot_get()]. The 7905** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 7906** to an historical snapshot (if possible). The destructor for 7907** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 7908*/ 7909typedef struct sqlite3_snapshot sqlite3_snapshot; 7910 7911/* 7912** CAPI3REF: Record A Database Snapshot 7913** EXPERIMENTAL 7914** 7915** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 7916** new [sqlite3_snapshot] object that records the current state of 7917** schema S in database connection D. ^On success, the 7918** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 7919** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 7920** ^If schema S of [database connection] D is not a [WAL mode] database 7921** that is in a read transaction, then [sqlite3_snapshot_get(D,S,P)] 7922** leaves the *P value unchanged and returns an appropriate [error code]. 7923** 7924** The [sqlite3_snapshot] object returned from a successful call to 7925** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 7926** to avoid a memory leak. 7927** 7928** The [sqlite3_snapshot_get()] interface is only available when the 7929** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 7930*/ 7931SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 7932 sqlite3 *db, 7933 const char *zSchema, 7934 sqlite3_snapshot **ppSnapshot 7935); 7936 7937/* 7938** CAPI3REF: Start a read transaction on an historical snapshot 7939** EXPERIMENTAL 7940** 7941** ^The [sqlite3_snapshot_open(D,S,P)] interface attempts to move the 7942** read transaction that is currently open on schema S of 7943** [database connection] D so that it refers to historical [snapshot] P. 7944** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 7945** or an appropriate [error code] if it fails. 7946** 7947** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 7948** the first operation, apart from other sqlite3_snapshot_open() calls, 7949** following the [BEGIN] that starts a new read transaction. 7950** ^A [snapshot] will fail to open if it has been overwritten by a 7951** [checkpoint]. 7952** 7953** The [sqlite3_snapshot_open()] interface is only available when the 7954** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 7955*/ 7956SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 7957 sqlite3 *db, 7958 const char *zSchema, 7959 sqlite3_snapshot *pSnapshot 7960); 7961 7962/* 7963** CAPI3REF: Destroy a snapshot 7964** EXPERIMENTAL 7965** 7966** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 7967** The application must eventually free every [sqlite3_snapshot] object 7968** using this routine to avoid a memory leak. 7969** 7970** The [sqlite3_snapshot_free()] interface is only available when the 7971** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 7972*/ 7973SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 7974 7975/* 7976** Undo the hack that converts floating point types to integer for 7977** builds on processors without floating point support. 7978*/ 7979#ifdef SQLITE_OMIT_FLOATING_POINT 7980# undef double 7981#endif 7982 7983#ifdef __cplusplus 7984} /* End of the 'extern "C"' block */ 7985#endif 7986#endif /* _SQLITE3_H_ */ 7987