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