sqlite3.h revision 289166
1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are supposed to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef _SQLITE3_H_ 34#define _SQLITE3_H_ 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_STDCALL 58# define SQLITE_STDCALL 59#endif 60 61/* 62** These no-op macros are used in front of interfaces to mark those 63** interfaces as either deprecated or experimental. New applications 64** should not use deprecated interfaces - they are supported for backwards 65** compatibility only. Application writers should be aware that 66** experimental interfaces are subject to change in point releases. 67** 68** These macros used to resolve to various kinds of compiler magic that 69** would generate warning messages when they were used. But that 70** compiler magic ended up generating such a flurry of bug reports 71** that we have taken it all out and gone back to using simple 72** noop macros. 73*/ 74#define SQLITE_DEPRECATED 75#define SQLITE_EXPERIMENTAL 76 77/* 78** Ensure these symbols were not defined by some previous header file. 79*/ 80#ifdef SQLITE_VERSION 81# undef SQLITE_VERSION 82#endif 83#ifdef SQLITE_VERSION_NUMBER 84# undef SQLITE_VERSION_NUMBER 85#endif 86 87/* 88** CAPI3REF: Compile-Time Library Version Numbers 89** 90** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 91** evaluates to a string literal that is the SQLite version in the 92** format "X.Y.Z" where X is the major version number (always 3 for 93** SQLite3) and Y is the minor version number and Z is the release number.)^ 94** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 95** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 96** numbers used in [SQLITE_VERSION].)^ 97** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 98** be larger than the release from which it is derived. Either Y will 99** be held constant and Z will be incremented or else Y will be incremented 100** and Z will be reset to zero. 101** 102** Since version 3.6.18, SQLite source code has been stored in the 103** <a href="http://www.fossil-scm.org/">Fossil configuration management 104** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 105** a string which identifies a particular check-in of SQLite 106** within its configuration management system. ^The SQLITE_SOURCE_ID 107** string contains the date and time of the check-in (UTC) and an SHA1 108** hash of the entire source tree. 109** 110** See also: [sqlite3_libversion()], 111** [sqlite3_libversion_number()], [sqlite3_sourceid()], 112** [sqlite_version()] and [sqlite_source_id()]. 113*/ 114#define SQLITE_VERSION "3.8.11.1" 115#define SQLITE_VERSION_NUMBER 3008011 116#define SQLITE_SOURCE_ID "2015-07-29 20:00:57 cf538e2783e468bbc25e7cb2a9ee64d3e0e80b2f" 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_API SQLITE_EXTERN const char sqlite3_version[]; 149SQLITE_API const char *SQLITE_STDCALL sqlite3_libversion(void); 150SQLITE_API const char *SQLITE_STDCALL sqlite3_sourceid(void); 151SQLITE_API int SQLITE_STDCALL sqlite3_libversion_number(void); 152 153/* 154** CAPI3REF: Run-Time Library Compilation Options Diagnostics 155** 156** ^The sqlite3_compileoption_used() function returns 0 or 1 157** indicating whether the specified option was defined at 158** compile time. ^The SQLITE_ prefix may be omitted from the 159** option name passed to sqlite3_compileoption_used(). 160** 161** ^The sqlite3_compileoption_get() function allows iterating 162** over the list of options that were defined at compile time by 163** returning the N-th compile time option string. ^If N is out of range, 164** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 165** prefix is omitted from any strings returned by 166** sqlite3_compileoption_get(). 167** 168** ^Support for the diagnostic functions sqlite3_compileoption_used() 169** and sqlite3_compileoption_get() may be omitted by specifying the 170** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 171** 172** See also: SQL functions [sqlite_compileoption_used()] and 173** [sqlite_compileoption_get()] and the [compile_options pragma]. 174*/ 175#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 176SQLITE_API int SQLITE_STDCALL sqlite3_compileoption_used(const char *zOptName); 177SQLITE_API const char *SQLITE_STDCALL sqlite3_compileoption_get(int N); 178#endif 179 180/* 181** CAPI3REF: Test To See If The Library Is Threadsafe 182** 183** ^The sqlite3_threadsafe() function returns zero if and only if 184** SQLite was compiled with mutexing code omitted due to the 185** [SQLITE_THREADSAFE] compile-time option being set to 0. 186** 187** SQLite can be compiled with or without mutexes. When 188** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 189** are enabled and SQLite is threadsafe. When the 190** [SQLITE_THREADSAFE] macro is 0, 191** the mutexes are omitted. Without the mutexes, it is not safe 192** to use SQLite concurrently from more than one thread. 193** 194** Enabling mutexes incurs a measurable performance penalty. 195** So if speed is of utmost importance, it makes sense to disable 196** the mutexes. But for maximum safety, mutexes should be enabled. 197** ^The default behavior is for mutexes to be enabled. 198** 199** This interface can be used by an application to make sure that the 200** version of SQLite that it is linking against was compiled with 201** the desired setting of the [SQLITE_THREADSAFE] macro. 202** 203** This interface only reports on the compile-time mutex setting 204** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 205** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 206** can be fully or partially disabled using a call to [sqlite3_config()] 207** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 208** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 209** sqlite3_threadsafe() function shows only the compile-time setting of 210** thread safety, not any run-time changes to that setting made by 211** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 212** is unchanged by calls to sqlite3_config().)^ 213** 214** See the [threading mode] documentation for additional information. 215*/ 216SQLITE_API int SQLITE_STDCALL sqlite3_threadsafe(void); 217 218/* 219** CAPI3REF: Database Connection Handle 220** KEYWORDS: {database connection} {database connections} 221** 222** Each open SQLite database is represented by a pointer to an instance of 223** the opaque structure named "sqlite3". It is useful to think of an sqlite3 224** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 225** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 226** and [sqlite3_close_v2()] are its destructors. There are many other 227** interfaces (such as 228** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 229** [sqlite3_busy_timeout()] to name but three) that are methods on an 230** sqlite3 object. 231*/ 232typedef struct sqlite3 sqlite3; 233 234/* 235** CAPI3REF: 64-Bit Integer Types 236** KEYWORDS: sqlite_int64 sqlite_uint64 237** 238** Because there is no cross-platform way to specify 64-bit integer types 239** SQLite includes typedefs for 64-bit signed and unsigned integers. 240** 241** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 242** The sqlite_int64 and sqlite_uint64 types are supported for backwards 243** compatibility only. 244** 245** ^The sqlite3_int64 and sqlite_int64 types can store integer values 246** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 247** sqlite3_uint64 and sqlite_uint64 types can store integer values 248** between 0 and +18446744073709551615 inclusive. 249*/ 250#ifdef SQLITE_INT64_TYPE 251 typedef SQLITE_INT64_TYPE sqlite_int64; 252 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 253#elif defined(_MSC_VER) || defined(__BORLANDC__) 254 typedef __int64 sqlite_int64; 255 typedef unsigned __int64 sqlite_uint64; 256#else 257 typedef long long int sqlite_int64; 258 typedef unsigned long long int sqlite_uint64; 259#endif 260typedef sqlite_int64 sqlite3_int64; 261typedef sqlite_uint64 sqlite3_uint64; 262 263/* 264** If compiling for a processor that lacks floating point support, 265** substitute integer for floating-point. 266*/ 267#ifdef SQLITE_OMIT_FLOATING_POINT 268# define double sqlite3_int64 269#endif 270 271/* 272** CAPI3REF: Closing A Database Connection 273** DESTRUCTOR: sqlite3 274** 275** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 276** for the [sqlite3] object. 277** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 278** the [sqlite3] object is successfully destroyed and all associated 279** resources are deallocated. 280** 281** ^If the database connection is associated with unfinalized prepared 282** statements or unfinished sqlite3_backup objects then sqlite3_close() 283** will leave the database connection open and return [SQLITE_BUSY]. 284** ^If sqlite3_close_v2() is called with unfinalized prepared statements 285** and/or unfinished sqlite3_backups, then the database connection becomes 286** an unusable "zombie" which will automatically be deallocated when the 287** last prepared statement is finalized or the last sqlite3_backup is 288** finished. The sqlite3_close_v2() interface is intended for use with 289** host languages that are garbage collected, and where the order in which 290** destructors are called is arbitrary. 291** 292** Applications should [sqlite3_finalize | finalize] all [prepared statements], 293** [sqlite3_blob_close | close] all [BLOB handles], and 294** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 295** with the [sqlite3] object prior to attempting to close the object. ^If 296** sqlite3_close_v2() is called on a [database connection] that still has 297** outstanding [prepared statements], [BLOB handles], and/or 298** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 299** of resources is deferred until all [prepared statements], [BLOB handles], 300** and [sqlite3_backup] objects are also destroyed. 301** 302** ^If an [sqlite3] object is destroyed while a transaction is open, 303** the transaction is automatically rolled back. 304** 305** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 306** must be either a NULL 307** pointer or an [sqlite3] object pointer obtained 308** from [sqlite3_open()], [sqlite3_open16()], or 309** [sqlite3_open_v2()], and not previously closed. 310** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 311** argument is a harmless no-op. 312*/ 313SQLITE_API int SQLITE_STDCALL sqlite3_close(sqlite3*); 314SQLITE_API int SQLITE_STDCALL sqlite3_close_v2(sqlite3*); 315 316/* 317** The type for a callback function. 318** This is legacy and deprecated. It is included for historical 319** compatibility and is not documented. 320*/ 321typedef int (*sqlite3_callback)(void*,int,char**, char**); 322 323/* 324** CAPI3REF: One-Step Query Execution Interface 325** METHOD: sqlite3 326** 327** The sqlite3_exec() interface is a convenience wrapper around 328** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 329** that allows an application to run multiple statements of SQL 330** without having to use a lot of C code. 331** 332** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 333** semicolon-separate SQL statements passed into its 2nd argument, 334** in the context of the [database connection] passed in as its 1st 335** argument. ^If the callback function of the 3rd argument to 336** sqlite3_exec() is not NULL, then it is invoked for each result row 337** coming out of the evaluated SQL statements. ^The 4th argument to 338** sqlite3_exec() is relayed through to the 1st argument of each 339** callback invocation. ^If the callback pointer to sqlite3_exec() 340** is NULL, then no callback is ever invoked and result rows are 341** ignored. 342** 343** ^If an error occurs while evaluating the SQL statements passed into 344** sqlite3_exec(), then execution of the current statement stops and 345** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 346** is not NULL then any error message is written into memory obtained 347** from [sqlite3_malloc()] and passed back through the 5th parameter. 348** To avoid memory leaks, the application should invoke [sqlite3_free()] 349** on error message strings returned through the 5th parameter of 350** of sqlite3_exec() after the error message string is no longer needed. 351** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 352** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 353** NULL before returning. 354** 355** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 356** routine returns SQLITE_ABORT without invoking the callback again and 357** without running any subsequent SQL statements. 358** 359** ^The 2nd argument to the sqlite3_exec() callback function is the 360** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 361** callback is an array of pointers to strings obtained as if from 362** [sqlite3_column_text()], one for each column. ^If an element of a 363** result row is NULL then the corresponding string pointer for the 364** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 365** sqlite3_exec() callback is an array of pointers to strings where each 366** entry represents the name of corresponding result column as obtained 367** from [sqlite3_column_name()]. 368** 369** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 370** to an empty string, or a pointer that contains only whitespace and/or 371** SQL comments, then no SQL statements are evaluated and the database 372** is not changed. 373** 374** Restrictions: 375** 376** <ul> 377** <li> The application must 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*/ 385SQLITE_API int SQLITE_STDCALL sqlite3_exec( 386 sqlite3*, /* An open database */ 387 const char *sql, /* SQL to be evaluated */ 388 int (*callback)(void*,int,char**,char**), /* Callback function */ 389 void *, /* 1st argument to callback */ 390 char **errmsg /* Error msg written here */ 391); 392 393/* 394** CAPI3REF: Result Codes 395** KEYWORDS: {result code definitions} 396** 397** Many SQLite functions return an integer result code from the set shown 398** here in order to indicate success or failure. 399** 400** New error codes may be added in future versions of SQLite. 401** 402** See also: [extended result code definitions] 403*/ 404#define SQLITE_OK 0 /* Successful result */ 405/* beginning-of-error-codes */ 406#define SQLITE_ERROR 1 /* SQL error or missing database */ 407#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 408#define SQLITE_PERM 3 /* Access permission denied */ 409#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 410#define SQLITE_BUSY 5 /* The database file is locked */ 411#define SQLITE_LOCKED 6 /* A table in the database is locked */ 412#define SQLITE_NOMEM 7 /* A malloc() failed */ 413#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 414#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 415#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 416#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 417#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 418#define SQLITE_FULL 13 /* Insertion failed because database is full */ 419#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 420#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 421#define SQLITE_EMPTY 16 /* Database is empty */ 422#define SQLITE_SCHEMA 17 /* The database schema changed */ 423#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 424#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 425#define SQLITE_MISMATCH 20 /* Data type mismatch */ 426#define SQLITE_MISUSE 21 /* Library used incorrectly */ 427#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 428#define SQLITE_AUTH 23 /* Authorization denied */ 429#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 430#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 431#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 432#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 433#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 434#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 435#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 436/* end-of-error-codes */ 437 438/* 439** CAPI3REF: Extended Result Codes 440** KEYWORDS: {extended result code definitions} 441** 442** In its default configuration, SQLite API routines return one of 30 integer 443** [result codes]. However, experience has shown that many of 444** these result codes are too coarse-grained. They do not provide as 445** much information about problems as programmers might like. In an effort to 446** address this, newer versions of SQLite (version 3.3.8 and later) include 447** support for additional result codes that provide more detailed information 448** about errors. These [extended result codes] are enabled or disabled 449** on a per database connection basis using the 450** [sqlite3_extended_result_codes()] API. Or, the extended code for 451** the most recent error can be obtained using 452** [sqlite3_extended_errcode()]. 453*/ 454#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 455#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 456#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 457#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 458#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 459#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 460#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 461#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 462#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 463#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 464#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 465#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 466#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 467#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 468#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 469#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 470#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 471#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 472#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 473#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 474#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 475#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 476#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 477#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 478#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 479#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 480#define SQLITE_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** <li>[[SQLITE_FCNTL_ZIPVFS]] 967** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 968** VFS should return SQLITE_NOTFOUND for this opcode. 969** 970** <li>[[SQLITE_FCNTL_RBU]] 971** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 972** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 973** this opcode. 974** </ul> 975*/ 976#define SQLITE_FCNTL_LOCKSTATE 1 977#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 978#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 979#define SQLITE_FCNTL_LAST_ERRNO 4 980#define SQLITE_FCNTL_SIZE_HINT 5 981#define SQLITE_FCNTL_CHUNK_SIZE 6 982#define SQLITE_FCNTL_FILE_POINTER 7 983#define SQLITE_FCNTL_SYNC_OMITTED 8 984#define SQLITE_FCNTL_WIN32_AV_RETRY 9 985#define SQLITE_FCNTL_PERSIST_WAL 10 986#define SQLITE_FCNTL_OVERWRITE 11 987#define SQLITE_FCNTL_VFSNAME 12 988#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 989#define SQLITE_FCNTL_PRAGMA 14 990#define SQLITE_FCNTL_BUSYHANDLER 15 991#define SQLITE_FCNTL_TEMPFILENAME 16 992#define SQLITE_FCNTL_MMAP_SIZE 18 993#define SQLITE_FCNTL_TRACE 19 994#define SQLITE_FCNTL_HAS_MOVED 20 995#define SQLITE_FCNTL_SYNC 21 996#define SQLITE_FCNTL_COMMIT_PHASETWO 22 997#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 998#define SQLITE_FCNTL_WAL_BLOCK 24 999#define SQLITE_FCNTL_ZIPVFS 25 1000#define SQLITE_FCNTL_RBU 26 1001 1002/* deprecated names */ 1003#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1004#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1005#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1006 1007 1008/* 1009** CAPI3REF: Mutex Handle 1010** 1011** The mutex module within SQLite defines [sqlite3_mutex] to be an 1012** abstract type for a mutex object. The SQLite core never looks 1013** at the internal representation of an [sqlite3_mutex]. It only 1014** deals with pointers to the [sqlite3_mutex] object. 1015** 1016** Mutexes are created using [sqlite3_mutex_alloc()]. 1017*/ 1018typedef struct sqlite3_mutex sqlite3_mutex; 1019 1020/* 1021** CAPI3REF: OS Interface Object 1022** 1023** An instance of the sqlite3_vfs object defines the interface between 1024** the SQLite core and the underlying operating system. The "vfs" 1025** in the name of the object stands for "virtual file system". See 1026** the [VFS | VFS documentation] for further information. 1027** 1028** The value of the iVersion field is initially 1 but may be larger in 1029** future versions of SQLite. Additional fields may be appended to this 1030** object when the iVersion value is increased. Note that the structure 1031** of the sqlite3_vfs object changes in the transaction between 1032** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1033** modified. 1034** 1035** The szOsFile field is the size of the subclassed [sqlite3_file] 1036** structure used by this VFS. mxPathname is the maximum length of 1037** a pathname in this VFS. 1038** 1039** Registered sqlite3_vfs objects are kept on a linked list formed by 1040** the pNext pointer. The [sqlite3_vfs_register()] 1041** and [sqlite3_vfs_unregister()] interfaces manage this list 1042** in a thread-safe way. The [sqlite3_vfs_find()] interface 1043** searches the list. Neither the application code nor the VFS 1044** implementation should use the pNext pointer. 1045** 1046** The pNext field is the only field in the sqlite3_vfs 1047** structure that SQLite will ever modify. SQLite will only access 1048** or modify this field while holding a particular static mutex. 1049** The application should never modify anything within the sqlite3_vfs 1050** object once the object has been registered. 1051** 1052** The zName field holds the name of the VFS module. The name must 1053** be unique across all VFS modules. 1054** 1055** [[sqlite3_vfs.xOpen]] 1056** ^SQLite guarantees that the zFilename parameter to xOpen 1057** is either a NULL pointer or string obtained 1058** from xFullPathname() with an optional suffix added. 1059** ^If a suffix is added to the zFilename parameter, it will 1060** consist of a single "-" character followed by no more than 1061** 11 alphanumeric and/or "-" characters. 1062** ^SQLite further guarantees that 1063** the string will be valid and unchanged until xClose() is 1064** called. Because of the previous sentence, 1065** the [sqlite3_file] can safely store a pointer to the 1066** filename if it needs to remember the filename for some reason. 1067** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1068** must invent its own temporary name for the file. ^Whenever the 1069** xFilename parameter is NULL it will also be the case that the 1070** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1071** 1072** The flags argument to xOpen() includes all bits set in 1073** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1074** or [sqlite3_open16()] is used, then flags includes at least 1075** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1076** If xOpen() opens a file read-only then it sets *pOutFlags to 1077** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1078** 1079** ^(SQLite will also add one of the following flags to the xOpen() 1080** call, depending on the object being opened: 1081** 1082** <ul> 1083** <li> [SQLITE_OPEN_MAIN_DB] 1084** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1085** <li> [SQLITE_OPEN_TEMP_DB] 1086** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1087** <li> [SQLITE_OPEN_TRANSIENT_DB] 1088** <li> [SQLITE_OPEN_SUBJOURNAL] 1089** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1090** <li> [SQLITE_OPEN_WAL] 1091** </ul>)^ 1092** 1093** The file I/O implementation can use the object type flags to 1094** change the way it deals with files. For example, an application 1095** that does not care about crash recovery or rollback might make 1096** the open of a journal file a no-op. Writes to this journal would 1097** also be no-ops, and any attempt to read the journal would return 1098** SQLITE_IOERR. Or the implementation might recognize that a database 1099** file will be doing page-aligned sector reads and writes in a random 1100** order and set up its I/O subsystem accordingly. 1101** 1102** SQLite might also add one of the following flags to the xOpen method: 1103** 1104** <ul> 1105** <li> [SQLITE_OPEN_DELETEONCLOSE] 1106** <li> [SQLITE_OPEN_EXCLUSIVE] 1107** </ul> 1108** 1109** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1110** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1111** will be set for TEMP databases and their journals, transient 1112** databases, and subjournals. 1113** 1114** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1115** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1116** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1117** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1118** SQLITE_OPEN_CREATE, is used to indicate that file should always 1119** be created, and that it is an error if it already exists. 1120** It is <i>not</i> used to indicate the file should be opened 1121** for exclusive access. 1122** 1123** ^At least szOsFile bytes of memory are allocated by SQLite 1124** to hold the [sqlite3_file] structure passed as the third 1125** argument to xOpen. The xOpen method does not have to 1126** allocate the structure; it should just fill it in. Note that 1127** the xOpen method must set the sqlite3_file.pMethods to either 1128** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1129** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1130** element will be valid after xOpen returns regardless of the success 1131** or failure of the xOpen call. 1132** 1133** [[sqlite3_vfs.xAccess]] 1134** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1135** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1136** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1137** to test whether a file is at least readable. The file can be a 1138** directory. 1139** 1140** ^SQLite will always allocate at least mxPathname+1 bytes for the 1141** output buffer xFullPathname. The exact size of the output buffer 1142** is also passed as a parameter to both methods. If the output buffer 1143** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1144** handled as a fatal error by SQLite, vfs implementations should endeavor 1145** to prevent this by setting mxPathname to a sufficiently large value. 1146** 1147** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1148** interfaces are not strictly a part of the filesystem, but they are 1149** included in the VFS structure for completeness. 1150** The xRandomness() function attempts to return nBytes bytes 1151** of good-quality randomness into zOut. The return value is 1152** the actual number of bytes of randomness obtained. 1153** The xSleep() method causes the calling thread to sleep for at 1154** least the number of microseconds given. ^The xCurrentTime() 1155** method returns a Julian Day Number for the current date and time as 1156** a floating point value. 1157** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1158** Day Number multiplied by 86400000 (the number of milliseconds in 1159** a 24-hour day). 1160** ^SQLite will use the xCurrentTimeInt64() method to get the current 1161** date and time if that method is available (if iVersion is 2 or 1162** greater and the function pointer is not NULL) and will fall back 1163** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1164** 1165** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1166** are not used by the SQLite core. These optional interfaces are provided 1167** by some VFSes to facilitate testing of the VFS code. By overriding 1168** system calls with functions under its control, a test program can 1169** simulate faults and error conditions that would otherwise be difficult 1170** or impossible to induce. The set of system calls that can be overridden 1171** varies from one VFS to another, and from one version of the same VFS to the 1172** next. Applications that use these interfaces must be prepared for any 1173** or all of these interfaces to be NULL or for their behavior to change 1174** from one release to the next. Applications must not attempt to access 1175** any of these methods if the iVersion of the VFS is less than 3. 1176*/ 1177typedef struct sqlite3_vfs sqlite3_vfs; 1178typedef void (*sqlite3_syscall_ptr)(void); 1179struct sqlite3_vfs { 1180 int iVersion; /* Structure version number (currently 3) */ 1181 int szOsFile; /* Size of subclassed sqlite3_file */ 1182 int mxPathname; /* Maximum file pathname length */ 1183 sqlite3_vfs *pNext; /* Next registered VFS */ 1184 const char *zName; /* Name of this virtual file system */ 1185 void *pAppData; /* Pointer to application-specific data */ 1186 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1187 int flags, int *pOutFlags); 1188 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1189 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1190 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1191 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1192 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1193 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1194 void (*xDlClose)(sqlite3_vfs*, void*); 1195 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1196 int (*xSleep)(sqlite3_vfs*, int microseconds); 1197 int (*xCurrentTime)(sqlite3_vfs*, double*); 1198 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1199 /* 1200 ** The methods above are in version 1 of the sqlite_vfs object 1201 ** definition. Those that follow are added in version 2 or later 1202 */ 1203 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1204 /* 1205 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1206 ** Those below are for version 3 and greater. 1207 */ 1208 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1209 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1210 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1211 /* 1212 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1213 ** New fields may be appended in figure versions. The iVersion 1214 ** value will increment whenever this happens. 1215 */ 1216}; 1217 1218/* 1219** CAPI3REF: Flags for the xAccess VFS method 1220** 1221** These integer constants can be used as the third parameter to 1222** the xAccess method of an [sqlite3_vfs] object. They determine 1223** what kind of permissions the xAccess method is looking for. 1224** With SQLITE_ACCESS_EXISTS, the xAccess method 1225** simply checks whether the file exists. 1226** With SQLITE_ACCESS_READWRITE, the xAccess method 1227** checks whether the named directory is both readable and writable 1228** (in other words, if files can be added, removed, and renamed within 1229** the directory). 1230** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1231** [temp_store_directory pragma], though this could change in a future 1232** release of SQLite. 1233** With SQLITE_ACCESS_READ, the xAccess method 1234** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1235** currently unused, though it might be used in a future release of 1236** SQLite. 1237*/ 1238#define SQLITE_ACCESS_EXISTS 0 1239#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1240#define SQLITE_ACCESS_READ 2 /* Unused */ 1241 1242/* 1243** CAPI3REF: Flags for the xShmLock VFS method 1244** 1245** These integer constants define the various locking operations 1246** allowed by the xShmLock method of [sqlite3_io_methods]. The 1247** following are the only legal combinations of flags to the 1248** xShmLock method: 1249** 1250** <ul> 1251** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1252** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1253** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1254** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1255** </ul> 1256** 1257** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1258** was given on the corresponding lock. 1259** 1260** The xShmLock method can transition between unlocked and SHARED or 1261** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1262** and EXCLUSIVE. 1263*/ 1264#define SQLITE_SHM_UNLOCK 1 1265#define SQLITE_SHM_LOCK 2 1266#define SQLITE_SHM_SHARED 4 1267#define SQLITE_SHM_EXCLUSIVE 8 1268 1269/* 1270** CAPI3REF: Maximum xShmLock index 1271** 1272** The xShmLock method on [sqlite3_io_methods] may use values 1273** between 0 and this upper bound as its "offset" argument. 1274** The SQLite core will never attempt to acquire or release a 1275** lock outside of this range 1276*/ 1277#define SQLITE_SHM_NLOCK 8 1278 1279 1280/* 1281** CAPI3REF: Initialize The SQLite Library 1282** 1283** ^The sqlite3_initialize() routine initializes the 1284** SQLite library. ^The sqlite3_shutdown() routine 1285** deallocates any resources that were allocated by sqlite3_initialize(). 1286** These routines are designed to aid in process initialization and 1287** shutdown on embedded systems. Workstation applications using 1288** SQLite normally do not need to invoke either of these routines. 1289** 1290** A call to sqlite3_initialize() is an "effective" call if it is 1291** the first time sqlite3_initialize() is invoked during the lifetime of 1292** the process, or if it is the first time sqlite3_initialize() is invoked 1293** following a call to sqlite3_shutdown(). ^(Only an effective call 1294** of sqlite3_initialize() does any initialization. All other calls 1295** are harmless no-ops.)^ 1296** 1297** A call to sqlite3_shutdown() is an "effective" call if it is the first 1298** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1299** an effective call to sqlite3_shutdown() does any deinitialization. 1300** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1301** 1302** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1303** is not. The sqlite3_shutdown() interface must only be called from a 1304** single thread. All open [database connections] must be closed and all 1305** other SQLite resources must be deallocated prior to invoking 1306** sqlite3_shutdown(). 1307** 1308** Among other things, ^sqlite3_initialize() will invoke 1309** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1310** will invoke sqlite3_os_end(). 1311** 1312** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1313** ^If for some reason, sqlite3_initialize() is unable to initialize 1314** the library (perhaps it is unable to allocate a needed resource such 1315** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1316** 1317** ^The sqlite3_initialize() routine is called internally by many other 1318** SQLite interfaces so that an application usually does not need to 1319** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1320** calls sqlite3_initialize() so the SQLite library will be automatically 1321** initialized when [sqlite3_open()] is called if it has not be initialized 1322** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1323** compile-time option, then the automatic calls to sqlite3_initialize() 1324** are omitted and the application must call sqlite3_initialize() directly 1325** prior to using any other SQLite interface. For maximum portability, 1326** it is recommended that applications always invoke sqlite3_initialize() 1327** directly prior to using any other SQLite interface. Future releases 1328** of SQLite may require this. In other words, the behavior exhibited 1329** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1330** default behavior in some future release of SQLite. 1331** 1332** The sqlite3_os_init() routine does operating-system specific 1333** initialization of the SQLite library. The sqlite3_os_end() 1334** routine undoes the effect of sqlite3_os_init(). Typical tasks 1335** performed by these routines include allocation or deallocation 1336** of static resources, initialization of global variables, 1337** setting up a default [sqlite3_vfs] module, or setting up 1338** a default configuration using [sqlite3_config()]. 1339** 1340** The application should never invoke either sqlite3_os_init() 1341** or sqlite3_os_end() directly. The application should only invoke 1342** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1343** interface is called automatically by sqlite3_initialize() and 1344** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1345** implementations for sqlite3_os_init() and sqlite3_os_end() 1346** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1347** When [custom builds | built for other platforms] 1348** (using the [SQLITE_OS_OTHER=1] compile-time 1349** option) the application must supply a suitable implementation for 1350** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1351** implementation of sqlite3_os_init() or sqlite3_os_end() 1352** must return [SQLITE_OK] on success and some other [error code] upon 1353** failure. 1354*/ 1355SQLITE_API int SQLITE_STDCALL sqlite3_initialize(void); 1356SQLITE_API int SQLITE_STDCALL sqlite3_shutdown(void); 1357SQLITE_API int SQLITE_STDCALL sqlite3_os_init(void); 1358SQLITE_API int SQLITE_STDCALL sqlite3_os_end(void); 1359 1360/* 1361** CAPI3REF: Configuring The SQLite Library 1362** 1363** The sqlite3_config() interface is used to make global configuration 1364** changes to SQLite in order to tune SQLite to the specific needs of 1365** the application. The default configuration is recommended for most 1366** applications and so this routine is usually not necessary. It is 1367** provided to support rare applications with unusual needs. 1368** 1369** The sqlite3_config() interface is not threadsafe. The application 1370** must insure that no other SQLite interfaces are invoked by other 1371** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1372** may only be invoked prior to library initialization using 1373** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1374** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1375** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1376** Note, however, that ^sqlite3_config() can be called as part of the 1377** implementation of an application-defined [sqlite3_os_init()]. 1378** 1379** The first argument to sqlite3_config() is an integer 1380** [configuration option] that determines 1381** what property of SQLite is to be configured. Subsequent arguments 1382** vary depending on the [configuration option] 1383** in the first argument. 1384** 1385** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1386** ^If the option is unknown or SQLite is unable to set the option 1387** then this routine returns a non-zero [error code]. 1388*/ 1389SQLITE_API int SQLITE_CDECL sqlite3_config(int, ...); 1390 1391/* 1392** CAPI3REF: Configure database connections 1393** METHOD: sqlite3 1394** 1395** The sqlite3_db_config() interface is used to make configuration 1396** changes to a [database connection]. The interface is similar to 1397** [sqlite3_config()] except that the changes apply to a single 1398** [database connection] (specified in the first argument). 1399** 1400** The second argument to sqlite3_db_config(D,V,...) is the 1401** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1402** that indicates what aspect of the [database connection] is being configured. 1403** Subsequent arguments vary depending on the configuration verb. 1404** 1405** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1406** the call is considered successful. 1407*/ 1408SQLITE_API int SQLITE_CDECL sqlite3_db_config(sqlite3*, int op, ...); 1409 1410/* 1411** CAPI3REF: Memory Allocation Routines 1412** 1413** An instance of this object defines the interface between SQLite 1414** and low-level memory allocation routines. 1415** 1416** This object is used in only one place in the SQLite interface. 1417** A pointer to an instance of this object is the argument to 1418** [sqlite3_config()] when the configuration option is 1419** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1420** By creating an instance of this object 1421** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1422** during configuration, an application can specify an alternative 1423** memory allocation subsystem for SQLite to use for all of its 1424** dynamic memory needs. 1425** 1426** Note that SQLite comes with several [built-in memory allocators] 1427** that are perfectly adequate for the overwhelming majority of applications 1428** and that this object is only useful to a tiny minority of applications 1429** with specialized memory allocation requirements. This object is 1430** also used during testing of SQLite in order to specify an alternative 1431** memory allocator that simulates memory out-of-memory conditions in 1432** order to verify that SQLite recovers gracefully from such 1433** conditions. 1434** 1435** The xMalloc, xRealloc, and xFree methods must work like the 1436** malloc(), realloc() and free() functions from the standard C library. 1437** ^SQLite guarantees that the second argument to 1438** xRealloc is always a value returned by a prior call to xRoundup. 1439** 1440** xSize should return the allocated size of a memory allocation 1441** previously obtained from xMalloc or xRealloc. The allocated size 1442** is always at least as big as the requested size but may be larger. 1443** 1444** The xRoundup method returns what would be the allocated size of 1445** a memory allocation given a particular requested size. Most memory 1446** allocators round up memory allocations at least to the next multiple 1447** of 8. Some allocators round up to a larger multiple or to a power of 2. 1448** Every memory allocation request coming in through [sqlite3_malloc()] 1449** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1450** that causes the corresponding memory allocation to fail. 1451** 1452** The xInit method initializes the memory allocator. For example, 1453** it might allocate any require mutexes or initialize internal data 1454** structures. The xShutdown method is invoked (indirectly) by 1455** [sqlite3_shutdown()] and should deallocate any resources acquired 1456** by xInit. The pAppData pointer is used as the only parameter to 1457** xInit and xShutdown. 1458** 1459** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1460** the xInit method, so the xInit method need not be threadsafe. The 1461** xShutdown method is only called from [sqlite3_shutdown()] so it does 1462** not need to be threadsafe either. For all other methods, SQLite 1463** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1464** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1465** it is by default) and so the methods are automatically serialized. 1466** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1467** methods must be threadsafe or else make their own arrangements for 1468** serialization. 1469** 1470** SQLite will never invoke xInit() more than once without an intervening 1471** call to xShutdown(). 1472*/ 1473typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1474struct sqlite3_mem_methods { 1475 void *(*xMalloc)(int); /* Memory allocation function */ 1476 void (*xFree)(void*); /* Free a prior allocation */ 1477 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1478 int (*xSize)(void*); /* Return the size of an allocation */ 1479 int (*xRoundup)(int); /* Round up request size to allocation size */ 1480 int (*xInit)(void*); /* Initialize the memory allocator */ 1481 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1482 void *pAppData; /* Argument to xInit() and xShutdown() */ 1483}; 1484 1485/* 1486** CAPI3REF: Configuration Options 1487** KEYWORDS: {configuration option} 1488** 1489** These constants are the available integer configuration options that 1490** can be passed as the first argument to the [sqlite3_config()] interface. 1491** 1492** New configuration options may be added in future releases of SQLite. 1493** Existing configuration options might be discontinued. Applications 1494** should check the return code from [sqlite3_config()] to make sure that 1495** the call worked. The [sqlite3_config()] interface will return a 1496** non-zero [error code] if a discontinued or unsupported configuration option 1497** is invoked. 1498** 1499** <dl> 1500** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1501** <dd>There are no arguments to this option. ^This option sets the 1502** [threading mode] to Single-thread. In other words, it disables 1503** all mutexing and puts SQLite into a mode where it can only be used 1504** by a single thread. ^If SQLite is compiled with 1505** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1506** it is not possible to change the [threading mode] from its default 1507** value of Single-thread and so [sqlite3_config()] will return 1508** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1509** configuration option.</dd> 1510** 1511** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1512** <dd>There are no arguments to this option. ^This option sets the 1513** [threading mode] to Multi-thread. In other words, it disables 1514** mutexing on [database connection] and [prepared statement] objects. 1515** The application is responsible for serializing access to 1516** [database connections] and [prepared statements]. But other mutexes 1517** are enabled so that SQLite will be safe to use in a multi-threaded 1518** environment as long as no two threads attempt to use the same 1519** [database connection] at the same time. ^If SQLite is compiled with 1520** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1521** it is not possible to set the Multi-thread [threading mode] and 1522** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1523** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1524** 1525** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1526** <dd>There are no arguments to this option. ^This option sets the 1527** [threading mode] to Serialized. In other words, this option enables 1528** all mutexes including the recursive 1529** mutexes on [database connection] and [prepared statement] objects. 1530** In this mode (which is the default when SQLite is compiled with 1531** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1532** to [database connections] and [prepared statements] so that the 1533** application is free to use the same [database connection] or the 1534** same [prepared statement] in different threads at the same time. 1535** ^If SQLite is compiled with 1536** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1537** it is not possible to set the Serialized [threading mode] and 1538** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1539** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1540** 1541** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1542** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1543** a pointer to an instance of the [sqlite3_mem_methods] structure. 1544** The argument specifies 1545** alternative low-level memory allocation routines to be used in place of 1546** the memory allocation routines built into SQLite.)^ ^SQLite makes 1547** its own private copy of the content of the [sqlite3_mem_methods] structure 1548** before the [sqlite3_config()] call returns.</dd> 1549** 1550** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1551** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1552** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1553** The [sqlite3_mem_methods] 1554** structure is filled with the currently defined memory allocation routines.)^ 1555** This option can be used to overload the default memory allocation 1556** routines with a wrapper that simulations memory allocation failure or 1557** tracks memory usage, for example. </dd> 1558** 1559** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1560** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1561** interpreted as a boolean, which enables or disables the collection of 1562** memory allocation statistics. ^(When memory allocation statistics are 1563** disabled, the following SQLite interfaces become non-operational: 1564** <ul> 1565** <li> [sqlite3_memory_used()] 1566** <li> [sqlite3_memory_highwater()] 1567** <li> [sqlite3_soft_heap_limit64()] 1568** <li> [sqlite3_status64()] 1569** </ul>)^ 1570** ^Memory allocation statistics are enabled by default unless SQLite is 1571** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1572** allocation statistics are disabled by default. 1573** </dd> 1574** 1575** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1576** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer 1577** that SQLite can use for scratch memory. ^(There are three arguments 1578** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte 1579** aligned memory buffer from which the scratch allocations will be 1580** drawn, the size of each scratch allocation (sz), 1581** and the maximum number of scratch allocations (N).)^ 1582** The first argument must be a pointer to an 8-byte aligned buffer 1583** of at least sz*N bytes of memory. 1584** ^SQLite will not use more than one scratch buffers per thread. 1585** ^SQLite will never request a scratch buffer that is more than 6 1586** times the database page size. 1587** ^If SQLite needs needs additional 1588** scratch memory beyond what is provided by this configuration option, then 1589** [sqlite3_malloc()] will be used to obtain the memory needed.<p> 1590** ^When the application provides any amount of scratch memory using 1591** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large 1592** [sqlite3_malloc|heap allocations]. 1593** This can help [Robson proof|prevent memory allocation failures] due to heap 1594** fragmentation in low-memory embedded systems. 1595** </dd> 1596** 1597** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1598** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer 1599** that SQLite can use for the database page cache with the default page 1600** cache implementation. 1601** This configuration should not be used if an application-define page 1602** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2] 1603** configuration option. 1604** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1605** 8-byte aligned 1606** memory, the size of each page buffer (sz), and the number of pages (N). 1607** The sz argument should be the size of the largest database page 1608** (a power of two between 512 and 65536) plus some extra bytes for each 1609** page header. ^The number of extra bytes needed by the page header 1610** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option 1611** to [sqlite3_config()]. 1612** ^It is harmless, apart from the wasted memory, 1613** for the sz parameter to be larger than necessary. The first 1614** argument should pointer to an 8-byte aligned block of memory that 1615** is at least sz*N bytes of memory, otherwise subsequent behavior is 1616** undefined. 1617** ^SQLite will use the memory provided by the first argument to satisfy its 1618** memory needs for the first N pages that it adds to cache. ^If additional 1619** page cache memory is needed beyond what is provided by this option, then 1620** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd> 1621** 1622** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1623** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1624** that SQLite will use for all of its dynamic memory allocation needs 1625** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and 1626** [SQLITE_CONFIG_PAGECACHE]. 1627** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1628** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1629** [SQLITE_ERROR] if invoked otherwise. 1630** ^There are three arguments to SQLITE_CONFIG_HEAP: 1631** An 8-byte aligned pointer to the memory, 1632** the number of bytes in the memory buffer, and the minimum allocation size. 1633** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1634** to using its default memory allocator (the system malloc() implementation), 1635** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1636** memory pointer is not NULL then the alternative memory 1637** allocator is engaged to handle all of SQLites memory allocation needs. 1638** The first pointer (the memory pointer) must be aligned to an 8-byte 1639** boundary or subsequent behavior of SQLite will be undefined. 1640** The minimum allocation size is capped at 2**12. Reasonable values 1641** for the minimum allocation size are 2**5 through 2**8.</dd> 1642** 1643** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1644** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1645** pointer to an instance of the [sqlite3_mutex_methods] structure. 1646** The argument specifies alternative low-level mutex routines to be used 1647** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1648** the content of the [sqlite3_mutex_methods] structure before the call to 1649** [sqlite3_config()] returns. ^If SQLite is compiled with 1650** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1651** the entire mutexing subsystem is omitted from the build and hence calls to 1652** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1653** return [SQLITE_ERROR].</dd> 1654** 1655** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1656** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1657** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1658** [sqlite3_mutex_methods] 1659** structure is filled with the currently defined mutex routines.)^ 1660** This option can be used to overload the default mutex allocation 1661** routines with a wrapper used to track mutex usage for performance 1662** profiling or testing, for example. ^If SQLite is compiled with 1663** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1664** the entire mutexing subsystem is omitted from the build and hence calls to 1665** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1666** return [SQLITE_ERROR].</dd> 1667** 1668** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1669** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1670** the default size of lookaside memory on each [database connection]. 1671** The first argument is the 1672** size of each lookaside buffer slot and the second is the number of 1673** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1674** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1675** option to [sqlite3_db_config()] can be used to change the lookaside 1676** configuration on individual connections.)^ </dd> 1677** 1678** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1679** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1680** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1681** the interface to a custom page cache implementation.)^ 1682** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1683** 1684** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1685** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1686** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1687** the current page cache implementation into that object.)^ </dd> 1688** 1689** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1690** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1691** global [error log]. 1692** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1693** function with a call signature of void(*)(void*,int,const char*), 1694** and a pointer to void. ^If the function pointer is not NULL, it is 1695** invoked by [sqlite3_log()] to process each logging event. ^If the 1696** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1697** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1698** passed through as the first parameter to the application-defined logger 1699** function whenever that function is invoked. ^The second parameter to 1700** the logger function is a copy of the first parameter to the corresponding 1701** [sqlite3_log()] call and is intended to be a [result code] or an 1702** [extended result code]. ^The third parameter passed to the logger is 1703** log message after formatting via [sqlite3_snprintf()]. 1704** The SQLite logging interface is not reentrant; the logger function 1705** supplied by the application must not invoke any SQLite interface. 1706** In a multi-threaded application, the application-defined logger 1707** function must be threadsafe. </dd> 1708** 1709** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1710** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1711** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1712** then URI handling is globally disabled.)^ ^If URI handling is globally 1713** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1714** [sqlite3_open16()] or 1715** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1716** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1717** connection is opened. ^If it is globally disabled, filenames are 1718** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1719** database connection is opened. ^(By default, URI handling is globally 1720** disabled. The default value may be changed by compiling with the 1721** [SQLITE_USE_URI] symbol defined.)^ 1722** 1723** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1724** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1725** argument which is interpreted as a boolean in order to enable or disable 1726** the use of covering indices for full table scans in the query optimizer. 1727** ^The default setting is determined 1728** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1729** if that compile-time option is omitted. 1730** The ability to disable the use of covering indices for full table scans 1731** is because some incorrectly coded legacy applications might malfunction 1732** when the optimization is enabled. Providing the ability to 1733** disable the optimization allows the older, buggy application code to work 1734** without change even with newer versions of SQLite. 1735** 1736** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1737** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1738** <dd> These options are obsolete and should not be used by new code. 1739** They are retained for backwards compatibility but are now no-ops. 1740** </dd> 1741** 1742** [[SQLITE_CONFIG_SQLLOG]] 1743** <dt>SQLITE_CONFIG_SQLLOG 1744** <dd>This option is only available if sqlite is compiled with the 1745** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1746** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1747** The second should be of type (void*). The callback is invoked by the library 1748** in three separate circumstances, identified by the value passed as the 1749** fourth parameter. If the fourth parameter is 0, then the database connection 1750** passed as the second argument has just been opened. The third argument 1751** points to a buffer containing the name of the main database file. If the 1752** fourth parameter is 1, then the SQL statement that the third parameter 1753** points to has just been executed. Or, if the fourth parameter is 2, then 1754** the connection being passed as the second parameter is being closed. The 1755** third parameter is passed NULL In this case. An example of using this 1756** configuration option can be seen in the "test_sqllog.c" source file in 1757** the canonical SQLite source tree.</dd> 1758** 1759** [[SQLITE_CONFIG_MMAP_SIZE]] 1760** <dt>SQLITE_CONFIG_MMAP_SIZE 1761** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1762** that are the default mmap size limit (the default setting for 1763** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1764** ^The default setting can be overridden by each database connection using 1765** either the [PRAGMA mmap_size] command, or by using the 1766** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1767** will be silently truncated if necessary so that it does not exceed the 1768** compile-time maximum mmap size set by the 1769** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1770** ^If either argument to this option is negative, then that argument is 1771** changed to its compile-time default. 1772** 1773** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1774** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1775** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1776** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1777** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1778** that specifies the maximum size of the created heap. 1779** 1780** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1781** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1782** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1783** is a pointer to an integer and writes into that integer the number of extra 1784** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1785** The amount of extra space required can change depending on the compiler, 1786** target platform, and SQLite version. 1787** 1788** [[SQLITE_CONFIG_PMASZ]] 1789** <dt>SQLITE_CONFIG_PMASZ 1790** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1791** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1792** sorter to that integer. The default minimum PMA Size is set by the 1793** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1794** to help with sort operations when multithreaded sorting 1795** is enabled (using the [PRAGMA threads] command) and the amount of content 1796** to be sorted exceeds the page size times the minimum of the 1797** [PRAGMA cache_size] setting and this value. 1798** </dl> 1799*/ 1800#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1801#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1802#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1803#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1804#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1805#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1806#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1807#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1808#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1809#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1810#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1811/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1812#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1813#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1814#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1815#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1816#define SQLITE_CONFIG_URI 17 /* int */ 1817#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1818#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1819#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1820#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1821#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1822#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1823#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1824#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1825 1826/* 1827** CAPI3REF: Database Connection Configuration Options 1828** 1829** These constants are the available integer configuration options that 1830** can be passed as the second argument to the [sqlite3_db_config()] interface. 1831** 1832** New configuration options may be added in future releases of SQLite. 1833** Existing configuration options might be discontinued. Applications 1834** should check the return code from [sqlite3_db_config()] to make sure that 1835** the call worked. ^The [sqlite3_db_config()] interface will return a 1836** non-zero [error code] if a discontinued or unsupported configuration option 1837** is invoked. 1838** 1839** <dl> 1840** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1841** <dd> ^This option takes three additional arguments that determine the 1842** [lookaside memory allocator] configuration for the [database connection]. 1843** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1844** pointer to a memory buffer to use for lookaside memory. 1845** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1846** may be NULL in which case SQLite will allocate the 1847** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1848** size of each lookaside buffer slot. ^The third argument is the number of 1849** slots. The size of the buffer in the first argument must be greater than 1850** or equal to the product of the second and third arguments. The buffer 1851** must be aligned to an 8-byte boundary. ^If the second argument to 1852** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1853** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1854** configuration for a database connection can only be changed when that 1855** connection is not currently using lookaside memory, or in other words 1856** when the "current value" returned by 1857** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1858** Any attempt to change the lookaside memory configuration when lookaside 1859** memory is in use leaves the configuration unchanged and returns 1860** [SQLITE_BUSY].)^</dd> 1861** 1862** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1863** <dd> ^This option is used to enable or disable the enforcement of 1864** [foreign key constraints]. There should be two additional arguments. 1865** The first argument is an integer which is 0 to disable FK enforcement, 1866** positive to enable FK enforcement or negative to leave FK enforcement 1867** unchanged. The second parameter is a pointer to an integer into which 1868** is written 0 or 1 to indicate whether FK enforcement is off or on 1869** following this call. The second parameter may be a NULL pointer, in 1870** which case the FK enforcement setting is not reported back. </dd> 1871** 1872** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1873** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1874** There should be two additional arguments. 1875** The first argument is an integer which is 0 to disable triggers, 1876** positive to enable triggers or negative to leave the setting unchanged. 1877** The second parameter is a pointer to an integer into which 1878** is written 0 or 1 to indicate whether triggers are disabled or enabled 1879** following this call. The second parameter may be a NULL pointer, in 1880** which case the trigger setting is not reported back. </dd> 1881** 1882** </dl> 1883*/ 1884#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1885#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1886#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1887 1888 1889/* 1890** CAPI3REF: Enable Or Disable Extended Result Codes 1891** METHOD: sqlite3 1892** 1893** ^The sqlite3_extended_result_codes() routine enables or disables the 1894** [extended result codes] feature of SQLite. ^The extended result 1895** codes are disabled by default for historical compatibility. 1896*/ 1897SQLITE_API int SQLITE_STDCALL sqlite3_extended_result_codes(sqlite3*, int onoff); 1898 1899/* 1900** CAPI3REF: Last Insert Rowid 1901** METHOD: sqlite3 1902** 1903** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 1904** has a unique 64-bit signed 1905** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1906** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1907** names are not also used by explicitly declared columns. ^If 1908** the table has a column of type [INTEGER PRIMARY KEY] then that column 1909** is another alias for the rowid. 1910** 1911** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the 1912** most recent successful [INSERT] into a rowid table or [virtual table] 1913** on database connection D. 1914** ^Inserts into [WITHOUT ROWID] tables are not recorded. 1915** ^If no successful [INSERT]s into rowid tables 1916** have ever occurred on the database connection D, 1917** then sqlite3_last_insert_rowid(D) returns zero. 1918** 1919** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1920** method, then this routine will return the [rowid] of the inserted 1921** row as long as the trigger or virtual table method is running. 1922** But once the trigger or virtual table method ends, the value returned 1923** by this routine reverts to what it was before the trigger or virtual 1924** table method began.)^ 1925** 1926** ^An [INSERT] that fails due to a constraint violation is not a 1927** successful [INSERT] and does not change the value returned by this 1928** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1929** and INSERT OR ABORT make no changes to the return value of this 1930** routine when their insertion fails. ^(When INSERT OR REPLACE 1931** encounters a constraint violation, it does not fail. The 1932** INSERT continues to completion after deleting rows that caused 1933** the constraint problem so INSERT OR REPLACE will always change 1934** the return value of this interface.)^ 1935** 1936** ^For the purposes of this routine, an [INSERT] is considered to 1937** be successful even if it is subsequently rolled back. 1938** 1939** This function is accessible to SQL statements via the 1940** [last_insert_rowid() SQL function]. 1941** 1942** If a separate thread performs a new [INSERT] on the same 1943** database connection while the [sqlite3_last_insert_rowid()] 1944** function is running and thus changes the last insert [rowid], 1945** then the value returned by [sqlite3_last_insert_rowid()] is 1946** unpredictable and might not equal either the old or the new 1947** last insert [rowid]. 1948*/ 1949SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_last_insert_rowid(sqlite3*); 1950 1951/* 1952** CAPI3REF: Count The Number Of Rows Modified 1953** METHOD: sqlite3 1954** 1955** ^This function returns the number of rows modified, inserted or 1956** deleted by the most recently completed INSERT, UPDATE or DELETE 1957** statement on the database connection specified by the only parameter. 1958** ^Executing any other type of SQL statement does not modify the value 1959** returned by this function. 1960** 1961** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 1962** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 1963** [foreign key actions] or [REPLACE] constraint resolution are not counted. 1964** 1965** Changes to a view that are intercepted by 1966** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 1967** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 1968** DELETE statement run on a view is always zero. Only changes made to real 1969** tables are counted. 1970** 1971** Things are more complicated if the sqlite3_changes() function is 1972** executed while a trigger program is running. This may happen if the 1973** program uses the [changes() SQL function], or if some other callback 1974** function invokes sqlite3_changes() directly. Essentially: 1975** 1976** <ul> 1977** <li> ^(Before entering a trigger program the value returned by 1978** sqlite3_changes() function is saved. After the trigger program 1979** has finished, the original value is restored.)^ 1980** 1981** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 1982** statement sets the value returned by sqlite3_changes() 1983** upon completion as normal. Of course, this value will not include 1984** any changes performed by sub-triggers, as the sqlite3_changes() 1985** value will be saved and restored after each sub-trigger has run.)^ 1986** </ul> 1987** 1988** ^This means that if the changes() SQL function (or similar) is used 1989** by the first INSERT, UPDATE or DELETE statement within a trigger, it 1990** returns the value as set when the calling statement began executing. 1991** ^If it is used by the second or subsequent such statement within a trigger 1992** program, the value returned reflects the number of rows modified by the 1993** previous INSERT, UPDATE or DELETE statement within the same trigger. 1994** 1995** See also the [sqlite3_total_changes()] interface, the 1996** [count_changes pragma], and the [changes() SQL function]. 1997** 1998** If a separate thread makes changes on the same database connection 1999** while [sqlite3_changes()] is running then the value returned 2000** is unpredictable and not meaningful. 2001*/ 2002SQLITE_API int SQLITE_STDCALL sqlite3_changes(sqlite3*); 2003 2004/* 2005** CAPI3REF: Total Number Of Rows Modified 2006** METHOD: sqlite3 2007** 2008** ^This function returns the total number of rows inserted, modified or 2009** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2010** since the database connection was opened, including those executed as 2011** part of trigger programs. ^Executing any other type of SQL statement 2012** does not affect the value returned by sqlite3_total_changes(). 2013** 2014** ^Changes made as part of [foreign key actions] are included in the 2015** count, but those made as part of REPLACE constraint resolution are 2016** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2017** are not counted. 2018** 2019** See also the [sqlite3_changes()] interface, the 2020** [count_changes pragma], and the [total_changes() SQL function]. 2021** 2022** If a separate thread makes changes on the same database connection 2023** while [sqlite3_total_changes()] is running then the value 2024** returned is unpredictable and not meaningful. 2025*/ 2026SQLITE_API int SQLITE_STDCALL sqlite3_total_changes(sqlite3*); 2027 2028/* 2029** CAPI3REF: Interrupt A Long-Running Query 2030** METHOD: sqlite3 2031** 2032** ^This function causes any pending database operation to abort and 2033** return at its earliest opportunity. This routine is typically 2034** called in response to a user action such as pressing "Cancel" 2035** or Ctrl-C where the user wants a long query operation to halt 2036** immediately. 2037** 2038** ^It is safe to call this routine from a thread different from the 2039** thread that is currently running the database operation. But it 2040** is not safe to call this routine with a [database connection] that 2041** is closed or might close before sqlite3_interrupt() returns. 2042** 2043** ^If an SQL operation is very nearly finished at the time when 2044** sqlite3_interrupt() is called, then it might not have an opportunity 2045** to be interrupted and might continue to completion. 2046** 2047** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2048** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2049** that is inside an explicit transaction, then the entire transaction 2050** will be rolled back automatically. 2051** 2052** ^The sqlite3_interrupt(D) call is in effect until all currently running 2053** SQL statements on [database connection] D complete. ^Any new SQL statements 2054** that are started after the sqlite3_interrupt() call and before the 2055** running statements reaches zero are interrupted as if they had been 2056** running prior to the sqlite3_interrupt() call. ^New SQL statements 2057** that are started after the running statement count reaches zero are 2058** not effected by the sqlite3_interrupt(). 2059** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2060** SQL statements is a no-op and has no effect on SQL statements 2061** that are started after the sqlite3_interrupt() call returns. 2062** 2063** If the database connection closes while [sqlite3_interrupt()] 2064** is running then bad things will likely happen. 2065*/ 2066SQLITE_API void SQLITE_STDCALL sqlite3_interrupt(sqlite3*); 2067 2068/* 2069** CAPI3REF: Determine If An SQL Statement Is Complete 2070** 2071** These routines are useful during command-line input to determine if the 2072** currently entered text seems to form a complete SQL statement or 2073** if additional input is needed before sending the text into 2074** SQLite for parsing. ^These routines return 1 if the input string 2075** appears to be a complete SQL statement. ^A statement is judged to be 2076** complete if it ends with a semicolon token and is not a prefix of a 2077** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2078** string literals or quoted identifier names or comments are not 2079** independent tokens (they are part of the token in which they are 2080** embedded) and thus do not count as a statement terminator. ^Whitespace 2081** and comments that follow the final semicolon are ignored. 2082** 2083** ^These routines return 0 if the statement is incomplete. ^If a 2084** memory allocation fails, then SQLITE_NOMEM is returned. 2085** 2086** ^These routines do not parse the SQL statements thus 2087** will not detect syntactically incorrect SQL. 2088** 2089** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2090** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2091** automatically by sqlite3_complete16(). If that initialization fails, 2092** then the return value from sqlite3_complete16() will be non-zero 2093** regardless of whether or not the input SQL is complete.)^ 2094** 2095** The input to [sqlite3_complete()] must be a zero-terminated 2096** UTF-8 string. 2097** 2098** The input to [sqlite3_complete16()] must be a zero-terminated 2099** UTF-16 string in native byte order. 2100*/ 2101SQLITE_API int SQLITE_STDCALL sqlite3_complete(const char *sql); 2102SQLITE_API int SQLITE_STDCALL sqlite3_complete16(const void *sql); 2103 2104/* 2105** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2106** KEYWORDS: {busy-handler callback} {busy handler} 2107** METHOD: sqlite3 2108** 2109** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2110** that might be invoked with argument P whenever 2111** an attempt is made to access a database table associated with 2112** [database connection] D when another thread 2113** or process has the table locked. 2114** The sqlite3_busy_handler() interface is used to implement 2115** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2116** 2117** ^If the busy callback is NULL, then [SQLITE_BUSY] 2118** is returned immediately upon encountering the lock. ^If the busy callback 2119** is not NULL, then the callback might be invoked with two arguments. 2120** 2121** ^The first argument to the busy handler is a copy of the void* pointer which 2122** is the third argument to sqlite3_busy_handler(). ^The second argument to 2123** the busy handler callback is the number of times that the busy handler has 2124** been invoked previously for the same locking event. ^If the 2125** busy callback returns 0, then no additional attempts are made to 2126** access the database and [SQLITE_BUSY] is returned 2127** to the application. 2128** ^If the callback returns non-zero, then another attempt 2129** is made to access the database and the cycle repeats. 2130** 2131** The presence of a busy handler does not guarantee that it will be invoked 2132** when there is lock contention. ^If SQLite determines that invoking the busy 2133** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2134** to the application instead of invoking the 2135** busy handler. 2136** Consider a scenario where one process is holding a read lock that 2137** it is trying to promote to a reserved lock and 2138** a second process is holding a reserved lock that it is trying 2139** to promote to an exclusive lock. The first process cannot proceed 2140** because it is blocked by the second and the second process cannot 2141** proceed because it is blocked by the first. If both processes 2142** invoke the busy handlers, neither will make any progress. Therefore, 2143** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2144** will induce the first process to release its read lock and allow 2145** the second process to proceed. 2146** 2147** ^The default busy callback is NULL. 2148** 2149** ^(There can only be a single busy handler defined for each 2150** [database connection]. Setting a new busy handler clears any 2151** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2152** or evaluating [PRAGMA busy_timeout=N] will change the 2153** busy handler and thus clear any previously set busy handler. 2154** 2155** The busy callback should not take any actions which modify the 2156** database connection that invoked the busy handler. In other words, 2157** the busy handler is not reentrant. Any such actions 2158** result in undefined behavior. 2159** 2160** A busy handler must not close the database connection 2161** or [prepared statement] that invoked the busy handler. 2162*/ 2163SQLITE_API int SQLITE_STDCALL sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2164 2165/* 2166** CAPI3REF: Set A Busy Timeout 2167** METHOD: sqlite3 2168** 2169** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2170** for a specified amount of time when a table is locked. ^The handler 2171** will sleep multiple times until at least "ms" milliseconds of sleeping 2172** have accumulated. ^After at least "ms" milliseconds of sleeping, 2173** the handler returns 0 which causes [sqlite3_step()] to return 2174** [SQLITE_BUSY]. 2175** 2176** ^Calling this routine with an argument less than or equal to zero 2177** turns off all busy handlers. 2178** 2179** ^(There can only be a single busy handler for a particular 2180** [database connection] at any given moment. If another busy handler 2181** was defined (using [sqlite3_busy_handler()]) prior to calling 2182** this routine, that other busy handler is cleared.)^ 2183** 2184** See also: [PRAGMA busy_timeout] 2185*/ 2186SQLITE_API int SQLITE_STDCALL sqlite3_busy_timeout(sqlite3*, int ms); 2187 2188/* 2189** CAPI3REF: Convenience Routines For Running Queries 2190** METHOD: sqlite3 2191** 2192** This is a legacy interface that is preserved for backwards compatibility. 2193** Use of this interface is not recommended. 2194** 2195** Definition: A <b>result table</b> is memory data structure created by the 2196** [sqlite3_get_table()] interface. A result table records the 2197** complete query results from one or more queries. 2198** 2199** The table conceptually has a number of rows and columns. But 2200** these numbers are not part of the result table itself. These 2201** numbers are obtained separately. Let N be the number of rows 2202** and M be the number of columns. 2203** 2204** A result table is an array of pointers to zero-terminated UTF-8 strings. 2205** There are (N+1)*M elements in the array. The first M pointers point 2206** to zero-terminated strings that contain the names of the columns. 2207** The remaining entries all point to query results. NULL values result 2208** in NULL pointers. All other values are in their UTF-8 zero-terminated 2209** string representation as returned by [sqlite3_column_text()]. 2210** 2211** A result table might consist of one or more memory allocations. 2212** It is not safe to pass a result table directly to [sqlite3_free()]. 2213** A result table should be deallocated using [sqlite3_free_table()]. 2214** 2215** ^(As an example of the result table format, suppose a query result 2216** is as follows: 2217** 2218** <blockquote><pre> 2219** Name | Age 2220** ----------------------- 2221** Alice | 43 2222** Bob | 28 2223** Cindy | 21 2224** </pre></blockquote> 2225** 2226** There are two column (M==2) and three rows (N==3). Thus the 2227** result table has 8 entries. Suppose the result table is stored 2228** in an array names azResult. Then azResult holds this content: 2229** 2230** <blockquote><pre> 2231** azResult[0] = "Name"; 2232** azResult[1] = "Age"; 2233** azResult[2] = "Alice"; 2234** azResult[3] = "43"; 2235** azResult[4] = "Bob"; 2236** azResult[5] = "28"; 2237** azResult[6] = "Cindy"; 2238** azResult[7] = "21"; 2239** </pre></blockquote>)^ 2240** 2241** ^The sqlite3_get_table() function evaluates one or more 2242** semicolon-separated SQL statements in the zero-terminated UTF-8 2243** string of its 2nd parameter and returns a result table to the 2244** pointer given in its 3rd parameter. 2245** 2246** After the application has finished with the result from sqlite3_get_table(), 2247** it must pass the result table pointer to sqlite3_free_table() in order to 2248** release the memory that was malloced. Because of the way the 2249** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2250** function must not try to call [sqlite3_free()] directly. Only 2251** [sqlite3_free_table()] is able to release the memory properly and safely. 2252** 2253** The sqlite3_get_table() interface is implemented as a wrapper around 2254** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2255** to any internal data structures of SQLite. It uses only the public 2256** interface defined here. As a consequence, errors that occur in the 2257** wrapper layer outside of the internal [sqlite3_exec()] call are not 2258** reflected in subsequent calls to [sqlite3_errcode()] or 2259** [sqlite3_errmsg()]. 2260*/ 2261SQLITE_API int SQLITE_STDCALL sqlite3_get_table( 2262 sqlite3 *db, /* An open database */ 2263 const char *zSql, /* SQL to be evaluated */ 2264 char ***pazResult, /* Results of the query */ 2265 int *pnRow, /* Number of result rows written here */ 2266 int *pnColumn, /* Number of result columns written here */ 2267 char **pzErrmsg /* Error msg written here */ 2268); 2269SQLITE_API void SQLITE_STDCALL sqlite3_free_table(char **result); 2270 2271/* 2272** CAPI3REF: Formatted String Printing Functions 2273** 2274** These routines are work-alikes of the "printf()" family of functions 2275** from the standard C library. 2276** These routines understand most of the common K&R formatting options, 2277** plus some additional non-standard formats, detailed below. 2278** Note that some of the more obscure formatting options from recent 2279** C-library standards are omitted from this implementation. 2280** 2281** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2282** results into memory obtained from [sqlite3_malloc()]. 2283** The strings returned by these two routines should be 2284** released by [sqlite3_free()]. ^Both routines return a 2285** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2286** memory to hold the resulting string. 2287** 2288** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2289** the standard C library. The result is written into the 2290** buffer supplied as the second parameter whose size is given by 2291** the first parameter. Note that the order of the 2292** first two parameters is reversed from snprintf().)^ This is an 2293** historical accident that cannot be fixed without breaking 2294** backwards compatibility. ^(Note also that sqlite3_snprintf() 2295** returns a pointer to its buffer instead of the number of 2296** characters actually written into the buffer.)^ We admit that 2297** the number of characters written would be a more useful return 2298** value but we cannot change the implementation of sqlite3_snprintf() 2299** now without breaking compatibility. 2300** 2301** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2302** guarantees that the buffer is always zero-terminated. ^The first 2303** parameter "n" is the total size of the buffer, including space for 2304** the zero terminator. So the longest string that can be completely 2305** written will be n-1 characters. 2306** 2307** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2308** 2309** These routines all implement some additional formatting 2310** options that are useful for constructing SQL statements. 2311** All of the usual printf() formatting options apply. In addition, there 2312** is are "%q", "%Q", "%w" and "%z" options. 2313** 2314** ^(The %q option works like %s in that it substitutes a nul-terminated 2315** string from the argument list. But %q also doubles every '\'' character. 2316** %q is designed for use inside a string literal.)^ By doubling each '\'' 2317** character it escapes that character and allows it to be inserted into 2318** the string. 2319** 2320** For example, assume the string variable zText contains text as follows: 2321** 2322** <blockquote><pre> 2323** char *zText = "It's a happy day!"; 2324** </pre></blockquote> 2325** 2326** One can use this text in an SQL statement as follows: 2327** 2328** <blockquote><pre> 2329** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2330** sqlite3_exec(db, zSQL, 0, 0, 0); 2331** sqlite3_free(zSQL); 2332** </pre></blockquote> 2333** 2334** Because the %q format string is used, the '\'' character in zText 2335** is escaped and the SQL generated is as follows: 2336** 2337** <blockquote><pre> 2338** INSERT INTO table1 VALUES('It''s a happy day!') 2339** </pre></blockquote> 2340** 2341** This is correct. Had we used %s instead of %q, the generated SQL 2342** would have looked like this: 2343** 2344** <blockquote><pre> 2345** INSERT INTO table1 VALUES('It's a happy day!'); 2346** </pre></blockquote> 2347** 2348** This second example is an SQL syntax error. As a general rule you should 2349** always use %q instead of %s when inserting text into a string literal. 2350** 2351** ^(The %Q option works like %q except it also adds single quotes around 2352** the outside of the total string. Additionally, if the parameter in the 2353** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2354** single quotes).)^ So, for example, one could say: 2355** 2356** <blockquote><pre> 2357** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2358** sqlite3_exec(db, zSQL, 0, 0, 0); 2359** sqlite3_free(zSQL); 2360** </pre></blockquote> 2361** 2362** The code above will render a correct SQL statement in the zSQL 2363** variable even if the zText variable is a NULL pointer. 2364** 2365** ^(The "%w" formatting option is like "%q" except that it expects to 2366** be contained within double-quotes instead of single quotes, and it 2367** escapes the double-quote character instead of the single-quote 2368** character.)^ The "%w" formatting option is intended for safely inserting 2369** table and column names into a constructed SQL statement. 2370** 2371** ^(The "%z" formatting option works like "%s" but with the 2372** addition that after the string has been read and copied into 2373** the result, [sqlite3_free()] is called on the input string.)^ 2374*/ 2375SQLITE_API char *SQLITE_CDECL sqlite3_mprintf(const char*,...); 2376SQLITE_API char *SQLITE_STDCALL sqlite3_vmprintf(const char*, va_list); 2377SQLITE_API char *SQLITE_CDECL sqlite3_snprintf(int,char*,const char*, ...); 2378SQLITE_API char *SQLITE_STDCALL sqlite3_vsnprintf(int,char*,const char*, va_list); 2379 2380/* 2381** CAPI3REF: Memory Allocation Subsystem 2382** 2383** The SQLite core uses these three routines for all of its own 2384** internal memory allocation needs. "Core" in the previous sentence 2385** does not include operating-system specific VFS implementation. The 2386** Windows VFS uses native malloc() and free() for some operations. 2387** 2388** ^The sqlite3_malloc() routine returns a pointer to a block 2389** of memory at least N bytes in length, where N is the parameter. 2390** ^If sqlite3_malloc() is unable to obtain sufficient free 2391** memory, it returns a NULL pointer. ^If the parameter N to 2392** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2393** a NULL pointer. 2394** 2395** ^The sqlite3_malloc64(N) routine works just like 2396** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2397** of a signed 32-bit integer. 2398** 2399** ^Calling sqlite3_free() with a pointer previously returned 2400** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2401** that it might be reused. ^The sqlite3_free() routine is 2402** a no-op if is called with a NULL pointer. Passing a NULL pointer 2403** to sqlite3_free() is harmless. After being freed, memory 2404** should neither be read nor written. Even reading previously freed 2405** memory might result in a segmentation fault or other severe error. 2406** Memory corruption, a segmentation fault, or other severe error 2407** might result if sqlite3_free() is called with a non-NULL pointer that 2408** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2409** 2410** ^The sqlite3_realloc(X,N) interface attempts to resize a 2411** prior memory allocation X to be at least N bytes. 2412** ^If the X parameter to sqlite3_realloc(X,N) 2413** is a NULL pointer then its behavior is identical to calling 2414** sqlite3_malloc(N). 2415** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2416** negative then the behavior is exactly the same as calling 2417** sqlite3_free(X). 2418** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2419** of at least N bytes in size or NULL if insufficient memory is available. 2420** ^If M is the size of the prior allocation, then min(N,M) bytes 2421** of the prior allocation are copied into the beginning of buffer returned 2422** by sqlite3_realloc(X,N) and the prior allocation is freed. 2423** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2424** prior allocation is not freed. 2425** 2426** ^The sqlite3_realloc64(X,N) interfaces works the same as 2427** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2428** of a 32-bit signed integer. 2429** 2430** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2431** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2432** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2433** ^The value returned by sqlite3_msize(X) might be larger than the number 2434** of bytes requested when X was allocated. ^If X is a NULL pointer then 2435** sqlite3_msize(X) returns zero. If X points to something that is not 2436** the beginning of memory allocation, or if it points to a formerly 2437** valid memory allocation that has now been freed, then the behavior 2438** of sqlite3_msize(X) is undefined and possibly harmful. 2439** 2440** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2441** sqlite3_malloc64(), and sqlite3_realloc64() 2442** is always aligned to at least an 8 byte boundary, or to a 2443** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2444** option is used. 2445** 2446** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2447** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2448** implementation of these routines to be omitted. That capability 2449** is no longer provided. Only built-in memory allocators can be used. 2450** 2451** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2452** the system malloc() and free() directly when converting 2453** filenames between the UTF-8 encoding used by SQLite 2454** and whatever filename encoding is used by the particular Windows 2455** installation. Memory allocation errors were detected, but 2456** they were reported back as [SQLITE_CANTOPEN] or 2457** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2458** 2459** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2460** must be either NULL or else pointers obtained from a prior 2461** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2462** not yet been released. 2463** 2464** The application must not read or write any part of 2465** a block of memory after it has been released using 2466** [sqlite3_free()] or [sqlite3_realloc()]. 2467*/ 2468SQLITE_API void *SQLITE_STDCALL sqlite3_malloc(int); 2469SQLITE_API void *SQLITE_STDCALL sqlite3_malloc64(sqlite3_uint64); 2470SQLITE_API void *SQLITE_STDCALL sqlite3_realloc(void*, int); 2471SQLITE_API void *SQLITE_STDCALL sqlite3_realloc64(void*, sqlite3_uint64); 2472SQLITE_API void SQLITE_STDCALL sqlite3_free(void*); 2473SQLITE_API sqlite3_uint64 SQLITE_STDCALL sqlite3_msize(void*); 2474 2475/* 2476** CAPI3REF: Memory Allocator Statistics 2477** 2478** SQLite provides these two interfaces for reporting on the status 2479** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2480** routines, which form the built-in memory allocation subsystem. 2481** 2482** ^The [sqlite3_memory_used()] routine returns the number of bytes 2483** of memory currently outstanding (malloced but not freed). 2484** ^The [sqlite3_memory_highwater()] routine returns the maximum 2485** value of [sqlite3_memory_used()] since the high-water mark 2486** was last reset. ^The values returned by [sqlite3_memory_used()] and 2487** [sqlite3_memory_highwater()] include any overhead 2488** added by SQLite in its implementation of [sqlite3_malloc()], 2489** but not overhead added by the any underlying system library 2490** routines that [sqlite3_malloc()] may call. 2491** 2492** ^The memory high-water mark is reset to the current value of 2493** [sqlite3_memory_used()] if and only if the parameter to 2494** [sqlite3_memory_highwater()] is true. ^The value returned 2495** by [sqlite3_memory_highwater(1)] is the high-water mark 2496** prior to the reset. 2497*/ 2498SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_used(void); 2499SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_highwater(int resetFlag); 2500 2501/* 2502** CAPI3REF: Pseudo-Random Number Generator 2503** 2504** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2505** select random [ROWID | ROWIDs] when inserting new records into a table that 2506** already uses the largest possible [ROWID]. The PRNG is also used for 2507** the build-in random() and randomblob() SQL functions. This interface allows 2508** applications to access the same PRNG for other purposes. 2509** 2510** ^A call to this routine stores N bytes of randomness into buffer P. 2511** ^The P parameter can be a NULL pointer. 2512** 2513** ^If this routine has not been previously called or if the previous 2514** call had N less than one or a NULL pointer for P, then the PRNG is 2515** seeded using randomness obtained from the xRandomness method of 2516** the default [sqlite3_vfs] object. 2517** ^If the previous call to this routine had an N of 1 or more and a 2518** non-NULL P then the pseudo-randomness is generated 2519** internally and without recourse to the [sqlite3_vfs] xRandomness 2520** method. 2521*/ 2522SQLITE_API void SQLITE_STDCALL sqlite3_randomness(int N, void *P); 2523 2524/* 2525** CAPI3REF: Compile-Time Authorization Callbacks 2526** METHOD: sqlite3 2527** 2528** ^This routine registers an authorizer callback with a particular 2529** [database connection], supplied in the first argument. 2530** ^The authorizer callback is invoked as SQL statements are being compiled 2531** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2532** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2533** points during the compilation process, as logic is being created 2534** to perform various actions, the authorizer callback is invoked to 2535** see if those actions are allowed. ^The authorizer callback should 2536** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2537** specific action but allow the SQL statement to continue to be 2538** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2539** rejected with an error. ^If the authorizer callback returns 2540** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2541** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2542** the authorizer will fail with an error message. 2543** 2544** When the callback returns [SQLITE_OK], that means the operation 2545** requested is ok. ^When the callback returns [SQLITE_DENY], the 2546** [sqlite3_prepare_v2()] or equivalent call that triggered the 2547** authorizer will fail with an error message explaining that 2548** access is denied. 2549** 2550** ^The first parameter to the authorizer callback is a copy of the third 2551** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2552** to the callback is an integer [SQLITE_COPY | action code] that specifies 2553** the particular action to be authorized. ^The third through sixth parameters 2554** to the callback are zero-terminated strings that contain additional 2555** details about the action to be authorized. 2556** 2557** ^If the action code is [SQLITE_READ] 2558** and the callback returns [SQLITE_IGNORE] then the 2559** [prepared statement] statement is constructed to substitute 2560** a NULL value in place of the table column that would have 2561** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2562** return can be used to deny an untrusted user access to individual 2563** columns of a table. 2564** ^If the action code is [SQLITE_DELETE] and the callback returns 2565** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2566** [truncate optimization] is disabled and all rows are deleted individually. 2567** 2568** An authorizer is used when [sqlite3_prepare | preparing] 2569** SQL statements from an untrusted source, to ensure that the SQL statements 2570** do not try to access data they are not allowed to see, or that they do not 2571** try to execute malicious statements that damage the database. For 2572** example, an application may allow a user to enter arbitrary 2573** SQL queries for evaluation by a database. But the application does 2574** not want the user to be able to make arbitrary changes to the 2575** database. An authorizer could then be put in place while the 2576** user-entered SQL is being [sqlite3_prepare | prepared] that 2577** disallows everything except [SELECT] statements. 2578** 2579** Applications that need to process SQL from untrusted sources 2580** might also consider lowering resource limits using [sqlite3_limit()] 2581** and limiting database size using the [max_page_count] [PRAGMA] 2582** in addition to using an authorizer. 2583** 2584** ^(Only a single authorizer can be in place on a database connection 2585** at a time. Each call to sqlite3_set_authorizer overrides the 2586** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2587** The authorizer is disabled by default. 2588** 2589** The authorizer callback must not do anything that will modify 2590** the database connection that invoked the authorizer callback. 2591** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2592** database connections for the meaning of "modify" in this paragraph. 2593** 2594** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2595** statement might be re-prepared during [sqlite3_step()] due to a 2596** schema change. Hence, the application should ensure that the 2597** correct authorizer callback remains in place during the [sqlite3_step()]. 2598** 2599** ^Note that the authorizer callback is invoked only during 2600** [sqlite3_prepare()] or its variants. Authorization is not 2601** performed during statement evaluation in [sqlite3_step()], unless 2602** as stated in the previous paragraph, sqlite3_step() invokes 2603** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2604*/ 2605SQLITE_API int SQLITE_STDCALL sqlite3_set_authorizer( 2606 sqlite3*, 2607 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2608 void *pUserData 2609); 2610 2611/* 2612** CAPI3REF: Authorizer Return Codes 2613** 2614** The [sqlite3_set_authorizer | authorizer callback function] must 2615** return either [SQLITE_OK] or one of these two constants in order 2616** to signal SQLite whether or not the action is permitted. See the 2617** [sqlite3_set_authorizer | authorizer documentation] for additional 2618** information. 2619** 2620** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2621** returned from the [sqlite3_vtab_on_conflict()] interface. 2622*/ 2623#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2624#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2625 2626/* 2627** CAPI3REF: Authorizer Action Codes 2628** 2629** The [sqlite3_set_authorizer()] interface registers a callback function 2630** that is invoked to authorize certain SQL statement actions. The 2631** second parameter to the callback is an integer code that specifies 2632** what action is being authorized. These are the integer action codes that 2633** the authorizer callback may be passed. 2634** 2635** These action code values signify what kind of operation is to be 2636** authorized. The 3rd and 4th parameters to the authorization 2637** callback function will be parameters or NULL depending on which of these 2638** codes is used as the second parameter. ^(The 5th parameter to the 2639** authorizer callback is the name of the database ("main", "temp", 2640** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2641** is the name of the inner-most trigger or view that is responsible for 2642** the access attempt or NULL if this access attempt is directly from 2643** top-level SQL code. 2644*/ 2645/******************************************* 3rd ************ 4th ***********/ 2646#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2647#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2648#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2649#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2650#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2651#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2652#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2653#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2654#define SQLITE_DELETE 9 /* Table Name NULL */ 2655#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2656#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2657#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2658#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2659#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2660#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2661#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2662#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2663#define SQLITE_INSERT 18 /* Table Name NULL */ 2664#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2665#define SQLITE_READ 20 /* Table Name Column Name */ 2666#define SQLITE_SELECT 21 /* NULL NULL */ 2667#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2668#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2669#define SQLITE_ATTACH 24 /* Filename NULL */ 2670#define SQLITE_DETACH 25 /* Database Name NULL */ 2671#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2672#define SQLITE_REINDEX 27 /* Index Name NULL */ 2673#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2674#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2675#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2676#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2677#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2678#define SQLITE_COPY 0 /* No longer used */ 2679#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2680 2681/* 2682** CAPI3REF: Tracing And Profiling Functions 2683** METHOD: sqlite3 2684** 2685** These routines register callback functions that can be used for 2686** tracing and profiling the execution of SQL statements. 2687** 2688** ^The callback function registered by sqlite3_trace() is invoked at 2689** various times when an SQL statement is being run by [sqlite3_step()]. 2690** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2691** SQL statement text as the statement first begins executing. 2692** ^(Additional sqlite3_trace() callbacks might occur 2693** as each triggered subprogram is entered. The callbacks for triggers 2694** contain a UTF-8 SQL comment that identifies the trigger.)^ 2695** 2696** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2697** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2698** 2699** ^The callback function registered by sqlite3_profile() is invoked 2700** as each SQL statement finishes. ^The profile callback contains 2701** the original statement text and an estimate of wall-clock time 2702** of how long that statement took to run. ^The profile callback 2703** time is in units of nanoseconds, however the current implementation 2704** is only capable of millisecond resolution so the six least significant 2705** digits in the time are meaningless. Future versions of SQLite 2706** might provide greater resolution on the profiler callback. The 2707** sqlite3_profile() function is considered experimental and is 2708** subject to change in future versions of SQLite. 2709*/ 2710SQLITE_API void *SQLITE_STDCALL sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2711SQLITE_API SQLITE_EXPERIMENTAL void *SQLITE_STDCALL sqlite3_profile(sqlite3*, 2712 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2713 2714/* 2715** CAPI3REF: Query Progress Callbacks 2716** METHOD: sqlite3 2717** 2718** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2719** function X to be invoked periodically during long running calls to 2720** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2721** database connection D. An example use for this 2722** interface is to keep a GUI updated during a large query. 2723** 2724** ^The parameter P is passed through as the only parameter to the 2725** callback function X. ^The parameter N is the approximate number of 2726** [virtual machine instructions] that are evaluated between successive 2727** invocations of the callback X. ^If N is less than one then the progress 2728** handler is disabled. 2729** 2730** ^Only a single progress handler may be defined at one time per 2731** [database connection]; setting a new progress handler cancels the 2732** old one. ^Setting parameter X to NULL disables the progress handler. 2733** ^The progress handler is also disabled by setting N to a value less 2734** than 1. 2735** 2736** ^If the progress callback returns non-zero, the operation is 2737** interrupted. This feature can be used to implement a 2738** "Cancel" button on a GUI progress dialog box. 2739** 2740** The progress handler callback must not do anything that will modify 2741** the database connection that invoked the progress handler. 2742** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2743** database connections for the meaning of "modify" in this paragraph. 2744** 2745*/ 2746SQLITE_API void SQLITE_STDCALL sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2747 2748/* 2749** CAPI3REF: Opening A New Database Connection 2750** CONSTRUCTOR: sqlite3 2751** 2752** ^These routines open an SQLite database file as specified by the 2753** filename argument. ^The filename argument is interpreted as UTF-8 for 2754** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2755** order for sqlite3_open16(). ^(A [database connection] handle is usually 2756** returned in *ppDb, even if an error occurs. The only exception is that 2757** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2758** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2759** object.)^ ^(If the database is opened (and/or created) successfully, then 2760** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2761** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2762** an English language description of the error following a failure of any 2763** of the sqlite3_open() routines. 2764** 2765** ^The default encoding will be UTF-8 for databases created using 2766** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 2767** created using sqlite3_open16() will be UTF-16 in the native byte order. 2768** 2769** Whether or not an error occurs when it is opened, resources 2770** associated with the [database connection] handle should be released by 2771** passing it to [sqlite3_close()] when it is no longer required. 2772** 2773** The sqlite3_open_v2() interface works like sqlite3_open() 2774** except that it accepts two additional parameters for additional control 2775** over the new database connection. ^(The flags parameter to 2776** sqlite3_open_v2() can take one of 2777** the following three values, optionally combined with the 2778** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2779** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2780** 2781** <dl> 2782** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2783** <dd>The database is opened in read-only mode. If the database does not 2784** already exist, an error is returned.</dd>)^ 2785** 2786** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2787** <dd>The database is opened for reading and writing if possible, or reading 2788** only if the file is write protected by the operating system. In either 2789** case the database must already exist, otherwise an error is returned.</dd>)^ 2790** 2791** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2792** <dd>The database is opened for reading and writing, and is created if 2793** it does not already exist. This is the behavior that is always used for 2794** sqlite3_open() and sqlite3_open16().</dd>)^ 2795** </dl> 2796** 2797** If the 3rd parameter to sqlite3_open_v2() is not one of the 2798** combinations shown above optionally combined with other 2799** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2800** then the behavior is undefined. 2801** 2802** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2803** opens in the multi-thread [threading mode] as long as the single-thread 2804** mode has not been set at compile-time or start-time. ^If the 2805** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2806** in the serialized [threading mode] unless single-thread was 2807** previously selected at compile-time or start-time. 2808** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2809** eligible to use [shared cache mode], regardless of whether or not shared 2810** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2811** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2812** participate in [shared cache mode] even if it is enabled. 2813** 2814** ^The fourth parameter to sqlite3_open_v2() is the name of the 2815** [sqlite3_vfs] object that defines the operating system interface that 2816** the new database connection should use. ^If the fourth parameter is 2817** a NULL pointer then the default [sqlite3_vfs] object is used. 2818** 2819** ^If the filename is ":memory:", then a private, temporary in-memory database 2820** is created for the connection. ^This in-memory database will vanish when 2821** the database connection is closed. Future versions of SQLite might 2822** make use of additional special filenames that begin with the ":" character. 2823** It is recommended that when a database filename actually does begin with 2824** a ":" character you should prefix the filename with a pathname such as 2825** "./" to avoid ambiguity. 2826** 2827** ^If the filename is an empty string, then a private, temporary 2828** on-disk database will be created. ^This private database will be 2829** automatically deleted as soon as the database connection is closed. 2830** 2831** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2832** 2833** ^If [URI filename] interpretation is enabled, and the filename argument 2834** begins with "file:", then the filename is interpreted as a URI. ^URI 2835** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2836** set in the fourth argument to sqlite3_open_v2(), or if it has 2837** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2838** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2839** As of SQLite version 3.7.7, URI filename interpretation is turned off 2840** by default, but future releases of SQLite might enable URI filename 2841** interpretation by default. See "[URI filenames]" for additional 2842** information. 2843** 2844** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2845** authority, then it must be either an empty string or the string 2846** "localhost". ^If the authority is not an empty string or "localhost", an 2847** error is returned to the caller. ^The fragment component of a URI, if 2848** present, is ignored. 2849** 2850** ^SQLite uses the path component of the URI as the name of the disk file 2851** which contains the database. ^If the path begins with a '/' character, 2852** then it is interpreted as an absolute path. ^If the path does not begin 2853** with a '/' (meaning that the authority section is omitted from the URI) 2854** then the path is interpreted as a relative path. 2855** ^(On windows, the first component of an absolute path 2856** is a drive specification (e.g. "C:").)^ 2857** 2858** [[core URI query parameters]] 2859** The query component of a URI may contain parameters that are interpreted 2860** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2861** SQLite and its built-in [VFSes] interpret the 2862** following query parameters: 2863** 2864** <ul> 2865** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2866** a VFS object that provides the operating system interface that should 2867** be used to access the database file on disk. ^If this option is set to 2868** an empty string the default VFS object is used. ^Specifying an unknown 2869** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2870** present, then the VFS specified by the option takes precedence over 2871** the value passed as the fourth parameter to sqlite3_open_v2(). 2872** 2873** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2874** "rwc", or "memory". Attempting to set it to any other value is 2875** an error)^. 2876** ^If "ro" is specified, then the database is opened for read-only 2877** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2878** third argument to sqlite3_open_v2(). ^If the mode option is set to 2879** "rw", then the database is opened for read-write (but not create) 2880** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2881** been set. ^Value "rwc" is equivalent to setting both 2882** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2883** set to "memory" then a pure [in-memory database] that never reads 2884** or writes from disk is used. ^It is an error to specify a value for 2885** the mode parameter that is less restrictive than that specified by 2886** the flags passed in the third parameter to sqlite3_open_v2(). 2887** 2888** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2889** "private". ^Setting it to "shared" is equivalent to setting the 2890** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2891** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2892** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2893** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2894** a URI filename, its value overrides any behavior requested by setting 2895** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2896** 2897** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 2898** [powersafe overwrite] property does or does not apply to the 2899** storage media on which the database file resides. 2900** 2901** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 2902** which if set disables file locking in rollback journal modes. This 2903** is useful for accessing a database on a filesystem that does not 2904** support locking. Caution: Database corruption might result if two 2905** or more processes write to the same database and any one of those 2906** processes uses nolock=1. 2907** 2908** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 2909** parameter that indicates that the database file is stored on 2910** read-only media. ^When immutable is set, SQLite assumes that the 2911** database file cannot be changed, even by a process with higher 2912** privilege, and so the database is opened read-only and all locking 2913** and change detection is disabled. Caution: Setting the immutable 2914** property on a database file that does in fact change can result 2915** in incorrect query results and/or [SQLITE_CORRUPT] errors. 2916** See also: [SQLITE_IOCAP_IMMUTABLE]. 2917** 2918** </ul> 2919** 2920** ^Specifying an unknown parameter in the query component of a URI is not an 2921** error. Future versions of SQLite might understand additional query 2922** parameters. See "[query parameters with special meaning to SQLite]" for 2923** additional information. 2924** 2925** [[URI filename examples]] <h3>URI filename examples</h3> 2926** 2927** <table border="1" align=center cellpadding=5> 2928** <tr><th> URI filenames <th> Results 2929** <tr><td> file:data.db <td> 2930** Open the file "data.db" in the current directory. 2931** <tr><td> file:/home/fred/data.db<br> 2932** file:///home/fred/data.db <br> 2933** file://localhost/home/fred/data.db <br> <td> 2934** Open the database file "/home/fred/data.db". 2935** <tr><td> file://darkstar/home/fred/data.db <td> 2936** An error. "darkstar" is not a recognized authority. 2937** <tr><td style="white-space:nowrap"> 2938** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2939** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2940** C:. Note that the %20 escaping in this example is not strictly 2941** necessary - space characters can be used literally 2942** in URI filenames. 2943** <tr><td> file:data.db?mode=ro&cache=private <td> 2944** Open file "data.db" in the current directory for read-only access. 2945** Regardless of whether or not shared-cache mode is enabled by 2946** default, use a private cache. 2947** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 2948** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 2949** that uses dot-files in place of posix advisory locking. 2950** <tr><td> file:data.db?mode=readonly <td> 2951** An error. "readonly" is not a valid option for the "mode" parameter. 2952** </table> 2953** 2954** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2955** query components of a URI. A hexadecimal escape sequence consists of a 2956** percent sign - "%" - followed by exactly two hexadecimal digits 2957** specifying an octet value. ^Before the path or query components of a 2958** URI filename are interpreted, they are encoded using UTF-8 and all 2959** hexadecimal escape sequences replaced by a single byte containing the 2960** corresponding octet. If this process generates an invalid UTF-8 encoding, 2961** the results are undefined. 2962** 2963** <b>Note to Windows users:</b> The encoding used for the filename argument 2964** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2965** codepage is currently defined. Filenames containing international 2966** characters must be converted to UTF-8 prior to passing them into 2967** sqlite3_open() or sqlite3_open_v2(). 2968** 2969** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2970** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2971** features that require the use of temporary files may fail. 2972** 2973** See also: [sqlite3_temp_directory] 2974*/ 2975SQLITE_API int SQLITE_STDCALL sqlite3_open( 2976 const char *filename, /* Database filename (UTF-8) */ 2977 sqlite3 **ppDb /* OUT: SQLite db handle */ 2978); 2979SQLITE_API int SQLITE_STDCALL sqlite3_open16( 2980 const void *filename, /* Database filename (UTF-16) */ 2981 sqlite3 **ppDb /* OUT: SQLite db handle */ 2982); 2983SQLITE_API int SQLITE_STDCALL sqlite3_open_v2( 2984 const char *filename, /* Database filename (UTF-8) */ 2985 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2986 int flags, /* Flags */ 2987 const char *zVfs /* Name of VFS module to use */ 2988); 2989 2990/* 2991** CAPI3REF: Obtain Values For URI Parameters 2992** 2993** These are utility routines, useful to VFS implementations, that check 2994** to see if a database file was a URI that contained a specific query 2995** parameter, and if so obtains the value of that query parameter. 2996** 2997** If F is the database filename pointer passed into the xOpen() method of 2998** a VFS implementation when the flags parameter to xOpen() has one or 2999** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3000** P is the name of the query parameter, then 3001** sqlite3_uri_parameter(F,P) returns the value of the P 3002** parameter if it exists or a NULL pointer if P does not appear as a 3003** query parameter on F. If P is a query parameter of F 3004** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3005** a pointer to an empty string. 3006** 3007** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3008** parameter and returns true (1) or false (0) according to the value 3009** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3010** value of query parameter P is one of "yes", "true", or "on" in any 3011** case or if the value begins with a non-zero number. The 3012** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3013** query parameter P is one of "no", "false", or "off" in any case or 3014** if the value begins with a numeric zero. If P is not a query 3015** parameter on F or if the value of P is does not match any of the 3016** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3017** 3018** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3019** 64-bit signed integer and returns that integer, or D if P does not 3020** exist. If the value of P is something other than an integer, then 3021** zero is returned. 3022** 3023** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3024** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3025** is not a database file pathname pointer that SQLite passed into the xOpen 3026** VFS method, then the behavior of this routine is undefined and probably 3027** undesirable. 3028*/ 3029SQLITE_API const char *SQLITE_STDCALL sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3030SQLITE_API int SQLITE_STDCALL sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3031SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3032 3033 3034/* 3035** CAPI3REF: Error Codes And Messages 3036** METHOD: sqlite3 3037** 3038** ^If the most recent sqlite3_* API call associated with 3039** [database connection] D failed, then the sqlite3_errcode(D) interface 3040** returns the numeric [result code] or [extended result code] for that 3041** API call. 3042** If the most recent API call was successful, 3043** then the return value from sqlite3_errcode() is undefined. 3044** ^The sqlite3_extended_errcode() 3045** interface is the same except that it always returns the 3046** [extended result code] even when extended result codes are 3047** disabled. 3048** 3049** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3050** text that describes the error, as either UTF-8 or UTF-16 respectively. 3051** ^(Memory to hold the error message string is managed internally. 3052** The application does not need to worry about freeing the result. 3053** However, the error string might be overwritten or deallocated by 3054** subsequent calls to other SQLite interface functions.)^ 3055** 3056** ^The sqlite3_errstr() interface returns the English-language text 3057** that describes the [result code], as UTF-8. 3058** ^(Memory to hold the error message string is managed internally 3059** and must not be freed by the application)^. 3060** 3061** When the serialized [threading mode] is in use, it might be the 3062** case that a second error occurs on a separate thread in between 3063** the time of the first error and the call to these interfaces. 3064** When that happens, the second error will be reported since these 3065** interfaces always report the most recent result. To avoid 3066** this, each thread can obtain exclusive use of the [database connection] D 3067** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3068** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3069** all calls to the interfaces listed here are completed. 3070** 3071** If an interface fails with SQLITE_MISUSE, that means the interface 3072** was invoked incorrectly by the application. In that case, the 3073** error code and message may or may not be set. 3074*/ 3075SQLITE_API int SQLITE_STDCALL sqlite3_errcode(sqlite3 *db); 3076SQLITE_API int SQLITE_STDCALL sqlite3_extended_errcode(sqlite3 *db); 3077SQLITE_API const char *SQLITE_STDCALL sqlite3_errmsg(sqlite3*); 3078SQLITE_API const void *SQLITE_STDCALL sqlite3_errmsg16(sqlite3*); 3079SQLITE_API const char *SQLITE_STDCALL sqlite3_errstr(int); 3080 3081/* 3082** CAPI3REF: Prepared Statement Object 3083** KEYWORDS: {prepared statement} {prepared statements} 3084** 3085** An instance of this object represents a single SQL statement that 3086** has been compiled into binary form and is ready to be evaluated. 3087** 3088** Think of each SQL statement as a separate computer program. The 3089** original SQL text is source code. A prepared statement object 3090** is the compiled object code. All SQL must be converted into a 3091** prepared statement before it can be run. 3092** 3093** The life-cycle of a prepared statement object usually goes like this: 3094** 3095** <ol> 3096** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3097** <li> Bind values to [parameters] using the sqlite3_bind_*() 3098** interfaces. 3099** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3100** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3101** to step 2. Do this zero or more times. 3102** <li> Destroy the object using [sqlite3_finalize()]. 3103** </ol> 3104*/ 3105typedef struct sqlite3_stmt sqlite3_stmt; 3106 3107/* 3108** CAPI3REF: Run-time Limits 3109** METHOD: sqlite3 3110** 3111** ^(This interface allows the size of various constructs to be limited 3112** on a connection by connection basis. The first parameter is the 3113** [database connection] whose limit is to be set or queried. The 3114** second parameter is one of the [limit categories] that define a 3115** class of constructs to be size limited. The third parameter is the 3116** new limit for that construct.)^ 3117** 3118** ^If the new limit is a negative number, the limit is unchanged. 3119** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3120** [limits | hard upper bound] 3121** set at compile-time by a C preprocessor macro called 3122** [limits | SQLITE_MAX_<i>NAME</i>]. 3123** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3124** ^Attempts to increase a limit above its hard upper bound are 3125** silently truncated to the hard upper bound. 3126** 3127** ^Regardless of whether or not the limit was changed, the 3128** [sqlite3_limit()] interface returns the prior value of the limit. 3129** ^Hence, to find the current value of a limit without changing it, 3130** simply invoke this interface with the third parameter set to -1. 3131** 3132** Run-time limits are intended for use in applications that manage 3133** both their own internal database and also databases that are controlled 3134** by untrusted external sources. An example application might be a 3135** web browser that has its own databases for storing history and 3136** separate databases controlled by JavaScript applications downloaded 3137** off the Internet. The internal databases can be given the 3138** large, default limits. Databases managed by external sources can 3139** be given much smaller limits designed to prevent a denial of service 3140** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3141** interface to further control untrusted SQL. The size of the database 3142** created by an untrusted script can be contained using the 3143** [max_page_count] [PRAGMA]. 3144** 3145** New run-time limit categories may be added in future releases. 3146*/ 3147SQLITE_API int SQLITE_STDCALL sqlite3_limit(sqlite3*, int id, int newVal); 3148 3149/* 3150** CAPI3REF: Run-Time Limit Categories 3151** KEYWORDS: {limit category} {*limit categories} 3152** 3153** These constants define various performance limits 3154** that can be lowered at run-time using [sqlite3_limit()]. 3155** The synopsis of the meanings of the various limits is shown below. 3156** Additional information is available at [limits | Limits in SQLite]. 3157** 3158** <dl> 3159** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3160** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3161** 3162** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3163** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3164** 3165** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3166** <dd>The maximum number of columns in a table definition or in the 3167** result set of a [SELECT] or the maximum number of columns in an index 3168** or in an ORDER BY or GROUP BY clause.</dd>)^ 3169** 3170** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3171** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3172** 3173** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3174** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3175** 3176** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3177** <dd>The maximum number of instructions in a virtual machine program 3178** used to implement an SQL statement. This limit is not currently 3179** enforced, though that might be added in some future release of 3180** SQLite.</dd>)^ 3181** 3182** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3183** <dd>The maximum number of arguments on a function.</dd>)^ 3184** 3185** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3186** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3187** 3188** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3189** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3190** <dd>The maximum length of the pattern argument to the [LIKE] or 3191** [GLOB] operators.</dd>)^ 3192** 3193** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3194** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3195** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3196** 3197** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3198** <dd>The maximum depth of recursion for triggers.</dd>)^ 3199** 3200** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3201** <dd>The maximum number of auxiliary worker threads that a single 3202** [prepared statement] may start.</dd>)^ 3203** </dl> 3204*/ 3205#define SQLITE_LIMIT_LENGTH 0 3206#define SQLITE_LIMIT_SQL_LENGTH 1 3207#define SQLITE_LIMIT_COLUMN 2 3208#define SQLITE_LIMIT_EXPR_DEPTH 3 3209#define SQLITE_LIMIT_COMPOUND_SELECT 4 3210#define SQLITE_LIMIT_VDBE_OP 5 3211#define SQLITE_LIMIT_FUNCTION_ARG 6 3212#define SQLITE_LIMIT_ATTACHED 7 3213#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3214#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3215#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3216#define SQLITE_LIMIT_WORKER_THREADS 11 3217 3218/* 3219** CAPI3REF: Compiling An SQL Statement 3220** KEYWORDS: {SQL statement compiler} 3221** METHOD: sqlite3 3222** CONSTRUCTOR: sqlite3_stmt 3223** 3224** To execute an SQL query, it must first be compiled into a byte-code 3225** program using one of these routines. 3226** 3227** The first argument, "db", is a [database connection] obtained from a 3228** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3229** [sqlite3_open16()]. The database connection must not have been closed. 3230** 3231** The second argument, "zSql", is the statement to be compiled, encoded 3232** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3233** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3234** use UTF-16. 3235** 3236** ^If the nByte argument is negative, then zSql is read up to the 3237** first zero terminator. ^If nByte is positive, then it is the 3238** number of bytes read from zSql. ^If nByte is zero, then no prepared 3239** statement is generated. 3240** If the caller knows that the supplied string is nul-terminated, then 3241** there is a small performance advantage to passing an nByte parameter that 3242** is the number of bytes in the input string <i>including</i> 3243** the nul-terminator. 3244** 3245** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3246** past the end of the first SQL statement in zSql. These routines only 3247** compile the first statement in zSql, so *pzTail is left pointing to 3248** what remains uncompiled. 3249** 3250** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3251** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3252** to NULL. ^If the input text contains no SQL (if the input is an empty 3253** string or a comment) then *ppStmt is set to NULL. 3254** The calling procedure is responsible for deleting the compiled 3255** SQL statement using [sqlite3_finalize()] after it has finished with it. 3256** ppStmt may not be NULL. 3257** 3258** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3259** otherwise an [error code] is returned. 3260** 3261** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3262** recommended for all new programs. The two older interfaces are retained 3263** for backwards compatibility, but their use is discouraged. 3264** ^In the "v2" interfaces, the prepared statement 3265** that is returned (the [sqlite3_stmt] object) contains a copy of the 3266** original SQL text. This causes the [sqlite3_step()] interface to 3267** behave differently in three ways: 3268** 3269** <ol> 3270** <li> 3271** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3272** always used to do, [sqlite3_step()] will automatically recompile the SQL 3273** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3274** retries will occur before sqlite3_step() gives up and returns an error. 3275** </li> 3276** 3277** <li> 3278** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3279** [error codes] or [extended error codes]. ^The legacy behavior was that 3280** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3281** and the application would have to make a second call to [sqlite3_reset()] 3282** in order to find the underlying cause of the problem. With the "v2" prepare 3283** interfaces, the underlying reason for the error is returned immediately. 3284** </li> 3285** 3286** <li> 3287** ^If the specific value bound to [parameter | host parameter] in the 3288** WHERE clause might influence the choice of query plan for a statement, 3289** then the statement will be automatically recompiled, as if there had been 3290** a schema change, on the first [sqlite3_step()] call following any change 3291** to the [sqlite3_bind_text | bindings] of that [parameter]. 3292** ^The specific value of WHERE-clause [parameter] might influence the 3293** choice of query plan if the parameter is the left-hand side of a [LIKE] 3294** or [GLOB] operator or if the parameter is compared to an indexed column 3295** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3296** </li> 3297** </ol> 3298*/ 3299SQLITE_API int SQLITE_STDCALL sqlite3_prepare( 3300 sqlite3 *db, /* Database handle */ 3301 const char *zSql, /* SQL statement, UTF-8 encoded */ 3302 int nByte, /* Maximum length of zSql in bytes. */ 3303 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3304 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3305); 3306SQLITE_API int SQLITE_STDCALL sqlite3_prepare_v2( 3307 sqlite3 *db, /* Database handle */ 3308 const char *zSql, /* SQL statement, UTF-8 encoded */ 3309 int nByte, /* Maximum length of zSql in bytes. */ 3310 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3311 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3312); 3313SQLITE_API int SQLITE_STDCALL sqlite3_prepare16( 3314 sqlite3 *db, /* Database handle */ 3315 const void *zSql, /* SQL statement, UTF-16 encoded */ 3316 int nByte, /* Maximum length of zSql in bytes. */ 3317 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3318 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3319); 3320SQLITE_API int SQLITE_STDCALL sqlite3_prepare16_v2( 3321 sqlite3 *db, /* Database handle */ 3322 const void *zSql, /* SQL statement, UTF-16 encoded */ 3323 int nByte, /* Maximum length of zSql in bytes. */ 3324 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3325 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3326); 3327 3328/* 3329** CAPI3REF: Retrieving Statement SQL 3330** METHOD: sqlite3_stmt 3331** 3332** ^This interface can be used to retrieve a saved copy of the original 3333** SQL text used to create a [prepared statement] if that statement was 3334** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3335*/ 3336SQLITE_API const char *SQLITE_STDCALL sqlite3_sql(sqlite3_stmt *pStmt); 3337 3338/* 3339** CAPI3REF: Determine If An SQL Statement Writes The Database 3340** METHOD: sqlite3_stmt 3341** 3342** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3343** and only if the [prepared statement] X makes no direct changes to 3344** the content of the database file. 3345** 3346** Note that [application-defined SQL functions] or 3347** [virtual tables] might change the database indirectly as a side effect. 3348** ^(For example, if an application defines a function "eval()" that 3349** calls [sqlite3_exec()], then the following SQL statement would 3350** change the database file through side-effects: 3351** 3352** <blockquote><pre> 3353** SELECT eval('DELETE FROM t1') FROM t2; 3354** </pre></blockquote> 3355** 3356** But because the [SELECT] statement does not change the database file 3357** directly, sqlite3_stmt_readonly() would still return true.)^ 3358** 3359** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3360** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3361** since the statements themselves do not actually modify the database but 3362** rather they control the timing of when other statements modify the 3363** database. ^The [ATTACH] and [DETACH] statements also cause 3364** sqlite3_stmt_readonly() to return true since, while those statements 3365** change the configuration of a database connection, they do not make 3366** changes to the content of the database files on disk. 3367*/ 3368SQLITE_API int SQLITE_STDCALL sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3369 3370/* 3371** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3372** METHOD: sqlite3_stmt 3373** 3374** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3375** [prepared statement] S has been stepped at least once using 3376** [sqlite3_step(S)] but has not run to completion and/or has not 3377** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3378** interface returns false if S is a NULL pointer. If S is not a 3379** NULL pointer and is not a pointer to a valid [prepared statement] 3380** object, then the behavior is undefined and probably undesirable. 3381** 3382** This interface can be used in combination [sqlite3_next_stmt()] 3383** to locate all prepared statements associated with a database 3384** connection that are in need of being reset. This can be used, 3385** for example, in diagnostic routines to search for prepared 3386** statements that are holding a transaction open. 3387*/ 3388SQLITE_API int SQLITE_STDCALL sqlite3_stmt_busy(sqlite3_stmt*); 3389 3390/* 3391** CAPI3REF: Dynamically Typed Value Object 3392** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3393** 3394** SQLite uses the sqlite3_value object to represent all values 3395** that can be stored in a database table. SQLite uses dynamic typing 3396** for the values it stores. ^Values stored in sqlite3_value objects 3397** can be integers, floating point values, strings, BLOBs, or NULL. 3398** 3399** An sqlite3_value object may be either "protected" or "unprotected". 3400** Some interfaces require a protected sqlite3_value. Other interfaces 3401** will accept either a protected or an unprotected sqlite3_value. 3402** Every interface that accepts sqlite3_value arguments specifies 3403** whether or not it requires a protected sqlite3_value. The 3404** [sqlite3_value_dup()] interface can be used to construct a new 3405** protected sqlite3_value from an unprotected sqlite3_value. 3406** 3407** The terms "protected" and "unprotected" refer to whether or not 3408** a mutex is held. An internal mutex is held for a protected 3409** sqlite3_value object but no mutex is held for an unprotected 3410** sqlite3_value object. If SQLite is compiled to be single-threaded 3411** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3412** or if SQLite is run in one of reduced mutex modes 3413** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3414** then there is no distinction between protected and unprotected 3415** sqlite3_value objects and they can be used interchangeably. However, 3416** for maximum code portability it is recommended that applications 3417** still make the distinction between protected and unprotected 3418** sqlite3_value objects even when not strictly required. 3419** 3420** ^The sqlite3_value objects that are passed as parameters into the 3421** implementation of [application-defined SQL functions] are protected. 3422** ^The sqlite3_value object returned by 3423** [sqlite3_column_value()] is unprotected. 3424** Unprotected sqlite3_value objects may only be used with 3425** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3426** The [sqlite3_value_blob | sqlite3_value_type()] family of 3427** interfaces require protected sqlite3_value objects. 3428*/ 3429typedef struct Mem sqlite3_value; 3430 3431/* 3432** CAPI3REF: SQL Function Context Object 3433** 3434** The context in which an SQL function executes is stored in an 3435** sqlite3_context object. ^A pointer to an sqlite3_context object 3436** is always first parameter to [application-defined SQL functions]. 3437** The application-defined SQL function implementation will pass this 3438** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3439** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3440** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3441** and/or [sqlite3_set_auxdata()]. 3442*/ 3443typedef struct sqlite3_context sqlite3_context; 3444 3445/* 3446** CAPI3REF: Binding Values To Prepared Statements 3447** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3448** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3449** METHOD: sqlite3_stmt 3450** 3451** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3452** literals may be replaced by a [parameter] that matches one of following 3453** templates: 3454** 3455** <ul> 3456** <li> ? 3457** <li> ?NNN 3458** <li> :VVV 3459** <li> @VVV 3460** <li> $VVV 3461** </ul> 3462** 3463** In the templates above, NNN represents an integer literal, 3464** and VVV represents an alphanumeric identifier.)^ ^The values of these 3465** parameters (also called "host parameter names" or "SQL parameters") 3466** can be set using the sqlite3_bind_*() routines defined here. 3467** 3468** ^The first argument to the sqlite3_bind_*() routines is always 3469** a pointer to the [sqlite3_stmt] object returned from 3470** [sqlite3_prepare_v2()] or its variants. 3471** 3472** ^The second argument is the index of the SQL parameter to be set. 3473** ^The leftmost SQL parameter has an index of 1. ^When the same named 3474** SQL parameter is used more than once, second and subsequent 3475** occurrences have the same index as the first occurrence. 3476** ^The index for named parameters can be looked up using the 3477** [sqlite3_bind_parameter_index()] API if desired. ^The index 3478** for "?NNN" parameters is the value of NNN. 3479** ^The NNN value must be between 1 and the [sqlite3_limit()] 3480** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3481** 3482** ^The third argument is the value to bind to the parameter. 3483** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3484** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3485** is ignored and the end result is the same as sqlite3_bind_null(). 3486** 3487** ^(In those routines that have a fourth argument, its value is the 3488** number of bytes in the parameter. To be clear: the value is the 3489** number of <u>bytes</u> in the value, not the number of characters.)^ 3490** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3491** is negative, then the length of the string is 3492** the number of bytes up to the first zero terminator. 3493** If the fourth parameter to sqlite3_bind_blob() is negative, then 3494** the behavior is undefined. 3495** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3496** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3497** that parameter must be the byte offset 3498** where the NUL terminator would occur assuming the string were NUL 3499** terminated. If any NUL characters occur at byte offsets less than 3500** the value of the fourth parameter then the resulting string value will 3501** contain embedded NULs. The result of expressions involving strings 3502** with embedded NULs is undefined. 3503** 3504** ^The fifth argument to the BLOB and string binding interfaces 3505** is a destructor used to dispose of the BLOB or 3506** string after SQLite has finished with it. ^The destructor is called 3507** to dispose of the BLOB or string even if the call to bind API fails. 3508** ^If the fifth argument is 3509** the special value [SQLITE_STATIC], then SQLite assumes that the 3510** information is in static, unmanaged space and does not need to be freed. 3511** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3512** SQLite makes its own private copy of the data immediately, before 3513** the sqlite3_bind_*() routine returns. 3514** 3515** ^The sixth argument to sqlite3_bind_text64() must be one of 3516** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3517** to specify the encoding of the text in the third parameter. If 3518** the sixth argument to sqlite3_bind_text64() is not one of the 3519** allowed values shown above, or if the text encoding is different 3520** from the encoding specified by the sixth parameter, then the behavior 3521** is undefined. 3522** 3523** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3524** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3525** (just an integer to hold its size) while it is being processed. 3526** Zeroblobs are intended to serve as placeholders for BLOBs whose 3527** content is later written using 3528** [sqlite3_blob_open | incremental BLOB I/O] routines. 3529** ^A negative value for the zeroblob results in a zero-length BLOB. 3530** 3531** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3532** for the [prepared statement] or with a prepared statement for which 3533** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3534** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3535** routine is passed a [prepared statement] that has been finalized, the 3536** result is undefined and probably harmful. 3537** 3538** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3539** ^Unbound parameters are interpreted as NULL. 3540** 3541** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3542** [error code] if anything goes wrong. 3543** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3544** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3545** [SQLITE_MAX_LENGTH]. 3546** ^[SQLITE_RANGE] is returned if the parameter 3547** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3548** 3549** See also: [sqlite3_bind_parameter_count()], 3550** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3551*/ 3552SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3553SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3554 void(*)(void*)); 3555SQLITE_API int SQLITE_STDCALL sqlite3_bind_double(sqlite3_stmt*, int, double); 3556SQLITE_API int SQLITE_STDCALL sqlite3_bind_int(sqlite3_stmt*, int, int); 3557SQLITE_API int SQLITE_STDCALL sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3558SQLITE_API int SQLITE_STDCALL sqlite3_bind_null(sqlite3_stmt*, int); 3559SQLITE_API int SQLITE_STDCALL sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3560SQLITE_API int SQLITE_STDCALL sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3561SQLITE_API int SQLITE_STDCALL sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3562 void(*)(void*), unsigned char encoding); 3563SQLITE_API int SQLITE_STDCALL sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3564SQLITE_API int SQLITE_STDCALL sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3565SQLITE_API int SQLITE_STDCALL sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3566 3567/* 3568** CAPI3REF: Number Of SQL Parameters 3569** METHOD: sqlite3_stmt 3570** 3571** ^This routine can be used to find the number of [SQL parameters] 3572** in a [prepared statement]. SQL parameters are tokens of the 3573** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3574** placeholders for values that are [sqlite3_bind_blob | bound] 3575** to the parameters at a later time. 3576** 3577** ^(This routine actually returns the index of the largest (rightmost) 3578** parameter. For all forms except ?NNN, this will correspond to the 3579** number of unique parameters. If parameters of the ?NNN form are used, 3580** there may be gaps in the list.)^ 3581** 3582** See also: [sqlite3_bind_blob|sqlite3_bind()], 3583** [sqlite3_bind_parameter_name()], and 3584** [sqlite3_bind_parameter_index()]. 3585*/ 3586SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_count(sqlite3_stmt*); 3587 3588/* 3589** CAPI3REF: Name Of A Host Parameter 3590** METHOD: sqlite3_stmt 3591** 3592** ^The sqlite3_bind_parameter_name(P,N) interface returns 3593** the name of the N-th [SQL parameter] in the [prepared statement] P. 3594** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3595** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3596** respectively. 3597** In other words, the initial ":" or "$" or "@" or "?" 3598** is included as part of the name.)^ 3599** ^Parameters of the form "?" without a following integer have no name 3600** and are referred to as "nameless" or "anonymous parameters". 3601** 3602** ^The first host parameter has an index of 1, not 0. 3603** 3604** ^If the value N is out of range or if the N-th parameter is 3605** nameless, then NULL is returned. ^The returned string is 3606** always in UTF-8 encoding even if the named parameter was 3607** originally specified as UTF-16 in [sqlite3_prepare16()] or 3608** [sqlite3_prepare16_v2()]. 3609** 3610** See also: [sqlite3_bind_blob|sqlite3_bind()], 3611** [sqlite3_bind_parameter_count()], and 3612** [sqlite3_bind_parameter_index()]. 3613*/ 3614SQLITE_API const char *SQLITE_STDCALL sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3615 3616/* 3617** CAPI3REF: Index Of A Parameter With A Given Name 3618** METHOD: sqlite3_stmt 3619** 3620** ^Return the index of an SQL parameter given its name. ^The 3621** index value returned is suitable for use as the second 3622** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3623** is returned if no matching parameter is found. ^The parameter 3624** name must be given in UTF-8 even if the original statement 3625** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3626** 3627** See also: [sqlite3_bind_blob|sqlite3_bind()], 3628** [sqlite3_bind_parameter_count()], and 3629** [sqlite3_bind_parameter_index()]. 3630*/ 3631SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3632 3633/* 3634** CAPI3REF: Reset All Bindings On A Prepared Statement 3635** METHOD: sqlite3_stmt 3636** 3637** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3638** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3639** ^Use this routine to reset all host parameters to NULL. 3640*/ 3641SQLITE_API int SQLITE_STDCALL sqlite3_clear_bindings(sqlite3_stmt*); 3642 3643/* 3644** CAPI3REF: Number Of Columns In A Result Set 3645** METHOD: sqlite3_stmt 3646** 3647** ^Return the number of columns in the result set returned by the 3648** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3649** statement that does not return data (for example an [UPDATE]). 3650** 3651** See also: [sqlite3_data_count()] 3652*/ 3653SQLITE_API int SQLITE_STDCALL sqlite3_column_count(sqlite3_stmt *pStmt); 3654 3655/* 3656** CAPI3REF: Column Names In A Result Set 3657** METHOD: sqlite3_stmt 3658** 3659** ^These routines return the name assigned to a particular column 3660** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3661** interface returns a pointer to a zero-terminated UTF-8 string 3662** and sqlite3_column_name16() returns a pointer to a zero-terminated 3663** UTF-16 string. ^The first parameter is the [prepared statement] 3664** that implements the [SELECT] statement. ^The second parameter is the 3665** column number. ^The leftmost column is number 0. 3666** 3667** ^The returned string pointer is valid until either the [prepared statement] 3668** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3669** reprepared by the first call to [sqlite3_step()] for a particular run 3670** or until the next call to 3671** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3672** 3673** ^If sqlite3_malloc() fails during the processing of either routine 3674** (for example during a conversion from UTF-8 to UTF-16) then a 3675** NULL pointer is returned. 3676** 3677** ^The name of a result column is the value of the "AS" clause for 3678** that column, if there is an AS clause. If there is no AS clause 3679** then the name of the column is unspecified and may change from 3680** one release of SQLite to the next. 3681*/ 3682SQLITE_API const char *SQLITE_STDCALL sqlite3_column_name(sqlite3_stmt*, int N); 3683SQLITE_API const void *SQLITE_STDCALL sqlite3_column_name16(sqlite3_stmt*, int N); 3684 3685/* 3686** CAPI3REF: Source Of Data In A Query Result 3687** METHOD: sqlite3_stmt 3688** 3689** ^These routines provide a means to determine the database, table, and 3690** table column that is the origin of a particular result column in 3691** [SELECT] statement. 3692** ^The name of the database or table or column can be returned as 3693** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3694** the database name, the _table_ routines return the table name, and 3695** the origin_ routines return the column name. 3696** ^The returned string is valid until the [prepared statement] is destroyed 3697** using [sqlite3_finalize()] or until the statement is automatically 3698** reprepared by the first call to [sqlite3_step()] for a particular run 3699** or until the same information is requested 3700** again in a different encoding. 3701** 3702** ^The names returned are the original un-aliased names of the 3703** database, table, and column. 3704** 3705** ^The first argument to these interfaces is a [prepared statement]. 3706** ^These functions return information about the Nth result column returned by 3707** the statement, where N is the second function argument. 3708** ^The left-most column is column 0 for these routines. 3709** 3710** ^If the Nth column returned by the statement is an expression or 3711** subquery and is not a column value, then all of these functions return 3712** NULL. ^These routine might also return NULL if a memory allocation error 3713** occurs. ^Otherwise, they return the name of the attached database, table, 3714** or column that query result column was extracted from. 3715** 3716** ^As with all other SQLite APIs, those whose names end with "16" return 3717** UTF-16 encoded strings and the other functions return UTF-8. 3718** 3719** ^These APIs are only available if the library was compiled with the 3720** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3721** 3722** If two or more threads call one or more of these routines against the same 3723** prepared statement and column at the same time then the results are 3724** undefined. 3725** 3726** If two or more threads call one or more 3727** [sqlite3_column_database_name | column metadata interfaces] 3728** for the same [prepared statement] and result column 3729** at the same time then the results are undefined. 3730*/ 3731SQLITE_API const char *SQLITE_STDCALL sqlite3_column_database_name(sqlite3_stmt*,int); 3732SQLITE_API const void *SQLITE_STDCALL sqlite3_column_database_name16(sqlite3_stmt*,int); 3733SQLITE_API const char *SQLITE_STDCALL sqlite3_column_table_name(sqlite3_stmt*,int); 3734SQLITE_API const void *SQLITE_STDCALL sqlite3_column_table_name16(sqlite3_stmt*,int); 3735SQLITE_API const char *SQLITE_STDCALL sqlite3_column_origin_name(sqlite3_stmt*,int); 3736SQLITE_API const void *SQLITE_STDCALL sqlite3_column_origin_name16(sqlite3_stmt*,int); 3737 3738/* 3739** CAPI3REF: Declared Datatype Of A Query Result 3740** METHOD: sqlite3_stmt 3741** 3742** ^(The first parameter is a [prepared statement]. 3743** If this statement is a [SELECT] statement and the Nth column of the 3744** returned result set of that [SELECT] is a table column (not an 3745** expression or subquery) then the declared type of the table 3746** column is returned.)^ ^If the Nth column of the result set is an 3747** expression or subquery, then a NULL pointer is returned. 3748** ^The returned string is always UTF-8 encoded. 3749** 3750** ^(For example, given the database schema: 3751** 3752** CREATE TABLE t1(c1 VARIANT); 3753** 3754** and the following statement to be compiled: 3755** 3756** SELECT c1 + 1, c1 FROM t1; 3757** 3758** this routine would return the string "VARIANT" for the second result 3759** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3760** 3761** ^SQLite uses dynamic run-time typing. ^So just because a column 3762** is declared to contain a particular type does not mean that the 3763** data stored in that column is of the declared type. SQLite is 3764** strongly typed, but the typing is dynamic not static. ^Type 3765** is associated with individual values, not with the containers 3766** used to hold those values. 3767*/ 3768SQLITE_API const char *SQLITE_STDCALL sqlite3_column_decltype(sqlite3_stmt*,int); 3769SQLITE_API const void *SQLITE_STDCALL sqlite3_column_decltype16(sqlite3_stmt*,int); 3770 3771/* 3772** CAPI3REF: Evaluate An SQL Statement 3773** METHOD: sqlite3_stmt 3774** 3775** After a [prepared statement] has been prepared using either 3776** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3777** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3778** must be called one or more times to evaluate the statement. 3779** 3780** The details of the behavior of the sqlite3_step() interface depend 3781** on whether the statement was prepared using the newer "v2" interface 3782** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3783** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3784** new "v2" interface is recommended for new applications but the legacy 3785** interface will continue to be supported. 3786** 3787** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3788** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3789** ^With the "v2" interface, any of the other [result codes] or 3790** [extended result codes] might be returned as well. 3791** 3792** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3793** database locks it needs to do its job. ^If the statement is a [COMMIT] 3794** or occurs outside of an explicit transaction, then you can retry the 3795** statement. If the statement is not a [COMMIT] and occurs within an 3796** explicit transaction then you should rollback the transaction before 3797** continuing. 3798** 3799** ^[SQLITE_DONE] means that the statement has finished executing 3800** successfully. sqlite3_step() should not be called again on this virtual 3801** machine without first calling [sqlite3_reset()] to reset the virtual 3802** machine back to its initial state. 3803** 3804** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3805** is returned each time a new row of data is ready for processing by the 3806** caller. The values may be accessed using the [column access functions]. 3807** sqlite3_step() is called again to retrieve the next row of data. 3808** 3809** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3810** violation) has occurred. sqlite3_step() should not be called again on 3811** the VM. More information may be found by calling [sqlite3_errmsg()]. 3812** ^With the legacy interface, a more specific error code (for example, 3813** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3814** can be obtained by calling [sqlite3_reset()] on the 3815** [prepared statement]. ^In the "v2" interface, 3816** the more specific error code is returned directly by sqlite3_step(). 3817** 3818** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3819** Perhaps it was called on a [prepared statement] that has 3820** already been [sqlite3_finalize | finalized] or on one that had 3821** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3822** be the case that the same database connection is being used by two or 3823** more threads at the same moment in time. 3824** 3825** For all versions of SQLite up to and including 3.6.23.1, a call to 3826** [sqlite3_reset()] was required after sqlite3_step() returned anything 3827** other than [SQLITE_ROW] before any subsequent invocation of 3828** sqlite3_step(). Failure to reset the prepared statement using 3829** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3830** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3831** calling [sqlite3_reset()] automatically in this circumstance rather 3832** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3833** break because any application that ever receives an SQLITE_MISUSE error 3834** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3835** can be used to restore the legacy behavior. 3836** 3837** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3838** API always returns a generic error code, [SQLITE_ERROR], following any 3839** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3840** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3841** specific [error codes] that better describes the error. 3842** We admit that this is a goofy design. The problem has been fixed 3843** with the "v2" interface. If you prepare all of your SQL statements 3844** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3845** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3846** then the more specific [error codes] are returned directly 3847** by sqlite3_step(). The use of the "v2" interface is recommended. 3848*/ 3849SQLITE_API int SQLITE_STDCALL sqlite3_step(sqlite3_stmt*); 3850 3851/* 3852** CAPI3REF: Number of columns in a result set 3853** METHOD: sqlite3_stmt 3854** 3855** ^The sqlite3_data_count(P) interface returns the number of columns in the 3856** current row of the result set of [prepared statement] P. 3857** ^If prepared statement P does not have results ready to return 3858** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3859** interfaces) then sqlite3_data_count(P) returns 0. 3860** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3861** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3862** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3863** will return non-zero if previous call to [sqlite3_step](P) returned 3864** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3865** where it always returns zero since each step of that multi-step 3866** pragma returns 0 columns of data. 3867** 3868** See also: [sqlite3_column_count()] 3869*/ 3870SQLITE_API int SQLITE_STDCALL sqlite3_data_count(sqlite3_stmt *pStmt); 3871 3872/* 3873** CAPI3REF: Fundamental Datatypes 3874** KEYWORDS: SQLITE_TEXT 3875** 3876** ^(Every value in SQLite has one of five fundamental datatypes: 3877** 3878** <ul> 3879** <li> 64-bit signed integer 3880** <li> 64-bit IEEE floating point number 3881** <li> string 3882** <li> BLOB 3883** <li> NULL 3884** </ul>)^ 3885** 3886** These constants are codes for each of those types. 3887** 3888** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3889** for a completely different meaning. Software that links against both 3890** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3891** SQLITE_TEXT. 3892*/ 3893#define SQLITE_INTEGER 1 3894#define SQLITE_FLOAT 2 3895#define SQLITE_BLOB 4 3896#define SQLITE_NULL 5 3897#ifdef SQLITE_TEXT 3898# undef SQLITE_TEXT 3899#else 3900# define SQLITE_TEXT 3 3901#endif 3902#define SQLITE3_TEXT 3 3903 3904/* 3905** CAPI3REF: Result Values From A Query 3906** KEYWORDS: {column access functions} 3907** METHOD: sqlite3_stmt 3908** 3909** ^These routines return information about a single column of the current 3910** result row of a query. ^In every case the first argument is a pointer 3911** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3912** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3913** and the second argument is the index of the column for which information 3914** should be returned. ^The leftmost column of the result set has the index 0. 3915** ^The number of columns in the result can be determined using 3916** [sqlite3_column_count()]. 3917** 3918** If the SQL statement does not currently point to a valid row, or if the 3919** column index is out of range, the result is undefined. 3920** These routines may only be called when the most recent call to 3921** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3922** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3923** If any of these routines are called after [sqlite3_reset()] or 3924** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3925** something other than [SQLITE_ROW], the results are undefined. 3926** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3927** are called from a different thread while any of these routines 3928** are pending, then the results are undefined. 3929** 3930** ^The sqlite3_column_type() routine returns the 3931** [SQLITE_INTEGER | datatype code] for the initial data type 3932** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3933** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3934** returned by sqlite3_column_type() is only meaningful if no type 3935** conversions have occurred as described below. After a type conversion, 3936** the value returned by sqlite3_column_type() is undefined. Future 3937** versions of SQLite may change the behavior of sqlite3_column_type() 3938** following a type conversion. 3939** 3940** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3941** routine returns the number of bytes in that BLOB or string. 3942** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3943** the string to UTF-8 and then returns the number of bytes. 3944** ^If the result is a numeric value then sqlite3_column_bytes() uses 3945** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3946** the number of bytes in that string. 3947** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3948** 3949** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3950** routine returns the number of bytes in that BLOB or string. 3951** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3952** the string to UTF-16 and then returns the number of bytes. 3953** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3954** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3955** the number of bytes in that string. 3956** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3957** 3958** ^The values returned by [sqlite3_column_bytes()] and 3959** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3960** of the string. ^For clarity: the values returned by 3961** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3962** bytes in the string, not the number of characters. 3963** 3964** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3965** even empty strings, are always zero-terminated. ^The return 3966** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3967** 3968** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 3969** [unprotected sqlite3_value] object. In a multithreaded environment, 3970** an unprotected sqlite3_value object may only be used safely with 3971** [sqlite3_bind_value()] and [sqlite3_result_value()]. 3972** If the [unprotected sqlite3_value] object returned by 3973** [sqlite3_column_value()] is used in any other way, including calls 3974** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3975** or [sqlite3_value_bytes()], the behavior is not threadsafe. 3976** 3977** These routines attempt to convert the value where appropriate. ^For 3978** example, if the internal representation is FLOAT and a text result 3979** is requested, [sqlite3_snprintf()] is used internally to perform the 3980** conversion automatically. ^(The following table details the conversions 3981** that are applied: 3982** 3983** <blockquote> 3984** <table border="1"> 3985** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3986** 3987** <tr><td> NULL <td> INTEGER <td> Result is 0 3988** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3989** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 3990** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 3991** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3992** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3993** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3994** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 3995** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3996** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 3997** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 3998** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 3999** <tr><td> TEXT <td> BLOB <td> No change 4000** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4001** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4002** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4003** </table> 4004** </blockquote>)^ 4005** 4006** Note that when type conversions occur, pointers returned by prior 4007** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4008** sqlite3_column_text16() may be invalidated. 4009** Type conversions and pointer invalidations might occur 4010** in the following cases: 4011** 4012** <ul> 4013** <li> The initial content is a BLOB and sqlite3_column_text() or 4014** sqlite3_column_text16() is called. A zero-terminator might 4015** need to be added to the string.</li> 4016** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4017** sqlite3_column_text16() is called. The content must be converted 4018** to UTF-16.</li> 4019** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4020** sqlite3_column_text() is called. The content must be converted 4021** to UTF-8.</li> 4022** </ul> 4023** 4024** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4025** not invalidate a prior pointer, though of course the content of the buffer 4026** that the prior pointer references will have been modified. Other kinds 4027** of conversion are done in place when it is possible, but sometimes they 4028** are not possible and in those cases prior pointers are invalidated. 4029** 4030** The safest policy is to invoke these routines 4031** in one of the following ways: 4032** 4033** <ul> 4034** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4035** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4036** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4037** </ul> 4038** 4039** In other words, you should call sqlite3_column_text(), 4040** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4041** into the desired format, then invoke sqlite3_column_bytes() or 4042** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4043** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4044** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4045** with calls to sqlite3_column_bytes(). 4046** 4047** ^The pointers returned are valid until a type conversion occurs as 4048** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4049** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4050** and BLOBs is freed automatically. Do <em>not</em> pass the pointers returned 4051** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4052** [sqlite3_free()]. 4053** 4054** ^(If a memory allocation error occurs during the evaluation of any 4055** of these routines, a default value is returned. The default value 4056** is either the integer 0, the floating point number 0.0, or a NULL 4057** pointer. Subsequent calls to [sqlite3_errcode()] will return 4058** [SQLITE_NOMEM].)^ 4059*/ 4060SQLITE_API const void *SQLITE_STDCALL sqlite3_column_blob(sqlite3_stmt*, int iCol); 4061SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4062SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4063SQLITE_API double SQLITE_STDCALL sqlite3_column_double(sqlite3_stmt*, int iCol); 4064SQLITE_API int SQLITE_STDCALL sqlite3_column_int(sqlite3_stmt*, int iCol); 4065SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_column_int64(sqlite3_stmt*, int iCol); 4066SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_column_text(sqlite3_stmt*, int iCol); 4067SQLITE_API const void *SQLITE_STDCALL sqlite3_column_text16(sqlite3_stmt*, int iCol); 4068SQLITE_API int SQLITE_STDCALL sqlite3_column_type(sqlite3_stmt*, int iCol); 4069SQLITE_API sqlite3_value *SQLITE_STDCALL sqlite3_column_value(sqlite3_stmt*, int iCol); 4070 4071/* 4072** CAPI3REF: Destroy A Prepared Statement Object 4073** DESTRUCTOR: sqlite3_stmt 4074** 4075** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4076** ^If the most recent evaluation of the statement encountered no errors 4077** or if the statement is never been evaluated, then sqlite3_finalize() returns 4078** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4079** sqlite3_finalize(S) returns the appropriate [error code] or 4080** [extended error code]. 4081** 4082** ^The sqlite3_finalize(S) routine can be called at any point during 4083** the life cycle of [prepared statement] S: 4084** before statement S is ever evaluated, after 4085** one or more calls to [sqlite3_reset()], or after any call 4086** to [sqlite3_step()] regardless of whether or not the statement has 4087** completed execution. 4088** 4089** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4090** 4091** The application must finalize every [prepared statement] in order to avoid 4092** resource leaks. It is a grievous error for the application to try to use 4093** a prepared statement after it has been finalized. Any use of a prepared 4094** statement after it has been finalized can result in undefined and 4095** undesirable behavior such as segfaults and heap corruption. 4096*/ 4097SQLITE_API int SQLITE_STDCALL sqlite3_finalize(sqlite3_stmt *pStmt); 4098 4099/* 4100** CAPI3REF: Reset A Prepared Statement Object 4101** METHOD: sqlite3_stmt 4102** 4103** The sqlite3_reset() function is called to reset a [prepared statement] 4104** object back to its initial state, ready to be re-executed. 4105** ^Any SQL statement variables that had values bound to them using 4106** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4107** Use [sqlite3_clear_bindings()] to reset the bindings. 4108** 4109** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4110** back to the beginning of its program. 4111** 4112** ^If the most recent call to [sqlite3_step(S)] for the 4113** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4114** or if [sqlite3_step(S)] has never before been called on S, 4115** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4116** 4117** ^If the most recent call to [sqlite3_step(S)] for the 4118** [prepared statement] S indicated an error, then 4119** [sqlite3_reset(S)] returns an appropriate [error code]. 4120** 4121** ^The [sqlite3_reset(S)] interface does not change the values 4122** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4123*/ 4124SQLITE_API int SQLITE_STDCALL sqlite3_reset(sqlite3_stmt *pStmt); 4125 4126/* 4127** CAPI3REF: Create Or Redefine SQL Functions 4128** KEYWORDS: {function creation routines} 4129** KEYWORDS: {application-defined SQL function} 4130** KEYWORDS: {application-defined SQL functions} 4131** METHOD: sqlite3 4132** 4133** ^These functions (collectively known as "function creation routines") 4134** are used to add SQL functions or aggregates or to redefine the behavior 4135** of existing SQL functions or aggregates. The only differences between 4136** these routines are the text encoding expected for 4137** the second parameter (the name of the function being created) 4138** and the presence or absence of a destructor callback for 4139** the application data pointer. 4140** 4141** ^The first parameter is the [database connection] to which the SQL 4142** function is to be added. ^If an application uses more than one database 4143** connection then application-defined SQL functions must be added 4144** to each database connection separately. 4145** 4146** ^The second parameter is the name of the SQL function to be created or 4147** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4148** representation, exclusive of the zero-terminator. ^Note that the name 4149** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4150** ^Any attempt to create a function with a longer name 4151** will result in [SQLITE_MISUSE] being returned. 4152** 4153** ^The third parameter (nArg) 4154** is the number of arguments that the SQL function or 4155** aggregate takes. ^If this parameter is -1, then the SQL function or 4156** aggregate may take any number of arguments between 0 and the limit 4157** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4158** parameter is less than -1 or greater than 127 then the behavior is 4159** undefined. 4160** 4161** ^The fourth parameter, eTextRep, specifies what 4162** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4163** its parameters. The application should set this parameter to 4164** [SQLITE_UTF16LE] if the function implementation invokes 4165** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4166** implementation invokes [sqlite3_value_text16be()] on an input, or 4167** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4168** otherwise. ^The same SQL function may be registered multiple times using 4169** different preferred text encodings, with different implementations for 4170** each encoding. 4171** ^When multiple implementations of the same function are available, SQLite 4172** will pick the one that involves the least amount of data conversion. 4173** 4174** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4175** to signal that the function will always return the same result given 4176** the same inputs within a single SQL statement. Most SQL functions are 4177** deterministic. The built-in [random()] SQL function is an example of a 4178** function that is not deterministic. The SQLite query planner is able to 4179** perform additional optimizations on deterministic functions, so use 4180** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4181** 4182** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4183** function can gain access to this pointer using [sqlite3_user_data()].)^ 4184** 4185** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4186** pointers to C-language functions that implement the SQL function or 4187** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4188** callback only; NULL pointers must be passed as the xStep and xFinal 4189** parameters. ^An aggregate SQL function requires an implementation of xStep 4190** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4191** SQL function or aggregate, pass NULL pointers for all three function 4192** callbacks. 4193** 4194** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4195** then it is destructor for the application data pointer. 4196** The destructor is invoked when the function is deleted, either by being 4197** overloaded or when the database connection closes.)^ 4198** ^The destructor is also invoked if the call to 4199** sqlite3_create_function_v2() fails. 4200** ^When the destructor callback of the tenth parameter is invoked, it 4201** is passed a single argument which is a copy of the application data 4202** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4203** 4204** ^It is permitted to register multiple implementations of the same 4205** functions with the same name but with either differing numbers of 4206** arguments or differing preferred text encodings. ^SQLite will use 4207** the implementation that most closely matches the way in which the 4208** SQL function is used. ^A function implementation with a non-negative 4209** nArg parameter is a better match than a function implementation with 4210** a negative nArg. ^A function where the preferred text encoding 4211** matches the database encoding is a better 4212** match than a function where the encoding is different. 4213** ^A function where the encoding difference is between UTF16le and UTF16be 4214** is a closer match than a function where the encoding difference is 4215** between UTF8 and UTF16. 4216** 4217** ^Built-in functions may be overloaded by new application-defined functions. 4218** 4219** ^An application-defined function is permitted to call other 4220** SQLite interfaces. However, such calls must not 4221** close the database connection nor finalize or reset the prepared 4222** statement in which the function is running. 4223*/ 4224SQLITE_API int SQLITE_STDCALL sqlite3_create_function( 4225 sqlite3 *db, 4226 const char *zFunctionName, 4227 int nArg, 4228 int eTextRep, 4229 void *pApp, 4230 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4231 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4232 void (*xFinal)(sqlite3_context*) 4233); 4234SQLITE_API int SQLITE_STDCALL sqlite3_create_function16( 4235 sqlite3 *db, 4236 const void *zFunctionName, 4237 int nArg, 4238 int eTextRep, 4239 void *pApp, 4240 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4241 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4242 void (*xFinal)(sqlite3_context*) 4243); 4244SQLITE_API int SQLITE_STDCALL sqlite3_create_function_v2( 4245 sqlite3 *db, 4246 const char *zFunctionName, 4247 int nArg, 4248 int eTextRep, 4249 void *pApp, 4250 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4251 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4252 void (*xFinal)(sqlite3_context*), 4253 void(*xDestroy)(void*) 4254); 4255 4256/* 4257** CAPI3REF: Text Encodings 4258** 4259** These constant define integer codes that represent the various 4260** text encodings supported by SQLite. 4261*/ 4262#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4263#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4264#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4265#define SQLITE_UTF16 4 /* Use native byte order */ 4266#define SQLITE_ANY 5 /* Deprecated */ 4267#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4268 4269/* 4270** CAPI3REF: Function Flags 4271** 4272** These constants may be ORed together with the 4273** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4274** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4275** [sqlite3_create_function_v2()]. 4276*/ 4277#define SQLITE_DETERMINISTIC 0x800 4278 4279/* 4280** CAPI3REF: Deprecated Functions 4281** DEPRECATED 4282** 4283** These functions are [deprecated]. In order to maintain 4284** backwards compatibility with older code, these functions continue 4285** to be supported. However, new applications should avoid 4286** the use of these functions. To encourage programmers to avoid 4287** these functions, we will not explain what they do. 4288*/ 4289#ifndef SQLITE_OMIT_DEPRECATED 4290SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_aggregate_count(sqlite3_context*); 4291SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_expired(sqlite3_stmt*); 4292SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4293SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_global_recover(void); 4294SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_thread_cleanup(void); 4295SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4296 void*,sqlite3_int64); 4297#endif 4298 4299/* 4300** CAPI3REF: Obtaining SQL Values 4301** METHOD: sqlite3_value 4302** 4303** The C-language implementation of SQL functions and aggregates uses 4304** this set of interface routines to access the parameter values on 4305** the function or aggregate. 4306** 4307** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4308** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4309** define callbacks that implement the SQL functions and aggregates. 4310** The 3rd parameter to these callbacks is an array of pointers to 4311** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4312** each parameter to the SQL function. These routines are used to 4313** extract values from the [sqlite3_value] objects. 4314** 4315** These routines work only with [protected sqlite3_value] objects. 4316** Any attempt to use these routines on an [unprotected sqlite3_value] 4317** object results in undefined behavior. 4318** 4319** ^These routines work just like the corresponding [column access functions] 4320** except that these routines take a single [protected sqlite3_value] object 4321** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4322** 4323** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4324** in the native byte-order of the host machine. ^The 4325** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4326** extract UTF-16 strings as big-endian and little-endian respectively. 4327** 4328** ^(The sqlite3_value_numeric_type() interface attempts to apply 4329** numeric affinity to the value. This means that an attempt is 4330** made to convert the value to an integer or floating point. If 4331** such a conversion is possible without loss of information (in other 4332** words, if the value is a string that looks like a number) 4333** then the conversion is performed. Otherwise no conversion occurs. 4334** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4335** 4336** Please pay particular attention to the fact that the pointer returned 4337** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4338** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4339** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4340** or [sqlite3_value_text16()]. 4341** 4342** These routines must be called from the same thread as 4343** the SQL function that supplied the [sqlite3_value*] parameters. 4344*/ 4345SQLITE_API const void *SQLITE_STDCALL sqlite3_value_blob(sqlite3_value*); 4346SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes(sqlite3_value*); 4347SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes16(sqlite3_value*); 4348SQLITE_API double SQLITE_STDCALL sqlite3_value_double(sqlite3_value*); 4349SQLITE_API int SQLITE_STDCALL sqlite3_value_int(sqlite3_value*); 4350SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_value_int64(sqlite3_value*); 4351SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_value_text(sqlite3_value*); 4352SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16(sqlite3_value*); 4353SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16le(sqlite3_value*); 4354SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16be(sqlite3_value*); 4355SQLITE_API int SQLITE_STDCALL sqlite3_value_type(sqlite3_value*); 4356SQLITE_API int SQLITE_STDCALL sqlite3_value_numeric_type(sqlite3_value*); 4357 4358/* 4359** CAPI3REF: Copy And Free SQL Values 4360** METHOD: sqlite3_value 4361** 4362** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4363** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4364** is a [protected sqlite3_value] object even if the input is not. 4365** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4366** memory allocation fails. 4367** 4368** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4369** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4370** then sqlite3_value_free(V) is a harmless no-op. 4371*/ 4372SQLITE_API SQLITE_EXPERIMENTAL sqlite3_value *SQLITE_STDCALL sqlite3_value_dup(const sqlite3_value*); 4373SQLITE_API SQLITE_EXPERIMENTAL void SQLITE_STDCALL sqlite3_value_free(sqlite3_value*); 4374 4375/* 4376** CAPI3REF: Obtain Aggregate Function Context 4377** METHOD: sqlite3_context 4378** 4379** Implementations of aggregate SQL functions use this 4380** routine to allocate memory for storing their state. 4381** 4382** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4383** for a particular aggregate function, SQLite 4384** allocates N of memory, zeroes out that memory, and returns a pointer 4385** to the new memory. ^On second and subsequent calls to 4386** sqlite3_aggregate_context() for the same aggregate function instance, 4387** the same buffer is returned. Sqlite3_aggregate_context() is normally 4388** called once for each invocation of the xStep callback and then one 4389** last time when the xFinal callback is invoked. ^(When no rows match 4390** an aggregate query, the xStep() callback of the aggregate function 4391** implementation is never called and xFinal() is called exactly once. 4392** In those cases, sqlite3_aggregate_context() might be called for the 4393** first time from within xFinal().)^ 4394** 4395** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4396** when first called if N is less than or equal to zero or if a memory 4397** allocate error occurs. 4398** 4399** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4400** determined by the N parameter on first successful call. Changing the 4401** value of N in subsequent call to sqlite3_aggregate_context() within 4402** the same aggregate function instance will not resize the memory 4403** allocation.)^ Within the xFinal callback, it is customary to set 4404** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4405** pointless memory allocations occur. 4406** 4407** ^SQLite automatically frees the memory allocated by 4408** sqlite3_aggregate_context() when the aggregate query concludes. 4409** 4410** The first parameter must be a copy of the 4411** [sqlite3_context | SQL function context] that is the first parameter 4412** to the xStep or xFinal callback routine that implements the aggregate 4413** function. 4414** 4415** This routine must be called from the same thread in which 4416** the aggregate SQL function is running. 4417*/ 4418SQLITE_API void *SQLITE_STDCALL sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4419 4420/* 4421** CAPI3REF: User Data For Functions 4422** METHOD: sqlite3_context 4423** 4424** ^The sqlite3_user_data() interface returns a copy of 4425** the pointer that was the pUserData parameter (the 5th parameter) 4426** of the [sqlite3_create_function()] 4427** and [sqlite3_create_function16()] routines that originally 4428** registered the application defined function. 4429** 4430** This routine must be called from the same thread in which 4431** the application-defined function is running. 4432*/ 4433SQLITE_API void *SQLITE_STDCALL sqlite3_user_data(sqlite3_context*); 4434 4435/* 4436** CAPI3REF: Database Connection For Functions 4437** METHOD: sqlite3_context 4438** 4439** ^The sqlite3_context_db_handle() interface returns a copy of 4440** the pointer to the [database connection] (the 1st parameter) 4441** of the [sqlite3_create_function()] 4442** and [sqlite3_create_function16()] routines that originally 4443** registered the application defined function. 4444*/ 4445SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_context_db_handle(sqlite3_context*); 4446 4447/* 4448** CAPI3REF: Function Auxiliary Data 4449** METHOD: sqlite3_context 4450** 4451** These functions may be used by (non-aggregate) SQL functions to 4452** associate metadata with argument values. If the same value is passed to 4453** multiple invocations of the same SQL function during query execution, under 4454** some circumstances the associated metadata may be preserved. An example 4455** of where this might be useful is in a regular-expression matching 4456** function. The compiled version of the regular expression can be stored as 4457** metadata associated with the pattern string. 4458** Then as long as the pattern string remains the same, 4459** the compiled regular expression can be reused on multiple 4460** invocations of the same function. 4461** 4462** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4463** associated by the sqlite3_set_auxdata() function with the Nth argument 4464** value to the application-defined function. ^If there is no metadata 4465** associated with the function argument, this sqlite3_get_auxdata() interface 4466** returns a NULL pointer. 4467** 4468** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4469** argument of the application-defined function. ^Subsequent 4470** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4471** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4472** NULL if the metadata has been discarded. 4473** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4474** SQLite will invoke the destructor function X with parameter P exactly 4475** once, when the metadata is discarded. 4476** SQLite is free to discard the metadata at any time, including: <ul> 4477** <li> when the corresponding function parameter changes, or 4478** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4479** SQL statement, or 4480** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or 4481** <li> during the original sqlite3_set_auxdata() call when a memory 4482** allocation error occurs. </ul>)^ 4483** 4484** Note the last bullet in particular. The destructor X in 4485** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4486** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4487** should be called near the end of the function implementation and the 4488** function implementation should not make any use of P after 4489** sqlite3_set_auxdata() has been called. 4490** 4491** ^(In practice, metadata is preserved between function calls for 4492** function parameters that are compile-time constants, including literal 4493** values and [parameters] and expressions composed from the same.)^ 4494** 4495** These routines must be called from the same thread in which 4496** the SQL function is running. 4497*/ 4498SQLITE_API void *SQLITE_STDCALL sqlite3_get_auxdata(sqlite3_context*, int N); 4499SQLITE_API void SQLITE_STDCALL sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4500 4501 4502/* 4503** CAPI3REF: Constants Defining Special Destructor Behavior 4504** 4505** These are special values for the destructor that is passed in as the 4506** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4507** argument is SQLITE_STATIC, it means that the content pointer is constant 4508** and will never change. It does not need to be destroyed. ^The 4509** SQLITE_TRANSIENT value means that the content will likely change in 4510** the near future and that SQLite should make its own private copy of 4511** the content before returning. 4512** 4513** The typedef is necessary to work around problems in certain 4514** C++ compilers. 4515*/ 4516typedef void (*sqlite3_destructor_type)(void*); 4517#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4518#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4519 4520/* 4521** CAPI3REF: Setting The Result Of An SQL Function 4522** METHOD: sqlite3_context 4523** 4524** These routines are used by the xFunc or xFinal callbacks that 4525** implement SQL functions and aggregates. See 4526** [sqlite3_create_function()] and [sqlite3_create_function16()] 4527** for additional information. 4528** 4529** These functions work very much like the [parameter binding] family of 4530** functions used to bind values to host parameters in prepared statements. 4531** Refer to the [SQL parameter] documentation for additional information. 4532** 4533** ^The sqlite3_result_blob() interface sets the result from 4534** an application-defined function to be the BLOB whose content is pointed 4535** to by the second parameter and which is N bytes long where N is the 4536** third parameter. 4537** 4538** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 4539** interfaces set the result of the application-defined function to be 4540** a BLOB containing all zero bytes and N bytes in size. 4541** 4542** ^The sqlite3_result_double() interface sets the result from 4543** an application-defined function to be a floating point value specified 4544** by its 2nd argument. 4545** 4546** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4547** cause the implemented SQL function to throw an exception. 4548** ^SQLite uses the string pointed to by the 4549** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4550** as the text of an error message. ^SQLite interprets the error 4551** message string from sqlite3_result_error() as UTF-8. ^SQLite 4552** interprets the string from sqlite3_result_error16() as UTF-16 in native 4553** byte order. ^If the third parameter to sqlite3_result_error() 4554** or sqlite3_result_error16() is negative then SQLite takes as the error 4555** message all text up through the first zero character. 4556** ^If the third parameter to sqlite3_result_error() or 4557** sqlite3_result_error16() is non-negative then SQLite takes that many 4558** bytes (not characters) from the 2nd parameter as the error message. 4559** ^The sqlite3_result_error() and sqlite3_result_error16() 4560** routines make a private copy of the error message text before 4561** they return. Hence, the calling function can deallocate or 4562** modify the text after they return without harm. 4563** ^The sqlite3_result_error_code() function changes the error code 4564** returned by SQLite as a result of an error in a function. ^By default, 4565** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4566** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4567** 4568** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4569** error indicating that a string or BLOB is too long to represent. 4570** 4571** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4572** error indicating that a memory allocation failed. 4573** 4574** ^The sqlite3_result_int() interface sets the return value 4575** of the application-defined function to be the 32-bit signed integer 4576** value given in the 2nd argument. 4577** ^The sqlite3_result_int64() interface sets the return value 4578** of the application-defined function to be the 64-bit signed integer 4579** value given in the 2nd argument. 4580** 4581** ^The sqlite3_result_null() interface sets the return value 4582** of the application-defined function to be NULL. 4583** 4584** ^The sqlite3_result_text(), sqlite3_result_text16(), 4585** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4586** set the return value of the application-defined function to be 4587** a text string which is represented as UTF-8, UTF-16 native byte order, 4588** UTF-16 little endian, or UTF-16 big endian, respectively. 4589** ^The sqlite3_result_text64() interface sets the return value of an 4590** application-defined function to be a text string in an encoding 4591** specified by the fifth (and last) parameter, which must be one 4592** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 4593** ^SQLite takes the text result from the application from 4594** the 2nd parameter of the sqlite3_result_text* interfaces. 4595** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4596** is negative, then SQLite takes result text from the 2nd parameter 4597** through the first zero character. 4598** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4599** is non-negative, then as many bytes (not characters) of the text 4600** pointed to by the 2nd parameter are taken as the application-defined 4601** function result. If the 3rd parameter is non-negative, then it 4602** must be the byte offset into the string where the NUL terminator would 4603** appear if the string where NUL terminated. If any NUL characters occur 4604** in the string at a byte offset that is less than the value of the 3rd 4605** parameter, then the resulting string will contain embedded NULs and the 4606** result of expressions operating on strings with embedded NULs is undefined. 4607** ^If the 4th parameter to the sqlite3_result_text* interfaces 4608** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4609** function as the destructor on the text or BLOB result when it has 4610** finished using that result. 4611** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4612** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4613** assumes that the text or BLOB result is in constant space and does not 4614** copy the content of the parameter nor call a destructor on the content 4615** when it has finished using that result. 4616** ^If the 4th parameter to the sqlite3_result_text* interfaces 4617** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4618** then SQLite makes a copy of the result into space obtained from 4619** from [sqlite3_malloc()] before it returns. 4620** 4621** ^The sqlite3_result_value() interface sets the result of 4622** the application-defined function to be a copy of the 4623** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4624** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4625** so that the [sqlite3_value] specified in the parameter may change or 4626** be deallocated after sqlite3_result_value() returns without harm. 4627** ^A [protected sqlite3_value] object may always be used where an 4628** [unprotected sqlite3_value] object is required, so either 4629** kind of [sqlite3_value] object can be used with this interface. 4630** 4631** If these routines are called from within the different thread 4632** than the one containing the application-defined function that received 4633** the [sqlite3_context] pointer, the results are undefined. 4634*/ 4635SQLITE_API void SQLITE_STDCALL sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4636SQLITE_API void SQLITE_STDCALL sqlite3_result_blob64(sqlite3_context*,const void*, 4637 sqlite3_uint64,void(*)(void*)); 4638SQLITE_API void SQLITE_STDCALL sqlite3_result_double(sqlite3_context*, double); 4639SQLITE_API void SQLITE_STDCALL sqlite3_result_error(sqlite3_context*, const char*, int); 4640SQLITE_API void SQLITE_STDCALL sqlite3_result_error16(sqlite3_context*, const void*, int); 4641SQLITE_API void SQLITE_STDCALL sqlite3_result_error_toobig(sqlite3_context*); 4642SQLITE_API void SQLITE_STDCALL sqlite3_result_error_nomem(sqlite3_context*); 4643SQLITE_API void SQLITE_STDCALL sqlite3_result_error_code(sqlite3_context*, int); 4644SQLITE_API void SQLITE_STDCALL sqlite3_result_int(sqlite3_context*, int); 4645SQLITE_API void SQLITE_STDCALL sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4646SQLITE_API void SQLITE_STDCALL sqlite3_result_null(sqlite3_context*); 4647SQLITE_API void SQLITE_STDCALL sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4648SQLITE_API void SQLITE_STDCALL sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 4649 void(*)(void*), unsigned char encoding); 4650SQLITE_API void SQLITE_STDCALL sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4651SQLITE_API void SQLITE_STDCALL sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4652SQLITE_API void SQLITE_STDCALL sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4653SQLITE_API void SQLITE_STDCALL sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4654SQLITE_API void SQLITE_STDCALL sqlite3_result_zeroblob(sqlite3_context*, int n); 4655SQLITE_API int SQLITE_STDCALL sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 4656 4657/* 4658** CAPI3REF: Define New Collating Sequences 4659** METHOD: sqlite3 4660** 4661** ^These functions add, remove, or modify a [collation] associated 4662** with the [database connection] specified as the first argument. 4663** 4664** ^The name of the collation is a UTF-8 string 4665** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4666** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4667** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4668** considered to be the same name. 4669** 4670** ^(The third argument (eTextRep) must be one of the constants: 4671** <ul> 4672** <li> [SQLITE_UTF8], 4673** <li> [SQLITE_UTF16LE], 4674** <li> [SQLITE_UTF16BE], 4675** <li> [SQLITE_UTF16], or 4676** <li> [SQLITE_UTF16_ALIGNED]. 4677** </ul>)^ 4678** ^The eTextRep argument determines the encoding of strings passed 4679** to the collating function callback, xCallback. 4680** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4681** force strings to be UTF16 with native byte order. 4682** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4683** on an even byte address. 4684** 4685** ^The fourth argument, pArg, is an application data pointer that is passed 4686** through as the first argument to the collating function callback. 4687** 4688** ^The fifth argument, xCallback, is a pointer to the collating function. 4689** ^Multiple collating functions can be registered using the same name but 4690** with different eTextRep parameters and SQLite will use whichever 4691** function requires the least amount of data transformation. 4692** ^If the xCallback argument is NULL then the collating function is 4693** deleted. ^When all collating functions having the same name are deleted, 4694** that collation is no longer usable. 4695** 4696** ^The collating function callback is invoked with a copy of the pArg 4697** application data pointer and with two strings in the encoding specified 4698** by the eTextRep argument. The collating function must return an 4699** integer that is negative, zero, or positive 4700** if the first string is less than, equal to, or greater than the second, 4701** respectively. A collating function must always return the same answer 4702** given the same inputs. If two or more collating functions are registered 4703** to the same collation name (using different eTextRep values) then all 4704** must give an equivalent answer when invoked with equivalent strings. 4705** The collating function must obey the following properties for all 4706** strings A, B, and C: 4707** 4708** <ol> 4709** <li> If A==B then B==A. 4710** <li> If A==B and B==C then A==C. 4711** <li> If A<B THEN B>A. 4712** <li> If A<B and B<C then A<C. 4713** </ol> 4714** 4715** If a collating function fails any of the above constraints and that 4716** collating function is registered and used, then the behavior of SQLite 4717** is undefined. 4718** 4719** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4720** with the addition that the xDestroy callback is invoked on pArg when 4721** the collating function is deleted. 4722** ^Collating functions are deleted when they are overridden by later 4723** calls to the collation creation functions or when the 4724** [database connection] is closed using [sqlite3_close()]. 4725** 4726** ^The xDestroy callback is <u>not</u> called if the 4727** sqlite3_create_collation_v2() function fails. Applications that invoke 4728** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4729** check the return code and dispose of the application data pointer 4730** themselves rather than expecting SQLite to deal with it for them. 4731** This is different from every other SQLite interface. The inconsistency 4732** is unfortunate but cannot be changed without breaking backwards 4733** compatibility. 4734** 4735** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4736*/ 4737SQLITE_API int SQLITE_STDCALL sqlite3_create_collation( 4738 sqlite3*, 4739 const char *zName, 4740 int eTextRep, 4741 void *pArg, 4742 int(*xCompare)(void*,int,const void*,int,const void*) 4743); 4744SQLITE_API int SQLITE_STDCALL sqlite3_create_collation_v2( 4745 sqlite3*, 4746 const char *zName, 4747 int eTextRep, 4748 void *pArg, 4749 int(*xCompare)(void*,int,const void*,int,const void*), 4750 void(*xDestroy)(void*) 4751); 4752SQLITE_API int SQLITE_STDCALL sqlite3_create_collation16( 4753 sqlite3*, 4754 const void *zName, 4755 int eTextRep, 4756 void *pArg, 4757 int(*xCompare)(void*,int,const void*,int,const void*) 4758); 4759 4760/* 4761** CAPI3REF: Collation Needed Callbacks 4762** METHOD: sqlite3 4763** 4764** ^To avoid having to register all collation sequences before a database 4765** can be used, a single callback function may be registered with the 4766** [database connection] to be invoked whenever an undefined collation 4767** sequence is required. 4768** 4769** ^If the function is registered using the sqlite3_collation_needed() API, 4770** then it is passed the names of undefined collation sequences as strings 4771** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4772** the names are passed as UTF-16 in machine native byte order. 4773** ^A call to either function replaces the existing collation-needed callback. 4774** 4775** ^(When the callback is invoked, the first argument passed is a copy 4776** of the second argument to sqlite3_collation_needed() or 4777** sqlite3_collation_needed16(). The second argument is the database 4778** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4779** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4780** sequence function required. The fourth parameter is the name of the 4781** required collation sequence.)^ 4782** 4783** The callback function should register the desired collation using 4784** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4785** [sqlite3_create_collation_v2()]. 4786*/ 4787SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed( 4788 sqlite3*, 4789 void*, 4790 void(*)(void*,sqlite3*,int eTextRep,const char*) 4791); 4792SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed16( 4793 sqlite3*, 4794 void*, 4795 void(*)(void*,sqlite3*,int eTextRep,const void*) 4796); 4797 4798#ifdef SQLITE_HAS_CODEC 4799/* 4800** Specify the key for an encrypted database. This routine should be 4801** called right after sqlite3_open(). 4802** 4803** The code to implement this API is not available in the public release 4804** of SQLite. 4805*/ 4806SQLITE_API int SQLITE_STDCALL sqlite3_key( 4807 sqlite3 *db, /* Database to be rekeyed */ 4808 const void *pKey, int nKey /* The key */ 4809); 4810SQLITE_API int SQLITE_STDCALL sqlite3_key_v2( 4811 sqlite3 *db, /* Database to be rekeyed */ 4812 const char *zDbName, /* Name of the database */ 4813 const void *pKey, int nKey /* The key */ 4814); 4815 4816/* 4817** Change the key on an open database. If the current database is not 4818** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4819** database is decrypted. 4820** 4821** The code to implement this API is not available in the public release 4822** of SQLite. 4823*/ 4824SQLITE_API int SQLITE_STDCALL sqlite3_rekey( 4825 sqlite3 *db, /* Database to be rekeyed */ 4826 const void *pKey, int nKey /* The new key */ 4827); 4828SQLITE_API int SQLITE_STDCALL sqlite3_rekey_v2( 4829 sqlite3 *db, /* Database to be rekeyed */ 4830 const char *zDbName, /* Name of the database */ 4831 const void *pKey, int nKey /* The new key */ 4832); 4833 4834/* 4835** Specify the activation key for a SEE database. Unless 4836** activated, none of the SEE routines will work. 4837*/ 4838SQLITE_API void SQLITE_STDCALL sqlite3_activate_see( 4839 const char *zPassPhrase /* Activation phrase */ 4840); 4841#endif 4842 4843#ifdef SQLITE_ENABLE_CEROD 4844/* 4845** Specify the activation key for a CEROD database. Unless 4846** activated, none of the CEROD routines will work. 4847*/ 4848SQLITE_API void SQLITE_STDCALL sqlite3_activate_cerod( 4849 const char *zPassPhrase /* Activation phrase */ 4850); 4851#endif 4852 4853/* 4854** CAPI3REF: Suspend Execution For A Short Time 4855** 4856** The sqlite3_sleep() function causes the current thread to suspend execution 4857** for at least a number of milliseconds specified in its parameter. 4858** 4859** If the operating system does not support sleep requests with 4860** millisecond time resolution, then the time will be rounded up to 4861** the nearest second. The number of milliseconds of sleep actually 4862** requested from the operating system is returned. 4863** 4864** ^SQLite implements this interface by calling the xSleep() 4865** method of the default [sqlite3_vfs] object. If the xSleep() method 4866** of the default VFS is not implemented correctly, or not implemented at 4867** all, then the behavior of sqlite3_sleep() may deviate from the description 4868** in the previous paragraphs. 4869*/ 4870SQLITE_API int SQLITE_STDCALL sqlite3_sleep(int); 4871 4872/* 4873** CAPI3REF: Name Of The Folder Holding Temporary Files 4874** 4875** ^(If this global variable is made to point to a string which is 4876** the name of a folder (a.k.a. directory), then all temporary files 4877** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4878** will be placed in that directory.)^ ^If this variable 4879** is a NULL pointer, then SQLite performs a search for an appropriate 4880** temporary file directory. 4881** 4882** Applications are strongly discouraged from using this global variable. 4883** It is required to set a temporary folder on Windows Runtime (WinRT). 4884** But for all other platforms, it is highly recommended that applications 4885** neither read nor write this variable. This global variable is a relic 4886** that exists for backwards compatibility of legacy applications and should 4887** be avoided in new projects. 4888** 4889** It is not safe to read or modify this variable in more than one 4890** thread at a time. It is not safe to read or modify this variable 4891** if a [database connection] is being used at the same time in a separate 4892** thread. 4893** It is intended that this variable be set once 4894** as part of process initialization and before any SQLite interface 4895** routines have been called and that this variable remain unchanged 4896** thereafter. 4897** 4898** ^The [temp_store_directory pragma] may modify this variable and cause 4899** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4900** the [temp_store_directory pragma] always assumes that any string 4901** that this variable points to is held in memory obtained from 4902** [sqlite3_malloc] and the pragma may attempt to free that memory 4903** using [sqlite3_free]. 4904** Hence, if this variable is modified directly, either it should be 4905** made NULL or made to point to memory obtained from [sqlite3_malloc] 4906** or else the use of the [temp_store_directory pragma] should be avoided. 4907** Except when requested by the [temp_store_directory pragma], SQLite 4908** does not free the memory that sqlite3_temp_directory points to. If 4909** the application wants that memory to be freed, it must do 4910** so itself, taking care to only do so after all [database connection] 4911** objects have been destroyed. 4912** 4913** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4914** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4915** features that require the use of temporary files may fail. Here is an 4916** example of how to do this using C++ with the Windows Runtime: 4917** 4918** <blockquote><pre> 4919** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4920** TemporaryFolder->Path->Data(); 4921** char zPathBuf[MAX_PATH + 1]; 4922** memset(zPathBuf, 0, sizeof(zPathBuf)); 4923** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4924** NULL, NULL); 4925** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4926** </pre></blockquote> 4927*/ 4928SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 4929 4930/* 4931** CAPI3REF: Name Of The Folder Holding Database Files 4932** 4933** ^(If this global variable is made to point to a string which is 4934** the name of a folder (a.k.a. directory), then all database files 4935** specified with a relative pathname and created or accessed by 4936** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4937** to be relative to that directory.)^ ^If this variable is a NULL 4938** pointer, then SQLite assumes that all database files specified 4939** with a relative pathname are relative to the current directory 4940** for the process. Only the windows VFS makes use of this global 4941** variable; it is ignored by the unix VFS. 4942** 4943** Changing the value of this variable while a database connection is 4944** open can result in a corrupt database. 4945** 4946** It is not safe to read or modify this variable in more than one 4947** thread at a time. It is not safe to read or modify this variable 4948** if a [database connection] is being used at the same time in a separate 4949** thread. 4950** It is intended that this variable be set once 4951** as part of process initialization and before any SQLite interface 4952** routines have been called and that this variable remain unchanged 4953** thereafter. 4954** 4955** ^The [data_store_directory pragma] may modify this variable and cause 4956** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4957** the [data_store_directory pragma] always assumes that any string 4958** that this variable points to is held in memory obtained from 4959** [sqlite3_malloc] and the pragma may attempt to free that memory 4960** using [sqlite3_free]. 4961** Hence, if this variable is modified directly, either it should be 4962** made NULL or made to point to memory obtained from [sqlite3_malloc] 4963** or else the use of the [data_store_directory pragma] should be avoided. 4964*/ 4965SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory; 4966 4967/* 4968** CAPI3REF: Test For Auto-Commit Mode 4969** KEYWORDS: {autocommit mode} 4970** METHOD: sqlite3 4971** 4972** ^The sqlite3_get_autocommit() interface returns non-zero or 4973** zero if the given database connection is or is not in autocommit mode, 4974** respectively. ^Autocommit mode is on by default. 4975** ^Autocommit mode is disabled by a [BEGIN] statement. 4976** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4977** 4978** If certain kinds of errors occur on a statement within a multi-statement 4979** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4980** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4981** transaction might be rolled back automatically. The only way to 4982** find out whether SQLite automatically rolled back the transaction after 4983** an error is to use this function. 4984** 4985** If another thread changes the autocommit status of the database 4986** connection while this routine is running, then the return value 4987** is undefined. 4988*/ 4989SQLITE_API int SQLITE_STDCALL sqlite3_get_autocommit(sqlite3*); 4990 4991/* 4992** CAPI3REF: Find The Database Handle Of A Prepared Statement 4993** METHOD: sqlite3_stmt 4994** 4995** ^The sqlite3_db_handle interface returns the [database connection] handle 4996** to which a [prepared statement] belongs. ^The [database connection] 4997** returned by sqlite3_db_handle is the same [database connection] 4998** that was the first argument 4999** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5000** create the statement in the first place. 5001*/ 5002SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_db_handle(sqlite3_stmt*); 5003 5004/* 5005** CAPI3REF: Return The Filename For A Database Connection 5006** METHOD: sqlite3 5007** 5008** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5009** associated with database N of connection D. ^The main database file 5010** has the name "main". If there is no attached database N on the database 5011** connection D, or if database N is a temporary or in-memory database, then 5012** a NULL pointer is returned. 5013** 5014** ^The filename returned by this function is the output of the 5015** xFullPathname method of the [VFS]. ^In other words, the filename 5016** will be an absolute pathname, even if the filename used 5017** to open the database originally was a URI or relative pathname. 5018*/ 5019SQLITE_API const char *SQLITE_STDCALL sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5020 5021/* 5022** CAPI3REF: Determine if a database is read-only 5023** METHOD: sqlite3 5024** 5025** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5026** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5027** the name of a database on connection D. 5028*/ 5029SQLITE_API int SQLITE_STDCALL sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5030 5031/* 5032** CAPI3REF: Find the next prepared statement 5033** METHOD: sqlite3 5034** 5035** ^This interface returns a pointer to the next [prepared statement] after 5036** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5037** then this interface returns a pointer to the first prepared statement 5038** associated with the database connection pDb. ^If no prepared statement 5039** satisfies the conditions of this routine, it returns NULL. 5040** 5041** The [database connection] pointer D in a call to 5042** [sqlite3_next_stmt(D,S)] must refer to an open database 5043** connection and in particular must not be a NULL pointer. 5044*/ 5045SQLITE_API sqlite3_stmt *SQLITE_STDCALL sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5046 5047/* 5048** CAPI3REF: Commit And Rollback Notification Callbacks 5049** METHOD: sqlite3 5050** 5051** ^The sqlite3_commit_hook() interface registers a callback 5052** function to be invoked whenever a transaction is [COMMIT | committed]. 5053** ^Any callback set by a previous call to sqlite3_commit_hook() 5054** for the same database connection is overridden. 5055** ^The sqlite3_rollback_hook() interface registers a callback 5056** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5057** ^Any callback set by a previous call to sqlite3_rollback_hook() 5058** for the same database connection is overridden. 5059** ^The pArg argument is passed through to the callback. 5060** ^If the callback on a commit hook function returns non-zero, 5061** then the commit is converted into a rollback. 5062** 5063** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5064** return the P argument from the previous call of the same function 5065** on the same [database connection] D, or NULL for 5066** the first call for each function on D. 5067** 5068** The commit and rollback hook callbacks are not reentrant. 5069** The callback implementation must not do anything that will modify 5070** the database connection that invoked the callback. Any actions 5071** to modify the database connection must be deferred until after the 5072** completion of the [sqlite3_step()] call that triggered the commit 5073** or rollback hook in the first place. 5074** Note that running any other SQL statements, including SELECT statements, 5075** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5076** the database connections for the meaning of "modify" in this paragraph. 5077** 5078** ^Registering a NULL function disables the callback. 5079** 5080** ^When the commit hook callback routine returns zero, the [COMMIT] 5081** operation is allowed to continue normally. ^If the commit hook 5082** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5083** ^The rollback hook is invoked on a rollback that results from a commit 5084** hook returning non-zero, just as it would be with any other rollback. 5085** 5086** ^For the purposes of this API, a transaction is said to have been 5087** rolled back if an explicit "ROLLBACK" statement is executed, or 5088** an error or constraint causes an implicit rollback to occur. 5089** ^The rollback callback is not invoked if a transaction is 5090** automatically rolled back because the database connection is closed. 5091** 5092** See also the [sqlite3_update_hook()] interface. 5093*/ 5094SQLITE_API void *SQLITE_STDCALL sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5095SQLITE_API void *SQLITE_STDCALL sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5096 5097/* 5098** CAPI3REF: Data Change Notification Callbacks 5099** METHOD: sqlite3 5100** 5101** ^The sqlite3_update_hook() interface registers a callback function 5102** with the [database connection] identified by the first argument 5103** to be invoked whenever a row is updated, inserted or deleted in 5104** a rowid table. 5105** ^Any callback set by a previous call to this function 5106** for the same database connection is overridden. 5107** 5108** ^The second argument is a pointer to the function to invoke when a 5109** row is updated, inserted or deleted in a rowid table. 5110** ^The first argument to the callback is a copy of the third argument 5111** to sqlite3_update_hook(). 5112** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5113** or [SQLITE_UPDATE], depending on the operation that caused the callback 5114** to be invoked. 5115** ^The third and fourth arguments to the callback contain pointers to the 5116** database and table name containing the affected row. 5117** ^The final callback parameter is the [rowid] of the row. 5118** ^In the case of an update, this is the [rowid] after the update takes place. 5119** 5120** ^(The update hook is not invoked when internal system tables are 5121** modified (i.e. sqlite_master and sqlite_sequence).)^ 5122** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5123** 5124** ^In the current implementation, the update hook 5125** is not invoked when duplication rows are deleted because of an 5126** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5127** invoked when rows are deleted using the [truncate optimization]. 5128** The exceptions defined in this paragraph might change in a future 5129** release of SQLite. 5130** 5131** The update hook implementation must not do anything that will modify 5132** the database connection that invoked the update hook. Any actions 5133** to modify the database connection must be deferred until after the 5134** completion of the [sqlite3_step()] call that triggered the update hook. 5135** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5136** database connections for the meaning of "modify" in this paragraph. 5137** 5138** ^The sqlite3_update_hook(D,C,P) function 5139** returns the P argument from the previous call 5140** on the same [database connection] D, or NULL for 5141** the first call on D. 5142** 5143** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 5144** interfaces. 5145*/ 5146SQLITE_API void *SQLITE_STDCALL sqlite3_update_hook( 5147 sqlite3*, 5148 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5149 void* 5150); 5151 5152/* 5153** CAPI3REF: Enable Or Disable Shared Pager Cache 5154** 5155** ^(This routine enables or disables the sharing of the database cache 5156** and schema data structures between [database connection | connections] 5157** to the same database. Sharing is enabled if the argument is true 5158** and disabled if the argument is false.)^ 5159** 5160** ^Cache sharing is enabled and disabled for an entire process. 5161** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 5162** sharing was enabled or disabled for each thread separately. 5163** 5164** ^(The cache sharing mode set by this interface effects all subsequent 5165** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5166** Existing database connections continue use the sharing mode 5167** that was in effect at the time they were opened.)^ 5168** 5169** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5170** successfully. An [error code] is returned otherwise.)^ 5171** 5172** ^Shared cache is disabled by default. But this might change in 5173** future releases of SQLite. Applications that care about shared 5174** cache setting should set it explicitly. 5175** 5176** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5177** and will always return SQLITE_MISUSE. On those systems, 5178** shared cache mode should be enabled per-database connection via 5179** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5180** 5181** This interface is threadsafe on processors where writing a 5182** 32-bit integer is atomic. 5183** 5184** See Also: [SQLite Shared-Cache Mode] 5185*/ 5186SQLITE_API int SQLITE_STDCALL sqlite3_enable_shared_cache(int); 5187 5188/* 5189** CAPI3REF: Attempt To Free Heap Memory 5190** 5191** ^The sqlite3_release_memory() interface attempts to free N bytes 5192** of heap memory by deallocating non-essential memory allocations 5193** held by the database library. Memory used to cache database 5194** pages to improve performance is an example of non-essential memory. 5195** ^sqlite3_release_memory() returns the number of bytes actually freed, 5196** which might be more or less than the amount requested. 5197** ^The sqlite3_release_memory() routine is a no-op returning zero 5198** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5199** 5200** See also: [sqlite3_db_release_memory()] 5201*/ 5202SQLITE_API int SQLITE_STDCALL sqlite3_release_memory(int); 5203 5204/* 5205** CAPI3REF: Free Memory Used By A Database Connection 5206** METHOD: sqlite3 5207** 5208** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5209** memory as possible from database connection D. Unlike the 5210** [sqlite3_release_memory()] interface, this interface is in effect even 5211** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5212** omitted. 5213** 5214** See also: [sqlite3_release_memory()] 5215*/ 5216SQLITE_API int SQLITE_STDCALL sqlite3_db_release_memory(sqlite3*); 5217 5218/* 5219** CAPI3REF: Impose A Limit On Heap Size 5220** 5221** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5222** soft limit on the amount of heap memory that may be allocated by SQLite. 5223** ^SQLite strives to keep heap memory utilization below the soft heap 5224** limit by reducing the number of pages held in the page cache 5225** as heap memory usages approaches the limit. 5226** ^The soft heap limit is "soft" because even though SQLite strives to stay 5227** below the limit, it will exceed the limit rather than generate 5228** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5229** is advisory only. 5230** 5231** ^The return value from sqlite3_soft_heap_limit64() is the size of 5232** the soft heap limit prior to the call, or negative in the case of an 5233** error. ^If the argument N is negative 5234** then no change is made to the soft heap limit. Hence, the current 5235** size of the soft heap limit can be determined by invoking 5236** sqlite3_soft_heap_limit64() with a negative argument. 5237** 5238** ^If the argument N is zero then the soft heap limit is disabled. 5239** 5240** ^(The soft heap limit is not enforced in the current implementation 5241** if one or more of following conditions are true: 5242** 5243** <ul> 5244** <li> The soft heap limit is set to zero. 5245** <li> Memory accounting is disabled using a combination of the 5246** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5247** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5248** <li> An alternative page cache implementation is specified using 5249** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5250** <li> The page cache allocates from its own memory pool supplied 5251** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5252** from the heap. 5253** </ul>)^ 5254** 5255** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 5256** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5257** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5258** the soft heap limit is enforced on every memory allocation. Without 5259** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5260** when memory is allocated by the page cache. Testing suggests that because 5261** the page cache is the predominate memory user in SQLite, most 5262** applications will achieve adequate soft heap limit enforcement without 5263** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5264** 5265** The circumstances under which SQLite will enforce the soft heap limit may 5266** changes in future releases of SQLite. 5267*/ 5268SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_soft_heap_limit64(sqlite3_int64 N); 5269 5270/* 5271** CAPI3REF: Deprecated Soft Heap Limit Interface 5272** DEPRECATED 5273** 5274** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5275** interface. This routine is provided for historical compatibility 5276** only. All new applications should use the 5277** [sqlite3_soft_heap_limit64()] interface rather than this one. 5278*/ 5279SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_soft_heap_limit(int N); 5280 5281 5282/* 5283** CAPI3REF: Extract Metadata About A Column Of A Table 5284** METHOD: sqlite3 5285** 5286** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5287** information about column C of table T in database D 5288** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5289** interface returns SQLITE_OK and fills in the non-NULL pointers in 5290** the final five arguments with appropriate values if the specified 5291** column exists. ^The sqlite3_table_column_metadata() interface returns 5292** SQLITE_ERROR and if the specified column does not exist. 5293** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5294** NULL pointer, then this routine simply checks for the existance of the 5295** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5296** does not. 5297** 5298** ^The column is identified by the second, third and fourth parameters to 5299** this function. ^(The second parameter is either the name of the database 5300** (i.e. "main", "temp", or an attached database) containing the specified 5301** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5302** for the table using the same algorithm used by the database engine to 5303** resolve unqualified table references. 5304** 5305** ^The third and fourth parameters to this function are the table and column 5306** name of the desired column, respectively. 5307** 5308** ^Metadata is returned by writing to the memory locations passed as the 5th 5309** and subsequent parameters to this function. ^Any of these arguments may be 5310** NULL, in which case the corresponding element of metadata is omitted. 5311** 5312** ^(<blockquote> 5313** <table border="1"> 5314** <tr><th> Parameter <th> Output<br>Type <th> Description 5315** 5316** <tr><td> 5th <td> const char* <td> Data type 5317** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5318** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5319** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5320** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5321** </table> 5322** </blockquote>)^ 5323** 5324** ^The memory pointed to by the character pointers returned for the 5325** declaration type and collation sequence is valid until the next 5326** call to any SQLite API function. 5327** 5328** ^If the specified table is actually a view, an [error code] is returned. 5329** 5330** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5331** is not a [WITHOUT ROWID] table and an 5332** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5333** parameters are set for the explicitly declared column. ^(If there is no 5334** [INTEGER PRIMARY KEY] column, then the outputs 5335** for the [rowid] are set as follows: 5336** 5337** <pre> 5338** data type: "INTEGER" 5339** collation sequence: "BINARY" 5340** not null: 0 5341** primary key: 1 5342** auto increment: 0 5343** </pre>)^ 5344** 5345** ^This function causes all database schemas to be read from disk and 5346** parsed, if that has not already been done, and returns an error if 5347** any errors are encountered while loading the schema. 5348*/ 5349SQLITE_API int SQLITE_STDCALL sqlite3_table_column_metadata( 5350 sqlite3 *db, /* Connection handle */ 5351 const char *zDbName, /* Database name or NULL */ 5352 const char *zTableName, /* Table name */ 5353 const char *zColumnName, /* Column name */ 5354 char const **pzDataType, /* OUTPUT: Declared data type */ 5355 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5356 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5357 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5358 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5359); 5360 5361/* 5362** CAPI3REF: Load An Extension 5363** METHOD: sqlite3 5364** 5365** ^This interface loads an SQLite extension library from the named file. 5366** 5367** ^The sqlite3_load_extension() interface attempts to load an 5368** [SQLite extension] library contained in the file zFile. If 5369** the file cannot be loaded directly, attempts are made to load 5370** with various operating-system specific extensions added. 5371** So for example, if "samplelib" cannot be loaded, then names like 5372** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5373** be tried also. 5374** 5375** ^The entry point is zProc. 5376** ^(zProc may be 0, in which case SQLite will try to come up with an 5377** entry point name on its own. It first tries "sqlite3_extension_init". 5378** If that does not work, it constructs a name "sqlite3_X_init" where the 5379** X is consists of the lower-case equivalent of all ASCII alphabetic 5380** characters in the filename from the last "/" to the first following 5381** "." and omitting any initial "lib".)^ 5382** ^The sqlite3_load_extension() interface returns 5383** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5384** ^If an error occurs and pzErrMsg is not 0, then the 5385** [sqlite3_load_extension()] interface shall attempt to 5386** fill *pzErrMsg with error message text stored in memory 5387** obtained from [sqlite3_malloc()]. The calling function 5388** should free this memory by calling [sqlite3_free()]. 5389** 5390** ^Extension loading must be enabled using 5391** [sqlite3_enable_load_extension()] prior to calling this API, 5392** otherwise an error will be returned. 5393** 5394** See also the [load_extension() SQL function]. 5395*/ 5396SQLITE_API int SQLITE_STDCALL sqlite3_load_extension( 5397 sqlite3 *db, /* Load the extension into this database connection */ 5398 const char *zFile, /* Name of the shared library containing extension */ 5399 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5400 char **pzErrMsg /* Put error message here if not 0 */ 5401); 5402 5403/* 5404** CAPI3REF: Enable Or Disable Extension Loading 5405** METHOD: sqlite3 5406** 5407** ^So as not to open security holes in older applications that are 5408** unprepared to deal with [extension loading], and as a means of disabling 5409** [extension loading] while evaluating user-entered SQL, the following API 5410** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5411** 5412** ^Extension loading is off by default. 5413** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5414** to turn extension loading on and call it with onoff==0 to turn 5415** it back off again. 5416*/ 5417SQLITE_API int SQLITE_STDCALL sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5418 5419/* 5420** CAPI3REF: Automatically Load Statically Linked Extensions 5421** 5422** ^This interface causes the xEntryPoint() function to be invoked for 5423** each new [database connection] that is created. The idea here is that 5424** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5425** that is to be automatically loaded into all new database connections. 5426** 5427** ^(Even though the function prototype shows that xEntryPoint() takes 5428** no arguments and returns void, SQLite invokes xEntryPoint() with three 5429** arguments and expects and integer result as if the signature of the 5430** entry point where as follows: 5431** 5432** <blockquote><pre> 5433** int xEntryPoint( 5434** sqlite3 *db, 5435** const char **pzErrMsg, 5436** const struct sqlite3_api_routines *pThunk 5437** ); 5438** </pre></blockquote>)^ 5439** 5440** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5441** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5442** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5443** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5444** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5445** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5446** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5447** 5448** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5449** on the list of automatic extensions is a harmless no-op. ^No entry point 5450** will be called more than once for each database connection that is opened. 5451** 5452** See also: [sqlite3_reset_auto_extension()] 5453** and [sqlite3_cancel_auto_extension()] 5454*/ 5455SQLITE_API int SQLITE_STDCALL sqlite3_auto_extension(void (*xEntryPoint)(void)); 5456 5457/* 5458** CAPI3REF: Cancel Automatic Extension Loading 5459** 5460** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5461** initialization routine X that was registered using a prior call to 5462** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5463** routine returns 1 if initialization routine X was successfully 5464** unregistered and it returns 0 if X was not on the list of initialization 5465** routines. 5466*/ 5467SQLITE_API int SQLITE_STDCALL sqlite3_cancel_auto_extension(void (*xEntryPoint)(void)); 5468 5469/* 5470** CAPI3REF: Reset Automatic Extension Loading 5471** 5472** ^This interface disables all automatic extensions previously 5473** registered using [sqlite3_auto_extension()]. 5474*/ 5475SQLITE_API void SQLITE_STDCALL sqlite3_reset_auto_extension(void); 5476 5477/* 5478** The interface to the virtual-table mechanism is currently considered 5479** to be experimental. The interface might change in incompatible ways. 5480** If this is a problem for you, do not use the interface at this time. 5481** 5482** When the virtual-table mechanism stabilizes, we will declare the 5483** interface fixed, support it indefinitely, and remove this comment. 5484*/ 5485 5486/* 5487** Structures used by the virtual table interface 5488*/ 5489typedef struct sqlite3_vtab sqlite3_vtab; 5490typedef struct sqlite3_index_info sqlite3_index_info; 5491typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5492typedef struct sqlite3_module sqlite3_module; 5493 5494/* 5495** CAPI3REF: Virtual Table Object 5496** KEYWORDS: sqlite3_module {virtual table module} 5497** 5498** This structure, sometimes called a "virtual table module", 5499** defines the implementation of a [virtual tables]. 5500** This structure consists mostly of methods for the module. 5501** 5502** ^A virtual table module is created by filling in a persistent 5503** instance of this structure and passing a pointer to that instance 5504** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5505** ^The registration remains valid until it is replaced by a different 5506** module or until the [database connection] closes. The content 5507** of this structure must not change while it is registered with 5508** any database connection. 5509*/ 5510struct sqlite3_module { 5511 int iVersion; 5512 int (*xCreate)(sqlite3*, void *pAux, 5513 int argc, const char *const*argv, 5514 sqlite3_vtab **ppVTab, char**); 5515 int (*xConnect)(sqlite3*, void *pAux, 5516 int argc, const char *const*argv, 5517 sqlite3_vtab **ppVTab, char**); 5518 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5519 int (*xDisconnect)(sqlite3_vtab *pVTab); 5520 int (*xDestroy)(sqlite3_vtab *pVTab); 5521 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5522 int (*xClose)(sqlite3_vtab_cursor*); 5523 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5524 int argc, sqlite3_value **argv); 5525 int (*xNext)(sqlite3_vtab_cursor*); 5526 int (*xEof)(sqlite3_vtab_cursor*); 5527 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5528 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5529 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5530 int (*xBegin)(sqlite3_vtab *pVTab); 5531 int (*xSync)(sqlite3_vtab *pVTab); 5532 int (*xCommit)(sqlite3_vtab *pVTab); 5533 int (*xRollback)(sqlite3_vtab *pVTab); 5534 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5535 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5536 void **ppArg); 5537 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5538 /* The methods above are in version 1 of the sqlite_module object. Those 5539 ** below are for version 2 and greater. */ 5540 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5541 int (*xRelease)(sqlite3_vtab *pVTab, int); 5542 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5543}; 5544 5545/* 5546** CAPI3REF: Virtual Table Indexing Information 5547** KEYWORDS: sqlite3_index_info 5548** 5549** The sqlite3_index_info structure and its substructures is used as part 5550** of the [virtual table] interface to 5551** pass information into and receive the reply from the [xBestIndex] 5552** method of a [virtual table module]. The fields under **Inputs** are the 5553** inputs to xBestIndex and are read-only. xBestIndex inserts its 5554** results into the **Outputs** fields. 5555** 5556** ^(The aConstraint[] array records WHERE clause constraints of the form: 5557** 5558** <blockquote>column OP expr</blockquote> 5559** 5560** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5561** stored in aConstraint[].op using one of the 5562** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5563** ^(The index of the column is stored in 5564** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5565** expr on the right-hand side can be evaluated (and thus the constraint 5566** is usable) and false if it cannot.)^ 5567** 5568** ^The optimizer automatically inverts terms of the form "expr OP column" 5569** and makes other simplifications to the WHERE clause in an attempt to 5570** get as many WHERE clause terms into the form shown above as possible. 5571** ^The aConstraint[] array only reports WHERE clause terms that are 5572** relevant to the particular virtual table being queried. 5573** 5574** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5575** ^Each term of aOrderBy records a column of the ORDER BY clause. 5576** 5577** The [xBestIndex] method must fill aConstraintUsage[] with information 5578** about what parameters to pass to xFilter. ^If argvIndex>0 then 5579** the right-hand side of the corresponding aConstraint[] is evaluated 5580** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5581** is true, then the constraint is assumed to be fully handled by the 5582** virtual table and is not checked again by SQLite.)^ 5583** 5584** ^The idxNum and idxPtr values are recorded and passed into the 5585** [xFilter] method. 5586** ^[sqlite3_free()] is used to free idxPtr if and only if 5587** needToFreeIdxPtr is true. 5588** 5589** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5590** the correct order to satisfy the ORDER BY clause so that no separate 5591** sorting step is required. 5592** 5593** ^The estimatedCost value is an estimate of the cost of a particular 5594** strategy. A cost of N indicates that the cost of the strategy is similar 5595** to a linear scan of an SQLite table with N rows. A cost of log(N) 5596** indicates that the expense of the operation is similar to that of a 5597** binary search on a unique indexed field of an SQLite table with N rows. 5598** 5599** ^The estimatedRows value is an estimate of the number of rows that 5600** will be returned by the strategy. 5601** 5602** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 5603** structure for SQLite version 3.8.2. If a virtual table extension is 5604** used with an SQLite version earlier than 3.8.2, the results of attempting 5605** to read or write the estimatedRows field are undefined (but are likely 5606** to included crashing the application). The estimatedRows field should 5607** therefore only be used if [sqlite3_libversion_number()] returns a 5608** value greater than or equal to 3008002. 5609*/ 5610struct sqlite3_index_info { 5611 /* Inputs */ 5612 int nConstraint; /* Number of entries in aConstraint */ 5613 struct sqlite3_index_constraint { 5614 int iColumn; /* Column on left-hand side of constraint */ 5615 unsigned char op; /* Constraint operator */ 5616 unsigned char usable; /* True if this constraint is usable */ 5617 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5618 } *aConstraint; /* Table of WHERE clause constraints */ 5619 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5620 struct sqlite3_index_orderby { 5621 int iColumn; /* Column number */ 5622 unsigned char desc; /* True for DESC. False for ASC. */ 5623 } *aOrderBy; /* The ORDER BY clause */ 5624 /* Outputs */ 5625 struct sqlite3_index_constraint_usage { 5626 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5627 unsigned char omit; /* Do not code a test for this constraint */ 5628 } *aConstraintUsage; 5629 int idxNum; /* Number used to identify the index */ 5630 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5631 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5632 int orderByConsumed; /* True if output is already ordered */ 5633 double estimatedCost; /* Estimated cost of using this index */ 5634 /* Fields below are only available in SQLite 3.8.2 and later */ 5635 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 5636}; 5637 5638/* 5639** CAPI3REF: Virtual Table Constraint Operator Codes 5640** 5641** These macros defined the allowed values for the 5642** [sqlite3_index_info].aConstraint[].op field. Each value represents 5643** an operator that is part of a constraint term in the wHERE clause of 5644** a query that uses a [virtual table]. 5645*/ 5646#define SQLITE_INDEX_CONSTRAINT_EQ 2 5647#define SQLITE_INDEX_CONSTRAINT_GT 4 5648#define SQLITE_INDEX_CONSTRAINT_LE 8 5649#define SQLITE_INDEX_CONSTRAINT_LT 16 5650#define SQLITE_INDEX_CONSTRAINT_GE 32 5651#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5652 5653/* 5654** CAPI3REF: Register A Virtual Table Implementation 5655** METHOD: sqlite3 5656** 5657** ^These routines are used to register a new [virtual table module] name. 5658** ^Module names must be registered before 5659** creating a new [virtual table] using the module and before using a 5660** preexisting [virtual table] for the module. 5661** 5662** ^The module name is registered on the [database connection] specified 5663** by the first parameter. ^The name of the module is given by the 5664** second parameter. ^The third parameter is a pointer to 5665** the implementation of the [virtual table module]. ^The fourth 5666** parameter is an arbitrary client data pointer that is passed through 5667** into the [xCreate] and [xConnect] methods of the virtual table module 5668** when a new virtual table is be being created or reinitialized. 5669** 5670** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5671** is a pointer to a destructor for the pClientData. ^SQLite will 5672** invoke the destructor function (if it is not NULL) when SQLite 5673** no longer needs the pClientData pointer. ^The destructor will also 5674** be invoked if the call to sqlite3_create_module_v2() fails. 5675** ^The sqlite3_create_module() 5676** interface is equivalent to sqlite3_create_module_v2() with a NULL 5677** destructor. 5678*/ 5679SQLITE_API int SQLITE_STDCALL sqlite3_create_module( 5680 sqlite3 *db, /* SQLite connection to register module with */ 5681 const char *zName, /* Name of the module */ 5682 const sqlite3_module *p, /* Methods for the module */ 5683 void *pClientData /* Client data for xCreate/xConnect */ 5684); 5685SQLITE_API int SQLITE_STDCALL sqlite3_create_module_v2( 5686 sqlite3 *db, /* SQLite connection to register module with */ 5687 const char *zName, /* Name of the module */ 5688 const sqlite3_module *p, /* Methods for the module */ 5689 void *pClientData, /* Client data for xCreate/xConnect */ 5690 void(*xDestroy)(void*) /* Module destructor function */ 5691); 5692 5693/* 5694** CAPI3REF: Virtual Table Instance Object 5695** KEYWORDS: sqlite3_vtab 5696** 5697** Every [virtual table module] implementation uses a subclass 5698** of this object to describe a particular instance 5699** of the [virtual table]. Each subclass will 5700** be tailored to the specific needs of the module implementation. 5701** The purpose of this superclass is to define certain fields that are 5702** common to all module implementations. 5703** 5704** ^Virtual tables methods can set an error message by assigning a 5705** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5706** take care that any prior string is freed by a call to [sqlite3_free()] 5707** prior to assigning a new string to zErrMsg. ^After the error message 5708** is delivered up to the client application, the string will be automatically 5709** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5710*/ 5711struct sqlite3_vtab { 5712 const sqlite3_module *pModule; /* The module for this virtual table */ 5713 int nRef; /* Number of open cursors */ 5714 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5715 /* Virtual table implementations will typically add additional fields */ 5716}; 5717 5718/* 5719** CAPI3REF: Virtual Table Cursor Object 5720** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5721** 5722** Every [virtual table module] implementation uses a subclass of the 5723** following structure to describe cursors that point into the 5724** [virtual table] and are used 5725** to loop through the virtual table. Cursors are created using the 5726** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5727** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5728** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5729** of the module. Each module implementation will define 5730** the content of a cursor structure to suit its own needs. 5731** 5732** This superclass exists in order to define fields of the cursor that 5733** are common to all implementations. 5734*/ 5735struct sqlite3_vtab_cursor { 5736 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5737 /* Virtual table implementations will typically add additional fields */ 5738}; 5739 5740/* 5741** CAPI3REF: Declare The Schema Of A Virtual Table 5742** 5743** ^The [xCreate] and [xConnect] methods of a 5744** [virtual table module] call this interface 5745** to declare the format (the names and datatypes of the columns) of 5746** the virtual tables they implement. 5747*/ 5748SQLITE_API int SQLITE_STDCALL sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5749 5750/* 5751** CAPI3REF: Overload A Function For A Virtual Table 5752** METHOD: sqlite3 5753** 5754** ^(Virtual tables can provide alternative implementations of functions 5755** using the [xFindFunction] method of the [virtual table module]. 5756** But global versions of those functions 5757** must exist in order to be overloaded.)^ 5758** 5759** ^(This API makes sure a global version of a function with a particular 5760** name and number of parameters exists. If no such function exists 5761** before this API is called, a new function is created.)^ ^The implementation 5762** of the new function always causes an exception to be thrown. So 5763** the new function is not good for anything by itself. Its only 5764** purpose is to be a placeholder function that can be overloaded 5765** by a [virtual table]. 5766*/ 5767SQLITE_API int SQLITE_STDCALL sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5768 5769/* 5770** The interface to the virtual-table mechanism defined above (back up 5771** to a comment remarkably similar to this one) is currently considered 5772** to be experimental. The interface might change in incompatible ways. 5773** If this is a problem for you, do not use the interface at this time. 5774** 5775** When the virtual-table mechanism stabilizes, we will declare the 5776** interface fixed, support it indefinitely, and remove this comment. 5777*/ 5778 5779/* 5780** CAPI3REF: A Handle To An Open BLOB 5781** KEYWORDS: {BLOB handle} {BLOB handles} 5782** 5783** An instance of this object represents an open BLOB on which 5784** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5785** ^Objects of this type are created by [sqlite3_blob_open()] 5786** and destroyed by [sqlite3_blob_close()]. 5787** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5788** can be used to read or write small subsections of the BLOB. 5789** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5790*/ 5791typedef struct sqlite3_blob sqlite3_blob; 5792 5793/* 5794** CAPI3REF: Open A BLOB For Incremental I/O 5795** METHOD: sqlite3 5796** CONSTRUCTOR: sqlite3_blob 5797** 5798** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5799** in row iRow, column zColumn, table zTable in database zDb; 5800** in other words, the same BLOB that would be selected by: 5801** 5802** <pre> 5803** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5804** </pre>)^ 5805** 5806** ^(Parameter zDb is not the filename that contains the database, but 5807** rather the symbolic name of the database. For attached databases, this is 5808** the name that appears after the AS keyword in the [ATTACH] statement. 5809** For the main database file, the database name is "main". For TEMP 5810** tables, the database name is "temp".)^ 5811** 5812** ^If the flags parameter is non-zero, then the BLOB is opened for read 5813** and write access. ^If the flags parameter is zero, the BLOB is opened for 5814** read-only access. 5815** 5816** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 5817** in *ppBlob. Otherwise an [error code] is returned and, unless the error 5818** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 5819** the API is not misused, it is always safe to call [sqlite3_blob_close()] 5820** on *ppBlob after this function it returns. 5821** 5822** This function fails with SQLITE_ERROR if any of the following are true: 5823** <ul> 5824** <li> ^(Database zDb does not exist)^, 5825** <li> ^(Table zTable does not exist within database zDb)^, 5826** <li> ^(Table zTable is a WITHOUT ROWID table)^, 5827** <li> ^(Column zColumn does not exist)^, 5828** <li> ^(Row iRow is not present in the table)^, 5829** <li> ^(The specified column of row iRow contains a value that is not 5830** a TEXT or BLOB value)^, 5831** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 5832** constraint and the blob is being opened for read/write access)^, 5833** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 5834** column zColumn is part of a [child key] definition and the blob is 5835** being opened for read/write access)^. 5836** </ul> 5837** 5838** ^Unless it returns SQLITE_MISUSE, this function sets the 5839** [database connection] error code and message accessible via 5840** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 5841** 5842** 5843** ^(If the row that a BLOB handle points to is modified by an 5844** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5845** then the BLOB handle is marked as "expired". 5846** This is true if any column of the row is changed, even a column 5847** other than the one the BLOB handle is open on.)^ 5848** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5849** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5850** ^(Changes written into a BLOB prior to the BLOB expiring are not 5851** rolled back by the expiration of the BLOB. Such changes will eventually 5852** commit if the transaction continues to completion.)^ 5853** 5854** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5855** the opened blob. ^The size of a blob may not be changed by this 5856** interface. Use the [UPDATE] SQL command to change the size of a 5857** blob. 5858** 5859** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5860** and the built-in [zeroblob] SQL function may be used to create a 5861** zero-filled blob to read or write using the incremental-blob interface. 5862** 5863** To avoid a resource leak, every open [BLOB handle] should eventually 5864** be released by a call to [sqlite3_blob_close()]. 5865*/ 5866SQLITE_API int SQLITE_STDCALL sqlite3_blob_open( 5867 sqlite3*, 5868 const char *zDb, 5869 const char *zTable, 5870 const char *zColumn, 5871 sqlite3_int64 iRow, 5872 int flags, 5873 sqlite3_blob **ppBlob 5874); 5875 5876/* 5877** CAPI3REF: Move a BLOB Handle to a New Row 5878** METHOD: sqlite3_blob 5879** 5880** ^This function is used to move an existing blob handle so that it points 5881** to a different row of the same database table. ^The new row is identified 5882** by the rowid value passed as the second argument. Only the row can be 5883** changed. ^The database, table and column on which the blob handle is open 5884** remain the same. Moving an existing blob handle to a new row can be 5885** faster than closing the existing handle and opening a new one. 5886** 5887** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5888** it must exist and there must be either a blob or text value stored in 5889** the nominated column.)^ ^If the new row is not present in the table, or if 5890** it does not contain a blob or text value, or if another error occurs, an 5891** SQLite error code is returned and the blob handle is considered aborted. 5892** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5893** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5894** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5895** always returns zero. 5896** 5897** ^This function sets the database handle error code and message. 5898*/ 5899SQLITE_API int SQLITE_STDCALL sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5900 5901/* 5902** CAPI3REF: Close A BLOB Handle 5903** DESTRUCTOR: sqlite3_blob 5904** 5905** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 5906** unconditionally. Even if this routine returns an error code, the 5907** handle is still closed.)^ 5908** 5909** ^If the blob handle being closed was opened for read-write access, and if 5910** the database is in auto-commit mode and there are no other open read-write 5911** blob handles or active write statements, the current transaction is 5912** committed. ^If an error occurs while committing the transaction, an error 5913** code is returned and the transaction rolled back. 5914** 5915** Calling this function with an argument that is not a NULL pointer or an 5916** open blob handle results in undefined behaviour. ^Calling this routine 5917** with a null pointer (such as would be returned by a failed call to 5918** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 5919** is passed a valid open blob handle, the values returned by the 5920** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 5921*/ 5922SQLITE_API int SQLITE_STDCALL sqlite3_blob_close(sqlite3_blob *); 5923 5924/* 5925** CAPI3REF: Return The Size Of An Open BLOB 5926** METHOD: sqlite3_blob 5927** 5928** ^Returns the size in bytes of the BLOB accessible via the 5929** successfully opened [BLOB handle] in its only argument. ^The 5930** incremental blob I/O routines can only read or overwriting existing 5931** blob content; they cannot change the size of a blob. 5932** 5933** This routine only works on a [BLOB handle] which has been created 5934** by a prior successful call to [sqlite3_blob_open()] and which has not 5935** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5936** to this routine results in undefined and probably undesirable behavior. 5937*/ 5938SQLITE_API int SQLITE_STDCALL sqlite3_blob_bytes(sqlite3_blob *); 5939 5940/* 5941** CAPI3REF: Read Data From A BLOB Incrementally 5942** METHOD: sqlite3_blob 5943** 5944** ^(This function is used to read data from an open [BLOB handle] into a 5945** caller-supplied buffer. N bytes of data are copied into buffer Z 5946** from the open BLOB, starting at offset iOffset.)^ 5947** 5948** ^If offset iOffset is less than N bytes from the end of the BLOB, 5949** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5950** less than zero, [SQLITE_ERROR] is returned and no data is read. 5951** ^The size of the blob (and hence the maximum value of N+iOffset) 5952** can be determined using the [sqlite3_blob_bytes()] interface. 5953** 5954** ^An attempt to read from an expired [BLOB handle] fails with an 5955** error code of [SQLITE_ABORT]. 5956** 5957** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5958** Otherwise, an [error code] or an [extended error code] is returned.)^ 5959** 5960** This routine only works on a [BLOB handle] which has been created 5961** by a prior successful call to [sqlite3_blob_open()] and which has not 5962** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5963** to this routine results in undefined and probably undesirable behavior. 5964** 5965** See also: [sqlite3_blob_write()]. 5966*/ 5967SQLITE_API int SQLITE_STDCALL sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5968 5969/* 5970** CAPI3REF: Write Data Into A BLOB Incrementally 5971** METHOD: sqlite3_blob 5972** 5973** ^(This function is used to write data into an open [BLOB handle] from a 5974** caller-supplied buffer. N bytes of data are copied from the buffer Z 5975** into the open BLOB, starting at offset iOffset.)^ 5976** 5977** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5978** Otherwise, an [error code] or an [extended error code] is returned.)^ 5979** ^Unless SQLITE_MISUSE is returned, this function sets the 5980** [database connection] error code and message accessible via 5981** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 5982** 5983** ^If the [BLOB handle] passed as the first argument was not opened for 5984** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5985** this function returns [SQLITE_READONLY]. 5986** 5987** This function may only modify the contents of the BLOB; it is 5988** not possible to increase the size of a BLOB using this API. 5989** ^If offset iOffset is less than N bytes from the end of the BLOB, 5990** [SQLITE_ERROR] is returned and no data is written. The size of the 5991** BLOB (and hence the maximum value of N+iOffset) can be determined 5992** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 5993** than zero [SQLITE_ERROR] is returned and no data is written. 5994** 5995** ^An attempt to write to an expired [BLOB handle] fails with an 5996** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5997** before the [BLOB handle] expired are not rolled back by the 5998** expiration of the handle, though of course those changes might 5999** have been overwritten by the statement that expired the BLOB handle 6000** or by other independent statements. 6001** 6002** This routine only works on a [BLOB handle] which has been created 6003** by a prior successful call to [sqlite3_blob_open()] and which has not 6004** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6005** to this routine results in undefined and probably undesirable behavior. 6006** 6007** See also: [sqlite3_blob_read()]. 6008*/ 6009SQLITE_API int SQLITE_STDCALL sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6010 6011/* 6012** CAPI3REF: Virtual File System Objects 6013** 6014** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6015** that SQLite uses to interact 6016** with the underlying operating system. Most SQLite builds come with a 6017** single default VFS that is appropriate for the host computer. 6018** New VFSes can be registered and existing VFSes can be unregistered. 6019** The following interfaces are provided. 6020** 6021** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6022** ^Names are case sensitive. 6023** ^Names are zero-terminated UTF-8 strings. 6024** ^If there is no match, a NULL pointer is returned. 6025** ^If zVfsName is NULL then the default VFS is returned. 6026** 6027** ^New VFSes are registered with sqlite3_vfs_register(). 6028** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6029** ^The same VFS can be registered multiple times without injury. 6030** ^To make an existing VFS into the default VFS, register it again 6031** with the makeDflt flag set. If two different VFSes with the 6032** same name are registered, the behavior is undefined. If a 6033** VFS is registered with a name that is NULL or an empty string, 6034** then the behavior is undefined. 6035** 6036** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6037** ^(If the default VFS is unregistered, another VFS is chosen as 6038** the default. The choice for the new VFS is arbitrary.)^ 6039*/ 6040SQLITE_API sqlite3_vfs *SQLITE_STDCALL sqlite3_vfs_find(const char *zVfsName); 6041SQLITE_API int SQLITE_STDCALL sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6042SQLITE_API int SQLITE_STDCALL sqlite3_vfs_unregister(sqlite3_vfs*); 6043 6044/* 6045** CAPI3REF: Mutexes 6046** 6047** The SQLite core uses these routines for thread 6048** synchronization. Though they are intended for internal 6049** use by SQLite, code that links against SQLite is 6050** permitted to use any of these routines. 6051** 6052** The SQLite source code contains multiple implementations 6053** of these mutex routines. An appropriate implementation 6054** is selected automatically at compile-time. The following 6055** implementations are available in the SQLite core: 6056** 6057** <ul> 6058** <li> SQLITE_MUTEX_PTHREADS 6059** <li> SQLITE_MUTEX_W32 6060** <li> SQLITE_MUTEX_NOOP 6061** </ul> 6062** 6063** The SQLITE_MUTEX_NOOP implementation is a set of routines 6064** that does no real locking and is appropriate for use in 6065** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6066** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6067** and Windows. 6068** 6069** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6070** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6071** implementation is included with the library. In this case the 6072** application must supply a custom mutex implementation using the 6073** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6074** before calling sqlite3_initialize() or any other public sqlite3_ 6075** function that calls sqlite3_initialize(). 6076** 6077** ^The sqlite3_mutex_alloc() routine allocates a new 6078** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6079** routine returns NULL if it is unable to allocate the requested 6080** mutex. The argument to sqlite3_mutex_alloc() must one of these 6081** integer constants: 6082** 6083** <ul> 6084** <li> SQLITE_MUTEX_FAST 6085** <li> SQLITE_MUTEX_RECURSIVE 6086** <li> SQLITE_MUTEX_STATIC_MASTER 6087** <li> SQLITE_MUTEX_STATIC_MEM 6088** <li> SQLITE_MUTEX_STATIC_OPEN 6089** <li> SQLITE_MUTEX_STATIC_PRNG 6090** <li> SQLITE_MUTEX_STATIC_LRU 6091** <li> SQLITE_MUTEX_STATIC_PMEM 6092** <li> SQLITE_MUTEX_STATIC_APP1 6093** <li> SQLITE_MUTEX_STATIC_APP2 6094** <li> SQLITE_MUTEX_STATIC_APP3 6095** </ul> 6096** 6097** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6098** cause sqlite3_mutex_alloc() to create 6099** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6100** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6101** The mutex implementation does not need to make a distinction 6102** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6103** not want to. SQLite will only request a recursive mutex in 6104** cases where it really needs one. If a faster non-recursive mutex 6105** implementation is available on the host platform, the mutex subsystem 6106** might return such a mutex in response to SQLITE_MUTEX_FAST. 6107** 6108** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6109** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6110** a pointer to a static preexisting mutex. ^Nine static mutexes are 6111** used by the current version of SQLite. Future versions of SQLite 6112** may add additional static mutexes. Static mutexes are for internal 6113** use by SQLite only. Applications that use SQLite mutexes should 6114** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6115** SQLITE_MUTEX_RECURSIVE. 6116** 6117** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6118** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6119** returns a different mutex on every call. ^For the static 6120** mutex types, the same mutex is returned on every call that has 6121** the same type number. 6122** 6123** ^The sqlite3_mutex_free() routine deallocates a previously 6124** allocated dynamic mutex. Attempting to deallocate a static 6125** mutex results in undefined behavior. 6126** 6127** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6128** to enter a mutex. ^If another thread is already within the mutex, 6129** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6130** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6131** upon successful entry. ^(Mutexes created using 6132** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6133** In such cases, the 6134** mutex must be exited an equal number of times before another thread 6135** can enter.)^ If the same thread tries to enter any mutex other 6136** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6137** 6138** ^(Some systems (for example, Windows 95) do not support the operation 6139** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6140** will always return SQLITE_BUSY. The SQLite core only ever uses 6141** sqlite3_mutex_try() as an optimization so this is acceptable 6142** behavior.)^ 6143** 6144** ^The sqlite3_mutex_leave() routine exits a mutex that was 6145** previously entered by the same thread. The behavior 6146** is undefined if the mutex is not currently entered by the 6147** calling thread or is not currently allocated. 6148** 6149** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6150** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6151** behave as no-ops. 6152** 6153** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6154*/ 6155SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_mutex_alloc(int); 6156SQLITE_API void SQLITE_STDCALL sqlite3_mutex_free(sqlite3_mutex*); 6157SQLITE_API void SQLITE_STDCALL sqlite3_mutex_enter(sqlite3_mutex*); 6158SQLITE_API int SQLITE_STDCALL sqlite3_mutex_try(sqlite3_mutex*); 6159SQLITE_API void SQLITE_STDCALL sqlite3_mutex_leave(sqlite3_mutex*); 6160 6161/* 6162** CAPI3REF: Mutex Methods Object 6163** 6164** An instance of this structure defines the low-level routines 6165** used to allocate and use mutexes. 6166** 6167** Usually, the default mutex implementations provided by SQLite are 6168** sufficient, however the application has the option of substituting a custom 6169** implementation for specialized deployments or systems for which SQLite 6170** does not provide a suitable implementation. In this case, the application 6171** creates and populates an instance of this structure to pass 6172** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6173** Additionally, an instance of this structure can be used as an 6174** output variable when querying the system for the current mutex 6175** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6176** 6177** ^The xMutexInit method defined by this structure is invoked as 6178** part of system initialization by the sqlite3_initialize() function. 6179** ^The xMutexInit routine is called by SQLite exactly once for each 6180** effective call to [sqlite3_initialize()]. 6181** 6182** ^The xMutexEnd method defined by this structure is invoked as 6183** part of system shutdown by the sqlite3_shutdown() function. The 6184** implementation of this method is expected to release all outstanding 6185** resources obtained by the mutex methods implementation, especially 6186** those obtained by the xMutexInit method. ^The xMutexEnd() 6187** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6188** 6189** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6190** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6191** xMutexNotheld) implement the following interfaces (respectively): 6192** 6193** <ul> 6194** <li> [sqlite3_mutex_alloc()] </li> 6195** <li> [sqlite3_mutex_free()] </li> 6196** <li> [sqlite3_mutex_enter()] </li> 6197** <li> [sqlite3_mutex_try()] </li> 6198** <li> [sqlite3_mutex_leave()] </li> 6199** <li> [sqlite3_mutex_held()] </li> 6200** <li> [sqlite3_mutex_notheld()] </li> 6201** </ul>)^ 6202** 6203** The only difference is that the public sqlite3_XXX functions enumerated 6204** above silently ignore any invocations that pass a NULL pointer instead 6205** of a valid mutex handle. The implementations of the methods defined 6206** by this structure are not required to handle this case, the results 6207** of passing a NULL pointer instead of a valid mutex handle are undefined 6208** (i.e. it is acceptable to provide an implementation that segfaults if 6209** it is passed a NULL pointer). 6210** 6211** The xMutexInit() method must be threadsafe. It must be harmless to 6212** invoke xMutexInit() multiple times within the same process and without 6213** intervening calls to xMutexEnd(). Second and subsequent calls to 6214** xMutexInit() must be no-ops. 6215** 6216** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6217** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6218** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6219** memory allocation for a fast or recursive mutex. 6220** 6221** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6222** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6223** If xMutexInit fails in any way, it is expected to clean up after itself 6224** prior to returning. 6225*/ 6226typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6227struct sqlite3_mutex_methods { 6228 int (*xMutexInit)(void); 6229 int (*xMutexEnd)(void); 6230 sqlite3_mutex *(*xMutexAlloc)(int); 6231 void (*xMutexFree)(sqlite3_mutex *); 6232 void (*xMutexEnter)(sqlite3_mutex *); 6233 int (*xMutexTry)(sqlite3_mutex *); 6234 void (*xMutexLeave)(sqlite3_mutex *); 6235 int (*xMutexHeld)(sqlite3_mutex *); 6236 int (*xMutexNotheld)(sqlite3_mutex *); 6237}; 6238 6239/* 6240** CAPI3REF: Mutex Verification Routines 6241** 6242** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6243** are intended for use inside assert() statements. The SQLite core 6244** never uses these routines except inside an assert() and applications 6245** are advised to follow the lead of the core. The SQLite core only 6246** provides implementations for these routines when it is compiled 6247** with the SQLITE_DEBUG flag. External mutex implementations 6248** are only required to provide these routines if SQLITE_DEBUG is 6249** defined and if NDEBUG is not defined. 6250** 6251** These routines should return true if the mutex in their argument 6252** is held or not held, respectively, by the calling thread. 6253** 6254** The implementation is not required to provide versions of these 6255** routines that actually work. If the implementation does not provide working 6256** versions of these routines, it should at least provide stubs that always 6257** return true so that one does not get spurious assertion failures. 6258** 6259** If the argument to sqlite3_mutex_held() is a NULL pointer then 6260** the routine should return 1. This seems counter-intuitive since 6261** clearly the mutex cannot be held if it does not exist. But 6262** the reason the mutex does not exist is because the build is not 6263** using mutexes. And we do not want the assert() containing the 6264** call to sqlite3_mutex_held() to fail, so a non-zero return is 6265** the appropriate thing to do. The sqlite3_mutex_notheld() 6266** interface should also return 1 when given a NULL pointer. 6267*/ 6268#ifndef NDEBUG 6269SQLITE_API int SQLITE_STDCALL sqlite3_mutex_held(sqlite3_mutex*); 6270SQLITE_API int SQLITE_STDCALL sqlite3_mutex_notheld(sqlite3_mutex*); 6271#endif 6272 6273/* 6274** CAPI3REF: Mutex Types 6275** 6276** The [sqlite3_mutex_alloc()] interface takes a single argument 6277** which is one of these integer constants. 6278** 6279** The set of static mutexes may change from one SQLite release to the 6280** next. Applications that override the built-in mutex logic must be 6281** prepared to accommodate additional static mutexes. 6282*/ 6283#define SQLITE_MUTEX_FAST 0 6284#define SQLITE_MUTEX_RECURSIVE 1 6285#define SQLITE_MUTEX_STATIC_MASTER 2 6286#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6287#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6288#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6289#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 6290#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6291#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6292#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6293#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6294#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6295#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6296#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6297#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6298#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6299 6300/* 6301** CAPI3REF: Retrieve the mutex for a database connection 6302** METHOD: sqlite3 6303** 6304** ^This interface returns a pointer the [sqlite3_mutex] object that 6305** serializes access to the [database connection] given in the argument 6306** when the [threading mode] is Serialized. 6307** ^If the [threading mode] is Single-thread or Multi-thread then this 6308** routine returns a NULL pointer. 6309*/ 6310SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_db_mutex(sqlite3*); 6311 6312/* 6313** CAPI3REF: Low-Level Control Of Database Files 6314** METHOD: sqlite3 6315** 6316** ^The [sqlite3_file_control()] interface makes a direct call to the 6317** xFileControl method for the [sqlite3_io_methods] object associated 6318** with a particular database identified by the second argument. ^The 6319** name of the database is "main" for the main database or "temp" for the 6320** TEMP database, or the name that appears after the AS keyword for 6321** databases that are added using the [ATTACH] SQL command. 6322** ^A NULL pointer can be used in place of "main" to refer to the 6323** main database file. 6324** ^The third and fourth parameters to this routine 6325** are passed directly through to the second and third parameters of 6326** the xFileControl method. ^The return value of the xFileControl 6327** method becomes the return value of this routine. 6328** 6329** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6330** a pointer to the underlying [sqlite3_file] object to be written into 6331** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6332** case is a short-circuit path which does not actually invoke the 6333** underlying sqlite3_io_methods.xFileControl method. 6334** 6335** ^If the second parameter (zDbName) does not match the name of any 6336** open database file, then SQLITE_ERROR is returned. ^This error 6337** code is not remembered and will not be recalled by [sqlite3_errcode()] 6338** or [sqlite3_errmsg()]. The underlying xFileControl method might 6339** also return SQLITE_ERROR. There is no way to distinguish between 6340** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6341** xFileControl method. 6342** 6343** See also: [SQLITE_FCNTL_LOCKSTATE] 6344*/ 6345SQLITE_API int SQLITE_STDCALL sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6346 6347/* 6348** CAPI3REF: Testing Interface 6349** 6350** ^The sqlite3_test_control() interface is used to read out internal 6351** state of SQLite and to inject faults into SQLite for testing 6352** purposes. ^The first parameter is an operation code that determines 6353** the number, meaning, and operation of all subsequent parameters. 6354** 6355** This interface is not for use by applications. It exists solely 6356** for verifying the correct operation of the SQLite library. Depending 6357** on how the SQLite library is compiled, this interface might not exist. 6358** 6359** The details of the operation codes, their meanings, the parameters 6360** they take, and what they do are all subject to change without notice. 6361** Unlike most of the SQLite API, this function is not guaranteed to 6362** operate consistently from one release to the next. 6363*/ 6364SQLITE_API int SQLITE_CDECL sqlite3_test_control(int op, ...); 6365 6366/* 6367** CAPI3REF: Testing Interface Operation Codes 6368** 6369** These constants are the valid operation code parameters used 6370** as the first argument to [sqlite3_test_control()]. 6371** 6372** These parameters and their meanings are subject to change 6373** without notice. These values are for testing purposes only. 6374** Applications should not use any of these parameters or the 6375** [sqlite3_test_control()] interface. 6376*/ 6377#define SQLITE_TESTCTRL_FIRST 5 6378#define SQLITE_TESTCTRL_PRNG_SAVE 5 6379#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6380#define SQLITE_TESTCTRL_PRNG_RESET 7 6381#define SQLITE_TESTCTRL_BITVEC_TEST 8 6382#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6383#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6384#define SQLITE_TESTCTRL_PENDING_BYTE 11 6385#define SQLITE_TESTCTRL_ASSERT 12 6386#define SQLITE_TESTCTRL_ALWAYS 13 6387#define SQLITE_TESTCTRL_RESERVE 14 6388#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6389#define SQLITE_TESTCTRL_ISKEYWORD 16 6390#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6391#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6392#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6393#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6394#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6395#define SQLITE_TESTCTRL_BYTEORDER 22 6396#define SQLITE_TESTCTRL_ISINIT 23 6397#define SQLITE_TESTCTRL_SORTER_MMAP 24 6398#define SQLITE_TESTCTRL_IMPOSTER 25 6399#define SQLITE_TESTCTRL_LAST 25 6400 6401/* 6402** CAPI3REF: SQLite Runtime Status 6403** 6404** ^These interfaces are used to retrieve runtime status information 6405** about the performance of SQLite, and optionally to reset various 6406** highwater marks. ^The first argument is an integer code for 6407** the specific parameter to measure. ^(Recognized integer codes 6408** are of the form [status parameters | SQLITE_STATUS_...].)^ 6409** ^The current value of the parameter is returned into *pCurrent. 6410** ^The highest recorded value is returned in *pHighwater. ^If the 6411** resetFlag is true, then the highest record value is reset after 6412** *pHighwater is written. ^(Some parameters do not record the highest 6413** value. For those parameters 6414** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6415** ^(Other parameters record only the highwater mark and not the current 6416** value. For these latter parameters nothing is written into *pCurrent.)^ 6417** 6418** ^The sqlite3_status() and sqlite3_status64() routines return 6419** SQLITE_OK on success and a non-zero [error code] on failure. 6420** 6421** If either the current value or the highwater mark is too large to 6422** be represented by a 32-bit integer, then the values returned by 6423** sqlite3_status() are undefined. 6424** 6425** See also: [sqlite3_db_status()] 6426*/ 6427SQLITE_API int SQLITE_STDCALL sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6428SQLITE_API int SQLITE_STDCALL sqlite3_status64( 6429 int op, 6430 sqlite3_int64 *pCurrent, 6431 sqlite3_int64 *pHighwater, 6432 int resetFlag 6433); 6434 6435 6436/* 6437** CAPI3REF: Status Parameters 6438** KEYWORDS: {status parameters} 6439** 6440** These integer constants designate various run-time status parameters 6441** that can be returned by [sqlite3_status()]. 6442** 6443** <dl> 6444** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6445** <dd>This parameter is the current amount of memory checked out 6446** using [sqlite3_malloc()], either directly or indirectly. The 6447** figure includes calls made to [sqlite3_malloc()] by the application 6448** and internal memory usage by the SQLite library. Scratch memory 6449** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6450** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6451** this parameter. The amount returned is the sum of the allocation 6452** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6453** 6454** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6455** <dd>This parameter records the largest memory allocation request 6456** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6457** internal equivalents). Only the value returned in the 6458** *pHighwater parameter to [sqlite3_status()] is of interest. 6459** The value written into the *pCurrent parameter is undefined.</dd>)^ 6460** 6461** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6462** <dd>This parameter records the number of separate memory allocations 6463** currently checked out.</dd>)^ 6464** 6465** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6466** <dd>This parameter returns the number of pages used out of the 6467** [pagecache memory allocator] that was configured using 6468** [SQLITE_CONFIG_PAGECACHE]. The 6469** value returned is in pages, not in bytes.</dd>)^ 6470** 6471** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6472** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6473** <dd>This parameter returns the number of bytes of page cache 6474** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6475** buffer and where forced to overflow to [sqlite3_malloc()]. The 6476** returned value includes allocations that overflowed because they 6477** where too large (they were larger than the "sz" parameter to 6478** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6479** no space was left in the page cache.</dd>)^ 6480** 6481** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6482** <dd>This parameter records the largest memory allocation request 6483** handed to [pagecache memory allocator]. Only the value returned in the 6484** *pHighwater parameter to [sqlite3_status()] is of interest. 6485** The value written into the *pCurrent parameter is undefined.</dd>)^ 6486** 6487** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6488** <dd>This parameter returns the number of allocations used out of the 6489** [scratch memory allocator] configured using 6490** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6491** in bytes. Since a single thread may only have one scratch allocation 6492** outstanding at time, this parameter also reports the number of threads 6493** using scratch memory at the same time.</dd>)^ 6494** 6495** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6496** <dd>This parameter returns the number of bytes of scratch memory 6497** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6498** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6499** returned include overflows because the requested allocation was too 6500** larger (that is, because the requested allocation was larger than the 6501** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6502** slots were available. 6503** </dd>)^ 6504** 6505** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6506** <dd>This parameter records the largest memory allocation request 6507** handed to [scratch memory allocator]. Only the value returned in the 6508** *pHighwater parameter to [sqlite3_status()] is of interest. 6509** The value written into the *pCurrent parameter is undefined.</dd>)^ 6510** 6511** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6512** <dd>This parameter records the deepest parser stack. It is only 6513** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6514** </dl> 6515** 6516** New status parameters may be added from time to time. 6517*/ 6518#define SQLITE_STATUS_MEMORY_USED 0 6519#define SQLITE_STATUS_PAGECACHE_USED 1 6520#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6521#define SQLITE_STATUS_SCRATCH_USED 3 6522#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6523#define SQLITE_STATUS_MALLOC_SIZE 5 6524#define SQLITE_STATUS_PARSER_STACK 6 6525#define SQLITE_STATUS_PAGECACHE_SIZE 7 6526#define SQLITE_STATUS_SCRATCH_SIZE 8 6527#define SQLITE_STATUS_MALLOC_COUNT 9 6528 6529/* 6530** CAPI3REF: Database Connection Status 6531** METHOD: sqlite3 6532** 6533** ^This interface is used to retrieve runtime status information 6534** about a single [database connection]. ^The first argument is the 6535** database connection object to be interrogated. ^The second argument 6536** is an integer constant, taken from the set of 6537** [SQLITE_DBSTATUS options], that 6538** determines the parameter to interrogate. The set of 6539** [SQLITE_DBSTATUS options] is likely 6540** to grow in future releases of SQLite. 6541** 6542** ^The current value of the requested parameter is written into *pCur 6543** and the highest instantaneous value is written into *pHiwtr. ^If 6544** the resetFlg is true, then the highest instantaneous value is 6545** reset back down to the current value. 6546** 6547** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6548** non-zero [error code] on failure. 6549** 6550** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6551*/ 6552SQLITE_API int SQLITE_STDCALL sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6553 6554/* 6555** CAPI3REF: Status Parameters for database connections 6556** KEYWORDS: {SQLITE_DBSTATUS options} 6557** 6558** These constants are the available integer "verbs" that can be passed as 6559** the second argument to the [sqlite3_db_status()] interface. 6560** 6561** New verbs may be added in future releases of SQLite. Existing verbs 6562** might be discontinued. Applications should check the return code from 6563** [sqlite3_db_status()] to make sure that the call worked. 6564** The [sqlite3_db_status()] interface will return a non-zero error code 6565** if a discontinued or unsupported verb is invoked. 6566** 6567** <dl> 6568** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6569** <dd>This parameter returns the number of lookaside memory slots currently 6570** checked out.</dd>)^ 6571** 6572** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6573** <dd>This parameter returns the number malloc attempts that were 6574** satisfied using lookaside memory. Only the high-water value is meaningful; 6575** the current value is always zero.)^ 6576** 6577** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6578** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6579** <dd>This parameter returns the number malloc attempts that might have 6580** been satisfied using lookaside memory but failed due to the amount of 6581** memory requested being larger than the lookaside slot size. 6582** Only the high-water value is meaningful; 6583** the current value is always zero.)^ 6584** 6585** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6586** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6587** <dd>This parameter returns the number malloc attempts that might have 6588** been satisfied using lookaside memory but failed due to all lookaside 6589** memory already being in use. 6590** Only the high-water value is meaningful; 6591** the current value is always zero.)^ 6592** 6593** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6594** <dd>This parameter returns the approximate number of bytes of heap 6595** memory used by all pager caches associated with the database connection.)^ 6596** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6597** 6598** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6599** <dd>This parameter returns the approximate number of bytes of heap 6600** memory used to store the schema for all databases associated 6601** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6602** ^The full amount of memory used by the schemas is reported, even if the 6603** schema memory is shared with other database connections due to 6604** [shared cache mode] being enabled. 6605** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6606** 6607** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6608** <dd>This parameter returns the approximate number of bytes of heap 6609** and lookaside memory used by all prepared statements associated with 6610** the database connection.)^ 6611** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6612** </dd> 6613** 6614** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6615** <dd>This parameter returns the number of pager cache hits that have 6616** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6617** is always 0. 6618** </dd> 6619** 6620** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6621** <dd>This parameter returns the number of pager cache misses that have 6622** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6623** is always 0. 6624** </dd> 6625** 6626** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6627** <dd>This parameter returns the number of dirty cache entries that have 6628** been written to disk. Specifically, the number of pages written to the 6629** wal file in wal mode databases, or the number of pages written to the 6630** database file in rollback mode databases. Any pages written as part of 6631** transaction rollback or database recovery operations are not included. 6632** If an IO or other error occurs while writing a page to disk, the effect 6633** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6634** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6635** </dd> 6636** 6637** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 6638** <dd>This parameter returns zero for the current value if and only if 6639** all foreign key constraints (deferred or immediate) have been 6640** resolved.)^ ^The highwater mark is always 0. 6641** </dd> 6642** </dl> 6643*/ 6644#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6645#define SQLITE_DBSTATUS_CACHE_USED 1 6646#define SQLITE_DBSTATUS_SCHEMA_USED 2 6647#define SQLITE_DBSTATUS_STMT_USED 3 6648#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6649#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6650#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6651#define SQLITE_DBSTATUS_CACHE_HIT 7 6652#define SQLITE_DBSTATUS_CACHE_MISS 8 6653#define SQLITE_DBSTATUS_CACHE_WRITE 9 6654#define SQLITE_DBSTATUS_DEFERRED_FKS 10 6655#define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */ 6656 6657 6658/* 6659** CAPI3REF: Prepared Statement Status 6660** METHOD: sqlite3_stmt 6661** 6662** ^(Each prepared statement maintains various 6663** [SQLITE_STMTSTATUS counters] that measure the number 6664** of times it has performed specific operations.)^ These counters can 6665** be used to monitor the performance characteristics of the prepared 6666** statements. For example, if the number of table steps greatly exceeds 6667** the number of table searches or result rows, that would tend to indicate 6668** that the prepared statement is using a full table scan rather than 6669** an index. 6670** 6671** ^(This interface is used to retrieve and reset counter values from 6672** a [prepared statement]. The first argument is the prepared statement 6673** object to be interrogated. The second argument 6674** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6675** to be interrogated.)^ 6676** ^The current value of the requested counter is returned. 6677** ^If the resetFlg is true, then the counter is reset to zero after this 6678** interface call returns. 6679** 6680** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6681*/ 6682SQLITE_API int SQLITE_STDCALL sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6683 6684/* 6685** CAPI3REF: Status Parameters for prepared statements 6686** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6687** 6688** These preprocessor macros define integer codes that name counter 6689** values associated with the [sqlite3_stmt_status()] interface. 6690** The meanings of the various counters are as follows: 6691** 6692** <dl> 6693** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6694** <dd>^This is the number of times that SQLite has stepped forward in 6695** a table as part of a full table scan. Large numbers for this counter 6696** may indicate opportunities for performance improvement through 6697** careful use of indices.</dd> 6698** 6699** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6700** <dd>^This is the number of sort operations that have occurred. 6701** A non-zero value in this counter may indicate an opportunity to 6702** improvement performance through careful use of indices.</dd> 6703** 6704** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6705** <dd>^This is the number of rows inserted into transient indices that 6706** were created automatically in order to help joins run faster. 6707** A non-zero value in this counter may indicate an opportunity to 6708** improvement performance by adding permanent indices that do not 6709** need to be reinitialized each time the statement is run.</dd> 6710** 6711** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 6712** <dd>^This is the number of virtual machine operations executed 6713** by the prepared statement if that number is less than or equal 6714** to 2147483647. The number of virtual machine operations can be 6715** used as a proxy for the total work done by the prepared statement. 6716** If the number of virtual machine operations exceeds 2147483647 6717** then the value returned by this statement status code is undefined. 6718** </dd> 6719** </dl> 6720*/ 6721#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6722#define SQLITE_STMTSTATUS_SORT 2 6723#define SQLITE_STMTSTATUS_AUTOINDEX 3 6724#define SQLITE_STMTSTATUS_VM_STEP 4 6725 6726/* 6727** CAPI3REF: Custom Page Cache Object 6728** 6729** The sqlite3_pcache type is opaque. It is implemented by 6730** the pluggable module. The SQLite core has no knowledge of 6731** its size or internal structure and never deals with the 6732** sqlite3_pcache object except by holding and passing pointers 6733** to the object. 6734** 6735** See [sqlite3_pcache_methods2] for additional information. 6736*/ 6737typedef struct sqlite3_pcache sqlite3_pcache; 6738 6739/* 6740** CAPI3REF: Custom Page Cache Object 6741** 6742** The sqlite3_pcache_page object represents a single page in the 6743** page cache. The page cache will allocate instances of this 6744** object. Various methods of the page cache use pointers to instances 6745** of this object as parameters or as their return value. 6746** 6747** See [sqlite3_pcache_methods2] for additional information. 6748*/ 6749typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6750struct sqlite3_pcache_page { 6751 void *pBuf; /* The content of the page */ 6752 void *pExtra; /* Extra information associated with the page */ 6753}; 6754 6755/* 6756** CAPI3REF: Application Defined Page Cache. 6757** KEYWORDS: {page cache} 6758** 6759** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6760** register an alternative page cache implementation by passing in an 6761** instance of the sqlite3_pcache_methods2 structure.)^ 6762** In many applications, most of the heap memory allocated by 6763** SQLite is used for the page cache. 6764** By implementing a 6765** custom page cache using this API, an application can better control 6766** the amount of memory consumed by SQLite, the way in which 6767** that memory is allocated and released, and the policies used to 6768** determine exactly which parts of a database file are cached and for 6769** how long. 6770** 6771** The alternative page cache mechanism is an 6772** extreme measure that is only needed by the most demanding applications. 6773** The built-in page cache is recommended for most uses. 6774** 6775** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6776** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6777** the application may discard the parameter after the call to 6778** [sqlite3_config()] returns.)^ 6779** 6780** [[the xInit() page cache method]] 6781** ^(The xInit() method is called once for each effective 6782** call to [sqlite3_initialize()])^ 6783** (usually only once during the lifetime of the process). ^(The xInit() 6784** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6785** The intent of the xInit() method is to set up global data structures 6786** required by the custom page cache implementation. 6787** ^(If the xInit() method is NULL, then the 6788** built-in default page cache is used instead of the application defined 6789** page cache.)^ 6790** 6791** [[the xShutdown() page cache method]] 6792** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6793** It can be used to clean up 6794** any outstanding resources before process shutdown, if required. 6795** ^The xShutdown() method may be NULL. 6796** 6797** ^SQLite automatically serializes calls to the xInit method, 6798** so the xInit method need not be threadsafe. ^The 6799** xShutdown method is only called from [sqlite3_shutdown()] so it does 6800** not need to be threadsafe either. All other methods must be threadsafe 6801** in multithreaded applications. 6802** 6803** ^SQLite will never invoke xInit() more than once without an intervening 6804** call to xShutdown(). 6805** 6806** [[the xCreate() page cache methods]] 6807** ^SQLite invokes the xCreate() method to construct a new cache instance. 6808** SQLite will typically create one cache instance for each open database file, 6809** though this is not guaranteed. ^The 6810** first parameter, szPage, is the size in bytes of the pages that must 6811** be allocated by the cache. ^szPage will always a power of two. ^The 6812** second parameter szExtra is a number of bytes of extra storage 6813** associated with each page cache entry. ^The szExtra parameter will 6814** a number less than 250. SQLite will use the 6815** extra szExtra bytes on each page to store metadata about the underlying 6816** database page on disk. The value passed into szExtra depends 6817** on the SQLite version, the target platform, and how SQLite was compiled. 6818** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6819** created will be used to cache database pages of a file stored on disk, or 6820** false if it is used for an in-memory database. The cache implementation 6821** does not have to do anything special based with the value of bPurgeable; 6822** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6823** never invoke xUnpin() except to deliberately delete a page. 6824** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6825** false will always have the "discard" flag set to true. 6826** ^Hence, a cache created with bPurgeable false will 6827** never contain any unpinned pages. 6828** 6829** [[the xCachesize() page cache method]] 6830** ^(The xCachesize() method may be called at any time by SQLite to set the 6831** suggested maximum cache-size (number of pages stored by) the cache 6832** instance passed as the first argument. This is the value configured using 6833** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6834** parameter, the implementation is not required to do anything with this 6835** value; it is advisory only. 6836** 6837** [[the xPagecount() page cache methods]] 6838** The xPagecount() method must return the number of pages currently 6839** stored in the cache, both pinned and unpinned. 6840** 6841** [[the xFetch() page cache methods]] 6842** The xFetch() method locates a page in the cache and returns a pointer to 6843** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6844** The pBuf element of the returned sqlite3_pcache_page object will be a 6845** pointer to a buffer of szPage bytes used to store the content of a 6846** single database page. The pExtra element of sqlite3_pcache_page will be 6847** a pointer to the szExtra bytes of extra storage that SQLite has requested 6848** for each entry in the page cache. 6849** 6850** The page to be fetched is determined by the key. ^The minimum key value 6851** is 1. After it has been retrieved using xFetch, the page is considered 6852** to be "pinned". 6853** 6854** If the requested page is already in the page cache, then the page cache 6855** implementation must return a pointer to the page buffer with its content 6856** intact. If the requested page is not already in the cache, then the 6857** cache implementation should use the value of the createFlag 6858** parameter to help it determined what action to take: 6859** 6860** <table border=1 width=85% align=center> 6861** <tr><th> createFlag <th> Behavior when page is not already in cache 6862** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6863** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6864** Otherwise return NULL. 6865** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6866** NULL if allocating a new page is effectively impossible. 6867** </table> 6868** 6869** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6870** will only use a createFlag of 2 after a prior call with a createFlag of 1 6871** failed.)^ In between the to xFetch() calls, SQLite may 6872** attempt to unpin one or more cache pages by spilling the content of 6873** pinned pages to disk and synching the operating system disk cache. 6874** 6875** [[the xUnpin() page cache method]] 6876** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6877** as its second argument. If the third parameter, discard, is non-zero, 6878** then the page must be evicted from the cache. 6879** ^If the discard parameter is 6880** zero, then the page may be discarded or retained at the discretion of 6881** page cache implementation. ^The page cache implementation 6882** may choose to evict unpinned pages at any time. 6883** 6884** The cache must not perform any reference counting. A single 6885** call to xUnpin() unpins the page regardless of the number of prior calls 6886** to xFetch(). 6887** 6888** [[the xRekey() page cache methods]] 6889** The xRekey() method is used to change the key value associated with the 6890** page passed as the second argument. If the cache 6891** previously contains an entry associated with newKey, it must be 6892** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6893** to be pinned. 6894** 6895** When SQLite calls the xTruncate() method, the cache must discard all 6896** existing cache entries with page numbers (keys) greater than or equal 6897** to the value of the iLimit parameter passed to xTruncate(). If any 6898** of these pages are pinned, they are implicitly unpinned, meaning that 6899** they can be safely discarded. 6900** 6901** [[the xDestroy() page cache method]] 6902** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6903** All resources associated with the specified cache should be freed. ^After 6904** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6905** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6906** functions. 6907** 6908** [[the xShrink() page cache method]] 6909** ^SQLite invokes the xShrink() method when it wants the page cache to 6910** free up as much of heap memory as possible. The page cache implementation 6911** is not obligated to free any memory, but well-behaved implementations should 6912** do their best. 6913*/ 6914typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6915struct sqlite3_pcache_methods2 { 6916 int iVersion; 6917 void *pArg; 6918 int (*xInit)(void*); 6919 void (*xShutdown)(void*); 6920 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6921 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6922 int (*xPagecount)(sqlite3_pcache*); 6923 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6924 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6925 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6926 unsigned oldKey, unsigned newKey); 6927 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6928 void (*xDestroy)(sqlite3_pcache*); 6929 void (*xShrink)(sqlite3_pcache*); 6930}; 6931 6932/* 6933** This is the obsolete pcache_methods object that has now been replaced 6934** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6935** retained in the header file for backwards compatibility only. 6936*/ 6937typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6938struct sqlite3_pcache_methods { 6939 void *pArg; 6940 int (*xInit)(void*); 6941 void (*xShutdown)(void*); 6942 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6943 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6944 int (*xPagecount)(sqlite3_pcache*); 6945 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6946 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6947 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6948 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6949 void (*xDestroy)(sqlite3_pcache*); 6950}; 6951 6952 6953/* 6954** CAPI3REF: Online Backup Object 6955** 6956** The sqlite3_backup object records state information about an ongoing 6957** online backup operation. ^The sqlite3_backup object is created by 6958** a call to [sqlite3_backup_init()] and is destroyed by a call to 6959** [sqlite3_backup_finish()]. 6960** 6961** See Also: [Using the SQLite Online Backup API] 6962*/ 6963typedef struct sqlite3_backup sqlite3_backup; 6964 6965/* 6966** CAPI3REF: Online Backup API. 6967** 6968** The backup API copies the content of one database into another. 6969** It is useful either for creating backups of databases or 6970** for copying in-memory databases to or from persistent files. 6971** 6972** See Also: [Using the SQLite Online Backup API] 6973** 6974** ^SQLite holds a write transaction open on the destination database file 6975** for the duration of the backup operation. 6976** ^The source database is read-locked only while it is being read; 6977** it is not locked continuously for the entire backup operation. 6978** ^Thus, the backup may be performed on a live source database without 6979** preventing other database connections from 6980** reading or writing to the source database while the backup is underway. 6981** 6982** ^(To perform a backup operation: 6983** <ol> 6984** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6985** backup, 6986** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6987** the data between the two databases, and finally 6988** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6989** associated with the backup operation. 6990** </ol>)^ 6991** There should be exactly one call to sqlite3_backup_finish() for each 6992** successful call to sqlite3_backup_init(). 6993** 6994** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6995** 6996** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6997** [database connection] associated with the destination database 6998** and the database name, respectively. 6999** ^The database name is "main" for the main database, "temp" for the 7000** temporary database, or the name specified after the AS keyword in 7001** an [ATTACH] statement for an attached database. 7002** ^The S and M arguments passed to 7003** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7004** and database name of the source database, respectively. 7005** ^The source and destination [database connections] (parameters S and D) 7006** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7007** an error. 7008** 7009** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if 7010** there is already a read or read-write transaction open on the 7011** destination database. 7012** 7013** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7014** returned and an error code and error message are stored in the 7015** destination [database connection] D. 7016** ^The error code and message for the failed call to sqlite3_backup_init() 7017** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7018** [sqlite3_errmsg16()] functions. 7019** ^A successful call to sqlite3_backup_init() returns a pointer to an 7020** [sqlite3_backup] object. 7021** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7022** sqlite3_backup_finish() functions to perform the specified backup 7023** operation. 7024** 7025** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7026** 7027** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7028** the source and destination databases specified by [sqlite3_backup] object B. 7029** ^If N is negative, all remaining source pages are copied. 7030** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7031** are still more pages to be copied, then the function returns [SQLITE_OK]. 7032** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7033** from source to destination, then it returns [SQLITE_DONE]. 7034** ^If an error occurs while running sqlite3_backup_step(B,N), 7035** then an [error code] is returned. ^As well as [SQLITE_OK] and 7036** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7037** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7038** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7039** 7040** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7041** <ol> 7042** <li> the destination database was opened read-only, or 7043** <li> the destination database is using write-ahead-log journaling 7044** and the destination and source page sizes differ, or 7045** <li> the destination database is an in-memory database and the 7046** destination and source page sizes differ. 7047** </ol>)^ 7048** 7049** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7050** the [sqlite3_busy_handler | busy-handler function] 7051** is invoked (if one is specified). ^If the 7052** busy-handler returns non-zero before the lock is available, then 7053** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7054** sqlite3_backup_step() can be retried later. ^If the source 7055** [database connection] 7056** is being used to write to the source database when sqlite3_backup_step() 7057** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7058** case the call to sqlite3_backup_step() can be retried later on. ^(If 7059** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7060** [SQLITE_READONLY] is returned, then 7061** there is no point in retrying the call to sqlite3_backup_step(). These 7062** errors are considered fatal.)^ The application must accept 7063** that the backup operation has failed and pass the backup operation handle 7064** to the sqlite3_backup_finish() to release associated resources. 7065** 7066** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7067** on the destination file. ^The exclusive lock is not released until either 7068** sqlite3_backup_finish() is called or the backup operation is complete 7069** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7070** sqlite3_backup_step() obtains a [shared lock] on the source database that 7071** lasts for the duration of the sqlite3_backup_step() call. 7072** ^Because the source database is not locked between calls to 7073** sqlite3_backup_step(), the source database may be modified mid-way 7074** through the backup process. ^If the source database is modified by an 7075** external process or via a database connection other than the one being 7076** used by the backup operation, then the backup will be automatically 7077** restarted by the next call to sqlite3_backup_step(). ^If the source 7078** database is modified by the using the same database connection as is used 7079** by the backup operation, then the backup database is automatically 7080** updated at the same time. 7081** 7082** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7083** 7084** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7085** application wishes to abandon the backup operation, the application 7086** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7087** ^The sqlite3_backup_finish() interfaces releases all 7088** resources associated with the [sqlite3_backup] object. 7089** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7090** active write-transaction on the destination database is rolled back. 7091** The [sqlite3_backup] object is invalid 7092** and may not be used following a call to sqlite3_backup_finish(). 7093** 7094** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7095** sqlite3_backup_step() errors occurred, regardless or whether or not 7096** sqlite3_backup_step() completed. 7097** ^If an out-of-memory condition or IO error occurred during any prior 7098** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7099** sqlite3_backup_finish() returns the corresponding [error code]. 7100** 7101** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7102** is not a permanent error and does not affect the return value of 7103** sqlite3_backup_finish(). 7104** 7105** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7106** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7107** 7108** ^The sqlite3_backup_remaining() routine returns the number of pages still 7109** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7110** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7111** in the source database at the conclusion of the most recent 7112** sqlite3_backup_step(). 7113** ^(The values returned by these functions are only updated by 7114** sqlite3_backup_step(). If the source database is modified in a way that 7115** changes the size of the source database or the number of pages remaining, 7116** those changes are not reflected in the output of sqlite3_backup_pagecount() 7117** and sqlite3_backup_remaining() until after the next 7118** sqlite3_backup_step().)^ 7119** 7120** <b>Concurrent Usage of Database Handles</b> 7121** 7122** ^The source [database connection] may be used by the application for other 7123** purposes while a backup operation is underway or being initialized. 7124** ^If SQLite is compiled and configured to support threadsafe database 7125** connections, then the source database connection may be used concurrently 7126** from within other threads. 7127** 7128** However, the application must guarantee that the destination 7129** [database connection] is not passed to any other API (by any thread) after 7130** sqlite3_backup_init() is called and before the corresponding call to 7131** sqlite3_backup_finish(). SQLite does not currently check to see 7132** if the application incorrectly accesses the destination [database connection] 7133** and so no error code is reported, but the operations may malfunction 7134** nevertheless. Use of the destination database connection while a 7135** backup is in progress might also also cause a mutex deadlock. 7136** 7137** If running in [shared cache mode], the application must 7138** guarantee that the shared cache used by the destination database 7139** is not accessed while the backup is running. In practice this means 7140** that the application must guarantee that the disk file being 7141** backed up to is not accessed by any connection within the process, 7142** not just the specific connection that was passed to sqlite3_backup_init(). 7143** 7144** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7145** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7146** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7147** APIs are not strictly speaking threadsafe. If they are invoked at the 7148** same time as another thread is invoking sqlite3_backup_step() it is 7149** possible that they return invalid values. 7150*/ 7151SQLITE_API sqlite3_backup *SQLITE_STDCALL sqlite3_backup_init( 7152 sqlite3 *pDest, /* Destination database handle */ 7153 const char *zDestName, /* Destination database name */ 7154 sqlite3 *pSource, /* Source database handle */ 7155 const char *zSourceName /* Source database name */ 7156); 7157SQLITE_API int SQLITE_STDCALL sqlite3_backup_step(sqlite3_backup *p, int nPage); 7158SQLITE_API int SQLITE_STDCALL sqlite3_backup_finish(sqlite3_backup *p); 7159SQLITE_API int SQLITE_STDCALL sqlite3_backup_remaining(sqlite3_backup *p); 7160SQLITE_API int SQLITE_STDCALL sqlite3_backup_pagecount(sqlite3_backup *p); 7161 7162/* 7163** CAPI3REF: Unlock Notification 7164** METHOD: sqlite3 7165** 7166** ^When running in shared-cache mode, a database operation may fail with 7167** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7168** individual tables within the shared-cache cannot be obtained. See 7169** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7170** ^This API may be used to register a callback that SQLite will invoke 7171** when the connection currently holding the required lock relinquishes it. 7172** ^This API is only available if the library was compiled with the 7173** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7174** 7175** See Also: [Using the SQLite Unlock Notification Feature]. 7176** 7177** ^Shared-cache locks are released when a database connection concludes 7178** its current transaction, either by committing it or rolling it back. 7179** 7180** ^When a connection (known as the blocked connection) fails to obtain a 7181** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7182** identity of the database connection (the blocking connection) that 7183** has locked the required resource is stored internally. ^After an 7184** application receives an SQLITE_LOCKED error, it may call the 7185** sqlite3_unlock_notify() method with the blocked connection handle as 7186** the first argument to register for a callback that will be invoked 7187** when the blocking connections current transaction is concluded. ^The 7188** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7189** call that concludes the blocking connections transaction. 7190** 7191** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7192** there is a chance that the blocking connection will have already 7193** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7194** If this happens, then the specified callback is invoked immediately, 7195** from within the call to sqlite3_unlock_notify().)^ 7196** 7197** ^If the blocked connection is attempting to obtain a write-lock on a 7198** shared-cache table, and more than one other connection currently holds 7199** a read-lock on the same table, then SQLite arbitrarily selects one of 7200** the other connections to use as the blocking connection. 7201** 7202** ^(There may be at most one unlock-notify callback registered by a 7203** blocked connection. If sqlite3_unlock_notify() is called when the 7204** blocked connection already has a registered unlock-notify callback, 7205** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7206** called with a NULL pointer as its second argument, then any existing 7207** unlock-notify callback is canceled. ^The blocked connections 7208** unlock-notify callback may also be canceled by closing the blocked 7209** connection using [sqlite3_close()]. 7210** 7211** The unlock-notify callback is not reentrant. If an application invokes 7212** any sqlite3_xxx API functions from within an unlock-notify callback, a 7213** crash or deadlock may be the result. 7214** 7215** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7216** returns SQLITE_OK. 7217** 7218** <b>Callback Invocation Details</b> 7219** 7220** When an unlock-notify callback is registered, the application provides a 7221** single void* pointer that is passed to the callback when it is invoked. 7222** However, the signature of the callback function allows SQLite to pass 7223** it an array of void* context pointers. The first argument passed to 7224** an unlock-notify callback is a pointer to an array of void* pointers, 7225** and the second is the number of entries in the array. 7226** 7227** When a blocking connections transaction is concluded, there may be 7228** more than one blocked connection that has registered for an unlock-notify 7229** callback. ^If two or more such blocked connections have specified the 7230** same callback function, then instead of invoking the callback function 7231** multiple times, it is invoked once with the set of void* context pointers 7232** specified by the blocked connections bundled together into an array. 7233** This gives the application an opportunity to prioritize any actions 7234** related to the set of unblocked database connections. 7235** 7236** <b>Deadlock Detection</b> 7237** 7238** Assuming that after registering for an unlock-notify callback a 7239** database waits for the callback to be issued before taking any further 7240** action (a reasonable assumption), then using this API may cause the 7241** application to deadlock. For example, if connection X is waiting for 7242** connection Y's transaction to be concluded, and similarly connection 7243** Y is waiting on connection X's transaction, then neither connection 7244** will proceed and the system may remain deadlocked indefinitely. 7245** 7246** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7247** detection. ^If a given call to sqlite3_unlock_notify() would put the 7248** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7249** unlock-notify callback is registered. The system is said to be in 7250** a deadlocked state if connection A has registered for an unlock-notify 7251** callback on the conclusion of connection B's transaction, and connection 7252** B has itself registered for an unlock-notify callback when connection 7253** A's transaction is concluded. ^Indirect deadlock is also detected, so 7254** the system is also considered to be deadlocked if connection B has 7255** registered for an unlock-notify callback on the conclusion of connection 7256** C's transaction, where connection C is waiting on connection A. ^Any 7257** number of levels of indirection are allowed. 7258** 7259** <b>The "DROP TABLE" Exception</b> 7260** 7261** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7262** always appropriate to call sqlite3_unlock_notify(). There is however, 7263** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7264** SQLite checks if there are any currently executing SELECT statements 7265** that belong to the same connection. If there are, SQLITE_LOCKED is 7266** returned. In this case there is no "blocking connection", so invoking 7267** sqlite3_unlock_notify() results in the unlock-notify callback being 7268** invoked immediately. If the application then re-attempts the "DROP TABLE" 7269** or "DROP INDEX" query, an infinite loop might be the result. 7270** 7271** One way around this problem is to check the extended error code returned 7272** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7273** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7274** the special "DROP TABLE/INDEX" case, the extended error code is just 7275** SQLITE_LOCKED.)^ 7276*/ 7277SQLITE_API int SQLITE_STDCALL sqlite3_unlock_notify( 7278 sqlite3 *pBlocked, /* Waiting connection */ 7279 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7280 void *pNotifyArg /* Argument to pass to xNotify */ 7281); 7282 7283 7284/* 7285** CAPI3REF: String Comparison 7286** 7287** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7288** and extensions to compare the contents of two buffers containing UTF-8 7289** strings in a case-independent fashion, using the same definition of "case 7290** independence" that SQLite uses internally when comparing identifiers. 7291*/ 7292SQLITE_API int SQLITE_STDCALL sqlite3_stricmp(const char *, const char *); 7293SQLITE_API int SQLITE_STDCALL sqlite3_strnicmp(const char *, const char *, int); 7294 7295/* 7296** CAPI3REF: String Globbing 7297* 7298** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches 7299** the glob pattern P, and it returns non-zero if string X does not match 7300** the glob pattern P. ^The definition of glob pattern matching used in 7301** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7302** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case 7303** sensitive. 7304** 7305** Note that this routine returns zero on a match and non-zero if the strings 7306** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7307*/ 7308SQLITE_API int SQLITE_STDCALL sqlite3_strglob(const char *zGlob, const char *zStr); 7309 7310/* 7311** CAPI3REF: Error Logging Interface 7312** 7313** ^The [sqlite3_log()] interface writes a message into the [error log] 7314** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7315** ^If logging is enabled, the zFormat string and subsequent arguments are 7316** used with [sqlite3_snprintf()] to generate the final output string. 7317** 7318** The sqlite3_log() interface is intended for use by extensions such as 7319** virtual tables, collating functions, and SQL functions. While there is 7320** nothing to prevent an application from calling sqlite3_log(), doing so 7321** is considered bad form. 7322** 7323** The zFormat string must not be NULL. 7324** 7325** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7326** will not use dynamically allocated memory. The log message is stored in 7327** a fixed-length buffer on the stack. If the log message is longer than 7328** a few hundred characters, it will be truncated to the length of the 7329** buffer. 7330*/ 7331SQLITE_API void SQLITE_CDECL sqlite3_log(int iErrCode, const char *zFormat, ...); 7332 7333/* 7334** CAPI3REF: Write-Ahead Log Commit Hook 7335** METHOD: sqlite3 7336** 7337** ^The [sqlite3_wal_hook()] function is used to register a callback that 7338** is invoked each time data is committed to a database in wal mode. 7339** 7340** ^(The callback is invoked by SQLite after the commit has taken place and 7341** the associated write-lock on the database released)^, so the implementation 7342** may read, write or [checkpoint] the database as required. 7343** 7344** ^The first parameter passed to the callback function when it is invoked 7345** is a copy of the third parameter passed to sqlite3_wal_hook() when 7346** registering the callback. ^The second is a copy of the database handle. 7347** ^The third parameter is the name of the database that was written to - 7348** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7349** is the number of pages currently in the write-ahead log file, 7350** including those that were just committed. 7351** 7352** The callback function should normally return [SQLITE_OK]. ^If an error 7353** code is returned, that error will propagate back up through the 7354** SQLite code base to cause the statement that provoked the callback 7355** to report an error, though the commit will have still occurred. If the 7356** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7357** that does not correspond to any valid SQLite error code, the results 7358** are undefined. 7359** 7360** A single database handle may have at most a single write-ahead log callback 7361** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7362** previously registered write-ahead log callback. ^Note that the 7363** [sqlite3_wal_autocheckpoint()] interface and the 7364** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7365** those overwrite any prior [sqlite3_wal_hook()] settings. 7366*/ 7367SQLITE_API void *SQLITE_STDCALL sqlite3_wal_hook( 7368 sqlite3*, 7369 int(*)(void *,sqlite3*,const char*,int), 7370 void* 7371); 7372 7373/* 7374** CAPI3REF: Configure an auto-checkpoint 7375** METHOD: sqlite3 7376** 7377** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 7378** [sqlite3_wal_hook()] that causes any database on [database connection] D 7379** to automatically [checkpoint] 7380** after committing a transaction if there are N or 7381** more frames in the [write-ahead log] file. ^Passing zero or 7382** a negative value as the nFrame parameter disables automatic 7383** checkpoints entirely. 7384** 7385** ^The callback registered by this function replaces any existing callback 7386** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 7387** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 7388** configured by this function. 7389** 7390** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 7391** from SQL. 7392** 7393** ^Checkpoints initiated by this mechanism are 7394** [sqlite3_wal_checkpoint_v2|PASSIVE]. 7395** 7396** ^Every new [database connection] defaults to having the auto-checkpoint 7397** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 7398** pages. The use of this interface 7399** is only necessary if the default setting is found to be suboptimal 7400** for a particular application. 7401*/ 7402SQLITE_API int SQLITE_STDCALL sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 7403 7404/* 7405** CAPI3REF: Checkpoint a database 7406** METHOD: sqlite3 7407** 7408** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 7409** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 7410** 7411** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 7412** [write-ahead log] for database X on [database connection] D to be 7413** transferred into the database file and for the write-ahead log to 7414** be reset. See the [checkpointing] documentation for addition 7415** information. 7416** 7417** This interface used to be the only way to cause a checkpoint to 7418** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 7419** interface was added. This interface is retained for backwards 7420** compatibility and as a convenience for applications that need to manually 7421** start a callback but which do not need the full power (and corresponding 7422** complication) of [sqlite3_wal_checkpoint_v2()]. 7423*/ 7424SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 7425 7426/* 7427** CAPI3REF: Checkpoint a database 7428** METHOD: sqlite3 7429** 7430** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 7431** operation on database X of [database connection] D in mode M. Status 7432** information is written back into integers pointed to by L and C.)^ 7433** ^(The M parameter must be a valid [checkpoint mode]:)^ 7434** 7435** <dl> 7436** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7437** ^Checkpoint as many frames as possible without waiting for any database 7438** readers or writers to finish, then sync the database file if all frames 7439** in the log were checkpointed. ^The [busy-handler callback] 7440** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 7441** ^On the other hand, passive mode might leave the checkpoint unfinished 7442** if there are concurrent readers or writers. 7443** 7444** <dt>SQLITE_CHECKPOINT_FULL<dd> 7445** ^This mode blocks (it invokes the 7446** [sqlite3_busy_handler|busy-handler callback]) until there is no 7447** database writer and all readers are reading from the most recent database 7448** snapshot. ^It then checkpoints all frames in the log file and syncs the 7449** database file. ^This mode blocks new database writers while it is pending, 7450** but new database readers are allowed to continue unimpeded. 7451** 7452** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7453** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 7454** that after checkpointing the log file it blocks (calls the 7455** [busy-handler callback]) 7456** until all readers are reading from the database file only. ^This ensures 7457** that the next writer will restart the log file from the beginning. 7458** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 7459** database writer attempts while it is pending, but does not impede readers. 7460** 7461** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 7462** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 7463** addition that it also truncates the log file to zero bytes just prior 7464** to a successful return. 7465** </dl> 7466** 7467** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 7468** the log file or to -1 if the checkpoint could not run because 7469** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 7470** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 7471** log file (including any that were already checkpointed before the function 7472** was called) or to -1 if the checkpoint could not run due to an error or 7473** because the database is not in WAL mode. ^Note that upon successful 7474** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 7475** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 7476** 7477** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 7478** any other process is running a checkpoint operation at the same time, the 7479** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 7480** busy-handler configured, it will not be invoked in this case. 7481** 7482** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 7483** exclusive "writer" lock on the database file. ^If the writer lock cannot be 7484** obtained immediately, and a busy-handler is configured, it is invoked and 7485** the writer lock retried until either the busy-handler returns 0 or the lock 7486** is successfully obtained. ^The busy-handler is also invoked while waiting for 7487** database readers as described above. ^If the busy-handler returns 0 before 7488** the writer lock is obtained or while waiting for database readers, the 7489** checkpoint operation proceeds from that point in the same way as 7490** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7491** without blocking any further. ^SQLITE_BUSY is returned in this case. 7492** 7493** ^If parameter zDb is NULL or points to a zero length string, then the 7494** specified operation is attempted on all WAL databases [attached] to 7495** [database connection] db. In this case the 7496** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 7497** an SQLITE_BUSY error is encountered when processing one or more of the 7498** attached WAL databases, the operation is still attempted on any remaining 7499** attached databases and SQLITE_BUSY is returned at the end. ^If any other 7500** error occurs while processing an attached database, processing is abandoned 7501** and the error code is returned to the caller immediately. ^If no error 7502** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7503** databases, SQLITE_OK is returned. 7504** 7505** ^If database zDb is the name of an attached database that is not in WAL 7506** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 7507** zDb is not NULL (or a zero length string) and is not the name of any 7508** attached database, SQLITE_ERROR is returned to the caller. 7509** 7510** ^Unless it returns SQLITE_MISUSE, 7511** the sqlite3_wal_checkpoint_v2() interface 7512** sets the error information that is queried by 7513** [sqlite3_errcode()] and [sqlite3_errmsg()]. 7514** 7515** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 7516** from SQL. 7517*/ 7518SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint_v2( 7519 sqlite3 *db, /* Database handle */ 7520 const char *zDb, /* Name of attached database (or NULL) */ 7521 int eMode, /* SQLITE_CHECKPOINT_* value */ 7522 int *pnLog, /* OUT: Size of WAL log in frames */ 7523 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7524); 7525 7526/* 7527** CAPI3REF: Checkpoint Mode Values 7528** KEYWORDS: {checkpoint mode} 7529** 7530** These constants define all valid values for the "checkpoint mode" passed 7531** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 7532** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 7533** meaning of each of these checkpoint modes. 7534*/ 7535#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 7536#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 7537#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 7538#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 7539 7540/* 7541** CAPI3REF: Virtual Table Interface Configuration 7542** 7543** This function may be called by either the [xConnect] or [xCreate] method 7544** of a [virtual table] implementation to configure 7545** various facets of the virtual table interface. 7546** 7547** If this interface is invoked outside the context of an xConnect or 7548** xCreate virtual table method then the behavior is undefined. 7549** 7550** At present, there is only one option that may be configured using 7551** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7552** may be added in the future. 7553*/ 7554SQLITE_API int SQLITE_CDECL sqlite3_vtab_config(sqlite3*, int op, ...); 7555 7556/* 7557** CAPI3REF: Virtual Table Configuration Options 7558** 7559** These macros define the various options to the 7560** [sqlite3_vtab_config()] interface that [virtual table] implementations 7561** can use to customize and optimize their behavior. 7562** 7563** <dl> 7564** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7565** <dd>Calls of the form 7566** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7567** where X is an integer. If X is zero, then the [virtual table] whose 7568** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7569** support constraints. In this configuration (which is the default) if 7570** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7571** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7572** specified as part of the users SQL statement, regardless of the actual 7573** ON CONFLICT mode specified. 7574** 7575** If X is non-zero, then the virtual table implementation guarantees 7576** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7577** any modifications to internal or persistent data structures have been made. 7578** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7579** is able to roll back a statement or database transaction, and abandon 7580** or continue processing the current SQL statement as appropriate. 7581** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7582** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7583** had been ABORT. 7584** 7585** Virtual table implementations that are required to handle OR REPLACE 7586** must do so within the [xUpdate] method. If a call to the 7587** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7588** CONFLICT policy is REPLACE, the virtual table implementation should 7589** silently replace the appropriate rows within the xUpdate callback and 7590** return SQLITE_OK. Or, if this is not possible, it may return 7591** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7592** constraint handling. 7593** </dl> 7594*/ 7595#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7596 7597/* 7598** CAPI3REF: Determine The Virtual Table Conflict Policy 7599** 7600** This function may only be called from within a call to the [xUpdate] method 7601** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7602** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7603** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7604** of the SQL statement that triggered the call to the [xUpdate] method of the 7605** [virtual table]. 7606*/ 7607SQLITE_API int SQLITE_STDCALL sqlite3_vtab_on_conflict(sqlite3 *); 7608 7609/* 7610** CAPI3REF: Conflict resolution modes 7611** KEYWORDS: {conflict resolution mode} 7612** 7613** These constants are returned by [sqlite3_vtab_on_conflict()] to 7614** inform a [virtual table] implementation what the [ON CONFLICT] mode 7615** is for the SQL statement being evaluated. 7616** 7617** Note that the [SQLITE_IGNORE] constant is also used as a potential 7618** return value from the [sqlite3_set_authorizer()] callback and that 7619** [SQLITE_ABORT] is also a [result code]. 7620*/ 7621#define SQLITE_ROLLBACK 1 7622/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7623#define SQLITE_FAIL 3 7624/* #define SQLITE_ABORT 4 // Also an error code */ 7625#define SQLITE_REPLACE 5 7626 7627/* 7628** CAPI3REF: Prepared Statement Scan Status Opcodes 7629** KEYWORDS: {scanstatus options} 7630** 7631** The following constants can be used for the T parameter to the 7632** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 7633** different metric for sqlite3_stmt_scanstatus() to return. 7634** 7635** When the value returned to V is a string, space to hold that string is 7636** managed by the prepared statement S and will be automatically freed when 7637** S is finalized. 7638** 7639** <dl> 7640** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 7641** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 7642** set to the total number of times that the X-th loop has run.</dd> 7643** 7644** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 7645** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 7646** to the total number of rows examined by all iterations of the X-th loop.</dd> 7647** 7648** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 7649** <dd>^The "double" variable pointed to by the T parameter will be set to the 7650** query planner's estimate for the average number of rows output from each 7651** iteration of the X-th loop. If the query planner's estimates was accurate, 7652** then this value will approximate the quotient NVISIT/NLOOP and the 7653** product of this value for all prior loops with the same SELECTID will 7654** be the NLOOP value for the current loop. 7655** 7656** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 7657** <dd>^The "const char *" variable pointed to by the T parameter will be set 7658** to a zero-terminated UTF-8 string containing the name of the index or table 7659** used for the X-th loop. 7660** 7661** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 7662** <dd>^The "const char *" variable pointed to by the T parameter will be set 7663** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 7664** description for the X-th loop. 7665** 7666** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 7667** <dd>^The "int" variable pointed to by the T parameter will be set to the 7668** "select-id" for the X-th loop. The select-id identifies which query or 7669** subquery the loop is part of. The main query has a select-id of zero. 7670** The select-id is the same value as is output in the first column 7671** of an [EXPLAIN QUERY PLAN] query. 7672** </dl> 7673*/ 7674#define SQLITE_SCANSTAT_NLOOP 0 7675#define SQLITE_SCANSTAT_NVISIT 1 7676#define SQLITE_SCANSTAT_EST 2 7677#define SQLITE_SCANSTAT_NAME 3 7678#define SQLITE_SCANSTAT_EXPLAIN 4 7679#define SQLITE_SCANSTAT_SELECTID 5 7680 7681/* 7682** CAPI3REF: Prepared Statement Scan Status 7683** METHOD: sqlite3_stmt 7684** 7685** This interface returns information about the predicted and measured 7686** performance for pStmt. Advanced applications can use this 7687** interface to compare the predicted and the measured performance and 7688** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 7689** 7690** Since this interface is expected to be rarely used, it is only 7691** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 7692** compile-time option. 7693** 7694** The "iScanStatusOp" parameter determines which status information to return. 7695** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 7696** of this interface is undefined. 7697** ^The requested measurement is written into a variable pointed to by 7698** the "pOut" parameter. 7699** Parameter "idx" identifies the specific loop to retrieve statistics for. 7700** Loops are numbered starting from zero. ^If idx is out of range - less than 7701** zero or greater than or equal to the total number of loops used to implement 7702** the statement - a non-zero value is returned and the variable that pOut 7703** points to is unchanged. 7704** 7705** ^Statistics might not be available for all loops in all statements. ^In cases 7706** where there exist loops with no available statistics, this function behaves 7707** as if the loop did not exist - it returns non-zero and leave the variable 7708** that pOut points to unchanged. 7709** 7710** See also: [sqlite3_stmt_scanstatus_reset()] 7711*/ 7712SQLITE_API int SQLITE_STDCALL sqlite3_stmt_scanstatus( 7713 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 7714 int idx, /* Index of loop to report on */ 7715 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 7716 void *pOut /* Result written here */ 7717); 7718 7719/* 7720** CAPI3REF: Zero Scan-Status Counters 7721** METHOD: sqlite3_stmt 7722** 7723** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 7724** 7725** This API is only available if the library is built with pre-processor 7726** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 7727*/ 7728SQLITE_API void SQLITE_STDCALL sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 7729 7730 7731/* 7732** Undo the hack that converts floating point types to integer for 7733** builds on processors without floating point support. 7734*/ 7735#ifdef SQLITE_OMIT_FLOATING_POINT 7736# undef double 7737#endif 7738 7739#ifdef __cplusplus 7740} /* End of the 'extern "C"' block */ 7741#endif 7742#endif /* _SQLITE3_H_ */ 7743 7744/* 7745** 2010 August 30 7746** 7747** The author disclaims copyright to this source code. In place of 7748** a legal notice, here is a blessing: 7749** 7750** May you do good and not evil. 7751** May you find forgiveness for yourself and forgive others. 7752** May you share freely, never taking more than you give. 7753** 7754************************************************************************* 7755*/ 7756 7757#ifndef _SQLITE3RTREE_H_ 7758#define _SQLITE3RTREE_H_ 7759 7760 7761#ifdef __cplusplus 7762extern "C" { 7763#endif 7764 7765typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry; 7766typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info; 7767 7768/* The double-precision datatype used by RTree depends on the 7769** SQLITE_RTREE_INT_ONLY compile-time option. 7770*/ 7771#ifdef SQLITE_RTREE_INT_ONLY 7772 typedef sqlite3_int64 sqlite3_rtree_dbl; 7773#else 7774 typedef double sqlite3_rtree_dbl; 7775#endif 7776 7777/* 7778** Register a geometry callback named zGeom that can be used as part of an 7779** R-Tree geometry query as follows: 7780** 7781** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...) 7782*/ 7783SQLITE_API int SQLITE_STDCALL sqlite3_rtree_geometry_callback( 7784 sqlite3 *db, 7785 const char *zGeom, 7786 int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*), 7787 void *pContext 7788); 7789 7790 7791/* 7792** A pointer to a structure of the following type is passed as the first 7793** argument to callbacks registered using rtree_geometry_callback(). 7794*/ 7795struct sqlite3_rtree_geometry { 7796 void *pContext; /* Copy of pContext passed to s_r_g_c() */ 7797 int nParam; /* Size of array aParam[] */ 7798 sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */ 7799 void *pUser; /* Callback implementation user data */ 7800 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */ 7801}; 7802 7803/* 7804** Register a 2nd-generation geometry callback named zScore that can be 7805** used as part of an R-Tree geometry query as follows: 7806** 7807** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...) 7808*/ 7809SQLITE_API int SQLITE_STDCALL sqlite3_rtree_query_callback( 7810 sqlite3 *db, 7811 const char *zQueryFunc, 7812 int (*xQueryFunc)(sqlite3_rtree_query_info*), 7813 void *pContext, 7814 void (*xDestructor)(void*) 7815); 7816 7817 7818/* 7819** A pointer to a structure of the following type is passed as the 7820** argument to scored geometry callback registered using 7821** sqlite3_rtree_query_callback(). 7822** 7823** Note that the first 5 fields of this structure are identical to 7824** sqlite3_rtree_geometry. This structure is a subclass of 7825** sqlite3_rtree_geometry. 7826*/ 7827struct sqlite3_rtree_query_info { 7828 void *pContext; /* pContext from when function registered */ 7829 int nParam; /* Number of function parameters */ 7830 sqlite3_rtree_dbl *aParam; /* value of function parameters */ 7831 void *pUser; /* callback can use this, if desired */ 7832 void (*xDelUser)(void*); /* function to free pUser */ 7833 sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */ 7834 unsigned int *anQueue; /* Number of pending entries in the queue */ 7835 int nCoord; /* Number of coordinates */ 7836 int iLevel; /* Level of current node or entry */ 7837 int mxLevel; /* The largest iLevel value in the tree */ 7838 sqlite3_int64 iRowid; /* Rowid for current entry */ 7839 sqlite3_rtree_dbl rParentScore; /* Score of parent node */ 7840 int eParentWithin; /* Visibility of parent node */ 7841 int eWithin; /* OUT: Visiblity */ 7842 sqlite3_rtree_dbl rScore; /* OUT: Write the score here */ 7843 /* The following fields are only available in 3.8.11 and later */ 7844 sqlite3_value **apSqlParam; /* Original SQL values of parameters */ 7845}; 7846 7847/* 7848** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin. 7849*/ 7850#define NOT_WITHIN 0 /* Object completely outside of query region */ 7851#define PARTLY_WITHIN 1 /* Object partially overlaps query region */ 7852#define FULLY_WITHIN 2 /* Object fully contained within query region */ 7853 7854 7855#ifdef __cplusplus 7856} /* end of the 'extern "C"' block */ 7857#endif 7858 7859#endif /* ifndef _SQLITE3RTREE_H_ */ 7860 7861