1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are supposed to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef _SQLITE3_H_ 34#define _SQLITE3_H_ 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_STDCALL 58# define SQLITE_STDCALL 59#endif 60 61/* 62** These no-op macros are used in front of interfaces to mark those 63** interfaces as either deprecated or experimental. New applications 64** should not use deprecated interfaces - they are supported for backwards 65** compatibility only. Application writers should be aware that 66** experimental interfaces are subject to change in point releases. 67** 68** These macros used to resolve to various kinds of compiler magic that 69** would generate warning messages when they were used. But that 70** compiler magic ended up generating such a flurry of bug reports 71** that we have taken it all out and gone back to using simple 72** noop macros. 73*/ 74#define SQLITE_DEPRECATED 75#define SQLITE_EXPERIMENTAL 76 77/* 78** Ensure these symbols were not defined by some previous header file. 79*/ 80#ifdef SQLITE_VERSION 81# undef SQLITE_VERSION 82#endif 83#ifdef SQLITE_VERSION_NUMBER 84# undef SQLITE_VERSION_NUMBER 85#endif 86 87/* 88** CAPI3REF: Compile-Time Library Version Numbers 89** 90** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 91** evaluates to a string literal that is the SQLite version in the 92** format "X.Y.Z" where X is the major version number (always 3 for 93** SQLite3) and Y is the minor version number and Z is the release number.)^ 94** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 95** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 96** numbers used in [SQLITE_VERSION].)^ 97** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 98** be larger than the release from which it is derived. Either Y will 99** be held constant and Z will be incremented or else Y will be incremented 100** and Z will be reset to zero. 101** 102** Since version 3.6.18, SQLite source code has been stored in the 103** <a href="http://www.fossil-scm.org/">Fossil configuration management 104** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 105** a string which identifies a particular check-in of SQLite 106** within its configuration management system. ^The SQLITE_SOURCE_ID 107** string contains the date and time of the check-in (UTC) and an SHA1 108** hash of the entire source tree. 109** 110** See also: [sqlite3_libversion()], 111** [sqlite3_libversion_number()], [sqlite3_sourceid()], 112** [sqlite_version()] and [sqlite_source_id()]. 113*/ 114#define SQLITE_VERSION "--VERS--" 115#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 116#define SQLITE_SOURCE_ID "--SOURCE-ID--" 117 118/* 119** CAPI3REF: Run-Time Library Version Numbers 120** KEYWORDS: sqlite3_version, sqlite3_sourceid 121** 122** These interfaces provide the same information as the [SQLITE_VERSION], 123** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 124** but are associated with the library instead of the header file. ^(Cautious 125** programmers might include assert() statements in their application to 126** verify that values returned by these interfaces match the macros in 127** the header, and thus ensure that the application is 128** compiled with matching library and header files. 129** 130** <blockquote><pre> 131** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 132** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 133** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 134** </pre></blockquote>)^ 135** 136** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 137** macro. ^The sqlite3_libversion() function returns a pointer to the 138** to the sqlite3_version[] string constant. The sqlite3_libversion() 139** function is provided for use in DLLs since DLL users usually do not have 140** direct access to string constants within the DLL. ^The 141** sqlite3_libversion_number() function returns an integer equal to 142** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 143** a pointer to a string constant whose value is the same as the 144** [SQLITE_SOURCE_ID] C preprocessor macro. 145** 146** See also: [sqlite_version()] and [sqlite_source_id()]. 147*/ 148SQLITE_EXTERN const char sqlite3_version[]; 149const char *sqlite3_libversion(void); 150const char *sqlite3_sourceid(void); 151int sqlite3_libversion_number(void); 152 153/* 154** CAPI3REF: Run-Time Library Compilation Options Diagnostics 155** 156** ^The sqlite3_compileoption_used() function returns 0 or 1 157** indicating whether the specified option was defined at 158** compile time. ^The SQLITE_ prefix may be omitted from the 159** option name passed to sqlite3_compileoption_used(). 160** 161** ^The sqlite3_compileoption_get() function allows iterating 162** over the list of options that were defined at compile time by 163** returning the N-th compile time option string. ^If N is out of range, 164** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 165** prefix is omitted from any strings returned by 166** sqlite3_compileoption_get(). 167** 168** ^Support for the diagnostic functions sqlite3_compileoption_used() 169** and sqlite3_compileoption_get() may be omitted by specifying the 170** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 171** 172** See also: SQL functions [sqlite_compileoption_used()] and 173** [sqlite_compileoption_get()] and the [compile_options pragma]. 174*/ 175#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 176int sqlite3_compileoption_used(const char *zOptName); 177const char *sqlite3_compileoption_get(int N); 178#endif 179 180/* 181** CAPI3REF: Test To See If The Library Is Threadsafe 182** 183** ^The sqlite3_threadsafe() function returns zero if and only if 184** SQLite was compiled with mutexing code omitted due to the 185** [SQLITE_THREADSAFE] compile-time option being set to 0. 186** 187** SQLite can be compiled with or without mutexes. When 188** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 189** are enabled and SQLite is threadsafe. When the 190** [SQLITE_THREADSAFE] macro is 0, 191** the mutexes are omitted. Without the mutexes, it is not safe 192** to use SQLite concurrently from more than one thread. 193** 194** Enabling mutexes incurs a measurable performance penalty. 195** So if speed is of utmost importance, it makes sense to disable 196** the mutexes. But for maximum safety, mutexes should be enabled. 197** ^The default behavior is for mutexes to be enabled. 198** 199** This interface can be used by an application to make sure that the 200** version of SQLite that it is linking against was compiled with 201** the desired setting of the [SQLITE_THREADSAFE] macro. 202** 203** This interface only reports on the compile-time mutex setting 204** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 205** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 206** can be fully or partially disabled using a call to [sqlite3_config()] 207** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 208** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 209** sqlite3_threadsafe() function shows only the compile-time setting of 210** thread safety, not any run-time changes to that setting made by 211** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 212** is unchanged by calls to sqlite3_config().)^ 213** 214** See the [threading mode] documentation for additional information. 215*/ 216int sqlite3_threadsafe(void); 217 218/* 219** CAPI3REF: Database Connection Handle 220** KEYWORDS: {database connection} {database connections} 221** 222** Each open SQLite database is represented by a pointer to an instance of 223** the opaque structure named "sqlite3". It is useful to think of an sqlite3 224** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 225** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 226** and [sqlite3_close_v2()] are its destructors. There are many other 227** interfaces (such as 228** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 229** [sqlite3_busy_timeout()] to name but three) that are methods on an 230** sqlite3 object. 231*/ 232typedef struct sqlite3 sqlite3; 233 234/* 235** CAPI3REF: 64-Bit Integer Types 236** KEYWORDS: sqlite_int64 sqlite_uint64 237** 238** Because there is no cross-platform way to specify 64-bit integer types 239** SQLite includes typedefs for 64-bit signed and unsigned integers. 240** 241** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 242** The sqlite_int64 and sqlite_uint64 types are supported for backwards 243** compatibility only. 244** 245** ^The sqlite3_int64 and sqlite_int64 types can store integer values 246** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 247** sqlite3_uint64 and sqlite_uint64 types can store integer values 248** between 0 and +18446744073709551615 inclusive. 249*/ 250#ifdef SQLITE_INT64_TYPE 251 typedef SQLITE_INT64_TYPE sqlite_int64; 252 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 253#elif defined(_MSC_VER) || defined(__BORLANDC__) 254 typedef __int64 sqlite_int64; 255 typedef unsigned __int64 sqlite_uint64; 256#else 257 typedef long long int sqlite_int64; 258 typedef unsigned long long int sqlite_uint64; 259#endif 260typedef sqlite_int64 sqlite3_int64; 261typedef sqlite_uint64 sqlite3_uint64; 262 263/* 264** If compiling for a processor that lacks floating point support, 265** substitute integer for floating-point. 266*/ 267#ifdef SQLITE_OMIT_FLOATING_POINT 268# define double sqlite3_int64 269#endif 270 271/* 272** CAPI3REF: Closing A Database Connection 273** DESTRUCTOR: sqlite3 274** 275** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 276** for the [sqlite3] object. 277** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 278** the [sqlite3] object is successfully destroyed and all associated 279** resources are deallocated. 280** 281** ^If the database connection is associated with unfinalized prepared 282** statements or unfinished sqlite3_backup objects then sqlite3_close() 283** will leave the database connection open and return [SQLITE_BUSY]. 284** ^If sqlite3_close_v2() is called with unfinalized prepared statements 285** and/or unfinished sqlite3_backups, then the database connection becomes 286** an unusable "zombie" which will automatically be deallocated when the 287** last prepared statement is finalized or the last sqlite3_backup is 288** finished. The sqlite3_close_v2() interface is intended for use with 289** host languages that are garbage collected, and where the order in which 290** destructors are called is arbitrary. 291** 292** Applications should [sqlite3_finalize | finalize] all [prepared statements], 293** [sqlite3_blob_close | close] all [BLOB handles], and 294** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 295** with the [sqlite3] object prior to attempting to close the object. ^If 296** sqlite3_close_v2() is called on a [database connection] that still has 297** outstanding [prepared statements], [BLOB handles], and/or 298** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 299** of resources is deferred until all [prepared statements], [BLOB handles], 300** and [sqlite3_backup] objects are also destroyed. 301** 302** ^If an [sqlite3] object is destroyed while a transaction is open, 303** the transaction is automatically rolled back. 304** 305** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 306** must be either a NULL 307** pointer or an [sqlite3] object pointer obtained 308** from [sqlite3_open()], [sqlite3_open16()], or 309** [sqlite3_open_v2()], and not previously closed. 310** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 311** argument is a harmless no-op. 312*/ 313int sqlite3_close(sqlite3*); 314int sqlite3_close_v2(sqlite3*); 315 316/* 317** The type for a callback function. 318** This is legacy and deprecated. It is included for historical 319** compatibility and is not documented. 320*/ 321typedef int (*sqlite3_callback)(void*,int,char**, char**); 322 323/* 324** CAPI3REF: One-Step Query Execution Interface 325** METHOD: sqlite3 326** 327** The sqlite3_exec() interface is a convenience wrapper around 328** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 329** that allows an application to run multiple statements of SQL 330** without having to use a lot of C code. 331** 332** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 333** semicolon-separate SQL statements passed into its 2nd argument, 334** in the context of the [database connection] passed in as its 1st 335** argument. ^If the callback function of the 3rd argument to 336** sqlite3_exec() is not NULL, then it is invoked for each result row 337** coming out of the evaluated SQL statements. ^The 4th argument to 338** sqlite3_exec() is relayed through to the 1st argument of each 339** callback invocation. ^If the callback pointer to sqlite3_exec() 340** is NULL, then no callback is ever invoked and result rows are 341** ignored. 342** 343** ^If an error occurs while evaluating the SQL statements passed into 344** sqlite3_exec(), then execution of the current statement stops and 345** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 346** is not NULL then any error message is written into memory obtained 347** from [sqlite3_malloc()] and passed back through the 5th parameter. 348** To avoid memory leaks, the application should invoke [sqlite3_free()] 349** on error message strings returned through the 5th parameter of 350** of sqlite3_exec() after the error message string is no longer needed. 351** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 352** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 353** NULL before returning. 354** 355** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 356** routine returns SQLITE_ABORT without invoking the callback again and 357** without running any subsequent SQL statements. 358** 359** ^The 2nd argument to the sqlite3_exec() callback function is the 360** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 361** callback is an array of pointers to strings obtained as if from 362** [sqlite3_column_text()], one for each column. ^If an element of a 363** result row is NULL then the corresponding string pointer for the 364** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 365** sqlite3_exec() callback is an array of pointers to strings where each 366** entry represents the name of corresponding result column as obtained 367** from [sqlite3_column_name()]. 368** 369** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 370** to an empty string, or a pointer that contains only whitespace and/or 371** SQL comments, then no SQL statements are evaluated and the database 372** is not changed. 373** 374** Restrictions: 375** 376** <ul> 377** <li> The application must ensure that the 1st parameter to sqlite3_exec() 378** is a valid and open [database connection]. 379** <li> The application must not close the [database connection] specified by 380** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 381** <li> The application must not modify the SQL statement text passed into 382** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 383** </ul> 384*/ 385int sqlite3_exec( 386 sqlite3*, /* An open database */ 387 const char *sql, /* SQL to be evaluated */ 388 int (*callback)(void*,int,char**,char**), /* Callback function */ 389 void *, /* 1st argument to callback */ 390 char **errmsg /* Error msg written here */ 391); 392 393/* 394** CAPI3REF: Result Codes 395** KEYWORDS: {result code definitions} 396** 397** Many SQLite functions return an integer result code from the set shown 398** here in order to indicate success or failure. 399** 400** New error codes may be added in future versions of SQLite. 401** 402** See also: [extended result code definitions] 403*/ 404#define SQLITE_OK 0 /* Successful result */ 405/* beginning-of-error-codes */ 406#define SQLITE_ERROR 1 /* SQL error or missing database */ 407#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 408#define SQLITE_PERM 3 /* Access permission denied */ 409#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 410#define SQLITE_BUSY 5 /* The database file is locked */ 411#define SQLITE_LOCKED 6 /* A table in the database is locked */ 412#define SQLITE_NOMEM 7 /* A malloc() failed */ 413#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 414#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 415#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 416#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 417#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 418#define SQLITE_FULL 13 /* Insertion failed because database is full */ 419#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 420#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 421#define SQLITE_EMPTY 16 /* Database is empty */ 422#define SQLITE_SCHEMA 17 /* The database schema changed */ 423#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 424#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 425#define SQLITE_MISMATCH 20 /* Data type mismatch */ 426#define SQLITE_MISUSE 21 /* Library used incorrectly */ 427#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 428#define SQLITE_AUTH 23 /* Authorization denied */ 429#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 430#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 431#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 432#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 433#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 434#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 435#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 436/* end-of-error-codes */ 437 438/* 439** CAPI3REF: Extended Result Codes 440** KEYWORDS: {extended result code definitions} 441** 442** In its default configuration, SQLite API routines return one of 30 integer 443** [result codes]. However, experience has shown that many of 444** these result codes are too coarse-grained. They do not provide as 445** much information about problems as programmers might like. In an effort to 446** address this, newer versions of SQLite (version 3.3.8 and later) include 447** support for additional result codes that provide more detailed information 448** about errors. These [extended result codes] are enabled or disabled 449** on a per database connection basis using the 450** [sqlite3_extended_result_codes()] API. Or, the extended code for 451** the most recent error can be obtained using 452** [sqlite3_extended_errcode()]. 453*/ 454#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 455#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 456#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 457#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 458#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 459#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 460#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 461#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 462#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 463#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 464#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 465#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 466#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 467#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 468#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 469#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 470#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 471#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 472#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 473#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 474#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 475#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 476#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 477#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 478#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 479#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 480#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 481#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 482#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 483#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 484#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 485#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 486#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 487#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 488#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 489#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 490#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 491#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 492#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 493#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 494#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 495#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 496#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 497#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 498#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 499#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 500#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 501#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 502#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 503#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 504#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 505#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 506#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 507#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 508#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 509 510/* 511** CAPI3REF: Flags For File Open Operations 512** 513** These bit values are intended for use in the 514** 3rd parameter to the [sqlite3_open_v2()] interface and 515** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 516*/ 517#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 518#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 519#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 520#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 521#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 522#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 523#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 524#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 525#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 526#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 527#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 528#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 529#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 530#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 531#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 532#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 533#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 534#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 535#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 536#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 537 538/* Reserved: 0x00F00000 */ 539 540/* 541** CAPI3REF: Device Characteristics 542** 543** The xDeviceCharacteristics method of the [sqlite3_io_methods] 544** object returns an integer which is a vector of these 545** bit values expressing I/O characteristics of the mass storage 546** device that holds the file that the [sqlite3_io_methods] 547** refers to. 548** 549** The SQLITE_IOCAP_ATOMIC property means that all writes of 550** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 551** mean that writes of blocks that are nnn bytes in size and 552** are aligned to an address which is an integer multiple of 553** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 554** that when data is appended to a file, the data is appended 555** first then the size of the file is extended, never the other 556** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 557** information is written to disk in the same order as calls 558** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 559** after reboot following a crash or power loss, the only bytes in a 560** file that were written at the application level might have changed 561** and that adjacent bytes, even bytes within the same sector are 562** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 563** flag indicate that a file cannot be deleted when open. The 564** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 565** read-only media and cannot be changed even by processes with 566** elevated privileges. 567*/ 568#define SQLITE_IOCAP_ATOMIC 0x00000001 569#define SQLITE_IOCAP_ATOMIC512 0x00000002 570#define SQLITE_IOCAP_ATOMIC1K 0x00000004 571#define SQLITE_IOCAP_ATOMIC2K 0x00000008 572#define SQLITE_IOCAP_ATOMIC4K 0x00000010 573#define SQLITE_IOCAP_ATOMIC8K 0x00000020 574#define SQLITE_IOCAP_ATOMIC16K 0x00000040 575#define SQLITE_IOCAP_ATOMIC32K 0x00000080 576#define SQLITE_IOCAP_ATOMIC64K 0x00000100 577#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 578#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 579#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 580#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 581#define SQLITE_IOCAP_IMMUTABLE 0x00002000 582 583/* 584** CAPI3REF: File Locking Levels 585** 586** SQLite uses one of these integer values as the second 587** argument to calls it makes to the xLock() and xUnlock() methods 588** of an [sqlite3_io_methods] object. 589*/ 590#define SQLITE_LOCK_NONE 0 591#define SQLITE_LOCK_SHARED 1 592#define SQLITE_LOCK_RESERVED 2 593#define SQLITE_LOCK_PENDING 3 594#define SQLITE_LOCK_EXCLUSIVE 4 595 596/* 597** CAPI3REF: Synchronization Type Flags 598** 599** When SQLite invokes the xSync() method of an 600** [sqlite3_io_methods] object it uses a combination of 601** these integer values as the second argument. 602** 603** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 604** sync operation only needs to flush data to mass storage. Inode 605** information need not be flushed. If the lower four bits of the flag 606** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 607** If the lower four bits equal SQLITE_SYNC_FULL, that means 608** to use Mac OS X style fullsync instead of fsync(). 609** 610** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 611** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 612** settings. The [synchronous pragma] determines when calls to the 613** xSync VFS method occur and applies uniformly across all platforms. 614** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 615** energetic or rigorous or forceful the sync operations are and 616** only make a difference on Mac OSX for the default SQLite code. 617** (Third-party VFS implementations might also make the distinction 618** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 619** operating systems natively supported by SQLite, only Mac OSX 620** cares about the difference.) 621*/ 622#define SQLITE_SYNC_NORMAL 0x00002 623#define SQLITE_SYNC_FULL 0x00003 624#define SQLITE_SYNC_DATAONLY 0x00010 625 626/* 627** CAPI3REF: OS Interface Open File Handle 628** 629** An [sqlite3_file] object represents an open file in the 630** [sqlite3_vfs | OS interface layer]. Individual OS interface 631** implementations will 632** want to subclass this object by appending additional fields 633** for their own use. The pMethods entry is a pointer to an 634** [sqlite3_io_methods] object that defines methods for performing 635** I/O operations on the open file. 636*/ 637typedef struct sqlite3_file sqlite3_file; 638struct sqlite3_file { 639 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 640}; 641 642/* 643** CAPI3REF: OS Interface File Virtual Methods Object 644** 645** Every file opened by the [sqlite3_vfs.xOpen] method populates an 646** [sqlite3_file] object (or, more commonly, a subclass of the 647** [sqlite3_file] object) with a pointer to an instance of this object. 648** This object defines the methods used to perform various operations 649** against the open file represented by the [sqlite3_file] object. 650** 651** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 652** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 653** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 654** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 655** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 656** to NULL. 657** 658** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 659** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 660** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 661** flag may be ORed in to indicate that only the data of the file 662** and not its inode needs to be synced. 663** 664** The integer values to xLock() and xUnlock() are one of 665** <ul> 666** <li> [SQLITE_LOCK_NONE], 667** <li> [SQLITE_LOCK_SHARED], 668** <li> [SQLITE_LOCK_RESERVED], 669** <li> [SQLITE_LOCK_PENDING], or 670** <li> [SQLITE_LOCK_EXCLUSIVE]. 671** </ul> 672** xLock() increases the lock. xUnlock() decreases the lock. 673** The xCheckReservedLock() method checks whether any database connection, 674** either in this process or in some other process, is holding a RESERVED, 675** PENDING, or EXCLUSIVE lock on the file. It returns true 676** if such a lock exists and false otherwise. 677** 678** The xFileControl() method is a generic interface that allows custom 679** VFS implementations to directly control an open file using the 680** [sqlite3_file_control()] interface. The second "op" argument is an 681** integer opcode. The third argument is a generic pointer intended to 682** point to a structure that may contain arguments or space in which to 683** write return values. Potential uses for xFileControl() might be 684** functions to enable blocking locks with timeouts, to change the 685** locking strategy (for example to use dot-file locks), to inquire 686** about the status of a lock, or to break stale locks. The SQLite 687** core reserves all opcodes less than 100 for its own use. 688** A [file control opcodes | list of opcodes] less than 100 is available. 689** Applications that define a custom xFileControl method should use opcodes 690** greater than 100 to avoid conflicts. VFS implementations should 691** return [SQLITE_NOTFOUND] for file control opcodes that they do not 692** recognize. 693** 694** The xSectorSize() method returns the sector size of the 695** device that underlies the file. The sector size is the 696** minimum write that can be performed without disturbing 697** other bytes in the file. The xDeviceCharacteristics() 698** method returns a bit vector describing behaviors of the 699** underlying device: 700** 701** <ul> 702** <li> [SQLITE_IOCAP_ATOMIC] 703** <li> [SQLITE_IOCAP_ATOMIC512] 704** <li> [SQLITE_IOCAP_ATOMIC1K] 705** <li> [SQLITE_IOCAP_ATOMIC2K] 706** <li> [SQLITE_IOCAP_ATOMIC4K] 707** <li> [SQLITE_IOCAP_ATOMIC8K] 708** <li> [SQLITE_IOCAP_ATOMIC16K] 709** <li> [SQLITE_IOCAP_ATOMIC32K] 710** <li> [SQLITE_IOCAP_ATOMIC64K] 711** <li> [SQLITE_IOCAP_SAFE_APPEND] 712** <li> [SQLITE_IOCAP_SEQUENTIAL] 713** </ul> 714** 715** The SQLITE_IOCAP_ATOMIC property means that all writes of 716** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 717** mean that writes of blocks that are nnn bytes in size and 718** are aligned to an address which is an integer multiple of 719** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 720** that when data is appended to a file, the data is appended 721** first then the size of the file is extended, never the other 722** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 723** information is written to disk in the same order as calls 724** to xWrite(). 725** 726** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 727** in the unread portions of the buffer with zeros. A VFS that 728** fails to zero-fill short reads might seem to work. However, 729** failure to zero-fill short reads will eventually lead to 730** database corruption. 731*/ 732typedef struct sqlite3_io_methods sqlite3_io_methods; 733struct sqlite3_io_methods { 734 int iVersion; 735 int (*xClose)(sqlite3_file*); 736 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 737 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 738 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 739 int (*xSync)(sqlite3_file*, int flags); 740 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 741 int (*xLock)(sqlite3_file*, int); 742 int (*xUnlock)(sqlite3_file*, int); 743 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 744 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 745 int (*xSectorSize)(sqlite3_file*); 746 int (*xDeviceCharacteristics)(sqlite3_file*); 747 /* Methods above are valid for version 1 */ 748 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 749 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 750 void (*xShmBarrier)(sqlite3_file*); 751 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 752 /* Methods above are valid for version 2 */ 753 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 754 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 755 /* Methods above are valid for version 3 */ 756 /* Additional methods may be added in future releases */ 757}; 758 759/* 760** CAPI3REF: Standard File Control Opcodes 761** KEYWORDS: {file control opcodes} {file control opcode} 762** 763** These integer constants are opcodes for the xFileControl method 764** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 765** interface. 766** 767** <ul> 768** <li>[[SQLITE_FCNTL_LOCKSTATE]] 769** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 770** opcode causes the xFileControl method to write the current state of 771** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 772** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 773** into an integer that the pArg argument points to. This capability 774** is used during testing and is only available when the SQLITE_TEST 775** compile-time option is used. 776** 777** <li>[[SQLITE_FCNTL_SIZE_HINT]] 778** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 779** layer a hint of how large the database file will grow to be during the 780** current transaction. This hint is not guaranteed to be accurate but it 781** is often close. The underlying VFS might choose to preallocate database 782** file space based on this hint in order to help writes to the database 783** file run faster. 784** 785** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 786** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 787** extends and truncates the database file in chunks of a size specified 788** by the user. The fourth argument to [sqlite3_file_control()] should 789** point to an integer (type int) containing the new chunk-size to use 790** for the nominated database. Allocating database file space in large 791** chunks (say 1MB at a time), may reduce file-system fragmentation and 792** improve performance on some systems. 793** 794** <li>[[SQLITE_FCNTL_FILE_POINTER]] 795** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 796** to the [sqlite3_file] object associated with a particular database 797** connection. See the [sqlite3_file_control()] documentation for 798** additional information. 799** 800** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 801** No longer in use. 802** 803** <li>[[SQLITE_FCNTL_SYNC]] 804** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 805** sent to the VFS immediately before the xSync method is invoked on a 806** database file descriptor. Or, if the xSync method is not invoked 807** because the user has configured SQLite with 808** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 809** of the xSync method. In most cases, the pointer argument passed with 810** this file-control is NULL. However, if the database file is being synced 811** as part of a multi-database commit, the argument points to a nul-terminated 812** string containing the transactions master-journal file name. VFSes that 813** do not need this signal should silently ignore this opcode. Applications 814** should not call [sqlite3_file_control()] with this opcode as doing so may 815** disrupt the operation of the specialized VFSes that do require it. 816** 817** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 818** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 819** and sent to the VFS after a transaction has been committed immediately 820** but before the database is unlocked. VFSes that do not need this signal 821** should silently ignore this opcode. Applications should not call 822** [sqlite3_file_control()] with this opcode as doing so may disrupt the 823** operation of the specialized VFSes that do require it. 824** 825** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 826** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 827** retry counts and intervals for certain disk I/O operations for the 828** windows [VFS] in order to provide robustness in the presence of 829** anti-virus programs. By default, the windows VFS will retry file read, 830** file write, and file delete operations up to 10 times, with a delay 831** of 25 milliseconds before the first retry and with the delay increasing 832** by an additional 25 milliseconds with each subsequent retry. This 833** opcode allows these two values (10 retries and 25 milliseconds of delay) 834** to be adjusted. The values are changed for all database connections 835** within the same process. The argument is a pointer to an array of two 836** integers where the first integer i the new retry count and the second 837** integer is the delay. If either integer is negative, then the setting 838** is not changed but instead the prior value of that setting is written 839** into the array entry, allowing the current retry settings to be 840** interrogated. The zDbName parameter is ignored. 841** 842** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 843** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 844** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 845** write ahead log and shared memory files used for transaction control 846** are automatically deleted when the latest connection to the database 847** closes. Setting persistent WAL mode causes those files to persist after 848** close. Persisting the files is useful when other processes that do not 849** have write permission on the directory containing the database file want 850** to read the database file, as the WAL and shared memory files must exist 851** in order for the database to be readable. The fourth parameter to 852** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 853** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 854** WAL mode. If the integer is -1, then it is overwritten with the current 855** WAL persistence setting. 856** 857** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 858** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 859** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 860** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 861** xDeviceCharacteristics methods. The fourth parameter to 862** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 863** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 864** mode. If the integer is -1, then it is overwritten with the current 865** zero-damage mode setting. 866** 867** <li>[[SQLITE_FCNTL_OVERWRITE]] 868** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 869** a write transaction to indicate that, unless it is rolled back for some 870** reason, the entire database file will be overwritten by the current 871** transaction. This is used by VACUUM operations. 872** 873** <li>[[SQLITE_FCNTL_VFSNAME]] 874** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 875** all [VFSes] in the VFS stack. The names are of all VFS shims and the 876** final bottom-level VFS are written into memory obtained from 877** [sqlite3_malloc()] and the result is stored in the char* variable 878** that the fourth parameter of [sqlite3_file_control()] points to. 879** The caller is responsible for freeing the memory when done. As with 880** all file-control actions, there is no guarantee that this will actually 881** do anything. Callers should initialize the char* variable to a NULL 882** pointer in case this file-control is not implemented. This file-control 883** is intended for diagnostic use only. 884** 885** <li>[[SQLITE_FCNTL_PRAGMA]] 886** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 887** file control is sent to the open [sqlite3_file] object corresponding 888** to the database file to which the pragma statement refers. ^The argument 889** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 890** pointers to strings (char**) in which the second element of the array 891** is the name of the pragma and the third element is the argument to the 892** pragma or NULL if the pragma has no argument. ^The handler for an 893** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 894** of the char** argument point to a string obtained from [sqlite3_mprintf()] 895** or the equivalent and that string will become the result of the pragma or 896** the error message if the pragma fails. ^If the 897** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 898** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 899** file control returns [SQLITE_OK], then the parser assumes that the 900** VFS has handled the PRAGMA itself and the parser generates a no-op 901** prepared statement if result string is NULL, or that returns a copy 902** of the result string if the string is non-NULL. 903** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 904** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 905** that the VFS encountered an error while handling the [PRAGMA] and the 906** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 907** file control occurs at the beginning of pragma statement analysis and so 908** it is able to override built-in [PRAGMA] statements. 909** 910** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 911** ^The [SQLITE_FCNTL_BUSYHANDLER] 912** file-control may be invoked by SQLite on the database file handle 913** shortly after it is opened in order to provide a custom VFS with access 914** to the connections busy-handler callback. The argument is of type (void **) 915** - an array of two (void *) values. The first (void *) actually points 916** to a function of type (int (*)(void *)). In order to invoke the connections 917** busy-handler, this function should be invoked with the second (void *) in 918** the array as the only argument. If it returns non-zero, then the operation 919** should be retried. If it returns zero, the custom VFS should abandon the 920** current operation. 921** 922** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 923** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 924** to have SQLite generate a 925** temporary filename using the same algorithm that is followed to generate 926** temporary filenames for TEMP tables and other internal uses. The 927** argument should be a char** which will be filled with the filename 928** written into memory obtained from [sqlite3_malloc()]. The caller should 929** invoke [sqlite3_free()] on the result to avoid a memory leak. 930** 931** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 932** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 933** maximum number of bytes that will be used for memory-mapped I/O. 934** The argument is a pointer to a value of type sqlite3_int64 that 935** is an advisory maximum number of bytes in the file to memory map. The 936** pointer is overwritten with the old value. The limit is not changed if 937** the value originally pointed to is negative, and so the current limit 938** can be queried by passing in a pointer to a negative number. This 939** file-control is used internally to implement [PRAGMA mmap_size]. 940** 941** <li>[[SQLITE_FCNTL_TRACE]] 942** The [SQLITE_FCNTL_TRACE] file control provides advisory information 943** to the VFS about what the higher layers of the SQLite stack are doing. 944** This file control is used by some VFS activity tracing [shims]. 945** The argument is a zero-terminated string. Higher layers in the 946** SQLite stack may generate instances of this file control if 947** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 948** 949** <li>[[SQLITE_FCNTL_HAS_MOVED]] 950** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 951** pointer to an integer and it writes a boolean into that integer depending 952** on whether or not the file has been renamed, moved, or deleted since it 953** was first opened. 954** 955** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 956** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 957** opcode causes the xFileControl method to swap the file handle with the one 958** pointed to by the pArg argument. This capability is used during testing 959** and only needs to be supported when SQLITE_TEST is defined. 960** 961** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 962** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 963** be advantageous to block on the next WAL lock if the lock is not immediately 964** available. The WAL subsystem issues this signal during rare 965** circumstances in order to fix a problem with priority inversion. 966** Applications should <em>not</em> use this file-control. 967** 968** <li>[[SQLITE_FCNTL_ZIPVFS]] 969** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 970** VFS should return SQLITE_NOTFOUND for this opcode. 971** 972** <li>[[SQLITE_FCNTL_RBU]] 973** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 974** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 975** this opcode. 976** </ul> 977*/ 978#define SQLITE_FCNTL_LOCKSTATE 1 979#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 980#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 981#define SQLITE_FCNTL_LAST_ERRNO 4 982#define SQLITE_FCNTL_SIZE_HINT 5 983#define SQLITE_FCNTL_CHUNK_SIZE 6 984#define SQLITE_FCNTL_FILE_POINTER 7 985#define SQLITE_FCNTL_SYNC_OMITTED 8 986#define SQLITE_FCNTL_WIN32_AV_RETRY 9 987#define SQLITE_FCNTL_PERSIST_WAL 10 988#define SQLITE_FCNTL_OVERWRITE 11 989#define SQLITE_FCNTL_VFSNAME 12 990#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 991#define SQLITE_FCNTL_PRAGMA 14 992#define SQLITE_FCNTL_BUSYHANDLER 15 993#define SQLITE_FCNTL_TEMPFILENAME 16 994#define SQLITE_FCNTL_MMAP_SIZE 18 995#define SQLITE_FCNTL_TRACE 19 996#define SQLITE_FCNTL_HAS_MOVED 20 997#define SQLITE_FCNTL_SYNC 21 998#define SQLITE_FCNTL_COMMIT_PHASETWO 22 999#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1000#define SQLITE_FCNTL_WAL_BLOCK 24 1001#define SQLITE_FCNTL_ZIPVFS 25 1002#define SQLITE_FCNTL_RBU 26 1003 1004/* deprecated names */ 1005#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1006#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1007#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1008 1009 1010/* 1011** CAPI3REF: Mutex Handle 1012** 1013** The mutex module within SQLite defines [sqlite3_mutex] to be an 1014** abstract type for a mutex object. The SQLite core never looks 1015** at the internal representation of an [sqlite3_mutex]. It only 1016** deals with pointers to the [sqlite3_mutex] object. 1017** 1018** Mutexes are created using [sqlite3_mutex_alloc()]. 1019*/ 1020typedef struct sqlite3_mutex sqlite3_mutex; 1021 1022/* 1023** CAPI3REF: OS Interface Object 1024** 1025** An instance of the sqlite3_vfs object defines the interface between 1026** the SQLite core and the underlying operating system. The "vfs" 1027** in the name of the object stands for "virtual file system". See 1028** the [VFS | VFS documentation] for further information. 1029** 1030** The value of the iVersion field is initially 1 but may be larger in 1031** future versions of SQLite. Additional fields may be appended to this 1032** object when the iVersion value is increased. Note that the structure 1033** of the sqlite3_vfs object changes in the transaction between 1034** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1035** modified. 1036** 1037** The szOsFile field is the size of the subclassed [sqlite3_file] 1038** structure used by this VFS. mxPathname is the maximum length of 1039** a pathname in this VFS. 1040** 1041** Registered sqlite3_vfs objects are kept on a linked list formed by 1042** the pNext pointer. The [sqlite3_vfs_register()] 1043** and [sqlite3_vfs_unregister()] interfaces manage this list 1044** in a thread-safe way. The [sqlite3_vfs_find()] interface 1045** searches the list. Neither the application code nor the VFS 1046** implementation should use the pNext pointer. 1047** 1048** The pNext field is the only field in the sqlite3_vfs 1049** structure that SQLite will ever modify. SQLite will only access 1050** or modify this field while holding a particular static mutex. 1051** The application should never modify anything within the sqlite3_vfs 1052** object once the object has been registered. 1053** 1054** The zName field holds the name of the VFS module. The name must 1055** be unique across all VFS modules. 1056** 1057** [[sqlite3_vfs.xOpen]] 1058** ^SQLite guarantees that the zFilename parameter to xOpen 1059** is either a NULL pointer or string obtained 1060** from xFullPathname() with an optional suffix added. 1061** ^If a suffix is added to the zFilename parameter, it will 1062** consist of a single "-" character followed by no more than 1063** 11 alphanumeric and/or "-" characters. 1064** ^SQLite further guarantees that 1065** the string will be valid and unchanged until xClose() is 1066** called. Because of the previous sentence, 1067** the [sqlite3_file] can safely store a pointer to the 1068** filename if it needs to remember the filename for some reason. 1069** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1070** must invent its own temporary name for the file. ^Whenever the 1071** xFilename parameter is NULL it will also be the case that the 1072** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1073** 1074** The flags argument to xOpen() includes all bits set in 1075** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1076** or [sqlite3_open16()] is used, then flags includes at least 1077** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1078** If xOpen() opens a file read-only then it sets *pOutFlags to 1079** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1080** 1081** ^(SQLite will also add one of the following flags to the xOpen() 1082** call, depending on the object being opened: 1083** 1084** <ul> 1085** <li> [SQLITE_OPEN_MAIN_DB] 1086** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1087** <li> [SQLITE_OPEN_TEMP_DB] 1088** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1089** <li> [SQLITE_OPEN_TRANSIENT_DB] 1090** <li> [SQLITE_OPEN_SUBJOURNAL] 1091** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1092** <li> [SQLITE_OPEN_WAL] 1093** </ul>)^ 1094** 1095** The file I/O implementation can use the object type flags to 1096** change the way it deals with files. For example, an application 1097** that does not care about crash recovery or rollback might make 1098** the open of a journal file a no-op. Writes to this journal would 1099** also be no-ops, and any attempt to read the journal would return 1100** SQLITE_IOERR. Or the implementation might recognize that a database 1101** file will be doing page-aligned sector reads and writes in a random 1102** order and set up its I/O subsystem accordingly. 1103** 1104** SQLite might also add one of the following flags to the xOpen method: 1105** 1106** <ul> 1107** <li> [SQLITE_OPEN_DELETEONCLOSE] 1108** <li> [SQLITE_OPEN_EXCLUSIVE] 1109** </ul> 1110** 1111** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1112** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1113** will be set for TEMP databases and their journals, transient 1114** databases, and subjournals. 1115** 1116** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1117** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1118** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1119** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1120** SQLITE_OPEN_CREATE, is used to indicate that file should always 1121** be created, and that it is an error if it already exists. 1122** It is <i>not</i> used to indicate the file should be opened 1123** for exclusive access. 1124** 1125** ^At least szOsFile bytes of memory are allocated by SQLite 1126** to hold the [sqlite3_file] structure passed as the third 1127** argument to xOpen. The xOpen method does not have to 1128** allocate the structure; it should just fill it in. Note that 1129** the xOpen method must set the sqlite3_file.pMethods to either 1130** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1131** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1132** element will be valid after xOpen returns regardless of the success 1133** or failure of the xOpen call. 1134** 1135** [[sqlite3_vfs.xAccess]] 1136** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1137** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1138** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1139** to test whether a file is at least readable. The file can be a 1140** directory. 1141** 1142** ^SQLite will always allocate at least mxPathname+1 bytes for the 1143** output buffer xFullPathname. The exact size of the output buffer 1144** is also passed as a parameter to both methods. If the output buffer 1145** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1146** handled as a fatal error by SQLite, vfs implementations should endeavor 1147** to prevent this by setting mxPathname to a sufficiently large value. 1148** 1149** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1150** interfaces are not strictly a part of the filesystem, but they are 1151** included in the VFS structure for completeness. 1152** The xRandomness() function attempts to return nBytes bytes 1153** of good-quality randomness into zOut. The return value is 1154** the actual number of bytes of randomness obtained. 1155** The xSleep() method causes the calling thread to sleep for at 1156** least the number of microseconds given. ^The xCurrentTime() 1157** method returns a Julian Day Number for the current date and time as 1158** a floating point value. 1159** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1160** Day Number multiplied by 86400000 (the number of milliseconds in 1161** a 24-hour day). 1162** ^SQLite will use the xCurrentTimeInt64() method to get the current 1163** date and time if that method is available (if iVersion is 2 or 1164** greater and the function pointer is not NULL) and will fall back 1165** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1166** 1167** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1168** are not used by the SQLite core. These optional interfaces are provided 1169** by some VFSes to facilitate testing of the VFS code. By overriding 1170** system calls with functions under its control, a test program can 1171** simulate faults and error conditions that would otherwise be difficult 1172** or impossible to induce. The set of system calls that can be overridden 1173** varies from one VFS to another, and from one version of the same VFS to the 1174** next. Applications that use these interfaces must be prepared for any 1175** or all of these interfaces to be NULL or for their behavior to change 1176** from one release to the next. Applications must not attempt to access 1177** any of these methods if the iVersion of the VFS is less than 3. 1178*/ 1179typedef struct sqlite3_vfs sqlite3_vfs; 1180typedef void (*sqlite3_syscall_ptr)(void); 1181struct sqlite3_vfs { 1182 int iVersion; /* Structure version number (currently 3) */ 1183 int szOsFile; /* Size of subclassed sqlite3_file */ 1184 int mxPathname; /* Maximum file pathname length */ 1185 sqlite3_vfs *pNext; /* Next registered VFS */ 1186 const char *zName; /* Name of this virtual file system */ 1187 void *pAppData; /* Pointer to application-specific data */ 1188 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1189 int flags, int *pOutFlags); 1190 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1191 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1192 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1193 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1194 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1195 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1196 void (*xDlClose)(sqlite3_vfs*, void*); 1197 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1198 int (*xSleep)(sqlite3_vfs*, int microseconds); 1199 int (*xCurrentTime)(sqlite3_vfs*, double*); 1200 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1201 /* 1202 ** The methods above are in version 1 of the sqlite_vfs object 1203 ** definition. Those that follow are added in version 2 or later 1204 */ 1205 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1206 /* 1207 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1208 ** Those below are for version 3 and greater. 1209 */ 1210 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1211 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1212 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1213 /* 1214 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1215 ** New fields may be appended in figure versions. The iVersion 1216 ** value will increment whenever this happens. 1217 */ 1218}; 1219 1220/* 1221** CAPI3REF: Flags for the xAccess VFS method 1222** 1223** These integer constants can be used as the third parameter to 1224** the xAccess method of an [sqlite3_vfs] object. They determine 1225** what kind of permissions the xAccess method is looking for. 1226** With SQLITE_ACCESS_EXISTS, the xAccess method 1227** simply checks whether the file exists. 1228** With SQLITE_ACCESS_READWRITE, the xAccess method 1229** checks whether the named directory is both readable and writable 1230** (in other words, if files can be added, removed, and renamed within 1231** the directory). 1232** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1233** [temp_store_directory pragma], though this could change in a future 1234** release of SQLite. 1235** With SQLITE_ACCESS_READ, the xAccess method 1236** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1237** currently unused, though it might be used in a future release of 1238** SQLite. 1239*/ 1240#define SQLITE_ACCESS_EXISTS 0 1241#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1242#define SQLITE_ACCESS_READ 2 /* Unused */ 1243 1244/* 1245** CAPI3REF: Flags for the xShmLock VFS method 1246** 1247** These integer constants define the various locking operations 1248** allowed by the xShmLock method of [sqlite3_io_methods]. The 1249** following are the only legal combinations of flags to the 1250** xShmLock method: 1251** 1252** <ul> 1253** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1254** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1255** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1256** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1257** </ul> 1258** 1259** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1260** was given on the corresponding lock. 1261** 1262** The xShmLock method can transition between unlocked and SHARED or 1263** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1264** and EXCLUSIVE. 1265*/ 1266#define SQLITE_SHM_UNLOCK 1 1267#define SQLITE_SHM_LOCK 2 1268#define SQLITE_SHM_SHARED 4 1269#define SQLITE_SHM_EXCLUSIVE 8 1270 1271/* 1272** CAPI3REF: Maximum xShmLock index 1273** 1274** The xShmLock method on [sqlite3_io_methods] may use values 1275** between 0 and this upper bound as its "offset" argument. 1276** The SQLite core will never attempt to acquire or release a 1277** lock outside of this range 1278*/ 1279#define SQLITE_SHM_NLOCK 8 1280 1281 1282/* 1283** CAPI3REF: Initialize The SQLite Library 1284** 1285** ^The sqlite3_initialize() routine initializes the 1286** SQLite library. ^The sqlite3_shutdown() routine 1287** deallocates any resources that were allocated by sqlite3_initialize(). 1288** These routines are designed to aid in process initialization and 1289** shutdown on embedded systems. Workstation applications using 1290** SQLite normally do not need to invoke either of these routines. 1291** 1292** A call to sqlite3_initialize() is an "effective" call if it is 1293** the first time sqlite3_initialize() is invoked during the lifetime of 1294** the process, or if it is the first time sqlite3_initialize() is invoked 1295** following a call to sqlite3_shutdown(). ^(Only an effective call 1296** of sqlite3_initialize() does any initialization. All other calls 1297** are harmless no-ops.)^ 1298** 1299** A call to sqlite3_shutdown() is an "effective" call if it is the first 1300** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1301** an effective call to sqlite3_shutdown() does any deinitialization. 1302** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1303** 1304** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1305** is not. The sqlite3_shutdown() interface must only be called from a 1306** single thread. All open [database connections] must be closed and all 1307** other SQLite resources must be deallocated prior to invoking 1308** sqlite3_shutdown(). 1309** 1310** Among other things, ^sqlite3_initialize() will invoke 1311** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1312** will invoke sqlite3_os_end(). 1313** 1314** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1315** ^If for some reason, sqlite3_initialize() is unable to initialize 1316** the library (perhaps it is unable to allocate a needed resource such 1317** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1318** 1319** ^The sqlite3_initialize() routine is called internally by many other 1320** SQLite interfaces so that an application usually does not need to 1321** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1322** calls sqlite3_initialize() so the SQLite library will be automatically 1323** initialized when [sqlite3_open()] is called if it has not be initialized 1324** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1325** compile-time option, then the automatic calls to sqlite3_initialize() 1326** are omitted and the application must call sqlite3_initialize() directly 1327** prior to using any other SQLite interface. For maximum portability, 1328** it is recommended that applications always invoke sqlite3_initialize() 1329** directly prior to using any other SQLite interface. Future releases 1330** of SQLite may require this. In other words, the behavior exhibited 1331** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1332** default behavior in some future release of SQLite. 1333** 1334** The sqlite3_os_init() routine does operating-system specific 1335** initialization of the SQLite library. The sqlite3_os_end() 1336** routine undoes the effect of sqlite3_os_init(). Typical tasks 1337** performed by these routines include allocation or deallocation 1338** of static resources, initialization of global variables, 1339** setting up a default [sqlite3_vfs] module, or setting up 1340** a default configuration using [sqlite3_config()]. 1341** 1342** The application should never invoke either sqlite3_os_init() 1343** or sqlite3_os_end() directly. The application should only invoke 1344** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1345** interface is called automatically by sqlite3_initialize() and 1346** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1347** implementations for sqlite3_os_init() and sqlite3_os_end() 1348** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1349** When [custom builds | built for other platforms] 1350** (using the [SQLITE_OS_OTHER=1] compile-time 1351** option) the application must supply a suitable implementation for 1352** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1353** implementation of sqlite3_os_init() or sqlite3_os_end() 1354** must return [SQLITE_OK] on success and some other [error code] upon 1355** failure. 1356*/ 1357int sqlite3_initialize(void); 1358int sqlite3_shutdown(void); 1359int sqlite3_os_init(void); 1360int sqlite3_os_end(void); 1361 1362/* 1363** CAPI3REF: Configuring The SQLite Library 1364** 1365** The sqlite3_config() interface is used to make global configuration 1366** changes to SQLite in order to tune SQLite to the specific needs of 1367** the application. The default configuration is recommended for most 1368** applications and so this routine is usually not necessary. It is 1369** provided to support rare applications with unusual needs. 1370** 1371** <b>The sqlite3_config() interface is not threadsafe. The application 1372** must ensure that no other SQLite interfaces are invoked by other 1373** threads while sqlite3_config() is running.</b> 1374** 1375** The sqlite3_config() interface 1376** may only be invoked prior to library initialization using 1377** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1378** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1379** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1380** Note, however, that ^sqlite3_config() can be called as part of the 1381** implementation of an application-defined [sqlite3_os_init()]. 1382** 1383** The first argument to sqlite3_config() is an integer 1384** [configuration option] that determines 1385** what property of SQLite is to be configured. Subsequent arguments 1386** vary depending on the [configuration option] 1387** in the first argument. 1388** 1389** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1390** ^If the option is unknown or SQLite is unable to set the option 1391** then this routine returns a non-zero [error code]. 1392*/ 1393int sqlite3_config(int, ...); 1394 1395/* 1396** CAPI3REF: Configure database connections 1397** METHOD: sqlite3 1398** 1399** The sqlite3_db_config() interface is used to make configuration 1400** changes to a [database connection]. The interface is similar to 1401** [sqlite3_config()] except that the changes apply to a single 1402** [database connection] (specified in the first argument). 1403** 1404** The second argument to sqlite3_db_config(D,V,...) is the 1405** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1406** that indicates what aspect of the [database connection] is being configured. 1407** Subsequent arguments vary depending on the configuration verb. 1408** 1409** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1410** the call is considered successful. 1411*/ 1412int sqlite3_db_config(sqlite3*, int op, ...); 1413 1414/* 1415** CAPI3REF: Memory Allocation Routines 1416** 1417** An instance of this object defines the interface between SQLite 1418** and low-level memory allocation routines. 1419** 1420** This object is used in only one place in the SQLite interface. 1421** A pointer to an instance of this object is the argument to 1422** [sqlite3_config()] when the configuration option is 1423** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1424** By creating an instance of this object 1425** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1426** during configuration, an application can specify an alternative 1427** memory allocation subsystem for SQLite to use for all of its 1428** dynamic memory needs. 1429** 1430** Note that SQLite comes with several [built-in memory allocators] 1431** that are perfectly adequate for the overwhelming majority of applications 1432** and that this object is only useful to a tiny minority of applications 1433** with specialized memory allocation requirements. This object is 1434** also used during testing of SQLite in order to specify an alternative 1435** memory allocator that simulates memory out-of-memory conditions in 1436** order to verify that SQLite recovers gracefully from such 1437** conditions. 1438** 1439** The xMalloc, xRealloc, and xFree methods must work like the 1440** malloc(), realloc() and free() functions from the standard C library. 1441** ^SQLite guarantees that the second argument to 1442** xRealloc is always a value returned by a prior call to xRoundup. 1443** 1444** xSize should return the allocated size of a memory allocation 1445** previously obtained from xMalloc or xRealloc. The allocated size 1446** is always at least as big as the requested size but may be larger. 1447** 1448** The xRoundup method returns what would be the allocated size of 1449** a memory allocation given a particular requested size. Most memory 1450** allocators round up memory allocations at least to the next multiple 1451** of 8. Some allocators round up to a larger multiple or to a power of 2. 1452** Every memory allocation request coming in through [sqlite3_malloc()] 1453** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1454** that causes the corresponding memory allocation to fail. 1455** 1456** The xInit method initializes the memory allocator. For example, 1457** it might allocate any require mutexes or initialize internal data 1458** structures. The xShutdown method is invoked (indirectly) by 1459** [sqlite3_shutdown()] and should deallocate any resources acquired 1460** by xInit. The pAppData pointer is used as the only parameter to 1461** xInit and xShutdown. 1462** 1463** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1464** the xInit method, so the xInit method need not be threadsafe. The 1465** xShutdown method is only called from [sqlite3_shutdown()] so it does 1466** not need to be threadsafe either. For all other methods, SQLite 1467** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1468** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1469** it is by default) and so the methods are automatically serialized. 1470** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1471** methods must be threadsafe or else make their own arrangements for 1472** serialization. 1473** 1474** SQLite will never invoke xInit() more than once without an intervening 1475** call to xShutdown(). 1476*/ 1477typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1478struct sqlite3_mem_methods { 1479 void *(*xMalloc)(int); /* Memory allocation function */ 1480 void (*xFree)(void*); /* Free a prior allocation */ 1481 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1482 int (*xSize)(void*); /* Return the size of an allocation */ 1483 int (*xRoundup)(int); /* Round up request size to allocation size */ 1484 int (*xInit)(void*); /* Initialize the memory allocator */ 1485 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1486 void *pAppData; /* Argument to xInit() and xShutdown() */ 1487}; 1488 1489/* 1490** CAPI3REF: Configuration Options 1491** KEYWORDS: {configuration option} 1492** 1493** These constants are the available integer configuration options that 1494** can be passed as the first argument to the [sqlite3_config()] interface. 1495** 1496** New configuration options may be added in future releases of SQLite. 1497** Existing configuration options might be discontinued. Applications 1498** should check the return code from [sqlite3_config()] to make sure that 1499** the call worked. The [sqlite3_config()] interface will return a 1500** non-zero [error code] if a discontinued or unsupported configuration option 1501** is invoked. 1502** 1503** <dl> 1504** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1505** <dd>There are no arguments to this option. ^This option sets the 1506** [threading mode] to Single-thread. In other words, it disables 1507** all mutexing and puts SQLite into a mode where it can only be used 1508** by a single thread. ^If SQLite is compiled with 1509** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1510** it is not possible to change the [threading mode] from its default 1511** value of Single-thread and so [sqlite3_config()] will return 1512** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1513** configuration option.</dd> 1514** 1515** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1516** <dd>There are no arguments to this option. ^This option sets the 1517** [threading mode] to Multi-thread. In other words, it disables 1518** mutexing on [database connection] and [prepared statement] objects. 1519** The application is responsible for serializing access to 1520** [database connections] and [prepared statements]. But other mutexes 1521** are enabled so that SQLite will be safe to use in a multi-threaded 1522** environment as long as no two threads attempt to use the same 1523** [database connection] at the same time. ^If SQLite is compiled with 1524** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1525** it is not possible to set the Multi-thread [threading mode] and 1526** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1527** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1528** 1529** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1530** <dd>There are no arguments to this option. ^This option sets the 1531** [threading mode] to Serialized. In other words, this option enables 1532** all mutexes including the recursive 1533** mutexes on [database connection] and [prepared statement] objects. 1534** In this mode (which is the default when SQLite is compiled with 1535** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1536** to [database connections] and [prepared statements] so that the 1537** application is free to use the same [database connection] or the 1538** same [prepared statement] in different threads at the same time. 1539** ^If SQLite is compiled with 1540** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1541** it is not possible to set the Serialized [threading mode] and 1542** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1543** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1544** 1545** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1546** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1547** a pointer to an instance of the [sqlite3_mem_methods] structure. 1548** The argument specifies 1549** alternative low-level memory allocation routines to be used in place of 1550** the memory allocation routines built into SQLite.)^ ^SQLite makes 1551** its own private copy of the content of the [sqlite3_mem_methods] structure 1552** before the [sqlite3_config()] call returns.</dd> 1553** 1554** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1555** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1556** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1557** The [sqlite3_mem_methods] 1558** structure is filled with the currently defined memory allocation routines.)^ 1559** This option can be used to overload the default memory allocation 1560** routines with a wrapper that simulations memory allocation failure or 1561** tracks memory usage, for example. </dd> 1562** 1563** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1564** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1565** interpreted as a boolean, which enables or disables the collection of 1566** memory allocation statistics. ^(When memory allocation statistics are 1567** disabled, the following SQLite interfaces become non-operational: 1568** <ul> 1569** <li> [sqlite3_memory_used()] 1570** <li> [sqlite3_memory_highwater()] 1571** <li> [sqlite3_soft_heap_limit64()] 1572** <li> [sqlite3_status64()] 1573** </ul>)^ 1574** ^Memory allocation statistics are enabled by default unless SQLite is 1575** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1576** allocation statistics are disabled by default. 1577** </dd> 1578** 1579** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1580** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer 1581** that SQLite can use for scratch memory. ^(There are three arguments 1582** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte 1583** aligned memory buffer from which the scratch allocations will be 1584** drawn, the size of each scratch allocation (sz), 1585** and the maximum number of scratch allocations (N).)^ 1586** The first argument must be a pointer to an 8-byte aligned buffer 1587** of at least sz*N bytes of memory. 1588** ^SQLite will not use more than one scratch buffers per thread. 1589** ^SQLite will never request a scratch buffer that is more than 6 1590** times the database page size. 1591** ^If SQLite needs needs additional 1592** scratch memory beyond what is provided by this configuration option, then 1593** [sqlite3_malloc()] will be used to obtain the memory needed.<p> 1594** ^When the application provides any amount of scratch memory using 1595** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large 1596** [sqlite3_malloc|heap allocations]. 1597** This can help [Robson proof|prevent memory allocation failures] due to heap 1598** fragmentation in low-memory embedded systems. 1599** </dd> 1600** 1601** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1602** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer 1603** that SQLite can use for the database page cache with the default page 1604** cache implementation. 1605** This configuration should not be used if an application-define page 1606** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2] 1607** configuration option. 1608** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1609** 8-byte aligned 1610** memory, the size of each page buffer (sz), and the number of pages (N). 1611** The sz argument should be the size of the largest database page 1612** (a power of two between 512 and 65536) plus some extra bytes for each 1613** page header. ^The number of extra bytes needed by the page header 1614** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option 1615** to [sqlite3_config()]. 1616** ^It is harmless, apart from the wasted memory, 1617** for the sz parameter to be larger than necessary. The first 1618** argument should pointer to an 8-byte aligned block of memory that 1619** is at least sz*N bytes of memory, otherwise subsequent behavior is 1620** undefined. 1621** ^SQLite will use the memory provided by the first argument to satisfy its 1622** memory needs for the first N pages that it adds to cache. ^If additional 1623** page cache memory is needed beyond what is provided by this option, then 1624** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd> 1625** 1626** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1627** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1628** that SQLite will use for all of its dynamic memory allocation needs 1629** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and 1630** [SQLITE_CONFIG_PAGECACHE]. 1631** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1632** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1633** [SQLITE_ERROR] if invoked otherwise. 1634** ^There are three arguments to SQLITE_CONFIG_HEAP: 1635** An 8-byte aligned pointer to the memory, 1636** the number of bytes in the memory buffer, and the minimum allocation size. 1637** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1638** to using its default memory allocator (the system malloc() implementation), 1639** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1640** memory pointer is not NULL then the alternative memory 1641** allocator is engaged to handle all of SQLites memory allocation needs. 1642** The first pointer (the memory pointer) must be aligned to an 8-byte 1643** boundary or subsequent behavior of SQLite will be undefined. 1644** The minimum allocation size is capped at 2**12. Reasonable values 1645** for the minimum allocation size are 2**5 through 2**8.</dd> 1646** 1647** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1648** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1649** pointer to an instance of the [sqlite3_mutex_methods] structure. 1650** The argument specifies alternative low-level mutex routines to be used 1651** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1652** the content of the [sqlite3_mutex_methods] structure before the call to 1653** [sqlite3_config()] returns. ^If SQLite is compiled with 1654** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1655** the entire mutexing subsystem is omitted from the build and hence calls to 1656** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1657** return [SQLITE_ERROR].</dd> 1658** 1659** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1660** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1661** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1662** [sqlite3_mutex_methods] 1663** structure is filled with the currently defined mutex routines.)^ 1664** This option can be used to overload the default mutex allocation 1665** routines with a wrapper used to track mutex usage for performance 1666** profiling or testing, for example. ^If SQLite is compiled with 1667** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1668** the entire mutexing subsystem is omitted from the build and hence calls to 1669** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1670** return [SQLITE_ERROR].</dd> 1671** 1672** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1673** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1674** the default size of lookaside memory on each [database connection]. 1675** The first argument is the 1676** size of each lookaside buffer slot and the second is the number of 1677** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1678** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1679** option to [sqlite3_db_config()] can be used to change the lookaside 1680** configuration on individual connections.)^ </dd> 1681** 1682** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1683** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1684** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1685** the interface to a custom page cache implementation.)^ 1686** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1687** 1688** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1689** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1690** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1691** the current page cache implementation into that object.)^ </dd> 1692** 1693** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1694** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1695** global [error log]. 1696** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1697** function with a call signature of void(*)(void*,int,const char*), 1698** and a pointer to void. ^If the function pointer is not NULL, it is 1699** invoked by [sqlite3_log()] to process each logging event. ^If the 1700** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1701** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1702** passed through as the first parameter to the application-defined logger 1703** function whenever that function is invoked. ^The second parameter to 1704** the logger function is a copy of the first parameter to the corresponding 1705** [sqlite3_log()] call and is intended to be a [result code] or an 1706** [extended result code]. ^The third parameter passed to the logger is 1707** log message after formatting via [sqlite3_snprintf()]. 1708** The SQLite logging interface is not reentrant; the logger function 1709** supplied by the application must not invoke any SQLite interface. 1710** In a multi-threaded application, the application-defined logger 1711** function must be threadsafe. </dd> 1712** 1713** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1714** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1715** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1716** then URI handling is globally disabled.)^ ^If URI handling is globally 1717** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1718** [sqlite3_open16()] or 1719** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1720** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1721** connection is opened. ^If it is globally disabled, filenames are 1722** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1723** database connection is opened. ^(By default, URI handling is globally 1724** disabled. The default value may be changed by compiling with the 1725** [SQLITE_USE_URI] symbol defined.)^ 1726** 1727** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1728** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1729** argument which is interpreted as a boolean in order to enable or disable 1730** the use of covering indices for full table scans in the query optimizer. 1731** ^The default setting is determined 1732** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1733** if that compile-time option is omitted. 1734** The ability to disable the use of covering indices for full table scans 1735** is because some incorrectly coded legacy applications might malfunction 1736** when the optimization is enabled. Providing the ability to 1737** disable the optimization allows the older, buggy application code to work 1738** without change even with newer versions of SQLite. 1739** 1740** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1741** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1742** <dd> These options are obsolete and should not be used by new code. 1743** They are retained for backwards compatibility but are now no-ops. 1744** </dd> 1745** 1746** [[SQLITE_CONFIG_SQLLOG]] 1747** <dt>SQLITE_CONFIG_SQLLOG 1748** <dd>This option is only available if sqlite is compiled with the 1749** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1750** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1751** The second should be of type (void*). The callback is invoked by the library 1752** in three separate circumstances, identified by the value passed as the 1753** fourth parameter. If the fourth parameter is 0, then the database connection 1754** passed as the second argument has just been opened. The third argument 1755** points to a buffer containing the name of the main database file. If the 1756** fourth parameter is 1, then the SQL statement that the third parameter 1757** points to has just been executed. Or, if the fourth parameter is 2, then 1758** the connection being passed as the second parameter is being closed. The 1759** third parameter is passed NULL In this case. An example of using this 1760** configuration option can be seen in the "test_sqllog.c" source file in 1761** the canonical SQLite source tree.</dd> 1762** 1763** [[SQLITE_CONFIG_MMAP_SIZE]] 1764** <dt>SQLITE_CONFIG_MMAP_SIZE 1765** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1766** that are the default mmap size limit (the default setting for 1767** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1768** ^The default setting can be overridden by each database connection using 1769** either the [PRAGMA mmap_size] command, or by using the 1770** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1771** will be silently truncated if necessary so that it does not exceed the 1772** compile-time maximum mmap size set by the 1773** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1774** ^If either argument to this option is negative, then that argument is 1775** changed to its compile-time default. 1776** 1777** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1778** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1779** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1780** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1781** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1782** that specifies the maximum size of the created heap. 1783** 1784** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1785** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1786** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1787** is a pointer to an integer and writes into that integer the number of extra 1788** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1789** The amount of extra space required can change depending on the compiler, 1790** target platform, and SQLite version. 1791** 1792** [[SQLITE_CONFIG_PMASZ]] 1793** <dt>SQLITE_CONFIG_PMASZ 1794** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1795** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1796** sorter to that integer. The default minimum PMA Size is set by the 1797** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1798** to help with sort operations when multithreaded sorting 1799** is enabled (using the [PRAGMA threads] command) and the amount of content 1800** to be sorted exceeds the page size times the minimum of the 1801** [PRAGMA cache_size] setting and this value. 1802** </dl> 1803*/ 1804#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1805#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1806#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1807#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1808#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1809#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1810#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1811#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1812#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1813#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1814#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1815/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1816#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1817#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1818#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1819#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1820#define SQLITE_CONFIG_URI 17 /* int */ 1821#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1822#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1823#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1824#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1825#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1826#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1827#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1828#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1829 1830/* 1831** CAPI3REF: Database Connection Configuration Options 1832** 1833** These constants are the available integer configuration options that 1834** can be passed as the second argument to the [sqlite3_db_config()] interface. 1835** 1836** New configuration options may be added in future releases of SQLite. 1837** Existing configuration options might be discontinued. Applications 1838** should check the return code from [sqlite3_db_config()] to make sure that 1839** the call worked. ^The [sqlite3_db_config()] interface will return a 1840** non-zero [error code] if a discontinued or unsupported configuration option 1841** is invoked. 1842** 1843** <dl> 1844** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1845** <dd> ^This option takes three additional arguments that determine the 1846** [lookaside memory allocator] configuration for the [database connection]. 1847** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1848** pointer to a memory buffer to use for lookaside memory. 1849** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1850** may be NULL in which case SQLite will allocate the 1851** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1852** size of each lookaside buffer slot. ^The third argument is the number of 1853** slots. The size of the buffer in the first argument must be greater than 1854** or equal to the product of the second and third arguments. The buffer 1855** must be aligned to an 8-byte boundary. ^If the second argument to 1856** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1857** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1858** configuration for a database connection can only be changed when that 1859** connection is not currently using lookaside memory, or in other words 1860** when the "current value" returned by 1861** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1862** Any attempt to change the lookaside memory configuration when lookaside 1863** memory is in use leaves the configuration unchanged and returns 1864** [SQLITE_BUSY].)^</dd> 1865** 1866** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1867** <dd> ^This option is used to enable or disable the enforcement of 1868** [foreign key constraints]. There should be two additional arguments. 1869** The first argument is an integer which is 0 to disable FK enforcement, 1870** positive to enable FK enforcement or negative to leave FK enforcement 1871** unchanged. The second parameter is a pointer to an integer into which 1872** is written 0 or 1 to indicate whether FK enforcement is off or on 1873** following this call. The second parameter may be a NULL pointer, in 1874** which case the FK enforcement setting is not reported back. </dd> 1875** 1876** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1877** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1878** There should be two additional arguments. 1879** The first argument is an integer which is 0 to disable triggers, 1880** positive to enable triggers or negative to leave the setting unchanged. 1881** The second parameter is a pointer to an integer into which 1882** is written 0 or 1 to indicate whether triggers are disabled or enabled 1883** following this call. The second parameter may be a NULL pointer, in 1884** which case the trigger setting is not reported back. </dd> 1885** 1886** </dl> 1887*/ 1888#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1889#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1890#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1891 1892 1893/* 1894** CAPI3REF: Enable Or Disable Extended Result Codes 1895** METHOD: sqlite3 1896** 1897** ^The sqlite3_extended_result_codes() routine enables or disables the 1898** [extended result codes] feature of SQLite. ^The extended result 1899** codes are disabled by default for historical compatibility. 1900*/ 1901int sqlite3_extended_result_codes(sqlite3*, int onoff); 1902 1903/* 1904** CAPI3REF: Last Insert Rowid 1905** METHOD: sqlite3 1906** 1907** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 1908** has a unique 64-bit signed 1909** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1910** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1911** names are not also used by explicitly declared columns. ^If 1912** the table has a column of type [INTEGER PRIMARY KEY] then that column 1913** is another alias for the rowid. 1914** 1915** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the 1916** most recent successful [INSERT] into a rowid table or [virtual table] 1917** on database connection D. 1918** ^Inserts into [WITHOUT ROWID] tables are not recorded. 1919** ^If no successful [INSERT]s into rowid tables 1920** have ever occurred on the database connection D, 1921** then sqlite3_last_insert_rowid(D) returns zero. 1922** 1923** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1924** method, then this routine will return the [rowid] of the inserted 1925** row as long as the trigger or virtual table method is running. 1926** But once the trigger or virtual table method ends, the value returned 1927** by this routine reverts to what it was before the trigger or virtual 1928** table method began.)^ 1929** 1930** ^An [INSERT] that fails due to a constraint violation is not a 1931** successful [INSERT] and does not change the value returned by this 1932** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1933** and INSERT OR ABORT make no changes to the return value of this 1934** routine when their insertion fails. ^(When INSERT OR REPLACE 1935** encounters a constraint violation, it does not fail. The 1936** INSERT continues to completion after deleting rows that caused 1937** the constraint problem so INSERT OR REPLACE will always change 1938** the return value of this interface.)^ 1939** 1940** ^For the purposes of this routine, an [INSERT] is considered to 1941** be successful even if it is subsequently rolled back. 1942** 1943** This function is accessible to SQL statements via the 1944** [last_insert_rowid() SQL function]. 1945** 1946** If a separate thread performs a new [INSERT] on the same 1947** database connection while the [sqlite3_last_insert_rowid()] 1948** function is running and thus changes the last insert [rowid], 1949** then the value returned by [sqlite3_last_insert_rowid()] is 1950** unpredictable and might not equal either the old or the new 1951** last insert [rowid]. 1952*/ 1953sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1954 1955/* 1956** CAPI3REF: Count The Number Of Rows Modified 1957** METHOD: sqlite3 1958** 1959** ^This function returns the number of rows modified, inserted or 1960** deleted by the most recently completed INSERT, UPDATE or DELETE 1961** statement on the database connection specified by the only parameter. 1962** ^Executing any other type of SQL statement does not modify the value 1963** returned by this function. 1964** 1965** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 1966** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 1967** [foreign key actions] or [REPLACE] constraint resolution are not counted. 1968** 1969** Changes to a view that are intercepted by 1970** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 1971** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 1972** DELETE statement run on a view is always zero. Only changes made to real 1973** tables are counted. 1974** 1975** Things are more complicated if the sqlite3_changes() function is 1976** executed while a trigger program is running. This may happen if the 1977** program uses the [changes() SQL function], or if some other callback 1978** function invokes sqlite3_changes() directly. Essentially: 1979** 1980** <ul> 1981** <li> ^(Before entering a trigger program the value returned by 1982** sqlite3_changes() function is saved. After the trigger program 1983** has finished, the original value is restored.)^ 1984** 1985** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 1986** statement sets the value returned by sqlite3_changes() 1987** upon completion as normal. Of course, this value will not include 1988** any changes performed by sub-triggers, as the sqlite3_changes() 1989** value will be saved and restored after each sub-trigger has run.)^ 1990** </ul> 1991** 1992** ^This means that if the changes() SQL function (or similar) is used 1993** by the first INSERT, UPDATE or DELETE statement within a trigger, it 1994** returns the value as set when the calling statement began executing. 1995** ^If it is used by the second or subsequent such statement within a trigger 1996** program, the value returned reflects the number of rows modified by the 1997** previous INSERT, UPDATE or DELETE statement within the same trigger. 1998** 1999** See also the [sqlite3_total_changes()] interface, the 2000** [count_changes pragma], and the [changes() SQL function]. 2001** 2002** If a separate thread makes changes on the same database connection 2003** while [sqlite3_changes()] is running then the value returned 2004** is unpredictable and not meaningful. 2005*/ 2006int sqlite3_changes(sqlite3*); 2007 2008/* 2009** CAPI3REF: Total Number Of Rows Modified 2010** METHOD: sqlite3 2011** 2012** ^This function returns the total number of rows inserted, modified or 2013** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2014** since the database connection was opened, including those executed as 2015** part of trigger programs. ^Executing any other type of SQL statement 2016** does not affect the value returned by sqlite3_total_changes(). 2017** 2018** ^Changes made as part of [foreign key actions] are included in the 2019** count, but those made as part of REPLACE constraint resolution are 2020** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2021** are not counted. 2022** 2023** See also the [sqlite3_changes()] interface, the 2024** [count_changes pragma], and the [total_changes() SQL function]. 2025** 2026** If a separate thread makes changes on the same database connection 2027** while [sqlite3_total_changes()] is running then the value 2028** returned is unpredictable and not meaningful. 2029*/ 2030int sqlite3_total_changes(sqlite3*); 2031 2032/* 2033** CAPI3REF: Interrupt A Long-Running Query 2034** METHOD: sqlite3 2035** 2036** ^This function causes any pending database operation to abort and 2037** return at its earliest opportunity. This routine is typically 2038** called in response to a user action such as pressing "Cancel" 2039** or Ctrl-C where the user wants a long query operation to halt 2040** immediately. 2041** 2042** ^It is safe to call this routine from a thread different from the 2043** thread that is currently running the database operation. But it 2044** is not safe to call this routine with a [database connection] that 2045** is closed or might close before sqlite3_interrupt() returns. 2046** 2047** ^If an SQL operation is very nearly finished at the time when 2048** sqlite3_interrupt() is called, then it might not have an opportunity 2049** to be interrupted and might continue to completion. 2050** 2051** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2052** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2053** that is inside an explicit transaction, then the entire transaction 2054** will be rolled back automatically. 2055** 2056** ^The sqlite3_interrupt(D) call is in effect until all currently running 2057** SQL statements on [database connection] D complete. ^Any new SQL statements 2058** that are started after the sqlite3_interrupt() call and before the 2059** running statements reaches zero are interrupted as if they had been 2060** running prior to the sqlite3_interrupt() call. ^New SQL statements 2061** that are started after the running statement count reaches zero are 2062** not effected by the sqlite3_interrupt(). 2063** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2064** SQL statements is a no-op and has no effect on SQL statements 2065** that are started after the sqlite3_interrupt() call returns. 2066** 2067** If the database connection closes while [sqlite3_interrupt()] 2068** is running then bad things will likely happen. 2069*/ 2070void sqlite3_interrupt(sqlite3*); 2071 2072/* 2073** CAPI3REF: Determine If An SQL Statement Is Complete 2074** 2075** These routines are useful during command-line input to determine if the 2076** currently entered text seems to form a complete SQL statement or 2077** if additional input is needed before sending the text into 2078** SQLite for parsing. ^These routines return 1 if the input string 2079** appears to be a complete SQL statement. ^A statement is judged to be 2080** complete if it ends with a semicolon token and is not a prefix of a 2081** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2082** string literals or quoted identifier names or comments are not 2083** independent tokens (they are part of the token in which they are 2084** embedded) and thus do not count as a statement terminator. ^Whitespace 2085** and comments that follow the final semicolon are ignored. 2086** 2087** ^These routines return 0 if the statement is incomplete. ^If a 2088** memory allocation fails, then SQLITE_NOMEM is returned. 2089** 2090** ^These routines do not parse the SQL statements thus 2091** will not detect syntactically incorrect SQL. 2092** 2093** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2094** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2095** automatically by sqlite3_complete16(). If that initialization fails, 2096** then the return value from sqlite3_complete16() will be non-zero 2097** regardless of whether or not the input SQL is complete.)^ 2098** 2099** The input to [sqlite3_complete()] must be a zero-terminated 2100** UTF-8 string. 2101** 2102** The input to [sqlite3_complete16()] must be a zero-terminated 2103** UTF-16 string in native byte order. 2104*/ 2105int sqlite3_complete(const char *sql); 2106int sqlite3_complete16(const void *sql); 2107 2108/* 2109** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2110** KEYWORDS: {busy-handler callback} {busy handler} 2111** METHOD: sqlite3 2112** 2113** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2114** that might be invoked with argument P whenever 2115** an attempt is made to access a database table associated with 2116** [database connection] D when another thread 2117** or process has the table locked. 2118** The sqlite3_busy_handler() interface is used to implement 2119** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2120** 2121** ^If the busy callback is NULL, then [SQLITE_BUSY] 2122** is returned immediately upon encountering the lock. ^If the busy callback 2123** is not NULL, then the callback might be invoked with two arguments. 2124** 2125** ^The first argument to the busy handler is a copy of the void* pointer which 2126** is the third argument to sqlite3_busy_handler(). ^The second argument to 2127** the busy handler callback is the number of times that the busy handler has 2128** been invoked previously for the same locking event. ^If the 2129** busy callback returns 0, then no additional attempts are made to 2130** access the database and [SQLITE_BUSY] is returned 2131** to the application. 2132** ^If the callback returns non-zero, then another attempt 2133** is made to access the database and the cycle repeats. 2134** 2135** The presence of a busy handler does not guarantee that it will be invoked 2136** when there is lock contention. ^If SQLite determines that invoking the busy 2137** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2138** to the application instead of invoking the 2139** busy handler. 2140** Consider a scenario where one process is holding a read lock that 2141** it is trying to promote to a reserved lock and 2142** a second process is holding a reserved lock that it is trying 2143** to promote to an exclusive lock. The first process cannot proceed 2144** because it is blocked by the second and the second process cannot 2145** proceed because it is blocked by the first. If both processes 2146** invoke the busy handlers, neither will make any progress. Therefore, 2147** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2148** will induce the first process to release its read lock and allow 2149** the second process to proceed. 2150** 2151** ^The default busy callback is NULL. 2152** 2153** ^(There can only be a single busy handler defined for each 2154** [database connection]. Setting a new busy handler clears any 2155** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2156** or evaluating [PRAGMA busy_timeout=N] will change the 2157** busy handler and thus clear any previously set busy handler. 2158** 2159** The busy callback should not take any actions which modify the 2160** database connection that invoked the busy handler. In other words, 2161** the busy handler is not reentrant. Any such actions 2162** result in undefined behavior. 2163** 2164** A busy handler must not close the database connection 2165** or [prepared statement] that invoked the busy handler. 2166*/ 2167int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2168 2169/* 2170** CAPI3REF: Set A Busy Timeout 2171** METHOD: sqlite3 2172** 2173** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2174** for a specified amount of time when a table is locked. ^The handler 2175** will sleep multiple times until at least "ms" milliseconds of sleeping 2176** have accumulated. ^After at least "ms" milliseconds of sleeping, 2177** the handler returns 0 which causes [sqlite3_step()] to return 2178** [SQLITE_BUSY]. 2179** 2180** ^Calling this routine with an argument less than or equal to zero 2181** turns off all busy handlers. 2182** 2183** ^(There can only be a single busy handler for a particular 2184** [database connection] at any given moment. If another busy handler 2185** was defined (using [sqlite3_busy_handler()]) prior to calling 2186** this routine, that other busy handler is cleared.)^ 2187** 2188** See also: [PRAGMA busy_timeout] 2189*/ 2190int sqlite3_busy_timeout(sqlite3*, int ms); 2191 2192/* 2193** CAPI3REF: Convenience Routines For Running Queries 2194** METHOD: sqlite3 2195** 2196** This is a legacy interface that is preserved for backwards compatibility. 2197** Use of this interface is not recommended. 2198** 2199** Definition: A <b>result table</b> is memory data structure created by the 2200** [sqlite3_get_table()] interface. A result table records the 2201** complete query results from one or more queries. 2202** 2203** The table conceptually has a number of rows and columns. But 2204** these numbers are not part of the result table itself. These 2205** numbers are obtained separately. Let N be the number of rows 2206** and M be the number of columns. 2207** 2208** A result table is an array of pointers to zero-terminated UTF-8 strings. 2209** There are (N+1)*M elements in the array. The first M pointers point 2210** to zero-terminated strings that contain the names of the columns. 2211** The remaining entries all point to query results. NULL values result 2212** in NULL pointers. All other values are in their UTF-8 zero-terminated 2213** string representation as returned by [sqlite3_column_text()]. 2214** 2215** A result table might consist of one or more memory allocations. 2216** It is not safe to pass a result table directly to [sqlite3_free()]. 2217** A result table should be deallocated using [sqlite3_free_table()]. 2218** 2219** ^(As an example of the result table format, suppose a query result 2220** is as follows: 2221** 2222** <blockquote><pre> 2223** Name | Age 2224** ----------------------- 2225** Alice | 43 2226** Bob | 28 2227** Cindy | 21 2228** </pre></blockquote> 2229** 2230** There are two column (M==2) and three rows (N==3). Thus the 2231** result table has 8 entries. Suppose the result table is stored 2232** in an array names azResult. Then azResult holds this content: 2233** 2234** <blockquote><pre> 2235** azResult[0] = "Name"; 2236** azResult[1] = "Age"; 2237** azResult[2] = "Alice"; 2238** azResult[3] = "43"; 2239** azResult[4] = "Bob"; 2240** azResult[5] = "28"; 2241** azResult[6] = "Cindy"; 2242** azResult[7] = "21"; 2243** </pre></blockquote>)^ 2244** 2245** ^The sqlite3_get_table() function evaluates one or more 2246** semicolon-separated SQL statements in the zero-terminated UTF-8 2247** string of its 2nd parameter and returns a result table to the 2248** pointer given in its 3rd parameter. 2249** 2250** After the application has finished with the result from sqlite3_get_table(), 2251** it must pass the result table pointer to sqlite3_free_table() in order to 2252** release the memory that was malloced. Because of the way the 2253** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2254** function must not try to call [sqlite3_free()] directly. Only 2255** [sqlite3_free_table()] is able to release the memory properly and safely. 2256** 2257** The sqlite3_get_table() interface is implemented as a wrapper around 2258** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2259** to any internal data structures of SQLite. It uses only the public 2260** interface defined here. As a consequence, errors that occur in the 2261** wrapper layer outside of the internal [sqlite3_exec()] call are not 2262** reflected in subsequent calls to [sqlite3_errcode()] or 2263** [sqlite3_errmsg()]. 2264*/ 2265int sqlite3_get_table( 2266 sqlite3 *db, /* An open database */ 2267 const char *zSql, /* SQL to be evaluated */ 2268 char ***pazResult, /* Results of the query */ 2269 int *pnRow, /* Number of result rows written here */ 2270 int *pnColumn, /* Number of result columns written here */ 2271 char **pzErrmsg /* Error msg written here */ 2272); 2273void sqlite3_free_table(char **result); 2274 2275/* 2276** CAPI3REF: Formatted String Printing Functions 2277** 2278** These routines are work-alikes of the "printf()" family of functions 2279** from the standard C library. 2280** These routines understand most of the common K&R formatting options, 2281** plus some additional non-standard formats, detailed below. 2282** Note that some of the more obscure formatting options from recent 2283** C-library standards are omitted from this implementation. 2284** 2285** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2286** results into memory obtained from [sqlite3_malloc()]. 2287** The strings returned by these two routines should be 2288** released by [sqlite3_free()]. ^Both routines return a 2289** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2290** memory to hold the resulting string. 2291** 2292** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2293** the standard C library. The result is written into the 2294** buffer supplied as the second parameter whose size is given by 2295** the first parameter. Note that the order of the 2296** first two parameters is reversed from snprintf().)^ This is an 2297** historical accident that cannot be fixed without breaking 2298** backwards compatibility. ^(Note also that sqlite3_snprintf() 2299** returns a pointer to its buffer instead of the number of 2300** characters actually written into the buffer.)^ We admit that 2301** the number of characters written would be a more useful return 2302** value but we cannot change the implementation of sqlite3_snprintf() 2303** now without breaking compatibility. 2304** 2305** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2306** guarantees that the buffer is always zero-terminated. ^The first 2307** parameter "n" is the total size of the buffer, including space for 2308** the zero terminator. So the longest string that can be completely 2309** written will be n-1 characters. 2310** 2311** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2312** 2313** These routines all implement some additional formatting 2314** options that are useful for constructing SQL statements. 2315** All of the usual printf() formatting options apply. In addition, there 2316** is are "%q", "%Q", "%w" and "%z" options. 2317** 2318** ^(The %q option works like %s in that it substitutes a nul-terminated 2319** string from the argument list. But %q also doubles every '\'' character. 2320** %q is designed for use inside a string literal.)^ By doubling each '\'' 2321** character it escapes that character and allows it to be inserted into 2322** the string. 2323** 2324** For example, assume the string variable zText contains text as follows: 2325** 2326** <blockquote><pre> 2327** char *zText = "It's a happy day!"; 2328** </pre></blockquote> 2329** 2330** One can use this text in an SQL statement as follows: 2331** 2332** <blockquote><pre> 2333** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2334** sqlite3_exec(db, zSQL, 0, 0, 0); 2335** sqlite3_free(zSQL); 2336** </pre></blockquote> 2337** 2338** Because the %q format string is used, the '\'' character in zText 2339** is escaped and the SQL generated is as follows: 2340** 2341** <blockquote><pre> 2342** INSERT INTO table1 VALUES('It''s a happy day!') 2343** </pre></blockquote> 2344** 2345** This is correct. Had we used %s instead of %q, the generated SQL 2346** would have looked like this: 2347** 2348** <blockquote><pre> 2349** INSERT INTO table1 VALUES('It's a happy day!'); 2350** </pre></blockquote> 2351** 2352** This second example is an SQL syntax error. As a general rule you should 2353** always use %q instead of %s when inserting text into a string literal. 2354** 2355** ^(The %Q option works like %q except it also adds single quotes around 2356** the outside of the total string. Additionally, if the parameter in the 2357** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2358** single quotes).)^ So, for example, one could say: 2359** 2360** <blockquote><pre> 2361** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2362** sqlite3_exec(db, zSQL, 0, 0, 0); 2363** sqlite3_free(zSQL); 2364** </pre></blockquote> 2365** 2366** The code above will render a correct SQL statement in the zSQL 2367** variable even if the zText variable is a NULL pointer. 2368** 2369** ^(The "%w" formatting option is like "%q" except that it expects to 2370** be contained within double-quotes instead of single quotes, and it 2371** escapes the double-quote character instead of the single-quote 2372** character.)^ The "%w" formatting option is intended for safely inserting 2373** table and column names into a constructed SQL statement. 2374** 2375** ^(The "%z" formatting option works like "%s" but with the 2376** addition that after the string has been read and copied into 2377** the result, [sqlite3_free()] is called on the input string.)^ 2378*/ 2379char *sqlite3_mprintf(const char*,...); 2380char *sqlite3_vmprintf(const char*, va_list); 2381char *sqlite3_snprintf(int,char*,const char*, ...); 2382char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2383 2384/* 2385** CAPI3REF: Memory Allocation Subsystem 2386** 2387** The SQLite core uses these three routines for all of its own 2388** internal memory allocation needs. "Core" in the previous sentence 2389** does not include operating-system specific VFS implementation. The 2390** Windows VFS uses native malloc() and free() for some operations. 2391** 2392** ^The sqlite3_malloc() routine returns a pointer to a block 2393** of memory at least N bytes in length, where N is the parameter. 2394** ^If sqlite3_malloc() is unable to obtain sufficient free 2395** memory, it returns a NULL pointer. ^If the parameter N to 2396** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2397** a NULL pointer. 2398** 2399** ^The sqlite3_malloc64(N) routine works just like 2400** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2401** of a signed 32-bit integer. 2402** 2403** ^Calling sqlite3_free() with a pointer previously returned 2404** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2405** that it might be reused. ^The sqlite3_free() routine is 2406** a no-op if is called with a NULL pointer. Passing a NULL pointer 2407** to sqlite3_free() is harmless. After being freed, memory 2408** should neither be read nor written. Even reading previously freed 2409** memory might result in a segmentation fault or other severe error. 2410** Memory corruption, a segmentation fault, or other severe error 2411** might result if sqlite3_free() is called with a non-NULL pointer that 2412** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2413** 2414** ^The sqlite3_realloc(X,N) interface attempts to resize a 2415** prior memory allocation X to be at least N bytes. 2416** ^If the X parameter to sqlite3_realloc(X,N) 2417** is a NULL pointer then its behavior is identical to calling 2418** sqlite3_malloc(N). 2419** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2420** negative then the behavior is exactly the same as calling 2421** sqlite3_free(X). 2422** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2423** of at least N bytes in size or NULL if insufficient memory is available. 2424** ^If M is the size of the prior allocation, then min(N,M) bytes 2425** of the prior allocation are copied into the beginning of buffer returned 2426** by sqlite3_realloc(X,N) and the prior allocation is freed. 2427** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2428** prior allocation is not freed. 2429** 2430** ^The sqlite3_realloc64(X,N) interfaces works the same as 2431** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2432** of a 32-bit signed integer. 2433** 2434** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2435** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2436** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2437** ^The value returned by sqlite3_msize(X) might be larger than the number 2438** of bytes requested when X was allocated. ^If X is a NULL pointer then 2439** sqlite3_msize(X) returns zero. If X points to something that is not 2440** the beginning of memory allocation, or if it points to a formerly 2441** valid memory allocation that has now been freed, then the behavior 2442** of sqlite3_msize(X) is undefined and possibly harmful. 2443** 2444** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2445** sqlite3_malloc64(), and sqlite3_realloc64() 2446** is always aligned to at least an 8 byte boundary, or to a 2447** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2448** option is used. 2449** 2450** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2451** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2452** implementation of these routines to be omitted. That capability 2453** is no longer provided. Only built-in memory allocators can be used. 2454** 2455** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2456** the system malloc() and free() directly when converting 2457** filenames between the UTF-8 encoding used by SQLite 2458** and whatever filename encoding is used by the particular Windows 2459** installation. Memory allocation errors were detected, but 2460** they were reported back as [SQLITE_CANTOPEN] or 2461** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2462** 2463** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2464** must be either NULL or else pointers obtained from a prior 2465** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2466** not yet been released. 2467** 2468** The application must not read or write any part of 2469** a block of memory after it has been released using 2470** [sqlite3_free()] or [sqlite3_realloc()]. 2471*/ 2472void *sqlite3_malloc(int); 2473void *sqlite3_malloc64(sqlite3_uint64); 2474void *sqlite3_realloc(void*, int); 2475void *sqlite3_realloc64(void*, sqlite3_uint64); 2476void sqlite3_free(void*); 2477sqlite3_uint64 sqlite3_msize(void*); 2478 2479/* 2480** CAPI3REF: Memory Allocator Statistics 2481** 2482** SQLite provides these two interfaces for reporting on the status 2483** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2484** routines, which form the built-in memory allocation subsystem. 2485** 2486** ^The [sqlite3_memory_used()] routine returns the number of bytes 2487** of memory currently outstanding (malloced but not freed). 2488** ^The [sqlite3_memory_highwater()] routine returns the maximum 2489** value of [sqlite3_memory_used()] since the high-water mark 2490** was last reset. ^The values returned by [sqlite3_memory_used()] and 2491** [sqlite3_memory_highwater()] include any overhead 2492** added by SQLite in its implementation of [sqlite3_malloc()], 2493** but not overhead added by the any underlying system library 2494** routines that [sqlite3_malloc()] may call. 2495** 2496** ^The memory high-water mark is reset to the current value of 2497** [sqlite3_memory_used()] if and only if the parameter to 2498** [sqlite3_memory_highwater()] is true. ^The value returned 2499** by [sqlite3_memory_highwater(1)] is the high-water mark 2500** prior to the reset. 2501*/ 2502sqlite3_int64 sqlite3_memory_used(void); 2503sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2504 2505/* 2506** CAPI3REF: Pseudo-Random Number Generator 2507** 2508** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2509** select random [ROWID | ROWIDs] when inserting new records into a table that 2510** already uses the largest possible [ROWID]. The PRNG is also used for 2511** the build-in random() and randomblob() SQL functions. This interface allows 2512** applications to access the same PRNG for other purposes. 2513** 2514** ^A call to this routine stores N bytes of randomness into buffer P. 2515** ^The P parameter can be a NULL pointer. 2516** 2517** ^If this routine has not been previously called or if the previous 2518** call had N less than one or a NULL pointer for P, then the PRNG is 2519** seeded using randomness obtained from the xRandomness method of 2520** the default [sqlite3_vfs] object. 2521** ^If the previous call to this routine had an N of 1 or more and a 2522** non-NULL P then the pseudo-randomness is generated 2523** internally and without recourse to the [sqlite3_vfs] xRandomness 2524** method. 2525*/ 2526void sqlite3_randomness(int N, void *P); 2527 2528/* 2529** CAPI3REF: Compile-Time Authorization Callbacks 2530** METHOD: sqlite3 2531** 2532** ^This routine registers an authorizer callback with a particular 2533** [database connection], supplied in the first argument. 2534** ^The authorizer callback is invoked as SQL statements are being compiled 2535** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2536** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2537** points during the compilation process, as logic is being created 2538** to perform various actions, the authorizer callback is invoked to 2539** see if those actions are allowed. ^The authorizer callback should 2540** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2541** specific action but allow the SQL statement to continue to be 2542** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2543** rejected with an error. ^If the authorizer callback returns 2544** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2545** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2546** the authorizer will fail with an error message. 2547** 2548** When the callback returns [SQLITE_OK], that means the operation 2549** requested is ok. ^When the callback returns [SQLITE_DENY], the 2550** [sqlite3_prepare_v2()] or equivalent call that triggered the 2551** authorizer will fail with an error message explaining that 2552** access is denied. 2553** 2554** ^The first parameter to the authorizer callback is a copy of the third 2555** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2556** to the callback is an integer [SQLITE_COPY | action code] that specifies 2557** the particular action to be authorized. ^The third through sixth parameters 2558** to the callback are zero-terminated strings that contain additional 2559** details about the action to be authorized. 2560** 2561** ^If the action code is [SQLITE_READ] 2562** and the callback returns [SQLITE_IGNORE] then the 2563** [prepared statement] statement is constructed to substitute 2564** a NULL value in place of the table column that would have 2565** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2566** return can be used to deny an untrusted user access to individual 2567** columns of a table. 2568** ^If the action code is [SQLITE_DELETE] and the callback returns 2569** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2570** [truncate optimization] is disabled and all rows are deleted individually. 2571** 2572** An authorizer is used when [sqlite3_prepare | preparing] 2573** SQL statements from an untrusted source, to ensure that the SQL statements 2574** do not try to access data they are not allowed to see, or that they do not 2575** try to execute malicious statements that damage the database. For 2576** example, an application may allow a user to enter arbitrary 2577** SQL queries for evaluation by a database. But the application does 2578** not want the user to be able to make arbitrary changes to the 2579** database. An authorizer could then be put in place while the 2580** user-entered SQL is being [sqlite3_prepare | prepared] that 2581** disallows everything except [SELECT] statements. 2582** 2583** Applications that need to process SQL from untrusted sources 2584** might also consider lowering resource limits using [sqlite3_limit()] 2585** and limiting database size using the [max_page_count] [PRAGMA] 2586** in addition to using an authorizer. 2587** 2588** ^(Only a single authorizer can be in place on a database connection 2589** at a time. Each call to sqlite3_set_authorizer overrides the 2590** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2591** The authorizer is disabled by default. 2592** 2593** The authorizer callback must not do anything that will modify 2594** the database connection that invoked the authorizer callback. 2595** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2596** database connections for the meaning of "modify" in this paragraph. 2597** 2598** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2599** statement might be re-prepared during [sqlite3_step()] due to a 2600** schema change. Hence, the application should ensure that the 2601** correct authorizer callback remains in place during the [sqlite3_step()]. 2602** 2603** ^Note that the authorizer callback is invoked only during 2604** [sqlite3_prepare()] or its variants. Authorization is not 2605** performed during statement evaluation in [sqlite3_step()], unless 2606** as stated in the previous paragraph, sqlite3_step() invokes 2607** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2608*/ 2609int sqlite3_set_authorizer( 2610 sqlite3*, 2611 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2612 void *pUserData 2613); 2614 2615/* 2616** CAPI3REF: Authorizer Return Codes 2617** 2618** The [sqlite3_set_authorizer | authorizer callback function] must 2619** return either [SQLITE_OK] or one of these two constants in order 2620** to signal SQLite whether or not the action is permitted. See the 2621** [sqlite3_set_authorizer | authorizer documentation] for additional 2622** information. 2623** 2624** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2625** returned from the [sqlite3_vtab_on_conflict()] interface. 2626*/ 2627#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2628#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2629 2630/* 2631** CAPI3REF: Authorizer Action Codes 2632** 2633** The [sqlite3_set_authorizer()] interface registers a callback function 2634** that is invoked to authorize certain SQL statement actions. The 2635** second parameter to the callback is an integer code that specifies 2636** what action is being authorized. These are the integer action codes that 2637** the authorizer callback may be passed. 2638** 2639** These action code values signify what kind of operation is to be 2640** authorized. The 3rd and 4th parameters to the authorization 2641** callback function will be parameters or NULL depending on which of these 2642** codes is used as the second parameter. ^(The 5th parameter to the 2643** authorizer callback is the name of the database ("main", "temp", 2644** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2645** is the name of the inner-most trigger or view that is responsible for 2646** the access attempt or NULL if this access attempt is directly from 2647** top-level SQL code. 2648*/ 2649/******************************************* 3rd ************ 4th ***********/ 2650#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2651#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2652#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2653#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2654#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2655#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2656#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2657#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2658#define SQLITE_DELETE 9 /* Table Name NULL */ 2659#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2660#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2661#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2662#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2663#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2664#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2665#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2666#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2667#define SQLITE_INSERT 18 /* Table Name NULL */ 2668#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2669#define SQLITE_READ 20 /* Table Name Column Name */ 2670#define SQLITE_SELECT 21 /* NULL NULL */ 2671#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2672#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2673#define SQLITE_ATTACH 24 /* Filename NULL */ 2674#define SQLITE_DETACH 25 /* Database Name NULL */ 2675#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2676#define SQLITE_REINDEX 27 /* Index Name NULL */ 2677#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2678#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2679#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2680#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2681#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2682#define SQLITE_COPY 0 /* No longer used */ 2683#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2684 2685/* 2686** CAPI3REF: Tracing And Profiling Functions 2687** METHOD: sqlite3 2688** 2689** These routines register callback functions that can be used for 2690** tracing and profiling the execution of SQL statements. 2691** 2692** ^The callback function registered by sqlite3_trace() is invoked at 2693** various times when an SQL statement is being run by [sqlite3_step()]. 2694** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2695** SQL statement text as the statement first begins executing. 2696** ^(Additional sqlite3_trace() callbacks might occur 2697** as each triggered subprogram is entered. The callbacks for triggers 2698** contain a UTF-8 SQL comment that identifies the trigger.)^ 2699** 2700** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2701** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2702** 2703** ^The callback function registered by sqlite3_profile() is invoked 2704** as each SQL statement finishes. ^The profile callback contains 2705** the original statement text and an estimate of wall-clock time 2706** of how long that statement took to run. ^The profile callback 2707** time is in units of nanoseconds, however the current implementation 2708** is only capable of millisecond resolution so the six least significant 2709** digits in the time are meaningless. Future versions of SQLite 2710** might provide greater resolution on the profiler callback. The 2711** sqlite3_profile() function is considered experimental and is 2712** subject to change in future versions of SQLite. 2713*/ 2714void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2715SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2716 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2717 2718/* 2719** CAPI3REF: Query Progress Callbacks 2720** METHOD: sqlite3 2721** 2722** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2723** function X to be invoked periodically during long running calls to 2724** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2725** database connection D. An example use for this 2726** interface is to keep a GUI updated during a large query. 2727** 2728** ^The parameter P is passed through as the only parameter to the 2729** callback function X. ^The parameter N is the approximate number of 2730** [virtual machine instructions] that are evaluated between successive 2731** invocations of the callback X. ^If N is less than one then the progress 2732** handler is disabled. 2733** 2734** ^Only a single progress handler may be defined at one time per 2735** [database connection]; setting a new progress handler cancels the 2736** old one. ^Setting parameter X to NULL disables the progress handler. 2737** ^The progress handler is also disabled by setting N to a value less 2738** than 1. 2739** 2740** ^If the progress callback returns non-zero, the operation is 2741** interrupted. This feature can be used to implement a 2742** "Cancel" button on a GUI progress dialog box. 2743** 2744** The progress handler callback must not do anything that will modify 2745** the database connection that invoked the progress handler. 2746** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2747** database connections for the meaning of "modify" in this paragraph. 2748** 2749*/ 2750void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2751 2752/* 2753** CAPI3REF: Opening A New Database Connection 2754** CONSTRUCTOR: sqlite3 2755** 2756** ^These routines open an SQLite database file as specified by the 2757** filename argument. ^The filename argument is interpreted as UTF-8 for 2758** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2759** order for sqlite3_open16(). ^(A [database connection] handle is usually 2760** returned in *ppDb, even if an error occurs. The only exception is that 2761** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2762** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2763** object.)^ ^(If the database is opened (and/or created) successfully, then 2764** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2765** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2766** an English language description of the error following a failure of any 2767** of the sqlite3_open() routines. 2768** 2769** ^The default encoding will be UTF-8 for databases created using 2770** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 2771** created using sqlite3_open16() will be UTF-16 in the native byte order. 2772** 2773** Whether or not an error occurs when it is opened, resources 2774** associated with the [database connection] handle should be released by 2775** passing it to [sqlite3_close()] when it is no longer required. 2776** 2777** The sqlite3_open_v2() interface works like sqlite3_open() 2778** except that it accepts two additional parameters for additional control 2779** over the new database connection. ^(The flags parameter to 2780** sqlite3_open_v2() can take one of 2781** the following three values, optionally combined with the 2782** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2783** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2784** 2785** <dl> 2786** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2787** <dd>The database is opened in read-only mode. If the database does not 2788** already exist, an error is returned.</dd>)^ 2789** 2790** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2791** <dd>The database is opened for reading and writing if possible, or reading 2792** only if the file is write protected by the operating system. In either 2793** case the database must already exist, otherwise an error is returned.</dd>)^ 2794** 2795** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2796** <dd>The database is opened for reading and writing, and is created if 2797** it does not already exist. This is the behavior that is always used for 2798** sqlite3_open() and sqlite3_open16().</dd>)^ 2799** </dl> 2800** 2801** If the 3rd parameter to sqlite3_open_v2() is not one of the 2802** combinations shown above optionally combined with other 2803** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2804** then the behavior is undefined. 2805** 2806** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2807** opens in the multi-thread [threading mode] as long as the single-thread 2808** mode has not been set at compile-time or start-time. ^If the 2809** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2810** in the serialized [threading mode] unless single-thread was 2811** previously selected at compile-time or start-time. 2812** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2813** eligible to use [shared cache mode], regardless of whether or not shared 2814** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2815** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2816** participate in [shared cache mode] even if it is enabled. 2817** 2818** ^The fourth parameter to sqlite3_open_v2() is the name of the 2819** [sqlite3_vfs] object that defines the operating system interface that 2820** the new database connection should use. ^If the fourth parameter is 2821** a NULL pointer then the default [sqlite3_vfs] object is used. 2822** 2823** ^If the filename is ":memory:", then a private, temporary in-memory database 2824** is created for the connection. ^This in-memory database will vanish when 2825** the database connection is closed. Future versions of SQLite might 2826** make use of additional special filenames that begin with the ":" character. 2827** It is recommended that when a database filename actually does begin with 2828** a ":" character you should prefix the filename with a pathname such as 2829** "./" to avoid ambiguity. 2830** 2831** ^If the filename is an empty string, then a private, temporary 2832** on-disk database will be created. ^This private database will be 2833** automatically deleted as soon as the database connection is closed. 2834** 2835** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2836** 2837** ^If [URI filename] interpretation is enabled, and the filename argument 2838** begins with "file:", then the filename is interpreted as a URI. ^URI 2839** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2840** set in the fourth argument to sqlite3_open_v2(), or if it has 2841** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2842** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2843** As of SQLite version 3.7.7, URI filename interpretation is turned off 2844** by default, but future releases of SQLite might enable URI filename 2845** interpretation by default. See "[URI filenames]" for additional 2846** information. 2847** 2848** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2849** authority, then it must be either an empty string or the string 2850** "localhost". ^If the authority is not an empty string or "localhost", an 2851** error is returned to the caller. ^The fragment component of a URI, if 2852** present, is ignored. 2853** 2854** ^SQLite uses the path component of the URI as the name of the disk file 2855** which contains the database. ^If the path begins with a '/' character, 2856** then it is interpreted as an absolute path. ^If the path does not begin 2857** with a '/' (meaning that the authority section is omitted from the URI) 2858** then the path is interpreted as a relative path. 2859** ^(On windows, the first component of an absolute path 2860** is a drive specification (e.g. "C:").)^ 2861** 2862** [[core URI query parameters]] 2863** The query component of a URI may contain parameters that are interpreted 2864** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2865** SQLite and its built-in [VFSes] interpret the 2866** following query parameters: 2867** 2868** <ul> 2869** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2870** a VFS object that provides the operating system interface that should 2871** be used to access the database file on disk. ^If this option is set to 2872** an empty string the default VFS object is used. ^Specifying an unknown 2873** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2874** present, then the VFS specified by the option takes precedence over 2875** the value passed as the fourth parameter to sqlite3_open_v2(). 2876** 2877** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2878** "rwc", or "memory". Attempting to set it to any other value is 2879** an error)^. 2880** ^If "ro" is specified, then the database is opened for read-only 2881** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2882** third argument to sqlite3_open_v2(). ^If the mode option is set to 2883** "rw", then the database is opened for read-write (but not create) 2884** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2885** been set. ^Value "rwc" is equivalent to setting both 2886** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2887** set to "memory" then a pure [in-memory database] that never reads 2888** or writes from disk is used. ^It is an error to specify a value for 2889** the mode parameter that is less restrictive than that specified by 2890** the flags passed in the third parameter to sqlite3_open_v2(). 2891** 2892** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2893** "private". ^Setting it to "shared" is equivalent to setting the 2894** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2895** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2896** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2897** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2898** a URI filename, its value overrides any behavior requested by setting 2899** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2900** 2901** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 2902** [powersafe overwrite] property does or does not apply to the 2903** storage media on which the database file resides. 2904** 2905** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 2906** which if set disables file locking in rollback journal modes. This 2907** is useful for accessing a database on a filesystem that does not 2908** support locking. Caution: Database corruption might result if two 2909** or more processes write to the same database and any one of those 2910** processes uses nolock=1. 2911** 2912** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 2913** parameter that indicates that the database file is stored on 2914** read-only media. ^When immutable is set, SQLite assumes that the 2915** database file cannot be changed, even by a process with higher 2916** privilege, and so the database is opened read-only and all locking 2917** and change detection is disabled. Caution: Setting the immutable 2918** property on a database file that does in fact change can result 2919** in incorrect query results and/or [SQLITE_CORRUPT] errors. 2920** See also: [SQLITE_IOCAP_IMMUTABLE]. 2921** 2922** </ul> 2923** 2924** ^Specifying an unknown parameter in the query component of a URI is not an 2925** error. Future versions of SQLite might understand additional query 2926** parameters. See "[query parameters with special meaning to SQLite]" for 2927** additional information. 2928** 2929** [[URI filename examples]] <h3>URI filename examples</h3> 2930** 2931** <table border="1" align=center cellpadding=5> 2932** <tr><th> URI filenames <th> Results 2933** <tr><td> file:data.db <td> 2934** Open the file "data.db" in the current directory. 2935** <tr><td> file:/home/fred/data.db<br> 2936** file:///home/fred/data.db <br> 2937** file://localhost/home/fred/data.db <br> <td> 2938** Open the database file "/home/fred/data.db". 2939** <tr><td> file://darkstar/home/fred/data.db <td> 2940** An error. "darkstar" is not a recognized authority. 2941** <tr><td style="white-space:nowrap"> 2942** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2943** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2944** C:. Note that the %20 escaping in this example is not strictly 2945** necessary - space characters can be used literally 2946** in URI filenames. 2947** <tr><td> file:data.db?mode=ro&cache=private <td> 2948** Open file "data.db" in the current directory for read-only access. 2949** Regardless of whether or not shared-cache mode is enabled by 2950** default, use a private cache. 2951** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 2952** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 2953** that uses dot-files in place of posix advisory locking. 2954** <tr><td> file:data.db?mode=readonly <td> 2955** An error. "readonly" is not a valid option for the "mode" parameter. 2956** </table> 2957** 2958** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2959** query components of a URI. A hexadecimal escape sequence consists of a 2960** percent sign - "%" - followed by exactly two hexadecimal digits 2961** specifying an octet value. ^Before the path or query components of a 2962** URI filename are interpreted, they are encoded using UTF-8 and all 2963** hexadecimal escape sequences replaced by a single byte containing the 2964** corresponding octet. If this process generates an invalid UTF-8 encoding, 2965** the results are undefined. 2966** 2967** <b>Note to Windows users:</b> The encoding used for the filename argument 2968** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2969** codepage is currently defined. Filenames containing international 2970** characters must be converted to UTF-8 prior to passing them into 2971** sqlite3_open() or sqlite3_open_v2(). 2972** 2973** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2974** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2975** features that require the use of temporary files may fail. 2976** 2977** See also: [sqlite3_temp_directory] 2978*/ 2979int sqlite3_open( 2980 const char *filename, /* Database filename (UTF-8) */ 2981 sqlite3 **ppDb /* OUT: SQLite db handle */ 2982); 2983int sqlite3_open16( 2984 const void *filename, /* Database filename (UTF-16) */ 2985 sqlite3 **ppDb /* OUT: SQLite db handle */ 2986); 2987int sqlite3_open_v2( 2988 const char *filename, /* Database filename (UTF-8) */ 2989 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2990 int flags, /* Flags */ 2991 const char *zVfs /* Name of VFS module to use */ 2992); 2993 2994/* 2995** CAPI3REF: Obtain Values For URI Parameters 2996** 2997** These are utility routines, useful to VFS implementations, that check 2998** to see if a database file was a URI that contained a specific query 2999** parameter, and if so obtains the value of that query parameter. 3000** 3001** If F is the database filename pointer passed into the xOpen() method of 3002** a VFS implementation when the flags parameter to xOpen() has one or 3003** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3004** P is the name of the query parameter, then 3005** sqlite3_uri_parameter(F,P) returns the value of the P 3006** parameter if it exists or a NULL pointer if P does not appear as a 3007** query parameter on F. If P is a query parameter of F 3008** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3009** a pointer to an empty string. 3010** 3011** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3012** parameter and returns true (1) or false (0) according to the value 3013** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3014** value of query parameter P is one of "yes", "true", or "on" in any 3015** case or if the value begins with a non-zero number. The 3016** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3017** query parameter P is one of "no", "false", or "off" in any case or 3018** if the value begins with a numeric zero. If P is not a query 3019** parameter on F or if the value of P is does not match any of the 3020** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3021** 3022** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3023** 64-bit signed integer and returns that integer, or D if P does not 3024** exist. If the value of P is something other than an integer, then 3025** zero is returned. 3026** 3027** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3028** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3029** is not a database file pathname pointer that SQLite passed into the xOpen 3030** VFS method, then the behavior of this routine is undefined and probably 3031** undesirable. 3032*/ 3033const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3034int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3035sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3036 3037 3038/* 3039** CAPI3REF: Error Codes And Messages 3040** METHOD: sqlite3 3041** 3042** ^If the most recent sqlite3_* API call associated with 3043** [database connection] D failed, then the sqlite3_errcode(D) interface 3044** returns the numeric [result code] or [extended result code] for that 3045** API call. 3046** If the most recent API call was successful, 3047** then the return value from sqlite3_errcode() is undefined. 3048** ^The sqlite3_extended_errcode() 3049** interface is the same except that it always returns the 3050** [extended result code] even when extended result codes are 3051** disabled. 3052** 3053** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3054** text that describes the error, as either UTF-8 or UTF-16 respectively. 3055** ^(Memory to hold the error message string is managed internally. 3056** The application does not need to worry about freeing the result. 3057** However, the error string might be overwritten or deallocated by 3058** subsequent calls to other SQLite interface functions.)^ 3059** 3060** ^The sqlite3_errstr() interface returns the English-language text 3061** that describes the [result code], as UTF-8. 3062** ^(Memory to hold the error message string is managed internally 3063** and must not be freed by the application)^. 3064** 3065** When the serialized [threading mode] is in use, it might be the 3066** case that a second error occurs on a separate thread in between 3067** the time of the first error and the call to these interfaces. 3068** When that happens, the second error will be reported since these 3069** interfaces always report the most recent result. To avoid 3070** this, each thread can obtain exclusive use of the [database connection] D 3071** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3072** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3073** all calls to the interfaces listed here are completed. 3074** 3075** If an interface fails with SQLITE_MISUSE, that means the interface 3076** was invoked incorrectly by the application. In that case, the 3077** error code and message may or may not be set. 3078*/ 3079int sqlite3_errcode(sqlite3 *db); 3080int sqlite3_extended_errcode(sqlite3 *db); 3081const char *sqlite3_errmsg(sqlite3*); 3082const void *sqlite3_errmsg16(sqlite3*); 3083const char *sqlite3_errstr(int); 3084 3085/* 3086** CAPI3REF: Prepared Statement Object 3087** KEYWORDS: {prepared statement} {prepared statements} 3088** 3089** An instance of this object represents a single SQL statement that 3090** has been compiled into binary form and is ready to be evaluated. 3091** 3092** Think of each SQL statement as a separate computer program. The 3093** original SQL text is source code. A prepared statement object 3094** is the compiled object code. All SQL must be converted into a 3095** prepared statement before it can be run. 3096** 3097** The life-cycle of a prepared statement object usually goes like this: 3098** 3099** <ol> 3100** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3101** <li> Bind values to [parameters] using the sqlite3_bind_*() 3102** interfaces. 3103** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3104** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3105** to step 2. Do this zero or more times. 3106** <li> Destroy the object using [sqlite3_finalize()]. 3107** </ol> 3108*/ 3109typedef struct sqlite3_stmt sqlite3_stmt; 3110 3111/* 3112** CAPI3REF: Run-time Limits 3113** METHOD: sqlite3 3114** 3115** ^(This interface allows the size of various constructs to be limited 3116** on a connection by connection basis. The first parameter is the 3117** [database connection] whose limit is to be set or queried. The 3118** second parameter is one of the [limit categories] that define a 3119** class of constructs to be size limited. The third parameter is the 3120** new limit for that construct.)^ 3121** 3122** ^If the new limit is a negative number, the limit is unchanged. 3123** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3124** [limits | hard upper bound] 3125** set at compile-time by a C preprocessor macro called 3126** [limits | SQLITE_MAX_<i>NAME</i>]. 3127** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3128** ^Attempts to increase a limit above its hard upper bound are 3129** silently truncated to the hard upper bound. 3130** 3131** ^Regardless of whether or not the limit was changed, the 3132** [sqlite3_limit()] interface returns the prior value of the limit. 3133** ^Hence, to find the current value of a limit without changing it, 3134** simply invoke this interface with the third parameter set to -1. 3135** 3136** Run-time limits are intended for use in applications that manage 3137** both their own internal database and also databases that are controlled 3138** by untrusted external sources. An example application might be a 3139** web browser that has its own databases for storing history and 3140** separate databases controlled by JavaScript applications downloaded 3141** off the Internet. The internal databases can be given the 3142** large, default limits. Databases managed by external sources can 3143** be given much smaller limits designed to prevent a denial of service 3144** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3145** interface to further control untrusted SQL. The size of the database 3146** created by an untrusted script can be contained using the 3147** [max_page_count] [PRAGMA]. 3148** 3149** New run-time limit categories may be added in future releases. 3150*/ 3151int sqlite3_limit(sqlite3*, int id, int newVal); 3152 3153/* 3154** CAPI3REF: Run-Time Limit Categories 3155** KEYWORDS: {limit category} {*limit categories} 3156** 3157** These constants define various performance limits 3158** that can be lowered at run-time using [sqlite3_limit()]. 3159** The synopsis of the meanings of the various limits is shown below. 3160** Additional information is available at [limits | Limits in SQLite]. 3161** 3162** <dl> 3163** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3164** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3165** 3166** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3167** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3168** 3169** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3170** <dd>The maximum number of columns in a table definition or in the 3171** result set of a [SELECT] or the maximum number of columns in an index 3172** or in an ORDER BY or GROUP BY clause.</dd>)^ 3173** 3174** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3175** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3176** 3177** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3178** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3179** 3180** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3181** <dd>The maximum number of instructions in a virtual machine program 3182** used to implement an SQL statement. This limit is not currently 3183** enforced, though that might be added in some future release of 3184** SQLite.</dd>)^ 3185** 3186** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3187** <dd>The maximum number of arguments on a function.</dd>)^ 3188** 3189** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3190** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3191** 3192** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3193** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3194** <dd>The maximum length of the pattern argument to the [LIKE] or 3195** [GLOB] operators.</dd>)^ 3196** 3197** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3198** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3199** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3200** 3201** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3202** <dd>The maximum depth of recursion for triggers.</dd>)^ 3203** 3204** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3205** <dd>The maximum number of auxiliary worker threads that a single 3206** [prepared statement] may start.</dd>)^ 3207** </dl> 3208*/ 3209#define SQLITE_LIMIT_LENGTH 0 3210#define SQLITE_LIMIT_SQL_LENGTH 1 3211#define SQLITE_LIMIT_COLUMN 2 3212#define SQLITE_LIMIT_EXPR_DEPTH 3 3213#define SQLITE_LIMIT_COMPOUND_SELECT 4 3214#define SQLITE_LIMIT_VDBE_OP 5 3215#define SQLITE_LIMIT_FUNCTION_ARG 6 3216#define SQLITE_LIMIT_ATTACHED 7 3217#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3218#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3219#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3220#define SQLITE_LIMIT_WORKER_THREADS 11 3221 3222/* 3223** CAPI3REF: Compiling An SQL Statement 3224** KEYWORDS: {SQL statement compiler} 3225** METHOD: sqlite3 3226** CONSTRUCTOR: sqlite3_stmt 3227** 3228** To execute an SQL query, it must first be compiled into a byte-code 3229** program using one of these routines. 3230** 3231** The first argument, "db", is a [database connection] obtained from a 3232** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3233** [sqlite3_open16()]. The database connection must not have been closed. 3234** 3235** The second argument, "zSql", is the statement to be compiled, encoded 3236** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3237** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3238** use UTF-16. 3239** 3240** ^If the nByte argument is negative, then zSql is read up to the 3241** first zero terminator. ^If nByte is positive, then it is the 3242** number of bytes read from zSql. ^If nByte is zero, then no prepared 3243** statement is generated. 3244** If the caller knows that the supplied string is nul-terminated, then 3245** there is a small performance advantage to passing an nByte parameter that 3246** is the number of bytes in the input string <i>including</i> 3247** the nul-terminator. 3248** 3249** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3250** past the end of the first SQL statement in zSql. These routines only 3251** compile the first statement in zSql, so *pzTail is left pointing to 3252** what remains uncompiled. 3253** 3254** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3255** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3256** to NULL. ^If the input text contains no SQL (if the input is an empty 3257** string or a comment) then *ppStmt is set to NULL. 3258** The calling procedure is responsible for deleting the compiled 3259** SQL statement using [sqlite3_finalize()] after it has finished with it. 3260** ppStmt may not be NULL. 3261** 3262** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3263** otherwise an [error code] is returned. 3264** 3265** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3266** recommended for all new programs. The two older interfaces are retained 3267** for backwards compatibility, but their use is discouraged. 3268** ^In the "v2" interfaces, the prepared statement 3269** that is returned (the [sqlite3_stmt] object) contains a copy of the 3270** original SQL text. This causes the [sqlite3_step()] interface to 3271** behave differently in three ways: 3272** 3273** <ol> 3274** <li> 3275** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3276** always used to do, [sqlite3_step()] will automatically recompile the SQL 3277** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3278** retries will occur before sqlite3_step() gives up and returns an error. 3279** </li> 3280** 3281** <li> 3282** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3283** [error codes] or [extended error codes]. ^The legacy behavior was that 3284** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3285** and the application would have to make a second call to [sqlite3_reset()] 3286** in order to find the underlying cause of the problem. With the "v2" prepare 3287** interfaces, the underlying reason for the error is returned immediately. 3288** </li> 3289** 3290** <li> 3291** ^If the specific value bound to [parameter | host parameter] in the 3292** WHERE clause might influence the choice of query plan for a statement, 3293** then the statement will be automatically recompiled, as if there had been 3294** a schema change, on the first [sqlite3_step()] call following any change 3295** to the [sqlite3_bind_text | bindings] of that [parameter]. 3296** ^The specific value of WHERE-clause [parameter] might influence the 3297** choice of query plan if the parameter is the left-hand side of a [LIKE] 3298** or [GLOB] operator or if the parameter is compared to an indexed column 3299** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3300** </li> 3301** </ol> 3302*/ 3303int sqlite3_prepare( 3304 sqlite3 *db, /* Database handle */ 3305 const char *zSql, /* SQL statement, UTF-8 encoded */ 3306 int nByte, /* Maximum length of zSql in bytes. */ 3307 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3308 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3309); 3310int sqlite3_prepare_v2( 3311 sqlite3 *db, /* Database handle */ 3312 const char *zSql, /* SQL statement, UTF-8 encoded */ 3313 int nByte, /* Maximum length of zSql in bytes. */ 3314 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3315 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3316); 3317int sqlite3_prepare16( 3318 sqlite3 *db, /* Database handle */ 3319 const void *zSql, /* SQL statement, UTF-16 encoded */ 3320 int nByte, /* Maximum length of zSql in bytes. */ 3321 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3322 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3323); 3324int sqlite3_prepare16_v2( 3325 sqlite3 *db, /* Database handle */ 3326 const void *zSql, /* SQL statement, UTF-16 encoded */ 3327 int nByte, /* Maximum length of zSql in bytes. */ 3328 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3329 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3330); 3331 3332/* 3333** CAPI3REF: Retrieving Statement SQL 3334** METHOD: sqlite3_stmt 3335** 3336** ^This interface can be used to retrieve a saved copy of the original 3337** SQL text used to create a [prepared statement] if that statement was 3338** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3339*/ 3340const char *sqlite3_sql(sqlite3_stmt *pStmt); 3341 3342/* 3343** CAPI3REF: Determine If An SQL Statement Writes The Database 3344** METHOD: sqlite3_stmt 3345** 3346** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3347** and only if the [prepared statement] X makes no direct changes to 3348** the content of the database file. 3349** 3350** Note that [application-defined SQL functions] or 3351** [virtual tables] might change the database indirectly as a side effect. 3352** ^(For example, if an application defines a function "eval()" that 3353** calls [sqlite3_exec()], then the following SQL statement would 3354** change the database file through side-effects: 3355** 3356** <blockquote><pre> 3357** SELECT eval('DELETE FROM t1') FROM t2; 3358** </pre></blockquote> 3359** 3360** But because the [SELECT] statement does not change the database file 3361** directly, sqlite3_stmt_readonly() would still return true.)^ 3362** 3363** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3364** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3365** since the statements themselves do not actually modify the database but 3366** rather they control the timing of when other statements modify the 3367** database. ^The [ATTACH] and [DETACH] statements also cause 3368** sqlite3_stmt_readonly() to return true since, while those statements 3369** change the configuration of a database connection, they do not make 3370** changes to the content of the database files on disk. 3371*/ 3372int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3373 3374/* 3375** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3376** METHOD: sqlite3_stmt 3377** 3378** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3379** [prepared statement] S has been stepped at least once using 3380** [sqlite3_step(S)] but has neither run to completion (returned 3381** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3382** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3383** interface returns false if S is a NULL pointer. If S is not a 3384** NULL pointer and is not a pointer to a valid [prepared statement] 3385** object, then the behavior is undefined and probably undesirable. 3386** 3387** This interface can be used in combination [sqlite3_next_stmt()] 3388** to locate all prepared statements associated with a database 3389** connection that are in need of being reset. This can be used, 3390** for example, in diagnostic routines to search for prepared 3391** statements that are holding a transaction open. 3392*/ 3393int sqlite3_stmt_busy(sqlite3_stmt*); 3394 3395/* 3396** CAPI3REF: Dynamically Typed Value Object 3397** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3398** 3399** SQLite uses the sqlite3_value object to represent all values 3400** that can be stored in a database table. SQLite uses dynamic typing 3401** for the values it stores. ^Values stored in sqlite3_value objects 3402** can be integers, floating point values, strings, BLOBs, or NULL. 3403** 3404** An sqlite3_value object may be either "protected" or "unprotected". 3405** Some interfaces require a protected sqlite3_value. Other interfaces 3406** will accept either a protected or an unprotected sqlite3_value. 3407** Every interface that accepts sqlite3_value arguments specifies 3408** whether or not it requires a protected sqlite3_value. The 3409** [sqlite3_value_dup()] interface can be used to construct a new 3410** protected sqlite3_value from an unprotected sqlite3_value. 3411** 3412** The terms "protected" and "unprotected" refer to whether or not 3413** a mutex is held. An internal mutex is held for a protected 3414** sqlite3_value object but no mutex is held for an unprotected 3415** sqlite3_value object. If SQLite is compiled to be single-threaded 3416** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3417** or if SQLite is run in one of reduced mutex modes 3418** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3419** then there is no distinction between protected and unprotected 3420** sqlite3_value objects and they can be used interchangeably. However, 3421** for maximum code portability it is recommended that applications 3422** still make the distinction between protected and unprotected 3423** sqlite3_value objects even when not strictly required. 3424** 3425** ^The sqlite3_value objects that are passed as parameters into the 3426** implementation of [application-defined SQL functions] are protected. 3427** ^The sqlite3_value object returned by 3428** [sqlite3_column_value()] is unprotected. 3429** Unprotected sqlite3_value objects may only be used with 3430** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3431** The [sqlite3_value_blob | sqlite3_value_type()] family of 3432** interfaces require protected sqlite3_value objects. 3433*/ 3434typedef struct Mem sqlite3_value; 3435 3436/* 3437** CAPI3REF: SQL Function Context Object 3438** 3439** The context in which an SQL function executes is stored in an 3440** sqlite3_context object. ^A pointer to an sqlite3_context object 3441** is always first parameter to [application-defined SQL functions]. 3442** The application-defined SQL function implementation will pass this 3443** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3444** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3445** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3446** and/or [sqlite3_set_auxdata()]. 3447*/ 3448typedef struct sqlite3_context sqlite3_context; 3449 3450/* 3451** CAPI3REF: Binding Values To Prepared Statements 3452** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3453** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3454** METHOD: sqlite3_stmt 3455** 3456** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3457** literals may be replaced by a [parameter] that matches one of following 3458** templates: 3459** 3460** <ul> 3461** <li> ? 3462** <li> ?NNN 3463** <li> :VVV 3464** <li> @VVV 3465** <li> $VVV 3466** </ul> 3467** 3468** In the templates above, NNN represents an integer literal, 3469** and VVV represents an alphanumeric identifier.)^ ^The values of these 3470** parameters (also called "host parameter names" or "SQL parameters") 3471** can be set using the sqlite3_bind_*() routines defined here. 3472** 3473** ^The first argument to the sqlite3_bind_*() routines is always 3474** a pointer to the [sqlite3_stmt] object returned from 3475** [sqlite3_prepare_v2()] or its variants. 3476** 3477** ^The second argument is the index of the SQL parameter to be set. 3478** ^The leftmost SQL parameter has an index of 1. ^When the same named 3479** SQL parameter is used more than once, second and subsequent 3480** occurrences have the same index as the first occurrence. 3481** ^The index for named parameters can be looked up using the 3482** [sqlite3_bind_parameter_index()] API if desired. ^The index 3483** for "?NNN" parameters is the value of NNN. 3484** ^The NNN value must be between 1 and the [sqlite3_limit()] 3485** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3486** 3487** ^The third argument is the value to bind to the parameter. 3488** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3489** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3490** is ignored and the end result is the same as sqlite3_bind_null(). 3491** 3492** ^(In those routines that have a fourth argument, its value is the 3493** number of bytes in the parameter. To be clear: the value is the 3494** number of <u>bytes</u> in the value, not the number of characters.)^ 3495** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3496** is negative, then the length of the string is 3497** the number of bytes up to the first zero terminator. 3498** If the fourth parameter to sqlite3_bind_blob() is negative, then 3499** the behavior is undefined. 3500** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3501** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3502** that parameter must be the byte offset 3503** where the NUL terminator would occur assuming the string were NUL 3504** terminated. If any NUL characters occur at byte offsets less than 3505** the value of the fourth parameter then the resulting string value will 3506** contain embedded NULs. The result of expressions involving strings 3507** with embedded NULs is undefined. 3508** 3509** ^The fifth argument to the BLOB and string binding interfaces 3510** is a destructor used to dispose of the BLOB or 3511** string after SQLite has finished with it. ^The destructor is called 3512** to dispose of the BLOB or string even if the call to bind API fails. 3513** ^If the fifth argument is 3514** the special value [SQLITE_STATIC], then SQLite assumes that the 3515** information is in static, unmanaged space and does not need to be freed. 3516** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3517** SQLite makes its own private copy of the data immediately, before 3518** the sqlite3_bind_*() routine returns. 3519** 3520** ^The sixth argument to sqlite3_bind_text64() must be one of 3521** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3522** to specify the encoding of the text in the third parameter. If 3523** the sixth argument to sqlite3_bind_text64() is not one of the 3524** allowed values shown above, or if the text encoding is different 3525** from the encoding specified by the sixth parameter, then the behavior 3526** is undefined. 3527** 3528** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3529** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3530** (just an integer to hold its size) while it is being processed. 3531** Zeroblobs are intended to serve as placeholders for BLOBs whose 3532** content is later written using 3533** [sqlite3_blob_open | incremental BLOB I/O] routines. 3534** ^A negative value for the zeroblob results in a zero-length BLOB. 3535** 3536** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3537** for the [prepared statement] or with a prepared statement for which 3538** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3539** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3540** routine is passed a [prepared statement] that has been finalized, the 3541** result is undefined and probably harmful. 3542** 3543** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3544** ^Unbound parameters are interpreted as NULL. 3545** 3546** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3547** [error code] if anything goes wrong. 3548** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3549** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3550** [SQLITE_MAX_LENGTH]. 3551** ^[SQLITE_RANGE] is returned if the parameter 3552** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3553** 3554** See also: [sqlite3_bind_parameter_count()], 3555** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3556*/ 3557int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3558int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3559 void(*)(void*)); 3560int sqlite3_bind_double(sqlite3_stmt*, int, double); 3561int sqlite3_bind_int(sqlite3_stmt*, int, int); 3562int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3563int sqlite3_bind_null(sqlite3_stmt*, int); 3564int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3565int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3566int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3567 void(*)(void*), unsigned char encoding); 3568int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3569int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3570int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3571 3572/* 3573** CAPI3REF: Number Of SQL Parameters 3574** METHOD: sqlite3_stmt 3575** 3576** ^This routine can be used to find the number of [SQL parameters] 3577** in a [prepared statement]. SQL parameters are tokens of the 3578** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3579** placeholders for values that are [sqlite3_bind_blob | bound] 3580** to the parameters at a later time. 3581** 3582** ^(This routine actually returns the index of the largest (rightmost) 3583** parameter. For all forms except ?NNN, this will correspond to the 3584** number of unique parameters. If parameters of the ?NNN form are used, 3585** there may be gaps in the list.)^ 3586** 3587** See also: [sqlite3_bind_blob|sqlite3_bind()], 3588** [sqlite3_bind_parameter_name()], and 3589** [sqlite3_bind_parameter_index()]. 3590*/ 3591int sqlite3_bind_parameter_count(sqlite3_stmt*); 3592 3593/* 3594** CAPI3REF: Name Of A Host Parameter 3595** METHOD: sqlite3_stmt 3596** 3597** ^The sqlite3_bind_parameter_name(P,N) interface returns 3598** the name of the N-th [SQL parameter] in the [prepared statement] P. 3599** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3600** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3601** respectively. 3602** In other words, the initial ":" or "$" or "@" or "?" 3603** is included as part of the name.)^ 3604** ^Parameters of the form "?" without a following integer have no name 3605** and are referred to as "nameless" or "anonymous parameters". 3606** 3607** ^The first host parameter has an index of 1, not 0. 3608** 3609** ^If the value N is out of range or if the N-th parameter is 3610** nameless, then NULL is returned. ^The returned string is 3611** always in UTF-8 encoding even if the named parameter was 3612** originally specified as UTF-16 in [sqlite3_prepare16()] or 3613** [sqlite3_prepare16_v2()]. 3614** 3615** See also: [sqlite3_bind_blob|sqlite3_bind()], 3616** [sqlite3_bind_parameter_count()], and 3617** [sqlite3_bind_parameter_index()]. 3618*/ 3619const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3620 3621/* 3622** CAPI3REF: Index Of A Parameter With A Given Name 3623** METHOD: sqlite3_stmt 3624** 3625** ^Return the index of an SQL parameter given its name. ^The 3626** index value returned is suitable for use as the second 3627** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3628** is returned if no matching parameter is found. ^The parameter 3629** name must be given in UTF-8 even if the original statement 3630** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3631** 3632** See also: [sqlite3_bind_blob|sqlite3_bind()], 3633** [sqlite3_bind_parameter_count()], and 3634** [sqlite3_bind_parameter_name()]. 3635*/ 3636int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3637 3638/* 3639** CAPI3REF: Reset All Bindings On A Prepared Statement 3640** METHOD: sqlite3_stmt 3641** 3642** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3643** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3644** ^Use this routine to reset all host parameters to NULL. 3645*/ 3646int sqlite3_clear_bindings(sqlite3_stmt*); 3647 3648/* 3649** CAPI3REF: Number Of Columns In A Result Set 3650** METHOD: sqlite3_stmt 3651** 3652** ^Return the number of columns in the result set returned by the 3653** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3654** statement that does not return data (for example an [UPDATE]). 3655** 3656** See also: [sqlite3_data_count()] 3657*/ 3658int sqlite3_column_count(sqlite3_stmt *pStmt); 3659 3660/* 3661** CAPI3REF: Column Names In A Result Set 3662** METHOD: sqlite3_stmt 3663** 3664** ^These routines return the name assigned to a particular column 3665** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3666** interface returns a pointer to a zero-terminated UTF-8 string 3667** and sqlite3_column_name16() returns a pointer to a zero-terminated 3668** UTF-16 string. ^The first parameter is the [prepared statement] 3669** that implements the [SELECT] statement. ^The second parameter is the 3670** column number. ^The leftmost column is number 0. 3671** 3672** ^The returned string pointer is valid until either the [prepared statement] 3673** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3674** reprepared by the first call to [sqlite3_step()] for a particular run 3675** or until the next call to 3676** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3677** 3678** ^If sqlite3_malloc() fails during the processing of either routine 3679** (for example during a conversion from UTF-8 to UTF-16) then a 3680** NULL pointer is returned. 3681** 3682** ^The name of a result column is the value of the "AS" clause for 3683** that column, if there is an AS clause. If there is no AS clause 3684** then the name of the column is unspecified and may change from 3685** one release of SQLite to the next. 3686*/ 3687const char *sqlite3_column_name(sqlite3_stmt*, int N); 3688const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3689 3690/* 3691** CAPI3REF: Source Of Data In A Query Result 3692** METHOD: sqlite3_stmt 3693** 3694** ^These routines provide a means to determine the database, table, and 3695** table column that is the origin of a particular result column in 3696** [SELECT] statement. 3697** ^The name of the database or table or column can be returned as 3698** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3699** the database name, the _table_ routines return the table name, and 3700** the origin_ routines return the column name. 3701** ^The returned string is valid until the [prepared statement] is destroyed 3702** using [sqlite3_finalize()] or until the statement is automatically 3703** reprepared by the first call to [sqlite3_step()] for a particular run 3704** or until the same information is requested 3705** again in a different encoding. 3706** 3707** ^The names returned are the original un-aliased names of the 3708** database, table, and column. 3709** 3710** ^The first argument to these interfaces is a [prepared statement]. 3711** ^These functions return information about the Nth result column returned by 3712** the statement, where N is the second function argument. 3713** ^The left-most column is column 0 for these routines. 3714** 3715** ^If the Nth column returned by the statement is an expression or 3716** subquery and is not a column value, then all of these functions return 3717** NULL. ^These routine might also return NULL if a memory allocation error 3718** occurs. ^Otherwise, they return the name of the attached database, table, 3719** or column that query result column was extracted from. 3720** 3721** ^As with all other SQLite APIs, those whose names end with "16" return 3722** UTF-16 encoded strings and the other functions return UTF-8. 3723** 3724** ^These APIs are only available if the library was compiled with the 3725** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3726** 3727** If two or more threads call one or more of these routines against the same 3728** prepared statement and column at the same time then the results are 3729** undefined. 3730** 3731** If two or more threads call one or more 3732** [sqlite3_column_database_name | column metadata interfaces] 3733** for the same [prepared statement] and result column 3734** at the same time then the results are undefined. 3735*/ 3736const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3737const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3738const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3739const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3740const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3741const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3742 3743/* 3744** CAPI3REF: Declared Datatype Of A Query Result 3745** METHOD: sqlite3_stmt 3746** 3747** ^(The first parameter is a [prepared statement]. 3748** If this statement is a [SELECT] statement and the Nth column of the 3749** returned result set of that [SELECT] is a table column (not an 3750** expression or subquery) then the declared type of the table 3751** column is returned.)^ ^If the Nth column of the result set is an 3752** expression or subquery, then a NULL pointer is returned. 3753** ^The returned string is always UTF-8 encoded. 3754** 3755** ^(For example, given the database schema: 3756** 3757** CREATE TABLE t1(c1 VARIANT); 3758** 3759** and the following statement to be compiled: 3760** 3761** SELECT c1 + 1, c1 FROM t1; 3762** 3763** this routine would return the string "VARIANT" for the second result 3764** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3765** 3766** ^SQLite uses dynamic run-time typing. ^So just because a column 3767** is declared to contain a particular type does not mean that the 3768** data stored in that column is of the declared type. SQLite is 3769** strongly typed, but the typing is dynamic not static. ^Type 3770** is associated with individual values, not with the containers 3771** used to hold those values. 3772*/ 3773const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3774const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3775 3776/* 3777** CAPI3REF: Evaluate An SQL Statement 3778** METHOD: sqlite3_stmt 3779** 3780** After a [prepared statement] has been prepared using either 3781** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3782** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3783** must be called one or more times to evaluate the statement. 3784** 3785** The details of the behavior of the sqlite3_step() interface depend 3786** on whether the statement was prepared using the newer "v2" interface 3787** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3788** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3789** new "v2" interface is recommended for new applications but the legacy 3790** interface will continue to be supported. 3791** 3792** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3793** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3794** ^With the "v2" interface, any of the other [result codes] or 3795** [extended result codes] might be returned as well. 3796** 3797** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3798** database locks it needs to do its job. ^If the statement is a [COMMIT] 3799** or occurs outside of an explicit transaction, then you can retry the 3800** statement. If the statement is not a [COMMIT] and occurs within an 3801** explicit transaction then you should rollback the transaction before 3802** continuing. 3803** 3804** ^[SQLITE_DONE] means that the statement has finished executing 3805** successfully. sqlite3_step() should not be called again on this virtual 3806** machine without first calling [sqlite3_reset()] to reset the virtual 3807** machine back to its initial state. 3808** 3809** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3810** is returned each time a new row of data is ready for processing by the 3811** caller. The values may be accessed using the [column access functions]. 3812** sqlite3_step() is called again to retrieve the next row of data. 3813** 3814** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3815** violation) has occurred. sqlite3_step() should not be called again on 3816** the VM. More information may be found by calling [sqlite3_errmsg()]. 3817** ^With the legacy interface, a more specific error code (for example, 3818** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3819** can be obtained by calling [sqlite3_reset()] on the 3820** [prepared statement]. ^In the "v2" interface, 3821** the more specific error code is returned directly by sqlite3_step(). 3822** 3823** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3824** Perhaps it was called on a [prepared statement] that has 3825** already been [sqlite3_finalize | finalized] or on one that had 3826** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3827** be the case that the same database connection is being used by two or 3828** more threads at the same moment in time. 3829** 3830** For all versions of SQLite up to and including 3.6.23.1, a call to 3831** [sqlite3_reset()] was required after sqlite3_step() returned anything 3832** other than [SQLITE_ROW] before any subsequent invocation of 3833** sqlite3_step(). Failure to reset the prepared statement using 3834** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3835** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3836** calling [sqlite3_reset()] automatically in this circumstance rather 3837** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3838** break because any application that ever receives an SQLITE_MISUSE error 3839** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3840** can be used to restore the legacy behavior. 3841** 3842** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3843** API always returns a generic error code, [SQLITE_ERROR], following any 3844** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3845** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3846** specific [error codes] that better describes the error. 3847** We admit that this is a goofy design. The problem has been fixed 3848** with the "v2" interface. If you prepare all of your SQL statements 3849** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3850** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3851** then the more specific [error codes] are returned directly 3852** by sqlite3_step(). The use of the "v2" interface is recommended. 3853*/ 3854int sqlite3_step(sqlite3_stmt*); 3855 3856/* 3857** CAPI3REF: Number of columns in a result set 3858** METHOD: sqlite3_stmt 3859** 3860** ^The sqlite3_data_count(P) interface returns the number of columns in the 3861** current row of the result set of [prepared statement] P. 3862** ^If prepared statement P does not have results ready to return 3863** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3864** interfaces) then sqlite3_data_count(P) returns 0. 3865** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3866** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3867** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3868** will return non-zero if previous call to [sqlite3_step](P) returned 3869** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3870** where it always returns zero since each step of that multi-step 3871** pragma returns 0 columns of data. 3872** 3873** See also: [sqlite3_column_count()] 3874*/ 3875int sqlite3_data_count(sqlite3_stmt *pStmt); 3876 3877/* 3878** CAPI3REF: Fundamental Datatypes 3879** KEYWORDS: SQLITE_TEXT 3880** 3881** ^(Every value in SQLite has one of five fundamental datatypes: 3882** 3883** <ul> 3884** <li> 64-bit signed integer 3885** <li> 64-bit IEEE floating point number 3886** <li> string 3887** <li> BLOB 3888** <li> NULL 3889** </ul>)^ 3890** 3891** These constants are codes for each of those types. 3892** 3893** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3894** for a completely different meaning. Software that links against both 3895** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3896** SQLITE_TEXT. 3897*/ 3898#define SQLITE_INTEGER 1 3899#define SQLITE_FLOAT 2 3900#define SQLITE_BLOB 4 3901#define SQLITE_NULL 5 3902#ifdef SQLITE_TEXT 3903# undef SQLITE_TEXT 3904#else 3905# define SQLITE_TEXT 3 3906#endif 3907#define SQLITE3_TEXT 3 3908 3909/* 3910** CAPI3REF: Result Values From A Query 3911** KEYWORDS: {column access functions} 3912** METHOD: sqlite3_stmt 3913** 3914** ^These routines return information about a single column of the current 3915** result row of a query. ^In every case the first argument is a pointer 3916** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3917** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3918** and the second argument is the index of the column for which information 3919** should be returned. ^The leftmost column of the result set has the index 0. 3920** ^The number of columns in the result can be determined using 3921** [sqlite3_column_count()]. 3922** 3923** If the SQL statement does not currently point to a valid row, or if the 3924** column index is out of range, the result is undefined. 3925** These routines may only be called when the most recent call to 3926** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3927** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3928** If any of these routines are called after [sqlite3_reset()] or 3929** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3930** something other than [SQLITE_ROW], the results are undefined. 3931** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3932** are called from a different thread while any of these routines 3933** are pending, then the results are undefined. 3934** 3935** ^The sqlite3_column_type() routine returns the 3936** [SQLITE_INTEGER | datatype code] for the initial data type 3937** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3938** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3939** returned by sqlite3_column_type() is only meaningful if no type 3940** conversions have occurred as described below. After a type conversion, 3941** the value returned by sqlite3_column_type() is undefined. Future 3942** versions of SQLite may change the behavior of sqlite3_column_type() 3943** following a type conversion. 3944** 3945** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3946** routine returns the number of bytes in that BLOB or string. 3947** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3948** the string to UTF-8 and then returns the number of bytes. 3949** ^If the result is a numeric value then sqlite3_column_bytes() uses 3950** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3951** the number of bytes in that string. 3952** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3953** 3954** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3955** routine returns the number of bytes in that BLOB or string. 3956** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3957** the string to UTF-16 and then returns the number of bytes. 3958** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3959** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3960** the number of bytes in that string. 3961** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3962** 3963** ^The values returned by [sqlite3_column_bytes()] and 3964** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3965** of the string. ^For clarity: the values returned by 3966** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3967** bytes in the string, not the number of characters. 3968** 3969** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3970** even empty strings, are always zero-terminated. ^The return 3971** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3972** 3973** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 3974** [unprotected sqlite3_value] object. In a multithreaded environment, 3975** an unprotected sqlite3_value object may only be used safely with 3976** [sqlite3_bind_value()] and [sqlite3_result_value()]. 3977** If the [unprotected sqlite3_value] object returned by 3978** [sqlite3_column_value()] is used in any other way, including calls 3979** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3980** or [sqlite3_value_bytes()], the behavior is not threadsafe. 3981** 3982** These routines attempt to convert the value where appropriate. ^For 3983** example, if the internal representation is FLOAT and a text result 3984** is requested, [sqlite3_snprintf()] is used internally to perform the 3985** conversion automatically. ^(The following table details the conversions 3986** that are applied: 3987** 3988** <blockquote> 3989** <table border="1"> 3990** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3991** 3992** <tr><td> NULL <td> INTEGER <td> Result is 0 3993** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3994** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 3995** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 3996** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3997** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3998** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3999** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4000** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4001** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4002** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4003** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4004** <tr><td> TEXT <td> BLOB <td> No change 4005** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4006** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4007** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4008** </table> 4009** </blockquote>)^ 4010** 4011** Note that when type conversions occur, pointers returned by prior 4012** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4013** sqlite3_column_text16() may be invalidated. 4014** Type conversions and pointer invalidations might occur 4015** in the following cases: 4016** 4017** <ul> 4018** <li> The initial content is a BLOB and sqlite3_column_text() or 4019** sqlite3_column_text16() is called. A zero-terminator might 4020** need to be added to the string.</li> 4021** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4022** sqlite3_column_text16() is called. The content must be converted 4023** to UTF-16.</li> 4024** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4025** sqlite3_column_text() is called. The content must be converted 4026** to UTF-8.</li> 4027** </ul> 4028** 4029** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4030** not invalidate a prior pointer, though of course the content of the buffer 4031** that the prior pointer references will have been modified. Other kinds 4032** of conversion are done in place when it is possible, but sometimes they 4033** are not possible and in those cases prior pointers are invalidated. 4034** 4035** The safest policy is to invoke these routines 4036** in one of the following ways: 4037** 4038** <ul> 4039** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4040** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4041** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4042** </ul> 4043** 4044** In other words, you should call sqlite3_column_text(), 4045** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4046** into the desired format, then invoke sqlite3_column_bytes() or 4047** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4048** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4049** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4050** with calls to sqlite3_column_bytes(). 4051** 4052** ^The pointers returned are valid until a type conversion occurs as 4053** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4054** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4055** and BLOBs is freed automatically. Do <em>not</em> pass the pointers returned 4056** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4057** [sqlite3_free()]. 4058** 4059** ^(If a memory allocation error occurs during the evaluation of any 4060** of these routines, a default value is returned. The default value 4061** is either the integer 0, the floating point number 0.0, or a NULL 4062** pointer. Subsequent calls to [sqlite3_errcode()] will return 4063** [SQLITE_NOMEM].)^ 4064*/ 4065const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4066int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4067int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4068double sqlite3_column_double(sqlite3_stmt*, int iCol); 4069int sqlite3_column_int(sqlite3_stmt*, int iCol); 4070sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4071const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4072const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4073int sqlite3_column_type(sqlite3_stmt*, int iCol); 4074sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4075 4076/* 4077** CAPI3REF: Destroy A Prepared Statement Object 4078** DESTRUCTOR: sqlite3_stmt 4079** 4080** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4081** ^If the most recent evaluation of the statement encountered no errors 4082** or if the statement is never been evaluated, then sqlite3_finalize() returns 4083** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4084** sqlite3_finalize(S) returns the appropriate [error code] or 4085** [extended error code]. 4086** 4087** ^The sqlite3_finalize(S) routine can be called at any point during 4088** the life cycle of [prepared statement] S: 4089** before statement S is ever evaluated, after 4090** one or more calls to [sqlite3_reset()], or after any call 4091** to [sqlite3_step()] regardless of whether or not the statement has 4092** completed execution. 4093** 4094** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4095** 4096** The application must finalize every [prepared statement] in order to avoid 4097** resource leaks. It is a grievous error for the application to try to use 4098** a prepared statement after it has been finalized. Any use of a prepared 4099** statement after it has been finalized can result in undefined and 4100** undesirable behavior such as segfaults and heap corruption. 4101*/ 4102int sqlite3_finalize(sqlite3_stmt *pStmt); 4103 4104/* 4105** CAPI3REF: Reset A Prepared Statement Object 4106** METHOD: sqlite3_stmt 4107** 4108** The sqlite3_reset() function is called to reset a [prepared statement] 4109** object back to its initial state, ready to be re-executed. 4110** ^Any SQL statement variables that had values bound to them using 4111** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4112** Use [sqlite3_clear_bindings()] to reset the bindings. 4113** 4114** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4115** back to the beginning of its program. 4116** 4117** ^If the most recent call to [sqlite3_step(S)] for the 4118** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4119** or if [sqlite3_step(S)] has never before been called on S, 4120** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4121** 4122** ^If the most recent call to [sqlite3_step(S)] for the 4123** [prepared statement] S indicated an error, then 4124** [sqlite3_reset(S)] returns an appropriate [error code]. 4125** 4126** ^The [sqlite3_reset(S)] interface does not change the values 4127** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4128*/ 4129int sqlite3_reset(sqlite3_stmt *pStmt); 4130 4131/* 4132** CAPI3REF: Create Or Redefine SQL Functions 4133** KEYWORDS: {function creation routines} 4134** KEYWORDS: {application-defined SQL function} 4135** KEYWORDS: {application-defined SQL functions} 4136** METHOD: sqlite3 4137** 4138** ^These functions (collectively known as "function creation routines") 4139** are used to add SQL functions or aggregates or to redefine the behavior 4140** of existing SQL functions or aggregates. The only differences between 4141** these routines are the text encoding expected for 4142** the second parameter (the name of the function being created) 4143** and the presence or absence of a destructor callback for 4144** the application data pointer. 4145** 4146** ^The first parameter is the [database connection] to which the SQL 4147** function is to be added. ^If an application uses more than one database 4148** connection then application-defined SQL functions must be added 4149** to each database connection separately. 4150** 4151** ^The second parameter is the name of the SQL function to be created or 4152** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4153** representation, exclusive of the zero-terminator. ^Note that the name 4154** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4155** ^Any attempt to create a function with a longer name 4156** will result in [SQLITE_MISUSE] being returned. 4157** 4158** ^The third parameter (nArg) 4159** is the number of arguments that the SQL function or 4160** aggregate takes. ^If this parameter is -1, then the SQL function or 4161** aggregate may take any number of arguments between 0 and the limit 4162** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4163** parameter is less than -1 or greater than 127 then the behavior is 4164** undefined. 4165** 4166** ^The fourth parameter, eTextRep, specifies what 4167** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4168** its parameters. The application should set this parameter to 4169** [SQLITE_UTF16LE] if the function implementation invokes 4170** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4171** implementation invokes [sqlite3_value_text16be()] on an input, or 4172** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4173** otherwise. ^The same SQL function may be registered multiple times using 4174** different preferred text encodings, with different implementations for 4175** each encoding. 4176** ^When multiple implementations of the same function are available, SQLite 4177** will pick the one that involves the least amount of data conversion. 4178** 4179** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4180** to signal that the function will always return the same result given 4181** the same inputs within a single SQL statement. Most SQL functions are 4182** deterministic. The built-in [random()] SQL function is an example of a 4183** function that is not deterministic. The SQLite query planner is able to 4184** perform additional optimizations on deterministic functions, so use 4185** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4186** 4187** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4188** function can gain access to this pointer using [sqlite3_user_data()].)^ 4189** 4190** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4191** pointers to C-language functions that implement the SQL function or 4192** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4193** callback only; NULL pointers must be passed as the xStep and xFinal 4194** parameters. ^An aggregate SQL function requires an implementation of xStep 4195** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4196** SQL function or aggregate, pass NULL pointers for all three function 4197** callbacks. 4198** 4199** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4200** then it is destructor for the application data pointer. 4201** The destructor is invoked when the function is deleted, either by being 4202** overloaded or when the database connection closes.)^ 4203** ^The destructor is also invoked if the call to 4204** sqlite3_create_function_v2() fails. 4205** ^When the destructor callback of the tenth parameter is invoked, it 4206** is passed a single argument which is a copy of the application data 4207** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4208** 4209** ^It is permitted to register multiple implementations of the same 4210** functions with the same name but with either differing numbers of 4211** arguments or differing preferred text encodings. ^SQLite will use 4212** the implementation that most closely matches the way in which the 4213** SQL function is used. ^A function implementation with a non-negative 4214** nArg parameter is a better match than a function implementation with 4215** a negative nArg. ^A function where the preferred text encoding 4216** matches the database encoding is a better 4217** match than a function where the encoding is different. 4218** ^A function where the encoding difference is between UTF16le and UTF16be 4219** is a closer match than a function where the encoding difference is 4220** between UTF8 and UTF16. 4221** 4222** ^Built-in functions may be overloaded by new application-defined functions. 4223** 4224** ^An application-defined function is permitted to call other 4225** SQLite interfaces. However, such calls must not 4226** close the database connection nor finalize or reset the prepared 4227** statement in which the function is running. 4228*/ 4229int sqlite3_create_function( 4230 sqlite3 *db, 4231 const char *zFunctionName, 4232 int nArg, 4233 int eTextRep, 4234 void *pApp, 4235 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4236 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4237 void (*xFinal)(sqlite3_context*) 4238); 4239int sqlite3_create_function16( 4240 sqlite3 *db, 4241 const void *zFunctionName, 4242 int nArg, 4243 int eTextRep, 4244 void *pApp, 4245 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4246 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4247 void (*xFinal)(sqlite3_context*) 4248); 4249int sqlite3_create_function_v2( 4250 sqlite3 *db, 4251 const char *zFunctionName, 4252 int nArg, 4253 int eTextRep, 4254 void *pApp, 4255 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4256 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4257 void (*xFinal)(sqlite3_context*), 4258 void(*xDestroy)(void*) 4259); 4260 4261/* 4262** CAPI3REF: Text Encodings 4263** 4264** These constant define integer codes that represent the various 4265** text encodings supported by SQLite. 4266*/ 4267#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4268#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4269#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4270#define SQLITE_UTF16 4 /* Use native byte order */ 4271#define SQLITE_ANY 5 /* Deprecated */ 4272#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4273 4274/* 4275** CAPI3REF: Function Flags 4276** 4277** These constants may be ORed together with the 4278** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4279** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4280** [sqlite3_create_function_v2()]. 4281*/ 4282#define SQLITE_DETERMINISTIC 0x800 4283 4284/* 4285** CAPI3REF: Deprecated Functions 4286** DEPRECATED 4287** 4288** These functions are [deprecated]. In order to maintain 4289** backwards compatibility with older code, these functions continue 4290** to be supported. However, new applications should avoid 4291** the use of these functions. To encourage programmers to avoid 4292** these functions, we will not explain what they do. 4293*/ 4294#ifndef SQLITE_OMIT_DEPRECATED 4295SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4296SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4297SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4298SQLITE_DEPRECATED int sqlite3_global_recover(void); 4299SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4300SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4301 void*,sqlite3_int64); 4302#endif 4303 4304/* 4305** CAPI3REF: Obtaining SQL Values 4306** METHOD: sqlite3_value 4307** 4308** The C-language implementation of SQL functions and aggregates uses 4309** this set of interface routines to access the parameter values on 4310** the function or aggregate. 4311** 4312** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4313** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4314** define callbacks that implement the SQL functions and aggregates. 4315** The 3rd parameter to these callbacks is an array of pointers to 4316** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4317** each parameter to the SQL function. These routines are used to 4318** extract values from the [sqlite3_value] objects. 4319** 4320** These routines work only with [protected sqlite3_value] objects. 4321** Any attempt to use these routines on an [unprotected sqlite3_value] 4322** object results in undefined behavior. 4323** 4324** ^These routines work just like the corresponding [column access functions] 4325** except that these routines take a single [protected sqlite3_value] object 4326** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4327** 4328** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4329** in the native byte-order of the host machine. ^The 4330** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4331** extract UTF-16 strings as big-endian and little-endian respectively. 4332** 4333** ^(The sqlite3_value_numeric_type() interface attempts to apply 4334** numeric affinity to the value. This means that an attempt is 4335** made to convert the value to an integer or floating point. If 4336** such a conversion is possible without loss of information (in other 4337** words, if the value is a string that looks like a number) 4338** then the conversion is performed. Otherwise no conversion occurs. 4339** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4340** 4341** Please pay particular attention to the fact that the pointer returned 4342** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4343** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4344** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4345** or [sqlite3_value_text16()]. 4346** 4347** These routines must be called from the same thread as 4348** the SQL function that supplied the [sqlite3_value*] parameters. 4349*/ 4350const void *sqlite3_value_blob(sqlite3_value*); 4351int sqlite3_value_bytes(sqlite3_value*); 4352int sqlite3_value_bytes16(sqlite3_value*); 4353double sqlite3_value_double(sqlite3_value*); 4354int sqlite3_value_int(sqlite3_value*); 4355sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4356const unsigned char *sqlite3_value_text(sqlite3_value*); 4357const void *sqlite3_value_text16(sqlite3_value*); 4358const void *sqlite3_value_text16le(sqlite3_value*); 4359const void *sqlite3_value_text16be(sqlite3_value*); 4360int sqlite3_value_type(sqlite3_value*); 4361int sqlite3_value_numeric_type(sqlite3_value*); 4362 4363/* 4364** CAPI3REF: Finding The Subtype Of SQL Values 4365** METHOD: sqlite3_value 4366** 4367** The sqlite3_value_subtype(V) function returns the subtype for 4368** an [application-defined SQL function] argument V. The subtype 4369** information can be used to pass a limited amount of context from 4370** one SQL function to another. Use the [sqlite3_result_subtype()] 4371** routine to set the subtype for the return value of an SQL function. 4372** 4373** SQLite makes no use of subtype itself. It merely passes the subtype 4374** from the result of one [application-defined SQL function] into the 4375** input of another. 4376*/ 4377unsigned int sqlite3_value_subtype(sqlite3_value*); 4378 4379/* 4380** CAPI3REF: Copy And Free SQL Values 4381** METHOD: sqlite3_value 4382** 4383** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4384** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4385** is a [protected sqlite3_value] object even if the input is not. 4386** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4387** memory allocation fails. 4388** 4389** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4390** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4391** then sqlite3_value_free(V) is a harmless no-op. 4392*/ 4393SQLITE_EXPERIMENTAL sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4394SQLITE_EXPERIMENTAL void sqlite3_value_free(sqlite3_value*); 4395 4396/* 4397** CAPI3REF: Obtain Aggregate Function Context 4398** METHOD: sqlite3_context 4399** 4400** Implementations of aggregate SQL functions use this 4401** routine to allocate memory for storing their state. 4402** 4403** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4404** for a particular aggregate function, SQLite 4405** allocates N of memory, zeroes out that memory, and returns a pointer 4406** to the new memory. ^On second and subsequent calls to 4407** sqlite3_aggregate_context() for the same aggregate function instance, 4408** the same buffer is returned. Sqlite3_aggregate_context() is normally 4409** called once for each invocation of the xStep callback and then one 4410** last time when the xFinal callback is invoked. ^(When no rows match 4411** an aggregate query, the xStep() callback of the aggregate function 4412** implementation is never called and xFinal() is called exactly once. 4413** In those cases, sqlite3_aggregate_context() might be called for the 4414** first time from within xFinal().)^ 4415** 4416** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4417** when first called if N is less than or equal to zero or if a memory 4418** allocate error occurs. 4419** 4420** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4421** determined by the N parameter on first successful call. Changing the 4422** value of N in subsequent call to sqlite3_aggregate_context() within 4423** the same aggregate function instance will not resize the memory 4424** allocation.)^ Within the xFinal callback, it is customary to set 4425** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4426** pointless memory allocations occur. 4427** 4428** ^SQLite automatically frees the memory allocated by 4429** sqlite3_aggregate_context() when the aggregate query concludes. 4430** 4431** The first parameter must be a copy of the 4432** [sqlite3_context | SQL function context] that is the first parameter 4433** to the xStep or xFinal callback routine that implements the aggregate 4434** function. 4435** 4436** This routine must be called from the same thread in which 4437** the aggregate SQL function is running. 4438*/ 4439void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4440 4441/* 4442** CAPI3REF: User Data For Functions 4443** METHOD: sqlite3_context 4444** 4445** ^The sqlite3_user_data() interface returns a copy of 4446** the pointer that was the pUserData parameter (the 5th parameter) 4447** of the [sqlite3_create_function()] 4448** and [sqlite3_create_function16()] routines that originally 4449** registered the application defined function. 4450** 4451** This routine must be called from the same thread in which 4452** the application-defined function is running. 4453*/ 4454void *sqlite3_user_data(sqlite3_context*); 4455 4456/* 4457** CAPI3REF: Database Connection For Functions 4458** METHOD: sqlite3_context 4459** 4460** ^The sqlite3_context_db_handle() interface returns a copy of 4461** the pointer to the [database connection] (the 1st parameter) 4462** of the [sqlite3_create_function()] 4463** and [sqlite3_create_function16()] routines that originally 4464** registered the application defined function. 4465*/ 4466sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4467 4468/* 4469** CAPI3REF: Function Auxiliary Data 4470** METHOD: sqlite3_context 4471** 4472** These functions may be used by (non-aggregate) SQL functions to 4473** associate metadata with argument values. If the same value is passed to 4474** multiple invocations of the same SQL function during query execution, under 4475** some circumstances the associated metadata may be preserved. An example 4476** of where this might be useful is in a regular-expression matching 4477** function. The compiled version of the regular expression can be stored as 4478** metadata associated with the pattern string. 4479** Then as long as the pattern string remains the same, 4480** the compiled regular expression can be reused on multiple 4481** invocations of the same function. 4482** 4483** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4484** associated by the sqlite3_set_auxdata() function with the Nth argument 4485** value to the application-defined function. ^If there is no metadata 4486** associated with the function argument, this sqlite3_get_auxdata() interface 4487** returns a NULL pointer. 4488** 4489** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4490** argument of the application-defined function. ^Subsequent 4491** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4492** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4493** NULL if the metadata has been discarded. 4494** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4495** SQLite will invoke the destructor function X with parameter P exactly 4496** once, when the metadata is discarded. 4497** SQLite is free to discard the metadata at any time, including: <ul> 4498** <li> when the corresponding function parameter changes, or 4499** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4500** SQL statement, or 4501** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or 4502** <li> during the original sqlite3_set_auxdata() call when a memory 4503** allocation error occurs. </ul>)^ 4504** 4505** Note the last bullet in particular. The destructor X in 4506** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4507** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4508** should be called near the end of the function implementation and the 4509** function implementation should not make any use of P after 4510** sqlite3_set_auxdata() has been called. 4511** 4512** ^(In practice, metadata is preserved between function calls for 4513** function parameters that are compile-time constants, including literal 4514** values and [parameters] and expressions composed from the same.)^ 4515** 4516** These routines must be called from the same thread in which 4517** the SQL function is running. 4518*/ 4519void *sqlite3_get_auxdata(sqlite3_context*, int N); 4520void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4521 4522 4523/* 4524** CAPI3REF: Constants Defining Special Destructor Behavior 4525** 4526** These are special values for the destructor that is passed in as the 4527** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4528** argument is SQLITE_STATIC, it means that the content pointer is constant 4529** and will never change. It does not need to be destroyed. ^The 4530** SQLITE_TRANSIENT value means that the content will likely change in 4531** the near future and that SQLite should make its own private copy of 4532** the content before returning. 4533** 4534** The typedef is necessary to work around problems in certain 4535** C++ compilers. 4536*/ 4537typedef void (*sqlite3_destructor_type)(void*); 4538#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4539#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4540 4541/* 4542** CAPI3REF: Setting The Result Of An SQL Function 4543** METHOD: sqlite3_context 4544** 4545** These routines are used by the xFunc or xFinal callbacks that 4546** implement SQL functions and aggregates. See 4547** [sqlite3_create_function()] and [sqlite3_create_function16()] 4548** for additional information. 4549** 4550** These functions work very much like the [parameter binding] family of 4551** functions used to bind values to host parameters in prepared statements. 4552** Refer to the [SQL parameter] documentation for additional information. 4553** 4554** ^The sqlite3_result_blob() interface sets the result from 4555** an application-defined function to be the BLOB whose content is pointed 4556** to by the second parameter and which is N bytes long where N is the 4557** third parameter. 4558** 4559** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 4560** interfaces set the result of the application-defined function to be 4561** a BLOB containing all zero bytes and N bytes in size. 4562** 4563** ^The sqlite3_result_double() interface sets the result from 4564** an application-defined function to be a floating point value specified 4565** by its 2nd argument. 4566** 4567** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4568** cause the implemented SQL function to throw an exception. 4569** ^SQLite uses the string pointed to by the 4570** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4571** as the text of an error message. ^SQLite interprets the error 4572** message string from sqlite3_result_error() as UTF-8. ^SQLite 4573** interprets the string from sqlite3_result_error16() as UTF-16 in native 4574** byte order. ^If the third parameter to sqlite3_result_error() 4575** or sqlite3_result_error16() is negative then SQLite takes as the error 4576** message all text up through the first zero character. 4577** ^If the third parameter to sqlite3_result_error() or 4578** sqlite3_result_error16() is non-negative then SQLite takes that many 4579** bytes (not characters) from the 2nd parameter as the error message. 4580** ^The sqlite3_result_error() and sqlite3_result_error16() 4581** routines make a private copy of the error message text before 4582** they return. Hence, the calling function can deallocate or 4583** modify the text after they return without harm. 4584** ^The sqlite3_result_error_code() function changes the error code 4585** returned by SQLite as a result of an error in a function. ^By default, 4586** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4587** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4588** 4589** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4590** error indicating that a string or BLOB is too long to represent. 4591** 4592** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4593** error indicating that a memory allocation failed. 4594** 4595** ^The sqlite3_result_int() interface sets the return value 4596** of the application-defined function to be the 32-bit signed integer 4597** value given in the 2nd argument. 4598** ^The sqlite3_result_int64() interface sets the return value 4599** of the application-defined function to be the 64-bit signed integer 4600** value given in the 2nd argument. 4601** 4602** ^The sqlite3_result_null() interface sets the return value 4603** of the application-defined function to be NULL. 4604** 4605** ^The sqlite3_result_text(), sqlite3_result_text16(), 4606** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4607** set the return value of the application-defined function to be 4608** a text string which is represented as UTF-8, UTF-16 native byte order, 4609** UTF-16 little endian, or UTF-16 big endian, respectively. 4610** ^The sqlite3_result_text64() interface sets the return value of an 4611** application-defined function to be a text string in an encoding 4612** specified by the fifth (and last) parameter, which must be one 4613** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 4614** ^SQLite takes the text result from the application from 4615** the 2nd parameter of the sqlite3_result_text* interfaces. 4616** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4617** is negative, then SQLite takes result text from the 2nd parameter 4618** through the first zero character. 4619** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4620** is non-negative, then as many bytes (not characters) of the text 4621** pointed to by the 2nd parameter are taken as the application-defined 4622** function result. If the 3rd parameter is non-negative, then it 4623** must be the byte offset into the string where the NUL terminator would 4624** appear if the string where NUL terminated. If any NUL characters occur 4625** in the string at a byte offset that is less than the value of the 3rd 4626** parameter, then the resulting string will contain embedded NULs and the 4627** result of expressions operating on strings with embedded NULs is undefined. 4628** ^If the 4th parameter to the sqlite3_result_text* interfaces 4629** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4630** function as the destructor on the text or BLOB result when it has 4631** finished using that result. 4632** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4633** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4634** assumes that the text or BLOB result is in constant space and does not 4635** copy the content of the parameter nor call a destructor on the content 4636** when it has finished using that result. 4637** ^If the 4th parameter to the sqlite3_result_text* interfaces 4638** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4639** then SQLite makes a copy of the result into space obtained from 4640** from [sqlite3_malloc()] before it returns. 4641** 4642** ^The sqlite3_result_value() interface sets the result of 4643** the application-defined function to be a copy of the 4644** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4645** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4646** so that the [sqlite3_value] specified in the parameter may change or 4647** be deallocated after sqlite3_result_value() returns without harm. 4648** ^A [protected sqlite3_value] object may always be used where an 4649** [unprotected sqlite3_value] object is required, so either 4650** kind of [sqlite3_value] object can be used with this interface. 4651** 4652** If these routines are called from within the different thread 4653** than the one containing the application-defined function that received 4654** the [sqlite3_context] pointer, the results are undefined. 4655*/ 4656void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4657void sqlite3_result_blob64(sqlite3_context*,const void*, 4658 sqlite3_uint64,void(*)(void*)); 4659void sqlite3_result_double(sqlite3_context*, double); 4660void sqlite3_result_error(sqlite3_context*, const char*, int); 4661void sqlite3_result_error16(sqlite3_context*, const void*, int); 4662void sqlite3_result_error_toobig(sqlite3_context*); 4663void sqlite3_result_error_nomem(sqlite3_context*); 4664void sqlite3_result_error_code(sqlite3_context*, int); 4665void sqlite3_result_int(sqlite3_context*, int); 4666void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4667void sqlite3_result_null(sqlite3_context*); 4668void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4669void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 4670 void(*)(void*), unsigned char encoding); 4671void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4672void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4673void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4674void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4675void sqlite3_result_zeroblob(sqlite3_context*, int n); 4676int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 4677 4678 4679/* 4680** CAPI3REF: Setting The Subtype Of An SQL Function 4681** METHOD: sqlite3_context 4682** 4683** The sqlite3_result_subtype(C,T) function causes the subtype of 4684** the result from the [application-defined SQL function] with 4685** [sqlite3_context] C to be the value T. Only the lower 8 bits 4686** of the subtype T are preserved in current versions of SQLite; 4687** higher order bits are discarded. 4688** The number of subtype bytes preserved by SQLite might increase 4689** in future releases of SQLite. 4690*/ 4691void sqlite3_result_subtype(sqlite3_context*,unsigned int); 4692 4693/* 4694** CAPI3REF: Define New Collating Sequences 4695** METHOD: sqlite3 4696** 4697** ^These functions add, remove, or modify a [collation] associated 4698** with the [database connection] specified as the first argument. 4699** 4700** ^The name of the collation is a UTF-8 string 4701** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4702** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4703** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4704** considered to be the same name. 4705** 4706** ^(The third argument (eTextRep) must be one of the constants: 4707** <ul> 4708** <li> [SQLITE_UTF8], 4709** <li> [SQLITE_UTF16LE], 4710** <li> [SQLITE_UTF16BE], 4711** <li> [SQLITE_UTF16], or 4712** <li> [SQLITE_UTF16_ALIGNED]. 4713** </ul>)^ 4714** ^The eTextRep argument determines the encoding of strings passed 4715** to the collating function callback, xCallback. 4716** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4717** force strings to be UTF16 with native byte order. 4718** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4719** on an even byte address. 4720** 4721** ^The fourth argument, pArg, is an application data pointer that is passed 4722** through as the first argument to the collating function callback. 4723** 4724** ^The fifth argument, xCallback, is a pointer to the collating function. 4725** ^Multiple collating functions can be registered using the same name but 4726** with different eTextRep parameters and SQLite will use whichever 4727** function requires the least amount of data transformation. 4728** ^If the xCallback argument is NULL then the collating function is 4729** deleted. ^When all collating functions having the same name are deleted, 4730** that collation is no longer usable. 4731** 4732** ^The collating function callback is invoked with a copy of the pArg 4733** application data pointer and with two strings in the encoding specified 4734** by the eTextRep argument. The collating function must return an 4735** integer that is negative, zero, or positive 4736** if the first string is less than, equal to, or greater than the second, 4737** respectively. A collating function must always return the same answer 4738** given the same inputs. If two or more collating functions are registered 4739** to the same collation name (using different eTextRep values) then all 4740** must give an equivalent answer when invoked with equivalent strings. 4741** The collating function must obey the following properties for all 4742** strings A, B, and C: 4743** 4744** <ol> 4745** <li> If A==B then B==A. 4746** <li> If A==B and B==C then A==C. 4747** <li> If A<B THEN B>A. 4748** <li> If A<B and B<C then A<C. 4749** </ol> 4750** 4751** If a collating function fails any of the above constraints and that 4752** collating function is registered and used, then the behavior of SQLite 4753** is undefined. 4754** 4755** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4756** with the addition that the xDestroy callback is invoked on pArg when 4757** the collating function is deleted. 4758** ^Collating functions are deleted when they are overridden by later 4759** calls to the collation creation functions or when the 4760** [database connection] is closed using [sqlite3_close()]. 4761** 4762** ^The xDestroy callback is <u>not</u> called if the 4763** sqlite3_create_collation_v2() function fails. Applications that invoke 4764** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4765** check the return code and dispose of the application data pointer 4766** themselves rather than expecting SQLite to deal with it for them. 4767** This is different from every other SQLite interface. The inconsistency 4768** is unfortunate but cannot be changed without breaking backwards 4769** compatibility. 4770** 4771** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4772*/ 4773int sqlite3_create_collation( 4774 sqlite3*, 4775 const char *zName, 4776 int eTextRep, 4777 void *pArg, 4778 int(*xCompare)(void*,int,const void*,int,const void*) 4779); 4780int sqlite3_create_collation_v2( 4781 sqlite3*, 4782 const char *zName, 4783 int eTextRep, 4784 void *pArg, 4785 int(*xCompare)(void*,int,const void*,int,const void*), 4786 void(*xDestroy)(void*) 4787); 4788int sqlite3_create_collation16( 4789 sqlite3*, 4790 const void *zName, 4791 int eTextRep, 4792 void *pArg, 4793 int(*xCompare)(void*,int,const void*,int,const void*) 4794); 4795 4796/* 4797** CAPI3REF: Collation Needed Callbacks 4798** METHOD: sqlite3 4799** 4800** ^To avoid having to register all collation sequences before a database 4801** can be used, a single callback function may be registered with the 4802** [database connection] to be invoked whenever an undefined collation 4803** sequence is required. 4804** 4805** ^If the function is registered using the sqlite3_collation_needed() API, 4806** then it is passed the names of undefined collation sequences as strings 4807** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4808** the names are passed as UTF-16 in machine native byte order. 4809** ^A call to either function replaces the existing collation-needed callback. 4810** 4811** ^(When the callback is invoked, the first argument passed is a copy 4812** of the second argument to sqlite3_collation_needed() or 4813** sqlite3_collation_needed16(). The second argument is the database 4814** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4815** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4816** sequence function required. The fourth parameter is the name of the 4817** required collation sequence.)^ 4818** 4819** The callback function should register the desired collation using 4820** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4821** [sqlite3_create_collation_v2()]. 4822*/ 4823int sqlite3_collation_needed( 4824 sqlite3*, 4825 void*, 4826 void(*)(void*,sqlite3*,int eTextRep,const char*) 4827); 4828int sqlite3_collation_needed16( 4829 sqlite3*, 4830 void*, 4831 void(*)(void*,sqlite3*,int eTextRep,const void*) 4832); 4833 4834#ifdef SQLITE_HAS_CODEC 4835/* 4836** Specify the key for an encrypted database. This routine should be 4837** called right after sqlite3_open(). 4838** 4839** The code to implement this API is not available in the public release 4840** of SQLite. 4841*/ 4842int sqlite3_key( 4843 sqlite3 *db, /* Database to be rekeyed */ 4844 const void *pKey, int nKey /* The key */ 4845); 4846int sqlite3_key_v2( 4847 sqlite3 *db, /* Database to be rekeyed */ 4848 const char *zDbName, /* Name of the database */ 4849 const void *pKey, int nKey /* The key */ 4850); 4851 4852/* 4853** Change the key on an open database. If the current database is not 4854** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4855** database is decrypted. 4856** 4857** The code to implement this API is not available in the public release 4858** of SQLite. 4859*/ 4860int sqlite3_rekey( 4861 sqlite3 *db, /* Database to be rekeyed */ 4862 const void *pKey, int nKey /* The new key */ 4863); 4864int sqlite3_rekey_v2( 4865 sqlite3 *db, /* Database to be rekeyed */ 4866 const char *zDbName, /* Name of the database */ 4867 const void *pKey, int nKey /* The new key */ 4868); 4869 4870/* 4871** Specify the activation key for a SEE database. Unless 4872** activated, none of the SEE routines will work. 4873*/ 4874void sqlite3_activate_see( 4875 const char *zPassPhrase /* Activation phrase */ 4876); 4877#endif 4878 4879#ifdef SQLITE_ENABLE_CEROD 4880/* 4881** Specify the activation key for a CEROD database. Unless 4882** activated, none of the CEROD routines will work. 4883*/ 4884void sqlite3_activate_cerod( 4885 const char *zPassPhrase /* Activation phrase */ 4886); 4887#endif 4888 4889/* 4890** CAPI3REF: Suspend Execution For A Short Time 4891** 4892** The sqlite3_sleep() function causes the current thread to suspend execution 4893** for at least a number of milliseconds specified in its parameter. 4894** 4895** If the operating system does not support sleep requests with 4896** millisecond time resolution, then the time will be rounded up to 4897** the nearest second. The number of milliseconds of sleep actually 4898** requested from the operating system is returned. 4899** 4900** ^SQLite implements this interface by calling the xSleep() 4901** method of the default [sqlite3_vfs] object. If the xSleep() method 4902** of the default VFS is not implemented correctly, or not implemented at 4903** all, then the behavior of sqlite3_sleep() may deviate from the description 4904** in the previous paragraphs. 4905*/ 4906int sqlite3_sleep(int); 4907 4908/* 4909** CAPI3REF: Name Of The Folder Holding Temporary Files 4910** 4911** ^(If this global variable is made to point to a string which is 4912** the name of a folder (a.k.a. directory), then all temporary files 4913** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4914** will be placed in that directory.)^ ^If this variable 4915** is a NULL pointer, then SQLite performs a search for an appropriate 4916** temporary file directory. 4917** 4918** Applications are strongly discouraged from using this global variable. 4919** It is required to set a temporary folder on Windows Runtime (WinRT). 4920** But for all other platforms, it is highly recommended that applications 4921** neither read nor write this variable. This global variable is a relic 4922** that exists for backwards compatibility of legacy applications and should 4923** be avoided in new projects. 4924** 4925** It is not safe to read or modify this variable in more than one 4926** thread at a time. It is not safe to read or modify this variable 4927** if a [database connection] is being used at the same time in a separate 4928** thread. 4929** It is intended that this variable be set once 4930** as part of process initialization and before any SQLite interface 4931** routines have been called and that this variable remain unchanged 4932** thereafter. 4933** 4934** ^The [temp_store_directory pragma] may modify this variable and cause 4935** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4936** the [temp_store_directory pragma] always assumes that any string 4937** that this variable points to is held in memory obtained from 4938** [sqlite3_malloc] and the pragma may attempt to free that memory 4939** using [sqlite3_free]. 4940** Hence, if this variable is modified directly, either it should be 4941** made NULL or made to point to memory obtained from [sqlite3_malloc] 4942** or else the use of the [temp_store_directory pragma] should be avoided. 4943** Except when requested by the [temp_store_directory pragma], SQLite 4944** does not free the memory that sqlite3_temp_directory points to. If 4945** the application wants that memory to be freed, it must do 4946** so itself, taking care to only do so after all [database connection] 4947** objects have been destroyed. 4948** 4949** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4950** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4951** features that require the use of temporary files may fail. Here is an 4952** example of how to do this using C++ with the Windows Runtime: 4953** 4954** <blockquote><pre> 4955** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4956** TemporaryFolder->Path->Data(); 4957** char zPathBuf[MAX_PATH + 1]; 4958** memset(zPathBuf, 0, sizeof(zPathBuf)); 4959** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4960** NULL, NULL); 4961** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4962** </pre></blockquote> 4963*/ 4964SQLITE_EXTERN char *sqlite3_temp_directory; 4965 4966/* 4967** CAPI3REF: Name Of The Folder Holding Database Files 4968** 4969** ^(If this global variable is made to point to a string which is 4970** the name of a folder (a.k.a. directory), then all database files 4971** specified with a relative pathname and created or accessed by 4972** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4973** to be relative to that directory.)^ ^If this variable is a NULL 4974** pointer, then SQLite assumes that all database files specified 4975** with a relative pathname are relative to the current directory 4976** for the process. Only the windows VFS makes use of this global 4977** variable; it is ignored by the unix VFS. 4978** 4979** Changing the value of this variable while a database connection is 4980** open can result in a corrupt database. 4981** 4982** It is not safe to read or modify this variable in more than one 4983** thread at a time. It is not safe to read or modify this variable 4984** if a [database connection] is being used at the same time in a separate 4985** thread. 4986** It is intended that this variable be set once 4987** as part of process initialization and before any SQLite interface 4988** routines have been called and that this variable remain unchanged 4989** thereafter. 4990** 4991** ^The [data_store_directory pragma] may modify this variable and cause 4992** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4993** the [data_store_directory pragma] always assumes that any string 4994** that this variable points to is held in memory obtained from 4995** [sqlite3_malloc] and the pragma may attempt to free that memory 4996** using [sqlite3_free]. 4997** Hence, if this variable is modified directly, either it should be 4998** made NULL or made to point to memory obtained from [sqlite3_malloc] 4999** or else the use of the [data_store_directory pragma] should be avoided. 5000*/ 5001SQLITE_EXTERN char *sqlite3_data_directory; 5002 5003/* 5004** CAPI3REF: Test For Auto-Commit Mode 5005** KEYWORDS: {autocommit mode} 5006** METHOD: sqlite3 5007** 5008** ^The sqlite3_get_autocommit() interface returns non-zero or 5009** zero if the given database connection is or is not in autocommit mode, 5010** respectively. ^Autocommit mode is on by default. 5011** ^Autocommit mode is disabled by a [BEGIN] statement. 5012** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5013** 5014** If certain kinds of errors occur on a statement within a multi-statement 5015** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5016** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5017** transaction might be rolled back automatically. The only way to 5018** find out whether SQLite automatically rolled back the transaction after 5019** an error is to use this function. 5020** 5021** If another thread changes the autocommit status of the database 5022** connection while this routine is running, then the return value 5023** is undefined. 5024*/ 5025int sqlite3_get_autocommit(sqlite3*); 5026 5027/* 5028** CAPI3REF: Find The Database Handle Of A Prepared Statement 5029** METHOD: sqlite3_stmt 5030** 5031** ^The sqlite3_db_handle interface returns the [database connection] handle 5032** to which a [prepared statement] belongs. ^The [database connection] 5033** returned by sqlite3_db_handle is the same [database connection] 5034** that was the first argument 5035** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5036** create the statement in the first place. 5037*/ 5038sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5039 5040/* 5041** CAPI3REF: Return The Filename For A Database Connection 5042** METHOD: sqlite3 5043** 5044** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5045** associated with database N of connection D. ^The main database file 5046** has the name "main". If there is no attached database N on the database 5047** connection D, or if database N is a temporary or in-memory database, then 5048** a NULL pointer is returned. 5049** 5050** ^The filename returned by this function is the output of the 5051** xFullPathname method of the [VFS]. ^In other words, the filename 5052** will be an absolute pathname, even if the filename used 5053** to open the database originally was a URI or relative pathname. 5054*/ 5055const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5056 5057/* 5058** CAPI3REF: Determine if a database is read-only 5059** METHOD: sqlite3 5060** 5061** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5062** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5063** the name of a database on connection D. 5064*/ 5065int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5066 5067/* 5068** CAPI3REF: Find the next prepared statement 5069** METHOD: sqlite3 5070** 5071** ^This interface returns a pointer to the next [prepared statement] after 5072** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5073** then this interface returns a pointer to the first prepared statement 5074** associated with the database connection pDb. ^If no prepared statement 5075** satisfies the conditions of this routine, it returns NULL. 5076** 5077** The [database connection] pointer D in a call to 5078** [sqlite3_next_stmt(D,S)] must refer to an open database 5079** connection and in particular must not be a NULL pointer. 5080*/ 5081sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5082 5083/* 5084** CAPI3REF: Commit And Rollback Notification Callbacks 5085** METHOD: sqlite3 5086** 5087** ^The sqlite3_commit_hook() interface registers a callback 5088** function to be invoked whenever a transaction is [COMMIT | committed]. 5089** ^Any callback set by a previous call to sqlite3_commit_hook() 5090** for the same database connection is overridden. 5091** ^The sqlite3_rollback_hook() interface registers a callback 5092** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5093** ^Any callback set by a previous call to sqlite3_rollback_hook() 5094** for the same database connection is overridden. 5095** ^The pArg argument is passed through to the callback. 5096** ^If the callback on a commit hook function returns non-zero, 5097** then the commit is converted into a rollback. 5098** 5099** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5100** return the P argument from the previous call of the same function 5101** on the same [database connection] D, or NULL for 5102** the first call for each function on D. 5103** 5104** The commit and rollback hook callbacks are not reentrant. 5105** The callback implementation must not do anything that will modify 5106** the database connection that invoked the callback. Any actions 5107** to modify the database connection must be deferred until after the 5108** completion of the [sqlite3_step()] call that triggered the commit 5109** or rollback hook in the first place. 5110** Note that running any other SQL statements, including SELECT statements, 5111** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5112** the database connections for the meaning of "modify" in this paragraph. 5113** 5114** ^Registering a NULL function disables the callback. 5115** 5116** ^When the commit hook callback routine returns zero, the [COMMIT] 5117** operation is allowed to continue normally. ^If the commit hook 5118** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5119** ^The rollback hook is invoked on a rollback that results from a commit 5120** hook returning non-zero, just as it would be with any other rollback. 5121** 5122** ^For the purposes of this API, a transaction is said to have been 5123** rolled back if an explicit "ROLLBACK" statement is executed, or 5124** an error or constraint causes an implicit rollback to occur. 5125** ^The rollback callback is not invoked if a transaction is 5126** automatically rolled back because the database connection is closed. 5127** 5128** See also the [sqlite3_update_hook()] interface. 5129*/ 5130void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5131void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5132 5133/* 5134** CAPI3REF: Data Change Notification Callbacks 5135** METHOD: sqlite3 5136** 5137** ^The sqlite3_update_hook() interface registers a callback function 5138** with the [database connection] identified by the first argument 5139** to be invoked whenever a row is updated, inserted or deleted in 5140** a rowid table. 5141** ^Any callback set by a previous call to this function 5142** for the same database connection is overridden. 5143** 5144** ^The second argument is a pointer to the function to invoke when a 5145** row is updated, inserted or deleted in a rowid table. 5146** ^The first argument to the callback is a copy of the third argument 5147** to sqlite3_update_hook(). 5148** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5149** or [SQLITE_UPDATE], depending on the operation that caused the callback 5150** to be invoked. 5151** ^The third and fourth arguments to the callback contain pointers to the 5152** database and table name containing the affected row. 5153** ^The final callback parameter is the [rowid] of the row. 5154** ^In the case of an update, this is the [rowid] after the update takes place. 5155** 5156** ^(The update hook is not invoked when internal system tables are 5157** modified (i.e. sqlite_master and sqlite_sequence).)^ 5158** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5159** 5160** ^In the current implementation, the update hook 5161** is not invoked when duplication rows are deleted because of an 5162** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5163** invoked when rows are deleted using the [truncate optimization]. 5164** The exceptions defined in this paragraph might change in a future 5165** release of SQLite. 5166** 5167** The update hook implementation must not do anything that will modify 5168** the database connection that invoked the update hook. Any actions 5169** to modify the database connection must be deferred until after the 5170** completion of the [sqlite3_step()] call that triggered the update hook. 5171** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5172** database connections for the meaning of "modify" in this paragraph. 5173** 5174** ^The sqlite3_update_hook(D,C,P) function 5175** returns the P argument from the previous call 5176** on the same [database connection] D, or NULL for 5177** the first call on D. 5178** 5179** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 5180** interfaces. 5181*/ 5182void *sqlite3_update_hook( 5183 sqlite3*, 5184 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5185 void* 5186); 5187 5188/* 5189** CAPI3REF: Enable Or Disable Shared Pager Cache 5190** 5191** ^(This routine enables or disables the sharing of the database cache 5192** and schema data structures between [database connection | connections] 5193** to the same database. Sharing is enabled if the argument is true 5194** and disabled if the argument is false.)^ 5195** 5196** ^Cache sharing is enabled and disabled for an entire process. 5197** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 5198** sharing was enabled or disabled for each thread separately. 5199** 5200** ^(The cache sharing mode set by this interface effects all subsequent 5201** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5202** Existing database connections continue use the sharing mode 5203** that was in effect at the time they were opened.)^ 5204** 5205** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5206** successfully. An [error code] is returned otherwise.)^ 5207** 5208** ^Shared cache is disabled by default. But this might change in 5209** future releases of SQLite. Applications that care about shared 5210** cache setting should set it explicitly. 5211** 5212** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5213** and will always return SQLITE_MISUSE. On those systems, 5214** shared cache mode should be enabled per-database connection via 5215** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5216** 5217** This interface is threadsafe on processors where writing a 5218** 32-bit integer is atomic. 5219** 5220** See Also: [SQLite Shared-Cache Mode] 5221*/ 5222int sqlite3_enable_shared_cache(int); 5223 5224/* 5225** CAPI3REF: Attempt To Free Heap Memory 5226** 5227** ^The sqlite3_release_memory() interface attempts to free N bytes 5228** of heap memory by deallocating non-essential memory allocations 5229** held by the database library. Memory used to cache database 5230** pages to improve performance is an example of non-essential memory. 5231** ^sqlite3_release_memory() returns the number of bytes actually freed, 5232** which might be more or less than the amount requested. 5233** ^The sqlite3_release_memory() routine is a no-op returning zero 5234** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5235** 5236** See also: [sqlite3_db_release_memory()] 5237*/ 5238int sqlite3_release_memory(int); 5239 5240/* 5241** CAPI3REF: Free Memory Used By A Database Connection 5242** METHOD: sqlite3 5243** 5244** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5245** memory as possible from database connection D. Unlike the 5246** [sqlite3_release_memory()] interface, this interface is in effect even 5247** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5248** omitted. 5249** 5250** See also: [sqlite3_release_memory()] 5251*/ 5252int sqlite3_db_release_memory(sqlite3*); 5253 5254/* 5255** CAPI3REF: Impose A Limit On Heap Size 5256** 5257** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5258** soft limit on the amount of heap memory that may be allocated by SQLite. 5259** ^SQLite strives to keep heap memory utilization below the soft heap 5260** limit by reducing the number of pages held in the page cache 5261** as heap memory usages approaches the limit. 5262** ^The soft heap limit is "soft" because even though SQLite strives to stay 5263** below the limit, it will exceed the limit rather than generate 5264** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5265** is advisory only. 5266** 5267** ^The return value from sqlite3_soft_heap_limit64() is the size of 5268** the soft heap limit prior to the call, or negative in the case of an 5269** error. ^If the argument N is negative 5270** then no change is made to the soft heap limit. Hence, the current 5271** size of the soft heap limit can be determined by invoking 5272** sqlite3_soft_heap_limit64() with a negative argument. 5273** 5274** ^If the argument N is zero then the soft heap limit is disabled. 5275** 5276** ^(The soft heap limit is not enforced in the current implementation 5277** if one or more of following conditions are true: 5278** 5279** <ul> 5280** <li> The soft heap limit is set to zero. 5281** <li> Memory accounting is disabled using a combination of the 5282** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5283** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5284** <li> An alternative page cache implementation is specified using 5285** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5286** <li> The page cache allocates from its own memory pool supplied 5287** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5288** from the heap. 5289** </ul>)^ 5290** 5291** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 5292** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5293** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5294** the soft heap limit is enforced on every memory allocation. Without 5295** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5296** when memory is allocated by the page cache. Testing suggests that because 5297** the page cache is the predominate memory user in SQLite, most 5298** applications will achieve adequate soft heap limit enforcement without 5299** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5300** 5301** The circumstances under which SQLite will enforce the soft heap limit may 5302** changes in future releases of SQLite. 5303*/ 5304sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5305 5306/* 5307** CAPI3REF: Deprecated Soft Heap Limit Interface 5308** DEPRECATED 5309** 5310** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5311** interface. This routine is provided for historical compatibility 5312** only. All new applications should use the 5313** [sqlite3_soft_heap_limit64()] interface rather than this one. 5314*/ 5315SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5316 5317 5318/* 5319** CAPI3REF: Extract Metadata About A Column Of A Table 5320** METHOD: sqlite3 5321** 5322** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5323** information about column C of table T in database D 5324** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5325** interface returns SQLITE_OK and fills in the non-NULL pointers in 5326** the final five arguments with appropriate values if the specified 5327** column exists. ^The sqlite3_table_column_metadata() interface returns 5328** SQLITE_ERROR and if the specified column does not exist. 5329** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5330** NULL pointer, then this routine simply checks for the existance of the 5331** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5332** does not. 5333** 5334** ^The column is identified by the second, third and fourth parameters to 5335** this function. ^(The second parameter is either the name of the database 5336** (i.e. "main", "temp", or an attached database) containing the specified 5337** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5338** for the table using the same algorithm used by the database engine to 5339** resolve unqualified table references. 5340** 5341** ^The third and fourth parameters to this function are the table and column 5342** name of the desired column, respectively. 5343** 5344** ^Metadata is returned by writing to the memory locations passed as the 5th 5345** and subsequent parameters to this function. ^Any of these arguments may be 5346** NULL, in which case the corresponding element of metadata is omitted. 5347** 5348** ^(<blockquote> 5349** <table border="1"> 5350** <tr><th> Parameter <th> Output<br>Type <th> Description 5351** 5352** <tr><td> 5th <td> const char* <td> Data type 5353** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5354** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5355** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5356** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5357** </table> 5358** </blockquote>)^ 5359** 5360** ^The memory pointed to by the character pointers returned for the 5361** declaration type and collation sequence is valid until the next 5362** call to any SQLite API function. 5363** 5364** ^If the specified table is actually a view, an [error code] is returned. 5365** 5366** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5367** is not a [WITHOUT ROWID] table and an 5368** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5369** parameters are set for the explicitly declared column. ^(If there is no 5370** [INTEGER PRIMARY KEY] column, then the outputs 5371** for the [rowid] are set as follows: 5372** 5373** <pre> 5374** data type: "INTEGER" 5375** collation sequence: "BINARY" 5376** not null: 0 5377** primary key: 1 5378** auto increment: 0 5379** </pre>)^ 5380** 5381** ^This function causes all database schemas to be read from disk and 5382** parsed, if that has not already been done, and returns an error if 5383** any errors are encountered while loading the schema. 5384*/ 5385int sqlite3_table_column_metadata( 5386 sqlite3 *db, /* Connection handle */ 5387 const char *zDbName, /* Database name or NULL */ 5388 const char *zTableName, /* Table name */ 5389 const char *zColumnName, /* Column name */ 5390 char const **pzDataType, /* OUTPUT: Declared data type */ 5391 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5392 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5393 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5394 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5395); 5396 5397/* 5398** CAPI3REF: Load An Extension 5399** METHOD: sqlite3 5400** 5401** ^This interface loads an SQLite extension library from the named file. 5402** 5403** ^The sqlite3_load_extension() interface attempts to load an 5404** [SQLite extension] library contained in the file zFile. If 5405** the file cannot be loaded directly, attempts are made to load 5406** with various operating-system specific extensions added. 5407** So for example, if "samplelib" cannot be loaded, then names like 5408** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5409** be tried also. 5410** 5411** ^The entry point is zProc. 5412** ^(zProc may be 0, in which case SQLite will try to come up with an 5413** entry point name on its own. It first tries "sqlite3_extension_init". 5414** If that does not work, it constructs a name "sqlite3_X_init" where the 5415** X is consists of the lower-case equivalent of all ASCII alphabetic 5416** characters in the filename from the last "/" to the first following 5417** "." and omitting any initial "lib".)^ 5418** ^The sqlite3_load_extension() interface returns 5419** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5420** ^If an error occurs and pzErrMsg is not 0, then the 5421** [sqlite3_load_extension()] interface shall attempt to 5422** fill *pzErrMsg with error message text stored in memory 5423** obtained from [sqlite3_malloc()]. The calling function 5424** should free this memory by calling [sqlite3_free()]. 5425** 5426** ^Extension loading must be enabled using 5427** [sqlite3_enable_load_extension()] prior to calling this API, 5428** otherwise an error will be returned. 5429** 5430** See also the [load_extension() SQL function]. 5431*/ 5432int sqlite3_load_extension( 5433 sqlite3 *db, /* Load the extension into this database connection */ 5434 const char *zFile, /* Name of the shared library containing extension */ 5435 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5436 char **pzErrMsg /* Put error message here if not 0 */ 5437); 5438 5439/* 5440** CAPI3REF: Enable Or Disable Extension Loading 5441** METHOD: sqlite3 5442** 5443** ^So as not to open security holes in older applications that are 5444** unprepared to deal with [extension loading], and as a means of disabling 5445** [extension loading] while evaluating user-entered SQL, the following API 5446** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5447** 5448** ^Extension loading is off by default. 5449** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5450** to turn extension loading on and call it with onoff==0 to turn 5451** it back off again. 5452*/ 5453int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5454 5455/* 5456** CAPI3REF: Automatically Load Statically Linked Extensions 5457** 5458** ^This interface causes the xEntryPoint() function to be invoked for 5459** each new [database connection] that is created. The idea here is that 5460** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5461** that is to be automatically loaded into all new database connections. 5462** 5463** ^(Even though the function prototype shows that xEntryPoint() takes 5464** no arguments and returns void, SQLite invokes xEntryPoint() with three 5465** arguments and expects and integer result as if the signature of the 5466** entry point where as follows: 5467** 5468** <blockquote><pre> 5469** int xEntryPoint( 5470** sqlite3 *db, 5471** const char **pzErrMsg, 5472** const struct sqlite3_api_routines *pThunk 5473** ); 5474** </pre></blockquote>)^ 5475** 5476** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5477** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5478** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5479** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5480** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5481** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5482** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5483** 5484** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5485** on the list of automatic extensions is a harmless no-op. ^No entry point 5486** will be called more than once for each database connection that is opened. 5487** 5488** See also: [sqlite3_reset_auto_extension()] 5489** and [sqlite3_cancel_auto_extension()] 5490*/ 5491int sqlite3_auto_extension(void (*xEntryPoint)(void)); 5492 5493/* 5494** CAPI3REF: Cancel Automatic Extension Loading 5495** 5496** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5497** initialization routine X that was registered using a prior call to 5498** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5499** routine returns 1 if initialization routine X was successfully 5500** unregistered and it returns 0 if X was not on the list of initialization 5501** routines. 5502*/ 5503int sqlite3_cancel_auto_extension(void (*xEntryPoint)(void)); 5504 5505/* 5506** CAPI3REF: Reset Automatic Extension Loading 5507** 5508** ^This interface disables all automatic extensions previously 5509** registered using [sqlite3_auto_extension()]. 5510*/ 5511void sqlite3_reset_auto_extension(void); 5512 5513/* 5514** The interface to the virtual-table mechanism is currently considered 5515** to be experimental. The interface might change in incompatible ways. 5516** If this is a problem for you, do not use the interface at this time. 5517** 5518** When the virtual-table mechanism stabilizes, we will declare the 5519** interface fixed, support it indefinitely, and remove this comment. 5520*/ 5521 5522/* 5523** Structures used by the virtual table interface 5524*/ 5525typedef struct sqlite3_vtab sqlite3_vtab; 5526typedef struct sqlite3_index_info sqlite3_index_info; 5527typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5528typedef struct sqlite3_module sqlite3_module; 5529 5530/* 5531** CAPI3REF: Virtual Table Object 5532** KEYWORDS: sqlite3_module {virtual table module} 5533** 5534** This structure, sometimes called a "virtual table module", 5535** defines the implementation of a [virtual tables]. 5536** This structure consists mostly of methods for the module. 5537** 5538** ^A virtual table module is created by filling in a persistent 5539** instance of this structure and passing a pointer to that instance 5540** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5541** ^The registration remains valid until it is replaced by a different 5542** module or until the [database connection] closes. The content 5543** of this structure must not change while it is registered with 5544** any database connection. 5545*/ 5546struct sqlite3_module { 5547 int iVersion; 5548 int (*xCreate)(sqlite3*, void *pAux, 5549 int argc, const char *const*argv, 5550 sqlite3_vtab **ppVTab, char**); 5551 int (*xConnect)(sqlite3*, void *pAux, 5552 int argc, const char *const*argv, 5553 sqlite3_vtab **ppVTab, char**); 5554 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5555 int (*xDisconnect)(sqlite3_vtab *pVTab); 5556 int (*xDestroy)(sqlite3_vtab *pVTab); 5557 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5558 int (*xClose)(sqlite3_vtab_cursor*); 5559 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5560 int argc, sqlite3_value **argv); 5561 int (*xNext)(sqlite3_vtab_cursor*); 5562 int (*xEof)(sqlite3_vtab_cursor*); 5563 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5564 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5565 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5566 int (*xBegin)(sqlite3_vtab *pVTab); 5567 int (*xSync)(sqlite3_vtab *pVTab); 5568 int (*xCommit)(sqlite3_vtab *pVTab); 5569 int (*xRollback)(sqlite3_vtab *pVTab); 5570 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5571 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5572 void **ppArg); 5573 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5574 /* The methods above are in version 1 of the sqlite_module object. Those 5575 ** below are for version 2 and greater. */ 5576 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5577 int (*xRelease)(sqlite3_vtab *pVTab, int); 5578 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5579}; 5580 5581/* 5582** CAPI3REF: Virtual Table Indexing Information 5583** KEYWORDS: sqlite3_index_info 5584** 5585** The sqlite3_index_info structure and its substructures is used as part 5586** of the [virtual table] interface to 5587** pass information into and receive the reply from the [xBestIndex] 5588** method of a [virtual table module]. The fields under **Inputs** are the 5589** inputs to xBestIndex and are read-only. xBestIndex inserts its 5590** results into the **Outputs** fields. 5591** 5592** ^(The aConstraint[] array records WHERE clause constraints of the form: 5593** 5594** <blockquote>column OP expr</blockquote> 5595** 5596** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5597** stored in aConstraint[].op using one of the 5598** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5599** ^(The index of the column is stored in 5600** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5601** expr on the right-hand side can be evaluated (and thus the constraint 5602** is usable) and false if it cannot.)^ 5603** 5604** ^The optimizer automatically inverts terms of the form "expr OP column" 5605** and makes other simplifications to the WHERE clause in an attempt to 5606** get as many WHERE clause terms into the form shown above as possible. 5607** ^The aConstraint[] array only reports WHERE clause terms that are 5608** relevant to the particular virtual table being queried. 5609** 5610** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5611** ^Each term of aOrderBy records a column of the ORDER BY clause. 5612** 5613** The [xBestIndex] method must fill aConstraintUsage[] with information 5614** about what parameters to pass to xFilter. ^If argvIndex>0 then 5615** the right-hand side of the corresponding aConstraint[] is evaluated 5616** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5617** is true, then the constraint is assumed to be fully handled by the 5618** virtual table and is not checked again by SQLite.)^ 5619** 5620** ^The idxNum and idxPtr values are recorded and passed into the 5621** [xFilter] method. 5622** ^[sqlite3_free()] is used to free idxPtr if and only if 5623** needToFreeIdxPtr is true. 5624** 5625** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5626** the correct order to satisfy the ORDER BY clause so that no separate 5627** sorting step is required. 5628** 5629** ^The estimatedCost value is an estimate of the cost of a particular 5630** strategy. A cost of N indicates that the cost of the strategy is similar 5631** to a linear scan of an SQLite table with N rows. A cost of log(N) 5632** indicates that the expense of the operation is similar to that of a 5633** binary search on a unique indexed field of an SQLite table with N rows. 5634** 5635** ^The estimatedRows value is an estimate of the number of rows that 5636** will be returned by the strategy. 5637** 5638** The xBestIndex method may optionally populate the idxFlags field with a 5639** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 5640** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 5641** assumes that the strategy may visit at most one row. 5642** 5643** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 5644** SQLite also assumes that if a call to the xUpdate() method is made as 5645** part of the same statement to delete or update a virtual table row and the 5646** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 5647** any database changes. In other words, if the xUpdate() returns 5648** SQLITE_CONSTRAINT, the database contents must be exactly as they were 5649** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 5650** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 5651** the xUpdate method are automatically rolled back by SQLite. 5652** 5653** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 5654** structure for SQLite version 3.8.2. If a virtual table extension is 5655** used with an SQLite version earlier than 3.8.2, the results of attempting 5656** to read or write the estimatedRows field are undefined (but are likely 5657** to included crashing the application). The estimatedRows field should 5658** therefore only be used if [sqlite3_libversion_number()] returns a 5659** value greater than or equal to 3008002. Similarly, the idxFlags field 5660** was added for version 3.9.0. It may therefore only be used if 5661** sqlite3_libversion_number() returns a value greater than or equal to 5662** 3009000. 5663*/ 5664struct sqlite3_index_info { 5665 /* Inputs */ 5666 int nConstraint; /* Number of entries in aConstraint */ 5667 struct sqlite3_index_constraint { 5668 int iColumn; /* Column on left-hand side of constraint */ 5669 unsigned char op; /* Constraint operator */ 5670 unsigned char usable; /* True if this constraint is usable */ 5671 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5672 } *aConstraint; /* Table of WHERE clause constraints */ 5673 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5674 struct sqlite3_index_orderby { 5675 int iColumn; /* Column number */ 5676 unsigned char desc; /* True for DESC. False for ASC. */ 5677 } *aOrderBy; /* The ORDER BY clause */ 5678 /* Outputs */ 5679 struct sqlite3_index_constraint_usage { 5680 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5681 unsigned char omit; /* Do not code a test for this constraint */ 5682 } *aConstraintUsage; 5683 int idxNum; /* Number used to identify the index */ 5684 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5685 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5686 int orderByConsumed; /* True if output is already ordered */ 5687 double estimatedCost; /* Estimated cost of using this index */ 5688 /* Fields below are only available in SQLite 3.8.2 and later */ 5689 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 5690 /* Fields below are only available in SQLite 3.9.0 and later */ 5691 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 5692}; 5693 5694/* 5695** CAPI3REF: Virtual Table Scan Flags 5696*/ 5697#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 5698 5699/* 5700** CAPI3REF: Virtual Table Constraint Operator Codes 5701** 5702** These macros defined the allowed values for the 5703** [sqlite3_index_info].aConstraint[].op field. Each value represents 5704** an operator that is part of a constraint term in the wHERE clause of 5705** a query that uses a [virtual table]. 5706*/ 5707#define SQLITE_INDEX_CONSTRAINT_EQ 2 5708#define SQLITE_INDEX_CONSTRAINT_GT 4 5709#define SQLITE_INDEX_CONSTRAINT_LE 8 5710#define SQLITE_INDEX_CONSTRAINT_LT 16 5711#define SQLITE_INDEX_CONSTRAINT_GE 32 5712#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5713 5714/* 5715** CAPI3REF: Register A Virtual Table Implementation 5716** METHOD: sqlite3 5717** 5718** ^These routines are used to register a new [virtual table module] name. 5719** ^Module names must be registered before 5720** creating a new [virtual table] using the module and before using a 5721** preexisting [virtual table] for the module. 5722** 5723** ^The module name is registered on the [database connection] specified 5724** by the first parameter. ^The name of the module is given by the 5725** second parameter. ^The third parameter is a pointer to 5726** the implementation of the [virtual table module]. ^The fourth 5727** parameter is an arbitrary client data pointer that is passed through 5728** into the [xCreate] and [xConnect] methods of the virtual table module 5729** when a new virtual table is be being created or reinitialized. 5730** 5731** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5732** is a pointer to a destructor for the pClientData. ^SQLite will 5733** invoke the destructor function (if it is not NULL) when SQLite 5734** no longer needs the pClientData pointer. ^The destructor will also 5735** be invoked if the call to sqlite3_create_module_v2() fails. 5736** ^The sqlite3_create_module() 5737** interface is equivalent to sqlite3_create_module_v2() with a NULL 5738** destructor. 5739*/ 5740int sqlite3_create_module( 5741 sqlite3 *db, /* SQLite connection to register module with */ 5742 const char *zName, /* Name of the module */ 5743 const sqlite3_module *p, /* Methods for the module */ 5744 void *pClientData /* Client data for xCreate/xConnect */ 5745); 5746int sqlite3_create_module_v2( 5747 sqlite3 *db, /* SQLite connection to register module with */ 5748 const char *zName, /* Name of the module */ 5749 const sqlite3_module *p, /* Methods for the module */ 5750 void *pClientData, /* Client data for xCreate/xConnect */ 5751 void(*xDestroy)(void*) /* Module destructor function */ 5752); 5753 5754/* 5755** CAPI3REF: Virtual Table Instance Object 5756** KEYWORDS: sqlite3_vtab 5757** 5758** Every [virtual table module] implementation uses a subclass 5759** of this object to describe a particular instance 5760** of the [virtual table]. Each subclass will 5761** be tailored to the specific needs of the module implementation. 5762** The purpose of this superclass is to define certain fields that are 5763** common to all module implementations. 5764** 5765** ^Virtual tables methods can set an error message by assigning a 5766** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5767** take care that any prior string is freed by a call to [sqlite3_free()] 5768** prior to assigning a new string to zErrMsg. ^After the error message 5769** is delivered up to the client application, the string will be automatically 5770** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5771*/ 5772struct sqlite3_vtab { 5773 const sqlite3_module *pModule; /* The module for this virtual table */ 5774 int nRef; /* Number of open cursors */ 5775 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5776 /* Virtual table implementations will typically add additional fields */ 5777}; 5778 5779/* 5780** CAPI3REF: Virtual Table Cursor Object 5781** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5782** 5783** Every [virtual table module] implementation uses a subclass of the 5784** following structure to describe cursors that point into the 5785** [virtual table] and are used 5786** to loop through the virtual table. Cursors are created using the 5787** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5788** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5789** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5790** of the module. Each module implementation will define 5791** the content of a cursor structure to suit its own needs. 5792** 5793** This superclass exists in order to define fields of the cursor that 5794** are common to all implementations. 5795*/ 5796struct sqlite3_vtab_cursor { 5797 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5798 /* Virtual table implementations will typically add additional fields */ 5799}; 5800 5801/* 5802** CAPI3REF: Declare The Schema Of A Virtual Table 5803** 5804** ^The [xCreate] and [xConnect] methods of a 5805** [virtual table module] call this interface 5806** to declare the format (the names and datatypes of the columns) of 5807** the virtual tables they implement. 5808*/ 5809int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5810 5811/* 5812** CAPI3REF: Overload A Function For A Virtual Table 5813** METHOD: sqlite3 5814** 5815** ^(Virtual tables can provide alternative implementations of functions 5816** using the [xFindFunction] method of the [virtual table module]. 5817** But global versions of those functions 5818** must exist in order to be overloaded.)^ 5819** 5820** ^(This API makes sure a global version of a function with a particular 5821** name and number of parameters exists. If no such function exists 5822** before this API is called, a new function is created.)^ ^The implementation 5823** of the new function always causes an exception to be thrown. So 5824** the new function is not good for anything by itself. Its only 5825** purpose is to be a placeholder function that can be overloaded 5826** by a [virtual table]. 5827*/ 5828int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5829 5830/* 5831** The interface to the virtual-table mechanism defined above (back up 5832** to a comment remarkably similar to this one) is currently considered 5833** to be experimental. The interface might change in incompatible ways. 5834** If this is a problem for you, do not use the interface at this time. 5835** 5836** When the virtual-table mechanism stabilizes, we will declare the 5837** interface fixed, support it indefinitely, and remove this comment. 5838*/ 5839 5840/* 5841** CAPI3REF: A Handle To An Open BLOB 5842** KEYWORDS: {BLOB handle} {BLOB handles} 5843** 5844** An instance of this object represents an open BLOB on which 5845** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5846** ^Objects of this type are created by [sqlite3_blob_open()] 5847** and destroyed by [sqlite3_blob_close()]. 5848** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5849** can be used to read or write small subsections of the BLOB. 5850** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5851*/ 5852typedef struct sqlite3_blob sqlite3_blob; 5853 5854/* 5855** CAPI3REF: Open A BLOB For Incremental I/O 5856** METHOD: sqlite3 5857** CONSTRUCTOR: sqlite3_blob 5858** 5859** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5860** in row iRow, column zColumn, table zTable in database zDb; 5861** in other words, the same BLOB that would be selected by: 5862** 5863** <pre> 5864** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5865** </pre>)^ 5866** 5867** ^(Parameter zDb is not the filename that contains the database, but 5868** rather the symbolic name of the database. For attached databases, this is 5869** the name that appears after the AS keyword in the [ATTACH] statement. 5870** For the main database file, the database name is "main". For TEMP 5871** tables, the database name is "temp".)^ 5872** 5873** ^If the flags parameter is non-zero, then the BLOB is opened for read 5874** and write access. ^If the flags parameter is zero, the BLOB is opened for 5875** read-only access. 5876** 5877** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 5878** in *ppBlob. Otherwise an [error code] is returned and, unless the error 5879** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 5880** the API is not misused, it is always safe to call [sqlite3_blob_close()] 5881** on *ppBlob after this function it returns. 5882** 5883** This function fails with SQLITE_ERROR if any of the following are true: 5884** <ul> 5885** <li> ^(Database zDb does not exist)^, 5886** <li> ^(Table zTable does not exist within database zDb)^, 5887** <li> ^(Table zTable is a WITHOUT ROWID table)^, 5888** <li> ^(Column zColumn does not exist)^, 5889** <li> ^(Row iRow is not present in the table)^, 5890** <li> ^(The specified column of row iRow contains a value that is not 5891** a TEXT or BLOB value)^, 5892** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 5893** constraint and the blob is being opened for read/write access)^, 5894** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 5895** column zColumn is part of a [child key] definition and the blob is 5896** being opened for read/write access)^. 5897** </ul> 5898** 5899** ^Unless it returns SQLITE_MISUSE, this function sets the 5900** [database connection] error code and message accessible via 5901** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 5902** 5903** 5904** ^(If the row that a BLOB handle points to is modified by an 5905** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5906** then the BLOB handle is marked as "expired". 5907** This is true if any column of the row is changed, even a column 5908** other than the one the BLOB handle is open on.)^ 5909** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5910** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5911** ^(Changes written into a BLOB prior to the BLOB expiring are not 5912** rolled back by the expiration of the BLOB. Such changes will eventually 5913** commit if the transaction continues to completion.)^ 5914** 5915** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5916** the opened blob. ^The size of a blob may not be changed by this 5917** interface. Use the [UPDATE] SQL command to change the size of a 5918** blob. 5919** 5920** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5921** and the built-in [zeroblob] SQL function may be used to create a 5922** zero-filled blob to read or write using the incremental-blob interface. 5923** 5924** To avoid a resource leak, every open [BLOB handle] should eventually 5925** be released by a call to [sqlite3_blob_close()]. 5926*/ 5927int sqlite3_blob_open( 5928 sqlite3*, 5929 const char *zDb, 5930 const char *zTable, 5931 const char *zColumn, 5932 sqlite3_int64 iRow, 5933 int flags, 5934 sqlite3_blob **ppBlob 5935); 5936 5937/* 5938** CAPI3REF: Move a BLOB Handle to a New Row 5939** METHOD: sqlite3_blob 5940** 5941** ^This function is used to move an existing blob handle so that it points 5942** to a different row of the same database table. ^The new row is identified 5943** by the rowid value passed as the second argument. Only the row can be 5944** changed. ^The database, table and column on which the blob handle is open 5945** remain the same. Moving an existing blob handle to a new row can be 5946** faster than closing the existing handle and opening a new one. 5947** 5948** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5949** it must exist and there must be either a blob or text value stored in 5950** the nominated column.)^ ^If the new row is not present in the table, or if 5951** it does not contain a blob or text value, or if another error occurs, an 5952** SQLite error code is returned and the blob handle is considered aborted. 5953** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5954** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5955** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5956** always returns zero. 5957** 5958** ^This function sets the database handle error code and message. 5959*/ 5960int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5961 5962/* 5963** CAPI3REF: Close A BLOB Handle 5964** DESTRUCTOR: sqlite3_blob 5965** 5966** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 5967** unconditionally. Even if this routine returns an error code, the 5968** handle is still closed.)^ 5969** 5970** ^If the blob handle being closed was opened for read-write access, and if 5971** the database is in auto-commit mode and there are no other open read-write 5972** blob handles or active write statements, the current transaction is 5973** committed. ^If an error occurs while committing the transaction, an error 5974** code is returned and the transaction rolled back. 5975** 5976** Calling this function with an argument that is not a NULL pointer or an 5977** open blob handle results in undefined behaviour. ^Calling this routine 5978** with a null pointer (such as would be returned by a failed call to 5979** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 5980** is passed a valid open blob handle, the values returned by the 5981** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 5982*/ 5983int sqlite3_blob_close(sqlite3_blob *); 5984 5985/* 5986** CAPI3REF: Return The Size Of An Open BLOB 5987** METHOD: sqlite3_blob 5988** 5989** ^Returns the size in bytes of the BLOB accessible via the 5990** successfully opened [BLOB handle] in its only argument. ^The 5991** incremental blob I/O routines can only read or overwriting existing 5992** blob content; they cannot change the size of a blob. 5993** 5994** This routine only works on a [BLOB handle] which has been created 5995** by a prior successful call to [sqlite3_blob_open()] and which has not 5996** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5997** to this routine results in undefined and probably undesirable behavior. 5998*/ 5999int sqlite3_blob_bytes(sqlite3_blob *); 6000 6001/* 6002** CAPI3REF: Read Data From A BLOB Incrementally 6003** METHOD: sqlite3_blob 6004** 6005** ^(This function is used to read data from an open [BLOB handle] into a 6006** caller-supplied buffer. N bytes of data are copied into buffer Z 6007** from the open BLOB, starting at offset iOffset.)^ 6008** 6009** ^If offset iOffset is less than N bytes from the end of the BLOB, 6010** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6011** less than zero, [SQLITE_ERROR] is returned and no data is read. 6012** ^The size of the blob (and hence the maximum value of N+iOffset) 6013** can be determined using the [sqlite3_blob_bytes()] interface. 6014** 6015** ^An attempt to read from an expired [BLOB handle] fails with an 6016** error code of [SQLITE_ABORT]. 6017** 6018** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6019** Otherwise, an [error code] or an [extended error code] is returned.)^ 6020** 6021** This routine only works on a [BLOB handle] which has been created 6022** by a prior successful call to [sqlite3_blob_open()] and which has not 6023** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6024** to this routine results in undefined and probably undesirable behavior. 6025** 6026** See also: [sqlite3_blob_write()]. 6027*/ 6028int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6029 6030/* 6031** CAPI3REF: Write Data Into A BLOB Incrementally 6032** METHOD: sqlite3_blob 6033** 6034** ^(This function is used to write data into an open [BLOB handle] from a 6035** caller-supplied buffer. N bytes of data are copied from the buffer Z 6036** into the open BLOB, starting at offset iOffset.)^ 6037** 6038** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6039** Otherwise, an [error code] or an [extended error code] is returned.)^ 6040** ^Unless SQLITE_MISUSE is returned, this function sets the 6041** [database connection] error code and message accessible via 6042** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6043** 6044** ^If the [BLOB handle] passed as the first argument was not opened for 6045** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6046** this function returns [SQLITE_READONLY]. 6047** 6048** This function may only modify the contents of the BLOB; it is 6049** not possible to increase the size of a BLOB using this API. 6050** ^If offset iOffset is less than N bytes from the end of the BLOB, 6051** [SQLITE_ERROR] is returned and no data is written. The size of the 6052** BLOB (and hence the maximum value of N+iOffset) can be determined 6053** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6054** than zero [SQLITE_ERROR] is returned and no data is written. 6055** 6056** ^An attempt to write to an expired [BLOB handle] fails with an 6057** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6058** before the [BLOB handle] expired are not rolled back by the 6059** expiration of the handle, though of course those changes might 6060** have been overwritten by the statement that expired the BLOB handle 6061** or by other independent statements. 6062** 6063** This routine only works on a [BLOB handle] which has been created 6064** by a prior successful call to [sqlite3_blob_open()] and which has not 6065** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6066** to this routine results in undefined and probably undesirable behavior. 6067** 6068** See also: [sqlite3_blob_read()]. 6069*/ 6070int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6071 6072/* 6073** CAPI3REF: Virtual File System Objects 6074** 6075** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6076** that SQLite uses to interact 6077** with the underlying operating system. Most SQLite builds come with a 6078** single default VFS that is appropriate for the host computer. 6079** New VFSes can be registered and existing VFSes can be unregistered. 6080** The following interfaces are provided. 6081** 6082** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6083** ^Names are case sensitive. 6084** ^Names are zero-terminated UTF-8 strings. 6085** ^If there is no match, a NULL pointer is returned. 6086** ^If zVfsName is NULL then the default VFS is returned. 6087** 6088** ^New VFSes are registered with sqlite3_vfs_register(). 6089** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6090** ^The same VFS can be registered multiple times without injury. 6091** ^To make an existing VFS into the default VFS, register it again 6092** with the makeDflt flag set. If two different VFSes with the 6093** same name are registered, the behavior is undefined. If a 6094** VFS is registered with a name that is NULL or an empty string, 6095** then the behavior is undefined. 6096** 6097** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6098** ^(If the default VFS is unregistered, another VFS is chosen as 6099** the default. The choice for the new VFS is arbitrary.)^ 6100*/ 6101sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6102int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6103int sqlite3_vfs_unregister(sqlite3_vfs*); 6104 6105/* 6106** CAPI3REF: Mutexes 6107** 6108** The SQLite core uses these routines for thread 6109** synchronization. Though they are intended for internal 6110** use by SQLite, code that links against SQLite is 6111** permitted to use any of these routines. 6112** 6113** The SQLite source code contains multiple implementations 6114** of these mutex routines. An appropriate implementation 6115** is selected automatically at compile-time. The following 6116** implementations are available in the SQLite core: 6117** 6118** <ul> 6119** <li> SQLITE_MUTEX_PTHREADS 6120** <li> SQLITE_MUTEX_W32 6121** <li> SQLITE_MUTEX_NOOP 6122** </ul> 6123** 6124** The SQLITE_MUTEX_NOOP implementation is a set of routines 6125** that does no real locking and is appropriate for use in 6126** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6127** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6128** and Windows. 6129** 6130** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6131** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6132** implementation is included with the library. In this case the 6133** application must supply a custom mutex implementation using the 6134** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6135** before calling sqlite3_initialize() or any other public sqlite3_ 6136** function that calls sqlite3_initialize(). 6137** 6138** ^The sqlite3_mutex_alloc() routine allocates a new 6139** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6140** routine returns NULL if it is unable to allocate the requested 6141** mutex. The argument to sqlite3_mutex_alloc() must one of these 6142** integer constants: 6143** 6144** <ul> 6145** <li> SQLITE_MUTEX_FAST 6146** <li> SQLITE_MUTEX_RECURSIVE 6147** <li> SQLITE_MUTEX_STATIC_MASTER 6148** <li> SQLITE_MUTEX_STATIC_MEM 6149** <li> SQLITE_MUTEX_STATIC_OPEN 6150** <li> SQLITE_MUTEX_STATIC_PRNG 6151** <li> SQLITE_MUTEX_STATIC_LRU 6152** <li> SQLITE_MUTEX_STATIC_PMEM 6153** <li> SQLITE_MUTEX_STATIC_APP1 6154** <li> SQLITE_MUTEX_STATIC_APP2 6155** <li> SQLITE_MUTEX_STATIC_APP3 6156** <li> SQLITE_MUTEX_STATIC_VFS1 6157** <li> SQLITE_MUTEX_STATIC_VFS2 6158** <li> SQLITE_MUTEX_STATIC_VFS3 6159** </ul> 6160** 6161** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6162** cause sqlite3_mutex_alloc() to create 6163** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6164** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6165** The mutex implementation does not need to make a distinction 6166** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6167** not want to. SQLite will only request a recursive mutex in 6168** cases where it really needs one. If a faster non-recursive mutex 6169** implementation is available on the host platform, the mutex subsystem 6170** might return such a mutex in response to SQLITE_MUTEX_FAST. 6171** 6172** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6173** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6174** a pointer to a static preexisting mutex. ^Nine static mutexes are 6175** used by the current version of SQLite. Future versions of SQLite 6176** may add additional static mutexes. Static mutexes are for internal 6177** use by SQLite only. Applications that use SQLite mutexes should 6178** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6179** SQLITE_MUTEX_RECURSIVE. 6180** 6181** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6182** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6183** returns a different mutex on every call. ^For the static 6184** mutex types, the same mutex is returned on every call that has 6185** the same type number. 6186** 6187** ^The sqlite3_mutex_free() routine deallocates a previously 6188** allocated dynamic mutex. Attempting to deallocate a static 6189** mutex results in undefined behavior. 6190** 6191** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6192** to enter a mutex. ^If another thread is already within the mutex, 6193** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6194** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6195** upon successful entry. ^(Mutexes created using 6196** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6197** In such cases, the 6198** mutex must be exited an equal number of times before another thread 6199** can enter.)^ If the same thread tries to enter any mutex other 6200** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6201** 6202** ^(Some systems (for example, Windows 95) do not support the operation 6203** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6204** will always return SQLITE_BUSY. The SQLite core only ever uses 6205** sqlite3_mutex_try() as an optimization so this is acceptable 6206** behavior.)^ 6207** 6208** ^The sqlite3_mutex_leave() routine exits a mutex that was 6209** previously entered by the same thread. The behavior 6210** is undefined if the mutex is not currently entered by the 6211** calling thread or is not currently allocated. 6212** 6213** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6214** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6215** behave as no-ops. 6216** 6217** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6218*/ 6219sqlite3_mutex *sqlite3_mutex_alloc(int); 6220void sqlite3_mutex_free(sqlite3_mutex*); 6221void sqlite3_mutex_enter(sqlite3_mutex*); 6222int sqlite3_mutex_try(sqlite3_mutex*); 6223void sqlite3_mutex_leave(sqlite3_mutex*); 6224 6225/* 6226** CAPI3REF: Mutex Methods Object 6227** 6228** An instance of this structure defines the low-level routines 6229** used to allocate and use mutexes. 6230** 6231** Usually, the default mutex implementations provided by SQLite are 6232** sufficient, however the application has the option of substituting a custom 6233** implementation for specialized deployments or systems for which SQLite 6234** does not provide a suitable implementation. In this case, the application 6235** creates and populates an instance of this structure to pass 6236** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6237** Additionally, an instance of this structure can be used as an 6238** output variable when querying the system for the current mutex 6239** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6240** 6241** ^The xMutexInit method defined by this structure is invoked as 6242** part of system initialization by the sqlite3_initialize() function. 6243** ^The xMutexInit routine is called by SQLite exactly once for each 6244** effective call to [sqlite3_initialize()]. 6245** 6246** ^The xMutexEnd method defined by this structure is invoked as 6247** part of system shutdown by the sqlite3_shutdown() function. The 6248** implementation of this method is expected to release all outstanding 6249** resources obtained by the mutex methods implementation, especially 6250** those obtained by the xMutexInit method. ^The xMutexEnd() 6251** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6252** 6253** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6254** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6255** xMutexNotheld) implement the following interfaces (respectively): 6256** 6257** <ul> 6258** <li> [sqlite3_mutex_alloc()] </li> 6259** <li> [sqlite3_mutex_free()] </li> 6260** <li> [sqlite3_mutex_enter()] </li> 6261** <li> [sqlite3_mutex_try()] </li> 6262** <li> [sqlite3_mutex_leave()] </li> 6263** <li> [sqlite3_mutex_held()] </li> 6264** <li> [sqlite3_mutex_notheld()] </li> 6265** </ul>)^ 6266** 6267** The only difference is that the public sqlite3_XXX functions enumerated 6268** above silently ignore any invocations that pass a NULL pointer instead 6269** of a valid mutex handle. The implementations of the methods defined 6270** by this structure are not required to handle this case, the results 6271** of passing a NULL pointer instead of a valid mutex handle are undefined 6272** (i.e. it is acceptable to provide an implementation that segfaults if 6273** it is passed a NULL pointer). 6274** 6275** The xMutexInit() method must be threadsafe. It must be harmless to 6276** invoke xMutexInit() multiple times within the same process and without 6277** intervening calls to xMutexEnd(). Second and subsequent calls to 6278** xMutexInit() must be no-ops. 6279** 6280** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6281** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6282** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6283** memory allocation for a fast or recursive mutex. 6284** 6285** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6286** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6287** If xMutexInit fails in any way, it is expected to clean up after itself 6288** prior to returning. 6289*/ 6290typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6291struct sqlite3_mutex_methods { 6292 int (*xMutexInit)(void); 6293 int (*xMutexEnd)(void); 6294 sqlite3_mutex *(*xMutexAlloc)(int); 6295 void (*xMutexFree)(sqlite3_mutex *); 6296 void (*xMutexEnter)(sqlite3_mutex *); 6297 int (*xMutexTry)(sqlite3_mutex *); 6298 void (*xMutexLeave)(sqlite3_mutex *); 6299 int (*xMutexHeld)(sqlite3_mutex *); 6300 int (*xMutexNotheld)(sqlite3_mutex *); 6301}; 6302 6303/* 6304** CAPI3REF: Mutex Verification Routines 6305** 6306** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6307** are intended for use inside assert() statements. The SQLite core 6308** never uses these routines except inside an assert() and applications 6309** are advised to follow the lead of the core. The SQLite core only 6310** provides implementations for these routines when it is compiled 6311** with the SQLITE_DEBUG flag. External mutex implementations 6312** are only required to provide these routines if SQLITE_DEBUG is 6313** defined and if NDEBUG is not defined. 6314** 6315** These routines should return true if the mutex in their argument 6316** is held or not held, respectively, by the calling thread. 6317** 6318** The implementation is not required to provide versions of these 6319** routines that actually work. If the implementation does not provide working 6320** versions of these routines, it should at least provide stubs that always 6321** return true so that one does not get spurious assertion failures. 6322** 6323** If the argument to sqlite3_mutex_held() is a NULL pointer then 6324** the routine should return 1. This seems counter-intuitive since 6325** clearly the mutex cannot be held if it does not exist. But 6326** the reason the mutex does not exist is because the build is not 6327** using mutexes. And we do not want the assert() containing the 6328** call to sqlite3_mutex_held() to fail, so a non-zero return is 6329** the appropriate thing to do. The sqlite3_mutex_notheld() 6330** interface should also return 1 when given a NULL pointer. 6331*/ 6332#ifndef NDEBUG 6333int sqlite3_mutex_held(sqlite3_mutex*); 6334int sqlite3_mutex_notheld(sqlite3_mutex*); 6335#endif 6336 6337/* 6338** CAPI3REF: Mutex Types 6339** 6340** The [sqlite3_mutex_alloc()] interface takes a single argument 6341** which is one of these integer constants. 6342** 6343** The set of static mutexes may change from one SQLite release to the 6344** next. Applications that override the built-in mutex logic must be 6345** prepared to accommodate additional static mutexes. 6346*/ 6347#define SQLITE_MUTEX_FAST 0 6348#define SQLITE_MUTEX_RECURSIVE 1 6349#define SQLITE_MUTEX_STATIC_MASTER 2 6350#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6351#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6352#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6353#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 6354#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6355#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6356#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6357#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6358#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6359#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6360#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6361#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6362#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6363 6364/* 6365** CAPI3REF: Retrieve the mutex for a database connection 6366** METHOD: sqlite3 6367** 6368** ^This interface returns a pointer the [sqlite3_mutex] object that 6369** serializes access to the [database connection] given in the argument 6370** when the [threading mode] is Serialized. 6371** ^If the [threading mode] is Single-thread or Multi-thread then this 6372** routine returns a NULL pointer. 6373*/ 6374sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6375 6376/* 6377** CAPI3REF: Low-Level Control Of Database Files 6378** METHOD: sqlite3 6379** 6380** ^The [sqlite3_file_control()] interface makes a direct call to the 6381** xFileControl method for the [sqlite3_io_methods] object associated 6382** with a particular database identified by the second argument. ^The 6383** name of the database is "main" for the main database or "temp" for the 6384** TEMP database, or the name that appears after the AS keyword for 6385** databases that are added using the [ATTACH] SQL command. 6386** ^A NULL pointer can be used in place of "main" to refer to the 6387** main database file. 6388** ^The third and fourth parameters to this routine 6389** are passed directly through to the second and third parameters of 6390** the xFileControl method. ^The return value of the xFileControl 6391** method becomes the return value of this routine. 6392** 6393** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6394** a pointer to the underlying [sqlite3_file] object to be written into 6395** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6396** case is a short-circuit path which does not actually invoke the 6397** underlying sqlite3_io_methods.xFileControl method. 6398** 6399** ^If the second parameter (zDbName) does not match the name of any 6400** open database file, then SQLITE_ERROR is returned. ^This error 6401** code is not remembered and will not be recalled by [sqlite3_errcode()] 6402** or [sqlite3_errmsg()]. The underlying xFileControl method might 6403** also return SQLITE_ERROR. There is no way to distinguish between 6404** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6405** xFileControl method. 6406** 6407** See also: [SQLITE_FCNTL_LOCKSTATE] 6408*/ 6409int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6410 6411/* 6412** CAPI3REF: Testing Interface 6413** 6414** ^The sqlite3_test_control() interface is used to read out internal 6415** state of SQLite and to inject faults into SQLite for testing 6416** purposes. ^The first parameter is an operation code that determines 6417** the number, meaning, and operation of all subsequent parameters. 6418** 6419** This interface is not for use by applications. It exists solely 6420** for verifying the correct operation of the SQLite library. Depending 6421** on how the SQLite library is compiled, this interface might not exist. 6422** 6423** The details of the operation codes, their meanings, the parameters 6424** they take, and what they do are all subject to change without notice. 6425** Unlike most of the SQLite API, this function is not guaranteed to 6426** operate consistently from one release to the next. 6427*/ 6428int sqlite3_test_control(int op, ...); 6429 6430/* 6431** CAPI3REF: Testing Interface Operation Codes 6432** 6433** These constants are the valid operation code parameters used 6434** as the first argument to [sqlite3_test_control()]. 6435** 6436** These parameters and their meanings are subject to change 6437** without notice. These values are for testing purposes only. 6438** Applications should not use any of these parameters or the 6439** [sqlite3_test_control()] interface. 6440*/ 6441#define SQLITE_TESTCTRL_FIRST 5 6442#define SQLITE_TESTCTRL_PRNG_SAVE 5 6443#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6444#define SQLITE_TESTCTRL_PRNG_RESET 7 6445#define SQLITE_TESTCTRL_BITVEC_TEST 8 6446#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6447#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6448#define SQLITE_TESTCTRL_PENDING_BYTE 11 6449#define SQLITE_TESTCTRL_ASSERT 12 6450#define SQLITE_TESTCTRL_ALWAYS 13 6451#define SQLITE_TESTCTRL_RESERVE 14 6452#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6453#define SQLITE_TESTCTRL_ISKEYWORD 16 6454#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6455#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6456#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6457#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6458#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6459#define SQLITE_TESTCTRL_BYTEORDER 22 6460#define SQLITE_TESTCTRL_ISINIT 23 6461#define SQLITE_TESTCTRL_SORTER_MMAP 24 6462#define SQLITE_TESTCTRL_IMPOSTER 25 6463#define SQLITE_TESTCTRL_LAST 25 6464 6465/* 6466** CAPI3REF: SQLite Runtime Status 6467** 6468** ^These interfaces are used to retrieve runtime status information 6469** about the performance of SQLite, and optionally to reset various 6470** highwater marks. ^The first argument is an integer code for 6471** the specific parameter to measure. ^(Recognized integer codes 6472** are of the form [status parameters | SQLITE_STATUS_...].)^ 6473** ^The current value of the parameter is returned into *pCurrent. 6474** ^The highest recorded value is returned in *pHighwater. ^If the 6475** resetFlag is true, then the highest record value is reset after 6476** *pHighwater is written. ^(Some parameters do not record the highest 6477** value. For those parameters 6478** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6479** ^(Other parameters record only the highwater mark and not the current 6480** value. For these latter parameters nothing is written into *pCurrent.)^ 6481** 6482** ^The sqlite3_status() and sqlite3_status64() routines return 6483** SQLITE_OK on success and a non-zero [error code] on failure. 6484** 6485** If either the current value or the highwater mark is too large to 6486** be represented by a 32-bit integer, then the values returned by 6487** sqlite3_status() are undefined. 6488** 6489** See also: [sqlite3_db_status()] 6490*/ 6491int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6492int sqlite3_status64( 6493 int op, 6494 sqlite3_int64 *pCurrent, 6495 sqlite3_int64 *pHighwater, 6496 int resetFlag 6497); 6498 6499 6500/* 6501** CAPI3REF: Status Parameters 6502** KEYWORDS: {status parameters} 6503** 6504** These integer constants designate various run-time status parameters 6505** that can be returned by [sqlite3_status()]. 6506** 6507** <dl> 6508** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6509** <dd>This parameter is the current amount of memory checked out 6510** using [sqlite3_malloc()], either directly or indirectly. The 6511** figure includes calls made to [sqlite3_malloc()] by the application 6512** and internal memory usage by the SQLite library. Scratch memory 6513** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6514** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6515** this parameter. The amount returned is the sum of the allocation 6516** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6517** 6518** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6519** <dd>This parameter records the largest memory allocation request 6520** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6521** internal equivalents). Only the value returned in the 6522** *pHighwater parameter to [sqlite3_status()] is of interest. 6523** The value written into the *pCurrent parameter is undefined.</dd>)^ 6524** 6525** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6526** <dd>This parameter records the number of separate memory allocations 6527** currently checked out.</dd>)^ 6528** 6529** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6530** <dd>This parameter returns the number of pages used out of the 6531** [pagecache memory allocator] that was configured using 6532** [SQLITE_CONFIG_PAGECACHE]. The 6533** value returned is in pages, not in bytes.</dd>)^ 6534** 6535** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6536** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6537** <dd>This parameter returns the number of bytes of page cache 6538** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6539** buffer and where forced to overflow to [sqlite3_malloc()]. The 6540** returned value includes allocations that overflowed because they 6541** where too large (they were larger than the "sz" parameter to 6542** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6543** no space was left in the page cache.</dd>)^ 6544** 6545** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6546** <dd>This parameter records the largest memory allocation request 6547** handed to [pagecache memory allocator]. Only the value returned in the 6548** *pHighwater parameter to [sqlite3_status()] is of interest. 6549** The value written into the *pCurrent parameter is undefined.</dd>)^ 6550** 6551** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6552** <dd>This parameter returns the number of allocations used out of the 6553** [scratch memory allocator] configured using 6554** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6555** in bytes. Since a single thread may only have one scratch allocation 6556** outstanding at time, this parameter also reports the number of threads 6557** using scratch memory at the same time.</dd>)^ 6558** 6559** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6560** <dd>This parameter returns the number of bytes of scratch memory 6561** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6562** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6563** returned include overflows because the requested allocation was too 6564** larger (that is, because the requested allocation was larger than the 6565** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6566** slots were available. 6567** </dd>)^ 6568** 6569** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6570** <dd>This parameter records the largest memory allocation request 6571** handed to [scratch memory allocator]. Only the value returned in the 6572** *pHighwater parameter to [sqlite3_status()] is of interest. 6573** The value written into the *pCurrent parameter is undefined.</dd>)^ 6574** 6575** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6576** <dd>The *pHighwater parameter records the deepest parser stack. 6577** The *pCurrent value is undefined. The *pHighwater value is only 6578** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6579** </dl> 6580** 6581** New status parameters may be added from time to time. 6582*/ 6583#define SQLITE_STATUS_MEMORY_USED 0 6584#define SQLITE_STATUS_PAGECACHE_USED 1 6585#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6586#define SQLITE_STATUS_SCRATCH_USED 3 6587#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6588#define SQLITE_STATUS_MALLOC_SIZE 5 6589#define SQLITE_STATUS_PARSER_STACK 6 6590#define SQLITE_STATUS_PAGECACHE_SIZE 7 6591#define SQLITE_STATUS_SCRATCH_SIZE 8 6592#define SQLITE_STATUS_MALLOC_COUNT 9 6593 6594/* 6595** CAPI3REF: Database Connection Status 6596** METHOD: sqlite3 6597** 6598** ^This interface is used to retrieve runtime status information 6599** about a single [database connection]. ^The first argument is the 6600** database connection object to be interrogated. ^The second argument 6601** is an integer constant, taken from the set of 6602** [SQLITE_DBSTATUS options], that 6603** determines the parameter to interrogate. The set of 6604** [SQLITE_DBSTATUS options] is likely 6605** to grow in future releases of SQLite. 6606** 6607** ^The current value of the requested parameter is written into *pCur 6608** and the highest instantaneous value is written into *pHiwtr. ^If 6609** the resetFlg is true, then the highest instantaneous value is 6610** reset back down to the current value. 6611** 6612** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6613** non-zero [error code] on failure. 6614** 6615** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6616*/ 6617int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6618 6619/* 6620** CAPI3REF: Status Parameters for database connections 6621** KEYWORDS: {SQLITE_DBSTATUS options} 6622** 6623** These constants are the available integer "verbs" that can be passed as 6624** the second argument to the [sqlite3_db_status()] interface. 6625** 6626** New verbs may be added in future releases of SQLite. Existing verbs 6627** might be discontinued. Applications should check the return code from 6628** [sqlite3_db_status()] to make sure that the call worked. 6629** The [sqlite3_db_status()] interface will return a non-zero error code 6630** if a discontinued or unsupported verb is invoked. 6631** 6632** <dl> 6633** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6634** <dd>This parameter returns the number of lookaside memory slots currently 6635** checked out.</dd>)^ 6636** 6637** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6638** <dd>This parameter returns the number malloc attempts that were 6639** satisfied using lookaside memory. Only the high-water value is meaningful; 6640** the current value is always zero.)^ 6641** 6642** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6643** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6644** <dd>This parameter returns the number malloc attempts that might have 6645** been satisfied using lookaside memory but failed due to the amount of 6646** memory requested being larger than the lookaside slot size. 6647** Only the high-water value is meaningful; 6648** the current value is always zero.)^ 6649** 6650** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6651** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6652** <dd>This parameter returns the number malloc attempts that might have 6653** been satisfied using lookaside memory but failed due to all lookaside 6654** memory already being in use. 6655** Only the high-water value is meaningful; 6656** the current value is always zero.)^ 6657** 6658** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6659** <dd>This parameter returns the approximate number of bytes of heap 6660** memory used by all pager caches associated with the database connection.)^ 6661** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6662** 6663** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6664** <dd>This parameter returns the approximate number of bytes of heap 6665** memory used to store the schema for all databases associated 6666** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6667** ^The full amount of memory used by the schemas is reported, even if the 6668** schema memory is shared with other database connections due to 6669** [shared cache mode] being enabled. 6670** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6671** 6672** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6673** <dd>This parameter returns the approximate number of bytes of heap 6674** and lookaside memory used by all prepared statements associated with 6675** the database connection.)^ 6676** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6677** </dd> 6678** 6679** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6680** <dd>This parameter returns the number of pager cache hits that have 6681** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6682** is always 0. 6683** </dd> 6684** 6685** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6686** <dd>This parameter returns the number of pager cache misses that have 6687** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6688** is always 0. 6689** </dd> 6690** 6691** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6692** <dd>This parameter returns the number of dirty cache entries that have 6693** been written to disk. Specifically, the number of pages written to the 6694** wal file in wal mode databases, or the number of pages written to the 6695** database file in rollback mode databases. Any pages written as part of 6696** transaction rollback or database recovery operations are not included. 6697** If an IO or other error occurs while writing a page to disk, the effect 6698** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6699** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6700** </dd> 6701** 6702** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 6703** <dd>This parameter returns zero for the current value if and only if 6704** all foreign key constraints (deferred or immediate) have been 6705** resolved.)^ ^The highwater mark is always 0. 6706** </dd> 6707** </dl> 6708*/ 6709#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6710#define SQLITE_DBSTATUS_CACHE_USED 1 6711#define SQLITE_DBSTATUS_SCHEMA_USED 2 6712#define SQLITE_DBSTATUS_STMT_USED 3 6713#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6714#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6715#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6716#define SQLITE_DBSTATUS_CACHE_HIT 7 6717#define SQLITE_DBSTATUS_CACHE_MISS 8 6718#define SQLITE_DBSTATUS_CACHE_WRITE 9 6719#define SQLITE_DBSTATUS_DEFERRED_FKS 10 6720#define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */ 6721 6722 6723/* 6724** CAPI3REF: Prepared Statement Status 6725** METHOD: sqlite3_stmt 6726** 6727** ^(Each prepared statement maintains various 6728** [SQLITE_STMTSTATUS counters] that measure the number 6729** of times it has performed specific operations.)^ These counters can 6730** be used to monitor the performance characteristics of the prepared 6731** statements. For example, if the number of table steps greatly exceeds 6732** the number of table searches or result rows, that would tend to indicate 6733** that the prepared statement is using a full table scan rather than 6734** an index. 6735** 6736** ^(This interface is used to retrieve and reset counter values from 6737** a [prepared statement]. The first argument is the prepared statement 6738** object to be interrogated. The second argument 6739** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6740** to be interrogated.)^ 6741** ^The current value of the requested counter is returned. 6742** ^If the resetFlg is true, then the counter is reset to zero after this 6743** interface call returns. 6744** 6745** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6746*/ 6747int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6748 6749/* 6750** CAPI3REF: Status Parameters for prepared statements 6751** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6752** 6753** These preprocessor macros define integer codes that name counter 6754** values associated with the [sqlite3_stmt_status()] interface. 6755** The meanings of the various counters are as follows: 6756** 6757** <dl> 6758** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6759** <dd>^This is the number of times that SQLite has stepped forward in 6760** a table as part of a full table scan. Large numbers for this counter 6761** may indicate opportunities for performance improvement through 6762** careful use of indices.</dd> 6763** 6764** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6765** <dd>^This is the number of sort operations that have occurred. 6766** A non-zero value in this counter may indicate an opportunity to 6767** improvement performance through careful use of indices.</dd> 6768** 6769** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6770** <dd>^This is the number of rows inserted into transient indices that 6771** were created automatically in order to help joins run faster. 6772** A non-zero value in this counter may indicate an opportunity to 6773** improvement performance by adding permanent indices that do not 6774** need to be reinitialized each time the statement is run.</dd> 6775** 6776** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 6777** <dd>^This is the number of virtual machine operations executed 6778** by the prepared statement if that number is less than or equal 6779** to 2147483647. The number of virtual machine operations can be 6780** used as a proxy for the total work done by the prepared statement. 6781** If the number of virtual machine operations exceeds 2147483647 6782** then the value returned by this statement status code is undefined. 6783** </dd> 6784** </dl> 6785*/ 6786#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6787#define SQLITE_STMTSTATUS_SORT 2 6788#define SQLITE_STMTSTATUS_AUTOINDEX 3 6789#define SQLITE_STMTSTATUS_VM_STEP 4 6790 6791/* 6792** CAPI3REF: Custom Page Cache Object 6793** 6794** The sqlite3_pcache type is opaque. It is implemented by 6795** the pluggable module. The SQLite core has no knowledge of 6796** its size or internal structure and never deals with the 6797** sqlite3_pcache object except by holding and passing pointers 6798** to the object. 6799** 6800** See [sqlite3_pcache_methods2] for additional information. 6801*/ 6802typedef struct sqlite3_pcache sqlite3_pcache; 6803 6804/* 6805** CAPI3REF: Custom Page Cache Object 6806** 6807** The sqlite3_pcache_page object represents a single page in the 6808** page cache. The page cache will allocate instances of this 6809** object. Various methods of the page cache use pointers to instances 6810** of this object as parameters or as their return value. 6811** 6812** See [sqlite3_pcache_methods2] for additional information. 6813*/ 6814typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6815struct sqlite3_pcache_page { 6816 void *pBuf; /* The content of the page */ 6817 void *pExtra; /* Extra information associated with the page */ 6818}; 6819 6820/* 6821** CAPI3REF: Application Defined Page Cache. 6822** KEYWORDS: {page cache} 6823** 6824** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6825** register an alternative page cache implementation by passing in an 6826** instance of the sqlite3_pcache_methods2 structure.)^ 6827** In many applications, most of the heap memory allocated by 6828** SQLite is used for the page cache. 6829** By implementing a 6830** custom page cache using this API, an application can better control 6831** the amount of memory consumed by SQLite, the way in which 6832** that memory is allocated and released, and the policies used to 6833** determine exactly which parts of a database file are cached and for 6834** how long. 6835** 6836** The alternative page cache mechanism is an 6837** extreme measure that is only needed by the most demanding applications. 6838** The built-in page cache is recommended for most uses. 6839** 6840** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6841** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6842** the application may discard the parameter after the call to 6843** [sqlite3_config()] returns.)^ 6844** 6845** [[the xInit() page cache method]] 6846** ^(The xInit() method is called once for each effective 6847** call to [sqlite3_initialize()])^ 6848** (usually only once during the lifetime of the process). ^(The xInit() 6849** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6850** The intent of the xInit() method is to set up global data structures 6851** required by the custom page cache implementation. 6852** ^(If the xInit() method is NULL, then the 6853** built-in default page cache is used instead of the application defined 6854** page cache.)^ 6855** 6856** [[the xShutdown() page cache method]] 6857** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6858** It can be used to clean up 6859** any outstanding resources before process shutdown, if required. 6860** ^The xShutdown() method may be NULL. 6861** 6862** ^SQLite automatically serializes calls to the xInit method, 6863** so the xInit method need not be threadsafe. ^The 6864** xShutdown method is only called from [sqlite3_shutdown()] so it does 6865** not need to be threadsafe either. All other methods must be threadsafe 6866** in multithreaded applications. 6867** 6868** ^SQLite will never invoke xInit() more than once without an intervening 6869** call to xShutdown(). 6870** 6871** [[the xCreate() page cache methods]] 6872** ^SQLite invokes the xCreate() method to construct a new cache instance. 6873** SQLite will typically create one cache instance for each open database file, 6874** though this is not guaranteed. ^The 6875** first parameter, szPage, is the size in bytes of the pages that must 6876** be allocated by the cache. ^szPage will always a power of two. ^The 6877** second parameter szExtra is a number of bytes of extra storage 6878** associated with each page cache entry. ^The szExtra parameter will 6879** a number less than 250. SQLite will use the 6880** extra szExtra bytes on each page to store metadata about the underlying 6881** database page on disk. The value passed into szExtra depends 6882** on the SQLite version, the target platform, and how SQLite was compiled. 6883** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6884** created will be used to cache database pages of a file stored on disk, or 6885** false if it is used for an in-memory database. The cache implementation 6886** does not have to do anything special based with the value of bPurgeable; 6887** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6888** never invoke xUnpin() except to deliberately delete a page. 6889** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6890** false will always have the "discard" flag set to true. 6891** ^Hence, a cache created with bPurgeable false will 6892** never contain any unpinned pages. 6893** 6894** [[the xCachesize() page cache method]] 6895** ^(The xCachesize() method may be called at any time by SQLite to set the 6896** suggested maximum cache-size (number of pages stored by) the cache 6897** instance passed as the first argument. This is the value configured using 6898** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6899** parameter, the implementation is not required to do anything with this 6900** value; it is advisory only. 6901** 6902** [[the xPagecount() page cache methods]] 6903** The xPagecount() method must return the number of pages currently 6904** stored in the cache, both pinned and unpinned. 6905** 6906** [[the xFetch() page cache methods]] 6907** The xFetch() method locates a page in the cache and returns a pointer to 6908** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6909** The pBuf element of the returned sqlite3_pcache_page object will be a 6910** pointer to a buffer of szPage bytes used to store the content of a 6911** single database page. The pExtra element of sqlite3_pcache_page will be 6912** a pointer to the szExtra bytes of extra storage that SQLite has requested 6913** for each entry in the page cache. 6914** 6915** The page to be fetched is determined by the key. ^The minimum key value 6916** is 1. After it has been retrieved using xFetch, the page is considered 6917** to be "pinned". 6918** 6919** If the requested page is already in the page cache, then the page cache 6920** implementation must return a pointer to the page buffer with its content 6921** intact. If the requested page is not already in the cache, then the 6922** cache implementation should use the value of the createFlag 6923** parameter to help it determined what action to take: 6924** 6925** <table border=1 width=85% align=center> 6926** <tr><th> createFlag <th> Behavior when page is not already in cache 6927** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6928** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6929** Otherwise return NULL. 6930** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6931** NULL if allocating a new page is effectively impossible. 6932** </table> 6933** 6934** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6935** will only use a createFlag of 2 after a prior call with a createFlag of 1 6936** failed.)^ In between the to xFetch() calls, SQLite may 6937** attempt to unpin one or more cache pages by spilling the content of 6938** pinned pages to disk and synching the operating system disk cache. 6939** 6940** [[the xUnpin() page cache method]] 6941** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6942** as its second argument. If the third parameter, discard, is non-zero, 6943** then the page must be evicted from the cache. 6944** ^If the discard parameter is 6945** zero, then the page may be discarded or retained at the discretion of 6946** page cache implementation. ^The page cache implementation 6947** may choose to evict unpinned pages at any time. 6948** 6949** The cache must not perform any reference counting. A single 6950** call to xUnpin() unpins the page regardless of the number of prior calls 6951** to xFetch(). 6952** 6953** [[the xRekey() page cache methods]] 6954** The xRekey() method is used to change the key value associated with the 6955** page passed as the second argument. If the cache 6956** previously contains an entry associated with newKey, it must be 6957** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6958** to be pinned. 6959** 6960** When SQLite calls the xTruncate() method, the cache must discard all 6961** existing cache entries with page numbers (keys) greater than or equal 6962** to the value of the iLimit parameter passed to xTruncate(). If any 6963** of these pages are pinned, they are implicitly unpinned, meaning that 6964** they can be safely discarded. 6965** 6966** [[the xDestroy() page cache method]] 6967** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6968** All resources associated with the specified cache should be freed. ^After 6969** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6970** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6971** functions. 6972** 6973** [[the xShrink() page cache method]] 6974** ^SQLite invokes the xShrink() method when it wants the page cache to 6975** free up as much of heap memory as possible. The page cache implementation 6976** is not obligated to free any memory, but well-behaved implementations should 6977** do their best. 6978*/ 6979typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6980struct sqlite3_pcache_methods2 { 6981 int iVersion; 6982 void *pArg; 6983 int (*xInit)(void*); 6984 void (*xShutdown)(void*); 6985 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6986 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6987 int (*xPagecount)(sqlite3_pcache*); 6988 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6989 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6990 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6991 unsigned oldKey, unsigned newKey); 6992 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6993 void (*xDestroy)(sqlite3_pcache*); 6994 void (*xShrink)(sqlite3_pcache*); 6995}; 6996 6997/* 6998** This is the obsolete pcache_methods object that has now been replaced 6999** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7000** retained in the header file for backwards compatibility only. 7001*/ 7002typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7003struct sqlite3_pcache_methods { 7004 void *pArg; 7005 int (*xInit)(void*); 7006 void (*xShutdown)(void*); 7007 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7008 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7009 int (*xPagecount)(sqlite3_pcache*); 7010 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7011 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7012 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7013 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7014 void (*xDestroy)(sqlite3_pcache*); 7015}; 7016 7017 7018/* 7019** CAPI3REF: Online Backup Object 7020** 7021** The sqlite3_backup object records state information about an ongoing 7022** online backup operation. ^The sqlite3_backup object is created by 7023** a call to [sqlite3_backup_init()] and is destroyed by a call to 7024** [sqlite3_backup_finish()]. 7025** 7026** See Also: [Using the SQLite Online Backup API] 7027*/ 7028typedef struct sqlite3_backup sqlite3_backup; 7029 7030/* 7031** CAPI3REF: Online Backup API. 7032** 7033** The backup API copies the content of one database into another. 7034** It is useful either for creating backups of databases or 7035** for copying in-memory databases to or from persistent files. 7036** 7037** See Also: [Using the SQLite Online Backup API] 7038** 7039** ^SQLite holds a write transaction open on the destination database file 7040** for the duration of the backup operation. 7041** ^The source database is read-locked only while it is being read; 7042** it is not locked continuously for the entire backup operation. 7043** ^Thus, the backup may be performed on a live source database without 7044** preventing other database connections from 7045** reading or writing to the source database while the backup is underway. 7046** 7047** ^(To perform a backup operation: 7048** <ol> 7049** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7050** backup, 7051** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7052** the data between the two databases, and finally 7053** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7054** associated with the backup operation. 7055** </ol>)^ 7056** There should be exactly one call to sqlite3_backup_finish() for each 7057** successful call to sqlite3_backup_init(). 7058** 7059** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7060** 7061** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7062** [database connection] associated with the destination database 7063** and the database name, respectively. 7064** ^The database name is "main" for the main database, "temp" for the 7065** temporary database, or the name specified after the AS keyword in 7066** an [ATTACH] statement for an attached database. 7067** ^The S and M arguments passed to 7068** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7069** and database name of the source database, respectively. 7070** ^The source and destination [database connections] (parameters S and D) 7071** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7072** an error. 7073** 7074** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if 7075** there is already a read or read-write transaction open on the 7076** destination database. 7077** 7078** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7079** returned and an error code and error message are stored in the 7080** destination [database connection] D. 7081** ^The error code and message for the failed call to sqlite3_backup_init() 7082** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7083** [sqlite3_errmsg16()] functions. 7084** ^A successful call to sqlite3_backup_init() returns a pointer to an 7085** [sqlite3_backup] object. 7086** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7087** sqlite3_backup_finish() functions to perform the specified backup 7088** operation. 7089** 7090** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7091** 7092** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7093** the source and destination databases specified by [sqlite3_backup] object B. 7094** ^If N is negative, all remaining source pages are copied. 7095** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7096** are still more pages to be copied, then the function returns [SQLITE_OK]. 7097** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7098** from source to destination, then it returns [SQLITE_DONE]. 7099** ^If an error occurs while running sqlite3_backup_step(B,N), 7100** then an [error code] is returned. ^As well as [SQLITE_OK] and 7101** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7102** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7103** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7104** 7105** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7106** <ol> 7107** <li> the destination database was opened read-only, or 7108** <li> the destination database is using write-ahead-log journaling 7109** and the destination and source page sizes differ, or 7110** <li> the destination database is an in-memory database and the 7111** destination and source page sizes differ. 7112** </ol>)^ 7113** 7114** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7115** the [sqlite3_busy_handler | busy-handler function] 7116** is invoked (if one is specified). ^If the 7117** busy-handler returns non-zero before the lock is available, then 7118** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7119** sqlite3_backup_step() can be retried later. ^If the source 7120** [database connection] 7121** is being used to write to the source database when sqlite3_backup_step() 7122** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7123** case the call to sqlite3_backup_step() can be retried later on. ^(If 7124** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7125** [SQLITE_READONLY] is returned, then 7126** there is no point in retrying the call to sqlite3_backup_step(). These 7127** errors are considered fatal.)^ The application must accept 7128** that the backup operation has failed and pass the backup operation handle 7129** to the sqlite3_backup_finish() to release associated resources. 7130** 7131** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7132** on the destination file. ^The exclusive lock is not released until either 7133** sqlite3_backup_finish() is called or the backup operation is complete 7134** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7135** sqlite3_backup_step() obtains a [shared lock] on the source database that 7136** lasts for the duration of the sqlite3_backup_step() call. 7137** ^Because the source database is not locked between calls to 7138** sqlite3_backup_step(), the source database may be modified mid-way 7139** through the backup process. ^If the source database is modified by an 7140** external process or via a database connection other than the one being 7141** used by the backup operation, then the backup will be automatically 7142** restarted by the next call to sqlite3_backup_step(). ^If the source 7143** database is modified by the using the same database connection as is used 7144** by the backup operation, then the backup database is automatically 7145** updated at the same time. 7146** 7147** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7148** 7149** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7150** application wishes to abandon the backup operation, the application 7151** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7152** ^The sqlite3_backup_finish() interfaces releases all 7153** resources associated with the [sqlite3_backup] object. 7154** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7155** active write-transaction on the destination database is rolled back. 7156** The [sqlite3_backup] object is invalid 7157** and may not be used following a call to sqlite3_backup_finish(). 7158** 7159** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7160** sqlite3_backup_step() errors occurred, regardless or whether or not 7161** sqlite3_backup_step() completed. 7162** ^If an out-of-memory condition or IO error occurred during any prior 7163** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7164** sqlite3_backup_finish() returns the corresponding [error code]. 7165** 7166** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7167** is not a permanent error and does not affect the return value of 7168** sqlite3_backup_finish(). 7169** 7170** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7171** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7172** 7173** ^The sqlite3_backup_remaining() routine returns the number of pages still 7174** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7175** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7176** in the source database at the conclusion of the most recent 7177** sqlite3_backup_step(). 7178** ^(The values returned by these functions are only updated by 7179** sqlite3_backup_step(). If the source database is modified in a way that 7180** changes the size of the source database or the number of pages remaining, 7181** those changes are not reflected in the output of sqlite3_backup_pagecount() 7182** and sqlite3_backup_remaining() until after the next 7183** sqlite3_backup_step().)^ 7184** 7185** <b>Concurrent Usage of Database Handles</b> 7186** 7187** ^The source [database connection] may be used by the application for other 7188** purposes while a backup operation is underway or being initialized. 7189** ^If SQLite is compiled and configured to support threadsafe database 7190** connections, then the source database connection may be used concurrently 7191** from within other threads. 7192** 7193** However, the application must guarantee that the destination 7194** [database connection] is not passed to any other API (by any thread) after 7195** sqlite3_backup_init() is called and before the corresponding call to 7196** sqlite3_backup_finish(). SQLite does not currently check to see 7197** if the application incorrectly accesses the destination [database connection] 7198** and so no error code is reported, but the operations may malfunction 7199** nevertheless. Use of the destination database connection while a 7200** backup is in progress might also also cause a mutex deadlock. 7201** 7202** If running in [shared cache mode], the application must 7203** guarantee that the shared cache used by the destination database 7204** is not accessed while the backup is running. In practice this means 7205** that the application must guarantee that the disk file being 7206** backed up to is not accessed by any connection within the process, 7207** not just the specific connection that was passed to sqlite3_backup_init(). 7208** 7209** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7210** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7211** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7212** APIs are not strictly speaking threadsafe. If they are invoked at the 7213** same time as another thread is invoking sqlite3_backup_step() it is 7214** possible that they return invalid values. 7215*/ 7216sqlite3_backup *sqlite3_backup_init( 7217 sqlite3 *pDest, /* Destination database handle */ 7218 const char *zDestName, /* Destination database name */ 7219 sqlite3 *pSource, /* Source database handle */ 7220 const char *zSourceName /* Source database name */ 7221); 7222int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7223int sqlite3_backup_finish(sqlite3_backup *p); 7224int sqlite3_backup_remaining(sqlite3_backup *p); 7225int sqlite3_backup_pagecount(sqlite3_backup *p); 7226 7227/* 7228** CAPI3REF: Unlock Notification 7229** METHOD: sqlite3 7230** 7231** ^When running in shared-cache mode, a database operation may fail with 7232** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7233** individual tables within the shared-cache cannot be obtained. See 7234** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7235** ^This API may be used to register a callback that SQLite will invoke 7236** when the connection currently holding the required lock relinquishes it. 7237** ^This API is only available if the library was compiled with the 7238** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7239** 7240** See Also: [Using the SQLite Unlock Notification Feature]. 7241** 7242** ^Shared-cache locks are released when a database connection concludes 7243** its current transaction, either by committing it or rolling it back. 7244** 7245** ^When a connection (known as the blocked connection) fails to obtain a 7246** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7247** identity of the database connection (the blocking connection) that 7248** has locked the required resource is stored internally. ^After an 7249** application receives an SQLITE_LOCKED error, it may call the 7250** sqlite3_unlock_notify() method with the blocked connection handle as 7251** the first argument to register for a callback that will be invoked 7252** when the blocking connections current transaction is concluded. ^The 7253** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7254** call that concludes the blocking connections transaction. 7255** 7256** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7257** there is a chance that the blocking connection will have already 7258** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7259** If this happens, then the specified callback is invoked immediately, 7260** from within the call to sqlite3_unlock_notify().)^ 7261** 7262** ^If the blocked connection is attempting to obtain a write-lock on a 7263** shared-cache table, and more than one other connection currently holds 7264** a read-lock on the same table, then SQLite arbitrarily selects one of 7265** the other connections to use as the blocking connection. 7266** 7267** ^(There may be at most one unlock-notify callback registered by a 7268** blocked connection. If sqlite3_unlock_notify() is called when the 7269** blocked connection already has a registered unlock-notify callback, 7270** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7271** called with a NULL pointer as its second argument, then any existing 7272** unlock-notify callback is canceled. ^The blocked connections 7273** unlock-notify callback may also be canceled by closing the blocked 7274** connection using [sqlite3_close()]. 7275** 7276** The unlock-notify callback is not reentrant. If an application invokes 7277** any sqlite3_xxx API functions from within an unlock-notify callback, a 7278** crash or deadlock may be the result. 7279** 7280** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7281** returns SQLITE_OK. 7282** 7283** <b>Callback Invocation Details</b> 7284** 7285** When an unlock-notify callback is registered, the application provides a 7286** single void* pointer that is passed to the callback when it is invoked. 7287** However, the signature of the callback function allows SQLite to pass 7288** it an array of void* context pointers. The first argument passed to 7289** an unlock-notify callback is a pointer to an array of void* pointers, 7290** and the second is the number of entries in the array. 7291** 7292** When a blocking connections transaction is concluded, there may be 7293** more than one blocked connection that has registered for an unlock-notify 7294** callback. ^If two or more such blocked connections have specified the 7295** same callback function, then instead of invoking the callback function 7296** multiple times, it is invoked once with the set of void* context pointers 7297** specified by the blocked connections bundled together into an array. 7298** This gives the application an opportunity to prioritize any actions 7299** related to the set of unblocked database connections. 7300** 7301** <b>Deadlock Detection</b> 7302** 7303** Assuming that after registering for an unlock-notify callback a 7304** database waits for the callback to be issued before taking any further 7305** action (a reasonable assumption), then using this API may cause the 7306** application to deadlock. For example, if connection X is waiting for 7307** connection Y's transaction to be concluded, and similarly connection 7308** Y is waiting on connection X's transaction, then neither connection 7309** will proceed and the system may remain deadlocked indefinitely. 7310** 7311** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7312** detection. ^If a given call to sqlite3_unlock_notify() would put the 7313** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7314** unlock-notify callback is registered. The system is said to be in 7315** a deadlocked state if connection A has registered for an unlock-notify 7316** callback on the conclusion of connection B's transaction, and connection 7317** B has itself registered for an unlock-notify callback when connection 7318** A's transaction is concluded. ^Indirect deadlock is also detected, so 7319** the system is also considered to be deadlocked if connection B has 7320** registered for an unlock-notify callback on the conclusion of connection 7321** C's transaction, where connection C is waiting on connection A. ^Any 7322** number of levels of indirection are allowed. 7323** 7324** <b>The "DROP TABLE" Exception</b> 7325** 7326** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7327** always appropriate to call sqlite3_unlock_notify(). There is however, 7328** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7329** SQLite checks if there are any currently executing SELECT statements 7330** that belong to the same connection. If there are, SQLITE_LOCKED is 7331** returned. In this case there is no "blocking connection", so invoking 7332** sqlite3_unlock_notify() results in the unlock-notify callback being 7333** invoked immediately. If the application then re-attempts the "DROP TABLE" 7334** or "DROP INDEX" query, an infinite loop might be the result. 7335** 7336** One way around this problem is to check the extended error code returned 7337** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7338** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7339** the special "DROP TABLE/INDEX" case, the extended error code is just 7340** SQLITE_LOCKED.)^ 7341*/ 7342int sqlite3_unlock_notify( 7343 sqlite3 *pBlocked, /* Waiting connection */ 7344 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7345 void *pNotifyArg /* Argument to pass to xNotify */ 7346); 7347 7348 7349/* 7350** CAPI3REF: String Comparison 7351** 7352** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7353** and extensions to compare the contents of two buffers containing UTF-8 7354** strings in a case-independent fashion, using the same definition of "case 7355** independence" that SQLite uses internally when comparing identifiers. 7356*/ 7357int sqlite3_stricmp(const char *, const char *); 7358int sqlite3_strnicmp(const char *, const char *, int); 7359 7360/* 7361** CAPI3REF: String Globbing 7362* 7363** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches 7364** the glob pattern P, and it returns non-zero if string X does not match 7365** the glob pattern P. ^The definition of glob pattern matching used in 7366** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7367** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case 7368** sensitive. 7369** 7370** Note that this routine returns zero on a match and non-zero if the strings 7371** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7372*/ 7373int sqlite3_strglob(const char *zGlob, const char *zStr); 7374 7375/* 7376** CAPI3REF: Error Logging Interface 7377** 7378** ^The [sqlite3_log()] interface writes a message into the [error log] 7379** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7380** ^If logging is enabled, the zFormat string and subsequent arguments are 7381** used with [sqlite3_snprintf()] to generate the final output string. 7382** 7383** The sqlite3_log() interface is intended for use by extensions such as 7384** virtual tables, collating functions, and SQL functions. While there is 7385** nothing to prevent an application from calling sqlite3_log(), doing so 7386** is considered bad form. 7387** 7388** The zFormat string must not be NULL. 7389** 7390** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7391** will not use dynamically allocated memory. The log message is stored in 7392** a fixed-length buffer on the stack. If the log message is longer than 7393** a few hundred characters, it will be truncated to the length of the 7394** buffer. 7395*/ 7396void sqlite3_log(int iErrCode, const char *zFormat, ...); 7397 7398/* 7399** CAPI3REF: Write-Ahead Log Commit Hook 7400** METHOD: sqlite3 7401** 7402** ^The [sqlite3_wal_hook()] function is used to register a callback that 7403** is invoked each time data is committed to a database in wal mode. 7404** 7405** ^(The callback is invoked by SQLite after the commit has taken place and 7406** the associated write-lock on the database released)^, so the implementation 7407** may read, write or [checkpoint] the database as required. 7408** 7409** ^The first parameter passed to the callback function when it is invoked 7410** is a copy of the third parameter passed to sqlite3_wal_hook() when 7411** registering the callback. ^The second is a copy of the database handle. 7412** ^The third parameter is the name of the database that was written to - 7413** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7414** is the number of pages currently in the write-ahead log file, 7415** including those that were just committed. 7416** 7417** The callback function should normally return [SQLITE_OK]. ^If an error 7418** code is returned, that error will propagate back up through the 7419** SQLite code base to cause the statement that provoked the callback 7420** to report an error, though the commit will have still occurred. If the 7421** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7422** that does not correspond to any valid SQLite error code, the results 7423** are undefined. 7424** 7425** A single database handle may have at most a single write-ahead log callback 7426** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7427** previously registered write-ahead log callback. ^Note that the 7428** [sqlite3_wal_autocheckpoint()] interface and the 7429** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7430** those overwrite any prior [sqlite3_wal_hook()] settings. 7431*/ 7432void *sqlite3_wal_hook( 7433 sqlite3*, 7434 int(*)(void *,sqlite3*,const char*,int), 7435 void* 7436); 7437 7438/* 7439** CAPI3REF: Configure an auto-checkpoint 7440** METHOD: sqlite3 7441** 7442** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 7443** [sqlite3_wal_hook()] that causes any database on [database connection] D 7444** to automatically [checkpoint] 7445** after committing a transaction if there are N or 7446** more frames in the [write-ahead log] file. ^Passing zero or 7447** a negative value as the nFrame parameter disables automatic 7448** checkpoints entirely. 7449** 7450** ^The callback registered by this function replaces any existing callback 7451** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 7452** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 7453** configured by this function. 7454** 7455** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 7456** from SQL. 7457** 7458** ^Checkpoints initiated by this mechanism are 7459** [sqlite3_wal_checkpoint_v2|PASSIVE]. 7460** 7461** ^Every new [database connection] defaults to having the auto-checkpoint 7462** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 7463** pages. The use of this interface 7464** is only necessary if the default setting is found to be suboptimal 7465** for a particular application. 7466*/ 7467int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 7468 7469/* 7470** CAPI3REF: Checkpoint a database 7471** METHOD: sqlite3 7472** 7473** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 7474** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 7475** 7476** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 7477** [write-ahead log] for database X on [database connection] D to be 7478** transferred into the database file and for the write-ahead log to 7479** be reset. See the [checkpointing] documentation for addition 7480** information. 7481** 7482** This interface used to be the only way to cause a checkpoint to 7483** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 7484** interface was added. This interface is retained for backwards 7485** compatibility and as a convenience for applications that need to manually 7486** start a callback but which do not need the full power (and corresponding 7487** complication) of [sqlite3_wal_checkpoint_v2()]. 7488*/ 7489int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 7490 7491/* 7492** CAPI3REF: Checkpoint a database 7493** METHOD: sqlite3 7494** 7495** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 7496** operation on database X of [database connection] D in mode M. Status 7497** information is written back into integers pointed to by L and C.)^ 7498** ^(The M parameter must be a valid [checkpoint mode]:)^ 7499** 7500** <dl> 7501** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7502** ^Checkpoint as many frames as possible without waiting for any database 7503** readers or writers to finish, then sync the database file if all frames 7504** in the log were checkpointed. ^The [busy-handler callback] 7505** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 7506** ^On the other hand, passive mode might leave the checkpoint unfinished 7507** if there are concurrent readers or writers. 7508** 7509** <dt>SQLITE_CHECKPOINT_FULL<dd> 7510** ^This mode blocks (it invokes the 7511** [sqlite3_busy_handler|busy-handler callback]) until there is no 7512** database writer and all readers are reading from the most recent database 7513** snapshot. ^It then checkpoints all frames in the log file and syncs the 7514** database file. ^This mode blocks new database writers while it is pending, 7515** but new database readers are allowed to continue unimpeded. 7516** 7517** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7518** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 7519** that after checkpointing the log file it blocks (calls the 7520** [busy-handler callback]) 7521** until all readers are reading from the database file only. ^This ensures 7522** that the next writer will restart the log file from the beginning. 7523** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 7524** database writer attempts while it is pending, but does not impede readers. 7525** 7526** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 7527** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 7528** addition that it also truncates the log file to zero bytes just prior 7529** to a successful return. 7530** </dl> 7531** 7532** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 7533** the log file or to -1 if the checkpoint could not run because 7534** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 7535** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 7536** log file (including any that were already checkpointed before the function 7537** was called) or to -1 if the checkpoint could not run due to an error or 7538** because the database is not in WAL mode. ^Note that upon successful 7539** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 7540** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 7541** 7542** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 7543** any other process is running a checkpoint operation at the same time, the 7544** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 7545** busy-handler configured, it will not be invoked in this case. 7546** 7547** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 7548** exclusive "writer" lock on the database file. ^If the writer lock cannot be 7549** obtained immediately, and a busy-handler is configured, it is invoked and 7550** the writer lock retried until either the busy-handler returns 0 or the lock 7551** is successfully obtained. ^The busy-handler is also invoked while waiting for 7552** database readers as described above. ^If the busy-handler returns 0 before 7553** the writer lock is obtained or while waiting for database readers, the 7554** checkpoint operation proceeds from that point in the same way as 7555** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7556** without blocking any further. ^SQLITE_BUSY is returned in this case. 7557** 7558** ^If parameter zDb is NULL or points to a zero length string, then the 7559** specified operation is attempted on all WAL databases [attached] to 7560** [database connection] db. In this case the 7561** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 7562** an SQLITE_BUSY error is encountered when processing one or more of the 7563** attached WAL databases, the operation is still attempted on any remaining 7564** attached databases and SQLITE_BUSY is returned at the end. ^If any other 7565** error occurs while processing an attached database, processing is abandoned 7566** and the error code is returned to the caller immediately. ^If no error 7567** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7568** databases, SQLITE_OK is returned. 7569** 7570** ^If database zDb is the name of an attached database that is not in WAL 7571** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 7572** zDb is not NULL (or a zero length string) and is not the name of any 7573** attached database, SQLITE_ERROR is returned to the caller. 7574** 7575** ^Unless it returns SQLITE_MISUSE, 7576** the sqlite3_wal_checkpoint_v2() interface 7577** sets the error information that is queried by 7578** [sqlite3_errcode()] and [sqlite3_errmsg()]. 7579** 7580** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 7581** from SQL. 7582*/ 7583int sqlite3_wal_checkpoint_v2( 7584 sqlite3 *db, /* Database handle */ 7585 const char *zDb, /* Name of attached database (or NULL) */ 7586 int eMode, /* SQLITE_CHECKPOINT_* value */ 7587 int *pnLog, /* OUT: Size of WAL log in frames */ 7588 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7589); 7590 7591/* 7592** CAPI3REF: Checkpoint Mode Values 7593** KEYWORDS: {checkpoint mode} 7594** 7595** These constants define all valid values for the "checkpoint mode" passed 7596** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 7597** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 7598** meaning of each of these checkpoint modes. 7599*/ 7600#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 7601#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 7602#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 7603#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 7604 7605/* 7606** CAPI3REF: Virtual Table Interface Configuration 7607** 7608** This function may be called by either the [xConnect] or [xCreate] method 7609** of a [virtual table] implementation to configure 7610** various facets of the virtual table interface. 7611** 7612** If this interface is invoked outside the context of an xConnect or 7613** xCreate virtual table method then the behavior is undefined. 7614** 7615** At present, there is only one option that may be configured using 7616** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7617** may be added in the future. 7618*/ 7619int sqlite3_vtab_config(sqlite3*, int op, ...); 7620 7621/* 7622** CAPI3REF: Virtual Table Configuration Options 7623** 7624** These macros define the various options to the 7625** [sqlite3_vtab_config()] interface that [virtual table] implementations 7626** can use to customize and optimize their behavior. 7627** 7628** <dl> 7629** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7630** <dd>Calls of the form 7631** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7632** where X is an integer. If X is zero, then the [virtual table] whose 7633** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7634** support constraints. In this configuration (which is the default) if 7635** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7636** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7637** specified as part of the users SQL statement, regardless of the actual 7638** ON CONFLICT mode specified. 7639** 7640** If X is non-zero, then the virtual table implementation guarantees 7641** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7642** any modifications to internal or persistent data structures have been made. 7643** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7644** is able to roll back a statement or database transaction, and abandon 7645** or continue processing the current SQL statement as appropriate. 7646** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7647** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7648** had been ABORT. 7649** 7650** Virtual table implementations that are required to handle OR REPLACE 7651** must do so within the [xUpdate] method. If a call to the 7652** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7653** CONFLICT policy is REPLACE, the virtual table implementation should 7654** silently replace the appropriate rows within the xUpdate callback and 7655** return SQLITE_OK. Or, if this is not possible, it may return 7656** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7657** constraint handling. 7658** </dl> 7659*/ 7660#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7661 7662/* 7663** CAPI3REF: Determine The Virtual Table Conflict Policy 7664** 7665** This function may only be called from within a call to the [xUpdate] method 7666** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7667** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7668** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7669** of the SQL statement that triggered the call to the [xUpdate] method of the 7670** [virtual table]. 7671*/ 7672int sqlite3_vtab_on_conflict(sqlite3 *); 7673 7674/* 7675** CAPI3REF: Conflict resolution modes 7676** KEYWORDS: {conflict resolution mode} 7677** 7678** These constants are returned by [sqlite3_vtab_on_conflict()] to 7679** inform a [virtual table] implementation what the [ON CONFLICT] mode 7680** is for the SQL statement being evaluated. 7681** 7682** Note that the [SQLITE_IGNORE] constant is also used as a potential 7683** return value from the [sqlite3_set_authorizer()] callback and that 7684** [SQLITE_ABORT] is also a [result code]. 7685*/ 7686#define SQLITE_ROLLBACK 1 7687/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7688#define SQLITE_FAIL 3 7689/* #define SQLITE_ABORT 4 // Also an error code */ 7690#define SQLITE_REPLACE 5 7691 7692/* 7693** CAPI3REF: Prepared Statement Scan Status Opcodes 7694** KEYWORDS: {scanstatus options} 7695** 7696** The following constants can be used for the T parameter to the 7697** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 7698** different metric for sqlite3_stmt_scanstatus() to return. 7699** 7700** When the value returned to V is a string, space to hold that string is 7701** managed by the prepared statement S and will be automatically freed when 7702** S is finalized. 7703** 7704** <dl> 7705** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 7706** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 7707** set to the total number of times that the X-th loop has run.</dd> 7708** 7709** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 7710** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 7711** to the total number of rows examined by all iterations of the X-th loop.</dd> 7712** 7713** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 7714** <dd>^The "double" variable pointed to by the T parameter will be set to the 7715** query planner's estimate for the average number of rows output from each 7716** iteration of the X-th loop. If the query planner's estimates was accurate, 7717** then this value will approximate the quotient NVISIT/NLOOP and the 7718** product of this value for all prior loops with the same SELECTID will 7719** be the NLOOP value for the current loop. 7720** 7721** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 7722** <dd>^The "const char *" variable pointed to by the T parameter will be set 7723** to a zero-terminated UTF-8 string containing the name of the index or table 7724** used for the X-th loop. 7725** 7726** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 7727** <dd>^The "const char *" variable pointed to by the T parameter will be set 7728** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 7729** description for the X-th loop. 7730** 7731** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 7732** <dd>^The "int" variable pointed to by the T parameter will be set to the 7733** "select-id" for the X-th loop. The select-id identifies which query or 7734** subquery the loop is part of. The main query has a select-id of zero. 7735** The select-id is the same value as is output in the first column 7736** of an [EXPLAIN QUERY PLAN] query. 7737** </dl> 7738*/ 7739#define SQLITE_SCANSTAT_NLOOP 0 7740#define SQLITE_SCANSTAT_NVISIT 1 7741#define SQLITE_SCANSTAT_EST 2 7742#define SQLITE_SCANSTAT_NAME 3 7743#define SQLITE_SCANSTAT_EXPLAIN 4 7744#define SQLITE_SCANSTAT_SELECTID 5 7745 7746/* 7747** CAPI3REF: Prepared Statement Scan Status 7748** METHOD: sqlite3_stmt 7749** 7750** This interface returns information about the predicted and measured 7751** performance for pStmt. Advanced applications can use this 7752** interface to compare the predicted and the measured performance and 7753** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 7754** 7755** Since this interface is expected to be rarely used, it is only 7756** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 7757** compile-time option. 7758** 7759** The "iScanStatusOp" parameter determines which status information to return. 7760** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 7761** of this interface is undefined. 7762** ^The requested measurement is written into a variable pointed to by 7763** the "pOut" parameter. 7764** Parameter "idx" identifies the specific loop to retrieve statistics for. 7765** Loops are numbered starting from zero. ^If idx is out of range - less than 7766** zero or greater than or equal to the total number of loops used to implement 7767** the statement - a non-zero value is returned and the variable that pOut 7768** points to is unchanged. 7769** 7770** ^Statistics might not be available for all loops in all statements. ^In cases 7771** where there exist loops with no available statistics, this function behaves 7772** as if the loop did not exist - it returns non-zero and leave the variable 7773** that pOut points to unchanged. 7774** 7775** See also: [sqlite3_stmt_scanstatus_reset()] 7776*/ 7777int sqlite3_stmt_scanstatus( 7778 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 7779 int idx, /* Index of loop to report on */ 7780 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 7781 void *pOut /* Result written here */ 7782); 7783 7784/* 7785** CAPI3REF: Zero Scan-Status Counters 7786** METHOD: sqlite3_stmt 7787** 7788** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 7789** 7790** This API is only available if the library is built with pre-processor 7791** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 7792*/ 7793void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 7794 7795 7796/* 7797** Undo the hack that converts floating point types to integer for 7798** builds on processors without floating point support. 7799*/ 7800#ifdef SQLITE_OMIT_FLOATING_POINT 7801# undef double 7802#endif 7803 7804#ifdef __cplusplus 7805} /* End of the 'extern "C"' block */ 7806#endif 7807#endif /* _SQLITE3_H_ */ 7808