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** 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 also [SQLITE_FCNTL_JOURNAL_POINTER]. 798** 799** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 800** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 801** to the [sqlite3_file] object associated with the journal file (either 802** the [rollback journal] or the [write-ahead log]) for a particular database 803** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 804** 805** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 806** No longer in use. 807** 808** <li>[[SQLITE_FCNTL_SYNC]] 809** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 810** sent to the VFS immediately before the xSync method is invoked on a 811** database file descriptor. Or, if the xSync method is not invoked 812** because the user has configured SQLite with 813** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 814** of the xSync method. In most cases, the pointer argument passed with 815** this file-control is NULL. However, if the database file is being synced 816** as part of a multi-database commit, the argument points to a nul-terminated 817** string containing the transactions master-journal file name. VFSes that 818** do not need this signal should silently ignore this opcode. Applications 819** should not call [sqlite3_file_control()] with this opcode as doing so may 820** disrupt the operation of the specialized VFSes that do require it. 821** 822** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 823** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 824** and sent to the VFS after a transaction has been committed immediately 825** but before the database is unlocked. VFSes that do not need this signal 826** should silently ignore this opcode. Applications should not call 827** [sqlite3_file_control()] with this opcode as doing so may disrupt the 828** operation of the specialized VFSes that do require it. 829** 830** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 831** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 832** retry counts and intervals for certain disk I/O operations for the 833** windows [VFS] in order to provide robustness in the presence of 834** anti-virus programs. By default, the windows VFS will retry file read, 835** file write, and file delete operations up to 10 times, with a delay 836** of 25 milliseconds before the first retry and with the delay increasing 837** by an additional 25 milliseconds with each subsequent retry. This 838** opcode allows these two values (10 retries and 25 milliseconds of delay) 839** to be adjusted. The values are changed for all database connections 840** within the same process. The argument is a pointer to an array of two 841** integers where the first integer i the new retry count and the second 842** integer is the delay. If either integer is negative, then the setting 843** is not changed but instead the prior value of that setting is written 844** into the array entry, allowing the current retry settings to be 845** interrogated. The zDbName parameter is ignored. 846** 847** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 848** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 849** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 850** write ahead log and shared memory files used for transaction control 851** are automatically deleted when the latest connection to the database 852** closes. Setting persistent WAL mode causes those files to persist after 853** close. Persisting the files is useful when other processes that do not 854** have write permission on the directory containing the database file want 855** to read the database file, as the WAL and shared memory files must exist 856** in order for the database to be readable. The fourth parameter to 857** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 858** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 859** WAL mode. If the integer is -1, then it is overwritten with the current 860** WAL persistence setting. 861** 862** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 863** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 864** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 865** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 866** xDeviceCharacteristics methods. The fourth parameter to 867** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 868** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 869** mode. If the integer is -1, then it is overwritten with the current 870** zero-damage mode setting. 871** 872** <li>[[SQLITE_FCNTL_OVERWRITE]] 873** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 874** a write transaction to indicate that, unless it is rolled back for some 875** reason, the entire database file will be overwritten by the current 876** transaction. This is used by VACUUM operations. 877** 878** <li>[[SQLITE_FCNTL_VFSNAME]] 879** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 880** all [VFSes] in the VFS stack. The names are of all VFS shims and the 881** final bottom-level VFS are written into memory obtained from 882** [sqlite3_malloc()] and the result is stored in the char* variable 883** that the fourth parameter of [sqlite3_file_control()] points to. 884** The caller is responsible for freeing the memory when done. As with 885** all file-control actions, there is no guarantee that this will actually 886** do anything. Callers should initialize the char* variable to a NULL 887** pointer in case this file-control is not implemented. This file-control 888** is intended for diagnostic use only. 889** 890** <li>[[SQLITE_FCNTL_VFS_POINTER]] 891** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 892** [VFSes] currently in use. ^(The argument X in 893** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 894** of type "[sqlite3_vfs] **". This opcodes will set *X 895** to a pointer to the top-level VFS.)^ 896** ^When there are multiple VFS shims in the stack, this opcode finds the 897** upper-most shim only. 898** 899** <li>[[SQLITE_FCNTL_PRAGMA]] 900** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 901** file control is sent to the open [sqlite3_file] object corresponding 902** to the database file to which the pragma statement refers. ^The argument 903** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 904** pointers to strings (char**) in which the second element of the array 905** is the name of the pragma and the third element is the argument to the 906** pragma or NULL if the pragma has no argument. ^The handler for an 907** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 908** of the char** argument point to a string obtained from [sqlite3_mprintf()] 909** or the equivalent and that string will become the result of the pragma or 910** the error message if the pragma fails. ^If the 911** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 912** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 913** file control returns [SQLITE_OK], then the parser assumes that the 914** VFS has handled the PRAGMA itself and the parser generates a no-op 915** prepared statement if result string is NULL, or that returns a copy 916** of the result string if the string is non-NULL. 917** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 918** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 919** that the VFS encountered an error while handling the [PRAGMA] and the 920** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 921** file control occurs at the beginning of pragma statement analysis and so 922** it is able to override built-in [PRAGMA] statements. 923** 924** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 925** ^The [SQLITE_FCNTL_BUSYHANDLER] 926** file-control may be invoked by SQLite on the database file handle 927** shortly after it is opened in order to provide a custom VFS with access 928** to the connections busy-handler callback. The argument is of type (void **) 929** - an array of two (void *) values. The first (void *) actually points 930** to a function of type (int (*)(void *)). In order to invoke the connections 931** busy-handler, this function should be invoked with the second (void *) in 932** the array as the only argument. If it returns non-zero, then the operation 933** should be retried. If it returns zero, the custom VFS should abandon the 934** current operation. 935** 936** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 937** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 938** to have SQLite generate a 939** temporary filename using the same algorithm that is followed to generate 940** temporary filenames for TEMP tables and other internal uses. The 941** argument should be a char** which will be filled with the filename 942** written into memory obtained from [sqlite3_malloc()]. The caller should 943** invoke [sqlite3_free()] on the result to avoid a memory leak. 944** 945** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 946** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 947** maximum number of bytes that will be used for memory-mapped I/O. 948** The argument is a pointer to a value of type sqlite3_int64 that 949** is an advisory maximum number of bytes in the file to memory map. The 950** pointer is overwritten with the old value. The limit is not changed if 951** the value originally pointed to is negative, and so the current limit 952** can be queried by passing in a pointer to a negative number. This 953** file-control is used internally to implement [PRAGMA mmap_size]. 954** 955** <li>[[SQLITE_FCNTL_TRACE]] 956** The [SQLITE_FCNTL_TRACE] file control provides advisory information 957** to the VFS about what the higher layers of the SQLite stack are doing. 958** This file control is used by some VFS activity tracing [shims]. 959** The argument is a zero-terminated string. Higher layers in the 960** SQLite stack may generate instances of this file control if 961** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 962** 963** <li>[[SQLITE_FCNTL_HAS_MOVED]] 964** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 965** pointer to an integer and it writes a boolean into that integer depending 966** on whether or not the file has been renamed, moved, or deleted since it 967** was first opened. 968** 969** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 970** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 971** opcode causes the xFileControl method to swap the file handle with the one 972** pointed to by the pArg argument. This capability is used during testing 973** and only needs to be supported when SQLITE_TEST is defined. 974** 975** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 976** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 977** be advantageous to block on the next WAL lock if the lock is not immediately 978** available. The WAL subsystem issues this signal during rare 979** circumstances in order to fix a problem with priority inversion. 980** Applications should <em>not</em> use this file-control. 981** 982** <li>[[SQLITE_FCNTL_ZIPVFS]] 983** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 984** VFS should return SQLITE_NOTFOUND for this opcode. 985** 986** <li>[[SQLITE_FCNTL_RBU]] 987** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 988** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 989** this opcode. 990** </ul> 991*/ 992#define SQLITE_FCNTL_LOCKSTATE 1 993#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 994#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 995#define SQLITE_FCNTL_LAST_ERRNO 4 996#define SQLITE_FCNTL_SIZE_HINT 5 997#define SQLITE_FCNTL_CHUNK_SIZE 6 998#define SQLITE_FCNTL_FILE_POINTER 7 999#define SQLITE_FCNTL_SYNC_OMITTED 8 1000#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1001#define SQLITE_FCNTL_PERSIST_WAL 10 1002#define SQLITE_FCNTL_OVERWRITE 11 1003#define SQLITE_FCNTL_VFSNAME 12 1004#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1005#define SQLITE_FCNTL_PRAGMA 14 1006#define SQLITE_FCNTL_BUSYHANDLER 15 1007#define SQLITE_FCNTL_TEMPFILENAME 16 1008#define SQLITE_FCNTL_MMAP_SIZE 18 1009#define SQLITE_FCNTL_TRACE 19 1010#define SQLITE_FCNTL_HAS_MOVED 20 1011#define SQLITE_FCNTL_SYNC 21 1012#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1013#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1014#define SQLITE_FCNTL_WAL_BLOCK 24 1015#define SQLITE_FCNTL_ZIPVFS 25 1016#define SQLITE_FCNTL_RBU 26 1017#define SQLITE_FCNTL_VFS_POINTER 27 1018#define SQLITE_FCNTL_JOURNAL_POINTER 28 1019 1020/* deprecated names */ 1021#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1022#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1023#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1024 1025 1026/* 1027** CAPI3REF: Mutex Handle 1028** 1029** The mutex module within SQLite defines [sqlite3_mutex] to be an 1030** abstract type for a mutex object. The SQLite core never looks 1031** at the internal representation of an [sqlite3_mutex]. It only 1032** deals with pointers to the [sqlite3_mutex] object. 1033** 1034** Mutexes are created using [sqlite3_mutex_alloc()]. 1035*/ 1036typedef struct sqlite3_mutex sqlite3_mutex; 1037 1038/* 1039** CAPI3REF: OS Interface Object 1040** 1041** An instance of the sqlite3_vfs object defines the interface between 1042** the SQLite core and the underlying operating system. The "vfs" 1043** in the name of the object stands for "virtual file system". See 1044** the [VFS | VFS documentation] for further information. 1045** 1046** The value of the iVersion field is initially 1 but may be larger in 1047** future versions of SQLite. Additional fields may be appended to this 1048** object when the iVersion value is increased. Note that the structure 1049** of the sqlite3_vfs object changes in the transaction between 1050** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1051** modified. 1052** 1053** The szOsFile field is the size of the subclassed [sqlite3_file] 1054** structure used by this VFS. mxPathname is the maximum length of 1055** a pathname in this VFS. 1056** 1057** Registered sqlite3_vfs objects are kept on a linked list formed by 1058** the pNext pointer. The [sqlite3_vfs_register()] 1059** and [sqlite3_vfs_unregister()] interfaces manage this list 1060** in a thread-safe way. The [sqlite3_vfs_find()] interface 1061** searches the list. Neither the application code nor the VFS 1062** implementation should use the pNext pointer. 1063** 1064** The pNext field is the only field in the sqlite3_vfs 1065** structure that SQLite will ever modify. SQLite will only access 1066** or modify this field while holding a particular static mutex. 1067** The application should never modify anything within the sqlite3_vfs 1068** object once the object has been registered. 1069** 1070** The zName field holds the name of the VFS module. The name must 1071** be unique across all VFS modules. 1072** 1073** [[sqlite3_vfs.xOpen]] 1074** ^SQLite guarantees that the zFilename parameter to xOpen 1075** is either a NULL pointer or string obtained 1076** from xFullPathname() with an optional suffix added. 1077** ^If a suffix is added to the zFilename parameter, it will 1078** consist of a single "-" character followed by no more than 1079** 11 alphanumeric and/or "-" characters. 1080** ^SQLite further guarantees that 1081** the string will be valid and unchanged until xClose() is 1082** called. Because of the previous sentence, 1083** the [sqlite3_file] can safely store a pointer to the 1084** filename if it needs to remember the filename for some reason. 1085** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1086** must invent its own temporary name for the file. ^Whenever the 1087** xFilename parameter is NULL it will also be the case that the 1088** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1089** 1090** The flags argument to xOpen() includes all bits set in 1091** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1092** or [sqlite3_open16()] is used, then flags includes at least 1093** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1094** If xOpen() opens a file read-only then it sets *pOutFlags to 1095** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1096** 1097** ^(SQLite will also add one of the following flags to the xOpen() 1098** call, depending on the object being opened: 1099** 1100** <ul> 1101** <li> [SQLITE_OPEN_MAIN_DB] 1102** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1103** <li> [SQLITE_OPEN_TEMP_DB] 1104** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1105** <li> [SQLITE_OPEN_TRANSIENT_DB] 1106** <li> [SQLITE_OPEN_SUBJOURNAL] 1107** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1108** <li> [SQLITE_OPEN_WAL] 1109** </ul>)^ 1110** 1111** The file I/O implementation can use the object type flags to 1112** change the way it deals with files. For example, an application 1113** that does not care about crash recovery or rollback might make 1114** the open of a journal file a no-op. Writes to this journal would 1115** also be no-ops, and any attempt to read the journal would return 1116** SQLITE_IOERR. Or the implementation might recognize that a database 1117** file will be doing page-aligned sector reads and writes in a random 1118** order and set up its I/O subsystem accordingly. 1119** 1120** SQLite might also add one of the following flags to the xOpen method: 1121** 1122** <ul> 1123** <li> [SQLITE_OPEN_DELETEONCLOSE] 1124** <li> [SQLITE_OPEN_EXCLUSIVE] 1125** </ul> 1126** 1127** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1128** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1129** will be set for TEMP databases and their journals, transient 1130** databases, and subjournals. 1131** 1132** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1133** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1134** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1135** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1136** SQLITE_OPEN_CREATE, is used to indicate that file should always 1137** be created, and that it is an error if it already exists. 1138** It is <i>not</i> used to indicate the file should be opened 1139** for exclusive access. 1140** 1141** ^At least szOsFile bytes of memory are allocated by SQLite 1142** to hold the [sqlite3_file] structure passed as the third 1143** argument to xOpen. The xOpen method does not have to 1144** allocate the structure; it should just fill it in. Note that 1145** the xOpen method must set the sqlite3_file.pMethods to either 1146** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1147** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1148** element will be valid after xOpen returns regardless of the success 1149** or failure of the xOpen call. 1150** 1151** [[sqlite3_vfs.xAccess]] 1152** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1153** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1154** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1155** to test whether a file is at least readable. The file can be a 1156** directory. 1157** 1158** ^SQLite will always allocate at least mxPathname+1 bytes for the 1159** output buffer xFullPathname. The exact size of the output buffer 1160** is also passed as a parameter to both methods. If the output buffer 1161** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1162** handled as a fatal error by SQLite, vfs implementations should endeavor 1163** to prevent this by setting mxPathname to a sufficiently large value. 1164** 1165** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1166** interfaces are not strictly a part of the filesystem, but they are 1167** included in the VFS structure for completeness. 1168** The xRandomness() function attempts to return nBytes bytes 1169** of good-quality randomness into zOut. The return value is 1170** the actual number of bytes of randomness obtained. 1171** The xSleep() method causes the calling thread to sleep for at 1172** least the number of microseconds given. ^The xCurrentTime() 1173** method returns a Julian Day Number for the current date and time as 1174** a floating point value. 1175** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1176** Day Number multiplied by 86400000 (the number of milliseconds in 1177** a 24-hour day). 1178** ^SQLite will use the xCurrentTimeInt64() method to get the current 1179** date and time if that method is available (if iVersion is 2 or 1180** greater and the function pointer is not NULL) and will fall back 1181** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1182** 1183** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1184** are not used by the SQLite core. These optional interfaces are provided 1185** by some VFSes to facilitate testing of the VFS code. By overriding 1186** system calls with functions under its control, a test program can 1187** simulate faults and error conditions that would otherwise be difficult 1188** or impossible to induce. The set of system calls that can be overridden 1189** varies from one VFS to another, and from one version of the same VFS to the 1190** next. Applications that use these interfaces must be prepared for any 1191** or all of these interfaces to be NULL or for their behavior to change 1192** from one release to the next. Applications must not attempt to access 1193** any of these methods if the iVersion of the VFS is less than 3. 1194*/ 1195typedef struct sqlite3_vfs sqlite3_vfs; 1196typedef void (*sqlite3_syscall_ptr)(void); 1197struct sqlite3_vfs { 1198 int iVersion; /* Structure version number (currently 3) */ 1199 int szOsFile; /* Size of subclassed sqlite3_file */ 1200 int mxPathname; /* Maximum file pathname length */ 1201 sqlite3_vfs *pNext; /* Next registered VFS */ 1202 const char *zName; /* Name of this virtual file system */ 1203 void *pAppData; /* Pointer to application-specific data */ 1204 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1205 int flags, int *pOutFlags); 1206 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1207 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1208 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1209 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1210 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1211 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1212 void (*xDlClose)(sqlite3_vfs*, void*); 1213 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1214 int (*xSleep)(sqlite3_vfs*, int microseconds); 1215 int (*xCurrentTime)(sqlite3_vfs*, double*); 1216 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1217 /* 1218 ** The methods above are in version 1 of the sqlite_vfs object 1219 ** definition. Those that follow are added in version 2 or later 1220 */ 1221 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1222 /* 1223 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1224 ** Those below are for version 3 and greater. 1225 */ 1226 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1227 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1228 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1229 /* 1230 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1231 ** New fields may be appended in figure versions. The iVersion 1232 ** value will increment whenever this happens. 1233 */ 1234}; 1235 1236/* 1237** CAPI3REF: Flags for the xAccess VFS method 1238** 1239** These integer constants can be used as the third parameter to 1240** the xAccess method of an [sqlite3_vfs] object. They determine 1241** what kind of permissions the xAccess method is looking for. 1242** With SQLITE_ACCESS_EXISTS, the xAccess method 1243** simply checks whether the file exists. 1244** With SQLITE_ACCESS_READWRITE, the xAccess method 1245** checks whether the named directory is both readable and writable 1246** (in other words, if files can be added, removed, and renamed within 1247** the directory). 1248** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1249** [temp_store_directory pragma], though this could change in a future 1250** release of SQLite. 1251** With SQLITE_ACCESS_READ, the xAccess method 1252** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1253** currently unused, though it might be used in a future release of 1254** SQLite. 1255*/ 1256#define SQLITE_ACCESS_EXISTS 0 1257#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1258#define SQLITE_ACCESS_READ 2 /* Unused */ 1259 1260/* 1261** CAPI3REF: Flags for the xShmLock VFS method 1262** 1263** These integer constants define the various locking operations 1264** allowed by the xShmLock method of [sqlite3_io_methods]. The 1265** following are the only legal combinations of flags to the 1266** xShmLock method: 1267** 1268** <ul> 1269** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1270** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1271** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1272** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1273** </ul> 1274** 1275** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1276** was given on the corresponding lock. 1277** 1278** The xShmLock method can transition between unlocked and SHARED or 1279** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1280** and EXCLUSIVE. 1281*/ 1282#define SQLITE_SHM_UNLOCK 1 1283#define SQLITE_SHM_LOCK 2 1284#define SQLITE_SHM_SHARED 4 1285#define SQLITE_SHM_EXCLUSIVE 8 1286 1287/* 1288** CAPI3REF: Maximum xShmLock index 1289** 1290** The xShmLock method on [sqlite3_io_methods] may use values 1291** between 0 and this upper bound as its "offset" argument. 1292** The SQLite core will never attempt to acquire or release a 1293** lock outside of this range 1294*/ 1295#define SQLITE_SHM_NLOCK 8 1296 1297 1298/* 1299** CAPI3REF: Initialize The SQLite Library 1300** 1301** ^The sqlite3_initialize() routine initializes the 1302** SQLite library. ^The sqlite3_shutdown() routine 1303** deallocates any resources that were allocated by sqlite3_initialize(). 1304** These routines are designed to aid in process initialization and 1305** shutdown on embedded systems. Workstation applications using 1306** SQLite normally do not need to invoke either of these routines. 1307** 1308** A call to sqlite3_initialize() is an "effective" call if it is 1309** the first time sqlite3_initialize() is invoked during the lifetime of 1310** the process, or if it is the first time sqlite3_initialize() is invoked 1311** following a call to sqlite3_shutdown(). ^(Only an effective call 1312** of sqlite3_initialize() does any initialization. All other calls 1313** are harmless no-ops.)^ 1314** 1315** A call to sqlite3_shutdown() is an "effective" call if it is the first 1316** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1317** an effective call to sqlite3_shutdown() does any deinitialization. 1318** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1319** 1320** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1321** is not. The sqlite3_shutdown() interface must only be called from a 1322** single thread. All open [database connections] must be closed and all 1323** other SQLite resources must be deallocated prior to invoking 1324** sqlite3_shutdown(). 1325** 1326** Among other things, ^sqlite3_initialize() will invoke 1327** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1328** will invoke sqlite3_os_end(). 1329** 1330** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1331** ^If for some reason, sqlite3_initialize() is unable to initialize 1332** the library (perhaps it is unable to allocate a needed resource such 1333** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1334** 1335** ^The sqlite3_initialize() routine is called internally by many other 1336** SQLite interfaces so that an application usually does not need to 1337** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1338** calls sqlite3_initialize() so the SQLite library will be automatically 1339** initialized when [sqlite3_open()] is called if it has not be initialized 1340** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1341** compile-time option, then the automatic calls to sqlite3_initialize() 1342** are omitted and the application must call sqlite3_initialize() directly 1343** prior to using any other SQLite interface. For maximum portability, 1344** it is recommended that applications always invoke sqlite3_initialize() 1345** directly prior to using any other SQLite interface. Future releases 1346** of SQLite may require this. In other words, the behavior exhibited 1347** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1348** default behavior in some future release of SQLite. 1349** 1350** The sqlite3_os_init() routine does operating-system specific 1351** initialization of the SQLite library. The sqlite3_os_end() 1352** routine undoes the effect of sqlite3_os_init(). Typical tasks 1353** performed by these routines include allocation or deallocation 1354** of static resources, initialization of global variables, 1355** setting up a default [sqlite3_vfs] module, or setting up 1356** a default configuration using [sqlite3_config()]. 1357** 1358** The application should never invoke either sqlite3_os_init() 1359** or sqlite3_os_end() directly. The application should only invoke 1360** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1361** interface is called automatically by sqlite3_initialize() and 1362** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1363** implementations for sqlite3_os_init() and sqlite3_os_end() 1364** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1365** When [custom builds | built for other platforms] 1366** (using the [SQLITE_OS_OTHER=1] compile-time 1367** option) the application must supply a suitable implementation for 1368** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1369** implementation of sqlite3_os_init() or sqlite3_os_end() 1370** must return [SQLITE_OK] on success and some other [error code] upon 1371** failure. 1372*/ 1373int sqlite3_initialize(void); 1374int sqlite3_shutdown(void); 1375int sqlite3_os_init(void); 1376int sqlite3_os_end(void); 1377 1378/* 1379** CAPI3REF: Configuring The SQLite Library 1380** 1381** The sqlite3_config() interface is used to make global configuration 1382** changes to SQLite in order to tune SQLite to the specific needs of 1383** the application. The default configuration is recommended for most 1384** applications and so this routine is usually not necessary. It is 1385** provided to support rare applications with unusual needs. 1386** 1387** <b>The sqlite3_config() interface is not threadsafe. The application 1388** must ensure that no other SQLite interfaces are invoked by other 1389** threads while sqlite3_config() is running.</b> 1390** 1391** The sqlite3_config() interface 1392** may only be invoked prior to library initialization using 1393** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1394** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1395** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1396** Note, however, that ^sqlite3_config() can be called as part of the 1397** implementation of an application-defined [sqlite3_os_init()]. 1398** 1399** The first argument to sqlite3_config() is an integer 1400** [configuration option] that determines 1401** what property of SQLite is to be configured. Subsequent arguments 1402** vary depending on the [configuration option] 1403** in the first argument. 1404** 1405** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1406** ^If the option is unknown or SQLite is unable to set the option 1407** then this routine returns a non-zero [error code]. 1408*/ 1409int sqlite3_config(int, ...); 1410 1411/* 1412** CAPI3REF: Configure database connections 1413** METHOD: sqlite3 1414** 1415** The sqlite3_db_config() interface is used to make configuration 1416** changes to a [database connection]. The interface is similar to 1417** [sqlite3_config()] except that the changes apply to a single 1418** [database connection] (specified in the first argument). 1419** 1420** The second argument to sqlite3_db_config(D,V,...) is the 1421** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1422** that indicates what aspect of the [database connection] is being configured. 1423** Subsequent arguments vary depending on the configuration verb. 1424** 1425** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1426** the call is considered successful. 1427*/ 1428int sqlite3_db_config(sqlite3*, int op, ...); 1429 1430/* 1431** CAPI3REF: Memory Allocation Routines 1432** 1433** An instance of this object defines the interface between SQLite 1434** and low-level memory allocation routines. 1435** 1436** This object is used in only one place in the SQLite interface. 1437** A pointer to an instance of this object is the argument to 1438** [sqlite3_config()] when the configuration option is 1439** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1440** By creating an instance of this object 1441** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1442** during configuration, an application can specify an alternative 1443** memory allocation subsystem for SQLite to use for all of its 1444** dynamic memory needs. 1445** 1446** Note that SQLite comes with several [built-in memory allocators] 1447** that are perfectly adequate for the overwhelming majority of applications 1448** and that this object is only useful to a tiny minority of applications 1449** with specialized memory allocation requirements. This object is 1450** also used during testing of SQLite in order to specify an alternative 1451** memory allocator that simulates memory out-of-memory conditions in 1452** order to verify that SQLite recovers gracefully from such 1453** conditions. 1454** 1455** The xMalloc, xRealloc, and xFree methods must work like the 1456** malloc(), realloc() and free() functions from the standard C library. 1457** ^SQLite guarantees that the second argument to 1458** xRealloc is always a value returned by a prior call to xRoundup. 1459** 1460** xSize should return the allocated size of a memory allocation 1461** previously obtained from xMalloc or xRealloc. The allocated size 1462** is always at least as big as the requested size but may be larger. 1463** 1464** The xRoundup method returns what would be the allocated size of 1465** a memory allocation given a particular requested size. Most memory 1466** allocators round up memory allocations at least to the next multiple 1467** of 8. Some allocators round up to a larger multiple or to a power of 2. 1468** Every memory allocation request coming in through [sqlite3_malloc()] 1469** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1470** that causes the corresponding memory allocation to fail. 1471** 1472** The xInit method initializes the memory allocator. For example, 1473** it might allocate any require mutexes or initialize internal data 1474** structures. The xShutdown method is invoked (indirectly) by 1475** [sqlite3_shutdown()] and should deallocate any resources acquired 1476** by xInit. The pAppData pointer is used as the only parameter to 1477** xInit and xShutdown. 1478** 1479** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1480** the xInit method, so the xInit method need not be threadsafe. The 1481** xShutdown method is only called from [sqlite3_shutdown()] so it does 1482** not need to be threadsafe either. For all other methods, SQLite 1483** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1484** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1485** it is by default) and so the methods are automatically serialized. 1486** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1487** methods must be threadsafe or else make their own arrangements for 1488** serialization. 1489** 1490** SQLite will never invoke xInit() more than once without an intervening 1491** call to xShutdown(). 1492*/ 1493typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1494struct sqlite3_mem_methods { 1495 void *(*xMalloc)(int); /* Memory allocation function */ 1496 void (*xFree)(void*); /* Free a prior allocation */ 1497 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1498 int (*xSize)(void*); /* Return the size of an allocation */ 1499 int (*xRoundup)(int); /* Round up request size to allocation size */ 1500 int (*xInit)(void*); /* Initialize the memory allocator */ 1501 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1502 void *pAppData; /* Argument to xInit() and xShutdown() */ 1503}; 1504 1505/* 1506** CAPI3REF: Configuration Options 1507** KEYWORDS: {configuration option} 1508** 1509** These constants are the available integer configuration options that 1510** can be passed as the first argument to the [sqlite3_config()] interface. 1511** 1512** New configuration options may be added in future releases of SQLite. 1513** Existing configuration options might be discontinued. Applications 1514** should check the return code from [sqlite3_config()] to make sure that 1515** the call worked. The [sqlite3_config()] interface will return a 1516** non-zero [error code] if a discontinued or unsupported configuration option 1517** is invoked. 1518** 1519** <dl> 1520** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1521** <dd>There are no arguments to this option. ^This option sets the 1522** [threading mode] to Single-thread. In other words, it disables 1523** all mutexing and puts SQLite into a mode where it can only be used 1524** by a single thread. ^If SQLite is compiled with 1525** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1526** it is not possible to change the [threading mode] from its default 1527** value of Single-thread and so [sqlite3_config()] will return 1528** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1529** configuration option.</dd> 1530** 1531** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1532** <dd>There are no arguments to this option. ^This option sets the 1533** [threading mode] to Multi-thread. In other words, it disables 1534** mutexing on [database connection] and [prepared statement] objects. 1535** The application is responsible for serializing access to 1536** [database connections] and [prepared statements]. But other mutexes 1537** are enabled so that SQLite will be safe to use in a multi-threaded 1538** environment as long as no two threads attempt to use the same 1539** [database connection] at the same time. ^If SQLite is compiled with 1540** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1541** it is not possible to set the Multi-thread [threading mode] and 1542** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1543** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1544** 1545** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1546** <dd>There are no arguments to this option. ^This option sets the 1547** [threading mode] to Serialized. In other words, this option enables 1548** all mutexes including the recursive 1549** mutexes on [database connection] and [prepared statement] objects. 1550** In this mode (which is the default when SQLite is compiled with 1551** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1552** to [database connections] and [prepared statements] so that the 1553** application is free to use the same [database connection] or the 1554** same [prepared statement] in different threads at the same time. 1555** ^If SQLite is compiled with 1556** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1557** it is not possible to set the Serialized [threading mode] and 1558** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1559** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1560** 1561** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1562** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1563** a pointer to an instance of the [sqlite3_mem_methods] structure. 1564** The argument specifies 1565** alternative low-level memory allocation routines to be used in place of 1566** the memory allocation routines built into SQLite.)^ ^SQLite makes 1567** its own private copy of the content of the [sqlite3_mem_methods] structure 1568** before the [sqlite3_config()] call returns.</dd> 1569** 1570** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1571** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1572** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1573** The [sqlite3_mem_methods] 1574** structure is filled with the currently defined memory allocation routines.)^ 1575** This option can be used to overload the default memory allocation 1576** routines with a wrapper that simulations memory allocation failure or 1577** tracks memory usage, for example. </dd> 1578** 1579** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1580** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1581** interpreted as a boolean, which enables or disables the collection of 1582** memory allocation statistics. ^(When memory allocation statistics are 1583** disabled, the following SQLite interfaces become non-operational: 1584** <ul> 1585** <li> [sqlite3_memory_used()] 1586** <li> [sqlite3_memory_highwater()] 1587** <li> [sqlite3_soft_heap_limit64()] 1588** <li> [sqlite3_status64()] 1589** </ul>)^ 1590** ^Memory allocation statistics are enabled by default unless SQLite is 1591** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1592** allocation statistics are disabled by default. 1593** </dd> 1594** 1595** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1596** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer 1597** that SQLite can use for scratch memory. ^(There are three arguments 1598** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte 1599** aligned memory buffer from which the scratch allocations will be 1600** drawn, the size of each scratch allocation (sz), 1601** and the maximum number of scratch allocations (N).)^ 1602** The first argument must be a pointer to an 8-byte aligned buffer 1603** of at least sz*N bytes of memory. 1604** ^SQLite will not use more than one scratch buffers per thread. 1605** ^SQLite will never request a scratch buffer that is more than 6 1606** times the database page size. 1607** ^If SQLite needs needs additional 1608** scratch memory beyond what is provided by this configuration option, then 1609** [sqlite3_malloc()] will be used to obtain the memory needed.<p> 1610** ^When the application provides any amount of scratch memory using 1611** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large 1612** [sqlite3_malloc|heap allocations]. 1613** This can help [Robson proof|prevent memory allocation failures] due to heap 1614** fragmentation in low-memory embedded systems. 1615** </dd> 1616** 1617** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1618** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1619** that SQLite can use for the database page cache with the default page 1620** cache implementation. 1621** This configuration option is a no-op if an application-define page 1622** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1623** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1624** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1625** and the number of cache lines (N). 1626** The sz argument should be the size of the largest database page 1627** (a power of two between 512 and 65536) plus some extra bytes for each 1628** page header. ^The number of extra bytes needed by the page header 1629** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1630** ^It is harmless, apart from the wasted memory, 1631** for the sz parameter to be larger than necessary. The pMem 1632** argument must be either a NULL pointer or a pointer to an 8-byte 1633** aligned block of memory of at least sz*N bytes, otherwise 1634** subsequent behavior is undefined. 1635** ^When pMem is not NULL, SQLite will strive to use the memory provided 1636** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1637** a page cache line is larger than sz bytes or if all of the pMem buffer 1638** is exhausted. 1639** ^If pMem is NULL and N is non-zero, then each database connection 1640** does an initial bulk allocation for page cache memory 1641** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1642** of -1024*N bytes if N is negative, . ^If additional 1643** page cache memory is needed beyond what is provided by the initial 1644** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1645** additional cache line. </dd> 1646** 1647** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1648** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1649** that SQLite will use for all of its dynamic memory allocation needs 1650** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and 1651** [SQLITE_CONFIG_PAGECACHE]. 1652** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1653** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1654** [SQLITE_ERROR] if invoked otherwise. 1655** ^There are three arguments to SQLITE_CONFIG_HEAP: 1656** An 8-byte aligned pointer to the memory, 1657** the number of bytes in the memory buffer, and the minimum allocation size. 1658** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1659** to using its default memory allocator (the system malloc() implementation), 1660** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1661** memory pointer is not NULL then the alternative memory 1662** allocator is engaged to handle all of SQLites memory allocation needs. 1663** The first pointer (the memory pointer) must be aligned to an 8-byte 1664** boundary or subsequent behavior of SQLite will be undefined. 1665** The minimum allocation size is capped at 2**12. Reasonable values 1666** for the minimum allocation size are 2**5 through 2**8.</dd> 1667** 1668** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1669** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1670** pointer to an instance of the [sqlite3_mutex_methods] structure. 1671** The argument specifies alternative low-level mutex routines to be used 1672** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1673** the content of the [sqlite3_mutex_methods] structure before the call to 1674** [sqlite3_config()] returns. ^If SQLite is compiled with 1675** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1676** the entire mutexing subsystem is omitted from the build and hence calls to 1677** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1678** return [SQLITE_ERROR].</dd> 1679** 1680** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1681** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1682** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1683** [sqlite3_mutex_methods] 1684** structure is filled with the currently defined mutex routines.)^ 1685** This option can be used to overload the default mutex allocation 1686** routines with a wrapper used to track mutex usage for performance 1687** profiling or testing, for example. ^If SQLite is compiled with 1688** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1689** the entire mutexing subsystem is omitted from the build and hence calls to 1690** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1691** return [SQLITE_ERROR].</dd> 1692** 1693** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1694** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1695** the default size of lookaside memory on each [database connection]. 1696** The first argument is the 1697** size of each lookaside buffer slot and the second is the number of 1698** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1699** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1700** option to [sqlite3_db_config()] can be used to change the lookaside 1701** configuration on individual connections.)^ </dd> 1702** 1703** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1704** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1705** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1706** the interface to a custom page cache implementation.)^ 1707** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1708** 1709** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1710** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1711** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1712** the current page cache implementation into that object.)^ </dd> 1713** 1714** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1715** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1716** global [error log]. 1717** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1718** function with a call signature of void(*)(void*,int,const char*), 1719** and a pointer to void. ^If the function pointer is not NULL, it is 1720** invoked by [sqlite3_log()] to process each logging event. ^If the 1721** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1722** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1723** passed through as the first parameter to the application-defined logger 1724** function whenever that function is invoked. ^The second parameter to 1725** the logger function is a copy of the first parameter to the corresponding 1726** [sqlite3_log()] call and is intended to be a [result code] or an 1727** [extended result code]. ^The third parameter passed to the logger is 1728** log message after formatting via [sqlite3_snprintf()]. 1729** The SQLite logging interface is not reentrant; the logger function 1730** supplied by the application must not invoke any SQLite interface. 1731** In a multi-threaded application, the application-defined logger 1732** function must be threadsafe. </dd> 1733** 1734** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1735** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1736** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1737** then URI handling is globally disabled.)^ ^If URI handling is globally 1738** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1739** [sqlite3_open16()] or 1740** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1741** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1742** connection is opened. ^If it is globally disabled, filenames are 1743** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1744** database connection is opened. ^(By default, URI handling is globally 1745** disabled. The default value may be changed by compiling with the 1746** [SQLITE_USE_URI] symbol defined.)^ 1747** 1748** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1749** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1750** argument which is interpreted as a boolean in order to enable or disable 1751** the use of covering indices for full table scans in the query optimizer. 1752** ^The default setting is determined 1753** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1754** if that compile-time option is omitted. 1755** The ability to disable the use of covering indices for full table scans 1756** is because some incorrectly coded legacy applications might malfunction 1757** when the optimization is enabled. Providing the ability to 1758** disable the optimization allows the older, buggy application code to work 1759** without change even with newer versions of SQLite. 1760** 1761** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1762** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1763** <dd> These options are obsolete and should not be used by new code. 1764** They are retained for backwards compatibility but are now no-ops. 1765** </dd> 1766** 1767** [[SQLITE_CONFIG_SQLLOG]] 1768** <dt>SQLITE_CONFIG_SQLLOG 1769** <dd>This option is only available if sqlite is compiled with the 1770** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1771** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1772** The second should be of type (void*). The callback is invoked by the library 1773** in three separate circumstances, identified by the value passed as the 1774** fourth parameter. If the fourth parameter is 0, then the database connection 1775** passed as the second argument has just been opened. The third argument 1776** points to a buffer containing the name of the main database file. If the 1777** fourth parameter is 1, then the SQL statement that the third parameter 1778** points to has just been executed. Or, if the fourth parameter is 2, then 1779** the connection being passed as the second parameter is being closed. The 1780** third parameter is passed NULL In this case. An example of using this 1781** configuration option can be seen in the "test_sqllog.c" source file in 1782** the canonical SQLite source tree.</dd> 1783** 1784** [[SQLITE_CONFIG_MMAP_SIZE]] 1785** <dt>SQLITE_CONFIG_MMAP_SIZE 1786** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1787** that are the default mmap size limit (the default setting for 1788** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1789** ^The default setting can be overridden by each database connection using 1790** either the [PRAGMA mmap_size] command, or by using the 1791** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1792** will be silently truncated if necessary so that it does not exceed the 1793** compile-time maximum mmap size set by the 1794** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1795** ^If either argument to this option is negative, then that argument is 1796** changed to its compile-time default. 1797** 1798** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1799** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1800** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1801** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1802** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1803** that specifies the maximum size of the created heap. 1804** 1805** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1806** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1807** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1808** is a pointer to an integer and writes into that integer the number of extra 1809** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1810** The amount of extra space required can change depending on the compiler, 1811** target platform, and SQLite version. 1812** 1813** [[SQLITE_CONFIG_PMASZ]] 1814** <dt>SQLITE_CONFIG_PMASZ 1815** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1816** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1817** sorter to that integer. The default minimum PMA Size is set by the 1818** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1819** to help with sort operations when multithreaded sorting 1820** is enabled (using the [PRAGMA threads] command) and the amount of content 1821** to be sorted exceeds the page size times the minimum of the 1822** [PRAGMA cache_size] setting and this value. 1823** </dl> 1824*/ 1825#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1826#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1827#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1828#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1829#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1830#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1831#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1832#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1833#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1834#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1835#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1836/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1837#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1838#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1839#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1840#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1841#define SQLITE_CONFIG_URI 17 /* int */ 1842#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1843#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1844#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1845#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1846#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1847#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1848#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1849#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1850 1851/* 1852** CAPI3REF: Database Connection Configuration Options 1853** 1854** These constants are the available integer configuration options that 1855** can be passed as the second argument to the [sqlite3_db_config()] interface. 1856** 1857** New configuration options may be added in future releases of SQLite. 1858** Existing configuration options might be discontinued. Applications 1859** should check the return code from [sqlite3_db_config()] to make sure that 1860** the call worked. ^The [sqlite3_db_config()] interface will return a 1861** non-zero [error code] if a discontinued or unsupported configuration option 1862** is invoked. 1863** 1864** <dl> 1865** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1866** <dd> ^This option takes three additional arguments that determine the 1867** [lookaside memory allocator] configuration for the [database connection]. 1868** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1869** pointer to a memory buffer to use for lookaside memory. 1870** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1871** may be NULL in which case SQLite will allocate the 1872** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1873** size of each lookaside buffer slot. ^The third argument is the number of 1874** slots. The size of the buffer in the first argument must be greater than 1875** or equal to the product of the second and third arguments. The buffer 1876** must be aligned to an 8-byte boundary. ^If the second argument to 1877** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1878** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1879** configuration for a database connection can only be changed when that 1880** connection is not currently using lookaside memory, or in other words 1881** when the "current value" returned by 1882** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1883** Any attempt to change the lookaside memory configuration when lookaside 1884** memory is in use leaves the configuration unchanged and returns 1885** [SQLITE_BUSY].)^</dd> 1886** 1887** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1888** <dd> ^This option is used to enable or disable the enforcement of 1889** [foreign key constraints]. There should be two additional arguments. 1890** The first argument is an integer which is 0 to disable FK enforcement, 1891** positive to enable FK enforcement or negative to leave FK enforcement 1892** unchanged. The second parameter is a pointer to an integer into which 1893** is written 0 or 1 to indicate whether FK enforcement is off or on 1894** following this call. The second parameter may be a NULL pointer, in 1895** which case the FK enforcement setting is not reported back. </dd> 1896** 1897** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1898** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1899** There should be two additional arguments. 1900** The first argument is an integer which is 0 to disable triggers, 1901** positive to enable triggers or negative to leave the setting unchanged. 1902** The second parameter is a pointer to an integer into which 1903** is written 0 or 1 to indicate whether triggers are disabled or enabled 1904** following this call. The second parameter may be a NULL pointer, in 1905** which case the trigger setting is not reported back. </dd> 1906** 1907** </dl> 1908*/ 1909#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1910#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1911#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1912 1913 1914/* 1915** CAPI3REF: Enable Or Disable Extended Result Codes 1916** METHOD: sqlite3 1917** 1918** ^The sqlite3_extended_result_codes() routine enables or disables the 1919** [extended result codes] feature of SQLite. ^The extended result 1920** codes are disabled by default for historical compatibility. 1921*/ 1922int sqlite3_extended_result_codes(sqlite3*, int onoff); 1923 1924/* 1925** CAPI3REF: Last Insert Rowid 1926** METHOD: sqlite3 1927** 1928** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 1929** has a unique 64-bit signed 1930** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1931** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1932** names are not also used by explicitly declared columns. ^If 1933** the table has a column of type [INTEGER PRIMARY KEY] then that column 1934** is another alias for the rowid. 1935** 1936** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the 1937** most recent successful [INSERT] into a rowid table or [virtual table] 1938** on database connection D. 1939** ^Inserts into [WITHOUT ROWID] tables are not recorded. 1940** ^If no successful [INSERT]s into rowid tables 1941** have ever occurred on the database connection D, 1942** then sqlite3_last_insert_rowid(D) returns zero. 1943** 1944** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1945** method, then this routine will return the [rowid] of the inserted 1946** row as long as the trigger or virtual table method is running. 1947** But once the trigger or virtual table method ends, the value returned 1948** by this routine reverts to what it was before the trigger or virtual 1949** table method began.)^ 1950** 1951** ^An [INSERT] that fails due to a constraint violation is not a 1952** successful [INSERT] and does not change the value returned by this 1953** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1954** and INSERT OR ABORT make no changes to the return value of this 1955** routine when their insertion fails. ^(When INSERT OR REPLACE 1956** encounters a constraint violation, it does not fail. The 1957** INSERT continues to completion after deleting rows that caused 1958** the constraint problem so INSERT OR REPLACE will always change 1959** the return value of this interface.)^ 1960** 1961** ^For the purposes of this routine, an [INSERT] is considered to 1962** be successful even if it is subsequently rolled back. 1963** 1964** This function is accessible to SQL statements via the 1965** [last_insert_rowid() SQL function]. 1966** 1967** If a separate thread performs a new [INSERT] on the same 1968** database connection while the [sqlite3_last_insert_rowid()] 1969** function is running and thus changes the last insert [rowid], 1970** then the value returned by [sqlite3_last_insert_rowid()] is 1971** unpredictable and might not equal either the old or the new 1972** last insert [rowid]. 1973*/ 1974sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1975 1976/* 1977** CAPI3REF: Count The Number Of Rows Modified 1978** METHOD: sqlite3 1979** 1980** ^This function returns the number of rows modified, inserted or 1981** deleted by the most recently completed INSERT, UPDATE or DELETE 1982** statement on the database connection specified by the only parameter. 1983** ^Executing any other type of SQL statement does not modify the value 1984** returned by this function. 1985** 1986** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 1987** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 1988** [foreign key actions] or [REPLACE] constraint resolution are not counted. 1989** 1990** Changes to a view that are intercepted by 1991** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 1992** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 1993** DELETE statement run on a view is always zero. Only changes made to real 1994** tables are counted. 1995** 1996** Things are more complicated if the sqlite3_changes() function is 1997** executed while a trigger program is running. This may happen if the 1998** program uses the [changes() SQL function], or if some other callback 1999** function invokes sqlite3_changes() directly. Essentially: 2000** 2001** <ul> 2002** <li> ^(Before entering a trigger program the value returned by 2003** sqlite3_changes() function is saved. After the trigger program 2004** has finished, the original value is restored.)^ 2005** 2006** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2007** statement sets the value returned by sqlite3_changes() 2008** upon completion as normal. Of course, this value will not include 2009** any changes performed by sub-triggers, as the sqlite3_changes() 2010** value will be saved and restored after each sub-trigger has run.)^ 2011** </ul> 2012** 2013** ^This means that if the changes() SQL function (or similar) is used 2014** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2015** returns the value as set when the calling statement began executing. 2016** ^If it is used by the second or subsequent such statement within a trigger 2017** program, the value returned reflects the number of rows modified by the 2018** previous INSERT, UPDATE or DELETE statement within the same trigger. 2019** 2020** See also the [sqlite3_total_changes()] interface, the 2021** [count_changes pragma], and the [changes() SQL function]. 2022** 2023** If a separate thread makes changes on the same database connection 2024** while [sqlite3_changes()] is running then the value returned 2025** is unpredictable and not meaningful. 2026*/ 2027int sqlite3_changes(sqlite3*); 2028 2029/* 2030** CAPI3REF: Total Number Of Rows Modified 2031** METHOD: sqlite3 2032** 2033** ^This function returns the total number of rows inserted, modified or 2034** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2035** since the database connection was opened, including those executed as 2036** part of trigger programs. ^Executing any other type of SQL statement 2037** does not affect the value returned by sqlite3_total_changes(). 2038** 2039** ^Changes made as part of [foreign key actions] are included in the 2040** count, but those made as part of REPLACE constraint resolution are 2041** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2042** are not counted. 2043** 2044** See also the [sqlite3_changes()] interface, the 2045** [count_changes pragma], and the [total_changes() SQL function]. 2046** 2047** If a separate thread makes changes on the same database connection 2048** while [sqlite3_total_changes()] is running then the value 2049** returned is unpredictable and not meaningful. 2050*/ 2051int sqlite3_total_changes(sqlite3*); 2052 2053/* 2054** CAPI3REF: Interrupt A Long-Running Query 2055** METHOD: sqlite3 2056** 2057** ^This function causes any pending database operation to abort and 2058** return at its earliest opportunity. This routine is typically 2059** called in response to a user action such as pressing "Cancel" 2060** or Ctrl-C where the user wants a long query operation to halt 2061** immediately. 2062** 2063** ^It is safe to call this routine from a thread different from the 2064** thread that is currently running the database operation. But it 2065** is not safe to call this routine with a [database connection] that 2066** is closed or might close before sqlite3_interrupt() returns. 2067** 2068** ^If an SQL operation is very nearly finished at the time when 2069** sqlite3_interrupt() is called, then it might not have an opportunity 2070** to be interrupted and might continue to completion. 2071** 2072** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2073** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2074** that is inside an explicit transaction, then the entire transaction 2075** will be rolled back automatically. 2076** 2077** ^The sqlite3_interrupt(D) call is in effect until all currently running 2078** SQL statements on [database connection] D complete. ^Any new SQL statements 2079** that are started after the sqlite3_interrupt() call and before the 2080** running statements reaches zero are interrupted as if they had been 2081** running prior to the sqlite3_interrupt() call. ^New SQL statements 2082** that are started after the running statement count reaches zero are 2083** not effected by the sqlite3_interrupt(). 2084** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2085** SQL statements is a no-op and has no effect on SQL statements 2086** that are started after the sqlite3_interrupt() call returns. 2087** 2088** If the database connection closes while [sqlite3_interrupt()] 2089** is running then bad things will likely happen. 2090*/ 2091void sqlite3_interrupt(sqlite3*); 2092 2093/* 2094** CAPI3REF: Determine If An SQL Statement Is Complete 2095** 2096** These routines are useful during command-line input to determine if the 2097** currently entered text seems to form a complete SQL statement or 2098** if additional input is needed before sending the text into 2099** SQLite for parsing. ^These routines return 1 if the input string 2100** appears to be a complete SQL statement. ^A statement is judged to be 2101** complete if it ends with a semicolon token and is not a prefix of a 2102** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2103** string literals or quoted identifier names or comments are not 2104** independent tokens (they are part of the token in which they are 2105** embedded) and thus do not count as a statement terminator. ^Whitespace 2106** and comments that follow the final semicolon are ignored. 2107** 2108** ^These routines return 0 if the statement is incomplete. ^If a 2109** memory allocation fails, then SQLITE_NOMEM is returned. 2110** 2111** ^These routines do not parse the SQL statements thus 2112** will not detect syntactically incorrect SQL. 2113** 2114** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2115** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2116** automatically by sqlite3_complete16(). If that initialization fails, 2117** then the return value from sqlite3_complete16() will be non-zero 2118** regardless of whether or not the input SQL is complete.)^ 2119** 2120** The input to [sqlite3_complete()] must be a zero-terminated 2121** UTF-8 string. 2122** 2123** The input to [sqlite3_complete16()] must be a zero-terminated 2124** UTF-16 string in native byte order. 2125*/ 2126int sqlite3_complete(const char *sql); 2127int sqlite3_complete16(const void *sql); 2128 2129/* 2130** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2131** KEYWORDS: {busy-handler callback} {busy handler} 2132** METHOD: sqlite3 2133** 2134** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2135** that might be invoked with argument P whenever 2136** an attempt is made to access a database table associated with 2137** [database connection] D when another thread 2138** or process has the table locked. 2139** The sqlite3_busy_handler() interface is used to implement 2140** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2141** 2142** ^If the busy callback is NULL, then [SQLITE_BUSY] 2143** is returned immediately upon encountering the lock. ^If the busy callback 2144** is not NULL, then the callback might be invoked with two arguments. 2145** 2146** ^The first argument to the busy handler is a copy of the void* pointer which 2147** is the third argument to sqlite3_busy_handler(). ^The second argument to 2148** the busy handler callback is the number of times that the busy handler has 2149** been invoked previously for the same locking event. ^If the 2150** busy callback returns 0, then no additional attempts are made to 2151** access the database and [SQLITE_BUSY] is returned 2152** to the application. 2153** ^If the callback returns non-zero, then another attempt 2154** is made to access the database and the cycle repeats. 2155** 2156** The presence of a busy handler does not guarantee that it will be invoked 2157** when there is lock contention. ^If SQLite determines that invoking the busy 2158** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2159** to the application instead of invoking the 2160** busy handler. 2161** Consider a scenario where one process is holding a read lock that 2162** it is trying to promote to a reserved lock and 2163** a second process is holding a reserved lock that it is trying 2164** to promote to an exclusive lock. The first process cannot proceed 2165** because it is blocked by the second and the second process cannot 2166** proceed because it is blocked by the first. If both processes 2167** invoke the busy handlers, neither will make any progress. Therefore, 2168** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2169** will induce the first process to release its read lock and allow 2170** the second process to proceed. 2171** 2172** ^The default busy callback is NULL. 2173** 2174** ^(There can only be a single busy handler defined for each 2175** [database connection]. Setting a new busy handler clears any 2176** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2177** or evaluating [PRAGMA busy_timeout=N] will change the 2178** busy handler and thus clear any previously set busy handler. 2179** 2180** The busy callback should not take any actions which modify the 2181** database connection that invoked the busy handler. In other words, 2182** the busy handler is not reentrant. Any such actions 2183** result in undefined behavior. 2184** 2185** A busy handler must not close the database connection 2186** or [prepared statement] that invoked the busy handler. 2187*/ 2188int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2189 2190/* 2191** CAPI3REF: Set A Busy Timeout 2192** METHOD: sqlite3 2193** 2194** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2195** for a specified amount of time when a table is locked. ^The handler 2196** will sleep multiple times until at least "ms" milliseconds of sleeping 2197** have accumulated. ^After at least "ms" milliseconds of sleeping, 2198** the handler returns 0 which causes [sqlite3_step()] to return 2199** [SQLITE_BUSY]. 2200** 2201** ^Calling this routine with an argument less than or equal to zero 2202** turns off all busy handlers. 2203** 2204** ^(There can only be a single busy handler for a particular 2205** [database connection] at any given moment. If another busy handler 2206** was defined (using [sqlite3_busy_handler()]) prior to calling 2207** this routine, that other busy handler is cleared.)^ 2208** 2209** See also: [PRAGMA busy_timeout] 2210*/ 2211int sqlite3_busy_timeout(sqlite3*, int ms); 2212 2213/* 2214** CAPI3REF: Convenience Routines For Running Queries 2215** METHOD: sqlite3 2216** 2217** This is a legacy interface that is preserved for backwards compatibility. 2218** Use of this interface is not recommended. 2219** 2220** Definition: A <b>result table</b> is memory data structure created by the 2221** [sqlite3_get_table()] interface. A result table records the 2222** complete query results from one or more queries. 2223** 2224** The table conceptually has a number of rows and columns. But 2225** these numbers are not part of the result table itself. These 2226** numbers are obtained separately. Let N be the number of rows 2227** and M be the number of columns. 2228** 2229** A result table is an array of pointers to zero-terminated UTF-8 strings. 2230** There are (N+1)*M elements in the array. The first M pointers point 2231** to zero-terminated strings that contain the names of the columns. 2232** The remaining entries all point to query results. NULL values result 2233** in NULL pointers. All other values are in their UTF-8 zero-terminated 2234** string representation as returned by [sqlite3_column_text()]. 2235** 2236** A result table might consist of one or more memory allocations. 2237** It is not safe to pass a result table directly to [sqlite3_free()]. 2238** A result table should be deallocated using [sqlite3_free_table()]. 2239** 2240** ^(As an example of the result table format, suppose a query result 2241** is as follows: 2242** 2243** <blockquote><pre> 2244** Name | Age 2245** ----------------------- 2246** Alice | 43 2247** Bob | 28 2248** Cindy | 21 2249** </pre></blockquote> 2250** 2251** There are two column (M==2) and three rows (N==3). Thus the 2252** result table has 8 entries. Suppose the result table is stored 2253** in an array names azResult. Then azResult holds this content: 2254** 2255** <blockquote><pre> 2256** azResult[0] = "Name"; 2257** azResult[1] = "Age"; 2258** azResult[2] = "Alice"; 2259** azResult[3] = "43"; 2260** azResult[4] = "Bob"; 2261** azResult[5] = "28"; 2262** azResult[6] = "Cindy"; 2263** azResult[7] = "21"; 2264** </pre></blockquote>)^ 2265** 2266** ^The sqlite3_get_table() function evaluates one or more 2267** semicolon-separated SQL statements in the zero-terminated UTF-8 2268** string of its 2nd parameter and returns a result table to the 2269** pointer given in its 3rd parameter. 2270** 2271** After the application has finished with the result from sqlite3_get_table(), 2272** it must pass the result table pointer to sqlite3_free_table() in order to 2273** release the memory that was malloced. Because of the way the 2274** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2275** function must not try to call [sqlite3_free()] directly. Only 2276** [sqlite3_free_table()] is able to release the memory properly and safely. 2277** 2278** The sqlite3_get_table() interface is implemented as a wrapper around 2279** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2280** to any internal data structures of SQLite. It uses only the public 2281** interface defined here. As a consequence, errors that occur in the 2282** wrapper layer outside of the internal [sqlite3_exec()] call are not 2283** reflected in subsequent calls to [sqlite3_errcode()] or 2284** [sqlite3_errmsg()]. 2285*/ 2286int sqlite3_get_table( 2287 sqlite3 *db, /* An open database */ 2288 const char *zSql, /* SQL to be evaluated */ 2289 char ***pazResult, /* Results of the query */ 2290 int *pnRow, /* Number of result rows written here */ 2291 int *pnColumn, /* Number of result columns written here */ 2292 char **pzErrmsg /* Error msg written here */ 2293); 2294void sqlite3_free_table(char **result); 2295 2296/* 2297** CAPI3REF: Formatted String Printing Functions 2298** 2299** These routines are work-alikes of the "printf()" family of functions 2300** from the standard C library. 2301** These routines understand most of the common K&R formatting options, 2302** plus some additional non-standard formats, detailed below. 2303** Note that some of the more obscure formatting options from recent 2304** C-library standards are omitted from this implementation. 2305** 2306** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2307** results into memory obtained from [sqlite3_malloc()]. 2308** The strings returned by these two routines should be 2309** released by [sqlite3_free()]. ^Both routines return a 2310** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2311** memory to hold the resulting string. 2312** 2313** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2314** the standard C library. The result is written into the 2315** buffer supplied as the second parameter whose size is given by 2316** the first parameter. Note that the order of the 2317** first two parameters is reversed from snprintf().)^ This is an 2318** historical accident that cannot be fixed without breaking 2319** backwards compatibility. ^(Note also that sqlite3_snprintf() 2320** returns a pointer to its buffer instead of the number of 2321** characters actually written into the buffer.)^ We admit that 2322** the number of characters written would be a more useful return 2323** value but we cannot change the implementation of sqlite3_snprintf() 2324** now without breaking compatibility. 2325** 2326** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2327** guarantees that the buffer is always zero-terminated. ^The first 2328** parameter "n" is the total size of the buffer, including space for 2329** the zero terminator. So the longest string that can be completely 2330** written will be n-1 characters. 2331** 2332** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2333** 2334** These routines all implement some additional formatting 2335** options that are useful for constructing SQL statements. 2336** All of the usual printf() formatting options apply. In addition, there 2337** is are "%q", "%Q", "%w" and "%z" options. 2338** 2339** ^(The %q option works like %s in that it substitutes a nul-terminated 2340** string from the argument list. But %q also doubles every '\'' character. 2341** %q is designed for use inside a string literal.)^ By doubling each '\'' 2342** character it escapes that character and allows it to be inserted into 2343** the string. 2344** 2345** For example, assume the string variable zText contains text as follows: 2346** 2347** <blockquote><pre> 2348** char *zText = "It's a happy day!"; 2349** </pre></blockquote> 2350** 2351** One can use this text in an SQL statement as follows: 2352** 2353** <blockquote><pre> 2354** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2355** sqlite3_exec(db, zSQL, 0, 0, 0); 2356** sqlite3_free(zSQL); 2357** </pre></blockquote> 2358** 2359** Because the %q format string is used, the '\'' character in zText 2360** is escaped and the SQL generated is as follows: 2361** 2362** <blockquote><pre> 2363** INSERT INTO table1 VALUES('It''s a happy day!') 2364** </pre></blockquote> 2365** 2366** This is correct. Had we used %s instead of %q, the generated SQL 2367** would have looked like this: 2368** 2369** <blockquote><pre> 2370** INSERT INTO table1 VALUES('It's a happy day!'); 2371** </pre></blockquote> 2372** 2373** This second example is an SQL syntax error. As a general rule you should 2374** always use %q instead of %s when inserting text into a string literal. 2375** 2376** ^(The %Q option works like %q except it also adds single quotes around 2377** the outside of the total string. Additionally, if the parameter in the 2378** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2379** single quotes).)^ So, for example, one could say: 2380** 2381** <blockquote><pre> 2382** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2383** sqlite3_exec(db, zSQL, 0, 0, 0); 2384** sqlite3_free(zSQL); 2385** </pre></blockquote> 2386** 2387** The code above will render a correct SQL statement in the zSQL 2388** variable even if the zText variable is a NULL pointer. 2389** 2390** ^(The "%w" formatting option is like "%q" except that it expects to 2391** be contained within double-quotes instead of single quotes, and it 2392** escapes the double-quote character instead of the single-quote 2393** character.)^ The "%w" formatting option is intended for safely inserting 2394** table and column names into a constructed SQL statement. 2395** 2396** ^(The "%z" formatting option works like "%s" but with the 2397** addition that after the string has been read and copied into 2398** the result, [sqlite3_free()] is called on the input string.)^ 2399*/ 2400char *sqlite3_mprintf(const char*,...); 2401char *sqlite3_vmprintf(const char*, va_list); 2402char *sqlite3_snprintf(int,char*,const char*, ...); 2403char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2404 2405/* 2406** CAPI3REF: Memory Allocation Subsystem 2407** 2408** The SQLite core uses these three routines for all of its own 2409** internal memory allocation needs. "Core" in the previous sentence 2410** does not include operating-system specific VFS implementation. The 2411** Windows VFS uses native malloc() and free() for some operations. 2412** 2413** ^The sqlite3_malloc() routine returns a pointer to a block 2414** of memory at least N bytes in length, where N is the parameter. 2415** ^If sqlite3_malloc() is unable to obtain sufficient free 2416** memory, it returns a NULL pointer. ^If the parameter N to 2417** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2418** a NULL pointer. 2419** 2420** ^The sqlite3_malloc64(N) routine works just like 2421** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2422** of a signed 32-bit integer. 2423** 2424** ^Calling sqlite3_free() with a pointer previously returned 2425** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2426** that it might be reused. ^The sqlite3_free() routine is 2427** a no-op if is called with a NULL pointer. Passing a NULL pointer 2428** to sqlite3_free() is harmless. After being freed, memory 2429** should neither be read nor written. Even reading previously freed 2430** memory might result in a segmentation fault or other severe error. 2431** Memory corruption, a segmentation fault, or other severe error 2432** might result if sqlite3_free() is called with a non-NULL pointer that 2433** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2434** 2435** ^The sqlite3_realloc(X,N) interface attempts to resize a 2436** prior memory allocation X to be at least N bytes. 2437** ^If the X parameter to sqlite3_realloc(X,N) 2438** is a NULL pointer then its behavior is identical to calling 2439** sqlite3_malloc(N). 2440** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2441** negative then the behavior is exactly the same as calling 2442** sqlite3_free(X). 2443** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2444** of at least N bytes in size or NULL if insufficient memory is available. 2445** ^If M is the size of the prior allocation, then min(N,M) bytes 2446** of the prior allocation are copied into the beginning of buffer returned 2447** by sqlite3_realloc(X,N) and the prior allocation is freed. 2448** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2449** prior allocation is not freed. 2450** 2451** ^The sqlite3_realloc64(X,N) interfaces works the same as 2452** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2453** of a 32-bit signed integer. 2454** 2455** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2456** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2457** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2458** ^The value returned by sqlite3_msize(X) might be larger than the number 2459** of bytes requested when X was allocated. ^If X is a NULL pointer then 2460** sqlite3_msize(X) returns zero. If X points to something that is not 2461** the beginning of memory allocation, or if it points to a formerly 2462** valid memory allocation that has now been freed, then the behavior 2463** of sqlite3_msize(X) is undefined and possibly harmful. 2464** 2465** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2466** sqlite3_malloc64(), and sqlite3_realloc64() 2467** is always aligned to at least an 8 byte boundary, or to a 2468** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2469** option is used. 2470** 2471** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2472** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2473** implementation of these routines to be omitted. That capability 2474** is no longer provided. Only built-in memory allocators can be used. 2475** 2476** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2477** the system malloc() and free() directly when converting 2478** filenames between the UTF-8 encoding used by SQLite 2479** and whatever filename encoding is used by the particular Windows 2480** installation. Memory allocation errors were detected, but 2481** they were reported back as [SQLITE_CANTOPEN] or 2482** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2483** 2484** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2485** must be either NULL or else pointers obtained from a prior 2486** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2487** not yet been released. 2488** 2489** The application must not read or write any part of 2490** a block of memory after it has been released using 2491** [sqlite3_free()] or [sqlite3_realloc()]. 2492*/ 2493void *sqlite3_malloc(int); 2494void *sqlite3_malloc64(sqlite3_uint64); 2495void *sqlite3_realloc(void*, int); 2496void *sqlite3_realloc64(void*, sqlite3_uint64); 2497void sqlite3_free(void*); 2498sqlite3_uint64 sqlite3_msize(void*); 2499 2500/* 2501** CAPI3REF: Memory Allocator Statistics 2502** 2503** SQLite provides these two interfaces for reporting on the status 2504** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2505** routines, which form the built-in memory allocation subsystem. 2506** 2507** ^The [sqlite3_memory_used()] routine returns the number of bytes 2508** of memory currently outstanding (malloced but not freed). 2509** ^The [sqlite3_memory_highwater()] routine returns the maximum 2510** value of [sqlite3_memory_used()] since the high-water mark 2511** was last reset. ^The values returned by [sqlite3_memory_used()] and 2512** [sqlite3_memory_highwater()] include any overhead 2513** added by SQLite in its implementation of [sqlite3_malloc()], 2514** but not overhead added by the any underlying system library 2515** routines that [sqlite3_malloc()] may call. 2516** 2517** ^The memory high-water mark is reset to the current value of 2518** [sqlite3_memory_used()] if and only if the parameter to 2519** [sqlite3_memory_highwater()] is true. ^The value returned 2520** by [sqlite3_memory_highwater(1)] is the high-water mark 2521** prior to the reset. 2522*/ 2523sqlite3_int64 sqlite3_memory_used(void); 2524sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2525 2526/* 2527** CAPI3REF: Pseudo-Random Number Generator 2528** 2529** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2530** select random [ROWID | ROWIDs] when inserting new records into a table that 2531** already uses the largest possible [ROWID]. The PRNG is also used for 2532** the build-in random() and randomblob() SQL functions. This interface allows 2533** applications to access the same PRNG for other purposes. 2534** 2535** ^A call to this routine stores N bytes of randomness into buffer P. 2536** ^The P parameter can be a NULL pointer. 2537** 2538** ^If this routine has not been previously called or if the previous 2539** call had N less than one or a NULL pointer for P, then the PRNG is 2540** seeded using randomness obtained from the xRandomness method of 2541** the default [sqlite3_vfs] object. 2542** ^If the previous call to this routine had an N of 1 or more and a 2543** non-NULL P then the pseudo-randomness is generated 2544** internally and without recourse to the [sqlite3_vfs] xRandomness 2545** method. 2546*/ 2547void sqlite3_randomness(int N, void *P); 2548 2549/* 2550** CAPI3REF: Compile-Time Authorization Callbacks 2551** METHOD: sqlite3 2552** 2553** ^This routine registers an authorizer callback with a particular 2554** [database connection], supplied in the first argument. 2555** ^The authorizer callback is invoked as SQL statements are being compiled 2556** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2557** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2558** points during the compilation process, as logic is being created 2559** to perform various actions, the authorizer callback is invoked to 2560** see if those actions are allowed. ^The authorizer callback should 2561** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2562** specific action but allow the SQL statement to continue to be 2563** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2564** rejected with an error. ^If the authorizer callback returns 2565** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2566** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2567** the authorizer will fail with an error message. 2568** 2569** When the callback returns [SQLITE_OK], that means the operation 2570** requested is ok. ^When the callback returns [SQLITE_DENY], the 2571** [sqlite3_prepare_v2()] or equivalent call that triggered the 2572** authorizer will fail with an error message explaining that 2573** access is denied. 2574** 2575** ^The first parameter to the authorizer callback is a copy of the third 2576** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2577** to the callback is an integer [SQLITE_COPY | action code] that specifies 2578** the particular action to be authorized. ^The third through sixth parameters 2579** to the callback are zero-terminated strings that contain additional 2580** details about the action to be authorized. 2581** 2582** ^If the action code is [SQLITE_READ] 2583** and the callback returns [SQLITE_IGNORE] then the 2584** [prepared statement] statement is constructed to substitute 2585** a NULL value in place of the table column that would have 2586** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2587** return can be used to deny an untrusted user access to individual 2588** columns of a table. 2589** ^If the action code is [SQLITE_DELETE] and the callback returns 2590** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2591** [truncate optimization] is disabled and all rows are deleted individually. 2592** 2593** An authorizer is used when [sqlite3_prepare | preparing] 2594** SQL statements from an untrusted source, to ensure that the SQL statements 2595** do not try to access data they are not allowed to see, or that they do not 2596** try to execute malicious statements that damage the database. For 2597** example, an application may allow a user to enter arbitrary 2598** SQL queries for evaluation by a database. But the application does 2599** not want the user to be able to make arbitrary changes to the 2600** database. An authorizer could then be put in place while the 2601** user-entered SQL is being [sqlite3_prepare | prepared] that 2602** disallows everything except [SELECT] statements. 2603** 2604** Applications that need to process SQL from untrusted sources 2605** might also consider lowering resource limits using [sqlite3_limit()] 2606** and limiting database size using the [max_page_count] [PRAGMA] 2607** in addition to using an authorizer. 2608** 2609** ^(Only a single authorizer can be in place on a database connection 2610** at a time. Each call to sqlite3_set_authorizer overrides the 2611** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2612** The authorizer is disabled by default. 2613** 2614** The authorizer callback must not do anything that will modify 2615** the database connection that invoked the authorizer callback. 2616** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2617** database connections for the meaning of "modify" in this paragraph. 2618** 2619** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2620** statement might be re-prepared during [sqlite3_step()] due to a 2621** schema change. Hence, the application should ensure that the 2622** correct authorizer callback remains in place during the [sqlite3_step()]. 2623** 2624** ^Note that the authorizer callback is invoked only during 2625** [sqlite3_prepare()] or its variants. Authorization is not 2626** performed during statement evaluation in [sqlite3_step()], unless 2627** as stated in the previous paragraph, sqlite3_step() invokes 2628** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2629*/ 2630int sqlite3_set_authorizer( 2631 sqlite3*, 2632 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2633 void *pUserData 2634); 2635 2636/* 2637** CAPI3REF: Authorizer Return Codes 2638** 2639** The [sqlite3_set_authorizer | authorizer callback function] must 2640** return either [SQLITE_OK] or one of these two constants in order 2641** to signal SQLite whether or not the action is permitted. See the 2642** [sqlite3_set_authorizer | authorizer documentation] for additional 2643** information. 2644** 2645** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2646** returned from the [sqlite3_vtab_on_conflict()] interface. 2647*/ 2648#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2649#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2650 2651/* 2652** CAPI3REF: Authorizer Action Codes 2653** 2654** The [sqlite3_set_authorizer()] interface registers a callback function 2655** that is invoked to authorize certain SQL statement actions. The 2656** second parameter to the callback is an integer code that specifies 2657** what action is being authorized. These are the integer action codes that 2658** the authorizer callback may be passed. 2659** 2660** These action code values signify what kind of operation is to be 2661** authorized. The 3rd and 4th parameters to the authorization 2662** callback function will be parameters or NULL depending on which of these 2663** codes is used as the second parameter. ^(The 5th parameter to the 2664** authorizer callback is the name of the database ("main", "temp", 2665** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2666** is the name of the inner-most trigger or view that is responsible for 2667** the access attempt or NULL if this access attempt is directly from 2668** top-level SQL code. 2669*/ 2670/******************************************* 3rd ************ 4th ***********/ 2671#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2672#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2673#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2674#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2675#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2676#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2677#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2678#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2679#define SQLITE_DELETE 9 /* Table Name NULL */ 2680#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2681#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2682#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2683#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2684#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2685#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2686#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2687#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2688#define SQLITE_INSERT 18 /* Table Name NULL */ 2689#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2690#define SQLITE_READ 20 /* Table Name Column Name */ 2691#define SQLITE_SELECT 21 /* NULL NULL */ 2692#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2693#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2694#define SQLITE_ATTACH 24 /* Filename NULL */ 2695#define SQLITE_DETACH 25 /* Database Name NULL */ 2696#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2697#define SQLITE_REINDEX 27 /* Index Name NULL */ 2698#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2699#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2700#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2701#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2702#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2703#define SQLITE_COPY 0 /* No longer used */ 2704#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2705 2706/* 2707** CAPI3REF: Tracing And Profiling Functions 2708** METHOD: sqlite3 2709** 2710** These routines register callback functions that can be used for 2711** tracing and profiling the execution of SQL statements. 2712** 2713** ^The callback function registered by sqlite3_trace() is invoked at 2714** various times when an SQL statement is being run by [sqlite3_step()]. 2715** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2716** SQL statement text as the statement first begins executing. 2717** ^(Additional sqlite3_trace() callbacks might occur 2718** as each triggered subprogram is entered. The callbacks for triggers 2719** contain a UTF-8 SQL comment that identifies the trigger.)^ 2720** 2721** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2722** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2723** 2724** ^The callback function registered by sqlite3_profile() is invoked 2725** as each SQL statement finishes. ^The profile callback contains 2726** the original statement text and an estimate of wall-clock time 2727** of how long that statement took to run. ^The profile callback 2728** time is in units of nanoseconds, however the current implementation 2729** is only capable of millisecond resolution so the six least significant 2730** digits in the time are meaningless. Future versions of SQLite 2731** might provide greater resolution on the profiler callback. The 2732** sqlite3_profile() function is considered experimental and is 2733** subject to change in future versions of SQLite. 2734*/ 2735void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2736SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2737 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2738 2739/* 2740** CAPI3REF: Query Progress Callbacks 2741** METHOD: sqlite3 2742** 2743** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2744** function X to be invoked periodically during long running calls to 2745** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2746** database connection D. An example use for this 2747** interface is to keep a GUI updated during a large query. 2748** 2749** ^The parameter P is passed through as the only parameter to the 2750** callback function X. ^The parameter N is the approximate number of 2751** [virtual machine instructions] that are evaluated between successive 2752** invocations of the callback X. ^If N is less than one then the progress 2753** handler is disabled. 2754** 2755** ^Only a single progress handler may be defined at one time per 2756** [database connection]; setting a new progress handler cancels the 2757** old one. ^Setting parameter X to NULL disables the progress handler. 2758** ^The progress handler is also disabled by setting N to a value less 2759** than 1. 2760** 2761** ^If the progress callback returns non-zero, the operation is 2762** interrupted. This feature can be used to implement a 2763** "Cancel" button on a GUI progress dialog box. 2764** 2765** The progress handler callback must not do anything that will modify 2766** the database connection that invoked the progress handler. 2767** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2768** database connections for the meaning of "modify" in this paragraph. 2769** 2770*/ 2771void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2772 2773/* 2774** CAPI3REF: Opening A New Database Connection 2775** CONSTRUCTOR: sqlite3 2776** 2777** ^These routines open an SQLite database file as specified by the 2778** filename argument. ^The filename argument is interpreted as UTF-8 for 2779** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2780** order for sqlite3_open16(). ^(A [database connection] handle is usually 2781** returned in *ppDb, even if an error occurs. The only exception is that 2782** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2783** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2784** object.)^ ^(If the database is opened (and/or created) successfully, then 2785** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2786** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2787** an English language description of the error following a failure of any 2788** of the sqlite3_open() routines. 2789** 2790** ^The default encoding will be UTF-8 for databases created using 2791** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 2792** created using sqlite3_open16() will be UTF-16 in the native byte order. 2793** 2794** Whether or not an error occurs when it is opened, resources 2795** associated with the [database connection] handle should be released by 2796** passing it to [sqlite3_close()] when it is no longer required. 2797** 2798** The sqlite3_open_v2() interface works like sqlite3_open() 2799** except that it accepts two additional parameters for additional control 2800** over the new database connection. ^(The flags parameter to 2801** sqlite3_open_v2() can take one of 2802** the following three values, optionally combined with the 2803** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2804** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2805** 2806** <dl> 2807** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2808** <dd>The database is opened in read-only mode. If the database does not 2809** already exist, an error is returned.</dd>)^ 2810** 2811** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2812** <dd>The database is opened for reading and writing if possible, or reading 2813** only if the file is write protected by the operating system. In either 2814** case the database must already exist, otherwise an error is returned.</dd>)^ 2815** 2816** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2817** <dd>The database is opened for reading and writing, and is created if 2818** it does not already exist. This is the behavior that is always used for 2819** sqlite3_open() and sqlite3_open16().</dd>)^ 2820** </dl> 2821** 2822** If the 3rd parameter to sqlite3_open_v2() is not one of the 2823** combinations shown above optionally combined with other 2824** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2825** then the behavior is undefined. 2826** 2827** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2828** opens in the multi-thread [threading mode] as long as the single-thread 2829** mode has not been set at compile-time or start-time. ^If the 2830** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2831** in the serialized [threading mode] unless single-thread was 2832** previously selected at compile-time or start-time. 2833** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2834** eligible to use [shared cache mode], regardless of whether or not shared 2835** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2836** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2837** participate in [shared cache mode] even if it is enabled. 2838** 2839** ^The fourth parameter to sqlite3_open_v2() is the name of the 2840** [sqlite3_vfs] object that defines the operating system interface that 2841** the new database connection should use. ^If the fourth parameter is 2842** a NULL pointer then the default [sqlite3_vfs] object is used. 2843** 2844** ^If the filename is ":memory:", then a private, temporary in-memory database 2845** is created for the connection. ^This in-memory database will vanish when 2846** the database connection is closed. Future versions of SQLite might 2847** make use of additional special filenames that begin with the ":" character. 2848** It is recommended that when a database filename actually does begin with 2849** a ":" character you should prefix the filename with a pathname such as 2850** "./" to avoid ambiguity. 2851** 2852** ^If the filename is an empty string, then a private, temporary 2853** on-disk database will be created. ^This private database will be 2854** automatically deleted as soon as the database connection is closed. 2855** 2856** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2857** 2858** ^If [URI filename] interpretation is enabled, and the filename argument 2859** begins with "file:", then the filename is interpreted as a URI. ^URI 2860** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2861** set in the fourth argument to sqlite3_open_v2(), or if it has 2862** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2863** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2864** As of SQLite version 3.7.7, URI filename interpretation is turned off 2865** by default, but future releases of SQLite might enable URI filename 2866** interpretation by default. See "[URI filenames]" for additional 2867** information. 2868** 2869** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2870** authority, then it must be either an empty string or the string 2871** "localhost". ^If the authority is not an empty string or "localhost", an 2872** error is returned to the caller. ^The fragment component of a URI, if 2873** present, is ignored. 2874** 2875** ^SQLite uses the path component of the URI as the name of the disk file 2876** which contains the database. ^If the path begins with a '/' character, 2877** then it is interpreted as an absolute path. ^If the path does not begin 2878** with a '/' (meaning that the authority section is omitted from the URI) 2879** then the path is interpreted as a relative path. 2880** ^(On windows, the first component of an absolute path 2881** is a drive specification (e.g. "C:").)^ 2882** 2883** [[core URI query parameters]] 2884** The query component of a URI may contain parameters that are interpreted 2885** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2886** SQLite and its built-in [VFSes] interpret the 2887** following query parameters: 2888** 2889** <ul> 2890** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2891** a VFS object that provides the operating system interface that should 2892** be used to access the database file on disk. ^If this option is set to 2893** an empty string the default VFS object is used. ^Specifying an unknown 2894** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2895** present, then the VFS specified by the option takes precedence over 2896** the value passed as the fourth parameter to sqlite3_open_v2(). 2897** 2898** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2899** "rwc", or "memory". Attempting to set it to any other value is 2900** an error)^. 2901** ^If "ro" is specified, then the database is opened for read-only 2902** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2903** third argument to sqlite3_open_v2(). ^If the mode option is set to 2904** "rw", then the database is opened for read-write (but not create) 2905** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2906** been set. ^Value "rwc" is equivalent to setting both 2907** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2908** set to "memory" then a pure [in-memory database] that never reads 2909** or writes from disk is used. ^It is an error to specify a value for 2910** the mode parameter that is less restrictive than that specified by 2911** the flags passed in the third parameter to sqlite3_open_v2(). 2912** 2913** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2914** "private". ^Setting it to "shared" is equivalent to setting the 2915** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2916** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2917** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2918** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2919** a URI filename, its value overrides any behavior requested by setting 2920** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2921** 2922** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 2923** [powersafe overwrite] property does or does not apply to the 2924** storage media on which the database file resides. 2925** 2926** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 2927** which if set disables file locking in rollback journal modes. This 2928** is useful for accessing a database on a filesystem that does not 2929** support locking. Caution: Database corruption might result if two 2930** or more processes write to the same database and any one of those 2931** processes uses nolock=1. 2932** 2933** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 2934** parameter that indicates that the database file is stored on 2935** read-only media. ^When immutable is set, SQLite assumes that the 2936** database file cannot be changed, even by a process with higher 2937** privilege, and so the database is opened read-only and all locking 2938** and change detection is disabled. Caution: Setting the immutable 2939** property on a database file that does in fact change can result 2940** in incorrect query results and/or [SQLITE_CORRUPT] errors. 2941** See also: [SQLITE_IOCAP_IMMUTABLE]. 2942** 2943** </ul> 2944** 2945** ^Specifying an unknown parameter in the query component of a URI is not an 2946** error. Future versions of SQLite might understand additional query 2947** parameters. See "[query parameters with special meaning to SQLite]" for 2948** additional information. 2949** 2950** [[URI filename examples]] <h3>URI filename examples</h3> 2951** 2952** <table border="1" align=center cellpadding=5> 2953** <tr><th> URI filenames <th> Results 2954** <tr><td> file:data.db <td> 2955** Open the file "data.db" in the current directory. 2956** <tr><td> file:/home/fred/data.db<br> 2957** file:///home/fred/data.db <br> 2958** file://localhost/home/fred/data.db <br> <td> 2959** Open the database file "/home/fred/data.db". 2960** <tr><td> file://darkstar/home/fred/data.db <td> 2961** An error. "darkstar" is not a recognized authority. 2962** <tr><td style="white-space:nowrap"> 2963** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2964** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2965** C:. Note that the %20 escaping in this example is not strictly 2966** necessary - space characters can be used literally 2967** in URI filenames. 2968** <tr><td> file:data.db?mode=ro&cache=private <td> 2969** Open file "data.db" in the current directory for read-only access. 2970** Regardless of whether or not shared-cache mode is enabled by 2971** default, use a private cache. 2972** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 2973** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 2974** that uses dot-files in place of posix advisory locking. 2975** <tr><td> file:data.db?mode=readonly <td> 2976** An error. "readonly" is not a valid option for the "mode" parameter. 2977** </table> 2978** 2979** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2980** query components of a URI. A hexadecimal escape sequence consists of a 2981** percent sign - "%" - followed by exactly two hexadecimal digits 2982** specifying an octet value. ^Before the path or query components of a 2983** URI filename are interpreted, they are encoded using UTF-8 and all 2984** hexadecimal escape sequences replaced by a single byte containing the 2985** corresponding octet. If this process generates an invalid UTF-8 encoding, 2986** the results are undefined. 2987** 2988** <b>Note to Windows users:</b> The encoding used for the filename argument 2989** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2990** codepage is currently defined. Filenames containing international 2991** characters must be converted to UTF-8 prior to passing them into 2992** sqlite3_open() or sqlite3_open_v2(). 2993** 2994** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2995** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2996** features that require the use of temporary files may fail. 2997** 2998** See also: [sqlite3_temp_directory] 2999*/ 3000int sqlite3_open( 3001 const char *filename, /* Database filename (UTF-8) */ 3002 sqlite3 **ppDb /* OUT: SQLite db handle */ 3003); 3004int sqlite3_open16( 3005 const void *filename, /* Database filename (UTF-16) */ 3006 sqlite3 **ppDb /* OUT: SQLite db handle */ 3007); 3008int sqlite3_open_v2( 3009 const char *filename, /* Database filename (UTF-8) */ 3010 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3011 int flags, /* Flags */ 3012 const char *zVfs /* Name of VFS module to use */ 3013); 3014 3015/* 3016** CAPI3REF: Obtain Values For URI Parameters 3017** 3018** These are utility routines, useful to VFS implementations, that check 3019** to see if a database file was a URI that contained a specific query 3020** parameter, and if so obtains the value of that query parameter. 3021** 3022** If F is the database filename pointer passed into the xOpen() method of 3023** a VFS implementation when the flags parameter to xOpen() has one or 3024** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3025** P is the name of the query parameter, then 3026** sqlite3_uri_parameter(F,P) returns the value of the P 3027** parameter if it exists or a NULL pointer if P does not appear as a 3028** query parameter on F. If P is a query parameter of F 3029** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3030** a pointer to an empty string. 3031** 3032** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3033** parameter and returns true (1) or false (0) according to the value 3034** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3035** value of query parameter P is one of "yes", "true", or "on" in any 3036** case or if the value begins with a non-zero number. The 3037** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3038** query parameter P is one of "no", "false", or "off" in any case or 3039** if the value begins with a numeric zero. If P is not a query 3040** parameter on F or if the value of P is does not match any of the 3041** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3042** 3043** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3044** 64-bit signed integer and returns that integer, or D if P does not 3045** exist. If the value of P is something other than an integer, then 3046** zero is returned. 3047** 3048** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3049** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3050** is not a database file pathname pointer that SQLite passed into the xOpen 3051** VFS method, then the behavior of this routine is undefined and probably 3052** undesirable. 3053*/ 3054const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3055int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3056sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3057 3058 3059/* 3060** CAPI3REF: Error Codes And Messages 3061** METHOD: sqlite3 3062** 3063** ^If the most recent sqlite3_* API call associated with 3064** [database connection] D failed, then the sqlite3_errcode(D) interface 3065** returns the numeric [result code] or [extended result code] for that 3066** API call. 3067** If the most recent API call was successful, 3068** then the return value from sqlite3_errcode() is undefined. 3069** ^The sqlite3_extended_errcode() 3070** interface is the same except that it always returns the 3071** [extended result code] even when extended result codes are 3072** disabled. 3073** 3074** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3075** text that describes the error, as either UTF-8 or UTF-16 respectively. 3076** ^(Memory to hold the error message string is managed internally. 3077** The application does not need to worry about freeing the result. 3078** However, the error string might be overwritten or deallocated by 3079** subsequent calls to other SQLite interface functions.)^ 3080** 3081** ^The sqlite3_errstr() interface returns the English-language text 3082** that describes the [result code], as UTF-8. 3083** ^(Memory to hold the error message string is managed internally 3084** and must not be freed by the application)^. 3085** 3086** When the serialized [threading mode] is in use, it might be the 3087** case that a second error occurs on a separate thread in between 3088** the time of the first error and the call to these interfaces. 3089** When that happens, the second error will be reported since these 3090** interfaces always report the most recent result. To avoid 3091** this, each thread can obtain exclusive use of the [database connection] D 3092** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3093** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3094** all calls to the interfaces listed here are completed. 3095** 3096** If an interface fails with SQLITE_MISUSE, that means the interface 3097** was invoked incorrectly by the application. In that case, the 3098** error code and message may or may not be set. 3099*/ 3100int sqlite3_errcode(sqlite3 *db); 3101int sqlite3_extended_errcode(sqlite3 *db); 3102const char *sqlite3_errmsg(sqlite3*); 3103const void *sqlite3_errmsg16(sqlite3*); 3104const char *sqlite3_errstr(int); 3105 3106/* 3107** CAPI3REF: Prepared Statement Object 3108** KEYWORDS: {prepared statement} {prepared statements} 3109** 3110** An instance of this object represents a single SQL statement that 3111** has been compiled into binary form and is ready to be evaluated. 3112** 3113** Think of each SQL statement as a separate computer program. The 3114** original SQL text is source code. A prepared statement object 3115** is the compiled object code. All SQL must be converted into a 3116** prepared statement before it can be run. 3117** 3118** The life-cycle of a prepared statement object usually goes like this: 3119** 3120** <ol> 3121** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3122** <li> Bind values to [parameters] using the sqlite3_bind_*() 3123** interfaces. 3124** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3125** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3126** to step 2. Do this zero or more times. 3127** <li> Destroy the object using [sqlite3_finalize()]. 3128** </ol> 3129*/ 3130typedef struct sqlite3_stmt sqlite3_stmt; 3131 3132/* 3133** CAPI3REF: Run-time Limits 3134** METHOD: sqlite3 3135** 3136** ^(This interface allows the size of various constructs to be limited 3137** on a connection by connection basis. The first parameter is the 3138** [database connection] whose limit is to be set or queried. The 3139** second parameter is one of the [limit categories] that define a 3140** class of constructs to be size limited. The third parameter is the 3141** new limit for that construct.)^ 3142** 3143** ^If the new limit is a negative number, the limit is unchanged. 3144** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3145** [limits | hard upper bound] 3146** set at compile-time by a C preprocessor macro called 3147** [limits | SQLITE_MAX_<i>NAME</i>]. 3148** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3149** ^Attempts to increase a limit above its hard upper bound are 3150** silently truncated to the hard upper bound. 3151** 3152** ^Regardless of whether or not the limit was changed, the 3153** [sqlite3_limit()] interface returns the prior value of the limit. 3154** ^Hence, to find the current value of a limit without changing it, 3155** simply invoke this interface with the third parameter set to -1. 3156** 3157** Run-time limits are intended for use in applications that manage 3158** both their own internal database and also databases that are controlled 3159** by untrusted external sources. An example application might be a 3160** web browser that has its own databases for storing history and 3161** separate databases controlled by JavaScript applications downloaded 3162** off the Internet. The internal databases can be given the 3163** large, default limits. Databases managed by external sources can 3164** be given much smaller limits designed to prevent a denial of service 3165** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3166** interface to further control untrusted SQL. The size of the database 3167** created by an untrusted script can be contained using the 3168** [max_page_count] [PRAGMA]. 3169** 3170** New run-time limit categories may be added in future releases. 3171*/ 3172int sqlite3_limit(sqlite3*, int id, int newVal); 3173 3174/* 3175** CAPI3REF: Run-Time Limit Categories 3176** KEYWORDS: {limit category} {*limit categories} 3177** 3178** These constants define various performance limits 3179** that can be lowered at run-time using [sqlite3_limit()]. 3180** The synopsis of the meanings of the various limits is shown below. 3181** Additional information is available at [limits | Limits in SQLite]. 3182** 3183** <dl> 3184** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3185** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3186** 3187** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3188** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3189** 3190** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3191** <dd>The maximum number of columns in a table definition or in the 3192** result set of a [SELECT] or the maximum number of columns in an index 3193** or in an ORDER BY or GROUP BY clause.</dd>)^ 3194** 3195** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3196** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3197** 3198** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3199** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3200** 3201** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3202** <dd>The maximum number of instructions in a virtual machine program 3203** used to implement an SQL statement. This limit is not currently 3204** enforced, though that might be added in some future release of 3205** SQLite.</dd>)^ 3206** 3207** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3208** <dd>The maximum number of arguments on a function.</dd>)^ 3209** 3210** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3211** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3212** 3213** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3214** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3215** <dd>The maximum length of the pattern argument to the [LIKE] or 3216** [GLOB] operators.</dd>)^ 3217** 3218** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3219** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3220** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3221** 3222** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3223** <dd>The maximum depth of recursion for triggers.</dd>)^ 3224** 3225** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3226** <dd>The maximum number of auxiliary worker threads that a single 3227** [prepared statement] may start.</dd>)^ 3228** </dl> 3229*/ 3230#define SQLITE_LIMIT_LENGTH 0 3231#define SQLITE_LIMIT_SQL_LENGTH 1 3232#define SQLITE_LIMIT_COLUMN 2 3233#define SQLITE_LIMIT_EXPR_DEPTH 3 3234#define SQLITE_LIMIT_COMPOUND_SELECT 4 3235#define SQLITE_LIMIT_VDBE_OP 5 3236#define SQLITE_LIMIT_FUNCTION_ARG 6 3237#define SQLITE_LIMIT_ATTACHED 7 3238#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3239#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3240#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3241#define SQLITE_LIMIT_WORKER_THREADS 11 3242 3243/* 3244** CAPI3REF: Compiling An SQL Statement 3245** KEYWORDS: {SQL statement compiler} 3246** METHOD: sqlite3 3247** CONSTRUCTOR: sqlite3_stmt 3248** 3249** To execute an SQL query, it must first be compiled into a byte-code 3250** program using one of these routines. 3251** 3252** The first argument, "db", is a [database connection] obtained from a 3253** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3254** [sqlite3_open16()]. The database connection must not have been closed. 3255** 3256** The second argument, "zSql", is the statement to be compiled, encoded 3257** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3258** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3259** use UTF-16. 3260** 3261** ^If the nByte argument is negative, then zSql is read up to the 3262** first zero terminator. ^If nByte is positive, then it is the 3263** number of bytes read from zSql. ^If nByte is zero, then no prepared 3264** statement is generated. 3265** If the caller knows that the supplied string is nul-terminated, then 3266** there is a small performance advantage to passing an nByte parameter that 3267** is the number of bytes in the input string <i>including</i> 3268** the nul-terminator. 3269** 3270** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3271** past the end of the first SQL statement in zSql. These routines only 3272** compile the first statement in zSql, so *pzTail is left pointing to 3273** what remains uncompiled. 3274** 3275** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3276** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3277** to NULL. ^If the input text contains no SQL (if the input is an empty 3278** string or a comment) then *ppStmt is set to NULL. 3279** The calling procedure is responsible for deleting the compiled 3280** SQL statement using [sqlite3_finalize()] after it has finished with it. 3281** ppStmt may not be NULL. 3282** 3283** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3284** otherwise an [error code] is returned. 3285** 3286** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3287** recommended for all new programs. The two older interfaces are retained 3288** for backwards compatibility, but their use is discouraged. 3289** ^In the "v2" interfaces, the prepared statement 3290** that is returned (the [sqlite3_stmt] object) contains a copy of the 3291** original SQL text. This causes the [sqlite3_step()] interface to 3292** behave differently in three ways: 3293** 3294** <ol> 3295** <li> 3296** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3297** always used to do, [sqlite3_step()] will automatically recompile the SQL 3298** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3299** retries will occur before sqlite3_step() gives up and returns an error. 3300** </li> 3301** 3302** <li> 3303** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3304** [error codes] or [extended error codes]. ^The legacy behavior was that 3305** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3306** and the application would have to make a second call to [sqlite3_reset()] 3307** in order to find the underlying cause of the problem. With the "v2" prepare 3308** interfaces, the underlying reason for the error is returned immediately. 3309** </li> 3310** 3311** <li> 3312** ^If the specific value bound to [parameter | host parameter] in the 3313** WHERE clause might influence the choice of query plan for a statement, 3314** then the statement will be automatically recompiled, as if there had been 3315** a schema change, on the first [sqlite3_step()] call following any change 3316** to the [sqlite3_bind_text | bindings] of that [parameter]. 3317** ^The specific value of WHERE-clause [parameter] might influence the 3318** choice of query plan if the parameter is the left-hand side of a [LIKE] 3319** or [GLOB] operator or if the parameter is compared to an indexed column 3320** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3321** </li> 3322** </ol> 3323*/ 3324int sqlite3_prepare( 3325 sqlite3 *db, /* Database handle */ 3326 const char *zSql, /* SQL statement, UTF-8 encoded */ 3327 int nByte, /* Maximum length of zSql in bytes. */ 3328 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3329 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3330); 3331int sqlite3_prepare_v2( 3332 sqlite3 *db, /* Database handle */ 3333 const char *zSql, /* SQL statement, UTF-8 encoded */ 3334 int nByte, /* Maximum length of zSql in bytes. */ 3335 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3336 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3337); 3338int sqlite3_prepare16( 3339 sqlite3 *db, /* Database handle */ 3340 const void *zSql, /* SQL statement, UTF-16 encoded */ 3341 int nByte, /* Maximum length of zSql in bytes. */ 3342 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3343 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3344); 3345int sqlite3_prepare16_v2( 3346 sqlite3 *db, /* Database handle */ 3347 const void *zSql, /* SQL statement, UTF-16 encoded */ 3348 int nByte, /* Maximum length of zSql in bytes. */ 3349 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3350 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3351); 3352 3353/* 3354** CAPI3REF: Retrieving Statement SQL 3355** METHOD: sqlite3_stmt 3356** 3357** ^This interface can be used to retrieve a saved copy of the original 3358** SQL text used to create a [prepared statement] if that statement was 3359** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3360*/ 3361const char *sqlite3_sql(sqlite3_stmt *pStmt); 3362 3363/* 3364** CAPI3REF: Determine If An SQL Statement Writes The Database 3365** METHOD: sqlite3_stmt 3366** 3367** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3368** and only if the [prepared statement] X makes no direct changes to 3369** the content of the database file. 3370** 3371** Note that [application-defined SQL functions] or 3372** [virtual tables] might change the database indirectly as a side effect. 3373** ^(For example, if an application defines a function "eval()" that 3374** calls [sqlite3_exec()], then the following SQL statement would 3375** change the database file through side-effects: 3376** 3377** <blockquote><pre> 3378** SELECT eval('DELETE FROM t1') FROM t2; 3379** </pre></blockquote> 3380** 3381** But because the [SELECT] statement does not change the database file 3382** directly, sqlite3_stmt_readonly() would still return true.)^ 3383** 3384** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3385** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3386** since the statements themselves do not actually modify the database but 3387** rather they control the timing of when other statements modify the 3388** database. ^The [ATTACH] and [DETACH] statements also cause 3389** sqlite3_stmt_readonly() to return true since, while those statements 3390** change the configuration of a database connection, they do not make 3391** changes to the content of the database files on disk. 3392*/ 3393int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3394 3395/* 3396** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3397** METHOD: sqlite3_stmt 3398** 3399** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3400** [prepared statement] S has been stepped at least once using 3401** [sqlite3_step(S)] but has neither run to completion (returned 3402** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3403** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3404** interface returns false if S is a NULL pointer. If S is not a 3405** NULL pointer and is not a pointer to a valid [prepared statement] 3406** object, then the behavior is undefined and probably undesirable. 3407** 3408** This interface can be used in combination [sqlite3_next_stmt()] 3409** to locate all prepared statements associated with a database 3410** connection that are in need of being reset. This can be used, 3411** for example, in diagnostic routines to search for prepared 3412** statements that are holding a transaction open. 3413*/ 3414int sqlite3_stmt_busy(sqlite3_stmt*); 3415 3416/* 3417** CAPI3REF: Dynamically Typed Value Object 3418** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3419** 3420** SQLite uses the sqlite3_value object to represent all values 3421** that can be stored in a database table. SQLite uses dynamic typing 3422** for the values it stores. ^Values stored in sqlite3_value objects 3423** can be integers, floating point values, strings, BLOBs, or NULL. 3424** 3425** An sqlite3_value object may be either "protected" or "unprotected". 3426** Some interfaces require a protected sqlite3_value. Other interfaces 3427** will accept either a protected or an unprotected sqlite3_value. 3428** Every interface that accepts sqlite3_value arguments specifies 3429** whether or not it requires a protected sqlite3_value. The 3430** [sqlite3_value_dup()] interface can be used to construct a new 3431** protected sqlite3_value from an unprotected sqlite3_value. 3432** 3433** The terms "protected" and "unprotected" refer to whether or not 3434** a mutex is held. An internal mutex is held for a protected 3435** sqlite3_value object but no mutex is held for an unprotected 3436** sqlite3_value object. If SQLite is compiled to be single-threaded 3437** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3438** or if SQLite is run in one of reduced mutex modes 3439** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3440** then there is no distinction between protected and unprotected 3441** sqlite3_value objects and they can be used interchangeably. However, 3442** for maximum code portability it is recommended that applications 3443** still make the distinction between protected and unprotected 3444** sqlite3_value objects even when not strictly required. 3445** 3446** ^The sqlite3_value objects that are passed as parameters into the 3447** implementation of [application-defined SQL functions] are protected. 3448** ^The sqlite3_value object returned by 3449** [sqlite3_column_value()] is unprotected. 3450** Unprotected sqlite3_value objects may only be used with 3451** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3452** The [sqlite3_value_blob | sqlite3_value_type()] family of 3453** interfaces require protected sqlite3_value objects. 3454*/ 3455typedef struct Mem sqlite3_value; 3456 3457/* 3458** CAPI3REF: SQL Function Context Object 3459** 3460** The context in which an SQL function executes is stored in an 3461** sqlite3_context object. ^A pointer to an sqlite3_context object 3462** is always first parameter to [application-defined SQL functions]. 3463** The application-defined SQL function implementation will pass this 3464** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3465** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3466** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3467** and/or [sqlite3_set_auxdata()]. 3468*/ 3469typedef struct sqlite3_context sqlite3_context; 3470 3471/* 3472** CAPI3REF: Binding Values To Prepared Statements 3473** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3474** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3475** METHOD: sqlite3_stmt 3476** 3477** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3478** literals may be replaced by a [parameter] that matches one of following 3479** templates: 3480** 3481** <ul> 3482** <li> ? 3483** <li> ?NNN 3484** <li> :VVV 3485** <li> @VVV 3486** <li> $VVV 3487** </ul> 3488** 3489** In the templates above, NNN represents an integer literal, 3490** and VVV represents an alphanumeric identifier.)^ ^The values of these 3491** parameters (also called "host parameter names" or "SQL parameters") 3492** can be set using the sqlite3_bind_*() routines defined here. 3493** 3494** ^The first argument to the sqlite3_bind_*() routines is always 3495** a pointer to the [sqlite3_stmt] object returned from 3496** [sqlite3_prepare_v2()] or its variants. 3497** 3498** ^The second argument is the index of the SQL parameter to be set. 3499** ^The leftmost SQL parameter has an index of 1. ^When the same named 3500** SQL parameter is used more than once, second and subsequent 3501** occurrences have the same index as the first occurrence. 3502** ^The index for named parameters can be looked up using the 3503** [sqlite3_bind_parameter_index()] API if desired. ^The index 3504** for "?NNN" parameters is the value of NNN. 3505** ^The NNN value must be between 1 and the [sqlite3_limit()] 3506** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3507** 3508** ^The third argument is the value to bind to the parameter. 3509** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3510** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3511** is ignored and the end result is the same as sqlite3_bind_null(). 3512** 3513** ^(In those routines that have a fourth argument, its value is the 3514** number of bytes in the parameter. To be clear: the value is the 3515** number of <u>bytes</u> in the value, not the number of characters.)^ 3516** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3517** is negative, then the length of the string is 3518** the number of bytes up to the first zero terminator. 3519** If the fourth parameter to sqlite3_bind_blob() is negative, then 3520** the behavior is undefined. 3521** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3522** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3523** that parameter must be the byte offset 3524** where the NUL terminator would occur assuming the string were NUL 3525** terminated. If any NUL characters occur at byte offsets less than 3526** the value of the fourth parameter then the resulting string value will 3527** contain embedded NULs. The result of expressions involving strings 3528** with embedded NULs is undefined. 3529** 3530** ^The fifth argument to the BLOB and string binding interfaces 3531** is a destructor used to dispose of the BLOB or 3532** string after SQLite has finished with it. ^The destructor is called 3533** to dispose of the BLOB or string even if the call to bind API fails. 3534** ^If the fifth argument is 3535** the special value [SQLITE_STATIC], then SQLite assumes that the 3536** information is in static, unmanaged space and does not need to be freed. 3537** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3538** SQLite makes its own private copy of the data immediately, before 3539** the sqlite3_bind_*() routine returns. 3540** 3541** ^The sixth argument to sqlite3_bind_text64() must be one of 3542** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3543** to specify the encoding of the text in the third parameter. If 3544** the sixth argument to sqlite3_bind_text64() is not one of the 3545** allowed values shown above, or if the text encoding is different 3546** from the encoding specified by the sixth parameter, then the behavior 3547** is undefined. 3548** 3549** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3550** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3551** (just an integer to hold its size) while it is being processed. 3552** Zeroblobs are intended to serve as placeholders for BLOBs whose 3553** content is later written using 3554** [sqlite3_blob_open | incremental BLOB I/O] routines. 3555** ^A negative value for the zeroblob results in a zero-length BLOB. 3556** 3557** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3558** for the [prepared statement] or with a prepared statement for which 3559** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3560** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3561** routine is passed a [prepared statement] that has been finalized, the 3562** result is undefined and probably harmful. 3563** 3564** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3565** ^Unbound parameters are interpreted as NULL. 3566** 3567** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3568** [error code] if anything goes wrong. 3569** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3570** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3571** [SQLITE_MAX_LENGTH]. 3572** ^[SQLITE_RANGE] is returned if the parameter 3573** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3574** 3575** See also: [sqlite3_bind_parameter_count()], 3576** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3577*/ 3578int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3579int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3580 void(*)(void*)); 3581int sqlite3_bind_double(sqlite3_stmt*, int, double); 3582int sqlite3_bind_int(sqlite3_stmt*, int, int); 3583int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3584int sqlite3_bind_null(sqlite3_stmt*, int); 3585int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3586int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3587int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3588 void(*)(void*), unsigned char encoding); 3589int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3590int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3591int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3592 3593/* 3594** CAPI3REF: Number Of SQL Parameters 3595** METHOD: sqlite3_stmt 3596** 3597** ^This routine can be used to find the number of [SQL parameters] 3598** in a [prepared statement]. SQL parameters are tokens of the 3599** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3600** placeholders for values that are [sqlite3_bind_blob | bound] 3601** to the parameters at a later time. 3602** 3603** ^(This routine actually returns the index of the largest (rightmost) 3604** parameter. For all forms except ?NNN, this will correspond to the 3605** number of unique parameters. If parameters of the ?NNN form are used, 3606** there may be gaps in the list.)^ 3607** 3608** See also: [sqlite3_bind_blob|sqlite3_bind()], 3609** [sqlite3_bind_parameter_name()], and 3610** [sqlite3_bind_parameter_index()]. 3611*/ 3612int sqlite3_bind_parameter_count(sqlite3_stmt*); 3613 3614/* 3615** CAPI3REF: Name Of A Host Parameter 3616** METHOD: sqlite3_stmt 3617** 3618** ^The sqlite3_bind_parameter_name(P,N) interface returns 3619** the name of the N-th [SQL parameter] in the [prepared statement] P. 3620** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3621** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3622** respectively. 3623** In other words, the initial ":" or "$" or "@" or "?" 3624** is included as part of the name.)^ 3625** ^Parameters of the form "?" without a following integer have no name 3626** and are referred to as "nameless" or "anonymous parameters". 3627** 3628** ^The first host parameter has an index of 1, not 0. 3629** 3630** ^If the value N is out of range or if the N-th parameter is 3631** nameless, then NULL is returned. ^The returned string is 3632** always in UTF-8 encoding even if the named parameter was 3633** originally specified as UTF-16 in [sqlite3_prepare16()] or 3634** [sqlite3_prepare16_v2()]. 3635** 3636** See also: [sqlite3_bind_blob|sqlite3_bind()], 3637** [sqlite3_bind_parameter_count()], and 3638** [sqlite3_bind_parameter_index()]. 3639*/ 3640const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3641 3642/* 3643** CAPI3REF: Index Of A Parameter With A Given Name 3644** METHOD: sqlite3_stmt 3645** 3646** ^Return the index of an SQL parameter given its name. ^The 3647** index value returned is suitable for use as the second 3648** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3649** is returned if no matching parameter is found. ^The parameter 3650** name must be given in UTF-8 even if the original statement 3651** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3652** 3653** See also: [sqlite3_bind_blob|sqlite3_bind()], 3654** [sqlite3_bind_parameter_count()], and 3655** [sqlite3_bind_parameter_name()]. 3656*/ 3657int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3658 3659/* 3660** CAPI3REF: Reset All Bindings On A Prepared Statement 3661** METHOD: sqlite3_stmt 3662** 3663** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3664** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3665** ^Use this routine to reset all host parameters to NULL. 3666*/ 3667int sqlite3_clear_bindings(sqlite3_stmt*); 3668 3669/* 3670** CAPI3REF: Number Of Columns In A Result Set 3671** METHOD: sqlite3_stmt 3672** 3673** ^Return the number of columns in the result set returned by the 3674** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3675** statement that does not return data (for example an [UPDATE]). 3676** 3677** See also: [sqlite3_data_count()] 3678*/ 3679int sqlite3_column_count(sqlite3_stmt *pStmt); 3680 3681/* 3682** CAPI3REF: Column Names In A Result Set 3683** METHOD: sqlite3_stmt 3684** 3685** ^These routines return the name assigned to a particular column 3686** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3687** interface returns a pointer to a zero-terminated UTF-8 string 3688** and sqlite3_column_name16() returns a pointer to a zero-terminated 3689** UTF-16 string. ^The first parameter is the [prepared statement] 3690** that implements the [SELECT] statement. ^The second parameter is the 3691** column number. ^The leftmost column is number 0. 3692** 3693** ^The returned string pointer is valid until either the [prepared statement] 3694** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3695** reprepared by the first call to [sqlite3_step()] for a particular run 3696** or until the next call to 3697** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3698** 3699** ^If sqlite3_malloc() fails during the processing of either routine 3700** (for example during a conversion from UTF-8 to UTF-16) then a 3701** NULL pointer is returned. 3702** 3703** ^The name of a result column is the value of the "AS" clause for 3704** that column, if there is an AS clause. If there is no AS clause 3705** then the name of the column is unspecified and may change from 3706** one release of SQLite to the next. 3707*/ 3708const char *sqlite3_column_name(sqlite3_stmt*, int N); 3709const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3710 3711/* 3712** CAPI3REF: Source Of Data In A Query Result 3713** METHOD: sqlite3_stmt 3714** 3715** ^These routines provide a means to determine the database, table, and 3716** table column that is the origin of a particular result column in 3717** [SELECT] statement. 3718** ^The name of the database or table or column can be returned as 3719** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3720** the database name, the _table_ routines return the table name, and 3721** the origin_ routines return the column name. 3722** ^The returned string is valid until the [prepared statement] is destroyed 3723** using [sqlite3_finalize()] or until the statement is automatically 3724** reprepared by the first call to [sqlite3_step()] for a particular run 3725** or until the same information is requested 3726** again in a different encoding. 3727** 3728** ^The names returned are the original un-aliased names of the 3729** database, table, and column. 3730** 3731** ^The first argument to these interfaces is a [prepared statement]. 3732** ^These functions return information about the Nth result column returned by 3733** the statement, where N is the second function argument. 3734** ^The left-most column is column 0 for these routines. 3735** 3736** ^If the Nth column returned by the statement is an expression or 3737** subquery and is not a column value, then all of these functions return 3738** NULL. ^These routine might also return NULL if a memory allocation error 3739** occurs. ^Otherwise, they return the name of the attached database, table, 3740** or column that query result column was extracted from. 3741** 3742** ^As with all other SQLite APIs, those whose names end with "16" return 3743** UTF-16 encoded strings and the other functions return UTF-8. 3744** 3745** ^These APIs are only available if the library was compiled with the 3746** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3747** 3748** If two or more threads call one or more of these routines against the same 3749** prepared statement and column at the same time then the results are 3750** undefined. 3751** 3752** If two or more threads call one or more 3753** [sqlite3_column_database_name | column metadata interfaces] 3754** for the same [prepared statement] and result column 3755** at the same time then the results are undefined. 3756*/ 3757const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3758const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3759const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3760const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3761const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3762const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3763 3764/* 3765** CAPI3REF: Declared Datatype Of A Query Result 3766** METHOD: sqlite3_stmt 3767** 3768** ^(The first parameter is a [prepared statement]. 3769** If this statement is a [SELECT] statement and the Nth column of the 3770** returned result set of that [SELECT] is a table column (not an 3771** expression or subquery) then the declared type of the table 3772** column is returned.)^ ^If the Nth column of the result set is an 3773** expression or subquery, then a NULL pointer is returned. 3774** ^The returned string is always UTF-8 encoded. 3775** 3776** ^(For example, given the database schema: 3777** 3778** CREATE TABLE t1(c1 VARIANT); 3779** 3780** and the following statement to be compiled: 3781** 3782** SELECT c1 + 1, c1 FROM t1; 3783** 3784** this routine would return the string "VARIANT" for the second result 3785** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3786** 3787** ^SQLite uses dynamic run-time typing. ^So just because a column 3788** is declared to contain a particular type does not mean that the 3789** data stored in that column is of the declared type. SQLite is 3790** strongly typed, but the typing is dynamic not static. ^Type 3791** is associated with individual values, not with the containers 3792** used to hold those values. 3793*/ 3794const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3795const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3796 3797/* 3798** CAPI3REF: Evaluate An SQL Statement 3799** METHOD: sqlite3_stmt 3800** 3801** After a [prepared statement] has been prepared using either 3802** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3803** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3804** must be called one or more times to evaluate the statement. 3805** 3806** The details of the behavior of the sqlite3_step() interface depend 3807** on whether the statement was prepared using the newer "v2" interface 3808** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3809** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3810** new "v2" interface is recommended for new applications but the legacy 3811** interface will continue to be supported. 3812** 3813** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3814** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3815** ^With the "v2" interface, any of the other [result codes] or 3816** [extended result codes] might be returned as well. 3817** 3818** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3819** database locks it needs to do its job. ^If the statement is a [COMMIT] 3820** or occurs outside of an explicit transaction, then you can retry the 3821** statement. If the statement is not a [COMMIT] and occurs within an 3822** explicit transaction then you should rollback the transaction before 3823** continuing. 3824** 3825** ^[SQLITE_DONE] means that the statement has finished executing 3826** successfully. sqlite3_step() should not be called again on this virtual 3827** machine without first calling [sqlite3_reset()] to reset the virtual 3828** machine back to its initial state. 3829** 3830** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3831** is returned each time a new row of data is ready for processing by the 3832** caller. The values may be accessed using the [column access functions]. 3833** sqlite3_step() is called again to retrieve the next row of data. 3834** 3835** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3836** violation) has occurred. sqlite3_step() should not be called again on 3837** the VM. More information may be found by calling [sqlite3_errmsg()]. 3838** ^With the legacy interface, a more specific error code (for example, 3839** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3840** can be obtained by calling [sqlite3_reset()] on the 3841** [prepared statement]. ^In the "v2" interface, 3842** the more specific error code is returned directly by sqlite3_step(). 3843** 3844** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3845** Perhaps it was called on a [prepared statement] that has 3846** already been [sqlite3_finalize | finalized] or on one that had 3847** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3848** be the case that the same database connection is being used by two or 3849** more threads at the same moment in time. 3850** 3851** For all versions of SQLite up to and including 3.6.23.1, a call to 3852** [sqlite3_reset()] was required after sqlite3_step() returned anything 3853** other than [SQLITE_ROW] before any subsequent invocation of 3854** sqlite3_step(). Failure to reset the prepared statement using 3855** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3856** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3857** calling [sqlite3_reset()] automatically in this circumstance rather 3858** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3859** break because any application that ever receives an SQLITE_MISUSE error 3860** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3861** can be used to restore the legacy behavior. 3862** 3863** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3864** API always returns a generic error code, [SQLITE_ERROR], following any 3865** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3866** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3867** specific [error codes] that better describes the error. 3868** We admit that this is a goofy design. The problem has been fixed 3869** with the "v2" interface. If you prepare all of your SQL statements 3870** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3871** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3872** then the more specific [error codes] are returned directly 3873** by sqlite3_step(). The use of the "v2" interface is recommended. 3874*/ 3875int sqlite3_step(sqlite3_stmt*); 3876 3877/* 3878** CAPI3REF: Number of columns in a result set 3879** METHOD: sqlite3_stmt 3880** 3881** ^The sqlite3_data_count(P) interface returns the number of columns in the 3882** current row of the result set of [prepared statement] P. 3883** ^If prepared statement P does not have results ready to return 3884** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3885** interfaces) then sqlite3_data_count(P) returns 0. 3886** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3887** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3888** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3889** will return non-zero if previous call to [sqlite3_step](P) returned 3890** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3891** where it always returns zero since each step of that multi-step 3892** pragma returns 0 columns of data. 3893** 3894** See also: [sqlite3_column_count()] 3895*/ 3896int sqlite3_data_count(sqlite3_stmt *pStmt); 3897 3898/* 3899** CAPI3REF: Fundamental Datatypes 3900** KEYWORDS: SQLITE_TEXT 3901** 3902** ^(Every value in SQLite has one of five fundamental datatypes: 3903** 3904** <ul> 3905** <li> 64-bit signed integer 3906** <li> 64-bit IEEE floating point number 3907** <li> string 3908** <li> BLOB 3909** <li> NULL 3910** </ul>)^ 3911** 3912** These constants are codes for each of those types. 3913** 3914** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3915** for a completely different meaning. Software that links against both 3916** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3917** SQLITE_TEXT. 3918*/ 3919#define SQLITE_INTEGER 1 3920#define SQLITE_FLOAT 2 3921#define SQLITE_BLOB 4 3922#define SQLITE_NULL 5 3923#ifdef SQLITE_TEXT 3924# undef SQLITE_TEXT 3925#else 3926# define SQLITE_TEXT 3 3927#endif 3928#define SQLITE3_TEXT 3 3929 3930/* 3931** CAPI3REF: Result Values From A Query 3932** KEYWORDS: {column access functions} 3933** METHOD: sqlite3_stmt 3934** 3935** ^These routines return information about a single column of the current 3936** result row of a query. ^In every case the first argument is a pointer 3937** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3938** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3939** and the second argument is the index of the column for which information 3940** should be returned. ^The leftmost column of the result set has the index 0. 3941** ^The number of columns in the result can be determined using 3942** [sqlite3_column_count()]. 3943** 3944** If the SQL statement does not currently point to a valid row, or if the 3945** column index is out of range, the result is undefined. 3946** These routines may only be called when the most recent call to 3947** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3948** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3949** If any of these routines are called after [sqlite3_reset()] or 3950** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3951** something other than [SQLITE_ROW], the results are undefined. 3952** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3953** are called from a different thread while any of these routines 3954** are pending, then the results are undefined. 3955** 3956** ^The sqlite3_column_type() routine returns the 3957** [SQLITE_INTEGER | datatype code] for the initial data type 3958** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3959** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3960** returned by sqlite3_column_type() is only meaningful if no type 3961** conversions have occurred as described below. After a type conversion, 3962** the value returned by sqlite3_column_type() is undefined. Future 3963** versions of SQLite may change the behavior of sqlite3_column_type() 3964** following a type conversion. 3965** 3966** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3967** routine returns the number of bytes in that BLOB or string. 3968** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3969** the string to UTF-8 and then returns the number of bytes. 3970** ^If the result is a numeric value then sqlite3_column_bytes() uses 3971** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3972** the number of bytes in that string. 3973** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3974** 3975** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3976** routine returns the number of bytes in that BLOB or string. 3977** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3978** the string to UTF-16 and then returns the number of bytes. 3979** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3980** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3981** the number of bytes in that string. 3982** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3983** 3984** ^The values returned by [sqlite3_column_bytes()] and 3985** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3986** of the string. ^For clarity: the values returned by 3987** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3988** bytes in the string, not the number of characters. 3989** 3990** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3991** even empty strings, are always zero-terminated. ^The return 3992** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3993** 3994** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 3995** [unprotected sqlite3_value] object. In a multithreaded environment, 3996** an unprotected sqlite3_value object may only be used safely with 3997** [sqlite3_bind_value()] and [sqlite3_result_value()]. 3998** If the [unprotected sqlite3_value] object returned by 3999** [sqlite3_column_value()] is used in any other way, including calls 4000** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4001** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4002** 4003** These routines attempt to convert the value where appropriate. ^For 4004** example, if the internal representation is FLOAT and a text result 4005** is requested, [sqlite3_snprintf()] is used internally to perform the 4006** conversion automatically. ^(The following table details the conversions 4007** that are applied: 4008** 4009** <blockquote> 4010** <table border="1"> 4011** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4012** 4013** <tr><td> NULL <td> INTEGER <td> Result is 0 4014** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4015** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4016** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4017** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4018** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4019** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4020** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4021** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4022** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4023** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4024** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4025** <tr><td> TEXT <td> BLOB <td> No change 4026** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4027** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4028** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4029** </table> 4030** </blockquote>)^ 4031** 4032** Note that when type conversions occur, pointers returned by prior 4033** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4034** sqlite3_column_text16() may be invalidated. 4035** Type conversions and pointer invalidations might occur 4036** in the following cases: 4037** 4038** <ul> 4039** <li> The initial content is a BLOB and sqlite3_column_text() or 4040** sqlite3_column_text16() is called. A zero-terminator might 4041** need to be added to the string.</li> 4042** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4043** sqlite3_column_text16() is called. The content must be converted 4044** to UTF-16.</li> 4045** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4046** sqlite3_column_text() is called. The content must be converted 4047** to UTF-8.</li> 4048** </ul> 4049** 4050** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4051** not invalidate a prior pointer, though of course the content of the buffer 4052** that the prior pointer references will have been modified. Other kinds 4053** of conversion are done in place when it is possible, but sometimes they 4054** are not possible and in those cases prior pointers are invalidated. 4055** 4056** The safest policy is to invoke these routines 4057** in one of the following ways: 4058** 4059** <ul> 4060** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4061** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4062** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4063** </ul> 4064** 4065** In other words, you should call sqlite3_column_text(), 4066** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4067** into the desired format, then invoke sqlite3_column_bytes() or 4068** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4069** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4070** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4071** with calls to sqlite3_column_bytes(). 4072** 4073** ^The pointers returned are valid until a type conversion occurs as 4074** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4075** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4076** and BLOBs is freed automatically. Do <em>not</em> pass the pointers returned 4077** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4078** [sqlite3_free()]. 4079** 4080** ^(If a memory allocation error occurs during the evaluation of any 4081** of these routines, a default value is returned. The default value 4082** is either the integer 0, the floating point number 0.0, or a NULL 4083** pointer. Subsequent calls to [sqlite3_errcode()] will return 4084** [SQLITE_NOMEM].)^ 4085*/ 4086const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4087int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4088int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4089double sqlite3_column_double(sqlite3_stmt*, int iCol); 4090int sqlite3_column_int(sqlite3_stmt*, int iCol); 4091sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4092const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4093const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4094int sqlite3_column_type(sqlite3_stmt*, int iCol); 4095sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4096 4097/* 4098** CAPI3REF: Destroy A Prepared Statement Object 4099** DESTRUCTOR: sqlite3_stmt 4100** 4101** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4102** ^If the most recent evaluation of the statement encountered no errors 4103** or if the statement is never been evaluated, then sqlite3_finalize() returns 4104** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4105** sqlite3_finalize(S) returns the appropriate [error code] or 4106** [extended error code]. 4107** 4108** ^The sqlite3_finalize(S) routine can be called at any point during 4109** the life cycle of [prepared statement] S: 4110** before statement S is ever evaluated, after 4111** one or more calls to [sqlite3_reset()], or after any call 4112** to [sqlite3_step()] regardless of whether or not the statement has 4113** completed execution. 4114** 4115** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4116** 4117** The application must finalize every [prepared statement] in order to avoid 4118** resource leaks. It is a grievous error for the application to try to use 4119** a prepared statement after it has been finalized. Any use of a prepared 4120** statement after it has been finalized can result in undefined and 4121** undesirable behavior such as segfaults and heap corruption. 4122*/ 4123int sqlite3_finalize(sqlite3_stmt *pStmt); 4124 4125/* 4126** CAPI3REF: Reset A Prepared Statement Object 4127** METHOD: sqlite3_stmt 4128** 4129** The sqlite3_reset() function is called to reset a [prepared statement] 4130** object back to its initial state, ready to be re-executed. 4131** ^Any SQL statement variables that had values bound to them using 4132** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4133** Use [sqlite3_clear_bindings()] to reset the bindings. 4134** 4135** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4136** back to the beginning of its program. 4137** 4138** ^If the most recent call to [sqlite3_step(S)] for the 4139** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4140** or if [sqlite3_step(S)] has never before been called on S, 4141** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4142** 4143** ^If the most recent call to [sqlite3_step(S)] for the 4144** [prepared statement] S indicated an error, then 4145** [sqlite3_reset(S)] returns an appropriate [error code]. 4146** 4147** ^The [sqlite3_reset(S)] interface does not change the values 4148** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4149*/ 4150int sqlite3_reset(sqlite3_stmt *pStmt); 4151 4152/* 4153** CAPI3REF: Create Or Redefine SQL Functions 4154** KEYWORDS: {function creation routines} 4155** KEYWORDS: {application-defined SQL function} 4156** KEYWORDS: {application-defined SQL functions} 4157** METHOD: sqlite3 4158** 4159** ^These functions (collectively known as "function creation routines") 4160** are used to add SQL functions or aggregates or to redefine the behavior 4161** of existing SQL functions or aggregates. The only differences between 4162** these routines are the text encoding expected for 4163** the second parameter (the name of the function being created) 4164** and the presence or absence of a destructor callback for 4165** the application data pointer. 4166** 4167** ^The first parameter is the [database connection] to which the SQL 4168** function is to be added. ^If an application uses more than one database 4169** connection then application-defined SQL functions must be added 4170** to each database connection separately. 4171** 4172** ^The second parameter is the name of the SQL function to be created or 4173** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4174** representation, exclusive of the zero-terminator. ^Note that the name 4175** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4176** ^Any attempt to create a function with a longer name 4177** will result in [SQLITE_MISUSE] being returned. 4178** 4179** ^The third parameter (nArg) 4180** is the number of arguments that the SQL function or 4181** aggregate takes. ^If this parameter is -1, then the SQL function or 4182** aggregate may take any number of arguments between 0 and the limit 4183** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4184** parameter is less than -1 or greater than 127 then the behavior is 4185** undefined. 4186** 4187** ^The fourth parameter, eTextRep, specifies what 4188** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4189** its parameters. The application should set this parameter to 4190** [SQLITE_UTF16LE] if the function implementation invokes 4191** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4192** implementation invokes [sqlite3_value_text16be()] on an input, or 4193** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4194** otherwise. ^The same SQL function may be registered multiple times using 4195** different preferred text encodings, with different implementations for 4196** each encoding. 4197** ^When multiple implementations of the same function are available, SQLite 4198** will pick the one that involves the least amount of data conversion. 4199** 4200** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4201** to signal that the function will always return the same result given 4202** the same inputs within a single SQL statement. Most SQL functions are 4203** deterministic. The built-in [random()] SQL function is an example of a 4204** function that is not deterministic. The SQLite query planner is able to 4205** perform additional optimizations on deterministic functions, so use 4206** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4207** 4208** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4209** function can gain access to this pointer using [sqlite3_user_data()].)^ 4210** 4211** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4212** pointers to C-language functions that implement the SQL function or 4213** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4214** callback only; NULL pointers must be passed as the xStep and xFinal 4215** parameters. ^An aggregate SQL function requires an implementation of xStep 4216** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4217** SQL function or aggregate, pass NULL pointers for all three function 4218** callbacks. 4219** 4220** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4221** then it is destructor for the application data pointer. 4222** The destructor is invoked when the function is deleted, either by being 4223** overloaded or when the database connection closes.)^ 4224** ^The destructor is also invoked if the call to 4225** sqlite3_create_function_v2() fails. 4226** ^When the destructor callback of the tenth parameter is invoked, it 4227** is passed a single argument which is a copy of the application data 4228** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4229** 4230** ^It is permitted to register multiple implementations of the same 4231** functions with the same name but with either differing numbers of 4232** arguments or differing preferred text encodings. ^SQLite will use 4233** the implementation that most closely matches the way in which the 4234** SQL function is used. ^A function implementation with a non-negative 4235** nArg parameter is a better match than a function implementation with 4236** a negative nArg. ^A function where the preferred text encoding 4237** matches the database encoding is a better 4238** match than a function where the encoding is different. 4239** ^A function where the encoding difference is between UTF16le and UTF16be 4240** is a closer match than a function where the encoding difference is 4241** between UTF8 and UTF16. 4242** 4243** ^Built-in functions may be overloaded by new application-defined functions. 4244** 4245** ^An application-defined function is permitted to call other 4246** SQLite interfaces. However, such calls must not 4247** close the database connection nor finalize or reset the prepared 4248** statement in which the function is running. 4249*/ 4250int sqlite3_create_function( 4251 sqlite3 *db, 4252 const char *zFunctionName, 4253 int nArg, 4254 int eTextRep, 4255 void *pApp, 4256 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4257 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4258 void (*xFinal)(sqlite3_context*) 4259); 4260int sqlite3_create_function16( 4261 sqlite3 *db, 4262 const void *zFunctionName, 4263 int nArg, 4264 int eTextRep, 4265 void *pApp, 4266 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4267 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4268 void (*xFinal)(sqlite3_context*) 4269); 4270int sqlite3_create_function_v2( 4271 sqlite3 *db, 4272 const char *zFunctionName, 4273 int nArg, 4274 int eTextRep, 4275 void *pApp, 4276 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4277 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4278 void (*xFinal)(sqlite3_context*), 4279 void(*xDestroy)(void*) 4280); 4281 4282/* 4283** CAPI3REF: Text Encodings 4284** 4285** These constant define integer codes that represent the various 4286** text encodings supported by SQLite. 4287*/ 4288#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4289#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4290#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4291#define SQLITE_UTF16 4 /* Use native byte order */ 4292#define SQLITE_ANY 5 /* Deprecated */ 4293#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4294 4295/* 4296** CAPI3REF: Function Flags 4297** 4298** These constants may be ORed together with the 4299** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4300** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4301** [sqlite3_create_function_v2()]. 4302*/ 4303#define SQLITE_DETERMINISTIC 0x800 4304 4305/* 4306** CAPI3REF: Deprecated Functions 4307** DEPRECATED 4308** 4309** These functions are [deprecated]. In order to maintain 4310** backwards compatibility with older code, these functions continue 4311** to be supported. However, new applications should avoid 4312** the use of these functions. To encourage programmers to avoid 4313** these functions, we will not explain what they do. 4314*/ 4315#ifndef SQLITE_OMIT_DEPRECATED 4316SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4317SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4318SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4319SQLITE_DEPRECATED int sqlite3_global_recover(void); 4320SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4321SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4322 void*,sqlite3_int64); 4323#endif 4324 4325/* 4326** CAPI3REF: Obtaining SQL Values 4327** METHOD: sqlite3_value 4328** 4329** The C-language implementation of SQL functions and aggregates uses 4330** this set of interface routines to access the parameter values on 4331** the function or aggregate. 4332** 4333** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4334** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4335** define callbacks that implement the SQL functions and aggregates. 4336** The 3rd parameter to these callbacks is an array of pointers to 4337** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4338** each parameter to the SQL function. These routines are used to 4339** extract values from the [sqlite3_value] objects. 4340** 4341** These routines work only with [protected sqlite3_value] objects. 4342** Any attempt to use these routines on an [unprotected sqlite3_value] 4343** object results in undefined behavior. 4344** 4345** ^These routines work just like the corresponding [column access functions] 4346** except that these routines take a single [protected sqlite3_value] object 4347** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4348** 4349** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4350** in the native byte-order of the host machine. ^The 4351** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4352** extract UTF-16 strings as big-endian and little-endian respectively. 4353** 4354** ^(The sqlite3_value_numeric_type() interface attempts to apply 4355** numeric affinity to the value. This means that an attempt is 4356** made to convert the value to an integer or floating point. If 4357** such a conversion is possible without loss of information (in other 4358** words, if the value is a string that looks like a number) 4359** then the conversion is performed. Otherwise no conversion occurs. 4360** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4361** 4362** Please pay particular attention to the fact that the pointer returned 4363** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4364** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4365** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4366** or [sqlite3_value_text16()]. 4367** 4368** These routines must be called from the same thread as 4369** the SQL function that supplied the [sqlite3_value*] parameters. 4370*/ 4371const void *sqlite3_value_blob(sqlite3_value*); 4372int sqlite3_value_bytes(sqlite3_value*); 4373int sqlite3_value_bytes16(sqlite3_value*); 4374double sqlite3_value_double(sqlite3_value*); 4375int sqlite3_value_int(sqlite3_value*); 4376sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4377const unsigned char *sqlite3_value_text(sqlite3_value*); 4378const void *sqlite3_value_text16(sqlite3_value*); 4379const void *sqlite3_value_text16le(sqlite3_value*); 4380const void *sqlite3_value_text16be(sqlite3_value*); 4381int sqlite3_value_type(sqlite3_value*); 4382int sqlite3_value_numeric_type(sqlite3_value*); 4383 4384/* 4385** CAPI3REF: Finding The Subtype Of SQL Values 4386** METHOD: sqlite3_value 4387** 4388** The sqlite3_value_subtype(V) function returns the subtype for 4389** an [application-defined SQL function] argument V. The subtype 4390** information can be used to pass a limited amount of context from 4391** one SQL function to another. Use the [sqlite3_result_subtype()] 4392** routine to set the subtype for the return value of an SQL function. 4393** 4394** SQLite makes no use of subtype itself. It merely passes the subtype 4395** from the result of one [application-defined SQL function] into the 4396** input of another. 4397*/ 4398unsigned int sqlite3_value_subtype(sqlite3_value*); 4399 4400/* 4401** CAPI3REF: Copy And Free SQL Values 4402** METHOD: sqlite3_value 4403** 4404** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4405** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4406** is a [protected sqlite3_value] object even if the input is not. 4407** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4408** memory allocation fails. 4409** 4410** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4411** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4412** then sqlite3_value_free(V) is a harmless no-op. 4413*/ 4414sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4415void sqlite3_value_free(sqlite3_value*); 4416 4417/* 4418** CAPI3REF: Obtain Aggregate Function Context 4419** METHOD: sqlite3_context 4420** 4421** Implementations of aggregate SQL functions use this 4422** routine to allocate memory for storing their state. 4423** 4424** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4425** for a particular aggregate function, SQLite 4426** allocates N of memory, zeroes out that memory, and returns a pointer 4427** to the new memory. ^On second and subsequent calls to 4428** sqlite3_aggregate_context() for the same aggregate function instance, 4429** the same buffer is returned. Sqlite3_aggregate_context() is normally 4430** called once for each invocation of the xStep callback and then one 4431** last time when the xFinal callback is invoked. ^(When no rows match 4432** an aggregate query, the xStep() callback of the aggregate function 4433** implementation is never called and xFinal() is called exactly once. 4434** In those cases, sqlite3_aggregate_context() might be called for the 4435** first time from within xFinal().)^ 4436** 4437** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4438** when first called if N is less than or equal to zero or if a memory 4439** allocate error occurs. 4440** 4441** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4442** determined by the N parameter on first successful call. Changing the 4443** value of N in subsequent call to sqlite3_aggregate_context() within 4444** the same aggregate function instance will not resize the memory 4445** allocation.)^ Within the xFinal callback, it is customary to set 4446** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4447** pointless memory allocations occur. 4448** 4449** ^SQLite automatically frees the memory allocated by 4450** sqlite3_aggregate_context() when the aggregate query concludes. 4451** 4452** The first parameter must be a copy of the 4453** [sqlite3_context | SQL function context] that is the first parameter 4454** to the xStep or xFinal callback routine that implements the aggregate 4455** function. 4456** 4457** This routine must be called from the same thread in which 4458** the aggregate SQL function is running. 4459*/ 4460void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4461 4462/* 4463** CAPI3REF: User Data For Functions 4464** METHOD: sqlite3_context 4465** 4466** ^The sqlite3_user_data() interface returns a copy of 4467** the pointer that was the pUserData parameter (the 5th parameter) 4468** of the [sqlite3_create_function()] 4469** and [sqlite3_create_function16()] routines that originally 4470** registered the application defined function. 4471** 4472** This routine must be called from the same thread in which 4473** the application-defined function is running. 4474*/ 4475void *sqlite3_user_data(sqlite3_context*); 4476 4477/* 4478** CAPI3REF: Database Connection For Functions 4479** METHOD: sqlite3_context 4480** 4481** ^The sqlite3_context_db_handle() interface returns a copy of 4482** the pointer to the [database connection] (the 1st parameter) 4483** of the [sqlite3_create_function()] 4484** and [sqlite3_create_function16()] routines that originally 4485** registered the application defined function. 4486*/ 4487sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4488 4489/* 4490** CAPI3REF: Function Auxiliary Data 4491** METHOD: sqlite3_context 4492** 4493** These functions may be used by (non-aggregate) SQL functions to 4494** associate metadata with argument values. If the same value is passed to 4495** multiple invocations of the same SQL function during query execution, under 4496** some circumstances the associated metadata may be preserved. An example 4497** of where this might be useful is in a regular-expression matching 4498** function. The compiled version of the regular expression can be stored as 4499** metadata associated with the pattern string. 4500** Then as long as the pattern string remains the same, 4501** the compiled regular expression can be reused on multiple 4502** invocations of the same function. 4503** 4504** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4505** associated by the sqlite3_set_auxdata() function with the Nth argument 4506** value to the application-defined function. ^If there is no metadata 4507** associated with the function argument, this sqlite3_get_auxdata() interface 4508** returns a NULL pointer. 4509** 4510** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4511** argument of the application-defined function. ^Subsequent 4512** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4513** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4514** NULL if the metadata has been discarded. 4515** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4516** SQLite will invoke the destructor function X with parameter P exactly 4517** once, when the metadata is discarded. 4518** SQLite is free to discard the metadata at any time, including: <ul> 4519** <li> when the corresponding function parameter changes, or 4520** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4521** SQL statement, or 4522** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or 4523** <li> during the original sqlite3_set_auxdata() call when a memory 4524** allocation error occurs. </ul>)^ 4525** 4526** Note the last bullet in particular. The destructor X in 4527** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4528** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4529** should be called near the end of the function implementation and the 4530** function implementation should not make any use of P after 4531** sqlite3_set_auxdata() has been called. 4532** 4533** ^(In practice, metadata is preserved between function calls for 4534** function parameters that are compile-time constants, including literal 4535** values and [parameters] and expressions composed from the same.)^ 4536** 4537** These routines must be called from the same thread in which 4538** the SQL function is running. 4539*/ 4540void *sqlite3_get_auxdata(sqlite3_context*, int N); 4541void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4542 4543 4544/* 4545** CAPI3REF: Constants Defining Special Destructor Behavior 4546** 4547** These are special values for the destructor that is passed in as the 4548** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4549** argument is SQLITE_STATIC, it means that the content pointer is constant 4550** and will never change. It does not need to be destroyed. ^The 4551** SQLITE_TRANSIENT value means that the content will likely change in 4552** the near future and that SQLite should make its own private copy of 4553** the content before returning. 4554** 4555** The typedef is necessary to work around problems in certain 4556** C++ compilers. 4557*/ 4558typedef void (*sqlite3_destructor_type)(void*); 4559#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4560#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4561 4562/* 4563** CAPI3REF: Setting The Result Of An SQL Function 4564** METHOD: sqlite3_context 4565** 4566** These routines are used by the xFunc or xFinal callbacks that 4567** implement SQL functions and aggregates. See 4568** [sqlite3_create_function()] and [sqlite3_create_function16()] 4569** for additional information. 4570** 4571** These functions work very much like the [parameter binding] family of 4572** functions used to bind values to host parameters in prepared statements. 4573** Refer to the [SQL parameter] documentation for additional information. 4574** 4575** ^The sqlite3_result_blob() interface sets the result from 4576** an application-defined function to be the BLOB whose content is pointed 4577** to by the second parameter and which is N bytes long where N is the 4578** third parameter. 4579** 4580** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 4581** interfaces set the result of the application-defined function to be 4582** a BLOB containing all zero bytes and N bytes in size. 4583** 4584** ^The sqlite3_result_double() interface sets the result from 4585** an application-defined function to be a floating point value specified 4586** by its 2nd argument. 4587** 4588** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4589** cause the implemented SQL function to throw an exception. 4590** ^SQLite uses the string pointed to by the 4591** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4592** as the text of an error message. ^SQLite interprets the error 4593** message string from sqlite3_result_error() as UTF-8. ^SQLite 4594** interprets the string from sqlite3_result_error16() as UTF-16 in native 4595** byte order. ^If the third parameter to sqlite3_result_error() 4596** or sqlite3_result_error16() is negative then SQLite takes as the error 4597** message all text up through the first zero character. 4598** ^If the third parameter to sqlite3_result_error() or 4599** sqlite3_result_error16() is non-negative then SQLite takes that many 4600** bytes (not characters) from the 2nd parameter as the error message. 4601** ^The sqlite3_result_error() and sqlite3_result_error16() 4602** routines make a private copy of the error message text before 4603** they return. Hence, the calling function can deallocate or 4604** modify the text after they return without harm. 4605** ^The sqlite3_result_error_code() function changes the error code 4606** returned by SQLite as a result of an error in a function. ^By default, 4607** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4608** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4609** 4610** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4611** error indicating that a string or BLOB is too long to represent. 4612** 4613** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4614** error indicating that a memory allocation failed. 4615** 4616** ^The sqlite3_result_int() interface sets the return value 4617** of the application-defined function to be the 32-bit signed integer 4618** value given in the 2nd argument. 4619** ^The sqlite3_result_int64() interface sets the return value 4620** of the application-defined function to be the 64-bit signed integer 4621** value given in the 2nd argument. 4622** 4623** ^The sqlite3_result_null() interface sets the return value 4624** of the application-defined function to be NULL. 4625** 4626** ^The sqlite3_result_text(), sqlite3_result_text16(), 4627** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4628** set the return value of the application-defined function to be 4629** a text string which is represented as UTF-8, UTF-16 native byte order, 4630** UTF-16 little endian, or UTF-16 big endian, respectively. 4631** ^The sqlite3_result_text64() interface sets the return value of an 4632** application-defined function to be a text string in an encoding 4633** specified by the fifth (and last) parameter, which must be one 4634** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 4635** ^SQLite takes the text result from the application from 4636** the 2nd parameter of the sqlite3_result_text* interfaces. 4637** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4638** is negative, then SQLite takes result text from the 2nd parameter 4639** through the first zero character. 4640** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4641** is non-negative, then as many bytes (not characters) of the text 4642** pointed to by the 2nd parameter are taken as the application-defined 4643** function result. If the 3rd parameter is non-negative, then it 4644** must be the byte offset into the string where the NUL terminator would 4645** appear if the string where NUL terminated. If any NUL characters occur 4646** in the string at a byte offset that is less than the value of the 3rd 4647** parameter, then the resulting string will contain embedded NULs and the 4648** result of expressions operating on strings with embedded NULs is undefined. 4649** ^If the 4th parameter to the sqlite3_result_text* interfaces 4650** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4651** function as the destructor on the text or BLOB result when it has 4652** finished using that result. 4653** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4654** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4655** assumes that the text or BLOB result is in constant space and does not 4656** copy the content of the parameter nor call a destructor on the content 4657** when it has finished using that result. 4658** ^If the 4th parameter to the sqlite3_result_text* interfaces 4659** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4660** then SQLite makes a copy of the result into space obtained from 4661** from [sqlite3_malloc()] before it returns. 4662** 4663** ^The sqlite3_result_value() interface sets the result of 4664** the application-defined function to be a copy of the 4665** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4666** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4667** so that the [sqlite3_value] specified in the parameter may change or 4668** be deallocated after sqlite3_result_value() returns without harm. 4669** ^A [protected sqlite3_value] object may always be used where an 4670** [unprotected sqlite3_value] object is required, so either 4671** kind of [sqlite3_value] object can be used with this interface. 4672** 4673** If these routines are called from within the different thread 4674** than the one containing the application-defined function that received 4675** the [sqlite3_context] pointer, the results are undefined. 4676*/ 4677void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4678void sqlite3_result_blob64(sqlite3_context*,const void*, 4679 sqlite3_uint64,void(*)(void*)); 4680void sqlite3_result_double(sqlite3_context*, double); 4681void sqlite3_result_error(sqlite3_context*, const char*, int); 4682void sqlite3_result_error16(sqlite3_context*, const void*, int); 4683void sqlite3_result_error_toobig(sqlite3_context*); 4684void sqlite3_result_error_nomem(sqlite3_context*); 4685void sqlite3_result_error_code(sqlite3_context*, int); 4686void sqlite3_result_int(sqlite3_context*, int); 4687void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4688void sqlite3_result_null(sqlite3_context*); 4689void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4690void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 4691 void(*)(void*), unsigned char encoding); 4692void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4693void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4694void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4695void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4696void sqlite3_result_zeroblob(sqlite3_context*, int n); 4697int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 4698 4699 4700/* 4701** CAPI3REF: Setting The Subtype Of An SQL Function 4702** METHOD: sqlite3_context 4703** 4704** The sqlite3_result_subtype(C,T) function causes the subtype of 4705** the result from the [application-defined SQL function] with 4706** [sqlite3_context] C to be the value T. Only the lower 8 bits 4707** of the subtype T are preserved in current versions of SQLite; 4708** higher order bits are discarded. 4709** The number of subtype bytes preserved by SQLite might increase 4710** in future releases of SQLite. 4711*/ 4712void sqlite3_result_subtype(sqlite3_context*,unsigned int); 4713 4714/* 4715** CAPI3REF: Define New Collating Sequences 4716** METHOD: sqlite3 4717** 4718** ^These functions add, remove, or modify a [collation] associated 4719** with the [database connection] specified as the first argument. 4720** 4721** ^The name of the collation is a UTF-8 string 4722** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4723** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4724** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4725** considered to be the same name. 4726** 4727** ^(The third argument (eTextRep) must be one of the constants: 4728** <ul> 4729** <li> [SQLITE_UTF8], 4730** <li> [SQLITE_UTF16LE], 4731** <li> [SQLITE_UTF16BE], 4732** <li> [SQLITE_UTF16], or 4733** <li> [SQLITE_UTF16_ALIGNED]. 4734** </ul>)^ 4735** ^The eTextRep argument determines the encoding of strings passed 4736** to the collating function callback, xCallback. 4737** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4738** force strings to be UTF16 with native byte order. 4739** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4740** on an even byte address. 4741** 4742** ^The fourth argument, pArg, is an application data pointer that is passed 4743** through as the first argument to the collating function callback. 4744** 4745** ^The fifth argument, xCallback, is a pointer to the collating function. 4746** ^Multiple collating functions can be registered using the same name but 4747** with different eTextRep parameters and SQLite will use whichever 4748** function requires the least amount of data transformation. 4749** ^If the xCallback argument is NULL then the collating function is 4750** deleted. ^When all collating functions having the same name are deleted, 4751** that collation is no longer usable. 4752** 4753** ^The collating function callback is invoked with a copy of the pArg 4754** application data pointer and with two strings in the encoding specified 4755** by the eTextRep argument. The collating function must return an 4756** integer that is negative, zero, or positive 4757** if the first string is less than, equal to, or greater than the second, 4758** respectively. A collating function must always return the same answer 4759** given the same inputs. If two or more collating functions are registered 4760** to the same collation name (using different eTextRep values) then all 4761** must give an equivalent answer when invoked with equivalent strings. 4762** The collating function must obey the following properties for all 4763** strings A, B, and C: 4764** 4765** <ol> 4766** <li> If A==B then B==A. 4767** <li> If A==B and B==C then A==C. 4768** <li> If A<B THEN B>A. 4769** <li> If A<B and B<C then A<C. 4770** </ol> 4771** 4772** If a collating function fails any of the above constraints and that 4773** collating function is registered and used, then the behavior of SQLite 4774** is undefined. 4775** 4776** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4777** with the addition that the xDestroy callback is invoked on pArg when 4778** the collating function is deleted. 4779** ^Collating functions are deleted when they are overridden by later 4780** calls to the collation creation functions or when the 4781** [database connection] is closed using [sqlite3_close()]. 4782** 4783** ^The xDestroy callback is <u>not</u> called if the 4784** sqlite3_create_collation_v2() function fails. Applications that invoke 4785** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4786** check the return code and dispose of the application data pointer 4787** themselves rather than expecting SQLite to deal with it for them. 4788** This is different from every other SQLite interface. The inconsistency 4789** is unfortunate but cannot be changed without breaking backwards 4790** compatibility. 4791** 4792** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4793*/ 4794int sqlite3_create_collation( 4795 sqlite3*, 4796 const char *zName, 4797 int eTextRep, 4798 void *pArg, 4799 int(*xCompare)(void*,int,const void*,int,const void*) 4800); 4801int sqlite3_create_collation_v2( 4802 sqlite3*, 4803 const char *zName, 4804 int eTextRep, 4805 void *pArg, 4806 int(*xCompare)(void*,int,const void*,int,const void*), 4807 void(*xDestroy)(void*) 4808); 4809int sqlite3_create_collation16( 4810 sqlite3*, 4811 const void *zName, 4812 int eTextRep, 4813 void *pArg, 4814 int(*xCompare)(void*,int,const void*,int,const void*) 4815); 4816 4817/* 4818** CAPI3REF: Collation Needed Callbacks 4819** METHOD: sqlite3 4820** 4821** ^To avoid having to register all collation sequences before a database 4822** can be used, a single callback function may be registered with the 4823** [database connection] to be invoked whenever an undefined collation 4824** sequence is required. 4825** 4826** ^If the function is registered using the sqlite3_collation_needed() API, 4827** then it is passed the names of undefined collation sequences as strings 4828** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4829** the names are passed as UTF-16 in machine native byte order. 4830** ^A call to either function replaces the existing collation-needed callback. 4831** 4832** ^(When the callback is invoked, the first argument passed is a copy 4833** of the second argument to sqlite3_collation_needed() or 4834** sqlite3_collation_needed16(). The second argument is the database 4835** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4836** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4837** sequence function required. The fourth parameter is the name of the 4838** required collation sequence.)^ 4839** 4840** The callback function should register the desired collation using 4841** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4842** [sqlite3_create_collation_v2()]. 4843*/ 4844int sqlite3_collation_needed( 4845 sqlite3*, 4846 void*, 4847 void(*)(void*,sqlite3*,int eTextRep,const char*) 4848); 4849int sqlite3_collation_needed16( 4850 sqlite3*, 4851 void*, 4852 void(*)(void*,sqlite3*,int eTextRep,const void*) 4853); 4854 4855#ifdef SQLITE_HAS_CODEC 4856/* 4857** Specify the key for an encrypted database. This routine should be 4858** called right after sqlite3_open(). 4859** 4860** The code to implement this API is not available in the public release 4861** of SQLite. 4862*/ 4863int sqlite3_key( 4864 sqlite3 *db, /* Database to be rekeyed */ 4865 const void *pKey, int nKey /* The key */ 4866); 4867int sqlite3_key_v2( 4868 sqlite3 *db, /* Database to be rekeyed */ 4869 const char *zDbName, /* Name of the database */ 4870 const void *pKey, int nKey /* The key */ 4871); 4872 4873/* 4874** Change the key on an open database. If the current database is not 4875** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4876** database is decrypted. 4877** 4878** The code to implement this API is not available in the public release 4879** of SQLite. 4880*/ 4881int sqlite3_rekey( 4882 sqlite3 *db, /* Database to be rekeyed */ 4883 const void *pKey, int nKey /* The new key */ 4884); 4885int sqlite3_rekey_v2( 4886 sqlite3 *db, /* Database to be rekeyed */ 4887 const char *zDbName, /* Name of the database */ 4888 const void *pKey, int nKey /* The new key */ 4889); 4890 4891/* 4892** Specify the activation key for a SEE database. Unless 4893** activated, none of the SEE routines will work. 4894*/ 4895void sqlite3_activate_see( 4896 const char *zPassPhrase /* Activation phrase */ 4897); 4898#endif 4899 4900#ifdef SQLITE_ENABLE_CEROD 4901/* 4902** Specify the activation key for a CEROD database. Unless 4903** activated, none of the CEROD routines will work. 4904*/ 4905void sqlite3_activate_cerod( 4906 const char *zPassPhrase /* Activation phrase */ 4907); 4908#endif 4909 4910/* 4911** CAPI3REF: Suspend Execution For A Short Time 4912** 4913** The sqlite3_sleep() function causes the current thread to suspend execution 4914** for at least a number of milliseconds specified in its parameter. 4915** 4916** If the operating system does not support sleep requests with 4917** millisecond time resolution, then the time will be rounded up to 4918** the nearest second. The number of milliseconds of sleep actually 4919** requested from the operating system is returned. 4920** 4921** ^SQLite implements this interface by calling the xSleep() 4922** method of the default [sqlite3_vfs] object. If the xSleep() method 4923** of the default VFS is not implemented correctly, or not implemented at 4924** all, then the behavior of sqlite3_sleep() may deviate from the description 4925** in the previous paragraphs. 4926*/ 4927int sqlite3_sleep(int); 4928 4929/* 4930** CAPI3REF: Name Of The Folder Holding Temporary Files 4931** 4932** ^(If this global variable is made to point to a string which is 4933** the name of a folder (a.k.a. directory), then all temporary files 4934** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4935** will be placed in that directory.)^ ^If this variable 4936** is a NULL pointer, then SQLite performs a search for an appropriate 4937** temporary file directory. 4938** 4939** Applications are strongly discouraged from using this global variable. 4940** It is required to set a temporary folder on Windows Runtime (WinRT). 4941** But for all other platforms, it is highly recommended that applications 4942** neither read nor write this variable. This global variable is a relic 4943** that exists for backwards compatibility of legacy applications and should 4944** be avoided in new projects. 4945** 4946** It is not safe to read or modify this variable in more than one 4947** thread at a time. It is not safe to read or modify this variable 4948** if a [database connection] is being used at the same time in a separate 4949** thread. 4950** It is intended that this variable be set once 4951** as part of process initialization and before any SQLite interface 4952** routines have been called and that this variable remain unchanged 4953** thereafter. 4954** 4955** ^The [temp_store_directory pragma] may modify this variable and cause 4956** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4957** the [temp_store_directory pragma] always assumes that any string 4958** that this variable points to is held in memory obtained from 4959** [sqlite3_malloc] and the pragma may attempt to free that memory 4960** using [sqlite3_free]. 4961** Hence, if this variable is modified directly, either it should be 4962** made NULL or made to point to memory obtained from [sqlite3_malloc] 4963** or else the use of the [temp_store_directory pragma] should be avoided. 4964** Except when requested by the [temp_store_directory pragma], SQLite 4965** does not free the memory that sqlite3_temp_directory points to. If 4966** the application wants that memory to be freed, it must do 4967** so itself, taking care to only do so after all [database connection] 4968** objects have been destroyed. 4969** 4970** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4971** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4972** features that require the use of temporary files may fail. Here is an 4973** example of how to do this using C++ with the Windows Runtime: 4974** 4975** <blockquote><pre> 4976** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4977** TemporaryFolder->Path->Data(); 4978** char zPathBuf[MAX_PATH + 1]; 4979** memset(zPathBuf, 0, sizeof(zPathBuf)); 4980** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4981** NULL, NULL); 4982** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4983** </pre></blockquote> 4984*/ 4985SQLITE_EXTERN char *sqlite3_temp_directory; 4986 4987/* 4988** CAPI3REF: Name Of The Folder Holding Database Files 4989** 4990** ^(If this global variable is made to point to a string which is 4991** the name of a folder (a.k.a. directory), then all database files 4992** specified with a relative pathname and created or accessed by 4993** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4994** to be relative to that directory.)^ ^If this variable is a NULL 4995** pointer, then SQLite assumes that all database files specified 4996** with a relative pathname are relative to the current directory 4997** for the process. Only the windows VFS makes use of this global 4998** variable; it is ignored by the unix VFS. 4999** 5000** Changing the value of this variable while a database connection is 5001** open can result in a corrupt database. 5002** 5003** It is not safe to read or modify this variable in more than one 5004** thread at a time. It is not safe to read or modify this variable 5005** if a [database connection] is being used at the same time in a separate 5006** thread. 5007** It is intended that this variable be set once 5008** as part of process initialization and before any SQLite interface 5009** routines have been called and that this variable remain unchanged 5010** thereafter. 5011** 5012** ^The [data_store_directory pragma] may modify this variable and cause 5013** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5014** the [data_store_directory pragma] always assumes that any string 5015** that this variable points to is held in memory obtained from 5016** [sqlite3_malloc] and the pragma may attempt to free that memory 5017** using [sqlite3_free]. 5018** Hence, if this variable is modified directly, either it should be 5019** made NULL or made to point to memory obtained from [sqlite3_malloc] 5020** or else the use of the [data_store_directory pragma] should be avoided. 5021*/ 5022SQLITE_EXTERN char *sqlite3_data_directory; 5023 5024/* 5025** CAPI3REF: Test For Auto-Commit Mode 5026** KEYWORDS: {autocommit mode} 5027** METHOD: sqlite3 5028** 5029** ^The sqlite3_get_autocommit() interface returns non-zero or 5030** zero if the given database connection is or is not in autocommit mode, 5031** respectively. ^Autocommit mode is on by default. 5032** ^Autocommit mode is disabled by a [BEGIN] statement. 5033** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5034** 5035** If certain kinds of errors occur on a statement within a multi-statement 5036** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5037** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5038** transaction might be rolled back automatically. The only way to 5039** find out whether SQLite automatically rolled back the transaction after 5040** an error is to use this function. 5041** 5042** If another thread changes the autocommit status of the database 5043** connection while this routine is running, then the return value 5044** is undefined. 5045*/ 5046int sqlite3_get_autocommit(sqlite3*); 5047 5048/* 5049** CAPI3REF: Find The Database Handle Of A Prepared Statement 5050** METHOD: sqlite3_stmt 5051** 5052** ^The sqlite3_db_handle interface returns the [database connection] handle 5053** to which a [prepared statement] belongs. ^The [database connection] 5054** returned by sqlite3_db_handle is the same [database connection] 5055** that was the first argument 5056** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5057** create the statement in the first place. 5058*/ 5059sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5060 5061/* 5062** CAPI3REF: Return The Filename For A Database Connection 5063** METHOD: sqlite3 5064** 5065** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5066** associated with database N of connection D. ^The main database file 5067** has the name "main". If there is no attached database N on the database 5068** connection D, or if database N is a temporary or in-memory database, then 5069** a NULL pointer is returned. 5070** 5071** ^The filename returned by this function is the output of the 5072** xFullPathname method of the [VFS]. ^In other words, the filename 5073** will be an absolute pathname, even if the filename used 5074** to open the database originally was a URI or relative pathname. 5075*/ 5076const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5077 5078/* 5079** CAPI3REF: Determine if a database is read-only 5080** METHOD: sqlite3 5081** 5082** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5083** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5084** the name of a database on connection D. 5085*/ 5086int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5087 5088/* 5089** CAPI3REF: Find the next prepared statement 5090** METHOD: sqlite3 5091** 5092** ^This interface returns a pointer to the next [prepared statement] after 5093** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5094** then this interface returns a pointer to the first prepared statement 5095** associated with the database connection pDb. ^If no prepared statement 5096** satisfies the conditions of this routine, it returns NULL. 5097** 5098** The [database connection] pointer D in a call to 5099** [sqlite3_next_stmt(D,S)] must refer to an open database 5100** connection and in particular must not be a NULL pointer. 5101*/ 5102sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5103 5104/* 5105** CAPI3REF: Commit And Rollback Notification Callbacks 5106** METHOD: sqlite3 5107** 5108** ^The sqlite3_commit_hook() interface registers a callback 5109** function to be invoked whenever a transaction is [COMMIT | committed]. 5110** ^Any callback set by a previous call to sqlite3_commit_hook() 5111** for the same database connection is overridden. 5112** ^The sqlite3_rollback_hook() interface registers a callback 5113** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5114** ^Any callback set by a previous call to sqlite3_rollback_hook() 5115** for the same database connection is overridden. 5116** ^The pArg argument is passed through to the callback. 5117** ^If the callback on a commit hook function returns non-zero, 5118** then the commit is converted into a rollback. 5119** 5120** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5121** return the P argument from the previous call of the same function 5122** on the same [database connection] D, or NULL for 5123** the first call for each function on D. 5124** 5125** The commit and rollback hook callbacks are not reentrant. 5126** The callback implementation must not do anything that will modify 5127** the database connection that invoked the callback. Any actions 5128** to modify the database connection must be deferred until after the 5129** completion of the [sqlite3_step()] call that triggered the commit 5130** or rollback hook in the first place. 5131** Note that running any other SQL statements, including SELECT statements, 5132** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5133** the database connections for the meaning of "modify" in this paragraph. 5134** 5135** ^Registering a NULL function disables the callback. 5136** 5137** ^When the commit hook callback routine returns zero, the [COMMIT] 5138** operation is allowed to continue normally. ^If the commit hook 5139** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5140** ^The rollback hook is invoked on a rollback that results from a commit 5141** hook returning non-zero, just as it would be with any other rollback. 5142** 5143** ^For the purposes of this API, a transaction is said to have been 5144** rolled back if an explicit "ROLLBACK" statement is executed, or 5145** an error or constraint causes an implicit rollback to occur. 5146** ^The rollback callback is not invoked if a transaction is 5147** automatically rolled back because the database connection is closed. 5148** 5149** See also the [sqlite3_update_hook()] interface. 5150*/ 5151void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5152void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5153 5154/* 5155** CAPI3REF: Data Change Notification Callbacks 5156** METHOD: sqlite3 5157** 5158** ^The sqlite3_update_hook() interface registers a callback function 5159** with the [database connection] identified by the first argument 5160** to be invoked whenever a row is updated, inserted or deleted in 5161** a rowid table. 5162** ^Any callback set by a previous call to this function 5163** for the same database connection is overridden. 5164** 5165** ^The second argument is a pointer to the function to invoke when a 5166** row is updated, inserted or deleted in a rowid table. 5167** ^The first argument to the callback is a copy of the third argument 5168** to sqlite3_update_hook(). 5169** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5170** or [SQLITE_UPDATE], depending on the operation that caused the callback 5171** to be invoked. 5172** ^The third and fourth arguments to the callback contain pointers to the 5173** database and table name containing the affected row. 5174** ^The final callback parameter is the [rowid] of the row. 5175** ^In the case of an update, this is the [rowid] after the update takes place. 5176** 5177** ^(The update hook is not invoked when internal system tables are 5178** modified (i.e. sqlite_master and sqlite_sequence).)^ 5179** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5180** 5181** ^In the current implementation, the update hook 5182** is not invoked when duplication rows are deleted because of an 5183** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5184** invoked when rows are deleted using the [truncate optimization]. 5185** The exceptions defined in this paragraph might change in a future 5186** release of SQLite. 5187** 5188** The update hook implementation must not do anything that will modify 5189** the database connection that invoked the update hook. Any actions 5190** to modify the database connection must be deferred until after the 5191** completion of the [sqlite3_step()] call that triggered the update hook. 5192** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5193** database connections for the meaning of "modify" in this paragraph. 5194** 5195** ^The sqlite3_update_hook(D,C,P) function 5196** returns the P argument from the previous call 5197** on the same [database connection] D, or NULL for 5198** the first call on D. 5199** 5200** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 5201** interfaces. 5202*/ 5203void *sqlite3_update_hook( 5204 sqlite3*, 5205 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5206 void* 5207); 5208 5209/* 5210** CAPI3REF: Enable Or Disable Shared Pager Cache 5211** 5212** ^(This routine enables or disables the sharing of the database cache 5213** and schema data structures between [database connection | connections] 5214** to the same database. Sharing is enabled if the argument is true 5215** and disabled if the argument is false.)^ 5216** 5217** ^Cache sharing is enabled and disabled for an entire process. 5218** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 5219** sharing was enabled or disabled for each thread separately. 5220** 5221** ^(The cache sharing mode set by this interface effects all subsequent 5222** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5223** Existing database connections continue use the sharing mode 5224** that was in effect at the time they were opened.)^ 5225** 5226** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5227** successfully. An [error code] is returned otherwise.)^ 5228** 5229** ^Shared cache is disabled by default. But this might change in 5230** future releases of SQLite. Applications that care about shared 5231** cache setting should set it explicitly. 5232** 5233** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5234** and will always return SQLITE_MISUSE. On those systems, 5235** shared cache mode should be enabled per-database connection via 5236** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5237** 5238** This interface is threadsafe on processors where writing a 5239** 32-bit integer is atomic. 5240** 5241** See Also: [SQLite Shared-Cache Mode] 5242*/ 5243int sqlite3_enable_shared_cache(int); 5244 5245/* 5246** CAPI3REF: Attempt To Free Heap Memory 5247** 5248** ^The sqlite3_release_memory() interface attempts to free N bytes 5249** of heap memory by deallocating non-essential memory allocations 5250** held by the database library. Memory used to cache database 5251** pages to improve performance is an example of non-essential memory. 5252** ^sqlite3_release_memory() returns the number of bytes actually freed, 5253** which might be more or less than the amount requested. 5254** ^The sqlite3_release_memory() routine is a no-op returning zero 5255** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5256** 5257** See also: [sqlite3_db_release_memory()] 5258*/ 5259int sqlite3_release_memory(int); 5260 5261/* 5262** CAPI3REF: Free Memory Used By A Database Connection 5263** METHOD: sqlite3 5264** 5265** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5266** memory as possible from database connection D. Unlike the 5267** [sqlite3_release_memory()] interface, this interface is in effect even 5268** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5269** omitted. 5270** 5271** See also: [sqlite3_release_memory()] 5272*/ 5273int sqlite3_db_release_memory(sqlite3*); 5274 5275/* 5276** CAPI3REF: Impose A Limit On Heap Size 5277** 5278** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5279** soft limit on the amount of heap memory that may be allocated by SQLite. 5280** ^SQLite strives to keep heap memory utilization below the soft heap 5281** limit by reducing the number of pages held in the page cache 5282** as heap memory usages approaches the limit. 5283** ^The soft heap limit is "soft" because even though SQLite strives to stay 5284** below the limit, it will exceed the limit rather than generate 5285** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5286** is advisory only. 5287** 5288** ^The return value from sqlite3_soft_heap_limit64() is the size of 5289** the soft heap limit prior to the call, or negative in the case of an 5290** error. ^If the argument N is negative 5291** then no change is made to the soft heap limit. Hence, the current 5292** size of the soft heap limit can be determined by invoking 5293** sqlite3_soft_heap_limit64() with a negative argument. 5294** 5295** ^If the argument N is zero then the soft heap limit is disabled. 5296** 5297** ^(The soft heap limit is not enforced in the current implementation 5298** if one or more of following conditions are true: 5299** 5300** <ul> 5301** <li> The soft heap limit is set to zero. 5302** <li> Memory accounting is disabled using a combination of the 5303** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5304** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5305** <li> An alternative page cache implementation is specified using 5306** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5307** <li> The page cache allocates from its own memory pool supplied 5308** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5309** from the heap. 5310** </ul>)^ 5311** 5312** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 5313** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5314** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5315** the soft heap limit is enforced on every memory allocation. Without 5316** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5317** when memory is allocated by the page cache. Testing suggests that because 5318** the page cache is the predominate memory user in SQLite, most 5319** applications will achieve adequate soft heap limit enforcement without 5320** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5321** 5322** The circumstances under which SQLite will enforce the soft heap limit may 5323** changes in future releases of SQLite. 5324*/ 5325sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5326 5327/* 5328** CAPI3REF: Deprecated Soft Heap Limit Interface 5329** DEPRECATED 5330** 5331** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5332** interface. This routine is provided for historical compatibility 5333** only. All new applications should use the 5334** [sqlite3_soft_heap_limit64()] interface rather than this one. 5335*/ 5336SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5337 5338 5339/* 5340** CAPI3REF: Extract Metadata About A Column Of A Table 5341** METHOD: sqlite3 5342** 5343** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5344** information about column C of table T in database D 5345** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5346** interface returns SQLITE_OK and fills in the non-NULL pointers in 5347** the final five arguments with appropriate values if the specified 5348** column exists. ^The sqlite3_table_column_metadata() interface returns 5349** SQLITE_ERROR and if the specified column does not exist. 5350** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5351** NULL pointer, then this routine simply checks for the existance of the 5352** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5353** does not. 5354** 5355** ^The column is identified by the second, third and fourth parameters to 5356** this function. ^(The second parameter is either the name of the database 5357** (i.e. "main", "temp", or an attached database) containing the specified 5358** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5359** for the table using the same algorithm used by the database engine to 5360** resolve unqualified table references. 5361** 5362** ^The third and fourth parameters to this function are the table and column 5363** name of the desired column, respectively. 5364** 5365** ^Metadata is returned by writing to the memory locations passed as the 5th 5366** and subsequent parameters to this function. ^Any of these arguments may be 5367** NULL, in which case the corresponding element of metadata is omitted. 5368** 5369** ^(<blockquote> 5370** <table border="1"> 5371** <tr><th> Parameter <th> Output<br>Type <th> Description 5372** 5373** <tr><td> 5th <td> const char* <td> Data type 5374** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5375** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5376** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5377** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5378** </table> 5379** </blockquote>)^ 5380** 5381** ^The memory pointed to by the character pointers returned for the 5382** declaration type and collation sequence is valid until the next 5383** call to any SQLite API function. 5384** 5385** ^If the specified table is actually a view, an [error code] is returned. 5386** 5387** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5388** is not a [WITHOUT ROWID] table and an 5389** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5390** parameters are set for the explicitly declared column. ^(If there is no 5391** [INTEGER PRIMARY KEY] column, then the outputs 5392** for the [rowid] are set as follows: 5393** 5394** <pre> 5395** data type: "INTEGER" 5396** collation sequence: "BINARY" 5397** not null: 0 5398** primary key: 1 5399** auto increment: 0 5400** </pre>)^ 5401** 5402** ^This function causes all database schemas to be read from disk and 5403** parsed, if that has not already been done, and returns an error if 5404** any errors are encountered while loading the schema. 5405*/ 5406int sqlite3_table_column_metadata( 5407 sqlite3 *db, /* Connection handle */ 5408 const char *zDbName, /* Database name or NULL */ 5409 const char *zTableName, /* Table name */ 5410 const char *zColumnName, /* Column name */ 5411 char const **pzDataType, /* OUTPUT: Declared data type */ 5412 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5413 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5414 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5415 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5416); 5417 5418/* 5419** CAPI3REF: Load An Extension 5420** METHOD: sqlite3 5421** 5422** ^This interface loads an SQLite extension library from the named file. 5423** 5424** ^The sqlite3_load_extension() interface attempts to load an 5425** [SQLite extension] library contained in the file zFile. If 5426** the file cannot be loaded directly, attempts are made to load 5427** with various operating-system specific extensions added. 5428** So for example, if "samplelib" cannot be loaded, then names like 5429** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5430** be tried also. 5431** 5432** ^The entry point is zProc. 5433** ^(zProc may be 0, in which case SQLite will try to come up with an 5434** entry point name on its own. It first tries "sqlite3_extension_init". 5435** If that does not work, it constructs a name "sqlite3_X_init" where the 5436** X is consists of the lower-case equivalent of all ASCII alphabetic 5437** characters in the filename from the last "/" to the first following 5438** "." and omitting any initial "lib".)^ 5439** ^The sqlite3_load_extension() interface returns 5440** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5441** ^If an error occurs and pzErrMsg is not 0, then the 5442** [sqlite3_load_extension()] interface shall attempt to 5443** fill *pzErrMsg with error message text stored in memory 5444** obtained from [sqlite3_malloc()]. The calling function 5445** should free this memory by calling [sqlite3_free()]. 5446** 5447** ^Extension loading must be enabled using 5448** [sqlite3_enable_load_extension()] prior to calling this API, 5449** otherwise an error will be returned. 5450** 5451** See also the [load_extension() SQL function]. 5452*/ 5453int sqlite3_load_extension( 5454 sqlite3 *db, /* Load the extension into this database connection */ 5455 const char *zFile, /* Name of the shared library containing extension */ 5456 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5457 char **pzErrMsg /* Put error message here if not 0 */ 5458); 5459 5460/* 5461** CAPI3REF: Enable Or Disable Extension Loading 5462** METHOD: sqlite3 5463** 5464** ^So as not to open security holes in older applications that are 5465** unprepared to deal with [extension loading], and as a means of disabling 5466** [extension loading] while evaluating user-entered SQL, the following API 5467** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5468** 5469** ^Extension loading is off by default. 5470** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5471** to turn extension loading on and call it with onoff==0 to turn 5472** it back off again. 5473*/ 5474int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5475 5476/* 5477** CAPI3REF: Automatically Load Statically Linked Extensions 5478** 5479** ^This interface causes the xEntryPoint() function to be invoked for 5480** each new [database connection] that is created. The idea here is that 5481** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5482** that is to be automatically loaded into all new database connections. 5483** 5484** ^(Even though the function prototype shows that xEntryPoint() takes 5485** no arguments and returns void, SQLite invokes xEntryPoint() with three 5486** arguments and expects and integer result as if the signature of the 5487** entry point where as follows: 5488** 5489** <blockquote><pre> 5490** int xEntryPoint( 5491** sqlite3 *db, 5492** const char **pzErrMsg, 5493** const struct sqlite3_api_routines *pThunk 5494** ); 5495** </pre></blockquote>)^ 5496** 5497** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5498** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5499** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5500** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5501** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5502** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5503** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5504** 5505** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5506** on the list of automatic extensions is a harmless no-op. ^No entry point 5507** will be called more than once for each database connection that is opened. 5508** 5509** See also: [sqlite3_reset_auto_extension()] 5510** and [sqlite3_cancel_auto_extension()] 5511*/ 5512int sqlite3_auto_extension(void (*xEntryPoint)(void)); 5513 5514/* 5515** CAPI3REF: Cancel Automatic Extension Loading 5516** 5517** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5518** initialization routine X that was registered using a prior call to 5519** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5520** routine returns 1 if initialization routine X was successfully 5521** unregistered and it returns 0 if X was not on the list of initialization 5522** routines. 5523*/ 5524int sqlite3_cancel_auto_extension(void (*xEntryPoint)(void)); 5525 5526/* 5527** CAPI3REF: Reset Automatic Extension Loading 5528** 5529** ^This interface disables all automatic extensions previously 5530** registered using [sqlite3_auto_extension()]. 5531*/ 5532void sqlite3_reset_auto_extension(void); 5533 5534/* 5535** The interface to the virtual-table mechanism is currently considered 5536** to be experimental. The interface might change in incompatible ways. 5537** If this is a problem for you, do not use the interface at this time. 5538** 5539** When the virtual-table mechanism stabilizes, we will declare the 5540** interface fixed, support it indefinitely, and remove this comment. 5541*/ 5542 5543/* 5544** Structures used by the virtual table interface 5545*/ 5546typedef struct sqlite3_vtab sqlite3_vtab; 5547typedef struct sqlite3_index_info sqlite3_index_info; 5548typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5549typedef struct sqlite3_module sqlite3_module; 5550 5551/* 5552** CAPI3REF: Virtual Table Object 5553** KEYWORDS: sqlite3_module {virtual table module} 5554** 5555** This structure, sometimes called a "virtual table module", 5556** defines the implementation of a [virtual tables]. 5557** This structure consists mostly of methods for the module. 5558** 5559** ^A virtual table module is created by filling in a persistent 5560** instance of this structure and passing a pointer to that instance 5561** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5562** ^The registration remains valid until it is replaced by a different 5563** module or until the [database connection] closes. The content 5564** of this structure must not change while it is registered with 5565** any database connection. 5566*/ 5567struct sqlite3_module { 5568 int iVersion; 5569 int (*xCreate)(sqlite3*, void *pAux, 5570 int argc, const char *const*argv, 5571 sqlite3_vtab **ppVTab, char**); 5572 int (*xConnect)(sqlite3*, void *pAux, 5573 int argc, const char *const*argv, 5574 sqlite3_vtab **ppVTab, char**); 5575 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5576 int (*xDisconnect)(sqlite3_vtab *pVTab); 5577 int (*xDestroy)(sqlite3_vtab *pVTab); 5578 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5579 int (*xClose)(sqlite3_vtab_cursor*); 5580 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5581 int argc, sqlite3_value **argv); 5582 int (*xNext)(sqlite3_vtab_cursor*); 5583 int (*xEof)(sqlite3_vtab_cursor*); 5584 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5585 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5586 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5587 int (*xBegin)(sqlite3_vtab *pVTab); 5588 int (*xSync)(sqlite3_vtab *pVTab); 5589 int (*xCommit)(sqlite3_vtab *pVTab); 5590 int (*xRollback)(sqlite3_vtab *pVTab); 5591 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5592 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5593 void **ppArg); 5594 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5595 /* The methods above are in version 1 of the sqlite_module object. Those 5596 ** below are for version 2 and greater. */ 5597 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5598 int (*xRelease)(sqlite3_vtab *pVTab, int); 5599 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5600}; 5601 5602/* 5603** CAPI3REF: Virtual Table Indexing Information 5604** KEYWORDS: sqlite3_index_info 5605** 5606** The sqlite3_index_info structure and its substructures is used as part 5607** of the [virtual table] interface to 5608** pass information into and receive the reply from the [xBestIndex] 5609** method of a [virtual table module]. The fields under **Inputs** are the 5610** inputs to xBestIndex and are read-only. xBestIndex inserts its 5611** results into the **Outputs** fields. 5612** 5613** ^(The aConstraint[] array records WHERE clause constraints of the form: 5614** 5615** <blockquote>column OP expr</blockquote> 5616** 5617** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5618** stored in aConstraint[].op using one of the 5619** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5620** ^(The index of the column is stored in 5621** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5622** expr on the right-hand side can be evaluated (and thus the constraint 5623** is usable) and false if it cannot.)^ 5624** 5625** ^The optimizer automatically inverts terms of the form "expr OP column" 5626** and makes other simplifications to the WHERE clause in an attempt to 5627** get as many WHERE clause terms into the form shown above as possible. 5628** ^The aConstraint[] array only reports WHERE clause terms that are 5629** relevant to the particular virtual table being queried. 5630** 5631** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5632** ^Each term of aOrderBy records a column of the ORDER BY clause. 5633** 5634** The colUsed field indicates which columns of the virtual table may be 5635** required by the current scan. Virtual table columns are numbered from 5636** zero in the order in which they appear within the CREATE TABLE statement 5637** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 5638** the corresponding bit is set within the colUsed mask if the column may be 5639** required by SQLite. If the table has at least 64 columns and any column 5640** to the right of the first 63 is required, then bit 63 of colUsed is also 5641** set. In other words, column iCol may be required if the expression 5642** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 5643** non-zero. 5644** 5645** The [xBestIndex] method must fill aConstraintUsage[] with information 5646** about what parameters to pass to xFilter. ^If argvIndex>0 then 5647** the right-hand side of the corresponding aConstraint[] is evaluated 5648** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5649** is true, then the constraint is assumed to be fully handled by the 5650** virtual table and is not checked again by SQLite.)^ 5651** 5652** ^The idxNum and idxPtr values are recorded and passed into the 5653** [xFilter] method. 5654** ^[sqlite3_free()] is used to free idxPtr if and only if 5655** needToFreeIdxPtr is true. 5656** 5657** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5658** the correct order to satisfy the ORDER BY clause so that no separate 5659** sorting step is required. 5660** 5661** ^The estimatedCost value is an estimate of the cost of a particular 5662** strategy. A cost of N indicates that the cost of the strategy is similar 5663** to a linear scan of an SQLite table with N rows. A cost of log(N) 5664** indicates that the expense of the operation is similar to that of a 5665** binary search on a unique indexed field of an SQLite table with N rows. 5666** 5667** ^The estimatedRows value is an estimate of the number of rows that 5668** will be returned by the strategy. 5669** 5670** The xBestIndex method may optionally populate the idxFlags field with a 5671** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 5672** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 5673** assumes that the strategy may visit at most one row. 5674** 5675** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 5676** SQLite also assumes that if a call to the xUpdate() method is made as 5677** part of the same statement to delete or update a virtual table row and the 5678** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 5679** any database changes. In other words, if the xUpdate() returns 5680** SQLITE_CONSTRAINT, the database contents must be exactly as they were 5681** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 5682** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 5683** the xUpdate method are automatically rolled back by SQLite. 5684** 5685** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 5686** structure for SQLite version 3.8.2. If a virtual table extension is 5687** used with an SQLite version earlier than 3.8.2, the results of attempting 5688** to read or write the estimatedRows field are undefined (but are likely 5689** to included crashing the application). The estimatedRows field should 5690** therefore only be used if [sqlite3_libversion_number()] returns a 5691** value greater than or equal to 3008002. Similarly, the idxFlags field 5692** was added for version 3.9.0. It may therefore only be used if 5693** sqlite3_libversion_number() returns a value greater than or equal to 5694** 3009000. 5695*/ 5696struct sqlite3_index_info { 5697 /* Inputs */ 5698 int nConstraint; /* Number of entries in aConstraint */ 5699 struct sqlite3_index_constraint { 5700 int iColumn; /* Column constrained. -1 for ROWID */ 5701 unsigned char op; /* Constraint operator */ 5702 unsigned char usable; /* True if this constraint is usable */ 5703 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5704 } *aConstraint; /* Table of WHERE clause constraints */ 5705 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5706 struct sqlite3_index_orderby { 5707 int iColumn; /* Column number */ 5708 unsigned char desc; /* True for DESC. False for ASC. */ 5709 } *aOrderBy; /* The ORDER BY clause */ 5710 /* Outputs */ 5711 struct sqlite3_index_constraint_usage { 5712 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5713 unsigned char omit; /* Do not code a test for this constraint */ 5714 } *aConstraintUsage; 5715 int idxNum; /* Number used to identify the index */ 5716 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5717 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5718 int orderByConsumed; /* True if output is already ordered */ 5719 double estimatedCost; /* Estimated cost of using this index */ 5720 /* Fields below are only available in SQLite 3.8.2 and later */ 5721 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 5722 /* Fields below are only available in SQLite 3.9.0 and later */ 5723 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 5724 /* Fields below are only available in SQLite 3.10.0 and later */ 5725 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 5726}; 5727 5728/* 5729** CAPI3REF: Virtual Table Scan Flags 5730*/ 5731#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 5732 5733/* 5734** CAPI3REF: Virtual Table Constraint Operator Codes 5735** 5736** These macros defined the allowed values for the 5737** [sqlite3_index_info].aConstraint[].op field. Each value represents 5738** an operator that is part of a constraint term in the wHERE clause of 5739** a query that uses a [virtual table]. 5740*/ 5741#define SQLITE_INDEX_CONSTRAINT_EQ 2 5742#define SQLITE_INDEX_CONSTRAINT_GT 4 5743#define SQLITE_INDEX_CONSTRAINT_LE 8 5744#define SQLITE_INDEX_CONSTRAINT_LT 16 5745#define SQLITE_INDEX_CONSTRAINT_GE 32 5746#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5747#define SQLITE_INDEX_CONSTRAINT_LIKE 65 5748#define SQLITE_INDEX_CONSTRAINT_GLOB 66 5749#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 5750 5751/* 5752** CAPI3REF: Register A Virtual Table Implementation 5753** METHOD: sqlite3 5754** 5755** ^These routines are used to register a new [virtual table module] name. 5756** ^Module names must be registered before 5757** creating a new [virtual table] using the module and before using a 5758** preexisting [virtual table] for the module. 5759** 5760** ^The module name is registered on the [database connection] specified 5761** by the first parameter. ^The name of the module is given by the 5762** second parameter. ^The third parameter is a pointer to 5763** the implementation of the [virtual table module]. ^The fourth 5764** parameter is an arbitrary client data pointer that is passed through 5765** into the [xCreate] and [xConnect] methods of the virtual table module 5766** when a new virtual table is be being created or reinitialized. 5767** 5768** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5769** is a pointer to a destructor for the pClientData. ^SQLite will 5770** invoke the destructor function (if it is not NULL) when SQLite 5771** no longer needs the pClientData pointer. ^The destructor will also 5772** be invoked if the call to sqlite3_create_module_v2() fails. 5773** ^The sqlite3_create_module() 5774** interface is equivalent to sqlite3_create_module_v2() with a NULL 5775** destructor. 5776*/ 5777int sqlite3_create_module( 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); 5783int sqlite3_create_module_v2( 5784 sqlite3 *db, /* SQLite connection to register module with */ 5785 const char *zName, /* Name of the module */ 5786 const sqlite3_module *p, /* Methods for the module */ 5787 void *pClientData, /* Client data for xCreate/xConnect */ 5788 void(*xDestroy)(void*) /* Module destructor function */ 5789); 5790 5791/* 5792** CAPI3REF: Virtual Table Instance Object 5793** KEYWORDS: sqlite3_vtab 5794** 5795** Every [virtual table module] implementation uses a subclass 5796** of this object to describe a particular instance 5797** of the [virtual table]. Each subclass will 5798** be tailored to the specific needs of the module implementation. 5799** The purpose of this superclass is to define certain fields that are 5800** common to all module implementations. 5801** 5802** ^Virtual tables methods can set an error message by assigning a 5803** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5804** take care that any prior string is freed by a call to [sqlite3_free()] 5805** prior to assigning a new string to zErrMsg. ^After the error message 5806** is delivered up to the client application, the string will be automatically 5807** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5808*/ 5809struct sqlite3_vtab { 5810 const sqlite3_module *pModule; /* The module for this virtual table */ 5811 int nRef; /* Number of open cursors */ 5812 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5813 /* Virtual table implementations will typically add additional fields */ 5814}; 5815 5816/* 5817** CAPI3REF: Virtual Table Cursor Object 5818** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5819** 5820** Every [virtual table module] implementation uses a subclass of the 5821** following structure to describe cursors that point into the 5822** [virtual table] and are used 5823** to loop through the virtual table. Cursors are created using the 5824** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5825** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5826** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5827** of the module. Each module implementation will define 5828** the content of a cursor structure to suit its own needs. 5829** 5830** This superclass exists in order to define fields of the cursor that 5831** are common to all implementations. 5832*/ 5833struct sqlite3_vtab_cursor { 5834 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5835 /* Virtual table implementations will typically add additional fields */ 5836}; 5837 5838/* 5839** CAPI3REF: Declare The Schema Of A Virtual Table 5840** 5841** ^The [xCreate] and [xConnect] methods of a 5842** [virtual table module] call this interface 5843** to declare the format (the names and datatypes of the columns) of 5844** the virtual tables they implement. 5845*/ 5846int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5847 5848/* 5849** CAPI3REF: Overload A Function For A Virtual Table 5850** METHOD: sqlite3 5851** 5852** ^(Virtual tables can provide alternative implementations of functions 5853** using the [xFindFunction] method of the [virtual table module]. 5854** But global versions of those functions 5855** must exist in order to be overloaded.)^ 5856** 5857** ^(This API makes sure a global version of a function with a particular 5858** name and number of parameters exists. If no such function exists 5859** before this API is called, a new function is created.)^ ^The implementation 5860** of the new function always causes an exception to be thrown. So 5861** the new function is not good for anything by itself. Its only 5862** purpose is to be a placeholder function that can be overloaded 5863** by a [virtual table]. 5864*/ 5865int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5866 5867/* 5868** The interface to the virtual-table mechanism defined above (back up 5869** to a comment remarkably similar to this one) is currently considered 5870** to be experimental. The interface might change in incompatible ways. 5871** If this is a problem for you, do not use the interface at this time. 5872** 5873** When the virtual-table mechanism stabilizes, we will declare the 5874** interface fixed, support it indefinitely, and remove this comment. 5875*/ 5876 5877/* 5878** CAPI3REF: A Handle To An Open BLOB 5879** KEYWORDS: {BLOB handle} {BLOB handles} 5880** 5881** An instance of this object represents an open BLOB on which 5882** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5883** ^Objects of this type are created by [sqlite3_blob_open()] 5884** and destroyed by [sqlite3_blob_close()]. 5885** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5886** can be used to read or write small subsections of the BLOB. 5887** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5888*/ 5889typedef struct sqlite3_blob sqlite3_blob; 5890 5891/* 5892** CAPI3REF: Open A BLOB For Incremental I/O 5893** METHOD: sqlite3 5894** CONSTRUCTOR: sqlite3_blob 5895** 5896** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5897** in row iRow, column zColumn, table zTable in database zDb; 5898** in other words, the same BLOB that would be selected by: 5899** 5900** <pre> 5901** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5902** </pre>)^ 5903** 5904** ^(Parameter zDb is not the filename that contains the database, but 5905** rather the symbolic name of the database. For attached databases, this is 5906** the name that appears after the AS keyword in the [ATTACH] statement. 5907** For the main database file, the database name is "main". For TEMP 5908** tables, the database name is "temp".)^ 5909** 5910** ^If the flags parameter is non-zero, then the BLOB is opened for read 5911** and write access. ^If the flags parameter is zero, the BLOB is opened for 5912** read-only access. 5913** 5914** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 5915** in *ppBlob. Otherwise an [error code] is returned and, unless the error 5916** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 5917** the API is not misused, it is always safe to call [sqlite3_blob_close()] 5918** on *ppBlob after this function it returns. 5919** 5920** This function fails with SQLITE_ERROR if any of the following are true: 5921** <ul> 5922** <li> ^(Database zDb does not exist)^, 5923** <li> ^(Table zTable does not exist within database zDb)^, 5924** <li> ^(Table zTable is a WITHOUT ROWID table)^, 5925** <li> ^(Column zColumn does not exist)^, 5926** <li> ^(Row iRow is not present in the table)^, 5927** <li> ^(The specified column of row iRow contains a value that is not 5928** a TEXT or BLOB value)^, 5929** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 5930** constraint and the blob is being opened for read/write access)^, 5931** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 5932** column zColumn is part of a [child key] definition and the blob is 5933** being opened for read/write access)^. 5934** </ul> 5935** 5936** ^Unless it returns SQLITE_MISUSE, this function sets the 5937** [database connection] error code and message accessible via 5938** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 5939** 5940** 5941** ^(If the row that a BLOB handle points to is modified by an 5942** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5943** then the BLOB handle is marked as "expired". 5944** This is true if any column of the row is changed, even a column 5945** other than the one the BLOB handle is open on.)^ 5946** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5947** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5948** ^(Changes written into a BLOB prior to the BLOB expiring are not 5949** rolled back by the expiration of the BLOB. Such changes will eventually 5950** commit if the transaction continues to completion.)^ 5951** 5952** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5953** the opened blob. ^The size of a blob may not be changed by this 5954** interface. Use the [UPDATE] SQL command to change the size of a 5955** blob. 5956** 5957** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5958** and the built-in [zeroblob] SQL function may be used to create a 5959** zero-filled blob to read or write using the incremental-blob interface. 5960** 5961** To avoid a resource leak, every open [BLOB handle] should eventually 5962** be released by a call to [sqlite3_blob_close()]. 5963*/ 5964int sqlite3_blob_open( 5965 sqlite3*, 5966 const char *zDb, 5967 const char *zTable, 5968 const char *zColumn, 5969 sqlite3_int64 iRow, 5970 int flags, 5971 sqlite3_blob **ppBlob 5972); 5973 5974/* 5975** CAPI3REF: Move a BLOB Handle to a New Row 5976** METHOD: sqlite3_blob 5977** 5978** ^This function is used to move an existing blob handle so that it points 5979** to a different row of the same database table. ^The new row is identified 5980** by the rowid value passed as the second argument. Only the row can be 5981** changed. ^The database, table and column on which the blob handle is open 5982** remain the same. Moving an existing blob handle to a new row can be 5983** faster than closing the existing handle and opening a new one. 5984** 5985** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5986** it must exist and there must be either a blob or text value stored in 5987** the nominated column.)^ ^If the new row is not present in the table, or if 5988** it does not contain a blob or text value, or if another error occurs, an 5989** SQLite error code is returned and the blob handle is considered aborted. 5990** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5991** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5992** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5993** always returns zero. 5994** 5995** ^This function sets the database handle error code and message. 5996*/ 5997int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5998 5999/* 6000** CAPI3REF: Close A BLOB Handle 6001** DESTRUCTOR: sqlite3_blob 6002** 6003** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6004** unconditionally. Even if this routine returns an error code, the 6005** handle is still closed.)^ 6006** 6007** ^If the blob handle being closed was opened for read-write access, and if 6008** the database is in auto-commit mode and there are no other open read-write 6009** blob handles or active write statements, the current transaction is 6010** committed. ^If an error occurs while committing the transaction, an error 6011** code is returned and the transaction rolled back. 6012** 6013** Calling this function with an argument that is not a NULL pointer or an 6014** open blob handle results in undefined behaviour. ^Calling this routine 6015** with a null pointer (such as would be returned by a failed call to 6016** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6017** is passed a valid open blob handle, the values returned by the 6018** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6019*/ 6020int sqlite3_blob_close(sqlite3_blob *); 6021 6022/* 6023** CAPI3REF: Return The Size Of An Open BLOB 6024** METHOD: sqlite3_blob 6025** 6026** ^Returns the size in bytes of the BLOB accessible via the 6027** successfully opened [BLOB handle] in its only argument. ^The 6028** incremental blob I/O routines can only read or overwriting existing 6029** blob content; they cannot change the size of a blob. 6030** 6031** This routine only works on a [BLOB handle] which has been created 6032** by a prior successful call to [sqlite3_blob_open()] and which has not 6033** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6034** to this routine results in undefined and probably undesirable behavior. 6035*/ 6036int sqlite3_blob_bytes(sqlite3_blob *); 6037 6038/* 6039** CAPI3REF: Read Data From A BLOB Incrementally 6040** METHOD: sqlite3_blob 6041** 6042** ^(This function is used to read data from an open [BLOB handle] into a 6043** caller-supplied buffer. N bytes of data are copied into buffer Z 6044** from the open BLOB, starting at offset iOffset.)^ 6045** 6046** ^If offset iOffset is less than N bytes from the end of the BLOB, 6047** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6048** less than zero, [SQLITE_ERROR] is returned and no data is read. 6049** ^The size of the blob (and hence the maximum value of N+iOffset) 6050** can be determined using the [sqlite3_blob_bytes()] interface. 6051** 6052** ^An attempt to read from an expired [BLOB handle] fails with an 6053** error code of [SQLITE_ABORT]. 6054** 6055** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6056** Otherwise, an [error code] or an [extended error code] is returned.)^ 6057** 6058** This routine only works on a [BLOB handle] which has been created 6059** by a prior successful call to [sqlite3_blob_open()] and which has not 6060** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6061** to this routine results in undefined and probably undesirable behavior. 6062** 6063** See also: [sqlite3_blob_write()]. 6064*/ 6065int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6066 6067/* 6068** CAPI3REF: Write Data Into A BLOB Incrementally 6069** METHOD: sqlite3_blob 6070** 6071** ^(This function is used to write data into an open [BLOB handle] from a 6072** caller-supplied buffer. N bytes of data are copied from the buffer Z 6073** into the open BLOB, starting at offset iOffset.)^ 6074** 6075** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6076** Otherwise, an [error code] or an [extended error code] is returned.)^ 6077** ^Unless SQLITE_MISUSE is returned, this function sets the 6078** [database connection] error code and message accessible via 6079** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6080** 6081** ^If the [BLOB handle] passed as the first argument was not opened for 6082** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6083** this function returns [SQLITE_READONLY]. 6084** 6085** This function may only modify the contents of the BLOB; it is 6086** not possible to increase the size of a BLOB using this API. 6087** ^If offset iOffset is less than N bytes from the end of the BLOB, 6088** [SQLITE_ERROR] is returned and no data is written. The size of the 6089** BLOB (and hence the maximum value of N+iOffset) can be determined 6090** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6091** than zero [SQLITE_ERROR] is returned and no data is written. 6092** 6093** ^An attempt to write to an expired [BLOB handle] fails with an 6094** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6095** before the [BLOB handle] expired are not rolled back by the 6096** expiration of the handle, though of course those changes might 6097** have been overwritten by the statement that expired the BLOB handle 6098** or by other independent statements. 6099** 6100** This routine only works on a [BLOB handle] which has been created 6101** by a prior successful call to [sqlite3_blob_open()] and which has not 6102** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6103** to this routine results in undefined and probably undesirable behavior. 6104** 6105** See also: [sqlite3_blob_read()]. 6106*/ 6107int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6108 6109/* 6110** CAPI3REF: Virtual File System Objects 6111** 6112** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6113** that SQLite uses to interact 6114** with the underlying operating system. Most SQLite builds come with a 6115** single default VFS that is appropriate for the host computer. 6116** New VFSes can be registered and existing VFSes can be unregistered. 6117** The following interfaces are provided. 6118** 6119** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6120** ^Names are case sensitive. 6121** ^Names are zero-terminated UTF-8 strings. 6122** ^If there is no match, a NULL pointer is returned. 6123** ^If zVfsName is NULL then the default VFS is returned. 6124** 6125** ^New VFSes are registered with sqlite3_vfs_register(). 6126** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6127** ^The same VFS can be registered multiple times without injury. 6128** ^To make an existing VFS into the default VFS, register it again 6129** with the makeDflt flag set. If two different VFSes with the 6130** same name are registered, the behavior is undefined. If a 6131** VFS is registered with a name that is NULL or an empty string, 6132** then the behavior is undefined. 6133** 6134** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6135** ^(If the default VFS is unregistered, another VFS is chosen as 6136** the default. The choice for the new VFS is arbitrary.)^ 6137*/ 6138sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6139int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6140int sqlite3_vfs_unregister(sqlite3_vfs*); 6141 6142/* 6143** CAPI3REF: Mutexes 6144** 6145** The SQLite core uses these routines for thread 6146** synchronization. Though they are intended for internal 6147** use by SQLite, code that links against SQLite is 6148** permitted to use any of these routines. 6149** 6150** The SQLite source code contains multiple implementations 6151** of these mutex routines. An appropriate implementation 6152** is selected automatically at compile-time. The following 6153** implementations are available in the SQLite core: 6154** 6155** <ul> 6156** <li> SQLITE_MUTEX_PTHREADS 6157** <li> SQLITE_MUTEX_W32 6158** <li> SQLITE_MUTEX_NOOP 6159** </ul> 6160** 6161** The SQLITE_MUTEX_NOOP implementation is a set of routines 6162** that does no real locking and is appropriate for use in 6163** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6164** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6165** and Windows. 6166** 6167** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6168** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6169** implementation is included with the library. In this case the 6170** application must supply a custom mutex implementation using the 6171** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6172** before calling sqlite3_initialize() or any other public sqlite3_ 6173** function that calls sqlite3_initialize(). 6174** 6175** ^The sqlite3_mutex_alloc() routine allocates a new 6176** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6177** routine returns NULL if it is unable to allocate the requested 6178** mutex. The argument to sqlite3_mutex_alloc() must one of these 6179** integer constants: 6180** 6181** <ul> 6182** <li> SQLITE_MUTEX_FAST 6183** <li> SQLITE_MUTEX_RECURSIVE 6184** <li> SQLITE_MUTEX_STATIC_MASTER 6185** <li> SQLITE_MUTEX_STATIC_MEM 6186** <li> SQLITE_MUTEX_STATIC_OPEN 6187** <li> SQLITE_MUTEX_STATIC_PRNG 6188** <li> SQLITE_MUTEX_STATIC_LRU 6189** <li> SQLITE_MUTEX_STATIC_PMEM 6190** <li> SQLITE_MUTEX_STATIC_APP1 6191** <li> SQLITE_MUTEX_STATIC_APP2 6192** <li> SQLITE_MUTEX_STATIC_APP3 6193** <li> SQLITE_MUTEX_STATIC_VFS1 6194** <li> SQLITE_MUTEX_STATIC_VFS2 6195** <li> SQLITE_MUTEX_STATIC_VFS3 6196** </ul> 6197** 6198** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6199** cause sqlite3_mutex_alloc() to create 6200** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6201** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6202** The mutex implementation does not need to make a distinction 6203** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6204** not want to. SQLite will only request a recursive mutex in 6205** cases where it really needs one. If a faster non-recursive mutex 6206** implementation is available on the host platform, the mutex subsystem 6207** might return such a mutex in response to SQLITE_MUTEX_FAST. 6208** 6209** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6210** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6211** a pointer to a static preexisting mutex. ^Nine static mutexes are 6212** used by the current version of SQLite. Future versions of SQLite 6213** may add additional static mutexes. Static mutexes are for internal 6214** use by SQLite only. Applications that use SQLite mutexes should 6215** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6216** SQLITE_MUTEX_RECURSIVE. 6217** 6218** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6219** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6220** returns a different mutex on every call. ^For the static 6221** mutex types, the same mutex is returned on every call that has 6222** the same type number. 6223** 6224** ^The sqlite3_mutex_free() routine deallocates a previously 6225** allocated dynamic mutex. Attempting to deallocate a static 6226** mutex results in undefined behavior. 6227** 6228** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6229** to enter a mutex. ^If another thread is already within the mutex, 6230** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6231** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6232** upon successful entry. ^(Mutexes created using 6233** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6234** In such cases, the 6235** mutex must be exited an equal number of times before another thread 6236** can enter.)^ If the same thread tries to enter any mutex other 6237** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6238** 6239** ^(Some systems (for example, Windows 95) do not support the operation 6240** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6241** will always return SQLITE_BUSY. The SQLite core only ever uses 6242** sqlite3_mutex_try() as an optimization so this is acceptable 6243** behavior.)^ 6244** 6245** ^The sqlite3_mutex_leave() routine exits a mutex that was 6246** previously entered by the same thread. The behavior 6247** is undefined if the mutex is not currently entered by the 6248** calling thread or is not currently allocated. 6249** 6250** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6251** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6252** behave as no-ops. 6253** 6254** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6255*/ 6256sqlite3_mutex *sqlite3_mutex_alloc(int); 6257void sqlite3_mutex_free(sqlite3_mutex*); 6258void sqlite3_mutex_enter(sqlite3_mutex*); 6259int sqlite3_mutex_try(sqlite3_mutex*); 6260void sqlite3_mutex_leave(sqlite3_mutex*); 6261 6262/* 6263** CAPI3REF: Mutex Methods Object 6264** 6265** An instance of this structure defines the low-level routines 6266** used to allocate and use mutexes. 6267** 6268** Usually, the default mutex implementations provided by SQLite are 6269** sufficient, however the application has the option of substituting a custom 6270** implementation for specialized deployments or systems for which SQLite 6271** does not provide a suitable implementation. In this case, the application 6272** creates and populates an instance of this structure to pass 6273** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6274** Additionally, an instance of this structure can be used as an 6275** output variable when querying the system for the current mutex 6276** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6277** 6278** ^The xMutexInit method defined by this structure is invoked as 6279** part of system initialization by the sqlite3_initialize() function. 6280** ^The xMutexInit routine is called by SQLite exactly once for each 6281** effective call to [sqlite3_initialize()]. 6282** 6283** ^The xMutexEnd method defined by this structure is invoked as 6284** part of system shutdown by the sqlite3_shutdown() function. The 6285** implementation of this method is expected to release all outstanding 6286** resources obtained by the mutex methods implementation, especially 6287** those obtained by the xMutexInit method. ^The xMutexEnd() 6288** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6289** 6290** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6291** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6292** xMutexNotheld) implement the following interfaces (respectively): 6293** 6294** <ul> 6295** <li> [sqlite3_mutex_alloc()] </li> 6296** <li> [sqlite3_mutex_free()] </li> 6297** <li> [sqlite3_mutex_enter()] </li> 6298** <li> [sqlite3_mutex_try()] </li> 6299** <li> [sqlite3_mutex_leave()] </li> 6300** <li> [sqlite3_mutex_held()] </li> 6301** <li> [sqlite3_mutex_notheld()] </li> 6302** </ul>)^ 6303** 6304** The only difference is that the public sqlite3_XXX functions enumerated 6305** above silently ignore any invocations that pass a NULL pointer instead 6306** of a valid mutex handle. The implementations of the methods defined 6307** by this structure are not required to handle this case, the results 6308** of passing a NULL pointer instead of a valid mutex handle are undefined 6309** (i.e. it is acceptable to provide an implementation that segfaults if 6310** it is passed a NULL pointer). 6311** 6312** The xMutexInit() method must be threadsafe. It must be harmless to 6313** invoke xMutexInit() multiple times within the same process and without 6314** intervening calls to xMutexEnd(). Second and subsequent calls to 6315** xMutexInit() must be no-ops. 6316** 6317** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6318** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6319** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6320** memory allocation for a fast or recursive mutex. 6321** 6322** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6323** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6324** If xMutexInit fails in any way, it is expected to clean up after itself 6325** prior to returning. 6326*/ 6327typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6328struct sqlite3_mutex_methods { 6329 int (*xMutexInit)(void); 6330 int (*xMutexEnd)(void); 6331 sqlite3_mutex *(*xMutexAlloc)(int); 6332 void (*xMutexFree)(sqlite3_mutex *); 6333 void (*xMutexEnter)(sqlite3_mutex *); 6334 int (*xMutexTry)(sqlite3_mutex *); 6335 void (*xMutexLeave)(sqlite3_mutex *); 6336 int (*xMutexHeld)(sqlite3_mutex *); 6337 int (*xMutexNotheld)(sqlite3_mutex *); 6338}; 6339 6340/* 6341** CAPI3REF: Mutex Verification Routines 6342** 6343** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6344** are intended for use inside assert() statements. The SQLite core 6345** never uses these routines except inside an assert() and applications 6346** are advised to follow the lead of the core. The SQLite core only 6347** provides implementations for these routines when it is compiled 6348** with the SQLITE_DEBUG flag. External mutex implementations 6349** are only required to provide these routines if SQLITE_DEBUG is 6350** defined and if NDEBUG is not defined. 6351** 6352** These routines should return true if the mutex in their argument 6353** is held or not held, respectively, by the calling thread. 6354** 6355** The implementation is not required to provide versions of these 6356** routines that actually work. If the implementation does not provide working 6357** versions of these routines, it should at least provide stubs that always 6358** return true so that one does not get spurious assertion failures. 6359** 6360** If the argument to sqlite3_mutex_held() is a NULL pointer then 6361** the routine should return 1. This seems counter-intuitive since 6362** clearly the mutex cannot be held if it does not exist. But 6363** the reason the mutex does not exist is because the build is not 6364** using mutexes. And we do not want the assert() containing the 6365** call to sqlite3_mutex_held() to fail, so a non-zero return is 6366** the appropriate thing to do. The sqlite3_mutex_notheld() 6367** interface should also return 1 when given a NULL pointer. 6368*/ 6369#ifndef NDEBUG 6370int sqlite3_mutex_held(sqlite3_mutex*); 6371int sqlite3_mutex_notheld(sqlite3_mutex*); 6372#endif 6373 6374/* 6375** CAPI3REF: Mutex Types 6376** 6377** The [sqlite3_mutex_alloc()] interface takes a single argument 6378** which is one of these integer constants. 6379** 6380** The set of static mutexes may change from one SQLite release to the 6381** next. Applications that override the built-in mutex logic must be 6382** prepared to accommodate additional static mutexes. 6383*/ 6384#define SQLITE_MUTEX_FAST 0 6385#define SQLITE_MUTEX_RECURSIVE 1 6386#define SQLITE_MUTEX_STATIC_MASTER 2 6387#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6388#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6389#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6390#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 6391#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6392#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6393#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6394#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6395#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6396#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6397#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6398#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6399#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6400 6401/* 6402** CAPI3REF: Retrieve the mutex for a database connection 6403** METHOD: sqlite3 6404** 6405** ^This interface returns a pointer the [sqlite3_mutex] object that 6406** serializes access to the [database connection] given in the argument 6407** when the [threading mode] is Serialized. 6408** ^If the [threading mode] is Single-thread or Multi-thread then this 6409** routine returns a NULL pointer. 6410*/ 6411sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6412 6413/* 6414** CAPI3REF: Low-Level Control Of Database Files 6415** METHOD: sqlite3 6416** 6417** ^The [sqlite3_file_control()] interface makes a direct call to the 6418** xFileControl method for the [sqlite3_io_methods] object associated 6419** with a particular database identified by the second argument. ^The 6420** name of the database is "main" for the main database or "temp" for the 6421** TEMP database, or the name that appears after the AS keyword for 6422** databases that are added using the [ATTACH] SQL command. 6423** ^A NULL pointer can be used in place of "main" to refer to the 6424** main database file. 6425** ^The third and fourth parameters to this routine 6426** are passed directly through to the second and third parameters of 6427** the xFileControl method. ^The return value of the xFileControl 6428** method becomes the return value of this routine. 6429** 6430** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6431** a pointer to the underlying [sqlite3_file] object to be written into 6432** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6433** case is a short-circuit path which does not actually invoke the 6434** underlying sqlite3_io_methods.xFileControl method. 6435** 6436** ^If the second parameter (zDbName) does not match the name of any 6437** open database file, then SQLITE_ERROR is returned. ^This error 6438** code is not remembered and will not be recalled by [sqlite3_errcode()] 6439** or [sqlite3_errmsg()]. The underlying xFileControl method might 6440** also return SQLITE_ERROR. There is no way to distinguish between 6441** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6442** xFileControl method. 6443** 6444** See also: [SQLITE_FCNTL_LOCKSTATE] 6445*/ 6446int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6447 6448/* 6449** CAPI3REF: Testing Interface 6450** 6451** ^The sqlite3_test_control() interface is used to read out internal 6452** state of SQLite and to inject faults into SQLite for testing 6453** purposes. ^The first parameter is an operation code that determines 6454** the number, meaning, and operation of all subsequent parameters. 6455** 6456** This interface is not for use by applications. It exists solely 6457** for verifying the correct operation of the SQLite library. Depending 6458** on how the SQLite library is compiled, this interface might not exist. 6459** 6460** The details of the operation codes, their meanings, the parameters 6461** they take, and what they do are all subject to change without notice. 6462** Unlike most of the SQLite API, this function is not guaranteed to 6463** operate consistently from one release to the next. 6464*/ 6465int sqlite3_test_control(int op, ...); 6466 6467/* 6468** CAPI3REF: Testing Interface Operation Codes 6469** 6470** These constants are the valid operation code parameters used 6471** as the first argument to [sqlite3_test_control()]. 6472** 6473** These parameters and their meanings are subject to change 6474** without notice. These values are for testing purposes only. 6475** Applications should not use any of these parameters or the 6476** [sqlite3_test_control()] interface. 6477*/ 6478#define SQLITE_TESTCTRL_FIRST 5 6479#define SQLITE_TESTCTRL_PRNG_SAVE 5 6480#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6481#define SQLITE_TESTCTRL_PRNG_RESET 7 6482#define SQLITE_TESTCTRL_BITVEC_TEST 8 6483#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6484#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6485#define SQLITE_TESTCTRL_PENDING_BYTE 11 6486#define SQLITE_TESTCTRL_ASSERT 12 6487#define SQLITE_TESTCTRL_ALWAYS 13 6488#define SQLITE_TESTCTRL_RESERVE 14 6489#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6490#define SQLITE_TESTCTRL_ISKEYWORD 16 6491#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6492#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6493#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6494#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6495#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6496#define SQLITE_TESTCTRL_BYTEORDER 22 6497#define SQLITE_TESTCTRL_ISINIT 23 6498#define SQLITE_TESTCTRL_SORTER_MMAP 24 6499#define SQLITE_TESTCTRL_IMPOSTER 25 6500#define SQLITE_TESTCTRL_LAST 25 6501 6502/* 6503** CAPI3REF: SQLite Runtime Status 6504** 6505** ^These interfaces are used to retrieve runtime status information 6506** about the performance of SQLite, and optionally to reset various 6507** highwater marks. ^The first argument is an integer code for 6508** the specific parameter to measure. ^(Recognized integer codes 6509** are of the form [status parameters | SQLITE_STATUS_...].)^ 6510** ^The current value of the parameter is returned into *pCurrent. 6511** ^The highest recorded value is returned in *pHighwater. ^If the 6512** resetFlag is true, then the highest record value is reset after 6513** *pHighwater is written. ^(Some parameters do not record the highest 6514** value. For those parameters 6515** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6516** ^(Other parameters record only the highwater mark and not the current 6517** value. For these latter parameters nothing is written into *pCurrent.)^ 6518** 6519** ^The sqlite3_status() and sqlite3_status64() routines return 6520** SQLITE_OK on success and a non-zero [error code] on failure. 6521** 6522** If either the current value or the highwater mark is too large to 6523** be represented by a 32-bit integer, then the values returned by 6524** sqlite3_status() are undefined. 6525** 6526** See also: [sqlite3_db_status()] 6527*/ 6528int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6529int sqlite3_status64( 6530 int op, 6531 sqlite3_int64 *pCurrent, 6532 sqlite3_int64 *pHighwater, 6533 int resetFlag 6534); 6535 6536 6537/* 6538** CAPI3REF: Status Parameters 6539** KEYWORDS: {status parameters} 6540** 6541** These integer constants designate various run-time status parameters 6542** that can be returned by [sqlite3_status()]. 6543** 6544** <dl> 6545** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6546** <dd>This parameter is the current amount of memory checked out 6547** using [sqlite3_malloc()], either directly or indirectly. The 6548** figure includes calls made to [sqlite3_malloc()] by the application 6549** and internal memory usage by the SQLite library. Scratch memory 6550** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6551** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6552** this parameter. The amount returned is the sum of the allocation 6553** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6554** 6555** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6556** <dd>This parameter records the largest memory allocation request 6557** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6558** internal equivalents). Only the value returned in the 6559** *pHighwater parameter to [sqlite3_status()] is of interest. 6560** The value written into the *pCurrent parameter is undefined.</dd>)^ 6561** 6562** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6563** <dd>This parameter records the number of separate memory allocations 6564** currently checked out.</dd>)^ 6565** 6566** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6567** <dd>This parameter returns the number of pages used out of the 6568** [pagecache memory allocator] that was configured using 6569** [SQLITE_CONFIG_PAGECACHE]. The 6570** value returned is in pages, not in bytes.</dd>)^ 6571** 6572** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6573** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6574** <dd>This parameter returns the number of bytes of page cache 6575** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6576** buffer and where forced to overflow to [sqlite3_malloc()]. The 6577** returned value includes allocations that overflowed because they 6578** where too large (they were larger than the "sz" parameter to 6579** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6580** no space was left in the page cache.</dd>)^ 6581** 6582** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6583** <dd>This parameter records the largest memory allocation request 6584** handed to [pagecache memory allocator]. Only the value returned in the 6585** *pHighwater parameter to [sqlite3_status()] is of interest. 6586** The value written into the *pCurrent parameter is undefined.</dd>)^ 6587** 6588** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6589** <dd>This parameter returns the number of allocations used out of the 6590** [scratch memory allocator] configured using 6591** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6592** in bytes. Since a single thread may only have one scratch allocation 6593** outstanding at time, this parameter also reports the number of threads 6594** using scratch memory at the same time.</dd>)^ 6595** 6596** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6597** <dd>This parameter returns the number of bytes of scratch memory 6598** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6599** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6600** returned include overflows because the requested allocation was too 6601** larger (that is, because the requested allocation was larger than the 6602** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6603** slots were available. 6604** </dd>)^ 6605** 6606** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6607** <dd>This parameter records the largest memory allocation request 6608** handed to [scratch memory allocator]. Only the value returned in the 6609** *pHighwater parameter to [sqlite3_status()] is of interest. 6610** The value written into the *pCurrent parameter is undefined.</dd>)^ 6611** 6612** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6613** <dd>The *pHighwater parameter records the deepest parser stack. 6614** The *pCurrent value is undefined. The *pHighwater value is only 6615** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6616** </dl> 6617** 6618** New status parameters may be added from time to time. 6619*/ 6620#define SQLITE_STATUS_MEMORY_USED 0 6621#define SQLITE_STATUS_PAGECACHE_USED 1 6622#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6623#define SQLITE_STATUS_SCRATCH_USED 3 6624#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6625#define SQLITE_STATUS_MALLOC_SIZE 5 6626#define SQLITE_STATUS_PARSER_STACK 6 6627#define SQLITE_STATUS_PAGECACHE_SIZE 7 6628#define SQLITE_STATUS_SCRATCH_SIZE 8 6629#define SQLITE_STATUS_MALLOC_COUNT 9 6630 6631/* 6632** CAPI3REF: Database Connection Status 6633** METHOD: sqlite3 6634** 6635** ^This interface is used to retrieve runtime status information 6636** about a single [database connection]. ^The first argument is the 6637** database connection object to be interrogated. ^The second argument 6638** is an integer constant, taken from the set of 6639** [SQLITE_DBSTATUS options], that 6640** determines the parameter to interrogate. The set of 6641** [SQLITE_DBSTATUS options] is likely 6642** to grow in future releases of SQLite. 6643** 6644** ^The current value of the requested parameter is written into *pCur 6645** and the highest instantaneous value is written into *pHiwtr. ^If 6646** the resetFlg is true, then the highest instantaneous value is 6647** reset back down to the current value. 6648** 6649** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6650** non-zero [error code] on failure. 6651** 6652** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6653*/ 6654int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6655 6656/* 6657** CAPI3REF: Status Parameters for database connections 6658** KEYWORDS: {SQLITE_DBSTATUS options} 6659** 6660** These constants are the available integer "verbs" that can be passed as 6661** the second argument to the [sqlite3_db_status()] interface. 6662** 6663** New verbs may be added in future releases of SQLite. Existing verbs 6664** might be discontinued. Applications should check the return code from 6665** [sqlite3_db_status()] to make sure that the call worked. 6666** The [sqlite3_db_status()] interface will return a non-zero error code 6667** if a discontinued or unsupported verb is invoked. 6668** 6669** <dl> 6670** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6671** <dd>This parameter returns the number of lookaside memory slots currently 6672** checked out.</dd>)^ 6673** 6674** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6675** <dd>This parameter returns the number malloc attempts that were 6676** satisfied using lookaside memory. Only the high-water value is meaningful; 6677** the current value is always zero.)^ 6678** 6679** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6680** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6681** <dd>This parameter returns the number malloc attempts that might have 6682** been satisfied using lookaside memory but failed due to the amount of 6683** memory requested being larger than the lookaside slot size. 6684** Only the high-water value is meaningful; 6685** the current value is always zero.)^ 6686** 6687** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6688** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6689** <dd>This parameter returns the number malloc attempts that might have 6690** been satisfied using lookaside memory but failed due to all lookaside 6691** memory already being in use. 6692** Only the high-water value is meaningful; 6693** the current value is always zero.)^ 6694** 6695** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6696** <dd>This parameter returns the approximate number of bytes of heap 6697** memory used by all pager caches associated with the database connection.)^ 6698** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6699** 6700** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6701** <dd>This parameter returns the approximate number of bytes of heap 6702** memory used to store the schema for all databases associated 6703** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6704** ^The full amount of memory used by the schemas is reported, even if the 6705** schema memory is shared with other database connections due to 6706** [shared cache mode] being enabled. 6707** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6708** 6709** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6710** <dd>This parameter returns the approximate number of bytes of heap 6711** and lookaside memory used by all prepared statements associated with 6712** the database connection.)^ 6713** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6714** </dd> 6715** 6716** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6717** <dd>This parameter returns the number of pager cache hits that have 6718** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6719** is always 0. 6720** </dd> 6721** 6722** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6723** <dd>This parameter returns the number of pager cache misses that have 6724** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6725** is always 0. 6726** </dd> 6727** 6728** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6729** <dd>This parameter returns the number of dirty cache entries that have 6730** been written to disk. Specifically, the number of pages written to the 6731** wal file in wal mode databases, or the number of pages written to the 6732** database file in rollback mode databases. Any pages written as part of 6733** transaction rollback or database recovery operations are not included. 6734** If an IO or other error occurs while writing a page to disk, the effect 6735** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6736** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6737** </dd> 6738** 6739** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 6740** <dd>This parameter returns zero for the current value if and only if 6741** all foreign key constraints (deferred or immediate) have been 6742** resolved.)^ ^The highwater mark is always 0. 6743** </dd> 6744** </dl> 6745*/ 6746#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6747#define SQLITE_DBSTATUS_CACHE_USED 1 6748#define SQLITE_DBSTATUS_SCHEMA_USED 2 6749#define SQLITE_DBSTATUS_STMT_USED 3 6750#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6751#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6752#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6753#define SQLITE_DBSTATUS_CACHE_HIT 7 6754#define SQLITE_DBSTATUS_CACHE_MISS 8 6755#define SQLITE_DBSTATUS_CACHE_WRITE 9 6756#define SQLITE_DBSTATUS_DEFERRED_FKS 10 6757#define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */ 6758 6759 6760/* 6761** CAPI3REF: Prepared Statement Status 6762** METHOD: sqlite3_stmt 6763** 6764** ^(Each prepared statement maintains various 6765** [SQLITE_STMTSTATUS counters] that measure the number 6766** of times it has performed specific operations.)^ These counters can 6767** be used to monitor the performance characteristics of the prepared 6768** statements. For example, if the number of table steps greatly exceeds 6769** the number of table searches or result rows, that would tend to indicate 6770** that the prepared statement is using a full table scan rather than 6771** an index. 6772** 6773** ^(This interface is used to retrieve and reset counter values from 6774** a [prepared statement]. The first argument is the prepared statement 6775** object to be interrogated. The second argument 6776** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6777** to be interrogated.)^ 6778** ^The current value of the requested counter is returned. 6779** ^If the resetFlg is true, then the counter is reset to zero after this 6780** interface call returns. 6781** 6782** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6783*/ 6784int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6785 6786/* 6787** CAPI3REF: Status Parameters for prepared statements 6788** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6789** 6790** These preprocessor macros define integer codes that name counter 6791** values associated with the [sqlite3_stmt_status()] interface. 6792** The meanings of the various counters are as follows: 6793** 6794** <dl> 6795** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6796** <dd>^This is the number of times that SQLite has stepped forward in 6797** a table as part of a full table scan. Large numbers for this counter 6798** may indicate opportunities for performance improvement through 6799** careful use of indices.</dd> 6800** 6801** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6802** <dd>^This is the number of sort operations that have occurred. 6803** A non-zero value in this counter may indicate an opportunity to 6804** improvement performance through careful use of indices.</dd> 6805** 6806** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6807** <dd>^This is the number of rows inserted into transient indices that 6808** were created automatically in order to help joins run faster. 6809** A non-zero value in this counter may indicate an opportunity to 6810** improvement performance by adding permanent indices that do not 6811** need to be reinitialized each time the statement is run.</dd> 6812** 6813** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 6814** <dd>^This is the number of virtual machine operations executed 6815** by the prepared statement if that number is less than or equal 6816** to 2147483647. The number of virtual machine operations can be 6817** used as a proxy for the total work done by the prepared statement. 6818** If the number of virtual machine operations exceeds 2147483647 6819** then the value returned by this statement status code is undefined. 6820** </dd> 6821** </dl> 6822*/ 6823#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6824#define SQLITE_STMTSTATUS_SORT 2 6825#define SQLITE_STMTSTATUS_AUTOINDEX 3 6826#define SQLITE_STMTSTATUS_VM_STEP 4 6827 6828/* 6829** CAPI3REF: Custom Page Cache Object 6830** 6831** The sqlite3_pcache type is opaque. It is implemented by 6832** the pluggable module. The SQLite core has no knowledge of 6833** its size or internal structure and never deals with the 6834** sqlite3_pcache object except by holding and passing pointers 6835** to the object. 6836** 6837** See [sqlite3_pcache_methods2] for additional information. 6838*/ 6839typedef struct sqlite3_pcache sqlite3_pcache; 6840 6841/* 6842** CAPI3REF: Custom Page Cache Object 6843** 6844** The sqlite3_pcache_page object represents a single page in the 6845** page cache. The page cache will allocate instances of this 6846** object. Various methods of the page cache use pointers to instances 6847** of this object as parameters or as their return value. 6848** 6849** See [sqlite3_pcache_methods2] for additional information. 6850*/ 6851typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6852struct sqlite3_pcache_page { 6853 void *pBuf; /* The content of the page */ 6854 void *pExtra; /* Extra information associated with the page */ 6855}; 6856 6857/* 6858** CAPI3REF: Application Defined Page Cache. 6859** KEYWORDS: {page cache} 6860** 6861** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6862** register an alternative page cache implementation by passing in an 6863** instance of the sqlite3_pcache_methods2 structure.)^ 6864** In many applications, most of the heap memory allocated by 6865** SQLite is used for the page cache. 6866** By implementing a 6867** custom page cache using this API, an application can better control 6868** the amount of memory consumed by SQLite, the way in which 6869** that memory is allocated and released, and the policies used to 6870** determine exactly which parts of a database file are cached and for 6871** how long. 6872** 6873** The alternative page cache mechanism is an 6874** extreme measure that is only needed by the most demanding applications. 6875** The built-in page cache is recommended for most uses. 6876** 6877** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6878** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6879** the application may discard the parameter after the call to 6880** [sqlite3_config()] returns.)^ 6881** 6882** [[the xInit() page cache method]] 6883** ^(The xInit() method is called once for each effective 6884** call to [sqlite3_initialize()])^ 6885** (usually only once during the lifetime of the process). ^(The xInit() 6886** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6887** The intent of the xInit() method is to set up global data structures 6888** required by the custom page cache implementation. 6889** ^(If the xInit() method is NULL, then the 6890** built-in default page cache is used instead of the application defined 6891** page cache.)^ 6892** 6893** [[the xShutdown() page cache method]] 6894** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6895** It can be used to clean up 6896** any outstanding resources before process shutdown, if required. 6897** ^The xShutdown() method may be NULL. 6898** 6899** ^SQLite automatically serializes calls to the xInit method, 6900** so the xInit method need not be threadsafe. ^The 6901** xShutdown method is only called from [sqlite3_shutdown()] so it does 6902** not need to be threadsafe either. All other methods must be threadsafe 6903** in multithreaded applications. 6904** 6905** ^SQLite will never invoke xInit() more than once without an intervening 6906** call to xShutdown(). 6907** 6908** [[the xCreate() page cache methods]] 6909** ^SQLite invokes the xCreate() method to construct a new cache instance. 6910** SQLite will typically create one cache instance for each open database file, 6911** though this is not guaranteed. ^The 6912** first parameter, szPage, is the size in bytes of the pages that must 6913** be allocated by the cache. ^szPage will always a power of two. ^The 6914** second parameter szExtra is a number of bytes of extra storage 6915** associated with each page cache entry. ^The szExtra parameter will 6916** a number less than 250. SQLite will use the 6917** extra szExtra bytes on each page to store metadata about the underlying 6918** database page on disk. The value passed into szExtra depends 6919** on the SQLite version, the target platform, and how SQLite was compiled. 6920** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6921** created will be used to cache database pages of a file stored on disk, or 6922** false if it is used for an in-memory database. The cache implementation 6923** does not have to do anything special based with the value of bPurgeable; 6924** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6925** never invoke xUnpin() except to deliberately delete a page. 6926** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6927** false will always have the "discard" flag set to true. 6928** ^Hence, a cache created with bPurgeable false will 6929** never contain any unpinned pages. 6930** 6931** [[the xCachesize() page cache method]] 6932** ^(The xCachesize() method may be called at any time by SQLite to set the 6933** suggested maximum cache-size (number of pages stored by) the cache 6934** instance passed as the first argument. This is the value configured using 6935** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6936** parameter, the implementation is not required to do anything with this 6937** value; it is advisory only. 6938** 6939** [[the xPagecount() page cache methods]] 6940** The xPagecount() method must return the number of pages currently 6941** stored in the cache, both pinned and unpinned. 6942** 6943** [[the xFetch() page cache methods]] 6944** The xFetch() method locates a page in the cache and returns a pointer to 6945** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6946** The pBuf element of the returned sqlite3_pcache_page object will be a 6947** pointer to a buffer of szPage bytes used to store the content of a 6948** single database page. The pExtra element of sqlite3_pcache_page will be 6949** a pointer to the szExtra bytes of extra storage that SQLite has requested 6950** for each entry in the page cache. 6951** 6952** The page to be fetched is determined by the key. ^The minimum key value 6953** is 1. After it has been retrieved using xFetch, the page is considered 6954** to be "pinned". 6955** 6956** If the requested page is already in the page cache, then the page cache 6957** implementation must return a pointer to the page buffer with its content 6958** intact. If the requested page is not already in the cache, then the 6959** cache implementation should use the value of the createFlag 6960** parameter to help it determined what action to take: 6961** 6962** <table border=1 width=85% align=center> 6963** <tr><th> createFlag <th> Behavior when page is not already in cache 6964** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6965** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6966** Otherwise return NULL. 6967** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6968** NULL if allocating a new page is effectively impossible. 6969** </table> 6970** 6971** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6972** will only use a createFlag of 2 after a prior call with a createFlag of 1 6973** failed.)^ In between the to xFetch() calls, SQLite may 6974** attempt to unpin one or more cache pages by spilling the content of 6975** pinned pages to disk and synching the operating system disk cache. 6976** 6977** [[the xUnpin() page cache method]] 6978** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6979** as its second argument. If the third parameter, discard, is non-zero, 6980** then the page must be evicted from the cache. 6981** ^If the discard parameter is 6982** zero, then the page may be discarded or retained at the discretion of 6983** page cache implementation. ^The page cache implementation 6984** may choose to evict unpinned pages at any time. 6985** 6986** The cache must not perform any reference counting. A single 6987** call to xUnpin() unpins the page regardless of the number of prior calls 6988** to xFetch(). 6989** 6990** [[the xRekey() page cache methods]] 6991** The xRekey() method is used to change the key value associated with the 6992** page passed as the second argument. If the cache 6993** previously contains an entry associated with newKey, it must be 6994** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6995** to be pinned. 6996** 6997** When SQLite calls the xTruncate() method, the cache must discard all 6998** existing cache entries with page numbers (keys) greater than or equal 6999** to the value of the iLimit parameter passed to xTruncate(). If any 7000** of these pages are pinned, they are implicitly unpinned, meaning that 7001** they can be safely discarded. 7002** 7003** [[the xDestroy() page cache method]] 7004** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7005** All resources associated with the specified cache should be freed. ^After 7006** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7007** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7008** functions. 7009** 7010** [[the xShrink() page cache method]] 7011** ^SQLite invokes the xShrink() method when it wants the page cache to 7012** free up as much of heap memory as possible. The page cache implementation 7013** is not obligated to free any memory, but well-behaved implementations should 7014** do their best. 7015*/ 7016typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7017struct sqlite3_pcache_methods2 { 7018 int iVersion; 7019 void *pArg; 7020 int (*xInit)(void*); 7021 void (*xShutdown)(void*); 7022 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7023 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7024 int (*xPagecount)(sqlite3_pcache*); 7025 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7026 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7027 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7028 unsigned oldKey, unsigned newKey); 7029 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7030 void (*xDestroy)(sqlite3_pcache*); 7031 void (*xShrink)(sqlite3_pcache*); 7032}; 7033 7034/* 7035** This is the obsolete pcache_methods object that has now been replaced 7036** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7037** retained in the header file for backwards compatibility only. 7038*/ 7039typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7040struct sqlite3_pcache_methods { 7041 void *pArg; 7042 int (*xInit)(void*); 7043 void (*xShutdown)(void*); 7044 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7045 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7046 int (*xPagecount)(sqlite3_pcache*); 7047 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7048 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7049 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7050 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7051 void (*xDestroy)(sqlite3_pcache*); 7052}; 7053 7054 7055/* 7056** CAPI3REF: Online Backup Object 7057** 7058** The sqlite3_backup object records state information about an ongoing 7059** online backup operation. ^The sqlite3_backup object is created by 7060** a call to [sqlite3_backup_init()] and is destroyed by a call to 7061** [sqlite3_backup_finish()]. 7062** 7063** See Also: [Using the SQLite Online Backup API] 7064*/ 7065typedef struct sqlite3_backup sqlite3_backup; 7066 7067/* 7068** CAPI3REF: Online Backup API. 7069** 7070** The backup API copies the content of one database into another. 7071** It is useful either for creating backups of databases or 7072** for copying in-memory databases to or from persistent files. 7073** 7074** See Also: [Using the SQLite Online Backup API] 7075** 7076** ^SQLite holds a write transaction open on the destination database file 7077** for the duration of the backup operation. 7078** ^The source database is read-locked only while it is being read; 7079** it is not locked continuously for the entire backup operation. 7080** ^Thus, the backup may be performed on a live source database without 7081** preventing other database connections from 7082** reading or writing to the source database while the backup is underway. 7083** 7084** ^(To perform a backup operation: 7085** <ol> 7086** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7087** backup, 7088** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7089** the data between the two databases, and finally 7090** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7091** associated with the backup operation. 7092** </ol>)^ 7093** There should be exactly one call to sqlite3_backup_finish() for each 7094** successful call to sqlite3_backup_init(). 7095** 7096** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7097** 7098** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7099** [database connection] associated with the destination database 7100** and the database name, respectively. 7101** ^The database name is "main" for the main database, "temp" for the 7102** temporary database, or the name specified after the AS keyword in 7103** an [ATTACH] statement for an attached database. 7104** ^The S and M arguments passed to 7105** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7106** and database name of the source database, respectively. 7107** ^The source and destination [database connections] (parameters S and D) 7108** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7109** an error. 7110** 7111** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if 7112** there is already a read or read-write transaction open on the 7113** destination database. 7114** 7115** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7116** returned and an error code and error message are stored in the 7117** destination [database connection] D. 7118** ^The error code and message for the failed call to sqlite3_backup_init() 7119** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7120** [sqlite3_errmsg16()] functions. 7121** ^A successful call to sqlite3_backup_init() returns a pointer to an 7122** [sqlite3_backup] object. 7123** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7124** sqlite3_backup_finish() functions to perform the specified backup 7125** operation. 7126** 7127** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7128** 7129** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7130** the source and destination databases specified by [sqlite3_backup] object B. 7131** ^If N is negative, all remaining source pages are copied. 7132** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7133** are still more pages to be copied, then the function returns [SQLITE_OK]. 7134** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7135** from source to destination, then it returns [SQLITE_DONE]. 7136** ^If an error occurs while running sqlite3_backup_step(B,N), 7137** then an [error code] is returned. ^As well as [SQLITE_OK] and 7138** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7139** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7140** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7141** 7142** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7143** <ol> 7144** <li> the destination database was opened read-only, or 7145** <li> the destination database is using write-ahead-log journaling 7146** and the destination and source page sizes differ, or 7147** <li> the destination database is an in-memory database and the 7148** destination and source page sizes differ. 7149** </ol>)^ 7150** 7151** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7152** the [sqlite3_busy_handler | busy-handler function] 7153** is invoked (if one is specified). ^If the 7154** busy-handler returns non-zero before the lock is available, then 7155** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7156** sqlite3_backup_step() can be retried later. ^If the source 7157** [database connection] 7158** is being used to write to the source database when sqlite3_backup_step() 7159** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7160** case the call to sqlite3_backup_step() can be retried later on. ^(If 7161** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7162** [SQLITE_READONLY] is returned, then 7163** there is no point in retrying the call to sqlite3_backup_step(). These 7164** errors are considered fatal.)^ The application must accept 7165** that the backup operation has failed and pass the backup operation handle 7166** to the sqlite3_backup_finish() to release associated resources. 7167** 7168** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7169** on the destination file. ^The exclusive lock is not released until either 7170** sqlite3_backup_finish() is called or the backup operation is complete 7171** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7172** sqlite3_backup_step() obtains a [shared lock] on the source database that 7173** lasts for the duration of the sqlite3_backup_step() call. 7174** ^Because the source database is not locked between calls to 7175** sqlite3_backup_step(), the source database may be modified mid-way 7176** through the backup process. ^If the source database is modified by an 7177** external process or via a database connection other than the one being 7178** used by the backup operation, then the backup will be automatically 7179** restarted by the next call to sqlite3_backup_step(). ^If the source 7180** database is modified by the using the same database connection as is used 7181** by the backup operation, then the backup database is automatically 7182** updated at the same time. 7183** 7184** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7185** 7186** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7187** application wishes to abandon the backup operation, the application 7188** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7189** ^The sqlite3_backup_finish() interfaces releases all 7190** resources associated with the [sqlite3_backup] object. 7191** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7192** active write-transaction on the destination database is rolled back. 7193** The [sqlite3_backup] object is invalid 7194** and may not be used following a call to sqlite3_backup_finish(). 7195** 7196** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7197** sqlite3_backup_step() errors occurred, regardless or whether or not 7198** sqlite3_backup_step() completed. 7199** ^If an out-of-memory condition or IO error occurred during any prior 7200** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7201** sqlite3_backup_finish() returns the corresponding [error code]. 7202** 7203** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7204** is not a permanent error and does not affect the return value of 7205** sqlite3_backup_finish(). 7206** 7207** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7208** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7209** 7210** ^The sqlite3_backup_remaining() routine returns the number of pages still 7211** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7212** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7213** in the source database at the conclusion of the most recent 7214** sqlite3_backup_step(). 7215** ^(The values returned by these functions are only updated by 7216** sqlite3_backup_step(). If the source database is modified in a way that 7217** changes the size of the source database or the number of pages remaining, 7218** those changes are not reflected in the output of sqlite3_backup_pagecount() 7219** and sqlite3_backup_remaining() until after the next 7220** sqlite3_backup_step().)^ 7221** 7222** <b>Concurrent Usage of Database Handles</b> 7223** 7224** ^The source [database connection] may be used by the application for other 7225** purposes while a backup operation is underway or being initialized. 7226** ^If SQLite is compiled and configured to support threadsafe database 7227** connections, then the source database connection may be used concurrently 7228** from within other threads. 7229** 7230** However, the application must guarantee that the destination 7231** [database connection] is not passed to any other API (by any thread) after 7232** sqlite3_backup_init() is called and before the corresponding call to 7233** sqlite3_backup_finish(). SQLite does not currently check to see 7234** if the application incorrectly accesses the destination [database connection] 7235** and so no error code is reported, but the operations may malfunction 7236** nevertheless. Use of the destination database connection while a 7237** backup is in progress might also also cause a mutex deadlock. 7238** 7239** If running in [shared cache mode], the application must 7240** guarantee that the shared cache used by the destination database 7241** is not accessed while the backup is running. In practice this means 7242** that the application must guarantee that the disk file being 7243** backed up to is not accessed by any connection within the process, 7244** not just the specific connection that was passed to sqlite3_backup_init(). 7245** 7246** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7247** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7248** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7249** APIs are not strictly speaking threadsafe. If they are invoked at the 7250** same time as another thread is invoking sqlite3_backup_step() it is 7251** possible that they return invalid values. 7252*/ 7253sqlite3_backup *sqlite3_backup_init( 7254 sqlite3 *pDest, /* Destination database handle */ 7255 const char *zDestName, /* Destination database name */ 7256 sqlite3 *pSource, /* Source database handle */ 7257 const char *zSourceName /* Source database name */ 7258); 7259int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7260int sqlite3_backup_finish(sqlite3_backup *p); 7261int sqlite3_backup_remaining(sqlite3_backup *p); 7262int sqlite3_backup_pagecount(sqlite3_backup *p); 7263 7264/* 7265** CAPI3REF: Unlock Notification 7266** METHOD: sqlite3 7267** 7268** ^When running in shared-cache mode, a database operation may fail with 7269** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7270** individual tables within the shared-cache cannot be obtained. See 7271** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7272** ^This API may be used to register a callback that SQLite will invoke 7273** when the connection currently holding the required lock relinquishes it. 7274** ^This API is only available if the library was compiled with the 7275** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7276** 7277** See Also: [Using the SQLite Unlock Notification Feature]. 7278** 7279** ^Shared-cache locks are released when a database connection concludes 7280** its current transaction, either by committing it or rolling it back. 7281** 7282** ^When a connection (known as the blocked connection) fails to obtain a 7283** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7284** identity of the database connection (the blocking connection) that 7285** has locked the required resource is stored internally. ^After an 7286** application receives an SQLITE_LOCKED error, it may call the 7287** sqlite3_unlock_notify() method with the blocked connection handle as 7288** the first argument to register for a callback that will be invoked 7289** when the blocking connections current transaction is concluded. ^The 7290** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7291** call that concludes the blocking connections transaction. 7292** 7293** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7294** there is a chance that the blocking connection will have already 7295** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7296** If this happens, then the specified callback is invoked immediately, 7297** from within the call to sqlite3_unlock_notify().)^ 7298** 7299** ^If the blocked connection is attempting to obtain a write-lock on a 7300** shared-cache table, and more than one other connection currently holds 7301** a read-lock on the same table, then SQLite arbitrarily selects one of 7302** the other connections to use as the blocking connection. 7303** 7304** ^(There may be at most one unlock-notify callback registered by a 7305** blocked connection. If sqlite3_unlock_notify() is called when the 7306** blocked connection already has a registered unlock-notify callback, 7307** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7308** called with a NULL pointer as its second argument, then any existing 7309** unlock-notify callback is canceled. ^The blocked connections 7310** unlock-notify callback may also be canceled by closing the blocked 7311** connection using [sqlite3_close()]. 7312** 7313** The unlock-notify callback is not reentrant. If an application invokes 7314** any sqlite3_xxx API functions from within an unlock-notify callback, a 7315** crash or deadlock may be the result. 7316** 7317** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7318** returns SQLITE_OK. 7319** 7320** <b>Callback Invocation Details</b> 7321** 7322** When an unlock-notify callback is registered, the application provides a 7323** single void* pointer that is passed to the callback when it is invoked. 7324** However, the signature of the callback function allows SQLite to pass 7325** it an array of void* context pointers. The first argument passed to 7326** an unlock-notify callback is a pointer to an array of void* pointers, 7327** and the second is the number of entries in the array. 7328** 7329** When a blocking connections transaction is concluded, there may be 7330** more than one blocked connection that has registered for an unlock-notify 7331** callback. ^If two or more such blocked connections have specified the 7332** same callback function, then instead of invoking the callback function 7333** multiple times, it is invoked once with the set of void* context pointers 7334** specified by the blocked connections bundled together into an array. 7335** This gives the application an opportunity to prioritize any actions 7336** related to the set of unblocked database connections. 7337** 7338** <b>Deadlock Detection</b> 7339** 7340** Assuming that after registering for an unlock-notify callback a 7341** database waits for the callback to be issued before taking any further 7342** action (a reasonable assumption), then using this API may cause the 7343** application to deadlock. For example, if connection X is waiting for 7344** connection Y's transaction to be concluded, and similarly connection 7345** Y is waiting on connection X's transaction, then neither connection 7346** will proceed and the system may remain deadlocked indefinitely. 7347** 7348** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7349** detection. ^If a given call to sqlite3_unlock_notify() would put the 7350** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7351** unlock-notify callback is registered. The system is said to be in 7352** a deadlocked state if connection A has registered for an unlock-notify 7353** callback on the conclusion of connection B's transaction, and connection 7354** B has itself registered for an unlock-notify callback when connection 7355** A's transaction is concluded. ^Indirect deadlock is also detected, so 7356** the system is also considered to be deadlocked if connection B has 7357** registered for an unlock-notify callback on the conclusion of connection 7358** C's transaction, where connection C is waiting on connection A. ^Any 7359** number of levels of indirection are allowed. 7360** 7361** <b>The "DROP TABLE" Exception</b> 7362** 7363** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7364** always appropriate to call sqlite3_unlock_notify(). There is however, 7365** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7366** SQLite checks if there are any currently executing SELECT statements 7367** that belong to the same connection. If there are, SQLITE_LOCKED is 7368** returned. In this case there is no "blocking connection", so invoking 7369** sqlite3_unlock_notify() results in the unlock-notify callback being 7370** invoked immediately. If the application then re-attempts the "DROP TABLE" 7371** or "DROP INDEX" query, an infinite loop might be the result. 7372** 7373** One way around this problem is to check the extended error code returned 7374** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7375** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7376** the special "DROP TABLE/INDEX" case, the extended error code is just 7377** SQLITE_LOCKED.)^ 7378*/ 7379int sqlite3_unlock_notify( 7380 sqlite3 *pBlocked, /* Waiting connection */ 7381 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7382 void *pNotifyArg /* Argument to pass to xNotify */ 7383); 7384 7385 7386/* 7387** CAPI3REF: String Comparison 7388** 7389** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7390** and extensions to compare the contents of two buffers containing UTF-8 7391** strings in a case-independent fashion, using the same definition of "case 7392** independence" that SQLite uses internally when comparing identifiers. 7393*/ 7394int sqlite3_stricmp(const char *, const char *); 7395int sqlite3_strnicmp(const char *, const char *, int); 7396 7397/* 7398** CAPI3REF: String Globbing 7399* 7400** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7401** string X matches the [GLOB] pattern P. 7402** ^The definition of [GLOB] pattern matching used in 7403** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7404** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7405** is case sensitive. 7406** 7407** Note that this routine returns zero on a match and non-zero if the strings 7408** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7409** 7410** See also: [sqlite3_strlike()]. 7411*/ 7412int sqlite3_strglob(const char *zGlob, const char *zStr); 7413 7414/* 7415** CAPI3REF: String LIKE Matching 7416* 7417** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7418** string X matches the [LIKE] pattern P with escape character E. 7419** ^The definition of [LIKE] pattern matching used in 7420** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7421** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7422** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7423** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7424** insensitive - equivalent upper and lower case ASCII characters match 7425** one another. 7426** 7427** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7428** only ASCII characters are case folded. 7429** 7430** Note that this routine returns zero on a match and non-zero if the strings 7431** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7432** 7433** See also: [sqlite3_strglob()]. 7434*/ 7435int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7436 7437/* 7438** CAPI3REF: Error Logging Interface 7439** 7440** ^The [sqlite3_log()] interface writes a message into the [error log] 7441** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7442** ^If logging is enabled, the zFormat string and subsequent arguments are 7443** used with [sqlite3_snprintf()] to generate the final output string. 7444** 7445** The sqlite3_log() interface is intended for use by extensions such as 7446** virtual tables, collating functions, and SQL functions. While there is 7447** nothing to prevent an application from calling sqlite3_log(), doing so 7448** is considered bad form. 7449** 7450** The zFormat string must not be NULL. 7451** 7452** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7453** will not use dynamically allocated memory. The log message is stored in 7454** a fixed-length buffer on the stack. If the log message is longer than 7455** a few hundred characters, it will be truncated to the length of the 7456** buffer. 7457*/ 7458void sqlite3_log(int iErrCode, const char *zFormat, ...); 7459 7460/* 7461** CAPI3REF: Write-Ahead Log Commit Hook 7462** METHOD: sqlite3 7463** 7464** ^The [sqlite3_wal_hook()] function is used to register a callback that 7465** is invoked each time data is committed to a database in wal mode. 7466** 7467** ^(The callback is invoked by SQLite after the commit has taken place and 7468** the associated write-lock on the database released)^, so the implementation 7469** may read, write or [checkpoint] the database as required. 7470** 7471** ^The first parameter passed to the callback function when it is invoked 7472** is a copy of the third parameter passed to sqlite3_wal_hook() when 7473** registering the callback. ^The second is a copy of the database handle. 7474** ^The third parameter is the name of the database that was written to - 7475** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7476** is the number of pages currently in the write-ahead log file, 7477** including those that were just committed. 7478** 7479** The callback function should normally return [SQLITE_OK]. ^If an error 7480** code is returned, that error will propagate back up through the 7481** SQLite code base to cause the statement that provoked the callback 7482** to report an error, though the commit will have still occurred. If the 7483** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7484** that does not correspond to any valid SQLite error code, the results 7485** are undefined. 7486** 7487** A single database handle may have at most a single write-ahead log callback 7488** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7489** previously registered write-ahead log callback. ^Note that the 7490** [sqlite3_wal_autocheckpoint()] interface and the 7491** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7492** overwrite any prior [sqlite3_wal_hook()] settings. 7493*/ 7494void *sqlite3_wal_hook( 7495 sqlite3*, 7496 int(*)(void *,sqlite3*,const char*,int), 7497 void* 7498); 7499 7500/* 7501** CAPI3REF: Configure an auto-checkpoint 7502** METHOD: sqlite3 7503** 7504** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 7505** [sqlite3_wal_hook()] that causes any database on [database connection] D 7506** to automatically [checkpoint] 7507** after committing a transaction if there are N or 7508** more frames in the [write-ahead log] file. ^Passing zero or 7509** a negative value as the nFrame parameter disables automatic 7510** checkpoints entirely. 7511** 7512** ^The callback registered by this function replaces any existing callback 7513** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 7514** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 7515** configured by this function. 7516** 7517** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 7518** from SQL. 7519** 7520** ^Checkpoints initiated by this mechanism are 7521** [sqlite3_wal_checkpoint_v2|PASSIVE]. 7522** 7523** ^Every new [database connection] defaults to having the auto-checkpoint 7524** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 7525** pages. The use of this interface 7526** is only necessary if the default setting is found to be suboptimal 7527** for a particular application. 7528*/ 7529int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 7530 7531/* 7532** CAPI3REF: Checkpoint a database 7533** METHOD: sqlite3 7534** 7535** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 7536** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 7537** 7538** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 7539** [write-ahead log] for database X on [database connection] D to be 7540** transferred into the database file and for the write-ahead log to 7541** be reset. See the [checkpointing] documentation for addition 7542** information. 7543** 7544** This interface used to be the only way to cause a checkpoint to 7545** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 7546** interface was added. This interface is retained for backwards 7547** compatibility and as a convenience for applications that need to manually 7548** start a callback but which do not need the full power (and corresponding 7549** complication) of [sqlite3_wal_checkpoint_v2()]. 7550*/ 7551int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 7552 7553/* 7554** CAPI3REF: Checkpoint a database 7555** METHOD: sqlite3 7556** 7557** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 7558** operation on database X of [database connection] D in mode M. Status 7559** information is written back into integers pointed to by L and C.)^ 7560** ^(The M parameter must be a valid [checkpoint mode]:)^ 7561** 7562** <dl> 7563** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7564** ^Checkpoint as many frames as possible without waiting for any database 7565** readers or writers to finish, then sync the database file if all frames 7566** in the log were checkpointed. ^The [busy-handler callback] 7567** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 7568** ^On the other hand, passive mode might leave the checkpoint unfinished 7569** if there are concurrent readers or writers. 7570** 7571** <dt>SQLITE_CHECKPOINT_FULL<dd> 7572** ^This mode blocks (it invokes the 7573** [sqlite3_busy_handler|busy-handler callback]) until there is no 7574** database writer and all readers are reading from the most recent database 7575** snapshot. ^It then checkpoints all frames in the log file and syncs the 7576** database file. ^This mode blocks new database writers while it is pending, 7577** but new database readers are allowed to continue unimpeded. 7578** 7579** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7580** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 7581** that after checkpointing the log file it blocks (calls the 7582** [busy-handler callback]) 7583** until all readers are reading from the database file only. ^This ensures 7584** that the next writer will restart the log file from the beginning. 7585** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 7586** database writer attempts while it is pending, but does not impede readers. 7587** 7588** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 7589** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 7590** addition that it also truncates the log file to zero bytes just prior 7591** to a successful return. 7592** </dl> 7593** 7594** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 7595** the log file or to -1 if the checkpoint could not run because 7596** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 7597** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 7598** log file (including any that were already checkpointed before the function 7599** was called) or to -1 if the checkpoint could not run due to an error or 7600** because the database is not in WAL mode. ^Note that upon successful 7601** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 7602** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 7603** 7604** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 7605** any other process is running a checkpoint operation at the same time, the 7606** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 7607** busy-handler configured, it will not be invoked in this case. 7608** 7609** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 7610** exclusive "writer" lock on the database file. ^If the writer lock cannot be 7611** obtained immediately, and a busy-handler is configured, it is invoked and 7612** the writer lock retried until either the busy-handler returns 0 or the lock 7613** is successfully obtained. ^The busy-handler is also invoked while waiting for 7614** database readers as described above. ^If the busy-handler returns 0 before 7615** the writer lock is obtained or while waiting for database readers, the 7616** checkpoint operation proceeds from that point in the same way as 7617** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7618** without blocking any further. ^SQLITE_BUSY is returned in this case. 7619** 7620** ^If parameter zDb is NULL or points to a zero length string, then the 7621** specified operation is attempted on all WAL databases [attached] to 7622** [database connection] db. In this case the 7623** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 7624** an SQLITE_BUSY error is encountered when processing one or more of the 7625** attached WAL databases, the operation is still attempted on any remaining 7626** attached databases and SQLITE_BUSY is returned at the end. ^If any other 7627** error occurs while processing an attached database, processing is abandoned 7628** and the error code is returned to the caller immediately. ^If no error 7629** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7630** databases, SQLITE_OK is returned. 7631** 7632** ^If database zDb is the name of an attached database that is not in WAL 7633** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 7634** zDb is not NULL (or a zero length string) and is not the name of any 7635** attached database, SQLITE_ERROR is returned to the caller. 7636** 7637** ^Unless it returns SQLITE_MISUSE, 7638** the sqlite3_wal_checkpoint_v2() interface 7639** sets the error information that is queried by 7640** [sqlite3_errcode()] and [sqlite3_errmsg()]. 7641** 7642** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 7643** from SQL. 7644*/ 7645int sqlite3_wal_checkpoint_v2( 7646 sqlite3 *db, /* Database handle */ 7647 const char *zDb, /* Name of attached database (or NULL) */ 7648 int eMode, /* SQLITE_CHECKPOINT_* value */ 7649 int *pnLog, /* OUT: Size of WAL log in frames */ 7650 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7651); 7652 7653/* 7654** CAPI3REF: Checkpoint Mode Values 7655** KEYWORDS: {checkpoint mode} 7656** 7657** These constants define all valid values for the "checkpoint mode" passed 7658** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 7659** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 7660** meaning of each of these checkpoint modes. 7661*/ 7662#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 7663#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 7664#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 7665#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 7666 7667/* 7668** CAPI3REF: Virtual Table Interface Configuration 7669** 7670** This function may be called by either the [xConnect] or [xCreate] method 7671** of a [virtual table] implementation to configure 7672** various facets of the virtual table interface. 7673** 7674** If this interface is invoked outside the context of an xConnect or 7675** xCreate virtual table method then the behavior is undefined. 7676** 7677** At present, there is only one option that may be configured using 7678** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7679** may be added in the future. 7680*/ 7681int sqlite3_vtab_config(sqlite3*, int op, ...); 7682 7683/* 7684** CAPI3REF: Virtual Table Configuration Options 7685** 7686** These macros define the various options to the 7687** [sqlite3_vtab_config()] interface that [virtual table] implementations 7688** can use to customize and optimize their behavior. 7689** 7690** <dl> 7691** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7692** <dd>Calls of the form 7693** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7694** where X is an integer. If X is zero, then the [virtual table] whose 7695** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7696** support constraints. In this configuration (which is the default) if 7697** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7698** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7699** specified as part of the users SQL statement, regardless of the actual 7700** ON CONFLICT mode specified. 7701** 7702** If X is non-zero, then the virtual table implementation guarantees 7703** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7704** any modifications to internal or persistent data structures have been made. 7705** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7706** is able to roll back a statement or database transaction, and abandon 7707** or continue processing the current SQL statement as appropriate. 7708** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7709** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7710** had been ABORT. 7711** 7712** Virtual table implementations that are required to handle OR REPLACE 7713** must do so within the [xUpdate] method. If a call to the 7714** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7715** CONFLICT policy is REPLACE, the virtual table implementation should 7716** silently replace the appropriate rows within the xUpdate callback and 7717** return SQLITE_OK. Or, if this is not possible, it may return 7718** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7719** constraint handling. 7720** </dl> 7721*/ 7722#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7723 7724/* 7725** CAPI3REF: Determine The Virtual Table Conflict Policy 7726** 7727** This function may only be called from within a call to the [xUpdate] method 7728** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7729** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7730** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7731** of the SQL statement that triggered the call to the [xUpdate] method of the 7732** [virtual table]. 7733*/ 7734int sqlite3_vtab_on_conflict(sqlite3 *); 7735 7736/* 7737** CAPI3REF: Conflict resolution modes 7738** KEYWORDS: {conflict resolution mode} 7739** 7740** These constants are returned by [sqlite3_vtab_on_conflict()] to 7741** inform a [virtual table] implementation what the [ON CONFLICT] mode 7742** is for the SQL statement being evaluated. 7743** 7744** Note that the [SQLITE_IGNORE] constant is also used as a potential 7745** return value from the [sqlite3_set_authorizer()] callback and that 7746** [SQLITE_ABORT] is also a [result code]. 7747*/ 7748#define SQLITE_ROLLBACK 1 7749/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7750#define SQLITE_FAIL 3 7751/* #define SQLITE_ABORT 4 // Also an error code */ 7752#define SQLITE_REPLACE 5 7753 7754/* 7755** CAPI3REF: Prepared Statement Scan Status Opcodes 7756** KEYWORDS: {scanstatus options} 7757** 7758** The following constants can be used for the T parameter to the 7759** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 7760** different metric for sqlite3_stmt_scanstatus() to return. 7761** 7762** When the value returned to V is a string, space to hold that string is 7763** managed by the prepared statement S and will be automatically freed when 7764** S is finalized. 7765** 7766** <dl> 7767** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 7768** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 7769** set to the total number of times that the X-th loop has run.</dd> 7770** 7771** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 7772** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 7773** to the total number of rows examined by all iterations of the X-th loop.</dd> 7774** 7775** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 7776** <dd>^The "double" variable pointed to by the T parameter will be set to the 7777** query planner's estimate for the average number of rows output from each 7778** iteration of the X-th loop. If the query planner's estimates was accurate, 7779** then this value will approximate the quotient NVISIT/NLOOP and the 7780** product of this value for all prior loops with the same SELECTID will 7781** be the NLOOP value for the current loop. 7782** 7783** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 7784** <dd>^The "const char *" variable pointed to by the T parameter will be set 7785** to a zero-terminated UTF-8 string containing the name of the index or table 7786** used for the X-th loop. 7787** 7788** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 7789** <dd>^The "const char *" variable pointed to by the T parameter will be set 7790** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 7791** description for the X-th loop. 7792** 7793** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 7794** <dd>^The "int" variable pointed to by the T parameter will be set to the 7795** "select-id" for the X-th loop. The select-id identifies which query or 7796** subquery the loop is part of. The main query has a select-id of zero. 7797** The select-id is the same value as is output in the first column 7798** of an [EXPLAIN QUERY PLAN] query. 7799** </dl> 7800*/ 7801#define SQLITE_SCANSTAT_NLOOP 0 7802#define SQLITE_SCANSTAT_NVISIT 1 7803#define SQLITE_SCANSTAT_EST 2 7804#define SQLITE_SCANSTAT_NAME 3 7805#define SQLITE_SCANSTAT_EXPLAIN 4 7806#define SQLITE_SCANSTAT_SELECTID 5 7807 7808/* 7809** CAPI3REF: Prepared Statement Scan Status 7810** METHOD: sqlite3_stmt 7811** 7812** This interface returns information about the predicted and measured 7813** performance for pStmt. Advanced applications can use this 7814** interface to compare the predicted and the measured performance and 7815** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 7816** 7817** Since this interface is expected to be rarely used, it is only 7818** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 7819** compile-time option. 7820** 7821** The "iScanStatusOp" parameter determines which status information to return. 7822** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 7823** of this interface is undefined. 7824** ^The requested measurement is written into a variable pointed to by 7825** the "pOut" parameter. 7826** Parameter "idx" identifies the specific loop to retrieve statistics for. 7827** Loops are numbered starting from zero. ^If idx is out of range - less than 7828** zero or greater than or equal to the total number of loops used to implement 7829** the statement - a non-zero value is returned and the variable that pOut 7830** points to is unchanged. 7831** 7832** ^Statistics might not be available for all loops in all statements. ^In cases 7833** where there exist loops with no available statistics, this function behaves 7834** as if the loop did not exist - it returns non-zero and leave the variable 7835** that pOut points to unchanged. 7836** 7837** See also: [sqlite3_stmt_scanstatus_reset()] 7838*/ 7839int sqlite3_stmt_scanstatus( 7840 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 7841 int idx, /* Index of loop to report on */ 7842 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 7843 void *pOut /* Result written here */ 7844); 7845 7846/* 7847** CAPI3REF: Zero Scan-Status Counters 7848** METHOD: sqlite3_stmt 7849** 7850** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 7851** 7852** This API is only available if the library is built with pre-processor 7853** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 7854*/ 7855void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 7856 7857/* 7858** CAPI3REF: Flush caches to disk mid-transaction 7859** 7860** ^If a write-transaction is open on [database connection] D when the 7861** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 7862** pages in the pager-cache that are not currently in use are written out 7863** to disk. A dirty page may be in use if a database cursor created by an 7864** active SQL statement is reading from it, or if it is page 1 of a database 7865** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 7866** interface flushes caches for all schemas - "main", "temp", and 7867** any [attached] databases. 7868** 7869** ^If this function needs to obtain extra database locks before dirty pages 7870** can be flushed to disk, it does so. ^If those locks cannot be obtained 7871** immediately and there is a busy-handler callback configured, it is invoked 7872** in the usual manner. ^If the required lock still cannot be obtained, then 7873** the database is skipped and an attempt made to flush any dirty pages 7874** belonging to the next (if any) database. ^If any databases are skipped 7875** because locks cannot be obtained, but no other error occurs, this 7876** function returns SQLITE_BUSY. 7877** 7878** ^If any other error occurs while flushing dirty pages to disk (for 7879** example an IO error or out-of-memory condition), then processing is 7880** abandoned and an SQLite [error code] is returned to the caller immediately. 7881** 7882** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 7883** 7884** ^This function does not set the database handle error code or message 7885** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 7886*/ 7887int sqlite3_db_cacheflush(sqlite3*); 7888 7889/* 7890** CAPI3REF: Database Snapshot 7891** KEYWORDS: {snapshot} 7892** EXPERIMENTAL 7893** 7894** An instance of the snapshot object records the state of a [WAL mode] 7895** database for some specific point in history. 7896** 7897** In [WAL mode], multiple [database connections] that are open on the 7898** same database file can each be reading a different historical version 7899** of the database file. When a [database connection] begins a read 7900** transaction, that connection sees an unchanging copy of the database 7901** as it existed for the point in time when the transaction first started. 7902** Subsequent changes to the database from other connections are not seen 7903** by the reader until a new read transaction is started. 7904** 7905** The sqlite3_snapshot object records state information about an historical 7906** version of the database file so that it is possible to later open a new read 7907** transaction that sees that historical version of the database rather than 7908** the most recent version. 7909** 7910** The constructor for this object is [sqlite3_snapshot_get()]. The 7911** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 7912** to an historical snapshot (if possible). The destructor for 7913** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 7914*/ 7915typedef struct sqlite3_snapshot sqlite3_snapshot; 7916 7917/* 7918** CAPI3REF: Record A Database Snapshot 7919** EXPERIMENTAL 7920** 7921** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 7922** new [sqlite3_snapshot] object that records the current state of 7923** schema S in database connection D. ^On success, the 7924** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 7925** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 7926** ^If schema S of [database connection] D is not a [WAL mode] database 7927** that is in a read transaction, then [sqlite3_snapshot_get(D,S,P)] 7928** leaves the *P value unchanged and returns an appropriate [error code]. 7929** 7930** The [sqlite3_snapshot] object returned from a successful call to 7931** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 7932** to avoid a memory leak. 7933** 7934** The [sqlite3_snapshot_get()] interface is only available when the 7935** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 7936*/ 7937SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 7938 sqlite3 *db, 7939 const char *zSchema, 7940 sqlite3_snapshot **ppSnapshot 7941); 7942 7943/* 7944** CAPI3REF: Start a read transaction on an historical snapshot 7945** EXPERIMENTAL 7946** 7947** ^The [sqlite3_snapshot_open(D,S,P)] interface attempts to move the 7948** read transaction that is currently open on schema S of 7949** [database connection] D so that it refers to historical [snapshot] P. 7950** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 7951** or an appropriate [error code] if it fails. 7952** 7953** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 7954** the first operation, apart from other sqlite3_snapshot_open() calls, 7955** following the [BEGIN] that starts a new read transaction. 7956** ^A [snapshot] will fail to open if it has been overwritten by a 7957** [checkpoint]. 7958** 7959** The [sqlite3_snapshot_open()] interface is only available when the 7960** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 7961*/ 7962SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 7963 sqlite3 *db, 7964 const char *zSchema, 7965 sqlite3_snapshot *pSnapshot 7966); 7967 7968/* 7969** CAPI3REF: Destroy a snapshot 7970** EXPERIMENTAL 7971** 7972** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 7973** The application must eventually free every [sqlite3_snapshot] object 7974** using this routine to avoid a memory leak. 7975** 7976** The [sqlite3_snapshot_free()] interface is only available when the 7977** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 7978*/ 7979SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 7980 7981/* 7982** Undo the hack that converts floating point types to integer for 7983** builds on processors without floating point support. 7984*/ 7985#ifdef SQLITE_OMIT_FLOATING_POINT 7986# undef double 7987#endif 7988 7989#ifdef __cplusplus 7990} /* End of the 'extern "C"' block */ 7991#endif 7992#endif /* _SQLITE3_H_ */ 7993