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*/ 4202int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 4203 4204/* 4205** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement 4206** METHOD: sqlite3_stmt 4207** 4208** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the 4209** prepared statement S is an EXPLAIN statement, or 2 if the 4210** statement S is an EXPLAIN QUERY PLAN. 4211** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is 4212** an ordinary statement or a NULL pointer. 4213*/ 4214int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt); 4215 4216/* 4217** CAPI3REF: Determine If A Prepared Statement Has Been Reset 4218** METHOD: sqlite3_stmt 4219** 4220** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 4221** [prepared statement] S has been stepped at least once using 4222** [sqlite3_step(S)] but has neither run to completion (returned 4223** [SQLITE_DONE] from [sqlite3_step(S)]) nor 4224** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 4225** interface returns false if S is a NULL pointer. If S is not a 4226** NULL pointer and is not a pointer to a valid [prepared statement] 4227** object, then the behavior is undefined and probably undesirable. 4228** 4229** This interface can be used in combination [sqlite3_next_stmt()] 4230** to locate all prepared statements associated with a database 4231** connection that are in need of being reset. This can be used, 4232** for example, in diagnostic routines to search for prepared 4233** statements that are holding a transaction open. 4234*/ 4235int sqlite3_stmt_busy(sqlite3_stmt*); 4236 4237/* 4238** CAPI3REF: Dynamically Typed Value Object 4239** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 4240** 4241** SQLite uses the sqlite3_value object to represent all values 4242** that can be stored in a database table. SQLite uses dynamic typing 4243** for the values it stores. ^Values stored in sqlite3_value objects 4244** can be integers, floating point values, strings, BLOBs, or NULL. 4245** 4246** An sqlite3_value object may be either "protected" or "unprotected". 4247** Some interfaces require a protected sqlite3_value. Other interfaces 4248** will accept either a protected or an unprotected sqlite3_value. 4249** Every interface that accepts sqlite3_value arguments specifies 4250** whether or not it requires a protected sqlite3_value. The 4251** [sqlite3_value_dup()] interface can be used to construct a new 4252** protected sqlite3_value from an unprotected sqlite3_value. 4253** 4254** The terms "protected" and "unprotected" refer to whether or not 4255** a mutex is held. An internal mutex is held for a protected 4256** sqlite3_value object but no mutex is held for an unprotected 4257** sqlite3_value object. If SQLite is compiled to be single-threaded 4258** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 4259** or if SQLite is run in one of reduced mutex modes 4260** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 4261** then there is no distinction between protected and unprotected 4262** sqlite3_value objects and they can be used interchangeably. However, 4263** for maximum code portability it is recommended that applications 4264** still make the distinction between protected and unprotected 4265** sqlite3_value objects even when not strictly required. 4266** 4267** ^The sqlite3_value objects that are passed as parameters into the 4268** implementation of [application-defined SQL functions] are protected. 4269** ^The sqlite3_value object returned by 4270** [sqlite3_column_value()] is unprotected. 4271** Unprotected sqlite3_value objects may only be used as arguments 4272** to [sqlite3_result_value()], [sqlite3_bind_value()], and 4273** [sqlite3_value_dup()]. 4274** The [sqlite3_value_blob | sqlite3_value_type()] family of 4275** interfaces require protected sqlite3_value objects. 4276*/ 4277typedef struct sqlite3_value sqlite3_value; 4278 4279/* 4280** CAPI3REF: SQL Function Context Object 4281** 4282** The context in which an SQL function executes is stored in an 4283** sqlite3_context object. ^A pointer to an sqlite3_context object 4284** is always first parameter to [application-defined SQL functions]. 4285** The application-defined SQL function implementation will pass this 4286** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 4287** [sqlite3_aggregate_context()], [sqlite3_user_data()], 4288** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 4289** and/or [sqlite3_set_auxdata()]. 4290*/ 4291typedef struct sqlite3_context sqlite3_context; 4292 4293/* 4294** CAPI3REF: Binding Values To Prepared Statements 4295** KEYWORDS: {host parameter} {host parameters} {host parameter name} 4296** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 4297** METHOD: sqlite3_stmt 4298** 4299** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 4300** literals may be replaced by a [parameter] that matches one of following 4301** templates: 4302** 4303** <ul> 4304** <li> ? 4305** <li> ?NNN 4306** <li> :VVV 4307** <li> @VVV 4308** <li> $VVV 4309** </ul> 4310** 4311** In the templates above, NNN represents an integer literal, 4312** and VVV represents an alphanumeric identifier.)^ ^The values of these 4313** parameters (also called "host parameter names" or "SQL parameters") 4314** can be set using the sqlite3_bind_*() routines defined here. 4315** 4316** ^The first argument to the sqlite3_bind_*() routines is always 4317** a pointer to the [sqlite3_stmt] object returned from 4318** [sqlite3_prepare_v2()] or its variants. 4319** 4320** ^The second argument is the index of the SQL parameter to be set. 4321** ^The leftmost SQL parameter has an index of 1. ^When the same named 4322** SQL parameter is used more than once, second and subsequent 4323** occurrences have the same index as the first occurrence. 4324** ^The index for named parameters can be looked up using the 4325** [sqlite3_bind_parameter_index()] API if desired. ^The index 4326** for "?NNN" parameters is the value of NNN. 4327** ^The NNN value must be between 1 and the [sqlite3_limit()] 4328** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766). 4329** 4330** ^The third argument is the value to bind to the parameter. 4331** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4332** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 4333** is ignored and the end result is the same as sqlite3_bind_null(). 4334** ^If the third parameter to sqlite3_bind_text() is not NULL, then 4335** it should be a pointer to well-formed UTF8 text. 4336** ^If the third parameter to sqlite3_bind_text16() is not NULL, then 4337** it should be a pointer to well-formed UTF16 text. 4338** ^If the third parameter to sqlite3_bind_text64() is not NULL, then 4339** it should be a pointer to a well-formed unicode string that is 4340** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16 4341** otherwise. 4342** 4343** [[byte-order determination rules]] ^The byte-order of 4344** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF) 4345** found in first character, which is removed, or in the absence of a BOM 4346** the byte order is the native byte order of the host 4347** machine for sqlite3_bind_text16() or the byte order specified in 4348** the 6th parameter for sqlite3_bind_text64().)^ 4349** ^If UTF16 input text contains invalid unicode 4350** characters, then SQLite might change those invalid characters 4351** into the unicode replacement character: U+FFFD. 4352** 4353** ^(In those routines that have a fourth argument, its value is the 4354** number of bytes in the parameter. To be clear: the value is the 4355** number of <u>bytes</u> in the value, not the number of characters.)^ 4356** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4357** is negative, then the length of the string is 4358** the number of bytes up to the first zero terminator. 4359** If the fourth parameter to sqlite3_bind_blob() is negative, then 4360** the behavior is undefined. 4361** If a non-negative fourth parameter is provided to sqlite3_bind_text() 4362** or sqlite3_bind_text16() or sqlite3_bind_text64() then 4363** that parameter must be the byte offset 4364** where the NUL terminator would occur assuming the string were NUL 4365** terminated. If any NUL characters occurs at byte offsets less than 4366** the value of the fourth parameter then the resulting string value will 4367** contain embedded NULs. The result of expressions involving strings 4368** with embedded NULs is undefined. 4369** 4370** ^The fifth argument to the BLOB and string binding interfaces controls 4371** or indicates the lifetime of the object referenced by the third parameter. 4372** ^These three options exist: 4373** ^(1) A destructor to dispose of the BLOB or string after SQLite has finished 4374** with it may be passed. ^It is called to dispose of the BLOB or string even 4375** if the call to the bind API fails, except the destructor is not called if 4376** the third parameter is a NULL pointer or the fourth parameter is negative. 4377** ^(2) The special constant, [SQLITE_STATIC], may be passsed to indicate that 4378** the application remains responsible for disposing of the object. ^In this 4379** case, the object and the provided pointer to it must remain valid until 4380** either the prepared statement is finalized or the same SQL parameter is 4381** bound to something else, whichever occurs sooner. 4382** ^(3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the 4383** object is to be copied prior to the return from sqlite3_bind_*(). ^The 4384** object and pointer to it must remain valid until then. ^SQLite will then 4385** manage the lifetime of its private copy. 4386** 4387** ^The sixth argument to sqlite3_bind_text64() must be one of 4388** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 4389** to specify the encoding of the text in the third parameter. If 4390** the sixth argument to sqlite3_bind_text64() is not one of the 4391** allowed values shown above, or if the text encoding is different 4392** from the encoding specified by the sixth parameter, then the behavior 4393** is undefined. 4394** 4395** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 4396** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 4397** (just an integer to hold its size) while it is being processed. 4398** Zeroblobs are intended to serve as placeholders for BLOBs whose 4399** content is later written using 4400** [sqlite3_blob_open | incremental BLOB I/O] routines. 4401** ^A negative value for the zeroblob results in a zero-length BLOB. 4402** 4403** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 4404** [prepared statement] S to have an SQL value of NULL, but to also be 4405** associated with the pointer P of type T. ^D is either a NULL pointer or 4406** a pointer to a destructor function for P. ^SQLite will invoke the 4407** destructor D with a single argument of P when it is finished using 4408** P. The T parameter should be a static string, preferably a string 4409** literal. The sqlite3_bind_pointer() routine is part of the 4410** [pointer passing interface] added for SQLite 3.20.0. 4411** 4412** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 4413** for the [prepared statement] or with a prepared statement for which 4414** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 4415** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 4416** routine is passed a [prepared statement] that has been finalized, the 4417** result is undefined and probably harmful. 4418** 4419** ^Bindings are not cleared by the [sqlite3_reset()] routine. 4420** ^Unbound parameters are interpreted as NULL. 4421** 4422** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 4423** [error code] if anything goes wrong. 4424** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 4425** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 4426** [SQLITE_MAX_LENGTH]. 4427** ^[SQLITE_RANGE] is returned if the parameter 4428** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 4429** 4430** See also: [sqlite3_bind_parameter_count()], 4431** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 4432*/ 4433int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 4434int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 4435 void(*)(void*)); 4436int sqlite3_bind_double(sqlite3_stmt*, int, double); 4437int sqlite3_bind_int(sqlite3_stmt*, int, int); 4438int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 4439int sqlite3_bind_null(sqlite3_stmt*, int); 4440int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 4441int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 4442int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 4443 void(*)(void*), unsigned char encoding); 4444int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 4445int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 4446int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 4447int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 4448 4449/* 4450** CAPI3REF: Number Of SQL Parameters 4451** METHOD: sqlite3_stmt 4452** 4453** ^This routine can be used to find the number of [SQL parameters] 4454** in a [prepared statement]. SQL parameters are tokens of the 4455** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4456** placeholders for values that are [sqlite3_bind_blob | bound] 4457** to the parameters at a later time. 4458** 4459** ^(This routine actually returns the index of the largest (rightmost) 4460** parameter. For all forms except ?NNN, this will correspond to the 4461** number of unique parameters. If parameters of the ?NNN form are used, 4462** there may be gaps in the list.)^ 4463** 4464** See also: [sqlite3_bind_blob|sqlite3_bind()], 4465** [sqlite3_bind_parameter_name()], and 4466** [sqlite3_bind_parameter_index()]. 4467*/ 4468int sqlite3_bind_parameter_count(sqlite3_stmt*); 4469 4470/* 4471** CAPI3REF: Name Of A Host Parameter 4472** METHOD: sqlite3_stmt 4473** 4474** ^The sqlite3_bind_parameter_name(P,N) interface returns 4475** the name of the N-th [SQL parameter] in the [prepared statement] P. 4476** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4477** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4478** respectively. 4479** In other words, the initial ":" or "$" or "@" or "?" 4480** is included as part of the name.)^ 4481** ^Parameters of the form "?" without a following integer have no name 4482** and are referred to as "nameless" or "anonymous parameters". 4483** 4484** ^The first host parameter has an index of 1, not 0. 4485** 4486** ^If the value N is out of range or if the N-th parameter is 4487** nameless, then NULL is returned. ^The returned string is 4488** always in UTF-8 encoding even if the named parameter was 4489** originally specified as UTF-16 in [sqlite3_prepare16()], 4490** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4491** 4492** See also: [sqlite3_bind_blob|sqlite3_bind()], 4493** [sqlite3_bind_parameter_count()], and 4494** [sqlite3_bind_parameter_index()]. 4495*/ 4496const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4497 4498/* 4499** CAPI3REF: Index Of A Parameter With A Given Name 4500** METHOD: sqlite3_stmt 4501** 4502** ^Return the index of an SQL parameter given its name. ^The 4503** index value returned is suitable for use as the second 4504** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4505** is returned if no matching parameter is found. ^The parameter 4506** name must be given in UTF-8 even if the original statement 4507** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4508** [sqlite3_prepare16_v3()]. 4509** 4510** See also: [sqlite3_bind_blob|sqlite3_bind()], 4511** [sqlite3_bind_parameter_count()], and 4512** [sqlite3_bind_parameter_name()]. 4513*/ 4514int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4515 4516/* 4517** CAPI3REF: Reset All Bindings On A Prepared Statement 4518** METHOD: sqlite3_stmt 4519** 4520** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4521** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4522** ^Use this routine to reset all host parameters to NULL. 4523*/ 4524int sqlite3_clear_bindings(sqlite3_stmt*); 4525 4526/* 4527** CAPI3REF: Number Of Columns In A Result Set 4528** METHOD: sqlite3_stmt 4529** 4530** ^Return the number of columns in the result set returned by the 4531** [prepared statement]. ^If this routine returns 0, that means the 4532** [prepared statement] returns no data (for example an [UPDATE]). 4533** ^However, just because this routine returns a positive number does not 4534** mean that one or more rows of data will be returned. ^A SELECT statement 4535** will always have a positive sqlite3_column_count() but depending on the 4536** WHERE clause constraints and the table content, it might return no rows. 4537** 4538** See also: [sqlite3_data_count()] 4539*/ 4540int sqlite3_column_count(sqlite3_stmt *pStmt); 4541 4542/* 4543** CAPI3REF: Column Names In A Result Set 4544** METHOD: sqlite3_stmt 4545** 4546** ^These routines return the name assigned to a particular column 4547** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4548** interface returns a pointer to a zero-terminated UTF-8 string 4549** and sqlite3_column_name16() returns a pointer to a zero-terminated 4550** UTF-16 string. ^The first parameter is the [prepared statement] 4551** that implements the [SELECT] statement. ^The second parameter is the 4552** column number. ^The leftmost column is number 0. 4553** 4554** ^The returned string pointer is valid until either the [prepared statement] 4555** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4556** reprepared by the first call to [sqlite3_step()] for a particular run 4557** or until the next call to 4558** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4559** 4560** ^If sqlite3_malloc() fails during the processing of either routine 4561** (for example during a conversion from UTF-8 to UTF-16) then a 4562** NULL pointer is returned. 4563** 4564** ^The name of a result column is the value of the "AS" clause for 4565** that column, if there is an AS clause. If there is no AS clause 4566** then the name of the column is unspecified and may change from 4567** one release of SQLite to the next. 4568*/ 4569const char *sqlite3_column_name(sqlite3_stmt*, int N); 4570const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4571 4572/* 4573** CAPI3REF: Source Of Data In A Query Result 4574** METHOD: sqlite3_stmt 4575** 4576** ^These routines provide a means to determine the database, table, and 4577** table column that is the origin of a particular result column in 4578** [SELECT] statement. 4579** ^The name of the database or table or column can be returned as 4580** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4581** the database name, the _table_ routines return the table name, and 4582** the origin_ routines return the column name. 4583** ^The returned string is valid until the [prepared statement] is destroyed 4584** using [sqlite3_finalize()] or until the statement is automatically 4585** reprepared by the first call to [sqlite3_step()] for a particular run 4586** or until the same information is requested 4587** again in a different encoding. 4588** 4589** ^The names returned are the original un-aliased names of the 4590** database, table, and column. 4591** 4592** ^The first argument to these interfaces is a [prepared statement]. 4593** ^These functions return information about the Nth result column returned by 4594** the statement, where N is the second function argument. 4595** ^The left-most column is column 0 for these routines. 4596** 4597** ^If the Nth column returned by the statement is an expression or 4598** subquery and is not a column value, then all of these functions return 4599** NULL. ^These routines might also return NULL if a memory allocation error 4600** occurs. ^Otherwise, they return the name of the attached database, table, 4601** or column that query result column was extracted from. 4602** 4603** ^As with all other SQLite APIs, those whose names end with "16" return 4604** UTF-16 encoded strings and the other functions return UTF-8. 4605** 4606** ^These APIs are only available if the library was compiled with the 4607** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4608** 4609** If two or more threads call one or more 4610** [sqlite3_column_database_name | column metadata interfaces] 4611** for the same [prepared statement] and result column 4612** at the same time then the results are undefined. 4613*/ 4614const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4615const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4616const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4617const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4618const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4619const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4620 4621/* 4622** CAPI3REF: Declared Datatype Of A Query Result 4623** METHOD: sqlite3_stmt 4624** 4625** ^(The first parameter is a [prepared statement]. 4626** If this statement is a [SELECT] statement and the Nth column of the 4627** returned result set of that [SELECT] is a table column (not an 4628** expression or subquery) then the declared type of the table 4629** column is returned.)^ ^If the Nth column of the result set is an 4630** expression or subquery, then a NULL pointer is returned. 4631** ^The returned string is always UTF-8 encoded. 4632** 4633** ^(For example, given the database schema: 4634** 4635** CREATE TABLE t1(c1 VARIANT); 4636** 4637** and the following statement to be compiled: 4638** 4639** SELECT c1 + 1, c1 FROM t1; 4640** 4641** this routine would return the string "VARIANT" for the second result 4642** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4643** 4644** ^SQLite uses dynamic run-time typing. ^So just because a column 4645** is declared to contain a particular type does not mean that the 4646** data stored in that column is of the declared type. SQLite is 4647** strongly typed, but the typing is dynamic not static. ^Type 4648** is associated with individual values, not with the containers 4649** used to hold those values. 4650*/ 4651const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4652const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4653 4654/* 4655** CAPI3REF: Evaluate An SQL Statement 4656** METHOD: sqlite3_stmt 4657** 4658** After a [prepared statement] has been prepared using any of 4659** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4660** or [sqlite3_prepare16_v3()] or one of the legacy 4661** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4662** must be called one or more times to evaluate the statement. 4663** 4664** The details of the behavior of the sqlite3_step() interface depend 4665** on whether the statement was prepared using the newer "vX" interfaces 4666** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4667** [sqlite3_prepare16_v2()] or the older legacy 4668** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4669** new "vX" interface is recommended for new applications but the legacy 4670** interface will continue to be supported. 4671** 4672** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4673** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4674** ^With the "v2" interface, any of the other [result codes] or 4675** [extended result codes] might be returned as well. 4676** 4677** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4678** database locks it needs to do its job. ^If the statement is a [COMMIT] 4679** or occurs outside of an explicit transaction, then you can retry the 4680** statement. If the statement is not a [COMMIT] and occurs within an 4681** explicit transaction then you should rollback the transaction before 4682** continuing. 4683** 4684** ^[SQLITE_DONE] means that the statement has finished executing 4685** successfully. sqlite3_step() should not be called again on this virtual 4686** machine without first calling [sqlite3_reset()] to reset the virtual 4687** machine back to its initial state. 4688** 4689** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4690** is returned each time a new row of data is ready for processing by the 4691** caller. The values may be accessed using the [column access functions]. 4692** sqlite3_step() is called again to retrieve the next row of data. 4693** 4694** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4695** violation) has occurred. sqlite3_step() should not be called again on 4696** the VM. More information may be found by calling [sqlite3_errmsg()]. 4697** ^With the legacy interface, a more specific error code (for example, 4698** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4699** can be obtained by calling [sqlite3_reset()] on the 4700** [prepared statement]. ^In the "v2" interface, 4701** the more specific error code is returned directly by sqlite3_step(). 4702** 4703** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4704** Perhaps it was called on a [prepared statement] that has 4705** already been [sqlite3_finalize | finalized] or on one that had 4706** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4707** be the case that the same database connection is being used by two or 4708** more threads at the same moment in time. 4709** 4710** For all versions of SQLite up to and including 3.6.23.1, a call to 4711** [sqlite3_reset()] was required after sqlite3_step() returned anything 4712** other than [SQLITE_ROW] before any subsequent invocation of 4713** sqlite3_step(). Failure to reset the prepared statement using 4714** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4715** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4716** sqlite3_step() began 4717** calling [sqlite3_reset()] automatically in this circumstance rather 4718** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4719** break because any application that ever receives an SQLITE_MISUSE error 4720** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4721** can be used to restore the legacy behavior. 4722** 4723** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4724** API always returns a generic error code, [SQLITE_ERROR], following any 4725** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4726** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4727** specific [error codes] that better describes the error. 4728** We admit that this is a goofy design. The problem has been fixed 4729** with the "v2" interface. If you prepare all of your SQL statements 4730** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4731** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4732** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4733** then the more specific [error codes] are returned directly 4734** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4735*/ 4736int sqlite3_step(sqlite3_stmt*); 4737 4738/* 4739** CAPI3REF: Number of columns in a result set 4740** METHOD: sqlite3_stmt 4741** 4742** ^The sqlite3_data_count(P) interface returns the number of columns in the 4743** current row of the result set of [prepared statement] P. 4744** ^If prepared statement P does not have results ready to return 4745** (via calls to the [sqlite3_column_int | sqlite3_column()] family of 4746** interfaces) then sqlite3_data_count(P) returns 0. 4747** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4748** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4749** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4750** will return non-zero if previous call to [sqlite3_step](P) returned 4751** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4752** where it always returns zero since each step of that multi-step 4753** pragma returns 0 columns of data. 4754** 4755** See also: [sqlite3_column_count()] 4756*/ 4757int sqlite3_data_count(sqlite3_stmt *pStmt); 4758 4759/* 4760** CAPI3REF: Fundamental Datatypes 4761** KEYWORDS: SQLITE_TEXT 4762** 4763** ^(Every value in SQLite has one of five fundamental datatypes: 4764** 4765** <ul> 4766** <li> 64-bit signed integer 4767** <li> 64-bit IEEE floating point number 4768** <li> string 4769** <li> BLOB 4770** <li> NULL 4771** </ul>)^ 4772** 4773** These constants are codes for each of those types. 4774** 4775** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4776** for a completely different meaning. Software that links against both 4777** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4778** SQLITE_TEXT. 4779*/ 4780#define SQLITE_INTEGER 1 4781#define SQLITE_FLOAT 2 4782#define SQLITE_BLOB 4 4783#define SQLITE_NULL 5 4784#ifdef SQLITE_TEXT 4785# undef SQLITE_TEXT 4786#else 4787# define SQLITE_TEXT 3 4788#endif 4789#define SQLITE3_TEXT 3 4790 4791/* 4792** CAPI3REF: Result Values From A Query 4793** KEYWORDS: {column access functions} 4794** METHOD: sqlite3_stmt 4795** 4796** <b>Summary:</b> 4797** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4798** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4799** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4800** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4801** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4802** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4803** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4804** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4805** [sqlite3_value|unprotected sqlite3_value] object. 4806** <tr><td> <td> <td> 4807** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4808** or a UTF-8 TEXT result in bytes 4809** <tr><td><b>sqlite3_column_bytes16 </b> 4810** <td>→ <td>Size of UTF-16 4811** TEXT in bytes 4812** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4813** datatype of the result 4814** </table></blockquote> 4815** 4816** <b>Details:</b> 4817** 4818** ^These routines return information about a single column of the current 4819** result row of a query. ^In every case the first argument is a pointer 4820** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4821** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4822** and the second argument is the index of the column for which information 4823** should be returned. ^The leftmost column of the result set has the index 0. 4824** ^The number of columns in the result can be determined using 4825** [sqlite3_column_count()]. 4826** 4827** If the SQL statement does not currently point to a valid row, or if the 4828** column index is out of range, the result is undefined. 4829** These routines may only be called when the most recent call to 4830** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4831** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4832** If any of these routines are called after [sqlite3_reset()] or 4833** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4834** something other than [SQLITE_ROW], the results are undefined. 4835** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4836** are called from a different thread while any of these routines 4837** are pending, then the results are undefined. 4838** 4839** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4840** each return the value of a result column in a specific data format. If 4841** the result column is not initially in the requested format (for example, 4842** if the query returns an integer but the sqlite3_column_text() interface 4843** is used to extract the value) then an automatic type conversion is performed. 4844** 4845** ^The sqlite3_column_type() routine returns the 4846** [SQLITE_INTEGER | datatype code] for the initial data type 4847** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4848** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4849** The return value of sqlite3_column_type() can be used to decide which 4850** of the first six interface should be used to extract the column value. 4851** The value returned by sqlite3_column_type() is only meaningful if no 4852** automatic type conversions have occurred for the value in question. 4853** After a type conversion, the result of calling sqlite3_column_type() 4854** is undefined, though harmless. Future 4855** versions of SQLite may change the behavior of sqlite3_column_type() 4856** following a type conversion. 4857** 4858** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4859** or sqlite3_column_bytes16() interfaces can be used to determine the size 4860** of that BLOB or string. 4861** 4862** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4863** routine returns the number of bytes in that BLOB or string. 4864** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4865** the string to UTF-8 and then returns the number of bytes. 4866** ^If the result is a numeric value then sqlite3_column_bytes() uses 4867** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4868** the number of bytes in that string. 4869** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4870** 4871** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4872** routine returns the number of bytes in that BLOB or string. 4873** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4874** the string to UTF-16 and then returns the number of bytes. 4875** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4876** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4877** the number of bytes in that string. 4878** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4879** 4880** ^The values returned by [sqlite3_column_bytes()] and 4881** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4882** of the string. ^For clarity: the values returned by 4883** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4884** bytes in the string, not the number of characters. 4885** 4886** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4887** even empty strings, are always zero-terminated. ^The return 4888** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4889** 4890** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4891** [unprotected sqlite3_value] object. In a multithreaded environment, 4892** an unprotected sqlite3_value object may only be used safely with 4893** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4894** If the [unprotected sqlite3_value] object returned by 4895** [sqlite3_column_value()] is used in any other way, including calls 4896** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4897** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4898** Hence, the sqlite3_column_value() interface 4899** is normally only useful within the implementation of 4900** [application-defined SQL functions] or [virtual tables], not within 4901** top-level application code. 4902** 4903** The these routines may attempt to convert the datatype of the result. 4904** ^For example, if the internal representation is FLOAT and a text result 4905** is requested, [sqlite3_snprintf()] is used internally to perform the 4906** conversion automatically. ^(The following table details the conversions 4907** that are applied: 4908** 4909** <blockquote> 4910** <table border="1"> 4911** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4912** 4913** <tr><td> NULL <td> INTEGER <td> Result is 0 4914** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4915** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4916** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4917** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4918** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4919** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4920** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4921** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4922** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4923** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4924** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4925** <tr><td> TEXT <td> BLOB <td> No change 4926** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4927** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4928** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4929** </table> 4930** </blockquote>)^ 4931** 4932** Note that when type conversions occur, pointers returned by prior 4933** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4934** sqlite3_column_text16() may be invalidated. 4935** Type conversions and pointer invalidations might occur 4936** in the following cases: 4937** 4938** <ul> 4939** <li> The initial content is a BLOB and sqlite3_column_text() or 4940** sqlite3_column_text16() is called. A zero-terminator might 4941** need to be added to the string.</li> 4942** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4943** sqlite3_column_text16() is called. The content must be converted 4944** to UTF-16.</li> 4945** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4946** sqlite3_column_text() is called. The content must be converted 4947** to UTF-8.</li> 4948** </ul> 4949** 4950** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4951** not invalidate a prior pointer, though of course the content of the buffer 4952** that the prior pointer references will have been modified. Other kinds 4953** of conversion are done in place when it is possible, but sometimes they 4954** are not possible and in those cases prior pointers are invalidated. 4955** 4956** The safest policy is to invoke these routines 4957** in one of the following ways: 4958** 4959** <ul> 4960** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4961** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4962** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4963** </ul> 4964** 4965** In other words, you should call sqlite3_column_text(), 4966** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4967** into the desired format, then invoke sqlite3_column_bytes() or 4968** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4969** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4970** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4971** with calls to sqlite3_column_bytes(). 4972** 4973** ^The pointers returned are valid until a type conversion occurs as 4974** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4975** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4976** and BLOBs is freed automatically. Do not pass the pointers returned 4977** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4978** [sqlite3_free()]. 4979** 4980** As long as the input parameters are correct, these routines will only 4981** fail if an out-of-memory error occurs during a format conversion. 4982** Only the following subset of interfaces are subject to out-of-memory 4983** errors: 4984** 4985** <ul> 4986** <li> sqlite3_column_blob() 4987** <li> sqlite3_column_text() 4988** <li> sqlite3_column_text16() 4989** <li> sqlite3_column_bytes() 4990** <li> sqlite3_column_bytes16() 4991** </ul> 4992** 4993** If an out-of-memory error occurs, then the return value from these 4994** routines is the same as if the column had contained an SQL NULL value. 4995** Valid SQL NULL returns can be distinguished from out-of-memory errors 4996** by invoking the [sqlite3_errcode()] immediately after the suspect 4997** return value is obtained and before any 4998** other SQLite interface is called on the same [database connection]. 4999*/ 5000const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 5001double sqlite3_column_double(sqlite3_stmt*, int iCol); 5002int sqlite3_column_int(sqlite3_stmt*, int iCol); 5003sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 5004const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 5005const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 5006sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 5007int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 5008int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 5009int sqlite3_column_type(sqlite3_stmt*, int iCol); 5010 5011/* 5012** CAPI3REF: Destroy A Prepared Statement Object 5013** DESTRUCTOR: sqlite3_stmt 5014** 5015** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 5016** ^If the most recent evaluation of the statement encountered no errors 5017** or if the statement is never been evaluated, then sqlite3_finalize() returns 5018** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 5019** sqlite3_finalize(S) returns the appropriate [error code] or 5020** [extended error code]. 5021** 5022** ^The sqlite3_finalize(S) routine can be called at any point during 5023** the life cycle of [prepared statement] S: 5024** before statement S is ever evaluated, after 5025** one or more calls to [sqlite3_reset()], or after any call 5026** to [sqlite3_step()] regardless of whether or not the statement has 5027** completed execution. 5028** 5029** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 5030** 5031** The application must finalize every [prepared statement] in order to avoid 5032** resource leaks. It is a grievous error for the application to try to use 5033** a prepared statement after it has been finalized. Any use of a prepared 5034** statement after it has been finalized can result in undefined and 5035** undesirable behavior such as segfaults and heap corruption. 5036*/ 5037int sqlite3_finalize(sqlite3_stmt *pStmt); 5038 5039/* 5040** CAPI3REF: Reset A Prepared Statement Object 5041** METHOD: sqlite3_stmt 5042** 5043** The sqlite3_reset() function is called to reset a [prepared statement] 5044** object back to its initial state, ready to be re-executed. 5045** ^Any SQL statement variables that had values bound to them using 5046** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 5047** Use [sqlite3_clear_bindings()] to reset the bindings. 5048** 5049** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 5050** back to the beginning of its program. 5051** 5052** ^If the most recent call to [sqlite3_step(S)] for the 5053** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 5054** or if [sqlite3_step(S)] has never before been called on S, 5055** then [sqlite3_reset(S)] returns [SQLITE_OK]. 5056** 5057** ^If the most recent call to [sqlite3_step(S)] for the 5058** [prepared statement] S indicated an error, then 5059** [sqlite3_reset(S)] returns an appropriate [error code]. 5060** 5061** ^The [sqlite3_reset(S)] interface does not change the values 5062** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 5063*/ 5064int sqlite3_reset(sqlite3_stmt *pStmt); 5065 5066/* 5067** CAPI3REF: Create Or Redefine SQL Functions 5068** KEYWORDS: {function creation routines} 5069** METHOD: sqlite3 5070** 5071** ^These functions (collectively known as "function creation routines") 5072** are used to add SQL functions or aggregates or to redefine the behavior 5073** of existing SQL functions or aggregates. The only differences between 5074** the three "sqlite3_create_function*" routines are the text encoding 5075** expected for the second parameter (the name of the function being 5076** created) and the presence or absence of a destructor callback for 5077** the application data pointer. Function sqlite3_create_window_function() 5078** is similar, but allows the user to supply the extra callback functions 5079** needed by [aggregate window functions]. 5080** 5081** ^The first parameter is the [database connection] to which the SQL 5082** function is to be added. ^If an application uses more than one database 5083** connection then application-defined SQL functions must be added 5084** to each database connection separately. 5085** 5086** ^The second parameter is the name of the SQL function to be created or 5087** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 5088** representation, exclusive of the zero-terminator. ^Note that the name 5089** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 5090** ^Any attempt to create a function with a longer name 5091** will result in [SQLITE_MISUSE] being returned. 5092** 5093** ^The third parameter (nArg) 5094** is the number of arguments that the SQL function or 5095** aggregate takes. ^If this parameter is -1, then the SQL function or 5096** aggregate may take any number of arguments between 0 and the limit 5097** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 5098** parameter is less than -1 or greater than 127 then the behavior is 5099** undefined. 5100** 5101** ^The fourth parameter, eTextRep, specifies what 5102** [SQLITE_UTF8 | text encoding] this SQL function prefers for 5103** its parameters. The application should set this parameter to 5104** [SQLITE_UTF16LE] if the function implementation invokes 5105** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 5106** implementation invokes [sqlite3_value_text16be()] on an input, or 5107** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 5108** otherwise. ^The same SQL function may be registered multiple times using 5109** different preferred text encodings, with different implementations for 5110** each encoding. 5111** ^When multiple implementations of the same function are available, SQLite 5112** will pick the one that involves the least amount of data conversion. 5113** 5114** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 5115** to signal that the function will always return the same result given 5116** the same inputs within a single SQL statement. Most SQL functions are 5117** deterministic. The built-in [random()] SQL function is an example of a 5118** function that is not deterministic. The SQLite query planner is able to 5119** perform additional optimizations on deterministic functions, so use 5120** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 5121** 5122** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY] 5123** flag, which if present prevents the function from being invoked from 5124** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions, 5125** index expressions, or the WHERE clause of partial indexes. 5126** 5127** <span style="background-color:#ffff90;"> 5128** For best security, the [SQLITE_DIRECTONLY] flag is recommended for 5129** all application-defined SQL functions that do not need to be 5130** used inside of triggers, view, CHECK constraints, or other elements of 5131** the database schema. This flags is especially recommended for SQL 5132** functions that have side effects or reveal internal application state. 5133** Without this flag, an attacker might be able to modify the schema of 5134** a database file to include invocations of the function with parameters 5135** chosen by the attacker, which the application will then execute when 5136** the database file is opened and read. 5137** </span> 5138** 5139** ^(The fifth parameter is an arbitrary pointer. The implementation of the 5140** function can gain access to this pointer using [sqlite3_user_data()].)^ 5141** 5142** ^The sixth, seventh and eighth parameters passed to the three 5143** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are 5144** pointers to C-language functions that implement the SQL function or 5145** aggregate. ^A scalar SQL function requires an implementation of the xFunc 5146** callback only; NULL pointers must be passed as the xStep and xFinal 5147** parameters. ^An aggregate SQL function requires an implementation of xStep 5148** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 5149** SQL function or aggregate, pass NULL pointers for all three function 5150** callbacks. 5151** 5152** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue 5153** and xInverse) passed to sqlite3_create_window_function are pointers to 5154** C-language callbacks that implement the new function. xStep and xFinal 5155** must both be non-NULL. xValue and xInverse may either both be NULL, in 5156** which case a regular aggregate function is created, or must both be 5157** non-NULL, in which case the new function may be used as either an aggregate 5158** or aggregate window function. More details regarding the implementation 5159** of aggregate window functions are 5160** [user-defined window functions|available here]. 5161** 5162** ^(If the final parameter to sqlite3_create_function_v2() or 5163** sqlite3_create_window_function() is not NULL, then it is destructor for 5164** the application data pointer. The destructor is invoked when the function 5165** is deleted, either by being overloaded or when the database connection 5166** closes.)^ ^The destructor is also invoked if the call to 5167** sqlite3_create_function_v2() fails. ^When the destructor callback is 5168** invoked, it is passed a single argument which is a copy of the application 5169** data pointer which was the fifth parameter to sqlite3_create_function_v2(). 5170** 5171** ^It is permitted to register multiple implementations of the same 5172** functions with the same name but with either differing numbers of 5173** arguments or differing preferred text encodings. ^SQLite will use 5174** the implementation that most closely matches the way in which the 5175** SQL function is used. ^A function implementation with a non-negative 5176** nArg parameter is a better match than a function implementation with 5177** a negative nArg. ^A function where the preferred text encoding 5178** matches the database encoding is a better 5179** match than a function where the encoding is different. 5180** ^A function where the encoding difference is between UTF16le and UTF16be 5181** is a closer match than a function where the encoding difference is 5182** between UTF8 and UTF16. 5183** 5184** ^Built-in functions may be overloaded by new application-defined functions. 5185** 5186** ^An application-defined function is permitted to call other 5187** SQLite interfaces. However, such calls must not 5188** close the database connection nor finalize or reset the prepared 5189** statement in which the function is running. 5190*/ 5191int sqlite3_create_function( 5192 sqlite3 *db, 5193 const char *zFunctionName, 5194 int nArg, 5195 int eTextRep, 5196 void *pApp, 5197 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5198 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5199 void (*xFinal)(sqlite3_context*) 5200); 5201int sqlite3_create_function16( 5202 sqlite3 *db, 5203 const void *zFunctionName, 5204 int nArg, 5205 int eTextRep, 5206 void *pApp, 5207 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5208 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5209 void (*xFinal)(sqlite3_context*) 5210); 5211int sqlite3_create_function_v2( 5212 sqlite3 *db, 5213 const char *zFunctionName, 5214 int nArg, 5215 int eTextRep, 5216 void *pApp, 5217 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5218 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5219 void (*xFinal)(sqlite3_context*), 5220 void(*xDestroy)(void*) 5221); 5222int sqlite3_create_window_function( 5223 sqlite3 *db, 5224 const char *zFunctionName, 5225 int nArg, 5226 int eTextRep, 5227 void *pApp, 5228 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5229 void (*xFinal)(sqlite3_context*), 5230 void (*xValue)(sqlite3_context*), 5231 void (*xInverse)(sqlite3_context*,int,sqlite3_value**), 5232 void(*xDestroy)(void*) 5233); 5234 5235/* 5236** CAPI3REF: Text Encodings 5237** 5238** These constant define integer codes that represent the various 5239** text encodings supported by SQLite. 5240*/ 5241#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 5242#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 5243#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 5244#define SQLITE_UTF16 4 /* Use native byte order */ 5245#define SQLITE_ANY 5 /* Deprecated */ 5246#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 5247 5248/* 5249** CAPI3REF: Function Flags 5250** 5251** These constants may be ORed together with the 5252** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 5253** to [sqlite3_create_function()], [sqlite3_create_function16()], or 5254** [sqlite3_create_function_v2()]. 5255** 5256** <dl> 5257** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd> 5258** The SQLITE_DETERMINISTIC flag means that the new function always gives 5259** the same output when the input parameters are the same. 5260** The [abs|abs() function] is deterministic, for example, but 5261** [randomblob|randomblob()] is not. Functions must 5262** be deterministic in order to be used in certain contexts such as 5263** with the WHERE clause of [partial indexes] or in [generated columns]. 5264** SQLite might also optimize deterministic functions by factoring them 5265** out of inner loops. 5266** </dd> 5267** 5268** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd> 5269** The SQLITE_DIRECTONLY flag means that the function may only be invoked 5270** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in 5271** schema structures such as [CHECK constraints], [DEFAULT clauses], 5272** [expression indexes], [partial indexes], or [generated columns]. 5273** The SQLITE_DIRECTONLY flags is a security feature which is recommended 5274** for all [application-defined SQL functions], and especially for functions 5275** that have side-effects or that could potentially leak sensitive 5276** information. 5277** </dd> 5278** 5279** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd> 5280** The SQLITE_INNOCUOUS flag means that the function is unlikely 5281** to cause problems even if misused. An innocuous function should have 5282** no side effects and should not depend on any values other than its 5283** input parameters. The [abs|abs() function] is an example of an 5284** innocuous function. 5285** The [load_extension() SQL function] is not innocuous because of its 5286** side effects. 5287** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not 5288** exactly the same. The [random|random() function] is an example of a 5289** function that is innocuous but not deterministic. 5290** <p>Some heightened security settings 5291** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF]) 5292** disable the use of SQL functions inside views and triggers and in 5293** schema structures such as [CHECK constraints], [DEFAULT clauses], 5294** [expression indexes], [partial indexes], and [generated columns] unless 5295** the function is tagged with SQLITE_INNOCUOUS. Most built-in functions 5296** are innocuous. Developers are advised to avoid using the 5297** SQLITE_INNOCUOUS flag for application-defined functions unless the 5298** function has been carefully audited and found to be free of potentially 5299** security-adverse side-effects and information-leaks. 5300** </dd> 5301** 5302** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd> 5303** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call 5304** [sqlite3_value_subtype()] to inspect the sub-types of its arguments. 5305** Specifying this flag makes no difference for scalar or aggregate user 5306** functions. However, if it is not specified for a user-defined window 5307** function, then any sub-types belonging to arguments passed to the window 5308** function may be discarded before the window function is called (i.e. 5309** sqlite3_value_subtype() will always return 0). 5310** </dd> 5311** </dl> 5312*/ 5313#define SQLITE_DETERMINISTIC 0x000000800 5314#define SQLITE_DIRECTONLY 0x000080000 5315#define SQLITE_SUBTYPE 0x000100000 5316#define SQLITE_INNOCUOUS 0x000200000 5317 5318/* 5319** CAPI3REF: Deprecated Functions 5320** DEPRECATED 5321** 5322** These functions are [deprecated]. In order to maintain 5323** backwards compatibility with older code, these functions continue 5324** to be supported. However, new applications should avoid 5325** the use of these functions. To encourage programmers to avoid 5326** these functions, we will not explain what they do. 5327*/ 5328#ifndef SQLITE_OMIT_DEPRECATED 5329SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 5330SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 5331SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 5332SQLITE_DEPRECATED int sqlite3_global_recover(void); 5333SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 5334SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 5335 void*,sqlite3_int64); 5336#endif 5337 5338/* 5339** CAPI3REF: Obtaining SQL Values 5340** METHOD: sqlite3_value 5341** 5342** <b>Summary:</b> 5343** <blockquote><table border=0 cellpadding=0 cellspacing=0> 5344** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 5345** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 5346** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 5347** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 5348** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 5349** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 5350** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 5351** the native byteorder 5352** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 5353** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 5354** <tr><td> <td> <td> 5355** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 5356** or a UTF-8 TEXT in bytes 5357** <tr><td><b>sqlite3_value_bytes16 </b> 5358** <td>→ <td>Size of UTF-16 5359** TEXT in bytes 5360** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 5361** datatype of the value 5362** <tr><td><b>sqlite3_value_numeric_type </b> 5363** <td>→ <td>Best numeric datatype of the value 5364** <tr><td><b>sqlite3_value_nochange </b> 5365** <td>→ <td>True if the column is unchanged in an UPDATE 5366** against a virtual table. 5367** <tr><td><b>sqlite3_value_frombind </b> 5368** <td>→ <td>True if value originated from a [bound parameter] 5369** </table></blockquote> 5370** 5371** <b>Details:</b> 5372** 5373** These routines extract type, size, and content information from 5374** [protected sqlite3_value] objects. Protected sqlite3_value objects 5375** are used to pass parameter information into the functions that 5376** implement [application-defined SQL functions] and [virtual tables]. 5377** 5378** These routines work only with [protected sqlite3_value] objects. 5379** Any attempt to use these routines on an [unprotected sqlite3_value] 5380** is not threadsafe. 5381** 5382** ^These routines work just like the corresponding [column access functions] 5383** except that these routines take a single [protected sqlite3_value] object 5384** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 5385** 5386** ^The sqlite3_value_text16() interface extracts a UTF-16 string 5387** in the native byte-order of the host machine. ^The 5388** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 5389** extract UTF-16 strings as big-endian and little-endian respectively. 5390** 5391** ^If [sqlite3_value] object V was initialized 5392** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 5393** and if X and Y are strings that compare equal according to strcmp(X,Y), 5394** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 5395** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 5396** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5397** 5398** ^(The sqlite3_value_type(V) interface returns the 5399** [SQLITE_INTEGER | datatype code] for the initial datatype of the 5400** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 5401** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 5402** Other interfaces might change the datatype for an sqlite3_value object. 5403** For example, if the datatype is initially SQLITE_INTEGER and 5404** sqlite3_value_text(V) is called to extract a text value for that 5405** integer, then subsequent calls to sqlite3_value_type(V) might return 5406** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 5407** occurs is undefined and may change from one release of SQLite to the next. 5408** 5409** ^(The sqlite3_value_numeric_type() interface attempts to apply 5410** numeric affinity to the value. This means that an attempt is 5411** made to convert the value to an integer or floating point. If 5412** such a conversion is possible without loss of information (in other 5413** words, if the value is a string that looks like a number) 5414** then the conversion is performed. Otherwise no conversion occurs. 5415** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 5416** 5417** ^Within the [xUpdate] method of a [virtual table], the 5418** sqlite3_value_nochange(X) interface returns true if and only if 5419** the column corresponding to X is unchanged by the UPDATE operation 5420** that the xUpdate method call was invoked to implement and if 5421** and the prior [xColumn] method call that was invoked to extracted 5422** the value for that column returned without setting a result (probably 5423** because it queried [sqlite3_vtab_nochange()] and found that the column 5424** was unchanging). ^Within an [xUpdate] method, any value for which 5425** sqlite3_value_nochange(X) is true will in all other respects appear 5426** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 5427** than within an [xUpdate] method call for an UPDATE statement, then 5428** the return value is arbitrary and meaningless. 5429** 5430** ^The sqlite3_value_frombind(X) interface returns non-zero if the 5431** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()] 5432** interfaces. ^If X comes from an SQL literal value, or a table column, 5433** or an expression, then sqlite3_value_frombind(X) returns zero. 5434** 5435** Please pay particular attention to the fact that the pointer returned 5436** from [sqlite3_value_blob()], [sqlite3_value_text()], or 5437** [sqlite3_value_text16()] can be invalidated by a subsequent call to 5438** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 5439** or [sqlite3_value_text16()]. 5440** 5441** These routines must be called from the same thread as 5442** the SQL function that supplied the [sqlite3_value*] parameters. 5443** 5444** As long as the input parameter is correct, these routines can only 5445** fail if an out-of-memory error occurs during a format conversion. 5446** Only the following subset of interfaces are subject to out-of-memory 5447** errors: 5448** 5449** <ul> 5450** <li> sqlite3_value_blob() 5451** <li> sqlite3_value_text() 5452** <li> sqlite3_value_text16() 5453** <li> sqlite3_value_text16le() 5454** <li> sqlite3_value_text16be() 5455** <li> sqlite3_value_bytes() 5456** <li> sqlite3_value_bytes16() 5457** </ul> 5458** 5459** If an out-of-memory error occurs, then the return value from these 5460** routines is the same as if the column had contained an SQL NULL value. 5461** Valid SQL NULL returns can be distinguished from out-of-memory errors 5462** by invoking the [sqlite3_errcode()] immediately after the suspect 5463** return value is obtained and before any 5464** other SQLite interface is called on the same [database connection]. 5465*/ 5466const void *sqlite3_value_blob(sqlite3_value*); 5467double sqlite3_value_double(sqlite3_value*); 5468int sqlite3_value_int(sqlite3_value*); 5469sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 5470void *sqlite3_value_pointer(sqlite3_value*, const char*); 5471const unsigned char *sqlite3_value_text(sqlite3_value*); 5472const void *sqlite3_value_text16(sqlite3_value*); 5473const void *sqlite3_value_text16le(sqlite3_value*); 5474const void *sqlite3_value_text16be(sqlite3_value*); 5475int sqlite3_value_bytes(sqlite3_value*); 5476int sqlite3_value_bytes16(sqlite3_value*); 5477int sqlite3_value_type(sqlite3_value*); 5478int sqlite3_value_numeric_type(sqlite3_value*); 5479int sqlite3_value_nochange(sqlite3_value*); 5480int sqlite3_value_frombind(sqlite3_value*); 5481 5482/* 5483** CAPI3REF: Finding The Subtype Of SQL Values 5484** METHOD: sqlite3_value 5485** 5486** The sqlite3_value_subtype(V) function returns the subtype for 5487** an [application-defined SQL function] argument V. The subtype 5488** information can be used to pass a limited amount of context from 5489** one SQL function to another. Use the [sqlite3_result_subtype()] 5490** routine to set the subtype for the return value of an SQL function. 5491*/ 5492unsigned int sqlite3_value_subtype(sqlite3_value*); 5493 5494/* 5495** CAPI3REF: Copy And Free SQL Values 5496** METHOD: sqlite3_value 5497** 5498** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 5499** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 5500** is a [protected sqlite3_value] object even if the input is not. 5501** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 5502** memory allocation fails. 5503** 5504** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 5505** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 5506** then sqlite3_value_free(V) is a harmless no-op. 5507*/ 5508sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 5509void sqlite3_value_free(sqlite3_value*); 5510 5511/* 5512** CAPI3REF: Obtain Aggregate Function Context 5513** METHOD: sqlite3_context 5514** 5515** Implementations of aggregate SQL functions use this 5516** routine to allocate memory for storing their state. 5517** 5518** ^The first time the sqlite3_aggregate_context(C,N) routine is called 5519** for a particular aggregate function, SQLite allocates 5520** N bytes of memory, zeroes out that memory, and returns a pointer 5521** to the new memory. ^On second and subsequent calls to 5522** sqlite3_aggregate_context() for the same aggregate function instance, 5523** the same buffer is returned. Sqlite3_aggregate_context() is normally 5524** called once for each invocation of the xStep callback and then one 5525** last time when the xFinal callback is invoked. ^(When no rows match 5526** an aggregate query, the xStep() callback of the aggregate function 5527** implementation is never called and xFinal() is called exactly once. 5528** In those cases, sqlite3_aggregate_context() might be called for the 5529** first time from within xFinal().)^ 5530** 5531** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 5532** when first called if N is less than or equal to zero or if a memory 5533** allocate error occurs. 5534** 5535** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 5536** determined by the N parameter on first successful call. Changing the 5537** value of N in any subsequent call to sqlite3_aggregate_context() within 5538** the same aggregate function instance will not resize the memory 5539** allocation.)^ Within the xFinal callback, it is customary to set 5540** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 5541** pointless memory allocations occur. 5542** 5543** ^SQLite automatically frees the memory allocated by 5544** sqlite3_aggregate_context() when the aggregate query concludes. 5545** 5546** The first parameter must be a copy of the 5547** [sqlite3_context | SQL function context] that is the first parameter 5548** to the xStep or xFinal callback routine that implements the aggregate 5549** function. 5550** 5551** This routine must be called from the same thread in which 5552** the aggregate SQL function is running. 5553*/ 5554void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 5555 5556/* 5557** CAPI3REF: User Data For Functions 5558** METHOD: sqlite3_context 5559** 5560** ^The sqlite3_user_data() interface returns a copy of 5561** the pointer that was the pUserData parameter (the 5th parameter) 5562** of the [sqlite3_create_function()] 5563** and [sqlite3_create_function16()] routines that originally 5564** registered the application defined function. 5565** 5566** This routine must be called from the same thread in which 5567** the application-defined function is running. 5568*/ 5569void *sqlite3_user_data(sqlite3_context*); 5570 5571/* 5572** CAPI3REF: Database Connection For Functions 5573** METHOD: sqlite3_context 5574** 5575** ^The sqlite3_context_db_handle() interface returns a copy of 5576** the pointer to the [database connection] (the 1st parameter) 5577** of the [sqlite3_create_function()] 5578** and [sqlite3_create_function16()] routines that originally 5579** registered the application defined function. 5580*/ 5581sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 5582 5583/* 5584** CAPI3REF: Function Auxiliary Data 5585** METHOD: sqlite3_context 5586** 5587** These functions may be used by (non-aggregate) SQL functions to 5588** associate metadata with argument values. If the same value is passed to 5589** multiple invocations of the same SQL function during query execution, under 5590** some circumstances the associated metadata may be preserved. An example 5591** of where this might be useful is in a regular-expression matching 5592** function. The compiled version of the regular expression can be stored as 5593** metadata associated with the pattern string. 5594** Then as long as the pattern string remains the same, 5595** the compiled regular expression can be reused on multiple 5596** invocations of the same function. 5597** 5598** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 5599** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 5600** value to the application-defined function. ^N is zero for the left-most 5601** function argument. ^If there is no metadata 5602** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 5603** returns a NULL pointer. 5604** 5605** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 5606** argument of the application-defined function. ^Subsequent 5607** calls to sqlite3_get_auxdata(C,N) return P from the most recent 5608** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5609** NULL if the metadata has been discarded. 5610** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5611** SQLite will invoke the destructor function X with parameter P exactly 5612** once, when the metadata is discarded. 5613** SQLite is free to discard the metadata at any time, including: <ul> 5614** <li> ^(when the corresponding function parameter changes)^, or 5615** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5616** SQL statement)^, or 5617** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5618** parameter)^, or 5619** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5620** allocation error occurs.)^ </ul> 5621** 5622** Note the last bullet in particular. The destructor X in 5623** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5624** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5625** should be called near the end of the function implementation and the 5626** function implementation should not make any use of P after 5627** sqlite3_set_auxdata() has been called. 5628** 5629** ^(In practice, metadata is preserved between function calls for 5630** function parameters that are compile-time constants, including literal 5631** values and [parameters] and expressions composed from the same.)^ 5632** 5633** The value of the N parameter to these interfaces should be non-negative. 5634** Future enhancements may make use of negative N values to define new 5635** kinds of function caching behavior. 5636** 5637** These routines must be called from the same thread in which 5638** the SQL function is running. 5639*/ 5640void *sqlite3_get_auxdata(sqlite3_context*, int N); 5641void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5642 5643 5644/* 5645** CAPI3REF: Constants Defining Special Destructor Behavior 5646** 5647** These are special values for the destructor that is passed in as the 5648** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5649** argument is SQLITE_STATIC, it means that the content pointer is constant 5650** and will never change. It does not need to be destroyed. ^The 5651** SQLITE_TRANSIENT value means that the content will likely change in 5652** the near future and that SQLite should make its own private copy of 5653** the content before returning. 5654** 5655** The typedef is necessary to work around problems in certain 5656** C++ compilers. 5657*/ 5658typedef void (*sqlite3_destructor_type)(void*); 5659#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5660#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5661 5662/* 5663** CAPI3REF: Setting The Result Of An SQL Function 5664** METHOD: sqlite3_context 5665** 5666** These routines are used by the xFunc or xFinal callbacks that 5667** implement SQL functions and aggregates. See 5668** [sqlite3_create_function()] and [sqlite3_create_function16()] 5669** for additional information. 5670** 5671** These functions work very much like the [parameter binding] family of 5672** functions used to bind values to host parameters in prepared statements. 5673** Refer to the [SQL parameter] documentation for additional information. 5674** 5675** ^The sqlite3_result_blob() interface sets the result from 5676** an application-defined function to be the BLOB whose content is pointed 5677** to by the second parameter and which is N bytes long where N is the 5678** third parameter. 5679** 5680** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5681** interfaces set the result of the application-defined function to be 5682** a BLOB containing all zero bytes and N bytes in size. 5683** 5684** ^The sqlite3_result_double() interface sets the result from 5685** an application-defined function to be a floating point value specified 5686** by its 2nd argument. 5687** 5688** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5689** cause the implemented SQL function to throw an exception. 5690** ^SQLite uses the string pointed to by the 5691** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5692** as the text of an error message. ^SQLite interprets the error 5693** message string from sqlite3_result_error() as UTF-8. ^SQLite 5694** interprets the string from sqlite3_result_error16() as UTF-16 using 5695** the same [byte-order determination rules] as [sqlite3_bind_text16()]. 5696** ^If the third parameter to sqlite3_result_error() 5697** or sqlite3_result_error16() is negative then SQLite takes as the error 5698** message all text up through the first zero character. 5699** ^If the third parameter to sqlite3_result_error() or 5700** sqlite3_result_error16() is non-negative then SQLite takes that many 5701** bytes (not characters) from the 2nd parameter as the error message. 5702** ^The sqlite3_result_error() and sqlite3_result_error16() 5703** routines make a private copy of the error message text before 5704** they return. Hence, the calling function can deallocate or 5705** modify the text after they return without harm. 5706** ^The sqlite3_result_error_code() function changes the error code 5707** returned by SQLite as a result of an error in a function. ^By default, 5708** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5709** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5710** 5711** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5712** error indicating that a string or BLOB is too long to represent. 5713** 5714** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5715** error indicating that a memory allocation failed. 5716** 5717** ^The sqlite3_result_int() interface sets the return value 5718** of the application-defined function to be the 32-bit signed integer 5719** value given in the 2nd argument. 5720** ^The sqlite3_result_int64() interface sets the return value 5721** of the application-defined function to be the 64-bit signed integer 5722** value given in the 2nd argument. 5723** 5724** ^The sqlite3_result_null() interface sets the return value 5725** of the application-defined function to be NULL. 5726** 5727** ^The sqlite3_result_text(), sqlite3_result_text16(), 5728** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5729** set the return value of the application-defined function to be 5730** a text string which is represented as UTF-8, UTF-16 native byte order, 5731** UTF-16 little endian, or UTF-16 big endian, respectively. 5732** ^The sqlite3_result_text64() interface sets the return value of an 5733** application-defined function to be a text string in an encoding 5734** specified by the fifth (and last) parameter, which must be one 5735** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5736** ^SQLite takes the text result from the application from 5737** the 2nd parameter of the sqlite3_result_text* interfaces. 5738** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5739** is negative, then SQLite takes result text from the 2nd parameter 5740** through the first zero character. 5741** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5742** is non-negative, then as many bytes (not characters) of the text 5743** pointed to by the 2nd parameter are taken as the application-defined 5744** function result. If the 3rd parameter is non-negative, then it 5745** must be the byte offset into the string where the NUL terminator would 5746** appear if the string where NUL terminated. If any NUL characters occur 5747** in the string at a byte offset that is less than the value of the 3rd 5748** parameter, then the resulting string will contain embedded NULs and the 5749** result of expressions operating on strings with embedded NULs is undefined. 5750** ^If the 4th parameter to the sqlite3_result_text* interfaces 5751** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5752** function as the destructor on the text or BLOB result when it has 5753** finished using that result. 5754** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5755** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5756** assumes that the text or BLOB result is in constant space and does not 5757** copy the content of the parameter nor call a destructor on the content 5758** when it has finished using that result. 5759** ^If the 4th parameter to the sqlite3_result_text* interfaces 5760** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5761** then SQLite makes a copy of the result into space obtained 5762** from [sqlite3_malloc()] before it returns. 5763** 5764** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and 5765** sqlite3_result_text16be() routines, and for sqlite3_result_text64() 5766** when the encoding is not UTF8, if the input UTF16 begins with a 5767** byte-order mark (BOM, U+FEFF) then the BOM is removed from the 5768** string and the rest of the string is interpreted according to the 5769** byte-order specified by the BOM. ^The byte-order specified by 5770** the BOM at the beginning of the text overrides the byte-order 5771** specified by the interface procedure. ^So, for example, if 5772** sqlite3_result_text16le() is invoked with text that begins 5773** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the 5774** first two bytes of input are skipped and the remaining input 5775** is interpreted as UTF16BE text. 5776** 5777** ^For UTF16 input text to the sqlite3_result_text16(), 5778** sqlite3_result_text16be(), sqlite3_result_text16le(), and 5779** sqlite3_result_text64() routines, if the text contains invalid 5780** UTF16 characters, the invalid characters might be converted 5781** into the unicode replacement character, U+FFFD. 5782** 5783** ^The sqlite3_result_value() interface sets the result of 5784** the application-defined function to be a copy of the 5785** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5786** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5787** so that the [sqlite3_value] specified in the parameter may change or 5788** be deallocated after sqlite3_result_value() returns without harm. 5789** ^A [protected sqlite3_value] object may always be used where an 5790** [unprotected sqlite3_value] object is required, so either 5791** kind of [sqlite3_value] object can be used with this interface. 5792** 5793** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5794** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5795** also associates the host-language pointer P or type T with that 5796** NULL value such that the pointer can be retrieved within an 5797** [application-defined SQL function] using [sqlite3_value_pointer()]. 5798** ^If the D parameter is not NULL, then it is a pointer to a destructor 5799** for the P parameter. ^SQLite invokes D with P as its only argument 5800** when SQLite is finished with P. The T parameter should be a static 5801** string and preferably a string literal. The sqlite3_result_pointer() 5802** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5803** 5804** If these routines are called from within the different thread 5805** than the one containing the application-defined function that received 5806** the [sqlite3_context] pointer, the results are undefined. 5807*/ 5808void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5809void sqlite3_result_blob64(sqlite3_context*,const void*, 5810 sqlite3_uint64,void(*)(void*)); 5811void sqlite3_result_double(sqlite3_context*, double); 5812void sqlite3_result_error(sqlite3_context*, const char*, int); 5813void sqlite3_result_error16(sqlite3_context*, const void*, int); 5814void sqlite3_result_error_toobig(sqlite3_context*); 5815void sqlite3_result_error_nomem(sqlite3_context*); 5816void sqlite3_result_error_code(sqlite3_context*, int); 5817void sqlite3_result_int(sqlite3_context*, int); 5818void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5819void sqlite3_result_null(sqlite3_context*); 5820void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5821void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5822 void(*)(void*), unsigned char encoding); 5823void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5824void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5825void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5826void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5827void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5828void sqlite3_result_zeroblob(sqlite3_context*, int n); 5829int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5830 5831 5832/* 5833** CAPI3REF: Setting The Subtype Of An SQL Function 5834** METHOD: sqlite3_context 5835** 5836** The sqlite3_result_subtype(C,T) function causes the subtype of 5837** the result from the [application-defined SQL function] with 5838** [sqlite3_context] C to be the value T. Only the lower 8 bits 5839** of the subtype T are preserved in current versions of SQLite; 5840** higher order bits are discarded. 5841** The number of subtype bytes preserved by SQLite might increase 5842** in future releases of SQLite. 5843*/ 5844void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5845 5846/* 5847** CAPI3REF: Define New Collating Sequences 5848** METHOD: sqlite3 5849** 5850** ^These functions add, remove, or modify a [collation] associated 5851** with the [database connection] specified as the first argument. 5852** 5853** ^The name of the collation is a UTF-8 string 5854** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5855** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5856** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5857** considered to be the same name. 5858** 5859** ^(The third argument (eTextRep) must be one of the constants: 5860** <ul> 5861** <li> [SQLITE_UTF8], 5862** <li> [SQLITE_UTF16LE], 5863** <li> [SQLITE_UTF16BE], 5864** <li> [SQLITE_UTF16], or 5865** <li> [SQLITE_UTF16_ALIGNED]. 5866** </ul>)^ 5867** ^The eTextRep argument determines the encoding of strings passed 5868** to the collating function callback, xCompare. 5869** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5870** force strings to be UTF16 with native byte order. 5871** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5872** on an even byte address. 5873** 5874** ^The fourth argument, pArg, is an application data pointer that is passed 5875** through as the first argument to the collating function callback. 5876** 5877** ^The fifth argument, xCompare, is a pointer to the collating function. 5878** ^Multiple collating functions can be registered using the same name but 5879** with different eTextRep parameters and SQLite will use whichever 5880** function requires the least amount of data transformation. 5881** ^If the xCompare argument is NULL then the collating function is 5882** deleted. ^When all collating functions having the same name are deleted, 5883** that collation is no longer usable. 5884** 5885** ^The collating function callback is invoked with a copy of the pArg 5886** application data pointer and with two strings in the encoding specified 5887** by the eTextRep argument. The two integer parameters to the collating 5888** function callback are the length of the two strings, in bytes. The collating 5889** function must return an integer that is negative, zero, or positive 5890** if the first string is less than, equal to, or greater than the second, 5891** respectively. A collating function must always return the same answer 5892** given the same inputs. If two or more collating functions are registered 5893** to the same collation name (using different eTextRep values) then all 5894** must give an equivalent answer when invoked with equivalent strings. 5895** The collating function must obey the following properties for all 5896** strings A, B, and C: 5897** 5898** <ol> 5899** <li> If A==B then B==A. 5900** <li> If A==B and B==C then A==C. 5901** <li> If A<B THEN B>A. 5902** <li> If A<B and B<C then A<C. 5903** </ol> 5904** 5905** If a collating function fails any of the above constraints and that 5906** collating function is registered and used, then the behavior of SQLite 5907** is undefined. 5908** 5909** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5910** with the addition that the xDestroy callback is invoked on pArg when 5911** the collating function is deleted. 5912** ^Collating functions are deleted when they are overridden by later 5913** calls to the collation creation functions or when the 5914** [database connection] is closed using [sqlite3_close()]. 5915** 5916** ^The xDestroy callback is <u>not</u> called if the 5917** sqlite3_create_collation_v2() function fails. Applications that invoke 5918** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5919** check the return code and dispose of the application data pointer 5920** themselves rather than expecting SQLite to deal with it for them. 5921** This is different from every other SQLite interface. The inconsistency 5922** is unfortunate but cannot be changed without breaking backwards 5923** compatibility. 5924** 5925** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5926*/ 5927int sqlite3_create_collation( 5928 sqlite3*, 5929 const char *zName, 5930 int eTextRep, 5931 void *pArg, 5932 int(*xCompare)(void*,int,const void*,int,const void*) 5933); 5934int sqlite3_create_collation_v2( 5935 sqlite3*, 5936 const char *zName, 5937 int eTextRep, 5938 void *pArg, 5939 int(*xCompare)(void*,int,const void*,int,const void*), 5940 void(*xDestroy)(void*) 5941); 5942int sqlite3_create_collation16( 5943 sqlite3*, 5944 const void *zName, 5945 int eTextRep, 5946 void *pArg, 5947 int(*xCompare)(void*,int,const void*,int,const void*) 5948); 5949 5950/* 5951** CAPI3REF: Collation Needed Callbacks 5952** METHOD: sqlite3 5953** 5954** ^To avoid having to register all collation sequences before a database 5955** can be used, a single callback function may be registered with the 5956** [database connection] to be invoked whenever an undefined collation 5957** sequence is required. 5958** 5959** ^If the function is registered using the sqlite3_collation_needed() API, 5960** then it is passed the names of undefined collation sequences as strings 5961** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5962** the names are passed as UTF-16 in machine native byte order. 5963** ^A call to either function replaces the existing collation-needed callback. 5964** 5965** ^(When the callback is invoked, the first argument passed is a copy 5966** of the second argument to sqlite3_collation_needed() or 5967** sqlite3_collation_needed16(). The second argument is the database 5968** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5969** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5970** sequence function required. The fourth parameter is the name of the 5971** required collation sequence.)^ 5972** 5973** The callback function should register the desired collation using 5974** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5975** [sqlite3_create_collation_v2()]. 5976*/ 5977int sqlite3_collation_needed( 5978 sqlite3*, 5979 void*, 5980 void(*)(void*,sqlite3*,int eTextRep,const char*) 5981); 5982int sqlite3_collation_needed16( 5983 sqlite3*, 5984 void*, 5985 void(*)(void*,sqlite3*,int eTextRep,const void*) 5986); 5987 5988#ifdef SQLITE_ENABLE_CEROD 5989/* 5990** Specify the activation key for a CEROD database. Unless 5991** activated, none of the CEROD routines will work. 5992*/ 5993void sqlite3_activate_cerod( 5994 const char *zPassPhrase /* Activation phrase */ 5995); 5996#endif 5997 5998/* 5999** CAPI3REF: Suspend Execution For A Short Time 6000** 6001** The sqlite3_sleep() function causes the current thread to suspend execution 6002** for at least a number of milliseconds specified in its parameter. 6003** 6004** If the operating system does not support sleep requests with 6005** millisecond time resolution, then the time will be rounded up to 6006** the nearest second. The number of milliseconds of sleep actually 6007** requested from the operating system is returned. 6008** 6009** ^SQLite implements this interface by calling the xSleep() 6010** method of the default [sqlite3_vfs] object. If the xSleep() method 6011** of the default VFS is not implemented correctly, or not implemented at 6012** all, then the behavior of sqlite3_sleep() may deviate from the description 6013** in the previous paragraphs. 6014*/ 6015int sqlite3_sleep(int); 6016 6017/* 6018** CAPI3REF: Name Of The Folder Holding Temporary Files 6019** 6020** ^(If this global variable is made to point to a string which is 6021** the name of a folder (a.k.a. directory), then all temporary files 6022** created by SQLite when using a built-in [sqlite3_vfs | VFS] 6023** will be placed in that directory.)^ ^If this variable 6024** is a NULL pointer, then SQLite performs a search for an appropriate 6025** temporary file directory. 6026** 6027** Applications are strongly discouraged from using this global variable. 6028** It is required to set a temporary folder on Windows Runtime (WinRT). 6029** But for all other platforms, it is highly recommended that applications 6030** neither read nor write this variable. This global variable is a relic 6031** that exists for backwards compatibility of legacy applications and should 6032** be avoided in new projects. 6033** 6034** It is not safe to read or modify this variable in more than one 6035** thread at a time. It is not safe to read or modify this variable 6036** if a [database connection] is being used at the same time in a separate 6037** thread. 6038** It is intended that this variable be set once 6039** as part of process initialization and before any SQLite interface 6040** routines have been called and that this variable remain unchanged 6041** thereafter. 6042** 6043** ^The [temp_store_directory pragma] may modify this variable and cause 6044** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6045** the [temp_store_directory pragma] always assumes that any string 6046** that this variable points to is held in memory obtained from 6047** [sqlite3_malloc] and the pragma may attempt to free that memory 6048** using [sqlite3_free]. 6049** Hence, if this variable is modified directly, either it should be 6050** made NULL or made to point to memory obtained from [sqlite3_malloc] 6051** or else the use of the [temp_store_directory pragma] should be avoided. 6052** Except when requested by the [temp_store_directory pragma], SQLite 6053** does not free the memory that sqlite3_temp_directory points to. If 6054** the application wants that memory to be freed, it must do 6055** so itself, taking care to only do so after all [database connection] 6056** objects have been destroyed. 6057** 6058** <b>Note to Windows Runtime users:</b> The temporary directory must be set 6059** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 6060** features that require the use of temporary files may fail. Here is an 6061** example of how to do this using C++ with the Windows Runtime: 6062** 6063** <blockquote><pre> 6064** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 6065** TemporaryFolder->Path->Data(); 6066** char zPathBuf[MAX_PATH + 1]; 6067** memset(zPathBuf, 0, sizeof(zPathBuf)); 6068** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 6069** NULL, NULL); 6070** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 6071** </pre></blockquote> 6072*/ 6073SQLITE_EXTERN char *sqlite3_temp_directory; 6074 6075/* 6076** CAPI3REF: Name Of The Folder Holding Database Files 6077** 6078** ^(If this global variable is made to point to a string which is 6079** the name of a folder (a.k.a. directory), then all database files 6080** specified with a relative pathname and created or accessed by 6081** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 6082** to be relative to that directory.)^ ^If this variable is a NULL 6083** pointer, then SQLite assumes that all database files specified 6084** with a relative pathname are relative to the current directory 6085** for the process. Only the windows VFS makes use of this global 6086** variable; it is ignored by the unix VFS. 6087** 6088** Changing the value of this variable while a database connection is 6089** open can result in a corrupt database. 6090** 6091** It is not safe to read or modify this variable in more than one 6092** thread at a time. It is not safe to read or modify this variable 6093** if a [database connection] is being used at the same time in a separate 6094** thread. 6095** It is intended that this variable be set once 6096** as part of process initialization and before any SQLite interface 6097** routines have been called and that this variable remain unchanged 6098** thereafter. 6099** 6100** ^The [data_store_directory pragma] may modify this variable and cause 6101** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6102** the [data_store_directory pragma] always assumes that any string 6103** that this variable points to is held in memory obtained from 6104** [sqlite3_malloc] and the pragma may attempt to free that memory 6105** using [sqlite3_free]. 6106** Hence, if this variable is modified directly, either it should be 6107** made NULL or made to point to memory obtained from [sqlite3_malloc] 6108** or else the use of the [data_store_directory pragma] should be avoided. 6109*/ 6110SQLITE_EXTERN char *sqlite3_data_directory; 6111 6112/* 6113** CAPI3REF: Win32 Specific Interface 6114** 6115** These interfaces are available only on Windows. The 6116** [sqlite3_win32_set_directory] interface is used to set the value associated 6117** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to 6118** zValue, depending on the value of the type parameter. The zValue parameter 6119** should be NULL to cause the previous value to be freed via [sqlite3_free]; 6120** a non-NULL value will be copied into memory obtained from [sqlite3_malloc] 6121** prior to being used. The [sqlite3_win32_set_directory] interface returns 6122** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported, 6123** or [SQLITE_NOMEM] if memory could not be allocated. The value of the 6124** [sqlite3_data_directory] variable is intended to act as a replacement for 6125** the current directory on the sub-platforms of Win32 where that concept is 6126** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and 6127** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the 6128** sqlite3_win32_set_directory interface except the string parameter must be 6129** UTF-8 or UTF-16, respectively. 6130*/ 6131int sqlite3_win32_set_directory( 6132 unsigned long type, /* Identifier for directory being set or reset */ 6133 void *zValue /* New value for directory being set or reset */ 6134); 6135int sqlite3_win32_set_directory8(unsigned long type, const char *zValue); 6136int sqlite3_win32_set_directory16(unsigned long type, const void *zValue); 6137 6138/* 6139** CAPI3REF: Win32 Directory Types 6140** 6141** These macros are only available on Windows. They define the allowed values 6142** for the type argument to the [sqlite3_win32_set_directory] interface. 6143*/ 6144#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1 6145#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2 6146 6147/* 6148** CAPI3REF: Test For Auto-Commit Mode 6149** KEYWORDS: {autocommit mode} 6150** METHOD: sqlite3 6151** 6152** ^The sqlite3_get_autocommit() interface returns non-zero or 6153** zero if the given database connection is or is not in autocommit mode, 6154** respectively. ^Autocommit mode is on by default. 6155** ^Autocommit mode is disabled by a [BEGIN] statement. 6156** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 6157** 6158** If certain kinds of errors occur on a statement within a multi-statement 6159** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 6160** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 6161** transaction might be rolled back automatically. The only way to 6162** find out whether SQLite automatically rolled back the transaction after 6163** an error is to use this function. 6164** 6165** If another thread changes the autocommit status of the database 6166** connection while this routine is running, then the return value 6167** is undefined. 6168*/ 6169int sqlite3_get_autocommit(sqlite3*); 6170 6171/* 6172** CAPI3REF: Find The Database Handle Of A Prepared Statement 6173** METHOD: sqlite3_stmt 6174** 6175** ^The sqlite3_db_handle interface returns the [database connection] handle 6176** to which a [prepared statement] belongs. ^The [database connection] 6177** returned by sqlite3_db_handle is the same [database connection] 6178** that was the first argument 6179** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 6180** create the statement in the first place. 6181*/ 6182sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 6183 6184/* 6185** CAPI3REF: Return The Filename For A Database Connection 6186** METHOD: sqlite3 6187** 6188** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename 6189** associated with database N of connection D. 6190** ^If there is no attached database N on the database 6191** connection D, or if database N is a temporary or in-memory database, then 6192** this function will return either a NULL pointer or an empty string. 6193** 6194** ^The string value returned by this routine is owned and managed by 6195** the database connection. ^The value will be valid until the database N 6196** is [DETACH]-ed or until the database connection closes. 6197** 6198** ^The filename returned by this function is the output of the 6199** xFullPathname method of the [VFS]. ^In other words, the filename 6200** will be an absolute pathname, even if the filename used 6201** to open the database originally was a URI or relative pathname. 6202** 6203** If the filename pointer returned by this routine is not NULL, then it 6204** can be used as the filename input parameter to these routines: 6205** <ul> 6206** <li> [sqlite3_uri_parameter()] 6207** <li> [sqlite3_uri_boolean()] 6208** <li> [sqlite3_uri_int64()] 6209** <li> [sqlite3_filename_database()] 6210** <li> [sqlite3_filename_journal()] 6211** <li> [sqlite3_filename_wal()] 6212** </ul> 6213*/ 6214const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 6215 6216/* 6217** CAPI3REF: Determine if a database is read-only 6218** METHOD: sqlite3 6219** 6220** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 6221** of connection D is read-only, 0 if it is read/write, or -1 if N is not 6222** the name of a database on connection D. 6223*/ 6224int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 6225 6226/* 6227** CAPI3REF: Determine the transaction state of a database 6228** METHOD: sqlite3 6229** 6230** ^The sqlite3_txn_state(D,S) interface returns the current 6231** [transaction state] of schema S in database connection D. ^If S is NULL, 6232** then the highest transaction state of any schema on database connection D 6233** is returned. Transaction states are (in order of lowest to highest): 6234** <ol> 6235** <li value="0"> SQLITE_TXN_NONE 6236** <li value="1"> SQLITE_TXN_READ 6237** <li value="2"> SQLITE_TXN_WRITE 6238** </ol> 6239** ^If the S argument to sqlite3_txn_state(D,S) is not the name of 6240** a valid schema, then -1 is returned. 6241*/ 6242int sqlite3_txn_state(sqlite3*,const char *zSchema); 6243 6244/* 6245** CAPI3REF: Allowed return values from [sqlite3_txn_state()] 6246** KEYWORDS: {transaction state} 6247** 6248** These constants define the current transaction state of a database file. 6249** ^The [sqlite3_txn_state(D,S)] interface returns one of these 6250** constants in order to describe the transaction state of schema S 6251** in [database connection] D. 6252** 6253** <dl> 6254** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt> 6255** <dd>The SQLITE_TXN_NONE state means that no transaction is currently 6256** pending.</dd> 6257** 6258** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt> 6259** <dd>The SQLITE_TXN_READ state means that the database is currently 6260** in a read transaction. Content has been read from the database file 6261** but nothing in the database file has changed. The transaction state 6262** will advanced to SQLITE_TXN_WRITE if any changes occur and there are 6263** no other conflicting concurrent write transactions. The transaction 6264** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or 6265** [COMMIT].</dd> 6266** 6267** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt> 6268** <dd>The SQLITE_TXN_WRITE state means that the database is currently 6269** in a write transaction. Content has been written to the database file 6270** but has not yet committed. The transaction state will change to 6271** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd> 6272*/ 6273#define SQLITE_TXN_NONE 0 6274#define SQLITE_TXN_READ 1 6275#define SQLITE_TXN_WRITE 2 6276 6277/* 6278** CAPI3REF: Find the next prepared statement 6279** METHOD: sqlite3 6280** 6281** ^This interface returns a pointer to the next [prepared statement] after 6282** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 6283** then this interface returns a pointer to the first prepared statement 6284** associated with the database connection pDb. ^If no prepared statement 6285** satisfies the conditions of this routine, it returns NULL. 6286** 6287** The [database connection] pointer D in a call to 6288** [sqlite3_next_stmt(D,S)] must refer to an open database 6289** connection and in particular must not be a NULL pointer. 6290*/ 6291sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 6292 6293/* 6294** CAPI3REF: Commit And Rollback Notification Callbacks 6295** METHOD: sqlite3 6296** 6297** ^The sqlite3_commit_hook() interface registers a callback 6298** function to be invoked whenever a transaction is [COMMIT | committed]. 6299** ^Any callback set by a previous call to sqlite3_commit_hook() 6300** for the same database connection is overridden. 6301** ^The sqlite3_rollback_hook() interface registers a callback 6302** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 6303** ^Any callback set by a previous call to sqlite3_rollback_hook() 6304** for the same database connection is overridden. 6305** ^The pArg argument is passed through to the callback. 6306** ^If the callback on a commit hook function returns non-zero, 6307** then the commit is converted into a rollback. 6308** 6309** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 6310** return the P argument from the previous call of the same function 6311** on the same [database connection] D, or NULL for 6312** the first call for each function on D. 6313** 6314** The commit and rollback hook callbacks are not reentrant. 6315** The callback implementation must not do anything that will modify 6316** the database connection that invoked the callback. Any actions 6317** to modify the database connection must be deferred until after the 6318** completion of the [sqlite3_step()] call that triggered the commit 6319** or rollback hook in the first place. 6320** Note that running any other SQL statements, including SELECT statements, 6321** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 6322** the database connections for the meaning of "modify" in this paragraph. 6323** 6324** ^Registering a NULL function disables the callback. 6325** 6326** ^When the commit hook callback routine returns zero, the [COMMIT] 6327** operation is allowed to continue normally. ^If the commit hook 6328** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 6329** ^The rollback hook is invoked on a rollback that results from a commit 6330** hook returning non-zero, just as it would be with any other rollback. 6331** 6332** ^For the purposes of this API, a transaction is said to have been 6333** rolled back if an explicit "ROLLBACK" statement is executed, or 6334** an error or constraint causes an implicit rollback to occur. 6335** ^The rollback callback is not invoked if a transaction is 6336** automatically rolled back because the database connection is closed. 6337** 6338** See also the [sqlite3_update_hook()] interface. 6339*/ 6340void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 6341void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 6342 6343/* 6344** CAPI3REF: Data Change Notification Callbacks 6345** METHOD: sqlite3 6346** 6347** ^The sqlite3_update_hook() interface registers a callback function 6348** with the [database connection] identified by the first argument 6349** to be invoked whenever a row is updated, inserted or deleted in 6350** a [rowid table]. 6351** ^Any callback set by a previous call to this function 6352** for the same database connection is overridden. 6353** 6354** ^The second argument is a pointer to the function to invoke when a 6355** row is updated, inserted or deleted in a rowid table. 6356** ^The first argument to the callback is a copy of the third argument 6357** to sqlite3_update_hook(). 6358** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 6359** or [SQLITE_UPDATE], depending on the operation that caused the callback 6360** to be invoked. 6361** ^The third and fourth arguments to the callback contain pointers to the 6362** database and table name containing the affected row. 6363** ^The final callback parameter is the [rowid] of the row. 6364** ^In the case of an update, this is the [rowid] after the update takes place. 6365** 6366** ^(The update hook is not invoked when internal system tables are 6367** modified (i.e. sqlite_sequence).)^ 6368** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 6369** 6370** ^In the current implementation, the update hook 6371** is not invoked when conflicting rows are deleted because of an 6372** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 6373** invoked when rows are deleted using the [truncate optimization]. 6374** The exceptions defined in this paragraph might change in a future 6375** release of SQLite. 6376** 6377** The update hook implementation must not do anything that will modify 6378** the database connection that invoked the update hook. Any actions 6379** to modify the database connection must be deferred until after the 6380** completion of the [sqlite3_step()] call that triggered the update hook. 6381** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 6382** database connections for the meaning of "modify" in this paragraph. 6383** 6384** ^The sqlite3_update_hook(D,C,P) function 6385** returns the P argument from the previous call 6386** on the same [database connection] D, or NULL for 6387** the first call on D. 6388** 6389** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 6390** and [sqlite3_preupdate_hook()] interfaces. 6391*/ 6392void *sqlite3_update_hook( 6393 sqlite3*, 6394 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 6395 void* 6396); 6397 6398/* 6399** CAPI3REF: Enable Or Disable Shared Pager Cache 6400** 6401** ^(This routine enables or disables the sharing of the database cache 6402** and schema data structures between [database connection | connections] 6403** to the same database. Sharing is enabled if the argument is true 6404** and disabled if the argument is false.)^ 6405** 6406** ^Cache sharing is enabled and disabled for an entire process. 6407** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 6408** In prior versions of SQLite, 6409** sharing was enabled or disabled for each thread separately. 6410** 6411** ^(The cache sharing mode set by this interface effects all subsequent 6412** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 6413** Existing database connections continue to use the sharing mode 6414** that was in effect at the time they were opened.)^ 6415** 6416** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 6417** successfully. An [error code] is returned otherwise.)^ 6418** 6419** ^Shared cache is disabled by default. It is recommended that it stay 6420** that way. In other words, do not use this routine. This interface 6421** continues to be provided for historical compatibility, but its use is 6422** discouraged. Any use of shared cache is discouraged. If shared cache 6423** must be used, it is recommended that shared cache only be enabled for 6424** individual database connections using the [sqlite3_open_v2()] interface 6425** with the [SQLITE_OPEN_SHAREDCACHE] flag. 6426** 6427** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 6428** and will always return SQLITE_MISUSE. On those systems, 6429** shared cache mode should be enabled per-database connection via 6430** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 6431** 6432** This interface is threadsafe on processors where writing a 6433** 32-bit integer is atomic. 6434** 6435** See Also: [SQLite Shared-Cache Mode] 6436*/ 6437int sqlite3_enable_shared_cache(int); 6438 6439/* 6440** CAPI3REF: Attempt To Free Heap Memory 6441** 6442** ^The sqlite3_release_memory() interface attempts to free N bytes 6443** of heap memory by deallocating non-essential memory allocations 6444** held by the database library. Memory used to cache database 6445** pages to improve performance is an example of non-essential memory. 6446** ^sqlite3_release_memory() returns the number of bytes actually freed, 6447** which might be more or less than the amount requested. 6448** ^The sqlite3_release_memory() routine is a no-op returning zero 6449** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 6450** 6451** See also: [sqlite3_db_release_memory()] 6452*/ 6453int sqlite3_release_memory(int); 6454 6455/* 6456** CAPI3REF: Free Memory Used By A Database Connection 6457** METHOD: sqlite3 6458** 6459** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 6460** memory as possible from database connection D. Unlike the 6461** [sqlite3_release_memory()] interface, this interface is in effect even 6462** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 6463** omitted. 6464** 6465** See also: [sqlite3_release_memory()] 6466*/ 6467int sqlite3_db_release_memory(sqlite3*); 6468 6469/* 6470** CAPI3REF: Impose A Limit On Heap Size 6471** 6472** These interfaces impose limits on the amount of heap memory that will be 6473** by all database connections within a single process. 6474** 6475** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 6476** soft limit on the amount of heap memory that may be allocated by SQLite. 6477** ^SQLite strives to keep heap memory utilization below the soft heap 6478** limit by reducing the number of pages held in the page cache 6479** as heap memory usages approaches the limit. 6480** ^The soft heap limit is "soft" because even though SQLite strives to stay 6481** below the limit, it will exceed the limit rather than generate 6482** an [SQLITE_NOMEM] error. In other words, the soft heap limit 6483** is advisory only. 6484** 6485** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of 6486** N bytes on the amount of memory that will be allocated. ^The 6487** sqlite3_hard_heap_limit64(N) interface is similar to 6488** sqlite3_soft_heap_limit64(N) except that memory allocations will fail 6489** when the hard heap limit is reached. 6490** 6491** ^The return value from both sqlite3_soft_heap_limit64() and 6492** sqlite3_hard_heap_limit64() is the size of 6493** the heap limit prior to the call, or negative in the case of an 6494** error. ^If the argument N is negative 6495** then no change is made to the heap limit. Hence, the current 6496** size of heap limits can be determined by invoking 6497** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1). 6498** 6499** ^Setting the heap limits to zero disables the heap limiter mechanism. 6500** 6501** ^The soft heap limit may not be greater than the hard heap limit. 6502** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N) 6503** is invoked with a value of N that is greater than the hard heap limit, 6504** the the soft heap limit is set to the value of the hard heap limit. 6505** ^The soft heap limit is automatically enabled whenever the hard heap 6506** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and 6507** the soft heap limit is outside the range of 1..N, then the soft heap 6508** limit is set to N. ^Invoking sqlite3_soft_heap_limit64(0) when the 6509** hard heap limit is enabled makes the soft heap limit equal to the 6510** hard heap limit. 6511** 6512** The memory allocation limits can also be adjusted using 6513** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit]. 6514** 6515** ^(The heap limits are not enforced in the current implementation 6516** if one or more of following conditions are true: 6517** 6518** <ul> 6519** <li> The limit value is set to zero. 6520** <li> Memory accounting is disabled using a combination of the 6521** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 6522** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 6523** <li> An alternative page cache implementation is specified using 6524** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 6525** <li> The page cache allocates from its own memory pool supplied 6526** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 6527** from the heap. 6528** </ul>)^ 6529** 6530** The circumstances under which SQLite will enforce the heap limits may 6531** changes in future releases of SQLite. 6532*/ 6533sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 6534sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N); 6535 6536/* 6537** CAPI3REF: Deprecated Soft Heap Limit Interface 6538** DEPRECATED 6539** 6540** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 6541** interface. This routine is provided for historical compatibility 6542** only. All new applications should use the 6543** [sqlite3_soft_heap_limit64()] interface rather than this one. 6544*/ 6545SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 6546 6547 6548/* 6549** CAPI3REF: Extract Metadata About A Column Of A Table 6550** METHOD: sqlite3 6551** 6552** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 6553** information about column C of table T in database D 6554** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 6555** interface returns SQLITE_OK and fills in the non-NULL pointers in 6556** the final five arguments with appropriate values if the specified 6557** column exists. ^The sqlite3_table_column_metadata() interface returns 6558** SQLITE_ERROR if the specified column does not exist. 6559** ^If the column-name parameter to sqlite3_table_column_metadata() is a 6560** NULL pointer, then this routine simply checks for the existence of the 6561** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 6562** does not. If the table name parameter T in a call to 6563** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 6564** undefined behavior. 6565** 6566** ^The column is identified by the second, third and fourth parameters to 6567** this function. ^(The second parameter is either the name of the database 6568** (i.e. "main", "temp", or an attached database) containing the specified 6569** table or NULL.)^ ^If it is NULL, then all attached databases are searched 6570** for the table using the same algorithm used by the database engine to 6571** resolve unqualified table references. 6572** 6573** ^The third and fourth parameters to this function are the table and column 6574** name of the desired column, respectively. 6575** 6576** ^Metadata is returned by writing to the memory locations passed as the 5th 6577** and subsequent parameters to this function. ^Any of these arguments may be 6578** NULL, in which case the corresponding element of metadata is omitted. 6579** 6580** ^(<blockquote> 6581** <table border="1"> 6582** <tr><th> Parameter <th> Output<br>Type <th> Description 6583** 6584** <tr><td> 5th <td> const char* <td> Data type 6585** <tr><td> 6th <td> const char* <td> Name of default collation sequence 6586** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 6587** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 6588** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 6589** </table> 6590** </blockquote>)^ 6591** 6592** ^The memory pointed to by the character pointers returned for the 6593** declaration type and collation sequence is valid until the next 6594** call to any SQLite API function. 6595** 6596** ^If the specified table is actually a view, an [error code] is returned. 6597** 6598** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 6599** is not a [WITHOUT ROWID] table and an 6600** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 6601** parameters are set for the explicitly declared column. ^(If there is no 6602** [INTEGER PRIMARY KEY] column, then the outputs 6603** for the [rowid] are set as follows: 6604** 6605** <pre> 6606** data type: "INTEGER" 6607** collation sequence: "BINARY" 6608** not null: 0 6609** primary key: 1 6610** auto increment: 0 6611** </pre>)^ 6612** 6613** ^This function causes all database schemas to be read from disk and 6614** parsed, if that has not already been done, and returns an error if 6615** any errors are encountered while loading the schema. 6616*/ 6617int sqlite3_table_column_metadata( 6618 sqlite3 *db, /* Connection handle */ 6619 const char *zDbName, /* Database name or NULL */ 6620 const char *zTableName, /* Table name */ 6621 const char *zColumnName, /* Column name */ 6622 char const **pzDataType, /* OUTPUT: Declared data type */ 6623 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 6624 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 6625 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 6626 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 6627); 6628 6629/* 6630** CAPI3REF: Load An Extension 6631** METHOD: sqlite3 6632** 6633** ^This interface loads an SQLite extension library from the named file. 6634** 6635** ^The sqlite3_load_extension() interface attempts to load an 6636** [SQLite extension] library contained in the file zFile. If 6637** the file cannot be loaded directly, attempts are made to load 6638** with various operating-system specific extensions added. 6639** So for example, if "samplelib" cannot be loaded, then names like 6640** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 6641** be tried also. 6642** 6643** ^The entry point is zProc. 6644** ^(zProc may be 0, in which case SQLite will try to come up with an 6645** entry point name on its own. It first tries "sqlite3_extension_init". 6646** If that does not work, it constructs a name "sqlite3_X_init" where the 6647** X is consists of the lower-case equivalent of all ASCII alphabetic 6648** characters in the filename from the last "/" to the first following 6649** "." and omitting any initial "lib".)^ 6650** ^The sqlite3_load_extension() interface returns 6651** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 6652** ^If an error occurs and pzErrMsg is not 0, then the 6653** [sqlite3_load_extension()] interface shall attempt to 6654** fill *pzErrMsg with error message text stored in memory 6655** obtained from [sqlite3_malloc()]. The calling function 6656** should free this memory by calling [sqlite3_free()]. 6657** 6658** ^Extension loading must be enabled using 6659** [sqlite3_enable_load_extension()] or 6660** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 6661** prior to calling this API, 6662** otherwise an error will be returned. 6663** 6664** <b>Security warning:</b> It is recommended that the 6665** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 6666** interface. The use of the [sqlite3_enable_load_extension()] interface 6667** should be avoided. This will keep the SQL function [load_extension()] 6668** disabled and prevent SQL injections from giving attackers 6669** access to extension loading capabilities. 6670** 6671** See also the [load_extension() SQL function]. 6672*/ 6673int sqlite3_load_extension( 6674 sqlite3 *db, /* Load the extension into this database connection */ 6675 const char *zFile, /* Name of the shared library containing extension */ 6676 const char *zProc, /* Entry point. Derived from zFile if 0 */ 6677 char **pzErrMsg /* Put error message here if not 0 */ 6678); 6679 6680/* 6681** CAPI3REF: Enable Or Disable Extension Loading 6682** METHOD: sqlite3 6683** 6684** ^So as not to open security holes in older applications that are 6685** unprepared to deal with [extension loading], and as a means of disabling 6686** [extension loading] while evaluating user-entered SQL, the following API 6687** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 6688** 6689** ^Extension loading is off by default. 6690** ^Call the sqlite3_enable_load_extension() routine with onoff==1 6691** to turn extension loading on and call it with onoff==0 to turn 6692** it back off again. 6693** 6694** ^This interface enables or disables both the C-API 6695** [sqlite3_load_extension()] and the SQL function [load_extension()]. 6696** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 6697** to enable or disable only the C-API.)^ 6698** 6699** <b>Security warning:</b> It is recommended that extension loading 6700** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 6701** rather than this interface, so the [load_extension()] SQL function 6702** remains disabled. This will prevent SQL injections from giving attackers 6703** access to extension loading capabilities. 6704*/ 6705int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6706 6707/* 6708** CAPI3REF: Automatically Load Statically Linked Extensions 6709** 6710** ^This interface causes the xEntryPoint() function to be invoked for 6711** each new [database connection] that is created. The idea here is that 6712** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6713** that is to be automatically loaded into all new database connections. 6714** 6715** ^(Even though the function prototype shows that xEntryPoint() takes 6716** no arguments and returns void, SQLite invokes xEntryPoint() with three 6717** arguments and expects an integer result as if the signature of the 6718** entry point where as follows: 6719** 6720** <blockquote><pre> 6721** int xEntryPoint( 6722** sqlite3 *db, 6723** const char **pzErrMsg, 6724** const struct sqlite3_api_routines *pThunk 6725** ); 6726** </pre></blockquote>)^ 6727** 6728** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6729** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6730** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6731** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6732** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6733** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6734** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6735** 6736** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6737** on the list of automatic extensions is a harmless no-op. ^No entry point 6738** will be called more than once for each database connection that is opened. 6739** 6740** See also: [sqlite3_reset_auto_extension()] 6741** and [sqlite3_cancel_auto_extension()] 6742*/ 6743int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6744 6745/* 6746** CAPI3REF: Cancel Automatic Extension Loading 6747** 6748** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6749** initialization routine X that was registered using a prior call to 6750** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6751** routine returns 1 if initialization routine X was successfully 6752** unregistered and it returns 0 if X was not on the list of initialization 6753** routines. 6754*/ 6755int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6756 6757/* 6758** CAPI3REF: Reset Automatic Extension Loading 6759** 6760** ^This interface disables all automatic extensions previously 6761** registered using [sqlite3_auto_extension()]. 6762*/ 6763void sqlite3_reset_auto_extension(void); 6764 6765/* 6766** The interface to the virtual-table mechanism is currently considered 6767** to be experimental. The interface might change in incompatible ways. 6768** If this is a problem for you, do not use the interface at this time. 6769** 6770** When the virtual-table mechanism stabilizes, we will declare the 6771** interface fixed, support it indefinitely, and remove this comment. 6772*/ 6773 6774/* 6775** Structures used by the virtual table interface 6776*/ 6777typedef struct sqlite3_vtab sqlite3_vtab; 6778typedef struct sqlite3_index_info sqlite3_index_info; 6779typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6780typedef struct sqlite3_module sqlite3_module; 6781 6782/* 6783** CAPI3REF: Virtual Table Object 6784** KEYWORDS: sqlite3_module {virtual table module} 6785** 6786** This structure, sometimes called a "virtual table module", 6787** defines the implementation of a [virtual table]. 6788** This structure consists mostly of methods for the module. 6789** 6790** ^A virtual table module is created by filling in a persistent 6791** instance of this structure and passing a pointer to that instance 6792** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6793** ^The registration remains valid until it is replaced by a different 6794** module or until the [database connection] closes. The content 6795** of this structure must not change while it is registered with 6796** any database connection. 6797*/ 6798struct sqlite3_module { 6799 int iVersion; 6800 int (*xCreate)(sqlite3*, void *pAux, 6801 int argc, const char *const*argv, 6802 sqlite3_vtab **ppVTab, char**); 6803 int (*xConnect)(sqlite3*, void *pAux, 6804 int argc, const char *const*argv, 6805 sqlite3_vtab **ppVTab, char**); 6806 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6807 int (*xDisconnect)(sqlite3_vtab *pVTab); 6808 int (*xDestroy)(sqlite3_vtab *pVTab); 6809 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6810 int (*xClose)(sqlite3_vtab_cursor*); 6811 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6812 int argc, sqlite3_value **argv); 6813 int (*xNext)(sqlite3_vtab_cursor*); 6814 int (*xEof)(sqlite3_vtab_cursor*); 6815 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6816 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6817 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6818 int (*xBegin)(sqlite3_vtab *pVTab); 6819 int (*xSync)(sqlite3_vtab *pVTab); 6820 int (*xCommit)(sqlite3_vtab *pVTab); 6821 int (*xRollback)(sqlite3_vtab *pVTab); 6822 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6823 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6824 void **ppArg); 6825 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6826 /* The methods above are in version 1 of the sqlite_module object. Those 6827 ** below are for version 2 and greater. */ 6828 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6829 int (*xRelease)(sqlite3_vtab *pVTab, int); 6830 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6831 /* The methods above are in versions 1 and 2 of the sqlite_module object. 6832 ** Those below are for version 3 and greater. */ 6833 int (*xShadowName)(const char*); 6834}; 6835 6836/* 6837** CAPI3REF: Virtual Table Indexing Information 6838** KEYWORDS: sqlite3_index_info 6839** 6840** The sqlite3_index_info structure and its substructures is used as part 6841** of the [virtual table] interface to 6842** pass information into and receive the reply from the [xBestIndex] 6843** method of a [virtual table module]. The fields under **Inputs** are the 6844** inputs to xBestIndex and are read-only. xBestIndex inserts its 6845** results into the **Outputs** fields. 6846** 6847** ^(The aConstraint[] array records WHERE clause constraints of the form: 6848** 6849** <blockquote>column OP expr</blockquote> 6850** 6851** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6852** stored in aConstraint[].op using one of the 6853** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6854** ^(The index of the column is stored in 6855** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6856** expr on the right-hand side can be evaluated (and thus the constraint 6857** is usable) and false if it cannot.)^ 6858** 6859** ^The optimizer automatically inverts terms of the form "expr OP column" 6860** and makes other simplifications to the WHERE clause in an attempt to 6861** get as many WHERE clause terms into the form shown above as possible. 6862** ^The aConstraint[] array only reports WHERE clause terms that are 6863** relevant to the particular virtual table being queried. 6864** 6865** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6866** ^Each term of aOrderBy records a column of the ORDER BY clause. 6867** 6868** The colUsed field indicates which columns of the virtual table may be 6869** required by the current scan. Virtual table columns are numbered from 6870** zero in the order in which they appear within the CREATE TABLE statement 6871** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6872** the corresponding bit is set within the colUsed mask if the column may be 6873** required by SQLite. If the table has at least 64 columns and any column 6874** to the right of the first 63 is required, then bit 63 of colUsed is also 6875** set. In other words, column iCol may be required if the expression 6876** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6877** non-zero. 6878** 6879** The [xBestIndex] method must fill aConstraintUsage[] with information 6880** about what parameters to pass to xFilter. ^If argvIndex>0 then 6881** the right-hand side of the corresponding aConstraint[] is evaluated 6882** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6883** is true, then the constraint is assumed to be fully handled by the 6884** virtual table and might not be checked again by the byte code.)^ ^(The 6885** aConstraintUsage[].omit flag is an optimization hint. When the omit flag 6886** is left in its default setting of false, the constraint will always be 6887** checked separately in byte code. If the omit flag is change to true, then 6888** the constraint may or may not be checked in byte code. In other words, 6889** when the omit flag is true there is no guarantee that the constraint will 6890** not be checked again using byte code.)^ 6891** 6892** ^The idxNum and idxPtr values are recorded and passed into the 6893** [xFilter] method. 6894** ^[sqlite3_free()] is used to free idxPtr if and only if 6895** needToFreeIdxPtr is true. 6896** 6897** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6898** the correct order to satisfy the ORDER BY clause so that no separate 6899** sorting step is required. 6900** 6901** ^The estimatedCost value is an estimate of the cost of a particular 6902** strategy. A cost of N indicates that the cost of the strategy is similar 6903** to a linear scan of an SQLite table with N rows. A cost of log(N) 6904** indicates that the expense of the operation is similar to that of a 6905** binary search on a unique indexed field of an SQLite table with N rows. 6906** 6907** ^The estimatedRows value is an estimate of the number of rows that 6908** will be returned by the strategy. 6909** 6910** The xBestIndex method may optionally populate the idxFlags field with a 6911** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6912** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6913** assumes that the strategy may visit at most one row. 6914** 6915** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6916** SQLite also assumes that if a call to the xUpdate() method is made as 6917** part of the same statement to delete or update a virtual table row and the 6918** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6919** any database changes. In other words, if the xUpdate() returns 6920** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6921** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6922** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6923** the xUpdate method are automatically rolled back by SQLite. 6924** 6925** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6926** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6927** If a virtual table extension is 6928** used with an SQLite version earlier than 3.8.2, the results of attempting 6929** to read or write the estimatedRows field are undefined (but are likely 6930** to include crashing the application). The estimatedRows field should 6931** therefore only be used if [sqlite3_libversion_number()] returns a 6932** value greater than or equal to 3008002. Similarly, the idxFlags field 6933** was added for [version 3.9.0] ([dateof:3.9.0]). 6934** It may therefore only be used if 6935** sqlite3_libversion_number() returns a value greater than or equal to 6936** 3009000. 6937*/ 6938struct sqlite3_index_info { 6939 /* Inputs */ 6940 int nConstraint; /* Number of entries in aConstraint */ 6941 struct sqlite3_index_constraint { 6942 int iColumn; /* Column constrained. -1 for ROWID */ 6943 unsigned char op; /* Constraint operator */ 6944 unsigned char usable; /* True if this constraint is usable */ 6945 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6946 } *aConstraint; /* Table of WHERE clause constraints */ 6947 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6948 struct sqlite3_index_orderby { 6949 int iColumn; /* Column number */ 6950 unsigned char desc; /* True for DESC. False for ASC. */ 6951 } *aOrderBy; /* The ORDER BY clause */ 6952 /* Outputs */ 6953 struct sqlite3_index_constraint_usage { 6954 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6955 unsigned char omit; /* Do not code a test for this constraint */ 6956 } *aConstraintUsage; 6957 int idxNum; /* Number used to identify the index */ 6958 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6959 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6960 int orderByConsumed; /* True if output is already ordered */ 6961 double estimatedCost; /* Estimated cost of using this index */ 6962 /* Fields below are only available in SQLite 3.8.2 and later */ 6963 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6964 /* Fields below are only available in SQLite 3.9.0 and later */ 6965 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6966 /* Fields below are only available in SQLite 3.10.0 and later */ 6967 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6968}; 6969 6970/* 6971** CAPI3REF: Virtual Table Scan Flags 6972** 6973** Virtual table implementations are allowed to set the 6974** [sqlite3_index_info].idxFlags field to some combination of 6975** these bits. 6976*/ 6977#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6978 6979/* 6980** CAPI3REF: Virtual Table Constraint Operator Codes 6981** 6982** These macros define the allowed values for the 6983** [sqlite3_index_info].aConstraint[].op field. Each value represents 6984** an operator that is part of a constraint term in the wHERE clause of 6985** a query that uses a [virtual table]. 6986*/ 6987#define SQLITE_INDEX_CONSTRAINT_EQ 2 6988#define SQLITE_INDEX_CONSTRAINT_GT 4 6989#define SQLITE_INDEX_CONSTRAINT_LE 8 6990#define SQLITE_INDEX_CONSTRAINT_LT 16 6991#define SQLITE_INDEX_CONSTRAINT_GE 32 6992#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6993#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6994#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6995#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6996#define SQLITE_INDEX_CONSTRAINT_NE 68 6997#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6998#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6999#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 7000#define SQLITE_INDEX_CONSTRAINT_IS 72 7001#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150 7002 7003/* 7004** CAPI3REF: Register A Virtual Table Implementation 7005** METHOD: sqlite3 7006** 7007** ^These routines are used to register a new [virtual table module] name. 7008** ^Module names must be registered before 7009** creating a new [virtual table] using the module and before using a 7010** preexisting [virtual table] for the module. 7011** 7012** ^The module name is registered on the [database connection] specified 7013** by the first parameter. ^The name of the module is given by the 7014** second parameter. ^The third parameter is a pointer to 7015** the implementation of the [virtual table module]. ^The fourth 7016** parameter is an arbitrary client data pointer that is passed through 7017** into the [xCreate] and [xConnect] methods of the virtual table module 7018** when a new virtual table is be being created or reinitialized. 7019** 7020** ^The sqlite3_create_module_v2() interface has a fifth parameter which 7021** is a pointer to a destructor for the pClientData. ^SQLite will 7022** invoke the destructor function (if it is not NULL) when SQLite 7023** no longer needs the pClientData pointer. ^The destructor will also 7024** be invoked if the call to sqlite3_create_module_v2() fails. 7025** ^The sqlite3_create_module() 7026** interface is equivalent to sqlite3_create_module_v2() with a NULL 7027** destructor. 7028** 7029** ^If the third parameter (the pointer to the sqlite3_module object) is 7030** NULL then no new module is create and any existing modules with the 7031** same name are dropped. 7032** 7033** See also: [sqlite3_drop_modules()] 7034*/ 7035int sqlite3_create_module( 7036 sqlite3 *db, /* SQLite connection to register module with */ 7037 const char *zName, /* Name of the module */ 7038 const sqlite3_module *p, /* Methods for the module */ 7039 void *pClientData /* Client data for xCreate/xConnect */ 7040); 7041int sqlite3_create_module_v2( 7042 sqlite3 *db, /* SQLite connection to register module with */ 7043 const char *zName, /* Name of the module */ 7044 const sqlite3_module *p, /* Methods for the module */ 7045 void *pClientData, /* Client data for xCreate/xConnect */ 7046 void(*xDestroy)(void*) /* Module destructor function */ 7047); 7048 7049/* 7050** CAPI3REF: Remove Unnecessary Virtual Table Implementations 7051** METHOD: sqlite3 7052** 7053** ^The sqlite3_drop_modules(D,L) interface removes all virtual 7054** table modules from database connection D except those named on list L. 7055** The L parameter must be either NULL or a pointer to an array of pointers 7056** to strings where the array is terminated by a single NULL pointer. 7057** ^If the L parameter is NULL, then all virtual table modules are removed. 7058** 7059** See also: [sqlite3_create_module()] 7060*/ 7061int sqlite3_drop_modules( 7062 sqlite3 *db, /* Remove modules from this connection */ 7063 const char **azKeep /* Except, do not remove the ones named here */ 7064); 7065 7066/* 7067** CAPI3REF: Virtual Table Instance Object 7068** KEYWORDS: sqlite3_vtab 7069** 7070** Every [virtual table module] implementation uses a subclass 7071** of this object to describe a particular instance 7072** of the [virtual table]. Each subclass will 7073** be tailored to the specific needs of the module implementation. 7074** The purpose of this superclass is to define certain fields that are 7075** common to all module implementations. 7076** 7077** ^Virtual tables methods can set an error message by assigning a 7078** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 7079** take care that any prior string is freed by a call to [sqlite3_free()] 7080** prior to assigning a new string to zErrMsg. ^After the error message 7081** is delivered up to the client application, the string will be automatically 7082** freed by sqlite3_free() and the zErrMsg field will be zeroed. 7083*/ 7084struct sqlite3_vtab { 7085 const sqlite3_module *pModule; /* The module for this virtual table */ 7086 int nRef; /* Number of open cursors */ 7087 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 7088 /* Virtual table implementations will typically add additional fields */ 7089}; 7090 7091/* 7092** CAPI3REF: Virtual Table Cursor Object 7093** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 7094** 7095** Every [virtual table module] implementation uses a subclass of the 7096** following structure to describe cursors that point into the 7097** [virtual table] and are used 7098** to loop through the virtual table. Cursors are created using the 7099** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 7100** by the [sqlite3_module.xClose | xClose] method. Cursors are used 7101** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 7102** of the module. Each module implementation will define 7103** the content of a cursor structure to suit its own needs. 7104** 7105** This superclass exists in order to define fields of the cursor that 7106** are common to all implementations. 7107*/ 7108struct sqlite3_vtab_cursor { 7109 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 7110 /* Virtual table implementations will typically add additional fields */ 7111}; 7112 7113/* 7114** CAPI3REF: Declare The Schema Of A Virtual Table 7115** 7116** ^The [xCreate] and [xConnect] methods of a 7117** [virtual table module] call this interface 7118** to declare the format (the names and datatypes of the columns) of 7119** the virtual tables they implement. 7120*/ 7121int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 7122 7123/* 7124** CAPI3REF: Overload A Function For A Virtual Table 7125** METHOD: sqlite3 7126** 7127** ^(Virtual tables can provide alternative implementations of functions 7128** using the [xFindFunction] method of the [virtual table module]. 7129** But global versions of those functions 7130** must exist in order to be overloaded.)^ 7131** 7132** ^(This API makes sure a global version of a function with a particular 7133** name and number of parameters exists. If no such function exists 7134** before this API is called, a new function is created.)^ ^The implementation 7135** of the new function always causes an exception to be thrown. So 7136** the new function is not good for anything by itself. Its only 7137** purpose is to be a placeholder function that can be overloaded 7138** by a [virtual table]. 7139*/ 7140int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 7141 7142/* 7143** The interface to the virtual-table mechanism defined above (back up 7144** to a comment remarkably similar to this one) is currently considered 7145** to be experimental. The interface might change in incompatible ways. 7146** If this is a problem for you, do not use the interface at this time. 7147** 7148** When the virtual-table mechanism stabilizes, we will declare the 7149** interface fixed, support it indefinitely, and remove this comment. 7150*/ 7151 7152/* 7153** CAPI3REF: A Handle To An Open BLOB 7154** KEYWORDS: {BLOB handle} {BLOB handles} 7155** 7156** An instance of this object represents an open BLOB on which 7157** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 7158** ^Objects of this type are created by [sqlite3_blob_open()] 7159** and destroyed by [sqlite3_blob_close()]. 7160** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 7161** can be used to read or write small subsections of the BLOB. 7162** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 7163*/ 7164typedef struct sqlite3_blob sqlite3_blob; 7165 7166/* 7167** CAPI3REF: Open A BLOB For Incremental I/O 7168** METHOD: sqlite3 7169** CONSTRUCTOR: sqlite3_blob 7170** 7171** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 7172** in row iRow, column zColumn, table zTable in database zDb; 7173** in other words, the same BLOB that would be selected by: 7174** 7175** <pre> 7176** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 7177** </pre>)^ 7178** 7179** ^(Parameter zDb is not the filename that contains the database, but 7180** rather the symbolic name of the database. For attached databases, this is 7181** the name that appears after the AS keyword in the [ATTACH] statement. 7182** For the main database file, the database name is "main". For TEMP 7183** tables, the database name is "temp".)^ 7184** 7185** ^If the flags parameter is non-zero, then the BLOB is opened for read 7186** and write access. ^If the flags parameter is zero, the BLOB is opened for 7187** read-only access. 7188** 7189** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 7190** in *ppBlob. Otherwise an [error code] is returned and, unless the error 7191** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 7192** the API is not misused, it is always safe to call [sqlite3_blob_close()] 7193** on *ppBlob after this function it returns. 7194** 7195** This function fails with SQLITE_ERROR if any of the following are true: 7196** <ul> 7197** <li> ^(Database zDb does not exist)^, 7198** <li> ^(Table zTable does not exist within database zDb)^, 7199** <li> ^(Table zTable is a WITHOUT ROWID table)^, 7200** <li> ^(Column zColumn does not exist)^, 7201** <li> ^(Row iRow is not present in the table)^, 7202** <li> ^(The specified column of row iRow contains a value that is not 7203** a TEXT or BLOB value)^, 7204** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 7205** constraint and the blob is being opened for read/write access)^, 7206** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 7207** column zColumn is part of a [child key] definition and the blob is 7208** being opened for read/write access)^. 7209** </ul> 7210** 7211** ^Unless it returns SQLITE_MISUSE, this function sets the 7212** [database connection] error code and message accessible via 7213** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7214** 7215** A BLOB referenced by sqlite3_blob_open() may be read using the 7216** [sqlite3_blob_read()] interface and modified by using 7217** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 7218** different row of the same table using the [sqlite3_blob_reopen()] 7219** interface. However, the column, table, or database of a [BLOB handle] 7220** cannot be changed after the [BLOB handle] is opened. 7221** 7222** ^(If the row that a BLOB handle points to is modified by an 7223** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 7224** then the BLOB handle is marked as "expired". 7225** This is true if any column of the row is changed, even a column 7226** other than the one the BLOB handle is open on.)^ 7227** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 7228** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 7229** ^(Changes written into a BLOB prior to the BLOB expiring are not 7230** rolled back by the expiration of the BLOB. Such changes will eventually 7231** commit if the transaction continues to completion.)^ 7232** 7233** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 7234** the opened blob. ^The size of a blob may not be changed by this 7235** interface. Use the [UPDATE] SQL command to change the size of a 7236** blob. 7237** 7238** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 7239** and the built-in [zeroblob] SQL function may be used to create a 7240** zero-filled blob to read or write using the incremental-blob interface. 7241** 7242** To avoid a resource leak, every open [BLOB handle] should eventually 7243** be released by a call to [sqlite3_blob_close()]. 7244** 7245** See also: [sqlite3_blob_close()], 7246** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 7247** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 7248*/ 7249int sqlite3_blob_open( 7250 sqlite3*, 7251 const char *zDb, 7252 const char *zTable, 7253 const char *zColumn, 7254 sqlite3_int64 iRow, 7255 int flags, 7256 sqlite3_blob **ppBlob 7257); 7258 7259/* 7260** CAPI3REF: Move a BLOB Handle to a New Row 7261** METHOD: sqlite3_blob 7262** 7263** ^This function is used to move an existing [BLOB handle] so that it points 7264** to a different row of the same database table. ^The new row is identified 7265** by the rowid value passed as the second argument. Only the row can be 7266** changed. ^The database, table and column on which the blob handle is open 7267** remain the same. Moving an existing [BLOB handle] to a new row is 7268** faster than closing the existing handle and opening a new one. 7269** 7270** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 7271** it must exist and there must be either a blob or text value stored in 7272** the nominated column.)^ ^If the new row is not present in the table, or if 7273** it does not contain a blob or text value, or if another error occurs, an 7274** SQLite error code is returned and the blob handle is considered aborted. 7275** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 7276** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 7277** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 7278** always returns zero. 7279** 7280** ^This function sets the database handle error code and message. 7281*/ 7282int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 7283 7284/* 7285** CAPI3REF: Close A BLOB Handle 7286** DESTRUCTOR: sqlite3_blob 7287** 7288** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 7289** unconditionally. Even if this routine returns an error code, the 7290** handle is still closed.)^ 7291** 7292** ^If the blob handle being closed was opened for read-write access, and if 7293** the database is in auto-commit mode and there are no other open read-write 7294** blob handles or active write statements, the current transaction is 7295** committed. ^If an error occurs while committing the transaction, an error 7296** code is returned and the transaction rolled back. 7297** 7298** Calling this function with an argument that is not a NULL pointer or an 7299** open blob handle results in undefined behaviour. ^Calling this routine 7300** with a null pointer (such as would be returned by a failed call to 7301** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 7302** is passed a valid open blob handle, the values returned by the 7303** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 7304*/ 7305int sqlite3_blob_close(sqlite3_blob *); 7306 7307/* 7308** CAPI3REF: Return The Size Of An Open BLOB 7309** METHOD: sqlite3_blob 7310** 7311** ^Returns the size in bytes of the BLOB accessible via the 7312** successfully opened [BLOB handle] in its only argument. ^The 7313** incremental blob I/O routines can only read or overwriting existing 7314** blob content; they cannot change the size of a blob. 7315** 7316** This routine only works on a [BLOB handle] which has been created 7317** by a prior successful call to [sqlite3_blob_open()] and which has not 7318** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7319** to this routine results in undefined and probably undesirable behavior. 7320*/ 7321int sqlite3_blob_bytes(sqlite3_blob *); 7322 7323/* 7324** CAPI3REF: Read Data From A BLOB Incrementally 7325** METHOD: sqlite3_blob 7326** 7327** ^(This function is used to read data from an open [BLOB handle] into a 7328** caller-supplied buffer. N bytes of data are copied into buffer Z 7329** from the open BLOB, starting at offset iOffset.)^ 7330** 7331** ^If offset iOffset is less than N bytes from the end of the BLOB, 7332** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 7333** less than zero, [SQLITE_ERROR] is returned and no data is read. 7334** ^The size of the blob (and hence the maximum value of N+iOffset) 7335** can be determined using the [sqlite3_blob_bytes()] interface. 7336** 7337** ^An attempt to read from an expired [BLOB handle] fails with an 7338** error code of [SQLITE_ABORT]. 7339** 7340** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 7341** Otherwise, an [error code] or an [extended error code] is returned.)^ 7342** 7343** This routine only works on a [BLOB handle] which has been created 7344** by a prior successful call to [sqlite3_blob_open()] and which has not 7345** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7346** to this routine results in undefined and probably undesirable behavior. 7347** 7348** See also: [sqlite3_blob_write()]. 7349*/ 7350int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 7351 7352/* 7353** CAPI3REF: Write Data Into A BLOB Incrementally 7354** METHOD: sqlite3_blob 7355** 7356** ^(This function is used to write data into an open [BLOB handle] from a 7357** caller-supplied buffer. N bytes of data are copied from the buffer Z 7358** into the open BLOB, starting at offset iOffset.)^ 7359** 7360** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 7361** Otherwise, an [error code] or an [extended error code] is returned.)^ 7362** ^Unless SQLITE_MISUSE is returned, this function sets the 7363** [database connection] error code and message accessible via 7364** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7365** 7366** ^If the [BLOB handle] passed as the first argument was not opened for 7367** writing (the flags parameter to [sqlite3_blob_open()] was zero), 7368** this function returns [SQLITE_READONLY]. 7369** 7370** This function may only modify the contents of the BLOB; it is 7371** not possible to increase the size of a BLOB using this API. 7372** ^If offset iOffset is less than N bytes from the end of the BLOB, 7373** [SQLITE_ERROR] is returned and no data is written. The size of the 7374** BLOB (and hence the maximum value of N+iOffset) can be determined 7375** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 7376** than zero [SQLITE_ERROR] is returned and no data is written. 7377** 7378** ^An attempt to write to an expired [BLOB handle] fails with an 7379** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 7380** before the [BLOB handle] expired are not rolled back by the 7381** expiration of the handle, though of course those changes might 7382** have been overwritten by the statement that expired the BLOB handle 7383** or by other independent statements. 7384** 7385** This routine only works on a [BLOB handle] which has been created 7386** by a prior successful call to [sqlite3_blob_open()] and which has not 7387** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7388** to this routine results in undefined and probably undesirable behavior. 7389** 7390** See also: [sqlite3_blob_read()]. 7391*/ 7392int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 7393 7394/* 7395** CAPI3REF: Virtual File System Objects 7396** 7397** A virtual filesystem (VFS) is an [sqlite3_vfs] object 7398** that SQLite uses to interact 7399** with the underlying operating system. Most SQLite builds come with a 7400** single default VFS that is appropriate for the host computer. 7401** New VFSes can be registered and existing VFSes can be unregistered. 7402** The following interfaces are provided. 7403** 7404** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 7405** ^Names are case sensitive. 7406** ^Names are zero-terminated UTF-8 strings. 7407** ^If there is no match, a NULL pointer is returned. 7408** ^If zVfsName is NULL then the default VFS is returned. 7409** 7410** ^New VFSes are registered with sqlite3_vfs_register(). 7411** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 7412** ^The same VFS can be registered multiple times without injury. 7413** ^To make an existing VFS into the default VFS, register it again 7414** with the makeDflt flag set. If two different VFSes with the 7415** same name are registered, the behavior is undefined. If a 7416** VFS is registered with a name that is NULL or an empty string, 7417** then the behavior is undefined. 7418** 7419** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 7420** ^(If the default VFS is unregistered, another VFS is chosen as 7421** the default. The choice for the new VFS is arbitrary.)^ 7422*/ 7423sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 7424int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 7425int sqlite3_vfs_unregister(sqlite3_vfs*); 7426 7427/* 7428** CAPI3REF: Mutexes 7429** 7430** The SQLite core uses these routines for thread 7431** synchronization. Though they are intended for internal 7432** use by SQLite, code that links against SQLite is 7433** permitted to use any of these routines. 7434** 7435** The SQLite source code contains multiple implementations 7436** of these mutex routines. An appropriate implementation 7437** is selected automatically at compile-time. The following 7438** implementations are available in the SQLite core: 7439** 7440** <ul> 7441** <li> SQLITE_MUTEX_PTHREADS 7442** <li> SQLITE_MUTEX_W32 7443** <li> SQLITE_MUTEX_NOOP 7444** </ul> 7445** 7446** The SQLITE_MUTEX_NOOP implementation is a set of routines 7447** that does no real locking and is appropriate for use in 7448** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 7449** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 7450** and Windows. 7451** 7452** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 7453** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 7454** implementation is included with the library. In this case the 7455** application must supply a custom mutex implementation using the 7456** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 7457** before calling sqlite3_initialize() or any other public sqlite3_ 7458** function that calls sqlite3_initialize(). 7459** 7460** ^The sqlite3_mutex_alloc() routine allocates a new 7461** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 7462** routine returns NULL if it is unable to allocate the requested 7463** mutex. The argument to sqlite3_mutex_alloc() must one of these 7464** integer constants: 7465** 7466** <ul> 7467** <li> SQLITE_MUTEX_FAST 7468** <li> SQLITE_MUTEX_RECURSIVE 7469** <li> SQLITE_MUTEX_STATIC_MAIN 7470** <li> SQLITE_MUTEX_STATIC_MEM 7471** <li> SQLITE_MUTEX_STATIC_OPEN 7472** <li> SQLITE_MUTEX_STATIC_PRNG 7473** <li> SQLITE_MUTEX_STATIC_LRU 7474** <li> SQLITE_MUTEX_STATIC_PMEM 7475** <li> SQLITE_MUTEX_STATIC_APP1 7476** <li> SQLITE_MUTEX_STATIC_APP2 7477** <li> SQLITE_MUTEX_STATIC_APP3 7478** <li> SQLITE_MUTEX_STATIC_VFS1 7479** <li> SQLITE_MUTEX_STATIC_VFS2 7480** <li> SQLITE_MUTEX_STATIC_VFS3 7481** </ul> 7482** 7483** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 7484** cause sqlite3_mutex_alloc() to create 7485** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 7486** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 7487** The mutex implementation does not need to make a distinction 7488** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 7489** not want to. SQLite will only request a recursive mutex in 7490** cases where it really needs one. If a faster non-recursive mutex 7491** implementation is available on the host platform, the mutex subsystem 7492** might return such a mutex in response to SQLITE_MUTEX_FAST. 7493** 7494** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 7495** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 7496** a pointer to a static preexisting mutex. ^Nine static mutexes are 7497** used by the current version of SQLite. Future versions of SQLite 7498** may add additional static mutexes. Static mutexes are for internal 7499** use by SQLite only. Applications that use SQLite mutexes should 7500** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 7501** SQLITE_MUTEX_RECURSIVE. 7502** 7503** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 7504** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 7505** returns a different mutex on every call. ^For the static 7506** mutex types, the same mutex is returned on every call that has 7507** the same type number. 7508** 7509** ^The sqlite3_mutex_free() routine deallocates a previously 7510** allocated dynamic mutex. Attempting to deallocate a static 7511** mutex results in undefined behavior. 7512** 7513** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 7514** to enter a mutex. ^If another thread is already within the mutex, 7515** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 7516** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 7517** upon successful entry. ^(Mutexes created using 7518** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 7519** In such cases, the 7520** mutex must be exited an equal number of times before another thread 7521** can enter.)^ If the same thread tries to enter any mutex other 7522** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 7523** 7524** ^(Some systems (for example, Windows 95) do not support the operation 7525** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 7526** will always return SQLITE_BUSY. The SQLite core only ever uses 7527** sqlite3_mutex_try() as an optimization so this is acceptable 7528** behavior.)^ 7529** 7530** ^The sqlite3_mutex_leave() routine exits a mutex that was 7531** previously entered by the same thread. The behavior 7532** is undefined if the mutex is not currently entered by the 7533** calling thread or is not currently allocated. 7534** 7535** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 7536** sqlite3_mutex_leave() is a NULL pointer, then all three routines 7537** behave as no-ops. 7538** 7539** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 7540*/ 7541sqlite3_mutex *sqlite3_mutex_alloc(int); 7542void sqlite3_mutex_free(sqlite3_mutex*); 7543void sqlite3_mutex_enter(sqlite3_mutex*); 7544int sqlite3_mutex_try(sqlite3_mutex*); 7545void sqlite3_mutex_leave(sqlite3_mutex*); 7546 7547/* 7548** CAPI3REF: Mutex Methods Object 7549** 7550** An instance of this structure defines the low-level routines 7551** used to allocate and use mutexes. 7552** 7553** Usually, the default mutex implementations provided by SQLite are 7554** sufficient, however the application has the option of substituting a custom 7555** implementation for specialized deployments or systems for which SQLite 7556** does not provide a suitable implementation. In this case, the application 7557** creates and populates an instance of this structure to pass 7558** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 7559** Additionally, an instance of this structure can be used as an 7560** output variable when querying the system for the current mutex 7561** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 7562** 7563** ^The xMutexInit method defined by this structure is invoked as 7564** part of system initialization by the sqlite3_initialize() function. 7565** ^The xMutexInit routine is called by SQLite exactly once for each 7566** effective call to [sqlite3_initialize()]. 7567** 7568** ^The xMutexEnd method defined by this structure is invoked as 7569** part of system shutdown by the sqlite3_shutdown() function. The 7570** implementation of this method is expected to release all outstanding 7571** resources obtained by the mutex methods implementation, especially 7572** those obtained by the xMutexInit method. ^The xMutexEnd() 7573** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 7574** 7575** ^(The remaining seven methods defined by this structure (xMutexAlloc, 7576** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 7577** xMutexNotheld) implement the following interfaces (respectively): 7578** 7579** <ul> 7580** <li> [sqlite3_mutex_alloc()] </li> 7581** <li> [sqlite3_mutex_free()] </li> 7582** <li> [sqlite3_mutex_enter()] </li> 7583** <li> [sqlite3_mutex_try()] </li> 7584** <li> [sqlite3_mutex_leave()] </li> 7585** <li> [sqlite3_mutex_held()] </li> 7586** <li> [sqlite3_mutex_notheld()] </li> 7587** </ul>)^ 7588** 7589** The only difference is that the public sqlite3_XXX functions enumerated 7590** above silently ignore any invocations that pass a NULL pointer instead 7591** of a valid mutex handle. The implementations of the methods defined 7592** by this structure are not required to handle this case. The results 7593** of passing a NULL pointer instead of a valid mutex handle are undefined 7594** (i.e. it is acceptable to provide an implementation that segfaults if 7595** it is passed a NULL pointer). 7596** 7597** The xMutexInit() method must be threadsafe. It must be harmless to 7598** invoke xMutexInit() multiple times within the same process and without 7599** intervening calls to xMutexEnd(). Second and subsequent calls to 7600** xMutexInit() must be no-ops. 7601** 7602** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 7603** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 7604** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 7605** memory allocation for a fast or recursive mutex. 7606** 7607** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 7608** called, but only if the prior call to xMutexInit returned SQLITE_OK. 7609** If xMutexInit fails in any way, it is expected to clean up after itself 7610** prior to returning. 7611*/ 7612typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 7613struct sqlite3_mutex_methods { 7614 int (*xMutexInit)(void); 7615 int (*xMutexEnd)(void); 7616 sqlite3_mutex *(*xMutexAlloc)(int); 7617 void (*xMutexFree)(sqlite3_mutex *); 7618 void (*xMutexEnter)(sqlite3_mutex *); 7619 int (*xMutexTry)(sqlite3_mutex *); 7620 void (*xMutexLeave)(sqlite3_mutex *); 7621 int (*xMutexHeld)(sqlite3_mutex *); 7622 int (*xMutexNotheld)(sqlite3_mutex *); 7623}; 7624 7625/* 7626** CAPI3REF: Mutex Verification Routines 7627** 7628** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 7629** are intended for use inside assert() statements. The SQLite core 7630** never uses these routines except inside an assert() and applications 7631** are advised to follow the lead of the core. The SQLite core only 7632** provides implementations for these routines when it is compiled 7633** with the SQLITE_DEBUG flag. External mutex implementations 7634** are only required to provide these routines if SQLITE_DEBUG is 7635** defined and if NDEBUG is not defined. 7636** 7637** These routines should return true if the mutex in their argument 7638** is held or not held, respectively, by the calling thread. 7639** 7640** The implementation is not required to provide versions of these 7641** routines that actually work. If the implementation does not provide working 7642** versions of these routines, it should at least provide stubs that always 7643** return true so that one does not get spurious assertion failures. 7644** 7645** If the argument to sqlite3_mutex_held() is a NULL pointer then 7646** the routine should return 1. This seems counter-intuitive since 7647** clearly the mutex cannot be held if it does not exist. But 7648** the reason the mutex does not exist is because the build is not 7649** using mutexes. And we do not want the assert() containing the 7650** call to sqlite3_mutex_held() to fail, so a non-zero return is 7651** the appropriate thing to do. The sqlite3_mutex_notheld() 7652** interface should also return 1 when given a NULL pointer. 7653*/ 7654#ifndef NDEBUG 7655int sqlite3_mutex_held(sqlite3_mutex*); 7656int sqlite3_mutex_notheld(sqlite3_mutex*); 7657#endif 7658 7659/* 7660** CAPI3REF: Mutex Types 7661** 7662** The [sqlite3_mutex_alloc()] interface takes a single argument 7663** which is one of these integer constants. 7664** 7665** The set of static mutexes may change from one SQLite release to the 7666** next. Applications that override the built-in mutex logic must be 7667** prepared to accommodate additional static mutexes. 7668*/ 7669#define SQLITE_MUTEX_FAST 0 7670#define SQLITE_MUTEX_RECURSIVE 1 7671#define SQLITE_MUTEX_STATIC_MAIN 2 7672#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 7673#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 7674#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 7675#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 7676#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 7677#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 7678#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 7679#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 7680#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 7681#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 7682#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 7683#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 7684#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 7685 7686/* Legacy compatibility: */ 7687#define SQLITE_MUTEX_STATIC_MASTER 2 7688 7689 7690/* 7691** CAPI3REF: Retrieve the mutex for a database connection 7692** METHOD: sqlite3 7693** 7694** ^This interface returns a pointer the [sqlite3_mutex] object that 7695** serializes access to the [database connection] given in the argument 7696** when the [threading mode] is Serialized. 7697** ^If the [threading mode] is Single-thread or Multi-thread then this 7698** routine returns a NULL pointer. 7699*/ 7700sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 7701 7702/* 7703** CAPI3REF: Low-Level Control Of Database Files 7704** METHOD: sqlite3 7705** KEYWORDS: {file control} 7706** 7707** ^The [sqlite3_file_control()] interface makes a direct call to the 7708** xFileControl method for the [sqlite3_io_methods] object associated 7709** with a particular database identified by the second argument. ^The 7710** name of the database is "main" for the main database or "temp" for the 7711** TEMP database, or the name that appears after the AS keyword for 7712** databases that are added using the [ATTACH] SQL command. 7713** ^A NULL pointer can be used in place of "main" to refer to the 7714** main database file. 7715** ^The third and fourth parameters to this routine 7716** are passed directly through to the second and third parameters of 7717** the xFileControl method. ^The return value of the xFileControl 7718** method becomes the return value of this routine. 7719** 7720** A few opcodes for [sqlite3_file_control()] are handled directly 7721** by the SQLite core and never invoke the 7722** sqlite3_io_methods.xFileControl method. 7723** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 7724** a pointer to the underlying [sqlite3_file] object to be written into 7725** the space pointed to by the 4th parameter. The 7726** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns 7727** the [sqlite3_file] object associated with the journal file instead of 7728** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns 7729** a pointer to the underlying [sqlite3_vfs] object for the file. 7730** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter 7731** from the pager. 7732** 7733** ^If the second parameter (zDbName) does not match the name of any 7734** open database file, then SQLITE_ERROR is returned. ^This error 7735** code is not remembered and will not be recalled by [sqlite3_errcode()] 7736** or [sqlite3_errmsg()]. The underlying xFileControl method might 7737** also return SQLITE_ERROR. There is no way to distinguish between 7738** an incorrect zDbName and an SQLITE_ERROR return from the underlying 7739** xFileControl method. 7740** 7741** See also: [file control opcodes] 7742*/ 7743int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 7744 7745/* 7746** CAPI3REF: Testing Interface 7747** 7748** ^The sqlite3_test_control() interface is used to read out internal 7749** state of SQLite and to inject faults into SQLite for testing 7750** purposes. ^The first parameter is an operation code that determines 7751** the number, meaning, and operation of all subsequent parameters. 7752** 7753** This interface is not for use by applications. It exists solely 7754** for verifying the correct operation of the SQLite library. Depending 7755** on how the SQLite library is compiled, this interface might not exist. 7756** 7757** The details of the operation codes, their meanings, the parameters 7758** they take, and what they do are all subject to change without notice. 7759** Unlike most of the SQLite API, this function is not guaranteed to 7760** operate consistently from one release to the next. 7761*/ 7762int sqlite3_test_control(int op, ...); 7763 7764/* 7765** CAPI3REF: Testing Interface Operation Codes 7766** 7767** These constants are the valid operation code parameters used 7768** as the first argument to [sqlite3_test_control()]. 7769** 7770** These parameters and their meanings are subject to change 7771** without notice. These values are for testing purposes only. 7772** Applications should not use any of these parameters or the 7773** [sqlite3_test_control()] interface. 7774*/ 7775#define SQLITE_TESTCTRL_FIRST 5 7776#define SQLITE_TESTCTRL_PRNG_SAVE 5 7777#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7778#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */ 7779#define SQLITE_TESTCTRL_BITVEC_TEST 8 7780#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7781#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7782#define SQLITE_TESTCTRL_PENDING_BYTE 11 7783#define SQLITE_TESTCTRL_ASSERT 12 7784#define SQLITE_TESTCTRL_ALWAYS 13 7785#define SQLITE_TESTCTRL_RESERVE 14 /* NOT USED */ 7786#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7787#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */ 7788#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7789#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17 7790#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7791#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7792#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7793#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7794#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7795#define SQLITE_TESTCTRL_BYTEORDER 22 7796#define SQLITE_TESTCTRL_ISINIT 23 7797#define SQLITE_TESTCTRL_SORTER_MMAP 24 7798#define SQLITE_TESTCTRL_IMPOSTER 25 7799#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7800#define SQLITE_TESTCTRL_RESULT_INTREAL 27 7801#define SQLITE_TESTCTRL_PRNG_SEED 28 7802#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29 7803#define SQLITE_TESTCTRL_SEEK_COUNT 30 7804#define SQLITE_TESTCTRL_TRACEFLAGS 31 7805#define SQLITE_TESTCTRL_LAST 31 /* Largest TESTCTRL */ 7806 7807/* 7808** CAPI3REF: SQL Keyword Checking 7809** 7810** These routines provide access to the set of SQL language keywords 7811** recognized by SQLite. Applications can uses these routines to determine 7812** whether or not a specific identifier needs to be escaped (for example, 7813** by enclosing in double-quotes) so as not to confuse the parser. 7814** 7815** The sqlite3_keyword_count() interface returns the number of distinct 7816** keywords understood by SQLite. 7817** 7818** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and 7819** makes *Z point to that keyword expressed as UTF8 and writes the number 7820** of bytes in the keyword into *L. The string that *Z points to is not 7821** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns 7822** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z 7823** or L are NULL or invalid pointers then calls to 7824** sqlite3_keyword_name(N,Z,L) result in undefined behavior. 7825** 7826** The sqlite3_keyword_check(Z,L) interface checks to see whether or not 7827** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero 7828** if it is and zero if not. 7829** 7830** The parser used by SQLite is forgiving. It is often possible to use 7831** a keyword as an identifier as long as such use does not result in a 7832** parsing ambiguity. For example, the statement 7833** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and 7834** creates a new table named "BEGIN" with three columns named 7835** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid 7836** using keywords as identifiers. Common techniques used to avoid keyword 7837** name collisions include: 7838** <ul> 7839** <li> Put all identifier names inside double-quotes. This is the official 7840** SQL way to escape identifier names. 7841** <li> Put identifier names inside [...]. This is not standard SQL, 7842** but it is what SQL Server does and so lots of programmers use this 7843** technique. 7844** <li> Begin every identifier with the letter "Z" as no SQL keywords start 7845** with "Z". 7846** <li> Include a digit somewhere in every identifier name. 7847** </ul> 7848** 7849** Note that the number of keywords understood by SQLite can depend on 7850** compile-time options. For example, "VACUUM" is not a keyword if 7851** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also, 7852** new keywords may be added to future releases of SQLite. 7853*/ 7854int sqlite3_keyword_count(void); 7855int sqlite3_keyword_name(int,const char**,int*); 7856int sqlite3_keyword_check(const char*,int); 7857 7858/* 7859** CAPI3REF: Dynamic String Object 7860** KEYWORDS: {dynamic string} 7861** 7862** An instance of the sqlite3_str object contains a dynamically-sized 7863** string under construction. 7864** 7865** The lifecycle of an sqlite3_str object is as follows: 7866** <ol> 7867** <li> ^The sqlite3_str object is created using [sqlite3_str_new()]. 7868** <li> ^Text is appended to the sqlite3_str object using various 7869** methods, such as [sqlite3_str_appendf()]. 7870** <li> ^The sqlite3_str object is destroyed and the string it created 7871** is returned using the [sqlite3_str_finish()] interface. 7872** </ol> 7873*/ 7874typedef struct sqlite3_str sqlite3_str; 7875 7876/* 7877** CAPI3REF: Create A New Dynamic String Object 7878** CONSTRUCTOR: sqlite3_str 7879** 7880** ^The [sqlite3_str_new(D)] interface allocates and initializes 7881** a new [sqlite3_str] object. To avoid memory leaks, the object returned by 7882** [sqlite3_str_new()] must be freed by a subsequent call to 7883** [sqlite3_str_finish(X)]. 7884** 7885** ^The [sqlite3_str_new(D)] interface always returns a pointer to a 7886** valid [sqlite3_str] object, though in the event of an out-of-memory 7887** error the returned object might be a special singleton that will 7888** silently reject new text, always return SQLITE_NOMEM from 7889** [sqlite3_str_errcode()], always return 0 for 7890** [sqlite3_str_length()], and always return NULL from 7891** [sqlite3_str_finish(X)]. It is always safe to use the value 7892** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter 7893** to any of the other [sqlite3_str] methods. 7894** 7895** The D parameter to [sqlite3_str_new(D)] may be NULL. If the 7896** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum 7897** length of the string contained in the [sqlite3_str] object will be 7898** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead 7899** of [SQLITE_MAX_LENGTH]. 7900*/ 7901sqlite3_str *sqlite3_str_new(sqlite3*); 7902 7903/* 7904** CAPI3REF: Finalize A Dynamic String 7905** DESTRUCTOR: sqlite3_str 7906** 7907** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X 7908** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()] 7909** that contains the constructed string. The calling application should 7910** pass the returned value to [sqlite3_free()] to avoid a memory leak. 7911** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any 7912** errors were encountered during construction of the string. ^The 7913** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the 7914** string in [sqlite3_str] object X is zero bytes long. 7915*/ 7916char *sqlite3_str_finish(sqlite3_str*); 7917 7918/* 7919** CAPI3REF: Add Content To A Dynamic String 7920** METHOD: sqlite3_str 7921** 7922** These interfaces add content to an sqlite3_str object previously obtained 7923** from [sqlite3_str_new()]. 7924** 7925** ^The [sqlite3_str_appendf(X,F,...)] and 7926** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf] 7927** functionality of SQLite to append formatted text onto the end of 7928** [sqlite3_str] object X. 7929** 7930** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S 7931** onto the end of the [sqlite3_str] object X. N must be non-negative. 7932** S must contain at least N non-zero bytes of content. To append a 7933** zero-terminated string in its entirety, use the [sqlite3_str_appendall()] 7934** method instead. 7935** 7936** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of 7937** zero-terminated string S onto the end of [sqlite3_str] object X. 7938** 7939** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the 7940** single-byte character C onto the end of [sqlite3_str] object X. 7941** ^This method can be used, for example, to add whitespace indentation. 7942** 7943** ^The [sqlite3_str_reset(X)] method resets the string under construction 7944** inside [sqlite3_str] object X back to zero bytes in length. 7945** 7946** These methods do not return a result code. ^If an error occurs, that fact 7947** is recorded in the [sqlite3_str] object and can be recovered by a 7948** subsequent call to [sqlite3_str_errcode(X)]. 7949*/ 7950void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...); 7951void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list); 7952void sqlite3_str_append(sqlite3_str*, const char *zIn, int N); 7953void sqlite3_str_appendall(sqlite3_str*, const char *zIn); 7954void sqlite3_str_appendchar(sqlite3_str*, int N, char C); 7955void sqlite3_str_reset(sqlite3_str*); 7956 7957/* 7958** CAPI3REF: Status Of A Dynamic String 7959** METHOD: sqlite3_str 7960** 7961** These interfaces return the current status of an [sqlite3_str] object. 7962** 7963** ^If any prior errors have occurred while constructing the dynamic string 7964** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return 7965** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns 7966** [SQLITE_NOMEM] following any out-of-memory error, or 7967** [SQLITE_TOOBIG] if the size of the dynamic string exceeds 7968** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors. 7969** 7970** ^The [sqlite3_str_length(X)] method returns the current length, in bytes, 7971** of the dynamic string under construction in [sqlite3_str] object X. 7972** ^The length returned by [sqlite3_str_length(X)] does not include the 7973** zero-termination byte. 7974** 7975** ^The [sqlite3_str_value(X)] method returns a pointer to the current 7976** content of the dynamic string under construction in X. The value 7977** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X 7978** and might be freed or altered by any subsequent method on the same 7979** [sqlite3_str] object. Applications must not used the pointer returned 7980** [sqlite3_str_value(X)] after any subsequent method call on the same 7981** object. ^Applications may change the content of the string returned 7982** by [sqlite3_str_value(X)] as long as they do not write into any bytes 7983** outside the range of 0 to [sqlite3_str_length(X)] and do not read or 7984** write any byte after any subsequent sqlite3_str method call. 7985*/ 7986int sqlite3_str_errcode(sqlite3_str*); 7987int sqlite3_str_length(sqlite3_str*); 7988char *sqlite3_str_value(sqlite3_str*); 7989 7990/* 7991** CAPI3REF: SQLite Runtime Status 7992** 7993** ^These interfaces are used to retrieve runtime status information 7994** about the performance of SQLite, and optionally to reset various 7995** highwater marks. ^The first argument is an integer code for 7996** the specific parameter to measure. ^(Recognized integer codes 7997** are of the form [status parameters | SQLITE_STATUS_...].)^ 7998** ^The current value of the parameter is returned into *pCurrent. 7999** ^The highest recorded value is returned in *pHighwater. ^If the 8000** resetFlag is true, then the highest record value is reset after 8001** *pHighwater is written. ^(Some parameters do not record the highest 8002** value. For those parameters 8003** nothing is written into *pHighwater and the resetFlag is ignored.)^ 8004** ^(Other parameters record only the highwater mark and not the current 8005** value. For these latter parameters nothing is written into *pCurrent.)^ 8006** 8007** ^The sqlite3_status() and sqlite3_status64() routines return 8008** SQLITE_OK on success and a non-zero [error code] on failure. 8009** 8010** If either the current value or the highwater mark is too large to 8011** be represented by a 32-bit integer, then the values returned by 8012** sqlite3_status() are undefined. 8013** 8014** See also: [sqlite3_db_status()] 8015*/ 8016int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 8017int sqlite3_status64( 8018 int op, 8019 sqlite3_int64 *pCurrent, 8020 sqlite3_int64 *pHighwater, 8021 int resetFlag 8022); 8023 8024 8025/* 8026** CAPI3REF: Status Parameters 8027** KEYWORDS: {status parameters} 8028** 8029** These integer constants designate various run-time status parameters 8030** that can be returned by [sqlite3_status()]. 8031** 8032** <dl> 8033** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 8034** <dd>This parameter is the current amount of memory checked out 8035** using [sqlite3_malloc()], either directly or indirectly. The 8036** figure includes calls made to [sqlite3_malloc()] by the application 8037** and internal memory usage by the SQLite library. Auxiliary page-cache 8038** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 8039** this parameter. The amount returned is the sum of the allocation 8040** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 8041** 8042** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 8043** <dd>This parameter records the largest memory allocation request 8044** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 8045** internal equivalents). Only the value returned in the 8046** *pHighwater parameter to [sqlite3_status()] is of interest. 8047** The value written into the *pCurrent parameter is undefined.</dd>)^ 8048** 8049** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 8050** <dd>This parameter records the number of separate memory allocations 8051** currently checked out.</dd>)^ 8052** 8053** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 8054** <dd>This parameter returns the number of pages used out of the 8055** [pagecache memory allocator] that was configured using 8056** [SQLITE_CONFIG_PAGECACHE]. The 8057** value returned is in pages, not in bytes.</dd>)^ 8058** 8059** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 8060** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 8061** <dd>This parameter returns the number of bytes of page cache 8062** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 8063** buffer and where forced to overflow to [sqlite3_malloc()]. The 8064** returned value includes allocations that overflowed because they 8065** where too large (they were larger than the "sz" parameter to 8066** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 8067** no space was left in the page cache.</dd>)^ 8068** 8069** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 8070** <dd>This parameter records the largest memory allocation request 8071** handed to the [pagecache memory allocator]. Only the value returned in the 8072** *pHighwater parameter to [sqlite3_status()] is of interest. 8073** The value written into the *pCurrent parameter is undefined.</dd>)^ 8074** 8075** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 8076** <dd>No longer used.</dd> 8077** 8078** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 8079** <dd>No longer used.</dd> 8080** 8081** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 8082** <dd>No longer used.</dd> 8083** 8084** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 8085** <dd>The *pHighwater parameter records the deepest parser stack. 8086** The *pCurrent value is undefined. The *pHighwater value is only 8087** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 8088** </dl> 8089** 8090** New status parameters may be added from time to time. 8091*/ 8092#define SQLITE_STATUS_MEMORY_USED 0 8093#define SQLITE_STATUS_PAGECACHE_USED 1 8094#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 8095#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 8096#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 8097#define SQLITE_STATUS_MALLOC_SIZE 5 8098#define SQLITE_STATUS_PARSER_STACK 6 8099#define SQLITE_STATUS_PAGECACHE_SIZE 7 8100#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 8101#define SQLITE_STATUS_MALLOC_COUNT 9 8102 8103/* 8104** CAPI3REF: Database Connection Status 8105** METHOD: sqlite3 8106** 8107** ^This interface is used to retrieve runtime status information 8108** about a single [database connection]. ^The first argument is the 8109** database connection object to be interrogated. ^The second argument 8110** is an integer constant, taken from the set of 8111** [SQLITE_DBSTATUS options], that 8112** determines the parameter to interrogate. The set of 8113** [SQLITE_DBSTATUS options] is likely 8114** to grow in future releases of SQLite. 8115** 8116** ^The current value of the requested parameter is written into *pCur 8117** and the highest instantaneous value is written into *pHiwtr. ^If 8118** the resetFlg is true, then the highest instantaneous value is 8119** reset back down to the current value. 8120** 8121** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 8122** non-zero [error code] on failure. 8123** 8124** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 8125*/ 8126int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 8127 8128/* 8129** CAPI3REF: Status Parameters for database connections 8130** KEYWORDS: {SQLITE_DBSTATUS options} 8131** 8132** These constants are the available integer "verbs" that can be passed as 8133** the second argument to the [sqlite3_db_status()] interface. 8134** 8135** New verbs may be added in future releases of SQLite. Existing verbs 8136** might be discontinued. Applications should check the return code from 8137** [sqlite3_db_status()] to make sure that the call worked. 8138** The [sqlite3_db_status()] interface will return a non-zero error code 8139** if a discontinued or unsupported verb is invoked. 8140** 8141** <dl> 8142** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 8143** <dd>This parameter returns the number of lookaside memory slots currently 8144** checked out.</dd>)^ 8145** 8146** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 8147** <dd>This parameter returns the number of malloc attempts that were 8148** satisfied using lookaside memory. Only the high-water value is meaningful; 8149** the current value is always zero.)^ 8150** 8151** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 8152** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 8153** <dd>This parameter returns the number malloc attempts that might have 8154** been satisfied using lookaside memory but failed due to the amount of 8155** memory requested being larger than the lookaside slot size. 8156** Only the high-water value is meaningful; 8157** the current value is always zero.)^ 8158** 8159** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 8160** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 8161** <dd>This parameter returns the number malloc attempts that might have 8162** been satisfied using lookaside memory but failed due to all lookaside 8163** memory already being in use. 8164** Only the high-water value is meaningful; 8165** the current value is always zero.)^ 8166** 8167** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 8168** <dd>This parameter returns the approximate number of bytes of heap 8169** memory used by all pager caches associated with the database connection.)^ 8170** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 8171** 8172** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 8173** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 8174** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 8175** pager cache is shared between two or more connections the bytes of heap 8176** memory used by that pager cache is divided evenly between the attached 8177** connections.)^ In other words, if none of the pager caches associated 8178** with the database connection are shared, this request returns the same 8179** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 8180** shared, the value returned by this call will be smaller than that returned 8181** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 8182** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 8183** 8184** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 8185** <dd>This parameter returns the approximate number of bytes of heap 8186** memory used to store the schema for all databases associated 8187** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 8188** ^The full amount of memory used by the schemas is reported, even if the 8189** schema memory is shared with other database connections due to 8190** [shared cache mode] being enabled. 8191** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 8192** 8193** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 8194** <dd>This parameter returns the approximate number of bytes of heap 8195** and lookaside memory used by all prepared statements associated with 8196** the database connection.)^ 8197** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 8198** </dd> 8199** 8200** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 8201** <dd>This parameter returns the number of pager cache hits that have 8202** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 8203** is always 0. 8204** </dd> 8205** 8206** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 8207** <dd>This parameter returns the number of pager cache misses that have 8208** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 8209** is always 0. 8210** </dd> 8211** 8212** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 8213** <dd>This parameter returns the number of dirty cache entries that have 8214** been written to disk. Specifically, the number of pages written to the 8215** wal file in wal mode databases, or the number of pages written to the 8216** database file in rollback mode databases. Any pages written as part of 8217** transaction rollback or database recovery operations are not included. 8218** If an IO or other error occurs while writing a page to disk, the effect 8219** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 8220** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 8221** </dd> 8222** 8223** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 8224** <dd>This parameter returns the number of dirty cache entries that have 8225** been written to disk in the middle of a transaction due to the page 8226** cache overflowing. Transactions are more efficient if they are written 8227** to disk all at once. When pages spill mid-transaction, that introduces 8228** additional overhead. This parameter can be used help identify 8229** inefficiencies that can be resolved by increasing the cache size. 8230** </dd> 8231** 8232** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 8233** <dd>This parameter returns zero for the current value if and only if 8234** all foreign key constraints (deferred or immediate) have been 8235** resolved.)^ ^The highwater mark is always 0. 8236** </dd> 8237** </dl> 8238*/ 8239#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 8240#define SQLITE_DBSTATUS_CACHE_USED 1 8241#define SQLITE_DBSTATUS_SCHEMA_USED 2 8242#define SQLITE_DBSTATUS_STMT_USED 3 8243#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 8244#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 8245#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 8246#define SQLITE_DBSTATUS_CACHE_HIT 7 8247#define SQLITE_DBSTATUS_CACHE_MISS 8 8248#define SQLITE_DBSTATUS_CACHE_WRITE 9 8249#define SQLITE_DBSTATUS_DEFERRED_FKS 10 8250#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 8251#define SQLITE_DBSTATUS_CACHE_SPILL 12 8252#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 8253 8254 8255/* 8256** CAPI3REF: Prepared Statement Status 8257** METHOD: sqlite3_stmt 8258** 8259** ^(Each prepared statement maintains various 8260** [SQLITE_STMTSTATUS counters] that measure the number 8261** of times it has performed specific operations.)^ These counters can 8262** be used to monitor the performance characteristics of the prepared 8263** statements. For example, if the number of table steps greatly exceeds 8264** the number of table searches or result rows, that would tend to indicate 8265** that the prepared statement is using a full table scan rather than 8266** an index. 8267** 8268** ^(This interface is used to retrieve and reset counter values from 8269** a [prepared statement]. The first argument is the prepared statement 8270** object to be interrogated. The second argument 8271** is an integer code for a specific [SQLITE_STMTSTATUS counter] 8272** to be interrogated.)^ 8273** ^The current value of the requested counter is returned. 8274** ^If the resetFlg is true, then the counter is reset to zero after this 8275** interface call returns. 8276** 8277** See also: [sqlite3_status()] and [sqlite3_db_status()]. 8278*/ 8279int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 8280 8281/* 8282** CAPI3REF: Status Parameters for prepared statements 8283** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 8284** 8285** These preprocessor macros define integer codes that name counter 8286** values associated with the [sqlite3_stmt_status()] interface. 8287** The meanings of the various counters are as follows: 8288** 8289** <dl> 8290** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 8291** <dd>^This is the number of times that SQLite has stepped forward in 8292** a table as part of a full table scan. Large numbers for this counter 8293** may indicate opportunities for performance improvement through 8294** careful use of indices.</dd> 8295** 8296** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 8297** <dd>^This is the number of sort operations that have occurred. 8298** A non-zero value in this counter may indicate an opportunity to 8299** improvement performance through careful use of indices.</dd> 8300** 8301** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 8302** <dd>^This is the number of rows inserted into transient indices that 8303** were created automatically in order to help joins run faster. 8304** A non-zero value in this counter may indicate an opportunity to 8305** improvement performance by adding permanent indices that do not 8306** need to be reinitialized each time the statement is run.</dd> 8307** 8308** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 8309** <dd>^This is the number of virtual machine operations executed 8310** by the prepared statement if that number is less than or equal 8311** to 2147483647. The number of virtual machine operations can be 8312** used as a proxy for the total work done by the prepared statement. 8313** If the number of virtual machine operations exceeds 2147483647 8314** then the value returned by this statement status code is undefined. 8315** 8316** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 8317** <dd>^This is the number of times that the prepare statement has been 8318** automatically regenerated due to schema changes or changes to 8319** [bound parameters] that might affect the query plan. 8320** 8321** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 8322** <dd>^This is the number of times that the prepared statement has 8323** been run. A single "run" for the purposes of this counter is one 8324** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 8325** The counter is incremented on the first [sqlite3_step()] call of each 8326** cycle. 8327** 8328** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 8329** <dd>^This is the approximate number of bytes of heap memory 8330** used to store the prepared statement. ^This value is not actually 8331** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 8332** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 8333** </dd> 8334** </dl> 8335*/ 8336#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 8337#define SQLITE_STMTSTATUS_SORT 2 8338#define SQLITE_STMTSTATUS_AUTOINDEX 3 8339#define SQLITE_STMTSTATUS_VM_STEP 4 8340#define SQLITE_STMTSTATUS_REPREPARE 5 8341#define SQLITE_STMTSTATUS_RUN 6 8342#define SQLITE_STMTSTATUS_MEMUSED 99 8343 8344/* 8345** CAPI3REF: Custom Page Cache Object 8346** 8347** The sqlite3_pcache type is opaque. It is implemented by 8348** the pluggable module. The SQLite core has no knowledge of 8349** its size or internal structure and never deals with the 8350** sqlite3_pcache object except by holding and passing pointers 8351** to the object. 8352** 8353** See [sqlite3_pcache_methods2] for additional information. 8354*/ 8355typedef struct sqlite3_pcache sqlite3_pcache; 8356 8357/* 8358** CAPI3REF: Custom Page Cache Object 8359** 8360** The sqlite3_pcache_page object represents a single page in the 8361** page cache. The page cache will allocate instances of this 8362** object. Various methods of the page cache use pointers to instances 8363** of this object as parameters or as their return value. 8364** 8365** See [sqlite3_pcache_methods2] for additional information. 8366*/ 8367typedef struct sqlite3_pcache_page sqlite3_pcache_page; 8368struct sqlite3_pcache_page { 8369 void *pBuf; /* The content of the page */ 8370 void *pExtra; /* Extra information associated with the page */ 8371}; 8372 8373/* 8374** CAPI3REF: Application Defined Page Cache. 8375** KEYWORDS: {page cache} 8376** 8377** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 8378** register an alternative page cache implementation by passing in an 8379** instance of the sqlite3_pcache_methods2 structure.)^ 8380** In many applications, most of the heap memory allocated by 8381** SQLite is used for the page cache. 8382** By implementing a 8383** custom page cache using this API, an application can better control 8384** the amount of memory consumed by SQLite, the way in which 8385** that memory is allocated and released, and the policies used to 8386** determine exactly which parts of a database file are cached and for 8387** how long. 8388** 8389** The alternative page cache mechanism is an 8390** extreme measure that is only needed by the most demanding applications. 8391** The built-in page cache is recommended for most uses. 8392** 8393** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 8394** internal buffer by SQLite within the call to [sqlite3_config]. Hence 8395** the application may discard the parameter after the call to 8396** [sqlite3_config()] returns.)^ 8397** 8398** [[the xInit() page cache method]] 8399** ^(The xInit() method is called once for each effective 8400** call to [sqlite3_initialize()])^ 8401** (usually only once during the lifetime of the process). ^(The xInit() 8402** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 8403** The intent of the xInit() method is to set up global data structures 8404** required by the custom page cache implementation. 8405** ^(If the xInit() method is NULL, then the 8406** built-in default page cache is used instead of the application defined 8407** page cache.)^ 8408** 8409** [[the xShutdown() page cache method]] 8410** ^The xShutdown() method is called by [sqlite3_shutdown()]. 8411** It can be used to clean up 8412** any outstanding resources before process shutdown, if required. 8413** ^The xShutdown() method may be NULL. 8414** 8415** ^SQLite automatically serializes calls to the xInit method, 8416** so the xInit method need not be threadsafe. ^The 8417** xShutdown method is only called from [sqlite3_shutdown()] so it does 8418** not need to be threadsafe either. All other methods must be threadsafe 8419** in multithreaded applications. 8420** 8421** ^SQLite will never invoke xInit() more than once without an intervening 8422** call to xShutdown(). 8423** 8424** [[the xCreate() page cache methods]] 8425** ^SQLite invokes the xCreate() method to construct a new cache instance. 8426** SQLite will typically create one cache instance for each open database file, 8427** though this is not guaranteed. ^The 8428** first parameter, szPage, is the size in bytes of the pages that must 8429** be allocated by the cache. ^szPage will always a power of two. ^The 8430** second parameter szExtra is a number of bytes of extra storage 8431** associated with each page cache entry. ^The szExtra parameter will 8432** a number less than 250. SQLite will use the 8433** extra szExtra bytes on each page to store metadata about the underlying 8434** database page on disk. The value passed into szExtra depends 8435** on the SQLite version, the target platform, and how SQLite was compiled. 8436** ^The third argument to xCreate(), bPurgeable, is true if the cache being 8437** created will be used to cache database pages of a file stored on disk, or 8438** false if it is used for an in-memory database. The cache implementation 8439** does not have to do anything special based with the value of bPurgeable; 8440** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 8441** never invoke xUnpin() except to deliberately delete a page. 8442** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 8443** false will always have the "discard" flag set to true. 8444** ^Hence, a cache created with bPurgeable false will 8445** never contain any unpinned pages. 8446** 8447** [[the xCachesize() page cache method]] 8448** ^(The xCachesize() method may be called at any time by SQLite to set the 8449** suggested maximum cache-size (number of pages stored by) the cache 8450** instance passed as the first argument. This is the value configured using 8451** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 8452** parameter, the implementation is not required to do anything with this 8453** value; it is advisory only. 8454** 8455** [[the xPagecount() page cache methods]] 8456** The xPagecount() method must return the number of pages currently 8457** stored in the cache, both pinned and unpinned. 8458** 8459** [[the xFetch() page cache methods]] 8460** The xFetch() method locates a page in the cache and returns a pointer to 8461** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 8462** The pBuf element of the returned sqlite3_pcache_page object will be a 8463** pointer to a buffer of szPage bytes used to store the content of a 8464** single database page. The pExtra element of sqlite3_pcache_page will be 8465** a pointer to the szExtra bytes of extra storage that SQLite has requested 8466** for each entry in the page cache. 8467** 8468** The page to be fetched is determined by the key. ^The minimum key value 8469** is 1. After it has been retrieved using xFetch, the page is considered 8470** to be "pinned". 8471** 8472** If the requested page is already in the page cache, then the page cache 8473** implementation must return a pointer to the page buffer with its content 8474** intact. If the requested page is not already in the cache, then the 8475** cache implementation should use the value of the createFlag 8476** parameter to help it determined what action to take: 8477** 8478** <table border=1 width=85% align=center> 8479** <tr><th> createFlag <th> Behavior when page is not already in cache 8480** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 8481** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 8482** Otherwise return NULL. 8483** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 8484** NULL if allocating a new page is effectively impossible. 8485** </table> 8486** 8487** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 8488** will only use a createFlag of 2 after a prior call with a createFlag of 1 8489** failed.)^ In between the xFetch() calls, SQLite may 8490** attempt to unpin one or more cache pages by spilling the content of 8491** pinned pages to disk and synching the operating system disk cache. 8492** 8493** [[the xUnpin() page cache method]] 8494** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 8495** as its second argument. If the third parameter, discard, is non-zero, 8496** then the page must be evicted from the cache. 8497** ^If the discard parameter is 8498** zero, then the page may be discarded or retained at the discretion of 8499** page cache implementation. ^The page cache implementation 8500** may choose to evict unpinned pages at any time. 8501** 8502** The cache must not perform any reference counting. A single 8503** call to xUnpin() unpins the page regardless of the number of prior calls 8504** to xFetch(). 8505** 8506** [[the xRekey() page cache methods]] 8507** The xRekey() method is used to change the key value associated with the 8508** page passed as the second argument. If the cache 8509** previously contains an entry associated with newKey, it must be 8510** discarded. ^Any prior cache entry associated with newKey is guaranteed not 8511** to be pinned. 8512** 8513** When SQLite calls the xTruncate() method, the cache must discard all 8514** existing cache entries with page numbers (keys) greater than or equal 8515** to the value of the iLimit parameter passed to xTruncate(). If any 8516** of these pages are pinned, they are implicitly unpinned, meaning that 8517** they can be safely discarded. 8518** 8519** [[the xDestroy() page cache method]] 8520** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 8521** All resources associated with the specified cache should be freed. ^After 8522** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 8523** handle invalid, and will not use it with any other sqlite3_pcache_methods2 8524** functions. 8525** 8526** [[the xShrink() page cache method]] 8527** ^SQLite invokes the xShrink() method when it wants the page cache to 8528** free up as much of heap memory as possible. The page cache implementation 8529** is not obligated to free any memory, but well-behaved implementations should 8530** do their best. 8531*/ 8532typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 8533struct sqlite3_pcache_methods2 { 8534 int iVersion; 8535 void *pArg; 8536 int (*xInit)(void*); 8537 void (*xShutdown)(void*); 8538 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 8539 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8540 int (*xPagecount)(sqlite3_pcache*); 8541 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8542 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 8543 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 8544 unsigned oldKey, unsigned newKey); 8545 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8546 void (*xDestroy)(sqlite3_pcache*); 8547 void (*xShrink)(sqlite3_pcache*); 8548}; 8549 8550/* 8551** This is the obsolete pcache_methods object that has now been replaced 8552** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 8553** retained in the header file for backwards compatibility only. 8554*/ 8555typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 8556struct sqlite3_pcache_methods { 8557 void *pArg; 8558 int (*xInit)(void*); 8559 void (*xShutdown)(void*); 8560 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 8561 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8562 int (*xPagecount)(sqlite3_pcache*); 8563 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8564 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 8565 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 8566 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8567 void (*xDestroy)(sqlite3_pcache*); 8568}; 8569 8570 8571/* 8572** CAPI3REF: Online Backup Object 8573** 8574** The sqlite3_backup object records state information about an ongoing 8575** online backup operation. ^The sqlite3_backup object is created by 8576** a call to [sqlite3_backup_init()] and is destroyed by a call to 8577** [sqlite3_backup_finish()]. 8578** 8579** See Also: [Using the SQLite Online Backup API] 8580*/ 8581typedef struct sqlite3_backup sqlite3_backup; 8582 8583/* 8584** CAPI3REF: Online Backup API. 8585** 8586** The backup API copies the content of one database into another. 8587** It is useful either for creating backups of databases or 8588** for copying in-memory databases to or from persistent files. 8589** 8590** See Also: [Using the SQLite Online Backup API] 8591** 8592** ^SQLite holds a write transaction open on the destination database file 8593** for the duration of the backup operation. 8594** ^The source database is read-locked only while it is being read; 8595** it is not locked continuously for the entire backup operation. 8596** ^Thus, the backup may be performed on a live source database without 8597** preventing other database connections from 8598** reading or writing to the source database while the backup is underway. 8599** 8600** ^(To perform a backup operation: 8601** <ol> 8602** <li><b>sqlite3_backup_init()</b> is called once to initialize the 8603** backup, 8604** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 8605** the data between the two databases, and finally 8606** <li><b>sqlite3_backup_finish()</b> is called to release all resources 8607** associated with the backup operation. 8608** </ol>)^ 8609** There should be exactly one call to sqlite3_backup_finish() for each 8610** successful call to sqlite3_backup_init(). 8611** 8612** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 8613** 8614** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 8615** [database connection] associated with the destination database 8616** and the database name, respectively. 8617** ^The database name is "main" for the main database, "temp" for the 8618** temporary database, or the name specified after the AS keyword in 8619** an [ATTACH] statement for an attached database. 8620** ^The S and M arguments passed to 8621** sqlite3_backup_init(D,N,S,M) identify the [database connection] 8622** and database name of the source database, respectively. 8623** ^The source and destination [database connections] (parameters S and D) 8624** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 8625** an error. 8626** 8627** ^A call to sqlite3_backup_init() will fail, returning NULL, if 8628** there is already a read or read-write transaction open on the 8629** destination database. 8630** 8631** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 8632** returned and an error code and error message are stored in the 8633** destination [database connection] D. 8634** ^The error code and message for the failed call to sqlite3_backup_init() 8635** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 8636** [sqlite3_errmsg16()] functions. 8637** ^A successful call to sqlite3_backup_init() returns a pointer to an 8638** [sqlite3_backup] object. 8639** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 8640** sqlite3_backup_finish() functions to perform the specified backup 8641** operation. 8642** 8643** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 8644** 8645** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 8646** the source and destination databases specified by [sqlite3_backup] object B. 8647** ^If N is negative, all remaining source pages are copied. 8648** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 8649** are still more pages to be copied, then the function returns [SQLITE_OK]. 8650** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 8651** from source to destination, then it returns [SQLITE_DONE]. 8652** ^If an error occurs while running sqlite3_backup_step(B,N), 8653** then an [error code] is returned. ^As well as [SQLITE_OK] and 8654** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 8655** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 8656** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 8657** 8658** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 8659** <ol> 8660** <li> the destination database was opened read-only, or 8661** <li> the destination database is using write-ahead-log journaling 8662** and the destination and source page sizes differ, or 8663** <li> the destination database is an in-memory database and the 8664** destination and source page sizes differ. 8665** </ol>)^ 8666** 8667** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 8668** the [sqlite3_busy_handler | busy-handler function] 8669** is invoked (if one is specified). ^If the 8670** busy-handler returns non-zero before the lock is available, then 8671** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 8672** sqlite3_backup_step() can be retried later. ^If the source 8673** [database connection] 8674** is being used to write to the source database when sqlite3_backup_step() 8675** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 8676** case the call to sqlite3_backup_step() can be retried later on. ^(If 8677** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 8678** [SQLITE_READONLY] is returned, then 8679** there is no point in retrying the call to sqlite3_backup_step(). These 8680** errors are considered fatal.)^ The application must accept 8681** that the backup operation has failed and pass the backup operation handle 8682** to the sqlite3_backup_finish() to release associated resources. 8683** 8684** ^The first call to sqlite3_backup_step() obtains an exclusive lock 8685** on the destination file. ^The exclusive lock is not released until either 8686** sqlite3_backup_finish() is called or the backup operation is complete 8687** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 8688** sqlite3_backup_step() obtains a [shared lock] on the source database that 8689** lasts for the duration of the sqlite3_backup_step() call. 8690** ^Because the source database is not locked between calls to 8691** sqlite3_backup_step(), the source database may be modified mid-way 8692** through the backup process. ^If the source database is modified by an 8693** external process or via a database connection other than the one being 8694** used by the backup operation, then the backup will be automatically 8695** restarted by the next call to sqlite3_backup_step(). ^If the source 8696** database is modified by the using the same database connection as is used 8697** by the backup operation, then the backup database is automatically 8698** updated at the same time. 8699** 8700** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 8701** 8702** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 8703** application wishes to abandon the backup operation, the application 8704** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 8705** ^The sqlite3_backup_finish() interfaces releases all 8706** resources associated with the [sqlite3_backup] object. 8707** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 8708** active write-transaction on the destination database is rolled back. 8709** The [sqlite3_backup] object is invalid 8710** and may not be used following a call to sqlite3_backup_finish(). 8711** 8712** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 8713** sqlite3_backup_step() errors occurred, regardless or whether or not 8714** sqlite3_backup_step() completed. 8715** ^If an out-of-memory condition or IO error occurred during any prior 8716** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 8717** sqlite3_backup_finish() returns the corresponding [error code]. 8718** 8719** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 8720** is not a permanent error and does not affect the return value of 8721** sqlite3_backup_finish(). 8722** 8723** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 8724** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 8725** 8726** ^The sqlite3_backup_remaining() routine returns the number of pages still 8727** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 8728** ^The sqlite3_backup_pagecount() routine returns the total number of pages 8729** in the source database at the conclusion of the most recent 8730** sqlite3_backup_step(). 8731** ^(The values returned by these functions are only updated by 8732** sqlite3_backup_step(). If the source database is modified in a way that 8733** changes the size of the source database or the number of pages remaining, 8734** those changes are not reflected in the output of sqlite3_backup_pagecount() 8735** and sqlite3_backup_remaining() until after the next 8736** sqlite3_backup_step().)^ 8737** 8738** <b>Concurrent Usage of Database Handles</b> 8739** 8740** ^The source [database connection] may be used by the application for other 8741** purposes while a backup operation is underway or being initialized. 8742** ^If SQLite is compiled and configured to support threadsafe database 8743** connections, then the source database connection may be used concurrently 8744** from within other threads. 8745** 8746** However, the application must guarantee that the destination 8747** [database connection] is not passed to any other API (by any thread) after 8748** sqlite3_backup_init() is called and before the corresponding call to 8749** sqlite3_backup_finish(). SQLite does not currently check to see 8750** if the application incorrectly accesses the destination [database connection] 8751** and so no error code is reported, but the operations may malfunction 8752** nevertheless. Use of the destination database connection while a 8753** backup is in progress might also also cause a mutex deadlock. 8754** 8755** If running in [shared cache mode], the application must 8756** guarantee that the shared cache used by the destination database 8757** is not accessed while the backup is running. In practice this means 8758** that the application must guarantee that the disk file being 8759** backed up to is not accessed by any connection within the process, 8760** not just the specific connection that was passed to sqlite3_backup_init(). 8761** 8762** The [sqlite3_backup] object itself is partially threadsafe. Multiple 8763** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 8764** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 8765** APIs are not strictly speaking threadsafe. If they are invoked at the 8766** same time as another thread is invoking sqlite3_backup_step() it is 8767** possible that they return invalid values. 8768*/ 8769sqlite3_backup *sqlite3_backup_init( 8770 sqlite3 *pDest, /* Destination database handle */ 8771 const char *zDestName, /* Destination database name */ 8772 sqlite3 *pSource, /* Source database handle */ 8773 const char *zSourceName /* Source database name */ 8774); 8775int sqlite3_backup_step(sqlite3_backup *p, int nPage); 8776int sqlite3_backup_finish(sqlite3_backup *p); 8777int sqlite3_backup_remaining(sqlite3_backup *p); 8778int sqlite3_backup_pagecount(sqlite3_backup *p); 8779 8780/* 8781** CAPI3REF: Unlock Notification 8782** METHOD: sqlite3 8783** 8784** ^When running in shared-cache mode, a database operation may fail with 8785** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 8786** individual tables within the shared-cache cannot be obtained. See 8787** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 8788** ^This API may be used to register a callback that SQLite will invoke 8789** when the connection currently holding the required lock relinquishes it. 8790** ^This API is only available if the library was compiled with the 8791** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 8792** 8793** See Also: [Using the SQLite Unlock Notification Feature]. 8794** 8795** ^Shared-cache locks are released when a database connection concludes 8796** its current transaction, either by committing it or rolling it back. 8797** 8798** ^When a connection (known as the blocked connection) fails to obtain a 8799** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 8800** identity of the database connection (the blocking connection) that 8801** has locked the required resource is stored internally. ^After an 8802** application receives an SQLITE_LOCKED error, it may call the 8803** sqlite3_unlock_notify() method with the blocked connection handle as 8804** the first argument to register for a callback that will be invoked 8805** when the blocking connections current transaction is concluded. ^The 8806** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 8807** call that concludes the blocking connection's transaction. 8808** 8809** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 8810** there is a chance that the blocking connection will have already 8811** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 8812** If this happens, then the specified callback is invoked immediately, 8813** from within the call to sqlite3_unlock_notify().)^ 8814** 8815** ^If the blocked connection is attempting to obtain a write-lock on a 8816** shared-cache table, and more than one other connection currently holds 8817** a read-lock on the same table, then SQLite arbitrarily selects one of 8818** the other connections to use as the blocking connection. 8819** 8820** ^(There may be at most one unlock-notify callback registered by a 8821** blocked connection. If sqlite3_unlock_notify() is called when the 8822** blocked connection already has a registered unlock-notify callback, 8823** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 8824** called with a NULL pointer as its second argument, then any existing 8825** unlock-notify callback is canceled. ^The blocked connections 8826** unlock-notify callback may also be canceled by closing the blocked 8827** connection using [sqlite3_close()]. 8828** 8829** The unlock-notify callback is not reentrant. If an application invokes 8830** any sqlite3_xxx API functions from within an unlock-notify callback, a 8831** crash or deadlock may be the result. 8832** 8833** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 8834** returns SQLITE_OK. 8835** 8836** <b>Callback Invocation Details</b> 8837** 8838** When an unlock-notify callback is registered, the application provides a 8839** single void* pointer that is passed to the callback when it is invoked. 8840** However, the signature of the callback function allows SQLite to pass 8841** it an array of void* context pointers. The first argument passed to 8842** an unlock-notify callback is a pointer to an array of void* pointers, 8843** and the second is the number of entries in the array. 8844** 8845** When a blocking connection's transaction is concluded, there may be 8846** more than one blocked connection that has registered for an unlock-notify 8847** callback. ^If two or more such blocked connections have specified the 8848** same callback function, then instead of invoking the callback function 8849** multiple times, it is invoked once with the set of void* context pointers 8850** specified by the blocked connections bundled together into an array. 8851** This gives the application an opportunity to prioritize any actions 8852** related to the set of unblocked database connections. 8853** 8854** <b>Deadlock Detection</b> 8855** 8856** Assuming that after registering for an unlock-notify callback a 8857** database waits for the callback to be issued before taking any further 8858** action (a reasonable assumption), then using this API may cause the 8859** application to deadlock. For example, if connection X is waiting for 8860** connection Y's transaction to be concluded, and similarly connection 8861** Y is waiting on connection X's transaction, then neither connection 8862** will proceed and the system may remain deadlocked indefinitely. 8863** 8864** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 8865** detection. ^If a given call to sqlite3_unlock_notify() would put the 8866** system in a deadlocked state, then SQLITE_LOCKED is returned and no 8867** unlock-notify callback is registered. The system is said to be in 8868** a deadlocked state if connection A has registered for an unlock-notify 8869** callback on the conclusion of connection B's transaction, and connection 8870** B has itself registered for an unlock-notify callback when connection 8871** A's transaction is concluded. ^Indirect deadlock is also detected, so 8872** the system is also considered to be deadlocked if connection B has 8873** registered for an unlock-notify callback on the conclusion of connection 8874** C's transaction, where connection C is waiting on connection A. ^Any 8875** number of levels of indirection are allowed. 8876** 8877** <b>The "DROP TABLE" Exception</b> 8878** 8879** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 8880** always appropriate to call sqlite3_unlock_notify(). There is however, 8881** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 8882** SQLite checks if there are any currently executing SELECT statements 8883** that belong to the same connection. If there are, SQLITE_LOCKED is 8884** returned. In this case there is no "blocking connection", so invoking 8885** sqlite3_unlock_notify() results in the unlock-notify callback being 8886** invoked immediately. If the application then re-attempts the "DROP TABLE" 8887** or "DROP INDEX" query, an infinite loop might be the result. 8888** 8889** One way around this problem is to check the extended error code returned 8890** by an sqlite3_step() call. ^(If there is a blocking connection, then the 8891** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 8892** the special "DROP TABLE/INDEX" case, the extended error code is just 8893** SQLITE_LOCKED.)^ 8894*/ 8895int sqlite3_unlock_notify( 8896 sqlite3 *pBlocked, /* Waiting connection */ 8897 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 8898 void *pNotifyArg /* Argument to pass to xNotify */ 8899); 8900 8901 8902/* 8903** CAPI3REF: String Comparison 8904** 8905** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 8906** and extensions to compare the contents of two buffers containing UTF-8 8907** strings in a case-independent fashion, using the same definition of "case 8908** independence" that SQLite uses internally when comparing identifiers. 8909*/ 8910int sqlite3_stricmp(const char *, const char *); 8911int sqlite3_strnicmp(const char *, const char *, int); 8912 8913/* 8914** CAPI3REF: String Globbing 8915* 8916** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 8917** string X matches the [GLOB] pattern P. 8918** ^The definition of [GLOB] pattern matching used in 8919** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 8920** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 8921** is case sensitive. 8922** 8923** Note that this routine returns zero on a match and non-zero if the strings 8924** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8925** 8926** See also: [sqlite3_strlike()]. 8927*/ 8928int sqlite3_strglob(const char *zGlob, const char *zStr); 8929 8930/* 8931** CAPI3REF: String LIKE Matching 8932* 8933** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 8934** string X matches the [LIKE] pattern P with escape character E. 8935** ^The definition of [LIKE] pattern matching used in 8936** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 8937** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 8938** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 8939** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 8940** insensitive - equivalent upper and lower case ASCII characters match 8941** one another. 8942** 8943** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 8944** only ASCII characters are case folded. 8945** 8946** Note that this routine returns zero on a match and non-zero if the strings 8947** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8948** 8949** See also: [sqlite3_strglob()]. 8950*/ 8951int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8952 8953/* 8954** CAPI3REF: Error Logging Interface 8955** 8956** ^The [sqlite3_log()] interface writes a message into the [error log] 8957** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8958** ^If logging is enabled, the zFormat string and subsequent arguments are 8959** used with [sqlite3_snprintf()] to generate the final output string. 8960** 8961** The sqlite3_log() interface is intended for use by extensions such as 8962** virtual tables, collating functions, and SQL functions. While there is 8963** nothing to prevent an application from calling sqlite3_log(), doing so 8964** is considered bad form. 8965** 8966** The zFormat string must not be NULL. 8967** 8968** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8969** will not use dynamically allocated memory. The log message is stored in 8970** a fixed-length buffer on the stack. If the log message is longer than 8971** a few hundred characters, it will be truncated to the length of the 8972** buffer. 8973*/ 8974void sqlite3_log(int iErrCode, const char *zFormat, ...); 8975 8976/* 8977** CAPI3REF: Write-Ahead Log Commit Hook 8978** METHOD: sqlite3 8979** 8980** ^The [sqlite3_wal_hook()] function is used to register a callback that 8981** is invoked each time data is committed to a database in wal mode. 8982** 8983** ^(The callback is invoked by SQLite after the commit has taken place and 8984** the associated write-lock on the database released)^, so the implementation 8985** may read, write or [checkpoint] the database as required. 8986** 8987** ^The first parameter passed to the callback function when it is invoked 8988** is a copy of the third parameter passed to sqlite3_wal_hook() when 8989** registering the callback. ^The second is a copy of the database handle. 8990** ^The third parameter is the name of the database that was written to - 8991** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8992** is the number of pages currently in the write-ahead log file, 8993** including those that were just committed. 8994** 8995** The callback function should normally return [SQLITE_OK]. ^If an error 8996** code is returned, that error will propagate back up through the 8997** SQLite code base to cause the statement that provoked the callback 8998** to report an error, though the commit will have still occurred. If the 8999** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 9000** that does not correspond to any valid SQLite error code, the results 9001** are undefined. 9002** 9003** A single database handle may have at most a single write-ahead log callback 9004** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 9005** previously registered write-ahead log callback. ^Note that the 9006** [sqlite3_wal_autocheckpoint()] interface and the 9007** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 9008** overwrite any prior [sqlite3_wal_hook()] settings. 9009*/ 9010void *sqlite3_wal_hook( 9011 sqlite3*, 9012 int(*)(void *,sqlite3*,const char*,int), 9013 void* 9014); 9015 9016/* 9017** CAPI3REF: Configure an auto-checkpoint 9018** METHOD: sqlite3 9019** 9020** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 9021** [sqlite3_wal_hook()] that causes any database on [database connection] D 9022** to automatically [checkpoint] 9023** after committing a transaction if there are N or 9024** more frames in the [write-ahead log] file. ^Passing zero or 9025** a negative value as the nFrame parameter disables automatic 9026** checkpoints entirely. 9027** 9028** ^The callback registered by this function replaces any existing callback 9029** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 9030** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 9031** configured by this function. 9032** 9033** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 9034** from SQL. 9035** 9036** ^Checkpoints initiated by this mechanism are 9037** [sqlite3_wal_checkpoint_v2|PASSIVE]. 9038** 9039** ^Every new [database connection] defaults to having the auto-checkpoint 9040** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 9041** pages. The use of this interface 9042** is only necessary if the default setting is found to be suboptimal 9043** for a particular application. 9044*/ 9045int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 9046 9047/* 9048** CAPI3REF: Checkpoint a database 9049** METHOD: sqlite3 9050** 9051** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 9052** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 9053** 9054** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 9055** [write-ahead log] for database X on [database connection] D to be 9056** transferred into the database file and for the write-ahead log to 9057** be reset. See the [checkpointing] documentation for addition 9058** information. 9059** 9060** This interface used to be the only way to cause a checkpoint to 9061** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 9062** interface was added. This interface is retained for backwards 9063** compatibility and as a convenience for applications that need to manually 9064** start a callback but which do not need the full power (and corresponding 9065** complication) of [sqlite3_wal_checkpoint_v2()]. 9066*/ 9067int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 9068 9069/* 9070** CAPI3REF: Checkpoint a database 9071** METHOD: sqlite3 9072** 9073** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 9074** operation on database X of [database connection] D in mode M. Status 9075** information is written back into integers pointed to by L and C.)^ 9076** ^(The M parameter must be a valid [checkpoint mode]:)^ 9077** 9078** <dl> 9079** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 9080** ^Checkpoint as many frames as possible without waiting for any database 9081** readers or writers to finish, then sync the database file if all frames 9082** in the log were checkpointed. ^The [busy-handler callback] 9083** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 9084** ^On the other hand, passive mode might leave the checkpoint unfinished 9085** if there are concurrent readers or writers. 9086** 9087** <dt>SQLITE_CHECKPOINT_FULL<dd> 9088** ^This mode blocks (it invokes the 9089** [sqlite3_busy_handler|busy-handler callback]) until there is no 9090** database writer and all readers are reading from the most recent database 9091** snapshot. ^It then checkpoints all frames in the log file and syncs the 9092** database file. ^This mode blocks new database writers while it is pending, 9093** but new database readers are allowed to continue unimpeded. 9094** 9095** <dt>SQLITE_CHECKPOINT_RESTART<dd> 9096** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 9097** that after checkpointing the log file it blocks (calls the 9098** [busy-handler callback]) 9099** until all readers are reading from the database file only. ^This ensures 9100** that the next writer will restart the log file from the beginning. 9101** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 9102** database writer attempts while it is pending, but does not impede readers. 9103** 9104** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 9105** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 9106** addition that it also truncates the log file to zero bytes just prior 9107** to a successful return. 9108** </dl> 9109** 9110** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 9111** the log file or to -1 if the checkpoint could not run because 9112** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 9113** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 9114** log file (including any that were already checkpointed before the function 9115** was called) or to -1 if the checkpoint could not run due to an error or 9116** because the database is not in WAL mode. ^Note that upon successful 9117** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 9118** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 9119** 9120** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 9121** any other process is running a checkpoint operation at the same time, the 9122** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 9123** busy-handler configured, it will not be invoked in this case. 9124** 9125** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 9126** exclusive "writer" lock on the database file. ^If the writer lock cannot be 9127** obtained immediately, and a busy-handler is configured, it is invoked and 9128** the writer lock retried until either the busy-handler returns 0 or the lock 9129** is successfully obtained. ^The busy-handler is also invoked while waiting for 9130** database readers as described above. ^If the busy-handler returns 0 before 9131** the writer lock is obtained or while waiting for database readers, the 9132** checkpoint operation proceeds from that point in the same way as 9133** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 9134** without blocking any further. ^SQLITE_BUSY is returned in this case. 9135** 9136** ^If parameter zDb is NULL or points to a zero length string, then the 9137** specified operation is attempted on all WAL databases [attached] to 9138** [database connection] db. In this case the 9139** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 9140** an SQLITE_BUSY error is encountered when processing one or more of the 9141** attached WAL databases, the operation is still attempted on any remaining 9142** attached databases and SQLITE_BUSY is returned at the end. ^If any other 9143** error occurs while processing an attached database, processing is abandoned 9144** and the error code is returned to the caller immediately. ^If no error 9145** (SQLITE_BUSY or otherwise) is encountered while processing the attached 9146** databases, SQLITE_OK is returned. 9147** 9148** ^If database zDb is the name of an attached database that is not in WAL 9149** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 9150** zDb is not NULL (or a zero length string) and is not the name of any 9151** attached database, SQLITE_ERROR is returned to the caller. 9152** 9153** ^Unless it returns SQLITE_MISUSE, 9154** the sqlite3_wal_checkpoint_v2() interface 9155** sets the error information that is queried by 9156** [sqlite3_errcode()] and [sqlite3_errmsg()]. 9157** 9158** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 9159** from SQL. 9160*/ 9161int sqlite3_wal_checkpoint_v2( 9162 sqlite3 *db, /* Database handle */ 9163 const char *zDb, /* Name of attached database (or NULL) */ 9164 int eMode, /* SQLITE_CHECKPOINT_* value */ 9165 int *pnLog, /* OUT: Size of WAL log in frames */ 9166 int *pnCkpt /* OUT: Total number of frames checkpointed */ 9167); 9168 9169/* 9170** CAPI3REF: Checkpoint Mode Values 9171** KEYWORDS: {checkpoint mode} 9172** 9173** These constants define all valid values for the "checkpoint mode" passed 9174** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 9175** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 9176** meaning of each of these checkpoint modes. 9177*/ 9178#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 9179#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 9180#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 9181#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 9182 9183/* 9184** CAPI3REF: Virtual Table Interface Configuration 9185** 9186** This function may be called by either the [xConnect] or [xCreate] method 9187** of a [virtual table] implementation to configure 9188** various facets of the virtual table interface. 9189** 9190** If this interface is invoked outside the context of an xConnect or 9191** xCreate virtual table method then the behavior is undefined. 9192** 9193** In the call sqlite3_vtab_config(D,C,...) the D parameter is the 9194** [database connection] in which the virtual table is being created and 9195** which is passed in as the first argument to the [xConnect] or [xCreate] 9196** method that is invoking sqlite3_vtab_config(). The C parameter is one 9197** of the [virtual table configuration options]. The presence and meaning 9198** of parameters after C depend on which [virtual table configuration option] 9199** is used. 9200*/ 9201int sqlite3_vtab_config(sqlite3*, int op, ...); 9202 9203/* 9204** CAPI3REF: Virtual Table Configuration Options 9205** KEYWORDS: {virtual table configuration options} 9206** KEYWORDS: {virtual table configuration option} 9207** 9208** These macros define the various options to the 9209** [sqlite3_vtab_config()] interface that [virtual table] implementations 9210** can use to customize and optimize their behavior. 9211** 9212** <dl> 9213** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]] 9214** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt> 9215** <dd>Calls of the form 9216** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 9217** where X is an integer. If X is zero, then the [virtual table] whose 9218** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 9219** support constraints. In this configuration (which is the default) if 9220** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 9221** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 9222** specified as part of the users SQL statement, regardless of the actual 9223** ON CONFLICT mode specified. 9224** 9225** If X is non-zero, then the virtual table implementation guarantees 9226** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 9227** any modifications to internal or persistent data structures have been made. 9228** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 9229** is able to roll back a statement or database transaction, and abandon 9230** or continue processing the current SQL statement as appropriate. 9231** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 9232** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 9233** had been ABORT. 9234** 9235** Virtual table implementations that are required to handle OR REPLACE 9236** must do so within the [xUpdate] method. If a call to the 9237** [sqlite3_vtab_on_conflict()] function indicates that the current ON 9238** CONFLICT policy is REPLACE, the virtual table implementation should 9239** silently replace the appropriate rows within the xUpdate callback and 9240** return SQLITE_OK. Or, if this is not possible, it may return 9241** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 9242** constraint handling. 9243** </dd> 9244** 9245** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt> 9246** <dd>Calls of the form 9247** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the 9248** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9249** prohibits that virtual table from being used from within triggers and 9250** views. 9251** </dd> 9252** 9253** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt> 9254** <dd>Calls of the form 9255** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the 9256** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9257** identify that virtual table as being safe to use from within triggers 9258** and views. Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the 9259** virtual table can do no serious harm even if it is controlled by a 9260** malicious hacker. Developers should avoid setting the SQLITE_VTAB_INNOCUOUS 9261** flag unless absolutely necessary. 9262** </dd> 9263** </dl> 9264*/ 9265#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 9266#define SQLITE_VTAB_INNOCUOUS 2 9267#define SQLITE_VTAB_DIRECTONLY 3 9268 9269/* 9270** CAPI3REF: Determine The Virtual Table Conflict Policy 9271** 9272** This function may only be called from within a call to the [xUpdate] method 9273** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 9274** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 9275** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 9276** of the SQL statement that triggered the call to the [xUpdate] method of the 9277** [virtual table]. 9278*/ 9279int sqlite3_vtab_on_conflict(sqlite3 *); 9280 9281/* 9282** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 9283** 9284** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 9285** method of a [virtual table], then it might return true if the 9286** column is being fetched as part of an UPDATE operation during which the 9287** column value will not change. The virtual table implementation can use 9288** this hint as permission to substitute a return value that is less 9289** expensive to compute and that the corresponding 9290** [xUpdate] method understands as a "no-change" value. 9291** 9292** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 9293** the column is not changed by the UPDATE statement, then the xColumn 9294** method can optionally return without setting a result, without calling 9295** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 9296** In that case, [sqlite3_value_nochange(X)] will return true for the 9297** same column in the [xUpdate] method. 9298** 9299** The sqlite3_vtab_nochange() routine is an optimization. Virtual table 9300** implementations should continue to give a correct answer even if the 9301** sqlite3_vtab_nochange() interface were to always return false. In the 9302** current implementation, the sqlite3_vtab_nochange() interface does always 9303** returns false for the enhanced [UPDATE FROM] statement. 9304*/ 9305int sqlite3_vtab_nochange(sqlite3_context*); 9306 9307/* 9308** CAPI3REF: Determine The Collation For a Virtual Table Constraint 9309** 9310** This function may only be called from within a call to the [xBestIndex] 9311** method of a [virtual table]. 9312** 9313** The first argument must be the sqlite3_index_info object that is the 9314** first parameter to the xBestIndex() method. The second argument must be 9315** an index into the aConstraint[] array belonging to the sqlite3_index_info 9316** structure passed to xBestIndex. This function returns a pointer to a buffer 9317** containing the name of the collation sequence for the corresponding 9318** constraint. 9319*/ 9320SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 9321 9322/* 9323** CAPI3REF: Conflict resolution modes 9324** KEYWORDS: {conflict resolution mode} 9325** 9326** These constants are returned by [sqlite3_vtab_on_conflict()] to 9327** inform a [virtual table] implementation what the [ON CONFLICT] mode 9328** is for the SQL statement being evaluated. 9329** 9330** Note that the [SQLITE_IGNORE] constant is also used as a potential 9331** return value from the [sqlite3_set_authorizer()] callback and that 9332** [SQLITE_ABORT] is also a [result code]. 9333*/ 9334#define SQLITE_ROLLBACK 1 9335/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 9336#define SQLITE_FAIL 3 9337/* #define SQLITE_ABORT 4 // Also an error code */ 9338#define SQLITE_REPLACE 5 9339 9340/* 9341** CAPI3REF: Prepared Statement Scan Status Opcodes 9342** KEYWORDS: {scanstatus options} 9343** 9344** The following constants can be used for the T parameter to the 9345** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 9346** different metric for sqlite3_stmt_scanstatus() to return. 9347** 9348** When the value returned to V is a string, space to hold that string is 9349** managed by the prepared statement S and will be automatically freed when 9350** S is finalized. 9351** 9352** <dl> 9353** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 9354** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be 9355** set to the total number of times that the X-th loop has run.</dd> 9356** 9357** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 9358** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set 9359** to the total number of rows examined by all iterations of the X-th loop.</dd> 9360** 9361** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 9362** <dd>^The "double" variable pointed to by the V parameter will be set to the 9363** query planner's estimate for the average number of rows output from each 9364** iteration of the X-th loop. If the query planner's estimates was accurate, 9365** then this value will approximate the quotient NVISIT/NLOOP and the 9366** product of this value for all prior loops with the same SELECTID will 9367** be the NLOOP value for the current loop. 9368** 9369** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 9370** <dd>^The "const char *" variable pointed to by the V parameter will be set 9371** to a zero-terminated UTF-8 string containing the name of the index or table 9372** used for the X-th loop. 9373** 9374** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 9375** <dd>^The "const char *" variable pointed to by the V parameter will be set 9376** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 9377** description for the X-th loop. 9378** 9379** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 9380** <dd>^The "int" variable pointed to by the V parameter will be set to the 9381** "select-id" for the X-th loop. The select-id identifies which query or 9382** subquery the loop is part of. The main query has a select-id of zero. 9383** The select-id is the same value as is output in the first column 9384** of an [EXPLAIN QUERY PLAN] query. 9385** </dl> 9386*/ 9387#define SQLITE_SCANSTAT_NLOOP 0 9388#define SQLITE_SCANSTAT_NVISIT 1 9389#define SQLITE_SCANSTAT_EST 2 9390#define SQLITE_SCANSTAT_NAME 3 9391#define SQLITE_SCANSTAT_EXPLAIN 4 9392#define SQLITE_SCANSTAT_SELECTID 5 9393 9394/* 9395** CAPI3REF: Prepared Statement Scan Status 9396** METHOD: sqlite3_stmt 9397** 9398** This interface returns information about the predicted and measured 9399** performance for pStmt. Advanced applications can use this 9400** interface to compare the predicted and the measured performance and 9401** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 9402** 9403** Since this interface is expected to be rarely used, it is only 9404** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 9405** compile-time option. 9406** 9407** The "iScanStatusOp" parameter determines which status information to return. 9408** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 9409** of this interface is undefined. 9410** ^The requested measurement is written into a variable pointed to by 9411** the "pOut" parameter. 9412** Parameter "idx" identifies the specific loop to retrieve statistics for. 9413** Loops are numbered starting from zero. ^If idx is out of range - less than 9414** zero or greater than or equal to the total number of loops used to implement 9415** the statement - a non-zero value is returned and the variable that pOut 9416** points to is unchanged. 9417** 9418** ^Statistics might not be available for all loops in all statements. ^In cases 9419** where there exist loops with no available statistics, this function behaves 9420** as if the loop did not exist - it returns non-zero and leave the variable 9421** that pOut points to unchanged. 9422** 9423** See also: [sqlite3_stmt_scanstatus_reset()] 9424*/ 9425int sqlite3_stmt_scanstatus( 9426 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 9427 int idx, /* Index of loop to report on */ 9428 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 9429 void *pOut /* Result written here */ 9430); 9431 9432/* 9433** CAPI3REF: Zero Scan-Status Counters 9434** METHOD: sqlite3_stmt 9435** 9436** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 9437** 9438** This API is only available if the library is built with pre-processor 9439** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 9440*/ 9441void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 9442 9443/* 9444** CAPI3REF: Flush caches to disk mid-transaction 9445** METHOD: sqlite3 9446** 9447** ^If a write-transaction is open on [database connection] D when the 9448** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 9449** pages in the pager-cache that are not currently in use are written out 9450** to disk. A dirty page may be in use if a database cursor created by an 9451** active SQL statement is reading from it, or if it is page 1 of a database 9452** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 9453** interface flushes caches for all schemas - "main", "temp", and 9454** any [attached] databases. 9455** 9456** ^If this function needs to obtain extra database locks before dirty pages 9457** can be flushed to disk, it does so. ^If those locks cannot be obtained 9458** immediately and there is a busy-handler callback configured, it is invoked 9459** in the usual manner. ^If the required lock still cannot be obtained, then 9460** the database is skipped and an attempt made to flush any dirty pages 9461** belonging to the next (if any) database. ^If any databases are skipped 9462** because locks cannot be obtained, but no other error occurs, this 9463** function returns SQLITE_BUSY. 9464** 9465** ^If any other error occurs while flushing dirty pages to disk (for 9466** example an IO error or out-of-memory condition), then processing is 9467** abandoned and an SQLite [error code] is returned to the caller immediately. 9468** 9469** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 9470** 9471** ^This function does not set the database handle error code or message 9472** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 9473*/ 9474int sqlite3_db_cacheflush(sqlite3*); 9475 9476/* 9477** CAPI3REF: The pre-update hook. 9478** METHOD: sqlite3 9479** 9480** ^These interfaces are only available if SQLite is compiled using the 9481** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 9482** 9483** ^The [sqlite3_preupdate_hook()] interface registers a callback function 9484** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 9485** on a database table. 9486** ^At most one preupdate hook may be registered at a time on a single 9487** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 9488** the previous setting. 9489** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 9490** with a NULL pointer as the second parameter. 9491** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 9492** the first parameter to callbacks. 9493** 9494** ^The preupdate hook only fires for changes to real database tables; the 9495** preupdate hook is not invoked for changes to [virtual tables] or to 9496** system tables like sqlite_sequence or sqlite_stat1. 9497** 9498** ^The second parameter to the preupdate callback is a pointer to 9499** the [database connection] that registered the preupdate hook. 9500** ^The third parameter to the preupdate callback is one of the constants 9501** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 9502** kind of update operation that is about to occur. 9503** ^(The fourth parameter to the preupdate callback is the name of the 9504** database within the database connection that is being modified. This 9505** will be "main" for the main database or "temp" for TEMP tables or 9506** the name given after the AS keyword in the [ATTACH] statement for attached 9507** databases.)^ 9508** ^The fifth parameter to the preupdate callback is the name of the 9509** table that is being modified. 9510** 9511** For an UPDATE or DELETE operation on a [rowid table], the sixth 9512** parameter passed to the preupdate callback is the initial [rowid] of the 9513** row being modified or deleted. For an INSERT operation on a rowid table, 9514** or any operation on a WITHOUT ROWID table, the value of the sixth 9515** parameter is undefined. For an INSERT or UPDATE on a rowid table the 9516** seventh parameter is the final rowid value of the row being inserted 9517** or updated. The value of the seventh parameter passed to the callback 9518** function is not defined for operations on WITHOUT ROWID tables, or for 9519** DELETE operations on rowid tables. 9520** 9521** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 9522** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 9523** provide additional information about a preupdate event. These routines 9524** may only be called from within a preupdate callback. Invoking any of 9525** these routines from outside of a preupdate callback or with a 9526** [database connection] pointer that is different from the one supplied 9527** to the preupdate callback results in undefined and probably undesirable 9528** behavior. 9529** 9530** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 9531** in the row that is being inserted, updated, or deleted. 9532** 9533** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 9534** a [protected sqlite3_value] that contains the value of the Nth column of 9535** the table row before it is updated. The N parameter must be between 0 9536** and one less than the number of columns or the behavior will be 9537** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 9538** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 9539** behavior is undefined. The [sqlite3_value] that P points to 9540** will be destroyed when the preupdate callback returns. 9541** 9542** ^The [sqlite3_preupdate_new(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 after 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_INSERT and SQLITE_UPDATE 9547** preupdate callbacks; if it is used by an SQLITE_DELETE 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_depth(D)] interface returns 0 if the preupdate 9552** callback was invoked as a result of a direct insert, update, or delete 9553** operation; or 1 for inserts, updates, or deletes invoked by top-level 9554** triggers; or 2 for changes resulting from triggers called by top-level 9555** triggers; and so forth. 9556** 9557** When the [sqlite3_blob_write()] API is used to update a blob column, 9558** the pre-update hook is invoked with SQLITE_DELETE. This is because the 9559** in this case the new values are not available. In this case, when a 9560** callback made with op==SQLITE_DELETE is actuall a write using the 9561** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns 9562** the index of the column being written. In other cases, where the 9563** pre-update hook is being invoked for some other reason, including a 9564** regular DELETE, sqlite3_preupdate_blobwrite() returns -1. 9565** 9566** See also: [sqlite3_update_hook()] 9567*/ 9568#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 9569void *sqlite3_preupdate_hook( 9570 sqlite3 *db, 9571 void(*xPreUpdate)( 9572 void *pCtx, /* Copy of third arg to preupdate_hook() */ 9573 sqlite3 *db, /* Database handle */ 9574 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 9575 char const *zDb, /* Database name */ 9576 char const *zName, /* Table name */ 9577 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 9578 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 9579 ), 9580 void* 9581); 9582int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 9583int sqlite3_preupdate_count(sqlite3 *); 9584int sqlite3_preupdate_depth(sqlite3 *); 9585int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 9586int sqlite3_preupdate_blobwrite(sqlite3 *); 9587#endif 9588 9589/* 9590** CAPI3REF: Low-level system error code 9591** METHOD: sqlite3 9592** 9593** ^Attempt to return the underlying operating system error code or error 9594** number that caused the most recent I/O error or failure to open a file. 9595** The return value is OS-dependent. For example, on unix systems, after 9596** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 9597** called to get back the underlying "errno" that caused the problem, such 9598** as ENOSPC, EAUTH, EISDIR, and so forth. 9599*/ 9600int sqlite3_system_errno(sqlite3*); 9601 9602/* 9603** CAPI3REF: Database Snapshot 9604** KEYWORDS: {snapshot} {sqlite3_snapshot} 9605** 9606** An instance of the snapshot object records the state of a [WAL mode] 9607** database for some specific point in history. 9608** 9609** In [WAL mode], multiple [database connections] that are open on the 9610** same database file can each be reading a different historical version 9611** of the database file. When a [database connection] begins a read 9612** transaction, that connection sees an unchanging copy of the database 9613** as it existed for the point in time when the transaction first started. 9614** Subsequent changes to the database from other connections are not seen 9615** by the reader until a new read transaction is started. 9616** 9617** The sqlite3_snapshot object records state information about an historical 9618** version of the database file so that it is possible to later open a new read 9619** transaction that sees that historical version of the database rather than 9620** the most recent version. 9621*/ 9622typedef struct sqlite3_snapshot { 9623 unsigned char hidden[48]; 9624} sqlite3_snapshot; 9625 9626/* 9627** CAPI3REF: Record A Database Snapshot 9628** CONSTRUCTOR: sqlite3_snapshot 9629** 9630** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 9631** new [sqlite3_snapshot] object that records the current state of 9632** schema S in database connection D. ^On success, the 9633** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 9634** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 9635** If there is not already a read-transaction open on schema S when 9636** this function is called, one is opened automatically. 9637** 9638** The following must be true for this function to succeed. If any of 9639** the following statements are false when sqlite3_snapshot_get() is 9640** called, SQLITE_ERROR is returned. The final value of *P is undefined 9641** in this case. 9642** 9643** <ul> 9644** <li> The database handle must not be in [autocommit mode]. 9645** 9646** <li> Schema S of [database connection] D must be a [WAL mode] database. 9647** 9648** <li> There must not be a write transaction open on schema S of database 9649** connection D. 9650** 9651** <li> One or more transactions must have been written to the current wal 9652** file since it was created on disk (by any connection). This means 9653** that a snapshot cannot be taken on a wal mode database with no wal 9654** file immediately after it is first opened. At least one transaction 9655** must be written to it first. 9656** </ul> 9657** 9658** This function may also return SQLITE_NOMEM. If it is called with the 9659** database handle in autocommit mode but fails for some other reason, 9660** whether or not a read transaction is opened on schema S is undefined. 9661** 9662** The [sqlite3_snapshot] object returned from a successful call to 9663** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 9664** to avoid a memory leak. 9665** 9666** The [sqlite3_snapshot_get()] interface is only available when the 9667** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9668*/ 9669SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 9670 sqlite3 *db, 9671 const char *zSchema, 9672 sqlite3_snapshot **ppSnapshot 9673); 9674 9675/* 9676** CAPI3REF: Start a read transaction on an historical snapshot 9677** METHOD: sqlite3_snapshot 9678** 9679** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read 9680** transaction or upgrades an existing one for schema S of 9681** [database connection] D such that the read transaction refers to 9682** historical [snapshot] P, rather than the most recent change to the 9683** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK 9684** on success or an appropriate [error code] if it fails. 9685** 9686** ^In order to succeed, the database connection must not be in 9687** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there 9688** is already a read transaction open on schema S, then the database handle 9689** must have no active statements (SELECT statements that have been passed 9690** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()). 9691** SQLITE_ERROR is returned if either of these conditions is violated, or 9692** if schema S does not exist, or if the snapshot object is invalid. 9693** 9694** ^A call to sqlite3_snapshot_open() will fail to open if the specified 9695** snapshot has been overwritten by a [checkpoint]. In this case 9696** SQLITE_ERROR_SNAPSHOT is returned. 9697** 9698** If there is already a read transaction open when this function is 9699** invoked, then the same read transaction remains open (on the same 9700** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT 9701** is returned. If another error code - for example SQLITE_PROTOCOL or an 9702** SQLITE_IOERR error code - is returned, then the final state of the 9703** read transaction is undefined. If SQLITE_OK is returned, then the 9704** read transaction is now open on database snapshot P. 9705** 9706** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 9707** database connection D does not know that the database file for 9708** schema S is in [WAL mode]. A database connection might not know 9709** that the database file is in [WAL mode] if there has been no prior 9710** I/O on that database connection, or if the database entered [WAL mode] 9711** after the most recent I/O on the database connection.)^ 9712** (Hint: Run "[PRAGMA application_id]" against a newly opened 9713** database connection in order to make it ready to use snapshots.) 9714** 9715** The [sqlite3_snapshot_open()] interface is only available when the 9716** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9717*/ 9718SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 9719 sqlite3 *db, 9720 const char *zSchema, 9721 sqlite3_snapshot *pSnapshot 9722); 9723 9724/* 9725** CAPI3REF: Destroy a snapshot 9726** DESTRUCTOR: sqlite3_snapshot 9727** 9728** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 9729** The application must eventually free every [sqlite3_snapshot] object 9730** using this routine to avoid a memory leak. 9731** 9732** The [sqlite3_snapshot_free()] interface is only available when the 9733** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9734*/ 9735SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 9736 9737/* 9738** CAPI3REF: Compare the ages of two snapshot handles. 9739** METHOD: sqlite3_snapshot 9740** 9741** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 9742** of two valid snapshot handles. 9743** 9744** If the two snapshot handles are not associated with the same database 9745** file, the result of the comparison is undefined. 9746** 9747** Additionally, the result of the comparison is only valid if both of the 9748** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 9749** last time the wal file was deleted. The wal file is deleted when the 9750** database is changed back to rollback mode or when the number of database 9751** clients drops to zero. If either snapshot handle was obtained before the 9752** wal file was last deleted, the value returned by this function 9753** is undefined. 9754** 9755** Otherwise, this API returns a negative value if P1 refers to an older 9756** snapshot than P2, zero if the two handles refer to the same database 9757** snapshot, and a positive value if P1 is a newer snapshot than P2. 9758** 9759** This interface is only available if SQLite is compiled with the 9760** [SQLITE_ENABLE_SNAPSHOT] option. 9761*/ 9762SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 9763 sqlite3_snapshot *p1, 9764 sqlite3_snapshot *p2 9765); 9766 9767/* 9768** CAPI3REF: Recover snapshots from a wal file 9769** METHOD: sqlite3_snapshot 9770** 9771** If a [WAL file] remains on disk after all database connections close 9772** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control] 9773** or because the last process to have the database opened exited without 9774** calling [sqlite3_close()]) and a new connection is subsequently opened 9775** on that database and [WAL file], the [sqlite3_snapshot_open()] interface 9776** will only be able to open the last transaction added to the WAL file 9777** even though the WAL file contains other valid transactions. 9778** 9779** This function attempts to scan the WAL file associated with database zDb 9780** of database handle db and make all valid snapshots available to 9781** sqlite3_snapshot_open(). It is an error if there is already a read 9782** transaction open on the database, or if the database is not a WAL mode 9783** database. 9784** 9785** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 9786** 9787** This interface is only available if SQLite is compiled with the 9788** [SQLITE_ENABLE_SNAPSHOT] option. 9789*/ 9790SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 9791 9792/* 9793** CAPI3REF: Serialize a database 9794** 9795** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 9796** that is a serialization of the S database on [database connection] D. 9797** If P is not a NULL pointer, then the size of the database in bytes 9798** is written into *P. 9799** 9800** For an ordinary on-disk database file, the serialization is just a 9801** copy of the disk file. For an in-memory database or a "TEMP" database, 9802** the serialization is the same sequence of bytes which would be written 9803** to disk if that database where backed up to disk. 9804** 9805** The usual case is that sqlite3_serialize() copies the serialization of 9806** the database into memory obtained from [sqlite3_malloc64()] and returns 9807** a pointer to that memory. The caller is responsible for freeing the 9808** returned value to avoid a memory leak. However, if the F argument 9809** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 9810** are made, and the sqlite3_serialize() function will return a pointer 9811** to the contiguous memory representation of the database that SQLite 9812** is currently using for that database, or NULL if the no such contiguous 9813** memory representation of the database exists. A contiguous memory 9814** representation of the database will usually only exist if there has 9815** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 9816** values of D and S. 9817** The size of the database is written into *P even if the 9818** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy 9819** of the database exists. 9820** 9821** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 9822** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 9823** allocation error occurs. 9824** 9825** This interface is omitted if SQLite is compiled with the 9826** [SQLITE_OMIT_DESERIALIZE] option. 9827*/ 9828unsigned char *sqlite3_serialize( 9829 sqlite3 *db, /* The database connection */ 9830 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 9831 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 9832 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 9833); 9834 9835/* 9836** CAPI3REF: Flags for sqlite3_serialize 9837** 9838** Zero or more of the following constants can be OR-ed together for 9839** the F argument to [sqlite3_serialize(D,S,P,F)]. 9840** 9841** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 9842** a pointer to contiguous in-memory database that it is currently using, 9843** without making a copy of the database. If SQLite is not currently using 9844** a contiguous in-memory database, then this option causes 9845** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 9846** using a contiguous in-memory database if it has been initialized by a 9847** prior call to [sqlite3_deserialize()]. 9848*/ 9849#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 9850 9851/* 9852** CAPI3REF: Deserialize a database 9853** 9854** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 9855** [database connection] D to disconnect from database S and then 9856** reopen S as an in-memory database based on the serialization contained 9857** in P. The serialized database P is N bytes in size. M is the size of 9858** the buffer P, which might be larger than N. If M is larger than N, and 9859** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 9860** permitted to add content to the in-memory database as long as the total 9861** size does not exceed M bytes. 9862** 9863** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 9864** invoke sqlite3_free() on the serialization buffer when the database 9865** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 9866** SQLite will try to increase the buffer size using sqlite3_realloc64() 9867** if writes on the database cause it to grow larger than M bytes. 9868** 9869** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 9870** database is currently in a read transaction or is involved in a backup 9871** operation. 9872** 9873** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 9874** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 9875** [sqlite3_free()] is invoked on argument P prior to returning. 9876** 9877** This interface is omitted if SQLite is compiled with the 9878** [SQLITE_OMIT_DESERIALIZE] option. 9879*/ 9880int sqlite3_deserialize( 9881 sqlite3 *db, /* The database connection */ 9882 const char *zSchema, /* Which DB to reopen with the deserialization */ 9883 unsigned char *pData, /* The serialized database content */ 9884 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 9885 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 9886 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 9887); 9888 9889/* 9890** CAPI3REF: Flags for sqlite3_deserialize() 9891** 9892** The following are allowed values for 6th argument (the F argument) to 9893** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 9894** 9895** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 9896** in the P argument is held in memory obtained from [sqlite3_malloc64()] 9897** and that SQLite should take ownership of this memory and automatically 9898** free it when it has finished using it. Without this flag, the caller 9899** is responsible for freeing any dynamically allocated memory. 9900** 9901** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 9902** grow the size of the database using calls to [sqlite3_realloc64()]. This 9903** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 9904** Without this flag, the deserialized database cannot increase in size beyond 9905** the number of bytes specified by the M parameter. 9906** 9907** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 9908** should be treated as read-only. 9909*/ 9910#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 9911#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 9912#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 9913 9914/* 9915** Undo the hack that converts floating point types to integer for 9916** builds on processors without floating point support. 9917*/ 9918#ifdef SQLITE_OMIT_FLOATING_POINT 9919# undef double 9920#endif 9921 9922#ifdef __cplusplus 9923} /* End of the 'extern "C"' block */ 9924#endif 9925#endif /* SQLITE3_H */ 9926