sqlite3.h revision 282328
1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are suppose to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef _SQLITE3_H_ 34#define _SQLITE3_H_ 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_STDCALL 58# define SQLITE_STDCALL 59#endif 60 61/* 62** These no-op macros are used in front of interfaces to mark those 63** interfaces as either deprecated or experimental. New applications 64** should not use deprecated interfaces - they are supported for backwards 65** compatibility only. Application writers should be aware that 66** experimental interfaces are subject to change in point releases. 67** 68** These macros used to resolve to various kinds of compiler magic that 69** would generate warning messages when they were used. But that 70** compiler magic ended up generating such a flurry of bug reports 71** that we have taken it all out and gone back to using simple 72** noop macros. 73*/ 74#define SQLITE_DEPRECATED 75#define SQLITE_EXPERIMENTAL 76 77/* 78** Ensure these symbols were not defined by some previous header file. 79*/ 80#ifdef SQLITE_VERSION 81# undef SQLITE_VERSION 82#endif 83#ifdef SQLITE_VERSION_NUMBER 84# undef SQLITE_VERSION_NUMBER 85#endif 86 87/* 88** CAPI3REF: Compile-Time Library Version Numbers 89** 90** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 91** evaluates to a string literal that is the SQLite version in the 92** format "X.Y.Z" where X is the major version number (always 3 for 93** SQLite3) and Y is the minor version number and Z is the release number.)^ 94** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 95** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 96** numbers used in [SQLITE_VERSION].)^ 97** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 98** be larger than the release from which it is derived. Either Y will 99** be held constant and Z will be incremented or else Y will be incremented 100** and Z will be reset to zero. 101** 102** Since version 3.6.18, SQLite source code has been stored in the 103** <a href="http://www.fossil-scm.org/">Fossil configuration management 104** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 105** a string which identifies a particular check-in of SQLite 106** within its configuration management system. ^The SQLITE_SOURCE_ID 107** string contains the date and time of the check-in (UTC) and an SHA1 108** hash of the entire source tree. 109** 110** See also: [sqlite3_libversion()], 111** [sqlite3_libversion_number()], [sqlite3_sourceid()], 112** [sqlite_version()] and [sqlite_source_id()]. 113*/ 114#define SQLITE_VERSION "3.8.9" 115#define SQLITE_VERSION_NUMBER 3008009 116#define SQLITE_SOURCE_ID "2015-04-08 12:16:33 8a8ffc862e96f57aa698f93de10dee28e69f6e09" 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** 274** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 275** for the [sqlite3] object. 276** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 277** the [sqlite3] object is successfully destroyed and all associated 278** resources are deallocated. 279** 280** ^If the database connection is associated with unfinalized prepared 281** statements or unfinished sqlite3_backup objects then sqlite3_close() 282** will leave the database connection open and return [SQLITE_BUSY]. 283** ^If sqlite3_close_v2() is called with unfinalized prepared statements 284** and/or unfinished sqlite3_backups, then the database connection becomes 285** an unusable "zombie" which will automatically be deallocated when the 286** last prepared statement is finalized or the last sqlite3_backup is 287** finished. The sqlite3_close_v2() interface is intended for use with 288** host languages that are garbage collected, and where the order in which 289** destructors are called is arbitrary. 290** 291** Applications should [sqlite3_finalize | finalize] all [prepared statements], 292** [sqlite3_blob_close | close] all [BLOB handles], and 293** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 294** with the [sqlite3] object prior to attempting to close the object. ^If 295** sqlite3_close_v2() is called on a [database connection] that still has 296** outstanding [prepared statements], [BLOB handles], and/or 297** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 298** of resources is deferred until all [prepared statements], [BLOB handles], 299** and [sqlite3_backup] objects are also destroyed. 300** 301** ^If an [sqlite3] object is destroyed while a transaction is open, 302** the transaction is automatically rolled back. 303** 304** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 305** must be either a NULL 306** pointer or an [sqlite3] object pointer obtained 307** from [sqlite3_open()], [sqlite3_open16()], or 308** [sqlite3_open_v2()], and not previously closed. 309** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 310** argument is a harmless no-op. 311*/ 312SQLITE_API int SQLITE_STDCALL sqlite3_close(sqlite3*); 313SQLITE_API int SQLITE_STDCALL sqlite3_close_v2(sqlite3*); 314 315/* 316** The type for a callback function. 317** This is legacy and deprecated. It is included for historical 318** compatibility and is not documented. 319*/ 320typedef int (*sqlite3_callback)(void*,int,char**, char**); 321 322/* 323** CAPI3REF: One-Step Query Execution Interface 324** 325** The sqlite3_exec() interface is a convenience wrapper around 326** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 327** that allows an application to run multiple statements of SQL 328** without having to use a lot of C code. 329** 330** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 331** semicolon-separate SQL statements passed into its 2nd argument, 332** in the context of the [database connection] passed in as its 1st 333** argument. ^If the callback function of the 3rd argument to 334** sqlite3_exec() is not NULL, then it is invoked for each result row 335** coming out of the evaluated SQL statements. ^The 4th argument to 336** sqlite3_exec() is relayed through to the 1st argument of each 337** callback invocation. ^If the callback pointer to sqlite3_exec() 338** is NULL, then no callback is ever invoked and result rows are 339** ignored. 340** 341** ^If an error occurs while evaluating the SQL statements passed into 342** sqlite3_exec(), then execution of the current statement stops and 343** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 344** is not NULL then any error message is written into memory obtained 345** from [sqlite3_malloc()] and passed back through the 5th parameter. 346** To avoid memory leaks, the application should invoke [sqlite3_free()] 347** on error message strings returned through the 5th parameter of 348** of sqlite3_exec() after the error message string is no longer needed. 349** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 350** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 351** NULL before returning. 352** 353** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 354** routine returns SQLITE_ABORT without invoking the callback again and 355** without running any subsequent SQL statements. 356** 357** ^The 2nd argument to the sqlite3_exec() callback function is the 358** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 359** callback is an array of pointers to strings obtained as if from 360** [sqlite3_column_text()], one for each column. ^If an element of a 361** result row is NULL then the corresponding string pointer for the 362** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 363** sqlite3_exec() callback is an array of pointers to strings where each 364** entry represents the name of corresponding result column as obtained 365** from [sqlite3_column_name()]. 366** 367** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 368** to an empty string, or a pointer that contains only whitespace and/or 369** SQL comments, then no SQL statements are evaluated and the database 370** is not changed. 371** 372** Restrictions: 373** 374** <ul> 375** <li> The application must insure that the 1st parameter to sqlite3_exec() 376** is a valid and open [database connection]. 377** <li> The application must not close the [database connection] specified by 378** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 379** <li> The application must not modify the SQL statement text passed into 380** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 381** </ul> 382*/ 383SQLITE_API int SQLITE_STDCALL sqlite3_exec( 384 sqlite3*, /* An open database */ 385 const char *sql, /* SQL to be evaluated */ 386 int (*callback)(void*,int,char**,char**), /* Callback function */ 387 void *, /* 1st argument to callback */ 388 char **errmsg /* Error msg written here */ 389); 390 391/* 392** CAPI3REF: Result Codes 393** KEYWORDS: {result code definitions} 394** 395** Many SQLite functions return an integer result code from the set shown 396** here in order to indicate success or failure. 397** 398** New error codes may be added in future versions of SQLite. 399** 400** See also: [extended result code definitions] 401*/ 402#define SQLITE_OK 0 /* Successful result */ 403/* beginning-of-error-codes */ 404#define SQLITE_ERROR 1 /* SQL error or missing database */ 405#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 406#define SQLITE_PERM 3 /* Access permission denied */ 407#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 408#define SQLITE_BUSY 5 /* The database file is locked */ 409#define SQLITE_LOCKED 6 /* A table in the database is locked */ 410#define SQLITE_NOMEM 7 /* A malloc() failed */ 411#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 412#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 413#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 414#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 415#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 416#define SQLITE_FULL 13 /* Insertion failed because database is full */ 417#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 418#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 419#define SQLITE_EMPTY 16 /* Database is empty */ 420#define SQLITE_SCHEMA 17 /* The database schema changed */ 421#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 422#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 423#define SQLITE_MISMATCH 20 /* Data type mismatch */ 424#define SQLITE_MISUSE 21 /* Library used incorrectly */ 425#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 426#define SQLITE_AUTH 23 /* Authorization denied */ 427#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 428#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 429#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 430#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 431#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 432#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 433#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 434/* end-of-error-codes */ 435 436/* 437** CAPI3REF: Extended Result Codes 438** KEYWORDS: {extended result code definitions} 439** 440** In its default configuration, SQLite API routines return one of 30 integer 441** [result codes]. However, experience has shown that many of 442** these result codes are too coarse-grained. They do not provide as 443** much information about problems as programmers might like. In an effort to 444** address this, newer versions of SQLite (version 3.3.8 and later) include 445** support for additional result codes that provide more detailed information 446** about errors. These [extended result codes] are enabled or disabled 447** on a per database connection basis using the 448** [sqlite3_extended_result_codes()] API. Or, the extended code for 449** the most recent error can be obtained using 450** [sqlite3_extended_errcode()]. 451*/ 452#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 453#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 454#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 455#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 456#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 457#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 458#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 459#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 460#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 461#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 462#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 463#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 464#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 465#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 466#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 467#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 468#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 469#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 470#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 471#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 472#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 473#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 474#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 475#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 476#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 477#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 478#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 479#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 480#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 481#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 482#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 483#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 484#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 485#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 486#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 487#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 488#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 489#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 490#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 491#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 492#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 493#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 494#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 495#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 496#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 497#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 498#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 499#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 500#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 501#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 502#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 503#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 504#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 505 506/* 507** CAPI3REF: Flags For File Open Operations 508** 509** These bit values are intended for use in the 510** 3rd parameter to the [sqlite3_open_v2()] interface and 511** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 512*/ 513#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 514#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 515#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 516#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 517#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 518#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 519#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 520#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 521#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 522#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 523#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 524#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 525#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 526#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 527#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 528#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 529#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 530#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 531#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 532#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 533 534/* Reserved: 0x00F00000 */ 535 536/* 537** CAPI3REF: Device Characteristics 538** 539** The xDeviceCharacteristics method of the [sqlite3_io_methods] 540** object returns an integer which is a vector of these 541** bit values expressing I/O characteristics of the mass storage 542** device that holds the file that the [sqlite3_io_methods] 543** refers to. 544** 545** The SQLITE_IOCAP_ATOMIC property means that all writes of 546** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 547** mean that writes of blocks that are nnn bytes in size and 548** are aligned to an address which is an integer multiple of 549** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 550** that when data is appended to a file, the data is appended 551** first then the size of the file is extended, never the other 552** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 553** information is written to disk in the same order as calls 554** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 555** after reboot following a crash or power loss, the only bytes in a 556** file that were written at the application level might have changed 557** and that adjacent bytes, even bytes within the same sector are 558** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 559** flag indicate that a file cannot be deleted when open. The 560** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 561** read-only media and cannot be changed even by processes with 562** elevated privileges. 563*/ 564#define SQLITE_IOCAP_ATOMIC 0x00000001 565#define SQLITE_IOCAP_ATOMIC512 0x00000002 566#define SQLITE_IOCAP_ATOMIC1K 0x00000004 567#define SQLITE_IOCAP_ATOMIC2K 0x00000008 568#define SQLITE_IOCAP_ATOMIC4K 0x00000010 569#define SQLITE_IOCAP_ATOMIC8K 0x00000020 570#define SQLITE_IOCAP_ATOMIC16K 0x00000040 571#define SQLITE_IOCAP_ATOMIC32K 0x00000080 572#define SQLITE_IOCAP_ATOMIC64K 0x00000100 573#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 574#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 575#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 576#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 577#define SQLITE_IOCAP_IMMUTABLE 0x00002000 578 579/* 580** CAPI3REF: File Locking Levels 581** 582** SQLite uses one of these integer values as the second 583** argument to calls it makes to the xLock() and xUnlock() methods 584** of an [sqlite3_io_methods] object. 585*/ 586#define SQLITE_LOCK_NONE 0 587#define SQLITE_LOCK_SHARED 1 588#define SQLITE_LOCK_RESERVED 2 589#define SQLITE_LOCK_PENDING 3 590#define SQLITE_LOCK_EXCLUSIVE 4 591 592/* 593** CAPI3REF: Synchronization Type Flags 594** 595** When SQLite invokes the xSync() method of an 596** [sqlite3_io_methods] object it uses a combination of 597** these integer values as the second argument. 598** 599** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 600** sync operation only needs to flush data to mass storage. Inode 601** information need not be flushed. If the lower four bits of the flag 602** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 603** If the lower four bits equal SQLITE_SYNC_FULL, that means 604** to use Mac OS X style fullsync instead of fsync(). 605** 606** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 607** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 608** settings. The [synchronous pragma] determines when calls to the 609** xSync VFS method occur and applies uniformly across all platforms. 610** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 611** energetic or rigorous or forceful the sync operations are and 612** only make a difference on Mac OSX for the default SQLite code. 613** (Third-party VFS implementations might also make the distinction 614** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 615** operating systems natively supported by SQLite, only Mac OSX 616** cares about the difference.) 617*/ 618#define SQLITE_SYNC_NORMAL 0x00002 619#define SQLITE_SYNC_FULL 0x00003 620#define SQLITE_SYNC_DATAONLY 0x00010 621 622/* 623** CAPI3REF: OS Interface Open File Handle 624** 625** An [sqlite3_file] object represents an open file in the 626** [sqlite3_vfs | OS interface layer]. Individual OS interface 627** implementations will 628** want to subclass this object by appending additional fields 629** for their own use. The pMethods entry is a pointer to an 630** [sqlite3_io_methods] object that defines methods for performing 631** I/O operations on the open file. 632*/ 633typedef struct sqlite3_file sqlite3_file; 634struct sqlite3_file { 635 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 636}; 637 638/* 639** CAPI3REF: OS Interface File Virtual Methods Object 640** 641** Every file opened by the [sqlite3_vfs.xOpen] method populates an 642** [sqlite3_file] object (or, more commonly, a subclass of the 643** [sqlite3_file] object) with a pointer to an instance of this object. 644** This object defines the methods used to perform various operations 645** against the open file represented by the [sqlite3_file] object. 646** 647** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 648** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 649** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 650** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 651** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 652** to NULL. 653** 654** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 655** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 656** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 657** flag may be ORed in to indicate that only the data of the file 658** and not its inode needs to be synced. 659** 660** The integer values to xLock() and xUnlock() are one of 661** <ul> 662** <li> [SQLITE_LOCK_NONE], 663** <li> [SQLITE_LOCK_SHARED], 664** <li> [SQLITE_LOCK_RESERVED], 665** <li> [SQLITE_LOCK_PENDING], or 666** <li> [SQLITE_LOCK_EXCLUSIVE]. 667** </ul> 668** xLock() increases the lock. xUnlock() decreases the lock. 669** The xCheckReservedLock() method checks whether any database connection, 670** either in this process or in some other process, is holding a RESERVED, 671** PENDING, or EXCLUSIVE lock on the file. It returns true 672** if such a lock exists and false otherwise. 673** 674** The xFileControl() method is a generic interface that allows custom 675** VFS implementations to directly control an open file using the 676** [sqlite3_file_control()] interface. The second "op" argument is an 677** integer opcode. The third argument is a generic pointer intended to 678** point to a structure that may contain arguments or space in which to 679** write return values. Potential uses for xFileControl() might be 680** functions to enable blocking locks with timeouts, to change the 681** locking strategy (for example to use dot-file locks), to inquire 682** about the status of a lock, or to break stale locks. The SQLite 683** core reserves all opcodes less than 100 for its own use. 684** A [file control opcodes | list of opcodes] less than 100 is available. 685** Applications that define a custom xFileControl method should use opcodes 686** greater than 100 to avoid conflicts. VFS implementations should 687** return [SQLITE_NOTFOUND] for file control opcodes that they do not 688** recognize. 689** 690** The xSectorSize() method returns the sector size of the 691** device that underlies the file. The sector size is the 692** minimum write that can be performed without disturbing 693** other bytes in the file. The xDeviceCharacteristics() 694** method returns a bit vector describing behaviors of the 695** underlying device: 696** 697** <ul> 698** <li> [SQLITE_IOCAP_ATOMIC] 699** <li> [SQLITE_IOCAP_ATOMIC512] 700** <li> [SQLITE_IOCAP_ATOMIC1K] 701** <li> [SQLITE_IOCAP_ATOMIC2K] 702** <li> [SQLITE_IOCAP_ATOMIC4K] 703** <li> [SQLITE_IOCAP_ATOMIC8K] 704** <li> [SQLITE_IOCAP_ATOMIC16K] 705** <li> [SQLITE_IOCAP_ATOMIC32K] 706** <li> [SQLITE_IOCAP_ATOMIC64K] 707** <li> [SQLITE_IOCAP_SAFE_APPEND] 708** <li> [SQLITE_IOCAP_SEQUENTIAL] 709** </ul> 710** 711** The SQLITE_IOCAP_ATOMIC property means that all writes of 712** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 713** mean that writes of blocks that are nnn bytes in size and 714** are aligned to an address which is an integer multiple of 715** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 716** that when data is appended to a file, the data is appended 717** first then the size of the file is extended, never the other 718** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 719** information is written to disk in the same order as calls 720** to xWrite(). 721** 722** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 723** in the unread portions of the buffer with zeros. A VFS that 724** fails to zero-fill short reads might seem to work. However, 725** failure to zero-fill short reads will eventually lead to 726** database corruption. 727*/ 728typedef struct sqlite3_io_methods sqlite3_io_methods; 729struct sqlite3_io_methods { 730 int iVersion; 731 int (*xClose)(sqlite3_file*); 732 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 733 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 734 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 735 int (*xSync)(sqlite3_file*, int flags); 736 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 737 int (*xLock)(sqlite3_file*, int); 738 int (*xUnlock)(sqlite3_file*, int); 739 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 740 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 741 int (*xSectorSize)(sqlite3_file*); 742 int (*xDeviceCharacteristics)(sqlite3_file*); 743 /* Methods above are valid for version 1 */ 744 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 745 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 746 void (*xShmBarrier)(sqlite3_file*); 747 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 748 /* Methods above are valid for version 2 */ 749 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 750 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 751 /* Methods above are valid for version 3 */ 752 /* Additional methods may be added in future releases */ 753}; 754 755/* 756** CAPI3REF: Standard File Control Opcodes 757** KEYWORDS: {file control opcodes} {file control opcode} 758** 759** These integer constants are opcodes for the xFileControl method 760** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 761** interface. 762** 763** <ul> 764** <li>[[SQLITE_FCNTL_LOCKSTATE]] 765** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 766** opcode causes the xFileControl method to write the current state of 767** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 768** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 769** into an integer that the pArg argument points to. This capability 770** is used during testing and is only available when the SQLITE_TEST 771** compile-time option is used. 772** 773** <li>[[SQLITE_FCNTL_SIZE_HINT]] 774** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 775** layer a hint of how large the database file will grow to be during the 776** current transaction. This hint is not guaranteed to be accurate but it 777** is often close. The underlying VFS might choose to preallocate database 778** file space based on this hint in order to help writes to the database 779** file run faster. 780** 781** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 782** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 783** extends and truncates the database file in chunks of a size specified 784** by the user. The fourth argument to [sqlite3_file_control()] should 785** point to an integer (type int) containing the new chunk-size to use 786** for the nominated database. Allocating database file space in large 787** chunks (say 1MB at a time), may reduce file-system fragmentation and 788** improve performance on some systems. 789** 790** <li>[[SQLITE_FCNTL_FILE_POINTER]] 791** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 792** to the [sqlite3_file] object associated with a particular database 793** connection. See the [sqlite3_file_control()] documentation for 794** additional information. 795** 796** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 797** No longer in use. 798** 799** <li>[[SQLITE_FCNTL_SYNC]] 800** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 801** sent to the VFS immediately before the xSync method is invoked on a 802** database file descriptor. Or, if the xSync method is not invoked 803** because the user has configured SQLite with 804** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 805** of the xSync method. In most cases, the pointer argument passed with 806** this file-control is NULL. However, if the database file is being synced 807** as part of a multi-database commit, the argument points to a nul-terminated 808** string containing the transactions master-journal file name. VFSes that 809** do not need this signal should silently ignore this opcode. Applications 810** should not call [sqlite3_file_control()] with this opcode as doing so may 811** disrupt the operation of the specialized VFSes that do require it. 812** 813** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 814** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 815** and sent to the VFS after a transaction has been committed immediately 816** but before the database is unlocked. VFSes that do not need this signal 817** should silently ignore this opcode. Applications should not call 818** [sqlite3_file_control()] with this opcode as doing so may disrupt the 819** operation of the specialized VFSes that do require it. 820** 821** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 822** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 823** retry counts and intervals for certain disk I/O operations for the 824** windows [VFS] in order to provide robustness in the presence of 825** anti-virus programs. By default, the windows VFS will retry file read, 826** file write, and file delete operations up to 10 times, with a delay 827** of 25 milliseconds before the first retry and with the delay increasing 828** by an additional 25 milliseconds with each subsequent retry. This 829** opcode allows these two values (10 retries and 25 milliseconds of delay) 830** to be adjusted. The values are changed for all database connections 831** within the same process. The argument is a pointer to an array of two 832** integers where the first integer i the new retry count and the second 833** integer is the delay. If either integer is negative, then the setting 834** is not changed but instead the prior value of that setting is written 835** into the array entry, allowing the current retry settings to be 836** interrogated. The zDbName parameter is ignored. 837** 838** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 839** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 840** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 841** write ahead log and shared memory files used for transaction control 842** are automatically deleted when the latest connection to the database 843** closes. Setting persistent WAL mode causes those files to persist after 844** close. Persisting the files is useful when other processes that do not 845** have write permission on the directory containing the database file want 846** to read the database file, as the WAL and shared memory files must exist 847** in order for the database to be readable. The fourth parameter to 848** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 849** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 850** WAL mode. If the integer is -1, then it is overwritten with the current 851** WAL persistence setting. 852** 853** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 854** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 855** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 856** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 857** xDeviceCharacteristics methods. The fourth parameter to 858** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 859** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 860** mode. If the integer is -1, then it is overwritten with the current 861** zero-damage mode setting. 862** 863** <li>[[SQLITE_FCNTL_OVERWRITE]] 864** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 865** a write transaction to indicate that, unless it is rolled back for some 866** reason, the entire database file will be overwritten by the current 867** transaction. This is used by VACUUM operations. 868** 869** <li>[[SQLITE_FCNTL_VFSNAME]] 870** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 871** all [VFSes] in the VFS stack. The names are of all VFS shims and the 872** final bottom-level VFS are written into memory obtained from 873** [sqlite3_malloc()] and the result is stored in the char* variable 874** that the fourth parameter of [sqlite3_file_control()] points to. 875** The caller is responsible for freeing the memory when done. As with 876** all file-control actions, there is no guarantee that this will actually 877** do anything. Callers should initialize the char* variable to a NULL 878** pointer in case this file-control is not implemented. This file-control 879** is intended for diagnostic use only. 880** 881** <li>[[SQLITE_FCNTL_PRAGMA]] 882** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 883** file control is sent to the open [sqlite3_file] object corresponding 884** to the database file to which the pragma statement refers. ^The argument 885** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 886** pointers to strings (char**) in which the second element of the array 887** is the name of the pragma and the third element is the argument to the 888** pragma or NULL if the pragma has no argument. ^The handler for an 889** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 890** of the char** argument point to a string obtained from [sqlite3_mprintf()] 891** or the equivalent and that string will become the result of the pragma or 892** the error message if the pragma fails. ^If the 893** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 894** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 895** file control returns [SQLITE_OK], then the parser assumes that the 896** VFS has handled the PRAGMA itself and the parser generates a no-op 897** prepared statement if result string is NULL, or that returns a copy 898** of the result string if the string is non-NULL. 899** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 900** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 901** that the VFS encountered an error while handling the [PRAGMA] and the 902** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 903** file control occurs at the beginning of pragma statement analysis and so 904** it is able to override built-in [PRAGMA] statements. 905** 906** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 907** ^The [SQLITE_FCNTL_BUSYHANDLER] 908** file-control may be invoked by SQLite on the database file handle 909** shortly after it is opened in order to provide a custom VFS with access 910** to the connections busy-handler callback. The argument is of type (void **) 911** - an array of two (void *) values. The first (void *) actually points 912** to a function of type (int (*)(void *)). In order to invoke the connections 913** busy-handler, this function should be invoked with the second (void *) in 914** the array as the only argument. If it returns non-zero, then the operation 915** should be retried. If it returns zero, the custom VFS should abandon the 916** current operation. 917** 918** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 919** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 920** to have SQLite generate a 921** temporary filename using the same algorithm that is followed to generate 922** temporary filenames for TEMP tables and other internal uses. The 923** argument should be a char** which will be filled with the filename 924** written into memory obtained from [sqlite3_malloc()]. The caller should 925** invoke [sqlite3_free()] on the result to avoid a memory leak. 926** 927** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 928** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 929** maximum number of bytes that will be used for memory-mapped I/O. 930** The argument is a pointer to a value of type sqlite3_int64 that 931** is an advisory maximum number of bytes in the file to memory map. The 932** pointer is overwritten with the old value. The limit is not changed if 933** the value originally pointed to is negative, and so the current limit 934** can be queried by passing in a pointer to a negative number. This 935** file-control is used internally to implement [PRAGMA mmap_size]. 936** 937** <li>[[SQLITE_FCNTL_TRACE]] 938** The [SQLITE_FCNTL_TRACE] file control provides advisory information 939** to the VFS about what the higher layers of the SQLite stack are doing. 940** This file control is used by some VFS activity tracing [shims]. 941** The argument is a zero-terminated string. Higher layers in the 942** SQLite stack may generate instances of this file control if 943** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 944** 945** <li>[[SQLITE_FCNTL_HAS_MOVED]] 946** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 947** pointer to an integer and it writes a boolean into that integer depending 948** on whether or not the file has been renamed, moved, or deleted since it 949** was first opened. 950** 951** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 952** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 953** opcode causes the xFileControl method to swap the file handle with the one 954** pointed to by the pArg argument. This capability is used during testing 955** and only needs to be supported when SQLITE_TEST is defined. 956** 957** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 958** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 959** be advantageous to block on the next WAL lock if the lock is not immediately 960** available. The WAL subsystem issues this signal during rare 961** circumstances in order to fix a problem with priority inversion. 962** Applications should <em>not</em> use this file-control. 963** 964** </ul> 965*/ 966#define SQLITE_FCNTL_LOCKSTATE 1 967#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 968#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 969#define SQLITE_FCNTL_LAST_ERRNO 4 970#define SQLITE_FCNTL_SIZE_HINT 5 971#define SQLITE_FCNTL_CHUNK_SIZE 6 972#define SQLITE_FCNTL_FILE_POINTER 7 973#define SQLITE_FCNTL_SYNC_OMITTED 8 974#define SQLITE_FCNTL_WIN32_AV_RETRY 9 975#define SQLITE_FCNTL_PERSIST_WAL 10 976#define SQLITE_FCNTL_OVERWRITE 11 977#define SQLITE_FCNTL_VFSNAME 12 978#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 979#define SQLITE_FCNTL_PRAGMA 14 980#define SQLITE_FCNTL_BUSYHANDLER 15 981#define SQLITE_FCNTL_TEMPFILENAME 16 982#define SQLITE_FCNTL_MMAP_SIZE 18 983#define SQLITE_FCNTL_TRACE 19 984#define SQLITE_FCNTL_HAS_MOVED 20 985#define SQLITE_FCNTL_SYNC 21 986#define SQLITE_FCNTL_COMMIT_PHASETWO 22 987#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 988#define SQLITE_FCNTL_WAL_BLOCK 24 989 990/* deprecated names */ 991#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 992#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 993#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 994 995 996/* 997** CAPI3REF: Mutex Handle 998** 999** The mutex module within SQLite defines [sqlite3_mutex] to be an 1000** abstract type for a mutex object. The SQLite core never looks 1001** at the internal representation of an [sqlite3_mutex]. It only 1002** deals with pointers to the [sqlite3_mutex] object. 1003** 1004** Mutexes are created using [sqlite3_mutex_alloc()]. 1005*/ 1006typedef struct sqlite3_mutex sqlite3_mutex; 1007 1008/* 1009** CAPI3REF: OS Interface Object 1010** 1011** An instance of the sqlite3_vfs object defines the interface between 1012** the SQLite core and the underlying operating system. The "vfs" 1013** in the name of the object stands for "virtual file system". See 1014** the [VFS | VFS documentation] for further information. 1015** 1016** The value of the iVersion field is initially 1 but may be larger in 1017** future versions of SQLite. Additional fields may be appended to this 1018** object when the iVersion value is increased. Note that the structure 1019** of the sqlite3_vfs object changes in the transaction between 1020** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1021** modified. 1022** 1023** The szOsFile field is the size of the subclassed [sqlite3_file] 1024** structure used by this VFS. mxPathname is the maximum length of 1025** a pathname in this VFS. 1026** 1027** Registered sqlite3_vfs objects are kept on a linked list formed by 1028** the pNext pointer. The [sqlite3_vfs_register()] 1029** and [sqlite3_vfs_unregister()] interfaces manage this list 1030** in a thread-safe way. The [sqlite3_vfs_find()] interface 1031** searches the list. Neither the application code nor the VFS 1032** implementation should use the pNext pointer. 1033** 1034** The pNext field is the only field in the sqlite3_vfs 1035** structure that SQLite will ever modify. SQLite will only access 1036** or modify this field while holding a particular static mutex. 1037** The application should never modify anything within the sqlite3_vfs 1038** object once the object has been registered. 1039** 1040** The zName field holds the name of the VFS module. The name must 1041** be unique across all VFS modules. 1042** 1043** [[sqlite3_vfs.xOpen]] 1044** ^SQLite guarantees that the zFilename parameter to xOpen 1045** is either a NULL pointer or string obtained 1046** from xFullPathname() with an optional suffix added. 1047** ^If a suffix is added to the zFilename parameter, it will 1048** consist of a single "-" character followed by no more than 1049** 11 alphanumeric and/or "-" characters. 1050** ^SQLite further guarantees that 1051** the string will be valid and unchanged until xClose() is 1052** called. Because of the previous sentence, 1053** the [sqlite3_file] can safely store a pointer to the 1054** filename if it needs to remember the filename for some reason. 1055** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1056** must invent its own temporary name for the file. ^Whenever the 1057** xFilename parameter is NULL it will also be the case that the 1058** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1059** 1060** The flags argument to xOpen() includes all bits set in 1061** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1062** or [sqlite3_open16()] is used, then flags includes at least 1063** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1064** If xOpen() opens a file read-only then it sets *pOutFlags to 1065** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1066** 1067** ^(SQLite will also add one of the following flags to the xOpen() 1068** call, depending on the object being opened: 1069** 1070** <ul> 1071** <li> [SQLITE_OPEN_MAIN_DB] 1072** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1073** <li> [SQLITE_OPEN_TEMP_DB] 1074** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1075** <li> [SQLITE_OPEN_TRANSIENT_DB] 1076** <li> [SQLITE_OPEN_SUBJOURNAL] 1077** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1078** <li> [SQLITE_OPEN_WAL] 1079** </ul>)^ 1080** 1081** The file I/O implementation can use the object type flags to 1082** change the way it deals with files. For example, an application 1083** that does not care about crash recovery or rollback might make 1084** the open of a journal file a no-op. Writes to this journal would 1085** also be no-ops, and any attempt to read the journal would return 1086** SQLITE_IOERR. Or the implementation might recognize that a database 1087** file will be doing page-aligned sector reads and writes in a random 1088** order and set up its I/O subsystem accordingly. 1089** 1090** SQLite might also add one of the following flags to the xOpen method: 1091** 1092** <ul> 1093** <li> [SQLITE_OPEN_DELETEONCLOSE] 1094** <li> [SQLITE_OPEN_EXCLUSIVE] 1095** </ul> 1096** 1097** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1098** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1099** will be set for TEMP databases and their journals, transient 1100** databases, and subjournals. 1101** 1102** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1103** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1104** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1105** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1106** SQLITE_OPEN_CREATE, is used to indicate that file should always 1107** be created, and that it is an error if it already exists. 1108** It is <i>not</i> used to indicate the file should be opened 1109** for exclusive access. 1110** 1111** ^At least szOsFile bytes of memory are allocated by SQLite 1112** to hold the [sqlite3_file] structure passed as the third 1113** argument to xOpen. The xOpen method does not have to 1114** allocate the structure; it should just fill it in. Note that 1115** the xOpen method must set the sqlite3_file.pMethods to either 1116** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1117** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1118** element will be valid after xOpen returns regardless of the success 1119** or failure of the xOpen call. 1120** 1121** [[sqlite3_vfs.xAccess]] 1122** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1123** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1124** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1125** to test whether a file is at least readable. The file can be a 1126** directory. 1127** 1128** ^SQLite will always allocate at least mxPathname+1 bytes for the 1129** output buffer xFullPathname. The exact size of the output buffer 1130** is also passed as a parameter to both methods. If the output buffer 1131** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1132** handled as a fatal error by SQLite, vfs implementations should endeavor 1133** to prevent this by setting mxPathname to a sufficiently large value. 1134** 1135** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1136** interfaces are not strictly a part of the filesystem, but they are 1137** included in the VFS structure for completeness. 1138** The xRandomness() function attempts to return nBytes bytes 1139** of good-quality randomness into zOut. The return value is 1140** the actual number of bytes of randomness obtained. 1141** The xSleep() method causes the calling thread to sleep for at 1142** least the number of microseconds given. ^The xCurrentTime() 1143** method returns a Julian Day Number for the current date and time as 1144** a floating point value. 1145** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1146** Day Number multiplied by 86400000 (the number of milliseconds in 1147** a 24-hour day). 1148** ^SQLite will use the xCurrentTimeInt64() method to get the current 1149** date and time if that method is available (if iVersion is 2 or 1150** greater and the function pointer is not NULL) and will fall back 1151** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1152** 1153** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1154** are not used by the SQLite core. These optional interfaces are provided 1155** by some VFSes to facilitate testing of the VFS code. By overriding 1156** system calls with functions under its control, a test program can 1157** simulate faults and error conditions that would otherwise be difficult 1158** or impossible to induce. The set of system calls that can be overridden 1159** varies from one VFS to another, and from one version of the same VFS to the 1160** next. Applications that use these interfaces must be prepared for any 1161** or all of these interfaces to be NULL or for their behavior to change 1162** from one release to the next. Applications must not attempt to access 1163** any of these methods if the iVersion of the VFS is less than 3. 1164*/ 1165typedef struct sqlite3_vfs sqlite3_vfs; 1166typedef void (*sqlite3_syscall_ptr)(void); 1167struct sqlite3_vfs { 1168 int iVersion; /* Structure version number (currently 3) */ 1169 int szOsFile; /* Size of subclassed sqlite3_file */ 1170 int mxPathname; /* Maximum file pathname length */ 1171 sqlite3_vfs *pNext; /* Next registered VFS */ 1172 const char *zName; /* Name of this virtual file system */ 1173 void *pAppData; /* Pointer to application-specific data */ 1174 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1175 int flags, int *pOutFlags); 1176 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1177 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1178 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1179 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1180 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1181 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1182 void (*xDlClose)(sqlite3_vfs*, void*); 1183 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1184 int (*xSleep)(sqlite3_vfs*, int microseconds); 1185 int (*xCurrentTime)(sqlite3_vfs*, double*); 1186 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1187 /* 1188 ** The methods above are in version 1 of the sqlite_vfs object 1189 ** definition. Those that follow are added in version 2 or later 1190 */ 1191 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1192 /* 1193 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1194 ** Those below are for version 3 and greater. 1195 */ 1196 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1197 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1198 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1199 /* 1200 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1201 ** New fields may be appended in figure versions. The iVersion 1202 ** value will increment whenever this happens. 1203 */ 1204}; 1205 1206/* 1207** CAPI3REF: Flags for the xAccess VFS method 1208** 1209** These integer constants can be used as the third parameter to 1210** the xAccess method of an [sqlite3_vfs] object. They determine 1211** what kind of permissions the xAccess method is looking for. 1212** With SQLITE_ACCESS_EXISTS, the xAccess method 1213** simply checks whether the file exists. 1214** With SQLITE_ACCESS_READWRITE, the xAccess method 1215** checks whether the named directory is both readable and writable 1216** (in other words, if files can be added, removed, and renamed within 1217** the directory). 1218** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1219** [temp_store_directory pragma], though this could change in a future 1220** release of SQLite. 1221** With SQLITE_ACCESS_READ, the xAccess method 1222** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1223** currently unused, though it might be used in a future release of 1224** SQLite. 1225*/ 1226#define SQLITE_ACCESS_EXISTS 0 1227#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1228#define SQLITE_ACCESS_READ 2 /* Unused */ 1229 1230/* 1231** CAPI3REF: Flags for the xShmLock VFS method 1232** 1233** These integer constants define the various locking operations 1234** allowed by the xShmLock method of [sqlite3_io_methods]. The 1235** following are the only legal combinations of flags to the 1236** xShmLock method: 1237** 1238** <ul> 1239** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1240** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1241** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1242** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1243** </ul> 1244** 1245** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1246** was given on the corresponding lock. 1247** 1248** The xShmLock method can transition between unlocked and SHARED or 1249** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1250** and EXCLUSIVE. 1251*/ 1252#define SQLITE_SHM_UNLOCK 1 1253#define SQLITE_SHM_LOCK 2 1254#define SQLITE_SHM_SHARED 4 1255#define SQLITE_SHM_EXCLUSIVE 8 1256 1257/* 1258** CAPI3REF: Maximum xShmLock index 1259** 1260** The xShmLock method on [sqlite3_io_methods] may use values 1261** between 0 and this upper bound as its "offset" argument. 1262** The SQLite core will never attempt to acquire or release a 1263** lock outside of this range 1264*/ 1265#define SQLITE_SHM_NLOCK 8 1266 1267 1268/* 1269** CAPI3REF: Initialize The SQLite Library 1270** 1271** ^The sqlite3_initialize() routine initializes the 1272** SQLite library. ^The sqlite3_shutdown() routine 1273** deallocates any resources that were allocated by sqlite3_initialize(). 1274** These routines are designed to aid in process initialization and 1275** shutdown on embedded systems. Workstation applications using 1276** SQLite normally do not need to invoke either of these routines. 1277** 1278** A call to sqlite3_initialize() is an "effective" call if it is 1279** the first time sqlite3_initialize() is invoked during the lifetime of 1280** the process, or if it is the first time sqlite3_initialize() is invoked 1281** following a call to sqlite3_shutdown(). ^(Only an effective call 1282** of sqlite3_initialize() does any initialization. All other calls 1283** are harmless no-ops.)^ 1284** 1285** A call to sqlite3_shutdown() is an "effective" call if it is the first 1286** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1287** an effective call to sqlite3_shutdown() does any deinitialization. 1288** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1289** 1290** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1291** is not. The sqlite3_shutdown() interface must only be called from a 1292** single thread. All open [database connections] must be closed and all 1293** other SQLite resources must be deallocated prior to invoking 1294** sqlite3_shutdown(). 1295** 1296** Among other things, ^sqlite3_initialize() will invoke 1297** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1298** will invoke sqlite3_os_end(). 1299** 1300** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1301** ^If for some reason, sqlite3_initialize() is unable to initialize 1302** the library (perhaps it is unable to allocate a needed resource such 1303** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1304** 1305** ^The sqlite3_initialize() routine is called internally by many other 1306** SQLite interfaces so that an application usually does not need to 1307** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1308** calls sqlite3_initialize() so the SQLite library will be automatically 1309** initialized when [sqlite3_open()] is called if it has not be initialized 1310** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1311** compile-time option, then the automatic calls to sqlite3_initialize() 1312** are omitted and the application must call sqlite3_initialize() directly 1313** prior to using any other SQLite interface. For maximum portability, 1314** it is recommended that applications always invoke sqlite3_initialize() 1315** directly prior to using any other SQLite interface. Future releases 1316** of SQLite may require this. In other words, the behavior exhibited 1317** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1318** default behavior in some future release of SQLite. 1319** 1320** The sqlite3_os_init() routine does operating-system specific 1321** initialization of the SQLite library. The sqlite3_os_end() 1322** routine undoes the effect of sqlite3_os_init(). Typical tasks 1323** performed by these routines include allocation or deallocation 1324** of static resources, initialization of global variables, 1325** setting up a default [sqlite3_vfs] module, or setting up 1326** a default configuration using [sqlite3_config()]. 1327** 1328** The application should never invoke either sqlite3_os_init() 1329** or sqlite3_os_end() directly. The application should only invoke 1330** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1331** interface is called automatically by sqlite3_initialize() and 1332** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1333** implementations for sqlite3_os_init() and sqlite3_os_end() 1334** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1335** When [custom builds | built for other platforms] 1336** (using the [SQLITE_OS_OTHER=1] compile-time 1337** option) the application must supply a suitable implementation for 1338** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1339** implementation of sqlite3_os_init() or sqlite3_os_end() 1340** must return [SQLITE_OK] on success and some other [error code] upon 1341** failure. 1342*/ 1343SQLITE_API int SQLITE_STDCALL sqlite3_initialize(void); 1344SQLITE_API int SQLITE_STDCALL sqlite3_shutdown(void); 1345SQLITE_API int SQLITE_STDCALL sqlite3_os_init(void); 1346SQLITE_API int SQLITE_STDCALL sqlite3_os_end(void); 1347 1348/* 1349** CAPI3REF: Configuring The SQLite Library 1350** 1351** The sqlite3_config() interface is used to make global configuration 1352** changes to SQLite in order to tune SQLite to the specific needs of 1353** the application. The default configuration is recommended for most 1354** applications and so this routine is usually not necessary. It is 1355** provided to support rare applications with unusual needs. 1356** 1357** The sqlite3_config() interface is not threadsafe. The application 1358** must insure that no other SQLite interfaces are invoked by other 1359** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1360** may only be invoked prior to library initialization using 1361** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1362** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1363** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1364** Note, however, that ^sqlite3_config() can be called as part of the 1365** implementation of an application-defined [sqlite3_os_init()]. 1366** 1367** The first argument to sqlite3_config() is an integer 1368** [configuration option] that determines 1369** what property of SQLite is to be configured. Subsequent arguments 1370** vary depending on the [configuration option] 1371** in the first argument. 1372** 1373** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1374** ^If the option is unknown or SQLite is unable to set the option 1375** then this routine returns a non-zero [error code]. 1376*/ 1377SQLITE_API int SQLITE_CDECL sqlite3_config(int, ...); 1378 1379/* 1380** CAPI3REF: Configure database connections 1381** 1382** The sqlite3_db_config() interface is used to make configuration 1383** changes to a [database connection]. The interface is similar to 1384** [sqlite3_config()] except that the changes apply to a single 1385** [database connection] (specified in the first argument). 1386** 1387** The second argument to sqlite3_db_config(D,V,...) is the 1388** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1389** that indicates what aspect of the [database connection] is being configured. 1390** Subsequent arguments vary depending on the configuration verb. 1391** 1392** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1393** the call is considered successful. 1394*/ 1395SQLITE_API int SQLITE_CDECL sqlite3_db_config(sqlite3*, int op, ...); 1396 1397/* 1398** CAPI3REF: Memory Allocation Routines 1399** 1400** An instance of this object defines the interface between SQLite 1401** and low-level memory allocation routines. 1402** 1403** This object is used in only one place in the SQLite interface. 1404** A pointer to an instance of this object is the argument to 1405** [sqlite3_config()] when the configuration option is 1406** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1407** By creating an instance of this object 1408** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1409** during configuration, an application can specify an alternative 1410** memory allocation subsystem for SQLite to use for all of its 1411** dynamic memory needs. 1412** 1413** Note that SQLite comes with several [built-in memory allocators] 1414** that are perfectly adequate for the overwhelming majority of applications 1415** and that this object is only useful to a tiny minority of applications 1416** with specialized memory allocation requirements. This object is 1417** also used during testing of SQLite in order to specify an alternative 1418** memory allocator that simulates memory out-of-memory conditions in 1419** order to verify that SQLite recovers gracefully from such 1420** conditions. 1421** 1422** The xMalloc, xRealloc, and xFree methods must work like the 1423** malloc(), realloc() and free() functions from the standard C library. 1424** ^SQLite guarantees that the second argument to 1425** xRealloc is always a value returned by a prior call to xRoundup. 1426** 1427** xSize should return the allocated size of a memory allocation 1428** previously obtained from xMalloc or xRealloc. The allocated size 1429** is always at least as big as the requested size but may be larger. 1430** 1431** The xRoundup method returns what would be the allocated size of 1432** a memory allocation given a particular requested size. Most memory 1433** allocators round up memory allocations at least to the next multiple 1434** of 8. Some allocators round up to a larger multiple or to a power of 2. 1435** Every memory allocation request coming in through [sqlite3_malloc()] 1436** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1437** that causes the corresponding memory allocation to fail. 1438** 1439** The xInit method initializes the memory allocator. For example, 1440** it might allocate any require mutexes or initialize internal data 1441** structures. The xShutdown method is invoked (indirectly) by 1442** [sqlite3_shutdown()] and should deallocate any resources acquired 1443** by xInit. The pAppData pointer is used as the only parameter to 1444** xInit and xShutdown. 1445** 1446** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1447** the xInit method, so the xInit method need not be threadsafe. The 1448** xShutdown method is only called from [sqlite3_shutdown()] so it does 1449** not need to be threadsafe either. For all other methods, SQLite 1450** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1451** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1452** it is by default) and so the methods are automatically serialized. 1453** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1454** methods must be threadsafe or else make their own arrangements for 1455** serialization. 1456** 1457** SQLite will never invoke xInit() more than once without an intervening 1458** call to xShutdown(). 1459*/ 1460typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1461struct sqlite3_mem_methods { 1462 void *(*xMalloc)(int); /* Memory allocation function */ 1463 void (*xFree)(void*); /* Free a prior allocation */ 1464 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1465 int (*xSize)(void*); /* Return the size of an allocation */ 1466 int (*xRoundup)(int); /* Round up request size to allocation size */ 1467 int (*xInit)(void*); /* Initialize the memory allocator */ 1468 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1469 void *pAppData; /* Argument to xInit() and xShutdown() */ 1470}; 1471 1472/* 1473** CAPI3REF: Configuration Options 1474** KEYWORDS: {configuration option} 1475** 1476** These constants are the available integer configuration options that 1477** can be passed as the first argument to the [sqlite3_config()] interface. 1478** 1479** New configuration options may be added in future releases of SQLite. 1480** Existing configuration options might be discontinued. Applications 1481** should check the return code from [sqlite3_config()] to make sure that 1482** the call worked. The [sqlite3_config()] interface will return a 1483** non-zero [error code] if a discontinued or unsupported configuration option 1484** is invoked. 1485** 1486** <dl> 1487** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1488** <dd>There are no arguments to this option. ^This option sets the 1489** [threading mode] to Single-thread. In other words, it disables 1490** all mutexing and puts SQLite into a mode where it can only be used 1491** by a single thread. ^If SQLite is compiled with 1492** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1493** it is not possible to change the [threading mode] from its default 1494** value of Single-thread and so [sqlite3_config()] will return 1495** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1496** configuration option.</dd> 1497** 1498** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1499** <dd>There are no arguments to this option. ^This option sets the 1500** [threading mode] to Multi-thread. In other words, it disables 1501** mutexing on [database connection] and [prepared statement] objects. 1502** The application is responsible for serializing access to 1503** [database connections] and [prepared statements]. But other mutexes 1504** are enabled so that SQLite will be safe to use in a multi-threaded 1505** environment as long as no two threads attempt to use the same 1506** [database connection] at the same time. ^If SQLite is compiled with 1507** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1508** it is not possible to set the Multi-thread [threading mode] and 1509** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1510** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1511** 1512** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1513** <dd>There are no arguments to this option. ^This option sets the 1514** [threading mode] to Serialized. In other words, this option enables 1515** all mutexes including the recursive 1516** mutexes on [database connection] and [prepared statement] objects. 1517** In this mode (which is the default when SQLite is compiled with 1518** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1519** to [database connections] and [prepared statements] so that the 1520** application is free to use the same [database connection] or the 1521** same [prepared statement] in different threads at the same time. 1522** ^If SQLite is compiled with 1523** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1524** it is not possible to set the Serialized [threading mode] and 1525** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1526** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1527** 1528** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1529** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1530** a pointer to an instance of the [sqlite3_mem_methods] structure. 1531** The argument specifies 1532** alternative low-level memory allocation routines to be used in place of 1533** the memory allocation routines built into SQLite.)^ ^SQLite makes 1534** its own private copy of the content of the [sqlite3_mem_methods] structure 1535** before the [sqlite3_config()] call returns.</dd> 1536** 1537** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1538** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1539** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1540** The [sqlite3_mem_methods] 1541** structure is filled with the currently defined memory allocation routines.)^ 1542** This option can be used to overload the default memory allocation 1543** routines with a wrapper that simulations memory allocation failure or 1544** tracks memory usage, for example. </dd> 1545** 1546** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1547** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1548** interpreted as a boolean, which enables or disables the collection of 1549** memory allocation statistics. ^(When memory allocation statistics are 1550** disabled, the following SQLite interfaces become non-operational: 1551** <ul> 1552** <li> [sqlite3_memory_used()] 1553** <li> [sqlite3_memory_highwater()] 1554** <li> [sqlite3_soft_heap_limit64()] 1555** <li> [sqlite3_status64()] 1556** </ul>)^ 1557** ^Memory allocation statistics are enabled by default unless SQLite is 1558** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1559** allocation statistics are disabled by default. 1560** </dd> 1561** 1562** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1563** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer 1564** that SQLite can use for scratch memory. ^(There are three arguments 1565** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte 1566** aligned memory buffer from which the scratch allocations will be 1567** drawn, the size of each scratch allocation (sz), 1568** and the maximum number of scratch allocations (N).)^ 1569** The first argument must be a pointer to an 8-byte aligned buffer 1570** of at least sz*N bytes of memory. 1571** ^SQLite will not use more than one scratch buffers per thread. 1572** ^SQLite will never request a scratch buffer that is more than 6 1573** times the database page size. 1574** ^If SQLite needs needs additional 1575** scratch memory beyond what is provided by this configuration option, then 1576** [sqlite3_malloc()] will be used to obtain the memory needed.<p> 1577** ^When the application provides any amount of scratch memory using 1578** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large 1579** [sqlite3_malloc|heap allocations]. 1580** This can help [Robson proof|prevent memory allocation failures] due to heap 1581** fragmentation in low-memory embedded systems. 1582** </dd> 1583** 1584** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1585** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer 1586** that SQLite can use for the database page cache with the default page 1587** cache implementation. 1588** This configuration should not be used if an application-define page 1589** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2] 1590** configuration option. 1591** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1592** 8-byte aligned 1593** memory, the size of each page buffer (sz), and the number of pages (N). 1594** The sz argument should be the size of the largest database page 1595** (a power of two between 512 and 65536) plus some extra bytes for each 1596** page header. ^The number of extra bytes needed by the page header 1597** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option 1598** to [sqlite3_config()]. 1599** ^It is harmless, apart from the wasted memory, 1600** for the sz parameter to be larger than necessary. The first 1601** argument should pointer to an 8-byte aligned block of memory that 1602** is at least sz*N bytes of memory, otherwise subsequent behavior is 1603** undefined. 1604** ^SQLite will use the memory provided by the first argument to satisfy its 1605** memory needs for the first N pages that it adds to cache. ^If additional 1606** page cache memory is needed beyond what is provided by this option, then 1607** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd> 1608** 1609** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1610** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1611** that SQLite will use for all of its dynamic memory allocation needs 1612** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and 1613** [SQLITE_CONFIG_PAGECACHE]. 1614** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1615** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1616** [SQLITE_ERROR] if invoked otherwise. 1617** ^There are three arguments to SQLITE_CONFIG_HEAP: 1618** An 8-byte aligned pointer to the memory, 1619** the number of bytes in the memory buffer, and the minimum allocation size. 1620** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1621** to using its default memory allocator (the system malloc() implementation), 1622** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1623** memory pointer is not NULL then the alternative memory 1624** allocator is engaged to handle all of SQLites memory allocation needs. 1625** The first pointer (the memory pointer) must be aligned to an 8-byte 1626** boundary or subsequent behavior of SQLite will be undefined. 1627** The minimum allocation size is capped at 2**12. Reasonable values 1628** for the minimum allocation size are 2**5 through 2**8.</dd> 1629** 1630** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1631** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1632** pointer to an instance of the [sqlite3_mutex_methods] structure. 1633** The argument specifies alternative low-level mutex routines to be used 1634** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1635** the content of the [sqlite3_mutex_methods] structure before the call to 1636** [sqlite3_config()] returns. ^If SQLite is compiled with 1637** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1638** the entire mutexing subsystem is omitted from the build and hence calls to 1639** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1640** return [SQLITE_ERROR].</dd> 1641** 1642** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1643** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1644** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1645** [sqlite3_mutex_methods] 1646** structure is filled with the currently defined mutex routines.)^ 1647** This option can be used to overload the default mutex allocation 1648** routines with a wrapper used to track mutex usage for performance 1649** profiling or testing, for example. ^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_GETMUTEX configuration option will 1653** return [SQLITE_ERROR].</dd> 1654** 1655** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1656** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1657** the default size of lookaside memory on each [database connection]. 1658** The first argument is the 1659** size of each lookaside buffer slot and the second is the number of 1660** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1661** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1662** option to [sqlite3_db_config()] can be used to change the lookaside 1663** configuration on individual connections.)^ </dd> 1664** 1665** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1666** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1667** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1668** the interface to a custom page cache implementation.)^ 1669** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1670** 1671** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1672** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1673** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1674** the current page cache implementation into that object.)^ </dd> 1675** 1676** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1677** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1678** global [error log]. 1679** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1680** function with a call signature of void(*)(void*,int,const char*), 1681** and a pointer to void. ^If the function pointer is not NULL, it is 1682** invoked by [sqlite3_log()] to process each logging event. ^If the 1683** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1684** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1685** passed through as the first parameter to the application-defined logger 1686** function whenever that function is invoked. ^The second parameter to 1687** the logger function is a copy of the first parameter to the corresponding 1688** [sqlite3_log()] call and is intended to be a [result code] or an 1689** [extended result code]. ^The third parameter passed to the logger is 1690** log message after formatting via [sqlite3_snprintf()]. 1691** The SQLite logging interface is not reentrant; the logger function 1692** supplied by the application must not invoke any SQLite interface. 1693** In a multi-threaded application, the application-defined logger 1694** function must be threadsafe. </dd> 1695** 1696** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1697** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1698** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1699** then URI handling is globally disabled.)^ ^If URI handling is globally 1700** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1701** [sqlite3_open16()] or 1702** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1703** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1704** connection is opened. ^If it is globally disabled, filenames are 1705** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1706** database connection is opened. ^(By default, URI handling is globally 1707** disabled. The default value may be changed by compiling with the 1708** [SQLITE_USE_URI] symbol defined.)^ 1709** 1710** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1711** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1712** argument which is interpreted as a boolean in order to enable or disable 1713** the use of covering indices for full table scans in the query optimizer. 1714** ^The default setting is determined 1715** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1716** if that compile-time option is omitted. 1717** The ability to disable the use of covering indices for full table scans 1718** is because some incorrectly coded legacy applications might malfunction 1719** when the optimization is enabled. Providing the ability to 1720** disable the optimization allows the older, buggy application code to work 1721** without change even with newer versions of SQLite. 1722** 1723** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1724** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1725** <dd> These options are obsolete and should not be used by new code. 1726** They are retained for backwards compatibility but are now no-ops. 1727** </dd> 1728** 1729** [[SQLITE_CONFIG_SQLLOG]] 1730** <dt>SQLITE_CONFIG_SQLLOG 1731** <dd>This option is only available if sqlite is compiled with the 1732** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1733** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1734** The second should be of type (void*). The callback is invoked by the library 1735** in three separate circumstances, identified by the value passed as the 1736** fourth parameter. If the fourth parameter is 0, then the database connection 1737** passed as the second argument has just been opened. The third argument 1738** points to a buffer containing the name of the main database file. If the 1739** fourth parameter is 1, then the SQL statement that the third parameter 1740** points to has just been executed. Or, if the fourth parameter is 2, then 1741** the connection being passed as the second parameter is being closed. The 1742** third parameter is passed NULL In this case. An example of using this 1743** configuration option can be seen in the "test_sqllog.c" source file in 1744** the canonical SQLite source tree.</dd> 1745** 1746** [[SQLITE_CONFIG_MMAP_SIZE]] 1747** <dt>SQLITE_CONFIG_MMAP_SIZE 1748** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1749** that are the default mmap size limit (the default setting for 1750** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1751** ^The default setting can be overridden by each database connection using 1752** either the [PRAGMA mmap_size] command, or by using the 1753** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1754** will be silently truncated if necessary so that it does not exceed the 1755** compile-time maximum mmap size set by the 1756** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1757** ^If either argument to this option is negative, then that argument is 1758** changed to its compile-time default. 1759** 1760** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1761** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1762** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1763** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1764** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1765** that specifies the maximum size of the created heap. 1766** 1767** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1768** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1769** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1770** is a pointer to an integer and writes into that integer the number of extra 1771** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1772** The amount of extra space required can change depending on the compiler, 1773** target platform, and SQLite version. 1774** 1775** [[SQLITE_CONFIG_PMASZ]] 1776** <dt>SQLITE_CONFIG_PMASZ 1777** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1778** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1779** sorter to that integer. The default minimum PMA Size is set by the 1780** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1781** to help with sort operations when multithreaded sorting 1782** is enabled (using the [PRAGMA threads] command) and the amount of content 1783** to be sorted exceeds the page size times the minimum of the 1784** [PRAGMA cache_size] setting and this value. 1785** </dl> 1786*/ 1787#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1788#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1789#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1790#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1791#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1792#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1793#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1794#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1795#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1796#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1797#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1798/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1799#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1800#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1801#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1802#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1803#define SQLITE_CONFIG_URI 17 /* int */ 1804#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1805#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1806#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1807#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1808#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1809#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1810#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1811#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1812 1813/* 1814** CAPI3REF: Database Connection Configuration Options 1815** 1816** These constants are the available integer configuration options that 1817** can be passed as the second argument to the [sqlite3_db_config()] interface. 1818** 1819** New configuration options may be added in future releases of SQLite. 1820** Existing configuration options might be discontinued. Applications 1821** should check the return code from [sqlite3_db_config()] to make sure that 1822** the call worked. ^The [sqlite3_db_config()] interface will return a 1823** non-zero [error code] if a discontinued or unsupported configuration option 1824** is invoked. 1825** 1826** <dl> 1827** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1828** <dd> ^This option takes three additional arguments that determine the 1829** [lookaside memory allocator] configuration for the [database connection]. 1830** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1831** pointer to a memory buffer to use for lookaside memory. 1832** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1833** may be NULL in which case SQLite will allocate the 1834** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1835** size of each lookaside buffer slot. ^The third argument is the number of 1836** slots. The size of the buffer in the first argument must be greater than 1837** or equal to the product of the second and third arguments. The buffer 1838** must be aligned to an 8-byte boundary. ^If the second argument to 1839** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1840** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1841** configuration for a database connection can only be changed when that 1842** connection is not currently using lookaside memory, or in other words 1843** when the "current value" returned by 1844** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1845** Any attempt to change the lookaside memory configuration when lookaside 1846** memory is in use leaves the configuration unchanged and returns 1847** [SQLITE_BUSY].)^</dd> 1848** 1849** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1850** <dd> ^This option is used to enable or disable the enforcement of 1851** [foreign key constraints]. There should be two additional arguments. 1852** The first argument is an integer which is 0 to disable FK enforcement, 1853** positive to enable FK enforcement or negative to leave FK enforcement 1854** unchanged. The second parameter is a pointer to an integer into which 1855** is written 0 or 1 to indicate whether FK enforcement is off or on 1856** following this call. The second parameter may be a NULL pointer, in 1857** which case the FK enforcement setting is not reported back. </dd> 1858** 1859** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1860** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1861** There should be two additional arguments. 1862** The first argument is an integer which is 0 to disable triggers, 1863** positive to enable triggers or negative to leave the setting unchanged. 1864** The second parameter is a pointer to an integer into which 1865** is written 0 or 1 to indicate whether triggers are disabled or enabled 1866** following this call. The second parameter may be a NULL pointer, in 1867** which case the trigger setting is not reported back. </dd> 1868** 1869** </dl> 1870*/ 1871#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1872#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1873#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1874 1875 1876/* 1877** CAPI3REF: Enable Or Disable Extended Result Codes 1878** 1879** ^The sqlite3_extended_result_codes() routine enables or disables the 1880** [extended result codes] feature of SQLite. ^The extended result 1881** codes are disabled by default for historical compatibility. 1882*/ 1883SQLITE_API int SQLITE_STDCALL sqlite3_extended_result_codes(sqlite3*, int onoff); 1884 1885/* 1886** CAPI3REF: Last Insert Rowid 1887** 1888** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 1889** has a unique 64-bit signed 1890** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1891** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1892** names are not also used by explicitly declared columns. ^If 1893** the table has a column of type [INTEGER PRIMARY KEY] then that column 1894** is another alias for the rowid. 1895** 1896** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the 1897** most recent successful [INSERT] into a rowid table or [virtual table] 1898** on database connection D. 1899** ^Inserts into [WITHOUT ROWID] tables are not recorded. 1900** ^If no successful [INSERT]s into rowid tables 1901** have ever occurred on the database connection D, 1902** then sqlite3_last_insert_rowid(D) returns zero. 1903** 1904** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1905** method, then this routine will return the [rowid] of the inserted 1906** row as long as the trigger or virtual table method is running. 1907** But once the trigger or virtual table method ends, the value returned 1908** by this routine reverts to what it was before the trigger or virtual 1909** table method began.)^ 1910** 1911** ^An [INSERT] that fails due to a constraint violation is not a 1912** successful [INSERT] and does not change the value returned by this 1913** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1914** and INSERT OR ABORT make no changes to the return value of this 1915** routine when their insertion fails. ^(When INSERT OR REPLACE 1916** encounters a constraint violation, it does not fail. The 1917** INSERT continues to completion after deleting rows that caused 1918** the constraint problem so INSERT OR REPLACE will always change 1919** the return value of this interface.)^ 1920** 1921** ^For the purposes of this routine, an [INSERT] is considered to 1922** be successful even if it is subsequently rolled back. 1923** 1924** This function is accessible to SQL statements via the 1925** [last_insert_rowid() SQL function]. 1926** 1927** If a separate thread performs a new [INSERT] on the same 1928** database connection while the [sqlite3_last_insert_rowid()] 1929** function is running and thus changes the last insert [rowid], 1930** then the value returned by [sqlite3_last_insert_rowid()] is 1931** unpredictable and might not equal either the old or the new 1932** last insert [rowid]. 1933*/ 1934SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_last_insert_rowid(sqlite3*); 1935 1936/* 1937** CAPI3REF: Count The Number Of Rows Modified 1938** 1939** ^This function returns the number of rows modified, inserted or 1940** deleted by the most recently completed INSERT, UPDATE or DELETE 1941** statement on the database connection specified by the only parameter. 1942** ^Executing any other type of SQL statement does not modify the value 1943** returned by this function. 1944** 1945** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 1946** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 1947** [foreign key actions] or [REPLACE] constraint resolution are not counted. 1948** 1949** Changes to a view that are intercepted by 1950** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 1951** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 1952** DELETE statement run on a view is always zero. Only changes made to real 1953** tables are counted. 1954** 1955** Things are more complicated if the sqlite3_changes() function is 1956** executed while a trigger program is running. This may happen if the 1957** program uses the [changes() SQL function], or if some other callback 1958** function invokes sqlite3_changes() directly. Essentially: 1959** 1960** <ul> 1961** <li> ^(Before entering a trigger program the value returned by 1962** sqlite3_changes() function is saved. After the trigger program 1963** has finished, the original value is restored.)^ 1964** 1965** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 1966** statement sets the value returned by sqlite3_changes() 1967** upon completion as normal. Of course, this value will not include 1968** any changes performed by sub-triggers, as the sqlite3_changes() 1969** value will be saved and restored after each sub-trigger has run.)^ 1970** </ul> 1971** 1972** ^This means that if the changes() SQL function (or similar) is used 1973** by the first INSERT, UPDATE or DELETE statement within a trigger, it 1974** returns the value as set when the calling statement began executing. 1975** ^If it is used by the second or subsequent such statement within a trigger 1976** program, the value returned reflects the number of rows modified by the 1977** previous INSERT, UPDATE or DELETE statement within the same trigger. 1978** 1979** See also the [sqlite3_total_changes()] interface, the 1980** [count_changes pragma], and the [changes() SQL function]. 1981** 1982** If a separate thread makes changes on the same database connection 1983** while [sqlite3_changes()] is running then the value returned 1984** is unpredictable and not meaningful. 1985*/ 1986SQLITE_API int SQLITE_STDCALL sqlite3_changes(sqlite3*); 1987 1988/* 1989** CAPI3REF: Total Number Of Rows Modified 1990** 1991** ^This function returns the total number of rows inserted, modified or 1992** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 1993** since the database connection was opened, including those executed as 1994** part of trigger programs. ^Executing any other type of SQL statement 1995** does not affect the value returned by sqlite3_total_changes(). 1996** 1997** ^Changes made as part of [foreign key actions] are included in the 1998** count, but those made as part of REPLACE constraint resolution are 1999** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2000** are not counted. 2001** 2002** See also the [sqlite3_changes()] interface, the 2003** [count_changes pragma], and the [total_changes() SQL function]. 2004** 2005** If a separate thread makes changes on the same database connection 2006** while [sqlite3_total_changes()] is running then the value 2007** returned is unpredictable and not meaningful. 2008*/ 2009SQLITE_API int SQLITE_STDCALL sqlite3_total_changes(sqlite3*); 2010 2011/* 2012** CAPI3REF: Interrupt A Long-Running Query 2013** 2014** ^This function causes any pending database operation to abort and 2015** return at its earliest opportunity. This routine is typically 2016** called in response to a user action such as pressing "Cancel" 2017** or Ctrl-C where the user wants a long query operation to halt 2018** immediately. 2019** 2020** ^It is safe to call this routine from a thread different from the 2021** thread that is currently running the database operation. But it 2022** is not safe to call this routine with a [database connection] that 2023** is closed or might close before sqlite3_interrupt() returns. 2024** 2025** ^If an SQL operation is very nearly finished at the time when 2026** sqlite3_interrupt() is called, then it might not have an opportunity 2027** to be interrupted and might continue to completion. 2028** 2029** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2030** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2031** that is inside an explicit transaction, then the entire transaction 2032** will be rolled back automatically. 2033** 2034** ^The sqlite3_interrupt(D) call is in effect until all currently running 2035** SQL statements on [database connection] D complete. ^Any new SQL statements 2036** that are started after the sqlite3_interrupt() call and before the 2037** running statements reaches zero are interrupted as if they had been 2038** running prior to the sqlite3_interrupt() call. ^New SQL statements 2039** that are started after the running statement count reaches zero are 2040** not effected by the sqlite3_interrupt(). 2041** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2042** SQL statements is a no-op and has no effect on SQL statements 2043** that are started after the sqlite3_interrupt() call returns. 2044** 2045** If the database connection closes while [sqlite3_interrupt()] 2046** is running then bad things will likely happen. 2047*/ 2048SQLITE_API void SQLITE_STDCALL sqlite3_interrupt(sqlite3*); 2049 2050/* 2051** CAPI3REF: Determine If An SQL Statement Is Complete 2052** 2053** These routines are useful during command-line input to determine if the 2054** currently entered text seems to form a complete SQL statement or 2055** if additional input is needed before sending the text into 2056** SQLite for parsing. ^These routines return 1 if the input string 2057** appears to be a complete SQL statement. ^A statement is judged to be 2058** complete if it ends with a semicolon token and is not a prefix of a 2059** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2060** string literals or quoted identifier names or comments are not 2061** independent tokens (they are part of the token in which they are 2062** embedded) and thus do not count as a statement terminator. ^Whitespace 2063** and comments that follow the final semicolon are ignored. 2064** 2065** ^These routines return 0 if the statement is incomplete. ^If a 2066** memory allocation fails, then SQLITE_NOMEM is returned. 2067** 2068** ^These routines do not parse the SQL statements thus 2069** will not detect syntactically incorrect SQL. 2070** 2071** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2072** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2073** automatically by sqlite3_complete16(). If that initialization fails, 2074** then the return value from sqlite3_complete16() will be non-zero 2075** regardless of whether or not the input SQL is complete.)^ 2076** 2077** The input to [sqlite3_complete()] must be a zero-terminated 2078** UTF-8 string. 2079** 2080** The input to [sqlite3_complete16()] must be a zero-terminated 2081** UTF-16 string in native byte order. 2082*/ 2083SQLITE_API int SQLITE_STDCALL sqlite3_complete(const char *sql); 2084SQLITE_API int SQLITE_STDCALL sqlite3_complete16(const void *sql); 2085 2086/* 2087** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2088** KEYWORDS: {busy-handler callback} {busy handler} 2089** 2090** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2091** that might be invoked with argument P whenever 2092** an attempt is made to access a database table associated with 2093** [database connection] D when another thread 2094** or process has the table locked. 2095** The sqlite3_busy_handler() interface is used to implement 2096** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2097** 2098** ^If the busy callback is NULL, then [SQLITE_BUSY] 2099** is returned immediately upon encountering the lock. ^If the busy callback 2100** is not NULL, then the callback might be invoked with two arguments. 2101** 2102** ^The first argument to the busy handler is a copy of the void* pointer which 2103** is the third argument to sqlite3_busy_handler(). ^The second argument to 2104** the busy handler callback is the number of times that the busy handler has 2105** been invoked previously for the same locking event. ^If the 2106** busy callback returns 0, then no additional attempts are made to 2107** access the database and [SQLITE_BUSY] is returned 2108** to the application. 2109** ^If the callback returns non-zero, then another attempt 2110** is made to access the database and the cycle repeats. 2111** 2112** The presence of a busy handler does not guarantee that it will be invoked 2113** when there is lock contention. ^If SQLite determines that invoking the busy 2114** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2115** to the application instead of invoking the 2116** busy handler. 2117** Consider a scenario where one process is holding a read lock that 2118** it is trying to promote to a reserved lock and 2119** a second process is holding a reserved lock that it is trying 2120** to promote to an exclusive lock. The first process cannot proceed 2121** because it is blocked by the second and the second process cannot 2122** proceed because it is blocked by the first. If both processes 2123** invoke the busy handlers, neither will make any progress. Therefore, 2124** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2125** will induce the first process to release its read lock and allow 2126** the second process to proceed. 2127** 2128** ^The default busy callback is NULL. 2129** 2130** ^(There can only be a single busy handler defined for each 2131** [database connection]. Setting a new busy handler clears any 2132** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2133** or evaluating [PRAGMA busy_timeout=N] will change the 2134** busy handler and thus clear any previously set busy handler. 2135** 2136** The busy callback should not take any actions which modify the 2137** database connection that invoked the busy handler. In other words, 2138** the busy handler is not reentrant. Any such actions 2139** result in undefined behavior. 2140** 2141** A busy handler must not close the database connection 2142** or [prepared statement] that invoked the busy handler. 2143*/ 2144SQLITE_API int SQLITE_STDCALL sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2145 2146/* 2147** CAPI3REF: Set A Busy Timeout 2148** 2149** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2150** for a specified amount of time when a table is locked. ^The handler 2151** will sleep multiple times until at least "ms" milliseconds of sleeping 2152** have accumulated. ^After at least "ms" milliseconds of sleeping, 2153** the handler returns 0 which causes [sqlite3_step()] to return 2154** [SQLITE_BUSY]. 2155** 2156** ^Calling this routine with an argument less than or equal to zero 2157** turns off all busy handlers. 2158** 2159** ^(There can only be a single busy handler for a particular 2160** [database connection] at any given moment. If another busy handler 2161** was defined (using [sqlite3_busy_handler()]) prior to calling 2162** this routine, that other busy handler is cleared.)^ 2163** 2164** See also: [PRAGMA busy_timeout] 2165*/ 2166SQLITE_API int SQLITE_STDCALL sqlite3_busy_timeout(sqlite3*, int ms); 2167 2168/* 2169** CAPI3REF: Convenience Routines For Running Queries 2170** 2171** This is a legacy interface that is preserved for backwards compatibility. 2172** Use of this interface is not recommended. 2173** 2174** Definition: A <b>result table</b> is memory data structure created by the 2175** [sqlite3_get_table()] interface. A result table records the 2176** complete query results from one or more queries. 2177** 2178** The table conceptually has a number of rows and columns. But 2179** these numbers are not part of the result table itself. These 2180** numbers are obtained separately. Let N be the number of rows 2181** and M be the number of columns. 2182** 2183** A result table is an array of pointers to zero-terminated UTF-8 strings. 2184** There are (N+1)*M elements in the array. The first M pointers point 2185** to zero-terminated strings that contain the names of the columns. 2186** The remaining entries all point to query results. NULL values result 2187** in NULL pointers. All other values are in their UTF-8 zero-terminated 2188** string representation as returned by [sqlite3_column_text()]. 2189** 2190** A result table might consist of one or more memory allocations. 2191** It is not safe to pass a result table directly to [sqlite3_free()]. 2192** A result table should be deallocated using [sqlite3_free_table()]. 2193** 2194** ^(As an example of the result table format, suppose a query result 2195** is as follows: 2196** 2197** <blockquote><pre> 2198** Name | Age 2199** ----------------------- 2200** Alice | 43 2201** Bob | 28 2202** Cindy | 21 2203** </pre></blockquote> 2204** 2205** There are two column (M==2) and three rows (N==3). Thus the 2206** result table has 8 entries. Suppose the result table is stored 2207** in an array names azResult. Then azResult holds this content: 2208** 2209** <blockquote><pre> 2210** azResult[0] = "Name"; 2211** azResult[1] = "Age"; 2212** azResult[2] = "Alice"; 2213** azResult[3] = "43"; 2214** azResult[4] = "Bob"; 2215** azResult[5] = "28"; 2216** azResult[6] = "Cindy"; 2217** azResult[7] = "21"; 2218** </pre></blockquote>)^ 2219** 2220** ^The sqlite3_get_table() function evaluates one or more 2221** semicolon-separated SQL statements in the zero-terminated UTF-8 2222** string of its 2nd parameter and returns a result table to the 2223** pointer given in its 3rd parameter. 2224** 2225** After the application has finished with the result from sqlite3_get_table(), 2226** it must pass the result table pointer to sqlite3_free_table() in order to 2227** release the memory that was malloced. Because of the way the 2228** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2229** function must not try to call [sqlite3_free()] directly. Only 2230** [sqlite3_free_table()] is able to release the memory properly and safely. 2231** 2232** The sqlite3_get_table() interface is implemented as a wrapper around 2233** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2234** to any internal data structures of SQLite. It uses only the public 2235** interface defined here. As a consequence, errors that occur in the 2236** wrapper layer outside of the internal [sqlite3_exec()] call are not 2237** reflected in subsequent calls to [sqlite3_errcode()] or 2238** [sqlite3_errmsg()]. 2239*/ 2240SQLITE_API int SQLITE_STDCALL sqlite3_get_table( 2241 sqlite3 *db, /* An open database */ 2242 const char *zSql, /* SQL to be evaluated */ 2243 char ***pazResult, /* Results of the query */ 2244 int *pnRow, /* Number of result rows written here */ 2245 int *pnColumn, /* Number of result columns written here */ 2246 char **pzErrmsg /* Error msg written here */ 2247); 2248SQLITE_API void SQLITE_STDCALL sqlite3_free_table(char **result); 2249 2250/* 2251** CAPI3REF: Formatted String Printing Functions 2252** 2253** These routines are work-alikes of the "printf()" family of functions 2254** from the standard C library. 2255** These routines understand most of the common K&R formatting options, 2256** plus some additional non-standard formats, detailed below. 2257** Note that some of the more obscure formatting options from recent 2258** C-library standards are omitted from this implementation. 2259** 2260** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2261** results into memory obtained from [sqlite3_malloc()]. 2262** The strings returned by these two routines should be 2263** released by [sqlite3_free()]. ^Both routines return a 2264** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2265** memory to hold the resulting string. 2266** 2267** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2268** the standard C library. The result is written into the 2269** buffer supplied as the second parameter whose size is given by 2270** the first parameter. Note that the order of the 2271** first two parameters is reversed from snprintf().)^ This is an 2272** historical accident that cannot be fixed without breaking 2273** backwards compatibility. ^(Note also that sqlite3_snprintf() 2274** returns a pointer to its buffer instead of the number of 2275** characters actually written into the buffer.)^ We admit that 2276** the number of characters written would be a more useful return 2277** value but we cannot change the implementation of sqlite3_snprintf() 2278** now without breaking compatibility. 2279** 2280** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2281** guarantees that the buffer is always zero-terminated. ^The first 2282** parameter "n" is the total size of the buffer, including space for 2283** the zero terminator. So the longest string that can be completely 2284** written will be n-1 characters. 2285** 2286** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2287** 2288** These routines all implement some additional formatting 2289** options that are useful for constructing SQL statements. 2290** All of the usual printf() formatting options apply. In addition, there 2291** is are "%q", "%Q", "%w" and "%z" options. 2292** 2293** ^(The %q option works like %s in that it substitutes a nul-terminated 2294** string from the argument list. But %q also doubles every '\'' character. 2295** %q is designed for use inside a string literal.)^ By doubling each '\'' 2296** character it escapes that character and allows it to be inserted into 2297** the string. 2298** 2299** For example, assume the string variable zText contains text as follows: 2300** 2301** <blockquote><pre> 2302** char *zText = "It's a happy day!"; 2303** </pre></blockquote> 2304** 2305** One can use this text in an SQL statement as follows: 2306** 2307** <blockquote><pre> 2308** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2309** sqlite3_exec(db, zSQL, 0, 0, 0); 2310** sqlite3_free(zSQL); 2311** </pre></blockquote> 2312** 2313** Because the %q format string is used, the '\'' character in zText 2314** is escaped and the SQL generated is as follows: 2315** 2316** <blockquote><pre> 2317** INSERT INTO table1 VALUES('It''s a happy day!') 2318** </pre></blockquote> 2319** 2320** This is correct. Had we used %s instead of %q, the generated SQL 2321** would have looked like this: 2322** 2323** <blockquote><pre> 2324** INSERT INTO table1 VALUES('It's a happy day!'); 2325** </pre></blockquote> 2326** 2327** This second example is an SQL syntax error. As a general rule you should 2328** always use %q instead of %s when inserting text into a string literal. 2329** 2330** ^(The %Q option works like %q except it also adds single quotes around 2331** the outside of the total string. Additionally, if the parameter in the 2332** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2333** single quotes).)^ So, for example, one could say: 2334** 2335** <blockquote><pre> 2336** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2337** sqlite3_exec(db, zSQL, 0, 0, 0); 2338** sqlite3_free(zSQL); 2339** </pre></blockquote> 2340** 2341** The code above will render a correct SQL statement in the zSQL 2342** variable even if the zText variable is a NULL pointer. 2343** 2344** ^(The "%w" formatting option is like "%q" except that it expects to 2345** be contained within double-quotes instead of single quotes, and it 2346** escapes the double-quote character instead of the single-quote 2347** character.)^ The "%w" formatting option is intended for safely inserting 2348** table and column names into a constructed SQL statement. 2349** 2350** ^(The "%z" formatting option works like "%s" but with the 2351** addition that after the string has been read and copied into 2352** the result, [sqlite3_free()] is called on the input string.)^ 2353*/ 2354SQLITE_API char *SQLITE_CDECL sqlite3_mprintf(const char*,...); 2355SQLITE_API char *SQLITE_STDCALL sqlite3_vmprintf(const char*, va_list); 2356SQLITE_API char *SQLITE_CDECL sqlite3_snprintf(int,char*,const char*, ...); 2357SQLITE_API char *SQLITE_STDCALL sqlite3_vsnprintf(int,char*,const char*, va_list); 2358 2359/* 2360** CAPI3REF: Memory Allocation Subsystem 2361** 2362** The SQLite core uses these three routines for all of its own 2363** internal memory allocation needs. "Core" in the previous sentence 2364** does not include operating-system specific VFS implementation. The 2365** Windows VFS uses native malloc() and free() for some operations. 2366** 2367** ^The sqlite3_malloc() routine returns a pointer to a block 2368** of memory at least N bytes in length, where N is the parameter. 2369** ^If sqlite3_malloc() is unable to obtain sufficient free 2370** memory, it returns a NULL pointer. ^If the parameter N to 2371** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2372** a NULL pointer. 2373** 2374** ^The sqlite3_malloc64(N) routine works just like 2375** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2376** of a signed 32-bit integer. 2377** 2378** ^Calling sqlite3_free() with a pointer previously returned 2379** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2380** that it might be reused. ^The sqlite3_free() routine is 2381** a no-op if is called with a NULL pointer. Passing a NULL pointer 2382** to sqlite3_free() is harmless. After being freed, memory 2383** should neither be read nor written. Even reading previously freed 2384** memory might result in a segmentation fault or other severe error. 2385** Memory corruption, a segmentation fault, or other severe error 2386** might result if sqlite3_free() is called with a non-NULL pointer that 2387** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2388** 2389** ^The sqlite3_realloc(X,N) interface attempts to resize a 2390** prior memory allocation X to be at least N bytes. 2391** ^If the X parameter to sqlite3_realloc(X,N) 2392** is a NULL pointer then its behavior is identical to calling 2393** sqlite3_malloc(N). 2394** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2395** negative then the behavior is exactly the same as calling 2396** sqlite3_free(X). 2397** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2398** of at least N bytes in size or NULL if insufficient memory is available. 2399** ^If M is the size of the prior allocation, then min(N,M) bytes 2400** of the prior allocation are copied into the beginning of buffer returned 2401** by sqlite3_realloc(X,N) and the prior allocation is freed. 2402** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2403** prior allocation is not freed. 2404** 2405** ^The sqlite3_realloc64(X,N) interfaces works the same as 2406** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2407** of a 32-bit signed integer. 2408** 2409** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2410** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2411** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2412** ^The value returned by sqlite3_msize(X) might be larger than the number 2413** of bytes requested when X was allocated. ^If X is a NULL pointer then 2414** sqlite3_msize(X) returns zero. If X points to something that is not 2415** the beginning of memory allocation, or if it points to a formerly 2416** valid memory allocation that has now been freed, then the behavior 2417** of sqlite3_msize(X) is undefined and possibly harmful. 2418** 2419** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2420** sqlite3_malloc64(), and sqlite3_realloc64() 2421** is always aligned to at least an 8 byte boundary, or to a 2422** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2423** option is used. 2424** 2425** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2426** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2427** implementation of these routines to be omitted. That capability 2428** is no longer provided. Only built-in memory allocators can be used. 2429** 2430** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2431** the system malloc() and free() directly when converting 2432** filenames between the UTF-8 encoding used by SQLite 2433** and whatever filename encoding is used by the particular Windows 2434** installation. Memory allocation errors were detected, but 2435** they were reported back as [SQLITE_CANTOPEN] or 2436** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2437** 2438** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2439** must be either NULL or else pointers obtained from a prior 2440** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2441** not yet been released. 2442** 2443** The application must not read or write any part of 2444** a block of memory after it has been released using 2445** [sqlite3_free()] or [sqlite3_realloc()]. 2446*/ 2447SQLITE_API void *SQLITE_STDCALL sqlite3_malloc(int); 2448SQLITE_API void *SQLITE_STDCALL sqlite3_malloc64(sqlite3_uint64); 2449SQLITE_API void *SQLITE_STDCALL sqlite3_realloc(void*, int); 2450SQLITE_API void *SQLITE_STDCALL sqlite3_realloc64(void*, sqlite3_uint64); 2451SQLITE_API void SQLITE_STDCALL sqlite3_free(void*); 2452SQLITE_API sqlite3_uint64 SQLITE_STDCALL sqlite3_msize(void*); 2453 2454/* 2455** CAPI3REF: Memory Allocator Statistics 2456** 2457** SQLite provides these two interfaces for reporting on the status 2458** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2459** routines, which form the built-in memory allocation subsystem. 2460** 2461** ^The [sqlite3_memory_used()] routine returns the number of bytes 2462** of memory currently outstanding (malloced but not freed). 2463** ^The [sqlite3_memory_highwater()] routine returns the maximum 2464** value of [sqlite3_memory_used()] since the high-water mark 2465** was last reset. ^The values returned by [sqlite3_memory_used()] and 2466** [sqlite3_memory_highwater()] include any overhead 2467** added by SQLite in its implementation of [sqlite3_malloc()], 2468** but not overhead added by the any underlying system library 2469** routines that [sqlite3_malloc()] may call. 2470** 2471** ^The memory high-water mark is reset to the current value of 2472** [sqlite3_memory_used()] if and only if the parameter to 2473** [sqlite3_memory_highwater()] is true. ^The value returned 2474** by [sqlite3_memory_highwater(1)] is the high-water mark 2475** prior to the reset. 2476*/ 2477SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_used(void); 2478SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_highwater(int resetFlag); 2479 2480/* 2481** CAPI3REF: Pseudo-Random Number Generator 2482** 2483** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2484** select random [ROWID | ROWIDs] when inserting new records into a table that 2485** already uses the largest possible [ROWID]. The PRNG is also used for 2486** the build-in random() and randomblob() SQL functions. This interface allows 2487** applications to access the same PRNG for other purposes. 2488** 2489** ^A call to this routine stores N bytes of randomness into buffer P. 2490** ^The P parameter can be a NULL pointer. 2491** 2492** ^If this routine has not been previously called or if the previous 2493** call had N less than one or a NULL pointer for P, then the PRNG is 2494** seeded using randomness obtained from the xRandomness method of 2495** the default [sqlite3_vfs] object. 2496** ^If the previous call to this routine had an N of 1 or more and a 2497** non-NULL P then the pseudo-randomness is generated 2498** internally and without recourse to the [sqlite3_vfs] xRandomness 2499** method. 2500*/ 2501SQLITE_API void SQLITE_STDCALL sqlite3_randomness(int N, void *P); 2502 2503/* 2504** CAPI3REF: Compile-Time Authorization Callbacks 2505** 2506** ^This routine registers an authorizer callback with a particular 2507** [database connection], supplied in the first argument. 2508** ^The authorizer callback is invoked as SQL statements are being compiled 2509** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2510** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2511** points during the compilation process, as logic is being created 2512** to perform various actions, the authorizer callback is invoked to 2513** see if those actions are allowed. ^The authorizer callback should 2514** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2515** specific action but allow the SQL statement to continue to be 2516** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2517** rejected with an error. ^If the authorizer callback returns 2518** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2519** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2520** the authorizer will fail with an error message. 2521** 2522** When the callback returns [SQLITE_OK], that means the operation 2523** requested is ok. ^When the callback returns [SQLITE_DENY], the 2524** [sqlite3_prepare_v2()] or equivalent call that triggered the 2525** authorizer will fail with an error message explaining that 2526** access is denied. 2527** 2528** ^The first parameter to the authorizer callback is a copy of the third 2529** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2530** to the callback is an integer [SQLITE_COPY | action code] that specifies 2531** the particular action to be authorized. ^The third through sixth parameters 2532** to the callback are zero-terminated strings that contain additional 2533** details about the action to be authorized. 2534** 2535** ^If the action code is [SQLITE_READ] 2536** and the callback returns [SQLITE_IGNORE] then the 2537** [prepared statement] statement is constructed to substitute 2538** a NULL value in place of the table column that would have 2539** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2540** return can be used to deny an untrusted user access to individual 2541** columns of a table. 2542** ^If the action code is [SQLITE_DELETE] and the callback returns 2543** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2544** [truncate optimization] is disabled and all rows are deleted individually. 2545** 2546** An authorizer is used when [sqlite3_prepare | preparing] 2547** SQL statements from an untrusted source, to ensure that the SQL statements 2548** do not try to access data they are not allowed to see, or that they do not 2549** try to execute malicious statements that damage the database. For 2550** example, an application may allow a user to enter arbitrary 2551** SQL queries for evaluation by a database. But the application does 2552** not want the user to be able to make arbitrary changes to the 2553** database. An authorizer could then be put in place while the 2554** user-entered SQL is being [sqlite3_prepare | prepared] that 2555** disallows everything except [SELECT] statements. 2556** 2557** Applications that need to process SQL from untrusted sources 2558** might also consider lowering resource limits using [sqlite3_limit()] 2559** and limiting database size using the [max_page_count] [PRAGMA] 2560** in addition to using an authorizer. 2561** 2562** ^(Only a single authorizer can be in place on a database connection 2563** at a time. Each call to sqlite3_set_authorizer overrides the 2564** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2565** The authorizer is disabled by default. 2566** 2567** The authorizer callback must not do anything that will modify 2568** the database connection that invoked the authorizer callback. 2569** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2570** database connections for the meaning of "modify" in this paragraph. 2571** 2572** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2573** statement might be re-prepared during [sqlite3_step()] due to a 2574** schema change. Hence, the application should ensure that the 2575** correct authorizer callback remains in place during the [sqlite3_step()]. 2576** 2577** ^Note that the authorizer callback is invoked only during 2578** [sqlite3_prepare()] or its variants. Authorization is not 2579** performed during statement evaluation in [sqlite3_step()], unless 2580** as stated in the previous paragraph, sqlite3_step() invokes 2581** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2582*/ 2583SQLITE_API int SQLITE_STDCALL sqlite3_set_authorizer( 2584 sqlite3*, 2585 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2586 void *pUserData 2587); 2588 2589/* 2590** CAPI3REF: Authorizer Return Codes 2591** 2592** The [sqlite3_set_authorizer | authorizer callback function] must 2593** return either [SQLITE_OK] or one of these two constants in order 2594** to signal SQLite whether or not the action is permitted. See the 2595** [sqlite3_set_authorizer | authorizer documentation] for additional 2596** information. 2597** 2598** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2599** returned from the [sqlite3_vtab_on_conflict()] interface. 2600*/ 2601#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2602#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2603 2604/* 2605** CAPI3REF: Authorizer Action Codes 2606** 2607** The [sqlite3_set_authorizer()] interface registers a callback function 2608** that is invoked to authorize certain SQL statement actions. The 2609** second parameter to the callback is an integer code that specifies 2610** what action is being authorized. These are the integer action codes that 2611** the authorizer callback may be passed. 2612** 2613** These action code values signify what kind of operation is to be 2614** authorized. The 3rd and 4th parameters to the authorization 2615** callback function will be parameters or NULL depending on which of these 2616** codes is used as the second parameter. ^(The 5th parameter to the 2617** authorizer callback is the name of the database ("main", "temp", 2618** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2619** is the name of the inner-most trigger or view that is responsible for 2620** the access attempt or NULL if this access attempt is directly from 2621** top-level SQL code. 2622*/ 2623/******************************************* 3rd ************ 4th ***********/ 2624#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2625#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2626#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2627#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2628#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2629#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2630#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2631#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2632#define SQLITE_DELETE 9 /* Table Name NULL */ 2633#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2634#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2635#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2636#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2637#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2638#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2639#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2640#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2641#define SQLITE_INSERT 18 /* Table Name NULL */ 2642#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2643#define SQLITE_READ 20 /* Table Name Column Name */ 2644#define SQLITE_SELECT 21 /* NULL NULL */ 2645#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2646#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2647#define SQLITE_ATTACH 24 /* Filename NULL */ 2648#define SQLITE_DETACH 25 /* Database Name NULL */ 2649#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2650#define SQLITE_REINDEX 27 /* Index Name NULL */ 2651#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2652#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2653#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2654#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2655#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2656#define SQLITE_COPY 0 /* No longer used */ 2657#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2658 2659/* 2660** CAPI3REF: Tracing And Profiling Functions 2661** 2662** These routines register callback functions that can be used for 2663** tracing and profiling the execution of SQL statements. 2664** 2665** ^The callback function registered by sqlite3_trace() is invoked at 2666** various times when an SQL statement is being run by [sqlite3_step()]. 2667** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2668** SQL statement text as the statement first begins executing. 2669** ^(Additional sqlite3_trace() callbacks might occur 2670** as each triggered subprogram is entered. The callbacks for triggers 2671** contain a UTF-8 SQL comment that identifies the trigger.)^ 2672** 2673** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2674** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2675** 2676** ^The callback function registered by sqlite3_profile() is invoked 2677** as each SQL statement finishes. ^The profile callback contains 2678** the original statement text and an estimate of wall-clock time 2679** of how long that statement took to run. ^The profile callback 2680** time is in units of nanoseconds, however the current implementation 2681** is only capable of millisecond resolution so the six least significant 2682** digits in the time are meaningless. Future versions of SQLite 2683** might provide greater resolution on the profiler callback. The 2684** sqlite3_profile() function is considered experimental and is 2685** subject to change in future versions of SQLite. 2686*/ 2687SQLITE_API void *SQLITE_STDCALL sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2688SQLITE_API SQLITE_EXPERIMENTAL void *SQLITE_STDCALL sqlite3_profile(sqlite3*, 2689 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2690 2691/* 2692** CAPI3REF: Query Progress Callbacks 2693** 2694** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2695** function X to be invoked periodically during long running calls to 2696** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2697** database connection D. An example use for this 2698** interface is to keep a GUI updated during a large query. 2699** 2700** ^The parameter P is passed through as the only parameter to the 2701** callback function X. ^The parameter N is the approximate number of 2702** [virtual machine instructions] that are evaluated between successive 2703** invocations of the callback X. ^If N is less than one then the progress 2704** handler is disabled. 2705** 2706** ^Only a single progress handler may be defined at one time per 2707** [database connection]; setting a new progress handler cancels the 2708** old one. ^Setting parameter X to NULL disables the progress handler. 2709** ^The progress handler is also disabled by setting N to a value less 2710** than 1. 2711** 2712** ^If the progress callback returns non-zero, the operation is 2713** interrupted. This feature can be used to implement a 2714** "Cancel" button on a GUI progress dialog box. 2715** 2716** The progress handler callback must not do anything that will modify 2717** the database connection that invoked the progress handler. 2718** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2719** database connections for the meaning of "modify" in this paragraph. 2720** 2721*/ 2722SQLITE_API void SQLITE_STDCALL sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2723 2724/* 2725** CAPI3REF: Opening A New Database Connection 2726** 2727** ^These routines open an SQLite database file as specified by the 2728** filename argument. ^The filename argument is interpreted as UTF-8 for 2729** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2730** order for sqlite3_open16(). ^(A [database connection] handle is usually 2731** returned in *ppDb, even if an error occurs. The only exception is that 2732** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2733** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2734** object.)^ ^(If the database is opened (and/or created) successfully, then 2735** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2736** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2737** an English language description of the error following a failure of any 2738** of the sqlite3_open() routines. 2739** 2740** ^The default encoding will be UTF-8 for databases created using 2741** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 2742** created using sqlite3_open16() will be UTF-16 in the native byte order. 2743** 2744** Whether or not an error occurs when it is opened, resources 2745** associated with the [database connection] handle should be released by 2746** passing it to [sqlite3_close()] when it is no longer required. 2747** 2748** The sqlite3_open_v2() interface works like sqlite3_open() 2749** except that it accepts two additional parameters for additional control 2750** over the new database connection. ^(The flags parameter to 2751** sqlite3_open_v2() can take one of 2752** the following three values, optionally combined with the 2753** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2754** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2755** 2756** <dl> 2757** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2758** <dd>The database is opened in read-only mode. If the database does not 2759** already exist, an error is returned.</dd>)^ 2760** 2761** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2762** <dd>The database is opened for reading and writing if possible, or reading 2763** only if the file is write protected by the operating system. In either 2764** case the database must already exist, otherwise an error is returned.</dd>)^ 2765** 2766** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2767** <dd>The database is opened for reading and writing, and is created if 2768** it does not already exist. This is the behavior that is always used for 2769** sqlite3_open() and sqlite3_open16().</dd>)^ 2770** </dl> 2771** 2772** If the 3rd parameter to sqlite3_open_v2() is not one of the 2773** combinations shown above optionally combined with other 2774** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2775** then the behavior is undefined. 2776** 2777** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2778** opens in the multi-thread [threading mode] as long as the single-thread 2779** mode has not been set at compile-time or start-time. ^If the 2780** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2781** in the serialized [threading mode] unless single-thread was 2782** previously selected at compile-time or start-time. 2783** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2784** eligible to use [shared cache mode], regardless of whether or not shared 2785** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2786** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2787** participate in [shared cache mode] even if it is enabled. 2788** 2789** ^The fourth parameter to sqlite3_open_v2() is the name of the 2790** [sqlite3_vfs] object that defines the operating system interface that 2791** the new database connection should use. ^If the fourth parameter is 2792** a NULL pointer then the default [sqlite3_vfs] object is used. 2793** 2794** ^If the filename is ":memory:", then a private, temporary in-memory database 2795** is created for the connection. ^This in-memory database will vanish when 2796** the database connection is closed. Future versions of SQLite might 2797** make use of additional special filenames that begin with the ":" character. 2798** It is recommended that when a database filename actually does begin with 2799** a ":" character you should prefix the filename with a pathname such as 2800** "./" to avoid ambiguity. 2801** 2802** ^If the filename is an empty string, then a private, temporary 2803** on-disk database will be created. ^This private database will be 2804** automatically deleted as soon as the database connection is closed. 2805** 2806** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2807** 2808** ^If [URI filename] interpretation is enabled, and the filename argument 2809** begins with "file:", then the filename is interpreted as a URI. ^URI 2810** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2811** set in the fourth argument to sqlite3_open_v2(), or if it has 2812** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2813** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2814** As of SQLite version 3.7.7, URI filename interpretation is turned off 2815** by default, but future releases of SQLite might enable URI filename 2816** interpretation by default. See "[URI filenames]" for additional 2817** information. 2818** 2819** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2820** authority, then it must be either an empty string or the string 2821** "localhost". ^If the authority is not an empty string or "localhost", an 2822** error is returned to the caller. ^The fragment component of a URI, if 2823** present, is ignored. 2824** 2825** ^SQLite uses the path component of the URI as the name of the disk file 2826** which contains the database. ^If the path begins with a '/' character, 2827** then it is interpreted as an absolute path. ^If the path does not begin 2828** with a '/' (meaning that the authority section is omitted from the URI) 2829** then the path is interpreted as a relative path. 2830** ^(On windows, the first component of an absolute path 2831** is a drive specification (e.g. "C:").)^ 2832** 2833** [[core URI query parameters]] 2834** The query component of a URI may contain parameters that are interpreted 2835** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2836** SQLite and its built-in [VFSes] interpret the 2837** following query parameters: 2838** 2839** <ul> 2840** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2841** a VFS object that provides the operating system interface that should 2842** be used to access the database file on disk. ^If this option is set to 2843** an empty string the default VFS object is used. ^Specifying an unknown 2844** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2845** present, then the VFS specified by the option takes precedence over 2846** the value passed as the fourth parameter to sqlite3_open_v2(). 2847** 2848** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2849** "rwc", or "memory". Attempting to set it to any other value is 2850** an error)^. 2851** ^If "ro" is specified, then the database is opened for read-only 2852** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2853** third argument to sqlite3_open_v2(). ^If the mode option is set to 2854** "rw", then the database is opened for read-write (but not create) 2855** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2856** been set. ^Value "rwc" is equivalent to setting both 2857** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2858** set to "memory" then a pure [in-memory database] that never reads 2859** or writes from disk is used. ^It is an error to specify a value for 2860** the mode parameter that is less restrictive than that specified by 2861** the flags passed in the third parameter to sqlite3_open_v2(). 2862** 2863** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2864** "private". ^Setting it to "shared" is equivalent to setting the 2865** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2866** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2867** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2868** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2869** a URI filename, its value overrides any behavior requested by setting 2870** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2871** 2872** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 2873** [powersafe overwrite] property does or does not apply to the 2874** storage media on which the database file resides. 2875** 2876** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 2877** which if set disables file locking in rollback journal modes. This 2878** is useful for accessing a database on a filesystem that does not 2879** support locking. Caution: Database corruption might result if two 2880** or more processes write to the same database and any one of those 2881** processes uses nolock=1. 2882** 2883** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 2884** parameter that indicates that the database file is stored on 2885** read-only media. ^When immutable is set, SQLite assumes that the 2886** database file cannot be changed, even by a process with higher 2887** privilege, and so the database is opened read-only and all locking 2888** and change detection is disabled. Caution: Setting the immutable 2889** property on a database file that does in fact change can result 2890** in incorrect query results and/or [SQLITE_CORRUPT] errors. 2891** See also: [SQLITE_IOCAP_IMMUTABLE]. 2892** 2893** </ul> 2894** 2895** ^Specifying an unknown parameter in the query component of a URI is not an 2896** error. Future versions of SQLite might understand additional query 2897** parameters. See "[query parameters with special meaning to SQLite]" for 2898** additional information. 2899** 2900** [[URI filename examples]] <h3>URI filename examples</h3> 2901** 2902** <table border="1" align=center cellpadding=5> 2903** <tr><th> URI filenames <th> Results 2904** <tr><td> file:data.db <td> 2905** Open the file "data.db" in the current directory. 2906** <tr><td> file:/home/fred/data.db<br> 2907** file:///home/fred/data.db <br> 2908** file://localhost/home/fred/data.db <br> <td> 2909** Open the database file "/home/fred/data.db". 2910** <tr><td> file://darkstar/home/fred/data.db <td> 2911** An error. "darkstar" is not a recognized authority. 2912** <tr><td style="white-space:nowrap"> 2913** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2914** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2915** C:. Note that the %20 escaping in this example is not strictly 2916** necessary - space characters can be used literally 2917** in URI filenames. 2918** <tr><td> file:data.db?mode=ro&cache=private <td> 2919** Open file "data.db" in the current directory for read-only access. 2920** Regardless of whether or not shared-cache mode is enabled by 2921** default, use a private cache. 2922** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 2923** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 2924** that uses dot-files in place of posix advisory locking. 2925** <tr><td> file:data.db?mode=readonly <td> 2926** An error. "readonly" is not a valid option for the "mode" parameter. 2927** </table> 2928** 2929** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2930** query components of a URI. A hexadecimal escape sequence consists of a 2931** percent sign - "%" - followed by exactly two hexadecimal digits 2932** specifying an octet value. ^Before the path or query components of a 2933** URI filename are interpreted, they are encoded using UTF-8 and all 2934** hexadecimal escape sequences replaced by a single byte containing the 2935** corresponding octet. If this process generates an invalid UTF-8 encoding, 2936** the results are undefined. 2937** 2938** <b>Note to Windows users:</b> The encoding used for the filename argument 2939** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2940** codepage is currently defined. Filenames containing international 2941** characters must be converted to UTF-8 prior to passing them into 2942** sqlite3_open() or sqlite3_open_v2(). 2943** 2944** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2945** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2946** features that require the use of temporary files may fail. 2947** 2948** See also: [sqlite3_temp_directory] 2949*/ 2950SQLITE_API int SQLITE_STDCALL sqlite3_open( 2951 const char *filename, /* Database filename (UTF-8) */ 2952 sqlite3 **ppDb /* OUT: SQLite db handle */ 2953); 2954SQLITE_API int SQLITE_STDCALL sqlite3_open16( 2955 const void *filename, /* Database filename (UTF-16) */ 2956 sqlite3 **ppDb /* OUT: SQLite db handle */ 2957); 2958SQLITE_API int SQLITE_STDCALL sqlite3_open_v2( 2959 const char *filename, /* Database filename (UTF-8) */ 2960 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2961 int flags, /* Flags */ 2962 const char *zVfs /* Name of VFS module to use */ 2963); 2964 2965/* 2966** CAPI3REF: Obtain Values For URI Parameters 2967** 2968** These are utility routines, useful to VFS implementations, that check 2969** to see if a database file was a URI that contained a specific query 2970** parameter, and if so obtains the value of that query parameter. 2971** 2972** If F is the database filename pointer passed into the xOpen() method of 2973** a VFS implementation when the flags parameter to xOpen() has one or 2974** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2975** P is the name of the query parameter, then 2976** sqlite3_uri_parameter(F,P) returns the value of the P 2977** parameter if it exists or a NULL pointer if P does not appear as a 2978** query parameter on F. If P is a query parameter of F 2979** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2980** a pointer to an empty string. 2981** 2982** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2983** parameter and returns true (1) or false (0) according to the value 2984** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2985** value of query parameter P is one of "yes", "true", or "on" in any 2986** case or if the value begins with a non-zero number. The 2987** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2988** query parameter P is one of "no", "false", or "off" in any case or 2989** if the value begins with a numeric zero. If P is not a query 2990** parameter on F or if the value of P is does not match any of the 2991** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2992** 2993** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2994** 64-bit signed integer and returns that integer, or D if P does not 2995** exist. If the value of P is something other than an integer, then 2996** zero is returned. 2997** 2998** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2999** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3000** is not a database file pathname pointer that SQLite passed into the xOpen 3001** VFS method, then the behavior of this routine is undefined and probably 3002** undesirable. 3003*/ 3004SQLITE_API const char *SQLITE_STDCALL sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3005SQLITE_API int SQLITE_STDCALL sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3006SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3007 3008 3009/* 3010** CAPI3REF: Error Codes And Messages 3011** 3012** ^If the most recent sqlite3_* API call associated with 3013** [database connection] D failed, then the sqlite3_errcode(D) interface 3014** returns the numeric [result code] or [extended result code] for that 3015** API call. 3016** If the most recent API call was successful, 3017** then the return value from sqlite3_errcode() is undefined. 3018** ^The sqlite3_extended_errcode() 3019** interface is the same except that it always returns the 3020** [extended result code] even when extended result codes are 3021** disabled. 3022** 3023** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3024** text that describes the error, as either UTF-8 or UTF-16 respectively. 3025** ^(Memory to hold the error message string is managed internally. 3026** The application does not need to worry about freeing the result. 3027** However, the error string might be overwritten or deallocated by 3028** subsequent calls to other SQLite interface functions.)^ 3029** 3030** ^The sqlite3_errstr() interface returns the English-language text 3031** that describes the [result code], as UTF-8. 3032** ^(Memory to hold the error message string is managed internally 3033** and must not be freed by the application)^. 3034** 3035** When the serialized [threading mode] is in use, it might be the 3036** case that a second error occurs on a separate thread in between 3037** the time of the first error and the call to these interfaces. 3038** When that happens, the second error will be reported since these 3039** interfaces always report the most recent result. To avoid 3040** this, each thread can obtain exclusive use of the [database connection] D 3041** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3042** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3043** all calls to the interfaces listed here are completed. 3044** 3045** If an interface fails with SQLITE_MISUSE, that means the interface 3046** was invoked incorrectly by the application. In that case, the 3047** error code and message may or may not be set. 3048*/ 3049SQLITE_API int SQLITE_STDCALL sqlite3_errcode(sqlite3 *db); 3050SQLITE_API int SQLITE_STDCALL sqlite3_extended_errcode(sqlite3 *db); 3051SQLITE_API const char *SQLITE_STDCALL sqlite3_errmsg(sqlite3*); 3052SQLITE_API const void *SQLITE_STDCALL sqlite3_errmsg16(sqlite3*); 3053SQLITE_API const char *SQLITE_STDCALL sqlite3_errstr(int); 3054 3055/* 3056** CAPI3REF: SQL Statement Object 3057** KEYWORDS: {prepared statement} {prepared statements} 3058** 3059** An instance of this object represents a single SQL statement. 3060** This object is variously known as a "prepared statement" or a 3061** "compiled SQL statement" or simply as a "statement". 3062** 3063** The life of a statement object goes something like this: 3064** 3065** <ol> 3066** <li> Create the object using [sqlite3_prepare_v2()] or a related 3067** function. 3068** <li> Bind values to [host parameters] using the sqlite3_bind_*() 3069** interfaces. 3070** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3071** <li> Reset the statement using [sqlite3_reset()] then go back 3072** to step 2. Do this zero or more times. 3073** <li> Destroy the object using [sqlite3_finalize()]. 3074** </ol> 3075** 3076** Refer to documentation on individual methods above for additional 3077** information. 3078*/ 3079typedef struct sqlite3_stmt sqlite3_stmt; 3080 3081/* 3082** CAPI3REF: Run-time Limits 3083** 3084** ^(This interface allows the size of various constructs to be limited 3085** on a connection by connection basis. The first parameter is the 3086** [database connection] whose limit is to be set or queried. The 3087** second parameter is one of the [limit categories] that define a 3088** class of constructs to be size limited. The third parameter is the 3089** new limit for that construct.)^ 3090** 3091** ^If the new limit is a negative number, the limit is unchanged. 3092** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3093** [limits | hard upper bound] 3094** set at compile-time by a C preprocessor macro called 3095** [limits | SQLITE_MAX_<i>NAME</i>]. 3096** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3097** ^Attempts to increase a limit above its hard upper bound are 3098** silently truncated to the hard upper bound. 3099** 3100** ^Regardless of whether or not the limit was changed, the 3101** [sqlite3_limit()] interface returns the prior value of the limit. 3102** ^Hence, to find the current value of a limit without changing it, 3103** simply invoke this interface with the third parameter set to -1. 3104** 3105** Run-time limits are intended for use in applications that manage 3106** both their own internal database and also databases that are controlled 3107** by untrusted external sources. An example application might be a 3108** web browser that has its own databases for storing history and 3109** separate databases controlled by JavaScript applications downloaded 3110** off the Internet. The internal databases can be given the 3111** large, default limits. Databases managed by external sources can 3112** be given much smaller limits designed to prevent a denial of service 3113** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3114** interface to further control untrusted SQL. The size of the database 3115** created by an untrusted script can be contained using the 3116** [max_page_count] [PRAGMA]. 3117** 3118** New run-time limit categories may be added in future releases. 3119*/ 3120SQLITE_API int SQLITE_STDCALL sqlite3_limit(sqlite3*, int id, int newVal); 3121 3122/* 3123** CAPI3REF: Run-Time Limit Categories 3124** KEYWORDS: {limit category} {*limit categories} 3125** 3126** These constants define various performance limits 3127** that can be lowered at run-time using [sqlite3_limit()]. 3128** The synopsis of the meanings of the various limits is shown below. 3129** Additional information is available at [limits | Limits in SQLite]. 3130** 3131** <dl> 3132** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3133** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3134** 3135** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3136** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3137** 3138** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3139** <dd>The maximum number of columns in a table definition or in the 3140** result set of a [SELECT] or the maximum number of columns in an index 3141** or in an ORDER BY or GROUP BY clause.</dd>)^ 3142** 3143** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3144** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3145** 3146** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3147** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3148** 3149** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3150** <dd>The maximum number of instructions in a virtual machine program 3151** used to implement an SQL statement. This limit is not currently 3152** enforced, though that might be added in some future release of 3153** SQLite.</dd>)^ 3154** 3155** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3156** <dd>The maximum number of arguments on a function.</dd>)^ 3157** 3158** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3159** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3160** 3161** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3162** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3163** <dd>The maximum length of the pattern argument to the [LIKE] or 3164** [GLOB] operators.</dd>)^ 3165** 3166** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3167** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3168** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3169** 3170** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3171** <dd>The maximum depth of recursion for triggers.</dd>)^ 3172** 3173** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3174** <dd>The maximum number of auxiliary worker threads that a single 3175** [prepared statement] may start.</dd>)^ 3176** </dl> 3177*/ 3178#define SQLITE_LIMIT_LENGTH 0 3179#define SQLITE_LIMIT_SQL_LENGTH 1 3180#define SQLITE_LIMIT_COLUMN 2 3181#define SQLITE_LIMIT_EXPR_DEPTH 3 3182#define SQLITE_LIMIT_COMPOUND_SELECT 4 3183#define SQLITE_LIMIT_VDBE_OP 5 3184#define SQLITE_LIMIT_FUNCTION_ARG 6 3185#define SQLITE_LIMIT_ATTACHED 7 3186#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3187#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3188#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3189#define SQLITE_LIMIT_WORKER_THREADS 11 3190 3191/* 3192** CAPI3REF: Compiling An SQL Statement 3193** KEYWORDS: {SQL statement compiler} 3194** 3195** To execute an SQL query, it must first be compiled into a byte-code 3196** program using one of these routines. 3197** 3198** The first argument, "db", is a [database connection] obtained from a 3199** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3200** [sqlite3_open16()]. The database connection must not have been closed. 3201** 3202** The second argument, "zSql", is the statement to be compiled, encoded 3203** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3204** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3205** use UTF-16. 3206** 3207** ^If the nByte argument is negative, then zSql is read up to the 3208** first zero terminator. ^If nByte is positive, then it is the 3209** number of bytes read from zSql. ^If nByte is zero, then no prepared 3210** statement is generated. 3211** If the caller knows that the supplied string is nul-terminated, then 3212** there is a small performance advantage to passing an nByte parameter that 3213** is the number of bytes in the input string <i>including</i> 3214** the nul-terminator. 3215** 3216** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3217** past the end of the first SQL statement in zSql. These routines only 3218** compile the first statement in zSql, so *pzTail is left pointing to 3219** what remains uncompiled. 3220** 3221** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3222** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3223** to NULL. ^If the input text contains no SQL (if the input is an empty 3224** string or a comment) then *ppStmt is set to NULL. 3225** The calling procedure is responsible for deleting the compiled 3226** SQL statement using [sqlite3_finalize()] after it has finished with it. 3227** ppStmt may not be NULL. 3228** 3229** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3230** otherwise an [error code] is returned. 3231** 3232** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3233** recommended for all new programs. The two older interfaces are retained 3234** for backwards compatibility, but their use is discouraged. 3235** ^In the "v2" interfaces, the prepared statement 3236** that is returned (the [sqlite3_stmt] object) contains a copy of the 3237** original SQL text. This causes the [sqlite3_step()] interface to 3238** behave differently in three ways: 3239** 3240** <ol> 3241** <li> 3242** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3243** always used to do, [sqlite3_step()] will automatically recompile the SQL 3244** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3245** retries will occur before sqlite3_step() gives up and returns an error. 3246** </li> 3247** 3248** <li> 3249** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3250** [error codes] or [extended error codes]. ^The legacy behavior was that 3251** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3252** and the application would have to make a second call to [sqlite3_reset()] 3253** in order to find the underlying cause of the problem. With the "v2" prepare 3254** interfaces, the underlying reason for the error is returned immediately. 3255** </li> 3256** 3257** <li> 3258** ^If the specific value bound to [parameter | host parameter] in the 3259** WHERE clause might influence the choice of query plan for a statement, 3260** then the statement will be automatically recompiled, as if there had been 3261** a schema change, on the first [sqlite3_step()] call following any change 3262** to the [sqlite3_bind_text | bindings] of that [parameter]. 3263** ^The specific value of WHERE-clause [parameter] might influence the 3264** choice of query plan if the parameter is the left-hand side of a [LIKE] 3265** or [GLOB] operator or if the parameter is compared to an indexed column 3266** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3267** </li> 3268** </ol> 3269*/ 3270SQLITE_API int SQLITE_STDCALL sqlite3_prepare( 3271 sqlite3 *db, /* Database handle */ 3272 const char *zSql, /* SQL statement, UTF-8 encoded */ 3273 int nByte, /* Maximum length of zSql in bytes. */ 3274 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3275 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3276); 3277SQLITE_API int SQLITE_STDCALL sqlite3_prepare_v2( 3278 sqlite3 *db, /* Database handle */ 3279 const char *zSql, /* SQL statement, UTF-8 encoded */ 3280 int nByte, /* Maximum length of zSql in bytes. */ 3281 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3282 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3283); 3284SQLITE_API int SQLITE_STDCALL sqlite3_prepare16( 3285 sqlite3 *db, /* Database handle */ 3286 const void *zSql, /* SQL statement, UTF-16 encoded */ 3287 int nByte, /* Maximum length of zSql in bytes. */ 3288 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3289 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3290); 3291SQLITE_API int SQLITE_STDCALL sqlite3_prepare16_v2( 3292 sqlite3 *db, /* Database handle */ 3293 const void *zSql, /* SQL statement, UTF-16 encoded */ 3294 int nByte, /* Maximum length of zSql in bytes. */ 3295 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3296 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3297); 3298 3299/* 3300** CAPI3REF: Retrieving Statement SQL 3301** 3302** ^This interface can be used to retrieve a saved copy of the original 3303** SQL text used to create a [prepared statement] if that statement was 3304** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3305*/ 3306SQLITE_API const char *SQLITE_STDCALL sqlite3_sql(sqlite3_stmt *pStmt); 3307 3308/* 3309** CAPI3REF: Determine If An SQL Statement Writes The Database 3310** 3311** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3312** and only if the [prepared statement] X makes no direct changes to 3313** the content of the database file. 3314** 3315** Note that [application-defined SQL functions] or 3316** [virtual tables] might change the database indirectly as a side effect. 3317** ^(For example, if an application defines a function "eval()" that 3318** calls [sqlite3_exec()], then the following SQL statement would 3319** change the database file through side-effects: 3320** 3321** <blockquote><pre> 3322** SELECT eval('DELETE FROM t1') FROM t2; 3323** </pre></blockquote> 3324** 3325** But because the [SELECT] statement does not change the database file 3326** directly, sqlite3_stmt_readonly() would still return true.)^ 3327** 3328** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3329** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3330** since the statements themselves do not actually modify the database but 3331** rather they control the timing of when other statements modify the 3332** database. ^The [ATTACH] and [DETACH] statements also cause 3333** sqlite3_stmt_readonly() to return true since, while those statements 3334** change the configuration of a database connection, they do not make 3335** changes to the content of the database files on disk. 3336*/ 3337SQLITE_API int SQLITE_STDCALL sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3338 3339/* 3340** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3341** 3342** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3343** [prepared statement] S has been stepped at least once using 3344** [sqlite3_step(S)] but has not run to completion and/or has not 3345** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3346** interface returns false if S is a NULL pointer. If S is not a 3347** NULL pointer and is not a pointer to a valid [prepared statement] 3348** object, then the behavior is undefined and probably undesirable. 3349** 3350** This interface can be used in combination [sqlite3_next_stmt()] 3351** to locate all prepared statements associated with a database 3352** connection that are in need of being reset. This can be used, 3353** for example, in diagnostic routines to search for prepared 3354** statements that are holding a transaction open. 3355*/ 3356SQLITE_API int SQLITE_STDCALL sqlite3_stmt_busy(sqlite3_stmt*); 3357 3358/* 3359** CAPI3REF: Dynamically Typed Value Object 3360** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3361** 3362** SQLite uses the sqlite3_value object to represent all values 3363** that can be stored in a database table. SQLite uses dynamic typing 3364** for the values it stores. ^Values stored in sqlite3_value objects 3365** can be integers, floating point values, strings, BLOBs, or NULL. 3366** 3367** An sqlite3_value object may be either "protected" or "unprotected". 3368** Some interfaces require a protected sqlite3_value. Other interfaces 3369** will accept either a protected or an unprotected sqlite3_value. 3370** Every interface that accepts sqlite3_value arguments specifies 3371** whether or not it requires a protected sqlite3_value. 3372** 3373** The terms "protected" and "unprotected" refer to whether or not 3374** a mutex is held. An internal mutex is held for a protected 3375** sqlite3_value object but no mutex is held for an unprotected 3376** sqlite3_value object. If SQLite is compiled to be single-threaded 3377** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3378** or if SQLite is run in one of reduced mutex modes 3379** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3380** then there is no distinction between protected and unprotected 3381** sqlite3_value objects and they can be used interchangeably. However, 3382** for maximum code portability it is recommended that applications 3383** still make the distinction between protected and unprotected 3384** sqlite3_value objects even when not strictly required. 3385** 3386** ^The sqlite3_value objects that are passed as parameters into the 3387** implementation of [application-defined SQL functions] are protected. 3388** ^The sqlite3_value object returned by 3389** [sqlite3_column_value()] is unprotected. 3390** Unprotected sqlite3_value objects may only be used with 3391** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3392** The [sqlite3_value_blob | sqlite3_value_type()] family of 3393** interfaces require protected sqlite3_value objects. 3394*/ 3395typedef struct Mem sqlite3_value; 3396 3397/* 3398** CAPI3REF: SQL Function Context Object 3399** 3400** The context in which an SQL function executes is stored in an 3401** sqlite3_context object. ^A pointer to an sqlite3_context object 3402** is always first parameter to [application-defined SQL functions]. 3403** The application-defined SQL function implementation will pass this 3404** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3405** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3406** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3407** and/or [sqlite3_set_auxdata()]. 3408*/ 3409typedef struct sqlite3_context sqlite3_context; 3410 3411/* 3412** CAPI3REF: Binding Values To Prepared Statements 3413** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3414** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3415** 3416** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3417** literals may be replaced by a [parameter] that matches one of following 3418** templates: 3419** 3420** <ul> 3421** <li> ? 3422** <li> ?NNN 3423** <li> :VVV 3424** <li> @VVV 3425** <li> $VVV 3426** </ul> 3427** 3428** In the templates above, NNN represents an integer literal, 3429** and VVV represents an alphanumeric identifier.)^ ^The values of these 3430** parameters (also called "host parameter names" or "SQL parameters") 3431** can be set using the sqlite3_bind_*() routines defined here. 3432** 3433** ^The first argument to the sqlite3_bind_*() routines is always 3434** a pointer to the [sqlite3_stmt] object returned from 3435** [sqlite3_prepare_v2()] or its variants. 3436** 3437** ^The second argument is the index of the SQL parameter to be set. 3438** ^The leftmost SQL parameter has an index of 1. ^When the same named 3439** SQL parameter is used more than once, second and subsequent 3440** occurrences have the same index as the first occurrence. 3441** ^The index for named parameters can be looked up using the 3442** [sqlite3_bind_parameter_index()] API if desired. ^The index 3443** for "?NNN" parameters is the value of NNN. 3444** ^The NNN value must be between 1 and the [sqlite3_limit()] 3445** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3446** 3447** ^The third argument is the value to bind to the parameter. 3448** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3449** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3450** is ignored and the end result is the same as sqlite3_bind_null(). 3451** 3452** ^(In those routines that have a fourth argument, its value is the 3453** number of bytes in the parameter. To be clear: the value is the 3454** number of <u>bytes</u> in the value, not the number of characters.)^ 3455** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3456** is negative, then the length of the string is 3457** the number of bytes up to the first zero terminator. 3458** If the fourth parameter to sqlite3_bind_blob() is negative, then 3459** the behavior is undefined. 3460** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3461** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3462** that parameter must be the byte offset 3463** where the NUL terminator would occur assuming the string were NUL 3464** terminated. If any NUL characters occur at byte offsets less than 3465** the value of the fourth parameter then the resulting string value will 3466** contain embedded NULs. The result of expressions involving strings 3467** with embedded NULs is undefined. 3468** 3469** ^The fifth argument to the BLOB and string binding interfaces 3470** is a destructor used to dispose of the BLOB or 3471** string after SQLite has finished with it. ^The destructor is called 3472** to dispose of the BLOB or string even if the call to bind API fails. 3473** ^If the fifth argument is 3474** the special value [SQLITE_STATIC], then SQLite assumes that the 3475** information is in static, unmanaged space and does not need to be freed. 3476** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3477** SQLite makes its own private copy of the data immediately, before 3478** the sqlite3_bind_*() routine returns. 3479** 3480** ^The sixth argument to sqlite3_bind_text64() must be one of 3481** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3482** to specify the encoding of the text in the third parameter. If 3483** the sixth argument to sqlite3_bind_text64() is not one of the 3484** allowed values shown above, or if the text encoding is different 3485** from the encoding specified by the sixth parameter, then the behavior 3486** is undefined. 3487** 3488** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3489** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3490** (just an integer to hold its size) while it is being processed. 3491** Zeroblobs are intended to serve as placeholders for BLOBs whose 3492** content is later written using 3493** [sqlite3_blob_open | incremental BLOB I/O] routines. 3494** ^A negative value for the zeroblob results in a zero-length BLOB. 3495** 3496** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3497** for the [prepared statement] or with a prepared statement for which 3498** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3499** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3500** routine is passed a [prepared statement] that has been finalized, the 3501** result is undefined and probably harmful. 3502** 3503** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3504** ^Unbound parameters are interpreted as NULL. 3505** 3506** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3507** [error code] if anything goes wrong. 3508** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3509** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3510** [SQLITE_MAX_LENGTH]. 3511** ^[SQLITE_RANGE] is returned if the parameter 3512** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3513** 3514** See also: [sqlite3_bind_parameter_count()], 3515** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3516*/ 3517SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3518SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3519 void(*)(void*)); 3520SQLITE_API int SQLITE_STDCALL sqlite3_bind_double(sqlite3_stmt*, int, double); 3521SQLITE_API int SQLITE_STDCALL sqlite3_bind_int(sqlite3_stmt*, int, int); 3522SQLITE_API int SQLITE_STDCALL sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3523SQLITE_API int SQLITE_STDCALL sqlite3_bind_null(sqlite3_stmt*, int); 3524SQLITE_API int SQLITE_STDCALL sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3525SQLITE_API int SQLITE_STDCALL sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3526SQLITE_API int SQLITE_STDCALL sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3527 void(*)(void*), unsigned char encoding); 3528SQLITE_API int SQLITE_STDCALL sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3529SQLITE_API int SQLITE_STDCALL sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3530 3531/* 3532** CAPI3REF: Number Of SQL Parameters 3533** 3534** ^This routine can be used to find the number of [SQL parameters] 3535** in a [prepared statement]. SQL parameters are tokens of the 3536** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3537** placeholders for values that are [sqlite3_bind_blob | bound] 3538** to the parameters at a later time. 3539** 3540** ^(This routine actually returns the index of the largest (rightmost) 3541** parameter. For all forms except ?NNN, this will correspond to the 3542** number of unique parameters. If parameters of the ?NNN form are used, 3543** there may be gaps in the list.)^ 3544** 3545** See also: [sqlite3_bind_blob|sqlite3_bind()], 3546** [sqlite3_bind_parameter_name()], and 3547** [sqlite3_bind_parameter_index()]. 3548*/ 3549SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_count(sqlite3_stmt*); 3550 3551/* 3552** CAPI3REF: Name Of A Host Parameter 3553** 3554** ^The sqlite3_bind_parameter_name(P,N) interface returns 3555** the name of the N-th [SQL parameter] in the [prepared statement] P. 3556** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3557** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3558** respectively. 3559** In other words, the initial ":" or "$" or "@" or "?" 3560** is included as part of the name.)^ 3561** ^Parameters of the form "?" without a following integer have no name 3562** and are referred to as "nameless" or "anonymous parameters". 3563** 3564** ^The first host parameter has an index of 1, not 0. 3565** 3566** ^If the value N is out of range or if the N-th parameter is 3567** nameless, then NULL is returned. ^The returned string is 3568** always in UTF-8 encoding even if the named parameter was 3569** originally specified as UTF-16 in [sqlite3_prepare16()] or 3570** [sqlite3_prepare16_v2()]. 3571** 3572** See also: [sqlite3_bind_blob|sqlite3_bind()], 3573** [sqlite3_bind_parameter_count()], and 3574** [sqlite3_bind_parameter_index()]. 3575*/ 3576SQLITE_API const char *SQLITE_STDCALL sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3577 3578/* 3579** CAPI3REF: Index Of A Parameter With A Given Name 3580** 3581** ^Return the index of an SQL parameter given its name. ^The 3582** index value returned is suitable for use as the second 3583** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3584** is returned if no matching parameter is found. ^The parameter 3585** name must be given in UTF-8 even if the original statement 3586** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3587** 3588** See also: [sqlite3_bind_blob|sqlite3_bind()], 3589** [sqlite3_bind_parameter_count()], and 3590** [sqlite3_bind_parameter_index()]. 3591*/ 3592SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3593 3594/* 3595** CAPI3REF: Reset All Bindings On A Prepared Statement 3596** 3597** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3598** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3599** ^Use this routine to reset all host parameters to NULL. 3600*/ 3601SQLITE_API int SQLITE_STDCALL sqlite3_clear_bindings(sqlite3_stmt*); 3602 3603/* 3604** CAPI3REF: Number Of Columns In A Result Set 3605** 3606** ^Return the number of columns in the result set returned by the 3607** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3608** statement that does not return data (for example an [UPDATE]). 3609** 3610** See also: [sqlite3_data_count()] 3611*/ 3612SQLITE_API int SQLITE_STDCALL sqlite3_column_count(sqlite3_stmt *pStmt); 3613 3614/* 3615** CAPI3REF: Column Names In A Result Set 3616** 3617** ^These routines return the name assigned to a particular column 3618** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3619** interface returns a pointer to a zero-terminated UTF-8 string 3620** and sqlite3_column_name16() returns a pointer to a zero-terminated 3621** UTF-16 string. ^The first parameter is the [prepared statement] 3622** that implements the [SELECT] statement. ^The second parameter is the 3623** column number. ^The leftmost column is number 0. 3624** 3625** ^The returned string pointer is valid until either the [prepared statement] 3626** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3627** reprepared by the first call to [sqlite3_step()] for a particular run 3628** or until the next call to 3629** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3630** 3631** ^If sqlite3_malloc() fails during the processing of either routine 3632** (for example during a conversion from UTF-8 to UTF-16) then a 3633** NULL pointer is returned. 3634** 3635** ^The name of a result column is the value of the "AS" clause for 3636** that column, if there is an AS clause. If there is no AS clause 3637** then the name of the column is unspecified and may change from 3638** one release of SQLite to the next. 3639*/ 3640SQLITE_API const char *SQLITE_STDCALL sqlite3_column_name(sqlite3_stmt*, int N); 3641SQLITE_API const void *SQLITE_STDCALL sqlite3_column_name16(sqlite3_stmt*, int N); 3642 3643/* 3644** CAPI3REF: Source Of Data In A Query Result 3645** 3646** ^These routines provide a means to determine the database, table, and 3647** table column that is the origin of a particular result column in 3648** [SELECT] statement. 3649** ^The name of the database or table or column can be returned as 3650** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3651** the database name, the _table_ routines return the table name, and 3652** the origin_ routines return the column name. 3653** ^The returned string is valid until the [prepared statement] is destroyed 3654** using [sqlite3_finalize()] or until the statement is automatically 3655** reprepared by the first call to [sqlite3_step()] for a particular run 3656** or until the same information is requested 3657** again in a different encoding. 3658** 3659** ^The names returned are the original un-aliased names of the 3660** database, table, and column. 3661** 3662** ^The first argument to these interfaces is a [prepared statement]. 3663** ^These functions return information about the Nth result column returned by 3664** the statement, where N is the second function argument. 3665** ^The left-most column is column 0 for these routines. 3666** 3667** ^If the Nth column returned by the statement is an expression or 3668** subquery and is not a column value, then all of these functions return 3669** NULL. ^These routine might also return NULL if a memory allocation error 3670** occurs. ^Otherwise, they return the name of the attached database, table, 3671** or column that query result column was extracted from. 3672** 3673** ^As with all other SQLite APIs, those whose names end with "16" return 3674** UTF-16 encoded strings and the other functions return UTF-8. 3675** 3676** ^These APIs are only available if the library was compiled with the 3677** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3678** 3679** If two or more threads call one or more of these routines against the same 3680** prepared statement and column at the same time then the results are 3681** undefined. 3682** 3683** If two or more threads call one or more 3684** [sqlite3_column_database_name | column metadata interfaces] 3685** for the same [prepared statement] and result column 3686** at the same time then the results are undefined. 3687*/ 3688SQLITE_API const char *SQLITE_STDCALL sqlite3_column_database_name(sqlite3_stmt*,int); 3689SQLITE_API const void *SQLITE_STDCALL sqlite3_column_database_name16(sqlite3_stmt*,int); 3690SQLITE_API const char *SQLITE_STDCALL sqlite3_column_table_name(sqlite3_stmt*,int); 3691SQLITE_API const void *SQLITE_STDCALL sqlite3_column_table_name16(sqlite3_stmt*,int); 3692SQLITE_API const char *SQLITE_STDCALL sqlite3_column_origin_name(sqlite3_stmt*,int); 3693SQLITE_API const void *SQLITE_STDCALL sqlite3_column_origin_name16(sqlite3_stmt*,int); 3694 3695/* 3696** CAPI3REF: Declared Datatype Of A Query Result 3697** 3698** ^(The first parameter is a [prepared statement]. 3699** If this statement is a [SELECT] statement and the Nth column of the 3700** returned result set of that [SELECT] is a table column (not an 3701** expression or subquery) then the declared type of the table 3702** column is returned.)^ ^If the Nth column of the result set is an 3703** expression or subquery, then a NULL pointer is returned. 3704** ^The returned string is always UTF-8 encoded. 3705** 3706** ^(For example, given the database schema: 3707** 3708** CREATE TABLE t1(c1 VARIANT); 3709** 3710** and the following statement to be compiled: 3711** 3712** SELECT c1 + 1, c1 FROM t1; 3713** 3714** this routine would return the string "VARIANT" for the second result 3715** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3716** 3717** ^SQLite uses dynamic run-time typing. ^So just because a column 3718** is declared to contain a particular type does not mean that the 3719** data stored in that column is of the declared type. SQLite is 3720** strongly typed, but the typing is dynamic not static. ^Type 3721** is associated with individual values, not with the containers 3722** used to hold those values. 3723*/ 3724SQLITE_API const char *SQLITE_STDCALL sqlite3_column_decltype(sqlite3_stmt*,int); 3725SQLITE_API const void *SQLITE_STDCALL sqlite3_column_decltype16(sqlite3_stmt*,int); 3726 3727/* 3728** CAPI3REF: Evaluate An SQL Statement 3729** 3730** After a [prepared statement] has been prepared using either 3731** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3732** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3733** must be called one or more times to evaluate the statement. 3734** 3735** The details of the behavior of the sqlite3_step() interface depend 3736** on whether the statement was prepared using the newer "v2" interface 3737** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3738** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3739** new "v2" interface is recommended for new applications but the legacy 3740** interface will continue to be supported. 3741** 3742** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3743** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3744** ^With the "v2" interface, any of the other [result codes] or 3745** [extended result codes] might be returned as well. 3746** 3747** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3748** database locks it needs to do its job. ^If the statement is a [COMMIT] 3749** or occurs outside of an explicit transaction, then you can retry the 3750** statement. If the statement is not a [COMMIT] and occurs within an 3751** explicit transaction then you should rollback the transaction before 3752** continuing. 3753** 3754** ^[SQLITE_DONE] means that the statement has finished executing 3755** successfully. sqlite3_step() should not be called again on this virtual 3756** machine without first calling [sqlite3_reset()] to reset the virtual 3757** machine back to its initial state. 3758** 3759** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3760** is returned each time a new row of data is ready for processing by the 3761** caller. The values may be accessed using the [column access functions]. 3762** sqlite3_step() is called again to retrieve the next row of data. 3763** 3764** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3765** violation) has occurred. sqlite3_step() should not be called again on 3766** the VM. More information may be found by calling [sqlite3_errmsg()]. 3767** ^With the legacy interface, a more specific error code (for example, 3768** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3769** can be obtained by calling [sqlite3_reset()] on the 3770** [prepared statement]. ^In the "v2" interface, 3771** the more specific error code is returned directly by sqlite3_step(). 3772** 3773** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3774** Perhaps it was called on a [prepared statement] that has 3775** already been [sqlite3_finalize | finalized] or on one that had 3776** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3777** be the case that the same database connection is being used by two or 3778** more threads at the same moment in time. 3779** 3780** For all versions of SQLite up to and including 3.6.23.1, a call to 3781** [sqlite3_reset()] was required after sqlite3_step() returned anything 3782** other than [SQLITE_ROW] before any subsequent invocation of 3783** sqlite3_step(). Failure to reset the prepared statement using 3784** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3785** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3786** calling [sqlite3_reset()] automatically in this circumstance rather 3787** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3788** break because any application that ever receives an SQLITE_MISUSE error 3789** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3790** can be used to restore the legacy behavior. 3791** 3792** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3793** API always returns a generic error code, [SQLITE_ERROR], following any 3794** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3795** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3796** specific [error codes] that better describes the error. 3797** We admit that this is a goofy design. The problem has been fixed 3798** with the "v2" interface. If you prepare all of your SQL statements 3799** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3800** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3801** then the more specific [error codes] are returned directly 3802** by sqlite3_step(). The use of the "v2" interface is recommended. 3803*/ 3804SQLITE_API int SQLITE_STDCALL sqlite3_step(sqlite3_stmt*); 3805 3806/* 3807** CAPI3REF: Number of columns in a result set 3808** 3809** ^The sqlite3_data_count(P) interface returns the number of columns in the 3810** current row of the result set of [prepared statement] P. 3811** ^If prepared statement P does not have results ready to return 3812** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3813** interfaces) then sqlite3_data_count(P) returns 0. 3814** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3815** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3816** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3817** will return non-zero if previous call to [sqlite3_step](P) returned 3818** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3819** where it always returns zero since each step of that multi-step 3820** pragma returns 0 columns of data. 3821** 3822** See also: [sqlite3_column_count()] 3823*/ 3824SQLITE_API int SQLITE_STDCALL sqlite3_data_count(sqlite3_stmt *pStmt); 3825 3826/* 3827** CAPI3REF: Fundamental Datatypes 3828** KEYWORDS: SQLITE_TEXT 3829** 3830** ^(Every value in SQLite has one of five fundamental datatypes: 3831** 3832** <ul> 3833** <li> 64-bit signed integer 3834** <li> 64-bit IEEE floating point number 3835** <li> string 3836** <li> BLOB 3837** <li> NULL 3838** </ul>)^ 3839** 3840** These constants are codes for each of those types. 3841** 3842** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3843** for a completely different meaning. Software that links against both 3844** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3845** SQLITE_TEXT. 3846*/ 3847#define SQLITE_INTEGER 1 3848#define SQLITE_FLOAT 2 3849#define SQLITE_BLOB 4 3850#define SQLITE_NULL 5 3851#ifdef SQLITE_TEXT 3852# undef SQLITE_TEXT 3853#else 3854# define SQLITE_TEXT 3 3855#endif 3856#define SQLITE3_TEXT 3 3857 3858/* 3859** CAPI3REF: Result Values From A Query 3860** KEYWORDS: {column access functions} 3861** 3862** These routines form the "result set" interface. 3863** 3864** ^These routines return information about a single column of the current 3865** result row of a query. ^In every case the first argument is a pointer 3866** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3867** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3868** and the second argument is the index of the column for which information 3869** should be returned. ^The leftmost column of the result set has the index 0. 3870** ^The number of columns in the result can be determined using 3871** [sqlite3_column_count()]. 3872** 3873** If the SQL statement does not currently point to a valid row, or if the 3874** column index is out of range, the result is undefined. 3875** These routines may only be called when the most recent call to 3876** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3877** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3878** If any of these routines are called after [sqlite3_reset()] or 3879** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3880** something other than [SQLITE_ROW], the results are undefined. 3881** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3882** are called from a different thread while any of these routines 3883** are pending, then the results are undefined. 3884** 3885** ^The sqlite3_column_type() routine returns the 3886** [SQLITE_INTEGER | datatype code] for the initial data type 3887** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3888** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3889** returned by sqlite3_column_type() is only meaningful if no type 3890** conversions have occurred as described below. After a type conversion, 3891** the value returned by sqlite3_column_type() is undefined. Future 3892** versions of SQLite may change the behavior of sqlite3_column_type() 3893** following a type conversion. 3894** 3895** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3896** routine returns the number of bytes in that BLOB or string. 3897** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3898** the string to UTF-8 and then returns the number of bytes. 3899** ^If the result is a numeric value then sqlite3_column_bytes() uses 3900** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3901** the number of bytes in that string. 3902** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3903** 3904** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3905** routine returns the number of bytes in that BLOB or string. 3906** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3907** the string to UTF-16 and then returns the number of bytes. 3908** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3909** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3910** the number of bytes in that string. 3911** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3912** 3913** ^The values returned by [sqlite3_column_bytes()] and 3914** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3915** of the string. ^For clarity: the values returned by 3916** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3917** bytes in the string, not the number of characters. 3918** 3919** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3920** even empty strings, are always zero-terminated. ^The return 3921** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3922** 3923** ^The object returned by [sqlite3_column_value()] is an 3924** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3925** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3926** If the [unprotected sqlite3_value] object returned by 3927** [sqlite3_column_value()] is used in any other way, including calls 3928** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3929** or [sqlite3_value_bytes()], then the behavior is undefined. 3930** 3931** These routines attempt to convert the value where appropriate. ^For 3932** example, if the internal representation is FLOAT and a text result 3933** is requested, [sqlite3_snprintf()] is used internally to perform the 3934** conversion automatically. ^(The following table details the conversions 3935** that are applied: 3936** 3937** <blockquote> 3938** <table border="1"> 3939** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3940** 3941** <tr><td> NULL <td> INTEGER <td> Result is 0 3942** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3943** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 3944** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 3945** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3946** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3947** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3948** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 3949** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3950** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 3951** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 3952** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 3953** <tr><td> TEXT <td> BLOB <td> No change 3954** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 3955** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 3956** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3957** </table> 3958** </blockquote>)^ 3959** 3960** The table above makes reference to standard C library functions atoi() 3961** and atof(). SQLite does not really use these functions. It has its 3962** own equivalent internal routines. The atoi() and atof() names are 3963** used in the table for brevity and because they are familiar to most 3964** C programmers. 3965** 3966** Note that when type conversions occur, pointers returned by prior 3967** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3968** sqlite3_column_text16() may be invalidated. 3969** Type conversions and pointer invalidations might occur 3970** in the following cases: 3971** 3972** <ul> 3973** <li> The initial content is a BLOB and sqlite3_column_text() or 3974** sqlite3_column_text16() is called. A zero-terminator might 3975** need to be added to the string.</li> 3976** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3977** sqlite3_column_text16() is called. The content must be converted 3978** to UTF-16.</li> 3979** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3980** sqlite3_column_text() is called. The content must be converted 3981** to UTF-8.</li> 3982** </ul> 3983** 3984** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3985** not invalidate a prior pointer, though of course the content of the buffer 3986** that the prior pointer references will have been modified. Other kinds 3987** of conversion are done in place when it is possible, but sometimes they 3988** are not possible and in those cases prior pointers are invalidated. 3989** 3990** The safest and easiest to remember policy is to invoke these routines 3991** in one of the following ways: 3992** 3993** <ul> 3994** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3995** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3996** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3997** </ul> 3998** 3999** In other words, you should call sqlite3_column_text(), 4000** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4001** into the desired format, then invoke sqlite3_column_bytes() or 4002** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4003** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4004** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4005** with calls to sqlite3_column_bytes(). 4006** 4007** ^The pointers returned are valid until a type conversion occurs as 4008** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4009** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4010** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 4011** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4012** [sqlite3_free()]. 4013** 4014** ^(If a memory allocation error occurs during the evaluation of any 4015** of these routines, a default value is returned. The default value 4016** is either the integer 0, the floating point number 0.0, or a NULL 4017** pointer. Subsequent calls to [sqlite3_errcode()] will return 4018** [SQLITE_NOMEM].)^ 4019*/ 4020SQLITE_API const void *SQLITE_STDCALL sqlite3_column_blob(sqlite3_stmt*, int iCol); 4021SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4022SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4023SQLITE_API double SQLITE_STDCALL sqlite3_column_double(sqlite3_stmt*, int iCol); 4024SQLITE_API int SQLITE_STDCALL sqlite3_column_int(sqlite3_stmt*, int iCol); 4025SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_column_int64(sqlite3_stmt*, int iCol); 4026SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_column_text(sqlite3_stmt*, int iCol); 4027SQLITE_API const void *SQLITE_STDCALL sqlite3_column_text16(sqlite3_stmt*, int iCol); 4028SQLITE_API int SQLITE_STDCALL sqlite3_column_type(sqlite3_stmt*, int iCol); 4029SQLITE_API sqlite3_value *SQLITE_STDCALL sqlite3_column_value(sqlite3_stmt*, int iCol); 4030 4031/* 4032** CAPI3REF: Destroy A Prepared Statement Object 4033** 4034** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4035** ^If the most recent evaluation of the statement encountered no errors 4036** or if the statement is never been evaluated, then sqlite3_finalize() returns 4037** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4038** sqlite3_finalize(S) returns the appropriate [error code] or 4039** [extended error code]. 4040** 4041** ^The sqlite3_finalize(S) routine can be called at any point during 4042** the life cycle of [prepared statement] S: 4043** before statement S is ever evaluated, after 4044** one or more calls to [sqlite3_reset()], or after any call 4045** to [sqlite3_step()] regardless of whether or not the statement has 4046** completed execution. 4047** 4048** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4049** 4050** The application must finalize every [prepared statement] in order to avoid 4051** resource leaks. It is a grievous error for the application to try to use 4052** a prepared statement after it has been finalized. Any use of a prepared 4053** statement after it has been finalized can result in undefined and 4054** undesirable behavior such as segfaults and heap corruption. 4055*/ 4056SQLITE_API int SQLITE_STDCALL sqlite3_finalize(sqlite3_stmt *pStmt); 4057 4058/* 4059** CAPI3REF: Reset A Prepared Statement Object 4060** 4061** The sqlite3_reset() function is called to reset a [prepared statement] 4062** object back to its initial state, ready to be re-executed. 4063** ^Any SQL statement variables that had values bound to them using 4064** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4065** Use [sqlite3_clear_bindings()] to reset the bindings. 4066** 4067** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4068** back to the beginning of its program. 4069** 4070** ^If the most recent call to [sqlite3_step(S)] for the 4071** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4072** or if [sqlite3_step(S)] has never before been called on S, 4073** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4074** 4075** ^If the most recent call to [sqlite3_step(S)] for the 4076** [prepared statement] S indicated an error, then 4077** [sqlite3_reset(S)] returns an appropriate [error code]. 4078** 4079** ^The [sqlite3_reset(S)] interface does not change the values 4080** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4081*/ 4082SQLITE_API int SQLITE_STDCALL sqlite3_reset(sqlite3_stmt *pStmt); 4083 4084/* 4085** CAPI3REF: Create Or Redefine SQL Functions 4086** KEYWORDS: {function creation routines} 4087** KEYWORDS: {application-defined SQL function} 4088** KEYWORDS: {application-defined SQL functions} 4089** 4090** ^These functions (collectively known as "function creation routines") 4091** are used to add SQL functions or aggregates or to redefine the behavior 4092** of existing SQL functions or aggregates. The only differences between 4093** these routines are the text encoding expected for 4094** the second parameter (the name of the function being created) 4095** and the presence or absence of a destructor callback for 4096** the application data pointer. 4097** 4098** ^The first parameter is the [database connection] to which the SQL 4099** function is to be added. ^If an application uses more than one database 4100** connection then application-defined SQL functions must be added 4101** to each database connection separately. 4102** 4103** ^The second parameter is the name of the SQL function to be created or 4104** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4105** representation, exclusive of the zero-terminator. ^Note that the name 4106** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4107** ^Any attempt to create a function with a longer name 4108** will result in [SQLITE_MISUSE] being returned. 4109** 4110** ^The third parameter (nArg) 4111** is the number of arguments that the SQL function or 4112** aggregate takes. ^If this parameter is -1, then the SQL function or 4113** aggregate may take any number of arguments between 0 and the limit 4114** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4115** parameter is less than -1 or greater than 127 then the behavior is 4116** undefined. 4117** 4118** ^The fourth parameter, eTextRep, specifies what 4119** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4120** its parameters. The application should set this parameter to 4121** [SQLITE_UTF16LE] if the function implementation invokes 4122** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4123** implementation invokes [sqlite3_value_text16be()] on an input, or 4124** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4125** otherwise. ^The same SQL function may be registered multiple times using 4126** different preferred text encodings, with different implementations for 4127** each encoding. 4128** ^When multiple implementations of the same function are available, SQLite 4129** will pick the one that involves the least amount of data conversion. 4130** 4131** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4132** to signal that the function will always return the same result given 4133** the same inputs within a single SQL statement. Most SQL functions are 4134** deterministic. The built-in [random()] SQL function is an example of a 4135** function that is not deterministic. The SQLite query planner is able to 4136** perform additional optimizations on deterministic functions, so use 4137** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4138** 4139** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4140** function can gain access to this pointer using [sqlite3_user_data()].)^ 4141** 4142** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4143** pointers to C-language functions that implement the SQL function or 4144** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4145** callback only; NULL pointers must be passed as the xStep and xFinal 4146** parameters. ^An aggregate SQL function requires an implementation of xStep 4147** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4148** SQL function or aggregate, pass NULL pointers for all three function 4149** callbacks. 4150** 4151** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4152** then it is destructor for the application data pointer. 4153** The destructor is invoked when the function is deleted, either by being 4154** overloaded or when the database connection closes.)^ 4155** ^The destructor is also invoked if the call to 4156** sqlite3_create_function_v2() fails. 4157** ^When the destructor callback of the tenth parameter is invoked, it 4158** is passed a single argument which is a copy of the application data 4159** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4160** 4161** ^It is permitted to register multiple implementations of the same 4162** functions with the same name but with either differing numbers of 4163** arguments or differing preferred text encodings. ^SQLite will use 4164** the implementation that most closely matches the way in which the 4165** SQL function is used. ^A function implementation with a non-negative 4166** nArg parameter is a better match than a function implementation with 4167** a negative nArg. ^A function where the preferred text encoding 4168** matches the database encoding is a better 4169** match than a function where the encoding is different. 4170** ^A function where the encoding difference is between UTF16le and UTF16be 4171** is a closer match than a function where the encoding difference is 4172** between UTF8 and UTF16. 4173** 4174** ^Built-in functions may be overloaded by new application-defined functions. 4175** 4176** ^An application-defined function is permitted to call other 4177** SQLite interfaces. However, such calls must not 4178** close the database connection nor finalize or reset the prepared 4179** statement in which the function is running. 4180*/ 4181SQLITE_API int SQLITE_STDCALL sqlite3_create_function( 4182 sqlite3 *db, 4183 const char *zFunctionName, 4184 int nArg, 4185 int eTextRep, 4186 void *pApp, 4187 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4188 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4189 void (*xFinal)(sqlite3_context*) 4190); 4191SQLITE_API int SQLITE_STDCALL sqlite3_create_function16( 4192 sqlite3 *db, 4193 const void *zFunctionName, 4194 int nArg, 4195 int eTextRep, 4196 void *pApp, 4197 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4198 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4199 void (*xFinal)(sqlite3_context*) 4200); 4201SQLITE_API int SQLITE_STDCALL sqlite3_create_function_v2( 4202 sqlite3 *db, 4203 const char *zFunctionName, 4204 int nArg, 4205 int eTextRep, 4206 void *pApp, 4207 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4208 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4209 void (*xFinal)(sqlite3_context*), 4210 void(*xDestroy)(void*) 4211); 4212 4213/* 4214** CAPI3REF: Text Encodings 4215** 4216** These constant define integer codes that represent the various 4217** text encodings supported by SQLite. 4218*/ 4219#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4220#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4221#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4222#define SQLITE_UTF16 4 /* Use native byte order */ 4223#define SQLITE_ANY 5 /* Deprecated */ 4224#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4225 4226/* 4227** CAPI3REF: Function Flags 4228** 4229** These constants may be ORed together with the 4230** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4231** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4232** [sqlite3_create_function_v2()]. 4233*/ 4234#define SQLITE_DETERMINISTIC 0x800 4235 4236/* 4237** CAPI3REF: Deprecated Functions 4238** DEPRECATED 4239** 4240** These functions are [deprecated]. In order to maintain 4241** backwards compatibility with older code, these functions continue 4242** to be supported. However, new applications should avoid 4243** the use of these functions. To encourage programmers to avoid 4244** these functions, we will not explain what they do. 4245*/ 4246#ifndef SQLITE_OMIT_DEPRECATED 4247SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_aggregate_count(sqlite3_context*); 4248SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_expired(sqlite3_stmt*); 4249SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4250SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_global_recover(void); 4251SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_thread_cleanup(void); 4252SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4253 void*,sqlite3_int64); 4254#endif 4255 4256/* 4257** CAPI3REF: Obtaining SQL Function Parameter Values 4258** 4259** The C-language implementation of SQL functions and aggregates uses 4260** this set of interface routines to access the parameter values on 4261** the function or aggregate. 4262** 4263** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4264** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4265** define callbacks that implement the SQL functions and aggregates. 4266** The 3rd parameter to these callbacks is an array of pointers to 4267** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4268** each parameter to the SQL function. These routines are used to 4269** extract values from the [sqlite3_value] objects. 4270** 4271** These routines work only with [protected sqlite3_value] objects. 4272** Any attempt to use these routines on an [unprotected sqlite3_value] 4273** object results in undefined behavior. 4274** 4275** ^These routines work just like the corresponding [column access functions] 4276** except that these routines take a single [protected sqlite3_value] object 4277** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4278** 4279** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4280** in the native byte-order of the host machine. ^The 4281** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4282** extract UTF-16 strings as big-endian and little-endian respectively. 4283** 4284** ^(The sqlite3_value_numeric_type() interface attempts to apply 4285** numeric affinity to the value. This means that an attempt is 4286** made to convert the value to an integer or floating point. If 4287** such a conversion is possible without loss of information (in other 4288** words, if the value is a string that looks like a number) 4289** then the conversion is performed. Otherwise no conversion occurs. 4290** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4291** 4292** Please pay particular attention to the fact that the pointer returned 4293** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4294** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4295** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4296** or [sqlite3_value_text16()]. 4297** 4298** These routines must be called from the same thread as 4299** the SQL function that supplied the [sqlite3_value*] parameters. 4300*/ 4301SQLITE_API const void *SQLITE_STDCALL sqlite3_value_blob(sqlite3_value*); 4302SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes(sqlite3_value*); 4303SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes16(sqlite3_value*); 4304SQLITE_API double SQLITE_STDCALL sqlite3_value_double(sqlite3_value*); 4305SQLITE_API int SQLITE_STDCALL sqlite3_value_int(sqlite3_value*); 4306SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_value_int64(sqlite3_value*); 4307SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_value_text(sqlite3_value*); 4308SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16(sqlite3_value*); 4309SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16le(sqlite3_value*); 4310SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16be(sqlite3_value*); 4311SQLITE_API int SQLITE_STDCALL sqlite3_value_type(sqlite3_value*); 4312SQLITE_API int SQLITE_STDCALL sqlite3_value_numeric_type(sqlite3_value*); 4313 4314/* 4315** CAPI3REF: Obtain Aggregate Function Context 4316** 4317** Implementations of aggregate SQL functions use this 4318** routine to allocate memory for storing their state. 4319** 4320** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4321** for a particular aggregate function, SQLite 4322** allocates N of memory, zeroes out that memory, and returns a pointer 4323** to the new memory. ^On second and subsequent calls to 4324** sqlite3_aggregate_context() for the same aggregate function instance, 4325** the same buffer is returned. Sqlite3_aggregate_context() is normally 4326** called once for each invocation of the xStep callback and then one 4327** last time when the xFinal callback is invoked. ^(When no rows match 4328** an aggregate query, the xStep() callback of the aggregate function 4329** implementation is never called and xFinal() is called exactly once. 4330** In those cases, sqlite3_aggregate_context() might be called for the 4331** first time from within xFinal().)^ 4332** 4333** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4334** when first called if N is less than or equal to zero or if a memory 4335** allocate error occurs. 4336** 4337** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4338** determined by the N parameter on first successful call. Changing the 4339** value of N in subsequent call to sqlite3_aggregate_context() within 4340** the same aggregate function instance will not resize the memory 4341** allocation.)^ Within the xFinal callback, it is customary to set 4342** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4343** pointless memory allocations occur. 4344** 4345** ^SQLite automatically frees the memory allocated by 4346** sqlite3_aggregate_context() when the aggregate query concludes. 4347** 4348** The first parameter must be a copy of the 4349** [sqlite3_context | SQL function context] that is the first parameter 4350** to the xStep or xFinal callback routine that implements the aggregate 4351** function. 4352** 4353** This routine must be called from the same thread in which 4354** the aggregate SQL function is running. 4355*/ 4356SQLITE_API void *SQLITE_STDCALL sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4357 4358/* 4359** CAPI3REF: User Data For Functions 4360** 4361** ^The sqlite3_user_data() interface returns a copy of 4362** the pointer that was the pUserData parameter (the 5th parameter) 4363** of the [sqlite3_create_function()] 4364** and [sqlite3_create_function16()] routines that originally 4365** registered the application defined function. 4366** 4367** This routine must be called from the same thread in which 4368** the application-defined function is running. 4369*/ 4370SQLITE_API void *SQLITE_STDCALL sqlite3_user_data(sqlite3_context*); 4371 4372/* 4373** CAPI3REF: Database Connection For Functions 4374** 4375** ^The sqlite3_context_db_handle() interface returns a copy of 4376** the pointer to the [database connection] (the 1st parameter) 4377** of the [sqlite3_create_function()] 4378** and [sqlite3_create_function16()] routines that originally 4379** registered the application defined function. 4380*/ 4381SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_context_db_handle(sqlite3_context*); 4382 4383/* 4384** CAPI3REF: Function Auxiliary Data 4385** 4386** These functions may be used by (non-aggregate) SQL functions to 4387** associate metadata with argument values. If the same value is passed to 4388** multiple invocations of the same SQL function during query execution, under 4389** some circumstances the associated metadata may be preserved. An example 4390** of where this might be useful is in a regular-expression matching 4391** function. The compiled version of the regular expression can be stored as 4392** metadata associated with the pattern string. 4393** Then as long as the pattern string remains the same, 4394** the compiled regular expression can be reused on multiple 4395** invocations of the same function. 4396** 4397** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4398** associated by the sqlite3_set_auxdata() function with the Nth argument 4399** value to the application-defined function. ^If there is no metadata 4400** associated with the function argument, this sqlite3_get_auxdata() interface 4401** returns a NULL pointer. 4402** 4403** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4404** argument of the application-defined function. ^Subsequent 4405** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4406** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4407** NULL if the metadata has been discarded. 4408** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4409** SQLite will invoke the destructor function X with parameter P exactly 4410** once, when the metadata is discarded. 4411** SQLite is free to discard the metadata at any time, including: <ul> 4412** <li> when the corresponding function parameter changes, or 4413** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4414** SQL statement, or 4415** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or 4416** <li> during the original sqlite3_set_auxdata() call when a memory 4417** allocation error occurs. </ul>)^ 4418** 4419** Note the last bullet in particular. The destructor X in 4420** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4421** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4422** should be called near the end of the function implementation and the 4423** function implementation should not make any use of P after 4424** sqlite3_set_auxdata() has been called. 4425** 4426** ^(In practice, metadata is preserved between function calls for 4427** function parameters that are compile-time constants, including literal 4428** values and [parameters] and expressions composed from the same.)^ 4429** 4430** These routines must be called from the same thread in which 4431** the SQL function is running. 4432*/ 4433SQLITE_API void *SQLITE_STDCALL sqlite3_get_auxdata(sqlite3_context*, int N); 4434SQLITE_API void SQLITE_STDCALL sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4435 4436 4437/* 4438** CAPI3REF: Constants Defining Special Destructor Behavior 4439** 4440** These are special values for the destructor that is passed in as the 4441** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4442** argument is SQLITE_STATIC, it means that the content pointer is constant 4443** and will never change. It does not need to be destroyed. ^The 4444** SQLITE_TRANSIENT value means that the content will likely change in 4445** the near future and that SQLite should make its own private copy of 4446** the content before returning. 4447** 4448** The typedef is necessary to work around problems in certain 4449** C++ compilers. 4450*/ 4451typedef void (*sqlite3_destructor_type)(void*); 4452#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4453#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4454 4455/* 4456** CAPI3REF: Setting The Result Of An SQL Function 4457** 4458** These routines are used by the xFunc or xFinal callbacks that 4459** implement SQL functions and aggregates. See 4460** [sqlite3_create_function()] and [sqlite3_create_function16()] 4461** for additional information. 4462** 4463** These functions work very much like the [parameter binding] family of 4464** functions used to bind values to host parameters in prepared statements. 4465** Refer to the [SQL parameter] documentation for additional information. 4466** 4467** ^The sqlite3_result_blob() interface sets the result from 4468** an application-defined function to be the BLOB whose content is pointed 4469** to by the second parameter and which is N bytes long where N is the 4470** third parameter. 4471** 4472** ^The sqlite3_result_zeroblob() interfaces set the result of 4473** the application-defined function to be a BLOB containing all zero 4474** bytes and N bytes in size, where N is the value of the 2nd parameter. 4475** 4476** ^The sqlite3_result_double() interface sets the result from 4477** an application-defined function to be a floating point value specified 4478** by its 2nd argument. 4479** 4480** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4481** cause the implemented SQL function to throw an exception. 4482** ^SQLite uses the string pointed to by the 4483** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4484** as the text of an error message. ^SQLite interprets the error 4485** message string from sqlite3_result_error() as UTF-8. ^SQLite 4486** interprets the string from sqlite3_result_error16() as UTF-16 in native 4487** byte order. ^If the third parameter to sqlite3_result_error() 4488** or sqlite3_result_error16() is negative then SQLite takes as the error 4489** message all text up through the first zero character. 4490** ^If the third parameter to sqlite3_result_error() or 4491** sqlite3_result_error16() is non-negative then SQLite takes that many 4492** bytes (not characters) from the 2nd parameter as the error message. 4493** ^The sqlite3_result_error() and sqlite3_result_error16() 4494** routines make a private copy of the error message text before 4495** they return. Hence, the calling function can deallocate or 4496** modify the text after they return without harm. 4497** ^The sqlite3_result_error_code() function changes the error code 4498** returned by SQLite as a result of an error in a function. ^By default, 4499** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4500** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4501** 4502** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4503** error indicating that a string or BLOB is too long to represent. 4504** 4505** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4506** error indicating that a memory allocation failed. 4507** 4508** ^The sqlite3_result_int() interface sets the return value 4509** of the application-defined function to be the 32-bit signed integer 4510** value given in the 2nd argument. 4511** ^The sqlite3_result_int64() interface sets the return value 4512** of the application-defined function to be the 64-bit signed integer 4513** value given in the 2nd argument. 4514** 4515** ^The sqlite3_result_null() interface sets the return value 4516** of the application-defined function to be NULL. 4517** 4518** ^The sqlite3_result_text(), sqlite3_result_text16(), 4519** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4520** set the return value of the application-defined function to be 4521** a text string which is represented as UTF-8, UTF-16 native byte order, 4522** UTF-16 little endian, or UTF-16 big endian, respectively. 4523** ^The sqlite3_result_text64() interface sets the return value of an 4524** application-defined function to be a text string in an encoding 4525** specified by the fifth (and last) parameter, which must be one 4526** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 4527** ^SQLite takes the text result from the application from 4528** the 2nd parameter of the sqlite3_result_text* interfaces. 4529** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4530** is negative, then SQLite takes result text from the 2nd parameter 4531** through the first zero character. 4532** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4533** is non-negative, then as many bytes (not characters) of the text 4534** pointed to by the 2nd parameter are taken as the application-defined 4535** function result. If the 3rd parameter is non-negative, then it 4536** must be the byte offset into the string where the NUL terminator would 4537** appear if the string where NUL terminated. If any NUL characters occur 4538** in the string at a byte offset that is less than the value of the 3rd 4539** parameter, then the resulting string will contain embedded NULs and the 4540** result of expressions operating on strings with embedded NULs is undefined. 4541** ^If the 4th parameter to the sqlite3_result_text* interfaces 4542** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4543** function as the destructor on the text or BLOB result when it has 4544** finished using that result. 4545** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4546** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4547** assumes that the text or BLOB result is in constant space and does not 4548** copy the content of the parameter nor call a destructor on the content 4549** when it has finished using that result. 4550** ^If the 4th parameter to the sqlite3_result_text* interfaces 4551** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4552** then SQLite makes a copy of the result into space obtained from 4553** from [sqlite3_malloc()] before it returns. 4554** 4555** ^The sqlite3_result_value() interface sets the result of 4556** the application-defined function to be a copy the 4557** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4558** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4559** so that the [sqlite3_value] specified in the parameter may change or 4560** be deallocated after sqlite3_result_value() returns without harm. 4561** ^A [protected sqlite3_value] object may always be used where an 4562** [unprotected sqlite3_value] object is required, so either 4563** kind of [sqlite3_value] object can be used with this interface. 4564** 4565** If these routines are called from within the different thread 4566** than the one containing the application-defined function that received 4567** the [sqlite3_context] pointer, the results are undefined. 4568*/ 4569SQLITE_API void SQLITE_STDCALL sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4570SQLITE_API void SQLITE_STDCALL sqlite3_result_blob64(sqlite3_context*,const void*, 4571 sqlite3_uint64,void(*)(void*)); 4572SQLITE_API void SQLITE_STDCALL sqlite3_result_double(sqlite3_context*, double); 4573SQLITE_API void SQLITE_STDCALL sqlite3_result_error(sqlite3_context*, const char*, int); 4574SQLITE_API void SQLITE_STDCALL sqlite3_result_error16(sqlite3_context*, const void*, int); 4575SQLITE_API void SQLITE_STDCALL sqlite3_result_error_toobig(sqlite3_context*); 4576SQLITE_API void SQLITE_STDCALL sqlite3_result_error_nomem(sqlite3_context*); 4577SQLITE_API void SQLITE_STDCALL sqlite3_result_error_code(sqlite3_context*, int); 4578SQLITE_API void SQLITE_STDCALL sqlite3_result_int(sqlite3_context*, int); 4579SQLITE_API void SQLITE_STDCALL sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4580SQLITE_API void SQLITE_STDCALL sqlite3_result_null(sqlite3_context*); 4581SQLITE_API void SQLITE_STDCALL sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4582SQLITE_API void SQLITE_STDCALL sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 4583 void(*)(void*), unsigned char encoding); 4584SQLITE_API void SQLITE_STDCALL sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4585SQLITE_API void SQLITE_STDCALL sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4586SQLITE_API void SQLITE_STDCALL sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4587SQLITE_API void SQLITE_STDCALL sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4588SQLITE_API void SQLITE_STDCALL sqlite3_result_zeroblob(sqlite3_context*, int n); 4589 4590/* 4591** CAPI3REF: Define New Collating Sequences 4592** 4593** ^These functions add, remove, or modify a [collation] associated 4594** with the [database connection] specified as the first argument. 4595** 4596** ^The name of the collation is a UTF-8 string 4597** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4598** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4599** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4600** considered to be the same name. 4601** 4602** ^(The third argument (eTextRep) must be one of the constants: 4603** <ul> 4604** <li> [SQLITE_UTF8], 4605** <li> [SQLITE_UTF16LE], 4606** <li> [SQLITE_UTF16BE], 4607** <li> [SQLITE_UTF16], or 4608** <li> [SQLITE_UTF16_ALIGNED]. 4609** </ul>)^ 4610** ^The eTextRep argument determines the encoding of strings passed 4611** to the collating function callback, xCallback. 4612** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4613** force strings to be UTF16 with native byte order. 4614** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4615** on an even byte address. 4616** 4617** ^The fourth argument, pArg, is an application data pointer that is passed 4618** through as the first argument to the collating function callback. 4619** 4620** ^The fifth argument, xCallback, is a pointer to the collating function. 4621** ^Multiple collating functions can be registered using the same name but 4622** with different eTextRep parameters and SQLite will use whichever 4623** function requires the least amount of data transformation. 4624** ^If the xCallback argument is NULL then the collating function is 4625** deleted. ^When all collating functions having the same name are deleted, 4626** that collation is no longer usable. 4627** 4628** ^The collating function callback is invoked with a copy of the pArg 4629** application data pointer and with two strings in the encoding specified 4630** by the eTextRep argument. The collating function must return an 4631** integer that is negative, zero, or positive 4632** if the first string is less than, equal to, or greater than the second, 4633** respectively. A collating function must always return the same answer 4634** given the same inputs. If two or more collating functions are registered 4635** to the same collation name (using different eTextRep values) then all 4636** must give an equivalent answer when invoked with equivalent strings. 4637** The collating function must obey the following properties for all 4638** strings A, B, and C: 4639** 4640** <ol> 4641** <li> If A==B then B==A. 4642** <li> If A==B and B==C then A==C. 4643** <li> If A<B THEN B>A. 4644** <li> If A<B and B<C then A<C. 4645** </ol> 4646** 4647** If a collating function fails any of the above constraints and that 4648** collating function is registered and used, then the behavior of SQLite 4649** is undefined. 4650** 4651** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4652** with the addition that the xDestroy callback is invoked on pArg when 4653** the collating function is deleted. 4654** ^Collating functions are deleted when they are overridden by later 4655** calls to the collation creation functions or when the 4656** [database connection] is closed using [sqlite3_close()]. 4657** 4658** ^The xDestroy callback is <u>not</u> called if the 4659** sqlite3_create_collation_v2() function fails. Applications that invoke 4660** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4661** check the return code and dispose of the application data pointer 4662** themselves rather than expecting SQLite to deal with it for them. 4663** This is different from every other SQLite interface. The inconsistency 4664** is unfortunate but cannot be changed without breaking backwards 4665** compatibility. 4666** 4667** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4668*/ 4669SQLITE_API int SQLITE_STDCALL sqlite3_create_collation( 4670 sqlite3*, 4671 const char *zName, 4672 int eTextRep, 4673 void *pArg, 4674 int(*xCompare)(void*,int,const void*,int,const void*) 4675); 4676SQLITE_API int SQLITE_STDCALL sqlite3_create_collation_v2( 4677 sqlite3*, 4678 const char *zName, 4679 int eTextRep, 4680 void *pArg, 4681 int(*xCompare)(void*,int,const void*,int,const void*), 4682 void(*xDestroy)(void*) 4683); 4684SQLITE_API int SQLITE_STDCALL sqlite3_create_collation16( 4685 sqlite3*, 4686 const void *zName, 4687 int eTextRep, 4688 void *pArg, 4689 int(*xCompare)(void*,int,const void*,int,const void*) 4690); 4691 4692/* 4693** CAPI3REF: Collation Needed Callbacks 4694** 4695** ^To avoid having to register all collation sequences before a database 4696** can be used, a single callback function may be registered with the 4697** [database connection] to be invoked whenever an undefined collation 4698** sequence is required. 4699** 4700** ^If the function is registered using the sqlite3_collation_needed() API, 4701** then it is passed the names of undefined collation sequences as strings 4702** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4703** the names are passed as UTF-16 in machine native byte order. 4704** ^A call to either function replaces the existing collation-needed callback. 4705** 4706** ^(When the callback is invoked, the first argument passed is a copy 4707** of the second argument to sqlite3_collation_needed() or 4708** sqlite3_collation_needed16(). The second argument is the database 4709** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4710** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4711** sequence function required. The fourth parameter is the name of the 4712** required collation sequence.)^ 4713** 4714** The callback function should register the desired collation using 4715** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4716** [sqlite3_create_collation_v2()]. 4717*/ 4718SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed( 4719 sqlite3*, 4720 void*, 4721 void(*)(void*,sqlite3*,int eTextRep,const char*) 4722); 4723SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed16( 4724 sqlite3*, 4725 void*, 4726 void(*)(void*,sqlite3*,int eTextRep,const void*) 4727); 4728 4729#ifdef SQLITE_HAS_CODEC 4730/* 4731** Specify the key for an encrypted database. This routine should be 4732** called right after sqlite3_open(). 4733** 4734** The code to implement this API is not available in the public release 4735** of SQLite. 4736*/ 4737SQLITE_API int SQLITE_STDCALL sqlite3_key( 4738 sqlite3 *db, /* Database to be rekeyed */ 4739 const void *pKey, int nKey /* The key */ 4740); 4741SQLITE_API int SQLITE_STDCALL sqlite3_key_v2( 4742 sqlite3 *db, /* Database to be rekeyed */ 4743 const char *zDbName, /* Name of the database */ 4744 const void *pKey, int nKey /* The key */ 4745); 4746 4747/* 4748** Change the key on an open database. If the current database is not 4749** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4750** database is decrypted. 4751** 4752** The code to implement this API is not available in the public release 4753** of SQLite. 4754*/ 4755SQLITE_API int SQLITE_STDCALL sqlite3_rekey( 4756 sqlite3 *db, /* Database to be rekeyed */ 4757 const void *pKey, int nKey /* The new key */ 4758); 4759SQLITE_API int SQLITE_STDCALL sqlite3_rekey_v2( 4760 sqlite3 *db, /* Database to be rekeyed */ 4761 const char *zDbName, /* Name of the database */ 4762 const void *pKey, int nKey /* The new key */ 4763); 4764 4765/* 4766** Specify the activation key for a SEE database. Unless 4767** activated, none of the SEE routines will work. 4768*/ 4769SQLITE_API void SQLITE_STDCALL sqlite3_activate_see( 4770 const char *zPassPhrase /* Activation phrase */ 4771); 4772#endif 4773 4774#ifdef SQLITE_ENABLE_CEROD 4775/* 4776** Specify the activation key for a CEROD database. Unless 4777** activated, none of the CEROD routines will work. 4778*/ 4779SQLITE_API void SQLITE_STDCALL sqlite3_activate_cerod( 4780 const char *zPassPhrase /* Activation phrase */ 4781); 4782#endif 4783 4784/* 4785** CAPI3REF: Suspend Execution For A Short Time 4786** 4787** The sqlite3_sleep() function causes the current thread to suspend execution 4788** for at least a number of milliseconds specified in its parameter. 4789** 4790** If the operating system does not support sleep requests with 4791** millisecond time resolution, then the time will be rounded up to 4792** the nearest second. The number of milliseconds of sleep actually 4793** requested from the operating system is returned. 4794** 4795** ^SQLite implements this interface by calling the xSleep() 4796** method of the default [sqlite3_vfs] object. If the xSleep() method 4797** of the default VFS is not implemented correctly, or not implemented at 4798** all, then the behavior of sqlite3_sleep() may deviate from the description 4799** in the previous paragraphs. 4800*/ 4801SQLITE_API int SQLITE_STDCALL sqlite3_sleep(int); 4802 4803/* 4804** CAPI3REF: Name Of The Folder Holding Temporary Files 4805** 4806** ^(If this global variable is made to point to a string which is 4807** the name of a folder (a.k.a. directory), then all temporary files 4808** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4809** will be placed in that directory.)^ ^If this variable 4810** is a NULL pointer, then SQLite performs a search for an appropriate 4811** temporary file directory. 4812** 4813** Applications are strongly discouraged from using this global variable. 4814** It is required to set a temporary folder on Windows Runtime (WinRT). 4815** But for all other platforms, it is highly recommended that applications 4816** neither read nor write this variable. This global variable is a relic 4817** that exists for backwards compatibility of legacy applications and should 4818** be avoided in new projects. 4819** 4820** It is not safe to read or modify this variable in more than one 4821** thread at a time. It is not safe to read or modify this variable 4822** if a [database connection] is being used at the same time in a separate 4823** thread. 4824** It is intended that this variable be set once 4825** as part of process initialization and before any SQLite interface 4826** routines have been called and that this variable remain unchanged 4827** thereafter. 4828** 4829** ^The [temp_store_directory pragma] may modify this variable and cause 4830** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4831** the [temp_store_directory pragma] always assumes that any string 4832** that this variable points to is held in memory obtained from 4833** [sqlite3_malloc] and the pragma may attempt to free that memory 4834** using [sqlite3_free]. 4835** Hence, if this variable is modified directly, either it should be 4836** made NULL or made to point to memory obtained from [sqlite3_malloc] 4837** or else the use of the [temp_store_directory pragma] should be avoided. 4838** Except when requested by the [temp_store_directory pragma], SQLite 4839** does not free the memory that sqlite3_temp_directory points to. If 4840** the application wants that memory to be freed, it must do 4841** so itself, taking care to only do so after all [database connection] 4842** objects have been destroyed. 4843** 4844** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4845** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4846** features that require the use of temporary files may fail. Here is an 4847** example of how to do this using C++ with the Windows Runtime: 4848** 4849** <blockquote><pre> 4850** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4851** TemporaryFolder->Path->Data(); 4852** char zPathBuf[MAX_PATH + 1]; 4853** memset(zPathBuf, 0, sizeof(zPathBuf)); 4854** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4855** NULL, NULL); 4856** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4857** </pre></blockquote> 4858*/ 4859SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 4860 4861/* 4862** CAPI3REF: Name Of The Folder Holding Database Files 4863** 4864** ^(If this global variable is made to point to a string which is 4865** the name of a folder (a.k.a. directory), then all database files 4866** specified with a relative pathname and created or accessed by 4867** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4868** to be relative to that directory.)^ ^If this variable is a NULL 4869** pointer, then SQLite assumes that all database files specified 4870** with a relative pathname are relative to the current directory 4871** for the process. Only the windows VFS makes use of this global 4872** variable; it is ignored by the unix VFS. 4873** 4874** Changing the value of this variable while a database connection is 4875** open can result in a corrupt database. 4876** 4877** It is not safe to read or modify this variable in more than one 4878** thread at a time. It is not safe to read or modify this variable 4879** if a [database connection] is being used at the same time in a separate 4880** thread. 4881** It is intended that this variable be set once 4882** as part of process initialization and before any SQLite interface 4883** routines have been called and that this variable remain unchanged 4884** thereafter. 4885** 4886** ^The [data_store_directory pragma] may modify this variable and cause 4887** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4888** the [data_store_directory pragma] always assumes that any string 4889** that this variable points to is held in memory obtained from 4890** [sqlite3_malloc] and the pragma may attempt to free that memory 4891** using [sqlite3_free]. 4892** Hence, if this variable is modified directly, either it should be 4893** made NULL or made to point to memory obtained from [sqlite3_malloc] 4894** or else the use of the [data_store_directory pragma] should be avoided. 4895*/ 4896SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory; 4897 4898/* 4899** CAPI3REF: Test For Auto-Commit Mode 4900** KEYWORDS: {autocommit mode} 4901** 4902** ^The sqlite3_get_autocommit() interface returns non-zero or 4903** zero if the given database connection is or is not in autocommit mode, 4904** respectively. ^Autocommit mode is on by default. 4905** ^Autocommit mode is disabled by a [BEGIN] statement. 4906** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4907** 4908** If certain kinds of errors occur on a statement within a multi-statement 4909** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4910** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4911** transaction might be rolled back automatically. The only way to 4912** find out whether SQLite automatically rolled back the transaction after 4913** an error is to use this function. 4914** 4915** If another thread changes the autocommit status of the database 4916** connection while this routine is running, then the return value 4917** is undefined. 4918*/ 4919SQLITE_API int SQLITE_STDCALL sqlite3_get_autocommit(sqlite3*); 4920 4921/* 4922** CAPI3REF: Find The Database Handle Of A Prepared Statement 4923** 4924** ^The sqlite3_db_handle interface returns the [database connection] handle 4925** to which a [prepared statement] belongs. ^The [database connection] 4926** returned by sqlite3_db_handle is the same [database connection] 4927** that was the first argument 4928** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4929** create the statement in the first place. 4930*/ 4931SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_db_handle(sqlite3_stmt*); 4932 4933/* 4934** CAPI3REF: Return The Filename For A Database Connection 4935** 4936** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4937** associated with database N of connection D. ^The main database file 4938** has the name "main". If there is no attached database N on the database 4939** connection D, or if database N is a temporary or in-memory database, then 4940** a NULL pointer is returned. 4941** 4942** ^The filename returned by this function is the output of the 4943** xFullPathname method of the [VFS]. ^In other words, the filename 4944** will be an absolute pathname, even if the filename used 4945** to open the database originally was a URI or relative pathname. 4946*/ 4947SQLITE_API const char *SQLITE_STDCALL sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4948 4949/* 4950** CAPI3REF: Determine if a database is read-only 4951** 4952** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4953** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4954** the name of a database on connection D. 4955*/ 4956SQLITE_API int SQLITE_STDCALL sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4957 4958/* 4959** CAPI3REF: Find the next prepared statement 4960** 4961** ^This interface returns a pointer to the next [prepared statement] after 4962** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4963** then this interface returns a pointer to the first prepared statement 4964** associated with the database connection pDb. ^If no prepared statement 4965** satisfies the conditions of this routine, it returns NULL. 4966** 4967** The [database connection] pointer D in a call to 4968** [sqlite3_next_stmt(D,S)] must refer to an open database 4969** connection and in particular must not be a NULL pointer. 4970*/ 4971SQLITE_API sqlite3_stmt *SQLITE_STDCALL sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4972 4973/* 4974** CAPI3REF: Commit And Rollback Notification Callbacks 4975** 4976** ^The sqlite3_commit_hook() interface registers a callback 4977** function to be invoked whenever a transaction is [COMMIT | committed]. 4978** ^Any callback set by a previous call to sqlite3_commit_hook() 4979** for the same database connection is overridden. 4980** ^The sqlite3_rollback_hook() interface registers a callback 4981** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4982** ^Any callback set by a previous call to sqlite3_rollback_hook() 4983** for the same database connection is overridden. 4984** ^The pArg argument is passed through to the callback. 4985** ^If the callback on a commit hook function returns non-zero, 4986** then the commit is converted into a rollback. 4987** 4988** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4989** return the P argument from the previous call of the same function 4990** on the same [database connection] D, or NULL for 4991** the first call for each function on D. 4992** 4993** The commit and rollback hook callbacks are not reentrant. 4994** The callback implementation must not do anything that will modify 4995** the database connection that invoked the callback. Any actions 4996** to modify the database connection must be deferred until after the 4997** completion of the [sqlite3_step()] call that triggered the commit 4998** or rollback hook in the first place. 4999** Note that running any other SQL statements, including SELECT statements, 5000** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5001** the database connections for the meaning of "modify" in this paragraph. 5002** 5003** ^Registering a NULL function disables the callback. 5004** 5005** ^When the commit hook callback routine returns zero, the [COMMIT] 5006** operation is allowed to continue normally. ^If the commit hook 5007** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5008** ^The rollback hook is invoked on a rollback that results from a commit 5009** hook returning non-zero, just as it would be with any other rollback. 5010** 5011** ^For the purposes of this API, a transaction is said to have been 5012** rolled back if an explicit "ROLLBACK" statement is executed, or 5013** an error or constraint causes an implicit rollback to occur. 5014** ^The rollback callback is not invoked if a transaction is 5015** automatically rolled back because the database connection is closed. 5016** 5017** See also the [sqlite3_update_hook()] interface. 5018*/ 5019SQLITE_API void *SQLITE_STDCALL sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5020SQLITE_API void *SQLITE_STDCALL sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5021 5022/* 5023** CAPI3REF: Data Change Notification Callbacks 5024** 5025** ^The sqlite3_update_hook() interface registers a callback function 5026** with the [database connection] identified by the first argument 5027** to be invoked whenever a row is updated, inserted or deleted in 5028** a rowid table. 5029** ^Any callback set by a previous call to this function 5030** for the same database connection is overridden. 5031** 5032** ^The second argument is a pointer to the function to invoke when a 5033** row is updated, inserted or deleted in a rowid table. 5034** ^The first argument to the callback is a copy of the third argument 5035** to sqlite3_update_hook(). 5036** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5037** or [SQLITE_UPDATE], depending on the operation that caused the callback 5038** to be invoked. 5039** ^The third and fourth arguments to the callback contain pointers to the 5040** database and table name containing the affected row. 5041** ^The final callback parameter is the [rowid] of the row. 5042** ^In the case of an update, this is the [rowid] after the update takes place. 5043** 5044** ^(The update hook is not invoked when internal system tables are 5045** modified (i.e. sqlite_master and sqlite_sequence).)^ 5046** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5047** 5048** ^In the current implementation, the update hook 5049** is not invoked when duplication rows are deleted because of an 5050** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5051** invoked when rows are deleted using the [truncate optimization]. 5052** The exceptions defined in this paragraph might change in a future 5053** release of SQLite. 5054** 5055** The update hook implementation must not do anything that will modify 5056** the database connection that invoked the update hook. Any actions 5057** to modify the database connection must be deferred until after the 5058** completion of the [sqlite3_step()] call that triggered the update hook. 5059** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5060** database connections for the meaning of "modify" in this paragraph. 5061** 5062** ^The sqlite3_update_hook(D,C,P) function 5063** returns the P argument from the previous call 5064** on the same [database connection] D, or NULL for 5065** the first call on D. 5066** 5067** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 5068** interfaces. 5069*/ 5070SQLITE_API void *SQLITE_STDCALL sqlite3_update_hook( 5071 sqlite3*, 5072 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5073 void* 5074); 5075 5076/* 5077** CAPI3REF: Enable Or Disable Shared Pager Cache 5078** 5079** ^(This routine enables or disables the sharing of the database cache 5080** and schema data structures between [database connection | connections] 5081** to the same database. Sharing is enabled if the argument is true 5082** and disabled if the argument is false.)^ 5083** 5084** ^Cache sharing is enabled and disabled for an entire process. 5085** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 5086** sharing was enabled or disabled for each thread separately. 5087** 5088** ^(The cache sharing mode set by this interface effects all subsequent 5089** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5090** Existing database connections continue use the sharing mode 5091** that was in effect at the time they were opened.)^ 5092** 5093** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5094** successfully. An [error code] is returned otherwise.)^ 5095** 5096** ^Shared cache is disabled by default. But this might change in 5097** future releases of SQLite. Applications that care about shared 5098** cache setting should set it explicitly. 5099** 5100** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5101** and will always return SQLITE_MISUSE. On those systems, 5102** shared cache mode should be enabled per-database connection via 5103** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5104** 5105** This interface is threadsafe on processors where writing a 5106** 32-bit integer is atomic. 5107** 5108** See Also: [SQLite Shared-Cache Mode] 5109*/ 5110SQLITE_API int SQLITE_STDCALL sqlite3_enable_shared_cache(int); 5111 5112/* 5113** CAPI3REF: Attempt To Free Heap Memory 5114** 5115** ^The sqlite3_release_memory() interface attempts to free N bytes 5116** of heap memory by deallocating non-essential memory allocations 5117** held by the database library. Memory used to cache database 5118** pages to improve performance is an example of non-essential memory. 5119** ^sqlite3_release_memory() returns the number of bytes actually freed, 5120** which might be more or less than the amount requested. 5121** ^The sqlite3_release_memory() routine is a no-op returning zero 5122** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5123** 5124** See also: [sqlite3_db_release_memory()] 5125*/ 5126SQLITE_API int SQLITE_STDCALL sqlite3_release_memory(int); 5127 5128/* 5129** CAPI3REF: Free Memory Used By A Database Connection 5130** 5131** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5132** memory as possible from database connection D. Unlike the 5133** [sqlite3_release_memory()] interface, this interface is in effect even 5134** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5135** omitted. 5136** 5137** See also: [sqlite3_release_memory()] 5138*/ 5139SQLITE_API int SQLITE_STDCALL sqlite3_db_release_memory(sqlite3*); 5140 5141/* 5142** CAPI3REF: Impose A Limit On Heap Size 5143** 5144** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5145** soft limit on the amount of heap memory that may be allocated by SQLite. 5146** ^SQLite strives to keep heap memory utilization below the soft heap 5147** limit by reducing the number of pages held in the page cache 5148** as heap memory usages approaches the limit. 5149** ^The soft heap limit is "soft" because even though SQLite strives to stay 5150** below the limit, it will exceed the limit rather than generate 5151** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5152** is advisory only. 5153** 5154** ^The return value from sqlite3_soft_heap_limit64() is the size of 5155** the soft heap limit prior to the call, or negative in the case of an 5156** error. ^If the argument N is negative 5157** then no change is made to the soft heap limit. Hence, the current 5158** size of the soft heap limit can be determined by invoking 5159** sqlite3_soft_heap_limit64() with a negative argument. 5160** 5161** ^If the argument N is zero then the soft heap limit is disabled. 5162** 5163** ^(The soft heap limit is not enforced in the current implementation 5164** if one or more of following conditions are true: 5165** 5166** <ul> 5167** <li> The soft heap limit is set to zero. 5168** <li> Memory accounting is disabled using a combination of the 5169** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5170** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5171** <li> An alternative page cache implementation is specified using 5172** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5173** <li> The page cache allocates from its own memory pool supplied 5174** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5175** from the heap. 5176** </ul>)^ 5177** 5178** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 5179** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5180** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5181** the soft heap limit is enforced on every memory allocation. Without 5182** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5183** when memory is allocated by the page cache. Testing suggests that because 5184** the page cache is the predominate memory user in SQLite, most 5185** applications will achieve adequate soft heap limit enforcement without 5186** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5187** 5188** The circumstances under which SQLite will enforce the soft heap limit may 5189** changes in future releases of SQLite. 5190*/ 5191SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_soft_heap_limit64(sqlite3_int64 N); 5192 5193/* 5194** CAPI3REF: Deprecated Soft Heap Limit Interface 5195** DEPRECATED 5196** 5197** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5198** interface. This routine is provided for historical compatibility 5199** only. All new applications should use the 5200** [sqlite3_soft_heap_limit64()] interface rather than this one. 5201*/ 5202SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_soft_heap_limit(int N); 5203 5204 5205/* 5206** CAPI3REF: Extract Metadata About A Column Of A Table 5207** 5208** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5209** information about column C of table T in database D 5210** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5211** interface returns SQLITE_OK and fills in the non-NULL pointers in 5212** the final five arguments with appropriate values if the specified 5213** column exists. ^The sqlite3_table_column_metadata() interface returns 5214** SQLITE_ERROR and if the specified column does not exist. 5215** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5216** NULL pointer, then this routine simply checks for the existance of the 5217** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5218** does not. 5219** 5220** ^The column is identified by the second, third and fourth parameters to 5221** this function. ^(The second parameter is either the name of the database 5222** (i.e. "main", "temp", or an attached database) containing the specified 5223** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5224** for the table using the same algorithm used by the database engine to 5225** resolve unqualified table references. 5226** 5227** ^The third and fourth parameters to this function are the table and column 5228** name of the desired column, respectively. 5229** 5230** ^Metadata is returned by writing to the memory locations passed as the 5th 5231** and subsequent parameters to this function. ^Any of these arguments may be 5232** NULL, in which case the corresponding element of metadata is omitted. 5233** 5234** ^(<blockquote> 5235** <table border="1"> 5236** <tr><th> Parameter <th> Output<br>Type <th> Description 5237** 5238** <tr><td> 5th <td> const char* <td> Data type 5239** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5240** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5241** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5242** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5243** </table> 5244** </blockquote>)^ 5245** 5246** ^The memory pointed to by the character pointers returned for the 5247** declaration type and collation sequence is valid until the next 5248** call to any SQLite API function. 5249** 5250** ^If the specified table is actually a view, an [error code] is returned. 5251** 5252** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5253** is not a [WITHOUT ROWID] table and an 5254** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5255** parameters are set for the explicitly declared column. ^(If there is no 5256** [INTEGER PRIMARY KEY] column, then the outputs 5257** for the [rowid] are set as follows: 5258** 5259** <pre> 5260** data type: "INTEGER" 5261** collation sequence: "BINARY" 5262** not null: 0 5263** primary key: 1 5264** auto increment: 0 5265** </pre>)^ 5266** 5267** ^This function causes all database schemas to be read from disk and 5268** parsed, if that has not already been done, and returns an error if 5269** any errors are encountered while loading the schema. 5270*/ 5271SQLITE_API int SQLITE_STDCALL sqlite3_table_column_metadata( 5272 sqlite3 *db, /* Connection handle */ 5273 const char *zDbName, /* Database name or NULL */ 5274 const char *zTableName, /* Table name */ 5275 const char *zColumnName, /* Column name */ 5276 char const **pzDataType, /* OUTPUT: Declared data type */ 5277 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5278 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5279 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5280 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5281); 5282 5283/* 5284** CAPI3REF: Load An Extension 5285** 5286** ^This interface loads an SQLite extension library from the named file. 5287** 5288** ^The sqlite3_load_extension() interface attempts to load an 5289** [SQLite extension] library contained in the file zFile. If 5290** the file cannot be loaded directly, attempts are made to load 5291** with various operating-system specific extensions added. 5292** So for example, if "samplelib" cannot be loaded, then names like 5293** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5294** be tried also. 5295** 5296** ^The entry point is zProc. 5297** ^(zProc may be 0, in which case SQLite will try to come up with an 5298** entry point name on its own. It first tries "sqlite3_extension_init". 5299** If that does not work, it constructs a name "sqlite3_X_init" where the 5300** X is consists of the lower-case equivalent of all ASCII alphabetic 5301** characters in the filename from the last "/" to the first following 5302** "." and omitting any initial "lib".)^ 5303** ^The sqlite3_load_extension() interface returns 5304** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5305** ^If an error occurs and pzErrMsg is not 0, then the 5306** [sqlite3_load_extension()] interface shall attempt to 5307** fill *pzErrMsg with error message text stored in memory 5308** obtained from [sqlite3_malloc()]. The calling function 5309** should free this memory by calling [sqlite3_free()]. 5310** 5311** ^Extension loading must be enabled using 5312** [sqlite3_enable_load_extension()] prior to calling this API, 5313** otherwise an error will be returned. 5314** 5315** See also the [load_extension() SQL function]. 5316*/ 5317SQLITE_API int SQLITE_STDCALL sqlite3_load_extension( 5318 sqlite3 *db, /* Load the extension into this database connection */ 5319 const char *zFile, /* Name of the shared library containing extension */ 5320 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5321 char **pzErrMsg /* Put error message here if not 0 */ 5322); 5323 5324/* 5325** CAPI3REF: Enable Or Disable Extension Loading 5326** 5327** ^So as not to open security holes in older applications that are 5328** unprepared to deal with [extension loading], and as a means of disabling 5329** [extension loading] while evaluating user-entered SQL, the following API 5330** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5331** 5332** ^Extension loading is off by default. 5333** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5334** to turn extension loading on and call it with onoff==0 to turn 5335** it back off again. 5336*/ 5337SQLITE_API int SQLITE_STDCALL sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5338 5339/* 5340** CAPI3REF: Automatically Load Statically Linked Extensions 5341** 5342** ^This interface causes the xEntryPoint() function to be invoked for 5343** each new [database connection] that is created. The idea here is that 5344** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5345** that is to be automatically loaded into all new database connections. 5346** 5347** ^(Even though the function prototype shows that xEntryPoint() takes 5348** no arguments and returns void, SQLite invokes xEntryPoint() with three 5349** arguments and expects and integer result as if the signature of the 5350** entry point where as follows: 5351** 5352** <blockquote><pre> 5353** int xEntryPoint( 5354** sqlite3 *db, 5355** const char **pzErrMsg, 5356** const struct sqlite3_api_routines *pThunk 5357** ); 5358** </pre></blockquote>)^ 5359** 5360** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5361** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5362** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5363** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5364** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5365** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5366** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5367** 5368** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5369** on the list of automatic extensions is a harmless no-op. ^No entry point 5370** will be called more than once for each database connection that is opened. 5371** 5372** See also: [sqlite3_reset_auto_extension()] 5373** and [sqlite3_cancel_auto_extension()] 5374*/ 5375SQLITE_API int SQLITE_STDCALL sqlite3_auto_extension(void (*xEntryPoint)(void)); 5376 5377/* 5378** CAPI3REF: Cancel Automatic Extension Loading 5379** 5380** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5381** initialization routine X that was registered using a prior call to 5382** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5383** routine returns 1 if initialization routine X was successfully 5384** unregistered and it returns 0 if X was not on the list of initialization 5385** routines. 5386*/ 5387SQLITE_API int SQLITE_STDCALL sqlite3_cancel_auto_extension(void (*xEntryPoint)(void)); 5388 5389/* 5390** CAPI3REF: Reset Automatic Extension Loading 5391** 5392** ^This interface disables all automatic extensions previously 5393** registered using [sqlite3_auto_extension()]. 5394*/ 5395SQLITE_API void SQLITE_STDCALL sqlite3_reset_auto_extension(void); 5396 5397/* 5398** The interface to the virtual-table mechanism is currently considered 5399** to be experimental. The interface might change in incompatible ways. 5400** If this is a problem for you, do not use the interface at this time. 5401** 5402** When the virtual-table mechanism stabilizes, we will declare the 5403** interface fixed, support it indefinitely, and remove this comment. 5404*/ 5405 5406/* 5407** Structures used by the virtual table interface 5408*/ 5409typedef struct sqlite3_vtab sqlite3_vtab; 5410typedef struct sqlite3_index_info sqlite3_index_info; 5411typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5412typedef struct sqlite3_module sqlite3_module; 5413 5414/* 5415** CAPI3REF: Virtual Table Object 5416** KEYWORDS: sqlite3_module {virtual table module} 5417** 5418** This structure, sometimes called a "virtual table module", 5419** defines the implementation of a [virtual tables]. 5420** This structure consists mostly of methods for the module. 5421** 5422** ^A virtual table module is created by filling in a persistent 5423** instance of this structure and passing a pointer to that instance 5424** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5425** ^The registration remains valid until it is replaced by a different 5426** module or until the [database connection] closes. The content 5427** of this structure must not change while it is registered with 5428** any database connection. 5429*/ 5430struct sqlite3_module { 5431 int iVersion; 5432 int (*xCreate)(sqlite3*, void *pAux, 5433 int argc, const char *const*argv, 5434 sqlite3_vtab **ppVTab, char**); 5435 int (*xConnect)(sqlite3*, void *pAux, 5436 int argc, const char *const*argv, 5437 sqlite3_vtab **ppVTab, char**); 5438 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5439 int (*xDisconnect)(sqlite3_vtab *pVTab); 5440 int (*xDestroy)(sqlite3_vtab *pVTab); 5441 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5442 int (*xClose)(sqlite3_vtab_cursor*); 5443 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5444 int argc, sqlite3_value **argv); 5445 int (*xNext)(sqlite3_vtab_cursor*); 5446 int (*xEof)(sqlite3_vtab_cursor*); 5447 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5448 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5449 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5450 int (*xBegin)(sqlite3_vtab *pVTab); 5451 int (*xSync)(sqlite3_vtab *pVTab); 5452 int (*xCommit)(sqlite3_vtab *pVTab); 5453 int (*xRollback)(sqlite3_vtab *pVTab); 5454 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5455 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5456 void **ppArg); 5457 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5458 /* The methods above are in version 1 of the sqlite_module object. Those 5459 ** below are for version 2 and greater. */ 5460 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5461 int (*xRelease)(sqlite3_vtab *pVTab, int); 5462 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5463}; 5464 5465/* 5466** CAPI3REF: Virtual Table Indexing Information 5467** KEYWORDS: sqlite3_index_info 5468** 5469** The sqlite3_index_info structure and its substructures is used as part 5470** of the [virtual table] interface to 5471** pass information into and receive the reply from the [xBestIndex] 5472** method of a [virtual table module]. The fields under **Inputs** are the 5473** inputs to xBestIndex and are read-only. xBestIndex inserts its 5474** results into the **Outputs** fields. 5475** 5476** ^(The aConstraint[] array records WHERE clause constraints of the form: 5477** 5478** <blockquote>column OP expr</blockquote> 5479** 5480** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5481** stored in aConstraint[].op using one of the 5482** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5483** ^(The index of the column is stored in 5484** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5485** expr on the right-hand side can be evaluated (and thus the constraint 5486** is usable) and false if it cannot.)^ 5487** 5488** ^The optimizer automatically inverts terms of the form "expr OP column" 5489** and makes other simplifications to the WHERE clause in an attempt to 5490** get as many WHERE clause terms into the form shown above as possible. 5491** ^The aConstraint[] array only reports WHERE clause terms that are 5492** relevant to the particular virtual table being queried. 5493** 5494** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5495** ^Each term of aOrderBy records a column of the ORDER BY clause. 5496** 5497** The [xBestIndex] method must fill aConstraintUsage[] with information 5498** about what parameters to pass to xFilter. ^If argvIndex>0 then 5499** the right-hand side of the corresponding aConstraint[] is evaluated 5500** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5501** is true, then the constraint is assumed to be fully handled by the 5502** virtual table and is not checked again by SQLite.)^ 5503** 5504** ^The idxNum and idxPtr values are recorded and passed into the 5505** [xFilter] method. 5506** ^[sqlite3_free()] is used to free idxPtr if and only if 5507** needToFreeIdxPtr is true. 5508** 5509** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5510** the correct order to satisfy the ORDER BY clause so that no separate 5511** sorting step is required. 5512** 5513** ^The estimatedCost value is an estimate of the cost of a particular 5514** strategy. A cost of N indicates that the cost of the strategy is similar 5515** to a linear scan of an SQLite table with N rows. A cost of log(N) 5516** indicates that the expense of the operation is similar to that of a 5517** binary search on a unique indexed field of an SQLite table with N rows. 5518** 5519** ^The estimatedRows value is an estimate of the number of rows that 5520** will be returned by the strategy. 5521** 5522** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 5523** structure for SQLite version 3.8.2. If a virtual table extension is 5524** used with an SQLite version earlier than 3.8.2, the results of attempting 5525** to read or write the estimatedRows field are undefined (but are likely 5526** to included crashing the application). The estimatedRows field should 5527** therefore only be used if [sqlite3_libversion_number()] returns a 5528** value greater than or equal to 3008002. 5529*/ 5530struct sqlite3_index_info { 5531 /* Inputs */ 5532 int nConstraint; /* Number of entries in aConstraint */ 5533 struct sqlite3_index_constraint { 5534 int iColumn; /* Column on left-hand side of constraint */ 5535 unsigned char op; /* Constraint operator */ 5536 unsigned char usable; /* True if this constraint is usable */ 5537 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5538 } *aConstraint; /* Table of WHERE clause constraints */ 5539 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5540 struct sqlite3_index_orderby { 5541 int iColumn; /* Column number */ 5542 unsigned char desc; /* True for DESC. False for ASC. */ 5543 } *aOrderBy; /* The ORDER BY clause */ 5544 /* Outputs */ 5545 struct sqlite3_index_constraint_usage { 5546 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5547 unsigned char omit; /* Do not code a test for this constraint */ 5548 } *aConstraintUsage; 5549 int idxNum; /* Number used to identify the index */ 5550 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5551 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5552 int orderByConsumed; /* True if output is already ordered */ 5553 double estimatedCost; /* Estimated cost of using this index */ 5554 /* Fields below are only available in SQLite 3.8.2 and later */ 5555 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 5556}; 5557 5558/* 5559** CAPI3REF: Virtual Table Constraint Operator Codes 5560** 5561** These macros defined the allowed values for the 5562** [sqlite3_index_info].aConstraint[].op field. Each value represents 5563** an operator that is part of a constraint term in the wHERE clause of 5564** a query that uses a [virtual table]. 5565*/ 5566#define SQLITE_INDEX_CONSTRAINT_EQ 2 5567#define SQLITE_INDEX_CONSTRAINT_GT 4 5568#define SQLITE_INDEX_CONSTRAINT_LE 8 5569#define SQLITE_INDEX_CONSTRAINT_LT 16 5570#define SQLITE_INDEX_CONSTRAINT_GE 32 5571#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5572 5573/* 5574** CAPI3REF: Register A Virtual Table Implementation 5575** 5576** ^These routines are used to register a new [virtual table module] name. 5577** ^Module names must be registered before 5578** creating a new [virtual table] using the module and before using a 5579** preexisting [virtual table] for the module. 5580** 5581** ^The module name is registered on the [database connection] specified 5582** by the first parameter. ^The name of the module is given by the 5583** second parameter. ^The third parameter is a pointer to 5584** the implementation of the [virtual table module]. ^The fourth 5585** parameter is an arbitrary client data pointer that is passed through 5586** into the [xCreate] and [xConnect] methods of the virtual table module 5587** when a new virtual table is be being created or reinitialized. 5588** 5589** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5590** is a pointer to a destructor for the pClientData. ^SQLite will 5591** invoke the destructor function (if it is not NULL) when SQLite 5592** no longer needs the pClientData pointer. ^The destructor will also 5593** be invoked if the call to sqlite3_create_module_v2() fails. 5594** ^The sqlite3_create_module() 5595** interface is equivalent to sqlite3_create_module_v2() with a NULL 5596** destructor. 5597*/ 5598SQLITE_API int SQLITE_STDCALL sqlite3_create_module( 5599 sqlite3 *db, /* SQLite connection to register module with */ 5600 const char *zName, /* Name of the module */ 5601 const sqlite3_module *p, /* Methods for the module */ 5602 void *pClientData /* Client data for xCreate/xConnect */ 5603); 5604SQLITE_API int SQLITE_STDCALL sqlite3_create_module_v2( 5605 sqlite3 *db, /* SQLite connection to register module with */ 5606 const char *zName, /* Name of the module */ 5607 const sqlite3_module *p, /* Methods for the module */ 5608 void *pClientData, /* Client data for xCreate/xConnect */ 5609 void(*xDestroy)(void*) /* Module destructor function */ 5610); 5611 5612/* 5613** CAPI3REF: Virtual Table Instance Object 5614** KEYWORDS: sqlite3_vtab 5615** 5616** Every [virtual table module] implementation uses a subclass 5617** of this object to describe a particular instance 5618** of the [virtual table]. Each subclass will 5619** be tailored to the specific needs of the module implementation. 5620** The purpose of this superclass is to define certain fields that are 5621** common to all module implementations. 5622** 5623** ^Virtual tables methods can set an error message by assigning a 5624** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5625** take care that any prior string is freed by a call to [sqlite3_free()] 5626** prior to assigning a new string to zErrMsg. ^After the error message 5627** is delivered up to the client application, the string will be automatically 5628** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5629*/ 5630struct sqlite3_vtab { 5631 const sqlite3_module *pModule; /* The module for this virtual table */ 5632 int nRef; /* Number of open cursors */ 5633 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5634 /* Virtual table implementations will typically add additional fields */ 5635}; 5636 5637/* 5638** CAPI3REF: Virtual Table Cursor Object 5639** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5640** 5641** Every [virtual table module] implementation uses a subclass of the 5642** following structure to describe cursors that point into the 5643** [virtual table] and are used 5644** to loop through the virtual table. Cursors are created using the 5645** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5646** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5647** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5648** of the module. Each module implementation will define 5649** the content of a cursor structure to suit its own needs. 5650** 5651** This superclass exists in order to define fields of the cursor that 5652** are common to all implementations. 5653*/ 5654struct sqlite3_vtab_cursor { 5655 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5656 /* Virtual table implementations will typically add additional fields */ 5657}; 5658 5659/* 5660** CAPI3REF: Declare The Schema Of A Virtual Table 5661** 5662** ^The [xCreate] and [xConnect] methods of a 5663** [virtual table module] call this interface 5664** to declare the format (the names and datatypes of the columns) of 5665** the virtual tables they implement. 5666*/ 5667SQLITE_API int SQLITE_STDCALL sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5668 5669/* 5670** CAPI3REF: Overload A Function For A Virtual Table 5671** 5672** ^(Virtual tables can provide alternative implementations of functions 5673** using the [xFindFunction] method of the [virtual table module]. 5674** But global versions of those functions 5675** must exist in order to be overloaded.)^ 5676** 5677** ^(This API makes sure a global version of a function with a particular 5678** name and number of parameters exists. If no such function exists 5679** before this API is called, a new function is created.)^ ^The implementation 5680** of the new function always causes an exception to be thrown. So 5681** the new function is not good for anything by itself. Its only 5682** purpose is to be a placeholder function that can be overloaded 5683** by a [virtual table]. 5684*/ 5685SQLITE_API int SQLITE_STDCALL sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5686 5687/* 5688** The interface to the virtual-table mechanism defined above (back up 5689** to a comment remarkably similar to this one) is currently considered 5690** to be experimental. The interface might change in incompatible ways. 5691** If this is a problem for you, do not use the interface at this time. 5692** 5693** When the virtual-table mechanism stabilizes, we will declare the 5694** interface fixed, support it indefinitely, and remove this comment. 5695*/ 5696 5697/* 5698** CAPI3REF: A Handle To An Open BLOB 5699** KEYWORDS: {BLOB handle} {BLOB handles} 5700** 5701** An instance of this object represents an open BLOB on which 5702** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5703** ^Objects of this type are created by [sqlite3_blob_open()] 5704** and destroyed by [sqlite3_blob_close()]. 5705** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5706** can be used to read or write small subsections of the BLOB. 5707** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5708*/ 5709typedef struct sqlite3_blob sqlite3_blob; 5710 5711/* 5712** CAPI3REF: Open A BLOB For Incremental I/O 5713** 5714** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5715** in row iRow, column zColumn, table zTable in database zDb; 5716** in other words, the same BLOB that would be selected by: 5717** 5718** <pre> 5719** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5720** </pre>)^ 5721** 5722** ^(Parameter zDb is not the filename that contains the database, but 5723** rather the symbolic name of the database. For attached databases, this is 5724** the name that appears after the AS keyword in the [ATTACH] statement. 5725** For the main database file, the database name is "main". For TEMP 5726** tables, the database name is "temp".)^ 5727** 5728** ^If the flags parameter is non-zero, then the BLOB is opened for read 5729** and write access. ^If the flags parameter is zero, the BLOB is opened for 5730** read-only access. 5731** 5732** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 5733** in *ppBlob. Otherwise an [error code] is returned and, unless the error 5734** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 5735** the API is not misused, it is always safe to call [sqlite3_blob_close()] 5736** on *ppBlob after this function it returns. 5737** 5738** This function fails with SQLITE_ERROR if any of the following are true: 5739** <ul> 5740** <li> ^(Database zDb does not exist)^, 5741** <li> ^(Table zTable does not exist within database zDb)^, 5742** <li> ^(Table zTable is a WITHOUT ROWID table)^, 5743** <li> ^(Column zColumn does not exist)^, 5744** <li> ^(Row iRow is not present in the table)^, 5745** <li> ^(The specified column of row iRow contains a value that is not 5746** a TEXT or BLOB value)^, 5747** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 5748** constraint and the blob is being opened for read/write access)^, 5749** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 5750** column zColumn is part of a [child key] definition and the blob is 5751** being opened for read/write access)^. 5752** </ul> 5753** 5754** ^Unless it returns SQLITE_MISUSE, this function sets the 5755** [database connection] error code and message accessible via 5756** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 5757** 5758** 5759** ^(If the row that a BLOB handle points to is modified by an 5760** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5761** then the BLOB handle is marked as "expired". 5762** This is true if any column of the row is changed, even a column 5763** other than the one the BLOB handle is open on.)^ 5764** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5765** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5766** ^(Changes written into a BLOB prior to the BLOB expiring are not 5767** rolled back by the expiration of the BLOB. Such changes will eventually 5768** commit if the transaction continues to completion.)^ 5769** 5770** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5771** the opened blob. ^The size of a blob may not be changed by this 5772** interface. Use the [UPDATE] SQL command to change the size of a 5773** blob. 5774** 5775** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5776** and the built-in [zeroblob] SQL function may be used to create a 5777** zero-filled blob to read or write using the incremental-blob interface. 5778** 5779** To avoid a resource leak, every open [BLOB handle] should eventually 5780** be released by a call to [sqlite3_blob_close()]. 5781*/ 5782SQLITE_API int SQLITE_STDCALL sqlite3_blob_open( 5783 sqlite3*, 5784 const char *zDb, 5785 const char *zTable, 5786 const char *zColumn, 5787 sqlite3_int64 iRow, 5788 int flags, 5789 sqlite3_blob **ppBlob 5790); 5791 5792/* 5793** CAPI3REF: Move a BLOB Handle to a New Row 5794** 5795** ^This function is used to move an existing blob handle so that it points 5796** to a different row of the same database table. ^The new row is identified 5797** by the rowid value passed as the second argument. Only the row can be 5798** changed. ^The database, table and column on which the blob handle is open 5799** remain the same. Moving an existing blob handle to a new row can be 5800** faster than closing the existing handle and opening a new one. 5801** 5802** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5803** it must exist and there must be either a blob or text value stored in 5804** the nominated column.)^ ^If the new row is not present in the table, or if 5805** it does not contain a blob or text value, or if another error occurs, an 5806** SQLite error code is returned and the blob handle is considered aborted. 5807** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5808** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5809** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5810** always returns zero. 5811** 5812** ^This function sets the database handle error code and message. 5813*/ 5814SQLITE_API SQLITE_EXPERIMENTAL int SQLITE_STDCALL sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5815 5816/* 5817** CAPI3REF: Close A BLOB Handle 5818** 5819** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 5820** unconditionally. Even if this routine returns an error code, the 5821** handle is still closed.)^ 5822** 5823** ^If the blob handle being closed was opened for read-write access, and if 5824** the database is in auto-commit mode and there are no other open read-write 5825** blob handles or active write statements, the current transaction is 5826** committed. ^If an error occurs while committing the transaction, an error 5827** code is returned and the transaction rolled back. 5828** 5829** Calling this function with an argument that is not a NULL pointer or an 5830** open blob handle results in undefined behaviour. ^Calling this routine 5831** with a null pointer (such as would be returned by a failed call to 5832** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 5833** is passed a valid open blob handle, the values returned by the 5834** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 5835*/ 5836SQLITE_API int SQLITE_STDCALL sqlite3_blob_close(sqlite3_blob *); 5837 5838/* 5839** CAPI3REF: Return The Size Of An Open BLOB 5840** 5841** ^Returns the size in bytes of the BLOB accessible via the 5842** successfully opened [BLOB handle] in its only argument. ^The 5843** incremental blob I/O routines can only read or overwriting existing 5844** blob content; they cannot change the size of a blob. 5845** 5846** This routine only works on a [BLOB handle] which has been created 5847** by a prior successful call to [sqlite3_blob_open()] and which has not 5848** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5849** to this routine results in undefined and probably undesirable behavior. 5850*/ 5851SQLITE_API int SQLITE_STDCALL sqlite3_blob_bytes(sqlite3_blob *); 5852 5853/* 5854** CAPI3REF: Read Data From A BLOB Incrementally 5855** 5856** ^(This function is used to read data from an open [BLOB handle] into a 5857** caller-supplied buffer. N bytes of data are copied into buffer Z 5858** from the open BLOB, starting at offset iOffset.)^ 5859** 5860** ^If offset iOffset is less than N bytes from the end of the BLOB, 5861** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5862** less than zero, [SQLITE_ERROR] is returned and no data is read. 5863** ^The size of the blob (and hence the maximum value of N+iOffset) 5864** can be determined using the [sqlite3_blob_bytes()] interface. 5865** 5866** ^An attempt to read from an expired [BLOB handle] fails with an 5867** error code of [SQLITE_ABORT]. 5868** 5869** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5870** Otherwise, an [error code] or an [extended error code] is returned.)^ 5871** 5872** This routine only works on a [BLOB handle] which has been created 5873** by a prior successful call to [sqlite3_blob_open()] and which has not 5874** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5875** to this routine results in undefined and probably undesirable behavior. 5876** 5877** See also: [sqlite3_blob_write()]. 5878*/ 5879SQLITE_API int SQLITE_STDCALL sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5880 5881/* 5882** CAPI3REF: Write Data Into A BLOB Incrementally 5883** 5884** ^(This function is used to write data into an open [BLOB handle] from a 5885** caller-supplied buffer. N bytes of data are copied from the buffer Z 5886** into the open BLOB, starting at offset iOffset.)^ 5887** 5888** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5889** Otherwise, an [error code] or an [extended error code] is returned.)^ 5890** ^Unless SQLITE_MISUSE is returned, this function sets the 5891** [database connection] error code and message accessible via 5892** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 5893** 5894** ^If the [BLOB handle] passed as the first argument was not opened for 5895** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5896** this function returns [SQLITE_READONLY]. 5897** 5898** This function may only modify the contents of the BLOB; it is 5899** not possible to increase the size of a BLOB using this API. 5900** ^If offset iOffset is less than N bytes from the end of the BLOB, 5901** [SQLITE_ERROR] is returned and no data is written. The size of the 5902** BLOB (and hence the maximum value of N+iOffset) can be determined 5903** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 5904** than zero [SQLITE_ERROR] is returned and no data is written. 5905** 5906** ^An attempt to write to an expired [BLOB handle] fails with an 5907** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5908** before the [BLOB handle] expired are not rolled back by the 5909** expiration of the handle, though of course those changes might 5910** have been overwritten by the statement that expired the BLOB handle 5911** or by other independent statements. 5912** 5913** This routine only works on a [BLOB handle] which has been created 5914** by a prior successful call to [sqlite3_blob_open()] and which has not 5915** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5916** to this routine results in undefined and probably undesirable behavior. 5917** 5918** See also: [sqlite3_blob_read()]. 5919*/ 5920SQLITE_API int SQLITE_STDCALL sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5921 5922/* 5923** CAPI3REF: Virtual File System Objects 5924** 5925** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5926** that SQLite uses to interact 5927** with the underlying operating system. Most SQLite builds come with a 5928** single default VFS that is appropriate for the host computer. 5929** New VFSes can be registered and existing VFSes can be unregistered. 5930** The following interfaces are provided. 5931** 5932** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5933** ^Names are case sensitive. 5934** ^Names are zero-terminated UTF-8 strings. 5935** ^If there is no match, a NULL pointer is returned. 5936** ^If zVfsName is NULL then the default VFS is returned. 5937** 5938** ^New VFSes are registered with sqlite3_vfs_register(). 5939** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5940** ^The same VFS can be registered multiple times without injury. 5941** ^To make an existing VFS into the default VFS, register it again 5942** with the makeDflt flag set. If two different VFSes with the 5943** same name are registered, the behavior is undefined. If a 5944** VFS is registered with a name that is NULL or an empty string, 5945** then the behavior is undefined. 5946** 5947** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5948** ^(If the default VFS is unregistered, another VFS is chosen as 5949** the default. The choice for the new VFS is arbitrary.)^ 5950*/ 5951SQLITE_API sqlite3_vfs *SQLITE_STDCALL sqlite3_vfs_find(const char *zVfsName); 5952SQLITE_API int SQLITE_STDCALL sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5953SQLITE_API int SQLITE_STDCALL sqlite3_vfs_unregister(sqlite3_vfs*); 5954 5955/* 5956** CAPI3REF: Mutexes 5957** 5958** The SQLite core uses these routines for thread 5959** synchronization. Though they are intended for internal 5960** use by SQLite, code that links against SQLite is 5961** permitted to use any of these routines. 5962** 5963** The SQLite source code contains multiple implementations 5964** of these mutex routines. An appropriate implementation 5965** is selected automatically at compile-time. The following 5966** implementations are available in the SQLite core: 5967** 5968** <ul> 5969** <li> SQLITE_MUTEX_PTHREADS 5970** <li> SQLITE_MUTEX_W32 5971** <li> SQLITE_MUTEX_NOOP 5972** </ul> 5973** 5974** The SQLITE_MUTEX_NOOP implementation is a set of routines 5975** that does no real locking and is appropriate for use in 5976** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 5977** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 5978** and Windows. 5979** 5980** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5981** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5982** implementation is included with the library. In this case the 5983** application must supply a custom mutex implementation using the 5984** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5985** before calling sqlite3_initialize() or any other public sqlite3_ 5986** function that calls sqlite3_initialize(). 5987** 5988** ^The sqlite3_mutex_alloc() routine allocates a new 5989** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 5990** routine returns NULL if it is unable to allocate the requested 5991** mutex. The argument to sqlite3_mutex_alloc() must one of these 5992** integer constants: 5993** 5994** <ul> 5995** <li> SQLITE_MUTEX_FAST 5996** <li> SQLITE_MUTEX_RECURSIVE 5997** <li> SQLITE_MUTEX_STATIC_MASTER 5998** <li> SQLITE_MUTEX_STATIC_MEM 5999** <li> SQLITE_MUTEX_STATIC_OPEN 6000** <li> SQLITE_MUTEX_STATIC_PRNG 6001** <li> SQLITE_MUTEX_STATIC_LRU 6002** <li> SQLITE_MUTEX_STATIC_PMEM 6003** <li> SQLITE_MUTEX_STATIC_APP1 6004** <li> SQLITE_MUTEX_STATIC_APP2 6005** <li> SQLITE_MUTEX_STATIC_APP3 6006** </ul> 6007** 6008** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6009** cause sqlite3_mutex_alloc() to create 6010** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6011** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6012** The mutex implementation does not need to make a distinction 6013** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6014** not want to. SQLite will only request a recursive mutex in 6015** cases where it really needs one. If a faster non-recursive mutex 6016** implementation is available on the host platform, the mutex subsystem 6017** might return such a mutex in response to SQLITE_MUTEX_FAST. 6018** 6019** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6020** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6021** a pointer to a static preexisting mutex. ^Nine static mutexes are 6022** used by the current version of SQLite. Future versions of SQLite 6023** may add additional static mutexes. Static mutexes are for internal 6024** use by SQLite only. Applications that use SQLite mutexes should 6025** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6026** SQLITE_MUTEX_RECURSIVE. 6027** 6028** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6029** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6030** returns a different mutex on every call. ^For the static 6031** mutex types, the same mutex is returned on every call that has 6032** the same type number. 6033** 6034** ^The sqlite3_mutex_free() routine deallocates a previously 6035** allocated dynamic mutex. Attempting to deallocate a static 6036** mutex results in undefined behavior. 6037** 6038** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6039** to enter a mutex. ^If another thread is already within the mutex, 6040** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6041** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6042** upon successful entry. ^(Mutexes created using 6043** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6044** In such cases, the 6045** mutex must be exited an equal number of times before another thread 6046** can enter.)^ If the same thread tries to enter any mutex other 6047** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6048** 6049** ^(Some systems (for example, Windows 95) do not support the operation 6050** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6051** will always return SQLITE_BUSY. The SQLite core only ever uses 6052** sqlite3_mutex_try() as an optimization so this is acceptable 6053** behavior.)^ 6054** 6055** ^The sqlite3_mutex_leave() routine exits a mutex that was 6056** previously entered by the same thread. The behavior 6057** is undefined if the mutex is not currently entered by the 6058** calling thread or is not currently allocated. 6059** 6060** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6061** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6062** behave as no-ops. 6063** 6064** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6065*/ 6066SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_mutex_alloc(int); 6067SQLITE_API void SQLITE_STDCALL sqlite3_mutex_free(sqlite3_mutex*); 6068SQLITE_API void SQLITE_STDCALL sqlite3_mutex_enter(sqlite3_mutex*); 6069SQLITE_API int SQLITE_STDCALL sqlite3_mutex_try(sqlite3_mutex*); 6070SQLITE_API void SQLITE_STDCALL sqlite3_mutex_leave(sqlite3_mutex*); 6071 6072/* 6073** CAPI3REF: Mutex Methods Object 6074** 6075** An instance of this structure defines the low-level routines 6076** used to allocate and use mutexes. 6077** 6078** Usually, the default mutex implementations provided by SQLite are 6079** sufficient, however the application has the option of substituting a custom 6080** implementation for specialized deployments or systems for which SQLite 6081** does not provide a suitable implementation. In this case, the application 6082** creates and populates an instance of this structure to pass 6083** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6084** Additionally, an instance of this structure can be used as an 6085** output variable when querying the system for the current mutex 6086** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6087** 6088** ^The xMutexInit method defined by this structure is invoked as 6089** part of system initialization by the sqlite3_initialize() function. 6090** ^The xMutexInit routine is called by SQLite exactly once for each 6091** effective call to [sqlite3_initialize()]. 6092** 6093** ^The xMutexEnd method defined by this structure is invoked as 6094** part of system shutdown by the sqlite3_shutdown() function. The 6095** implementation of this method is expected to release all outstanding 6096** resources obtained by the mutex methods implementation, especially 6097** those obtained by the xMutexInit method. ^The xMutexEnd() 6098** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6099** 6100** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6101** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6102** xMutexNotheld) implement the following interfaces (respectively): 6103** 6104** <ul> 6105** <li> [sqlite3_mutex_alloc()] </li> 6106** <li> [sqlite3_mutex_free()] </li> 6107** <li> [sqlite3_mutex_enter()] </li> 6108** <li> [sqlite3_mutex_try()] </li> 6109** <li> [sqlite3_mutex_leave()] </li> 6110** <li> [sqlite3_mutex_held()] </li> 6111** <li> [sqlite3_mutex_notheld()] </li> 6112** </ul>)^ 6113** 6114** The only difference is that the public sqlite3_XXX functions enumerated 6115** above silently ignore any invocations that pass a NULL pointer instead 6116** of a valid mutex handle. The implementations of the methods defined 6117** by this structure are not required to handle this case, the results 6118** of passing a NULL pointer instead of a valid mutex handle are undefined 6119** (i.e. it is acceptable to provide an implementation that segfaults if 6120** it is passed a NULL pointer). 6121** 6122** The xMutexInit() method must be threadsafe. It must be harmless to 6123** invoke xMutexInit() multiple times within the same process and without 6124** intervening calls to xMutexEnd(). Second and subsequent calls to 6125** xMutexInit() must be no-ops. 6126** 6127** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6128** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6129** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6130** memory allocation for a fast or recursive mutex. 6131** 6132** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6133** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6134** If xMutexInit fails in any way, it is expected to clean up after itself 6135** prior to returning. 6136*/ 6137typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6138struct sqlite3_mutex_methods { 6139 int (*xMutexInit)(void); 6140 int (*xMutexEnd)(void); 6141 sqlite3_mutex *(*xMutexAlloc)(int); 6142 void (*xMutexFree)(sqlite3_mutex *); 6143 void (*xMutexEnter)(sqlite3_mutex *); 6144 int (*xMutexTry)(sqlite3_mutex *); 6145 void (*xMutexLeave)(sqlite3_mutex *); 6146 int (*xMutexHeld)(sqlite3_mutex *); 6147 int (*xMutexNotheld)(sqlite3_mutex *); 6148}; 6149 6150/* 6151** CAPI3REF: Mutex Verification Routines 6152** 6153** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6154** are intended for use inside assert() statements. The SQLite core 6155** never uses these routines except inside an assert() and applications 6156** are advised to follow the lead of the core. The SQLite core only 6157** provides implementations for these routines when it is compiled 6158** with the SQLITE_DEBUG flag. External mutex implementations 6159** are only required to provide these routines if SQLITE_DEBUG is 6160** defined and if NDEBUG is not defined. 6161** 6162** These routines should return true if the mutex in their argument 6163** is held or not held, respectively, by the calling thread. 6164** 6165** The implementation is not required to provide versions of these 6166** routines that actually work. If the implementation does not provide working 6167** versions of these routines, it should at least provide stubs that always 6168** return true so that one does not get spurious assertion failures. 6169** 6170** If the argument to sqlite3_mutex_held() is a NULL pointer then 6171** the routine should return 1. This seems counter-intuitive since 6172** clearly the mutex cannot be held if it does not exist. But 6173** the reason the mutex does not exist is because the build is not 6174** using mutexes. And we do not want the assert() containing the 6175** call to sqlite3_mutex_held() to fail, so a non-zero return is 6176** the appropriate thing to do. The sqlite3_mutex_notheld() 6177** interface should also return 1 when given a NULL pointer. 6178*/ 6179#ifndef NDEBUG 6180SQLITE_API int SQLITE_STDCALL sqlite3_mutex_held(sqlite3_mutex*); 6181SQLITE_API int SQLITE_STDCALL sqlite3_mutex_notheld(sqlite3_mutex*); 6182#endif 6183 6184/* 6185** CAPI3REF: Mutex Types 6186** 6187** The [sqlite3_mutex_alloc()] interface takes a single argument 6188** which is one of these integer constants. 6189** 6190** The set of static mutexes may change from one SQLite release to the 6191** next. Applications that override the built-in mutex logic must be 6192** prepared to accommodate additional static mutexes. 6193*/ 6194#define SQLITE_MUTEX_FAST 0 6195#define SQLITE_MUTEX_RECURSIVE 1 6196#define SQLITE_MUTEX_STATIC_MASTER 2 6197#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6198#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6199#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6200#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 6201#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6202#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6203#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6204#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6205#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6206#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6207 6208/* 6209** CAPI3REF: Retrieve the mutex for a database connection 6210** 6211** ^This interface returns a pointer the [sqlite3_mutex] object that 6212** serializes access to the [database connection] given in the argument 6213** when the [threading mode] is Serialized. 6214** ^If the [threading mode] is Single-thread or Multi-thread then this 6215** routine returns a NULL pointer. 6216*/ 6217SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_db_mutex(sqlite3*); 6218 6219/* 6220** CAPI3REF: Low-Level Control Of Database Files 6221** 6222** ^The [sqlite3_file_control()] interface makes a direct call to the 6223** xFileControl method for the [sqlite3_io_methods] object associated 6224** with a particular database identified by the second argument. ^The 6225** name of the database is "main" for the main database or "temp" for the 6226** TEMP database, or the name that appears after the AS keyword for 6227** databases that are added using the [ATTACH] SQL command. 6228** ^A NULL pointer can be used in place of "main" to refer to the 6229** main database file. 6230** ^The third and fourth parameters to this routine 6231** are passed directly through to the second and third parameters of 6232** the xFileControl method. ^The return value of the xFileControl 6233** method becomes the return value of this routine. 6234** 6235** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6236** a pointer to the underlying [sqlite3_file] object to be written into 6237** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6238** case is a short-circuit path which does not actually invoke the 6239** underlying sqlite3_io_methods.xFileControl method. 6240** 6241** ^If the second parameter (zDbName) does not match the name of any 6242** open database file, then SQLITE_ERROR is returned. ^This error 6243** code is not remembered and will not be recalled by [sqlite3_errcode()] 6244** or [sqlite3_errmsg()]. The underlying xFileControl method might 6245** also return SQLITE_ERROR. There is no way to distinguish between 6246** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6247** xFileControl method. 6248** 6249** See also: [SQLITE_FCNTL_LOCKSTATE] 6250*/ 6251SQLITE_API int SQLITE_STDCALL sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6252 6253/* 6254** CAPI3REF: Testing Interface 6255** 6256** ^The sqlite3_test_control() interface is used to read out internal 6257** state of SQLite and to inject faults into SQLite for testing 6258** purposes. ^The first parameter is an operation code that determines 6259** the number, meaning, and operation of all subsequent parameters. 6260** 6261** This interface is not for use by applications. It exists solely 6262** for verifying the correct operation of the SQLite library. Depending 6263** on how the SQLite library is compiled, this interface might not exist. 6264** 6265** The details of the operation codes, their meanings, the parameters 6266** they take, and what they do are all subject to change without notice. 6267** Unlike most of the SQLite API, this function is not guaranteed to 6268** operate consistently from one release to the next. 6269*/ 6270SQLITE_API int SQLITE_CDECL sqlite3_test_control(int op, ...); 6271 6272/* 6273** CAPI3REF: Testing Interface Operation Codes 6274** 6275** These constants are the valid operation code parameters used 6276** as the first argument to [sqlite3_test_control()]. 6277** 6278** These parameters and their meanings are subject to change 6279** without notice. These values are for testing purposes only. 6280** Applications should not use any of these parameters or the 6281** [sqlite3_test_control()] interface. 6282*/ 6283#define SQLITE_TESTCTRL_FIRST 5 6284#define SQLITE_TESTCTRL_PRNG_SAVE 5 6285#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6286#define SQLITE_TESTCTRL_PRNG_RESET 7 6287#define SQLITE_TESTCTRL_BITVEC_TEST 8 6288#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6289#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6290#define SQLITE_TESTCTRL_PENDING_BYTE 11 6291#define SQLITE_TESTCTRL_ASSERT 12 6292#define SQLITE_TESTCTRL_ALWAYS 13 6293#define SQLITE_TESTCTRL_RESERVE 14 6294#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6295#define SQLITE_TESTCTRL_ISKEYWORD 16 6296#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6297#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6298#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6299#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6300#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6301#define SQLITE_TESTCTRL_BYTEORDER 22 6302#define SQLITE_TESTCTRL_ISINIT 23 6303#define SQLITE_TESTCTRL_SORTER_MMAP 24 6304#define SQLITE_TESTCTRL_IMPOSTER 25 6305#define SQLITE_TESTCTRL_LAST 25 6306 6307/* 6308** CAPI3REF: SQLite Runtime Status 6309** 6310** ^These interfaces are used to retrieve runtime status information 6311** about the performance of SQLite, and optionally to reset various 6312** highwater marks. ^The first argument is an integer code for 6313** the specific parameter to measure. ^(Recognized integer codes 6314** are of the form [status parameters | SQLITE_STATUS_...].)^ 6315** ^The current value of the parameter is returned into *pCurrent. 6316** ^The highest recorded value is returned in *pHighwater. ^If the 6317** resetFlag is true, then the highest record value is reset after 6318** *pHighwater is written. ^(Some parameters do not record the highest 6319** value. For those parameters 6320** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6321** ^(Other parameters record only the highwater mark and not the current 6322** value. For these latter parameters nothing is written into *pCurrent.)^ 6323** 6324** ^The sqlite3_status() and sqlite3_status64() routines return 6325** SQLITE_OK on success and a non-zero [error code] on failure. 6326** 6327** If either the current value or the highwater mark is too large to 6328** be represented by a 32-bit integer, then the values returned by 6329** sqlite3_status() are undefined. 6330** 6331** See also: [sqlite3_db_status()] 6332*/ 6333SQLITE_API int SQLITE_STDCALL sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6334SQLITE_API int SQLITE_STDCALL sqlite3_status64( 6335 int op, 6336 sqlite3_int64 *pCurrent, 6337 sqlite3_int64 *pHighwater, 6338 int resetFlag 6339); 6340 6341 6342/* 6343** CAPI3REF: Status Parameters 6344** KEYWORDS: {status parameters} 6345** 6346** These integer constants designate various run-time status parameters 6347** that can be returned by [sqlite3_status()]. 6348** 6349** <dl> 6350** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6351** <dd>This parameter is the current amount of memory checked out 6352** using [sqlite3_malloc()], either directly or indirectly. The 6353** figure includes calls made to [sqlite3_malloc()] by the application 6354** and internal memory usage by the SQLite library. Scratch memory 6355** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6356** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6357** this parameter. The amount returned is the sum of the allocation 6358** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6359** 6360** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6361** <dd>This parameter records the largest memory allocation request 6362** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6363** internal equivalents). Only the value returned in the 6364** *pHighwater parameter to [sqlite3_status()] is of interest. 6365** The value written into the *pCurrent parameter is undefined.</dd>)^ 6366** 6367** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6368** <dd>This parameter records the number of separate memory allocations 6369** currently checked out.</dd>)^ 6370** 6371** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6372** <dd>This parameter returns the number of pages used out of the 6373** [pagecache memory allocator] that was configured using 6374** [SQLITE_CONFIG_PAGECACHE]. The 6375** value returned is in pages, not in bytes.</dd>)^ 6376** 6377** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6378** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6379** <dd>This parameter returns the number of bytes of page cache 6380** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6381** buffer and where forced to overflow to [sqlite3_malloc()]. The 6382** returned value includes allocations that overflowed because they 6383** where too large (they were larger than the "sz" parameter to 6384** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6385** no space was left in the page cache.</dd>)^ 6386** 6387** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6388** <dd>This parameter records the largest memory allocation request 6389** handed to [pagecache memory allocator]. Only the value returned in the 6390** *pHighwater parameter to [sqlite3_status()] is of interest. 6391** The value written into the *pCurrent parameter is undefined.</dd>)^ 6392** 6393** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6394** <dd>This parameter returns the number of allocations used out of the 6395** [scratch memory allocator] configured using 6396** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6397** in bytes. Since a single thread may only have one scratch allocation 6398** outstanding at time, this parameter also reports the number of threads 6399** using scratch memory at the same time.</dd>)^ 6400** 6401** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6402** <dd>This parameter returns the number of bytes of scratch memory 6403** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6404** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6405** returned include overflows because the requested allocation was too 6406** larger (that is, because the requested allocation was larger than the 6407** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6408** slots were available. 6409** </dd>)^ 6410** 6411** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6412** <dd>This parameter records the largest memory allocation request 6413** handed to [scratch memory allocator]. Only the value returned in the 6414** *pHighwater parameter to [sqlite3_status()] is of interest. 6415** The value written into the *pCurrent parameter is undefined.</dd>)^ 6416** 6417** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6418** <dd>This parameter records the deepest parser stack. It is only 6419** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6420** </dl> 6421** 6422** New status parameters may be added from time to time. 6423*/ 6424#define SQLITE_STATUS_MEMORY_USED 0 6425#define SQLITE_STATUS_PAGECACHE_USED 1 6426#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6427#define SQLITE_STATUS_SCRATCH_USED 3 6428#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6429#define SQLITE_STATUS_MALLOC_SIZE 5 6430#define SQLITE_STATUS_PARSER_STACK 6 6431#define SQLITE_STATUS_PAGECACHE_SIZE 7 6432#define SQLITE_STATUS_SCRATCH_SIZE 8 6433#define SQLITE_STATUS_MALLOC_COUNT 9 6434 6435/* 6436** CAPI3REF: Database Connection Status 6437** 6438** ^This interface is used to retrieve runtime status information 6439** about a single [database connection]. ^The first argument is the 6440** database connection object to be interrogated. ^The second argument 6441** is an integer constant, taken from the set of 6442** [SQLITE_DBSTATUS options], that 6443** determines the parameter to interrogate. The set of 6444** [SQLITE_DBSTATUS options] is likely 6445** to grow in future releases of SQLite. 6446** 6447** ^The current value of the requested parameter is written into *pCur 6448** and the highest instantaneous value is written into *pHiwtr. ^If 6449** the resetFlg is true, then the highest instantaneous value is 6450** reset back down to the current value. 6451** 6452** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6453** non-zero [error code] on failure. 6454** 6455** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6456*/ 6457SQLITE_API int SQLITE_STDCALL sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6458 6459/* 6460** CAPI3REF: Status Parameters for database connections 6461** KEYWORDS: {SQLITE_DBSTATUS options} 6462** 6463** These constants are the available integer "verbs" that can be passed as 6464** the second argument to the [sqlite3_db_status()] interface. 6465** 6466** New verbs may be added in future releases of SQLite. Existing verbs 6467** might be discontinued. Applications should check the return code from 6468** [sqlite3_db_status()] to make sure that the call worked. 6469** The [sqlite3_db_status()] interface will return a non-zero error code 6470** if a discontinued or unsupported verb is invoked. 6471** 6472** <dl> 6473** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6474** <dd>This parameter returns the number of lookaside memory slots currently 6475** checked out.</dd>)^ 6476** 6477** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6478** <dd>This parameter returns the number malloc attempts that were 6479** satisfied using lookaside memory. Only the high-water value is meaningful; 6480** the current value is always zero.)^ 6481** 6482** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6483** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6484** <dd>This parameter returns the number malloc attempts that might have 6485** been satisfied using lookaside memory but failed due to the amount of 6486** memory requested being larger than the lookaside slot size. 6487** Only the high-water value is meaningful; 6488** the current value is always zero.)^ 6489** 6490** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6491** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6492** <dd>This parameter returns the number malloc attempts that might have 6493** been satisfied using lookaside memory but failed due to all lookaside 6494** memory already being in use. 6495** Only the high-water value is meaningful; 6496** the current value is always zero.)^ 6497** 6498** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6499** <dd>This parameter returns the approximate number of bytes of heap 6500** memory used by all pager caches associated with the database connection.)^ 6501** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6502** 6503** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6504** <dd>This parameter returns the approximate number of bytes of heap 6505** memory used to store the schema for all databases associated 6506** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6507** ^The full amount of memory used by the schemas is reported, even if the 6508** schema memory is shared with other database connections due to 6509** [shared cache mode] being enabled. 6510** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6511** 6512** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6513** <dd>This parameter returns the approximate number of bytes of heap 6514** and lookaside memory used by all prepared statements associated with 6515** the database connection.)^ 6516** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6517** </dd> 6518** 6519** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6520** <dd>This parameter returns the number of pager cache hits that have 6521** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6522** is always 0. 6523** </dd> 6524** 6525** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6526** <dd>This parameter returns the number of pager cache misses that have 6527** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6528** is always 0. 6529** </dd> 6530** 6531** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6532** <dd>This parameter returns the number of dirty cache entries that have 6533** been written to disk. Specifically, the number of pages written to the 6534** wal file in wal mode databases, or the number of pages written to the 6535** database file in rollback mode databases. Any pages written as part of 6536** transaction rollback or database recovery operations are not included. 6537** If an IO or other error occurs while writing a page to disk, the effect 6538** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6539** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6540** </dd> 6541** 6542** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 6543** <dd>This parameter returns zero for the current value if and only if 6544** all foreign key constraints (deferred or immediate) have been 6545** resolved.)^ ^The highwater mark is always 0. 6546** </dd> 6547** </dl> 6548*/ 6549#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6550#define SQLITE_DBSTATUS_CACHE_USED 1 6551#define SQLITE_DBSTATUS_SCHEMA_USED 2 6552#define SQLITE_DBSTATUS_STMT_USED 3 6553#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6554#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6555#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6556#define SQLITE_DBSTATUS_CACHE_HIT 7 6557#define SQLITE_DBSTATUS_CACHE_MISS 8 6558#define SQLITE_DBSTATUS_CACHE_WRITE 9 6559#define SQLITE_DBSTATUS_DEFERRED_FKS 10 6560#define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */ 6561 6562 6563/* 6564** CAPI3REF: Prepared Statement Status 6565** 6566** ^(Each prepared statement maintains various 6567** [SQLITE_STMTSTATUS counters] that measure the number 6568** of times it has performed specific operations.)^ These counters can 6569** be used to monitor the performance characteristics of the prepared 6570** statements. For example, if the number of table steps greatly exceeds 6571** the number of table searches or result rows, that would tend to indicate 6572** that the prepared statement is using a full table scan rather than 6573** an index. 6574** 6575** ^(This interface is used to retrieve and reset counter values from 6576** a [prepared statement]. The first argument is the prepared statement 6577** object to be interrogated. The second argument 6578** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6579** to be interrogated.)^ 6580** ^The current value of the requested counter is returned. 6581** ^If the resetFlg is true, then the counter is reset to zero after this 6582** interface call returns. 6583** 6584** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6585*/ 6586SQLITE_API int SQLITE_STDCALL sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6587 6588/* 6589** CAPI3REF: Status Parameters for prepared statements 6590** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6591** 6592** These preprocessor macros define integer codes that name counter 6593** values associated with the [sqlite3_stmt_status()] interface. 6594** The meanings of the various counters are as follows: 6595** 6596** <dl> 6597** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6598** <dd>^This is the number of times that SQLite has stepped forward in 6599** a table as part of a full table scan. Large numbers for this counter 6600** may indicate opportunities for performance improvement through 6601** careful use of indices.</dd> 6602** 6603** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6604** <dd>^This is the number of sort operations that have occurred. 6605** A non-zero value in this counter may indicate an opportunity to 6606** improvement performance through careful use of indices.</dd> 6607** 6608** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6609** <dd>^This is the number of rows inserted into transient indices that 6610** were created automatically in order to help joins run faster. 6611** A non-zero value in this counter may indicate an opportunity to 6612** improvement performance by adding permanent indices that do not 6613** need to be reinitialized each time the statement is run.</dd> 6614** 6615** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 6616** <dd>^This is the number of virtual machine operations executed 6617** by the prepared statement if that number is less than or equal 6618** to 2147483647. The number of virtual machine operations can be 6619** used as a proxy for the total work done by the prepared statement. 6620** If the number of virtual machine operations exceeds 2147483647 6621** then the value returned by this statement status code is undefined. 6622** </dd> 6623** </dl> 6624*/ 6625#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6626#define SQLITE_STMTSTATUS_SORT 2 6627#define SQLITE_STMTSTATUS_AUTOINDEX 3 6628#define SQLITE_STMTSTATUS_VM_STEP 4 6629 6630/* 6631** CAPI3REF: Custom Page Cache Object 6632** 6633** The sqlite3_pcache type is opaque. It is implemented by 6634** the pluggable module. The SQLite core has no knowledge of 6635** its size or internal structure and never deals with the 6636** sqlite3_pcache object except by holding and passing pointers 6637** to the object. 6638** 6639** See [sqlite3_pcache_methods2] for additional information. 6640*/ 6641typedef struct sqlite3_pcache sqlite3_pcache; 6642 6643/* 6644** CAPI3REF: Custom Page Cache Object 6645** 6646** The sqlite3_pcache_page object represents a single page in the 6647** page cache. The page cache will allocate instances of this 6648** object. Various methods of the page cache use pointers to instances 6649** of this object as parameters or as their return value. 6650** 6651** See [sqlite3_pcache_methods2] for additional information. 6652*/ 6653typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6654struct sqlite3_pcache_page { 6655 void *pBuf; /* The content of the page */ 6656 void *pExtra; /* Extra information associated with the page */ 6657}; 6658 6659/* 6660** CAPI3REF: Application Defined Page Cache. 6661** KEYWORDS: {page cache} 6662** 6663** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6664** register an alternative page cache implementation by passing in an 6665** instance of the sqlite3_pcache_methods2 structure.)^ 6666** In many applications, most of the heap memory allocated by 6667** SQLite is used for the page cache. 6668** By implementing a 6669** custom page cache using this API, an application can better control 6670** the amount of memory consumed by SQLite, the way in which 6671** that memory is allocated and released, and the policies used to 6672** determine exactly which parts of a database file are cached and for 6673** how long. 6674** 6675** The alternative page cache mechanism is an 6676** extreme measure that is only needed by the most demanding applications. 6677** The built-in page cache is recommended for most uses. 6678** 6679** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6680** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6681** the application may discard the parameter after the call to 6682** [sqlite3_config()] returns.)^ 6683** 6684** [[the xInit() page cache method]] 6685** ^(The xInit() method is called once for each effective 6686** call to [sqlite3_initialize()])^ 6687** (usually only once during the lifetime of the process). ^(The xInit() 6688** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6689** The intent of the xInit() method is to set up global data structures 6690** required by the custom page cache implementation. 6691** ^(If the xInit() method is NULL, then the 6692** built-in default page cache is used instead of the application defined 6693** page cache.)^ 6694** 6695** [[the xShutdown() page cache method]] 6696** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6697** It can be used to clean up 6698** any outstanding resources before process shutdown, if required. 6699** ^The xShutdown() method may be NULL. 6700** 6701** ^SQLite automatically serializes calls to the xInit method, 6702** so the xInit method need not be threadsafe. ^The 6703** xShutdown method is only called from [sqlite3_shutdown()] so it does 6704** not need to be threadsafe either. All other methods must be threadsafe 6705** in multithreaded applications. 6706** 6707** ^SQLite will never invoke xInit() more than once without an intervening 6708** call to xShutdown(). 6709** 6710** [[the xCreate() page cache methods]] 6711** ^SQLite invokes the xCreate() method to construct a new cache instance. 6712** SQLite will typically create one cache instance for each open database file, 6713** though this is not guaranteed. ^The 6714** first parameter, szPage, is the size in bytes of the pages that must 6715** be allocated by the cache. ^szPage will always a power of two. ^The 6716** second parameter szExtra is a number of bytes of extra storage 6717** associated with each page cache entry. ^The szExtra parameter will 6718** a number less than 250. SQLite will use the 6719** extra szExtra bytes on each page to store metadata about the underlying 6720** database page on disk. The value passed into szExtra depends 6721** on the SQLite version, the target platform, and how SQLite was compiled. 6722** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6723** created will be used to cache database pages of a file stored on disk, or 6724** false if it is used for an in-memory database. The cache implementation 6725** does not have to do anything special based with the value of bPurgeable; 6726** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6727** never invoke xUnpin() except to deliberately delete a page. 6728** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6729** false will always have the "discard" flag set to true. 6730** ^Hence, a cache created with bPurgeable false will 6731** never contain any unpinned pages. 6732** 6733** [[the xCachesize() page cache method]] 6734** ^(The xCachesize() method may be called at any time by SQLite to set the 6735** suggested maximum cache-size (number of pages stored by) the cache 6736** instance passed as the first argument. This is the value configured using 6737** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6738** parameter, the implementation is not required to do anything with this 6739** value; it is advisory only. 6740** 6741** [[the xPagecount() page cache methods]] 6742** The xPagecount() method must return the number of pages currently 6743** stored in the cache, both pinned and unpinned. 6744** 6745** [[the xFetch() page cache methods]] 6746** The xFetch() method locates a page in the cache and returns a pointer to 6747** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6748** The pBuf element of the returned sqlite3_pcache_page object will be a 6749** pointer to a buffer of szPage bytes used to store the content of a 6750** single database page. The pExtra element of sqlite3_pcache_page will be 6751** a pointer to the szExtra bytes of extra storage that SQLite has requested 6752** for each entry in the page cache. 6753** 6754** The page to be fetched is determined by the key. ^The minimum key value 6755** is 1. After it has been retrieved using xFetch, the page is considered 6756** to be "pinned". 6757** 6758** If the requested page is already in the page cache, then the page cache 6759** implementation must return a pointer to the page buffer with its content 6760** intact. If the requested page is not already in the cache, then the 6761** cache implementation should use the value of the createFlag 6762** parameter to help it determined what action to take: 6763** 6764** <table border=1 width=85% align=center> 6765** <tr><th> createFlag <th> Behavior when page is not already in cache 6766** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6767** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6768** Otherwise return NULL. 6769** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6770** NULL if allocating a new page is effectively impossible. 6771** </table> 6772** 6773** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6774** will only use a createFlag of 2 after a prior call with a createFlag of 1 6775** failed.)^ In between the to xFetch() calls, SQLite may 6776** attempt to unpin one or more cache pages by spilling the content of 6777** pinned pages to disk and synching the operating system disk cache. 6778** 6779** [[the xUnpin() page cache method]] 6780** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6781** as its second argument. If the third parameter, discard, is non-zero, 6782** then the page must be evicted from the cache. 6783** ^If the discard parameter is 6784** zero, then the page may be discarded or retained at the discretion of 6785** page cache implementation. ^The page cache implementation 6786** may choose to evict unpinned pages at any time. 6787** 6788** The cache must not perform any reference counting. A single 6789** call to xUnpin() unpins the page regardless of the number of prior calls 6790** to xFetch(). 6791** 6792** [[the xRekey() page cache methods]] 6793** The xRekey() method is used to change the key value associated with the 6794** page passed as the second argument. If the cache 6795** previously contains an entry associated with newKey, it must be 6796** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6797** to be pinned. 6798** 6799** When SQLite calls the xTruncate() method, the cache must discard all 6800** existing cache entries with page numbers (keys) greater than or equal 6801** to the value of the iLimit parameter passed to xTruncate(). If any 6802** of these pages are pinned, they are implicitly unpinned, meaning that 6803** they can be safely discarded. 6804** 6805** [[the xDestroy() page cache method]] 6806** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6807** All resources associated with the specified cache should be freed. ^After 6808** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6809** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6810** functions. 6811** 6812** [[the xShrink() page cache method]] 6813** ^SQLite invokes the xShrink() method when it wants the page cache to 6814** free up as much of heap memory as possible. The page cache implementation 6815** is not obligated to free any memory, but well-behaved implementations should 6816** do their best. 6817*/ 6818typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6819struct sqlite3_pcache_methods2 { 6820 int iVersion; 6821 void *pArg; 6822 int (*xInit)(void*); 6823 void (*xShutdown)(void*); 6824 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6825 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6826 int (*xPagecount)(sqlite3_pcache*); 6827 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6828 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6829 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6830 unsigned oldKey, unsigned newKey); 6831 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6832 void (*xDestroy)(sqlite3_pcache*); 6833 void (*xShrink)(sqlite3_pcache*); 6834}; 6835 6836/* 6837** This is the obsolete pcache_methods object that has now been replaced 6838** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6839** retained in the header file for backwards compatibility only. 6840*/ 6841typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6842struct sqlite3_pcache_methods { 6843 void *pArg; 6844 int (*xInit)(void*); 6845 void (*xShutdown)(void*); 6846 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6847 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6848 int (*xPagecount)(sqlite3_pcache*); 6849 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6850 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6851 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6852 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6853 void (*xDestroy)(sqlite3_pcache*); 6854}; 6855 6856 6857/* 6858** CAPI3REF: Online Backup Object 6859** 6860** The sqlite3_backup object records state information about an ongoing 6861** online backup operation. ^The sqlite3_backup object is created by 6862** a call to [sqlite3_backup_init()] and is destroyed by a call to 6863** [sqlite3_backup_finish()]. 6864** 6865** See Also: [Using the SQLite Online Backup API] 6866*/ 6867typedef struct sqlite3_backup sqlite3_backup; 6868 6869/* 6870** CAPI3REF: Online Backup API. 6871** 6872** The backup API copies the content of one database into another. 6873** It is useful either for creating backups of databases or 6874** for copying in-memory databases to or from persistent files. 6875** 6876** See Also: [Using the SQLite Online Backup API] 6877** 6878** ^SQLite holds a write transaction open on the destination database file 6879** for the duration of the backup operation. 6880** ^The source database is read-locked only while it is being read; 6881** it is not locked continuously for the entire backup operation. 6882** ^Thus, the backup may be performed on a live source database without 6883** preventing other database connections from 6884** reading or writing to the source database while the backup is underway. 6885** 6886** ^(To perform a backup operation: 6887** <ol> 6888** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6889** backup, 6890** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6891** the data between the two databases, and finally 6892** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6893** associated with the backup operation. 6894** </ol>)^ 6895** There should be exactly one call to sqlite3_backup_finish() for each 6896** successful call to sqlite3_backup_init(). 6897** 6898** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6899** 6900** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6901** [database connection] associated with the destination database 6902** and the database name, respectively. 6903** ^The database name is "main" for the main database, "temp" for the 6904** temporary database, or the name specified after the AS keyword in 6905** an [ATTACH] statement for an attached database. 6906** ^The S and M arguments passed to 6907** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6908** and database name of the source database, respectively. 6909** ^The source and destination [database connections] (parameters S and D) 6910** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6911** an error. 6912** 6913** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if 6914** there is already a read or read-write transaction open on the 6915** destination database. 6916** 6917** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6918** returned and an error code and error message are stored in the 6919** destination [database connection] D. 6920** ^The error code and message for the failed call to sqlite3_backup_init() 6921** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6922** [sqlite3_errmsg16()] functions. 6923** ^A successful call to sqlite3_backup_init() returns a pointer to an 6924** [sqlite3_backup] object. 6925** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6926** sqlite3_backup_finish() functions to perform the specified backup 6927** operation. 6928** 6929** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6930** 6931** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6932** the source and destination databases specified by [sqlite3_backup] object B. 6933** ^If N is negative, all remaining source pages are copied. 6934** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6935** are still more pages to be copied, then the function returns [SQLITE_OK]. 6936** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6937** from source to destination, then it returns [SQLITE_DONE]. 6938** ^If an error occurs while running sqlite3_backup_step(B,N), 6939** then an [error code] is returned. ^As well as [SQLITE_OK] and 6940** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6941** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6942** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6943** 6944** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6945** <ol> 6946** <li> the destination database was opened read-only, or 6947** <li> the destination database is using write-ahead-log journaling 6948** and the destination and source page sizes differ, or 6949** <li> the destination database is an in-memory database and the 6950** destination and source page sizes differ. 6951** </ol>)^ 6952** 6953** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6954** the [sqlite3_busy_handler | busy-handler function] 6955** is invoked (if one is specified). ^If the 6956** busy-handler returns non-zero before the lock is available, then 6957** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6958** sqlite3_backup_step() can be retried later. ^If the source 6959** [database connection] 6960** is being used to write to the source database when sqlite3_backup_step() 6961** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6962** case the call to sqlite3_backup_step() can be retried later on. ^(If 6963** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6964** [SQLITE_READONLY] is returned, then 6965** there is no point in retrying the call to sqlite3_backup_step(). These 6966** errors are considered fatal.)^ The application must accept 6967** that the backup operation has failed and pass the backup operation handle 6968** to the sqlite3_backup_finish() to release associated resources. 6969** 6970** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6971** on the destination file. ^The exclusive lock is not released until either 6972** sqlite3_backup_finish() is called or the backup operation is complete 6973** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6974** sqlite3_backup_step() obtains a [shared lock] on the source database that 6975** lasts for the duration of the sqlite3_backup_step() call. 6976** ^Because the source database is not locked between calls to 6977** sqlite3_backup_step(), the source database may be modified mid-way 6978** through the backup process. ^If the source database is modified by an 6979** external process or via a database connection other than the one being 6980** used by the backup operation, then the backup will be automatically 6981** restarted by the next call to sqlite3_backup_step(). ^If the source 6982** database is modified by the using the same database connection as is used 6983** by the backup operation, then the backup database is automatically 6984** updated at the same time. 6985** 6986** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6987** 6988** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6989** application wishes to abandon the backup operation, the application 6990** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6991** ^The sqlite3_backup_finish() interfaces releases all 6992** resources associated with the [sqlite3_backup] object. 6993** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6994** active write-transaction on the destination database is rolled back. 6995** The [sqlite3_backup] object is invalid 6996** and may not be used following a call to sqlite3_backup_finish(). 6997** 6998** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6999** sqlite3_backup_step() errors occurred, regardless or whether or not 7000** sqlite3_backup_step() completed. 7001** ^If an out-of-memory condition or IO error occurred during any prior 7002** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7003** sqlite3_backup_finish() returns the corresponding [error code]. 7004** 7005** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7006** is not a permanent error and does not affect the return value of 7007** sqlite3_backup_finish(). 7008** 7009** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7010** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7011** 7012** ^The sqlite3_backup_remaining() routine returns the number of pages still 7013** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7014** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7015** in the source database at the conclusion of the most recent 7016** sqlite3_backup_step(). 7017** ^(The values returned by these functions are only updated by 7018** sqlite3_backup_step(). If the source database is modified in a way that 7019** changes the size of the source database or the number of pages remaining, 7020** those changes are not reflected in the output of sqlite3_backup_pagecount() 7021** and sqlite3_backup_remaining() until after the next 7022** sqlite3_backup_step().)^ 7023** 7024** <b>Concurrent Usage of Database Handles</b> 7025** 7026** ^The source [database connection] may be used by the application for other 7027** purposes while a backup operation is underway or being initialized. 7028** ^If SQLite is compiled and configured to support threadsafe database 7029** connections, then the source database connection may be used concurrently 7030** from within other threads. 7031** 7032** However, the application must guarantee that the destination 7033** [database connection] is not passed to any other API (by any thread) after 7034** sqlite3_backup_init() is called and before the corresponding call to 7035** sqlite3_backup_finish(). SQLite does not currently check to see 7036** if the application incorrectly accesses the destination [database connection] 7037** and so no error code is reported, but the operations may malfunction 7038** nevertheless. Use of the destination database connection while a 7039** backup is in progress might also also cause a mutex deadlock. 7040** 7041** If running in [shared cache mode], the application must 7042** guarantee that the shared cache used by the destination database 7043** is not accessed while the backup is running. In practice this means 7044** that the application must guarantee that the disk file being 7045** backed up to is not accessed by any connection within the process, 7046** not just the specific connection that was passed to sqlite3_backup_init(). 7047** 7048** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7049** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7050** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7051** APIs are not strictly speaking threadsafe. If they are invoked at the 7052** same time as another thread is invoking sqlite3_backup_step() it is 7053** possible that they return invalid values. 7054*/ 7055SQLITE_API sqlite3_backup *SQLITE_STDCALL sqlite3_backup_init( 7056 sqlite3 *pDest, /* Destination database handle */ 7057 const char *zDestName, /* Destination database name */ 7058 sqlite3 *pSource, /* Source database handle */ 7059 const char *zSourceName /* Source database name */ 7060); 7061SQLITE_API int SQLITE_STDCALL sqlite3_backup_step(sqlite3_backup *p, int nPage); 7062SQLITE_API int SQLITE_STDCALL sqlite3_backup_finish(sqlite3_backup *p); 7063SQLITE_API int SQLITE_STDCALL sqlite3_backup_remaining(sqlite3_backup *p); 7064SQLITE_API int SQLITE_STDCALL sqlite3_backup_pagecount(sqlite3_backup *p); 7065 7066/* 7067** CAPI3REF: Unlock Notification 7068** 7069** ^When running in shared-cache mode, a database operation may fail with 7070** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7071** individual tables within the shared-cache cannot be obtained. See 7072** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7073** ^This API may be used to register a callback that SQLite will invoke 7074** when the connection currently holding the required lock relinquishes it. 7075** ^This API is only available if the library was compiled with the 7076** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7077** 7078** See Also: [Using the SQLite Unlock Notification Feature]. 7079** 7080** ^Shared-cache locks are released when a database connection concludes 7081** its current transaction, either by committing it or rolling it back. 7082** 7083** ^When a connection (known as the blocked connection) fails to obtain a 7084** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7085** identity of the database connection (the blocking connection) that 7086** has locked the required resource is stored internally. ^After an 7087** application receives an SQLITE_LOCKED error, it may call the 7088** sqlite3_unlock_notify() method with the blocked connection handle as 7089** the first argument to register for a callback that will be invoked 7090** when the blocking connections current transaction is concluded. ^The 7091** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7092** call that concludes the blocking connections transaction. 7093** 7094** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7095** there is a chance that the blocking connection will have already 7096** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7097** If this happens, then the specified callback is invoked immediately, 7098** from within the call to sqlite3_unlock_notify().)^ 7099** 7100** ^If the blocked connection is attempting to obtain a write-lock on a 7101** shared-cache table, and more than one other connection currently holds 7102** a read-lock on the same table, then SQLite arbitrarily selects one of 7103** the other connections to use as the blocking connection. 7104** 7105** ^(There may be at most one unlock-notify callback registered by a 7106** blocked connection. If sqlite3_unlock_notify() is called when the 7107** blocked connection already has a registered unlock-notify callback, 7108** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7109** called with a NULL pointer as its second argument, then any existing 7110** unlock-notify callback is canceled. ^The blocked connections 7111** unlock-notify callback may also be canceled by closing the blocked 7112** connection using [sqlite3_close()]. 7113** 7114** The unlock-notify callback is not reentrant. If an application invokes 7115** any sqlite3_xxx API functions from within an unlock-notify callback, a 7116** crash or deadlock may be the result. 7117** 7118** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7119** returns SQLITE_OK. 7120** 7121** <b>Callback Invocation Details</b> 7122** 7123** When an unlock-notify callback is registered, the application provides a 7124** single void* pointer that is passed to the callback when it is invoked. 7125** However, the signature of the callback function allows SQLite to pass 7126** it an array of void* context pointers. The first argument passed to 7127** an unlock-notify callback is a pointer to an array of void* pointers, 7128** and the second is the number of entries in the array. 7129** 7130** When a blocking connections transaction is concluded, there may be 7131** more than one blocked connection that has registered for an unlock-notify 7132** callback. ^If two or more such blocked connections have specified the 7133** same callback function, then instead of invoking the callback function 7134** multiple times, it is invoked once with the set of void* context pointers 7135** specified by the blocked connections bundled together into an array. 7136** This gives the application an opportunity to prioritize any actions 7137** related to the set of unblocked database connections. 7138** 7139** <b>Deadlock Detection</b> 7140** 7141** Assuming that after registering for an unlock-notify callback a 7142** database waits for the callback to be issued before taking any further 7143** action (a reasonable assumption), then using this API may cause the 7144** application to deadlock. For example, if connection X is waiting for 7145** connection Y's transaction to be concluded, and similarly connection 7146** Y is waiting on connection X's transaction, then neither connection 7147** will proceed and the system may remain deadlocked indefinitely. 7148** 7149** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7150** detection. ^If a given call to sqlite3_unlock_notify() would put the 7151** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7152** unlock-notify callback is registered. The system is said to be in 7153** a deadlocked state if connection A has registered for an unlock-notify 7154** callback on the conclusion of connection B's transaction, and connection 7155** B has itself registered for an unlock-notify callback when connection 7156** A's transaction is concluded. ^Indirect deadlock is also detected, so 7157** the system is also considered to be deadlocked if connection B has 7158** registered for an unlock-notify callback on the conclusion of connection 7159** C's transaction, where connection C is waiting on connection A. ^Any 7160** number of levels of indirection are allowed. 7161** 7162** <b>The "DROP TABLE" Exception</b> 7163** 7164** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7165** always appropriate to call sqlite3_unlock_notify(). There is however, 7166** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7167** SQLite checks if there are any currently executing SELECT statements 7168** that belong to the same connection. If there are, SQLITE_LOCKED is 7169** returned. In this case there is no "blocking connection", so invoking 7170** sqlite3_unlock_notify() results in the unlock-notify callback being 7171** invoked immediately. If the application then re-attempts the "DROP TABLE" 7172** or "DROP INDEX" query, an infinite loop might be the result. 7173** 7174** One way around this problem is to check the extended error code returned 7175** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7176** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7177** the special "DROP TABLE/INDEX" case, the extended error code is just 7178** SQLITE_LOCKED.)^ 7179*/ 7180SQLITE_API int SQLITE_STDCALL sqlite3_unlock_notify( 7181 sqlite3 *pBlocked, /* Waiting connection */ 7182 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7183 void *pNotifyArg /* Argument to pass to xNotify */ 7184); 7185 7186 7187/* 7188** CAPI3REF: String Comparison 7189** 7190** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7191** and extensions to compare the contents of two buffers containing UTF-8 7192** strings in a case-independent fashion, using the same definition of "case 7193** independence" that SQLite uses internally when comparing identifiers. 7194*/ 7195SQLITE_API int SQLITE_STDCALL sqlite3_stricmp(const char *, const char *); 7196SQLITE_API int SQLITE_STDCALL sqlite3_strnicmp(const char *, const char *, int); 7197 7198/* 7199** CAPI3REF: String Globbing 7200* 7201** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches 7202** the glob pattern P, and it returns non-zero if string X does not match 7203** the glob pattern P. ^The definition of glob pattern matching used in 7204** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7205** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case 7206** sensitive. 7207** 7208** Note that this routine returns zero on a match and non-zero if the strings 7209** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7210*/ 7211SQLITE_API int SQLITE_STDCALL sqlite3_strglob(const char *zGlob, const char *zStr); 7212 7213/* 7214** CAPI3REF: Error Logging Interface 7215** 7216** ^The [sqlite3_log()] interface writes a message into the [error log] 7217** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7218** ^If logging is enabled, the zFormat string and subsequent arguments are 7219** used with [sqlite3_snprintf()] to generate the final output string. 7220** 7221** The sqlite3_log() interface is intended for use by extensions such as 7222** virtual tables, collating functions, and SQL functions. While there is 7223** nothing to prevent an application from calling sqlite3_log(), doing so 7224** is considered bad form. 7225** 7226** The zFormat string must not be NULL. 7227** 7228** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7229** will not use dynamically allocated memory. The log message is stored in 7230** a fixed-length buffer on the stack. If the log message is longer than 7231** a few hundred characters, it will be truncated to the length of the 7232** buffer. 7233*/ 7234SQLITE_API void SQLITE_CDECL sqlite3_log(int iErrCode, const char *zFormat, ...); 7235 7236/* 7237** CAPI3REF: Write-Ahead Log Commit Hook 7238** 7239** ^The [sqlite3_wal_hook()] function is used to register a callback that 7240** is invoked each time data is committed to a database in wal mode. 7241** 7242** ^(The callback is invoked by SQLite after the commit has taken place and 7243** the associated write-lock on the database released)^, so the implementation 7244** may read, write or [checkpoint] the database as required. 7245** 7246** ^The first parameter passed to the callback function when it is invoked 7247** is a copy of the third parameter passed to sqlite3_wal_hook() when 7248** registering the callback. ^The second is a copy of the database handle. 7249** ^The third parameter is the name of the database that was written to - 7250** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7251** is the number of pages currently in the write-ahead log file, 7252** including those that were just committed. 7253** 7254** The callback function should normally return [SQLITE_OK]. ^If an error 7255** code is returned, that error will propagate back up through the 7256** SQLite code base to cause the statement that provoked the callback 7257** to report an error, though the commit will have still occurred. If the 7258** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7259** that does not correspond to any valid SQLite error code, the results 7260** are undefined. 7261** 7262** A single database handle may have at most a single write-ahead log callback 7263** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7264** previously registered write-ahead log callback. ^Note that the 7265** [sqlite3_wal_autocheckpoint()] interface and the 7266** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7267** those overwrite any prior [sqlite3_wal_hook()] settings. 7268*/ 7269SQLITE_API void *SQLITE_STDCALL sqlite3_wal_hook( 7270 sqlite3*, 7271 int(*)(void *,sqlite3*,const char*,int), 7272 void* 7273); 7274 7275/* 7276** CAPI3REF: Configure an auto-checkpoint 7277** 7278** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 7279** [sqlite3_wal_hook()] that causes any database on [database connection] D 7280** to automatically [checkpoint] 7281** after committing a transaction if there are N or 7282** more frames in the [write-ahead log] file. ^Passing zero or 7283** a negative value as the nFrame parameter disables automatic 7284** checkpoints entirely. 7285** 7286** ^The callback registered by this function replaces any existing callback 7287** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 7288** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 7289** configured by this function. 7290** 7291** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 7292** from SQL. 7293** 7294** ^Checkpoints initiated by this mechanism are 7295** [sqlite3_wal_checkpoint_v2|PASSIVE]. 7296** 7297** ^Every new [database connection] defaults to having the auto-checkpoint 7298** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 7299** pages. The use of this interface 7300** is only necessary if the default setting is found to be suboptimal 7301** for a particular application. 7302*/ 7303SQLITE_API int SQLITE_STDCALL sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 7304 7305/* 7306** CAPI3REF: Checkpoint a database 7307** 7308** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 7309** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 7310** 7311** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 7312** [write-ahead log] for database X on [database connection] D to be 7313** transferred into the database file and for the write-ahead log to 7314** be reset. See the [checkpointing] documentation for addition 7315** information. 7316** 7317** This interface used to be the only way to cause a checkpoint to 7318** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 7319** interface was added. This interface is retained for backwards 7320** compatibility and as a convenience for applications that need to manually 7321** start a callback but which do not need the full power (and corresponding 7322** complication) of [sqlite3_wal_checkpoint_v2()]. 7323*/ 7324SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 7325 7326/* 7327** CAPI3REF: Checkpoint a database 7328** 7329** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 7330** operation on database X of [database connection] D in mode M. Status 7331** information is written back into integers pointed to by L and C.)^ 7332** ^(The M parameter must be a valid [checkpoint mode]:)^ 7333** 7334** <dl> 7335** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7336** ^Checkpoint as many frames as possible without waiting for any database 7337** readers or writers to finish, then sync the database file if all frames 7338** in the log were checkpointed. ^The [busy-handler callback] 7339** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 7340** ^On the other hand, passive mode might leave the checkpoint unfinished 7341** if there are concurrent readers or writers. 7342** 7343** <dt>SQLITE_CHECKPOINT_FULL<dd> 7344** ^This mode blocks (it invokes the 7345** [sqlite3_busy_handler|busy-handler callback]) until there is no 7346** database writer and all readers are reading from the most recent database 7347** snapshot. ^It then checkpoints all frames in the log file and syncs the 7348** database file. ^This mode blocks new database writers while it is pending, 7349** but new database readers are allowed to continue unimpeded. 7350** 7351** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7352** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 7353** that after checkpointing the log file it blocks (calls the 7354** [busy-handler callback]) 7355** until all readers are reading from the database file only. ^This ensures 7356** that the next writer will restart the log file from the beginning. 7357** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 7358** database writer attempts while it is pending, but does not impede readers. 7359** 7360** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 7361** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 7362** addition that it also truncates the log file to zero bytes just prior 7363** to a successful return. 7364** </dl> 7365** 7366** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 7367** the log file or to -1 if the checkpoint could not run because 7368** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 7369** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 7370** log file (including any that were already checkpointed before the function 7371** was called) or to -1 if the checkpoint could not run due to an error or 7372** because the database is not in WAL mode. ^Note that upon successful 7373** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 7374** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 7375** 7376** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 7377** any other process is running a checkpoint operation at the same time, the 7378** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 7379** busy-handler configured, it will not be invoked in this case. 7380** 7381** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 7382** exclusive "writer" lock on the database file. ^If the writer lock cannot be 7383** obtained immediately, and a busy-handler is configured, it is invoked and 7384** the writer lock retried until either the busy-handler returns 0 or the lock 7385** is successfully obtained. ^The busy-handler is also invoked while waiting for 7386** database readers as described above. ^If the busy-handler returns 0 before 7387** the writer lock is obtained or while waiting for database readers, the 7388** checkpoint operation proceeds from that point in the same way as 7389** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7390** without blocking any further. ^SQLITE_BUSY is returned in this case. 7391** 7392** ^If parameter zDb is NULL or points to a zero length string, then the 7393** specified operation is attempted on all WAL databases [attached] to 7394** [database connection] db. In this case the 7395** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 7396** an SQLITE_BUSY error is encountered when processing one or more of the 7397** attached WAL databases, the operation is still attempted on any remaining 7398** attached databases and SQLITE_BUSY is returned at the end. ^If any other 7399** error occurs while processing an attached database, processing is abandoned 7400** and the error code is returned to the caller immediately. ^If no error 7401** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7402** databases, SQLITE_OK is returned. 7403** 7404** ^If database zDb is the name of an attached database that is not in WAL 7405** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 7406** zDb is not NULL (or a zero length string) and is not the name of any 7407** attached database, SQLITE_ERROR is returned to the caller. 7408** 7409** ^Unless it returns SQLITE_MISUSE, 7410** the sqlite3_wal_checkpoint_v2() interface 7411** sets the error information that is queried by 7412** [sqlite3_errcode()] and [sqlite3_errmsg()]. 7413** 7414** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 7415** from SQL. 7416*/ 7417SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint_v2( 7418 sqlite3 *db, /* Database handle */ 7419 const char *zDb, /* Name of attached database (or NULL) */ 7420 int eMode, /* SQLITE_CHECKPOINT_* value */ 7421 int *pnLog, /* OUT: Size of WAL log in frames */ 7422 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7423); 7424 7425/* 7426** CAPI3REF: Checkpoint Mode Values 7427** KEYWORDS: {checkpoint mode} 7428** 7429** These constants define all valid values for the "checkpoint mode" passed 7430** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 7431** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 7432** meaning of each of these checkpoint modes. 7433*/ 7434#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 7435#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 7436#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 7437#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 7438 7439/* 7440** CAPI3REF: Virtual Table Interface Configuration 7441** 7442** This function may be called by either the [xConnect] or [xCreate] method 7443** of a [virtual table] implementation to configure 7444** various facets of the virtual table interface. 7445** 7446** If this interface is invoked outside the context of an xConnect or 7447** xCreate virtual table method then the behavior is undefined. 7448** 7449** At present, there is only one option that may be configured using 7450** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7451** may be added in the future. 7452*/ 7453SQLITE_API int SQLITE_CDECL sqlite3_vtab_config(sqlite3*, int op, ...); 7454 7455/* 7456** CAPI3REF: Virtual Table Configuration Options 7457** 7458** These macros define the various options to the 7459** [sqlite3_vtab_config()] interface that [virtual table] implementations 7460** can use to customize and optimize their behavior. 7461** 7462** <dl> 7463** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7464** <dd>Calls of the form 7465** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7466** where X is an integer. If X is zero, then the [virtual table] whose 7467** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7468** support constraints. In this configuration (which is the default) if 7469** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7470** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7471** specified as part of the users SQL statement, regardless of the actual 7472** ON CONFLICT mode specified. 7473** 7474** If X is non-zero, then the virtual table implementation guarantees 7475** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7476** any modifications to internal or persistent data structures have been made. 7477** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7478** is able to roll back a statement or database transaction, and abandon 7479** or continue processing the current SQL statement as appropriate. 7480** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7481** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7482** had been ABORT. 7483** 7484** Virtual table implementations that are required to handle OR REPLACE 7485** must do so within the [xUpdate] method. If a call to the 7486** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7487** CONFLICT policy is REPLACE, the virtual table implementation should 7488** silently replace the appropriate rows within the xUpdate callback and 7489** return SQLITE_OK. Or, if this is not possible, it may return 7490** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7491** constraint handling. 7492** </dl> 7493*/ 7494#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7495 7496/* 7497** CAPI3REF: Determine The Virtual Table Conflict Policy 7498** 7499** This function may only be called from within a call to the [xUpdate] method 7500** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7501** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7502** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7503** of the SQL statement that triggered the call to the [xUpdate] method of the 7504** [virtual table]. 7505*/ 7506SQLITE_API int SQLITE_STDCALL sqlite3_vtab_on_conflict(sqlite3 *); 7507 7508/* 7509** CAPI3REF: Conflict resolution modes 7510** KEYWORDS: {conflict resolution mode} 7511** 7512** These constants are returned by [sqlite3_vtab_on_conflict()] to 7513** inform a [virtual table] implementation what the [ON CONFLICT] mode 7514** is for the SQL statement being evaluated. 7515** 7516** Note that the [SQLITE_IGNORE] constant is also used as a potential 7517** return value from the [sqlite3_set_authorizer()] callback and that 7518** [SQLITE_ABORT] is also a [result code]. 7519*/ 7520#define SQLITE_ROLLBACK 1 7521/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7522#define SQLITE_FAIL 3 7523/* #define SQLITE_ABORT 4 // Also an error code */ 7524#define SQLITE_REPLACE 5 7525 7526/* 7527** CAPI3REF: Prepared Statement Scan Status Opcodes 7528** KEYWORDS: {scanstatus options} 7529** 7530** The following constants can be used for the T parameter to the 7531** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 7532** different metric for sqlite3_stmt_scanstatus() to return. 7533** 7534** When the value returned to V is a string, space to hold that string is 7535** managed by the prepared statement S and will be automatically freed when 7536** S is finalized. 7537** 7538** <dl> 7539** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 7540** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 7541** set to the total number of times that the X-th loop has run.</dd> 7542** 7543** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 7544** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 7545** to the total number of rows examined by all iterations of the X-th loop.</dd> 7546** 7547** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 7548** <dd>^The "double" variable pointed to by the T parameter will be set to the 7549** query planner's estimate for the average number of rows output from each 7550** iteration of the X-th loop. If the query planner's estimates was accurate, 7551** then this value will approximate the quotient NVISIT/NLOOP and the 7552** product of this value for all prior loops with the same SELECTID will 7553** be the NLOOP value for the current loop. 7554** 7555** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 7556** <dd>^The "const char *" variable pointed to by the T parameter will be set 7557** to a zero-terminated UTF-8 string containing the name of the index or table 7558** used for the X-th loop. 7559** 7560** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 7561** <dd>^The "const char *" variable pointed to by the T parameter will be set 7562** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 7563** description for the X-th loop. 7564** 7565** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 7566** <dd>^The "int" variable pointed to by the T parameter will be set to the 7567** "select-id" for the X-th loop. The select-id identifies which query or 7568** subquery the loop is part of. The main query has a select-id of zero. 7569** The select-id is the same value as is output in the first column 7570** of an [EXPLAIN QUERY PLAN] query. 7571** </dl> 7572*/ 7573#define SQLITE_SCANSTAT_NLOOP 0 7574#define SQLITE_SCANSTAT_NVISIT 1 7575#define SQLITE_SCANSTAT_EST 2 7576#define SQLITE_SCANSTAT_NAME 3 7577#define SQLITE_SCANSTAT_EXPLAIN 4 7578#define SQLITE_SCANSTAT_SELECTID 5 7579 7580/* 7581** CAPI3REF: Prepared Statement Scan Status 7582** 7583** This interface returns information about the predicted and measured 7584** performance for pStmt. Advanced applications can use this 7585** interface to compare the predicted and the measured performance and 7586** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 7587** 7588** Since this interface is expected to be rarely used, it is only 7589** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 7590** compile-time option. 7591** 7592** The "iScanStatusOp" parameter determines which status information to return. 7593** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 7594** of this interface is undefined. 7595** ^The requested measurement is written into a variable pointed to by 7596** the "pOut" parameter. 7597** Parameter "idx" identifies the specific loop to retrieve statistics for. 7598** Loops are numbered starting from zero. ^If idx is out of range - less than 7599** zero or greater than or equal to the total number of loops used to implement 7600** the statement - a non-zero value is returned and the variable that pOut 7601** points to is unchanged. 7602** 7603** ^Statistics might not be available for all loops in all statements. ^In cases 7604** where there exist loops with no available statistics, this function behaves 7605** as if the loop did not exist - it returns non-zero and leave the variable 7606** that pOut points to unchanged. 7607** 7608** See also: [sqlite3_stmt_scanstatus_reset()] 7609*/ 7610SQLITE_API SQLITE_EXPERIMENTAL int SQLITE_STDCALL sqlite3_stmt_scanstatus( 7611 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 7612 int idx, /* Index of loop to report on */ 7613 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 7614 void *pOut /* Result written here */ 7615); 7616 7617/* 7618** CAPI3REF: Zero Scan-Status Counters 7619** 7620** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 7621** 7622** This API is only available if the library is built with pre-processor 7623** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 7624*/ 7625SQLITE_API SQLITE_EXPERIMENTAL void SQLITE_STDCALL sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 7626 7627 7628/* 7629** Undo the hack that converts floating point types to integer for 7630** builds on processors without floating point support. 7631*/ 7632#ifdef SQLITE_OMIT_FLOATING_POINT 7633# undef double 7634#endif 7635 7636#ifdef __cplusplus 7637} /* End of the 'extern "C"' block */ 7638#endif 7639#endif /* _SQLITE3_H_ */ 7640 7641/* 7642** 2010 August 30 7643** 7644** The author disclaims copyright to this source code. In place of 7645** a legal notice, here is a blessing: 7646** 7647** May you do good and not evil. 7648** May you find forgiveness for yourself and forgive others. 7649** May you share freely, never taking more than you give. 7650** 7651************************************************************************* 7652*/ 7653 7654#ifndef _SQLITE3RTREE_H_ 7655#define _SQLITE3RTREE_H_ 7656 7657 7658#ifdef __cplusplus 7659extern "C" { 7660#endif 7661 7662typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry; 7663typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info; 7664 7665/* The double-precision datatype used by RTree depends on the 7666** SQLITE_RTREE_INT_ONLY compile-time option. 7667*/ 7668#ifdef SQLITE_RTREE_INT_ONLY 7669 typedef sqlite3_int64 sqlite3_rtree_dbl; 7670#else 7671 typedef double sqlite3_rtree_dbl; 7672#endif 7673 7674/* 7675** Register a geometry callback named zGeom that can be used as part of an 7676** R-Tree geometry query as follows: 7677** 7678** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...) 7679*/ 7680SQLITE_API int SQLITE_STDCALL sqlite3_rtree_geometry_callback( 7681 sqlite3 *db, 7682 const char *zGeom, 7683 int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*), 7684 void *pContext 7685); 7686 7687 7688/* 7689** A pointer to a structure of the following type is passed as the first 7690** argument to callbacks registered using rtree_geometry_callback(). 7691*/ 7692struct sqlite3_rtree_geometry { 7693 void *pContext; /* Copy of pContext passed to s_r_g_c() */ 7694 int nParam; /* Size of array aParam[] */ 7695 sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */ 7696 void *pUser; /* Callback implementation user data */ 7697 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */ 7698}; 7699 7700/* 7701** Register a 2nd-generation geometry callback named zScore that can be 7702** used as part of an R-Tree geometry query as follows: 7703** 7704** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...) 7705*/ 7706SQLITE_API int SQLITE_STDCALL sqlite3_rtree_query_callback( 7707 sqlite3 *db, 7708 const char *zQueryFunc, 7709 int (*xQueryFunc)(sqlite3_rtree_query_info*), 7710 void *pContext, 7711 void (*xDestructor)(void*) 7712); 7713 7714 7715/* 7716** A pointer to a structure of the following type is passed as the 7717** argument to scored geometry callback registered using 7718** sqlite3_rtree_query_callback(). 7719** 7720** Note that the first 5 fields of this structure are identical to 7721** sqlite3_rtree_geometry. This structure is a subclass of 7722** sqlite3_rtree_geometry. 7723*/ 7724struct sqlite3_rtree_query_info { 7725 void *pContext; /* pContext from when function registered */ 7726 int nParam; /* Number of function parameters */ 7727 sqlite3_rtree_dbl *aParam; /* value of function parameters */ 7728 void *pUser; /* callback can use this, if desired */ 7729 void (*xDelUser)(void*); /* function to free pUser */ 7730 sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */ 7731 unsigned int *anQueue; /* Number of pending entries in the queue */ 7732 int nCoord; /* Number of coordinates */ 7733 int iLevel; /* Level of current node or entry */ 7734 int mxLevel; /* The largest iLevel value in the tree */ 7735 sqlite3_int64 iRowid; /* Rowid for current entry */ 7736 sqlite3_rtree_dbl rParentScore; /* Score of parent node */ 7737 int eParentWithin; /* Visibility of parent node */ 7738 int eWithin; /* OUT: Visiblity */ 7739 sqlite3_rtree_dbl rScore; /* OUT: Write the score here */ 7740}; 7741 7742/* 7743** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin. 7744*/ 7745#define NOT_WITHIN 0 /* Object completely outside of query region */ 7746#define PARTLY_WITHIN 1 /* Object partially overlaps query region */ 7747#define FULLY_WITHIN 2 /* Object fully contained within query region */ 7748 7749 7750#ifdef __cplusplus 7751} /* end of the 'extern "C"' block */ 7752#endif 7753 7754#endif /* ifndef _SQLITE3RTREE_H_ */ 7755 7756