1/* 2** 2001-09-15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are supposed to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef SQLITE3_H 34#define SQLITE3_H 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_APICALL 58# define SQLITE_APICALL 59#endif 60#ifndef SQLITE_STDCALL 61# define SQLITE_STDCALL SQLITE_APICALL 62#endif 63#ifndef SQLITE_CALLBACK 64# define SQLITE_CALLBACK 65#endif 66#ifndef SQLITE_SYSAPI 67# define SQLITE_SYSAPI 68#endif 69 70/* 71** These no-op macros are used in front of interfaces to mark those 72** interfaces as either deprecated or experimental. New applications 73** should not use deprecated interfaces - they are supported for backwards 74** compatibility only. Application writers should be aware that 75** experimental interfaces are subject to change in point releases. 76** 77** These macros used to resolve to various kinds of compiler magic that 78** would generate warning messages when they were used. But that 79** compiler magic ended up generating such a flurry of bug reports 80** that we have taken it all out and gone back to using simple 81** noop macros. 82*/ 83#define SQLITE_DEPRECATED 84#define SQLITE_EXPERIMENTAL 85 86/* 87** Ensure these symbols were not defined by some previous header file. 88*/ 89#ifdef SQLITE_VERSION 90# undef SQLITE_VERSION 91#endif 92#ifdef SQLITE_VERSION_NUMBER 93# undef SQLITE_VERSION_NUMBER 94#endif 95 96/* 97** CAPI3REF: Compile-Time Library Version Numbers 98** 99** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 100** evaluates to a string literal that is the SQLite version in the 101** format "X.Y.Z" where X is the major version number (always 3 for 102** SQLite3) and Y is the minor version number and Z is the release number.)^ 103** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 104** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 105** numbers used in [SQLITE_VERSION].)^ 106** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 107** be larger than the release from which it is derived. Either Y will 108** be held constant and Z will be incremented or else Y will be incremented 109** and Z will be reset to zero. 110** 111** Since [version 3.6.18] ([dateof:3.6.18]), 112** SQLite source code has been stored in the 113** <a href="http://www.fossil-scm.org/">Fossil configuration management 114** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 115** a string which identifies a particular check-in of SQLite 116** within its configuration management system. ^The SQLITE_SOURCE_ID 117** string contains the date and time of the check-in (UTC) and a SHA1 118** or SHA3-256 hash of the entire source tree. If the source code has 119** been edited in any way since it was last checked in, then the last 120** four hexadecimal digits of the hash may be modified. 121** 122** See also: [sqlite3_libversion()], 123** [sqlite3_libversion_number()], [sqlite3_sourceid()], 124** [sqlite_version()] and [sqlite_source_id()]. 125*/ 126#define SQLITE_VERSION "--VERS--" 127#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 128#define SQLITE_SOURCE_ID "--SOURCE-ID--" 129 130/* 131** CAPI3REF: Run-Time Library Version Numbers 132** KEYWORDS: sqlite3_version sqlite3_sourceid 133** 134** These interfaces provide the same information as the [SQLITE_VERSION], 135** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 136** but are associated with the library instead of the header file. ^(Cautious 137** programmers might include assert() statements in their application to 138** verify that values returned by these interfaces match the macros in 139** the header, and thus ensure that the application is 140** compiled with matching library and header files. 141** 142** <blockquote><pre> 143** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 144** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 ); 145** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 146** </pre></blockquote>)^ 147** 148** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 149** macro. ^The sqlite3_libversion() function returns a pointer to the 150** to the sqlite3_version[] string constant. The sqlite3_libversion() 151** function is provided for use in DLLs since DLL users usually do not have 152** direct access to string constants within the DLL. ^The 153** sqlite3_libversion_number() function returns an integer equal to 154** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns 155** a pointer to a string constant whose value is the same as the 156** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built 157** using an edited copy of [the amalgamation], then the last four characters 158** of the hash might be different from [SQLITE_SOURCE_ID].)^ 159** 160** See also: [sqlite_version()] and [sqlite_source_id()]. 161*/ 162SQLITE_EXTERN const char sqlite3_version[]; 163const char *sqlite3_libversion(void); 164const char *sqlite3_sourceid(void); 165int sqlite3_libversion_number(void); 166 167/* 168** CAPI3REF: Run-Time Library Compilation Options Diagnostics 169** 170** ^The sqlite3_compileoption_used() function returns 0 or 1 171** indicating whether the specified option was defined at 172** compile time. ^The SQLITE_ prefix may be omitted from the 173** option name passed to sqlite3_compileoption_used(). 174** 175** ^The sqlite3_compileoption_get() function allows iterating 176** over the list of options that were defined at compile time by 177** returning the N-th compile time option string. ^If N is out of range, 178** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 179** prefix is omitted from any strings returned by 180** sqlite3_compileoption_get(). 181** 182** ^Support for the diagnostic functions sqlite3_compileoption_used() 183** and sqlite3_compileoption_get() may be omitted by specifying the 184** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 185** 186** See also: SQL functions [sqlite_compileoption_used()] and 187** [sqlite_compileoption_get()] and the [compile_options pragma]. 188*/ 189#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 190int sqlite3_compileoption_used(const char *zOptName); 191const char *sqlite3_compileoption_get(int N); 192#else 193# define sqlite3_compileoption_used(X) 0 194# define sqlite3_compileoption_get(X) ((void*)0) 195#endif 196 197/* 198** CAPI3REF: Test To See If The Library Is Threadsafe 199** 200** ^The sqlite3_threadsafe() function returns zero if and only if 201** SQLite was compiled with mutexing code omitted due to the 202** [SQLITE_THREADSAFE] compile-time option being set to 0. 203** 204** SQLite can be compiled with or without mutexes. When 205** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 206** are enabled and SQLite is threadsafe. When the 207** [SQLITE_THREADSAFE] macro is 0, 208** the mutexes are omitted. Without the mutexes, it is not safe 209** to use SQLite concurrently from more than one thread. 210** 211** Enabling mutexes incurs a measurable performance penalty. 212** So if speed is of utmost importance, it makes sense to disable 213** the mutexes. But for maximum safety, mutexes should be enabled. 214** ^The default behavior is for mutexes to be enabled. 215** 216** This interface can be used by an application to make sure that the 217** version of SQLite that it is linking against was compiled with 218** the desired setting of the [SQLITE_THREADSAFE] macro. 219** 220** This interface only reports on the compile-time mutex setting 221** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 222** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 223** can be fully or partially disabled using a call to [sqlite3_config()] 224** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 225** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 226** sqlite3_threadsafe() function shows only the compile-time setting of 227** thread safety, not any run-time changes to that setting made by 228** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 229** is unchanged by calls to sqlite3_config().)^ 230** 231** See the [threading mode] documentation for additional information. 232*/ 233int sqlite3_threadsafe(void); 234 235/* 236** CAPI3REF: Database Connection Handle 237** KEYWORDS: {database connection} {database connections} 238** 239** Each open SQLite database is represented by a pointer to an instance of 240** the opaque structure named "sqlite3". It is useful to think of an sqlite3 241** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 242** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 243** and [sqlite3_close_v2()] are its destructors. There are many other 244** interfaces (such as 245** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 246** [sqlite3_busy_timeout()] to name but three) that are methods on an 247** sqlite3 object. 248*/ 249typedef struct sqlite3 sqlite3; 250 251/* 252** CAPI3REF: 64-Bit Integer Types 253** KEYWORDS: sqlite_int64 sqlite_uint64 254** 255** Because there is no cross-platform way to specify 64-bit integer types 256** SQLite includes typedefs for 64-bit signed and unsigned integers. 257** 258** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 259** The sqlite_int64 and sqlite_uint64 types are supported for backwards 260** compatibility only. 261** 262** ^The sqlite3_int64 and sqlite_int64 types can store integer values 263** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 264** sqlite3_uint64 and sqlite_uint64 types can store integer values 265** between 0 and +18446744073709551615 inclusive. 266*/ 267#ifdef SQLITE_INT64_TYPE 268 typedef SQLITE_INT64_TYPE sqlite_int64; 269# ifdef SQLITE_UINT64_TYPE 270 typedef SQLITE_UINT64_TYPE sqlite_uint64; 271# else 272 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 273# endif 274#elif defined(_MSC_VER) || defined(__BORLANDC__) 275 typedef __int64 sqlite_int64; 276 typedef unsigned __int64 sqlite_uint64; 277#else 278 typedef long long int sqlite_int64; 279 typedef unsigned long long int sqlite_uint64; 280#endif 281typedef sqlite_int64 sqlite3_int64; 282typedef sqlite_uint64 sqlite3_uint64; 283 284/* 285** If compiling for a processor that lacks floating point support, 286** substitute integer for floating-point. 287*/ 288#ifdef SQLITE_OMIT_FLOATING_POINT 289# define double sqlite3_int64 290#endif 291 292/* 293** CAPI3REF: Closing A Database Connection 294** DESTRUCTOR: sqlite3 295** 296** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 297** for the [sqlite3] object. 298** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 299** the [sqlite3] object is successfully destroyed and all associated 300** resources are deallocated. 301** 302** Ideally, applications should [sqlite3_finalize | finalize] all 303** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and 304** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 305** with the [sqlite3] object prior to attempting to close the object. 306** ^If the database connection is associated with unfinalized prepared 307** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then 308** sqlite3_close() will leave the database connection open and return 309** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared 310** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups, 311** it returns [SQLITE_OK] regardless, but instead of deallocating the database 312** connection immediately, it marks the database connection as an unusable 313** "zombie" and makes arrangements to automatically deallocate the database 314** connection after all prepared statements are finalized, all BLOB handles 315** are closed, and all backups have finished. The sqlite3_close_v2() interface 316** is intended for use with host languages that are garbage collected, and 317** where the order in which destructors are called is arbitrary. 318** 319** ^If an [sqlite3] object is destroyed while a transaction is open, 320** the transaction is automatically rolled back. 321** 322** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 323** must be either a NULL 324** pointer or an [sqlite3] object pointer obtained 325** from [sqlite3_open()], [sqlite3_open16()], or 326** [sqlite3_open_v2()], and not previously closed. 327** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 328** argument is a harmless no-op. 329*/ 330int sqlite3_close(sqlite3*); 331int sqlite3_close_v2(sqlite3*); 332 333/* 334** The type for a callback function. 335** This is legacy and deprecated. It is included for historical 336** compatibility and is not documented. 337*/ 338typedef int (*sqlite3_callback)(void*,int,char**, char**); 339 340/* 341** CAPI3REF: One-Step Query Execution Interface 342** METHOD: sqlite3 343** 344** The sqlite3_exec() interface is a convenience wrapper around 345** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 346** that allows an application to run multiple statements of SQL 347** without having to use a lot of C code. 348** 349** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 350** semicolon-separate SQL statements passed into its 2nd argument, 351** in the context of the [database connection] passed in as its 1st 352** argument. ^If the callback function of the 3rd argument to 353** sqlite3_exec() is not NULL, then it is invoked for each result row 354** coming out of the evaluated SQL statements. ^The 4th argument to 355** sqlite3_exec() is relayed through to the 1st argument of each 356** callback invocation. ^If the callback pointer to sqlite3_exec() 357** is NULL, then no callback is ever invoked and result rows are 358** ignored. 359** 360** ^If an error occurs while evaluating the SQL statements passed into 361** sqlite3_exec(), then execution of the current statement stops and 362** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 363** is not NULL then any error message is written into memory obtained 364** from [sqlite3_malloc()] and passed back through the 5th parameter. 365** To avoid memory leaks, the application should invoke [sqlite3_free()] 366** on error message strings returned through the 5th parameter of 367** sqlite3_exec() after the error message string is no longer needed. 368** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 369** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 370** NULL before returning. 371** 372** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 373** routine returns SQLITE_ABORT without invoking the callback again and 374** without running any subsequent SQL statements. 375** 376** ^The 2nd argument to the sqlite3_exec() callback function is the 377** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 378** callback is an array of pointers to strings obtained as if from 379** [sqlite3_column_text()], one for each column. ^If an element of a 380** result row is NULL then the corresponding string pointer for the 381** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 382** sqlite3_exec() callback is an array of pointers to strings where each 383** entry represents the name of corresponding result column as obtained 384** from [sqlite3_column_name()]. 385** 386** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 387** to an empty string, or a pointer that contains only whitespace and/or 388** SQL comments, then no SQL statements are evaluated and the database 389** is not changed. 390** 391** Restrictions: 392** 393** <ul> 394** <li> The application must ensure that the 1st parameter to sqlite3_exec() 395** is a valid and open [database connection]. 396** <li> The application must not close the [database connection] specified by 397** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 398** <li> The application must not modify the SQL statement text passed into 399** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 400** </ul> 401*/ 402int sqlite3_exec( 403 sqlite3*, /* An open database */ 404 const char *sql, /* SQL to be evaluated */ 405 int (*callback)(void*,int,char**,char**), /* Callback function */ 406 void *, /* 1st argument to callback */ 407 char **errmsg /* Error msg written here */ 408); 409 410/* 411** CAPI3REF: Result Codes 412** KEYWORDS: {result code definitions} 413** 414** Many SQLite functions return an integer result code from the set shown 415** here in order to indicate success or failure. 416** 417** New error codes may be added in future versions of SQLite. 418** 419** See also: [extended result code definitions] 420*/ 421#define SQLITE_OK 0 /* Successful result */ 422/* beginning-of-error-codes */ 423#define SQLITE_ERROR 1 /* Generic error */ 424#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 425#define SQLITE_PERM 3 /* Access permission denied */ 426#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 427#define SQLITE_BUSY 5 /* The database file is locked */ 428#define SQLITE_LOCKED 6 /* A table in the database is locked */ 429#define SQLITE_NOMEM 7 /* A malloc() failed */ 430#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 431#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 432#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 433#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 434#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 435#define SQLITE_FULL 13 /* Insertion failed because database is full */ 436#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 437#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 438#define SQLITE_EMPTY 16 /* Internal use only */ 439#define SQLITE_SCHEMA 17 /* The database schema changed */ 440#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 441#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 442#define SQLITE_MISMATCH 20 /* Data type mismatch */ 443#define SQLITE_MISUSE 21 /* Library used incorrectly */ 444#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 445#define SQLITE_AUTH 23 /* Authorization denied */ 446#define SQLITE_FORMAT 24 /* Not used */ 447#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 448#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 449#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 450#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 451#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 452#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 453/* end-of-error-codes */ 454 455/* 456** CAPI3REF: Extended Result Codes 457** KEYWORDS: {extended result code definitions} 458** 459** In its default configuration, SQLite API routines return one of 30 integer 460** [result codes]. However, experience has shown that many of 461** these result codes are too coarse-grained. They do not provide as 462** much information about problems as programmers might like. In an effort to 463** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 464** and later) include 465** support for additional result codes that provide more detailed information 466** about errors. These [extended result codes] are enabled or disabled 467** on a per database connection basis using the 468** [sqlite3_extended_result_codes()] API. Or, the extended code for 469** the most recent error can be obtained using 470** [sqlite3_extended_errcode()]. 471*/ 472#define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8)) 473#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8)) 474#define SQLITE_ERROR_SNAPSHOT (SQLITE_ERROR | (3<<8)) 475#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 476#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 477#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 478#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 479#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 480#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 481#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 482#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 483#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 484#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 485#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 486#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 487#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 488#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 489#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 490#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 491#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 492#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 493#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 494#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 495#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 496#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 497#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 498#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 499#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 500#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 501#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 502#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 503#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 504#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 505#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 506#define SQLITE_IOERR_DATA (SQLITE_IOERR | (32<<8)) 507#define SQLITE_IOERR_CORRUPTFS (SQLITE_IOERR | (33<<8)) 508#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 509#define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8)) 510#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 511#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 512#define SQLITE_BUSY_TIMEOUT (SQLITE_BUSY | (3<<8)) 513#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 514#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 515#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 516#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 517#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */ 518#define SQLITE_CANTOPEN_SYMLINK (SQLITE_CANTOPEN | (6<<8)) 519#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 520#define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8)) 521#define SQLITE_CORRUPT_INDEX (SQLITE_CORRUPT | (3<<8)) 522#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 523#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 524#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 525#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 526#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8)) 527#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8)) 528#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 529#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 530#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 531#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 532#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 533#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 534#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 535#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 536#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 537#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 538#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 539#define SQLITE_CONSTRAINT_PINNED (SQLITE_CONSTRAINT |(11<<8)) 540#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 541#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 542#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 543#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 544#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 545#define SQLITE_OK_SYMLINK (SQLITE_OK | (2<<8)) 546 547/* 548** CAPI3REF: Flags For File Open Operations 549** 550** These bit values are intended for use in the 551** 3rd parameter to the [sqlite3_open_v2()] interface and 552** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 553*/ 554#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 555#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 556#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 557#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 558#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 559#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 560#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 561#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 562#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 563#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 564#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 565#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 566#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 567#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 568#define SQLITE_OPEN_SUPER_JOURNAL 0x00004000 /* VFS only */ 569#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 570#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 571#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 572#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 573#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 574#define SQLITE_OPEN_NOFOLLOW 0x01000000 /* Ok for sqlite3_open_v2() */ 575 576/* Reserved: 0x00F00000 */ 577/* Legacy compatibility: */ 578#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 579 580 581/* 582** CAPI3REF: Device Characteristics 583** 584** The xDeviceCharacteristics method of the [sqlite3_io_methods] 585** object returns an integer which is a vector of these 586** bit values expressing I/O characteristics of the mass storage 587** device that holds the file that the [sqlite3_io_methods] 588** refers to. 589** 590** The SQLITE_IOCAP_ATOMIC property means that all writes of 591** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 592** mean that writes of blocks that are nnn bytes in size and 593** are aligned to an address which is an integer multiple of 594** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 595** that when data is appended to a file, the data is appended 596** first then the size of the file is extended, never the other 597** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 598** information is written to disk in the same order as calls 599** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 600** after reboot following a crash or power loss, the only bytes in a 601** file that were written at the application level might have changed 602** and that adjacent bytes, even bytes within the same sector are 603** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 604** flag indicates that a file cannot be deleted when open. The 605** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 606** read-only media and cannot be changed even by processes with 607** elevated privileges. 608** 609** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 610** filesystem supports doing multiple write operations atomically when those 611** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 612** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 613*/ 614#define SQLITE_IOCAP_ATOMIC 0x00000001 615#define SQLITE_IOCAP_ATOMIC512 0x00000002 616#define SQLITE_IOCAP_ATOMIC1K 0x00000004 617#define SQLITE_IOCAP_ATOMIC2K 0x00000008 618#define SQLITE_IOCAP_ATOMIC4K 0x00000010 619#define SQLITE_IOCAP_ATOMIC8K 0x00000020 620#define SQLITE_IOCAP_ATOMIC16K 0x00000040 621#define SQLITE_IOCAP_ATOMIC32K 0x00000080 622#define SQLITE_IOCAP_ATOMIC64K 0x00000100 623#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 624#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 625#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 626#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 627#define SQLITE_IOCAP_IMMUTABLE 0x00002000 628#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 629 630/* 631** CAPI3REF: File Locking Levels 632** 633** SQLite uses one of these integer values as the second 634** argument to calls it makes to the xLock() and xUnlock() methods 635** of an [sqlite3_io_methods] object. 636*/ 637#define SQLITE_LOCK_NONE 0 638#define SQLITE_LOCK_SHARED 1 639#define SQLITE_LOCK_RESERVED 2 640#define SQLITE_LOCK_PENDING 3 641#define SQLITE_LOCK_EXCLUSIVE 4 642 643/* 644** CAPI3REF: Synchronization Type Flags 645** 646** When SQLite invokes the xSync() method of an 647** [sqlite3_io_methods] object it uses a combination of 648** these integer values as the second argument. 649** 650** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 651** sync operation only needs to flush data to mass storage. Inode 652** information need not be flushed. If the lower four bits of the flag 653** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 654** If the lower four bits equal SQLITE_SYNC_FULL, that means 655** to use Mac OS X style fullsync instead of fsync(). 656** 657** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 658** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 659** settings. The [synchronous pragma] determines when calls to the 660** xSync VFS method occur and applies uniformly across all platforms. 661** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 662** energetic or rigorous or forceful the sync operations are and 663** only make a difference on Mac OSX for the default SQLite code. 664** (Third-party VFS implementations might also make the distinction 665** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 666** operating systems natively supported by SQLite, only Mac OSX 667** cares about the difference.) 668*/ 669#define SQLITE_SYNC_NORMAL 0x00002 670#define SQLITE_SYNC_FULL 0x00003 671#define SQLITE_SYNC_DATAONLY 0x00010 672 673/* 674** CAPI3REF: OS Interface Open File Handle 675** 676** An [sqlite3_file] object represents an open file in the 677** [sqlite3_vfs | OS interface layer]. Individual OS interface 678** implementations will 679** want to subclass this object by appending additional fields 680** for their own use. The pMethods entry is a pointer to an 681** [sqlite3_io_methods] object that defines methods for performing 682** I/O operations on the open file. 683*/ 684typedef struct sqlite3_file sqlite3_file; 685struct sqlite3_file { 686 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 687}; 688 689/* 690** CAPI3REF: OS Interface File Virtual Methods Object 691** 692** Every file opened by the [sqlite3_vfs.xOpen] method populates an 693** [sqlite3_file] object (or, more commonly, a subclass of the 694** [sqlite3_file] object) with a pointer to an instance of this object. 695** This object defines the methods used to perform various operations 696** against the open file represented by the [sqlite3_file] object. 697** 698** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 699** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 700** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 701** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 702** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 703** to NULL. 704** 705** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 706** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 707** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 708** flag may be ORed in to indicate that only the data of the file 709** and not its inode needs to be synced. 710** 711** The integer values to xLock() and xUnlock() are one of 712** <ul> 713** <li> [SQLITE_LOCK_NONE], 714** <li> [SQLITE_LOCK_SHARED], 715** <li> [SQLITE_LOCK_RESERVED], 716** <li> [SQLITE_LOCK_PENDING], or 717** <li> [SQLITE_LOCK_EXCLUSIVE]. 718** </ul> 719** xLock() increases the lock. xUnlock() decreases the lock. 720** The xCheckReservedLock() method checks whether any database connection, 721** either in this process or in some other process, is holding a RESERVED, 722** PENDING, or EXCLUSIVE lock on the file. It returns true 723** if such a lock exists and false otherwise. 724** 725** The xFileControl() method is a generic interface that allows custom 726** VFS implementations to directly control an open file using the 727** [sqlite3_file_control()] interface. The second "op" argument is an 728** integer opcode. The third argument is a generic pointer intended to 729** point to a structure that may contain arguments or space in which to 730** write return values. Potential uses for xFileControl() might be 731** functions to enable blocking locks with timeouts, to change the 732** locking strategy (for example to use dot-file locks), to inquire 733** about the status of a lock, or to break stale locks. The SQLite 734** core reserves all opcodes less than 100 for its own use. 735** A [file control opcodes | list of opcodes] less than 100 is available. 736** Applications that define a custom xFileControl method should use opcodes 737** greater than 100 to avoid conflicts. VFS implementations should 738** return [SQLITE_NOTFOUND] for file control opcodes that they do not 739** recognize. 740** 741** The xSectorSize() method returns the sector size of the 742** device that underlies the file. The sector size is the 743** minimum write that can be performed without disturbing 744** other bytes in the file. The xDeviceCharacteristics() 745** method returns a bit vector describing behaviors of the 746** underlying device: 747** 748** <ul> 749** <li> [SQLITE_IOCAP_ATOMIC] 750** <li> [SQLITE_IOCAP_ATOMIC512] 751** <li> [SQLITE_IOCAP_ATOMIC1K] 752** <li> [SQLITE_IOCAP_ATOMIC2K] 753** <li> [SQLITE_IOCAP_ATOMIC4K] 754** <li> [SQLITE_IOCAP_ATOMIC8K] 755** <li> [SQLITE_IOCAP_ATOMIC16K] 756** <li> [SQLITE_IOCAP_ATOMIC32K] 757** <li> [SQLITE_IOCAP_ATOMIC64K] 758** <li> [SQLITE_IOCAP_SAFE_APPEND] 759** <li> [SQLITE_IOCAP_SEQUENTIAL] 760** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 761** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 762** <li> [SQLITE_IOCAP_IMMUTABLE] 763** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 764** </ul> 765** 766** The SQLITE_IOCAP_ATOMIC property means that all writes of 767** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 768** mean that writes of blocks that are nnn bytes in size and 769** are aligned to an address which is an integer multiple of 770** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 771** that when data is appended to a file, the data is appended 772** first then the size of the file is extended, never the other 773** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 774** information is written to disk in the same order as calls 775** to xWrite(). 776** 777** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 778** in the unread portions of the buffer with zeros. A VFS that 779** fails to zero-fill short reads might seem to work. However, 780** failure to zero-fill short reads will eventually lead to 781** database corruption. 782*/ 783typedef struct sqlite3_io_methods sqlite3_io_methods; 784struct sqlite3_io_methods { 785 int iVersion; 786 int (*xClose)(sqlite3_file*); 787 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 788 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 789 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 790 int (*xSync)(sqlite3_file*, int flags); 791 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 792 int (*xLock)(sqlite3_file*, int); 793 int (*xUnlock)(sqlite3_file*, int); 794 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 795 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 796 int (*xSectorSize)(sqlite3_file*); 797 int (*xDeviceCharacteristics)(sqlite3_file*); 798 /* Methods above are valid for version 1 */ 799 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 800 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 801 void (*xShmBarrier)(sqlite3_file*); 802 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 803 /* Methods above are valid for version 2 */ 804 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 805 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 806 /* Methods above are valid for version 3 */ 807 /* Additional methods may be added in future releases */ 808}; 809 810/* 811** CAPI3REF: Standard File Control Opcodes 812** KEYWORDS: {file control opcodes} {file control opcode} 813** 814** These integer constants are opcodes for the xFileControl method 815** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 816** interface. 817** 818** <ul> 819** <li>[[SQLITE_FCNTL_LOCKSTATE]] 820** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 821** opcode causes the xFileControl method to write the current state of 822** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 823** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 824** into an integer that the pArg argument points to. This capability 825** is used during testing and is only available when the SQLITE_TEST 826** compile-time option is used. 827** 828** <li>[[SQLITE_FCNTL_SIZE_HINT]] 829** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 830** layer a hint of how large the database file will grow to be during the 831** current transaction. This hint is not guaranteed to be accurate but it 832** is often close. The underlying VFS might choose to preallocate database 833** file space based on this hint in order to help writes to the database 834** file run faster. 835** 836** <li>[[SQLITE_FCNTL_SIZE_LIMIT]] 837** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that 838** implements [sqlite3_deserialize()] to set an upper bound on the size 839** of the in-memory database. The argument is a pointer to a [sqlite3_int64]. 840** If the integer pointed to is negative, then it is filled in with the 841** current limit. Otherwise the limit is set to the larger of the value 842** of the integer pointed to and the current database size. The integer 843** pointed to is set to the new limit. 844** 845** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 846** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 847** extends and truncates the database file in chunks of a size specified 848** by the user. The fourth argument to [sqlite3_file_control()] should 849** point to an integer (type int) containing the new chunk-size to use 850** for the nominated database. Allocating database file space in large 851** chunks (say 1MB at a time), may reduce file-system fragmentation and 852** improve performance on some systems. 853** 854** <li>[[SQLITE_FCNTL_FILE_POINTER]] 855** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 856** to the [sqlite3_file] object associated with a particular database 857** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 858** 859** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 860** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 861** to the [sqlite3_file] object associated with the journal file (either 862** the [rollback journal] or the [write-ahead log]) for a particular database 863** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 864** 865** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 866** No longer in use. 867** 868** <li>[[SQLITE_FCNTL_SYNC]] 869** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 870** sent to the VFS immediately before the xSync method is invoked on a 871** database file descriptor. Or, if the xSync method is not invoked 872** because the user has configured SQLite with 873** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 874** of the xSync method. In most cases, the pointer argument passed with 875** this file-control is NULL. However, if the database file is being synced 876** as part of a multi-database commit, the argument points to a nul-terminated 877** string containing the transactions super-journal file name. VFSes that 878** do not need this signal should silently ignore this opcode. Applications 879** should not call [sqlite3_file_control()] with this opcode as doing so may 880** disrupt the operation of the specialized VFSes that do require it. 881** 882** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 883** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 884** and sent to the VFS after a transaction has been committed immediately 885** but before the database is unlocked. VFSes that do not need this signal 886** should silently ignore this opcode. Applications should not call 887** [sqlite3_file_control()] with this opcode as doing so may disrupt the 888** operation of the specialized VFSes that do require it. 889** 890** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 891** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 892** retry counts and intervals for certain disk I/O operations for the 893** windows [VFS] in order to provide robustness in the presence of 894** anti-virus programs. By default, the windows VFS will retry file read, 895** file write, and file delete operations up to 10 times, with a delay 896** of 25 milliseconds before the first retry and with the delay increasing 897** by an additional 25 milliseconds with each subsequent retry. This 898** opcode allows these two values (10 retries and 25 milliseconds of delay) 899** to be adjusted. The values are changed for all database connections 900** within the same process. The argument is a pointer to an array of two 901** integers where the first integer is the new retry count and the second 902** integer is the delay. If either integer is negative, then the setting 903** is not changed but instead the prior value of that setting is written 904** into the array entry, allowing the current retry settings to be 905** interrogated. The zDbName parameter is ignored. 906** 907** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 908** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 909** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 910** write ahead log ([WAL file]) and shared memory 911** files used for transaction control 912** are automatically deleted when the latest connection to the database 913** closes. Setting persistent WAL mode causes those files to persist after 914** close. Persisting the files is useful when other processes that do not 915** have write permission on the directory containing the database file want 916** to read the database file, as the WAL and shared memory files must exist 917** in order for the database to be readable. The fourth parameter to 918** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 919** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 920** WAL mode. If the integer is -1, then it is overwritten with the current 921** WAL persistence setting. 922** 923** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 924** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 925** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 926** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 927** xDeviceCharacteristics methods. The fourth parameter to 928** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 929** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 930** mode. If the integer is -1, then it is overwritten with the current 931** zero-damage mode setting. 932** 933** <li>[[SQLITE_FCNTL_OVERWRITE]] 934** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 935** a write transaction to indicate that, unless it is rolled back for some 936** reason, the entire database file will be overwritten by the current 937** transaction. This is used by VACUUM operations. 938** 939** <li>[[SQLITE_FCNTL_VFSNAME]] 940** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 941** all [VFSes] in the VFS stack. The names are of all VFS shims and the 942** final bottom-level VFS are written into memory obtained from 943** [sqlite3_malloc()] and the result is stored in the char* variable 944** that the fourth parameter of [sqlite3_file_control()] points to. 945** The caller is responsible for freeing the memory when done. As with 946** all file-control actions, there is no guarantee that this will actually 947** do anything. Callers should initialize the char* variable to a NULL 948** pointer in case this file-control is not implemented. This file-control 949** is intended for diagnostic use only. 950** 951** <li>[[SQLITE_FCNTL_VFS_POINTER]] 952** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 953** [VFSes] currently in use. ^(The argument X in 954** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 955** of type "[sqlite3_vfs] **". This opcodes will set *X 956** to a pointer to the top-level VFS.)^ 957** ^When there are multiple VFS shims in the stack, this opcode finds the 958** upper-most shim only. 959** 960** <li>[[SQLITE_FCNTL_PRAGMA]] 961** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 962** file control is sent to the open [sqlite3_file] object corresponding 963** to the database file to which the pragma statement refers. ^The argument 964** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 965** pointers to strings (char**) in which the second element of the array 966** is the name of the pragma and the third element is the argument to the 967** pragma or NULL if the pragma has no argument. ^The handler for an 968** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 969** of the char** argument point to a string obtained from [sqlite3_mprintf()] 970** or the equivalent and that string will become the result of the pragma or 971** the error message if the pragma fails. ^If the 972** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 973** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 974** file control returns [SQLITE_OK], then the parser assumes that the 975** VFS has handled the PRAGMA itself and the parser generates a no-op 976** prepared statement if result string is NULL, or that returns a copy 977** of the result string if the string is non-NULL. 978** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 979** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 980** that the VFS encountered an error while handling the [PRAGMA] and the 981** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 982** file control occurs at the beginning of pragma statement analysis and so 983** it is able to override built-in [PRAGMA] statements. 984** 985** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 986** ^The [SQLITE_FCNTL_BUSYHANDLER] 987** file-control may be invoked by SQLite on the database file handle 988** shortly after it is opened in order to provide a custom VFS with access 989** to the connection's busy-handler callback. The argument is of type (void**) 990** - an array of two (void *) values. The first (void *) actually points 991** to a function of type (int (*)(void *)). In order to invoke the connection's 992** busy-handler, this function should be invoked with the second (void *) in 993** the array as the only argument. If it returns non-zero, then the operation 994** should be retried. If it returns zero, the custom VFS should abandon the 995** current operation. 996** 997** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 998** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 999** to have SQLite generate a 1000** temporary filename using the same algorithm that is followed to generate 1001** temporary filenames for TEMP tables and other internal uses. The 1002** argument should be a char** which will be filled with the filename 1003** written into memory obtained from [sqlite3_malloc()]. The caller should 1004** invoke [sqlite3_free()] on the result to avoid a memory leak. 1005** 1006** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 1007** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 1008** maximum number of bytes that will be used for memory-mapped I/O. 1009** The argument is a pointer to a value of type sqlite3_int64 that 1010** is an advisory maximum number of bytes in the file to memory map. The 1011** pointer is overwritten with the old value. The limit is not changed if 1012** the value originally pointed to is negative, and so the current limit 1013** can be queried by passing in a pointer to a negative number. This 1014** file-control is used internally to implement [PRAGMA mmap_size]. 1015** 1016** <li>[[SQLITE_FCNTL_TRACE]] 1017** The [SQLITE_FCNTL_TRACE] file control provides advisory information 1018** to the VFS about what the higher layers of the SQLite stack are doing. 1019** This file control is used by some VFS activity tracing [shims]. 1020** The argument is a zero-terminated string. Higher layers in the 1021** SQLite stack may generate instances of this file control if 1022** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 1023** 1024** <li>[[SQLITE_FCNTL_HAS_MOVED]] 1025** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 1026** pointer to an integer and it writes a boolean into that integer depending 1027** on whether or not the file has been renamed, moved, or deleted since it 1028** was first opened. 1029** 1030** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1031** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1032** underlying native file handle associated with a file handle. This file 1033** control interprets its argument as a pointer to a native file handle and 1034** writes the resulting value there. 1035** 1036** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1037** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1038** opcode causes the xFileControl method to swap the file handle with the one 1039** pointed to by the pArg argument. This capability is used during testing 1040** and only needs to be supported when SQLITE_TEST is defined. 1041** 1042** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1043** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1044** be advantageous to block on the next WAL lock if the lock is not immediately 1045** available. The WAL subsystem issues this signal during rare 1046** circumstances in order to fix a problem with priority inversion. 1047** Applications should <em>not</em> use this file-control. 1048** 1049** <li>[[SQLITE_FCNTL_ZIPVFS]] 1050** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1051** VFS should return SQLITE_NOTFOUND for this opcode. 1052** 1053** <li>[[SQLITE_FCNTL_RBU]] 1054** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1055** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1056** this opcode. 1057** 1058** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1059** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1060** the file descriptor is placed in "batch write mode", which 1061** means all subsequent write operations will be deferred and done 1062** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1063** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1064** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1065** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1066** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1067** no VFS interface calls on the same [sqlite3_file] file descriptor 1068** except for calls to the xWrite method and the xFileControl method 1069** with [SQLITE_FCNTL_SIZE_HINT]. 1070** 1071** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1072** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1073** operations since the previous successful call to 1074** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1075** This file control returns [SQLITE_OK] if and only if the writes were 1076** all performed successfully and have been committed to persistent storage. 1077** ^Regardless of whether or not it is successful, this file control takes 1078** the file descriptor out of batch write mode so that all subsequent 1079** write operations are independent. 1080** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1081** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1082** 1083** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1084** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1085** operations since the previous successful call to 1086** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1087** ^This file control takes the file descriptor out of batch write mode 1088** so that all subsequent write operations are independent. 1089** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1090** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1091** 1092** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]] 1093** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS 1094** to block for up to M milliseconds before failing when attempting to 1095** obtain a file lock using the xLock or xShmLock methods of the VFS. 1096** The parameter is a pointer to a 32-bit signed integer that contains 1097** the value that M is to be set to. Before returning, the 32-bit signed 1098** integer is overwritten with the previous value of M. 1099** 1100** <li>[[SQLITE_FCNTL_DATA_VERSION]] 1101** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to 1102** a database file. The argument is a pointer to a 32-bit unsigned integer. 1103** The "data version" for the pager is written into the pointer. The 1104** "data version" changes whenever any change occurs to the corresponding 1105** database file, either through SQL statements on the same database 1106** connection or through transactions committed by separate database 1107** connections possibly in other processes. The [sqlite3_total_changes()] 1108** interface can be used to find if any database on the connection has changed, 1109** but that interface responds to changes on TEMP as well as MAIN and does 1110** not provide a mechanism to detect changes to MAIN only. Also, the 1111** [sqlite3_total_changes()] interface responds to internal changes only and 1112** omits changes made by other database connections. The 1113** [PRAGMA data_version] command provides a mechanism to detect changes to 1114** a single attached database that occur due to other database connections, 1115** but omits changes implemented by the database connection on which it is 1116** called. This file control is the only mechanism to detect changes that 1117** happen either internally or externally and that are associated with 1118** a particular attached database. 1119** 1120** <li>[[SQLITE_FCNTL_CKPT_START]] 1121** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint 1122** in wal mode before the client starts to copy pages from the wal 1123** file to the database file. 1124** 1125** <li>[[SQLITE_FCNTL_CKPT_DONE]] 1126** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint 1127** in wal mode after the client has finished copying pages from the wal 1128** file to the database file, but before the *-shm file is updated to 1129** record the fact that the pages have been checkpointed. 1130** </ul> 1131** 1132** <li>[[SQLITE_FCNTL_EXTERNAL_READER]] 1133** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect 1134** whether or not there is a database client in another process with a wal-mode 1135** transaction open on the database or not. It is only available on unix.The 1136** (void*) argument passed with this file-control should be a pointer to a 1137** value of type (int). The integer value is set to 1 if the database is a wal 1138** mode database and there exists at least one client in another process that 1139** currently has an SQL transaction open on the database. It is set to 0 if 1140** the database is not a wal-mode db, or if there is no such connection in any 1141** other process. This opcode cannot be used to detect transactions opened 1142** by clients within the current process, only within other processes. 1143** </ul> 1144** 1145** <li>[[SQLITE_FCNTL_CKSM_FILE]] 1146** Used by the cksmvfs VFS module only. 1147** </ul> 1148*/ 1149#define SQLITE_FCNTL_LOCKSTATE 1 1150#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1151#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1152#define SQLITE_FCNTL_LAST_ERRNO 4 1153#define SQLITE_FCNTL_SIZE_HINT 5 1154#define SQLITE_FCNTL_CHUNK_SIZE 6 1155#define SQLITE_FCNTL_FILE_POINTER 7 1156#define SQLITE_FCNTL_SYNC_OMITTED 8 1157#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1158#define SQLITE_FCNTL_PERSIST_WAL 10 1159#define SQLITE_FCNTL_OVERWRITE 11 1160#define SQLITE_FCNTL_VFSNAME 12 1161#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1162#define SQLITE_FCNTL_PRAGMA 14 1163#define SQLITE_FCNTL_BUSYHANDLER 15 1164#define SQLITE_FCNTL_TEMPFILENAME 16 1165#define SQLITE_FCNTL_MMAP_SIZE 18 1166#define SQLITE_FCNTL_TRACE 19 1167#define SQLITE_FCNTL_HAS_MOVED 20 1168#define SQLITE_FCNTL_SYNC 21 1169#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1170#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1171#define SQLITE_FCNTL_WAL_BLOCK 24 1172#define SQLITE_FCNTL_ZIPVFS 25 1173#define SQLITE_FCNTL_RBU 26 1174#define SQLITE_FCNTL_VFS_POINTER 27 1175#define SQLITE_FCNTL_JOURNAL_POINTER 28 1176#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1177#define SQLITE_FCNTL_PDB 30 1178#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1179#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1180#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1181#define SQLITE_FCNTL_LOCK_TIMEOUT 34 1182#define SQLITE_FCNTL_DATA_VERSION 35 1183#define SQLITE_FCNTL_SIZE_LIMIT 36 1184#define SQLITE_FCNTL_CKPT_DONE 37 1185#define SQLITE_FCNTL_RESERVE_BYTES 38 1186#define SQLITE_FCNTL_CKPT_START 39 1187#define SQLITE_FCNTL_EXTERNAL_READER 40 1188#define SQLITE_FCNTL_CKSM_FILE 41 1189 1190/* deprecated names */ 1191#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1192#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1193#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1194 1195 1196/* 1197** CAPI3REF: Mutex Handle 1198** 1199** The mutex module within SQLite defines [sqlite3_mutex] to be an 1200** abstract type for a mutex object. The SQLite core never looks 1201** at the internal representation of an [sqlite3_mutex]. It only 1202** deals with pointers to the [sqlite3_mutex] object. 1203** 1204** Mutexes are created using [sqlite3_mutex_alloc()]. 1205*/ 1206typedef struct sqlite3_mutex sqlite3_mutex; 1207 1208/* 1209** CAPI3REF: Loadable Extension Thunk 1210** 1211** A pointer to the opaque sqlite3_api_routines structure is passed as 1212** the third parameter to entry points of [loadable extensions]. This 1213** structure must be typedefed in order to work around compiler warnings 1214** on some platforms. 1215*/ 1216typedef struct sqlite3_api_routines sqlite3_api_routines; 1217 1218/* 1219** CAPI3REF: OS Interface Object 1220** 1221** An instance of the sqlite3_vfs object defines the interface between 1222** the SQLite core and the underlying operating system. The "vfs" 1223** in the name of the object stands for "virtual file system". See 1224** the [VFS | VFS documentation] for further information. 1225** 1226** The VFS interface is sometimes extended by adding new methods onto 1227** the end. Each time such an extension occurs, the iVersion field 1228** is incremented. The iVersion value started out as 1 in 1229** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1230** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1231** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1232** may be appended to the sqlite3_vfs object and the iVersion value 1233** may increase again in future versions of SQLite. 1234** Note that due to an oversight, the structure 1235** of the sqlite3_vfs object changed in the transition from 1236** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1237** and yet the iVersion field was not increased. 1238** 1239** The szOsFile field is the size of the subclassed [sqlite3_file] 1240** structure used by this VFS. mxPathname is the maximum length of 1241** a pathname in this VFS. 1242** 1243** Registered sqlite3_vfs objects are kept on a linked list formed by 1244** the pNext pointer. The [sqlite3_vfs_register()] 1245** and [sqlite3_vfs_unregister()] interfaces manage this list 1246** in a thread-safe way. The [sqlite3_vfs_find()] interface 1247** searches the list. Neither the application code nor the VFS 1248** implementation should use the pNext pointer. 1249** 1250** The pNext field is the only field in the sqlite3_vfs 1251** structure that SQLite will ever modify. SQLite will only access 1252** or modify this field while holding a particular static mutex. 1253** The application should never modify anything within the sqlite3_vfs 1254** object once the object has been registered. 1255** 1256** The zName field holds the name of the VFS module. The name must 1257** be unique across all VFS modules. 1258** 1259** [[sqlite3_vfs.xOpen]] 1260** ^SQLite guarantees that the zFilename parameter to xOpen 1261** is either a NULL pointer or string obtained 1262** from xFullPathname() with an optional suffix added. 1263** ^If a suffix is added to the zFilename parameter, it will 1264** consist of a single "-" character followed by no more than 1265** 11 alphanumeric and/or "-" characters. 1266** ^SQLite further guarantees that 1267** the string will be valid and unchanged until xClose() is 1268** called. Because of the previous sentence, 1269** the [sqlite3_file] can safely store a pointer to the 1270** filename if it needs to remember the filename for some reason. 1271** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1272** must invent its own temporary name for the file. ^Whenever the 1273** xFilename parameter is NULL it will also be the case that the 1274** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1275** 1276** The flags argument to xOpen() includes all bits set in 1277** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1278** or [sqlite3_open16()] is used, then flags includes at least 1279** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1280** If xOpen() opens a file read-only then it sets *pOutFlags to 1281** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1282** 1283** ^(SQLite will also add one of the following flags to the xOpen() 1284** call, depending on the object being opened: 1285** 1286** <ul> 1287** <li> [SQLITE_OPEN_MAIN_DB] 1288** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1289** <li> [SQLITE_OPEN_TEMP_DB] 1290** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1291** <li> [SQLITE_OPEN_TRANSIENT_DB] 1292** <li> [SQLITE_OPEN_SUBJOURNAL] 1293** <li> [SQLITE_OPEN_SUPER_JOURNAL] 1294** <li> [SQLITE_OPEN_WAL] 1295** </ul>)^ 1296** 1297** The file I/O implementation can use the object type flags to 1298** change the way it deals with files. For example, an application 1299** that does not care about crash recovery or rollback might make 1300** the open of a journal file a no-op. Writes to this journal would 1301** also be no-ops, and any attempt to read the journal would return 1302** SQLITE_IOERR. Or the implementation might recognize that a database 1303** file will be doing page-aligned sector reads and writes in a random 1304** order and set up its I/O subsystem accordingly. 1305** 1306** SQLite might also add one of the following flags to the xOpen method: 1307** 1308** <ul> 1309** <li> [SQLITE_OPEN_DELETEONCLOSE] 1310** <li> [SQLITE_OPEN_EXCLUSIVE] 1311** </ul> 1312** 1313** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1314** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1315** will be set for TEMP databases and their journals, transient 1316** databases, and subjournals. 1317** 1318** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1319** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1320** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1321** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1322** SQLITE_OPEN_CREATE, is used to indicate that file should always 1323** be created, and that it is an error if it already exists. 1324** It is <i>not</i> used to indicate the file should be opened 1325** for exclusive access. 1326** 1327** ^At least szOsFile bytes of memory are allocated by SQLite 1328** to hold the [sqlite3_file] structure passed as the third 1329** argument to xOpen. The xOpen method does not have to 1330** allocate the structure; it should just fill it in. Note that 1331** the xOpen method must set the sqlite3_file.pMethods to either 1332** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1333** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1334** element will be valid after xOpen returns regardless of the success 1335** or failure of the xOpen call. 1336** 1337** [[sqlite3_vfs.xAccess]] 1338** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1339** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1340** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1341** to test whether a file is at least readable. The SQLITE_ACCESS_READ 1342** flag is never actually used and is not implemented in the built-in 1343** VFSes of SQLite. The file is named by the second argument and can be a 1344** directory. The xAccess method returns [SQLITE_OK] on success or some 1345** non-zero error code if there is an I/O error or if the name of 1346** the file given in the second argument is illegal. If SQLITE_OK 1347** is returned, then non-zero or zero is written into *pResOut to indicate 1348** whether or not the file is accessible. 1349** 1350** ^SQLite will always allocate at least mxPathname+1 bytes for the 1351** output buffer xFullPathname. The exact size of the output buffer 1352** is also passed as a parameter to both methods. If the output buffer 1353** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1354** handled as a fatal error by SQLite, vfs implementations should endeavor 1355** to prevent this by setting mxPathname to a sufficiently large value. 1356** 1357** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1358** interfaces are not strictly a part of the filesystem, but they are 1359** included in the VFS structure for completeness. 1360** The xRandomness() function attempts to return nBytes bytes 1361** of good-quality randomness into zOut. The return value is 1362** the actual number of bytes of randomness obtained. 1363** The xSleep() method causes the calling thread to sleep for at 1364** least the number of microseconds given. ^The xCurrentTime() 1365** method returns a Julian Day Number for the current date and time as 1366** a floating point value. 1367** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1368** Day Number multiplied by 86400000 (the number of milliseconds in 1369** a 24-hour day). 1370** ^SQLite will use the xCurrentTimeInt64() method to get the current 1371** date and time if that method is available (if iVersion is 2 or 1372** greater and the function pointer is not NULL) and will fall back 1373** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1374** 1375** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1376** are not used by the SQLite core. These optional interfaces are provided 1377** by some VFSes to facilitate testing of the VFS code. By overriding 1378** system calls with functions under its control, a test program can 1379** simulate faults and error conditions that would otherwise be difficult 1380** or impossible to induce. The set of system calls that can be overridden 1381** varies from one VFS to another, and from one version of the same VFS to the 1382** next. Applications that use these interfaces must be prepared for any 1383** or all of these interfaces to be NULL or for their behavior to change 1384** from one release to the next. Applications must not attempt to access 1385** any of these methods if the iVersion of the VFS is less than 3. 1386*/ 1387typedef struct sqlite3_vfs sqlite3_vfs; 1388typedef void (*sqlite3_syscall_ptr)(void); 1389struct sqlite3_vfs { 1390 int iVersion; /* Structure version number (currently 3) */ 1391 int szOsFile; /* Size of subclassed sqlite3_file */ 1392 int mxPathname; /* Maximum file pathname length */ 1393 sqlite3_vfs *pNext; /* Next registered VFS */ 1394 const char *zName; /* Name of this virtual file system */ 1395 void *pAppData; /* Pointer to application-specific data */ 1396 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1397 int flags, int *pOutFlags); 1398 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1399 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1400 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1401 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1402 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1403 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1404 void (*xDlClose)(sqlite3_vfs*, void*); 1405 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1406 int (*xSleep)(sqlite3_vfs*, int microseconds); 1407 int (*xCurrentTime)(sqlite3_vfs*, double*); 1408 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1409 /* 1410 ** The methods above are in version 1 of the sqlite_vfs object 1411 ** definition. Those that follow are added in version 2 or later 1412 */ 1413 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1414 /* 1415 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1416 ** Those below are for version 3 and greater. 1417 */ 1418 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1419 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1420 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1421 /* 1422 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1423 ** New fields may be appended in future versions. The iVersion 1424 ** value will increment whenever this happens. 1425 */ 1426}; 1427 1428/* 1429** CAPI3REF: Flags for the xAccess VFS method 1430** 1431** These integer constants can be used as the third parameter to 1432** the xAccess method of an [sqlite3_vfs] object. They determine 1433** what kind of permissions the xAccess method is looking for. 1434** With SQLITE_ACCESS_EXISTS, the xAccess method 1435** simply checks whether the file exists. 1436** With SQLITE_ACCESS_READWRITE, the xAccess method 1437** checks whether the named directory is both readable and writable 1438** (in other words, if files can be added, removed, and renamed within 1439** the directory). 1440** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1441** [temp_store_directory pragma], though this could change in a future 1442** release of SQLite. 1443** With SQLITE_ACCESS_READ, the xAccess method 1444** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1445** currently unused, though it might be used in a future release of 1446** SQLite. 1447*/ 1448#define SQLITE_ACCESS_EXISTS 0 1449#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1450#define SQLITE_ACCESS_READ 2 /* Unused */ 1451 1452/* 1453** CAPI3REF: Flags for the xShmLock VFS method 1454** 1455** These integer constants define the various locking operations 1456** allowed by the xShmLock method of [sqlite3_io_methods]. The 1457** following are the only legal combinations of flags to the 1458** xShmLock method: 1459** 1460** <ul> 1461** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1462** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1463** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1464** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1465** </ul> 1466** 1467** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1468** was given on the corresponding lock. 1469** 1470** The xShmLock method can transition between unlocked and SHARED or 1471** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1472** and EXCLUSIVE. 1473*/ 1474#define SQLITE_SHM_UNLOCK 1 1475#define SQLITE_SHM_LOCK 2 1476#define SQLITE_SHM_SHARED 4 1477#define SQLITE_SHM_EXCLUSIVE 8 1478 1479/* 1480** CAPI3REF: Maximum xShmLock index 1481** 1482** The xShmLock method on [sqlite3_io_methods] may use values 1483** between 0 and this upper bound as its "offset" argument. 1484** The SQLite core will never attempt to acquire or release a 1485** lock outside of this range 1486*/ 1487#define SQLITE_SHM_NLOCK 8 1488 1489 1490/* 1491** CAPI3REF: Initialize The SQLite Library 1492** 1493** ^The sqlite3_initialize() routine initializes the 1494** SQLite library. ^The sqlite3_shutdown() routine 1495** deallocates any resources that were allocated by sqlite3_initialize(). 1496** These routines are designed to aid in process initialization and 1497** shutdown on embedded systems. Workstation applications using 1498** SQLite normally do not need to invoke either of these routines. 1499** 1500** A call to sqlite3_initialize() is an "effective" call if it is 1501** the first time sqlite3_initialize() is invoked during the lifetime of 1502** the process, or if it is the first time sqlite3_initialize() is invoked 1503** following a call to sqlite3_shutdown(). ^(Only an effective call 1504** of sqlite3_initialize() does any initialization. All other calls 1505** are harmless no-ops.)^ 1506** 1507** A call to sqlite3_shutdown() is an "effective" call if it is the first 1508** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1509** an effective call to sqlite3_shutdown() does any deinitialization. 1510** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1511** 1512** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1513** is not. The sqlite3_shutdown() interface must only be called from a 1514** single thread. All open [database connections] must be closed and all 1515** other SQLite resources must be deallocated prior to invoking 1516** sqlite3_shutdown(). 1517** 1518** Among other things, ^sqlite3_initialize() will invoke 1519** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1520** will invoke sqlite3_os_end(). 1521** 1522** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1523** ^If for some reason, sqlite3_initialize() is unable to initialize 1524** the library (perhaps it is unable to allocate a needed resource such 1525** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1526** 1527** ^The sqlite3_initialize() routine is called internally by many other 1528** SQLite interfaces so that an application usually does not need to 1529** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1530** calls sqlite3_initialize() so the SQLite library will be automatically 1531** initialized when [sqlite3_open()] is called if it has not be initialized 1532** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1533** compile-time option, then the automatic calls to sqlite3_initialize() 1534** are omitted and the application must call sqlite3_initialize() directly 1535** prior to using any other SQLite interface. For maximum portability, 1536** it is recommended that applications always invoke sqlite3_initialize() 1537** directly prior to using any other SQLite interface. Future releases 1538** of SQLite may require this. In other words, the behavior exhibited 1539** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1540** default behavior in some future release of SQLite. 1541** 1542** The sqlite3_os_init() routine does operating-system specific 1543** initialization of the SQLite library. The sqlite3_os_end() 1544** routine undoes the effect of sqlite3_os_init(). Typical tasks 1545** performed by these routines include allocation or deallocation 1546** of static resources, initialization of global variables, 1547** setting up a default [sqlite3_vfs] module, or setting up 1548** a default configuration using [sqlite3_config()]. 1549** 1550** The application should never invoke either sqlite3_os_init() 1551** or sqlite3_os_end() directly. The application should only invoke 1552** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1553** interface is called automatically by sqlite3_initialize() and 1554** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1555** implementations for sqlite3_os_init() and sqlite3_os_end() 1556** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1557** When [custom builds | built for other platforms] 1558** (using the [SQLITE_OS_OTHER=1] compile-time 1559** option) the application must supply a suitable implementation for 1560** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1561** implementation of sqlite3_os_init() or sqlite3_os_end() 1562** must return [SQLITE_OK] on success and some other [error code] upon 1563** failure. 1564*/ 1565int sqlite3_initialize(void); 1566int sqlite3_shutdown(void); 1567int sqlite3_os_init(void); 1568int sqlite3_os_end(void); 1569 1570/* 1571** CAPI3REF: Configuring The SQLite Library 1572** 1573** The sqlite3_config() interface is used to make global configuration 1574** changes to SQLite in order to tune SQLite to the specific needs of 1575** the application. The default configuration is recommended for most 1576** applications and so this routine is usually not necessary. It is 1577** provided to support rare applications with unusual needs. 1578** 1579** <b>The sqlite3_config() interface is not threadsafe. The application 1580** must ensure that no other SQLite interfaces are invoked by other 1581** threads while sqlite3_config() is running.</b> 1582** 1583** The sqlite3_config() interface 1584** may only be invoked prior to library initialization using 1585** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1586** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1587** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1588** Note, however, that ^sqlite3_config() can be called as part of the 1589** implementation of an application-defined [sqlite3_os_init()]. 1590** 1591** The first argument to sqlite3_config() is an integer 1592** [configuration option] that determines 1593** what property of SQLite is to be configured. Subsequent arguments 1594** vary depending on the [configuration option] 1595** in the first argument. 1596** 1597** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1598** ^If the option is unknown or SQLite is unable to set the option 1599** then this routine returns a non-zero [error code]. 1600*/ 1601int sqlite3_config(int, ...); 1602 1603/* 1604** CAPI3REF: Configure database connections 1605** METHOD: sqlite3 1606** 1607** The sqlite3_db_config() interface is used to make configuration 1608** changes to a [database connection]. The interface is similar to 1609** [sqlite3_config()] except that the changes apply to a single 1610** [database connection] (specified in the first argument). 1611** 1612** The second argument to sqlite3_db_config(D,V,...) is the 1613** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1614** that indicates what aspect of the [database connection] is being configured. 1615** Subsequent arguments vary depending on the configuration verb. 1616** 1617** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1618** the call is considered successful. 1619*/ 1620int sqlite3_db_config(sqlite3*, int op, ...); 1621 1622/* 1623** CAPI3REF: Memory Allocation Routines 1624** 1625** An instance of this object defines the interface between SQLite 1626** and low-level memory allocation routines. 1627** 1628** This object is used in only one place in the SQLite interface. 1629** A pointer to an instance of this object is the argument to 1630** [sqlite3_config()] when the configuration option is 1631** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1632** By creating an instance of this object 1633** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1634** during configuration, an application can specify an alternative 1635** memory allocation subsystem for SQLite to use for all of its 1636** dynamic memory needs. 1637** 1638** Note that SQLite comes with several [built-in memory allocators] 1639** that are perfectly adequate for the overwhelming majority of applications 1640** and that this object is only useful to a tiny minority of applications 1641** with specialized memory allocation requirements. This object is 1642** also used during testing of SQLite in order to specify an alternative 1643** memory allocator that simulates memory out-of-memory conditions in 1644** order to verify that SQLite recovers gracefully from such 1645** conditions. 1646** 1647** The xMalloc, xRealloc, and xFree methods must work like the 1648** malloc(), realloc() and free() functions from the standard C library. 1649** ^SQLite guarantees that the second argument to 1650** xRealloc is always a value returned by a prior call to xRoundup. 1651** 1652** xSize should return the allocated size of a memory allocation 1653** previously obtained from xMalloc or xRealloc. The allocated size 1654** is always at least as big as the requested size but may be larger. 1655** 1656** The xRoundup method returns what would be the allocated size of 1657** a memory allocation given a particular requested size. Most memory 1658** allocators round up memory allocations at least to the next multiple 1659** of 8. Some allocators round up to a larger multiple or to a power of 2. 1660** Every memory allocation request coming in through [sqlite3_malloc()] 1661** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1662** that causes the corresponding memory allocation to fail. 1663** 1664** The xInit method initializes the memory allocator. For example, 1665** it might allocate any required mutexes or initialize internal data 1666** structures. The xShutdown method is invoked (indirectly) by 1667** [sqlite3_shutdown()] and should deallocate any resources acquired 1668** by xInit. The pAppData pointer is used as the only parameter to 1669** xInit and xShutdown. 1670** 1671** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes 1672** the xInit method, so the xInit method need not be threadsafe. The 1673** xShutdown method is only called from [sqlite3_shutdown()] so it does 1674** not need to be threadsafe either. For all other methods, SQLite 1675** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1676** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1677** it is by default) and so the methods are automatically serialized. 1678** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1679** methods must be threadsafe or else make their own arrangements for 1680** serialization. 1681** 1682** SQLite will never invoke xInit() more than once without an intervening 1683** call to xShutdown(). 1684*/ 1685typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1686struct sqlite3_mem_methods { 1687 void *(*xMalloc)(int); /* Memory allocation function */ 1688 void (*xFree)(void*); /* Free a prior allocation */ 1689 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1690 int (*xSize)(void*); /* Return the size of an allocation */ 1691 int (*xRoundup)(int); /* Round up request size to allocation size */ 1692 int (*xInit)(void*); /* Initialize the memory allocator */ 1693 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1694 void *pAppData; /* Argument to xInit() and xShutdown() */ 1695}; 1696 1697/* 1698** CAPI3REF: Configuration Options 1699** KEYWORDS: {configuration option} 1700** 1701** These constants are the available integer configuration options that 1702** can be passed as the first argument to the [sqlite3_config()] interface. 1703** 1704** New configuration options may be added in future releases of SQLite. 1705** Existing configuration options might be discontinued. Applications 1706** should check the return code from [sqlite3_config()] to make sure that 1707** the call worked. The [sqlite3_config()] interface will return a 1708** non-zero [error code] if a discontinued or unsupported configuration option 1709** is invoked. 1710** 1711** <dl> 1712** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1713** <dd>There are no arguments to this option. ^This option sets the 1714** [threading mode] to Single-thread. In other words, it disables 1715** all mutexing and puts SQLite into a mode where it can only be used 1716** by a single thread. ^If SQLite is compiled with 1717** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1718** it is not possible to change the [threading mode] from its default 1719** value of Single-thread and so [sqlite3_config()] will return 1720** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1721** configuration option.</dd> 1722** 1723** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1724** <dd>There are no arguments to this option. ^This option sets the 1725** [threading mode] to Multi-thread. In other words, it disables 1726** mutexing on [database connection] and [prepared statement] objects. 1727** The application is responsible for serializing access to 1728** [database connections] and [prepared statements]. But other mutexes 1729** are enabled so that SQLite will be safe to use in a multi-threaded 1730** environment as long as no two threads attempt to use the same 1731** [database connection] at the same time. ^If SQLite is compiled with 1732** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1733** it is not possible to set the Multi-thread [threading mode] and 1734** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1735** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1736** 1737** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1738** <dd>There are no arguments to this option. ^This option sets the 1739** [threading mode] to Serialized. In other words, this option enables 1740** all mutexes including the recursive 1741** mutexes on [database connection] and [prepared statement] objects. 1742** In this mode (which is the default when SQLite is compiled with 1743** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1744** to [database connections] and [prepared statements] so that the 1745** application is free to use the same [database connection] or the 1746** same [prepared statement] in different threads at the same time. 1747** ^If SQLite is compiled with 1748** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1749** it is not possible to set the Serialized [threading mode] and 1750** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1751** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1752** 1753** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1754** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1755** a pointer to an instance of the [sqlite3_mem_methods] structure. 1756** The argument specifies 1757** alternative low-level memory allocation routines to be used in place of 1758** the memory allocation routines built into SQLite.)^ ^SQLite makes 1759** its own private copy of the content of the [sqlite3_mem_methods] structure 1760** before the [sqlite3_config()] call returns.</dd> 1761** 1762** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1763** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1764** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1765** The [sqlite3_mem_methods] 1766** structure is filled with the currently defined memory allocation routines.)^ 1767** This option can be used to overload the default memory allocation 1768** routines with a wrapper that simulations memory allocation failure or 1769** tracks memory usage, for example. </dd> 1770** 1771** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1772** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1773** type int, interpreted as a boolean, which if true provides a hint to 1774** SQLite that it should avoid large memory allocations if possible. 1775** SQLite will run faster if it is free to make large memory allocations, 1776** but some application might prefer to run slower in exchange for 1777** guarantees about memory fragmentation that are possible if large 1778** allocations are avoided. This hint is normally off. 1779** </dd> 1780** 1781** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1782** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1783** interpreted as a boolean, which enables or disables the collection of 1784** memory allocation statistics. ^(When memory allocation statistics are 1785** disabled, the following SQLite interfaces become non-operational: 1786** <ul> 1787** <li> [sqlite3_hard_heap_limit64()] 1788** <li> [sqlite3_memory_used()] 1789** <li> [sqlite3_memory_highwater()] 1790** <li> [sqlite3_soft_heap_limit64()] 1791** <li> [sqlite3_status64()] 1792** </ul>)^ 1793** ^Memory allocation statistics are enabled by default unless SQLite is 1794** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1795** allocation statistics are disabled by default. 1796** </dd> 1797** 1798** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1799** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1800** </dd> 1801** 1802** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1803** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1804** that SQLite can use for the database page cache with the default page 1805** cache implementation. 1806** This configuration option is a no-op if an application-defined page 1807** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1808** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1809** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1810** and the number of cache lines (N). 1811** The sz argument should be the size of the largest database page 1812** (a power of two between 512 and 65536) plus some extra bytes for each 1813** page header. ^The number of extra bytes needed by the page header 1814** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1815** ^It is harmless, apart from the wasted memory, 1816** for the sz parameter to be larger than necessary. The pMem 1817** argument must be either a NULL pointer or a pointer to an 8-byte 1818** aligned block of memory of at least sz*N bytes, otherwise 1819** subsequent behavior is undefined. 1820** ^When pMem is not NULL, SQLite will strive to use the memory provided 1821** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1822** a page cache line is larger than sz bytes or if all of the pMem buffer 1823** is exhausted. 1824** ^If pMem is NULL and N is non-zero, then each database connection 1825** does an initial bulk allocation for page cache memory 1826** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1827** of -1024*N bytes if N is negative, . ^If additional 1828** page cache memory is needed beyond what is provided by the initial 1829** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1830** additional cache line. </dd> 1831** 1832** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1833** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1834** that SQLite will use for all of its dynamic memory allocation needs 1835** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1836** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1837** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1838** [SQLITE_ERROR] if invoked otherwise. 1839** ^There are three arguments to SQLITE_CONFIG_HEAP: 1840** An 8-byte aligned pointer to the memory, 1841** the number of bytes in the memory buffer, and the minimum allocation size. 1842** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1843** to using its default memory allocator (the system malloc() implementation), 1844** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1845** memory pointer is not NULL then the alternative memory 1846** allocator is engaged to handle all of SQLites memory allocation needs. 1847** The first pointer (the memory pointer) must be aligned to an 8-byte 1848** boundary or subsequent behavior of SQLite will be undefined. 1849** The minimum allocation size is capped at 2**12. Reasonable values 1850** for the minimum allocation size are 2**5 through 2**8.</dd> 1851** 1852** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1853** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1854** pointer to an instance of the [sqlite3_mutex_methods] structure. 1855** The argument specifies alternative low-level mutex routines to be used 1856** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1857** the content of the [sqlite3_mutex_methods] structure before the call to 1858** [sqlite3_config()] returns. ^If SQLite is compiled with 1859** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1860** the entire mutexing subsystem is omitted from the build and hence calls to 1861** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1862** return [SQLITE_ERROR].</dd> 1863** 1864** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1865** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1866** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1867** [sqlite3_mutex_methods] 1868** structure is filled with the currently defined mutex routines.)^ 1869** This option can be used to overload the default mutex allocation 1870** routines with a wrapper used to track mutex usage for performance 1871** profiling or testing, for example. ^If SQLite is compiled with 1872** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1873** the entire mutexing subsystem is omitted from the build and hence calls to 1874** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1875** return [SQLITE_ERROR].</dd> 1876** 1877** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1878** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1879** the default size of lookaside memory on each [database connection]. 1880** The first argument is the 1881** size of each lookaside buffer slot and the second is the number of 1882** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1883** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1884** option to [sqlite3_db_config()] can be used to change the lookaside 1885** configuration on individual connections.)^ </dd> 1886** 1887** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1888** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1889** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1890** the interface to a custom page cache implementation.)^ 1891** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1892** 1893** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1894** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1895** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1896** the current page cache implementation into that object.)^ </dd> 1897** 1898** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1899** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1900** global [error log]. 1901** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1902** function with a call signature of void(*)(void*,int,const char*), 1903** and a pointer to void. ^If the function pointer is not NULL, it is 1904** invoked by [sqlite3_log()] to process each logging event. ^If the 1905** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1906** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1907** passed through as the first parameter to the application-defined logger 1908** function whenever that function is invoked. ^The second parameter to 1909** the logger function is a copy of the first parameter to the corresponding 1910** [sqlite3_log()] call and is intended to be a [result code] or an 1911** [extended result code]. ^The third parameter passed to the logger is 1912** log message after formatting via [sqlite3_snprintf()]. 1913** The SQLite logging interface is not reentrant; the logger function 1914** supplied by the application must not invoke any SQLite interface. 1915** In a multi-threaded application, the application-defined logger 1916** function must be threadsafe. </dd> 1917** 1918** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1919** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1920** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1921** then URI handling is globally disabled.)^ ^If URI handling is globally 1922** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1923** [sqlite3_open16()] or 1924** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1925** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1926** connection is opened. ^If it is globally disabled, filenames are 1927** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1928** database connection is opened. ^(By default, URI handling is globally 1929** disabled. The default value may be changed by compiling with the 1930** [SQLITE_USE_URI] symbol defined.)^ 1931** 1932** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1933** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1934** argument which is interpreted as a boolean in order to enable or disable 1935** the use of covering indices for full table scans in the query optimizer. 1936** ^The default setting is determined 1937** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1938** if that compile-time option is omitted. 1939** The ability to disable the use of covering indices for full table scans 1940** is because some incorrectly coded legacy applications might malfunction 1941** when the optimization is enabled. Providing the ability to 1942** disable the optimization allows the older, buggy application code to work 1943** without change even with newer versions of SQLite. 1944** 1945** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1946** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1947** <dd> These options are obsolete and should not be used by new code. 1948** They are retained for backwards compatibility but are now no-ops. 1949** </dd> 1950** 1951** [[SQLITE_CONFIG_SQLLOG]] 1952** <dt>SQLITE_CONFIG_SQLLOG 1953** <dd>This option is only available if sqlite is compiled with the 1954** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1955** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1956** The second should be of type (void*). The callback is invoked by the library 1957** in three separate circumstances, identified by the value passed as the 1958** fourth parameter. If the fourth parameter is 0, then the database connection 1959** passed as the second argument has just been opened. The third argument 1960** points to a buffer containing the name of the main database file. If the 1961** fourth parameter is 1, then the SQL statement that the third parameter 1962** points to has just been executed. Or, if the fourth parameter is 2, then 1963** the connection being passed as the second parameter is being closed. The 1964** third parameter is passed NULL In this case. An example of using this 1965** configuration option can be seen in the "test_sqllog.c" source file in 1966** the canonical SQLite source tree.</dd> 1967** 1968** [[SQLITE_CONFIG_MMAP_SIZE]] 1969** <dt>SQLITE_CONFIG_MMAP_SIZE 1970** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1971** that are the default mmap size limit (the default setting for 1972** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1973** ^The default setting can be overridden by each database connection using 1974** either the [PRAGMA mmap_size] command, or by using the 1975** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1976** will be silently truncated if necessary so that it does not exceed the 1977** compile-time maximum mmap size set by the 1978** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1979** ^If either argument to this option is negative, then that argument is 1980** changed to its compile-time default. 1981** 1982** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1983** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1984** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1985** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1986** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1987** that specifies the maximum size of the created heap. 1988** 1989** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1990** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1991** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1992** is a pointer to an integer and writes into that integer the number of extra 1993** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1994** The amount of extra space required can change depending on the compiler, 1995** target platform, and SQLite version. 1996** 1997** [[SQLITE_CONFIG_PMASZ]] 1998** <dt>SQLITE_CONFIG_PMASZ 1999** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 2000** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 2001** sorter to that integer. The default minimum PMA Size is set by the 2002** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 2003** to help with sort operations when multithreaded sorting 2004** is enabled (using the [PRAGMA threads] command) and the amount of content 2005** to be sorted exceeds the page size times the minimum of the 2006** [PRAGMA cache_size] setting and this value. 2007** 2008** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 2009** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 2010** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 2011** becomes the [statement journal] spill-to-disk threshold. 2012** [Statement journals] are held in memory until their size (in bytes) 2013** exceeds this threshold, at which point they are written to disk. 2014** Or if the threshold is -1, statement journals are always held 2015** exclusively in memory. 2016** Since many statement journals never become large, setting the spill 2017** threshold to a value such as 64KiB can greatly reduce the amount of 2018** I/O required to support statement rollback. 2019** The default value for this setting is controlled by the 2020** [SQLITE_STMTJRNL_SPILL] compile-time option. 2021** 2022** [[SQLITE_CONFIG_SORTERREF_SIZE]] 2023** <dt>SQLITE_CONFIG_SORTERREF_SIZE 2024** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter 2025** of type (int) - the new value of the sorter-reference size threshold. 2026** Usually, when SQLite uses an external sort to order records according 2027** to an ORDER BY clause, all fields required by the caller are present in the 2028** sorted records. However, if SQLite determines based on the declared type 2029** of a table column that its values are likely to be very large - larger 2030** than the configured sorter-reference size threshold - then a reference 2031** is stored in each sorted record and the required column values loaded 2032** from the database as records are returned in sorted order. The default 2033** value for this option is to never use this optimization. Specifying a 2034** negative value for this option restores the default behaviour. 2035** This option is only available if SQLite is compiled with the 2036** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option. 2037** 2038** [[SQLITE_CONFIG_MEMDB_MAXSIZE]] 2039** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE 2040** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter 2041** [sqlite3_int64] parameter which is the default maximum size for an in-memory 2042** database created using [sqlite3_deserialize()]. This default maximum 2043** size can be adjusted up or down for individual databases using the 2044** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control]. If this 2045** configuration setting is never used, then the default maximum is determined 2046** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option. If that 2047** compile-time option is not set, then the default maximum is 1073741824. 2048** </dl> 2049*/ 2050#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 2051#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 2052#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 2053#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 2054#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 2055#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 2056#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 2057#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 2058#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 2059#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 2060#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 2061/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 2062#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 2063#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 2064#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 2065#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 2066#define SQLITE_CONFIG_URI 17 /* int */ 2067#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 2068#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 2069#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 2070#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 2071#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 2072#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 2073#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 2074#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 2075#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 2076#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 2077#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */ 2078#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */ 2079 2080/* 2081** CAPI3REF: Database Connection Configuration Options 2082** 2083** These constants are the available integer configuration options that 2084** can be passed as the second argument to the [sqlite3_db_config()] interface. 2085** 2086** New configuration options may be added in future releases of SQLite. 2087** Existing configuration options might be discontinued. Applications 2088** should check the return code from [sqlite3_db_config()] to make sure that 2089** the call worked. ^The [sqlite3_db_config()] interface will return a 2090** non-zero [error code] if a discontinued or unsupported configuration option 2091** is invoked. 2092** 2093** <dl> 2094** [[SQLITE_DBCONFIG_LOOKASIDE]] 2095** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 2096** <dd> ^This option takes three additional arguments that determine the 2097** [lookaside memory allocator] configuration for the [database connection]. 2098** ^The first argument (the third parameter to [sqlite3_db_config()] is a 2099** pointer to a memory buffer to use for lookaside memory. 2100** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 2101** may be NULL in which case SQLite will allocate the 2102** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 2103** size of each lookaside buffer slot. ^The third argument is the number of 2104** slots. The size of the buffer in the first argument must be greater than 2105** or equal to the product of the second and third arguments. The buffer 2106** must be aligned to an 8-byte boundary. ^If the second argument to 2107** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 2108** rounded down to the next smaller multiple of 8. ^(The lookaside memory 2109** configuration for a database connection can only be changed when that 2110** connection is not currently using lookaside memory, or in other words 2111** when the "current value" returned by 2112** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 2113** Any attempt to change the lookaside memory configuration when lookaside 2114** memory is in use leaves the configuration unchanged and returns 2115** [SQLITE_BUSY].)^</dd> 2116** 2117** [[SQLITE_DBCONFIG_ENABLE_FKEY]] 2118** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 2119** <dd> ^This option is used to enable or disable the enforcement of 2120** [foreign key constraints]. There should be two additional arguments. 2121** The first argument is an integer which is 0 to disable FK enforcement, 2122** positive to enable FK enforcement or negative to leave FK enforcement 2123** unchanged. The second parameter is a pointer to an integer into which 2124** is written 0 or 1 to indicate whether FK enforcement is off or on 2125** following this call. The second parameter may be a NULL pointer, in 2126** which case the FK enforcement setting is not reported back. </dd> 2127** 2128** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]] 2129** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2130** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2131** There should be two additional arguments. 2132** The first argument is an integer which is 0 to disable triggers, 2133** positive to enable triggers or negative to leave the setting unchanged. 2134** The second parameter is a pointer to an integer into which 2135** is written 0 or 1 to indicate whether triggers are disabled or enabled 2136** following this call. The second parameter may be a NULL pointer, in 2137** which case the trigger setting is not reported back. 2138** 2139** <p>Originally this option disabled all triggers. ^(However, since 2140** SQLite version 3.35.0, TEMP triggers are still allowed even if 2141** this option is off. So, in other words, this option now only disables 2142** triggers in the main database schema or in the schemas of ATTACH-ed 2143** databases.)^ </dd> 2144** 2145** [[SQLITE_DBCONFIG_ENABLE_VIEW]] 2146** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt> 2147** <dd> ^This option is used to enable or disable [CREATE VIEW | views]. 2148** There should be two additional arguments. 2149** The first argument is an integer which is 0 to disable views, 2150** positive to enable views or negative to leave the setting unchanged. 2151** The second parameter is a pointer to an integer into which 2152** is written 0 or 1 to indicate whether views are disabled or enabled 2153** following this call. The second parameter may be a NULL pointer, in 2154** which case the view setting is not reported back. 2155** 2156** <p>Originally this option disabled all views. ^(However, since 2157** SQLite version 3.35.0, TEMP views are still allowed even if 2158** this option is off. So, in other words, this option now only disables 2159** views in the main database schema or in the schemas of ATTACH-ed 2160** databases.)^ </dd> 2161** 2162** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]] 2163** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2164** <dd> ^This option is used to enable or disable the 2165** [fts3_tokenizer()] function which is part of the 2166** [FTS3] full-text search engine extension. 2167** There should be two additional arguments. 2168** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2169** positive to enable fts3_tokenizer() or negative to leave the setting 2170** unchanged. 2171** The second parameter is a pointer to an integer into which 2172** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2173** following this call. The second parameter may be a NULL pointer, in 2174** which case the new setting is not reported back. </dd> 2175** 2176** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]] 2177** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2178** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2179** interface independently of the [load_extension()] SQL function. 2180** The [sqlite3_enable_load_extension()] API enables or disables both the 2181** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2182** There should be two additional arguments. 2183** When the first argument to this interface is 1, then only the C-API is 2184** enabled and the SQL function remains disabled. If the first argument to 2185** this interface is 0, then both the C-API and the SQL function are disabled. 2186** If the first argument is -1, then no changes are made to state of either the 2187** C-API or the SQL function. 2188** The second parameter is a pointer to an integer into which 2189** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2190** is disabled or enabled following this call. The second parameter may 2191** be a NULL pointer, in which case the new setting is not reported back. 2192** </dd> 2193** 2194** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2195** <dd> ^This option is used to change the name of the "main" database 2196** schema. ^The sole argument is a pointer to a constant UTF8 string 2197** which will become the new schema name in place of "main". ^SQLite 2198** does not make a copy of the new main schema name string, so the application 2199** must ensure that the argument passed into this DBCONFIG option is unchanged 2200** until after the database connection closes. 2201** </dd> 2202** 2203** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]] 2204** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2205** <dd> Usually, when a database in wal mode is closed or detached from a 2206** database handle, SQLite checks if this will mean that there are now no 2207** connections at all to the database. If so, it performs a checkpoint 2208** operation before closing the connection. This option may be used to 2209** override this behaviour. The first parameter passed to this operation 2210** is an integer - positive to disable checkpoints-on-close, or zero (the 2211** default) to enable them, and negative to leave the setting unchanged. 2212** The second parameter is a pointer to an integer 2213** into which is written 0 or 1 to indicate whether checkpoints-on-close 2214** have been disabled - 0 if they are not disabled, 1 if they are. 2215** </dd> 2216** 2217** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2218** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2219** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2220** a single SQL query statement will always use the same algorithm regardless 2221** of values of [bound parameters].)^ The QPSG disables some query optimizations 2222** that look at the values of bound parameters, which can make some queries 2223** slower. But the QPSG has the advantage of more predictable behavior. With 2224** the QPSG active, SQLite will always use the same query plan in the field as 2225** was used during testing in the lab. 2226** The first argument to this setting is an integer which is 0 to disable 2227** the QPSG, positive to enable QPSG, or negative to leave the setting 2228** unchanged. The second parameter is a pointer to an integer into which 2229** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2230** following this call. 2231** </dd> 2232** 2233** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2234** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2235** include output for any operations performed by trigger programs. This 2236** option is used to set or clear (the default) a flag that governs this 2237** behavior. The first parameter passed to this operation is an integer - 2238** positive to enable output for trigger programs, or zero to disable it, 2239** or negative to leave the setting unchanged. 2240** The second parameter is a pointer to an integer into which is written 2241** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2242** it is not disabled, 1 if it is. 2243** </dd> 2244** 2245** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt> 2246** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run 2247** [VACUUM] in order to reset a database back to an empty database 2248** with no schema and no content. The following process works even for 2249** a badly corrupted database file: 2250** <ol> 2251** <li> If the database connection is newly opened, make sure it has read the 2252** database schema by preparing then discarding some query against the 2253** database, or calling sqlite3_table_column_metadata(), ignoring any 2254** errors. This step is only necessary if the application desires to keep 2255** the database in WAL mode after the reset if it was in WAL mode before 2256** the reset. 2257** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0); 2258** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0); 2259** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0); 2260** </ol> 2261** Because resetting a database is destructive and irreversible, the 2262** process requires the use of this obscure API and multiple steps to help 2263** ensure that it does not happen by accident. 2264** 2265** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt> 2266** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the 2267** "defensive" flag for a database connection. When the defensive 2268** flag is enabled, language features that allow ordinary SQL to 2269** deliberately corrupt the database file are disabled. The disabled 2270** features include but are not limited to the following: 2271** <ul> 2272** <li> The [PRAGMA writable_schema=ON] statement. 2273** <li> The [PRAGMA journal_mode=OFF] statement. 2274** <li> Writes to the [sqlite_dbpage] virtual table. 2275** <li> Direct writes to [shadow tables]. 2276** </ul> 2277** </dd> 2278** 2279** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt> 2280** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the 2281** "writable_schema" flag. This has the same effect and is logically equivalent 2282** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF]. 2283** The first argument to this setting is an integer which is 0 to disable 2284** the writable_schema, positive to enable writable_schema, or negative to 2285** leave the setting unchanged. The second parameter is a pointer to an 2286** integer into which is written 0 or 1 to indicate whether the writable_schema 2287** is enabled or disabled following this call. 2288** </dd> 2289** 2290** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]] 2291** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt> 2292** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates 2293** the legacy behavior of the [ALTER TABLE RENAME] command such it 2294** behaves as it did prior to [version 3.24.0] (2018-06-04). See the 2295** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for 2296** additional information. This feature can also be turned on and off 2297** using the [PRAGMA legacy_alter_table] statement. 2298** </dd> 2299** 2300** [[SQLITE_DBCONFIG_DQS_DML]] 2301** <dt>SQLITE_DBCONFIG_DQS_DML</td> 2302** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates 2303** the legacy [double-quoted string literal] misfeature for DML statements 2304** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The 2305** default value of this setting is determined by the [-DSQLITE_DQS] 2306** compile-time option. 2307** </dd> 2308** 2309** [[SQLITE_DBCONFIG_DQS_DDL]] 2310** <dt>SQLITE_DBCONFIG_DQS_DDL</td> 2311** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates 2312** the legacy [double-quoted string literal] misfeature for DDL statements, 2313** such as CREATE TABLE and CREATE INDEX. The 2314** default value of this setting is determined by the [-DSQLITE_DQS] 2315** compile-time option. 2316** </dd> 2317** 2318** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]] 2319** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td> 2320** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to 2321** assume that database schemas are untainted by malicious content. 2322** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite 2323** takes additional defensive steps to protect the application from harm 2324** including: 2325** <ul> 2326** <li> Prohibit the use of SQL functions inside triggers, views, 2327** CHECK constraints, DEFAULT clauses, expression indexes, 2328** partial indexes, or generated columns 2329** unless those functions are tagged with [SQLITE_INNOCUOUS]. 2330** <li> Prohibit the use of virtual tables inside of triggers or views 2331** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS]. 2332** </ul> 2333** This setting defaults to "on" for legacy compatibility, however 2334** all applications are advised to turn it off if possible. This setting 2335** can also be controlled using the [PRAGMA trusted_schema] statement. 2336** </dd> 2337** 2338** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]] 2339** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td> 2340** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates 2341** the legacy file format flag. When activated, this flag causes all newly 2342** created database file to have a schema format version number (the 4-byte 2343** integer found at offset 44 into the database header) of 1. This in turn 2344** means that the resulting database file will be readable and writable by 2345** any SQLite version back to 3.0.0 ([dateof:3.0.0]). Without this setting, 2346** newly created databases are generally not understandable by SQLite versions 2347** prior to 3.3.0 ([dateof:3.3.0]). As these words are written, there 2348** is now scarcely any need to generated database files that are compatible 2349** all the way back to version 3.0.0, and so this setting is of little 2350** practical use, but is provided so that SQLite can continue to claim the 2351** ability to generate new database files that are compatible with version 2352** 3.0.0. 2353** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on, 2354** the [VACUUM] command will fail with an obscure error when attempting to 2355** process a table with generated columns and a descending index. This is 2356** not considered a bug since SQLite versions 3.3.0 and earlier do not support 2357** either generated columns or decending indexes. 2358** </dd> 2359** </dl> 2360*/ 2361#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2362#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2363#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2364#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2365#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2366#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2367#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2368#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2369#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2370#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */ 2371#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */ 2372#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */ 2373#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */ 2374#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */ 2375#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */ 2376#define SQLITE_DBCONFIG_ENABLE_VIEW 1015 /* int int* */ 2377#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT 1016 /* int int* */ 2378#define SQLITE_DBCONFIG_TRUSTED_SCHEMA 1017 /* int int* */ 2379#define SQLITE_DBCONFIG_MAX 1017 /* Largest DBCONFIG */ 2380 2381/* 2382** CAPI3REF: Enable Or Disable Extended Result Codes 2383** METHOD: sqlite3 2384** 2385** ^The sqlite3_extended_result_codes() routine enables or disables the 2386** [extended result codes] feature of SQLite. ^The extended result 2387** codes are disabled by default for historical compatibility. 2388*/ 2389int sqlite3_extended_result_codes(sqlite3*, int onoff); 2390 2391/* 2392** CAPI3REF: Last Insert Rowid 2393** METHOD: sqlite3 2394** 2395** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2396** has a unique 64-bit signed 2397** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2398** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2399** names are not also used by explicitly declared columns. ^If 2400** the table has a column of type [INTEGER PRIMARY KEY] then that column 2401** is another alias for the rowid. 2402** 2403** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2404** the most recent successful [INSERT] into a rowid table or [virtual table] 2405** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2406** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2407** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2408** zero. 2409** 2410** As well as being set automatically as rows are inserted into database 2411** tables, the value returned by this function may be set explicitly by 2412** [sqlite3_set_last_insert_rowid()] 2413** 2414** Some virtual table implementations may INSERT rows into rowid tables as 2415** part of committing a transaction (e.g. to flush data accumulated in memory 2416** to disk). In this case subsequent calls to this function return the rowid 2417** associated with these internal INSERT operations, which leads to 2418** unintuitive results. Virtual table implementations that do write to rowid 2419** tables in this way can avoid this problem by restoring the original 2420** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2421** control to the user. 2422** 2423** ^(If an [INSERT] occurs within a trigger then this routine will 2424** return the [rowid] of the inserted row as long as the trigger is 2425** running. Once the trigger program ends, the value returned 2426** by this routine reverts to what it was before the trigger was fired.)^ 2427** 2428** ^An [INSERT] that fails due to a constraint violation is not a 2429** successful [INSERT] and does not change the value returned by this 2430** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2431** and INSERT OR ABORT make no changes to the return value of this 2432** routine when their insertion fails. ^(When INSERT OR REPLACE 2433** encounters a constraint violation, it does not fail. The 2434** INSERT continues to completion after deleting rows that caused 2435** the constraint problem so INSERT OR REPLACE will always change 2436** the return value of this interface.)^ 2437** 2438** ^For the purposes of this routine, an [INSERT] is considered to 2439** be successful even if it is subsequently rolled back. 2440** 2441** This function is accessible to SQL statements via the 2442** [last_insert_rowid() SQL function]. 2443** 2444** If a separate thread performs a new [INSERT] on the same 2445** database connection while the [sqlite3_last_insert_rowid()] 2446** function is running and thus changes the last insert [rowid], 2447** then the value returned by [sqlite3_last_insert_rowid()] is 2448** unpredictable and might not equal either the old or the new 2449** last insert [rowid]. 2450*/ 2451sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2452 2453/* 2454** CAPI3REF: Set the Last Insert Rowid value. 2455** METHOD: sqlite3 2456** 2457** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2458** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2459** without inserting a row into the database. 2460*/ 2461void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2462 2463/* 2464** CAPI3REF: Count The Number Of Rows Modified 2465** METHOD: sqlite3 2466** 2467** ^This function returns the number of rows modified, inserted or 2468** deleted by the most recently completed INSERT, UPDATE or DELETE 2469** statement on the database connection specified by the only parameter. 2470** ^Executing any other type of SQL statement does not modify the value 2471** returned by this function. 2472** 2473** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2474** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2475** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2476** 2477** Changes to a view that are intercepted by 2478** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2479** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2480** DELETE statement run on a view is always zero. Only changes made to real 2481** tables are counted. 2482** 2483** Things are more complicated if the sqlite3_changes() function is 2484** executed while a trigger program is running. This may happen if the 2485** program uses the [changes() SQL function], or if some other callback 2486** function invokes sqlite3_changes() directly. Essentially: 2487** 2488** <ul> 2489** <li> ^(Before entering a trigger program the value returned by 2490** sqlite3_changes() function is saved. After the trigger program 2491** has finished, the original value is restored.)^ 2492** 2493** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2494** statement sets the value returned by sqlite3_changes() 2495** upon completion as normal. Of course, this value will not include 2496** any changes performed by sub-triggers, as the sqlite3_changes() 2497** value will be saved and restored after each sub-trigger has run.)^ 2498** </ul> 2499** 2500** ^This means that if the changes() SQL function (or similar) is used 2501** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2502** returns the value as set when the calling statement began executing. 2503** ^If it is used by the second or subsequent such statement within a trigger 2504** program, the value returned reflects the number of rows modified by the 2505** previous INSERT, UPDATE or DELETE statement within the same trigger. 2506** 2507** If a separate thread makes changes on the same database connection 2508** while [sqlite3_changes()] is running then the value returned 2509** is unpredictable and not meaningful. 2510** 2511** See also: 2512** <ul> 2513** <li> the [sqlite3_total_changes()] interface 2514** <li> the [count_changes pragma] 2515** <li> the [changes() SQL function] 2516** <li> the [data_version pragma] 2517** </ul> 2518*/ 2519int sqlite3_changes(sqlite3*); 2520 2521/* 2522** CAPI3REF: Total Number Of Rows Modified 2523** METHOD: sqlite3 2524** 2525** ^This function returns the total number of rows inserted, modified or 2526** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2527** since the database connection was opened, including those executed as 2528** part of trigger programs. ^Executing any other type of SQL statement 2529** does not affect the value returned by sqlite3_total_changes(). 2530** 2531** ^Changes made as part of [foreign key actions] are included in the 2532** count, but those made as part of REPLACE constraint resolution are 2533** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2534** are not counted. 2535** 2536** The [sqlite3_total_changes(D)] interface only reports the number 2537** of rows that changed due to SQL statement run against database 2538** connection D. Any changes by other database connections are ignored. 2539** To detect changes against a database file from other database 2540** connections use the [PRAGMA data_version] command or the 2541** [SQLITE_FCNTL_DATA_VERSION] [file control]. 2542** 2543** If a separate thread makes changes on the same database connection 2544** while [sqlite3_total_changes()] is running then the value 2545** returned is unpredictable and not meaningful. 2546** 2547** See also: 2548** <ul> 2549** <li> the [sqlite3_changes()] interface 2550** <li> the [count_changes pragma] 2551** <li> the [changes() SQL function] 2552** <li> the [data_version pragma] 2553** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control] 2554** </ul> 2555*/ 2556int sqlite3_total_changes(sqlite3*); 2557 2558/* 2559** CAPI3REF: Interrupt A Long-Running Query 2560** METHOD: sqlite3 2561** 2562** ^This function causes any pending database operation to abort and 2563** return at its earliest opportunity. This routine is typically 2564** called in response to a user action such as pressing "Cancel" 2565** or Ctrl-C where the user wants a long query operation to halt 2566** immediately. 2567** 2568** ^It is safe to call this routine from a thread different from the 2569** thread that is currently running the database operation. But it 2570** is not safe to call this routine with a [database connection] that 2571** is closed or might close before sqlite3_interrupt() returns. 2572** 2573** ^If an SQL operation is very nearly finished at the time when 2574** sqlite3_interrupt() is called, then it might not have an opportunity 2575** to be interrupted and might continue to completion. 2576** 2577** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2578** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2579** that is inside an explicit transaction, then the entire transaction 2580** will be rolled back automatically. 2581** 2582** ^The sqlite3_interrupt(D) call is in effect until all currently running 2583** SQL statements on [database connection] D complete. ^Any new SQL statements 2584** that are started after the sqlite3_interrupt() call and before the 2585** running statement count reaches zero are interrupted as if they had been 2586** running prior to the sqlite3_interrupt() call. ^New SQL statements 2587** that are started after the running statement count reaches zero are 2588** not effected by the sqlite3_interrupt(). 2589** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2590** SQL statements is a no-op and has no effect on SQL statements 2591** that are started after the sqlite3_interrupt() call returns. 2592*/ 2593void sqlite3_interrupt(sqlite3*); 2594 2595/* 2596** CAPI3REF: Determine If An SQL Statement Is Complete 2597** 2598** These routines are useful during command-line input to determine if the 2599** currently entered text seems to form a complete SQL statement or 2600** if additional input is needed before sending the text into 2601** SQLite for parsing. ^These routines return 1 if the input string 2602** appears to be a complete SQL statement. ^A statement is judged to be 2603** complete if it ends with a semicolon token and is not a prefix of a 2604** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2605** string literals or quoted identifier names or comments are not 2606** independent tokens (they are part of the token in which they are 2607** embedded) and thus do not count as a statement terminator. ^Whitespace 2608** and comments that follow the final semicolon are ignored. 2609** 2610** ^These routines return 0 if the statement is incomplete. ^If a 2611** memory allocation fails, then SQLITE_NOMEM is returned. 2612** 2613** ^These routines do not parse the SQL statements thus 2614** will not detect syntactically incorrect SQL. 2615** 2616** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2617** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2618** automatically by sqlite3_complete16(). If that initialization fails, 2619** then the return value from sqlite3_complete16() will be non-zero 2620** regardless of whether or not the input SQL is complete.)^ 2621** 2622** The input to [sqlite3_complete()] must be a zero-terminated 2623** UTF-8 string. 2624** 2625** The input to [sqlite3_complete16()] must be a zero-terminated 2626** UTF-16 string in native byte order. 2627*/ 2628int sqlite3_complete(const char *sql); 2629int sqlite3_complete16(const void *sql); 2630 2631/* 2632** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2633** KEYWORDS: {busy-handler callback} {busy handler} 2634** METHOD: sqlite3 2635** 2636** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2637** that might be invoked with argument P whenever 2638** an attempt is made to access a database table associated with 2639** [database connection] D when another thread 2640** or process has the table locked. 2641** The sqlite3_busy_handler() interface is used to implement 2642** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2643** 2644** ^If the busy callback is NULL, then [SQLITE_BUSY] 2645** is returned immediately upon encountering the lock. ^If the busy callback 2646** is not NULL, then the callback might be invoked with two arguments. 2647** 2648** ^The first argument to the busy handler is a copy of the void* pointer which 2649** is the third argument to sqlite3_busy_handler(). ^The second argument to 2650** the busy handler callback is the number of times that the busy handler has 2651** been invoked previously for the same locking event. ^If the 2652** busy callback returns 0, then no additional attempts are made to 2653** access the database and [SQLITE_BUSY] is returned 2654** to the application. 2655** ^If the callback returns non-zero, then another attempt 2656** is made to access the database and the cycle repeats. 2657** 2658** The presence of a busy handler does not guarantee that it will be invoked 2659** when there is lock contention. ^If SQLite determines that invoking the busy 2660** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2661** to the application instead of invoking the 2662** busy handler. 2663** Consider a scenario where one process is holding a read lock that 2664** it is trying to promote to a reserved lock and 2665** a second process is holding a reserved lock that it is trying 2666** to promote to an exclusive lock. The first process cannot proceed 2667** because it is blocked by the second and the second process cannot 2668** proceed because it is blocked by the first. If both processes 2669** invoke the busy handlers, neither will make any progress. Therefore, 2670** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2671** will induce the first process to release its read lock and allow 2672** the second process to proceed. 2673** 2674** ^The default busy callback is NULL. 2675** 2676** ^(There can only be a single busy handler defined for each 2677** [database connection]. Setting a new busy handler clears any 2678** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2679** or evaluating [PRAGMA busy_timeout=N] will change the 2680** busy handler and thus clear any previously set busy handler. 2681** 2682** The busy callback should not take any actions which modify the 2683** database connection that invoked the busy handler. In other words, 2684** the busy handler is not reentrant. Any such actions 2685** result in undefined behavior. 2686** 2687** A busy handler must not close the database connection 2688** or [prepared statement] that invoked the busy handler. 2689*/ 2690int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2691 2692/* 2693** CAPI3REF: Set A Busy Timeout 2694** METHOD: sqlite3 2695** 2696** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2697** for a specified amount of time when a table is locked. ^The handler 2698** will sleep multiple times until at least "ms" milliseconds of sleeping 2699** have accumulated. ^After at least "ms" milliseconds of sleeping, 2700** the handler returns 0 which causes [sqlite3_step()] to return 2701** [SQLITE_BUSY]. 2702** 2703** ^Calling this routine with an argument less than or equal to zero 2704** turns off all busy handlers. 2705** 2706** ^(There can only be a single busy handler for a particular 2707** [database connection] at any given moment. If another busy handler 2708** was defined (using [sqlite3_busy_handler()]) prior to calling 2709** this routine, that other busy handler is cleared.)^ 2710** 2711** See also: [PRAGMA busy_timeout] 2712*/ 2713int sqlite3_busy_timeout(sqlite3*, int ms); 2714 2715/* 2716** CAPI3REF: Convenience Routines For Running Queries 2717** METHOD: sqlite3 2718** 2719** This is a legacy interface that is preserved for backwards compatibility. 2720** Use of this interface is not recommended. 2721** 2722** Definition: A <b>result table</b> is memory data structure created by the 2723** [sqlite3_get_table()] interface. A result table records the 2724** complete query results from one or more queries. 2725** 2726** The table conceptually has a number of rows and columns. But 2727** these numbers are not part of the result table itself. These 2728** numbers are obtained separately. Let N be the number of rows 2729** and M be the number of columns. 2730** 2731** A result table is an array of pointers to zero-terminated UTF-8 strings. 2732** There are (N+1)*M elements in the array. The first M pointers point 2733** to zero-terminated strings that contain the names of the columns. 2734** The remaining entries all point to query results. NULL values result 2735** in NULL pointers. All other values are in their UTF-8 zero-terminated 2736** string representation as returned by [sqlite3_column_text()]. 2737** 2738** A result table might consist of one or more memory allocations. 2739** It is not safe to pass a result table directly to [sqlite3_free()]. 2740** A result table should be deallocated using [sqlite3_free_table()]. 2741** 2742** ^(As an example of the result table format, suppose a query result 2743** is as follows: 2744** 2745** <blockquote><pre> 2746** Name | Age 2747** ----------------------- 2748** Alice | 43 2749** Bob | 28 2750** Cindy | 21 2751** </pre></blockquote> 2752** 2753** There are two columns (M==2) and three rows (N==3). Thus the 2754** result table has 8 entries. Suppose the result table is stored 2755** in an array named azResult. Then azResult holds this content: 2756** 2757** <blockquote><pre> 2758** azResult[0] = "Name"; 2759** azResult[1] = "Age"; 2760** azResult[2] = "Alice"; 2761** azResult[3] = "43"; 2762** azResult[4] = "Bob"; 2763** azResult[5] = "28"; 2764** azResult[6] = "Cindy"; 2765** azResult[7] = "21"; 2766** </pre></blockquote>)^ 2767** 2768** ^The sqlite3_get_table() function evaluates one or more 2769** semicolon-separated SQL statements in the zero-terminated UTF-8 2770** string of its 2nd parameter and returns a result table to the 2771** pointer given in its 3rd parameter. 2772** 2773** After the application has finished with the result from sqlite3_get_table(), 2774** it must pass the result table pointer to sqlite3_free_table() in order to 2775** release the memory that was malloced. Because of the way the 2776** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2777** function must not try to call [sqlite3_free()] directly. Only 2778** [sqlite3_free_table()] is able to release the memory properly and safely. 2779** 2780** The sqlite3_get_table() interface is implemented as a wrapper around 2781** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2782** to any internal data structures of SQLite. It uses only the public 2783** interface defined here. As a consequence, errors that occur in the 2784** wrapper layer outside of the internal [sqlite3_exec()] call are not 2785** reflected in subsequent calls to [sqlite3_errcode()] or 2786** [sqlite3_errmsg()]. 2787*/ 2788int sqlite3_get_table( 2789 sqlite3 *db, /* An open database */ 2790 const char *zSql, /* SQL to be evaluated */ 2791 char ***pazResult, /* Results of the query */ 2792 int *pnRow, /* Number of result rows written here */ 2793 int *pnColumn, /* Number of result columns written here */ 2794 char **pzErrmsg /* Error msg written here */ 2795); 2796void sqlite3_free_table(char **result); 2797 2798/* 2799** CAPI3REF: Formatted String Printing Functions 2800** 2801** These routines are work-alikes of the "printf()" family of functions 2802** from the standard C library. 2803** These routines understand most of the common formatting options from 2804** the standard library printf() 2805** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2806** See the [built-in printf()] documentation for details. 2807** 2808** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2809** results into memory obtained from [sqlite3_malloc64()]. 2810** The strings returned by these two routines should be 2811** released by [sqlite3_free()]. ^Both routines return a 2812** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2813** memory to hold the resulting string. 2814** 2815** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2816** the standard C library. The result is written into the 2817** buffer supplied as the second parameter whose size is given by 2818** the first parameter. Note that the order of the 2819** first two parameters is reversed from snprintf().)^ This is an 2820** historical accident that cannot be fixed without breaking 2821** backwards compatibility. ^(Note also that sqlite3_snprintf() 2822** returns a pointer to its buffer instead of the number of 2823** characters actually written into the buffer.)^ We admit that 2824** the number of characters written would be a more useful return 2825** value but we cannot change the implementation of sqlite3_snprintf() 2826** now without breaking compatibility. 2827** 2828** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2829** guarantees that the buffer is always zero-terminated. ^The first 2830** parameter "n" is the total size of the buffer, including space for 2831** the zero terminator. So the longest string that can be completely 2832** written will be n-1 characters. 2833** 2834** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2835** 2836** See also: [built-in printf()], [printf() SQL function] 2837*/ 2838char *sqlite3_mprintf(const char*,...); 2839char *sqlite3_vmprintf(const char*, va_list); 2840char *sqlite3_snprintf(int,char*,const char*, ...); 2841char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2842 2843/* 2844** CAPI3REF: Memory Allocation Subsystem 2845** 2846** The SQLite core uses these three routines for all of its own 2847** internal memory allocation needs. "Core" in the previous sentence 2848** does not include operating-system specific [VFS] implementation. The 2849** Windows VFS uses native malloc() and free() for some operations. 2850** 2851** ^The sqlite3_malloc() routine returns a pointer to a block 2852** of memory at least N bytes in length, where N is the parameter. 2853** ^If sqlite3_malloc() is unable to obtain sufficient free 2854** memory, it returns a NULL pointer. ^If the parameter N to 2855** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2856** a NULL pointer. 2857** 2858** ^The sqlite3_malloc64(N) routine works just like 2859** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2860** of a signed 32-bit integer. 2861** 2862** ^Calling sqlite3_free() with a pointer previously returned 2863** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2864** that it might be reused. ^The sqlite3_free() routine is 2865** a no-op if is called with a NULL pointer. Passing a NULL pointer 2866** to sqlite3_free() is harmless. After being freed, memory 2867** should neither be read nor written. Even reading previously freed 2868** memory might result in a segmentation fault or other severe error. 2869** Memory corruption, a segmentation fault, or other severe error 2870** might result if sqlite3_free() is called with a non-NULL pointer that 2871** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2872** 2873** ^The sqlite3_realloc(X,N) interface attempts to resize a 2874** prior memory allocation X to be at least N bytes. 2875** ^If the X parameter to sqlite3_realloc(X,N) 2876** is a NULL pointer then its behavior is identical to calling 2877** sqlite3_malloc(N). 2878** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2879** negative then the behavior is exactly the same as calling 2880** sqlite3_free(X). 2881** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2882** of at least N bytes in size or NULL if insufficient memory is available. 2883** ^If M is the size of the prior allocation, then min(N,M) bytes 2884** of the prior allocation are copied into the beginning of buffer returned 2885** by sqlite3_realloc(X,N) and the prior allocation is freed. 2886** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2887** prior allocation is not freed. 2888** 2889** ^The sqlite3_realloc64(X,N) interfaces works the same as 2890** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2891** of a 32-bit signed integer. 2892** 2893** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2894** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2895** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2896** ^The value returned by sqlite3_msize(X) might be larger than the number 2897** of bytes requested when X was allocated. ^If X is a NULL pointer then 2898** sqlite3_msize(X) returns zero. If X points to something that is not 2899** the beginning of memory allocation, or if it points to a formerly 2900** valid memory allocation that has now been freed, then the behavior 2901** of sqlite3_msize(X) is undefined and possibly harmful. 2902** 2903** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2904** sqlite3_malloc64(), and sqlite3_realloc64() 2905** is always aligned to at least an 8 byte boundary, or to a 2906** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2907** option is used. 2908** 2909** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2910** must be either NULL or else pointers obtained from a prior 2911** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2912** not yet been released. 2913** 2914** The application must not read or write any part of 2915** a block of memory after it has been released using 2916** [sqlite3_free()] or [sqlite3_realloc()]. 2917*/ 2918void *sqlite3_malloc(int); 2919void *sqlite3_malloc64(sqlite3_uint64); 2920void *sqlite3_realloc(void*, int); 2921void *sqlite3_realloc64(void*, sqlite3_uint64); 2922void sqlite3_free(void*); 2923sqlite3_uint64 sqlite3_msize(void*); 2924 2925/* 2926** CAPI3REF: Memory Allocator Statistics 2927** 2928** SQLite provides these two interfaces for reporting on the status 2929** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2930** routines, which form the built-in memory allocation subsystem. 2931** 2932** ^The [sqlite3_memory_used()] routine returns the number of bytes 2933** of memory currently outstanding (malloced but not freed). 2934** ^The [sqlite3_memory_highwater()] routine returns the maximum 2935** value of [sqlite3_memory_used()] since the high-water mark 2936** was last reset. ^The values returned by [sqlite3_memory_used()] and 2937** [sqlite3_memory_highwater()] include any overhead 2938** added by SQLite in its implementation of [sqlite3_malloc()], 2939** but not overhead added by the any underlying system library 2940** routines that [sqlite3_malloc()] may call. 2941** 2942** ^The memory high-water mark is reset to the current value of 2943** [sqlite3_memory_used()] if and only if the parameter to 2944** [sqlite3_memory_highwater()] is true. ^The value returned 2945** by [sqlite3_memory_highwater(1)] is the high-water mark 2946** prior to the reset. 2947*/ 2948sqlite3_int64 sqlite3_memory_used(void); 2949sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2950 2951/* 2952** CAPI3REF: Pseudo-Random Number Generator 2953** 2954** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2955** select random [ROWID | ROWIDs] when inserting new records into a table that 2956** already uses the largest possible [ROWID]. The PRNG is also used for 2957** the built-in random() and randomblob() SQL functions. This interface allows 2958** applications to access the same PRNG for other purposes. 2959** 2960** ^A call to this routine stores N bytes of randomness into buffer P. 2961** ^The P parameter can be a NULL pointer. 2962** 2963** ^If this routine has not been previously called or if the previous 2964** call had N less than one or a NULL pointer for P, then the PRNG is 2965** seeded using randomness obtained from the xRandomness method of 2966** the default [sqlite3_vfs] object. 2967** ^If the previous call to this routine had an N of 1 or more and a 2968** non-NULL P then the pseudo-randomness is generated 2969** internally and without recourse to the [sqlite3_vfs] xRandomness 2970** method. 2971*/ 2972void sqlite3_randomness(int N, void *P); 2973 2974/* 2975** CAPI3REF: Compile-Time Authorization Callbacks 2976** METHOD: sqlite3 2977** KEYWORDS: {authorizer callback} 2978** 2979** ^This routine registers an authorizer callback with a particular 2980** [database connection], supplied in the first argument. 2981** ^The authorizer callback is invoked as SQL statements are being compiled 2982** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2983** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2984** and [sqlite3_prepare16_v3()]. ^At various 2985** points during the compilation process, as logic is being created 2986** to perform various actions, the authorizer callback is invoked to 2987** see if those actions are allowed. ^The authorizer callback should 2988** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2989** specific action but allow the SQL statement to continue to be 2990** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2991** rejected with an error. ^If the authorizer callback returns 2992** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2993** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2994** the authorizer will fail with an error message. 2995** 2996** When the callback returns [SQLITE_OK], that means the operation 2997** requested is ok. ^When the callback returns [SQLITE_DENY], the 2998** [sqlite3_prepare_v2()] or equivalent call that triggered the 2999** authorizer will fail with an error message explaining that 3000** access is denied. 3001** 3002** ^The first parameter to the authorizer callback is a copy of the third 3003** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 3004** to the callback is an integer [SQLITE_COPY | action code] that specifies 3005** the particular action to be authorized. ^The third through sixth parameters 3006** to the callback are either NULL pointers or zero-terminated strings 3007** that contain additional details about the action to be authorized. 3008** Applications must always be prepared to encounter a NULL pointer in any 3009** of the third through the sixth parameters of the authorization callback. 3010** 3011** ^If the action code is [SQLITE_READ] 3012** and the callback returns [SQLITE_IGNORE] then the 3013** [prepared statement] statement is constructed to substitute 3014** a NULL value in place of the table column that would have 3015** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 3016** return can be used to deny an untrusted user access to individual 3017** columns of a table. 3018** ^When a table is referenced by a [SELECT] but no column values are 3019** extracted from that table (for example in a query like 3020** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 3021** is invoked once for that table with a column name that is an empty string. 3022** ^If the action code is [SQLITE_DELETE] and the callback returns 3023** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 3024** [truncate optimization] is disabled and all rows are deleted individually. 3025** 3026** An authorizer is used when [sqlite3_prepare | preparing] 3027** SQL statements from an untrusted source, to ensure that the SQL statements 3028** do not try to access data they are not allowed to see, or that they do not 3029** try to execute malicious statements that damage the database. For 3030** example, an application may allow a user to enter arbitrary 3031** SQL queries for evaluation by a database. But the application does 3032** not want the user to be able to make arbitrary changes to the 3033** database. An authorizer could then be put in place while the 3034** user-entered SQL is being [sqlite3_prepare | prepared] that 3035** disallows everything except [SELECT] statements. 3036** 3037** Applications that need to process SQL from untrusted sources 3038** might also consider lowering resource limits using [sqlite3_limit()] 3039** and limiting database size using the [max_page_count] [PRAGMA] 3040** in addition to using an authorizer. 3041** 3042** ^(Only a single authorizer can be in place on a database connection 3043** at a time. Each call to sqlite3_set_authorizer overrides the 3044** previous call.)^ ^Disable the authorizer by installing a NULL callback. 3045** The authorizer is disabled by default. 3046** 3047** The authorizer callback must not do anything that will modify 3048** the database connection that invoked the authorizer callback. 3049** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3050** database connections for the meaning of "modify" in this paragraph. 3051** 3052** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 3053** statement might be re-prepared during [sqlite3_step()] due to a 3054** schema change. Hence, the application should ensure that the 3055** correct authorizer callback remains in place during the [sqlite3_step()]. 3056** 3057** ^Note that the authorizer callback is invoked only during 3058** [sqlite3_prepare()] or its variants. Authorization is not 3059** performed during statement evaluation in [sqlite3_step()], unless 3060** as stated in the previous paragraph, sqlite3_step() invokes 3061** sqlite3_prepare_v2() to reprepare a statement after a schema change. 3062*/ 3063int sqlite3_set_authorizer( 3064 sqlite3*, 3065 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 3066 void *pUserData 3067); 3068 3069/* 3070** CAPI3REF: Authorizer Return Codes 3071** 3072** The [sqlite3_set_authorizer | authorizer callback function] must 3073** return either [SQLITE_OK] or one of these two constants in order 3074** to signal SQLite whether or not the action is permitted. See the 3075** [sqlite3_set_authorizer | authorizer documentation] for additional 3076** information. 3077** 3078** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 3079** returned from the [sqlite3_vtab_on_conflict()] interface. 3080*/ 3081#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 3082#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 3083 3084/* 3085** CAPI3REF: Authorizer Action Codes 3086** 3087** The [sqlite3_set_authorizer()] interface registers a callback function 3088** that is invoked to authorize certain SQL statement actions. The 3089** second parameter to the callback is an integer code that specifies 3090** what action is being authorized. These are the integer action codes that 3091** the authorizer callback may be passed. 3092** 3093** These action code values signify what kind of operation is to be 3094** authorized. The 3rd and 4th parameters to the authorization 3095** callback function will be parameters or NULL depending on which of these 3096** codes is used as the second parameter. ^(The 5th parameter to the 3097** authorizer callback is the name of the database ("main", "temp", 3098** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 3099** is the name of the inner-most trigger or view that is responsible for 3100** the access attempt or NULL if this access attempt is directly from 3101** top-level SQL code. 3102*/ 3103/******************************************* 3rd ************ 4th ***********/ 3104#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 3105#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 3106#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 3107#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 3108#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 3109#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 3110#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 3111#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 3112#define SQLITE_DELETE 9 /* Table Name NULL */ 3113#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 3114#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 3115#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 3116#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 3117#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 3118#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 3119#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 3120#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 3121#define SQLITE_INSERT 18 /* Table Name NULL */ 3122#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 3123#define SQLITE_READ 20 /* Table Name Column Name */ 3124#define SQLITE_SELECT 21 /* NULL NULL */ 3125#define SQLITE_TRANSACTION 22 /* Operation NULL */ 3126#define SQLITE_UPDATE 23 /* Table Name Column Name */ 3127#define SQLITE_ATTACH 24 /* Filename NULL */ 3128#define SQLITE_DETACH 25 /* Database Name NULL */ 3129#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 3130#define SQLITE_REINDEX 27 /* Index Name NULL */ 3131#define SQLITE_ANALYZE 28 /* Table Name NULL */ 3132#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 3133#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 3134#define SQLITE_FUNCTION 31 /* NULL Function Name */ 3135#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 3136#define SQLITE_COPY 0 /* No longer used */ 3137#define SQLITE_RECURSIVE 33 /* NULL NULL */ 3138 3139/* 3140** CAPI3REF: Tracing And Profiling Functions 3141** METHOD: sqlite3 3142** 3143** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 3144** instead of the routines described here. 3145** 3146** These routines register callback functions that can be used for 3147** tracing and profiling the execution of SQL statements. 3148** 3149** ^The callback function registered by sqlite3_trace() is invoked at 3150** various times when an SQL statement is being run by [sqlite3_step()]. 3151** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 3152** SQL statement text as the statement first begins executing. 3153** ^(Additional sqlite3_trace() callbacks might occur 3154** as each triggered subprogram is entered. The callbacks for triggers 3155** contain a UTF-8 SQL comment that identifies the trigger.)^ 3156** 3157** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 3158** the length of [bound parameter] expansion in the output of sqlite3_trace(). 3159** 3160** ^The callback function registered by sqlite3_profile() is invoked 3161** as each SQL statement finishes. ^The profile callback contains 3162** the original statement text and an estimate of wall-clock time 3163** of how long that statement took to run. ^The profile callback 3164** time is in units of nanoseconds, however the current implementation 3165** is only capable of millisecond resolution so the six least significant 3166** digits in the time are meaningless. Future versions of SQLite 3167** might provide greater resolution on the profiler callback. Invoking 3168** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the 3169** profile callback. 3170*/ 3171SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 3172 void(*xTrace)(void*,const char*), void*); 3173SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 3174 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 3175 3176/* 3177** CAPI3REF: SQL Trace Event Codes 3178** KEYWORDS: SQLITE_TRACE 3179** 3180** These constants identify classes of events that can be monitored 3181** using the [sqlite3_trace_v2()] tracing logic. The M argument 3182** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 3183** the following constants. ^The first argument to the trace callback 3184** is one of the following constants. 3185** 3186** New tracing constants may be added in future releases. 3187** 3188** ^A trace callback has four arguments: xCallback(T,C,P,X). 3189** ^The T argument is one of the integer type codes above. 3190** ^The C argument is a copy of the context pointer passed in as the 3191** fourth argument to [sqlite3_trace_v2()]. 3192** The P and X arguments are pointers whose meanings depend on T. 3193** 3194** <dl> 3195** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 3196** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 3197** first begins running and possibly at other times during the 3198** execution of the prepared statement, such as at the start of each 3199** trigger subprogram. ^The P argument is a pointer to the 3200** [prepared statement]. ^The X argument is a pointer to a string which 3201** is the unexpanded SQL text of the prepared statement or an SQL comment 3202** that indicates the invocation of a trigger. ^The callback can compute 3203** the same text that would have been returned by the legacy [sqlite3_trace()] 3204** interface by using the X argument when X begins with "--" and invoking 3205** [sqlite3_expanded_sql(P)] otherwise. 3206** 3207** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 3208** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 3209** information as is provided by the [sqlite3_profile()] callback. 3210** ^The P argument is a pointer to the [prepared statement] and the 3211** X argument points to a 64-bit integer which is the estimated of 3212** the number of nanosecond that the prepared statement took to run. 3213** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 3214** 3215** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 3216** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 3217** statement generates a single row of result. 3218** ^The P argument is a pointer to the [prepared statement] and the 3219** X argument is unused. 3220** 3221** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 3222** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 3223** connection closes. 3224** ^The P argument is a pointer to the [database connection] object 3225** and the X argument is unused. 3226** </dl> 3227*/ 3228#define SQLITE_TRACE_STMT 0x01 3229#define SQLITE_TRACE_PROFILE 0x02 3230#define SQLITE_TRACE_ROW 0x04 3231#define SQLITE_TRACE_CLOSE 0x08 3232 3233/* 3234** CAPI3REF: SQL Trace Hook 3235** METHOD: sqlite3 3236** 3237** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3238** function X against [database connection] D, using property mask M 3239** and context pointer P. ^If the X callback is 3240** NULL or if the M mask is zero, then tracing is disabled. The 3241** M argument should be the bitwise OR-ed combination of 3242** zero or more [SQLITE_TRACE] constants. 3243** 3244** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3245** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3246** 3247** ^The X callback is invoked whenever any of the events identified by 3248** mask M occur. ^The integer return value from the callback is currently 3249** ignored, though this may change in future releases. Callback 3250** implementations should return zero to ensure future compatibility. 3251** 3252** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3253** ^The T argument is one of the [SQLITE_TRACE] 3254** constants to indicate why the callback was invoked. 3255** ^The C argument is a copy of the context pointer. 3256** The P and X arguments are pointers whose meanings depend on T. 3257** 3258** The sqlite3_trace_v2() interface is intended to replace the legacy 3259** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3260** are deprecated. 3261*/ 3262int sqlite3_trace_v2( 3263 sqlite3*, 3264 unsigned uMask, 3265 int(*xCallback)(unsigned,void*,void*,void*), 3266 void *pCtx 3267); 3268 3269/* 3270** CAPI3REF: Query Progress Callbacks 3271** METHOD: sqlite3 3272** 3273** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3274** function X to be invoked periodically during long running calls to 3275** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3276** database connection D. An example use for this 3277** interface is to keep a GUI updated during a large query. 3278** 3279** ^The parameter P is passed through as the only parameter to the 3280** callback function X. ^The parameter N is the approximate number of 3281** [virtual machine instructions] that are evaluated between successive 3282** invocations of the callback X. ^If N is less than one then the progress 3283** handler is disabled. 3284** 3285** ^Only a single progress handler may be defined at one time per 3286** [database connection]; setting a new progress handler cancels the 3287** old one. ^Setting parameter X to NULL disables the progress handler. 3288** ^The progress handler is also disabled by setting N to a value less 3289** than 1. 3290** 3291** ^If the progress callback returns non-zero, the operation is 3292** interrupted. This feature can be used to implement a 3293** "Cancel" button on a GUI progress dialog box. 3294** 3295** The progress handler callback must not do anything that will modify 3296** the database connection that invoked the progress handler. 3297** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3298** database connections for the meaning of "modify" in this paragraph. 3299** 3300*/ 3301void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3302 3303/* 3304** CAPI3REF: Opening A New Database Connection 3305** CONSTRUCTOR: sqlite3 3306** 3307** ^These routines open an SQLite database file as specified by the 3308** filename argument. ^The filename argument is interpreted as UTF-8 for 3309** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3310** order for sqlite3_open16(). ^(A [database connection] handle is usually 3311** returned in *ppDb, even if an error occurs. The only exception is that 3312** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3313** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3314** object.)^ ^(If the database is opened (and/or created) successfully, then 3315** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3316** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3317** an English language description of the error following a failure of any 3318** of the sqlite3_open() routines. 3319** 3320** ^The default encoding will be UTF-8 for databases created using 3321** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3322** created using sqlite3_open16() will be UTF-16 in the native byte order. 3323** 3324** Whether or not an error occurs when it is opened, resources 3325** associated with the [database connection] handle should be released by 3326** passing it to [sqlite3_close()] when it is no longer required. 3327** 3328** The sqlite3_open_v2() interface works like sqlite3_open() 3329** except that it accepts two additional parameters for additional control 3330** over the new database connection. ^(The flags parameter to 3331** sqlite3_open_v2() must include, at a minimum, one of the following 3332** three flag combinations:)^ 3333** 3334** <dl> 3335** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3336** <dd>The database is opened in read-only mode. If the database does not 3337** already exist, an error is returned.</dd>)^ 3338** 3339** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3340** <dd>The database is opened for reading and writing if possible, or reading 3341** only if the file is write protected by the operating system. In either 3342** case the database must already exist, otherwise an error is returned.</dd>)^ 3343** 3344** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3345** <dd>The database is opened for reading and writing, and is created if 3346** it does not already exist. This is the behavior that is always used for 3347** sqlite3_open() and sqlite3_open16().</dd>)^ 3348** </dl> 3349** 3350** In addition to the required flags, the following optional flags are 3351** also supported: 3352** 3353** <dl> 3354** ^(<dt>[SQLITE_OPEN_URI]</dt> 3355** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^ 3356** 3357** ^(<dt>[SQLITE_OPEN_MEMORY]</dt> 3358** <dd>The database will be opened as an in-memory database. The database 3359** is named by the "filename" argument for the purposes of cache-sharing, 3360** if shared cache mode is enabled, but the "filename" is otherwise ignored. 3361** </dd>)^ 3362** 3363** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt> 3364** <dd>The new database connection will use the "multi-thread" 3365** [threading mode].)^ This means that separate threads are allowed 3366** to use SQLite at the same time, as long as each thread is using 3367** a different [database connection]. 3368** 3369** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt> 3370** <dd>The new database connection will use the "serialized" 3371** [threading mode].)^ This means the multiple threads can safely 3372** attempt to use the same database connection at the same time. 3373** (Mutexes will block any actual concurrency, but in this mode 3374** there is no harm in trying.) 3375** 3376** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt> 3377** <dd>The database is opened [shared cache] enabled, overriding 3378** the default shared cache setting provided by 3379** [sqlite3_enable_shared_cache()].)^ 3380** 3381** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt> 3382** <dd>The database is opened [shared cache] disabled, overriding 3383** the default shared cache setting provided by 3384** [sqlite3_enable_shared_cache()].)^ 3385** 3386** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt> 3387** <dd>The database filename is not allowed to be a symbolic link</dd> 3388** </dl>)^ 3389** 3390** If the 3rd parameter to sqlite3_open_v2() is not one of the 3391** required combinations shown above optionally combined with other 3392** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3393** then the behavior is undefined. 3394** 3395** ^The fourth parameter to sqlite3_open_v2() is the name of the 3396** [sqlite3_vfs] object that defines the operating system interface that 3397** the new database connection should use. ^If the fourth parameter is 3398** a NULL pointer then the default [sqlite3_vfs] object is used. 3399** 3400** ^If the filename is ":memory:", then a private, temporary in-memory database 3401** is created for the connection. ^This in-memory database will vanish when 3402** the database connection is closed. Future versions of SQLite might 3403** make use of additional special filenames that begin with the ":" character. 3404** It is recommended that when a database filename actually does begin with 3405** a ":" character you should prefix the filename with a pathname such as 3406** "./" to avoid ambiguity. 3407** 3408** ^If the filename is an empty string, then a private, temporary 3409** on-disk database will be created. ^This private database will be 3410** automatically deleted as soon as the database connection is closed. 3411** 3412** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3413** 3414** ^If [URI filename] interpretation is enabled, and the filename argument 3415** begins with "file:", then the filename is interpreted as a URI. ^URI 3416** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3417** set in the third argument to sqlite3_open_v2(), or if it has 3418** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3419** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3420** URI filename interpretation is turned off 3421** by default, but future releases of SQLite might enable URI filename 3422** interpretation by default. See "[URI filenames]" for additional 3423** information. 3424** 3425** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3426** authority, then it must be either an empty string or the string 3427** "localhost". ^If the authority is not an empty string or "localhost", an 3428** error is returned to the caller. ^The fragment component of a URI, if 3429** present, is ignored. 3430** 3431** ^SQLite uses the path component of the URI as the name of the disk file 3432** which contains the database. ^If the path begins with a '/' character, 3433** then it is interpreted as an absolute path. ^If the path does not begin 3434** with a '/' (meaning that the authority section is omitted from the URI) 3435** then the path is interpreted as a relative path. 3436** ^(On windows, the first component of an absolute path 3437** is a drive specification (e.g. "C:").)^ 3438** 3439** [[core URI query parameters]] 3440** The query component of a URI may contain parameters that are interpreted 3441** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3442** SQLite and its built-in [VFSes] interpret the 3443** following query parameters: 3444** 3445** <ul> 3446** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3447** a VFS object that provides the operating system interface that should 3448** be used to access the database file on disk. ^If this option is set to 3449** an empty string the default VFS object is used. ^Specifying an unknown 3450** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3451** present, then the VFS specified by the option takes precedence over 3452** the value passed as the fourth parameter to sqlite3_open_v2(). 3453** 3454** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3455** "rwc", or "memory". Attempting to set it to any other value is 3456** an error)^. 3457** ^If "ro" is specified, then the database is opened for read-only 3458** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3459** third argument to sqlite3_open_v2(). ^If the mode option is set to 3460** "rw", then the database is opened for read-write (but not create) 3461** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3462** been set. ^Value "rwc" is equivalent to setting both 3463** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3464** set to "memory" then a pure [in-memory database] that never reads 3465** or writes from disk is used. ^It is an error to specify a value for 3466** the mode parameter that is less restrictive than that specified by 3467** the flags passed in the third parameter to sqlite3_open_v2(). 3468** 3469** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3470** "private". ^Setting it to "shared" is equivalent to setting the 3471** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3472** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3473** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3474** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3475** a URI filename, its value overrides any behavior requested by setting 3476** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3477** 3478** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3479** [powersafe overwrite] property does or does not apply to the 3480** storage media on which the database file resides. 3481** 3482** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3483** which if set disables file locking in rollback journal modes. This 3484** is useful for accessing a database on a filesystem that does not 3485** support locking. Caution: Database corruption might result if two 3486** or more processes write to the same database and any one of those 3487** processes uses nolock=1. 3488** 3489** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3490** parameter that indicates that the database file is stored on 3491** read-only media. ^When immutable is set, SQLite assumes that the 3492** database file cannot be changed, even by a process with higher 3493** privilege, and so the database is opened read-only and all locking 3494** and change detection is disabled. Caution: Setting the immutable 3495** property on a database file that does in fact change can result 3496** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3497** See also: [SQLITE_IOCAP_IMMUTABLE]. 3498** 3499** </ul> 3500** 3501** ^Specifying an unknown parameter in the query component of a URI is not an 3502** error. Future versions of SQLite might understand additional query 3503** parameters. See "[query parameters with special meaning to SQLite]" for 3504** additional information. 3505** 3506** [[URI filename examples]] <h3>URI filename examples</h3> 3507** 3508** <table border="1" align=center cellpadding=5> 3509** <tr><th> URI filenames <th> Results 3510** <tr><td> file:data.db <td> 3511** Open the file "data.db" in the current directory. 3512** <tr><td> file:/home/fred/data.db<br> 3513** file:///home/fred/data.db <br> 3514** file://localhost/home/fred/data.db <br> <td> 3515** Open the database file "/home/fred/data.db". 3516** <tr><td> file://darkstar/home/fred/data.db <td> 3517** An error. "darkstar" is not a recognized authority. 3518** <tr><td style="white-space:nowrap"> 3519** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3520** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3521** C:. Note that the %20 escaping in this example is not strictly 3522** necessary - space characters can be used literally 3523** in URI filenames. 3524** <tr><td> file:data.db?mode=ro&cache=private <td> 3525** Open file "data.db" in the current directory for read-only access. 3526** Regardless of whether or not shared-cache mode is enabled by 3527** default, use a private cache. 3528** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3529** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3530** that uses dot-files in place of posix advisory locking. 3531** <tr><td> file:data.db?mode=readonly <td> 3532** An error. "readonly" is not a valid option for the "mode" parameter. 3533** Use "ro" instead: "file:data.db?mode=ro". 3534** </table> 3535** 3536** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3537** query components of a URI. A hexadecimal escape sequence consists of a 3538** percent sign - "%" - followed by exactly two hexadecimal digits 3539** specifying an octet value. ^Before the path or query components of a 3540** URI filename are interpreted, they are encoded using UTF-8 and all 3541** hexadecimal escape sequences replaced by a single byte containing the 3542** corresponding octet. If this process generates an invalid UTF-8 encoding, 3543** the results are undefined. 3544** 3545** <b>Note to Windows users:</b> The encoding used for the filename argument 3546** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3547** codepage is currently defined. Filenames containing international 3548** characters must be converted to UTF-8 prior to passing them into 3549** sqlite3_open() or sqlite3_open_v2(). 3550** 3551** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3552** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3553** features that require the use of temporary files may fail. 3554** 3555** See also: [sqlite3_temp_directory] 3556*/ 3557int sqlite3_open( 3558 const char *filename, /* Database filename (UTF-8) */ 3559 sqlite3 **ppDb /* OUT: SQLite db handle */ 3560); 3561int sqlite3_open16( 3562 const void *filename, /* Database filename (UTF-16) */ 3563 sqlite3 **ppDb /* OUT: SQLite db handle */ 3564); 3565int sqlite3_open_v2( 3566 const char *filename, /* Database filename (UTF-8) */ 3567 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3568 int flags, /* Flags */ 3569 const char *zVfs /* Name of VFS module to use */ 3570); 3571 3572/* 3573** CAPI3REF: Obtain Values For URI Parameters 3574** 3575** These are utility routines, useful to [VFS|custom VFS implementations], 3576** that check if a database file was a URI that contained a specific query 3577** parameter, and if so obtains the value of that query parameter. 3578** 3579** The first parameter to these interfaces (hereafter referred to 3580** as F) must be one of: 3581** <ul> 3582** <li> A database filename pointer created by the SQLite core and 3583** passed into the xOpen() method of a VFS implemention, or 3584** <li> A filename obtained from [sqlite3_db_filename()], or 3585** <li> A new filename constructed using [sqlite3_create_filename()]. 3586** </ul> 3587** If the F parameter is not one of the above, then the behavior is 3588** undefined and probably undesirable. Older versions of SQLite were 3589** more tolerant of invalid F parameters than newer versions. 3590** 3591** If F is a suitable filename (as described in the previous paragraph) 3592** and if P is the name of the query parameter, then 3593** sqlite3_uri_parameter(F,P) returns the value of the P 3594** parameter if it exists or a NULL pointer if P does not appear as a 3595** query parameter on F. If P is a query parameter of F and it 3596** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3597** a pointer to an empty string. 3598** 3599** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3600** parameter and returns true (1) or false (0) according to the value 3601** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3602** value of query parameter P is one of "yes", "true", or "on" in any 3603** case or if the value begins with a non-zero number. The 3604** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3605** query parameter P is one of "no", "false", or "off" in any case or 3606** if the value begins with a numeric zero. If P is not a query 3607** parameter on F or if the value of P does not match any of the 3608** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3609** 3610** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3611** 64-bit signed integer and returns that integer, or D if P does not 3612** exist. If the value of P is something other than an integer, then 3613** zero is returned. 3614** 3615** The sqlite3_uri_key(F,N) returns a pointer to the name (not 3616** the value) of the N-th query parameter for filename F, or a NULL 3617** pointer if N is less than zero or greater than the number of query 3618** parameters minus 1. The N value is zero-based so N should be 0 to obtain 3619** the name of the first query parameter, 1 for the second parameter, and 3620** so forth. 3621** 3622** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3623** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3624** is not a database file pathname pointer that the SQLite core passed 3625** into the xOpen VFS method, then the behavior of this routine is undefined 3626** and probably undesirable. 3627** 3628** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F 3629** parameter can also be the name of a rollback journal file or WAL file 3630** in addition to the main database file. Prior to version 3.31.0, these 3631** routines would only work if F was the name of the main database file. 3632** When the F parameter is the name of the rollback journal or WAL file, 3633** it has access to all the same query parameters as were found on the 3634** main database file. 3635** 3636** See the [URI filename] documentation for additional information. 3637*/ 3638const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3639int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3640sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3641const char *sqlite3_uri_key(const char *zFilename, int N); 3642 3643/* 3644** CAPI3REF: Translate filenames 3645** 3646** These routines are available to [VFS|custom VFS implementations] for 3647** translating filenames between the main database file, the journal file, 3648** and the WAL file. 3649** 3650** If F is the name of an sqlite database file, journal file, or WAL file 3651** passed by the SQLite core into the VFS, then sqlite3_filename_database(F) 3652** returns the name of the corresponding database file. 3653** 3654** If F is the name of an sqlite database file, journal file, or WAL file 3655** passed by the SQLite core into the VFS, or if F is a database filename 3656** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F) 3657** returns the name of the corresponding rollback journal file. 3658** 3659** If F is the name of an sqlite database file, journal file, or WAL file 3660** that was passed by the SQLite core into the VFS, or if F is a database 3661** filename obtained from [sqlite3_db_filename()], then 3662** sqlite3_filename_wal(F) returns the name of the corresponding 3663** WAL file. 3664** 3665** In all of the above, if F is not the name of a database, journal or WAL 3666** filename passed into the VFS from the SQLite core and F is not the 3667** return value from [sqlite3_db_filename()], then the result is 3668** undefined and is likely a memory access violation. 3669*/ 3670const char *sqlite3_filename_database(const char*); 3671const char *sqlite3_filename_journal(const char*); 3672const char *sqlite3_filename_wal(const char*); 3673 3674/* 3675** CAPI3REF: Database File Corresponding To A Journal 3676** 3677** ^If X is the name of a rollback or WAL-mode journal file that is 3678** passed into the xOpen method of [sqlite3_vfs], then 3679** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file] 3680** object that represents the main database file. 3681** 3682** This routine is intended for use in custom [VFS] implementations 3683** only. It is not a general-purpose interface. 3684** The argument sqlite3_file_object(X) must be a filename pointer that 3685** has been passed into [sqlite3_vfs].xOpen method where the 3686** flags parameter to xOpen contains one of the bits 3687** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL]. Any other use 3688** of this routine results in undefined and probably undesirable 3689** behavior. 3690*/ 3691sqlite3_file *sqlite3_database_file_object(const char*); 3692 3693/* 3694** CAPI3REF: Create and Destroy VFS Filenames 3695** 3696** These interfces are provided for use by [VFS shim] implementations and 3697** are not useful outside of that context. 3698** 3699** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of 3700** database filename D with corresponding journal file J and WAL file W and 3701** with N URI parameters key/values pairs in the array P. The result from 3702** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that 3703** is safe to pass to routines like: 3704** <ul> 3705** <li> [sqlite3_uri_parameter()], 3706** <li> [sqlite3_uri_boolean()], 3707** <li> [sqlite3_uri_int64()], 3708** <li> [sqlite3_uri_key()], 3709** <li> [sqlite3_filename_database()], 3710** <li> [sqlite3_filename_journal()], or 3711** <li> [sqlite3_filename_wal()]. 3712** </ul> 3713** If a memory allocation error occurs, sqlite3_create_filename() might 3714** return a NULL pointer. The memory obtained from sqlite3_create_filename(X) 3715** must be released by a corresponding call to sqlite3_free_filename(Y). 3716** 3717** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array 3718** of 2*N pointers to strings. Each pair of pointers in this array corresponds 3719** to a key and value for a query parameter. The P parameter may be a NULL 3720** pointer if N is zero. None of the 2*N pointers in the P array may be 3721** NULL pointers and key pointers should not be empty strings. 3722** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may 3723** be NULL pointers, though they can be empty strings. 3724** 3725** The sqlite3_free_filename(Y) routine releases a memory allocation 3726** previously obtained from sqlite3_create_filename(). Invoking 3727** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op. 3728** 3729** If the Y parameter to sqlite3_free_filename(Y) is anything other 3730** than a NULL pointer or a pointer previously acquired from 3731** sqlite3_create_filename(), then bad things such as heap 3732** corruption or segfaults may occur. The value Y should not be 3733** used again after sqlite3_free_filename(Y) has been called. This means 3734** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y, 3735** then the corresponding [sqlite3_module.xClose() method should also be 3736** invoked prior to calling sqlite3_free_filename(Y). 3737*/ 3738char *sqlite3_create_filename( 3739 const char *zDatabase, 3740 const char *zJournal, 3741 const char *zWal, 3742 int nParam, 3743 const char **azParam 3744); 3745void sqlite3_free_filename(char*); 3746 3747/* 3748** CAPI3REF: Error Codes And Messages 3749** METHOD: sqlite3 3750** 3751** ^If the most recent sqlite3_* API call associated with 3752** [database connection] D failed, then the sqlite3_errcode(D) interface 3753** returns the numeric [result code] or [extended result code] for that 3754** API call. 3755** ^The sqlite3_extended_errcode() 3756** interface is the same except that it always returns the 3757** [extended result code] even when extended result codes are 3758** disabled. 3759** 3760** The values returned by sqlite3_errcode() and/or 3761** sqlite3_extended_errcode() might change with each API call. 3762** Except, there are some interfaces that are guaranteed to never 3763** change the value of the error code. The error-code preserving 3764** interfaces are: 3765** 3766** <ul> 3767** <li> sqlite3_errcode() 3768** <li> sqlite3_extended_errcode() 3769** <li> sqlite3_errmsg() 3770** <li> sqlite3_errmsg16() 3771** </ul> 3772** 3773** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3774** text that describes the error, as either UTF-8 or UTF-16 respectively. 3775** ^(Memory to hold the error message string is managed internally. 3776** The application does not need to worry about freeing the result. 3777** However, the error string might be overwritten or deallocated by 3778** subsequent calls to other SQLite interface functions.)^ 3779** 3780** ^The sqlite3_errstr() interface returns the English-language text 3781** that describes the [result code], as UTF-8. 3782** ^(Memory to hold the error message string is managed internally 3783** and must not be freed by the application)^. 3784** 3785** When the serialized [threading mode] is in use, it might be the 3786** case that a second error occurs on a separate thread in between 3787** the time of the first error and the call to these interfaces. 3788** When that happens, the second error will be reported since these 3789** interfaces always report the most recent result. To avoid 3790** this, each thread can obtain exclusive use of the [database connection] D 3791** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3792** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3793** all calls to the interfaces listed here are completed. 3794** 3795** If an interface fails with SQLITE_MISUSE, that means the interface 3796** was invoked incorrectly by the application. In that case, the 3797** error code and message may or may not be set. 3798*/ 3799int sqlite3_errcode(sqlite3 *db); 3800int sqlite3_extended_errcode(sqlite3 *db); 3801const char *sqlite3_errmsg(sqlite3*); 3802const void *sqlite3_errmsg16(sqlite3*); 3803const char *sqlite3_errstr(int); 3804 3805/* 3806** CAPI3REF: Prepared Statement Object 3807** KEYWORDS: {prepared statement} {prepared statements} 3808** 3809** An instance of this object represents a single SQL statement that 3810** has been compiled into binary form and is ready to be evaluated. 3811** 3812** Think of each SQL statement as a separate computer program. The 3813** original SQL text is source code. A prepared statement object 3814** is the compiled object code. All SQL must be converted into a 3815** prepared statement before it can be run. 3816** 3817** The life-cycle of a prepared statement object usually goes like this: 3818** 3819** <ol> 3820** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3821** <li> Bind values to [parameters] using the sqlite3_bind_*() 3822** interfaces. 3823** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3824** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3825** to step 2. Do this zero or more times. 3826** <li> Destroy the object using [sqlite3_finalize()]. 3827** </ol> 3828*/ 3829typedef struct sqlite3_stmt sqlite3_stmt; 3830 3831/* 3832** CAPI3REF: Run-time Limits 3833** METHOD: sqlite3 3834** 3835** ^(This interface allows the size of various constructs to be limited 3836** on a connection by connection basis. The first parameter is the 3837** [database connection] whose limit is to be set or queried. The 3838** second parameter is one of the [limit categories] that define a 3839** class of constructs to be size limited. The third parameter is the 3840** new limit for that construct.)^ 3841** 3842** ^If the new limit is a negative number, the limit is unchanged. 3843** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3844** [limits | hard upper bound] 3845** set at compile-time by a C preprocessor macro called 3846** [limits | SQLITE_MAX_<i>NAME</i>]. 3847** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3848** ^Attempts to increase a limit above its hard upper bound are 3849** silently truncated to the hard upper bound. 3850** 3851** ^Regardless of whether or not the limit was changed, the 3852** [sqlite3_limit()] interface returns the prior value of the limit. 3853** ^Hence, to find the current value of a limit without changing it, 3854** simply invoke this interface with the third parameter set to -1. 3855** 3856** Run-time limits are intended for use in applications that manage 3857** both their own internal database and also databases that are controlled 3858** by untrusted external sources. An example application might be a 3859** web browser that has its own databases for storing history and 3860** separate databases controlled by JavaScript applications downloaded 3861** off the Internet. The internal databases can be given the 3862** large, default limits. Databases managed by external sources can 3863** be given much smaller limits designed to prevent a denial of service 3864** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3865** interface to further control untrusted SQL. The size of the database 3866** created by an untrusted script can be contained using the 3867** [max_page_count] [PRAGMA]. 3868** 3869** New run-time limit categories may be added in future releases. 3870*/ 3871int sqlite3_limit(sqlite3*, int id, int newVal); 3872 3873/* 3874** CAPI3REF: Run-Time Limit Categories 3875** KEYWORDS: {limit category} {*limit categories} 3876** 3877** These constants define various performance limits 3878** that can be lowered at run-time using [sqlite3_limit()]. 3879** The synopsis of the meanings of the various limits is shown below. 3880** Additional information is available at [limits | Limits in SQLite]. 3881** 3882** <dl> 3883** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3884** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3885** 3886** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3887** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3888** 3889** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3890** <dd>The maximum number of columns in a table definition or in the 3891** result set of a [SELECT] or the maximum number of columns in an index 3892** or in an ORDER BY or GROUP BY clause.</dd>)^ 3893** 3894** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3895** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3896** 3897** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3898** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3899** 3900** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3901** <dd>The maximum number of instructions in a virtual machine program 3902** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3903** the equivalent tries to allocate space for more than this many opcodes 3904** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3905** 3906** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3907** <dd>The maximum number of arguments on a function.</dd>)^ 3908** 3909** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3910** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3911** 3912** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3913** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3914** <dd>The maximum length of the pattern argument to the [LIKE] or 3915** [GLOB] operators.</dd>)^ 3916** 3917** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3918** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3919** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3920** 3921** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3922** <dd>The maximum depth of recursion for triggers.</dd>)^ 3923** 3924** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3925** <dd>The maximum number of auxiliary worker threads that a single 3926** [prepared statement] may start.</dd>)^ 3927** </dl> 3928*/ 3929#define SQLITE_LIMIT_LENGTH 0 3930#define SQLITE_LIMIT_SQL_LENGTH 1 3931#define SQLITE_LIMIT_COLUMN 2 3932#define SQLITE_LIMIT_EXPR_DEPTH 3 3933#define SQLITE_LIMIT_COMPOUND_SELECT 4 3934#define SQLITE_LIMIT_VDBE_OP 5 3935#define SQLITE_LIMIT_FUNCTION_ARG 6 3936#define SQLITE_LIMIT_ATTACHED 7 3937#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3938#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3939#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3940#define SQLITE_LIMIT_WORKER_THREADS 11 3941 3942/* 3943** CAPI3REF: Prepare Flags 3944** 3945** These constants define various flags that can be passed into 3946** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3947** [sqlite3_prepare16_v3()] interfaces. 3948** 3949** New flags may be added in future releases of SQLite. 3950** 3951** <dl> 3952** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3953** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3954** that the prepared statement will be retained for a long time and 3955** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3956** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3957** be used just once or at most a few times and then destroyed using 3958** [sqlite3_finalize()] relatively soon. The current implementation acts 3959** on this hint by avoiding the use of [lookaside memory] so as not to 3960** deplete the limited store of lookaside memory. Future versions of 3961** SQLite may act on this hint differently. 3962** 3963** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt> 3964** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used 3965** to be required for any prepared statement that wanted to use the 3966** [sqlite3_normalized_sql()] interface. However, the 3967** [sqlite3_normalized_sql()] interface is now available to all 3968** prepared statements, regardless of whether or not they use this 3969** flag. 3970** 3971** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt> 3972** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler 3973** to return an error (error code SQLITE_ERROR) if the statement uses 3974** any virtual tables. 3975** </dl> 3976*/ 3977#define SQLITE_PREPARE_PERSISTENT 0x01 3978#define SQLITE_PREPARE_NORMALIZE 0x02 3979#define SQLITE_PREPARE_NO_VTAB 0x04 3980 3981/* 3982** CAPI3REF: Compiling An SQL Statement 3983** KEYWORDS: {SQL statement compiler} 3984** METHOD: sqlite3 3985** CONSTRUCTOR: sqlite3_stmt 3986** 3987** To execute an SQL statement, it must first be compiled into a byte-code 3988** program using one of these routines. Or, in other words, these routines 3989** are constructors for the [prepared statement] object. 3990** 3991** The preferred routine to use is [sqlite3_prepare_v2()]. The 3992** [sqlite3_prepare()] interface is legacy and should be avoided. 3993** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3994** for special purposes. 3995** 3996** The use of the UTF-8 interfaces is preferred, as SQLite currently 3997** does all parsing using UTF-8. The UTF-16 interfaces are provided 3998** as a convenience. The UTF-16 interfaces work by converting the 3999** input text into UTF-8, then invoking the corresponding UTF-8 interface. 4000** 4001** The first argument, "db", is a [database connection] obtained from a 4002** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 4003** [sqlite3_open16()]. The database connection must not have been closed. 4004** 4005** The second argument, "zSql", is the statement to be compiled, encoded 4006** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 4007** and sqlite3_prepare_v3() 4008** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 4009** and sqlite3_prepare16_v3() use UTF-16. 4010** 4011** ^If the nByte argument is negative, then zSql is read up to the 4012** first zero terminator. ^If nByte is positive, then it is the 4013** number of bytes read from zSql. ^If nByte is zero, then no prepared 4014** statement is generated. 4015** If the caller knows that the supplied string is nul-terminated, then 4016** there is a small performance advantage to passing an nByte parameter that 4017** is the number of bytes in the input string <i>including</i> 4018** the nul-terminator. 4019** 4020** ^If pzTail is not NULL then *pzTail is made to point to the first byte 4021** past the end of the first SQL statement in zSql. These routines only 4022** compile the first statement in zSql, so *pzTail is left pointing to 4023** what remains uncompiled. 4024** 4025** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 4026** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 4027** to NULL. ^If the input text contains no SQL (if the input is an empty 4028** string or a comment) then *ppStmt is set to NULL. 4029** The calling procedure is responsible for deleting the compiled 4030** SQL statement using [sqlite3_finalize()] after it has finished with it. 4031** ppStmt may not be NULL. 4032** 4033** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 4034** otherwise an [error code] is returned. 4035** 4036** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 4037** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 4038** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 4039** are retained for backwards compatibility, but their use is discouraged. 4040** ^In the "vX" interfaces, the prepared statement 4041** that is returned (the [sqlite3_stmt] object) contains a copy of the 4042** original SQL text. This causes the [sqlite3_step()] interface to 4043** behave differently in three ways: 4044** 4045** <ol> 4046** <li> 4047** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 4048** always used to do, [sqlite3_step()] will automatically recompile the SQL 4049** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 4050** retries will occur before sqlite3_step() gives up and returns an error. 4051** </li> 4052** 4053** <li> 4054** ^When an error occurs, [sqlite3_step()] will return one of the detailed 4055** [error codes] or [extended error codes]. ^The legacy behavior was that 4056** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 4057** and the application would have to make a second call to [sqlite3_reset()] 4058** in order to find the underlying cause of the problem. With the "v2" prepare 4059** interfaces, the underlying reason for the error is returned immediately. 4060** </li> 4061** 4062** <li> 4063** ^If the specific value bound to a [parameter | host parameter] in the 4064** WHERE clause might influence the choice of query plan for a statement, 4065** then the statement will be automatically recompiled, as if there had been 4066** a schema change, on the first [sqlite3_step()] call following any change 4067** to the [sqlite3_bind_text | bindings] of that [parameter]. 4068** ^The specific value of a WHERE-clause [parameter] might influence the 4069** choice of query plan if the parameter is the left-hand side of a [LIKE] 4070** or [GLOB] operator or if the parameter is compared to an indexed column 4071** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled. 4072** </li> 4073** </ol> 4074** 4075** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 4076** the extra prepFlags parameter, which is a bit array consisting of zero or 4077** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 4078** sqlite3_prepare_v2() interface works exactly the same as 4079** sqlite3_prepare_v3() with a zero prepFlags parameter. 4080*/ 4081int sqlite3_prepare( 4082 sqlite3 *db, /* Database handle */ 4083 const char *zSql, /* SQL statement, UTF-8 encoded */ 4084 int nByte, /* Maximum length of zSql in bytes. */ 4085 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4086 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4087); 4088int sqlite3_prepare_v2( 4089 sqlite3 *db, /* Database handle */ 4090 const char *zSql, /* SQL statement, UTF-8 encoded */ 4091 int nByte, /* Maximum length of zSql in bytes. */ 4092 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4093 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4094); 4095int sqlite3_prepare_v3( 4096 sqlite3 *db, /* Database handle */ 4097 const char *zSql, /* SQL statement, UTF-8 encoded */ 4098 int nByte, /* Maximum length of zSql in bytes. */ 4099 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4100 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4101 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4102); 4103int sqlite3_prepare16( 4104 sqlite3 *db, /* Database handle */ 4105 const void *zSql, /* SQL statement, UTF-16 encoded */ 4106 int nByte, /* Maximum length of zSql in bytes. */ 4107 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4108 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4109); 4110int sqlite3_prepare16_v2( 4111 sqlite3 *db, /* Database handle */ 4112 const void *zSql, /* SQL statement, UTF-16 encoded */ 4113 int nByte, /* Maximum length of zSql in bytes. */ 4114 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4115 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4116); 4117int sqlite3_prepare16_v3( 4118 sqlite3 *db, /* Database handle */ 4119 const void *zSql, /* SQL statement, UTF-16 encoded */ 4120 int nByte, /* Maximum length of zSql in bytes. */ 4121 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4122 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4123 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4124); 4125 4126/* 4127** CAPI3REF: Retrieving Statement SQL 4128** METHOD: sqlite3_stmt 4129** 4130** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 4131** SQL text used to create [prepared statement] P if P was 4132** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 4133** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4134** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 4135** string containing the SQL text of prepared statement P with 4136** [bound parameters] expanded. 4137** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8 4138** string containing the normalized SQL text of prepared statement P. The 4139** semantics used to normalize a SQL statement are unspecified and subject 4140** to change. At a minimum, literal values will be replaced with suitable 4141** placeholders. 4142** 4143** ^(For example, if a prepared statement is created using the SQL 4144** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 4145** and parameter :xyz is unbound, then sqlite3_sql() will return 4146** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 4147** will return "SELECT 2345,NULL".)^ 4148** 4149** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 4150** is available to hold the result, or if the result would exceed the 4151** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 4152** 4153** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 4154** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 4155** option causes sqlite3_expanded_sql() to always return NULL. 4156** 4157** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P) 4158** are managed by SQLite and are automatically freed when the prepared 4159** statement is finalized. 4160** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 4161** is obtained from [sqlite3_malloc()] and must be free by the application 4162** by passing it to [sqlite3_free()]. 4163*/ 4164const char *sqlite3_sql(sqlite3_stmt *pStmt); 4165char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 4166const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt); 4167 4168/* 4169** CAPI3REF: Determine If An SQL Statement Writes The Database 4170** METHOD: sqlite3_stmt 4171** 4172** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 4173** and only if the [prepared statement] X makes no direct changes to 4174** the content of the database file. 4175** 4176** Note that [application-defined SQL functions] or 4177** [virtual tables] might change the database indirectly as a side effect. 4178** ^(For example, if an application defines a function "eval()" that 4179** calls [sqlite3_exec()], then the following SQL statement would 4180** change the database file through side-effects: 4181** 4182** <blockquote><pre> 4183** SELECT eval('DELETE FROM t1') FROM t2; 4184** </pre></blockquote> 4185** 4186** But because the [SELECT] statement does not change the database file 4187** directly, sqlite3_stmt_readonly() would still return true.)^ 4188** 4189** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 4190** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 4191** since the statements themselves do not actually modify the database but 4192** rather they control the timing of when other statements modify the 4193** database. ^The [ATTACH] and [DETACH] statements also cause 4194** sqlite3_stmt_readonly() to return true since, while those statements 4195** change the configuration of a database connection, they do not make 4196** changes to the content of the database files on disk. 4197** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 4198** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 4199** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 4200** sqlite3_stmt_readonly() returns false for those commands. 4201** 4202** ^This routine returns false if there is any possibility that the 4203** statement might change the database file. ^A false return does 4204** not guarantee that the statement will change the database file. 4205** ^For example, an UPDATE statement might have a WHERE clause that 4206** makes it a no-op, but the sqlite3_stmt_readonly() result would still 4207** be false. ^Similarly, a CREATE TABLE IF NOT EXISTS statement is a 4208** read-only no-op if the table already exists, but 4209** sqlite3_stmt_readonly() still returns false for such a statement. 4210*/ 4211int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 4212 4213/* 4214** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement 4215** METHOD: sqlite3_stmt 4216** 4217** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the 4218** prepared statement S is an EXPLAIN statement, or 2 if the 4219** statement S is an EXPLAIN QUERY PLAN. 4220** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is 4221** an ordinary statement or a NULL pointer. 4222*/ 4223int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt); 4224 4225/* 4226** CAPI3REF: Determine If A Prepared Statement Has Been Reset 4227** METHOD: sqlite3_stmt 4228** 4229** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 4230** [prepared statement] S has been stepped at least once using 4231** [sqlite3_step(S)] but has neither run to completion (returned 4232** [SQLITE_DONE] from [sqlite3_step(S)]) nor 4233** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 4234** interface returns false if S is a NULL pointer. If S is not a 4235** NULL pointer and is not a pointer to a valid [prepared statement] 4236** object, then the behavior is undefined and probably undesirable. 4237** 4238** This interface can be used in combination [sqlite3_next_stmt()] 4239** to locate all prepared statements associated with a database 4240** connection that are in need of being reset. This can be used, 4241** for example, in diagnostic routines to search for prepared 4242** statements that are holding a transaction open. 4243*/ 4244int sqlite3_stmt_busy(sqlite3_stmt*); 4245 4246/* 4247** CAPI3REF: Dynamically Typed Value Object 4248** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 4249** 4250** SQLite uses the sqlite3_value object to represent all values 4251** that can be stored in a database table. SQLite uses dynamic typing 4252** for the values it stores. ^Values stored in sqlite3_value objects 4253** can be integers, floating point values, strings, BLOBs, or NULL. 4254** 4255** An sqlite3_value object may be either "protected" or "unprotected". 4256** Some interfaces require a protected sqlite3_value. Other interfaces 4257** will accept either a protected or an unprotected sqlite3_value. 4258** Every interface that accepts sqlite3_value arguments specifies 4259** whether or not it requires a protected sqlite3_value. The 4260** [sqlite3_value_dup()] interface can be used to construct a new 4261** protected sqlite3_value from an unprotected sqlite3_value. 4262** 4263** The terms "protected" and "unprotected" refer to whether or not 4264** a mutex is held. An internal mutex is held for a protected 4265** sqlite3_value object but no mutex is held for an unprotected 4266** sqlite3_value object. If SQLite is compiled to be single-threaded 4267** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 4268** or if SQLite is run in one of reduced mutex modes 4269** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 4270** then there is no distinction between protected and unprotected 4271** sqlite3_value objects and they can be used interchangeably. However, 4272** for maximum code portability it is recommended that applications 4273** still make the distinction between protected and unprotected 4274** sqlite3_value objects even when not strictly required. 4275** 4276** ^The sqlite3_value objects that are passed as parameters into the 4277** implementation of [application-defined SQL functions] are protected. 4278** ^The sqlite3_value object returned by 4279** [sqlite3_column_value()] is unprotected. 4280** Unprotected sqlite3_value objects may only be used as arguments 4281** to [sqlite3_result_value()], [sqlite3_bind_value()], and 4282** [sqlite3_value_dup()]. 4283** The [sqlite3_value_blob | sqlite3_value_type()] family of 4284** interfaces require protected sqlite3_value objects. 4285*/ 4286typedef struct sqlite3_value sqlite3_value; 4287 4288/* 4289** CAPI3REF: SQL Function Context Object 4290** 4291** The context in which an SQL function executes is stored in an 4292** sqlite3_context object. ^A pointer to an sqlite3_context object 4293** is always first parameter to [application-defined SQL functions]. 4294** The application-defined SQL function implementation will pass this 4295** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 4296** [sqlite3_aggregate_context()], [sqlite3_user_data()], 4297** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 4298** and/or [sqlite3_set_auxdata()]. 4299*/ 4300typedef struct sqlite3_context sqlite3_context; 4301 4302/* 4303** CAPI3REF: Binding Values To Prepared Statements 4304** KEYWORDS: {host parameter} {host parameters} {host parameter name} 4305** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 4306** METHOD: sqlite3_stmt 4307** 4308** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 4309** literals may be replaced by a [parameter] that matches one of following 4310** templates: 4311** 4312** <ul> 4313** <li> ? 4314** <li> ?NNN 4315** <li> :VVV 4316** <li> @VVV 4317** <li> $VVV 4318** </ul> 4319** 4320** In the templates above, NNN represents an integer literal, 4321** and VVV represents an alphanumeric identifier.)^ ^The values of these 4322** parameters (also called "host parameter names" or "SQL parameters") 4323** can be set using the sqlite3_bind_*() routines defined here. 4324** 4325** ^The first argument to the sqlite3_bind_*() routines is always 4326** a pointer to the [sqlite3_stmt] object returned from 4327** [sqlite3_prepare_v2()] or its variants. 4328** 4329** ^The second argument is the index of the SQL parameter to be set. 4330** ^The leftmost SQL parameter has an index of 1. ^When the same named 4331** SQL parameter is used more than once, second and subsequent 4332** occurrences have the same index as the first occurrence. 4333** ^The index for named parameters can be looked up using the 4334** [sqlite3_bind_parameter_index()] API if desired. ^The index 4335** for "?NNN" parameters is the value of NNN. 4336** ^The NNN value must be between 1 and the [sqlite3_limit()] 4337** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766). 4338** 4339** ^The third argument is the value to bind to the parameter. 4340** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4341** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 4342** is ignored and the end result is the same as sqlite3_bind_null(). 4343** ^If the third parameter to sqlite3_bind_text() is not NULL, then 4344** it should be a pointer to well-formed UTF8 text. 4345** ^If the third parameter to sqlite3_bind_text16() is not NULL, then 4346** it should be a pointer to well-formed UTF16 text. 4347** ^If the third parameter to sqlite3_bind_text64() is not NULL, then 4348** it should be a pointer to a well-formed unicode string that is 4349** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16 4350** otherwise. 4351** 4352** [[byte-order determination rules]] ^The byte-order of 4353** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF) 4354** found in first character, which is removed, or in the absence of a BOM 4355** the byte order is the native byte order of the host 4356** machine for sqlite3_bind_text16() or the byte order specified in 4357** the 6th parameter for sqlite3_bind_text64().)^ 4358** ^If UTF16 input text contains invalid unicode 4359** characters, then SQLite might change those invalid characters 4360** into the unicode replacement character: U+FFFD. 4361** 4362** ^(In those routines that have a fourth argument, its value is the 4363** number of bytes in the parameter. To be clear: the value is the 4364** number of <u>bytes</u> in the value, not the number of characters.)^ 4365** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4366** is negative, then the length of the string is 4367** the number of bytes up to the first zero terminator. 4368** If the fourth parameter to sqlite3_bind_blob() is negative, then 4369** the behavior is undefined. 4370** If a non-negative fourth parameter is provided to sqlite3_bind_text() 4371** or sqlite3_bind_text16() or sqlite3_bind_text64() then 4372** that parameter must be the byte offset 4373** where the NUL terminator would occur assuming the string were NUL 4374** terminated. If any NUL characters occurs at byte offsets less than 4375** the value of the fourth parameter then the resulting string value will 4376** contain embedded NULs. The result of expressions involving strings 4377** with embedded NULs is undefined. 4378** 4379** ^The fifth argument to the BLOB and string binding interfaces controls 4380** or indicates the lifetime of the object referenced by the third parameter. 4381** ^These three options exist: 4382** ^(1) A destructor to dispose of the BLOB or string after SQLite has finished 4383** with it may be passed. ^It is called to dispose of the BLOB or string even 4384** if the call to the bind API fails, except the destructor is not called if 4385** the third parameter is a NULL pointer or the fourth parameter is negative. 4386** ^(2) The special constant, [SQLITE_STATIC], may be passsed to indicate that 4387** the application remains responsible for disposing of the object. ^In this 4388** case, the object and the provided pointer to it must remain valid until 4389** either the prepared statement is finalized or the same SQL parameter is 4390** bound to something else, whichever occurs sooner. 4391** ^(3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the 4392** object is to be copied prior to the return from sqlite3_bind_*(). ^The 4393** object and pointer to it must remain valid until then. ^SQLite will then 4394** manage the lifetime of its private copy. 4395** 4396** ^The sixth argument to sqlite3_bind_text64() must be one of 4397** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 4398** to specify the encoding of the text in the third parameter. If 4399** the sixth argument to sqlite3_bind_text64() is not one of the 4400** allowed values shown above, or if the text encoding is different 4401** from the encoding specified by the sixth parameter, then the behavior 4402** is undefined. 4403** 4404** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 4405** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 4406** (just an integer to hold its size) while it is being processed. 4407** Zeroblobs are intended to serve as placeholders for BLOBs whose 4408** content is later written using 4409** [sqlite3_blob_open | incremental BLOB I/O] routines. 4410** ^A negative value for the zeroblob results in a zero-length BLOB. 4411** 4412** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 4413** [prepared statement] S to have an SQL value of NULL, but to also be 4414** associated with the pointer P of type T. ^D is either a NULL pointer or 4415** a pointer to a destructor function for P. ^SQLite will invoke the 4416** destructor D with a single argument of P when it is finished using 4417** P. The T parameter should be a static string, preferably a string 4418** literal. The sqlite3_bind_pointer() routine is part of the 4419** [pointer passing interface] added for SQLite 3.20.0. 4420** 4421** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 4422** for the [prepared statement] or with a prepared statement for which 4423** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 4424** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 4425** routine is passed a [prepared statement] that has been finalized, the 4426** result is undefined and probably harmful. 4427** 4428** ^Bindings are not cleared by the [sqlite3_reset()] routine. 4429** ^Unbound parameters are interpreted as NULL. 4430** 4431** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 4432** [error code] if anything goes wrong. 4433** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 4434** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 4435** [SQLITE_MAX_LENGTH]. 4436** ^[SQLITE_RANGE] is returned if the parameter 4437** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 4438** 4439** See also: [sqlite3_bind_parameter_count()], 4440** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 4441*/ 4442int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 4443int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 4444 void(*)(void*)); 4445int sqlite3_bind_double(sqlite3_stmt*, int, double); 4446int sqlite3_bind_int(sqlite3_stmt*, int, int); 4447int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 4448int sqlite3_bind_null(sqlite3_stmt*, int); 4449int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 4450int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 4451int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 4452 void(*)(void*), unsigned char encoding); 4453int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 4454int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 4455int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 4456int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 4457 4458/* 4459** CAPI3REF: Number Of SQL Parameters 4460** METHOD: sqlite3_stmt 4461** 4462** ^This routine can be used to find the number of [SQL parameters] 4463** in a [prepared statement]. SQL parameters are tokens of the 4464** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4465** placeholders for values that are [sqlite3_bind_blob | bound] 4466** to the parameters at a later time. 4467** 4468** ^(This routine actually returns the index of the largest (rightmost) 4469** parameter. For all forms except ?NNN, this will correspond to the 4470** number of unique parameters. If parameters of the ?NNN form are used, 4471** there may be gaps in the list.)^ 4472** 4473** See also: [sqlite3_bind_blob|sqlite3_bind()], 4474** [sqlite3_bind_parameter_name()], and 4475** [sqlite3_bind_parameter_index()]. 4476*/ 4477int sqlite3_bind_parameter_count(sqlite3_stmt*); 4478 4479/* 4480** CAPI3REF: Name Of A Host Parameter 4481** METHOD: sqlite3_stmt 4482** 4483** ^The sqlite3_bind_parameter_name(P,N) interface returns 4484** the name of the N-th [SQL parameter] in the [prepared statement] P. 4485** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4486** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4487** respectively. 4488** In other words, the initial ":" or "$" or "@" or "?" 4489** is included as part of the name.)^ 4490** ^Parameters of the form "?" without a following integer have no name 4491** and are referred to as "nameless" or "anonymous parameters". 4492** 4493** ^The first host parameter has an index of 1, not 0. 4494** 4495** ^If the value N is out of range or if the N-th parameter is 4496** nameless, then NULL is returned. ^The returned string is 4497** always in UTF-8 encoding even if the named parameter was 4498** originally specified as UTF-16 in [sqlite3_prepare16()], 4499** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4500** 4501** See also: [sqlite3_bind_blob|sqlite3_bind()], 4502** [sqlite3_bind_parameter_count()], and 4503** [sqlite3_bind_parameter_index()]. 4504*/ 4505const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4506 4507/* 4508** CAPI3REF: Index Of A Parameter With A Given Name 4509** METHOD: sqlite3_stmt 4510** 4511** ^Return the index of an SQL parameter given its name. ^The 4512** index value returned is suitable for use as the second 4513** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4514** is returned if no matching parameter is found. ^The parameter 4515** name must be given in UTF-8 even if the original statement 4516** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4517** [sqlite3_prepare16_v3()]. 4518** 4519** See also: [sqlite3_bind_blob|sqlite3_bind()], 4520** [sqlite3_bind_parameter_count()], and 4521** [sqlite3_bind_parameter_name()]. 4522*/ 4523int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4524 4525/* 4526** CAPI3REF: Reset All Bindings On A Prepared Statement 4527** METHOD: sqlite3_stmt 4528** 4529** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4530** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4531** ^Use this routine to reset all host parameters to NULL. 4532*/ 4533int sqlite3_clear_bindings(sqlite3_stmt*); 4534 4535/* 4536** CAPI3REF: Number Of Columns In A Result Set 4537** METHOD: sqlite3_stmt 4538** 4539** ^Return the number of columns in the result set returned by the 4540** [prepared statement]. ^If this routine returns 0, that means the 4541** [prepared statement] returns no data (for example an [UPDATE]). 4542** ^However, just because this routine returns a positive number does not 4543** mean that one or more rows of data will be returned. ^A SELECT statement 4544** will always have a positive sqlite3_column_count() but depending on the 4545** WHERE clause constraints and the table content, it might return no rows. 4546** 4547** See also: [sqlite3_data_count()] 4548*/ 4549int sqlite3_column_count(sqlite3_stmt *pStmt); 4550 4551/* 4552** CAPI3REF: Column Names In A Result Set 4553** METHOD: sqlite3_stmt 4554** 4555** ^These routines return the name assigned to a particular column 4556** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4557** interface returns a pointer to a zero-terminated UTF-8 string 4558** and sqlite3_column_name16() returns a pointer to a zero-terminated 4559** UTF-16 string. ^The first parameter is the [prepared statement] 4560** that implements the [SELECT] statement. ^The second parameter is the 4561** column number. ^The leftmost column is number 0. 4562** 4563** ^The returned string pointer is valid until either the [prepared statement] 4564** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4565** reprepared by the first call to [sqlite3_step()] for a particular run 4566** or until the next call to 4567** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4568** 4569** ^If sqlite3_malloc() fails during the processing of either routine 4570** (for example during a conversion from UTF-8 to UTF-16) then a 4571** NULL pointer is returned. 4572** 4573** ^The name of a result column is the value of the "AS" clause for 4574** that column, if there is an AS clause. If there is no AS clause 4575** then the name of the column is unspecified and may change from 4576** one release of SQLite to the next. 4577*/ 4578const char *sqlite3_column_name(sqlite3_stmt*, int N); 4579const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4580 4581/* 4582** CAPI3REF: Source Of Data In A Query Result 4583** METHOD: sqlite3_stmt 4584** 4585** ^These routines provide a means to determine the database, table, and 4586** table column that is the origin of a particular result column in 4587** [SELECT] statement. 4588** ^The name of the database or table or column can be returned as 4589** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4590** the database name, the _table_ routines return the table name, and 4591** the origin_ routines return the column name. 4592** ^The returned string is valid until the [prepared statement] is destroyed 4593** using [sqlite3_finalize()] or until the statement is automatically 4594** reprepared by the first call to [sqlite3_step()] for a particular run 4595** or until the same information is requested 4596** again in a different encoding. 4597** 4598** ^The names returned are the original un-aliased names of the 4599** database, table, and column. 4600** 4601** ^The first argument to these interfaces is a [prepared statement]. 4602** ^These functions return information about the Nth result column returned by 4603** the statement, where N is the second function argument. 4604** ^The left-most column is column 0 for these routines. 4605** 4606** ^If the Nth column returned by the statement is an expression or 4607** subquery and is not a column value, then all of these functions return 4608** NULL. ^These routines might also return NULL if a memory allocation error 4609** occurs. ^Otherwise, they return the name of the attached database, table, 4610** or column that query result column was extracted from. 4611** 4612** ^As with all other SQLite APIs, those whose names end with "16" return 4613** UTF-16 encoded strings and the other functions return UTF-8. 4614** 4615** ^These APIs are only available if the library was compiled with the 4616** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4617** 4618** If two or more threads call one or more 4619** [sqlite3_column_database_name | column metadata interfaces] 4620** for the same [prepared statement] and result column 4621** at the same time then the results are undefined. 4622*/ 4623const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4624const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4625const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4626const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4627const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4628const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4629 4630/* 4631** CAPI3REF: Declared Datatype Of A Query Result 4632** METHOD: sqlite3_stmt 4633** 4634** ^(The first parameter is a [prepared statement]. 4635** If this statement is a [SELECT] statement and the Nth column of the 4636** returned result set of that [SELECT] is a table column (not an 4637** expression or subquery) then the declared type of the table 4638** column is returned.)^ ^If the Nth column of the result set is an 4639** expression or subquery, then a NULL pointer is returned. 4640** ^The returned string is always UTF-8 encoded. 4641** 4642** ^(For example, given the database schema: 4643** 4644** CREATE TABLE t1(c1 VARIANT); 4645** 4646** and the following statement to be compiled: 4647** 4648** SELECT c1 + 1, c1 FROM t1; 4649** 4650** this routine would return the string "VARIANT" for the second result 4651** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4652** 4653** ^SQLite uses dynamic run-time typing. ^So just because a column 4654** is declared to contain a particular type does not mean that the 4655** data stored in that column is of the declared type. SQLite is 4656** strongly typed, but the typing is dynamic not static. ^Type 4657** is associated with individual values, not with the containers 4658** used to hold those values. 4659*/ 4660const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4661const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4662 4663/* 4664** CAPI3REF: Evaluate An SQL Statement 4665** METHOD: sqlite3_stmt 4666** 4667** After a [prepared statement] has been prepared using any of 4668** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4669** or [sqlite3_prepare16_v3()] or one of the legacy 4670** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4671** must be called one or more times to evaluate the statement. 4672** 4673** The details of the behavior of the sqlite3_step() interface depend 4674** on whether the statement was prepared using the newer "vX" interfaces 4675** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4676** [sqlite3_prepare16_v2()] or the older legacy 4677** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4678** new "vX" interface is recommended for new applications but the legacy 4679** interface will continue to be supported. 4680** 4681** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4682** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4683** ^With the "v2" interface, any of the other [result codes] or 4684** [extended result codes] might be returned as well. 4685** 4686** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4687** database locks it needs to do its job. ^If the statement is a [COMMIT] 4688** or occurs outside of an explicit transaction, then you can retry the 4689** statement. If the statement is not a [COMMIT] and occurs within an 4690** explicit transaction then you should rollback the transaction before 4691** continuing. 4692** 4693** ^[SQLITE_DONE] means that the statement has finished executing 4694** successfully. sqlite3_step() should not be called again on this virtual 4695** machine without first calling [sqlite3_reset()] to reset the virtual 4696** machine back to its initial state. 4697** 4698** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4699** is returned each time a new row of data is ready for processing by the 4700** caller. The values may be accessed using the [column access functions]. 4701** sqlite3_step() is called again to retrieve the next row of data. 4702** 4703** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4704** violation) has occurred. sqlite3_step() should not be called again on 4705** the VM. More information may be found by calling [sqlite3_errmsg()]. 4706** ^With the legacy interface, a more specific error code (for example, 4707** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4708** can be obtained by calling [sqlite3_reset()] on the 4709** [prepared statement]. ^In the "v2" interface, 4710** the more specific error code is returned directly by sqlite3_step(). 4711** 4712** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4713** Perhaps it was called on a [prepared statement] that has 4714** already been [sqlite3_finalize | finalized] or on one that had 4715** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4716** be the case that the same database connection is being used by two or 4717** more threads at the same moment in time. 4718** 4719** For all versions of SQLite up to and including 3.6.23.1, a call to 4720** [sqlite3_reset()] was required after sqlite3_step() returned anything 4721** other than [SQLITE_ROW] before any subsequent invocation of 4722** sqlite3_step(). Failure to reset the prepared statement using 4723** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4724** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4725** sqlite3_step() began 4726** calling [sqlite3_reset()] automatically in this circumstance rather 4727** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4728** break because any application that ever receives an SQLITE_MISUSE error 4729** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4730** can be used to restore the legacy behavior. 4731** 4732** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4733** API always returns a generic error code, [SQLITE_ERROR], following any 4734** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4735** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4736** specific [error codes] that better describes the error. 4737** We admit that this is a goofy design. The problem has been fixed 4738** with the "v2" interface. If you prepare all of your SQL statements 4739** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4740** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4741** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4742** then the more specific [error codes] are returned directly 4743** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4744*/ 4745int sqlite3_step(sqlite3_stmt*); 4746 4747/* 4748** CAPI3REF: Number of columns in a result set 4749** METHOD: sqlite3_stmt 4750** 4751** ^The sqlite3_data_count(P) interface returns the number of columns in the 4752** current row of the result set of [prepared statement] P. 4753** ^If prepared statement P does not have results ready to return 4754** (via calls to the [sqlite3_column_int | sqlite3_column()] family of 4755** interfaces) then sqlite3_data_count(P) returns 0. 4756** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4757** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4758** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4759** will return non-zero if previous call to [sqlite3_step](P) returned 4760** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4761** where it always returns zero since each step of that multi-step 4762** pragma returns 0 columns of data. 4763** 4764** See also: [sqlite3_column_count()] 4765*/ 4766int sqlite3_data_count(sqlite3_stmt *pStmt); 4767 4768/* 4769** CAPI3REF: Fundamental Datatypes 4770** KEYWORDS: SQLITE_TEXT 4771** 4772** ^(Every value in SQLite has one of five fundamental datatypes: 4773** 4774** <ul> 4775** <li> 64-bit signed integer 4776** <li> 64-bit IEEE floating point number 4777** <li> string 4778** <li> BLOB 4779** <li> NULL 4780** </ul>)^ 4781** 4782** These constants are codes for each of those types. 4783** 4784** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4785** for a completely different meaning. Software that links against both 4786** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4787** SQLITE_TEXT. 4788*/ 4789#define SQLITE_INTEGER 1 4790#define SQLITE_FLOAT 2 4791#define SQLITE_BLOB 4 4792#define SQLITE_NULL 5 4793#ifdef SQLITE_TEXT 4794# undef SQLITE_TEXT 4795#else 4796# define SQLITE_TEXT 3 4797#endif 4798#define SQLITE3_TEXT 3 4799 4800/* 4801** CAPI3REF: Result Values From A Query 4802** KEYWORDS: {column access functions} 4803** METHOD: sqlite3_stmt 4804** 4805** <b>Summary:</b> 4806** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4807** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4808** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4809** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4810** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4811** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4812** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4813** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4814** [sqlite3_value|unprotected sqlite3_value] object. 4815** <tr><td> <td> <td> 4816** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4817** or a UTF-8 TEXT result in bytes 4818** <tr><td><b>sqlite3_column_bytes16 </b> 4819** <td>→ <td>Size of UTF-16 4820** TEXT in bytes 4821** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4822** datatype of the result 4823** </table></blockquote> 4824** 4825** <b>Details:</b> 4826** 4827** ^These routines return information about a single column of the current 4828** result row of a query. ^In every case the first argument is a pointer 4829** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4830** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4831** and the second argument is the index of the column for which information 4832** should be returned. ^The leftmost column of the result set has the index 0. 4833** ^The number of columns in the result can be determined using 4834** [sqlite3_column_count()]. 4835** 4836** If the SQL statement does not currently point to a valid row, or if the 4837** column index is out of range, the result is undefined. 4838** These routines may only be called when the most recent call to 4839** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4840** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4841** If any of these routines are called after [sqlite3_reset()] or 4842** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4843** something other than [SQLITE_ROW], the results are undefined. 4844** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4845** are called from a different thread while any of these routines 4846** are pending, then the results are undefined. 4847** 4848** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4849** each return the value of a result column in a specific data format. If 4850** the result column is not initially in the requested format (for example, 4851** if the query returns an integer but the sqlite3_column_text() interface 4852** is used to extract the value) then an automatic type conversion is performed. 4853** 4854** ^The sqlite3_column_type() routine returns the 4855** [SQLITE_INTEGER | datatype code] for the initial data type 4856** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4857** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4858** The return value of sqlite3_column_type() can be used to decide which 4859** of the first six interface should be used to extract the column value. 4860** The value returned by sqlite3_column_type() is only meaningful if no 4861** automatic type conversions have occurred for the value in question. 4862** After a type conversion, the result of calling sqlite3_column_type() 4863** is undefined, though harmless. Future 4864** versions of SQLite may change the behavior of sqlite3_column_type() 4865** following a type conversion. 4866** 4867** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4868** or sqlite3_column_bytes16() interfaces can be used to determine the size 4869** of that BLOB or string. 4870** 4871** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4872** routine returns the number of bytes in that BLOB or string. 4873** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4874** the string to UTF-8 and then returns the number of bytes. 4875** ^If the result is a numeric value then sqlite3_column_bytes() uses 4876** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4877** the number of bytes in that string. 4878** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4879** 4880** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4881** routine returns the number of bytes in that BLOB or string. 4882** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4883** the string to UTF-16 and then returns the number of bytes. 4884** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4885** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4886** the number of bytes in that string. 4887** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4888** 4889** ^The values returned by [sqlite3_column_bytes()] and 4890** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4891** of the string. ^For clarity: the values returned by 4892** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4893** bytes in the string, not the number of characters. 4894** 4895** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4896** even empty strings, are always zero-terminated. ^The return 4897** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4898** 4899** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4900** [unprotected sqlite3_value] object. In a multithreaded environment, 4901** an unprotected sqlite3_value object may only be used safely with 4902** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4903** If the [unprotected sqlite3_value] object returned by 4904** [sqlite3_column_value()] is used in any other way, including calls 4905** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4906** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4907** Hence, the sqlite3_column_value() interface 4908** is normally only useful within the implementation of 4909** [application-defined SQL functions] or [virtual tables], not within 4910** top-level application code. 4911** 4912** The these routines may attempt to convert the datatype of the result. 4913** ^For example, if the internal representation is FLOAT and a text result 4914** is requested, [sqlite3_snprintf()] is used internally to perform the 4915** conversion automatically. ^(The following table details the conversions 4916** that are applied: 4917** 4918** <blockquote> 4919** <table border="1"> 4920** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4921** 4922** <tr><td> NULL <td> INTEGER <td> Result is 0 4923** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4924** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4925** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4926** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4927** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4928** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4929** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4930** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4931** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4932** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4933** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4934** <tr><td> TEXT <td> BLOB <td> No change 4935** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4936** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4937** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4938** </table> 4939** </blockquote>)^ 4940** 4941** Note that when type conversions occur, pointers returned by prior 4942** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4943** sqlite3_column_text16() may be invalidated. 4944** Type conversions and pointer invalidations might occur 4945** in the following cases: 4946** 4947** <ul> 4948** <li> The initial content is a BLOB and sqlite3_column_text() or 4949** sqlite3_column_text16() is called. A zero-terminator might 4950** need to be added to the string.</li> 4951** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4952** sqlite3_column_text16() is called. The content must be converted 4953** to UTF-16.</li> 4954** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4955** sqlite3_column_text() is called. The content must be converted 4956** to UTF-8.</li> 4957** </ul> 4958** 4959** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4960** not invalidate a prior pointer, though of course the content of the buffer 4961** that the prior pointer references will have been modified. Other kinds 4962** of conversion are done in place when it is possible, but sometimes they 4963** are not possible and in those cases prior pointers are invalidated. 4964** 4965** The safest policy is to invoke these routines 4966** in one of the following ways: 4967** 4968** <ul> 4969** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4970** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4971** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4972** </ul> 4973** 4974** In other words, you should call sqlite3_column_text(), 4975** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4976** into the desired format, then invoke sqlite3_column_bytes() or 4977** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4978** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4979** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4980** with calls to sqlite3_column_bytes(). 4981** 4982** ^The pointers returned are valid until a type conversion occurs as 4983** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4984** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4985** and BLOBs is freed automatically. Do not pass the pointers returned 4986** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4987** [sqlite3_free()]. 4988** 4989** As long as the input parameters are correct, these routines will only 4990** fail if an out-of-memory error occurs during a format conversion. 4991** Only the following subset of interfaces are subject to out-of-memory 4992** errors: 4993** 4994** <ul> 4995** <li> sqlite3_column_blob() 4996** <li> sqlite3_column_text() 4997** <li> sqlite3_column_text16() 4998** <li> sqlite3_column_bytes() 4999** <li> sqlite3_column_bytes16() 5000** </ul> 5001** 5002** If an out-of-memory error occurs, then the return value from these 5003** routines is the same as if the column had contained an SQL NULL value. 5004** Valid SQL NULL returns can be distinguished from out-of-memory errors 5005** by invoking the [sqlite3_errcode()] immediately after the suspect 5006** return value is obtained and before any 5007** other SQLite interface is called on the same [database connection]. 5008*/ 5009const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 5010double sqlite3_column_double(sqlite3_stmt*, int iCol); 5011int sqlite3_column_int(sqlite3_stmt*, int iCol); 5012sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 5013const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 5014const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 5015sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 5016int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 5017int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 5018int sqlite3_column_type(sqlite3_stmt*, int iCol); 5019 5020/* 5021** CAPI3REF: Destroy A Prepared Statement Object 5022** DESTRUCTOR: sqlite3_stmt 5023** 5024** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 5025** ^If the most recent evaluation of the statement encountered no errors 5026** or if the statement is never been evaluated, then sqlite3_finalize() returns 5027** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 5028** sqlite3_finalize(S) returns the appropriate [error code] or 5029** [extended error code]. 5030** 5031** ^The sqlite3_finalize(S) routine can be called at any point during 5032** the life cycle of [prepared statement] S: 5033** before statement S is ever evaluated, after 5034** one or more calls to [sqlite3_reset()], or after any call 5035** to [sqlite3_step()] regardless of whether or not the statement has 5036** completed execution. 5037** 5038** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 5039** 5040** The application must finalize every [prepared statement] in order to avoid 5041** resource leaks. It is a grievous error for the application to try to use 5042** a prepared statement after it has been finalized. Any use of a prepared 5043** statement after it has been finalized can result in undefined and 5044** undesirable behavior such as segfaults and heap corruption. 5045*/ 5046int sqlite3_finalize(sqlite3_stmt *pStmt); 5047 5048/* 5049** CAPI3REF: Reset A Prepared Statement Object 5050** METHOD: sqlite3_stmt 5051** 5052** The sqlite3_reset() function is called to reset a [prepared statement] 5053** object back to its initial state, ready to be re-executed. 5054** ^Any SQL statement variables that had values bound to them using 5055** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 5056** Use [sqlite3_clear_bindings()] to reset the bindings. 5057** 5058** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 5059** back to the beginning of its program. 5060** 5061** ^If the most recent call to [sqlite3_step(S)] for the 5062** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 5063** or if [sqlite3_step(S)] has never before been called on S, 5064** then [sqlite3_reset(S)] returns [SQLITE_OK]. 5065** 5066** ^If the most recent call to [sqlite3_step(S)] for the 5067** [prepared statement] S indicated an error, then 5068** [sqlite3_reset(S)] returns an appropriate [error code]. 5069** 5070** ^The [sqlite3_reset(S)] interface does not change the values 5071** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 5072*/ 5073int sqlite3_reset(sqlite3_stmt *pStmt); 5074 5075/* 5076** CAPI3REF: Create Or Redefine SQL Functions 5077** KEYWORDS: {function creation routines} 5078** METHOD: sqlite3 5079** 5080** ^These functions (collectively known as "function creation routines") 5081** are used to add SQL functions or aggregates or to redefine the behavior 5082** of existing SQL functions or aggregates. The only differences between 5083** the three "sqlite3_create_function*" routines are the text encoding 5084** expected for the second parameter (the name of the function being 5085** created) and the presence or absence of a destructor callback for 5086** the application data pointer. Function sqlite3_create_window_function() 5087** is similar, but allows the user to supply the extra callback functions 5088** needed by [aggregate window functions]. 5089** 5090** ^The first parameter is the [database connection] to which the SQL 5091** function is to be added. ^If an application uses more than one database 5092** connection then application-defined SQL functions must be added 5093** to each database connection separately. 5094** 5095** ^The second parameter is the name of the SQL function to be created or 5096** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 5097** representation, exclusive of the zero-terminator. ^Note that the name 5098** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 5099** ^Any attempt to create a function with a longer name 5100** will result in [SQLITE_MISUSE] being returned. 5101** 5102** ^The third parameter (nArg) 5103** is the number of arguments that the SQL function or 5104** aggregate takes. ^If this parameter is -1, then the SQL function or 5105** aggregate may take any number of arguments between 0 and the limit 5106** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 5107** parameter is less than -1 or greater than 127 then the behavior is 5108** undefined. 5109** 5110** ^The fourth parameter, eTextRep, specifies what 5111** [SQLITE_UTF8 | text encoding] this SQL function prefers for 5112** its parameters. The application should set this parameter to 5113** [SQLITE_UTF16LE] if the function implementation invokes 5114** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 5115** implementation invokes [sqlite3_value_text16be()] on an input, or 5116** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 5117** otherwise. ^The same SQL function may be registered multiple times using 5118** different preferred text encodings, with different implementations for 5119** each encoding. 5120** ^When multiple implementations of the same function are available, SQLite 5121** will pick the one that involves the least amount of data conversion. 5122** 5123** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 5124** to signal that the function will always return the same result given 5125** the same inputs within a single SQL statement. Most SQL functions are 5126** deterministic. The built-in [random()] SQL function is an example of a 5127** function that is not deterministic. The SQLite query planner is able to 5128** perform additional optimizations on deterministic functions, so use 5129** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 5130** 5131** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY] 5132** flag, which if present prevents the function from being invoked from 5133** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions, 5134** index expressions, or the WHERE clause of partial indexes. 5135** 5136** <span style="background-color:#ffff90;"> 5137** For best security, the [SQLITE_DIRECTONLY] flag is recommended for 5138** all application-defined SQL functions that do not need to be 5139** used inside of triggers, view, CHECK constraints, or other elements of 5140** the database schema. This flags is especially recommended for SQL 5141** functions that have side effects or reveal internal application state. 5142** Without this flag, an attacker might be able to modify the schema of 5143** a database file to include invocations of the function with parameters 5144** chosen by the attacker, which the application will then execute when 5145** the database file is opened and read. 5146** </span> 5147** 5148** ^(The fifth parameter is an arbitrary pointer. The implementation of the 5149** function can gain access to this pointer using [sqlite3_user_data()].)^ 5150** 5151** ^The sixth, seventh and eighth parameters passed to the three 5152** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are 5153** pointers to C-language functions that implement the SQL function or 5154** aggregate. ^A scalar SQL function requires an implementation of the xFunc 5155** callback only; NULL pointers must be passed as the xStep and xFinal 5156** parameters. ^An aggregate SQL function requires an implementation of xStep 5157** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 5158** SQL function or aggregate, pass NULL pointers for all three function 5159** callbacks. 5160** 5161** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue 5162** and xInverse) passed to sqlite3_create_window_function are pointers to 5163** C-language callbacks that implement the new function. xStep and xFinal 5164** must both be non-NULL. xValue and xInverse may either both be NULL, in 5165** which case a regular aggregate function is created, or must both be 5166** non-NULL, in which case the new function may be used as either an aggregate 5167** or aggregate window function. More details regarding the implementation 5168** of aggregate window functions are 5169** [user-defined window functions|available here]. 5170** 5171** ^(If the final parameter to sqlite3_create_function_v2() or 5172** sqlite3_create_window_function() is not NULL, then it is destructor for 5173** the application data pointer. The destructor is invoked when the function 5174** is deleted, either by being overloaded or when the database connection 5175** closes.)^ ^The destructor is also invoked if the call to 5176** sqlite3_create_function_v2() fails. ^When the destructor callback is 5177** invoked, it is passed a single argument which is a copy of the application 5178** data pointer which was the fifth parameter to sqlite3_create_function_v2(). 5179** 5180** ^It is permitted to register multiple implementations of the same 5181** functions with the same name but with either differing numbers of 5182** arguments or differing preferred text encodings. ^SQLite will use 5183** the implementation that most closely matches the way in which the 5184** SQL function is used. ^A function implementation with a non-negative 5185** nArg parameter is a better match than a function implementation with 5186** a negative nArg. ^A function where the preferred text encoding 5187** matches the database encoding is a better 5188** match than a function where the encoding is different. 5189** ^A function where the encoding difference is between UTF16le and UTF16be 5190** is a closer match than a function where the encoding difference is 5191** between UTF8 and UTF16. 5192** 5193** ^Built-in functions may be overloaded by new application-defined functions. 5194** 5195** ^An application-defined function is permitted to call other 5196** SQLite interfaces. However, such calls must not 5197** close the database connection nor finalize or reset the prepared 5198** statement in which the function is running. 5199*/ 5200int sqlite3_create_function( 5201 sqlite3 *db, 5202 const char *zFunctionName, 5203 int nArg, 5204 int eTextRep, 5205 void *pApp, 5206 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5207 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5208 void (*xFinal)(sqlite3_context*) 5209); 5210int sqlite3_create_function16( 5211 sqlite3 *db, 5212 const void *zFunctionName, 5213 int nArg, 5214 int eTextRep, 5215 void *pApp, 5216 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5217 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5218 void (*xFinal)(sqlite3_context*) 5219); 5220int sqlite3_create_function_v2( 5221 sqlite3 *db, 5222 const char *zFunctionName, 5223 int nArg, 5224 int eTextRep, 5225 void *pApp, 5226 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5227 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5228 void (*xFinal)(sqlite3_context*), 5229 void(*xDestroy)(void*) 5230); 5231int sqlite3_create_window_function( 5232 sqlite3 *db, 5233 const char *zFunctionName, 5234 int nArg, 5235 int eTextRep, 5236 void *pApp, 5237 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5238 void (*xFinal)(sqlite3_context*), 5239 void (*xValue)(sqlite3_context*), 5240 void (*xInverse)(sqlite3_context*,int,sqlite3_value**), 5241 void(*xDestroy)(void*) 5242); 5243 5244/* 5245** CAPI3REF: Text Encodings 5246** 5247** These constant define integer codes that represent the various 5248** text encodings supported by SQLite. 5249*/ 5250#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 5251#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 5252#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 5253#define SQLITE_UTF16 4 /* Use native byte order */ 5254#define SQLITE_ANY 5 /* Deprecated */ 5255#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 5256 5257/* 5258** CAPI3REF: Function Flags 5259** 5260** These constants may be ORed together with the 5261** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 5262** to [sqlite3_create_function()], [sqlite3_create_function16()], or 5263** [sqlite3_create_function_v2()]. 5264** 5265** <dl> 5266** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd> 5267** The SQLITE_DETERMINISTIC flag means that the new function always gives 5268** the same output when the input parameters are the same. 5269** The [abs|abs() function] is deterministic, for example, but 5270** [randomblob|randomblob()] is not. Functions must 5271** be deterministic in order to be used in certain contexts such as 5272** with the WHERE clause of [partial indexes] or in [generated columns]. 5273** SQLite might also optimize deterministic functions by factoring them 5274** out of inner loops. 5275** </dd> 5276** 5277** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd> 5278** The SQLITE_DIRECTONLY flag means that the function may only be invoked 5279** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in 5280** schema structures such as [CHECK constraints], [DEFAULT clauses], 5281** [expression indexes], [partial indexes], or [generated columns]. 5282** The SQLITE_DIRECTONLY flags is a security feature which is recommended 5283** for all [application-defined SQL functions], and especially for functions 5284** that have side-effects or that could potentially leak sensitive 5285** information. 5286** </dd> 5287** 5288** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd> 5289** The SQLITE_INNOCUOUS flag means that the function is unlikely 5290** to cause problems even if misused. An innocuous function should have 5291** no side effects and should not depend on any values other than its 5292** input parameters. The [abs|abs() function] is an example of an 5293** innocuous function. 5294** The [load_extension() SQL function] is not innocuous because of its 5295** side effects. 5296** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not 5297** exactly the same. The [random|random() function] is an example of a 5298** function that is innocuous but not deterministic. 5299** <p>Some heightened security settings 5300** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF]) 5301** disable the use of SQL functions inside views and triggers and in 5302** schema structures such as [CHECK constraints], [DEFAULT clauses], 5303** [expression indexes], [partial indexes], and [generated columns] unless 5304** the function is tagged with SQLITE_INNOCUOUS. Most built-in functions 5305** are innocuous. Developers are advised to avoid using the 5306** SQLITE_INNOCUOUS flag for application-defined functions unless the 5307** function has been carefully audited and found to be free of potentially 5308** security-adverse side-effects and information-leaks. 5309** </dd> 5310** 5311** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd> 5312** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call 5313** [sqlite3_value_subtype()] to inspect the sub-types of its arguments. 5314** Specifying this flag makes no difference for scalar or aggregate user 5315** functions. However, if it is not specified for a user-defined window 5316** function, then any sub-types belonging to arguments passed to the window 5317** function may be discarded before the window function is called (i.e. 5318** sqlite3_value_subtype() will always return 0). 5319** </dd> 5320** </dl> 5321*/ 5322#define SQLITE_DETERMINISTIC 0x000000800 5323#define SQLITE_DIRECTONLY 0x000080000 5324#define SQLITE_SUBTYPE 0x000100000 5325#define SQLITE_INNOCUOUS 0x000200000 5326 5327/* 5328** CAPI3REF: Deprecated Functions 5329** DEPRECATED 5330** 5331** These functions are [deprecated]. In order to maintain 5332** backwards compatibility with older code, these functions continue 5333** to be supported. However, new applications should avoid 5334** the use of these functions. To encourage programmers to avoid 5335** these functions, we will not explain what they do. 5336*/ 5337#ifndef SQLITE_OMIT_DEPRECATED 5338SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 5339SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 5340SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 5341SQLITE_DEPRECATED int sqlite3_global_recover(void); 5342SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 5343SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 5344 void*,sqlite3_int64); 5345#endif 5346 5347/* 5348** CAPI3REF: Obtaining SQL Values 5349** METHOD: sqlite3_value 5350** 5351** <b>Summary:</b> 5352** <blockquote><table border=0 cellpadding=0 cellspacing=0> 5353** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 5354** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 5355** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 5356** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 5357** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 5358** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 5359** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 5360** the native byteorder 5361** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 5362** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 5363** <tr><td> <td> <td> 5364** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 5365** or a UTF-8 TEXT in bytes 5366** <tr><td><b>sqlite3_value_bytes16 </b> 5367** <td>→ <td>Size of UTF-16 5368** TEXT in bytes 5369** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 5370** datatype of the value 5371** <tr><td><b>sqlite3_value_numeric_type </b> 5372** <td>→ <td>Best numeric datatype of the value 5373** <tr><td><b>sqlite3_value_nochange </b> 5374** <td>→ <td>True if the column is unchanged in an UPDATE 5375** against a virtual table. 5376** <tr><td><b>sqlite3_value_frombind </b> 5377** <td>→ <td>True if value originated from a [bound parameter] 5378** </table></blockquote> 5379** 5380** <b>Details:</b> 5381** 5382** These routines extract type, size, and content information from 5383** [protected sqlite3_value] objects. Protected sqlite3_value objects 5384** are used to pass parameter information into the functions that 5385** implement [application-defined SQL functions] and [virtual tables]. 5386** 5387** These routines work only with [protected sqlite3_value] objects. 5388** Any attempt to use these routines on an [unprotected sqlite3_value] 5389** is not threadsafe. 5390** 5391** ^These routines work just like the corresponding [column access functions] 5392** except that these routines take a single [protected sqlite3_value] object 5393** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 5394** 5395** ^The sqlite3_value_text16() interface extracts a UTF-16 string 5396** in the native byte-order of the host machine. ^The 5397** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 5398** extract UTF-16 strings as big-endian and little-endian respectively. 5399** 5400** ^If [sqlite3_value] object V was initialized 5401** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 5402** and if X and Y are strings that compare equal according to strcmp(X,Y), 5403** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 5404** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 5405** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5406** 5407** ^(The sqlite3_value_type(V) interface returns the 5408** [SQLITE_INTEGER | datatype code] for the initial datatype of the 5409** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 5410** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 5411** Other interfaces might change the datatype for an sqlite3_value object. 5412** For example, if the datatype is initially SQLITE_INTEGER and 5413** sqlite3_value_text(V) is called to extract a text value for that 5414** integer, then subsequent calls to sqlite3_value_type(V) might return 5415** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 5416** occurs is undefined and may change from one release of SQLite to the next. 5417** 5418** ^(The sqlite3_value_numeric_type() interface attempts to apply 5419** numeric affinity to the value. This means that an attempt is 5420** made to convert the value to an integer or floating point. If 5421** such a conversion is possible without loss of information (in other 5422** words, if the value is a string that looks like a number) 5423** then the conversion is performed. Otherwise no conversion occurs. 5424** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 5425** 5426** ^Within the [xUpdate] method of a [virtual table], the 5427** sqlite3_value_nochange(X) interface returns true if and only if 5428** the column corresponding to X is unchanged by the UPDATE operation 5429** that the xUpdate method call was invoked to implement and if 5430** and the prior [xColumn] method call that was invoked to extracted 5431** the value for that column returned without setting a result (probably 5432** because it queried [sqlite3_vtab_nochange()] and found that the column 5433** was unchanging). ^Within an [xUpdate] method, any value for which 5434** sqlite3_value_nochange(X) is true will in all other respects appear 5435** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 5436** than within an [xUpdate] method call for an UPDATE statement, then 5437** the return value is arbitrary and meaningless. 5438** 5439** ^The sqlite3_value_frombind(X) interface returns non-zero if the 5440** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()] 5441** interfaces. ^If X comes from an SQL literal value, or a table column, 5442** or an expression, then sqlite3_value_frombind(X) returns zero. 5443** 5444** Please pay particular attention to the fact that the pointer returned 5445** from [sqlite3_value_blob()], [sqlite3_value_text()], or 5446** [sqlite3_value_text16()] can be invalidated by a subsequent call to 5447** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 5448** or [sqlite3_value_text16()]. 5449** 5450** These routines must be called from the same thread as 5451** the SQL function that supplied the [sqlite3_value*] parameters. 5452** 5453** As long as the input parameter is correct, these routines can only 5454** fail if an out-of-memory error occurs during a format conversion. 5455** Only the following subset of interfaces are subject to out-of-memory 5456** errors: 5457** 5458** <ul> 5459** <li> sqlite3_value_blob() 5460** <li> sqlite3_value_text() 5461** <li> sqlite3_value_text16() 5462** <li> sqlite3_value_text16le() 5463** <li> sqlite3_value_text16be() 5464** <li> sqlite3_value_bytes() 5465** <li> sqlite3_value_bytes16() 5466** </ul> 5467** 5468** If an out-of-memory error occurs, then the return value from these 5469** routines is the same as if the column had contained an SQL NULL value. 5470** Valid SQL NULL returns can be distinguished from out-of-memory errors 5471** by invoking the [sqlite3_errcode()] immediately after the suspect 5472** return value is obtained and before any 5473** other SQLite interface is called on the same [database connection]. 5474*/ 5475const void *sqlite3_value_blob(sqlite3_value*); 5476double sqlite3_value_double(sqlite3_value*); 5477int sqlite3_value_int(sqlite3_value*); 5478sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 5479void *sqlite3_value_pointer(sqlite3_value*, const char*); 5480const unsigned char *sqlite3_value_text(sqlite3_value*); 5481const void *sqlite3_value_text16(sqlite3_value*); 5482const void *sqlite3_value_text16le(sqlite3_value*); 5483const void *sqlite3_value_text16be(sqlite3_value*); 5484int sqlite3_value_bytes(sqlite3_value*); 5485int sqlite3_value_bytes16(sqlite3_value*); 5486int sqlite3_value_type(sqlite3_value*); 5487int sqlite3_value_numeric_type(sqlite3_value*); 5488int sqlite3_value_nochange(sqlite3_value*); 5489int sqlite3_value_frombind(sqlite3_value*); 5490 5491/* 5492** CAPI3REF: Finding The Subtype Of SQL Values 5493** METHOD: sqlite3_value 5494** 5495** The sqlite3_value_subtype(V) function returns the subtype for 5496** an [application-defined SQL function] argument V. The subtype 5497** information can be used to pass a limited amount of context from 5498** one SQL function to another. Use the [sqlite3_result_subtype()] 5499** routine to set the subtype for the return value of an SQL function. 5500*/ 5501unsigned int sqlite3_value_subtype(sqlite3_value*); 5502 5503/* 5504** CAPI3REF: Copy And Free SQL Values 5505** METHOD: sqlite3_value 5506** 5507** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 5508** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 5509** is a [protected sqlite3_value] object even if the input is not. 5510** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 5511** memory allocation fails. 5512** 5513** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 5514** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 5515** then sqlite3_value_free(V) is a harmless no-op. 5516*/ 5517sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 5518void sqlite3_value_free(sqlite3_value*); 5519 5520/* 5521** CAPI3REF: Obtain Aggregate Function Context 5522** METHOD: sqlite3_context 5523** 5524** Implementations of aggregate SQL functions use this 5525** routine to allocate memory for storing their state. 5526** 5527** ^The first time the sqlite3_aggregate_context(C,N) routine is called 5528** for a particular aggregate function, SQLite allocates 5529** N bytes of memory, zeroes out that memory, and returns a pointer 5530** to the new memory. ^On second and subsequent calls to 5531** sqlite3_aggregate_context() for the same aggregate function instance, 5532** the same buffer is returned. Sqlite3_aggregate_context() is normally 5533** called once for each invocation of the xStep callback and then one 5534** last time when the xFinal callback is invoked. ^(When no rows match 5535** an aggregate query, the xStep() callback of the aggregate function 5536** implementation is never called and xFinal() is called exactly once. 5537** In those cases, sqlite3_aggregate_context() might be called for the 5538** first time from within xFinal().)^ 5539** 5540** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 5541** when first called if N is less than or equal to zero or if a memory 5542** allocate error occurs. 5543** 5544** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 5545** determined by the N parameter on first successful call. Changing the 5546** value of N in any subsequent call to sqlite3_aggregate_context() within 5547** the same aggregate function instance will not resize the memory 5548** allocation.)^ Within the xFinal callback, it is customary to set 5549** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 5550** pointless memory allocations occur. 5551** 5552** ^SQLite automatically frees the memory allocated by 5553** sqlite3_aggregate_context() when the aggregate query concludes. 5554** 5555** The first parameter must be a copy of the 5556** [sqlite3_context | SQL function context] that is the first parameter 5557** to the xStep or xFinal callback routine that implements the aggregate 5558** function. 5559** 5560** This routine must be called from the same thread in which 5561** the aggregate SQL function is running. 5562*/ 5563void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 5564 5565/* 5566** CAPI3REF: User Data For Functions 5567** METHOD: sqlite3_context 5568** 5569** ^The sqlite3_user_data() interface returns a copy of 5570** the pointer that was the pUserData parameter (the 5th parameter) 5571** of the [sqlite3_create_function()] 5572** and [sqlite3_create_function16()] routines that originally 5573** registered the application defined function. 5574** 5575** This routine must be called from the same thread in which 5576** the application-defined function is running. 5577*/ 5578void *sqlite3_user_data(sqlite3_context*); 5579 5580/* 5581** CAPI3REF: Database Connection For Functions 5582** METHOD: sqlite3_context 5583** 5584** ^The sqlite3_context_db_handle() interface returns a copy of 5585** the pointer to the [database connection] (the 1st parameter) 5586** of the [sqlite3_create_function()] 5587** and [sqlite3_create_function16()] routines that originally 5588** registered the application defined function. 5589*/ 5590sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 5591 5592/* 5593** CAPI3REF: Function Auxiliary Data 5594** METHOD: sqlite3_context 5595** 5596** These functions may be used by (non-aggregate) SQL functions to 5597** associate metadata with argument values. If the same value is passed to 5598** multiple invocations of the same SQL function during query execution, under 5599** some circumstances the associated metadata may be preserved. An example 5600** of where this might be useful is in a regular-expression matching 5601** function. The compiled version of the regular expression can be stored as 5602** metadata associated with the pattern string. 5603** Then as long as the pattern string remains the same, 5604** the compiled regular expression can be reused on multiple 5605** invocations of the same function. 5606** 5607** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 5608** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 5609** value to the application-defined function. ^N is zero for the left-most 5610** function argument. ^If there is no metadata 5611** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 5612** returns a NULL pointer. 5613** 5614** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 5615** argument of the application-defined function. ^Subsequent 5616** calls to sqlite3_get_auxdata(C,N) return P from the most recent 5617** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5618** NULL if the metadata has been discarded. 5619** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5620** SQLite will invoke the destructor function X with parameter P exactly 5621** once, when the metadata is discarded. 5622** SQLite is free to discard the metadata at any time, including: <ul> 5623** <li> ^(when the corresponding function parameter changes)^, or 5624** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5625** SQL statement)^, or 5626** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5627** parameter)^, or 5628** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5629** allocation error occurs.)^ </ul> 5630** 5631** Note the last bullet in particular. The destructor X in 5632** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5633** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5634** should be called near the end of the function implementation and the 5635** function implementation should not make any use of P after 5636** sqlite3_set_auxdata() has been called. 5637** 5638** ^(In practice, metadata is preserved between function calls for 5639** function parameters that are compile-time constants, including literal 5640** values and [parameters] and expressions composed from the same.)^ 5641** 5642** The value of the N parameter to these interfaces should be non-negative. 5643** Future enhancements may make use of negative N values to define new 5644** kinds of function caching behavior. 5645** 5646** These routines must be called from the same thread in which 5647** the SQL function is running. 5648*/ 5649void *sqlite3_get_auxdata(sqlite3_context*, int N); 5650void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5651 5652 5653/* 5654** CAPI3REF: Constants Defining Special Destructor Behavior 5655** 5656** These are special values for the destructor that is passed in as the 5657** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5658** argument is SQLITE_STATIC, it means that the content pointer is constant 5659** and will never change. It does not need to be destroyed. ^The 5660** SQLITE_TRANSIENT value means that the content will likely change in 5661** the near future and that SQLite should make its own private copy of 5662** the content before returning. 5663** 5664** The typedef is necessary to work around problems in certain 5665** C++ compilers. 5666*/ 5667typedef void (*sqlite3_destructor_type)(void*); 5668#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5669#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5670 5671/* 5672** CAPI3REF: Setting The Result Of An SQL Function 5673** METHOD: sqlite3_context 5674** 5675** These routines are used by the xFunc or xFinal callbacks that 5676** implement SQL functions and aggregates. See 5677** [sqlite3_create_function()] and [sqlite3_create_function16()] 5678** for additional information. 5679** 5680** These functions work very much like the [parameter binding] family of 5681** functions used to bind values to host parameters in prepared statements. 5682** Refer to the [SQL parameter] documentation for additional information. 5683** 5684** ^The sqlite3_result_blob() interface sets the result from 5685** an application-defined function to be the BLOB whose content is pointed 5686** to by the second parameter and which is N bytes long where N is the 5687** third parameter. 5688** 5689** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5690** interfaces set the result of the application-defined function to be 5691** a BLOB containing all zero bytes and N bytes in size. 5692** 5693** ^The sqlite3_result_double() interface sets the result from 5694** an application-defined function to be a floating point value specified 5695** by its 2nd argument. 5696** 5697** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5698** cause the implemented SQL function to throw an exception. 5699** ^SQLite uses the string pointed to by the 5700** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5701** as the text of an error message. ^SQLite interprets the error 5702** message string from sqlite3_result_error() as UTF-8. ^SQLite 5703** interprets the string from sqlite3_result_error16() as UTF-16 using 5704** the same [byte-order determination rules] as [sqlite3_bind_text16()]. 5705** ^If the third parameter to sqlite3_result_error() 5706** or sqlite3_result_error16() is negative then SQLite takes as the error 5707** message all text up through the first zero character. 5708** ^If the third parameter to sqlite3_result_error() or 5709** sqlite3_result_error16() is non-negative then SQLite takes that many 5710** bytes (not characters) from the 2nd parameter as the error message. 5711** ^The sqlite3_result_error() and sqlite3_result_error16() 5712** routines make a private copy of the error message text before 5713** they return. Hence, the calling function can deallocate or 5714** modify the text after they return without harm. 5715** ^The sqlite3_result_error_code() function changes the error code 5716** returned by SQLite as a result of an error in a function. ^By default, 5717** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5718** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5719** 5720** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5721** error indicating that a string or BLOB is too long to represent. 5722** 5723** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5724** error indicating that a memory allocation failed. 5725** 5726** ^The sqlite3_result_int() interface sets the return value 5727** of the application-defined function to be the 32-bit signed integer 5728** value given in the 2nd argument. 5729** ^The sqlite3_result_int64() interface sets the return value 5730** of the application-defined function to be the 64-bit signed integer 5731** value given in the 2nd argument. 5732** 5733** ^The sqlite3_result_null() interface sets the return value 5734** of the application-defined function to be NULL. 5735** 5736** ^The sqlite3_result_text(), sqlite3_result_text16(), 5737** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5738** set the return value of the application-defined function to be 5739** a text string which is represented as UTF-8, UTF-16 native byte order, 5740** UTF-16 little endian, or UTF-16 big endian, respectively. 5741** ^The sqlite3_result_text64() interface sets the return value of an 5742** application-defined function to be a text string in an encoding 5743** specified by the fifth (and last) parameter, which must be one 5744** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5745** ^SQLite takes the text result from the application from 5746** the 2nd parameter of the sqlite3_result_text* interfaces. 5747** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5748** is negative, then SQLite takes result text from the 2nd parameter 5749** through the first zero character. 5750** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5751** is non-negative, then as many bytes (not characters) of the text 5752** pointed to by the 2nd parameter are taken as the application-defined 5753** function result. If the 3rd parameter is non-negative, then it 5754** must be the byte offset into the string where the NUL terminator would 5755** appear if the string where NUL terminated. If any NUL characters occur 5756** in the string at a byte offset that is less than the value of the 3rd 5757** parameter, then the resulting string will contain embedded NULs and the 5758** result of expressions operating on strings with embedded NULs is undefined. 5759** ^If the 4th parameter to the sqlite3_result_text* interfaces 5760** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5761** function as the destructor on the text or BLOB result when it has 5762** finished using that result. 5763** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5764** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5765** assumes that the text or BLOB result is in constant space and does not 5766** copy the content of the parameter nor call a destructor on the content 5767** when it has finished using that result. 5768** ^If the 4th parameter to the sqlite3_result_text* interfaces 5769** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5770** then SQLite makes a copy of the result into space obtained 5771** from [sqlite3_malloc()] before it returns. 5772** 5773** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and 5774** sqlite3_result_text16be() routines, and for sqlite3_result_text64() 5775** when the encoding is not UTF8, if the input UTF16 begins with a 5776** byte-order mark (BOM, U+FEFF) then the BOM is removed from the 5777** string and the rest of the string is interpreted according to the 5778** byte-order specified by the BOM. ^The byte-order specified by 5779** the BOM at the beginning of the text overrides the byte-order 5780** specified by the interface procedure. ^So, for example, if 5781** sqlite3_result_text16le() is invoked with text that begins 5782** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the 5783** first two bytes of input are skipped and the remaining input 5784** is interpreted as UTF16BE text. 5785** 5786** ^For UTF16 input text to the sqlite3_result_text16(), 5787** sqlite3_result_text16be(), sqlite3_result_text16le(), and 5788** sqlite3_result_text64() routines, if the text contains invalid 5789** UTF16 characters, the invalid characters might be converted 5790** into the unicode replacement character, U+FFFD. 5791** 5792** ^The sqlite3_result_value() interface sets the result of 5793** the application-defined function to be a copy of the 5794** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5795** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5796** so that the [sqlite3_value] specified in the parameter may change or 5797** be deallocated after sqlite3_result_value() returns without harm. 5798** ^A [protected sqlite3_value] object may always be used where an 5799** [unprotected sqlite3_value] object is required, so either 5800** kind of [sqlite3_value] object can be used with this interface. 5801** 5802** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5803** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5804** also associates the host-language pointer P or type T with that 5805** NULL value such that the pointer can be retrieved within an 5806** [application-defined SQL function] using [sqlite3_value_pointer()]. 5807** ^If the D parameter is not NULL, then it is a pointer to a destructor 5808** for the P parameter. ^SQLite invokes D with P as its only argument 5809** when SQLite is finished with P. The T parameter should be a static 5810** string and preferably a string literal. The sqlite3_result_pointer() 5811** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5812** 5813** If these routines are called from within the different thread 5814** than the one containing the application-defined function that received 5815** the [sqlite3_context] pointer, the results are undefined. 5816*/ 5817void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5818void sqlite3_result_blob64(sqlite3_context*,const void*, 5819 sqlite3_uint64,void(*)(void*)); 5820void sqlite3_result_double(sqlite3_context*, double); 5821void sqlite3_result_error(sqlite3_context*, const char*, int); 5822void sqlite3_result_error16(sqlite3_context*, const void*, int); 5823void sqlite3_result_error_toobig(sqlite3_context*); 5824void sqlite3_result_error_nomem(sqlite3_context*); 5825void sqlite3_result_error_code(sqlite3_context*, int); 5826void sqlite3_result_int(sqlite3_context*, int); 5827void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5828void sqlite3_result_null(sqlite3_context*); 5829void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5830void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5831 void(*)(void*), unsigned char encoding); 5832void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5833void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5834void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5835void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5836void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5837void sqlite3_result_zeroblob(sqlite3_context*, int n); 5838int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5839 5840 5841/* 5842** CAPI3REF: Setting The Subtype Of An SQL Function 5843** METHOD: sqlite3_context 5844** 5845** The sqlite3_result_subtype(C,T) function causes the subtype of 5846** the result from the [application-defined SQL function] with 5847** [sqlite3_context] C to be the value T. Only the lower 8 bits 5848** of the subtype T are preserved in current versions of SQLite; 5849** higher order bits are discarded. 5850** The number of subtype bytes preserved by SQLite might increase 5851** in future releases of SQLite. 5852*/ 5853void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5854 5855/* 5856** CAPI3REF: Define New Collating Sequences 5857** METHOD: sqlite3 5858** 5859** ^These functions add, remove, or modify a [collation] associated 5860** with the [database connection] specified as the first argument. 5861** 5862** ^The name of the collation is a UTF-8 string 5863** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5864** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5865** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5866** considered to be the same name. 5867** 5868** ^(The third argument (eTextRep) must be one of the constants: 5869** <ul> 5870** <li> [SQLITE_UTF8], 5871** <li> [SQLITE_UTF16LE], 5872** <li> [SQLITE_UTF16BE], 5873** <li> [SQLITE_UTF16], or 5874** <li> [SQLITE_UTF16_ALIGNED]. 5875** </ul>)^ 5876** ^The eTextRep argument determines the encoding of strings passed 5877** to the collating function callback, xCompare. 5878** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5879** force strings to be UTF16 with native byte order. 5880** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5881** on an even byte address. 5882** 5883** ^The fourth argument, pArg, is an application data pointer that is passed 5884** through as the first argument to the collating function callback. 5885** 5886** ^The fifth argument, xCompare, is a pointer to the collating function. 5887** ^Multiple collating functions can be registered using the same name but 5888** with different eTextRep parameters and SQLite will use whichever 5889** function requires the least amount of data transformation. 5890** ^If the xCompare argument is NULL then the collating function is 5891** deleted. ^When all collating functions having the same name are deleted, 5892** that collation is no longer usable. 5893** 5894** ^The collating function callback is invoked with a copy of the pArg 5895** application data pointer and with two strings in the encoding specified 5896** by the eTextRep argument. The two integer parameters to the collating 5897** function callback are the length of the two strings, in bytes. The collating 5898** function must return an integer that is negative, zero, or positive 5899** if the first string is less than, equal to, or greater than the second, 5900** respectively. A collating function must always return the same answer 5901** given the same inputs. If two or more collating functions are registered 5902** to the same collation name (using different eTextRep values) then all 5903** must give an equivalent answer when invoked with equivalent strings. 5904** The collating function must obey the following properties for all 5905** strings A, B, and C: 5906** 5907** <ol> 5908** <li> If A==B then B==A. 5909** <li> If A==B and B==C then A==C. 5910** <li> If A<B THEN B>A. 5911** <li> If A<B and B<C then A<C. 5912** </ol> 5913** 5914** If a collating function fails any of the above constraints and that 5915** collating function is registered and used, then the behavior of SQLite 5916** is undefined. 5917** 5918** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5919** with the addition that the xDestroy callback is invoked on pArg when 5920** the collating function is deleted. 5921** ^Collating functions are deleted when they are overridden by later 5922** calls to the collation creation functions or when the 5923** [database connection] is closed using [sqlite3_close()]. 5924** 5925** ^The xDestroy callback is <u>not</u> called if the 5926** sqlite3_create_collation_v2() function fails. Applications that invoke 5927** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5928** check the return code and dispose of the application data pointer 5929** themselves rather than expecting SQLite to deal with it for them. 5930** This is different from every other SQLite interface. The inconsistency 5931** is unfortunate but cannot be changed without breaking backwards 5932** compatibility. 5933** 5934** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5935*/ 5936int sqlite3_create_collation( 5937 sqlite3*, 5938 const char *zName, 5939 int eTextRep, 5940 void *pArg, 5941 int(*xCompare)(void*,int,const void*,int,const void*) 5942); 5943int sqlite3_create_collation_v2( 5944 sqlite3*, 5945 const char *zName, 5946 int eTextRep, 5947 void *pArg, 5948 int(*xCompare)(void*,int,const void*,int,const void*), 5949 void(*xDestroy)(void*) 5950); 5951int sqlite3_create_collation16( 5952 sqlite3*, 5953 const void *zName, 5954 int eTextRep, 5955 void *pArg, 5956 int(*xCompare)(void*,int,const void*,int,const void*) 5957); 5958 5959/* 5960** CAPI3REF: Collation Needed Callbacks 5961** METHOD: sqlite3 5962** 5963** ^To avoid having to register all collation sequences before a database 5964** can be used, a single callback function may be registered with the 5965** [database connection] to be invoked whenever an undefined collation 5966** sequence is required. 5967** 5968** ^If the function is registered using the sqlite3_collation_needed() API, 5969** then it is passed the names of undefined collation sequences as strings 5970** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5971** the names are passed as UTF-16 in machine native byte order. 5972** ^A call to either function replaces the existing collation-needed callback. 5973** 5974** ^(When the callback is invoked, the first argument passed is a copy 5975** of the second argument to sqlite3_collation_needed() or 5976** sqlite3_collation_needed16(). The second argument is the database 5977** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5978** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5979** sequence function required. The fourth parameter is the name of the 5980** required collation sequence.)^ 5981** 5982** The callback function should register the desired collation using 5983** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5984** [sqlite3_create_collation_v2()]. 5985*/ 5986int sqlite3_collation_needed( 5987 sqlite3*, 5988 void*, 5989 void(*)(void*,sqlite3*,int eTextRep,const char*) 5990); 5991int sqlite3_collation_needed16( 5992 sqlite3*, 5993 void*, 5994 void(*)(void*,sqlite3*,int eTextRep,const void*) 5995); 5996 5997#ifdef SQLITE_ENABLE_CEROD 5998/* 5999** Specify the activation key for a CEROD database. Unless 6000** activated, none of the CEROD routines will work. 6001*/ 6002void sqlite3_activate_cerod( 6003 const char *zPassPhrase /* Activation phrase */ 6004); 6005#endif 6006 6007/* 6008** CAPI3REF: Suspend Execution For A Short Time 6009** 6010** The sqlite3_sleep() function causes the current thread to suspend execution 6011** for at least a number of milliseconds specified in its parameter. 6012** 6013** If the operating system does not support sleep requests with 6014** millisecond time resolution, then the time will be rounded up to 6015** the nearest second. The number of milliseconds of sleep actually 6016** requested from the operating system is returned. 6017** 6018** ^SQLite implements this interface by calling the xSleep() 6019** method of the default [sqlite3_vfs] object. If the xSleep() method 6020** of the default VFS is not implemented correctly, or not implemented at 6021** all, then the behavior of sqlite3_sleep() may deviate from the description 6022** in the previous paragraphs. 6023*/ 6024int sqlite3_sleep(int); 6025 6026/* 6027** CAPI3REF: Name Of The Folder Holding Temporary Files 6028** 6029** ^(If this global variable is made to point to a string which is 6030** the name of a folder (a.k.a. directory), then all temporary files 6031** created by SQLite when using a built-in [sqlite3_vfs | VFS] 6032** will be placed in that directory.)^ ^If this variable 6033** is a NULL pointer, then SQLite performs a search for an appropriate 6034** temporary file directory. 6035** 6036** Applications are strongly discouraged from using this global variable. 6037** It is required to set a temporary folder on Windows Runtime (WinRT). 6038** But for all other platforms, it is highly recommended that applications 6039** neither read nor write this variable. This global variable is a relic 6040** that exists for backwards compatibility of legacy applications and should 6041** be avoided in new projects. 6042** 6043** It is not safe to read or modify this variable in more than one 6044** thread at a time. It is not safe to read or modify this variable 6045** if a [database connection] is being used at the same time in a separate 6046** thread. 6047** It is intended that this variable be set once 6048** as part of process initialization and before any SQLite interface 6049** routines have been called and that this variable remain unchanged 6050** thereafter. 6051** 6052** ^The [temp_store_directory pragma] may modify this variable and cause 6053** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6054** the [temp_store_directory pragma] always assumes that any string 6055** that this variable points to is held in memory obtained from 6056** [sqlite3_malloc] and the pragma may attempt to free that memory 6057** using [sqlite3_free]. 6058** Hence, if this variable is modified directly, either it should be 6059** made NULL or made to point to memory obtained from [sqlite3_malloc] 6060** or else the use of the [temp_store_directory pragma] should be avoided. 6061** Except when requested by the [temp_store_directory pragma], SQLite 6062** does not free the memory that sqlite3_temp_directory points to. If 6063** the application wants that memory to be freed, it must do 6064** so itself, taking care to only do so after all [database connection] 6065** objects have been destroyed. 6066** 6067** <b>Note to Windows Runtime users:</b> The temporary directory must be set 6068** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 6069** features that require the use of temporary files may fail. Here is an 6070** example of how to do this using C++ with the Windows Runtime: 6071** 6072** <blockquote><pre> 6073** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 6074** TemporaryFolder->Path->Data(); 6075** char zPathBuf[MAX_PATH + 1]; 6076** memset(zPathBuf, 0, sizeof(zPathBuf)); 6077** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 6078** NULL, NULL); 6079** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 6080** </pre></blockquote> 6081*/ 6082SQLITE_EXTERN char *sqlite3_temp_directory; 6083 6084/* 6085** CAPI3REF: Name Of The Folder Holding Database Files 6086** 6087** ^(If this global variable is made to point to a string which is 6088** the name of a folder (a.k.a. directory), then all database files 6089** specified with a relative pathname and created or accessed by 6090** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 6091** to be relative to that directory.)^ ^If this variable is a NULL 6092** pointer, then SQLite assumes that all database files specified 6093** with a relative pathname are relative to the current directory 6094** for the process. Only the windows VFS makes use of this global 6095** variable; it is ignored by the unix VFS. 6096** 6097** Changing the value of this variable while a database connection is 6098** open can result in a corrupt database. 6099** 6100** It is not safe to read or modify this variable in more than one 6101** thread at a time. It is not safe to read or modify this variable 6102** if a [database connection] is being used at the same time in a separate 6103** thread. 6104** It is intended that this variable be set once 6105** as part of process initialization and before any SQLite interface 6106** routines have been called and that this variable remain unchanged 6107** thereafter. 6108** 6109** ^The [data_store_directory pragma] may modify this variable and cause 6110** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6111** the [data_store_directory pragma] always assumes that any string 6112** that this variable points to is held in memory obtained from 6113** [sqlite3_malloc] and the pragma may attempt to free that memory 6114** using [sqlite3_free]. 6115** Hence, if this variable is modified directly, either it should be 6116** made NULL or made to point to memory obtained from [sqlite3_malloc] 6117** or else the use of the [data_store_directory pragma] should be avoided. 6118*/ 6119SQLITE_EXTERN char *sqlite3_data_directory; 6120 6121/* 6122** CAPI3REF: Win32 Specific Interface 6123** 6124** These interfaces are available only on Windows. The 6125** [sqlite3_win32_set_directory] interface is used to set the value associated 6126** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to 6127** zValue, depending on the value of the type parameter. The zValue parameter 6128** should be NULL to cause the previous value to be freed via [sqlite3_free]; 6129** a non-NULL value will be copied into memory obtained from [sqlite3_malloc] 6130** prior to being used. The [sqlite3_win32_set_directory] interface returns 6131** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported, 6132** or [SQLITE_NOMEM] if memory could not be allocated. The value of the 6133** [sqlite3_data_directory] variable is intended to act as a replacement for 6134** the current directory on the sub-platforms of Win32 where that concept is 6135** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and 6136** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the 6137** sqlite3_win32_set_directory interface except the string parameter must be 6138** UTF-8 or UTF-16, respectively. 6139*/ 6140int sqlite3_win32_set_directory( 6141 unsigned long type, /* Identifier for directory being set or reset */ 6142 void *zValue /* New value for directory being set or reset */ 6143); 6144int sqlite3_win32_set_directory8(unsigned long type, const char *zValue); 6145int sqlite3_win32_set_directory16(unsigned long type, const void *zValue); 6146 6147/* 6148** CAPI3REF: Win32 Directory Types 6149** 6150** These macros are only available on Windows. They define the allowed values 6151** for the type argument to the [sqlite3_win32_set_directory] interface. 6152*/ 6153#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1 6154#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2 6155 6156/* 6157** CAPI3REF: Test For Auto-Commit Mode 6158** KEYWORDS: {autocommit mode} 6159** METHOD: sqlite3 6160** 6161** ^The sqlite3_get_autocommit() interface returns non-zero or 6162** zero if the given database connection is or is not in autocommit mode, 6163** respectively. ^Autocommit mode is on by default. 6164** ^Autocommit mode is disabled by a [BEGIN] statement. 6165** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 6166** 6167** If certain kinds of errors occur on a statement within a multi-statement 6168** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 6169** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 6170** transaction might be rolled back automatically. The only way to 6171** find out whether SQLite automatically rolled back the transaction after 6172** an error is to use this function. 6173** 6174** If another thread changes the autocommit status of the database 6175** connection while this routine is running, then the return value 6176** is undefined. 6177*/ 6178int sqlite3_get_autocommit(sqlite3*); 6179 6180/* 6181** CAPI3REF: Find The Database Handle Of A Prepared Statement 6182** METHOD: sqlite3_stmt 6183** 6184** ^The sqlite3_db_handle interface returns the [database connection] handle 6185** to which a [prepared statement] belongs. ^The [database connection] 6186** returned by sqlite3_db_handle is the same [database connection] 6187** that was the first argument 6188** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 6189** create the statement in the first place. 6190*/ 6191sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 6192 6193/* 6194** CAPI3REF: Return The Filename For A Database Connection 6195** METHOD: sqlite3 6196** 6197** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename 6198** associated with database N of connection D. 6199** ^If there is no attached database N on the database 6200** connection D, or if database N is a temporary or in-memory database, then 6201** this function will return either a NULL pointer or an empty string. 6202** 6203** ^The string value returned by this routine is owned and managed by 6204** the database connection. ^The value will be valid until the database N 6205** is [DETACH]-ed or until the database connection closes. 6206** 6207** ^The filename returned by this function is the output of the 6208** xFullPathname method of the [VFS]. ^In other words, the filename 6209** will be an absolute pathname, even if the filename used 6210** to open the database originally was a URI or relative pathname. 6211** 6212** If the filename pointer returned by this routine is not NULL, then it 6213** can be used as the filename input parameter to these routines: 6214** <ul> 6215** <li> [sqlite3_uri_parameter()] 6216** <li> [sqlite3_uri_boolean()] 6217** <li> [sqlite3_uri_int64()] 6218** <li> [sqlite3_filename_database()] 6219** <li> [sqlite3_filename_journal()] 6220** <li> [sqlite3_filename_wal()] 6221** </ul> 6222*/ 6223const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 6224 6225/* 6226** CAPI3REF: Determine if a database is read-only 6227** METHOD: sqlite3 6228** 6229** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 6230** of connection D is read-only, 0 if it is read/write, or -1 if N is not 6231** the name of a database on connection D. 6232*/ 6233int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 6234 6235/* 6236** CAPI3REF: Determine the transaction state of a database 6237** METHOD: sqlite3 6238** 6239** ^The sqlite3_txn_state(D,S) interface returns the current 6240** [transaction state] of schema S in database connection D. ^If S is NULL, 6241** then the highest transaction state of any schema on database connection D 6242** is returned. Transaction states are (in order of lowest to highest): 6243** <ol> 6244** <li value="0"> SQLITE_TXN_NONE 6245** <li value="1"> SQLITE_TXN_READ 6246** <li value="2"> SQLITE_TXN_WRITE 6247** </ol> 6248** ^If the S argument to sqlite3_txn_state(D,S) is not the name of 6249** a valid schema, then -1 is returned. 6250*/ 6251int sqlite3_txn_state(sqlite3*,const char *zSchema); 6252 6253/* 6254** CAPI3REF: Allowed return values from [sqlite3_txn_state()] 6255** KEYWORDS: {transaction state} 6256** 6257** These constants define the current transaction state of a database file. 6258** ^The [sqlite3_txn_state(D,S)] interface returns one of these 6259** constants in order to describe the transaction state of schema S 6260** in [database connection] D. 6261** 6262** <dl> 6263** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt> 6264** <dd>The SQLITE_TXN_NONE state means that no transaction is currently 6265** pending.</dd> 6266** 6267** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt> 6268** <dd>The SQLITE_TXN_READ state means that the database is currently 6269** in a read transaction. Content has been read from the database file 6270** but nothing in the database file has changed. The transaction state 6271** will advanced to SQLITE_TXN_WRITE if any changes occur and there are 6272** no other conflicting concurrent write transactions. The transaction 6273** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or 6274** [COMMIT].</dd> 6275** 6276** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt> 6277** <dd>The SQLITE_TXN_WRITE state means that the database is currently 6278** in a write transaction. Content has been written to the database file 6279** but has not yet committed. The transaction state will change to 6280** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd> 6281*/ 6282#define SQLITE_TXN_NONE 0 6283#define SQLITE_TXN_READ 1 6284#define SQLITE_TXN_WRITE 2 6285 6286/* 6287** CAPI3REF: Find the next prepared statement 6288** METHOD: sqlite3 6289** 6290** ^This interface returns a pointer to the next [prepared statement] after 6291** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 6292** then this interface returns a pointer to the first prepared statement 6293** associated with the database connection pDb. ^If no prepared statement 6294** satisfies the conditions of this routine, it returns NULL. 6295** 6296** The [database connection] pointer D in a call to 6297** [sqlite3_next_stmt(D,S)] must refer to an open database 6298** connection and in particular must not be a NULL pointer. 6299*/ 6300sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 6301 6302/* 6303** CAPI3REF: Commit And Rollback Notification Callbacks 6304** METHOD: sqlite3 6305** 6306** ^The sqlite3_commit_hook() interface registers a callback 6307** function to be invoked whenever a transaction is [COMMIT | committed]. 6308** ^Any callback set by a previous call to sqlite3_commit_hook() 6309** for the same database connection is overridden. 6310** ^The sqlite3_rollback_hook() interface registers a callback 6311** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 6312** ^Any callback set by a previous call to sqlite3_rollback_hook() 6313** for the same database connection is overridden. 6314** ^The pArg argument is passed through to the callback. 6315** ^If the callback on a commit hook function returns non-zero, 6316** then the commit is converted into a rollback. 6317** 6318** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 6319** return the P argument from the previous call of the same function 6320** on the same [database connection] D, or NULL for 6321** the first call for each function on D. 6322** 6323** The commit and rollback hook callbacks are not reentrant. 6324** The callback implementation must not do anything that will modify 6325** the database connection that invoked the callback. Any actions 6326** to modify the database connection must be deferred until after the 6327** completion of the [sqlite3_step()] call that triggered the commit 6328** or rollback hook in the first place. 6329** Note that running any other SQL statements, including SELECT statements, 6330** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 6331** the database connections for the meaning of "modify" in this paragraph. 6332** 6333** ^Registering a NULL function disables the callback. 6334** 6335** ^When the commit hook callback routine returns zero, the [COMMIT] 6336** operation is allowed to continue normally. ^If the commit hook 6337** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 6338** ^The rollback hook is invoked on a rollback that results from a commit 6339** hook returning non-zero, just as it would be with any other rollback. 6340** 6341** ^For the purposes of this API, a transaction is said to have been 6342** rolled back if an explicit "ROLLBACK" statement is executed, or 6343** an error or constraint causes an implicit rollback to occur. 6344** ^The rollback callback is not invoked if a transaction is 6345** automatically rolled back because the database connection is closed. 6346** 6347** See also the [sqlite3_update_hook()] interface. 6348*/ 6349void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 6350void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 6351 6352/* 6353** CAPI3REF: Data Change Notification Callbacks 6354** METHOD: sqlite3 6355** 6356** ^The sqlite3_update_hook() interface registers a callback function 6357** with the [database connection] identified by the first argument 6358** to be invoked whenever a row is updated, inserted or deleted in 6359** a [rowid table]. 6360** ^Any callback set by a previous call to this function 6361** for the same database connection is overridden. 6362** 6363** ^The second argument is a pointer to the function to invoke when a 6364** row is updated, inserted or deleted in a rowid table. 6365** ^The first argument to the callback is a copy of the third argument 6366** to sqlite3_update_hook(). 6367** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 6368** or [SQLITE_UPDATE], depending on the operation that caused the callback 6369** to be invoked. 6370** ^The third and fourth arguments to the callback contain pointers to the 6371** database and table name containing the affected row. 6372** ^The final callback parameter is the [rowid] of the row. 6373** ^In the case of an update, this is the [rowid] after the update takes place. 6374** 6375** ^(The update hook is not invoked when internal system tables are 6376** modified (i.e. sqlite_sequence).)^ 6377** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 6378** 6379** ^In the current implementation, the update hook 6380** is not invoked when conflicting rows are deleted because of an 6381** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 6382** invoked when rows are deleted using the [truncate optimization]. 6383** The exceptions defined in this paragraph might change in a future 6384** release of SQLite. 6385** 6386** The update hook implementation must not do anything that will modify 6387** the database connection that invoked the update hook. Any actions 6388** to modify the database connection must be deferred until after the 6389** completion of the [sqlite3_step()] call that triggered the update hook. 6390** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 6391** database connections for the meaning of "modify" in this paragraph. 6392** 6393** ^The sqlite3_update_hook(D,C,P) function 6394** returns the P argument from the previous call 6395** on the same [database connection] D, or NULL for 6396** the first call on D. 6397** 6398** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 6399** and [sqlite3_preupdate_hook()] interfaces. 6400*/ 6401void *sqlite3_update_hook( 6402 sqlite3*, 6403 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 6404 void* 6405); 6406 6407/* 6408** CAPI3REF: Enable Or Disable Shared Pager Cache 6409** 6410** ^(This routine enables or disables the sharing of the database cache 6411** and schema data structures between [database connection | connections] 6412** to the same database. Sharing is enabled if the argument is true 6413** and disabled if the argument is false.)^ 6414** 6415** ^Cache sharing is enabled and disabled for an entire process. 6416** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 6417** In prior versions of SQLite, 6418** sharing was enabled or disabled for each thread separately. 6419** 6420** ^(The cache sharing mode set by this interface effects all subsequent 6421** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 6422** Existing database connections continue to use the sharing mode 6423** that was in effect at the time they were opened.)^ 6424** 6425** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 6426** successfully. An [error code] is returned otherwise.)^ 6427** 6428** ^Shared cache is disabled by default. It is recommended that it stay 6429** that way. In other words, do not use this routine. This interface 6430** continues to be provided for historical compatibility, but its use is 6431** discouraged. Any use of shared cache is discouraged. If shared cache 6432** must be used, it is recommended that shared cache only be enabled for 6433** individual database connections using the [sqlite3_open_v2()] interface 6434** with the [SQLITE_OPEN_SHAREDCACHE] flag. 6435** 6436** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 6437** and will always return SQLITE_MISUSE. On those systems, 6438** shared cache mode should be enabled per-database connection via 6439** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 6440** 6441** This interface is threadsafe on processors where writing a 6442** 32-bit integer is atomic. 6443** 6444** See Also: [SQLite Shared-Cache Mode] 6445*/ 6446int sqlite3_enable_shared_cache(int); 6447 6448/* 6449** CAPI3REF: Attempt To Free Heap Memory 6450** 6451** ^The sqlite3_release_memory() interface attempts to free N bytes 6452** of heap memory by deallocating non-essential memory allocations 6453** held by the database library. Memory used to cache database 6454** pages to improve performance is an example of non-essential memory. 6455** ^sqlite3_release_memory() returns the number of bytes actually freed, 6456** which might be more or less than the amount requested. 6457** ^The sqlite3_release_memory() routine is a no-op returning zero 6458** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 6459** 6460** See also: [sqlite3_db_release_memory()] 6461*/ 6462int sqlite3_release_memory(int); 6463 6464/* 6465** CAPI3REF: Free Memory Used By A Database Connection 6466** METHOD: sqlite3 6467** 6468** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 6469** memory as possible from database connection D. Unlike the 6470** [sqlite3_release_memory()] interface, this interface is in effect even 6471** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 6472** omitted. 6473** 6474** See also: [sqlite3_release_memory()] 6475*/ 6476int sqlite3_db_release_memory(sqlite3*); 6477 6478/* 6479** CAPI3REF: Impose A Limit On Heap Size 6480** 6481** These interfaces impose limits on the amount of heap memory that will be 6482** by all database connections within a single process. 6483** 6484** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 6485** soft limit on the amount of heap memory that may be allocated by SQLite. 6486** ^SQLite strives to keep heap memory utilization below the soft heap 6487** limit by reducing the number of pages held in the page cache 6488** as heap memory usages approaches the limit. 6489** ^The soft heap limit is "soft" because even though SQLite strives to stay 6490** below the limit, it will exceed the limit rather than generate 6491** an [SQLITE_NOMEM] error. In other words, the soft heap limit 6492** is advisory only. 6493** 6494** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of 6495** N bytes on the amount of memory that will be allocated. ^The 6496** sqlite3_hard_heap_limit64(N) interface is similar to 6497** sqlite3_soft_heap_limit64(N) except that memory allocations will fail 6498** when the hard heap limit is reached. 6499** 6500** ^The return value from both sqlite3_soft_heap_limit64() and 6501** sqlite3_hard_heap_limit64() is the size of 6502** the heap limit prior to the call, or negative in the case of an 6503** error. ^If the argument N is negative 6504** then no change is made to the heap limit. Hence, the current 6505** size of heap limits can be determined by invoking 6506** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1). 6507** 6508** ^Setting the heap limits to zero disables the heap limiter mechanism. 6509** 6510** ^The soft heap limit may not be greater than the hard heap limit. 6511** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N) 6512** is invoked with a value of N that is greater than the hard heap limit, 6513** the the soft heap limit is set to the value of the hard heap limit. 6514** ^The soft heap limit is automatically enabled whenever the hard heap 6515** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and 6516** the soft heap limit is outside the range of 1..N, then the soft heap 6517** limit is set to N. ^Invoking sqlite3_soft_heap_limit64(0) when the 6518** hard heap limit is enabled makes the soft heap limit equal to the 6519** hard heap limit. 6520** 6521** The memory allocation limits can also be adjusted using 6522** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit]. 6523** 6524** ^(The heap limits are not enforced in the current implementation 6525** if one or more of following conditions are true: 6526** 6527** <ul> 6528** <li> The limit value is set to zero. 6529** <li> Memory accounting is disabled using a combination of the 6530** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 6531** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 6532** <li> An alternative page cache implementation is specified using 6533** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 6534** <li> The page cache allocates from its own memory pool supplied 6535** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 6536** from the heap. 6537** </ul>)^ 6538** 6539** The circumstances under which SQLite will enforce the heap limits may 6540** changes in future releases of SQLite. 6541*/ 6542sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 6543sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N); 6544 6545/* 6546** CAPI3REF: Deprecated Soft Heap Limit Interface 6547** DEPRECATED 6548** 6549** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 6550** interface. This routine is provided for historical compatibility 6551** only. All new applications should use the 6552** [sqlite3_soft_heap_limit64()] interface rather than this one. 6553*/ 6554SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 6555 6556 6557/* 6558** CAPI3REF: Extract Metadata About A Column Of A Table 6559** METHOD: sqlite3 6560** 6561** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 6562** information about column C of table T in database D 6563** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 6564** interface returns SQLITE_OK and fills in the non-NULL pointers in 6565** the final five arguments with appropriate values if the specified 6566** column exists. ^The sqlite3_table_column_metadata() interface returns 6567** SQLITE_ERROR if the specified column does not exist. 6568** ^If the column-name parameter to sqlite3_table_column_metadata() is a 6569** NULL pointer, then this routine simply checks for the existence of the 6570** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 6571** does not. If the table name parameter T in a call to 6572** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 6573** undefined behavior. 6574** 6575** ^The column is identified by the second, third and fourth parameters to 6576** this function. ^(The second parameter is either the name of the database 6577** (i.e. "main", "temp", or an attached database) containing the specified 6578** table or NULL.)^ ^If it is NULL, then all attached databases are searched 6579** for the table using the same algorithm used by the database engine to 6580** resolve unqualified table references. 6581** 6582** ^The third and fourth parameters to this function are the table and column 6583** name of the desired column, respectively. 6584** 6585** ^Metadata is returned by writing to the memory locations passed as the 5th 6586** and subsequent parameters to this function. ^Any of these arguments may be 6587** NULL, in which case the corresponding element of metadata is omitted. 6588** 6589** ^(<blockquote> 6590** <table border="1"> 6591** <tr><th> Parameter <th> Output<br>Type <th> Description 6592** 6593** <tr><td> 5th <td> const char* <td> Data type 6594** <tr><td> 6th <td> const char* <td> Name of default collation sequence 6595** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 6596** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 6597** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 6598** </table> 6599** </blockquote>)^ 6600** 6601** ^The memory pointed to by the character pointers returned for the 6602** declaration type and collation sequence is valid until the next 6603** call to any SQLite API function. 6604** 6605** ^If the specified table is actually a view, an [error code] is returned. 6606** 6607** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 6608** is not a [WITHOUT ROWID] table and an 6609** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 6610** parameters are set for the explicitly declared column. ^(If there is no 6611** [INTEGER PRIMARY KEY] column, then the outputs 6612** for the [rowid] are set as follows: 6613** 6614** <pre> 6615** data type: "INTEGER" 6616** collation sequence: "BINARY" 6617** not null: 0 6618** primary key: 1 6619** auto increment: 0 6620** </pre>)^ 6621** 6622** ^This function causes all database schemas to be read from disk and 6623** parsed, if that has not already been done, and returns an error if 6624** any errors are encountered while loading the schema. 6625*/ 6626int sqlite3_table_column_metadata( 6627 sqlite3 *db, /* Connection handle */ 6628 const char *zDbName, /* Database name or NULL */ 6629 const char *zTableName, /* Table name */ 6630 const char *zColumnName, /* Column name */ 6631 char const **pzDataType, /* OUTPUT: Declared data type */ 6632 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 6633 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 6634 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 6635 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 6636); 6637 6638/* 6639** CAPI3REF: Load An Extension 6640** METHOD: sqlite3 6641** 6642** ^This interface loads an SQLite extension library from the named file. 6643** 6644** ^The sqlite3_load_extension() interface attempts to load an 6645** [SQLite extension] library contained in the file zFile. If 6646** the file cannot be loaded directly, attempts are made to load 6647** with various operating-system specific extensions added. 6648** So for example, if "samplelib" cannot be loaded, then names like 6649** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 6650** be tried also. 6651** 6652** ^The entry point is zProc. 6653** ^(zProc may be 0, in which case SQLite will try to come up with an 6654** entry point name on its own. It first tries "sqlite3_extension_init". 6655** If that does not work, it constructs a name "sqlite3_X_init" where the 6656** X is consists of the lower-case equivalent of all ASCII alphabetic 6657** characters in the filename from the last "/" to the first following 6658** "." and omitting any initial "lib".)^ 6659** ^The sqlite3_load_extension() interface returns 6660** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 6661** ^If an error occurs and pzErrMsg is not 0, then the 6662** [sqlite3_load_extension()] interface shall attempt to 6663** fill *pzErrMsg with error message text stored in memory 6664** obtained from [sqlite3_malloc()]. The calling function 6665** should free this memory by calling [sqlite3_free()]. 6666** 6667** ^Extension loading must be enabled using 6668** [sqlite3_enable_load_extension()] or 6669** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 6670** prior to calling this API, 6671** otherwise an error will be returned. 6672** 6673** <b>Security warning:</b> It is recommended that the 6674** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 6675** interface. The use of the [sqlite3_enable_load_extension()] interface 6676** should be avoided. This will keep the SQL function [load_extension()] 6677** disabled and prevent SQL injections from giving attackers 6678** access to extension loading capabilities. 6679** 6680** See also the [load_extension() SQL function]. 6681*/ 6682int sqlite3_load_extension( 6683 sqlite3 *db, /* Load the extension into this database connection */ 6684 const char *zFile, /* Name of the shared library containing extension */ 6685 const char *zProc, /* Entry point. Derived from zFile if 0 */ 6686 char **pzErrMsg /* Put error message here if not 0 */ 6687); 6688 6689/* 6690** CAPI3REF: Enable Or Disable Extension Loading 6691** METHOD: sqlite3 6692** 6693** ^So as not to open security holes in older applications that are 6694** unprepared to deal with [extension loading], and as a means of disabling 6695** [extension loading] while evaluating user-entered SQL, the following API 6696** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 6697** 6698** ^Extension loading is off by default. 6699** ^Call the sqlite3_enable_load_extension() routine with onoff==1 6700** to turn extension loading on and call it with onoff==0 to turn 6701** it back off again. 6702** 6703** ^This interface enables or disables both the C-API 6704** [sqlite3_load_extension()] and the SQL function [load_extension()]. 6705** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 6706** to enable or disable only the C-API.)^ 6707** 6708** <b>Security warning:</b> It is recommended that extension loading 6709** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 6710** rather than this interface, so the [load_extension()] SQL function 6711** remains disabled. This will prevent SQL injections from giving attackers 6712** access to extension loading capabilities. 6713*/ 6714int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6715 6716/* 6717** CAPI3REF: Automatically Load Statically Linked Extensions 6718** 6719** ^This interface causes the xEntryPoint() function to be invoked for 6720** each new [database connection] that is created. The idea here is that 6721** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6722** that is to be automatically loaded into all new database connections. 6723** 6724** ^(Even though the function prototype shows that xEntryPoint() takes 6725** no arguments and returns void, SQLite invokes xEntryPoint() with three 6726** arguments and expects an integer result as if the signature of the 6727** entry point where as follows: 6728** 6729** <blockquote><pre> 6730** int xEntryPoint( 6731** sqlite3 *db, 6732** const char **pzErrMsg, 6733** const struct sqlite3_api_routines *pThunk 6734** ); 6735** </pre></blockquote>)^ 6736** 6737** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6738** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6739** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6740** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6741** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6742** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6743** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6744** 6745** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6746** on the list of automatic extensions is a harmless no-op. ^No entry point 6747** will be called more than once for each database connection that is opened. 6748** 6749** See also: [sqlite3_reset_auto_extension()] 6750** and [sqlite3_cancel_auto_extension()] 6751*/ 6752int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6753 6754/* 6755** CAPI3REF: Cancel Automatic Extension Loading 6756** 6757** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6758** initialization routine X that was registered using a prior call to 6759** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6760** routine returns 1 if initialization routine X was successfully 6761** unregistered and it returns 0 if X was not on the list of initialization 6762** routines. 6763*/ 6764int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6765 6766/* 6767** CAPI3REF: Reset Automatic Extension Loading 6768** 6769** ^This interface disables all automatic extensions previously 6770** registered using [sqlite3_auto_extension()]. 6771*/ 6772void sqlite3_reset_auto_extension(void); 6773 6774/* 6775** The interface to the virtual-table mechanism is currently considered 6776** to be experimental. The interface might change in incompatible ways. 6777** If this is a problem for you, do not use the interface at this time. 6778** 6779** When the virtual-table mechanism stabilizes, we will declare the 6780** interface fixed, support it indefinitely, and remove this comment. 6781*/ 6782 6783/* 6784** Structures used by the virtual table interface 6785*/ 6786typedef struct sqlite3_vtab sqlite3_vtab; 6787typedef struct sqlite3_index_info sqlite3_index_info; 6788typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6789typedef struct sqlite3_module sqlite3_module; 6790 6791/* 6792** CAPI3REF: Virtual Table Object 6793** KEYWORDS: sqlite3_module {virtual table module} 6794** 6795** This structure, sometimes called a "virtual table module", 6796** defines the implementation of a [virtual table]. 6797** This structure consists mostly of methods for the module. 6798** 6799** ^A virtual table module is created by filling in a persistent 6800** instance of this structure and passing a pointer to that instance 6801** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6802** ^The registration remains valid until it is replaced by a different 6803** module or until the [database connection] closes. The content 6804** of this structure must not change while it is registered with 6805** any database connection. 6806*/ 6807struct sqlite3_module { 6808 int iVersion; 6809 int (*xCreate)(sqlite3*, void *pAux, 6810 int argc, const char *const*argv, 6811 sqlite3_vtab **ppVTab, char**); 6812 int (*xConnect)(sqlite3*, void *pAux, 6813 int argc, const char *const*argv, 6814 sqlite3_vtab **ppVTab, char**); 6815 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6816 int (*xDisconnect)(sqlite3_vtab *pVTab); 6817 int (*xDestroy)(sqlite3_vtab *pVTab); 6818 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6819 int (*xClose)(sqlite3_vtab_cursor*); 6820 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6821 int argc, sqlite3_value **argv); 6822 int (*xNext)(sqlite3_vtab_cursor*); 6823 int (*xEof)(sqlite3_vtab_cursor*); 6824 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6825 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6826 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6827 int (*xBegin)(sqlite3_vtab *pVTab); 6828 int (*xSync)(sqlite3_vtab *pVTab); 6829 int (*xCommit)(sqlite3_vtab *pVTab); 6830 int (*xRollback)(sqlite3_vtab *pVTab); 6831 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6832 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6833 void **ppArg); 6834 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6835 /* The methods above are in version 1 of the sqlite_module object. Those 6836 ** below are for version 2 and greater. */ 6837 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6838 int (*xRelease)(sqlite3_vtab *pVTab, int); 6839 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6840 /* The methods above are in versions 1 and 2 of the sqlite_module object. 6841 ** Those below are for version 3 and greater. */ 6842 int (*xShadowName)(const char*); 6843}; 6844 6845/* 6846** CAPI3REF: Virtual Table Indexing Information 6847** KEYWORDS: sqlite3_index_info 6848** 6849** The sqlite3_index_info structure and its substructures is used as part 6850** of the [virtual table] interface to 6851** pass information into and receive the reply from the [xBestIndex] 6852** method of a [virtual table module]. The fields under **Inputs** are the 6853** inputs to xBestIndex and are read-only. xBestIndex inserts its 6854** results into the **Outputs** fields. 6855** 6856** ^(The aConstraint[] array records WHERE clause constraints of the form: 6857** 6858** <blockquote>column OP expr</blockquote> 6859** 6860** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6861** stored in aConstraint[].op using one of the 6862** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6863** ^(The index of the column is stored in 6864** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6865** expr on the right-hand side can be evaluated (and thus the constraint 6866** is usable) and false if it cannot.)^ 6867** 6868** ^The optimizer automatically inverts terms of the form "expr OP column" 6869** and makes other simplifications to the WHERE clause in an attempt to 6870** get as many WHERE clause terms into the form shown above as possible. 6871** ^The aConstraint[] array only reports WHERE clause terms that are 6872** relevant to the particular virtual table being queried. 6873** 6874** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6875** ^Each term of aOrderBy records a column of the ORDER BY clause. 6876** 6877** The colUsed field indicates which columns of the virtual table may be 6878** required by the current scan. Virtual table columns are numbered from 6879** zero in the order in which they appear within the CREATE TABLE statement 6880** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6881** the corresponding bit is set within the colUsed mask if the column may be 6882** required by SQLite. If the table has at least 64 columns and any column 6883** to the right of the first 63 is required, then bit 63 of colUsed is also 6884** set. In other words, column iCol may be required if the expression 6885** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6886** non-zero. 6887** 6888** The [xBestIndex] method must fill aConstraintUsage[] with information 6889** about what parameters to pass to xFilter. ^If argvIndex>0 then 6890** the right-hand side of the corresponding aConstraint[] is evaluated 6891** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6892** is true, then the constraint is assumed to be fully handled by the 6893** virtual table and might not be checked again by the byte code.)^ ^(The 6894** aConstraintUsage[].omit flag is an optimization hint. When the omit flag 6895** is left in its default setting of false, the constraint will always be 6896** checked separately in byte code. If the omit flag is change to true, then 6897** the constraint may or may not be checked in byte code. In other words, 6898** when the omit flag is true there is no guarantee that the constraint will 6899** not be checked again using byte code.)^ 6900** 6901** ^The idxNum and idxPtr values are recorded and passed into the 6902** [xFilter] method. 6903** ^[sqlite3_free()] is used to free idxPtr if and only if 6904** needToFreeIdxPtr is true. 6905** 6906** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6907** the correct order to satisfy the ORDER BY clause so that no separate 6908** sorting step is required. 6909** 6910** ^The estimatedCost value is an estimate of the cost of a particular 6911** strategy. A cost of N indicates that the cost of the strategy is similar 6912** to a linear scan of an SQLite table with N rows. A cost of log(N) 6913** indicates that the expense of the operation is similar to that of a 6914** binary search on a unique indexed field of an SQLite table with N rows. 6915** 6916** ^The estimatedRows value is an estimate of the number of rows that 6917** will be returned by the strategy. 6918** 6919** The xBestIndex method may optionally populate the idxFlags field with a 6920** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6921** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6922** assumes that the strategy may visit at most one row. 6923** 6924** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6925** SQLite also assumes that if a call to the xUpdate() method is made as 6926** part of the same statement to delete or update a virtual table row and the 6927** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6928** any database changes. In other words, if the xUpdate() returns 6929** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6930** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6931** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6932** the xUpdate method are automatically rolled back by SQLite. 6933** 6934** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6935** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6936** If a virtual table extension is 6937** used with an SQLite version earlier than 3.8.2, the results of attempting 6938** to read or write the estimatedRows field are undefined (but are likely 6939** to include crashing the application). The estimatedRows field should 6940** therefore only be used if [sqlite3_libversion_number()] returns a 6941** value greater than or equal to 3008002. Similarly, the idxFlags field 6942** was added for [version 3.9.0] ([dateof:3.9.0]). 6943** It may therefore only be used if 6944** sqlite3_libversion_number() returns a value greater than or equal to 6945** 3009000. 6946*/ 6947struct sqlite3_index_info { 6948 /* Inputs */ 6949 int nConstraint; /* Number of entries in aConstraint */ 6950 struct sqlite3_index_constraint { 6951 int iColumn; /* Column constrained. -1 for ROWID */ 6952 unsigned char op; /* Constraint operator */ 6953 unsigned char usable; /* True if this constraint is usable */ 6954 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6955 } *aConstraint; /* Table of WHERE clause constraints */ 6956 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6957 struct sqlite3_index_orderby { 6958 int iColumn; /* Column number */ 6959 unsigned char desc; /* True for DESC. False for ASC. */ 6960 } *aOrderBy; /* The ORDER BY clause */ 6961 /* Outputs */ 6962 struct sqlite3_index_constraint_usage { 6963 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6964 unsigned char omit; /* Do not code a test for this constraint */ 6965 } *aConstraintUsage; 6966 int idxNum; /* Number used to identify the index */ 6967 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6968 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6969 int orderByConsumed; /* True if output is already ordered */ 6970 double estimatedCost; /* Estimated cost of using this index */ 6971 /* Fields below are only available in SQLite 3.8.2 and later */ 6972 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6973 /* Fields below are only available in SQLite 3.9.0 and later */ 6974 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6975 /* Fields below are only available in SQLite 3.10.0 and later */ 6976 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6977}; 6978 6979/* 6980** CAPI3REF: Virtual Table Scan Flags 6981** 6982** Virtual table implementations are allowed to set the 6983** [sqlite3_index_info].idxFlags field to some combination of 6984** these bits. 6985*/ 6986#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6987 6988/* 6989** CAPI3REF: Virtual Table Constraint Operator Codes 6990** 6991** These macros define the allowed values for the 6992** [sqlite3_index_info].aConstraint[].op field. Each value represents 6993** an operator that is part of a constraint term in the wHERE clause of 6994** a query that uses a [virtual table]. 6995*/ 6996#define SQLITE_INDEX_CONSTRAINT_EQ 2 6997#define SQLITE_INDEX_CONSTRAINT_GT 4 6998#define SQLITE_INDEX_CONSTRAINT_LE 8 6999#define SQLITE_INDEX_CONSTRAINT_LT 16 7000#define SQLITE_INDEX_CONSTRAINT_GE 32 7001#define SQLITE_INDEX_CONSTRAINT_MATCH 64 7002#define SQLITE_INDEX_CONSTRAINT_LIKE 65 7003#define SQLITE_INDEX_CONSTRAINT_GLOB 66 7004#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 7005#define SQLITE_INDEX_CONSTRAINT_NE 68 7006#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 7007#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 7008#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 7009#define SQLITE_INDEX_CONSTRAINT_IS 72 7010#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150 7011 7012/* 7013** CAPI3REF: Register A Virtual Table Implementation 7014** METHOD: sqlite3 7015** 7016** ^These routines are used to register a new [virtual table module] name. 7017** ^Module names must be registered before 7018** creating a new [virtual table] using the module and before using a 7019** preexisting [virtual table] for the module. 7020** 7021** ^The module name is registered on the [database connection] specified 7022** by the first parameter. ^The name of the module is given by the 7023** second parameter. ^The third parameter is a pointer to 7024** the implementation of the [virtual table module]. ^The fourth 7025** parameter is an arbitrary client data pointer that is passed through 7026** into the [xCreate] and [xConnect] methods of the virtual table module 7027** when a new virtual table is be being created or reinitialized. 7028** 7029** ^The sqlite3_create_module_v2() interface has a fifth parameter which 7030** is a pointer to a destructor for the pClientData. ^SQLite will 7031** invoke the destructor function (if it is not NULL) when SQLite 7032** no longer needs the pClientData pointer. ^The destructor will also 7033** be invoked if the call to sqlite3_create_module_v2() fails. 7034** ^The sqlite3_create_module() 7035** interface is equivalent to sqlite3_create_module_v2() with a NULL 7036** destructor. 7037** 7038** ^If the third parameter (the pointer to the sqlite3_module object) is 7039** NULL then no new module is create and any existing modules with the 7040** same name are dropped. 7041** 7042** See also: [sqlite3_drop_modules()] 7043*/ 7044int sqlite3_create_module( 7045 sqlite3 *db, /* SQLite connection to register module with */ 7046 const char *zName, /* Name of the module */ 7047 const sqlite3_module *p, /* Methods for the module */ 7048 void *pClientData /* Client data for xCreate/xConnect */ 7049); 7050int sqlite3_create_module_v2( 7051 sqlite3 *db, /* SQLite connection to register module with */ 7052 const char *zName, /* Name of the module */ 7053 const sqlite3_module *p, /* Methods for the module */ 7054 void *pClientData, /* Client data for xCreate/xConnect */ 7055 void(*xDestroy)(void*) /* Module destructor function */ 7056); 7057 7058/* 7059** CAPI3REF: Remove Unnecessary Virtual Table Implementations 7060** METHOD: sqlite3 7061** 7062** ^The sqlite3_drop_modules(D,L) interface removes all virtual 7063** table modules from database connection D except those named on list L. 7064** The L parameter must be either NULL or a pointer to an array of pointers 7065** to strings where the array is terminated by a single NULL pointer. 7066** ^If the L parameter is NULL, then all virtual table modules are removed. 7067** 7068** See also: [sqlite3_create_module()] 7069*/ 7070int sqlite3_drop_modules( 7071 sqlite3 *db, /* Remove modules from this connection */ 7072 const char **azKeep /* Except, do not remove the ones named here */ 7073); 7074 7075/* 7076** CAPI3REF: Virtual Table Instance Object 7077** KEYWORDS: sqlite3_vtab 7078** 7079** Every [virtual table module] implementation uses a subclass 7080** of this object to describe a particular instance 7081** of the [virtual table]. Each subclass will 7082** be tailored to the specific needs of the module implementation. 7083** The purpose of this superclass is to define certain fields that are 7084** common to all module implementations. 7085** 7086** ^Virtual tables methods can set an error message by assigning a 7087** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 7088** take care that any prior string is freed by a call to [sqlite3_free()] 7089** prior to assigning a new string to zErrMsg. ^After the error message 7090** is delivered up to the client application, the string will be automatically 7091** freed by sqlite3_free() and the zErrMsg field will be zeroed. 7092*/ 7093struct sqlite3_vtab { 7094 const sqlite3_module *pModule; /* The module for this virtual table */ 7095 int nRef; /* Number of open cursors */ 7096 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 7097 /* Virtual table implementations will typically add additional fields */ 7098}; 7099 7100/* 7101** CAPI3REF: Virtual Table Cursor Object 7102** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 7103** 7104** Every [virtual table module] implementation uses a subclass of the 7105** following structure to describe cursors that point into the 7106** [virtual table] and are used 7107** to loop through the virtual table. Cursors are created using the 7108** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 7109** by the [sqlite3_module.xClose | xClose] method. Cursors are used 7110** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 7111** of the module. Each module implementation will define 7112** the content of a cursor structure to suit its own needs. 7113** 7114** This superclass exists in order to define fields of the cursor that 7115** are common to all implementations. 7116*/ 7117struct sqlite3_vtab_cursor { 7118 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 7119 /* Virtual table implementations will typically add additional fields */ 7120}; 7121 7122/* 7123** CAPI3REF: Declare The Schema Of A Virtual Table 7124** 7125** ^The [xCreate] and [xConnect] methods of a 7126** [virtual table module] call this interface 7127** to declare the format (the names and datatypes of the columns) of 7128** the virtual tables they implement. 7129*/ 7130int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 7131 7132/* 7133** CAPI3REF: Overload A Function For A Virtual Table 7134** METHOD: sqlite3 7135** 7136** ^(Virtual tables can provide alternative implementations of functions 7137** using the [xFindFunction] method of the [virtual table module]. 7138** But global versions of those functions 7139** must exist in order to be overloaded.)^ 7140** 7141** ^(This API makes sure a global version of a function with a particular 7142** name and number of parameters exists. If no such function exists 7143** before this API is called, a new function is created.)^ ^The implementation 7144** of the new function always causes an exception to be thrown. So 7145** the new function is not good for anything by itself. Its only 7146** purpose is to be a placeholder function that can be overloaded 7147** by a [virtual table]. 7148*/ 7149int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 7150 7151/* 7152** The interface to the virtual-table mechanism defined above (back up 7153** to a comment remarkably similar to this one) is currently considered 7154** to be experimental. The interface might change in incompatible ways. 7155** If this is a problem for you, do not use the interface at this time. 7156** 7157** When the virtual-table mechanism stabilizes, we will declare the 7158** interface fixed, support it indefinitely, and remove this comment. 7159*/ 7160 7161/* 7162** CAPI3REF: A Handle To An Open BLOB 7163** KEYWORDS: {BLOB handle} {BLOB handles} 7164** 7165** An instance of this object represents an open BLOB on which 7166** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 7167** ^Objects of this type are created by [sqlite3_blob_open()] 7168** and destroyed by [sqlite3_blob_close()]. 7169** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 7170** can be used to read or write small subsections of the BLOB. 7171** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 7172*/ 7173typedef struct sqlite3_blob sqlite3_blob; 7174 7175/* 7176** CAPI3REF: Open A BLOB For Incremental I/O 7177** METHOD: sqlite3 7178** CONSTRUCTOR: sqlite3_blob 7179** 7180** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 7181** in row iRow, column zColumn, table zTable in database zDb; 7182** in other words, the same BLOB that would be selected by: 7183** 7184** <pre> 7185** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 7186** </pre>)^ 7187** 7188** ^(Parameter zDb is not the filename that contains the database, but 7189** rather the symbolic name of the database. For attached databases, this is 7190** the name that appears after the AS keyword in the [ATTACH] statement. 7191** For the main database file, the database name is "main". For TEMP 7192** tables, the database name is "temp".)^ 7193** 7194** ^If the flags parameter is non-zero, then the BLOB is opened for read 7195** and write access. ^If the flags parameter is zero, the BLOB is opened for 7196** read-only access. 7197** 7198** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 7199** in *ppBlob. Otherwise an [error code] is returned and, unless the error 7200** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 7201** the API is not misused, it is always safe to call [sqlite3_blob_close()] 7202** on *ppBlob after this function it returns. 7203** 7204** This function fails with SQLITE_ERROR if any of the following are true: 7205** <ul> 7206** <li> ^(Database zDb does not exist)^, 7207** <li> ^(Table zTable does not exist within database zDb)^, 7208** <li> ^(Table zTable is a WITHOUT ROWID table)^, 7209** <li> ^(Column zColumn does not exist)^, 7210** <li> ^(Row iRow is not present in the table)^, 7211** <li> ^(The specified column of row iRow contains a value that is not 7212** a TEXT or BLOB value)^, 7213** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 7214** constraint and the blob is being opened for read/write access)^, 7215** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 7216** column zColumn is part of a [child key] definition and the blob is 7217** being opened for read/write access)^. 7218** </ul> 7219** 7220** ^Unless it returns SQLITE_MISUSE, this function sets the 7221** [database connection] error code and message accessible via 7222** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7223** 7224** A BLOB referenced by sqlite3_blob_open() may be read using the 7225** [sqlite3_blob_read()] interface and modified by using 7226** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 7227** different row of the same table using the [sqlite3_blob_reopen()] 7228** interface. However, the column, table, or database of a [BLOB handle] 7229** cannot be changed after the [BLOB handle] is opened. 7230** 7231** ^(If the row that a BLOB handle points to is modified by an 7232** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 7233** then the BLOB handle is marked as "expired". 7234** This is true if any column of the row is changed, even a column 7235** other than the one the BLOB handle is open on.)^ 7236** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 7237** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 7238** ^(Changes written into a BLOB prior to the BLOB expiring are not 7239** rolled back by the expiration of the BLOB. Such changes will eventually 7240** commit if the transaction continues to completion.)^ 7241** 7242** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 7243** the opened blob. ^The size of a blob may not be changed by this 7244** interface. Use the [UPDATE] SQL command to change the size of a 7245** blob. 7246** 7247** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 7248** and the built-in [zeroblob] SQL function may be used to create a 7249** zero-filled blob to read or write using the incremental-blob interface. 7250** 7251** To avoid a resource leak, every open [BLOB handle] should eventually 7252** be released by a call to [sqlite3_blob_close()]. 7253** 7254** See also: [sqlite3_blob_close()], 7255** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 7256** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 7257*/ 7258int sqlite3_blob_open( 7259 sqlite3*, 7260 const char *zDb, 7261 const char *zTable, 7262 const char *zColumn, 7263 sqlite3_int64 iRow, 7264 int flags, 7265 sqlite3_blob **ppBlob 7266); 7267 7268/* 7269** CAPI3REF: Move a BLOB Handle to a New Row 7270** METHOD: sqlite3_blob 7271** 7272** ^This function is used to move an existing [BLOB handle] so that it points 7273** to a different row of the same database table. ^The new row is identified 7274** by the rowid value passed as the second argument. Only the row can be 7275** changed. ^The database, table and column on which the blob handle is open 7276** remain the same. Moving an existing [BLOB handle] to a new row is 7277** faster than closing the existing handle and opening a new one. 7278** 7279** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 7280** it must exist and there must be either a blob or text value stored in 7281** the nominated column.)^ ^If the new row is not present in the table, or if 7282** it does not contain a blob or text value, or if another error occurs, an 7283** SQLite error code is returned and the blob handle is considered aborted. 7284** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 7285** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 7286** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 7287** always returns zero. 7288** 7289** ^This function sets the database handle error code and message. 7290*/ 7291int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 7292 7293/* 7294** CAPI3REF: Close A BLOB Handle 7295** DESTRUCTOR: sqlite3_blob 7296** 7297** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 7298** unconditionally. Even if this routine returns an error code, the 7299** handle is still closed.)^ 7300** 7301** ^If the blob handle being closed was opened for read-write access, and if 7302** the database is in auto-commit mode and there are no other open read-write 7303** blob handles or active write statements, the current transaction is 7304** committed. ^If an error occurs while committing the transaction, an error 7305** code is returned and the transaction rolled back. 7306** 7307** Calling this function with an argument that is not a NULL pointer or an 7308** open blob handle results in undefined behaviour. ^Calling this routine 7309** with a null pointer (such as would be returned by a failed call to 7310** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 7311** is passed a valid open blob handle, the values returned by the 7312** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 7313*/ 7314int sqlite3_blob_close(sqlite3_blob *); 7315 7316/* 7317** CAPI3REF: Return The Size Of An Open BLOB 7318** METHOD: sqlite3_blob 7319** 7320** ^Returns the size in bytes of the BLOB accessible via the 7321** successfully opened [BLOB handle] in its only argument. ^The 7322** incremental blob I/O routines can only read or overwriting existing 7323** blob content; they cannot change the size of a blob. 7324** 7325** This routine only works on a [BLOB handle] which has been created 7326** by a prior successful call to [sqlite3_blob_open()] and which has not 7327** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7328** to this routine results in undefined and probably undesirable behavior. 7329*/ 7330int sqlite3_blob_bytes(sqlite3_blob *); 7331 7332/* 7333** CAPI3REF: Read Data From A BLOB Incrementally 7334** METHOD: sqlite3_blob 7335** 7336** ^(This function is used to read data from an open [BLOB handle] into a 7337** caller-supplied buffer. N bytes of data are copied into buffer Z 7338** from the open BLOB, starting at offset iOffset.)^ 7339** 7340** ^If offset iOffset is less than N bytes from the end of the BLOB, 7341** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 7342** less than zero, [SQLITE_ERROR] is returned and no data is read. 7343** ^The size of the blob (and hence the maximum value of N+iOffset) 7344** can be determined using the [sqlite3_blob_bytes()] interface. 7345** 7346** ^An attempt to read from an expired [BLOB handle] fails with an 7347** error code of [SQLITE_ABORT]. 7348** 7349** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 7350** Otherwise, an [error code] or an [extended error code] is returned.)^ 7351** 7352** This routine only works on a [BLOB handle] which has been created 7353** by a prior successful call to [sqlite3_blob_open()] and which has not 7354** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7355** to this routine results in undefined and probably undesirable behavior. 7356** 7357** See also: [sqlite3_blob_write()]. 7358*/ 7359int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 7360 7361/* 7362** CAPI3REF: Write Data Into A BLOB Incrementally 7363** METHOD: sqlite3_blob 7364** 7365** ^(This function is used to write data into an open [BLOB handle] from a 7366** caller-supplied buffer. N bytes of data are copied from the buffer Z 7367** into the open BLOB, starting at offset iOffset.)^ 7368** 7369** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 7370** Otherwise, an [error code] or an [extended error code] is returned.)^ 7371** ^Unless SQLITE_MISUSE is returned, this function sets the 7372** [database connection] error code and message accessible via 7373** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7374** 7375** ^If the [BLOB handle] passed as the first argument was not opened for 7376** writing (the flags parameter to [sqlite3_blob_open()] was zero), 7377** this function returns [SQLITE_READONLY]. 7378** 7379** This function may only modify the contents of the BLOB; it is 7380** not possible to increase the size of a BLOB using this API. 7381** ^If offset iOffset is less than N bytes from the end of the BLOB, 7382** [SQLITE_ERROR] is returned and no data is written. The size of the 7383** BLOB (and hence the maximum value of N+iOffset) can be determined 7384** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 7385** than zero [SQLITE_ERROR] is returned and no data is written. 7386** 7387** ^An attempt to write to an expired [BLOB handle] fails with an 7388** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 7389** before the [BLOB handle] expired are not rolled back by the 7390** expiration of the handle, though of course those changes might 7391** have been overwritten by the statement that expired the BLOB handle 7392** or by other independent statements. 7393** 7394** This routine only works on a [BLOB handle] which has been created 7395** by a prior successful call to [sqlite3_blob_open()] and which has not 7396** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7397** to this routine results in undefined and probably undesirable behavior. 7398** 7399** See also: [sqlite3_blob_read()]. 7400*/ 7401int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 7402 7403/* 7404** CAPI3REF: Virtual File System Objects 7405** 7406** A virtual filesystem (VFS) is an [sqlite3_vfs] object 7407** that SQLite uses to interact 7408** with the underlying operating system. Most SQLite builds come with a 7409** single default VFS that is appropriate for the host computer. 7410** New VFSes can be registered and existing VFSes can be unregistered. 7411** The following interfaces are provided. 7412** 7413** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 7414** ^Names are case sensitive. 7415** ^Names are zero-terminated UTF-8 strings. 7416** ^If there is no match, a NULL pointer is returned. 7417** ^If zVfsName is NULL then the default VFS is returned. 7418** 7419** ^New VFSes are registered with sqlite3_vfs_register(). 7420** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 7421** ^The same VFS can be registered multiple times without injury. 7422** ^To make an existing VFS into the default VFS, register it again 7423** with the makeDflt flag set. If two different VFSes with the 7424** same name are registered, the behavior is undefined. If a 7425** VFS is registered with a name that is NULL or an empty string, 7426** then the behavior is undefined. 7427** 7428** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 7429** ^(If the default VFS is unregistered, another VFS is chosen as 7430** the default. The choice for the new VFS is arbitrary.)^ 7431*/ 7432sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 7433int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 7434int sqlite3_vfs_unregister(sqlite3_vfs*); 7435 7436/* 7437** CAPI3REF: Mutexes 7438** 7439** The SQLite core uses these routines for thread 7440** synchronization. Though they are intended for internal 7441** use by SQLite, code that links against SQLite is 7442** permitted to use any of these routines. 7443** 7444** The SQLite source code contains multiple implementations 7445** of these mutex routines. An appropriate implementation 7446** is selected automatically at compile-time. The following 7447** implementations are available in the SQLite core: 7448** 7449** <ul> 7450** <li> SQLITE_MUTEX_PTHREADS 7451** <li> SQLITE_MUTEX_W32 7452** <li> SQLITE_MUTEX_NOOP 7453** </ul> 7454** 7455** The SQLITE_MUTEX_NOOP implementation is a set of routines 7456** that does no real locking and is appropriate for use in 7457** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 7458** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 7459** and Windows. 7460** 7461** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 7462** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 7463** implementation is included with the library. In this case the 7464** application must supply a custom mutex implementation using the 7465** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 7466** before calling sqlite3_initialize() or any other public sqlite3_ 7467** function that calls sqlite3_initialize(). 7468** 7469** ^The sqlite3_mutex_alloc() routine allocates a new 7470** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 7471** routine returns NULL if it is unable to allocate the requested 7472** mutex. The argument to sqlite3_mutex_alloc() must one of these 7473** integer constants: 7474** 7475** <ul> 7476** <li> SQLITE_MUTEX_FAST 7477** <li> SQLITE_MUTEX_RECURSIVE 7478** <li> SQLITE_MUTEX_STATIC_MAIN 7479** <li> SQLITE_MUTEX_STATIC_MEM 7480** <li> SQLITE_MUTEX_STATIC_OPEN 7481** <li> SQLITE_MUTEX_STATIC_PRNG 7482** <li> SQLITE_MUTEX_STATIC_LRU 7483** <li> SQLITE_MUTEX_STATIC_PMEM 7484** <li> SQLITE_MUTEX_STATIC_APP1 7485** <li> SQLITE_MUTEX_STATIC_APP2 7486** <li> SQLITE_MUTEX_STATIC_APP3 7487** <li> SQLITE_MUTEX_STATIC_VFS1 7488** <li> SQLITE_MUTEX_STATIC_VFS2 7489** <li> SQLITE_MUTEX_STATIC_VFS3 7490** </ul> 7491** 7492** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 7493** cause sqlite3_mutex_alloc() to create 7494** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 7495** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 7496** The mutex implementation does not need to make a distinction 7497** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 7498** not want to. SQLite will only request a recursive mutex in 7499** cases where it really needs one. If a faster non-recursive mutex 7500** implementation is available on the host platform, the mutex subsystem 7501** might return such a mutex in response to SQLITE_MUTEX_FAST. 7502** 7503** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 7504** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 7505** a pointer to a static preexisting mutex. ^Nine static mutexes are 7506** used by the current version of SQLite. Future versions of SQLite 7507** may add additional static mutexes. Static mutexes are for internal 7508** use by SQLite only. Applications that use SQLite mutexes should 7509** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 7510** SQLITE_MUTEX_RECURSIVE. 7511** 7512** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 7513** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 7514** returns a different mutex on every call. ^For the static 7515** mutex types, the same mutex is returned on every call that has 7516** the same type number. 7517** 7518** ^The sqlite3_mutex_free() routine deallocates a previously 7519** allocated dynamic mutex. Attempting to deallocate a static 7520** mutex results in undefined behavior. 7521** 7522** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 7523** to enter a mutex. ^If another thread is already within the mutex, 7524** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 7525** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 7526** upon successful entry. ^(Mutexes created using 7527** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 7528** In such cases, the 7529** mutex must be exited an equal number of times before another thread 7530** can enter.)^ If the same thread tries to enter any mutex other 7531** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 7532** 7533** ^(Some systems (for example, Windows 95) do not support the operation 7534** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 7535** will always return SQLITE_BUSY. The SQLite core only ever uses 7536** sqlite3_mutex_try() as an optimization so this is acceptable 7537** behavior.)^ 7538** 7539** ^The sqlite3_mutex_leave() routine exits a mutex that was 7540** previously entered by the same thread. The behavior 7541** is undefined if the mutex is not currently entered by the 7542** calling thread or is not currently allocated. 7543** 7544** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 7545** sqlite3_mutex_leave() is a NULL pointer, then all three routines 7546** behave as no-ops. 7547** 7548** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 7549*/ 7550sqlite3_mutex *sqlite3_mutex_alloc(int); 7551void sqlite3_mutex_free(sqlite3_mutex*); 7552void sqlite3_mutex_enter(sqlite3_mutex*); 7553int sqlite3_mutex_try(sqlite3_mutex*); 7554void sqlite3_mutex_leave(sqlite3_mutex*); 7555 7556/* 7557** CAPI3REF: Mutex Methods Object 7558** 7559** An instance of this structure defines the low-level routines 7560** used to allocate and use mutexes. 7561** 7562** Usually, the default mutex implementations provided by SQLite are 7563** sufficient, however the application has the option of substituting a custom 7564** implementation for specialized deployments or systems for which SQLite 7565** does not provide a suitable implementation. In this case, the application 7566** creates and populates an instance of this structure to pass 7567** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 7568** Additionally, an instance of this structure can be used as an 7569** output variable when querying the system for the current mutex 7570** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 7571** 7572** ^The xMutexInit method defined by this structure is invoked as 7573** part of system initialization by the sqlite3_initialize() function. 7574** ^The xMutexInit routine is called by SQLite exactly once for each 7575** effective call to [sqlite3_initialize()]. 7576** 7577** ^The xMutexEnd method defined by this structure is invoked as 7578** part of system shutdown by the sqlite3_shutdown() function. The 7579** implementation of this method is expected to release all outstanding 7580** resources obtained by the mutex methods implementation, especially 7581** those obtained by the xMutexInit method. ^The xMutexEnd() 7582** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 7583** 7584** ^(The remaining seven methods defined by this structure (xMutexAlloc, 7585** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 7586** xMutexNotheld) implement the following interfaces (respectively): 7587** 7588** <ul> 7589** <li> [sqlite3_mutex_alloc()] </li> 7590** <li> [sqlite3_mutex_free()] </li> 7591** <li> [sqlite3_mutex_enter()] </li> 7592** <li> [sqlite3_mutex_try()] </li> 7593** <li> [sqlite3_mutex_leave()] </li> 7594** <li> [sqlite3_mutex_held()] </li> 7595** <li> [sqlite3_mutex_notheld()] </li> 7596** </ul>)^ 7597** 7598** The only difference is that the public sqlite3_XXX functions enumerated 7599** above silently ignore any invocations that pass a NULL pointer instead 7600** of a valid mutex handle. The implementations of the methods defined 7601** by this structure are not required to handle this case. The results 7602** of passing a NULL pointer instead of a valid mutex handle are undefined 7603** (i.e. it is acceptable to provide an implementation that segfaults if 7604** it is passed a NULL pointer). 7605** 7606** The xMutexInit() method must be threadsafe. It must be harmless to 7607** invoke xMutexInit() multiple times within the same process and without 7608** intervening calls to xMutexEnd(). Second and subsequent calls to 7609** xMutexInit() must be no-ops. 7610** 7611** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 7612** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 7613** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 7614** memory allocation for a fast or recursive mutex. 7615** 7616** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 7617** called, but only if the prior call to xMutexInit returned SQLITE_OK. 7618** If xMutexInit fails in any way, it is expected to clean up after itself 7619** prior to returning. 7620*/ 7621typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 7622struct sqlite3_mutex_methods { 7623 int (*xMutexInit)(void); 7624 int (*xMutexEnd)(void); 7625 sqlite3_mutex *(*xMutexAlloc)(int); 7626 void (*xMutexFree)(sqlite3_mutex *); 7627 void (*xMutexEnter)(sqlite3_mutex *); 7628 int (*xMutexTry)(sqlite3_mutex *); 7629 void (*xMutexLeave)(sqlite3_mutex *); 7630 int (*xMutexHeld)(sqlite3_mutex *); 7631 int (*xMutexNotheld)(sqlite3_mutex *); 7632}; 7633 7634/* 7635** CAPI3REF: Mutex Verification Routines 7636** 7637** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 7638** are intended for use inside assert() statements. The SQLite core 7639** never uses these routines except inside an assert() and applications 7640** are advised to follow the lead of the core. The SQLite core only 7641** provides implementations for these routines when it is compiled 7642** with the SQLITE_DEBUG flag. External mutex implementations 7643** are only required to provide these routines if SQLITE_DEBUG is 7644** defined and if NDEBUG is not defined. 7645** 7646** These routines should return true if the mutex in their argument 7647** is held or not held, respectively, by the calling thread. 7648** 7649** The implementation is not required to provide versions of these 7650** routines that actually work. If the implementation does not provide working 7651** versions of these routines, it should at least provide stubs that always 7652** return true so that one does not get spurious assertion failures. 7653** 7654** If the argument to sqlite3_mutex_held() is a NULL pointer then 7655** the routine should return 1. This seems counter-intuitive since 7656** clearly the mutex cannot be held if it does not exist. But 7657** the reason the mutex does not exist is because the build is not 7658** using mutexes. And we do not want the assert() containing the 7659** call to sqlite3_mutex_held() to fail, so a non-zero return is 7660** the appropriate thing to do. The sqlite3_mutex_notheld() 7661** interface should also return 1 when given a NULL pointer. 7662*/ 7663#ifndef NDEBUG 7664int sqlite3_mutex_held(sqlite3_mutex*); 7665int sqlite3_mutex_notheld(sqlite3_mutex*); 7666#endif 7667 7668/* 7669** CAPI3REF: Mutex Types 7670** 7671** The [sqlite3_mutex_alloc()] interface takes a single argument 7672** which is one of these integer constants. 7673** 7674** The set of static mutexes may change from one SQLite release to the 7675** next. Applications that override the built-in mutex logic must be 7676** prepared to accommodate additional static mutexes. 7677*/ 7678#define SQLITE_MUTEX_FAST 0 7679#define SQLITE_MUTEX_RECURSIVE 1 7680#define SQLITE_MUTEX_STATIC_MAIN 2 7681#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 7682#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 7683#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 7684#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 7685#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 7686#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 7687#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 7688#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 7689#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 7690#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 7691#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 7692#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 7693#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 7694 7695/* Legacy compatibility: */ 7696#define SQLITE_MUTEX_STATIC_MASTER 2 7697 7698 7699/* 7700** CAPI3REF: Retrieve the mutex for a database connection 7701** METHOD: sqlite3 7702** 7703** ^This interface returns a pointer the [sqlite3_mutex] object that 7704** serializes access to the [database connection] given in the argument 7705** when the [threading mode] is Serialized. 7706** ^If the [threading mode] is Single-thread or Multi-thread then this 7707** routine returns a NULL pointer. 7708*/ 7709sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 7710 7711/* 7712** CAPI3REF: Low-Level Control Of Database Files 7713** METHOD: sqlite3 7714** KEYWORDS: {file control} 7715** 7716** ^The [sqlite3_file_control()] interface makes a direct call to the 7717** xFileControl method for the [sqlite3_io_methods] object associated 7718** with a particular database identified by the second argument. ^The 7719** name of the database is "main" for the main database or "temp" for the 7720** TEMP database, or the name that appears after the AS keyword for 7721** databases that are added using the [ATTACH] SQL command. 7722** ^A NULL pointer can be used in place of "main" to refer to the 7723** main database file. 7724** ^The third and fourth parameters to this routine 7725** are passed directly through to the second and third parameters of 7726** the xFileControl method. ^The return value of the xFileControl 7727** method becomes the return value of this routine. 7728** 7729** A few opcodes for [sqlite3_file_control()] are handled directly 7730** by the SQLite core and never invoke the 7731** sqlite3_io_methods.xFileControl method. 7732** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 7733** a pointer to the underlying [sqlite3_file] object to be written into 7734** the space pointed to by the 4th parameter. The 7735** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns 7736** the [sqlite3_file] object associated with the journal file instead of 7737** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns 7738** a pointer to the underlying [sqlite3_vfs] object for the file. 7739** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter 7740** from the pager. 7741** 7742** ^If the second parameter (zDbName) does not match the name of any 7743** open database file, then SQLITE_ERROR is returned. ^This error 7744** code is not remembered and will not be recalled by [sqlite3_errcode()] 7745** or [sqlite3_errmsg()]. The underlying xFileControl method might 7746** also return SQLITE_ERROR. There is no way to distinguish between 7747** an incorrect zDbName and an SQLITE_ERROR return from the underlying 7748** xFileControl method. 7749** 7750** See also: [file control opcodes] 7751*/ 7752int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 7753 7754/* 7755** CAPI3REF: Testing Interface 7756** 7757** ^The sqlite3_test_control() interface is used to read out internal 7758** state of SQLite and to inject faults into SQLite for testing 7759** purposes. ^The first parameter is an operation code that determines 7760** the number, meaning, and operation of all subsequent parameters. 7761** 7762** This interface is not for use by applications. It exists solely 7763** for verifying the correct operation of the SQLite library. Depending 7764** on how the SQLite library is compiled, this interface might not exist. 7765** 7766** The details of the operation codes, their meanings, the parameters 7767** they take, and what they do are all subject to change without notice. 7768** Unlike most of the SQLite API, this function is not guaranteed to 7769** operate consistently from one release to the next. 7770*/ 7771int sqlite3_test_control(int op, ...); 7772 7773/* 7774** CAPI3REF: Testing Interface Operation Codes 7775** 7776** These constants are the valid operation code parameters used 7777** as the first argument to [sqlite3_test_control()]. 7778** 7779** These parameters and their meanings are subject to change 7780** without notice. These values are for testing purposes only. 7781** Applications should not use any of these parameters or the 7782** [sqlite3_test_control()] interface. 7783*/ 7784#define SQLITE_TESTCTRL_FIRST 5 7785#define SQLITE_TESTCTRL_PRNG_SAVE 5 7786#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7787#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */ 7788#define SQLITE_TESTCTRL_BITVEC_TEST 8 7789#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7790#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7791#define SQLITE_TESTCTRL_PENDING_BYTE 11 7792#define SQLITE_TESTCTRL_ASSERT 12 7793#define SQLITE_TESTCTRL_ALWAYS 13 7794#define SQLITE_TESTCTRL_RESERVE 14 /* NOT USED */ 7795#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7796#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */ 7797#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7798#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17 7799#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7800#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7801#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7802#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7803#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7804#define SQLITE_TESTCTRL_BYTEORDER 22 7805#define SQLITE_TESTCTRL_ISINIT 23 7806#define SQLITE_TESTCTRL_SORTER_MMAP 24 7807#define SQLITE_TESTCTRL_IMPOSTER 25 7808#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7809#define SQLITE_TESTCTRL_RESULT_INTREAL 27 7810#define SQLITE_TESTCTRL_PRNG_SEED 28 7811#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29 7812#define SQLITE_TESTCTRL_SEEK_COUNT 30 7813#define SQLITE_TESTCTRL_TRACEFLAGS 31 7814#define SQLITE_TESTCTRL_LAST 31 /* Largest TESTCTRL */ 7815 7816/* 7817** CAPI3REF: SQL Keyword Checking 7818** 7819** These routines provide access to the set of SQL language keywords 7820** recognized by SQLite. Applications can uses these routines to determine 7821** whether or not a specific identifier needs to be escaped (for example, 7822** by enclosing in double-quotes) so as not to confuse the parser. 7823** 7824** The sqlite3_keyword_count() interface returns the number of distinct 7825** keywords understood by SQLite. 7826** 7827** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and 7828** makes *Z point to that keyword expressed as UTF8 and writes the number 7829** of bytes in the keyword into *L. The string that *Z points to is not 7830** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns 7831** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z 7832** or L are NULL or invalid pointers then calls to 7833** sqlite3_keyword_name(N,Z,L) result in undefined behavior. 7834** 7835** The sqlite3_keyword_check(Z,L) interface checks to see whether or not 7836** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero 7837** if it is and zero if not. 7838** 7839** The parser used by SQLite is forgiving. It is often possible to use 7840** a keyword as an identifier as long as such use does not result in a 7841** parsing ambiguity. For example, the statement 7842** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and 7843** creates a new table named "BEGIN" with three columns named 7844** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid 7845** using keywords as identifiers. Common techniques used to avoid keyword 7846** name collisions include: 7847** <ul> 7848** <li> Put all identifier names inside double-quotes. This is the official 7849** SQL way to escape identifier names. 7850** <li> Put identifier names inside [...]. This is not standard SQL, 7851** but it is what SQL Server does and so lots of programmers use this 7852** technique. 7853** <li> Begin every identifier with the letter "Z" as no SQL keywords start 7854** with "Z". 7855** <li> Include a digit somewhere in every identifier name. 7856** </ul> 7857** 7858** Note that the number of keywords understood by SQLite can depend on 7859** compile-time options. For example, "VACUUM" is not a keyword if 7860** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also, 7861** new keywords may be added to future releases of SQLite. 7862*/ 7863int sqlite3_keyword_count(void); 7864int sqlite3_keyword_name(int,const char**,int*); 7865int sqlite3_keyword_check(const char*,int); 7866 7867/* 7868** CAPI3REF: Dynamic String Object 7869** KEYWORDS: {dynamic string} 7870** 7871** An instance of the sqlite3_str object contains a dynamically-sized 7872** string under construction. 7873** 7874** The lifecycle of an sqlite3_str object is as follows: 7875** <ol> 7876** <li> ^The sqlite3_str object is created using [sqlite3_str_new()]. 7877** <li> ^Text is appended to the sqlite3_str object using various 7878** methods, such as [sqlite3_str_appendf()]. 7879** <li> ^The sqlite3_str object is destroyed and the string it created 7880** is returned using the [sqlite3_str_finish()] interface. 7881** </ol> 7882*/ 7883typedef struct sqlite3_str sqlite3_str; 7884 7885/* 7886** CAPI3REF: Create A New Dynamic String Object 7887** CONSTRUCTOR: sqlite3_str 7888** 7889** ^The [sqlite3_str_new(D)] interface allocates and initializes 7890** a new [sqlite3_str] object. To avoid memory leaks, the object returned by 7891** [sqlite3_str_new()] must be freed by a subsequent call to 7892** [sqlite3_str_finish(X)]. 7893** 7894** ^The [sqlite3_str_new(D)] interface always returns a pointer to a 7895** valid [sqlite3_str] object, though in the event of an out-of-memory 7896** error the returned object might be a special singleton that will 7897** silently reject new text, always return SQLITE_NOMEM from 7898** [sqlite3_str_errcode()], always return 0 for 7899** [sqlite3_str_length()], and always return NULL from 7900** [sqlite3_str_finish(X)]. It is always safe to use the value 7901** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter 7902** to any of the other [sqlite3_str] methods. 7903** 7904** The D parameter to [sqlite3_str_new(D)] may be NULL. If the 7905** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum 7906** length of the string contained in the [sqlite3_str] object will be 7907** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead 7908** of [SQLITE_MAX_LENGTH]. 7909*/ 7910sqlite3_str *sqlite3_str_new(sqlite3*); 7911 7912/* 7913** CAPI3REF: Finalize A Dynamic String 7914** DESTRUCTOR: sqlite3_str 7915** 7916** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X 7917** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()] 7918** that contains the constructed string. The calling application should 7919** pass the returned value to [sqlite3_free()] to avoid a memory leak. 7920** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any 7921** errors were encountered during construction of the string. ^The 7922** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the 7923** string in [sqlite3_str] object X is zero bytes long. 7924*/ 7925char *sqlite3_str_finish(sqlite3_str*); 7926 7927/* 7928** CAPI3REF: Add Content To A Dynamic String 7929** METHOD: sqlite3_str 7930** 7931** These interfaces add content to an sqlite3_str object previously obtained 7932** from [sqlite3_str_new()]. 7933** 7934** ^The [sqlite3_str_appendf(X,F,...)] and 7935** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf] 7936** functionality of SQLite to append formatted text onto the end of 7937** [sqlite3_str] object X. 7938** 7939** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S 7940** onto the end of the [sqlite3_str] object X. N must be non-negative. 7941** S must contain at least N non-zero bytes of content. To append a 7942** zero-terminated string in its entirety, use the [sqlite3_str_appendall()] 7943** method instead. 7944** 7945** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of 7946** zero-terminated string S onto the end of [sqlite3_str] object X. 7947** 7948** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the 7949** single-byte character C onto the end of [sqlite3_str] object X. 7950** ^This method can be used, for example, to add whitespace indentation. 7951** 7952** ^The [sqlite3_str_reset(X)] method resets the string under construction 7953** inside [sqlite3_str] object X back to zero bytes in length. 7954** 7955** These methods do not return a result code. ^If an error occurs, that fact 7956** is recorded in the [sqlite3_str] object and can be recovered by a 7957** subsequent call to [sqlite3_str_errcode(X)]. 7958*/ 7959void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...); 7960void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list); 7961void sqlite3_str_append(sqlite3_str*, const char *zIn, int N); 7962void sqlite3_str_appendall(sqlite3_str*, const char *zIn); 7963void sqlite3_str_appendchar(sqlite3_str*, int N, char C); 7964void sqlite3_str_reset(sqlite3_str*); 7965 7966/* 7967** CAPI3REF: Status Of A Dynamic String 7968** METHOD: sqlite3_str 7969** 7970** These interfaces return the current status of an [sqlite3_str] object. 7971** 7972** ^If any prior errors have occurred while constructing the dynamic string 7973** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return 7974** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns 7975** [SQLITE_NOMEM] following any out-of-memory error, or 7976** [SQLITE_TOOBIG] if the size of the dynamic string exceeds 7977** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors. 7978** 7979** ^The [sqlite3_str_length(X)] method returns the current length, in bytes, 7980** of the dynamic string under construction in [sqlite3_str] object X. 7981** ^The length returned by [sqlite3_str_length(X)] does not include the 7982** zero-termination byte. 7983** 7984** ^The [sqlite3_str_value(X)] method returns a pointer to the current 7985** content of the dynamic string under construction in X. The value 7986** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X 7987** and might be freed or altered by any subsequent method on the same 7988** [sqlite3_str] object. Applications must not used the pointer returned 7989** [sqlite3_str_value(X)] after any subsequent method call on the same 7990** object. ^Applications may change the content of the string returned 7991** by [sqlite3_str_value(X)] as long as they do not write into any bytes 7992** outside the range of 0 to [sqlite3_str_length(X)] and do not read or 7993** write any byte after any subsequent sqlite3_str method call. 7994*/ 7995int sqlite3_str_errcode(sqlite3_str*); 7996int sqlite3_str_length(sqlite3_str*); 7997char *sqlite3_str_value(sqlite3_str*); 7998 7999/* 8000** CAPI3REF: SQLite Runtime Status 8001** 8002** ^These interfaces are used to retrieve runtime status information 8003** about the performance of SQLite, and optionally to reset various 8004** highwater marks. ^The first argument is an integer code for 8005** the specific parameter to measure. ^(Recognized integer codes 8006** are of the form [status parameters | SQLITE_STATUS_...].)^ 8007** ^The current value of the parameter is returned into *pCurrent. 8008** ^The highest recorded value is returned in *pHighwater. ^If the 8009** resetFlag is true, then the highest record value is reset after 8010** *pHighwater is written. ^(Some parameters do not record the highest 8011** value. For those parameters 8012** nothing is written into *pHighwater and the resetFlag is ignored.)^ 8013** ^(Other parameters record only the highwater mark and not the current 8014** value. For these latter parameters nothing is written into *pCurrent.)^ 8015** 8016** ^The sqlite3_status() and sqlite3_status64() routines return 8017** SQLITE_OK on success and a non-zero [error code] on failure. 8018** 8019** If either the current value or the highwater mark is too large to 8020** be represented by a 32-bit integer, then the values returned by 8021** sqlite3_status() are undefined. 8022** 8023** See also: [sqlite3_db_status()] 8024*/ 8025int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 8026int sqlite3_status64( 8027 int op, 8028 sqlite3_int64 *pCurrent, 8029 sqlite3_int64 *pHighwater, 8030 int resetFlag 8031); 8032 8033 8034/* 8035** CAPI3REF: Status Parameters 8036** KEYWORDS: {status parameters} 8037** 8038** These integer constants designate various run-time status parameters 8039** that can be returned by [sqlite3_status()]. 8040** 8041** <dl> 8042** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 8043** <dd>This parameter is the current amount of memory checked out 8044** using [sqlite3_malloc()], either directly or indirectly. The 8045** figure includes calls made to [sqlite3_malloc()] by the application 8046** and internal memory usage by the SQLite library. Auxiliary page-cache 8047** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 8048** this parameter. The amount returned is the sum of the allocation 8049** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 8050** 8051** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 8052** <dd>This parameter records the largest memory allocation request 8053** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 8054** internal equivalents). Only the value returned in the 8055** *pHighwater parameter to [sqlite3_status()] is of interest. 8056** The value written into the *pCurrent parameter is undefined.</dd>)^ 8057** 8058** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 8059** <dd>This parameter records the number of separate memory allocations 8060** currently checked out.</dd>)^ 8061** 8062** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 8063** <dd>This parameter returns the number of pages used out of the 8064** [pagecache memory allocator] that was configured using 8065** [SQLITE_CONFIG_PAGECACHE]. The 8066** value returned is in pages, not in bytes.</dd>)^ 8067** 8068** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 8069** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 8070** <dd>This parameter returns the number of bytes of page cache 8071** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 8072** buffer and where forced to overflow to [sqlite3_malloc()]. The 8073** returned value includes allocations that overflowed because they 8074** where too large (they were larger than the "sz" parameter to 8075** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 8076** no space was left in the page cache.</dd>)^ 8077** 8078** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 8079** <dd>This parameter records the largest memory allocation request 8080** handed to the [pagecache memory allocator]. Only the value returned in the 8081** *pHighwater parameter to [sqlite3_status()] is of interest. 8082** The value written into the *pCurrent parameter is undefined.</dd>)^ 8083** 8084** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 8085** <dd>No longer used.</dd> 8086** 8087** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 8088** <dd>No longer used.</dd> 8089** 8090** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 8091** <dd>No longer used.</dd> 8092** 8093** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 8094** <dd>The *pHighwater parameter records the deepest parser stack. 8095** The *pCurrent value is undefined. The *pHighwater value is only 8096** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 8097** </dl> 8098** 8099** New status parameters may be added from time to time. 8100*/ 8101#define SQLITE_STATUS_MEMORY_USED 0 8102#define SQLITE_STATUS_PAGECACHE_USED 1 8103#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 8104#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 8105#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 8106#define SQLITE_STATUS_MALLOC_SIZE 5 8107#define SQLITE_STATUS_PARSER_STACK 6 8108#define SQLITE_STATUS_PAGECACHE_SIZE 7 8109#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 8110#define SQLITE_STATUS_MALLOC_COUNT 9 8111 8112/* 8113** CAPI3REF: Database Connection Status 8114** METHOD: sqlite3 8115** 8116** ^This interface is used to retrieve runtime status information 8117** about a single [database connection]. ^The first argument is the 8118** database connection object to be interrogated. ^The second argument 8119** is an integer constant, taken from the set of 8120** [SQLITE_DBSTATUS options], that 8121** determines the parameter to interrogate. The set of 8122** [SQLITE_DBSTATUS options] is likely 8123** to grow in future releases of SQLite. 8124** 8125** ^The current value of the requested parameter is written into *pCur 8126** and the highest instantaneous value is written into *pHiwtr. ^If 8127** the resetFlg is true, then the highest instantaneous value is 8128** reset back down to the current value. 8129** 8130** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 8131** non-zero [error code] on failure. 8132** 8133** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 8134*/ 8135int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 8136 8137/* 8138** CAPI3REF: Status Parameters for database connections 8139** KEYWORDS: {SQLITE_DBSTATUS options} 8140** 8141** These constants are the available integer "verbs" that can be passed as 8142** the second argument to the [sqlite3_db_status()] interface. 8143** 8144** New verbs may be added in future releases of SQLite. Existing verbs 8145** might be discontinued. Applications should check the return code from 8146** [sqlite3_db_status()] to make sure that the call worked. 8147** The [sqlite3_db_status()] interface will return a non-zero error code 8148** if a discontinued or unsupported verb is invoked. 8149** 8150** <dl> 8151** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 8152** <dd>This parameter returns the number of lookaside memory slots currently 8153** checked out.</dd>)^ 8154** 8155** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 8156** <dd>This parameter returns the number of malloc attempts that were 8157** satisfied using lookaside memory. Only the high-water value is meaningful; 8158** the current value is always zero.)^ 8159** 8160** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 8161** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 8162** <dd>This parameter returns the number malloc attempts that might have 8163** been satisfied using lookaside memory but failed due to the amount of 8164** memory requested being larger than the lookaside slot size. 8165** Only the high-water value is meaningful; 8166** the current value is always zero.)^ 8167** 8168** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 8169** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 8170** <dd>This parameter returns the number malloc attempts that might have 8171** been satisfied using lookaside memory but failed due to all lookaside 8172** memory already being in use. 8173** Only the high-water value is meaningful; 8174** the current value is always zero.)^ 8175** 8176** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 8177** <dd>This parameter returns the approximate number of bytes of heap 8178** memory used by all pager caches associated with the database connection.)^ 8179** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 8180** 8181** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 8182** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 8183** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 8184** pager cache is shared between two or more connections the bytes of heap 8185** memory used by that pager cache is divided evenly between the attached 8186** connections.)^ In other words, if none of the pager caches associated 8187** with the database connection are shared, this request returns the same 8188** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 8189** shared, the value returned by this call will be smaller than that returned 8190** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 8191** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 8192** 8193** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 8194** <dd>This parameter returns the approximate number of bytes of heap 8195** memory used to store the schema for all databases associated 8196** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 8197** ^The full amount of memory used by the schemas is reported, even if the 8198** schema memory is shared with other database connections due to 8199** [shared cache mode] being enabled. 8200** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 8201** 8202** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 8203** <dd>This parameter returns the approximate number of bytes of heap 8204** and lookaside memory used by all prepared statements associated with 8205** the database connection.)^ 8206** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 8207** </dd> 8208** 8209** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 8210** <dd>This parameter returns the number of pager cache hits that have 8211** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 8212** is always 0. 8213** </dd> 8214** 8215** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 8216** <dd>This parameter returns the number of pager cache misses that have 8217** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 8218** is always 0. 8219** </dd> 8220** 8221** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 8222** <dd>This parameter returns the number of dirty cache entries that have 8223** been written to disk. Specifically, the number of pages written to the 8224** wal file in wal mode databases, or the number of pages written to the 8225** database file in rollback mode databases. Any pages written as part of 8226** transaction rollback or database recovery operations are not included. 8227** If an IO or other error occurs while writing a page to disk, the effect 8228** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 8229** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 8230** </dd> 8231** 8232** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 8233** <dd>This parameter returns the number of dirty cache entries that have 8234** been written to disk in the middle of a transaction due to the page 8235** cache overflowing. Transactions are more efficient if they are written 8236** to disk all at once. When pages spill mid-transaction, that introduces 8237** additional overhead. This parameter can be used help identify 8238** inefficiencies that can be resolved by increasing the cache size. 8239** </dd> 8240** 8241** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 8242** <dd>This parameter returns zero for the current value if and only if 8243** all foreign key constraints (deferred or immediate) have been 8244** resolved.)^ ^The highwater mark is always 0. 8245** </dd> 8246** </dl> 8247*/ 8248#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 8249#define SQLITE_DBSTATUS_CACHE_USED 1 8250#define SQLITE_DBSTATUS_SCHEMA_USED 2 8251#define SQLITE_DBSTATUS_STMT_USED 3 8252#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 8253#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 8254#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 8255#define SQLITE_DBSTATUS_CACHE_HIT 7 8256#define SQLITE_DBSTATUS_CACHE_MISS 8 8257#define SQLITE_DBSTATUS_CACHE_WRITE 9 8258#define SQLITE_DBSTATUS_DEFERRED_FKS 10 8259#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 8260#define SQLITE_DBSTATUS_CACHE_SPILL 12 8261#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 8262 8263 8264/* 8265** CAPI3REF: Prepared Statement Status 8266** METHOD: sqlite3_stmt 8267** 8268** ^(Each prepared statement maintains various 8269** [SQLITE_STMTSTATUS counters] that measure the number 8270** of times it has performed specific operations.)^ These counters can 8271** be used to monitor the performance characteristics of the prepared 8272** statements. For example, if the number of table steps greatly exceeds 8273** the number of table searches or result rows, that would tend to indicate 8274** that the prepared statement is using a full table scan rather than 8275** an index. 8276** 8277** ^(This interface is used to retrieve and reset counter values from 8278** a [prepared statement]. The first argument is the prepared statement 8279** object to be interrogated. The second argument 8280** is an integer code for a specific [SQLITE_STMTSTATUS counter] 8281** to be interrogated.)^ 8282** ^The current value of the requested counter is returned. 8283** ^If the resetFlg is true, then the counter is reset to zero after this 8284** interface call returns. 8285** 8286** See also: [sqlite3_status()] and [sqlite3_db_status()]. 8287*/ 8288int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 8289 8290/* 8291** CAPI3REF: Status Parameters for prepared statements 8292** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 8293** 8294** These preprocessor macros define integer codes that name counter 8295** values associated with the [sqlite3_stmt_status()] interface. 8296** The meanings of the various counters are as follows: 8297** 8298** <dl> 8299** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 8300** <dd>^This is the number of times that SQLite has stepped forward in 8301** a table as part of a full table scan. Large numbers for this counter 8302** may indicate opportunities for performance improvement through 8303** careful use of indices.</dd> 8304** 8305** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 8306** <dd>^This is the number of sort operations that have occurred. 8307** A non-zero value in this counter may indicate an opportunity to 8308** improvement performance through careful use of indices.</dd> 8309** 8310** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 8311** <dd>^This is the number of rows inserted into transient indices that 8312** were created automatically in order to help joins run faster. 8313** A non-zero value in this counter may indicate an opportunity to 8314** improvement performance by adding permanent indices that do not 8315** need to be reinitialized each time the statement is run.</dd> 8316** 8317** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 8318** <dd>^This is the number of virtual machine operations executed 8319** by the prepared statement if that number is less than or equal 8320** to 2147483647. The number of virtual machine operations can be 8321** used as a proxy for the total work done by the prepared statement. 8322** If the number of virtual machine operations exceeds 2147483647 8323** then the value returned by this statement status code is undefined. 8324** 8325** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 8326** <dd>^This is the number of times that the prepare statement has been 8327** automatically regenerated due to schema changes or changes to 8328** [bound parameters] that might affect the query plan. 8329** 8330** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 8331** <dd>^This is the number of times that the prepared statement has 8332** been run. A single "run" for the purposes of this counter is one 8333** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 8334** The counter is incremented on the first [sqlite3_step()] call of each 8335** cycle. 8336** 8337** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 8338** <dd>^This is the approximate number of bytes of heap memory 8339** used to store the prepared statement. ^This value is not actually 8340** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 8341** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 8342** </dd> 8343** </dl> 8344*/ 8345#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 8346#define SQLITE_STMTSTATUS_SORT 2 8347#define SQLITE_STMTSTATUS_AUTOINDEX 3 8348#define SQLITE_STMTSTATUS_VM_STEP 4 8349#define SQLITE_STMTSTATUS_REPREPARE 5 8350#define SQLITE_STMTSTATUS_RUN 6 8351#define SQLITE_STMTSTATUS_MEMUSED 99 8352 8353/* 8354** CAPI3REF: Custom Page Cache Object 8355** 8356** The sqlite3_pcache type is opaque. It is implemented by 8357** the pluggable module. The SQLite core has no knowledge of 8358** its size or internal structure and never deals with the 8359** sqlite3_pcache object except by holding and passing pointers 8360** to the object. 8361** 8362** See [sqlite3_pcache_methods2] for additional information. 8363*/ 8364typedef struct sqlite3_pcache sqlite3_pcache; 8365 8366/* 8367** CAPI3REF: Custom Page Cache Object 8368** 8369** The sqlite3_pcache_page object represents a single page in the 8370** page cache. The page cache will allocate instances of this 8371** object. Various methods of the page cache use pointers to instances 8372** of this object as parameters or as their return value. 8373** 8374** See [sqlite3_pcache_methods2] for additional information. 8375*/ 8376typedef struct sqlite3_pcache_page sqlite3_pcache_page; 8377struct sqlite3_pcache_page { 8378 void *pBuf; /* The content of the page */ 8379 void *pExtra; /* Extra information associated with the page */ 8380}; 8381 8382/* 8383** CAPI3REF: Application Defined Page Cache. 8384** KEYWORDS: {page cache} 8385** 8386** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 8387** register an alternative page cache implementation by passing in an 8388** instance of the sqlite3_pcache_methods2 structure.)^ 8389** In many applications, most of the heap memory allocated by 8390** SQLite is used for the page cache. 8391** By implementing a 8392** custom page cache using this API, an application can better control 8393** the amount of memory consumed by SQLite, the way in which 8394** that memory is allocated and released, and the policies used to 8395** determine exactly which parts of a database file are cached and for 8396** how long. 8397** 8398** The alternative page cache mechanism is an 8399** extreme measure that is only needed by the most demanding applications. 8400** The built-in page cache is recommended for most uses. 8401** 8402** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 8403** internal buffer by SQLite within the call to [sqlite3_config]. Hence 8404** the application may discard the parameter after the call to 8405** [sqlite3_config()] returns.)^ 8406** 8407** [[the xInit() page cache method]] 8408** ^(The xInit() method is called once for each effective 8409** call to [sqlite3_initialize()])^ 8410** (usually only once during the lifetime of the process). ^(The xInit() 8411** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 8412** The intent of the xInit() method is to set up global data structures 8413** required by the custom page cache implementation. 8414** ^(If the xInit() method is NULL, then the 8415** built-in default page cache is used instead of the application defined 8416** page cache.)^ 8417** 8418** [[the xShutdown() page cache method]] 8419** ^The xShutdown() method is called by [sqlite3_shutdown()]. 8420** It can be used to clean up 8421** any outstanding resources before process shutdown, if required. 8422** ^The xShutdown() method may be NULL. 8423** 8424** ^SQLite automatically serializes calls to the xInit method, 8425** so the xInit method need not be threadsafe. ^The 8426** xShutdown method is only called from [sqlite3_shutdown()] so it does 8427** not need to be threadsafe either. All other methods must be threadsafe 8428** in multithreaded applications. 8429** 8430** ^SQLite will never invoke xInit() more than once without an intervening 8431** call to xShutdown(). 8432** 8433** [[the xCreate() page cache methods]] 8434** ^SQLite invokes the xCreate() method to construct a new cache instance. 8435** SQLite will typically create one cache instance for each open database file, 8436** though this is not guaranteed. ^The 8437** first parameter, szPage, is the size in bytes of the pages that must 8438** be allocated by the cache. ^szPage will always a power of two. ^The 8439** second parameter szExtra is a number of bytes of extra storage 8440** associated with each page cache entry. ^The szExtra parameter will 8441** a number less than 250. SQLite will use the 8442** extra szExtra bytes on each page to store metadata about the underlying 8443** database page on disk. The value passed into szExtra depends 8444** on the SQLite version, the target platform, and how SQLite was compiled. 8445** ^The third argument to xCreate(), bPurgeable, is true if the cache being 8446** created will be used to cache database pages of a file stored on disk, or 8447** false if it is used for an in-memory database. The cache implementation 8448** does not have to do anything special based with the value of bPurgeable; 8449** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 8450** never invoke xUnpin() except to deliberately delete a page. 8451** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 8452** false will always have the "discard" flag set to true. 8453** ^Hence, a cache created with bPurgeable false will 8454** never contain any unpinned pages. 8455** 8456** [[the xCachesize() page cache method]] 8457** ^(The xCachesize() method may be called at any time by SQLite to set the 8458** suggested maximum cache-size (number of pages stored by) the cache 8459** instance passed as the first argument. This is the value configured using 8460** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 8461** parameter, the implementation is not required to do anything with this 8462** value; it is advisory only. 8463** 8464** [[the xPagecount() page cache methods]] 8465** The xPagecount() method must return the number of pages currently 8466** stored in the cache, both pinned and unpinned. 8467** 8468** [[the xFetch() page cache methods]] 8469** The xFetch() method locates a page in the cache and returns a pointer to 8470** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 8471** The pBuf element of the returned sqlite3_pcache_page object will be a 8472** pointer to a buffer of szPage bytes used to store the content of a 8473** single database page. The pExtra element of sqlite3_pcache_page will be 8474** a pointer to the szExtra bytes of extra storage that SQLite has requested 8475** for each entry in the page cache. 8476** 8477** The page to be fetched is determined by the key. ^The minimum key value 8478** is 1. After it has been retrieved using xFetch, the page is considered 8479** to be "pinned". 8480** 8481** If the requested page is already in the page cache, then the page cache 8482** implementation must return a pointer to the page buffer with its content 8483** intact. If the requested page is not already in the cache, then the 8484** cache implementation should use the value of the createFlag 8485** parameter to help it determined what action to take: 8486** 8487** <table border=1 width=85% align=center> 8488** <tr><th> createFlag <th> Behavior when page is not already in cache 8489** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 8490** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 8491** Otherwise return NULL. 8492** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 8493** NULL if allocating a new page is effectively impossible. 8494** </table> 8495** 8496** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 8497** will only use a createFlag of 2 after a prior call with a createFlag of 1 8498** failed.)^ In between the xFetch() calls, SQLite may 8499** attempt to unpin one or more cache pages by spilling the content of 8500** pinned pages to disk and synching the operating system disk cache. 8501** 8502** [[the xUnpin() page cache method]] 8503** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 8504** as its second argument. If the third parameter, discard, is non-zero, 8505** then the page must be evicted from the cache. 8506** ^If the discard parameter is 8507** zero, then the page may be discarded or retained at the discretion of 8508** page cache implementation. ^The page cache implementation 8509** may choose to evict unpinned pages at any time. 8510** 8511** The cache must not perform any reference counting. A single 8512** call to xUnpin() unpins the page regardless of the number of prior calls 8513** to xFetch(). 8514** 8515** [[the xRekey() page cache methods]] 8516** The xRekey() method is used to change the key value associated with the 8517** page passed as the second argument. If the cache 8518** previously contains an entry associated with newKey, it must be 8519** discarded. ^Any prior cache entry associated with newKey is guaranteed not 8520** to be pinned. 8521** 8522** When SQLite calls the xTruncate() method, the cache must discard all 8523** existing cache entries with page numbers (keys) greater than or equal 8524** to the value of the iLimit parameter passed to xTruncate(). If any 8525** of these pages are pinned, they are implicitly unpinned, meaning that 8526** they can be safely discarded. 8527** 8528** [[the xDestroy() page cache method]] 8529** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 8530** All resources associated with the specified cache should be freed. ^After 8531** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 8532** handle invalid, and will not use it with any other sqlite3_pcache_methods2 8533** functions. 8534** 8535** [[the xShrink() page cache method]] 8536** ^SQLite invokes the xShrink() method when it wants the page cache to 8537** free up as much of heap memory as possible. The page cache implementation 8538** is not obligated to free any memory, but well-behaved implementations should 8539** do their best. 8540*/ 8541typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 8542struct sqlite3_pcache_methods2 { 8543 int iVersion; 8544 void *pArg; 8545 int (*xInit)(void*); 8546 void (*xShutdown)(void*); 8547 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 8548 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8549 int (*xPagecount)(sqlite3_pcache*); 8550 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8551 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 8552 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 8553 unsigned oldKey, unsigned newKey); 8554 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8555 void (*xDestroy)(sqlite3_pcache*); 8556 void (*xShrink)(sqlite3_pcache*); 8557}; 8558 8559/* 8560** This is the obsolete pcache_methods object that has now been replaced 8561** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 8562** retained in the header file for backwards compatibility only. 8563*/ 8564typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 8565struct sqlite3_pcache_methods { 8566 void *pArg; 8567 int (*xInit)(void*); 8568 void (*xShutdown)(void*); 8569 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 8570 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8571 int (*xPagecount)(sqlite3_pcache*); 8572 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8573 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 8574 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 8575 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8576 void (*xDestroy)(sqlite3_pcache*); 8577}; 8578 8579 8580/* 8581** CAPI3REF: Online Backup Object 8582** 8583** The sqlite3_backup object records state information about an ongoing 8584** online backup operation. ^The sqlite3_backup object is created by 8585** a call to [sqlite3_backup_init()] and is destroyed by a call to 8586** [sqlite3_backup_finish()]. 8587** 8588** See Also: [Using the SQLite Online Backup API] 8589*/ 8590typedef struct sqlite3_backup sqlite3_backup; 8591 8592/* 8593** CAPI3REF: Online Backup API. 8594** 8595** The backup API copies the content of one database into another. 8596** It is useful either for creating backups of databases or 8597** for copying in-memory databases to or from persistent files. 8598** 8599** See Also: [Using the SQLite Online Backup API] 8600** 8601** ^SQLite holds a write transaction open on the destination database file 8602** for the duration of the backup operation. 8603** ^The source database is read-locked only while it is being read; 8604** it is not locked continuously for the entire backup operation. 8605** ^Thus, the backup may be performed on a live source database without 8606** preventing other database connections from 8607** reading or writing to the source database while the backup is underway. 8608** 8609** ^(To perform a backup operation: 8610** <ol> 8611** <li><b>sqlite3_backup_init()</b> is called once to initialize the 8612** backup, 8613** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 8614** the data between the two databases, and finally 8615** <li><b>sqlite3_backup_finish()</b> is called to release all resources 8616** associated with the backup operation. 8617** </ol>)^ 8618** There should be exactly one call to sqlite3_backup_finish() for each 8619** successful call to sqlite3_backup_init(). 8620** 8621** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 8622** 8623** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 8624** [database connection] associated with the destination database 8625** and the database name, respectively. 8626** ^The database name is "main" for the main database, "temp" for the 8627** temporary database, or the name specified after the AS keyword in 8628** an [ATTACH] statement for an attached database. 8629** ^The S and M arguments passed to 8630** sqlite3_backup_init(D,N,S,M) identify the [database connection] 8631** and database name of the source database, respectively. 8632** ^The source and destination [database connections] (parameters S and D) 8633** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 8634** an error. 8635** 8636** ^A call to sqlite3_backup_init() will fail, returning NULL, if 8637** there is already a read or read-write transaction open on the 8638** destination database. 8639** 8640** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 8641** returned and an error code and error message are stored in the 8642** destination [database connection] D. 8643** ^The error code and message for the failed call to sqlite3_backup_init() 8644** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 8645** [sqlite3_errmsg16()] functions. 8646** ^A successful call to sqlite3_backup_init() returns a pointer to an 8647** [sqlite3_backup] object. 8648** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 8649** sqlite3_backup_finish() functions to perform the specified backup 8650** operation. 8651** 8652** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 8653** 8654** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 8655** the source and destination databases specified by [sqlite3_backup] object B. 8656** ^If N is negative, all remaining source pages are copied. 8657** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 8658** are still more pages to be copied, then the function returns [SQLITE_OK]. 8659** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 8660** from source to destination, then it returns [SQLITE_DONE]. 8661** ^If an error occurs while running sqlite3_backup_step(B,N), 8662** then an [error code] is returned. ^As well as [SQLITE_OK] and 8663** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 8664** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 8665** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 8666** 8667** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 8668** <ol> 8669** <li> the destination database was opened read-only, or 8670** <li> the destination database is using write-ahead-log journaling 8671** and the destination and source page sizes differ, or 8672** <li> the destination database is an in-memory database and the 8673** destination and source page sizes differ. 8674** </ol>)^ 8675** 8676** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 8677** the [sqlite3_busy_handler | busy-handler function] 8678** is invoked (if one is specified). ^If the 8679** busy-handler returns non-zero before the lock is available, then 8680** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 8681** sqlite3_backup_step() can be retried later. ^If the source 8682** [database connection] 8683** is being used to write to the source database when sqlite3_backup_step() 8684** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 8685** case the call to sqlite3_backup_step() can be retried later on. ^(If 8686** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 8687** [SQLITE_READONLY] is returned, then 8688** there is no point in retrying the call to sqlite3_backup_step(). These 8689** errors are considered fatal.)^ The application must accept 8690** that the backup operation has failed and pass the backup operation handle 8691** to the sqlite3_backup_finish() to release associated resources. 8692** 8693** ^The first call to sqlite3_backup_step() obtains an exclusive lock 8694** on the destination file. ^The exclusive lock is not released until either 8695** sqlite3_backup_finish() is called or the backup operation is complete 8696** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 8697** sqlite3_backup_step() obtains a [shared lock] on the source database that 8698** lasts for the duration of the sqlite3_backup_step() call. 8699** ^Because the source database is not locked between calls to 8700** sqlite3_backup_step(), the source database may be modified mid-way 8701** through the backup process. ^If the source database is modified by an 8702** external process or via a database connection other than the one being 8703** used by the backup operation, then the backup will be automatically 8704** restarted by the next call to sqlite3_backup_step(). ^If the source 8705** database is modified by the using the same database connection as is used 8706** by the backup operation, then the backup database is automatically 8707** updated at the same time. 8708** 8709** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 8710** 8711** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 8712** application wishes to abandon the backup operation, the application 8713** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 8714** ^The sqlite3_backup_finish() interfaces releases all 8715** resources associated with the [sqlite3_backup] object. 8716** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 8717** active write-transaction on the destination database is rolled back. 8718** The [sqlite3_backup] object is invalid 8719** and may not be used following a call to sqlite3_backup_finish(). 8720** 8721** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 8722** sqlite3_backup_step() errors occurred, regardless or whether or not 8723** sqlite3_backup_step() completed. 8724** ^If an out-of-memory condition or IO error occurred during any prior 8725** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 8726** sqlite3_backup_finish() returns the corresponding [error code]. 8727** 8728** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 8729** is not a permanent error and does not affect the return value of 8730** sqlite3_backup_finish(). 8731** 8732** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 8733** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 8734** 8735** ^The sqlite3_backup_remaining() routine returns the number of pages still 8736** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 8737** ^The sqlite3_backup_pagecount() routine returns the total number of pages 8738** in the source database at the conclusion of the most recent 8739** sqlite3_backup_step(). 8740** ^(The values returned by these functions are only updated by 8741** sqlite3_backup_step(). If the source database is modified in a way that 8742** changes the size of the source database or the number of pages remaining, 8743** those changes are not reflected in the output of sqlite3_backup_pagecount() 8744** and sqlite3_backup_remaining() until after the next 8745** sqlite3_backup_step().)^ 8746** 8747** <b>Concurrent Usage of Database Handles</b> 8748** 8749** ^The source [database connection] may be used by the application for other 8750** purposes while a backup operation is underway or being initialized. 8751** ^If SQLite is compiled and configured to support threadsafe database 8752** connections, then the source database connection may be used concurrently 8753** from within other threads. 8754** 8755** However, the application must guarantee that the destination 8756** [database connection] is not passed to any other API (by any thread) after 8757** sqlite3_backup_init() is called and before the corresponding call to 8758** sqlite3_backup_finish(). SQLite does not currently check to see 8759** if the application incorrectly accesses the destination [database connection] 8760** and so no error code is reported, but the operations may malfunction 8761** nevertheless. Use of the destination database connection while a 8762** backup is in progress might also also cause a mutex deadlock. 8763** 8764** If running in [shared cache mode], the application must 8765** guarantee that the shared cache used by the destination database 8766** is not accessed while the backup is running. In practice this means 8767** that the application must guarantee that the disk file being 8768** backed up to is not accessed by any connection within the process, 8769** not just the specific connection that was passed to sqlite3_backup_init(). 8770** 8771** The [sqlite3_backup] object itself is partially threadsafe. Multiple 8772** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 8773** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 8774** APIs are not strictly speaking threadsafe. If they are invoked at the 8775** same time as another thread is invoking sqlite3_backup_step() it is 8776** possible that they return invalid values. 8777*/ 8778sqlite3_backup *sqlite3_backup_init( 8779 sqlite3 *pDest, /* Destination database handle */ 8780 const char *zDestName, /* Destination database name */ 8781 sqlite3 *pSource, /* Source database handle */ 8782 const char *zSourceName /* Source database name */ 8783); 8784int sqlite3_backup_step(sqlite3_backup *p, int nPage); 8785int sqlite3_backup_finish(sqlite3_backup *p); 8786int sqlite3_backup_remaining(sqlite3_backup *p); 8787int sqlite3_backup_pagecount(sqlite3_backup *p); 8788 8789/* 8790** CAPI3REF: Unlock Notification 8791** METHOD: sqlite3 8792** 8793** ^When running in shared-cache mode, a database operation may fail with 8794** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 8795** individual tables within the shared-cache cannot be obtained. See 8796** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 8797** ^This API may be used to register a callback that SQLite will invoke 8798** when the connection currently holding the required lock relinquishes it. 8799** ^This API is only available if the library was compiled with the 8800** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 8801** 8802** See Also: [Using the SQLite Unlock Notification Feature]. 8803** 8804** ^Shared-cache locks are released when a database connection concludes 8805** its current transaction, either by committing it or rolling it back. 8806** 8807** ^When a connection (known as the blocked connection) fails to obtain a 8808** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 8809** identity of the database connection (the blocking connection) that 8810** has locked the required resource is stored internally. ^After an 8811** application receives an SQLITE_LOCKED error, it may call the 8812** sqlite3_unlock_notify() method with the blocked connection handle as 8813** the first argument to register for a callback that will be invoked 8814** when the blocking connections current transaction is concluded. ^The 8815** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 8816** call that concludes the blocking connection's transaction. 8817** 8818** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 8819** there is a chance that the blocking connection will have already 8820** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 8821** If this happens, then the specified callback is invoked immediately, 8822** from within the call to sqlite3_unlock_notify().)^ 8823** 8824** ^If the blocked connection is attempting to obtain a write-lock on a 8825** shared-cache table, and more than one other connection currently holds 8826** a read-lock on the same table, then SQLite arbitrarily selects one of 8827** the other connections to use as the blocking connection. 8828** 8829** ^(There may be at most one unlock-notify callback registered by a 8830** blocked connection. If sqlite3_unlock_notify() is called when the 8831** blocked connection already has a registered unlock-notify callback, 8832** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 8833** called with a NULL pointer as its second argument, then any existing 8834** unlock-notify callback is canceled. ^The blocked connections 8835** unlock-notify callback may also be canceled by closing the blocked 8836** connection using [sqlite3_close()]. 8837** 8838** The unlock-notify callback is not reentrant. If an application invokes 8839** any sqlite3_xxx API functions from within an unlock-notify callback, a 8840** crash or deadlock may be the result. 8841** 8842** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 8843** returns SQLITE_OK. 8844** 8845** <b>Callback Invocation Details</b> 8846** 8847** When an unlock-notify callback is registered, the application provides a 8848** single void* pointer that is passed to the callback when it is invoked. 8849** However, the signature of the callback function allows SQLite to pass 8850** it an array of void* context pointers. The first argument passed to 8851** an unlock-notify callback is a pointer to an array of void* pointers, 8852** and the second is the number of entries in the array. 8853** 8854** When a blocking connection's transaction is concluded, there may be 8855** more than one blocked connection that has registered for an unlock-notify 8856** callback. ^If two or more such blocked connections have specified the 8857** same callback function, then instead of invoking the callback function 8858** multiple times, it is invoked once with the set of void* context pointers 8859** specified by the blocked connections bundled together into an array. 8860** This gives the application an opportunity to prioritize any actions 8861** related to the set of unblocked database connections. 8862** 8863** <b>Deadlock Detection</b> 8864** 8865** Assuming that after registering for an unlock-notify callback a 8866** database waits for the callback to be issued before taking any further 8867** action (a reasonable assumption), then using this API may cause the 8868** application to deadlock. For example, if connection X is waiting for 8869** connection Y's transaction to be concluded, and similarly connection 8870** Y is waiting on connection X's transaction, then neither connection 8871** will proceed and the system may remain deadlocked indefinitely. 8872** 8873** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 8874** detection. ^If a given call to sqlite3_unlock_notify() would put the 8875** system in a deadlocked state, then SQLITE_LOCKED is returned and no 8876** unlock-notify callback is registered. The system is said to be in 8877** a deadlocked state if connection A has registered for an unlock-notify 8878** callback on the conclusion of connection B's transaction, and connection 8879** B has itself registered for an unlock-notify callback when connection 8880** A's transaction is concluded. ^Indirect deadlock is also detected, so 8881** the system is also considered to be deadlocked if connection B has 8882** registered for an unlock-notify callback on the conclusion of connection 8883** C's transaction, where connection C is waiting on connection A. ^Any 8884** number of levels of indirection are allowed. 8885** 8886** <b>The "DROP TABLE" Exception</b> 8887** 8888** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 8889** always appropriate to call sqlite3_unlock_notify(). There is however, 8890** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 8891** SQLite checks if there are any currently executing SELECT statements 8892** that belong to the same connection. If there are, SQLITE_LOCKED is 8893** returned. In this case there is no "blocking connection", so invoking 8894** sqlite3_unlock_notify() results in the unlock-notify callback being 8895** invoked immediately. If the application then re-attempts the "DROP TABLE" 8896** or "DROP INDEX" query, an infinite loop might be the result. 8897** 8898** One way around this problem is to check the extended error code returned 8899** by an sqlite3_step() call. ^(If there is a blocking connection, then the 8900** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 8901** the special "DROP TABLE/INDEX" case, the extended error code is just 8902** SQLITE_LOCKED.)^ 8903*/ 8904int sqlite3_unlock_notify( 8905 sqlite3 *pBlocked, /* Waiting connection */ 8906 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 8907 void *pNotifyArg /* Argument to pass to xNotify */ 8908); 8909 8910 8911/* 8912** CAPI3REF: String Comparison 8913** 8914** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 8915** and extensions to compare the contents of two buffers containing UTF-8 8916** strings in a case-independent fashion, using the same definition of "case 8917** independence" that SQLite uses internally when comparing identifiers. 8918*/ 8919int sqlite3_stricmp(const char *, const char *); 8920int sqlite3_strnicmp(const char *, const char *, int); 8921 8922/* 8923** CAPI3REF: String Globbing 8924* 8925** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 8926** string X matches the [GLOB] pattern P. 8927** ^The definition of [GLOB] pattern matching used in 8928** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 8929** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 8930** is case sensitive. 8931** 8932** Note that this routine returns zero on a match and non-zero if the strings 8933** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8934** 8935** See also: [sqlite3_strlike()]. 8936*/ 8937int sqlite3_strglob(const char *zGlob, const char *zStr); 8938 8939/* 8940** CAPI3REF: String LIKE Matching 8941* 8942** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 8943** string X matches the [LIKE] pattern P with escape character E. 8944** ^The definition of [LIKE] pattern matching used in 8945** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 8946** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 8947** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 8948** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 8949** insensitive - equivalent upper and lower case ASCII characters match 8950** one another. 8951** 8952** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 8953** only ASCII characters are case folded. 8954** 8955** Note that this routine returns zero on a match and non-zero if the strings 8956** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8957** 8958** See also: [sqlite3_strglob()]. 8959*/ 8960int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8961 8962/* 8963** CAPI3REF: Error Logging Interface 8964** 8965** ^The [sqlite3_log()] interface writes a message into the [error log] 8966** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8967** ^If logging is enabled, the zFormat string and subsequent arguments are 8968** used with [sqlite3_snprintf()] to generate the final output string. 8969** 8970** The sqlite3_log() interface is intended for use by extensions such as 8971** virtual tables, collating functions, and SQL functions. While there is 8972** nothing to prevent an application from calling sqlite3_log(), doing so 8973** is considered bad form. 8974** 8975** The zFormat string must not be NULL. 8976** 8977** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8978** will not use dynamically allocated memory. The log message is stored in 8979** a fixed-length buffer on the stack. If the log message is longer than 8980** a few hundred characters, it will be truncated to the length of the 8981** buffer. 8982*/ 8983void sqlite3_log(int iErrCode, const char *zFormat, ...); 8984 8985/* 8986** CAPI3REF: Write-Ahead Log Commit Hook 8987** METHOD: sqlite3 8988** 8989** ^The [sqlite3_wal_hook()] function is used to register a callback that 8990** is invoked each time data is committed to a database in wal mode. 8991** 8992** ^(The callback is invoked by SQLite after the commit has taken place and 8993** the associated write-lock on the database released)^, so the implementation 8994** may read, write or [checkpoint] the database as required. 8995** 8996** ^The first parameter passed to the callback function when it is invoked 8997** is a copy of the third parameter passed to sqlite3_wal_hook() when 8998** registering the callback. ^The second is a copy of the database handle. 8999** ^The third parameter is the name of the database that was written to - 9000** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 9001** is the number of pages currently in the write-ahead log file, 9002** including those that were just committed. 9003** 9004** The callback function should normally return [SQLITE_OK]. ^If an error 9005** code is returned, that error will propagate back up through the 9006** SQLite code base to cause the statement that provoked the callback 9007** to report an error, though the commit will have still occurred. If the 9008** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 9009** that does not correspond to any valid SQLite error code, the results 9010** are undefined. 9011** 9012** A single database handle may have at most a single write-ahead log callback 9013** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 9014** previously registered write-ahead log callback. ^Note that the 9015** [sqlite3_wal_autocheckpoint()] interface and the 9016** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 9017** overwrite any prior [sqlite3_wal_hook()] settings. 9018*/ 9019void *sqlite3_wal_hook( 9020 sqlite3*, 9021 int(*)(void *,sqlite3*,const char*,int), 9022 void* 9023); 9024 9025/* 9026** CAPI3REF: Configure an auto-checkpoint 9027** METHOD: sqlite3 9028** 9029** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 9030** [sqlite3_wal_hook()] that causes any database on [database connection] D 9031** to automatically [checkpoint] 9032** after committing a transaction if there are N or 9033** more frames in the [write-ahead log] file. ^Passing zero or 9034** a negative value as the nFrame parameter disables automatic 9035** checkpoints entirely. 9036** 9037** ^The callback registered by this function replaces any existing callback 9038** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 9039** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 9040** configured by this function. 9041** 9042** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 9043** from SQL. 9044** 9045** ^Checkpoints initiated by this mechanism are 9046** [sqlite3_wal_checkpoint_v2|PASSIVE]. 9047** 9048** ^Every new [database connection] defaults to having the auto-checkpoint 9049** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 9050** pages. The use of this interface 9051** is only necessary if the default setting is found to be suboptimal 9052** for a particular application. 9053*/ 9054int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 9055 9056/* 9057** CAPI3REF: Checkpoint a database 9058** METHOD: sqlite3 9059** 9060** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 9061** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 9062** 9063** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 9064** [write-ahead log] for database X on [database connection] D to be 9065** transferred into the database file and for the write-ahead log to 9066** be reset. See the [checkpointing] documentation for addition 9067** information. 9068** 9069** This interface used to be the only way to cause a checkpoint to 9070** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 9071** interface was added. This interface is retained for backwards 9072** compatibility and as a convenience for applications that need to manually 9073** start a callback but which do not need the full power (and corresponding 9074** complication) of [sqlite3_wal_checkpoint_v2()]. 9075*/ 9076int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 9077 9078/* 9079** CAPI3REF: Checkpoint a database 9080** METHOD: sqlite3 9081** 9082** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 9083** operation on database X of [database connection] D in mode M. Status 9084** information is written back into integers pointed to by L and C.)^ 9085** ^(The M parameter must be a valid [checkpoint mode]:)^ 9086** 9087** <dl> 9088** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 9089** ^Checkpoint as many frames as possible without waiting for any database 9090** readers or writers to finish, then sync the database file if all frames 9091** in the log were checkpointed. ^The [busy-handler callback] 9092** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 9093** ^On the other hand, passive mode might leave the checkpoint unfinished 9094** if there are concurrent readers or writers. 9095** 9096** <dt>SQLITE_CHECKPOINT_FULL<dd> 9097** ^This mode blocks (it invokes the 9098** [sqlite3_busy_handler|busy-handler callback]) until there is no 9099** database writer and all readers are reading from the most recent database 9100** snapshot. ^It then checkpoints all frames in the log file and syncs the 9101** database file. ^This mode blocks new database writers while it is pending, 9102** but new database readers are allowed to continue unimpeded. 9103** 9104** <dt>SQLITE_CHECKPOINT_RESTART<dd> 9105** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 9106** that after checkpointing the log file it blocks (calls the 9107** [busy-handler callback]) 9108** until all readers are reading from the database file only. ^This ensures 9109** that the next writer will restart the log file from the beginning. 9110** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 9111** database writer attempts while it is pending, but does not impede readers. 9112** 9113** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 9114** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 9115** addition that it also truncates the log file to zero bytes just prior 9116** to a successful return. 9117** </dl> 9118** 9119** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 9120** the log file or to -1 if the checkpoint could not run because 9121** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 9122** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 9123** log file (including any that were already checkpointed before the function 9124** was called) or to -1 if the checkpoint could not run due to an error or 9125** because the database is not in WAL mode. ^Note that upon successful 9126** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 9127** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 9128** 9129** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 9130** any other process is running a checkpoint operation at the same time, the 9131** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 9132** busy-handler configured, it will not be invoked in this case. 9133** 9134** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 9135** exclusive "writer" lock on the database file. ^If the writer lock cannot be 9136** obtained immediately, and a busy-handler is configured, it is invoked and 9137** the writer lock retried until either the busy-handler returns 0 or the lock 9138** is successfully obtained. ^The busy-handler is also invoked while waiting for 9139** database readers as described above. ^If the busy-handler returns 0 before 9140** the writer lock is obtained or while waiting for database readers, the 9141** checkpoint operation proceeds from that point in the same way as 9142** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 9143** without blocking any further. ^SQLITE_BUSY is returned in this case. 9144** 9145** ^If parameter zDb is NULL or points to a zero length string, then the 9146** specified operation is attempted on all WAL databases [attached] to 9147** [database connection] db. In this case the 9148** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 9149** an SQLITE_BUSY error is encountered when processing one or more of the 9150** attached WAL databases, the operation is still attempted on any remaining 9151** attached databases and SQLITE_BUSY is returned at the end. ^If any other 9152** error occurs while processing an attached database, processing is abandoned 9153** and the error code is returned to the caller immediately. ^If no error 9154** (SQLITE_BUSY or otherwise) is encountered while processing the attached 9155** databases, SQLITE_OK is returned. 9156** 9157** ^If database zDb is the name of an attached database that is not in WAL 9158** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 9159** zDb is not NULL (or a zero length string) and is not the name of any 9160** attached database, SQLITE_ERROR is returned to the caller. 9161** 9162** ^Unless it returns SQLITE_MISUSE, 9163** the sqlite3_wal_checkpoint_v2() interface 9164** sets the error information that is queried by 9165** [sqlite3_errcode()] and [sqlite3_errmsg()]. 9166** 9167** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 9168** from SQL. 9169*/ 9170int sqlite3_wal_checkpoint_v2( 9171 sqlite3 *db, /* Database handle */ 9172 const char *zDb, /* Name of attached database (or NULL) */ 9173 int eMode, /* SQLITE_CHECKPOINT_* value */ 9174 int *pnLog, /* OUT: Size of WAL log in frames */ 9175 int *pnCkpt /* OUT: Total number of frames checkpointed */ 9176); 9177 9178/* 9179** CAPI3REF: Checkpoint Mode Values 9180** KEYWORDS: {checkpoint mode} 9181** 9182** These constants define all valid values for the "checkpoint mode" passed 9183** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 9184** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 9185** meaning of each of these checkpoint modes. 9186*/ 9187#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 9188#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 9189#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 9190#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 9191 9192/* 9193** CAPI3REF: Virtual Table Interface Configuration 9194** 9195** This function may be called by either the [xConnect] or [xCreate] method 9196** of a [virtual table] implementation to configure 9197** various facets of the virtual table interface. 9198** 9199** If this interface is invoked outside the context of an xConnect or 9200** xCreate virtual table method then the behavior is undefined. 9201** 9202** In the call sqlite3_vtab_config(D,C,...) the D parameter is the 9203** [database connection] in which the virtual table is being created and 9204** which is passed in as the first argument to the [xConnect] or [xCreate] 9205** method that is invoking sqlite3_vtab_config(). The C parameter is one 9206** of the [virtual table configuration options]. The presence and meaning 9207** of parameters after C depend on which [virtual table configuration option] 9208** is used. 9209*/ 9210int sqlite3_vtab_config(sqlite3*, int op, ...); 9211 9212/* 9213** CAPI3REF: Virtual Table Configuration Options 9214** KEYWORDS: {virtual table configuration options} 9215** KEYWORDS: {virtual table configuration option} 9216** 9217** These macros define the various options to the 9218** [sqlite3_vtab_config()] interface that [virtual table] implementations 9219** can use to customize and optimize their behavior. 9220** 9221** <dl> 9222** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]] 9223** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt> 9224** <dd>Calls of the form 9225** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 9226** where X is an integer. If X is zero, then the [virtual table] whose 9227** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 9228** support constraints. In this configuration (which is the default) if 9229** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 9230** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 9231** specified as part of the users SQL statement, regardless of the actual 9232** ON CONFLICT mode specified. 9233** 9234** If X is non-zero, then the virtual table implementation guarantees 9235** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 9236** any modifications to internal or persistent data structures have been made. 9237** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 9238** is able to roll back a statement or database transaction, and abandon 9239** or continue processing the current SQL statement as appropriate. 9240** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 9241** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 9242** had been ABORT. 9243** 9244** Virtual table implementations that are required to handle OR REPLACE 9245** must do so within the [xUpdate] method. If a call to the 9246** [sqlite3_vtab_on_conflict()] function indicates that the current ON 9247** CONFLICT policy is REPLACE, the virtual table implementation should 9248** silently replace the appropriate rows within the xUpdate callback and 9249** return SQLITE_OK. Or, if this is not possible, it may return 9250** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 9251** constraint handling. 9252** </dd> 9253** 9254** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt> 9255** <dd>Calls of the form 9256** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the 9257** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9258** prohibits that virtual table from being used from within triggers and 9259** views. 9260** </dd> 9261** 9262** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt> 9263** <dd>Calls of the form 9264** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the 9265** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9266** identify that virtual table as being safe to use from within triggers 9267** and views. Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the 9268** virtual table can do no serious harm even if it is controlled by a 9269** malicious hacker. Developers should avoid setting the SQLITE_VTAB_INNOCUOUS 9270** flag unless absolutely necessary. 9271** </dd> 9272** </dl> 9273*/ 9274#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 9275#define SQLITE_VTAB_INNOCUOUS 2 9276#define SQLITE_VTAB_DIRECTONLY 3 9277 9278/* 9279** CAPI3REF: Determine The Virtual Table Conflict Policy 9280** 9281** This function may only be called from within a call to the [xUpdate] method 9282** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 9283** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 9284** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 9285** of the SQL statement that triggered the call to the [xUpdate] method of the 9286** [virtual table]. 9287*/ 9288int sqlite3_vtab_on_conflict(sqlite3 *); 9289 9290/* 9291** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 9292** 9293** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 9294** method of a [virtual table], then it might return true if the 9295** column is being fetched as part of an UPDATE operation during which the 9296** column value will not change. The virtual table implementation can use 9297** this hint as permission to substitute a return value that is less 9298** expensive to compute and that the corresponding 9299** [xUpdate] method understands as a "no-change" value. 9300** 9301** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 9302** the column is not changed by the UPDATE statement, then the xColumn 9303** method can optionally return without setting a result, without calling 9304** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 9305** In that case, [sqlite3_value_nochange(X)] will return true for the 9306** same column in the [xUpdate] method. 9307** 9308** The sqlite3_vtab_nochange() routine is an optimization. Virtual table 9309** implementations should continue to give a correct answer even if the 9310** sqlite3_vtab_nochange() interface were to always return false. In the 9311** current implementation, the sqlite3_vtab_nochange() interface does always 9312** returns false for the enhanced [UPDATE FROM] statement. 9313*/ 9314int sqlite3_vtab_nochange(sqlite3_context*); 9315 9316/* 9317** CAPI3REF: Determine The Collation For a Virtual Table Constraint 9318** 9319** This function may only be called from within a call to the [xBestIndex] 9320** method of a [virtual table]. 9321** 9322** The first argument must be the sqlite3_index_info object that is the 9323** first parameter to the xBestIndex() method. The second argument must be 9324** an index into the aConstraint[] array belonging to the sqlite3_index_info 9325** structure passed to xBestIndex. This function returns a pointer to a buffer 9326** containing the name of the collation sequence for the corresponding 9327** constraint. 9328*/ 9329SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 9330 9331/* 9332** CAPI3REF: Conflict resolution modes 9333** KEYWORDS: {conflict resolution mode} 9334** 9335** These constants are returned by [sqlite3_vtab_on_conflict()] to 9336** inform a [virtual table] implementation what the [ON CONFLICT] mode 9337** is for the SQL statement being evaluated. 9338** 9339** Note that the [SQLITE_IGNORE] constant is also used as a potential 9340** return value from the [sqlite3_set_authorizer()] callback and that 9341** [SQLITE_ABORT] is also a [result code]. 9342*/ 9343#define SQLITE_ROLLBACK 1 9344/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 9345#define SQLITE_FAIL 3 9346/* #define SQLITE_ABORT 4 // Also an error code */ 9347#define SQLITE_REPLACE 5 9348 9349/* 9350** CAPI3REF: Prepared Statement Scan Status Opcodes 9351** KEYWORDS: {scanstatus options} 9352** 9353** The following constants can be used for the T parameter to the 9354** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 9355** different metric for sqlite3_stmt_scanstatus() to return. 9356** 9357** When the value returned to V is a string, space to hold that string is 9358** managed by the prepared statement S and will be automatically freed when 9359** S is finalized. 9360** 9361** <dl> 9362** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 9363** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be 9364** set to the total number of times that the X-th loop has run.</dd> 9365** 9366** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 9367** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set 9368** to the total number of rows examined by all iterations of the X-th loop.</dd> 9369** 9370** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 9371** <dd>^The "double" variable pointed to by the V parameter will be set to the 9372** query planner's estimate for the average number of rows output from each 9373** iteration of the X-th loop. If the query planner's estimates was accurate, 9374** then this value will approximate the quotient NVISIT/NLOOP and the 9375** product of this value for all prior loops with the same SELECTID will 9376** be the NLOOP value for the current loop. 9377** 9378** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 9379** <dd>^The "const char *" variable pointed to by the V parameter will be set 9380** to a zero-terminated UTF-8 string containing the name of the index or table 9381** used for the X-th loop. 9382** 9383** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 9384** <dd>^The "const char *" variable pointed to by the V parameter will be set 9385** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 9386** description for the X-th loop. 9387** 9388** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 9389** <dd>^The "int" variable pointed to by the V parameter will be set to the 9390** "select-id" for the X-th loop. The select-id identifies which query or 9391** subquery the loop is part of. The main query has a select-id of zero. 9392** The select-id is the same value as is output in the first column 9393** of an [EXPLAIN QUERY PLAN] query. 9394** </dl> 9395*/ 9396#define SQLITE_SCANSTAT_NLOOP 0 9397#define SQLITE_SCANSTAT_NVISIT 1 9398#define SQLITE_SCANSTAT_EST 2 9399#define SQLITE_SCANSTAT_NAME 3 9400#define SQLITE_SCANSTAT_EXPLAIN 4 9401#define SQLITE_SCANSTAT_SELECTID 5 9402 9403/* 9404** CAPI3REF: Prepared Statement Scan Status 9405** METHOD: sqlite3_stmt 9406** 9407** This interface returns information about the predicted and measured 9408** performance for pStmt. Advanced applications can use this 9409** interface to compare the predicted and the measured performance and 9410** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 9411** 9412** Since this interface is expected to be rarely used, it is only 9413** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 9414** compile-time option. 9415** 9416** The "iScanStatusOp" parameter determines which status information to return. 9417** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 9418** of this interface is undefined. 9419** ^The requested measurement is written into a variable pointed to by 9420** the "pOut" parameter. 9421** Parameter "idx" identifies the specific loop to retrieve statistics for. 9422** Loops are numbered starting from zero. ^If idx is out of range - less than 9423** zero or greater than or equal to the total number of loops used to implement 9424** the statement - a non-zero value is returned and the variable that pOut 9425** points to is unchanged. 9426** 9427** ^Statistics might not be available for all loops in all statements. ^In cases 9428** where there exist loops with no available statistics, this function behaves 9429** as if the loop did not exist - it returns non-zero and leave the variable 9430** that pOut points to unchanged. 9431** 9432** See also: [sqlite3_stmt_scanstatus_reset()] 9433*/ 9434int sqlite3_stmt_scanstatus( 9435 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 9436 int idx, /* Index of loop to report on */ 9437 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 9438 void *pOut /* Result written here */ 9439); 9440 9441/* 9442** CAPI3REF: Zero Scan-Status Counters 9443** METHOD: sqlite3_stmt 9444** 9445** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 9446** 9447** This API is only available if the library is built with pre-processor 9448** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 9449*/ 9450void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 9451 9452/* 9453** CAPI3REF: Flush caches to disk mid-transaction 9454** METHOD: sqlite3 9455** 9456** ^If a write-transaction is open on [database connection] D when the 9457** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 9458** pages in the pager-cache that are not currently in use are written out 9459** to disk. A dirty page may be in use if a database cursor created by an 9460** active SQL statement is reading from it, or if it is page 1 of a database 9461** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 9462** interface flushes caches for all schemas - "main", "temp", and 9463** any [attached] databases. 9464** 9465** ^If this function needs to obtain extra database locks before dirty pages 9466** can be flushed to disk, it does so. ^If those locks cannot be obtained 9467** immediately and there is a busy-handler callback configured, it is invoked 9468** in the usual manner. ^If the required lock still cannot be obtained, then 9469** the database is skipped and an attempt made to flush any dirty pages 9470** belonging to the next (if any) database. ^If any databases are skipped 9471** because locks cannot be obtained, but no other error occurs, this 9472** function returns SQLITE_BUSY. 9473** 9474** ^If any other error occurs while flushing dirty pages to disk (for 9475** example an IO error or out-of-memory condition), then processing is 9476** abandoned and an SQLite [error code] is returned to the caller immediately. 9477** 9478** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 9479** 9480** ^This function does not set the database handle error code or message 9481** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 9482*/ 9483int sqlite3_db_cacheflush(sqlite3*); 9484 9485/* 9486** CAPI3REF: The pre-update hook. 9487** METHOD: sqlite3 9488** 9489** ^These interfaces are only available if SQLite is compiled using the 9490** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 9491** 9492** ^The [sqlite3_preupdate_hook()] interface registers a callback function 9493** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 9494** on a database table. 9495** ^At most one preupdate hook may be registered at a time on a single 9496** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 9497** the previous setting. 9498** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 9499** with a NULL pointer as the second parameter. 9500** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 9501** the first parameter to callbacks. 9502** 9503** ^The preupdate hook only fires for changes to real database tables; the 9504** preupdate hook is not invoked for changes to [virtual tables] or to 9505** system tables like sqlite_sequence or sqlite_stat1. 9506** 9507** ^The second parameter to the preupdate callback is a pointer to 9508** the [database connection] that registered the preupdate hook. 9509** ^The third parameter to the preupdate callback is one of the constants 9510** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 9511** kind of update operation that is about to occur. 9512** ^(The fourth parameter to the preupdate callback is the name of the 9513** database within the database connection that is being modified. This 9514** will be "main" for the main database or "temp" for TEMP tables or 9515** the name given after the AS keyword in the [ATTACH] statement for attached 9516** databases.)^ 9517** ^The fifth parameter to the preupdate callback is the name of the 9518** table that is being modified. 9519** 9520** For an UPDATE or DELETE operation on a [rowid table], the sixth 9521** parameter passed to the preupdate callback is the initial [rowid] of the 9522** row being modified or deleted. For an INSERT operation on a rowid table, 9523** or any operation on a WITHOUT ROWID table, the value of the sixth 9524** parameter is undefined. For an INSERT or UPDATE on a rowid table the 9525** seventh parameter is the final rowid value of the row being inserted 9526** or updated. The value of the seventh parameter passed to the callback 9527** function is not defined for operations on WITHOUT ROWID tables, or for 9528** DELETE operations on rowid tables. 9529** 9530** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 9531** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 9532** provide additional information about a preupdate event. These routines 9533** may only be called from within a preupdate callback. Invoking any of 9534** these routines from outside of a preupdate callback or with a 9535** [database connection] pointer that is different from the one supplied 9536** to the preupdate callback results in undefined and probably undesirable 9537** behavior. 9538** 9539** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 9540** in the row that is being inserted, updated, or deleted. 9541** 9542** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 9543** a [protected sqlite3_value] that contains the value of the Nth column of 9544** the table row before it is updated. The N parameter must be between 0 9545** and one less than the number of columns or the behavior will be 9546** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 9547** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 9548** behavior is undefined. The [sqlite3_value] that P points to 9549** will be destroyed when the preupdate callback returns. 9550** 9551** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 9552** a [protected sqlite3_value] that contains the value of the Nth column of 9553** the table row after it is updated. The N parameter must be between 0 9554** and one less than the number of columns or the behavior will be 9555** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 9556** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 9557** behavior is undefined. The [sqlite3_value] that P points to 9558** will be destroyed when the preupdate callback returns. 9559** 9560** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 9561** callback was invoked as a result of a direct insert, update, or delete 9562** operation; or 1 for inserts, updates, or deletes invoked by top-level 9563** triggers; or 2 for changes resulting from triggers called by top-level 9564** triggers; and so forth. 9565** 9566** When the [sqlite3_blob_write()] API is used to update a blob column, 9567** the pre-update hook is invoked with SQLITE_DELETE. This is because the 9568** in this case the new values are not available. In this case, when a 9569** callback made with op==SQLITE_DELETE is actuall a write using the 9570** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns 9571** the index of the column being written. In other cases, where the 9572** pre-update hook is being invoked for some other reason, including a 9573** regular DELETE, sqlite3_preupdate_blobwrite() returns -1. 9574** 9575** See also: [sqlite3_update_hook()] 9576*/ 9577#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 9578void *sqlite3_preupdate_hook( 9579 sqlite3 *db, 9580 void(*xPreUpdate)( 9581 void *pCtx, /* Copy of third arg to preupdate_hook() */ 9582 sqlite3 *db, /* Database handle */ 9583 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 9584 char const *zDb, /* Database name */ 9585 char const *zName, /* Table name */ 9586 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 9587 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 9588 ), 9589 void* 9590); 9591int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 9592int sqlite3_preupdate_count(sqlite3 *); 9593int sqlite3_preupdate_depth(sqlite3 *); 9594int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 9595int sqlite3_preupdate_blobwrite(sqlite3 *); 9596#endif 9597 9598/* 9599** CAPI3REF: Low-level system error code 9600** METHOD: sqlite3 9601** 9602** ^Attempt to return the underlying operating system error code or error 9603** number that caused the most recent I/O error or failure to open a file. 9604** The return value is OS-dependent. For example, on unix systems, after 9605** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 9606** called to get back the underlying "errno" that caused the problem, such 9607** as ENOSPC, EAUTH, EISDIR, and so forth. 9608*/ 9609int sqlite3_system_errno(sqlite3*); 9610 9611/* 9612** CAPI3REF: Database Snapshot 9613** KEYWORDS: {snapshot} {sqlite3_snapshot} 9614** 9615** An instance of the snapshot object records the state of a [WAL mode] 9616** database for some specific point in history. 9617** 9618** In [WAL mode], multiple [database connections] that are open on the 9619** same database file can each be reading a different historical version 9620** of the database file. When a [database connection] begins a read 9621** transaction, that connection sees an unchanging copy of the database 9622** as it existed for the point in time when the transaction first started. 9623** Subsequent changes to the database from other connections are not seen 9624** by the reader until a new read transaction is started. 9625** 9626** The sqlite3_snapshot object records state information about an historical 9627** version of the database file so that it is possible to later open a new read 9628** transaction that sees that historical version of the database rather than 9629** the most recent version. 9630*/ 9631typedef struct sqlite3_snapshot { 9632 unsigned char hidden[48]; 9633} sqlite3_snapshot; 9634 9635/* 9636** CAPI3REF: Record A Database Snapshot 9637** CONSTRUCTOR: sqlite3_snapshot 9638** 9639** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 9640** new [sqlite3_snapshot] object that records the current state of 9641** schema S in database connection D. ^On success, the 9642** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 9643** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 9644** If there is not already a read-transaction open on schema S when 9645** this function is called, one is opened automatically. 9646** 9647** The following must be true for this function to succeed. If any of 9648** the following statements are false when sqlite3_snapshot_get() is 9649** called, SQLITE_ERROR is returned. The final value of *P is undefined 9650** in this case. 9651** 9652** <ul> 9653** <li> The database handle must not be in [autocommit mode]. 9654** 9655** <li> Schema S of [database connection] D must be a [WAL mode] database. 9656** 9657** <li> There must not be a write transaction open on schema S of database 9658** connection D. 9659** 9660** <li> One or more transactions must have been written to the current wal 9661** file since it was created on disk (by any connection). This means 9662** that a snapshot cannot be taken on a wal mode database with no wal 9663** file immediately after it is first opened. At least one transaction 9664** must be written to it first. 9665** </ul> 9666** 9667** This function may also return SQLITE_NOMEM. If it is called with the 9668** database handle in autocommit mode but fails for some other reason, 9669** whether or not a read transaction is opened on schema S is undefined. 9670** 9671** The [sqlite3_snapshot] object returned from a successful call to 9672** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 9673** to avoid a memory leak. 9674** 9675** The [sqlite3_snapshot_get()] interface is only available when the 9676** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9677*/ 9678SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 9679 sqlite3 *db, 9680 const char *zSchema, 9681 sqlite3_snapshot **ppSnapshot 9682); 9683 9684/* 9685** CAPI3REF: Start a read transaction on an historical snapshot 9686** METHOD: sqlite3_snapshot 9687** 9688** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read 9689** transaction or upgrades an existing one for schema S of 9690** [database connection] D such that the read transaction refers to 9691** historical [snapshot] P, rather than the most recent change to the 9692** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK 9693** on success or an appropriate [error code] if it fails. 9694** 9695** ^In order to succeed, the database connection must not be in 9696** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there 9697** is already a read transaction open on schema S, then the database handle 9698** must have no active statements (SELECT statements that have been passed 9699** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()). 9700** SQLITE_ERROR is returned if either of these conditions is violated, or 9701** if schema S does not exist, or if the snapshot object is invalid. 9702** 9703** ^A call to sqlite3_snapshot_open() will fail to open if the specified 9704** snapshot has been overwritten by a [checkpoint]. In this case 9705** SQLITE_ERROR_SNAPSHOT is returned. 9706** 9707** If there is already a read transaction open when this function is 9708** invoked, then the same read transaction remains open (on the same 9709** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT 9710** is returned. If another error code - for example SQLITE_PROTOCOL or an 9711** SQLITE_IOERR error code - is returned, then the final state of the 9712** read transaction is undefined. If SQLITE_OK is returned, then the 9713** read transaction is now open on database snapshot P. 9714** 9715** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 9716** database connection D does not know that the database file for 9717** schema S is in [WAL mode]. A database connection might not know 9718** that the database file is in [WAL mode] if there has been no prior 9719** I/O on that database connection, or if the database entered [WAL mode] 9720** after the most recent I/O on the database connection.)^ 9721** (Hint: Run "[PRAGMA application_id]" against a newly opened 9722** database connection in order to make it ready to use snapshots.) 9723** 9724** The [sqlite3_snapshot_open()] interface is only available when the 9725** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9726*/ 9727SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 9728 sqlite3 *db, 9729 const char *zSchema, 9730 sqlite3_snapshot *pSnapshot 9731); 9732 9733/* 9734** CAPI3REF: Destroy a snapshot 9735** DESTRUCTOR: sqlite3_snapshot 9736** 9737** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 9738** The application must eventually free every [sqlite3_snapshot] object 9739** using this routine to avoid a memory leak. 9740** 9741** The [sqlite3_snapshot_free()] interface is only available when the 9742** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9743*/ 9744SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 9745 9746/* 9747** CAPI3REF: Compare the ages of two snapshot handles. 9748** METHOD: sqlite3_snapshot 9749** 9750** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 9751** of two valid snapshot handles. 9752** 9753** If the two snapshot handles are not associated with the same database 9754** file, the result of the comparison is undefined. 9755** 9756** Additionally, the result of the comparison is only valid if both of the 9757** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 9758** last time the wal file was deleted. The wal file is deleted when the 9759** database is changed back to rollback mode or when the number of database 9760** clients drops to zero. If either snapshot handle was obtained before the 9761** wal file was last deleted, the value returned by this function 9762** is undefined. 9763** 9764** Otherwise, this API returns a negative value if P1 refers to an older 9765** snapshot than P2, zero if the two handles refer to the same database 9766** snapshot, and a positive value if P1 is a newer snapshot than P2. 9767** 9768** This interface is only available if SQLite is compiled with the 9769** [SQLITE_ENABLE_SNAPSHOT] option. 9770*/ 9771SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 9772 sqlite3_snapshot *p1, 9773 sqlite3_snapshot *p2 9774); 9775 9776/* 9777** CAPI3REF: Recover snapshots from a wal file 9778** METHOD: sqlite3_snapshot 9779** 9780** If a [WAL file] remains on disk after all database connections close 9781** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control] 9782** or because the last process to have the database opened exited without 9783** calling [sqlite3_close()]) and a new connection is subsequently opened 9784** on that database and [WAL file], the [sqlite3_snapshot_open()] interface 9785** will only be able to open the last transaction added to the WAL file 9786** even though the WAL file contains other valid transactions. 9787** 9788** This function attempts to scan the WAL file associated with database zDb 9789** of database handle db and make all valid snapshots available to 9790** sqlite3_snapshot_open(). It is an error if there is already a read 9791** transaction open on the database, or if the database is not a WAL mode 9792** database. 9793** 9794** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 9795** 9796** This interface is only available if SQLite is compiled with the 9797** [SQLITE_ENABLE_SNAPSHOT] option. 9798*/ 9799SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 9800 9801/* 9802** CAPI3REF: Serialize a database 9803** 9804** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 9805** that is a serialization of the S database on [database connection] D. 9806** If P is not a NULL pointer, then the size of the database in bytes 9807** is written into *P. 9808** 9809** For an ordinary on-disk database file, the serialization is just a 9810** copy of the disk file. For an in-memory database or a "TEMP" database, 9811** the serialization is the same sequence of bytes which would be written 9812** to disk if that database where backed up to disk. 9813** 9814** The usual case is that sqlite3_serialize() copies the serialization of 9815** the database into memory obtained from [sqlite3_malloc64()] and returns 9816** a pointer to that memory. The caller is responsible for freeing the 9817** returned value to avoid a memory leak. However, if the F argument 9818** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 9819** are made, and the sqlite3_serialize() function will return a pointer 9820** to the contiguous memory representation of the database that SQLite 9821** is currently using for that database, or NULL if the no such contiguous 9822** memory representation of the database exists. A contiguous memory 9823** representation of the database will usually only exist if there has 9824** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 9825** values of D and S. 9826** The size of the database is written into *P even if the 9827** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy 9828** of the database exists. 9829** 9830** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 9831** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 9832** allocation error occurs. 9833** 9834** This interface is omitted if SQLite is compiled with the 9835** [SQLITE_OMIT_DESERIALIZE] option. 9836*/ 9837unsigned char *sqlite3_serialize( 9838 sqlite3 *db, /* The database connection */ 9839 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 9840 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 9841 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 9842); 9843 9844/* 9845** CAPI3REF: Flags for sqlite3_serialize 9846** 9847** Zero or more of the following constants can be OR-ed together for 9848** the F argument to [sqlite3_serialize(D,S,P,F)]. 9849** 9850** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 9851** a pointer to contiguous in-memory database that it is currently using, 9852** without making a copy of the database. If SQLite is not currently using 9853** a contiguous in-memory database, then this option causes 9854** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 9855** using a contiguous in-memory database if it has been initialized by a 9856** prior call to [sqlite3_deserialize()]. 9857*/ 9858#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 9859 9860/* 9861** CAPI3REF: Deserialize a database 9862** 9863** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 9864** [database connection] D to disconnect from database S and then 9865** reopen S as an in-memory database based on the serialization contained 9866** in P. The serialized database P is N bytes in size. M is the size of 9867** the buffer P, which might be larger than N. If M is larger than N, and 9868** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 9869** permitted to add content to the in-memory database as long as the total 9870** size does not exceed M bytes. 9871** 9872** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 9873** invoke sqlite3_free() on the serialization buffer when the database 9874** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 9875** SQLite will try to increase the buffer size using sqlite3_realloc64() 9876** if writes on the database cause it to grow larger than M bytes. 9877** 9878** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 9879** database is currently in a read transaction or is involved in a backup 9880** operation. 9881** 9882** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 9883** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 9884** [sqlite3_free()] is invoked on argument P prior to returning. 9885** 9886** This interface is omitted if SQLite is compiled with the 9887** [SQLITE_OMIT_DESERIALIZE] option. 9888*/ 9889int sqlite3_deserialize( 9890 sqlite3 *db, /* The database connection */ 9891 const char *zSchema, /* Which DB to reopen with the deserialization */ 9892 unsigned char *pData, /* The serialized database content */ 9893 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 9894 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 9895 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 9896); 9897 9898/* 9899** CAPI3REF: Flags for sqlite3_deserialize() 9900** 9901** The following are allowed values for 6th argument (the F argument) to 9902** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 9903** 9904** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 9905** in the P argument is held in memory obtained from [sqlite3_malloc64()] 9906** and that SQLite should take ownership of this memory and automatically 9907** free it when it has finished using it. Without this flag, the caller 9908** is responsible for freeing any dynamically allocated memory. 9909** 9910** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 9911** grow the size of the database using calls to [sqlite3_realloc64()]. This 9912** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 9913** Without this flag, the deserialized database cannot increase in size beyond 9914** the number of bytes specified by the M parameter. 9915** 9916** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 9917** should be treated as read-only. 9918*/ 9919#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 9920#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 9921#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 9922 9923/* 9924** Undo the hack that converts floating point types to integer for 9925** builds on processors without floating point support. 9926*/ 9927#ifdef SQLITE_OMIT_FLOATING_POINT 9928# undef double 9929#endif 9930 9931#ifdef __cplusplus 9932} /* End of the 'extern "C"' block */ 9933#endif 9934#endif /* SQLITE3_H */ 9935