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#define SQLITE_FCNTL_LOCKSTATE 1 1133#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1134#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1135#define SQLITE_FCNTL_LAST_ERRNO 4 1136#define SQLITE_FCNTL_SIZE_HINT 5 1137#define SQLITE_FCNTL_CHUNK_SIZE 6 1138#define SQLITE_FCNTL_FILE_POINTER 7 1139#define SQLITE_FCNTL_SYNC_OMITTED 8 1140#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1141#define SQLITE_FCNTL_PERSIST_WAL 10 1142#define SQLITE_FCNTL_OVERWRITE 11 1143#define SQLITE_FCNTL_VFSNAME 12 1144#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1145#define SQLITE_FCNTL_PRAGMA 14 1146#define SQLITE_FCNTL_BUSYHANDLER 15 1147#define SQLITE_FCNTL_TEMPFILENAME 16 1148#define SQLITE_FCNTL_MMAP_SIZE 18 1149#define SQLITE_FCNTL_TRACE 19 1150#define SQLITE_FCNTL_HAS_MOVED 20 1151#define SQLITE_FCNTL_SYNC 21 1152#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1153#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1154#define SQLITE_FCNTL_WAL_BLOCK 24 1155#define SQLITE_FCNTL_ZIPVFS 25 1156#define SQLITE_FCNTL_RBU 26 1157#define SQLITE_FCNTL_VFS_POINTER 27 1158#define SQLITE_FCNTL_JOURNAL_POINTER 28 1159#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1160#define SQLITE_FCNTL_PDB 30 1161#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1162#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1163#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1164#define SQLITE_FCNTL_LOCK_TIMEOUT 34 1165#define SQLITE_FCNTL_DATA_VERSION 35 1166#define SQLITE_FCNTL_SIZE_LIMIT 36 1167#define SQLITE_FCNTL_CKPT_DONE 37 1168#define SQLITE_FCNTL_RESERVE_BYTES 38 1169#define SQLITE_FCNTL_CKPT_START 39 1170 1171/* deprecated names */ 1172#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1173#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1174#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1175 1176 1177/* 1178** CAPI3REF: Mutex Handle 1179** 1180** The mutex module within SQLite defines [sqlite3_mutex] to be an 1181** abstract type for a mutex object. The SQLite core never looks 1182** at the internal representation of an [sqlite3_mutex]. It only 1183** deals with pointers to the [sqlite3_mutex] object. 1184** 1185** Mutexes are created using [sqlite3_mutex_alloc()]. 1186*/ 1187typedef struct sqlite3_mutex sqlite3_mutex; 1188 1189/* 1190** CAPI3REF: Loadable Extension Thunk 1191** 1192** A pointer to the opaque sqlite3_api_routines structure is passed as 1193** the third parameter to entry points of [loadable extensions]. This 1194** structure must be typedefed in order to work around compiler warnings 1195** on some platforms. 1196*/ 1197typedef struct sqlite3_api_routines sqlite3_api_routines; 1198 1199/* 1200** CAPI3REF: OS Interface Object 1201** 1202** An instance of the sqlite3_vfs object defines the interface between 1203** the SQLite core and the underlying operating system. The "vfs" 1204** in the name of the object stands for "virtual file system". See 1205** the [VFS | VFS documentation] for further information. 1206** 1207** The VFS interface is sometimes extended by adding new methods onto 1208** the end. Each time such an extension occurs, the iVersion field 1209** is incremented. The iVersion value started out as 1 in 1210** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1211** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1212** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1213** may be appended to the sqlite3_vfs object and the iVersion value 1214** may increase again in future versions of SQLite. 1215** Note that due to an oversight, the structure 1216** of the sqlite3_vfs object changed in the transition from 1217** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1218** and yet the iVersion field was not increased. 1219** 1220** The szOsFile field is the size of the subclassed [sqlite3_file] 1221** structure used by this VFS. mxPathname is the maximum length of 1222** a pathname in this VFS. 1223** 1224** Registered sqlite3_vfs objects are kept on a linked list formed by 1225** the pNext pointer. The [sqlite3_vfs_register()] 1226** and [sqlite3_vfs_unregister()] interfaces manage this list 1227** in a thread-safe way. The [sqlite3_vfs_find()] interface 1228** searches the list. Neither the application code nor the VFS 1229** implementation should use the pNext pointer. 1230** 1231** The pNext field is the only field in the sqlite3_vfs 1232** structure that SQLite will ever modify. SQLite will only access 1233** or modify this field while holding a particular static mutex. 1234** The application should never modify anything within the sqlite3_vfs 1235** object once the object has been registered. 1236** 1237** The zName field holds the name of the VFS module. The name must 1238** be unique across all VFS modules. 1239** 1240** [[sqlite3_vfs.xOpen]] 1241** ^SQLite guarantees that the zFilename parameter to xOpen 1242** is either a NULL pointer or string obtained 1243** from xFullPathname() with an optional suffix added. 1244** ^If a suffix is added to the zFilename parameter, it will 1245** consist of a single "-" character followed by no more than 1246** 11 alphanumeric and/or "-" characters. 1247** ^SQLite further guarantees that 1248** the string will be valid and unchanged until xClose() is 1249** called. Because of the previous sentence, 1250** the [sqlite3_file] can safely store a pointer to the 1251** filename if it needs to remember the filename for some reason. 1252** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1253** must invent its own temporary name for the file. ^Whenever the 1254** xFilename parameter is NULL it will also be the case that the 1255** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1256** 1257** The flags argument to xOpen() includes all bits set in 1258** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1259** or [sqlite3_open16()] is used, then flags includes at least 1260** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1261** If xOpen() opens a file read-only then it sets *pOutFlags to 1262** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1263** 1264** ^(SQLite will also add one of the following flags to the xOpen() 1265** call, depending on the object being opened: 1266** 1267** <ul> 1268** <li> [SQLITE_OPEN_MAIN_DB] 1269** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1270** <li> [SQLITE_OPEN_TEMP_DB] 1271** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1272** <li> [SQLITE_OPEN_TRANSIENT_DB] 1273** <li> [SQLITE_OPEN_SUBJOURNAL] 1274** <li> [SQLITE_OPEN_SUPER_JOURNAL] 1275** <li> [SQLITE_OPEN_WAL] 1276** </ul>)^ 1277** 1278** The file I/O implementation can use the object type flags to 1279** change the way it deals with files. For example, an application 1280** that does not care about crash recovery or rollback might make 1281** the open of a journal file a no-op. Writes to this journal would 1282** also be no-ops, and any attempt to read the journal would return 1283** SQLITE_IOERR. Or the implementation might recognize that a database 1284** file will be doing page-aligned sector reads and writes in a random 1285** order and set up its I/O subsystem accordingly. 1286** 1287** SQLite might also add one of the following flags to the xOpen method: 1288** 1289** <ul> 1290** <li> [SQLITE_OPEN_DELETEONCLOSE] 1291** <li> [SQLITE_OPEN_EXCLUSIVE] 1292** </ul> 1293** 1294** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1295** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1296** will be set for TEMP databases and their journals, transient 1297** databases, and subjournals. 1298** 1299** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1300** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1301** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1302** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1303** SQLITE_OPEN_CREATE, is used to indicate that file should always 1304** be created, and that it is an error if it already exists. 1305** It is <i>not</i> used to indicate the file should be opened 1306** for exclusive access. 1307** 1308** ^At least szOsFile bytes of memory are allocated by SQLite 1309** to hold the [sqlite3_file] structure passed as the third 1310** argument to xOpen. The xOpen method does not have to 1311** allocate the structure; it should just fill it in. Note that 1312** the xOpen method must set the sqlite3_file.pMethods to either 1313** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1314** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1315** element will be valid after xOpen returns regardless of the success 1316** or failure of the xOpen call. 1317** 1318** [[sqlite3_vfs.xAccess]] 1319** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1320** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1321** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1322** to test whether a file is at least readable. The SQLITE_ACCESS_READ 1323** flag is never actually used and is not implemented in the built-in 1324** VFSes of SQLite. The file is named by the second argument and can be a 1325** directory. The xAccess method returns [SQLITE_OK] on success or some 1326** non-zero error code if there is an I/O error or if the name of 1327** the file given in the second argument is illegal. If SQLITE_OK 1328** is returned, then non-zero or zero is written into *pResOut to indicate 1329** whether or not the file is accessible. 1330** 1331** ^SQLite will always allocate at least mxPathname+1 bytes for the 1332** output buffer xFullPathname. The exact size of the output buffer 1333** is also passed as a parameter to both methods. If the output buffer 1334** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1335** handled as a fatal error by SQLite, vfs implementations should endeavor 1336** to prevent this by setting mxPathname to a sufficiently large value. 1337** 1338** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1339** interfaces are not strictly a part of the filesystem, but they are 1340** included in the VFS structure for completeness. 1341** The xRandomness() function attempts to return nBytes bytes 1342** of good-quality randomness into zOut. The return value is 1343** the actual number of bytes of randomness obtained. 1344** The xSleep() method causes the calling thread to sleep for at 1345** least the number of microseconds given. ^The xCurrentTime() 1346** method returns a Julian Day Number for the current date and time as 1347** a floating point value. 1348** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1349** Day Number multiplied by 86400000 (the number of milliseconds in 1350** a 24-hour day). 1351** ^SQLite will use the xCurrentTimeInt64() method to get the current 1352** date and time if that method is available (if iVersion is 2 or 1353** greater and the function pointer is not NULL) and will fall back 1354** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1355** 1356** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1357** are not used by the SQLite core. These optional interfaces are provided 1358** by some VFSes to facilitate testing of the VFS code. By overriding 1359** system calls with functions under its control, a test program can 1360** simulate faults and error conditions that would otherwise be difficult 1361** or impossible to induce. The set of system calls that can be overridden 1362** varies from one VFS to another, and from one version of the same VFS to the 1363** next. Applications that use these interfaces must be prepared for any 1364** or all of these interfaces to be NULL or for their behavior to change 1365** from one release to the next. Applications must not attempt to access 1366** any of these methods if the iVersion of the VFS is less than 3. 1367*/ 1368typedef struct sqlite3_vfs sqlite3_vfs; 1369typedef void (*sqlite3_syscall_ptr)(void); 1370struct sqlite3_vfs { 1371 int iVersion; /* Structure version number (currently 3) */ 1372 int szOsFile; /* Size of subclassed sqlite3_file */ 1373 int mxPathname; /* Maximum file pathname length */ 1374 sqlite3_vfs *pNext; /* Next registered VFS */ 1375 const char *zName; /* Name of this virtual file system */ 1376 void *pAppData; /* Pointer to application-specific data */ 1377 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1378 int flags, int *pOutFlags); 1379 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1380 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1381 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1382 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1383 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1384 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1385 void (*xDlClose)(sqlite3_vfs*, void*); 1386 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1387 int (*xSleep)(sqlite3_vfs*, int microseconds); 1388 int (*xCurrentTime)(sqlite3_vfs*, double*); 1389 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1390 /* 1391 ** The methods above are in version 1 of the sqlite_vfs object 1392 ** definition. Those that follow are added in version 2 or later 1393 */ 1394 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1395 /* 1396 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1397 ** Those below are for version 3 and greater. 1398 */ 1399 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1400 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1401 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1402 /* 1403 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1404 ** New fields may be appended in future versions. The iVersion 1405 ** value will increment whenever this happens. 1406 */ 1407}; 1408 1409/* 1410** CAPI3REF: Flags for the xAccess VFS method 1411** 1412** These integer constants can be used as the third parameter to 1413** the xAccess method of an [sqlite3_vfs] object. They determine 1414** what kind of permissions the xAccess method is looking for. 1415** With SQLITE_ACCESS_EXISTS, the xAccess method 1416** simply checks whether the file exists. 1417** With SQLITE_ACCESS_READWRITE, the xAccess method 1418** checks whether the named directory is both readable and writable 1419** (in other words, if files can be added, removed, and renamed within 1420** the directory). 1421** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1422** [temp_store_directory pragma], though this could change in a future 1423** release of SQLite. 1424** With SQLITE_ACCESS_READ, the xAccess method 1425** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1426** currently unused, though it might be used in a future release of 1427** SQLite. 1428*/ 1429#define SQLITE_ACCESS_EXISTS 0 1430#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1431#define SQLITE_ACCESS_READ 2 /* Unused */ 1432 1433/* 1434** CAPI3REF: Flags for the xShmLock VFS method 1435** 1436** These integer constants define the various locking operations 1437** allowed by the xShmLock method of [sqlite3_io_methods]. The 1438** following are the only legal combinations of flags to the 1439** xShmLock method: 1440** 1441** <ul> 1442** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1443** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1444** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1445** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1446** </ul> 1447** 1448** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1449** was given on the corresponding lock. 1450** 1451** The xShmLock method can transition between unlocked and SHARED or 1452** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1453** and EXCLUSIVE. 1454*/ 1455#define SQLITE_SHM_UNLOCK 1 1456#define SQLITE_SHM_LOCK 2 1457#define SQLITE_SHM_SHARED 4 1458#define SQLITE_SHM_EXCLUSIVE 8 1459 1460/* 1461** CAPI3REF: Maximum xShmLock index 1462** 1463** The xShmLock method on [sqlite3_io_methods] may use values 1464** between 0 and this upper bound as its "offset" argument. 1465** The SQLite core will never attempt to acquire or release a 1466** lock outside of this range 1467*/ 1468#define SQLITE_SHM_NLOCK 8 1469 1470 1471/* 1472** CAPI3REF: Initialize The SQLite Library 1473** 1474** ^The sqlite3_initialize() routine initializes the 1475** SQLite library. ^The sqlite3_shutdown() routine 1476** deallocates any resources that were allocated by sqlite3_initialize(). 1477** These routines are designed to aid in process initialization and 1478** shutdown on embedded systems. Workstation applications using 1479** SQLite normally do not need to invoke either of these routines. 1480** 1481** A call to sqlite3_initialize() is an "effective" call if it is 1482** the first time sqlite3_initialize() is invoked during the lifetime of 1483** the process, or if it is the first time sqlite3_initialize() is invoked 1484** following a call to sqlite3_shutdown(). ^(Only an effective call 1485** of sqlite3_initialize() does any initialization. All other calls 1486** are harmless no-ops.)^ 1487** 1488** A call to sqlite3_shutdown() is an "effective" call if it is the first 1489** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1490** an effective call to sqlite3_shutdown() does any deinitialization. 1491** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1492** 1493** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1494** is not. The sqlite3_shutdown() interface must only be called from a 1495** single thread. All open [database connections] must be closed and all 1496** other SQLite resources must be deallocated prior to invoking 1497** sqlite3_shutdown(). 1498** 1499** Among other things, ^sqlite3_initialize() will invoke 1500** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1501** will invoke sqlite3_os_end(). 1502** 1503** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1504** ^If for some reason, sqlite3_initialize() is unable to initialize 1505** the library (perhaps it is unable to allocate a needed resource such 1506** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1507** 1508** ^The sqlite3_initialize() routine is called internally by many other 1509** SQLite interfaces so that an application usually does not need to 1510** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1511** calls sqlite3_initialize() so the SQLite library will be automatically 1512** initialized when [sqlite3_open()] is called if it has not be initialized 1513** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1514** compile-time option, then the automatic calls to sqlite3_initialize() 1515** are omitted and the application must call sqlite3_initialize() directly 1516** prior to using any other SQLite interface. For maximum portability, 1517** it is recommended that applications always invoke sqlite3_initialize() 1518** directly prior to using any other SQLite interface. Future releases 1519** of SQLite may require this. In other words, the behavior exhibited 1520** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1521** default behavior in some future release of SQLite. 1522** 1523** The sqlite3_os_init() routine does operating-system specific 1524** initialization of the SQLite library. The sqlite3_os_end() 1525** routine undoes the effect of sqlite3_os_init(). Typical tasks 1526** performed by these routines include allocation or deallocation 1527** of static resources, initialization of global variables, 1528** setting up a default [sqlite3_vfs] module, or setting up 1529** a default configuration using [sqlite3_config()]. 1530** 1531** The application should never invoke either sqlite3_os_init() 1532** or sqlite3_os_end() directly. The application should only invoke 1533** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1534** interface is called automatically by sqlite3_initialize() and 1535** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1536** implementations for sqlite3_os_init() and sqlite3_os_end() 1537** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1538** When [custom builds | built for other platforms] 1539** (using the [SQLITE_OS_OTHER=1] compile-time 1540** option) the application must supply a suitable implementation for 1541** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1542** implementation of sqlite3_os_init() or sqlite3_os_end() 1543** must return [SQLITE_OK] on success and some other [error code] upon 1544** failure. 1545*/ 1546int sqlite3_initialize(void); 1547int sqlite3_shutdown(void); 1548int sqlite3_os_init(void); 1549int sqlite3_os_end(void); 1550 1551/* 1552** CAPI3REF: Configuring The SQLite Library 1553** 1554** The sqlite3_config() interface is used to make global configuration 1555** changes to SQLite in order to tune SQLite to the specific needs of 1556** the application. The default configuration is recommended for most 1557** applications and so this routine is usually not necessary. It is 1558** provided to support rare applications with unusual needs. 1559** 1560** <b>The sqlite3_config() interface is not threadsafe. The application 1561** must ensure that no other SQLite interfaces are invoked by other 1562** threads while sqlite3_config() is running.</b> 1563** 1564** The sqlite3_config() interface 1565** may only be invoked prior to library initialization using 1566** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1567** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1568** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1569** Note, however, that ^sqlite3_config() can be called as part of the 1570** implementation of an application-defined [sqlite3_os_init()]. 1571** 1572** The first argument to sqlite3_config() is an integer 1573** [configuration option] that determines 1574** what property of SQLite is to be configured. Subsequent arguments 1575** vary depending on the [configuration option] 1576** in the first argument. 1577** 1578** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1579** ^If the option is unknown or SQLite is unable to set the option 1580** then this routine returns a non-zero [error code]. 1581*/ 1582int sqlite3_config(int, ...); 1583 1584/* 1585** CAPI3REF: Configure database connections 1586** METHOD: sqlite3 1587** 1588** The sqlite3_db_config() interface is used to make configuration 1589** changes to a [database connection]. The interface is similar to 1590** [sqlite3_config()] except that the changes apply to a single 1591** [database connection] (specified in the first argument). 1592** 1593** The second argument to sqlite3_db_config(D,V,...) is the 1594** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1595** that indicates what aspect of the [database connection] is being configured. 1596** Subsequent arguments vary depending on the configuration verb. 1597** 1598** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1599** the call is considered successful. 1600*/ 1601int sqlite3_db_config(sqlite3*, int op, ...); 1602 1603/* 1604** CAPI3REF: Memory Allocation Routines 1605** 1606** An instance of this object defines the interface between SQLite 1607** and low-level memory allocation routines. 1608** 1609** This object is used in only one place in the SQLite interface. 1610** A pointer to an instance of this object is the argument to 1611** [sqlite3_config()] when the configuration option is 1612** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1613** By creating an instance of this object 1614** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1615** during configuration, an application can specify an alternative 1616** memory allocation subsystem for SQLite to use for all of its 1617** dynamic memory needs. 1618** 1619** Note that SQLite comes with several [built-in memory allocators] 1620** that are perfectly adequate for the overwhelming majority of applications 1621** and that this object is only useful to a tiny minority of applications 1622** with specialized memory allocation requirements. This object is 1623** also used during testing of SQLite in order to specify an alternative 1624** memory allocator that simulates memory out-of-memory conditions in 1625** order to verify that SQLite recovers gracefully from such 1626** conditions. 1627** 1628** The xMalloc, xRealloc, and xFree methods must work like the 1629** malloc(), realloc() and free() functions from the standard C library. 1630** ^SQLite guarantees that the second argument to 1631** xRealloc is always a value returned by a prior call to xRoundup. 1632** 1633** xSize should return the allocated size of a memory allocation 1634** previously obtained from xMalloc or xRealloc. The allocated size 1635** is always at least as big as the requested size but may be larger. 1636** 1637** The xRoundup method returns what would be the allocated size of 1638** a memory allocation given a particular requested size. Most memory 1639** allocators round up memory allocations at least to the next multiple 1640** of 8. Some allocators round up to a larger multiple or to a power of 2. 1641** Every memory allocation request coming in through [sqlite3_malloc()] 1642** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1643** that causes the corresponding memory allocation to fail. 1644** 1645** The xInit method initializes the memory allocator. For example, 1646** it might allocate any required mutexes or initialize internal data 1647** structures. The xShutdown method is invoked (indirectly) by 1648** [sqlite3_shutdown()] and should deallocate any resources acquired 1649** by xInit. The pAppData pointer is used as the only parameter to 1650** xInit and xShutdown. 1651** 1652** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes 1653** the xInit method, so the xInit method need not be threadsafe. The 1654** xShutdown method is only called from [sqlite3_shutdown()] so it does 1655** not need to be threadsafe either. For all other methods, SQLite 1656** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1657** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1658** it is by default) and so the methods are automatically serialized. 1659** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1660** methods must be threadsafe or else make their own arrangements for 1661** serialization. 1662** 1663** SQLite will never invoke xInit() more than once without an intervening 1664** call to xShutdown(). 1665*/ 1666typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1667struct sqlite3_mem_methods { 1668 void *(*xMalloc)(int); /* Memory allocation function */ 1669 void (*xFree)(void*); /* Free a prior allocation */ 1670 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1671 int (*xSize)(void*); /* Return the size of an allocation */ 1672 int (*xRoundup)(int); /* Round up request size to allocation size */ 1673 int (*xInit)(void*); /* Initialize the memory allocator */ 1674 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1675 void *pAppData; /* Argument to xInit() and xShutdown() */ 1676}; 1677 1678/* 1679** CAPI3REF: Configuration Options 1680** KEYWORDS: {configuration option} 1681** 1682** These constants are the available integer configuration options that 1683** can be passed as the first argument to the [sqlite3_config()] interface. 1684** 1685** New configuration options may be added in future releases of SQLite. 1686** Existing configuration options might be discontinued. Applications 1687** should check the return code from [sqlite3_config()] to make sure that 1688** the call worked. The [sqlite3_config()] interface will return a 1689** non-zero [error code] if a discontinued or unsupported configuration option 1690** is invoked. 1691** 1692** <dl> 1693** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1694** <dd>There are no arguments to this option. ^This option sets the 1695** [threading mode] to Single-thread. In other words, it disables 1696** all mutexing and puts SQLite into a mode where it can only be used 1697** by a single thread. ^If SQLite is compiled with 1698** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1699** it is not possible to change the [threading mode] from its default 1700** value of Single-thread and so [sqlite3_config()] will return 1701** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1702** configuration option.</dd> 1703** 1704** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1705** <dd>There are no arguments to this option. ^This option sets the 1706** [threading mode] to Multi-thread. In other words, it disables 1707** mutexing on [database connection] and [prepared statement] objects. 1708** The application is responsible for serializing access to 1709** [database connections] and [prepared statements]. But other mutexes 1710** are enabled so that SQLite will be safe to use in a multi-threaded 1711** environment as long as no two threads attempt to use the same 1712** [database connection] at the same time. ^If SQLite is compiled with 1713** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1714** it is not possible to set the Multi-thread [threading mode] and 1715** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1716** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1717** 1718** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1719** <dd>There are no arguments to this option. ^This option sets the 1720** [threading mode] to Serialized. In other words, this option enables 1721** all mutexes including the recursive 1722** mutexes on [database connection] and [prepared statement] objects. 1723** In this mode (which is the default when SQLite is compiled with 1724** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1725** to [database connections] and [prepared statements] so that the 1726** application is free to use the same [database connection] or the 1727** same [prepared statement] in different threads at the same time. 1728** ^If SQLite is compiled with 1729** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1730** it is not possible to set the Serialized [threading mode] and 1731** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1732** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1733** 1734** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1735** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1736** a pointer to an instance of the [sqlite3_mem_methods] structure. 1737** The argument specifies 1738** alternative low-level memory allocation routines to be used in place of 1739** the memory allocation routines built into SQLite.)^ ^SQLite makes 1740** its own private copy of the content of the [sqlite3_mem_methods] structure 1741** before the [sqlite3_config()] call returns.</dd> 1742** 1743** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1744** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1745** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1746** The [sqlite3_mem_methods] 1747** structure is filled with the currently defined memory allocation routines.)^ 1748** This option can be used to overload the default memory allocation 1749** routines with a wrapper that simulations memory allocation failure or 1750** tracks memory usage, for example. </dd> 1751** 1752** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1753** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1754** type int, interpreted as a boolean, which if true provides a hint to 1755** SQLite that it should avoid large memory allocations if possible. 1756** SQLite will run faster if it is free to make large memory allocations, 1757** but some application might prefer to run slower in exchange for 1758** guarantees about memory fragmentation that are possible if large 1759** allocations are avoided. This hint is normally off. 1760** </dd> 1761** 1762** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1763** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1764** interpreted as a boolean, which enables or disables the collection of 1765** memory allocation statistics. ^(When memory allocation statistics are 1766** disabled, the following SQLite interfaces become non-operational: 1767** <ul> 1768** <li> [sqlite3_hard_heap_limit64()] 1769** <li> [sqlite3_memory_used()] 1770** <li> [sqlite3_memory_highwater()] 1771** <li> [sqlite3_soft_heap_limit64()] 1772** <li> [sqlite3_status64()] 1773** </ul>)^ 1774** ^Memory allocation statistics are enabled by default unless SQLite is 1775** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1776** allocation statistics are disabled by default. 1777** </dd> 1778** 1779** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1780** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1781** </dd> 1782** 1783** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1784** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1785** that SQLite can use for the database page cache with the default page 1786** cache implementation. 1787** This configuration option is a no-op if an application-defined page 1788** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1789** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1790** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1791** and the number of cache lines (N). 1792** The sz argument should be the size of the largest database page 1793** (a power of two between 512 and 65536) plus some extra bytes for each 1794** page header. ^The number of extra bytes needed by the page header 1795** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1796** ^It is harmless, apart from the wasted memory, 1797** for the sz parameter to be larger than necessary. The pMem 1798** argument must be either a NULL pointer or a pointer to an 8-byte 1799** aligned block of memory of at least sz*N bytes, otherwise 1800** subsequent behavior is undefined. 1801** ^When pMem is not NULL, SQLite will strive to use the memory provided 1802** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1803** a page cache line is larger than sz bytes or if all of the pMem buffer 1804** is exhausted. 1805** ^If pMem is NULL and N is non-zero, then each database connection 1806** does an initial bulk allocation for page cache memory 1807** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1808** of -1024*N bytes if N is negative, . ^If additional 1809** page cache memory is needed beyond what is provided by the initial 1810** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1811** additional cache line. </dd> 1812** 1813** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1814** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1815** that SQLite will use for all of its dynamic memory allocation needs 1816** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1817** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1818** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1819** [SQLITE_ERROR] if invoked otherwise. 1820** ^There are three arguments to SQLITE_CONFIG_HEAP: 1821** An 8-byte aligned pointer to the memory, 1822** the number of bytes in the memory buffer, and the minimum allocation size. 1823** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1824** to using its default memory allocator (the system malloc() implementation), 1825** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1826** memory pointer is not NULL then the alternative memory 1827** allocator is engaged to handle all of SQLites memory allocation needs. 1828** The first pointer (the memory pointer) must be aligned to an 8-byte 1829** boundary or subsequent behavior of SQLite will be undefined. 1830** The minimum allocation size is capped at 2**12. Reasonable values 1831** for the minimum allocation size are 2**5 through 2**8.</dd> 1832** 1833** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1834** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1835** pointer to an instance of the [sqlite3_mutex_methods] structure. 1836** The argument specifies alternative low-level mutex routines to be used 1837** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1838** the content of the [sqlite3_mutex_methods] structure before the call to 1839** [sqlite3_config()] returns. ^If SQLite is compiled with 1840** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1841** the entire mutexing subsystem is omitted from the build and hence calls to 1842** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1843** return [SQLITE_ERROR].</dd> 1844** 1845** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1846** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1847** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1848** [sqlite3_mutex_methods] 1849** structure is filled with the currently defined mutex routines.)^ 1850** This option can be used to overload the default mutex allocation 1851** routines with a wrapper used to track mutex usage for performance 1852** profiling or testing, for example. ^If SQLite is compiled with 1853** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1854** the entire mutexing subsystem is omitted from the build and hence calls to 1855** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1856** return [SQLITE_ERROR].</dd> 1857** 1858** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1859** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1860** the default size of lookaside memory on each [database connection]. 1861** The first argument is the 1862** size of each lookaside buffer slot and the second is the number of 1863** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1864** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1865** option to [sqlite3_db_config()] can be used to change the lookaside 1866** configuration on individual connections.)^ </dd> 1867** 1868** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1869** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1870** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1871** the interface to a custom page cache implementation.)^ 1872** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1873** 1874** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1875** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1876** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1877** the current page cache implementation into that object.)^ </dd> 1878** 1879** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1880** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1881** global [error log]. 1882** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1883** function with a call signature of void(*)(void*,int,const char*), 1884** and a pointer to void. ^If the function pointer is not NULL, it is 1885** invoked by [sqlite3_log()] to process each logging event. ^If the 1886** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1887** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1888** passed through as the first parameter to the application-defined logger 1889** function whenever that function is invoked. ^The second parameter to 1890** the logger function is a copy of the first parameter to the corresponding 1891** [sqlite3_log()] call and is intended to be a [result code] or an 1892** [extended result code]. ^The third parameter passed to the logger is 1893** log message after formatting via [sqlite3_snprintf()]. 1894** The SQLite logging interface is not reentrant; the logger function 1895** supplied by the application must not invoke any SQLite interface. 1896** In a multi-threaded application, the application-defined logger 1897** function must be threadsafe. </dd> 1898** 1899** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1900** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1901** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1902** then URI handling is globally disabled.)^ ^If URI handling is globally 1903** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1904** [sqlite3_open16()] or 1905** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1906** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1907** connection is opened. ^If it is globally disabled, filenames are 1908** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1909** database connection is opened. ^(By default, URI handling is globally 1910** disabled. The default value may be changed by compiling with the 1911** [SQLITE_USE_URI] symbol defined.)^ 1912** 1913** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1914** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1915** argument which is interpreted as a boolean in order to enable or disable 1916** the use of covering indices for full table scans in the query optimizer. 1917** ^The default setting is determined 1918** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1919** if that compile-time option is omitted. 1920** The ability to disable the use of covering indices for full table scans 1921** is because some incorrectly coded legacy applications might malfunction 1922** when the optimization is enabled. Providing the ability to 1923** disable the optimization allows the older, buggy application code to work 1924** without change even with newer versions of SQLite. 1925** 1926** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1927** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1928** <dd> These options are obsolete and should not be used by new code. 1929** They are retained for backwards compatibility but are now no-ops. 1930** </dd> 1931** 1932** [[SQLITE_CONFIG_SQLLOG]] 1933** <dt>SQLITE_CONFIG_SQLLOG 1934** <dd>This option is only available if sqlite is compiled with the 1935** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1936** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1937** The second should be of type (void*). The callback is invoked by the library 1938** in three separate circumstances, identified by the value passed as the 1939** fourth parameter. If the fourth parameter is 0, then the database connection 1940** passed as the second argument has just been opened. The third argument 1941** points to a buffer containing the name of the main database file. If the 1942** fourth parameter is 1, then the SQL statement that the third parameter 1943** points to has just been executed. Or, if the fourth parameter is 2, then 1944** the connection being passed as the second parameter is being closed. The 1945** third parameter is passed NULL In this case. An example of using this 1946** configuration option can be seen in the "test_sqllog.c" source file in 1947** the canonical SQLite source tree.</dd> 1948** 1949** [[SQLITE_CONFIG_MMAP_SIZE]] 1950** <dt>SQLITE_CONFIG_MMAP_SIZE 1951** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1952** that are the default mmap size limit (the default setting for 1953** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1954** ^The default setting can be overridden by each database connection using 1955** either the [PRAGMA mmap_size] command, or by using the 1956** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1957** will be silently truncated if necessary so that it does not exceed the 1958** compile-time maximum mmap size set by the 1959** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1960** ^If either argument to this option is negative, then that argument is 1961** changed to its compile-time default. 1962** 1963** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1964** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1965** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1966** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1967** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1968** that specifies the maximum size of the created heap. 1969** 1970** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1971** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1972** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1973** is a pointer to an integer and writes into that integer the number of extra 1974** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1975** The amount of extra space required can change depending on the compiler, 1976** target platform, and SQLite version. 1977** 1978** [[SQLITE_CONFIG_PMASZ]] 1979** <dt>SQLITE_CONFIG_PMASZ 1980** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1981** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1982** sorter to that integer. The default minimum PMA Size is set by the 1983** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1984** to help with sort operations when multithreaded sorting 1985** is enabled (using the [PRAGMA threads] command) and the amount of content 1986** to be sorted exceeds the page size times the minimum of the 1987** [PRAGMA cache_size] setting and this value. 1988** 1989** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1990** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1991** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1992** becomes the [statement journal] spill-to-disk threshold. 1993** [Statement journals] are held in memory until their size (in bytes) 1994** exceeds this threshold, at which point they are written to disk. 1995** Or if the threshold is -1, statement journals are always held 1996** exclusively in memory. 1997** Since many statement journals never become large, setting the spill 1998** threshold to a value such as 64KiB can greatly reduce the amount of 1999** I/O required to support statement rollback. 2000** The default value for this setting is controlled by the 2001** [SQLITE_STMTJRNL_SPILL] compile-time option. 2002** 2003** [[SQLITE_CONFIG_SORTERREF_SIZE]] 2004** <dt>SQLITE_CONFIG_SORTERREF_SIZE 2005** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter 2006** of type (int) - the new value of the sorter-reference size threshold. 2007** Usually, when SQLite uses an external sort to order records according 2008** to an ORDER BY clause, all fields required by the caller are present in the 2009** sorted records. However, if SQLite determines based on the declared type 2010** of a table column that its values are likely to be very large - larger 2011** than the configured sorter-reference size threshold - then a reference 2012** is stored in each sorted record and the required column values loaded 2013** from the database as records are returned in sorted order. The default 2014** value for this option is to never use this optimization. Specifying a 2015** negative value for this option restores the default behaviour. 2016** This option is only available if SQLite is compiled with the 2017** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option. 2018** 2019** [[SQLITE_CONFIG_MEMDB_MAXSIZE]] 2020** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE 2021** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter 2022** [sqlite3_int64] parameter which is the default maximum size for an in-memory 2023** database created using [sqlite3_deserialize()]. This default maximum 2024** size can be adjusted up or down for individual databases using the 2025** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control]. If this 2026** configuration setting is never used, then the default maximum is determined 2027** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option. If that 2028** compile-time option is not set, then the default maximum is 1073741824. 2029** </dl> 2030*/ 2031#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 2032#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 2033#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 2034#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 2035#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 2036#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 2037#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 2038#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 2039#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 2040#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 2041#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 2042/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 2043#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 2044#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 2045#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 2046#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 2047#define SQLITE_CONFIG_URI 17 /* int */ 2048#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 2049#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 2050#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 2051#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 2052#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 2053#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 2054#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 2055#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 2056#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 2057#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 2058#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */ 2059#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */ 2060 2061/* 2062** CAPI3REF: Database Connection Configuration Options 2063** 2064** These constants are the available integer configuration options that 2065** can be passed as the second argument to the [sqlite3_db_config()] interface. 2066** 2067** New configuration options may be added in future releases of SQLite. 2068** Existing configuration options might be discontinued. Applications 2069** should check the return code from [sqlite3_db_config()] to make sure that 2070** the call worked. ^The [sqlite3_db_config()] interface will return a 2071** non-zero [error code] if a discontinued or unsupported configuration option 2072** is invoked. 2073** 2074** <dl> 2075** [[SQLITE_DBCONFIG_LOOKASIDE]] 2076** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 2077** <dd> ^This option takes three additional arguments that determine the 2078** [lookaside memory allocator] configuration for the [database connection]. 2079** ^The first argument (the third parameter to [sqlite3_db_config()] is a 2080** pointer to a memory buffer to use for lookaside memory. 2081** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 2082** may be NULL in which case SQLite will allocate the 2083** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 2084** size of each lookaside buffer slot. ^The third argument is the number of 2085** slots. The size of the buffer in the first argument must be greater than 2086** or equal to the product of the second and third arguments. The buffer 2087** must be aligned to an 8-byte boundary. ^If the second argument to 2088** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 2089** rounded down to the next smaller multiple of 8. ^(The lookaside memory 2090** configuration for a database connection can only be changed when that 2091** connection is not currently using lookaside memory, or in other words 2092** when the "current value" returned by 2093** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 2094** Any attempt to change the lookaside memory configuration when lookaside 2095** memory is in use leaves the configuration unchanged and returns 2096** [SQLITE_BUSY].)^</dd> 2097** 2098** [[SQLITE_DBCONFIG_ENABLE_FKEY]] 2099** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 2100** <dd> ^This option is used to enable or disable the enforcement of 2101** [foreign key constraints]. There should be two additional arguments. 2102** The first argument is an integer which is 0 to disable FK enforcement, 2103** positive to enable FK enforcement or negative to leave FK enforcement 2104** unchanged. The second parameter is a pointer to an integer into which 2105** is written 0 or 1 to indicate whether FK enforcement is off or on 2106** following this call. The second parameter may be a NULL pointer, in 2107** which case the FK enforcement setting is not reported back. </dd> 2108** 2109** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]] 2110** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2111** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2112** There should be two additional arguments. 2113** The first argument is an integer which is 0 to disable triggers, 2114** positive to enable triggers or negative to leave the setting unchanged. 2115** The second parameter is a pointer to an integer into which 2116** is written 0 or 1 to indicate whether triggers are disabled or enabled 2117** following this call. The second parameter may be a NULL pointer, in 2118** which case the trigger setting is not reported back. 2119** 2120** <p>Originally this option disabled all triggers. ^(However, since 2121** SQLite version 3.35.0, TEMP triggers are still allowed even if 2122** this option is off. So, in other words, this option now only disables 2123** triggers in the main database schema or in the schemas of ATTACH-ed 2124** databases.)^ </dd> 2125** 2126** [[SQLITE_DBCONFIG_ENABLE_VIEW]] 2127** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt> 2128** <dd> ^This option is used to enable or disable [CREATE VIEW | views]. 2129** There should be two additional arguments. 2130** The first argument is an integer which is 0 to disable views, 2131** positive to enable views or negative to leave the setting unchanged. 2132** The second parameter is a pointer to an integer into which 2133** is written 0 or 1 to indicate whether views are disabled or enabled 2134** following this call. The second parameter may be a NULL pointer, in 2135** which case the view setting is not reported back. </dd> 2136** 2137** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]] 2138** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2139** <dd> ^This option is used to enable or disable the 2140** [fts3_tokenizer()] function which is part of the 2141** [FTS3] full-text search engine extension. 2142** There should be two additional arguments. 2143** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2144** positive to enable fts3_tokenizer() or negative to leave the setting 2145** unchanged. 2146** The second parameter is a pointer to an integer into which 2147** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2148** following this call. The second parameter may be a NULL pointer, in 2149** which case the new setting is not reported back. </dd> 2150** 2151** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]] 2152** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2153** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2154** interface independently of the [load_extension()] SQL function. 2155** The [sqlite3_enable_load_extension()] API enables or disables both the 2156** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2157** There should be two additional arguments. 2158** When the first argument to this interface is 1, then only the C-API is 2159** enabled and the SQL function remains disabled. If the first argument to 2160** this interface is 0, then both the C-API and the SQL function are disabled. 2161** If the first argument is -1, then no changes are made to state of either the 2162** C-API or the SQL function. 2163** The second parameter is a pointer to an integer into which 2164** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2165** is disabled or enabled following this call. The second parameter may 2166** be a NULL pointer, in which case the new setting is not reported back. 2167** </dd> 2168** 2169** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2170** <dd> ^This option is used to change the name of the "main" database 2171** schema. ^The sole argument is a pointer to a constant UTF8 string 2172** which will become the new schema name in place of "main". ^SQLite 2173** does not make a copy of the new main schema name string, so the application 2174** must ensure that the argument passed into this DBCONFIG option is unchanged 2175** until after the database connection closes. 2176** </dd> 2177** 2178** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]] 2179** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2180** <dd> Usually, when a database in wal mode is closed or detached from a 2181** database handle, SQLite checks if this will mean that there are now no 2182** connections at all to the database. If so, it performs a checkpoint 2183** operation before closing the connection. This option may be used to 2184** override this behaviour. The first parameter passed to this operation 2185** is an integer - positive to disable checkpoints-on-close, or zero (the 2186** default) to enable them, and negative to leave the setting unchanged. 2187** The second parameter is a pointer to an integer 2188** into which is written 0 or 1 to indicate whether checkpoints-on-close 2189** have been disabled - 0 if they are not disabled, 1 if they are. 2190** </dd> 2191** 2192** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2193** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2194** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2195** a single SQL query statement will always use the same algorithm regardless 2196** of values of [bound parameters].)^ The QPSG disables some query optimizations 2197** that look at the values of bound parameters, which can make some queries 2198** slower. But the QPSG has the advantage of more predictable behavior. With 2199** the QPSG active, SQLite will always use the same query plan in the field as 2200** was used during testing in the lab. 2201** The first argument to this setting is an integer which is 0 to disable 2202** the QPSG, positive to enable QPSG, or negative to leave the setting 2203** unchanged. The second parameter is a pointer to an integer into which 2204** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2205** following this call. 2206** </dd> 2207** 2208** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2209** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2210** include output for any operations performed by trigger programs. This 2211** option is used to set or clear (the default) a flag that governs this 2212** behavior. The first parameter passed to this operation is an integer - 2213** positive to enable output for trigger programs, or zero to disable it, 2214** or negative to leave the setting unchanged. 2215** The second parameter is a pointer to an integer into which is written 2216** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2217** it is not disabled, 1 if it is. 2218** </dd> 2219** 2220** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt> 2221** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run 2222** [VACUUM] in order to reset a database back to an empty database 2223** with no schema and no content. The following process works even for 2224** a badly corrupted database file: 2225** <ol> 2226** <li> If the database connection is newly opened, make sure it has read the 2227** database schema by preparing then discarding some query against the 2228** database, or calling sqlite3_table_column_metadata(), ignoring any 2229** errors. This step is only necessary if the application desires to keep 2230** the database in WAL mode after the reset if it was in WAL mode before 2231** the reset. 2232** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0); 2233** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0); 2234** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0); 2235** </ol> 2236** Because resetting a database is destructive and irreversible, the 2237** process requires the use of this obscure API and multiple steps to help 2238** ensure that it does not happen by accident. 2239** 2240** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt> 2241** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the 2242** "defensive" flag for a database connection. When the defensive 2243** flag is enabled, language features that allow ordinary SQL to 2244** deliberately corrupt the database file are disabled. The disabled 2245** features include but are not limited to the following: 2246** <ul> 2247** <li> The [PRAGMA writable_schema=ON] statement. 2248** <li> The [PRAGMA journal_mode=OFF] statement. 2249** <li> Writes to the [sqlite_dbpage] virtual table. 2250** <li> Direct writes to [shadow tables]. 2251** </ul> 2252** </dd> 2253** 2254** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt> 2255** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the 2256** "writable_schema" flag. This has the same effect and is logically equivalent 2257** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF]. 2258** The first argument to this setting is an integer which is 0 to disable 2259** the writable_schema, positive to enable writable_schema, or negative to 2260** leave the setting unchanged. The second parameter is a pointer to an 2261** integer into which is written 0 or 1 to indicate whether the writable_schema 2262** is enabled or disabled following this call. 2263** </dd> 2264** 2265** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]] 2266** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt> 2267** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates 2268** the legacy behavior of the [ALTER TABLE RENAME] command such it 2269** behaves as it did prior to [version 3.24.0] (2018-06-04). See the 2270** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for 2271** additional information. This feature can also be turned on and off 2272** using the [PRAGMA legacy_alter_table] statement. 2273** </dd> 2274** 2275** [[SQLITE_DBCONFIG_DQS_DML]] 2276** <dt>SQLITE_DBCONFIG_DQS_DML</td> 2277** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates 2278** the legacy [double-quoted string literal] misfeature for DML statements 2279** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The 2280** default value of this setting is determined by the [-DSQLITE_DQS] 2281** compile-time option. 2282** </dd> 2283** 2284** [[SQLITE_DBCONFIG_DQS_DDL]] 2285** <dt>SQLITE_DBCONFIG_DQS_DDL</td> 2286** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates 2287** the legacy [double-quoted string literal] misfeature for DDL statements, 2288** such as CREATE TABLE and CREATE INDEX. The 2289** default value of this setting is determined by the [-DSQLITE_DQS] 2290** compile-time option. 2291** </dd> 2292** 2293** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]] 2294** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td> 2295** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to 2296** assume that database schemas are untainted by malicious content. 2297** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite 2298** takes additional defensive steps to protect the application from harm 2299** including: 2300** <ul> 2301** <li> Prohibit the use of SQL functions inside triggers, views, 2302** CHECK constraints, DEFAULT clauses, expression indexes, 2303** partial indexes, or generated columns 2304** unless those functions are tagged with [SQLITE_INNOCUOUS]. 2305** <li> Prohibit the use of virtual tables inside of triggers or views 2306** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS]. 2307** </ul> 2308** This setting defaults to "on" for legacy compatibility, however 2309** all applications are advised to turn it off if possible. This setting 2310** can also be controlled using the [PRAGMA trusted_schema] statement. 2311** </dd> 2312** 2313** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]] 2314** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td> 2315** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates 2316** the legacy file format flag. When activated, this flag causes all newly 2317** created database file to have a schema format version number (the 4-byte 2318** integer found at offset 44 into the database header) of 1. This in turn 2319** means that the resulting database file will be readable and writable by 2320** any SQLite version back to 3.0.0 ([dateof:3.0.0]). Without this setting, 2321** newly created databases are generally not understandable by SQLite versions 2322** prior to 3.3.0 ([dateof:3.3.0]). As these words are written, there 2323** is now scarcely any need to generated database files that are compatible 2324** all the way back to version 3.0.0, and so this setting is of little 2325** practical use, but is provided so that SQLite can continue to claim the 2326** ability to generate new database files that are compatible with version 2327** 3.0.0. 2328** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on, 2329** the [VACUUM] command will fail with an obscure error when attempting to 2330** process a table with generated columns and a descending index. This is 2331** not considered a bug since SQLite versions 3.3.0 and earlier do not support 2332** either generated columns or decending indexes. 2333** </dd> 2334** </dl> 2335*/ 2336#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2337#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2338#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2339#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2340#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2341#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2342#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2343#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2344#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2345#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */ 2346#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */ 2347#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */ 2348#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */ 2349#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */ 2350#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */ 2351#define SQLITE_DBCONFIG_ENABLE_VIEW 1015 /* int int* */ 2352#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT 1016 /* int int* */ 2353#define SQLITE_DBCONFIG_TRUSTED_SCHEMA 1017 /* int int* */ 2354#define SQLITE_DBCONFIG_MAX 1017 /* Largest DBCONFIG */ 2355 2356/* 2357** CAPI3REF: Enable Or Disable Extended Result Codes 2358** METHOD: sqlite3 2359** 2360** ^The sqlite3_extended_result_codes() routine enables or disables the 2361** [extended result codes] feature of SQLite. ^The extended result 2362** codes are disabled by default for historical compatibility. 2363*/ 2364int sqlite3_extended_result_codes(sqlite3*, int onoff); 2365 2366/* 2367** CAPI3REF: Last Insert Rowid 2368** METHOD: sqlite3 2369** 2370** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2371** has a unique 64-bit signed 2372** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2373** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2374** names are not also used by explicitly declared columns. ^If 2375** the table has a column of type [INTEGER PRIMARY KEY] then that column 2376** is another alias for the rowid. 2377** 2378** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2379** the most recent successful [INSERT] into a rowid table or [virtual table] 2380** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2381** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2382** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2383** zero. 2384** 2385** As well as being set automatically as rows are inserted into database 2386** tables, the value returned by this function may be set explicitly by 2387** [sqlite3_set_last_insert_rowid()] 2388** 2389** Some virtual table implementations may INSERT rows into rowid tables as 2390** part of committing a transaction (e.g. to flush data accumulated in memory 2391** to disk). In this case subsequent calls to this function return the rowid 2392** associated with these internal INSERT operations, which leads to 2393** unintuitive results. Virtual table implementations that do write to rowid 2394** tables in this way can avoid this problem by restoring the original 2395** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2396** control to the user. 2397** 2398** ^(If an [INSERT] occurs within a trigger then this routine will 2399** return the [rowid] of the inserted row as long as the trigger is 2400** running. Once the trigger program ends, the value returned 2401** by this routine reverts to what it was before the trigger was fired.)^ 2402** 2403** ^An [INSERT] that fails due to a constraint violation is not a 2404** successful [INSERT] and does not change the value returned by this 2405** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2406** and INSERT OR ABORT make no changes to the return value of this 2407** routine when their insertion fails. ^(When INSERT OR REPLACE 2408** encounters a constraint violation, it does not fail. The 2409** INSERT continues to completion after deleting rows that caused 2410** the constraint problem so INSERT OR REPLACE will always change 2411** the return value of this interface.)^ 2412** 2413** ^For the purposes of this routine, an [INSERT] is considered to 2414** be successful even if it is subsequently rolled back. 2415** 2416** This function is accessible to SQL statements via the 2417** [last_insert_rowid() SQL function]. 2418** 2419** If a separate thread performs a new [INSERT] on the same 2420** database connection while the [sqlite3_last_insert_rowid()] 2421** function is running and thus changes the last insert [rowid], 2422** then the value returned by [sqlite3_last_insert_rowid()] is 2423** unpredictable and might not equal either the old or the new 2424** last insert [rowid]. 2425*/ 2426sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2427 2428/* 2429** CAPI3REF: Set the Last Insert Rowid value. 2430** METHOD: sqlite3 2431** 2432** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2433** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2434** without inserting a row into the database. 2435*/ 2436void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2437 2438/* 2439** CAPI3REF: Count The Number Of Rows Modified 2440** METHOD: sqlite3 2441** 2442** ^This function returns the number of rows modified, inserted or 2443** deleted by the most recently completed INSERT, UPDATE or DELETE 2444** statement on the database connection specified by the only parameter. 2445** ^Executing any other type of SQL statement does not modify the value 2446** returned by this function. 2447** 2448** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2449** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2450** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2451** 2452** Changes to a view that are intercepted by 2453** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2454** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2455** DELETE statement run on a view is always zero. Only changes made to real 2456** tables are counted. 2457** 2458** Things are more complicated if the sqlite3_changes() function is 2459** executed while a trigger program is running. This may happen if the 2460** program uses the [changes() SQL function], or if some other callback 2461** function invokes sqlite3_changes() directly. Essentially: 2462** 2463** <ul> 2464** <li> ^(Before entering a trigger program the value returned by 2465** sqlite3_changes() function is saved. After the trigger program 2466** has finished, the original value is restored.)^ 2467** 2468** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2469** statement sets the value returned by sqlite3_changes() 2470** upon completion as normal. Of course, this value will not include 2471** any changes performed by sub-triggers, as the sqlite3_changes() 2472** value will be saved and restored after each sub-trigger has run.)^ 2473** </ul> 2474** 2475** ^This means that if the changes() SQL function (or similar) is used 2476** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2477** returns the value as set when the calling statement began executing. 2478** ^If it is used by the second or subsequent such statement within a trigger 2479** program, the value returned reflects the number of rows modified by the 2480** previous INSERT, UPDATE or DELETE statement within the same trigger. 2481** 2482** If a separate thread makes changes on the same database connection 2483** while [sqlite3_changes()] is running then the value returned 2484** is unpredictable and not meaningful. 2485** 2486** See also: 2487** <ul> 2488** <li> the [sqlite3_total_changes()] interface 2489** <li> the [count_changes pragma] 2490** <li> the [changes() SQL function] 2491** <li> the [data_version pragma] 2492** </ul> 2493*/ 2494int sqlite3_changes(sqlite3*); 2495 2496/* 2497** CAPI3REF: Total Number Of Rows Modified 2498** METHOD: sqlite3 2499** 2500** ^This function returns the total number of rows inserted, modified or 2501** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2502** since the database connection was opened, including those executed as 2503** part of trigger programs. ^Executing any other type of SQL statement 2504** does not affect the value returned by sqlite3_total_changes(). 2505** 2506** ^Changes made as part of [foreign key actions] are included in the 2507** count, but those made as part of REPLACE constraint resolution are 2508** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2509** are not counted. 2510** 2511** The [sqlite3_total_changes(D)] interface only reports the number 2512** of rows that changed due to SQL statement run against database 2513** connection D. Any changes by other database connections are ignored. 2514** To detect changes against a database file from other database 2515** connections use the [PRAGMA data_version] command or the 2516** [SQLITE_FCNTL_DATA_VERSION] [file control]. 2517** 2518** If a separate thread makes changes on the same database connection 2519** while [sqlite3_total_changes()] is running then the value 2520** returned is unpredictable and not meaningful. 2521** 2522** See also: 2523** <ul> 2524** <li> the [sqlite3_changes()] interface 2525** <li> the [count_changes pragma] 2526** <li> the [changes() SQL function] 2527** <li> the [data_version pragma] 2528** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control] 2529** </ul> 2530*/ 2531int sqlite3_total_changes(sqlite3*); 2532 2533/* 2534** CAPI3REF: Interrupt A Long-Running Query 2535** METHOD: sqlite3 2536** 2537** ^This function causes any pending database operation to abort and 2538** return at its earliest opportunity. This routine is typically 2539** called in response to a user action such as pressing "Cancel" 2540** or Ctrl-C where the user wants a long query operation to halt 2541** immediately. 2542** 2543** ^It is safe to call this routine from a thread different from the 2544** thread that is currently running the database operation. But it 2545** is not safe to call this routine with a [database connection] that 2546** is closed or might close before sqlite3_interrupt() returns. 2547** 2548** ^If an SQL operation is very nearly finished at the time when 2549** sqlite3_interrupt() is called, then it might not have an opportunity 2550** to be interrupted and might continue to completion. 2551** 2552** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2553** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2554** that is inside an explicit transaction, then the entire transaction 2555** will be rolled back automatically. 2556** 2557** ^The sqlite3_interrupt(D) call is in effect until all currently running 2558** SQL statements on [database connection] D complete. ^Any new SQL statements 2559** that are started after the sqlite3_interrupt() call and before the 2560** running statement count reaches zero are interrupted as if they had been 2561** running prior to the sqlite3_interrupt() call. ^New SQL statements 2562** that are started after the running statement count reaches zero are 2563** not effected by the sqlite3_interrupt(). 2564** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2565** SQL statements is a no-op and has no effect on SQL statements 2566** that are started after the sqlite3_interrupt() call returns. 2567*/ 2568void sqlite3_interrupt(sqlite3*); 2569 2570/* 2571** CAPI3REF: Determine If An SQL Statement Is Complete 2572** 2573** These routines are useful during command-line input to determine if the 2574** currently entered text seems to form a complete SQL statement or 2575** if additional input is needed before sending the text into 2576** SQLite for parsing. ^These routines return 1 if the input string 2577** appears to be a complete SQL statement. ^A statement is judged to be 2578** complete if it ends with a semicolon token and is not a prefix of a 2579** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2580** string literals or quoted identifier names or comments are not 2581** independent tokens (they are part of the token in which they are 2582** embedded) and thus do not count as a statement terminator. ^Whitespace 2583** and comments that follow the final semicolon are ignored. 2584** 2585** ^These routines return 0 if the statement is incomplete. ^If a 2586** memory allocation fails, then SQLITE_NOMEM is returned. 2587** 2588** ^These routines do not parse the SQL statements thus 2589** will not detect syntactically incorrect SQL. 2590** 2591** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2592** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2593** automatically by sqlite3_complete16(). If that initialization fails, 2594** then the return value from sqlite3_complete16() will be non-zero 2595** regardless of whether or not the input SQL is complete.)^ 2596** 2597** The input to [sqlite3_complete()] must be a zero-terminated 2598** UTF-8 string. 2599** 2600** The input to [sqlite3_complete16()] must be a zero-terminated 2601** UTF-16 string in native byte order. 2602*/ 2603int sqlite3_complete(const char *sql); 2604int sqlite3_complete16(const void *sql); 2605 2606/* 2607** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2608** KEYWORDS: {busy-handler callback} {busy handler} 2609** METHOD: sqlite3 2610** 2611** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2612** that might be invoked with argument P whenever 2613** an attempt is made to access a database table associated with 2614** [database connection] D when another thread 2615** or process has the table locked. 2616** The sqlite3_busy_handler() interface is used to implement 2617** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2618** 2619** ^If the busy callback is NULL, then [SQLITE_BUSY] 2620** is returned immediately upon encountering the lock. ^If the busy callback 2621** is not NULL, then the callback might be invoked with two arguments. 2622** 2623** ^The first argument to the busy handler is a copy of the void* pointer which 2624** is the third argument to sqlite3_busy_handler(). ^The second argument to 2625** the busy handler callback is the number of times that the busy handler has 2626** been invoked previously for the same locking event. ^If the 2627** busy callback returns 0, then no additional attempts are made to 2628** access the database and [SQLITE_BUSY] is returned 2629** to the application. 2630** ^If the callback returns non-zero, then another attempt 2631** is made to access the database and the cycle repeats. 2632** 2633** The presence of a busy handler does not guarantee that it will be invoked 2634** when there is lock contention. ^If SQLite determines that invoking the busy 2635** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2636** to the application instead of invoking the 2637** busy handler. 2638** Consider a scenario where one process is holding a read lock that 2639** it is trying to promote to a reserved lock and 2640** a second process is holding a reserved lock that it is trying 2641** to promote to an exclusive lock. The first process cannot proceed 2642** because it is blocked by the second and the second process cannot 2643** proceed because it is blocked by the first. If both processes 2644** invoke the busy handlers, neither will make any progress. Therefore, 2645** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2646** will induce the first process to release its read lock and allow 2647** the second process to proceed. 2648** 2649** ^The default busy callback is NULL. 2650** 2651** ^(There can only be a single busy handler defined for each 2652** [database connection]. Setting a new busy handler clears any 2653** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2654** or evaluating [PRAGMA busy_timeout=N] will change the 2655** busy handler and thus clear any previously set busy handler. 2656** 2657** The busy callback should not take any actions which modify the 2658** database connection that invoked the busy handler. In other words, 2659** the busy handler is not reentrant. Any such actions 2660** result in undefined behavior. 2661** 2662** A busy handler must not close the database connection 2663** or [prepared statement] that invoked the busy handler. 2664*/ 2665int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2666 2667/* 2668** CAPI3REF: Set A Busy Timeout 2669** METHOD: sqlite3 2670** 2671** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2672** for a specified amount of time when a table is locked. ^The handler 2673** will sleep multiple times until at least "ms" milliseconds of sleeping 2674** have accumulated. ^After at least "ms" milliseconds of sleeping, 2675** the handler returns 0 which causes [sqlite3_step()] to return 2676** [SQLITE_BUSY]. 2677** 2678** ^Calling this routine with an argument less than or equal to zero 2679** turns off all busy handlers. 2680** 2681** ^(There can only be a single busy handler for a particular 2682** [database connection] at any given moment. If another busy handler 2683** was defined (using [sqlite3_busy_handler()]) prior to calling 2684** this routine, that other busy handler is cleared.)^ 2685** 2686** See also: [PRAGMA busy_timeout] 2687*/ 2688int sqlite3_busy_timeout(sqlite3*, int ms); 2689 2690/* 2691** CAPI3REF: Convenience Routines For Running Queries 2692** METHOD: sqlite3 2693** 2694** This is a legacy interface that is preserved for backwards compatibility. 2695** Use of this interface is not recommended. 2696** 2697** Definition: A <b>result table</b> is memory data structure created by the 2698** [sqlite3_get_table()] interface. A result table records the 2699** complete query results from one or more queries. 2700** 2701** The table conceptually has a number of rows and columns. But 2702** these numbers are not part of the result table itself. These 2703** numbers are obtained separately. Let N be the number of rows 2704** and M be the number of columns. 2705** 2706** A result table is an array of pointers to zero-terminated UTF-8 strings. 2707** There are (N+1)*M elements in the array. The first M pointers point 2708** to zero-terminated strings that contain the names of the columns. 2709** The remaining entries all point to query results. NULL values result 2710** in NULL pointers. All other values are in their UTF-8 zero-terminated 2711** string representation as returned by [sqlite3_column_text()]. 2712** 2713** A result table might consist of one or more memory allocations. 2714** It is not safe to pass a result table directly to [sqlite3_free()]. 2715** A result table should be deallocated using [sqlite3_free_table()]. 2716** 2717** ^(As an example of the result table format, suppose a query result 2718** is as follows: 2719** 2720** <blockquote><pre> 2721** Name | Age 2722** ----------------------- 2723** Alice | 43 2724** Bob | 28 2725** Cindy | 21 2726** </pre></blockquote> 2727** 2728** There are two columns (M==2) and three rows (N==3). Thus the 2729** result table has 8 entries. Suppose the result table is stored 2730** in an array named azResult. Then azResult holds this content: 2731** 2732** <blockquote><pre> 2733** azResult[0] = "Name"; 2734** azResult[1] = "Age"; 2735** azResult[2] = "Alice"; 2736** azResult[3] = "43"; 2737** azResult[4] = "Bob"; 2738** azResult[5] = "28"; 2739** azResult[6] = "Cindy"; 2740** azResult[7] = "21"; 2741** </pre></blockquote>)^ 2742** 2743** ^The sqlite3_get_table() function evaluates one or more 2744** semicolon-separated SQL statements in the zero-terminated UTF-8 2745** string of its 2nd parameter and returns a result table to the 2746** pointer given in its 3rd parameter. 2747** 2748** After the application has finished with the result from sqlite3_get_table(), 2749** it must pass the result table pointer to sqlite3_free_table() in order to 2750** release the memory that was malloced. Because of the way the 2751** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2752** function must not try to call [sqlite3_free()] directly. Only 2753** [sqlite3_free_table()] is able to release the memory properly and safely. 2754** 2755** The sqlite3_get_table() interface is implemented as a wrapper around 2756** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2757** to any internal data structures of SQLite. It uses only the public 2758** interface defined here. As a consequence, errors that occur in the 2759** wrapper layer outside of the internal [sqlite3_exec()] call are not 2760** reflected in subsequent calls to [sqlite3_errcode()] or 2761** [sqlite3_errmsg()]. 2762*/ 2763int sqlite3_get_table( 2764 sqlite3 *db, /* An open database */ 2765 const char *zSql, /* SQL to be evaluated */ 2766 char ***pazResult, /* Results of the query */ 2767 int *pnRow, /* Number of result rows written here */ 2768 int *pnColumn, /* Number of result columns written here */ 2769 char **pzErrmsg /* Error msg written here */ 2770); 2771void sqlite3_free_table(char **result); 2772 2773/* 2774** CAPI3REF: Formatted String Printing Functions 2775** 2776** These routines are work-alikes of the "printf()" family of functions 2777** from the standard C library. 2778** These routines understand most of the common formatting options from 2779** the standard library printf() 2780** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2781** See the [built-in printf()] documentation for details. 2782** 2783** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2784** results into memory obtained from [sqlite3_malloc64()]. 2785** The strings returned by these two routines should be 2786** released by [sqlite3_free()]. ^Both routines return a 2787** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2788** memory to hold the resulting string. 2789** 2790** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2791** the standard C library. The result is written into the 2792** buffer supplied as the second parameter whose size is given by 2793** the first parameter. Note that the order of the 2794** first two parameters is reversed from snprintf().)^ This is an 2795** historical accident that cannot be fixed without breaking 2796** backwards compatibility. ^(Note also that sqlite3_snprintf() 2797** returns a pointer to its buffer instead of the number of 2798** characters actually written into the buffer.)^ We admit that 2799** the number of characters written would be a more useful return 2800** value but we cannot change the implementation of sqlite3_snprintf() 2801** now without breaking compatibility. 2802** 2803** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2804** guarantees that the buffer is always zero-terminated. ^The first 2805** parameter "n" is the total size of the buffer, including space for 2806** the zero terminator. So the longest string that can be completely 2807** written will be n-1 characters. 2808** 2809** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2810** 2811** See also: [built-in printf()], [printf() SQL function] 2812*/ 2813char *sqlite3_mprintf(const char*,...); 2814char *sqlite3_vmprintf(const char*, va_list); 2815char *sqlite3_snprintf(int,char*,const char*, ...); 2816char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2817 2818/* 2819** CAPI3REF: Memory Allocation Subsystem 2820** 2821** The SQLite core uses these three routines for all of its own 2822** internal memory allocation needs. "Core" in the previous sentence 2823** does not include operating-system specific [VFS] implementation. The 2824** Windows VFS uses native malloc() and free() for some operations. 2825** 2826** ^The sqlite3_malloc() routine returns a pointer to a block 2827** of memory at least N bytes in length, where N is the parameter. 2828** ^If sqlite3_malloc() is unable to obtain sufficient free 2829** memory, it returns a NULL pointer. ^If the parameter N to 2830** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2831** a NULL pointer. 2832** 2833** ^The sqlite3_malloc64(N) routine works just like 2834** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2835** of a signed 32-bit integer. 2836** 2837** ^Calling sqlite3_free() with a pointer previously returned 2838** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2839** that it might be reused. ^The sqlite3_free() routine is 2840** a no-op if is called with a NULL pointer. Passing a NULL pointer 2841** to sqlite3_free() is harmless. After being freed, memory 2842** should neither be read nor written. Even reading previously freed 2843** memory might result in a segmentation fault or other severe error. 2844** Memory corruption, a segmentation fault, or other severe error 2845** might result if sqlite3_free() is called with a non-NULL pointer that 2846** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2847** 2848** ^The sqlite3_realloc(X,N) interface attempts to resize a 2849** prior memory allocation X to be at least N bytes. 2850** ^If the X parameter to sqlite3_realloc(X,N) 2851** is a NULL pointer then its behavior is identical to calling 2852** sqlite3_malloc(N). 2853** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2854** negative then the behavior is exactly the same as calling 2855** sqlite3_free(X). 2856** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2857** of at least N bytes in size or NULL if insufficient memory is available. 2858** ^If M is the size of the prior allocation, then min(N,M) bytes 2859** of the prior allocation are copied into the beginning of buffer returned 2860** by sqlite3_realloc(X,N) and the prior allocation is freed. 2861** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2862** prior allocation is not freed. 2863** 2864** ^The sqlite3_realloc64(X,N) interfaces works the same as 2865** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2866** of a 32-bit signed integer. 2867** 2868** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2869** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2870** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2871** ^The value returned by sqlite3_msize(X) might be larger than the number 2872** of bytes requested when X was allocated. ^If X is a NULL pointer then 2873** sqlite3_msize(X) returns zero. If X points to something that is not 2874** the beginning of memory allocation, or if it points to a formerly 2875** valid memory allocation that has now been freed, then the behavior 2876** of sqlite3_msize(X) is undefined and possibly harmful. 2877** 2878** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2879** sqlite3_malloc64(), and sqlite3_realloc64() 2880** is always aligned to at least an 8 byte boundary, or to a 2881** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2882** option is used. 2883** 2884** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2885** must be either NULL or else pointers obtained from a prior 2886** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2887** not yet been released. 2888** 2889** The application must not read or write any part of 2890** a block of memory after it has been released using 2891** [sqlite3_free()] or [sqlite3_realloc()]. 2892*/ 2893void *sqlite3_malloc(int); 2894void *sqlite3_malloc64(sqlite3_uint64); 2895void *sqlite3_realloc(void*, int); 2896void *sqlite3_realloc64(void*, sqlite3_uint64); 2897void sqlite3_free(void*); 2898sqlite3_uint64 sqlite3_msize(void*); 2899 2900/* 2901** CAPI3REF: Memory Allocator Statistics 2902** 2903** SQLite provides these two interfaces for reporting on the status 2904** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2905** routines, which form the built-in memory allocation subsystem. 2906** 2907** ^The [sqlite3_memory_used()] routine returns the number of bytes 2908** of memory currently outstanding (malloced but not freed). 2909** ^The [sqlite3_memory_highwater()] routine returns the maximum 2910** value of [sqlite3_memory_used()] since the high-water mark 2911** was last reset. ^The values returned by [sqlite3_memory_used()] and 2912** [sqlite3_memory_highwater()] include any overhead 2913** added by SQLite in its implementation of [sqlite3_malloc()], 2914** but not overhead added by the any underlying system library 2915** routines that [sqlite3_malloc()] may call. 2916** 2917** ^The memory high-water mark is reset to the current value of 2918** [sqlite3_memory_used()] if and only if the parameter to 2919** [sqlite3_memory_highwater()] is true. ^The value returned 2920** by [sqlite3_memory_highwater(1)] is the high-water mark 2921** prior to the reset. 2922*/ 2923sqlite3_int64 sqlite3_memory_used(void); 2924sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2925 2926/* 2927** CAPI3REF: Pseudo-Random Number Generator 2928** 2929** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2930** select random [ROWID | ROWIDs] when inserting new records into a table that 2931** already uses the largest possible [ROWID]. The PRNG is also used for 2932** the built-in random() and randomblob() SQL functions. This interface allows 2933** applications to access the same PRNG for other purposes. 2934** 2935** ^A call to this routine stores N bytes of randomness into buffer P. 2936** ^The P parameter can be a NULL pointer. 2937** 2938** ^If this routine has not been previously called or if the previous 2939** call had N less than one or a NULL pointer for P, then the PRNG is 2940** seeded using randomness obtained from the xRandomness method of 2941** the default [sqlite3_vfs] object. 2942** ^If the previous call to this routine had an N of 1 or more and a 2943** non-NULL P then the pseudo-randomness is generated 2944** internally and without recourse to the [sqlite3_vfs] xRandomness 2945** method. 2946*/ 2947void sqlite3_randomness(int N, void *P); 2948 2949/* 2950** CAPI3REF: Compile-Time Authorization Callbacks 2951** METHOD: sqlite3 2952** KEYWORDS: {authorizer callback} 2953** 2954** ^This routine registers an authorizer callback with a particular 2955** [database connection], supplied in the first argument. 2956** ^The authorizer callback is invoked as SQL statements are being compiled 2957** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2958** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2959** and [sqlite3_prepare16_v3()]. ^At various 2960** points during the compilation process, as logic is being created 2961** to perform various actions, the authorizer callback is invoked to 2962** see if those actions are allowed. ^The authorizer callback should 2963** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2964** specific action but allow the SQL statement to continue to be 2965** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2966** rejected with an error. ^If the authorizer callback returns 2967** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2968** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2969** the authorizer will fail with an error message. 2970** 2971** When the callback returns [SQLITE_OK], that means the operation 2972** requested is ok. ^When the callback returns [SQLITE_DENY], the 2973** [sqlite3_prepare_v2()] or equivalent call that triggered the 2974** authorizer will fail with an error message explaining that 2975** access is denied. 2976** 2977** ^The first parameter to the authorizer callback is a copy of the third 2978** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2979** to the callback is an integer [SQLITE_COPY | action code] that specifies 2980** the particular action to be authorized. ^The third through sixth parameters 2981** to the callback are either NULL pointers or zero-terminated strings 2982** that contain additional details about the action to be authorized. 2983** Applications must always be prepared to encounter a NULL pointer in any 2984** of the third through the sixth parameters of the authorization callback. 2985** 2986** ^If the action code is [SQLITE_READ] 2987** and the callback returns [SQLITE_IGNORE] then the 2988** [prepared statement] statement is constructed to substitute 2989** a NULL value in place of the table column that would have 2990** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2991** return can be used to deny an untrusted user access to individual 2992** columns of a table. 2993** ^When a table is referenced by a [SELECT] but no column values are 2994** extracted from that table (for example in a query like 2995** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2996** is invoked once for that table with a column name that is an empty string. 2997** ^If the action code is [SQLITE_DELETE] and the callback returns 2998** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2999** [truncate optimization] is disabled and all rows are deleted individually. 3000** 3001** An authorizer is used when [sqlite3_prepare | preparing] 3002** SQL statements from an untrusted source, to ensure that the SQL statements 3003** do not try to access data they are not allowed to see, or that they do not 3004** try to execute malicious statements that damage the database. For 3005** example, an application may allow a user to enter arbitrary 3006** SQL queries for evaluation by a database. But the application does 3007** not want the user to be able to make arbitrary changes to the 3008** database. An authorizer could then be put in place while the 3009** user-entered SQL is being [sqlite3_prepare | prepared] that 3010** disallows everything except [SELECT] statements. 3011** 3012** Applications that need to process SQL from untrusted sources 3013** might also consider lowering resource limits using [sqlite3_limit()] 3014** and limiting database size using the [max_page_count] [PRAGMA] 3015** in addition to using an authorizer. 3016** 3017** ^(Only a single authorizer can be in place on a database connection 3018** at a time. Each call to sqlite3_set_authorizer overrides the 3019** previous call.)^ ^Disable the authorizer by installing a NULL callback. 3020** The authorizer is disabled by default. 3021** 3022** The authorizer callback must not do anything that will modify 3023** the database connection that invoked the authorizer callback. 3024** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3025** database connections for the meaning of "modify" in this paragraph. 3026** 3027** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 3028** statement might be re-prepared during [sqlite3_step()] due to a 3029** schema change. Hence, the application should ensure that the 3030** correct authorizer callback remains in place during the [sqlite3_step()]. 3031** 3032** ^Note that the authorizer callback is invoked only during 3033** [sqlite3_prepare()] or its variants. Authorization is not 3034** performed during statement evaluation in [sqlite3_step()], unless 3035** as stated in the previous paragraph, sqlite3_step() invokes 3036** sqlite3_prepare_v2() to reprepare a statement after a schema change. 3037*/ 3038int sqlite3_set_authorizer( 3039 sqlite3*, 3040 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 3041 void *pUserData 3042); 3043 3044/* 3045** CAPI3REF: Authorizer Return Codes 3046** 3047** The [sqlite3_set_authorizer | authorizer callback function] must 3048** return either [SQLITE_OK] or one of these two constants in order 3049** to signal SQLite whether or not the action is permitted. See the 3050** [sqlite3_set_authorizer | authorizer documentation] for additional 3051** information. 3052** 3053** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 3054** returned from the [sqlite3_vtab_on_conflict()] interface. 3055*/ 3056#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 3057#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 3058 3059/* 3060** CAPI3REF: Authorizer Action Codes 3061** 3062** The [sqlite3_set_authorizer()] interface registers a callback function 3063** that is invoked to authorize certain SQL statement actions. The 3064** second parameter to the callback is an integer code that specifies 3065** what action is being authorized. These are the integer action codes that 3066** the authorizer callback may be passed. 3067** 3068** These action code values signify what kind of operation is to be 3069** authorized. The 3rd and 4th parameters to the authorization 3070** callback function will be parameters or NULL depending on which of these 3071** codes is used as the second parameter. ^(The 5th parameter to the 3072** authorizer callback is the name of the database ("main", "temp", 3073** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 3074** is the name of the inner-most trigger or view that is responsible for 3075** the access attempt or NULL if this access attempt is directly from 3076** top-level SQL code. 3077*/ 3078/******************************************* 3rd ************ 4th ***********/ 3079#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 3080#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 3081#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 3082#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 3083#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 3084#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 3085#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 3086#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 3087#define SQLITE_DELETE 9 /* Table Name NULL */ 3088#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 3089#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 3090#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 3091#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 3092#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 3093#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 3094#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 3095#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 3096#define SQLITE_INSERT 18 /* Table Name NULL */ 3097#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 3098#define SQLITE_READ 20 /* Table Name Column Name */ 3099#define SQLITE_SELECT 21 /* NULL NULL */ 3100#define SQLITE_TRANSACTION 22 /* Operation NULL */ 3101#define SQLITE_UPDATE 23 /* Table Name Column Name */ 3102#define SQLITE_ATTACH 24 /* Filename NULL */ 3103#define SQLITE_DETACH 25 /* Database Name NULL */ 3104#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 3105#define SQLITE_REINDEX 27 /* Index Name NULL */ 3106#define SQLITE_ANALYZE 28 /* Table Name NULL */ 3107#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 3108#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 3109#define SQLITE_FUNCTION 31 /* NULL Function Name */ 3110#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 3111#define SQLITE_COPY 0 /* No longer used */ 3112#define SQLITE_RECURSIVE 33 /* NULL NULL */ 3113 3114/* 3115** CAPI3REF: Tracing And Profiling Functions 3116** METHOD: sqlite3 3117** 3118** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 3119** instead of the routines described here. 3120** 3121** These routines register callback functions that can be used for 3122** tracing and profiling the execution of SQL statements. 3123** 3124** ^The callback function registered by sqlite3_trace() is invoked at 3125** various times when an SQL statement is being run by [sqlite3_step()]. 3126** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 3127** SQL statement text as the statement first begins executing. 3128** ^(Additional sqlite3_trace() callbacks might occur 3129** as each triggered subprogram is entered. The callbacks for triggers 3130** contain a UTF-8 SQL comment that identifies the trigger.)^ 3131** 3132** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 3133** the length of [bound parameter] expansion in the output of sqlite3_trace(). 3134** 3135** ^The callback function registered by sqlite3_profile() is invoked 3136** as each SQL statement finishes. ^The profile callback contains 3137** the original statement text and an estimate of wall-clock time 3138** of how long that statement took to run. ^The profile callback 3139** time is in units of nanoseconds, however the current implementation 3140** is only capable of millisecond resolution so the six least significant 3141** digits in the time are meaningless. Future versions of SQLite 3142** might provide greater resolution on the profiler callback. Invoking 3143** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the 3144** profile callback. 3145*/ 3146SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 3147 void(*xTrace)(void*,const char*), void*); 3148SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 3149 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 3150 3151/* 3152** CAPI3REF: SQL Trace Event Codes 3153** KEYWORDS: SQLITE_TRACE 3154** 3155** These constants identify classes of events that can be monitored 3156** using the [sqlite3_trace_v2()] tracing logic. The M argument 3157** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 3158** the following constants. ^The first argument to the trace callback 3159** is one of the following constants. 3160** 3161** New tracing constants may be added in future releases. 3162** 3163** ^A trace callback has four arguments: xCallback(T,C,P,X). 3164** ^The T argument is one of the integer type codes above. 3165** ^The C argument is a copy of the context pointer passed in as the 3166** fourth argument to [sqlite3_trace_v2()]. 3167** The P and X arguments are pointers whose meanings depend on T. 3168** 3169** <dl> 3170** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 3171** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 3172** first begins running and possibly at other times during the 3173** execution of the prepared statement, such as at the start of each 3174** trigger subprogram. ^The P argument is a pointer to the 3175** [prepared statement]. ^The X argument is a pointer to a string which 3176** is the unexpanded SQL text of the prepared statement or an SQL comment 3177** that indicates the invocation of a trigger. ^The callback can compute 3178** the same text that would have been returned by the legacy [sqlite3_trace()] 3179** interface by using the X argument when X begins with "--" and invoking 3180** [sqlite3_expanded_sql(P)] otherwise. 3181** 3182** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 3183** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 3184** information as is provided by the [sqlite3_profile()] callback. 3185** ^The P argument is a pointer to the [prepared statement] and the 3186** X argument points to a 64-bit integer which is the estimated of 3187** the number of nanosecond that the prepared statement took to run. 3188** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 3189** 3190** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 3191** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 3192** statement generates a single row of result. 3193** ^The P argument is a pointer to the [prepared statement] and the 3194** X argument is unused. 3195** 3196** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 3197** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 3198** connection closes. 3199** ^The P argument is a pointer to the [database connection] object 3200** and the X argument is unused. 3201** </dl> 3202*/ 3203#define SQLITE_TRACE_STMT 0x01 3204#define SQLITE_TRACE_PROFILE 0x02 3205#define SQLITE_TRACE_ROW 0x04 3206#define SQLITE_TRACE_CLOSE 0x08 3207 3208/* 3209** CAPI3REF: SQL Trace Hook 3210** METHOD: sqlite3 3211** 3212** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3213** function X against [database connection] D, using property mask M 3214** and context pointer P. ^If the X callback is 3215** NULL or if the M mask is zero, then tracing is disabled. The 3216** M argument should be the bitwise OR-ed combination of 3217** zero or more [SQLITE_TRACE] constants. 3218** 3219** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3220** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3221** 3222** ^The X callback is invoked whenever any of the events identified by 3223** mask M occur. ^The integer return value from the callback is currently 3224** ignored, though this may change in future releases. Callback 3225** implementations should return zero to ensure future compatibility. 3226** 3227** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3228** ^The T argument is one of the [SQLITE_TRACE] 3229** constants to indicate why the callback was invoked. 3230** ^The C argument is a copy of the context pointer. 3231** The P and X arguments are pointers whose meanings depend on T. 3232** 3233** The sqlite3_trace_v2() interface is intended to replace the legacy 3234** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3235** are deprecated. 3236*/ 3237int sqlite3_trace_v2( 3238 sqlite3*, 3239 unsigned uMask, 3240 int(*xCallback)(unsigned,void*,void*,void*), 3241 void *pCtx 3242); 3243 3244/* 3245** CAPI3REF: Query Progress Callbacks 3246** METHOD: sqlite3 3247** 3248** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3249** function X to be invoked periodically during long running calls to 3250** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3251** database connection D. An example use for this 3252** interface is to keep a GUI updated during a large query. 3253** 3254** ^The parameter P is passed through as the only parameter to the 3255** callback function X. ^The parameter N is the approximate number of 3256** [virtual machine instructions] that are evaluated between successive 3257** invocations of the callback X. ^If N is less than one then the progress 3258** handler is disabled. 3259** 3260** ^Only a single progress handler may be defined at one time per 3261** [database connection]; setting a new progress handler cancels the 3262** old one. ^Setting parameter X to NULL disables the progress handler. 3263** ^The progress handler is also disabled by setting N to a value less 3264** than 1. 3265** 3266** ^If the progress callback returns non-zero, the operation is 3267** interrupted. This feature can be used to implement a 3268** "Cancel" button on a GUI progress dialog box. 3269** 3270** The progress handler callback must not do anything that will modify 3271** the database connection that invoked the progress handler. 3272** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3273** database connections for the meaning of "modify" in this paragraph. 3274** 3275*/ 3276void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3277 3278/* 3279** CAPI3REF: Opening A New Database Connection 3280** CONSTRUCTOR: sqlite3 3281** 3282** ^These routines open an SQLite database file as specified by the 3283** filename argument. ^The filename argument is interpreted as UTF-8 for 3284** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3285** order for sqlite3_open16(). ^(A [database connection] handle is usually 3286** returned in *ppDb, even if an error occurs. The only exception is that 3287** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3288** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3289** object.)^ ^(If the database is opened (and/or created) successfully, then 3290** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3291** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3292** an English language description of the error following a failure of any 3293** of the sqlite3_open() routines. 3294** 3295** ^The default encoding will be UTF-8 for databases created using 3296** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3297** created using sqlite3_open16() will be UTF-16 in the native byte order. 3298** 3299** Whether or not an error occurs when it is opened, resources 3300** associated with the [database connection] handle should be released by 3301** passing it to [sqlite3_close()] when it is no longer required. 3302** 3303** The sqlite3_open_v2() interface works like sqlite3_open() 3304** except that it accepts two additional parameters for additional control 3305** over the new database connection. ^(The flags parameter to 3306** sqlite3_open_v2() must include, at a minimum, one of the following 3307** three flag combinations:)^ 3308** 3309** <dl> 3310** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3311** <dd>The database is opened in read-only mode. If the database does not 3312** already exist, an error is returned.</dd>)^ 3313** 3314** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3315** <dd>The database is opened for reading and writing if possible, or reading 3316** only if the file is write protected by the operating system. In either 3317** case the database must already exist, otherwise an error is returned.</dd>)^ 3318** 3319** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3320** <dd>The database is opened for reading and writing, and is created if 3321** it does not already exist. This is the behavior that is always used for 3322** sqlite3_open() and sqlite3_open16().</dd>)^ 3323** </dl> 3324** 3325** In addition to the required flags, the following optional flags are 3326** also supported: 3327** 3328** <dl> 3329** ^(<dt>[SQLITE_OPEN_URI]</dt> 3330** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^ 3331** 3332** ^(<dt>[SQLITE_OPEN_MEMORY]</dt> 3333** <dd>The database will be opened as an in-memory database. The database 3334** is named by the "filename" argument for the purposes of cache-sharing, 3335** if shared cache mode is enabled, but the "filename" is otherwise ignored. 3336** </dd>)^ 3337** 3338** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt> 3339** <dd>The new database connection will use the "multi-thread" 3340** [threading mode].)^ This means that separate threads are allowed 3341** to use SQLite at the same time, as long as each thread is using 3342** a different [database connection]. 3343** 3344** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt> 3345** <dd>The new database connection will use the "serialized" 3346** [threading mode].)^ This means the multiple threads can safely 3347** attempt to use the same database connection at the same time. 3348** (Mutexes will block any actual concurrency, but in this mode 3349** there is no harm in trying.) 3350** 3351** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt> 3352** <dd>The database is opened [shared cache] enabled, overriding 3353** the default shared cache setting provided by 3354** [sqlite3_enable_shared_cache()].)^ 3355** 3356** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt> 3357** <dd>The database is opened [shared cache] disabled, overriding 3358** the default shared cache setting provided by 3359** [sqlite3_enable_shared_cache()].)^ 3360** 3361** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt> 3362** <dd>The database filename is not allowed to be a symbolic link</dd> 3363** </dl>)^ 3364** 3365** If the 3rd parameter to sqlite3_open_v2() is not one of the 3366** required combinations shown above optionally combined with other 3367** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3368** then the behavior is undefined. 3369** 3370** ^The fourth parameter to sqlite3_open_v2() is the name of the 3371** [sqlite3_vfs] object that defines the operating system interface that 3372** the new database connection should use. ^If the fourth parameter is 3373** a NULL pointer then the default [sqlite3_vfs] object is used. 3374** 3375** ^If the filename is ":memory:", then a private, temporary in-memory database 3376** is created for the connection. ^This in-memory database will vanish when 3377** the database connection is closed. Future versions of SQLite might 3378** make use of additional special filenames that begin with the ":" character. 3379** It is recommended that when a database filename actually does begin with 3380** a ":" character you should prefix the filename with a pathname such as 3381** "./" to avoid ambiguity. 3382** 3383** ^If the filename is an empty string, then a private, temporary 3384** on-disk database will be created. ^This private database will be 3385** automatically deleted as soon as the database connection is closed. 3386** 3387** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3388** 3389** ^If [URI filename] interpretation is enabled, and the filename argument 3390** begins with "file:", then the filename is interpreted as a URI. ^URI 3391** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3392** set in the third argument to sqlite3_open_v2(), or if it has 3393** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3394** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3395** URI filename interpretation is turned off 3396** by default, but future releases of SQLite might enable URI filename 3397** interpretation by default. See "[URI filenames]" for additional 3398** information. 3399** 3400** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3401** authority, then it must be either an empty string or the string 3402** "localhost". ^If the authority is not an empty string or "localhost", an 3403** error is returned to the caller. ^The fragment component of a URI, if 3404** present, is ignored. 3405** 3406** ^SQLite uses the path component of the URI as the name of the disk file 3407** which contains the database. ^If the path begins with a '/' character, 3408** then it is interpreted as an absolute path. ^If the path does not begin 3409** with a '/' (meaning that the authority section is omitted from the URI) 3410** then the path is interpreted as a relative path. 3411** ^(On windows, the first component of an absolute path 3412** is a drive specification (e.g. "C:").)^ 3413** 3414** [[core URI query parameters]] 3415** The query component of a URI may contain parameters that are interpreted 3416** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3417** SQLite and its built-in [VFSes] interpret the 3418** following query parameters: 3419** 3420** <ul> 3421** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3422** a VFS object that provides the operating system interface that should 3423** be used to access the database file on disk. ^If this option is set to 3424** an empty string the default VFS object is used. ^Specifying an unknown 3425** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3426** present, then the VFS specified by the option takes precedence over 3427** the value passed as the fourth parameter to sqlite3_open_v2(). 3428** 3429** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3430** "rwc", or "memory". Attempting to set it to any other value is 3431** an error)^. 3432** ^If "ro" is specified, then the database is opened for read-only 3433** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3434** third argument to sqlite3_open_v2(). ^If the mode option is set to 3435** "rw", then the database is opened for read-write (but not create) 3436** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3437** been set. ^Value "rwc" is equivalent to setting both 3438** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3439** set to "memory" then a pure [in-memory database] that never reads 3440** or writes from disk is used. ^It is an error to specify a value for 3441** the mode parameter that is less restrictive than that specified by 3442** the flags passed in the third parameter to sqlite3_open_v2(). 3443** 3444** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3445** "private". ^Setting it to "shared" is equivalent to setting the 3446** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3447** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3448** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3449** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3450** a URI filename, its value overrides any behavior requested by setting 3451** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3452** 3453** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3454** [powersafe overwrite] property does or does not apply to the 3455** storage media on which the database file resides. 3456** 3457** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3458** which if set disables file locking in rollback journal modes. This 3459** is useful for accessing a database on a filesystem that does not 3460** support locking. Caution: Database corruption might result if two 3461** or more processes write to the same database and any one of those 3462** processes uses nolock=1. 3463** 3464** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3465** parameter that indicates that the database file is stored on 3466** read-only media. ^When immutable is set, SQLite assumes that the 3467** database file cannot be changed, even by a process with higher 3468** privilege, and so the database is opened read-only and all locking 3469** and change detection is disabled. Caution: Setting the immutable 3470** property on a database file that does in fact change can result 3471** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3472** See also: [SQLITE_IOCAP_IMMUTABLE]. 3473** 3474** </ul> 3475** 3476** ^Specifying an unknown parameter in the query component of a URI is not an 3477** error. Future versions of SQLite might understand additional query 3478** parameters. See "[query parameters with special meaning to SQLite]" for 3479** additional information. 3480** 3481** [[URI filename examples]] <h3>URI filename examples</h3> 3482** 3483** <table border="1" align=center cellpadding=5> 3484** <tr><th> URI filenames <th> Results 3485** <tr><td> file:data.db <td> 3486** Open the file "data.db" in the current directory. 3487** <tr><td> file:/home/fred/data.db<br> 3488** file:///home/fred/data.db <br> 3489** file://localhost/home/fred/data.db <br> <td> 3490** Open the database file "/home/fred/data.db". 3491** <tr><td> file://darkstar/home/fred/data.db <td> 3492** An error. "darkstar" is not a recognized authority. 3493** <tr><td style="white-space:nowrap"> 3494** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3495** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3496** C:. Note that the %20 escaping in this example is not strictly 3497** necessary - space characters can be used literally 3498** in URI filenames. 3499** <tr><td> file:data.db?mode=ro&cache=private <td> 3500** Open file "data.db" in the current directory for read-only access. 3501** Regardless of whether or not shared-cache mode is enabled by 3502** default, use a private cache. 3503** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3504** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3505** that uses dot-files in place of posix advisory locking. 3506** <tr><td> file:data.db?mode=readonly <td> 3507** An error. "readonly" is not a valid option for the "mode" parameter. 3508** Use "ro" instead: "file:data.db?mode=ro". 3509** </table> 3510** 3511** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3512** query components of a URI. A hexadecimal escape sequence consists of a 3513** percent sign - "%" - followed by exactly two hexadecimal digits 3514** specifying an octet value. ^Before the path or query components of a 3515** URI filename are interpreted, they are encoded using UTF-8 and all 3516** hexadecimal escape sequences replaced by a single byte containing the 3517** corresponding octet. If this process generates an invalid UTF-8 encoding, 3518** the results are undefined. 3519** 3520** <b>Note to Windows users:</b> The encoding used for the filename argument 3521** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3522** codepage is currently defined. Filenames containing international 3523** characters must be converted to UTF-8 prior to passing them into 3524** sqlite3_open() or sqlite3_open_v2(). 3525** 3526** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3527** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3528** features that require the use of temporary files may fail. 3529** 3530** See also: [sqlite3_temp_directory] 3531*/ 3532int sqlite3_open( 3533 const char *filename, /* Database filename (UTF-8) */ 3534 sqlite3 **ppDb /* OUT: SQLite db handle */ 3535); 3536int sqlite3_open16( 3537 const void *filename, /* Database filename (UTF-16) */ 3538 sqlite3 **ppDb /* OUT: SQLite db handle */ 3539); 3540int sqlite3_open_v2( 3541 const char *filename, /* Database filename (UTF-8) */ 3542 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3543 int flags, /* Flags */ 3544 const char *zVfs /* Name of VFS module to use */ 3545); 3546 3547/* 3548** CAPI3REF: Obtain Values For URI Parameters 3549** 3550** These are utility routines, useful to [VFS|custom VFS implementations], 3551** that check if a database file was a URI that contained a specific query 3552** parameter, and if so obtains the value of that query parameter. 3553** 3554** The first parameter to these interfaces (hereafter referred to 3555** as F) must be one of: 3556** <ul> 3557** <li> A database filename pointer created by the SQLite core and 3558** passed into the xOpen() method of a VFS implemention, or 3559** <li> A filename obtained from [sqlite3_db_filename()], or 3560** <li> A new filename constructed using [sqlite3_create_filename()]. 3561** </ul> 3562** If the F parameter is not one of the above, then the behavior is 3563** undefined and probably undesirable. Older versions of SQLite were 3564** more tolerant of invalid F parameters than newer versions. 3565** 3566** If F is a suitable filename (as described in the previous paragraph) 3567** and if P is the name of the query parameter, then 3568** sqlite3_uri_parameter(F,P) returns the value of the P 3569** parameter if it exists or a NULL pointer if P does not appear as a 3570** query parameter on F. If P is a query parameter of F and it 3571** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3572** a pointer to an empty string. 3573** 3574** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3575** parameter and returns true (1) or false (0) according to the value 3576** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3577** value of query parameter P is one of "yes", "true", or "on" in any 3578** case or if the value begins with a non-zero number. The 3579** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3580** query parameter P is one of "no", "false", or "off" in any case or 3581** if the value begins with a numeric zero. If P is not a query 3582** parameter on F or if the value of P does not match any of the 3583** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3584** 3585** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3586** 64-bit signed integer and returns that integer, or D if P does not 3587** exist. If the value of P is something other than an integer, then 3588** zero is returned. 3589** 3590** The sqlite3_uri_key(F,N) returns a pointer to the name (not 3591** the value) of the N-th query parameter for filename F, or a NULL 3592** pointer if N is less than zero or greater than the number of query 3593** parameters minus 1. The N value is zero-based so N should be 0 to obtain 3594** the name of the first query parameter, 1 for the second parameter, and 3595** so forth. 3596** 3597** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3598** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3599** is not a database file pathname pointer that the SQLite core passed 3600** into the xOpen VFS method, then the behavior of this routine is undefined 3601** and probably undesirable. 3602** 3603** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F 3604** parameter can also be the name of a rollback journal file or WAL file 3605** in addition to the main database file. Prior to version 3.31.0, these 3606** routines would only work if F was the name of the main database file. 3607** When the F parameter is the name of the rollback journal or WAL file, 3608** it has access to all the same query parameters as were found on the 3609** main database file. 3610** 3611** See the [URI filename] documentation for additional information. 3612*/ 3613const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3614int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3615sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3616const char *sqlite3_uri_key(const char *zFilename, int N); 3617 3618/* 3619** CAPI3REF: Translate filenames 3620** 3621** These routines are available to [VFS|custom VFS implementations] for 3622** translating filenames between the main database file, the journal file, 3623** and the WAL file. 3624** 3625** If F is the name of an sqlite database file, journal file, or WAL file 3626** passed by the SQLite core into the VFS, then sqlite3_filename_database(F) 3627** returns the name of the corresponding database file. 3628** 3629** If F is the name of an sqlite database file, journal file, or WAL file 3630** passed by the SQLite core into the VFS, or if F is a database filename 3631** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F) 3632** returns the name of the corresponding rollback journal file. 3633** 3634** If F is the name of an sqlite database file, journal file, or WAL file 3635** that was passed by the SQLite core into the VFS, or if F is a database 3636** filename obtained from [sqlite3_db_filename()], then 3637** sqlite3_filename_wal(F) returns the name of the corresponding 3638** WAL file. 3639** 3640** In all of the above, if F is not the name of a database, journal or WAL 3641** filename passed into the VFS from the SQLite core and F is not the 3642** return value from [sqlite3_db_filename()], then the result is 3643** undefined and is likely a memory access violation. 3644*/ 3645const char *sqlite3_filename_database(const char*); 3646const char *sqlite3_filename_journal(const char*); 3647const char *sqlite3_filename_wal(const char*); 3648 3649/* 3650** CAPI3REF: Database File Corresponding To A Journal 3651** 3652** ^If X is the name of a rollback or WAL-mode journal file that is 3653** passed into the xOpen method of [sqlite3_vfs], then 3654** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file] 3655** object that represents the main database file. 3656** 3657** This routine is intended for use in custom [VFS] implementations 3658** only. It is not a general-purpose interface. 3659** The argument sqlite3_file_object(X) must be a filename pointer that 3660** has been passed into [sqlite3_vfs].xOpen method where the 3661** flags parameter to xOpen contains one of the bits 3662** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL]. Any other use 3663** of this routine results in undefined and probably undesirable 3664** behavior. 3665*/ 3666sqlite3_file *sqlite3_database_file_object(const char*); 3667 3668/* 3669** CAPI3REF: Create and Destroy VFS Filenames 3670** 3671** These interfces are provided for use by [VFS shim] implementations and 3672** are not useful outside of that context. 3673** 3674** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of 3675** database filename D with corresponding journal file J and WAL file W and 3676** with N URI parameters key/values pairs in the array P. The result from 3677** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that 3678** is safe to pass to routines like: 3679** <ul> 3680** <li> [sqlite3_uri_parameter()], 3681** <li> [sqlite3_uri_boolean()], 3682** <li> [sqlite3_uri_int64()], 3683** <li> [sqlite3_uri_key()], 3684** <li> [sqlite3_filename_database()], 3685** <li> [sqlite3_filename_journal()], or 3686** <li> [sqlite3_filename_wal()]. 3687** </ul> 3688** If a memory allocation error occurs, sqlite3_create_filename() might 3689** return a NULL pointer. The memory obtained from sqlite3_create_filename(X) 3690** must be released by a corresponding call to sqlite3_free_filename(Y). 3691** 3692** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array 3693** of 2*N pointers to strings. Each pair of pointers in this array corresponds 3694** to a key and value for a query parameter. The P parameter may be a NULL 3695** pointer if N is zero. None of the 2*N pointers in the P array may be 3696** NULL pointers and key pointers should not be empty strings. 3697** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may 3698** be NULL pointers, though they can be empty strings. 3699** 3700** The sqlite3_free_filename(Y) routine releases a memory allocation 3701** previously obtained from sqlite3_create_filename(). Invoking 3702** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op. 3703** 3704** If the Y parameter to sqlite3_free_filename(Y) is anything other 3705** than a NULL pointer or a pointer previously acquired from 3706** sqlite3_create_filename(), then bad things such as heap 3707** corruption or segfaults may occur. The value Y should not be 3708** used again after sqlite3_free_filename(Y) has been called. This means 3709** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y, 3710** then the corresponding [sqlite3_module.xClose() method should also be 3711** invoked prior to calling sqlite3_free_filename(Y). 3712*/ 3713char *sqlite3_create_filename( 3714 const char *zDatabase, 3715 const char *zJournal, 3716 const char *zWal, 3717 int nParam, 3718 const char **azParam 3719); 3720void sqlite3_free_filename(char*); 3721 3722/* 3723** CAPI3REF: Error Codes And Messages 3724** METHOD: sqlite3 3725** 3726** ^If the most recent sqlite3_* API call associated with 3727** [database connection] D failed, then the sqlite3_errcode(D) interface 3728** returns the numeric [result code] or [extended result code] for that 3729** API call. 3730** ^The sqlite3_extended_errcode() 3731** interface is the same except that it always returns the 3732** [extended result code] even when extended result codes are 3733** disabled. 3734** 3735** The values returned by sqlite3_errcode() and/or 3736** sqlite3_extended_errcode() might change with each API call. 3737** Except, there are some interfaces that are guaranteed to never 3738** change the value of the error code. The error-code preserving 3739** interfaces are: 3740** 3741** <ul> 3742** <li> sqlite3_errcode() 3743** <li> sqlite3_extended_errcode() 3744** <li> sqlite3_errmsg() 3745** <li> sqlite3_errmsg16() 3746** </ul> 3747** 3748** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3749** text that describes the error, as either UTF-8 or UTF-16 respectively. 3750** ^(Memory to hold the error message string is managed internally. 3751** The application does not need to worry about freeing the result. 3752** However, the error string might be overwritten or deallocated by 3753** subsequent calls to other SQLite interface functions.)^ 3754** 3755** ^The sqlite3_errstr() interface returns the English-language text 3756** that describes the [result code], as UTF-8. 3757** ^(Memory to hold the error message string is managed internally 3758** and must not be freed by the application)^. 3759** 3760** When the serialized [threading mode] is in use, it might be the 3761** case that a second error occurs on a separate thread in between 3762** the time of the first error and the call to these interfaces. 3763** When that happens, the second error will be reported since these 3764** interfaces always report the most recent result. To avoid 3765** this, each thread can obtain exclusive use of the [database connection] D 3766** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3767** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3768** all calls to the interfaces listed here are completed. 3769** 3770** If an interface fails with SQLITE_MISUSE, that means the interface 3771** was invoked incorrectly by the application. In that case, the 3772** error code and message may or may not be set. 3773*/ 3774int sqlite3_errcode(sqlite3 *db); 3775int sqlite3_extended_errcode(sqlite3 *db); 3776const char *sqlite3_errmsg(sqlite3*); 3777const void *sqlite3_errmsg16(sqlite3*); 3778const char *sqlite3_errstr(int); 3779 3780/* 3781** CAPI3REF: Prepared Statement Object 3782** KEYWORDS: {prepared statement} {prepared statements} 3783** 3784** An instance of this object represents a single SQL statement that 3785** has been compiled into binary form and is ready to be evaluated. 3786** 3787** Think of each SQL statement as a separate computer program. The 3788** original SQL text is source code. A prepared statement object 3789** is the compiled object code. All SQL must be converted into a 3790** prepared statement before it can be run. 3791** 3792** The life-cycle of a prepared statement object usually goes like this: 3793** 3794** <ol> 3795** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3796** <li> Bind values to [parameters] using the sqlite3_bind_*() 3797** interfaces. 3798** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3799** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3800** to step 2. Do this zero or more times. 3801** <li> Destroy the object using [sqlite3_finalize()]. 3802** </ol> 3803*/ 3804typedef struct sqlite3_stmt sqlite3_stmt; 3805 3806/* 3807** CAPI3REF: Run-time Limits 3808** METHOD: sqlite3 3809** 3810** ^(This interface allows the size of various constructs to be limited 3811** on a connection by connection basis. The first parameter is the 3812** [database connection] whose limit is to be set or queried. The 3813** second parameter is one of the [limit categories] that define a 3814** class of constructs to be size limited. The third parameter is the 3815** new limit for that construct.)^ 3816** 3817** ^If the new limit is a negative number, the limit is unchanged. 3818** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3819** [limits | hard upper bound] 3820** set at compile-time by a C preprocessor macro called 3821** [limits | SQLITE_MAX_<i>NAME</i>]. 3822** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3823** ^Attempts to increase a limit above its hard upper bound are 3824** silently truncated to the hard upper bound. 3825** 3826** ^Regardless of whether or not the limit was changed, the 3827** [sqlite3_limit()] interface returns the prior value of the limit. 3828** ^Hence, to find the current value of a limit without changing it, 3829** simply invoke this interface with the third parameter set to -1. 3830** 3831** Run-time limits are intended for use in applications that manage 3832** both their own internal database and also databases that are controlled 3833** by untrusted external sources. An example application might be a 3834** web browser that has its own databases for storing history and 3835** separate databases controlled by JavaScript applications downloaded 3836** off the Internet. The internal databases can be given the 3837** large, default limits. Databases managed by external sources can 3838** be given much smaller limits designed to prevent a denial of service 3839** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3840** interface to further control untrusted SQL. The size of the database 3841** created by an untrusted script can be contained using the 3842** [max_page_count] [PRAGMA]. 3843** 3844** New run-time limit categories may be added in future releases. 3845*/ 3846int sqlite3_limit(sqlite3*, int id, int newVal); 3847 3848/* 3849** CAPI3REF: Run-Time Limit Categories 3850** KEYWORDS: {limit category} {*limit categories} 3851** 3852** These constants define various performance limits 3853** that can be lowered at run-time using [sqlite3_limit()]. 3854** The synopsis of the meanings of the various limits is shown below. 3855** Additional information is available at [limits | Limits in SQLite]. 3856** 3857** <dl> 3858** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3859** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3860** 3861** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3862** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3863** 3864** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3865** <dd>The maximum number of columns in a table definition or in the 3866** result set of a [SELECT] or the maximum number of columns in an index 3867** or in an ORDER BY or GROUP BY clause.</dd>)^ 3868** 3869** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3870** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3871** 3872** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3873** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3874** 3875** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3876** <dd>The maximum number of instructions in a virtual machine program 3877** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3878** the equivalent tries to allocate space for more than this many opcodes 3879** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3880** 3881** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3882** <dd>The maximum number of arguments on a function.</dd>)^ 3883** 3884** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3885** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3886** 3887** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3888** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3889** <dd>The maximum length of the pattern argument to the [LIKE] or 3890** [GLOB] operators.</dd>)^ 3891** 3892** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3893** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3894** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3895** 3896** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3897** <dd>The maximum depth of recursion for triggers.</dd>)^ 3898** 3899** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3900** <dd>The maximum number of auxiliary worker threads that a single 3901** [prepared statement] may start.</dd>)^ 3902** </dl> 3903*/ 3904#define SQLITE_LIMIT_LENGTH 0 3905#define SQLITE_LIMIT_SQL_LENGTH 1 3906#define SQLITE_LIMIT_COLUMN 2 3907#define SQLITE_LIMIT_EXPR_DEPTH 3 3908#define SQLITE_LIMIT_COMPOUND_SELECT 4 3909#define SQLITE_LIMIT_VDBE_OP 5 3910#define SQLITE_LIMIT_FUNCTION_ARG 6 3911#define SQLITE_LIMIT_ATTACHED 7 3912#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3913#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3914#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3915#define SQLITE_LIMIT_WORKER_THREADS 11 3916 3917/* 3918** CAPI3REF: Prepare Flags 3919** 3920** These constants define various flags that can be passed into 3921** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3922** [sqlite3_prepare16_v3()] interfaces. 3923** 3924** New flags may be added in future releases of SQLite. 3925** 3926** <dl> 3927** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3928** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3929** that the prepared statement will be retained for a long time and 3930** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3931** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3932** be used just once or at most a few times and then destroyed using 3933** [sqlite3_finalize()] relatively soon. The current implementation acts 3934** on this hint by avoiding the use of [lookaside memory] so as not to 3935** deplete the limited store of lookaside memory. Future versions of 3936** SQLite may act on this hint differently. 3937** 3938** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt> 3939** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used 3940** to be required for any prepared statement that wanted to use the 3941** [sqlite3_normalized_sql()] interface. However, the 3942** [sqlite3_normalized_sql()] interface is now available to all 3943** prepared statements, regardless of whether or not they use this 3944** flag. 3945** 3946** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt> 3947** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler 3948** to return an error (error code SQLITE_ERROR) if the statement uses 3949** any virtual tables. 3950** </dl> 3951*/ 3952#define SQLITE_PREPARE_PERSISTENT 0x01 3953#define SQLITE_PREPARE_NORMALIZE 0x02 3954#define SQLITE_PREPARE_NO_VTAB 0x04 3955 3956/* 3957** CAPI3REF: Compiling An SQL Statement 3958** KEYWORDS: {SQL statement compiler} 3959** METHOD: sqlite3 3960** CONSTRUCTOR: sqlite3_stmt 3961** 3962** To execute an SQL statement, it must first be compiled into a byte-code 3963** program using one of these routines. Or, in other words, these routines 3964** are constructors for the [prepared statement] object. 3965** 3966** The preferred routine to use is [sqlite3_prepare_v2()]. The 3967** [sqlite3_prepare()] interface is legacy and should be avoided. 3968** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3969** for special purposes. 3970** 3971** The use of the UTF-8 interfaces is preferred, as SQLite currently 3972** does all parsing using UTF-8. The UTF-16 interfaces are provided 3973** as a convenience. The UTF-16 interfaces work by converting the 3974** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3975** 3976** The first argument, "db", is a [database connection] obtained from a 3977** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3978** [sqlite3_open16()]. The database connection must not have been closed. 3979** 3980** The second argument, "zSql", is the statement to be compiled, encoded 3981** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3982** and sqlite3_prepare_v3() 3983** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3984** and sqlite3_prepare16_v3() use UTF-16. 3985** 3986** ^If the nByte argument is negative, then zSql is read up to the 3987** first zero terminator. ^If nByte is positive, then it is the 3988** number of bytes read from zSql. ^If nByte is zero, then no prepared 3989** statement is generated. 3990** If the caller knows that the supplied string is nul-terminated, then 3991** there is a small performance advantage to passing an nByte parameter that 3992** is the number of bytes in the input string <i>including</i> 3993** the nul-terminator. 3994** 3995** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3996** past the end of the first SQL statement in zSql. These routines only 3997** compile the first statement in zSql, so *pzTail is left pointing to 3998** what remains uncompiled. 3999** 4000** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 4001** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 4002** to NULL. ^If the input text contains no SQL (if the input is an empty 4003** string or a comment) then *ppStmt is set to NULL. 4004** The calling procedure is responsible for deleting the compiled 4005** SQL statement using [sqlite3_finalize()] after it has finished with it. 4006** ppStmt may not be NULL. 4007** 4008** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 4009** otherwise an [error code] is returned. 4010** 4011** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 4012** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 4013** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 4014** are retained for backwards compatibility, but their use is discouraged. 4015** ^In the "vX" interfaces, the prepared statement 4016** that is returned (the [sqlite3_stmt] object) contains a copy of the 4017** original SQL text. This causes the [sqlite3_step()] interface to 4018** behave differently in three ways: 4019** 4020** <ol> 4021** <li> 4022** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 4023** always used to do, [sqlite3_step()] will automatically recompile the SQL 4024** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 4025** retries will occur before sqlite3_step() gives up and returns an error. 4026** </li> 4027** 4028** <li> 4029** ^When an error occurs, [sqlite3_step()] will return one of the detailed 4030** [error codes] or [extended error codes]. ^The legacy behavior was that 4031** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 4032** and the application would have to make a second call to [sqlite3_reset()] 4033** in order to find the underlying cause of the problem. With the "v2" prepare 4034** interfaces, the underlying reason for the error is returned immediately. 4035** </li> 4036** 4037** <li> 4038** ^If the specific value bound to a [parameter | host parameter] in the 4039** WHERE clause might influence the choice of query plan for a statement, 4040** then the statement will be automatically recompiled, as if there had been 4041** a schema change, on the first [sqlite3_step()] call following any change 4042** to the [sqlite3_bind_text | bindings] of that [parameter]. 4043** ^The specific value of a WHERE-clause [parameter] might influence the 4044** choice of query plan if the parameter is the left-hand side of a [LIKE] 4045** or [GLOB] operator or if the parameter is compared to an indexed column 4046** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled. 4047** </li> 4048** </ol> 4049** 4050** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 4051** the extra prepFlags parameter, which is a bit array consisting of zero or 4052** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 4053** sqlite3_prepare_v2() interface works exactly the same as 4054** sqlite3_prepare_v3() with a zero prepFlags parameter. 4055*/ 4056int sqlite3_prepare( 4057 sqlite3 *db, /* Database handle */ 4058 const char *zSql, /* SQL statement, UTF-8 encoded */ 4059 int nByte, /* Maximum length of zSql in bytes. */ 4060 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4061 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4062); 4063int sqlite3_prepare_v2( 4064 sqlite3 *db, /* Database handle */ 4065 const char *zSql, /* SQL statement, UTF-8 encoded */ 4066 int nByte, /* Maximum length of zSql in bytes. */ 4067 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4068 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4069); 4070int sqlite3_prepare_v3( 4071 sqlite3 *db, /* Database handle */ 4072 const char *zSql, /* SQL statement, UTF-8 encoded */ 4073 int nByte, /* Maximum length of zSql in bytes. */ 4074 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4075 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4076 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4077); 4078int sqlite3_prepare16( 4079 sqlite3 *db, /* Database handle */ 4080 const void *zSql, /* SQL statement, UTF-16 encoded */ 4081 int nByte, /* Maximum length of zSql in bytes. */ 4082 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4083 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4084); 4085int sqlite3_prepare16_v2( 4086 sqlite3 *db, /* Database handle */ 4087 const void *zSql, /* SQL statement, UTF-16 encoded */ 4088 int nByte, /* Maximum length of zSql in bytes. */ 4089 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4090 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4091); 4092int sqlite3_prepare16_v3( 4093 sqlite3 *db, /* Database handle */ 4094 const void *zSql, /* SQL statement, UTF-16 encoded */ 4095 int nByte, /* Maximum length of zSql in bytes. */ 4096 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4097 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4098 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4099); 4100 4101/* 4102** CAPI3REF: Retrieving Statement SQL 4103** METHOD: sqlite3_stmt 4104** 4105** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 4106** SQL text used to create [prepared statement] P if P was 4107** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 4108** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4109** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 4110** string containing the SQL text of prepared statement P with 4111** [bound parameters] expanded. 4112** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8 4113** string containing the normalized SQL text of prepared statement P. The 4114** semantics used to normalize a SQL statement are unspecified and subject 4115** to change. At a minimum, literal values will be replaced with suitable 4116** placeholders. 4117** 4118** ^(For example, if a prepared statement is created using the SQL 4119** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 4120** and parameter :xyz is unbound, then sqlite3_sql() will return 4121** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 4122** will return "SELECT 2345,NULL".)^ 4123** 4124** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 4125** is available to hold the result, or if the result would exceed the 4126** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 4127** 4128** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 4129** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 4130** option causes sqlite3_expanded_sql() to always return NULL. 4131** 4132** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P) 4133** are managed by SQLite and are automatically freed when the prepared 4134** statement is finalized. 4135** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 4136** is obtained from [sqlite3_malloc()] and must be free by the application 4137** by passing it to [sqlite3_free()]. 4138*/ 4139const char *sqlite3_sql(sqlite3_stmt *pStmt); 4140char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 4141const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt); 4142 4143/* 4144** CAPI3REF: Determine If An SQL Statement Writes The Database 4145** METHOD: sqlite3_stmt 4146** 4147** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 4148** and only if the [prepared statement] X makes no direct changes to 4149** the content of the database file. 4150** 4151** Note that [application-defined SQL functions] or 4152** [virtual tables] might change the database indirectly as a side effect. 4153** ^(For example, if an application defines a function "eval()" that 4154** calls [sqlite3_exec()], then the following SQL statement would 4155** change the database file through side-effects: 4156** 4157** <blockquote><pre> 4158** SELECT eval('DELETE FROM t1') FROM t2; 4159** </pre></blockquote> 4160** 4161** But because the [SELECT] statement does not change the database file 4162** directly, sqlite3_stmt_readonly() would still return true.)^ 4163** 4164** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 4165** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 4166** since the statements themselves do not actually modify the database but 4167** rather they control the timing of when other statements modify the 4168** database. ^The [ATTACH] and [DETACH] statements also cause 4169** sqlite3_stmt_readonly() to return true since, while those statements 4170** change the configuration of a database connection, they do not make 4171** changes to the content of the database files on disk. 4172** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 4173** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 4174** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 4175** sqlite3_stmt_readonly() returns false for those commands. 4176*/ 4177int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 4178 4179/* 4180** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement 4181** METHOD: sqlite3_stmt 4182** 4183** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the 4184** prepared statement S is an EXPLAIN statement, or 2 if the 4185** statement S is an EXPLAIN QUERY PLAN. 4186** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is 4187** an ordinary statement or a NULL pointer. 4188*/ 4189int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt); 4190 4191/* 4192** CAPI3REF: Determine If A Prepared Statement Has Been Reset 4193** METHOD: sqlite3_stmt 4194** 4195** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 4196** [prepared statement] S has been stepped at least once using 4197** [sqlite3_step(S)] but has neither run to completion (returned 4198** [SQLITE_DONE] from [sqlite3_step(S)]) nor 4199** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 4200** interface returns false if S is a NULL pointer. If S is not a 4201** NULL pointer and is not a pointer to a valid [prepared statement] 4202** object, then the behavior is undefined and probably undesirable. 4203** 4204** This interface can be used in combination [sqlite3_next_stmt()] 4205** to locate all prepared statements associated with a database 4206** connection that are in need of being reset. This can be used, 4207** for example, in diagnostic routines to search for prepared 4208** statements that are holding a transaction open. 4209*/ 4210int sqlite3_stmt_busy(sqlite3_stmt*); 4211 4212/* 4213** CAPI3REF: Dynamically Typed Value Object 4214** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 4215** 4216** SQLite uses the sqlite3_value object to represent all values 4217** that can be stored in a database table. SQLite uses dynamic typing 4218** for the values it stores. ^Values stored in sqlite3_value objects 4219** can be integers, floating point values, strings, BLOBs, or NULL. 4220** 4221** An sqlite3_value object may be either "protected" or "unprotected". 4222** Some interfaces require a protected sqlite3_value. Other interfaces 4223** will accept either a protected or an unprotected sqlite3_value. 4224** Every interface that accepts sqlite3_value arguments specifies 4225** whether or not it requires a protected sqlite3_value. The 4226** [sqlite3_value_dup()] interface can be used to construct a new 4227** protected sqlite3_value from an unprotected sqlite3_value. 4228** 4229** The terms "protected" and "unprotected" refer to whether or not 4230** a mutex is held. An internal mutex is held for a protected 4231** sqlite3_value object but no mutex is held for an unprotected 4232** sqlite3_value object. If SQLite is compiled to be single-threaded 4233** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 4234** or if SQLite is run in one of reduced mutex modes 4235** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 4236** then there is no distinction between protected and unprotected 4237** sqlite3_value objects and they can be used interchangeably. However, 4238** for maximum code portability it is recommended that applications 4239** still make the distinction between protected and unprotected 4240** sqlite3_value objects even when not strictly required. 4241** 4242** ^The sqlite3_value objects that are passed as parameters into the 4243** implementation of [application-defined SQL functions] are protected. 4244** ^The sqlite3_value object returned by 4245** [sqlite3_column_value()] is unprotected. 4246** Unprotected sqlite3_value objects may only be used as arguments 4247** to [sqlite3_result_value()], [sqlite3_bind_value()], and 4248** [sqlite3_value_dup()]. 4249** The [sqlite3_value_blob | sqlite3_value_type()] family of 4250** interfaces require protected sqlite3_value objects. 4251*/ 4252typedef struct sqlite3_value sqlite3_value; 4253 4254/* 4255** CAPI3REF: SQL Function Context Object 4256** 4257** The context in which an SQL function executes is stored in an 4258** sqlite3_context object. ^A pointer to an sqlite3_context object 4259** is always first parameter to [application-defined SQL functions]. 4260** The application-defined SQL function implementation will pass this 4261** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 4262** [sqlite3_aggregate_context()], [sqlite3_user_data()], 4263** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 4264** and/or [sqlite3_set_auxdata()]. 4265*/ 4266typedef struct sqlite3_context sqlite3_context; 4267 4268/* 4269** CAPI3REF: Binding Values To Prepared Statements 4270** KEYWORDS: {host parameter} {host parameters} {host parameter name} 4271** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 4272** METHOD: sqlite3_stmt 4273** 4274** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 4275** literals may be replaced by a [parameter] that matches one of following 4276** templates: 4277** 4278** <ul> 4279** <li> ? 4280** <li> ?NNN 4281** <li> :VVV 4282** <li> @VVV 4283** <li> $VVV 4284** </ul> 4285** 4286** In the templates above, NNN represents an integer literal, 4287** and VVV represents an alphanumeric identifier.)^ ^The values of these 4288** parameters (also called "host parameter names" or "SQL parameters") 4289** can be set using the sqlite3_bind_*() routines defined here. 4290** 4291** ^The first argument to the sqlite3_bind_*() routines is always 4292** a pointer to the [sqlite3_stmt] object returned from 4293** [sqlite3_prepare_v2()] or its variants. 4294** 4295** ^The second argument is the index of the SQL parameter to be set. 4296** ^The leftmost SQL parameter has an index of 1. ^When the same named 4297** SQL parameter is used more than once, second and subsequent 4298** occurrences have the same index as the first occurrence. 4299** ^The index for named parameters can be looked up using the 4300** [sqlite3_bind_parameter_index()] API if desired. ^The index 4301** for "?NNN" parameters is the value of NNN. 4302** ^The NNN value must be between 1 and the [sqlite3_limit()] 4303** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766). 4304** 4305** ^The third argument is the value to bind to the parameter. 4306** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4307** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 4308** is ignored and the end result is the same as sqlite3_bind_null(). 4309** ^If the third parameter to sqlite3_bind_text() is not NULL, then 4310** it should be a pointer to well-formed UTF8 text. 4311** ^If the third parameter to sqlite3_bind_text16() is not NULL, then 4312** it should be a pointer to well-formed UTF16 text. 4313** ^If the third parameter to sqlite3_bind_text64() is not NULL, then 4314** it should be a pointer to a well-formed unicode string that is 4315** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16 4316** otherwise. 4317** 4318** [[byte-order determination rules]] ^The byte-order of 4319** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF) 4320** found in first character, which is removed, or in the absence of a BOM 4321** the byte order is the native byte order of the host 4322** machine for sqlite3_bind_text16() or the byte order specified in 4323** the 6th parameter for sqlite3_bind_text64().)^ 4324** ^If UTF16 input text contains invalid unicode 4325** characters, then SQLite might change those invalid characters 4326** into the unicode replacement character: U+FFFD. 4327** 4328** ^(In those routines that have a fourth argument, its value is the 4329** number of bytes in the parameter. To be clear: the value is the 4330** number of <u>bytes</u> in the value, not the number of characters.)^ 4331** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4332** is negative, then the length of the string is 4333** the number of bytes up to the first zero terminator. 4334** If the fourth parameter to sqlite3_bind_blob() is negative, then 4335** the behavior is undefined. 4336** If a non-negative fourth parameter is provided to sqlite3_bind_text() 4337** or sqlite3_bind_text16() or sqlite3_bind_text64() then 4338** that parameter must be the byte offset 4339** where the NUL terminator would occur assuming the string were NUL 4340** terminated. If any NUL characters occurs at byte offsets less than 4341** the value of the fourth parameter then the resulting string value will 4342** contain embedded NULs. The result of expressions involving strings 4343** with embedded NULs is undefined. 4344** 4345** ^The fifth argument to the BLOB and string binding interfaces 4346** is a destructor used to dispose of the BLOB or 4347** string after SQLite has finished with it. ^The destructor is called 4348** to dispose of the BLOB or string even if the call to the bind API fails, 4349** except the destructor is not called if the third parameter is a NULL 4350** pointer or the fourth parameter is negative. 4351** ^If the fifth argument is 4352** the special value [SQLITE_STATIC], then SQLite assumes that the 4353** information is in static, unmanaged space and does not need to be freed. 4354** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 4355** SQLite makes its own private copy of the data immediately, before 4356** the sqlite3_bind_*() routine returns. 4357** 4358** ^The sixth argument to sqlite3_bind_text64() must be one of 4359** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 4360** to specify the encoding of the text in the third parameter. If 4361** the sixth argument to sqlite3_bind_text64() is not one of the 4362** allowed values shown above, or if the text encoding is different 4363** from the encoding specified by the sixth parameter, then the behavior 4364** is undefined. 4365** 4366** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 4367** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 4368** (just an integer to hold its size) while it is being processed. 4369** Zeroblobs are intended to serve as placeholders for BLOBs whose 4370** content is later written using 4371** [sqlite3_blob_open | incremental BLOB I/O] routines. 4372** ^A negative value for the zeroblob results in a zero-length BLOB. 4373** 4374** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 4375** [prepared statement] S to have an SQL value of NULL, but to also be 4376** associated with the pointer P of type T. ^D is either a NULL pointer or 4377** a pointer to a destructor function for P. ^SQLite will invoke the 4378** destructor D with a single argument of P when it is finished using 4379** P. The T parameter should be a static string, preferably a string 4380** literal. The sqlite3_bind_pointer() routine is part of the 4381** [pointer passing interface] added for SQLite 3.20.0. 4382** 4383** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 4384** for the [prepared statement] or with a prepared statement for which 4385** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 4386** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 4387** routine is passed a [prepared statement] that has been finalized, the 4388** result is undefined and probably harmful. 4389** 4390** ^Bindings are not cleared by the [sqlite3_reset()] routine. 4391** ^Unbound parameters are interpreted as NULL. 4392** 4393** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 4394** [error code] if anything goes wrong. 4395** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 4396** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 4397** [SQLITE_MAX_LENGTH]. 4398** ^[SQLITE_RANGE] is returned if the parameter 4399** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 4400** 4401** See also: [sqlite3_bind_parameter_count()], 4402** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 4403*/ 4404int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 4405int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 4406 void(*)(void*)); 4407int sqlite3_bind_double(sqlite3_stmt*, int, double); 4408int sqlite3_bind_int(sqlite3_stmt*, int, int); 4409int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 4410int sqlite3_bind_null(sqlite3_stmt*, int); 4411int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 4412int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 4413int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 4414 void(*)(void*), unsigned char encoding); 4415int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 4416int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 4417int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 4418int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 4419 4420/* 4421** CAPI3REF: Number Of SQL Parameters 4422** METHOD: sqlite3_stmt 4423** 4424** ^This routine can be used to find the number of [SQL parameters] 4425** in a [prepared statement]. SQL parameters are tokens of the 4426** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4427** placeholders for values that are [sqlite3_bind_blob | bound] 4428** to the parameters at a later time. 4429** 4430** ^(This routine actually returns the index of the largest (rightmost) 4431** parameter. For all forms except ?NNN, this will correspond to the 4432** number of unique parameters. If parameters of the ?NNN form are used, 4433** there may be gaps in the list.)^ 4434** 4435** See also: [sqlite3_bind_blob|sqlite3_bind()], 4436** [sqlite3_bind_parameter_name()], and 4437** [sqlite3_bind_parameter_index()]. 4438*/ 4439int sqlite3_bind_parameter_count(sqlite3_stmt*); 4440 4441/* 4442** CAPI3REF: Name Of A Host Parameter 4443** METHOD: sqlite3_stmt 4444** 4445** ^The sqlite3_bind_parameter_name(P,N) interface returns 4446** the name of the N-th [SQL parameter] in the [prepared statement] P. 4447** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4448** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4449** respectively. 4450** In other words, the initial ":" or "$" or "@" or "?" 4451** is included as part of the name.)^ 4452** ^Parameters of the form "?" without a following integer have no name 4453** and are referred to as "nameless" or "anonymous parameters". 4454** 4455** ^The first host parameter has an index of 1, not 0. 4456** 4457** ^If the value N is out of range or if the N-th parameter is 4458** nameless, then NULL is returned. ^The returned string is 4459** always in UTF-8 encoding even if the named parameter was 4460** originally specified as UTF-16 in [sqlite3_prepare16()], 4461** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4462** 4463** See also: [sqlite3_bind_blob|sqlite3_bind()], 4464** [sqlite3_bind_parameter_count()], and 4465** [sqlite3_bind_parameter_index()]. 4466*/ 4467const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4468 4469/* 4470** CAPI3REF: Index Of A Parameter With A Given Name 4471** METHOD: sqlite3_stmt 4472** 4473** ^Return the index of an SQL parameter given its name. ^The 4474** index value returned is suitable for use as the second 4475** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4476** is returned if no matching parameter is found. ^The parameter 4477** name must be given in UTF-8 even if the original statement 4478** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4479** [sqlite3_prepare16_v3()]. 4480** 4481** See also: [sqlite3_bind_blob|sqlite3_bind()], 4482** [sqlite3_bind_parameter_count()], and 4483** [sqlite3_bind_parameter_name()]. 4484*/ 4485int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4486 4487/* 4488** CAPI3REF: Reset All Bindings On A Prepared Statement 4489** METHOD: sqlite3_stmt 4490** 4491** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4492** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4493** ^Use this routine to reset all host parameters to NULL. 4494*/ 4495int sqlite3_clear_bindings(sqlite3_stmt*); 4496 4497/* 4498** CAPI3REF: Number Of Columns In A Result Set 4499** METHOD: sqlite3_stmt 4500** 4501** ^Return the number of columns in the result set returned by the 4502** [prepared statement]. ^If this routine returns 0, that means the 4503** [prepared statement] returns no data (for example an [UPDATE]). 4504** ^However, just because this routine returns a positive number does not 4505** mean that one or more rows of data will be returned. ^A SELECT statement 4506** will always have a positive sqlite3_column_count() but depending on the 4507** WHERE clause constraints and the table content, it might return no rows. 4508** 4509** See also: [sqlite3_data_count()] 4510*/ 4511int sqlite3_column_count(sqlite3_stmt *pStmt); 4512 4513/* 4514** CAPI3REF: Column Names In A Result Set 4515** METHOD: sqlite3_stmt 4516** 4517** ^These routines return the name assigned to a particular column 4518** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4519** interface returns a pointer to a zero-terminated UTF-8 string 4520** and sqlite3_column_name16() returns a pointer to a zero-terminated 4521** UTF-16 string. ^The first parameter is the [prepared statement] 4522** that implements the [SELECT] statement. ^The second parameter is the 4523** column number. ^The leftmost column is number 0. 4524** 4525** ^The returned string pointer is valid until either the [prepared statement] 4526** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4527** reprepared by the first call to [sqlite3_step()] for a particular run 4528** or until the next call to 4529** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4530** 4531** ^If sqlite3_malloc() fails during the processing of either routine 4532** (for example during a conversion from UTF-8 to UTF-16) then a 4533** NULL pointer is returned. 4534** 4535** ^The name of a result column is the value of the "AS" clause for 4536** that column, if there is an AS clause. If there is no AS clause 4537** then the name of the column is unspecified and may change from 4538** one release of SQLite to the next. 4539*/ 4540const char *sqlite3_column_name(sqlite3_stmt*, int N); 4541const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4542 4543/* 4544** CAPI3REF: Source Of Data In A Query Result 4545** METHOD: sqlite3_stmt 4546** 4547** ^These routines provide a means to determine the database, table, and 4548** table column that is the origin of a particular result column in 4549** [SELECT] statement. 4550** ^The name of the database or table or column can be returned as 4551** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4552** the database name, the _table_ routines return the table name, and 4553** the origin_ routines return the column name. 4554** ^The returned string is valid until the [prepared statement] is destroyed 4555** using [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 same information is requested 4558** again in a different encoding. 4559** 4560** ^The names returned are the original un-aliased names of the 4561** database, table, and column. 4562** 4563** ^The first argument to these interfaces is a [prepared statement]. 4564** ^These functions return information about the Nth result column returned by 4565** the statement, where N is the second function argument. 4566** ^The left-most column is column 0 for these routines. 4567** 4568** ^If the Nth column returned by the statement is an expression or 4569** subquery and is not a column value, then all of these functions return 4570** NULL. ^These routines might also return NULL if a memory allocation error 4571** occurs. ^Otherwise, they return the name of the attached database, table, 4572** or column that query result column was extracted from. 4573** 4574** ^As with all other SQLite APIs, those whose names end with "16" return 4575** UTF-16 encoded strings and the other functions return UTF-8. 4576** 4577** ^These APIs are only available if the library was compiled with the 4578** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4579** 4580** If two or more threads call one or more 4581** [sqlite3_column_database_name | column metadata interfaces] 4582** for the same [prepared statement] and result column 4583** at the same time then the results are undefined. 4584*/ 4585const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4586const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4587const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4588const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4589const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4590const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4591 4592/* 4593** CAPI3REF: Declared Datatype Of A Query Result 4594** METHOD: sqlite3_stmt 4595** 4596** ^(The first parameter is a [prepared statement]. 4597** If this statement is a [SELECT] statement and the Nth column of the 4598** returned result set of that [SELECT] is a table column (not an 4599** expression or subquery) then the declared type of the table 4600** column is returned.)^ ^If the Nth column of the result set is an 4601** expression or subquery, then a NULL pointer is returned. 4602** ^The returned string is always UTF-8 encoded. 4603** 4604** ^(For example, given the database schema: 4605** 4606** CREATE TABLE t1(c1 VARIANT); 4607** 4608** and the following statement to be compiled: 4609** 4610** SELECT c1 + 1, c1 FROM t1; 4611** 4612** this routine would return the string "VARIANT" for the second result 4613** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4614** 4615** ^SQLite uses dynamic run-time typing. ^So just because a column 4616** is declared to contain a particular type does not mean that the 4617** data stored in that column is of the declared type. SQLite is 4618** strongly typed, but the typing is dynamic not static. ^Type 4619** is associated with individual values, not with the containers 4620** used to hold those values. 4621*/ 4622const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4623const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4624 4625/* 4626** CAPI3REF: Evaluate An SQL Statement 4627** METHOD: sqlite3_stmt 4628** 4629** After a [prepared statement] has been prepared using any of 4630** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4631** or [sqlite3_prepare16_v3()] or one of the legacy 4632** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4633** must be called one or more times to evaluate the statement. 4634** 4635** The details of the behavior of the sqlite3_step() interface depend 4636** on whether the statement was prepared using the newer "vX" interfaces 4637** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4638** [sqlite3_prepare16_v2()] or the older legacy 4639** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4640** new "vX" interface is recommended for new applications but the legacy 4641** interface will continue to be supported. 4642** 4643** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4644** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4645** ^With the "v2" interface, any of the other [result codes] or 4646** [extended result codes] might be returned as well. 4647** 4648** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4649** database locks it needs to do its job. ^If the statement is a [COMMIT] 4650** or occurs outside of an explicit transaction, then you can retry the 4651** statement. If the statement is not a [COMMIT] and occurs within an 4652** explicit transaction then you should rollback the transaction before 4653** continuing. 4654** 4655** ^[SQLITE_DONE] means that the statement has finished executing 4656** successfully. sqlite3_step() should not be called again on this virtual 4657** machine without first calling [sqlite3_reset()] to reset the virtual 4658** machine back to its initial state. 4659** 4660** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4661** is returned each time a new row of data is ready for processing by the 4662** caller. The values may be accessed using the [column access functions]. 4663** sqlite3_step() is called again to retrieve the next row of data. 4664** 4665** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4666** violation) has occurred. sqlite3_step() should not be called again on 4667** the VM. More information may be found by calling [sqlite3_errmsg()]. 4668** ^With the legacy interface, a more specific error code (for example, 4669** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4670** can be obtained by calling [sqlite3_reset()] on the 4671** [prepared statement]. ^In the "v2" interface, 4672** the more specific error code is returned directly by sqlite3_step(). 4673** 4674** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4675** Perhaps it was called on a [prepared statement] that has 4676** already been [sqlite3_finalize | finalized] or on one that had 4677** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4678** be the case that the same database connection is being used by two or 4679** more threads at the same moment in time. 4680** 4681** For all versions of SQLite up to and including 3.6.23.1, a call to 4682** [sqlite3_reset()] was required after sqlite3_step() returned anything 4683** other than [SQLITE_ROW] before any subsequent invocation of 4684** sqlite3_step(). Failure to reset the prepared statement using 4685** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4686** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4687** sqlite3_step() began 4688** calling [sqlite3_reset()] automatically in this circumstance rather 4689** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4690** break because any application that ever receives an SQLITE_MISUSE error 4691** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4692** can be used to restore the legacy behavior. 4693** 4694** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4695** API always returns a generic error code, [SQLITE_ERROR], following any 4696** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4697** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4698** specific [error codes] that better describes the error. 4699** We admit that this is a goofy design. The problem has been fixed 4700** with the "v2" interface. If you prepare all of your SQL statements 4701** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4702** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4703** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4704** then the more specific [error codes] are returned directly 4705** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4706*/ 4707int sqlite3_step(sqlite3_stmt*); 4708 4709/* 4710** CAPI3REF: Number of columns in a result set 4711** METHOD: sqlite3_stmt 4712** 4713** ^The sqlite3_data_count(P) interface returns the number of columns in the 4714** current row of the result set of [prepared statement] P. 4715** ^If prepared statement P does not have results ready to return 4716** (via calls to the [sqlite3_column_int | sqlite3_column()] family of 4717** interfaces) then sqlite3_data_count(P) returns 0. 4718** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4719** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4720** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4721** will return non-zero if previous call to [sqlite3_step](P) returned 4722** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4723** where it always returns zero since each step of that multi-step 4724** pragma returns 0 columns of data. 4725** 4726** See also: [sqlite3_column_count()] 4727*/ 4728int sqlite3_data_count(sqlite3_stmt *pStmt); 4729 4730/* 4731** CAPI3REF: Fundamental Datatypes 4732** KEYWORDS: SQLITE_TEXT 4733** 4734** ^(Every value in SQLite has one of five fundamental datatypes: 4735** 4736** <ul> 4737** <li> 64-bit signed integer 4738** <li> 64-bit IEEE floating point number 4739** <li> string 4740** <li> BLOB 4741** <li> NULL 4742** </ul>)^ 4743** 4744** These constants are codes for each of those types. 4745** 4746** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4747** for a completely different meaning. Software that links against both 4748** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4749** SQLITE_TEXT. 4750*/ 4751#define SQLITE_INTEGER 1 4752#define SQLITE_FLOAT 2 4753#define SQLITE_BLOB 4 4754#define SQLITE_NULL 5 4755#ifdef SQLITE_TEXT 4756# undef SQLITE_TEXT 4757#else 4758# define SQLITE_TEXT 3 4759#endif 4760#define SQLITE3_TEXT 3 4761 4762/* 4763** CAPI3REF: Result Values From A Query 4764** KEYWORDS: {column access functions} 4765** METHOD: sqlite3_stmt 4766** 4767** <b>Summary:</b> 4768** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4769** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4770** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4771** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4772** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4773** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4774** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4775** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4776** [sqlite3_value|unprotected sqlite3_value] object. 4777** <tr><td> <td> <td> 4778** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4779** or a UTF-8 TEXT result in bytes 4780** <tr><td><b>sqlite3_column_bytes16 </b> 4781** <td>→ <td>Size of UTF-16 4782** TEXT in bytes 4783** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4784** datatype of the result 4785** </table></blockquote> 4786** 4787** <b>Details:</b> 4788** 4789** ^These routines return information about a single column of the current 4790** result row of a query. ^In every case the first argument is a pointer 4791** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4792** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4793** and the second argument is the index of the column for which information 4794** should be returned. ^The leftmost column of the result set has the index 0. 4795** ^The number of columns in the result can be determined using 4796** [sqlite3_column_count()]. 4797** 4798** If the SQL statement does not currently point to a valid row, or if the 4799** column index is out of range, the result is undefined. 4800** These routines may only be called when the most recent call to 4801** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4802** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4803** If any of these routines are called after [sqlite3_reset()] or 4804** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4805** something other than [SQLITE_ROW], the results are undefined. 4806** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4807** are called from a different thread while any of these routines 4808** are pending, then the results are undefined. 4809** 4810** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4811** each return the value of a result column in a specific data format. If 4812** the result column is not initially in the requested format (for example, 4813** if the query returns an integer but the sqlite3_column_text() interface 4814** is used to extract the value) then an automatic type conversion is performed. 4815** 4816** ^The sqlite3_column_type() routine returns the 4817** [SQLITE_INTEGER | datatype code] for the initial data type 4818** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4819** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4820** The return value of sqlite3_column_type() can be used to decide which 4821** of the first six interface should be used to extract the column value. 4822** The value returned by sqlite3_column_type() is only meaningful if no 4823** automatic type conversions have occurred for the value in question. 4824** After a type conversion, the result of calling sqlite3_column_type() 4825** is undefined, though harmless. Future 4826** versions of SQLite may change the behavior of sqlite3_column_type() 4827** following a type conversion. 4828** 4829** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4830** or sqlite3_column_bytes16() interfaces can be used to determine the size 4831** of that BLOB or string. 4832** 4833** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4834** routine returns the number of bytes in that BLOB or string. 4835** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4836** the string to UTF-8 and then returns the number of bytes. 4837** ^If the result is a numeric value then sqlite3_column_bytes() uses 4838** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4839** the number of bytes in that string. 4840** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4841** 4842** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4843** routine returns the number of bytes in that BLOB or string. 4844** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4845** the string to UTF-16 and then returns the number of bytes. 4846** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4847** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4848** the number of bytes in that string. 4849** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4850** 4851** ^The values returned by [sqlite3_column_bytes()] and 4852** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4853** of the string. ^For clarity: the values returned by 4854** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4855** bytes in the string, not the number of characters. 4856** 4857** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4858** even empty strings, are always zero-terminated. ^The return 4859** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4860** 4861** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4862** [unprotected sqlite3_value] object. In a multithreaded environment, 4863** an unprotected sqlite3_value object may only be used safely with 4864** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4865** If the [unprotected sqlite3_value] object returned by 4866** [sqlite3_column_value()] is used in any other way, including calls 4867** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4868** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4869** Hence, the sqlite3_column_value() interface 4870** is normally only useful within the implementation of 4871** [application-defined SQL functions] or [virtual tables], not within 4872** top-level application code. 4873** 4874** The these routines may attempt to convert the datatype of the result. 4875** ^For example, if the internal representation is FLOAT and a text result 4876** is requested, [sqlite3_snprintf()] is used internally to perform the 4877** conversion automatically. ^(The following table details the conversions 4878** that are applied: 4879** 4880** <blockquote> 4881** <table border="1"> 4882** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4883** 4884** <tr><td> NULL <td> INTEGER <td> Result is 0 4885** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4886** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4887** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4888** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4889** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4890** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4891** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4892** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4893** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4894** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4895** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4896** <tr><td> TEXT <td> BLOB <td> No change 4897** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4898** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4899** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4900** </table> 4901** </blockquote>)^ 4902** 4903** Note that when type conversions occur, pointers returned by prior 4904** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4905** sqlite3_column_text16() may be invalidated. 4906** Type conversions and pointer invalidations might occur 4907** in the following cases: 4908** 4909** <ul> 4910** <li> The initial content is a BLOB and sqlite3_column_text() or 4911** sqlite3_column_text16() is called. A zero-terminator might 4912** need to be added to the string.</li> 4913** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4914** sqlite3_column_text16() is called. The content must be converted 4915** to UTF-16.</li> 4916** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4917** sqlite3_column_text() is called. The content must be converted 4918** to UTF-8.</li> 4919** </ul> 4920** 4921** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4922** not invalidate a prior pointer, though of course the content of the buffer 4923** that the prior pointer references will have been modified. Other kinds 4924** of conversion are done in place when it is possible, but sometimes they 4925** are not possible and in those cases prior pointers are invalidated. 4926** 4927** The safest policy is to invoke these routines 4928** in one of the following ways: 4929** 4930** <ul> 4931** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4932** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4933** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4934** </ul> 4935** 4936** In other words, you should call sqlite3_column_text(), 4937** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4938** into the desired format, then invoke sqlite3_column_bytes() or 4939** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4940** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4941** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4942** with calls to sqlite3_column_bytes(). 4943** 4944** ^The pointers returned are valid until a type conversion occurs as 4945** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4946** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4947** and BLOBs is freed automatically. Do not pass the pointers returned 4948** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4949** [sqlite3_free()]. 4950** 4951** As long as the input parameters are correct, these routines will only 4952** fail if an out-of-memory error occurs during a format conversion. 4953** Only the following subset of interfaces are subject to out-of-memory 4954** errors: 4955** 4956** <ul> 4957** <li> sqlite3_column_blob() 4958** <li> sqlite3_column_text() 4959** <li> sqlite3_column_text16() 4960** <li> sqlite3_column_bytes() 4961** <li> sqlite3_column_bytes16() 4962** </ul> 4963** 4964** If an out-of-memory error occurs, then the return value from these 4965** routines is the same as if the column had contained an SQL NULL value. 4966** Valid SQL NULL returns can be distinguished from out-of-memory errors 4967** by invoking the [sqlite3_errcode()] immediately after the suspect 4968** return value is obtained and before any 4969** other SQLite interface is called on the same [database connection]. 4970*/ 4971const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4972double sqlite3_column_double(sqlite3_stmt*, int iCol); 4973int sqlite3_column_int(sqlite3_stmt*, int iCol); 4974sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4975const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4976const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4977sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4978int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4979int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4980int sqlite3_column_type(sqlite3_stmt*, int iCol); 4981 4982/* 4983** CAPI3REF: Destroy A Prepared Statement Object 4984** DESTRUCTOR: sqlite3_stmt 4985** 4986** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4987** ^If the most recent evaluation of the statement encountered no errors 4988** or if the statement is never been evaluated, then sqlite3_finalize() returns 4989** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4990** sqlite3_finalize(S) returns the appropriate [error code] or 4991** [extended error code]. 4992** 4993** ^The sqlite3_finalize(S) routine can be called at any point during 4994** the life cycle of [prepared statement] S: 4995** before statement S is ever evaluated, after 4996** one or more calls to [sqlite3_reset()], or after any call 4997** to [sqlite3_step()] regardless of whether or not the statement has 4998** completed execution. 4999** 5000** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 5001** 5002** The application must finalize every [prepared statement] in order to avoid 5003** resource leaks. It is a grievous error for the application to try to use 5004** a prepared statement after it has been finalized. Any use of a prepared 5005** statement after it has been finalized can result in undefined and 5006** undesirable behavior such as segfaults and heap corruption. 5007*/ 5008int sqlite3_finalize(sqlite3_stmt *pStmt); 5009 5010/* 5011** CAPI3REF: Reset A Prepared Statement Object 5012** METHOD: sqlite3_stmt 5013** 5014** The sqlite3_reset() function is called to reset a [prepared statement] 5015** object back to its initial state, ready to be re-executed. 5016** ^Any SQL statement variables that had values bound to them using 5017** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 5018** Use [sqlite3_clear_bindings()] to reset the bindings. 5019** 5020** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 5021** back to the beginning of its program. 5022** 5023** ^If the most recent call to [sqlite3_step(S)] for the 5024** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 5025** or if [sqlite3_step(S)] has never before been called on S, 5026** then [sqlite3_reset(S)] returns [SQLITE_OK]. 5027** 5028** ^If the most recent call to [sqlite3_step(S)] for the 5029** [prepared statement] S indicated an error, then 5030** [sqlite3_reset(S)] returns an appropriate [error code]. 5031** 5032** ^The [sqlite3_reset(S)] interface does not change the values 5033** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 5034*/ 5035int sqlite3_reset(sqlite3_stmt *pStmt); 5036 5037/* 5038** CAPI3REF: Create Or Redefine SQL Functions 5039** KEYWORDS: {function creation routines} 5040** METHOD: sqlite3 5041** 5042** ^These functions (collectively known as "function creation routines") 5043** are used to add SQL functions or aggregates or to redefine the behavior 5044** of existing SQL functions or aggregates. The only differences between 5045** the three "sqlite3_create_function*" routines are the text encoding 5046** expected for the second parameter (the name of the function being 5047** created) and the presence or absence of a destructor callback for 5048** the application data pointer. Function sqlite3_create_window_function() 5049** is similar, but allows the user to supply the extra callback functions 5050** needed by [aggregate window functions]. 5051** 5052** ^The first parameter is the [database connection] to which the SQL 5053** function is to be added. ^If an application uses more than one database 5054** connection then application-defined SQL functions must be added 5055** to each database connection separately. 5056** 5057** ^The second parameter is the name of the SQL function to be created or 5058** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 5059** representation, exclusive of the zero-terminator. ^Note that the name 5060** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 5061** ^Any attempt to create a function with a longer name 5062** will result in [SQLITE_MISUSE] being returned. 5063** 5064** ^The third parameter (nArg) 5065** is the number of arguments that the SQL function or 5066** aggregate takes. ^If this parameter is -1, then the SQL function or 5067** aggregate may take any number of arguments between 0 and the limit 5068** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 5069** parameter is less than -1 or greater than 127 then the behavior is 5070** undefined. 5071** 5072** ^The fourth parameter, eTextRep, specifies what 5073** [SQLITE_UTF8 | text encoding] this SQL function prefers for 5074** its parameters. The application should set this parameter to 5075** [SQLITE_UTF16LE] if the function implementation invokes 5076** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 5077** implementation invokes [sqlite3_value_text16be()] on an input, or 5078** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 5079** otherwise. ^The same SQL function may be registered multiple times using 5080** different preferred text encodings, with different implementations for 5081** each encoding. 5082** ^When multiple implementations of the same function are available, SQLite 5083** will pick the one that involves the least amount of data conversion. 5084** 5085** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 5086** to signal that the function will always return the same result given 5087** the same inputs within a single SQL statement. Most SQL functions are 5088** deterministic. The built-in [random()] SQL function is an example of a 5089** function that is not deterministic. The SQLite query planner is able to 5090** perform additional optimizations on deterministic functions, so use 5091** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 5092** 5093** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY] 5094** flag, which if present prevents the function from being invoked from 5095** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions, 5096** index expressions, or the WHERE clause of partial indexes. 5097** 5098** <span style="background-color:#ffff90;"> 5099** For best security, the [SQLITE_DIRECTONLY] flag is recommended for 5100** all application-defined SQL functions that do not need to be 5101** used inside of triggers, view, CHECK constraints, or other elements of 5102** the database schema. This flags is especially recommended for SQL 5103** functions that have side effects or reveal internal application state. 5104** Without this flag, an attacker might be able to modify the schema of 5105** a database file to include invocations of the function with parameters 5106** chosen by the attacker, which the application will then execute when 5107** the database file is opened and read. 5108** </span> 5109** 5110** ^(The fifth parameter is an arbitrary pointer. The implementation of the 5111** function can gain access to this pointer using [sqlite3_user_data()].)^ 5112** 5113** ^The sixth, seventh and eighth parameters passed to the three 5114** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are 5115** pointers to C-language functions that implement the SQL function or 5116** aggregate. ^A scalar SQL function requires an implementation of the xFunc 5117** callback only; NULL pointers must be passed as the xStep and xFinal 5118** parameters. ^An aggregate SQL function requires an implementation of xStep 5119** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 5120** SQL function or aggregate, pass NULL pointers for all three function 5121** callbacks. 5122** 5123** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue 5124** and xInverse) passed to sqlite3_create_window_function are pointers to 5125** C-language callbacks that implement the new function. xStep and xFinal 5126** must both be non-NULL. xValue and xInverse may either both be NULL, in 5127** which case a regular aggregate function is created, or must both be 5128** non-NULL, in which case the new function may be used as either an aggregate 5129** or aggregate window function. More details regarding the implementation 5130** of aggregate window functions are 5131** [user-defined window functions|available here]. 5132** 5133** ^(If the final parameter to sqlite3_create_function_v2() or 5134** sqlite3_create_window_function() is not NULL, then it is destructor for 5135** the application data pointer. The destructor is invoked when the function 5136** is deleted, either by being overloaded or when the database connection 5137** closes.)^ ^The destructor is also invoked if the call to 5138** sqlite3_create_function_v2() fails. ^When the destructor callback is 5139** invoked, it is passed a single argument which is a copy of the application 5140** data pointer which was the fifth parameter to sqlite3_create_function_v2(). 5141** 5142** ^It is permitted to register multiple implementations of the same 5143** functions with the same name but with either differing numbers of 5144** arguments or differing preferred text encodings. ^SQLite will use 5145** the implementation that most closely matches the way in which the 5146** SQL function is used. ^A function implementation with a non-negative 5147** nArg parameter is a better match than a function implementation with 5148** a negative nArg. ^A function where the preferred text encoding 5149** matches the database encoding is a better 5150** match than a function where the encoding is different. 5151** ^A function where the encoding difference is between UTF16le and UTF16be 5152** is a closer match than a function where the encoding difference is 5153** between UTF8 and UTF16. 5154** 5155** ^Built-in functions may be overloaded by new application-defined functions. 5156** 5157** ^An application-defined function is permitted to call other 5158** SQLite interfaces. However, such calls must not 5159** close the database connection nor finalize or reset the prepared 5160** statement in which the function is running. 5161*/ 5162int sqlite3_create_function( 5163 sqlite3 *db, 5164 const char *zFunctionName, 5165 int nArg, 5166 int eTextRep, 5167 void *pApp, 5168 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5169 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5170 void (*xFinal)(sqlite3_context*) 5171); 5172int sqlite3_create_function16( 5173 sqlite3 *db, 5174 const void *zFunctionName, 5175 int nArg, 5176 int eTextRep, 5177 void *pApp, 5178 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5179 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5180 void (*xFinal)(sqlite3_context*) 5181); 5182int sqlite3_create_function_v2( 5183 sqlite3 *db, 5184 const char *zFunctionName, 5185 int nArg, 5186 int eTextRep, 5187 void *pApp, 5188 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5189 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5190 void (*xFinal)(sqlite3_context*), 5191 void(*xDestroy)(void*) 5192); 5193int sqlite3_create_window_function( 5194 sqlite3 *db, 5195 const char *zFunctionName, 5196 int nArg, 5197 int eTextRep, 5198 void *pApp, 5199 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5200 void (*xFinal)(sqlite3_context*), 5201 void (*xValue)(sqlite3_context*), 5202 void (*xInverse)(sqlite3_context*,int,sqlite3_value**), 5203 void(*xDestroy)(void*) 5204); 5205 5206/* 5207** CAPI3REF: Text Encodings 5208** 5209** These constant define integer codes that represent the various 5210** text encodings supported by SQLite. 5211*/ 5212#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 5213#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 5214#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 5215#define SQLITE_UTF16 4 /* Use native byte order */ 5216#define SQLITE_ANY 5 /* Deprecated */ 5217#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 5218 5219/* 5220** CAPI3REF: Function Flags 5221** 5222** These constants may be ORed together with the 5223** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 5224** to [sqlite3_create_function()], [sqlite3_create_function16()], or 5225** [sqlite3_create_function_v2()]. 5226** 5227** <dl> 5228** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd> 5229** The SQLITE_DETERMINISTIC flag means that the new function always gives 5230** the same output when the input parameters are the same. 5231** The [abs|abs() function] is deterministic, for example, but 5232** [randomblob|randomblob()] is not. Functions must 5233** be deterministic in order to be used in certain contexts such as 5234** with the WHERE clause of [partial indexes] or in [generated columns]. 5235** SQLite might also optimize deterministic functions by factoring them 5236** out of inner loops. 5237** </dd> 5238** 5239** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd> 5240** The SQLITE_DIRECTONLY flag means that the function may only be invoked 5241** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in 5242** schema structures such as [CHECK constraints], [DEFAULT clauses], 5243** [expression indexes], [partial indexes], or [generated columns]. 5244** The SQLITE_DIRECTONLY flags is a security feature which is recommended 5245** for all [application-defined SQL functions], and especially for functions 5246** that have side-effects or that could potentially leak sensitive 5247** information. 5248** </dd> 5249** 5250** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd> 5251** The SQLITE_INNOCUOUS flag means that the function is unlikely 5252** to cause problems even if misused. An innocuous function should have 5253** no side effects and should not depend on any values other than its 5254** input parameters. The [abs|abs() function] is an example of an 5255** innocuous function. 5256** The [load_extension() SQL function] is not innocuous because of its 5257** side effects. 5258** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not 5259** exactly the same. The [random|random() function] is an example of a 5260** function that is innocuous but not deterministic. 5261** <p>Some heightened security settings 5262** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF]) 5263** disable the use of SQL functions inside views and triggers and in 5264** schema structures such as [CHECK constraints], [DEFAULT clauses], 5265** [expression indexes], [partial indexes], and [generated columns] unless 5266** the function is tagged with SQLITE_INNOCUOUS. Most built-in functions 5267** are innocuous. Developers are advised to avoid using the 5268** SQLITE_INNOCUOUS flag for application-defined functions unless the 5269** function has been carefully audited and found to be free of potentially 5270** security-adverse side-effects and information-leaks. 5271** </dd> 5272** 5273** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd> 5274** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call 5275** [sqlite3_value_subtype()] to inspect the sub-types of its arguments. 5276** Specifying this flag makes no difference for scalar or aggregate user 5277** functions. However, if it is not specified for a user-defined window 5278** function, then any sub-types belonging to arguments passed to the window 5279** function may be discarded before the window function is called (i.e. 5280** sqlite3_value_subtype() will always return 0). 5281** </dd> 5282** </dl> 5283*/ 5284#define SQLITE_DETERMINISTIC 0x000000800 5285#define SQLITE_DIRECTONLY 0x000080000 5286#define SQLITE_SUBTYPE 0x000100000 5287#define SQLITE_INNOCUOUS 0x000200000 5288 5289/* 5290** CAPI3REF: Deprecated Functions 5291** DEPRECATED 5292** 5293** These functions are [deprecated]. In order to maintain 5294** backwards compatibility with older code, these functions continue 5295** to be supported. However, new applications should avoid 5296** the use of these functions. To encourage programmers to avoid 5297** these functions, we will not explain what they do. 5298*/ 5299#ifndef SQLITE_OMIT_DEPRECATED 5300SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 5301SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 5302SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 5303SQLITE_DEPRECATED int sqlite3_global_recover(void); 5304SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 5305SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 5306 void*,sqlite3_int64); 5307#endif 5308 5309/* 5310** CAPI3REF: Obtaining SQL Values 5311** METHOD: sqlite3_value 5312** 5313** <b>Summary:</b> 5314** <blockquote><table border=0 cellpadding=0 cellspacing=0> 5315** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 5316** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 5317** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 5318** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 5319** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 5320** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 5321** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 5322** the native byteorder 5323** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 5324** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 5325** <tr><td> <td> <td> 5326** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 5327** or a UTF-8 TEXT in bytes 5328** <tr><td><b>sqlite3_value_bytes16 </b> 5329** <td>→ <td>Size of UTF-16 5330** TEXT in bytes 5331** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 5332** datatype of the value 5333** <tr><td><b>sqlite3_value_numeric_type </b> 5334** <td>→ <td>Best numeric datatype of the value 5335** <tr><td><b>sqlite3_value_nochange </b> 5336** <td>→ <td>True if the column is unchanged in an UPDATE 5337** against a virtual table. 5338** <tr><td><b>sqlite3_value_frombind </b> 5339** <td>→ <td>True if value originated from a [bound parameter] 5340** </table></blockquote> 5341** 5342** <b>Details:</b> 5343** 5344** These routines extract type, size, and content information from 5345** [protected sqlite3_value] objects. Protected sqlite3_value objects 5346** are used to pass parameter information into the functions that 5347** implement [application-defined SQL functions] and [virtual tables]. 5348** 5349** These routines work only with [protected sqlite3_value] objects. 5350** Any attempt to use these routines on an [unprotected sqlite3_value] 5351** is not threadsafe. 5352** 5353** ^These routines work just like the corresponding [column access functions] 5354** except that these routines take a single [protected sqlite3_value] object 5355** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 5356** 5357** ^The sqlite3_value_text16() interface extracts a UTF-16 string 5358** in the native byte-order of the host machine. ^The 5359** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 5360** extract UTF-16 strings as big-endian and little-endian respectively. 5361** 5362** ^If [sqlite3_value] object V was initialized 5363** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 5364** and if X and Y are strings that compare equal according to strcmp(X,Y), 5365** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 5366** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 5367** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5368** 5369** ^(The sqlite3_value_type(V) interface returns the 5370** [SQLITE_INTEGER | datatype code] for the initial datatype of the 5371** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 5372** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 5373** Other interfaces might change the datatype for an sqlite3_value object. 5374** For example, if the datatype is initially SQLITE_INTEGER and 5375** sqlite3_value_text(V) is called to extract a text value for that 5376** integer, then subsequent calls to sqlite3_value_type(V) might return 5377** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 5378** occurs is undefined and may change from one release of SQLite to the next. 5379** 5380** ^(The sqlite3_value_numeric_type() interface attempts to apply 5381** numeric affinity to the value. This means that an attempt is 5382** made to convert the value to an integer or floating point. If 5383** such a conversion is possible without loss of information (in other 5384** words, if the value is a string that looks like a number) 5385** then the conversion is performed. Otherwise no conversion occurs. 5386** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 5387** 5388** ^Within the [xUpdate] method of a [virtual table], the 5389** sqlite3_value_nochange(X) interface returns true if and only if 5390** the column corresponding to X is unchanged by the UPDATE operation 5391** that the xUpdate method call was invoked to implement and if 5392** and the prior [xColumn] method call that was invoked to extracted 5393** the value for that column returned without setting a result (probably 5394** because it queried [sqlite3_vtab_nochange()] and found that the column 5395** was unchanging). ^Within an [xUpdate] method, any value for which 5396** sqlite3_value_nochange(X) is true will in all other respects appear 5397** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 5398** than within an [xUpdate] method call for an UPDATE statement, then 5399** the return value is arbitrary and meaningless. 5400** 5401** ^The sqlite3_value_frombind(X) interface returns non-zero if the 5402** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()] 5403** interfaces. ^If X comes from an SQL literal value, or a table column, 5404** or an expression, then sqlite3_value_frombind(X) returns zero. 5405** 5406** Please pay particular attention to the fact that the pointer returned 5407** from [sqlite3_value_blob()], [sqlite3_value_text()], or 5408** [sqlite3_value_text16()] can be invalidated by a subsequent call to 5409** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 5410** or [sqlite3_value_text16()]. 5411** 5412** These routines must be called from the same thread as 5413** the SQL function that supplied the [sqlite3_value*] parameters. 5414** 5415** As long as the input parameter is correct, these routines can only 5416** fail if an out-of-memory error occurs during a format conversion. 5417** Only the following subset of interfaces are subject to out-of-memory 5418** errors: 5419** 5420** <ul> 5421** <li> sqlite3_value_blob() 5422** <li> sqlite3_value_text() 5423** <li> sqlite3_value_text16() 5424** <li> sqlite3_value_text16le() 5425** <li> sqlite3_value_text16be() 5426** <li> sqlite3_value_bytes() 5427** <li> sqlite3_value_bytes16() 5428** </ul> 5429** 5430** If an out-of-memory error occurs, then the return value from these 5431** routines is the same as if the column had contained an SQL NULL value. 5432** Valid SQL NULL returns can be distinguished from out-of-memory errors 5433** by invoking the [sqlite3_errcode()] immediately after the suspect 5434** return value is obtained and before any 5435** other SQLite interface is called on the same [database connection]. 5436*/ 5437const void *sqlite3_value_blob(sqlite3_value*); 5438double sqlite3_value_double(sqlite3_value*); 5439int sqlite3_value_int(sqlite3_value*); 5440sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 5441void *sqlite3_value_pointer(sqlite3_value*, const char*); 5442const unsigned char *sqlite3_value_text(sqlite3_value*); 5443const void *sqlite3_value_text16(sqlite3_value*); 5444const void *sqlite3_value_text16le(sqlite3_value*); 5445const void *sqlite3_value_text16be(sqlite3_value*); 5446int sqlite3_value_bytes(sqlite3_value*); 5447int sqlite3_value_bytes16(sqlite3_value*); 5448int sqlite3_value_type(sqlite3_value*); 5449int sqlite3_value_numeric_type(sqlite3_value*); 5450int sqlite3_value_nochange(sqlite3_value*); 5451int sqlite3_value_frombind(sqlite3_value*); 5452 5453/* 5454** CAPI3REF: Finding The Subtype Of SQL Values 5455** METHOD: sqlite3_value 5456** 5457** The sqlite3_value_subtype(V) function returns the subtype for 5458** an [application-defined SQL function] argument V. The subtype 5459** information can be used to pass a limited amount of context from 5460** one SQL function to another. Use the [sqlite3_result_subtype()] 5461** routine to set the subtype for the return value of an SQL function. 5462*/ 5463unsigned int sqlite3_value_subtype(sqlite3_value*); 5464 5465/* 5466** CAPI3REF: Copy And Free SQL Values 5467** METHOD: sqlite3_value 5468** 5469** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 5470** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 5471** is a [protected sqlite3_value] object even if the input is not. 5472** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 5473** memory allocation fails. 5474** 5475** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 5476** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 5477** then sqlite3_value_free(V) is a harmless no-op. 5478*/ 5479sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 5480void sqlite3_value_free(sqlite3_value*); 5481 5482/* 5483** CAPI3REF: Obtain Aggregate Function Context 5484** METHOD: sqlite3_context 5485** 5486** Implementations of aggregate SQL functions use this 5487** routine to allocate memory for storing their state. 5488** 5489** ^The first time the sqlite3_aggregate_context(C,N) routine is called 5490** for a particular aggregate function, SQLite allocates 5491** N bytes of memory, zeroes out that memory, and returns a pointer 5492** to the new memory. ^On second and subsequent calls to 5493** sqlite3_aggregate_context() for the same aggregate function instance, 5494** the same buffer is returned. Sqlite3_aggregate_context() is normally 5495** called once for each invocation of the xStep callback and then one 5496** last time when the xFinal callback is invoked. ^(When no rows match 5497** an aggregate query, the xStep() callback of the aggregate function 5498** implementation is never called and xFinal() is called exactly once. 5499** In those cases, sqlite3_aggregate_context() might be called for the 5500** first time from within xFinal().)^ 5501** 5502** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 5503** when first called if N is less than or equal to zero or if a memory 5504** allocate error occurs. 5505** 5506** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 5507** determined by the N parameter on first successful call. Changing the 5508** value of N in any subsequent call to sqlite3_aggregate_context() within 5509** the same aggregate function instance will not resize the memory 5510** allocation.)^ Within the xFinal callback, it is customary to set 5511** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 5512** pointless memory allocations occur. 5513** 5514** ^SQLite automatically frees the memory allocated by 5515** sqlite3_aggregate_context() when the aggregate query concludes. 5516** 5517** The first parameter must be a copy of the 5518** [sqlite3_context | SQL function context] that is the first parameter 5519** to the xStep or xFinal callback routine that implements the aggregate 5520** function. 5521** 5522** This routine must be called from the same thread in which 5523** the aggregate SQL function is running. 5524*/ 5525void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 5526 5527/* 5528** CAPI3REF: User Data For Functions 5529** METHOD: sqlite3_context 5530** 5531** ^The sqlite3_user_data() interface returns a copy of 5532** the pointer that was the pUserData parameter (the 5th parameter) 5533** of the [sqlite3_create_function()] 5534** and [sqlite3_create_function16()] routines that originally 5535** registered the application defined function. 5536** 5537** This routine must be called from the same thread in which 5538** the application-defined function is running. 5539*/ 5540void *sqlite3_user_data(sqlite3_context*); 5541 5542/* 5543** CAPI3REF: Database Connection For Functions 5544** METHOD: sqlite3_context 5545** 5546** ^The sqlite3_context_db_handle() interface returns a copy of 5547** the pointer to the [database connection] (the 1st parameter) 5548** of the [sqlite3_create_function()] 5549** and [sqlite3_create_function16()] routines that originally 5550** registered the application defined function. 5551*/ 5552sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 5553 5554/* 5555** CAPI3REF: Function Auxiliary Data 5556** METHOD: sqlite3_context 5557** 5558** These functions may be used by (non-aggregate) SQL functions to 5559** associate metadata with argument values. If the same value is passed to 5560** multiple invocations of the same SQL function during query execution, under 5561** some circumstances the associated metadata may be preserved. An example 5562** of where this might be useful is in a regular-expression matching 5563** function. The compiled version of the regular expression can be stored as 5564** metadata associated with the pattern string. 5565** Then as long as the pattern string remains the same, 5566** the compiled regular expression can be reused on multiple 5567** invocations of the same function. 5568** 5569** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 5570** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 5571** value to the application-defined function. ^N is zero for the left-most 5572** function argument. ^If there is no metadata 5573** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 5574** returns a NULL pointer. 5575** 5576** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 5577** argument of the application-defined function. ^Subsequent 5578** calls to sqlite3_get_auxdata(C,N) return P from the most recent 5579** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5580** NULL if the metadata has been discarded. 5581** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5582** SQLite will invoke the destructor function X with parameter P exactly 5583** once, when the metadata is discarded. 5584** SQLite is free to discard the metadata at any time, including: <ul> 5585** <li> ^(when the corresponding function parameter changes)^, or 5586** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5587** SQL statement)^, or 5588** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5589** parameter)^, or 5590** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5591** allocation error occurs.)^ </ul> 5592** 5593** Note the last bullet in particular. The destructor X in 5594** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5595** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5596** should be called near the end of the function implementation and the 5597** function implementation should not make any use of P after 5598** sqlite3_set_auxdata() has been called. 5599** 5600** ^(In practice, metadata is preserved between function calls for 5601** function parameters that are compile-time constants, including literal 5602** values and [parameters] and expressions composed from the same.)^ 5603** 5604** The value of the N parameter to these interfaces should be non-negative. 5605** Future enhancements may make use of negative N values to define new 5606** kinds of function caching behavior. 5607** 5608** These routines must be called from the same thread in which 5609** the SQL function is running. 5610*/ 5611void *sqlite3_get_auxdata(sqlite3_context*, int N); 5612void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5613 5614 5615/* 5616** CAPI3REF: Constants Defining Special Destructor Behavior 5617** 5618** These are special values for the destructor that is passed in as the 5619** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5620** argument is SQLITE_STATIC, it means that the content pointer is constant 5621** and will never change. It does not need to be destroyed. ^The 5622** SQLITE_TRANSIENT value means that the content will likely change in 5623** the near future and that SQLite should make its own private copy of 5624** the content before returning. 5625** 5626** The typedef is necessary to work around problems in certain 5627** C++ compilers. 5628*/ 5629typedef void (*sqlite3_destructor_type)(void*); 5630#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5631#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5632 5633/* 5634** CAPI3REF: Setting The Result Of An SQL Function 5635** METHOD: sqlite3_context 5636** 5637** These routines are used by the xFunc or xFinal callbacks that 5638** implement SQL functions and aggregates. See 5639** [sqlite3_create_function()] and [sqlite3_create_function16()] 5640** for additional information. 5641** 5642** These functions work very much like the [parameter binding] family of 5643** functions used to bind values to host parameters in prepared statements. 5644** Refer to the [SQL parameter] documentation for additional information. 5645** 5646** ^The sqlite3_result_blob() interface sets the result from 5647** an application-defined function to be the BLOB whose content is pointed 5648** to by the second parameter and which is N bytes long where N is the 5649** third parameter. 5650** 5651** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5652** interfaces set the result of the application-defined function to be 5653** a BLOB containing all zero bytes and N bytes in size. 5654** 5655** ^The sqlite3_result_double() interface sets the result from 5656** an application-defined function to be a floating point value specified 5657** by its 2nd argument. 5658** 5659** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5660** cause the implemented SQL function to throw an exception. 5661** ^SQLite uses the string pointed to by the 5662** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5663** as the text of an error message. ^SQLite interprets the error 5664** message string from sqlite3_result_error() as UTF-8. ^SQLite 5665** interprets the string from sqlite3_result_error16() as UTF-16 using 5666** the same [byte-order determination rules] as [sqlite3_bind_text16()]. 5667** ^If the third parameter to sqlite3_result_error() 5668** or sqlite3_result_error16() is negative then SQLite takes as the error 5669** message all text up through the first zero character. 5670** ^If the third parameter to sqlite3_result_error() or 5671** sqlite3_result_error16() is non-negative then SQLite takes that many 5672** bytes (not characters) from the 2nd parameter as the error message. 5673** ^The sqlite3_result_error() and sqlite3_result_error16() 5674** routines make a private copy of the error message text before 5675** they return. Hence, the calling function can deallocate or 5676** modify the text after they return without harm. 5677** ^The sqlite3_result_error_code() function changes the error code 5678** returned by SQLite as a result of an error in a function. ^By default, 5679** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5680** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5681** 5682** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5683** error indicating that a string or BLOB is too long to represent. 5684** 5685** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5686** error indicating that a memory allocation failed. 5687** 5688** ^The sqlite3_result_int() interface sets the return value 5689** of the application-defined function to be the 32-bit signed integer 5690** value given in the 2nd argument. 5691** ^The sqlite3_result_int64() interface sets the return value 5692** of the application-defined function to be the 64-bit signed integer 5693** value given in the 2nd argument. 5694** 5695** ^The sqlite3_result_null() interface sets the return value 5696** of the application-defined function to be NULL. 5697** 5698** ^The sqlite3_result_text(), sqlite3_result_text16(), 5699** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5700** set the return value of the application-defined function to be 5701** a text string which is represented as UTF-8, UTF-16 native byte order, 5702** UTF-16 little endian, or UTF-16 big endian, respectively. 5703** ^The sqlite3_result_text64() interface sets the return value of an 5704** application-defined function to be a text string in an encoding 5705** specified by the fifth (and last) parameter, which must be one 5706** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5707** ^SQLite takes the text result from the application from 5708** the 2nd parameter of the sqlite3_result_text* interfaces. 5709** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5710** is negative, then SQLite takes result text from the 2nd parameter 5711** through the first zero character. 5712** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5713** is non-negative, then as many bytes (not characters) of the text 5714** pointed to by the 2nd parameter are taken as the application-defined 5715** function result. If the 3rd parameter is non-negative, then it 5716** must be the byte offset into the string where the NUL terminator would 5717** appear if the string where NUL terminated. If any NUL characters occur 5718** in the string at a byte offset that is less than the value of the 3rd 5719** parameter, then the resulting string will contain embedded NULs and the 5720** result of expressions operating on strings with embedded NULs is undefined. 5721** ^If the 4th parameter to the sqlite3_result_text* interfaces 5722** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5723** function as the destructor on the text or BLOB result when it has 5724** finished using that result. 5725** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5726** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5727** assumes that the text or BLOB result is in constant space and does not 5728** copy the content of the parameter nor call a destructor on the content 5729** when it has finished using that result. 5730** ^If the 4th parameter to the sqlite3_result_text* interfaces 5731** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5732** then SQLite makes a copy of the result into space obtained 5733** from [sqlite3_malloc()] before it returns. 5734** 5735** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and 5736** sqlite3_result_text16be() routines, and for sqlite3_result_text64() 5737** when the encoding is not UTF8, if the input UTF16 begins with a 5738** byte-order mark (BOM, U+FEFF) then the BOM is removed from the 5739** string and the rest of the string is interpreted according to the 5740** byte-order specified by the BOM. ^The byte-order specified by 5741** the BOM at the beginning of the text overrides the byte-order 5742** specified by the interface procedure. ^So, for example, if 5743** sqlite3_result_text16le() is invoked with text that begins 5744** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the 5745** first two bytes of input are skipped and the remaining input 5746** is interpreted as UTF16BE text. 5747** 5748** ^For UTF16 input text to the sqlite3_result_text16(), 5749** sqlite3_result_text16be(), sqlite3_result_text16le(), and 5750** sqlite3_result_text64() routines, if the text contains invalid 5751** UTF16 characters, the invalid characters might be converted 5752** into the unicode replacement character, U+FFFD. 5753** 5754** ^The sqlite3_result_value() interface sets the result of 5755** the application-defined function to be a copy of the 5756** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5757** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5758** so that the [sqlite3_value] specified in the parameter may change or 5759** be deallocated after sqlite3_result_value() returns without harm. 5760** ^A [protected sqlite3_value] object may always be used where an 5761** [unprotected sqlite3_value] object is required, so either 5762** kind of [sqlite3_value] object can be used with this interface. 5763** 5764** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5765** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5766** also associates the host-language pointer P or type T with that 5767** NULL value such that the pointer can be retrieved within an 5768** [application-defined SQL function] using [sqlite3_value_pointer()]. 5769** ^If the D parameter is not NULL, then it is a pointer to a destructor 5770** for the P parameter. ^SQLite invokes D with P as its only argument 5771** when SQLite is finished with P. The T parameter should be a static 5772** string and preferably a string literal. The sqlite3_result_pointer() 5773** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5774** 5775** If these routines are called from within the different thread 5776** than the one containing the application-defined function that received 5777** the [sqlite3_context] pointer, the results are undefined. 5778*/ 5779void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5780void sqlite3_result_blob64(sqlite3_context*,const void*, 5781 sqlite3_uint64,void(*)(void*)); 5782void sqlite3_result_double(sqlite3_context*, double); 5783void sqlite3_result_error(sqlite3_context*, const char*, int); 5784void sqlite3_result_error16(sqlite3_context*, const void*, int); 5785void sqlite3_result_error_toobig(sqlite3_context*); 5786void sqlite3_result_error_nomem(sqlite3_context*); 5787void sqlite3_result_error_code(sqlite3_context*, int); 5788void sqlite3_result_int(sqlite3_context*, int); 5789void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5790void sqlite3_result_null(sqlite3_context*); 5791void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5792void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5793 void(*)(void*), unsigned char encoding); 5794void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5795void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5796void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5797void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5798void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5799void sqlite3_result_zeroblob(sqlite3_context*, int n); 5800int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5801 5802 5803/* 5804** CAPI3REF: Setting The Subtype Of An SQL Function 5805** METHOD: sqlite3_context 5806** 5807** The sqlite3_result_subtype(C,T) function causes the subtype of 5808** the result from the [application-defined SQL function] with 5809** [sqlite3_context] C to be the value T. Only the lower 8 bits 5810** of the subtype T are preserved in current versions of SQLite; 5811** higher order bits are discarded. 5812** The number of subtype bytes preserved by SQLite might increase 5813** in future releases of SQLite. 5814*/ 5815void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5816 5817/* 5818** CAPI3REF: Define New Collating Sequences 5819** METHOD: sqlite3 5820** 5821** ^These functions add, remove, or modify a [collation] associated 5822** with the [database connection] specified as the first argument. 5823** 5824** ^The name of the collation is a UTF-8 string 5825** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5826** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5827** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5828** considered to be the same name. 5829** 5830** ^(The third argument (eTextRep) must be one of the constants: 5831** <ul> 5832** <li> [SQLITE_UTF8], 5833** <li> [SQLITE_UTF16LE], 5834** <li> [SQLITE_UTF16BE], 5835** <li> [SQLITE_UTF16], or 5836** <li> [SQLITE_UTF16_ALIGNED]. 5837** </ul>)^ 5838** ^The eTextRep argument determines the encoding of strings passed 5839** to the collating function callback, xCompare. 5840** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5841** force strings to be UTF16 with native byte order. 5842** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5843** on an even byte address. 5844** 5845** ^The fourth argument, pArg, is an application data pointer that is passed 5846** through as the first argument to the collating function callback. 5847** 5848** ^The fifth argument, xCompare, is a pointer to the collating function. 5849** ^Multiple collating functions can be registered using the same name but 5850** with different eTextRep parameters and SQLite will use whichever 5851** function requires the least amount of data transformation. 5852** ^If the xCompare argument is NULL then the collating function is 5853** deleted. ^When all collating functions having the same name are deleted, 5854** that collation is no longer usable. 5855** 5856** ^The collating function callback is invoked with a copy of the pArg 5857** application data pointer and with two strings in the encoding specified 5858** by the eTextRep argument. The two integer parameters to the collating 5859** function callback are the length of the two strings, in bytes. The collating 5860** function must return an integer that is negative, zero, or positive 5861** if the first string is less than, equal to, or greater than the second, 5862** respectively. A collating function must always return the same answer 5863** given the same inputs. If two or more collating functions are registered 5864** to the same collation name (using different eTextRep values) then all 5865** must give an equivalent answer when invoked with equivalent strings. 5866** The collating function must obey the following properties for all 5867** strings A, B, and C: 5868** 5869** <ol> 5870** <li> If A==B then B==A. 5871** <li> If A==B and B==C then A==C. 5872** <li> If A<B THEN B>A. 5873** <li> If A<B and B<C then A<C. 5874** </ol> 5875** 5876** If a collating function fails any of the above constraints and that 5877** collating function is registered and used, then the behavior of SQLite 5878** is undefined. 5879** 5880** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5881** with the addition that the xDestroy callback is invoked on pArg when 5882** the collating function is deleted. 5883** ^Collating functions are deleted when they are overridden by later 5884** calls to the collation creation functions or when the 5885** [database connection] is closed using [sqlite3_close()]. 5886** 5887** ^The xDestroy callback is <u>not</u> called if the 5888** sqlite3_create_collation_v2() function fails. Applications that invoke 5889** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5890** check the return code and dispose of the application data pointer 5891** themselves rather than expecting SQLite to deal with it for them. 5892** This is different from every other SQLite interface. The inconsistency 5893** is unfortunate but cannot be changed without breaking backwards 5894** compatibility. 5895** 5896** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5897*/ 5898int sqlite3_create_collation( 5899 sqlite3*, 5900 const char *zName, 5901 int eTextRep, 5902 void *pArg, 5903 int(*xCompare)(void*,int,const void*,int,const void*) 5904); 5905int sqlite3_create_collation_v2( 5906 sqlite3*, 5907 const char *zName, 5908 int eTextRep, 5909 void *pArg, 5910 int(*xCompare)(void*,int,const void*,int,const void*), 5911 void(*xDestroy)(void*) 5912); 5913int sqlite3_create_collation16( 5914 sqlite3*, 5915 const void *zName, 5916 int eTextRep, 5917 void *pArg, 5918 int(*xCompare)(void*,int,const void*,int,const void*) 5919); 5920 5921/* 5922** CAPI3REF: Collation Needed Callbacks 5923** METHOD: sqlite3 5924** 5925** ^To avoid having to register all collation sequences before a database 5926** can be used, a single callback function may be registered with the 5927** [database connection] to be invoked whenever an undefined collation 5928** sequence is required. 5929** 5930** ^If the function is registered using the sqlite3_collation_needed() API, 5931** then it is passed the names of undefined collation sequences as strings 5932** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5933** the names are passed as UTF-16 in machine native byte order. 5934** ^A call to either function replaces the existing collation-needed callback. 5935** 5936** ^(When the callback is invoked, the first argument passed is a copy 5937** of the second argument to sqlite3_collation_needed() or 5938** sqlite3_collation_needed16(). The second argument is the database 5939** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5940** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5941** sequence function required. The fourth parameter is the name of the 5942** required collation sequence.)^ 5943** 5944** The callback function should register the desired collation using 5945** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5946** [sqlite3_create_collation_v2()]. 5947*/ 5948int sqlite3_collation_needed( 5949 sqlite3*, 5950 void*, 5951 void(*)(void*,sqlite3*,int eTextRep,const char*) 5952); 5953int sqlite3_collation_needed16( 5954 sqlite3*, 5955 void*, 5956 void(*)(void*,sqlite3*,int eTextRep,const void*) 5957); 5958 5959#ifdef SQLITE_ENABLE_CEROD 5960/* 5961** Specify the activation key for a CEROD database. Unless 5962** activated, none of the CEROD routines will work. 5963*/ 5964void sqlite3_activate_cerod( 5965 const char *zPassPhrase /* Activation phrase */ 5966); 5967#endif 5968 5969/* 5970** CAPI3REF: Suspend Execution For A Short Time 5971** 5972** The sqlite3_sleep() function causes the current thread to suspend execution 5973** for at least a number of milliseconds specified in its parameter. 5974** 5975** If the operating system does not support sleep requests with 5976** millisecond time resolution, then the time will be rounded up to 5977** the nearest second. The number of milliseconds of sleep actually 5978** requested from the operating system is returned. 5979** 5980** ^SQLite implements this interface by calling the xSleep() 5981** method of the default [sqlite3_vfs] object. If the xSleep() method 5982** of the default VFS is not implemented correctly, or not implemented at 5983** all, then the behavior of sqlite3_sleep() may deviate from the description 5984** in the previous paragraphs. 5985*/ 5986int sqlite3_sleep(int); 5987 5988/* 5989** CAPI3REF: Name Of The Folder Holding Temporary Files 5990** 5991** ^(If this global variable is made to point to a string which is 5992** the name of a folder (a.k.a. directory), then all temporary files 5993** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5994** will be placed in that directory.)^ ^If this variable 5995** is a NULL pointer, then SQLite performs a search for an appropriate 5996** temporary file directory. 5997** 5998** Applications are strongly discouraged from using this global variable. 5999** It is required to set a temporary folder on Windows Runtime (WinRT). 6000** But for all other platforms, it is highly recommended that applications 6001** neither read nor write this variable. This global variable is a relic 6002** that exists for backwards compatibility of legacy applications and should 6003** be avoided in new projects. 6004** 6005** It is not safe to read or modify this variable in more than one 6006** thread at a time. It is not safe to read or modify this variable 6007** if a [database connection] is being used at the same time in a separate 6008** thread. 6009** It is intended that this variable be set once 6010** as part of process initialization and before any SQLite interface 6011** routines have been called and that this variable remain unchanged 6012** thereafter. 6013** 6014** ^The [temp_store_directory pragma] may modify this variable and cause 6015** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6016** the [temp_store_directory pragma] always assumes that any string 6017** that this variable points to is held in memory obtained from 6018** [sqlite3_malloc] and the pragma may attempt to free that memory 6019** using [sqlite3_free]. 6020** Hence, if this variable is modified directly, either it should be 6021** made NULL or made to point to memory obtained from [sqlite3_malloc] 6022** or else the use of the [temp_store_directory pragma] should be avoided. 6023** Except when requested by the [temp_store_directory pragma], SQLite 6024** does not free the memory that sqlite3_temp_directory points to. If 6025** the application wants that memory to be freed, it must do 6026** so itself, taking care to only do so after all [database connection] 6027** objects have been destroyed. 6028** 6029** <b>Note to Windows Runtime users:</b> The temporary directory must be set 6030** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 6031** features that require the use of temporary files may fail. Here is an 6032** example of how to do this using C++ with the Windows Runtime: 6033** 6034** <blockquote><pre> 6035** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 6036** TemporaryFolder->Path->Data(); 6037** char zPathBuf[MAX_PATH + 1]; 6038** memset(zPathBuf, 0, sizeof(zPathBuf)); 6039** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 6040** NULL, NULL); 6041** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 6042** </pre></blockquote> 6043*/ 6044SQLITE_EXTERN char *sqlite3_temp_directory; 6045 6046/* 6047** CAPI3REF: Name Of The Folder Holding Database Files 6048** 6049** ^(If this global variable is made to point to a string which is 6050** the name of a folder (a.k.a. directory), then all database files 6051** specified with a relative pathname and created or accessed by 6052** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 6053** to be relative to that directory.)^ ^If this variable is a NULL 6054** pointer, then SQLite assumes that all database files specified 6055** with a relative pathname are relative to the current directory 6056** for the process. Only the windows VFS makes use of this global 6057** variable; it is ignored by the unix VFS. 6058** 6059** Changing the value of this variable while a database connection is 6060** open can result in a corrupt database. 6061** 6062** It is not safe to read or modify this variable in more than one 6063** thread at a time. It is not safe to read or modify this variable 6064** if a [database connection] is being used at the same time in a separate 6065** thread. 6066** It is intended that this variable be set once 6067** as part of process initialization and before any SQLite interface 6068** routines have been called and that this variable remain unchanged 6069** thereafter. 6070** 6071** ^The [data_store_directory pragma] may modify this variable and cause 6072** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6073** the [data_store_directory pragma] always assumes that any string 6074** that this variable points to is held in memory obtained from 6075** [sqlite3_malloc] and the pragma may attempt to free that memory 6076** using [sqlite3_free]. 6077** Hence, if this variable is modified directly, either it should be 6078** made NULL or made to point to memory obtained from [sqlite3_malloc] 6079** or else the use of the [data_store_directory pragma] should be avoided. 6080*/ 6081SQLITE_EXTERN char *sqlite3_data_directory; 6082 6083/* 6084** CAPI3REF: Win32 Specific Interface 6085** 6086** These interfaces are available only on Windows. The 6087** [sqlite3_win32_set_directory] interface is used to set the value associated 6088** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to 6089** zValue, depending on the value of the type parameter. The zValue parameter 6090** should be NULL to cause the previous value to be freed via [sqlite3_free]; 6091** a non-NULL value will be copied into memory obtained from [sqlite3_malloc] 6092** prior to being used. The [sqlite3_win32_set_directory] interface returns 6093** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported, 6094** or [SQLITE_NOMEM] if memory could not be allocated. The value of the 6095** [sqlite3_data_directory] variable is intended to act as a replacement for 6096** the current directory on the sub-platforms of Win32 where that concept is 6097** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and 6098** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the 6099** sqlite3_win32_set_directory interface except the string parameter must be 6100** UTF-8 or UTF-16, respectively. 6101*/ 6102int sqlite3_win32_set_directory( 6103 unsigned long type, /* Identifier for directory being set or reset */ 6104 void *zValue /* New value for directory being set or reset */ 6105); 6106int sqlite3_win32_set_directory8(unsigned long type, const char *zValue); 6107int sqlite3_win32_set_directory16(unsigned long type, const void *zValue); 6108 6109/* 6110** CAPI3REF: Win32 Directory Types 6111** 6112** These macros are only available on Windows. They define the allowed values 6113** for the type argument to the [sqlite3_win32_set_directory] interface. 6114*/ 6115#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1 6116#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2 6117 6118/* 6119** CAPI3REF: Test For Auto-Commit Mode 6120** KEYWORDS: {autocommit mode} 6121** METHOD: sqlite3 6122** 6123** ^The sqlite3_get_autocommit() interface returns non-zero or 6124** zero if the given database connection is or is not in autocommit mode, 6125** respectively. ^Autocommit mode is on by default. 6126** ^Autocommit mode is disabled by a [BEGIN] statement. 6127** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 6128** 6129** If certain kinds of errors occur on a statement within a multi-statement 6130** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 6131** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 6132** transaction might be rolled back automatically. The only way to 6133** find out whether SQLite automatically rolled back the transaction after 6134** an error is to use this function. 6135** 6136** If another thread changes the autocommit status of the database 6137** connection while this routine is running, then the return value 6138** is undefined. 6139*/ 6140int sqlite3_get_autocommit(sqlite3*); 6141 6142/* 6143** CAPI3REF: Find The Database Handle Of A Prepared Statement 6144** METHOD: sqlite3_stmt 6145** 6146** ^The sqlite3_db_handle interface returns the [database connection] handle 6147** to which a [prepared statement] belongs. ^The [database connection] 6148** returned by sqlite3_db_handle is the same [database connection] 6149** that was the first argument 6150** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 6151** create the statement in the first place. 6152*/ 6153sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 6154 6155/* 6156** CAPI3REF: Return The Filename For A Database Connection 6157** METHOD: sqlite3 6158** 6159** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename 6160** associated with database N of connection D. 6161** ^If there is no attached database N on the database 6162** connection D, or if database N is a temporary or in-memory database, then 6163** this function will return either a NULL pointer or an empty string. 6164** 6165** ^The string value returned by this routine is owned and managed by 6166** the database connection. ^The value will be valid until the database N 6167** is [DETACH]-ed or until the database connection closes. 6168** 6169** ^The filename returned by this function is the output of the 6170** xFullPathname method of the [VFS]. ^In other words, the filename 6171** will be an absolute pathname, even if the filename used 6172** to open the database originally was a URI or relative pathname. 6173** 6174** If the filename pointer returned by this routine is not NULL, then it 6175** can be used as the filename input parameter to these routines: 6176** <ul> 6177** <li> [sqlite3_uri_parameter()] 6178** <li> [sqlite3_uri_boolean()] 6179** <li> [sqlite3_uri_int64()] 6180** <li> [sqlite3_filename_database()] 6181** <li> [sqlite3_filename_journal()] 6182** <li> [sqlite3_filename_wal()] 6183** </ul> 6184*/ 6185const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 6186 6187/* 6188** CAPI3REF: Determine if a database is read-only 6189** METHOD: sqlite3 6190** 6191** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 6192** of connection D is read-only, 0 if it is read/write, or -1 if N is not 6193** the name of a database on connection D. 6194*/ 6195int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 6196 6197/* 6198** CAPI3REF: Determine the transaction state of a database 6199** METHOD: sqlite3 6200** 6201** ^The sqlite3_txn_state(D,S) interface returns the current 6202** [transaction state] of schema S in database connection D. ^If S is NULL, 6203** then the highest transaction state of any schema on database connection D 6204** is returned. Transaction states are (in order of lowest to highest): 6205** <ol> 6206** <li value="0"> SQLITE_TXN_NONE 6207** <li value="1"> SQLITE_TXN_READ 6208** <li value="2"> SQLITE_TXN_WRITE 6209** </ol> 6210** ^If the S argument to sqlite3_txn_state(D,S) is not the name of 6211** a valid schema, then -1 is returned. 6212*/ 6213int sqlite3_txn_state(sqlite3*,const char *zSchema); 6214 6215/* 6216** CAPI3REF: Allowed return values from [sqlite3_txn_state()] 6217** KEYWORDS: {transaction state} 6218** 6219** These constants define the current transaction state of a database file. 6220** ^The [sqlite3_txn_state(D,S)] interface returns one of these 6221** constants in order to describe the transaction state of schema S 6222** in [database connection] D. 6223** 6224** <dl> 6225** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt> 6226** <dd>The SQLITE_TXN_NONE state means that no transaction is currently 6227** pending.</dd> 6228** 6229** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt> 6230** <dd>The SQLITE_TXN_READ state means that the database is currently 6231** in a read transaction. Content has been read from the database file 6232** but nothing in the database file has changed. The transaction state 6233** will advanced to SQLITE_TXN_WRITE if any changes occur and there are 6234** no other conflicting concurrent write transactions. The transaction 6235** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or 6236** [COMMIT].</dd> 6237** 6238** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt> 6239** <dd>The SQLITE_TXN_WRITE state means that the database is currently 6240** in a write transaction. Content has been written to the database file 6241** but has not yet committed. The transaction state will change to 6242** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd> 6243*/ 6244#define SQLITE_TXN_NONE 0 6245#define SQLITE_TXN_READ 1 6246#define SQLITE_TXN_WRITE 2 6247 6248/* 6249** CAPI3REF: Find the next prepared statement 6250** METHOD: sqlite3 6251** 6252** ^This interface returns a pointer to the next [prepared statement] after 6253** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 6254** then this interface returns a pointer to the first prepared statement 6255** associated with the database connection pDb. ^If no prepared statement 6256** satisfies the conditions of this routine, it returns NULL. 6257** 6258** The [database connection] pointer D in a call to 6259** [sqlite3_next_stmt(D,S)] must refer to an open database 6260** connection and in particular must not be a NULL pointer. 6261*/ 6262sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 6263 6264/* 6265** CAPI3REF: Commit And Rollback Notification Callbacks 6266** METHOD: sqlite3 6267** 6268** ^The sqlite3_commit_hook() interface registers a callback 6269** function to be invoked whenever a transaction is [COMMIT | committed]. 6270** ^Any callback set by a previous call to sqlite3_commit_hook() 6271** for the same database connection is overridden. 6272** ^The sqlite3_rollback_hook() interface registers a callback 6273** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 6274** ^Any callback set by a previous call to sqlite3_rollback_hook() 6275** for the same database connection is overridden. 6276** ^The pArg argument is passed through to the callback. 6277** ^If the callback on a commit hook function returns non-zero, 6278** then the commit is converted into a rollback. 6279** 6280** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 6281** return the P argument from the previous call of the same function 6282** on the same [database connection] D, or NULL for 6283** the first call for each function on D. 6284** 6285** The commit and rollback hook callbacks are not reentrant. 6286** The callback implementation must not do anything that will modify 6287** the database connection that invoked the callback. Any actions 6288** to modify the database connection must be deferred until after the 6289** completion of the [sqlite3_step()] call that triggered the commit 6290** or rollback hook in the first place. 6291** Note that running any other SQL statements, including SELECT statements, 6292** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 6293** the database connections for the meaning of "modify" in this paragraph. 6294** 6295** ^Registering a NULL function disables the callback. 6296** 6297** ^When the commit hook callback routine returns zero, the [COMMIT] 6298** operation is allowed to continue normally. ^If the commit hook 6299** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 6300** ^The rollback hook is invoked on a rollback that results from a commit 6301** hook returning non-zero, just as it would be with any other rollback. 6302** 6303** ^For the purposes of this API, a transaction is said to have been 6304** rolled back if an explicit "ROLLBACK" statement is executed, or 6305** an error or constraint causes an implicit rollback to occur. 6306** ^The rollback callback is not invoked if a transaction is 6307** automatically rolled back because the database connection is closed. 6308** 6309** See also the [sqlite3_update_hook()] interface. 6310*/ 6311void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 6312void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 6313 6314/* 6315** CAPI3REF: Data Change Notification Callbacks 6316** METHOD: sqlite3 6317** 6318** ^The sqlite3_update_hook() interface registers a callback function 6319** with the [database connection] identified by the first argument 6320** to be invoked whenever a row is updated, inserted or deleted in 6321** a [rowid table]. 6322** ^Any callback set by a previous call to this function 6323** for the same database connection is overridden. 6324** 6325** ^The second argument is a pointer to the function to invoke when a 6326** row is updated, inserted or deleted in a rowid table. 6327** ^The first argument to the callback is a copy of the third argument 6328** to sqlite3_update_hook(). 6329** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 6330** or [SQLITE_UPDATE], depending on the operation that caused the callback 6331** to be invoked. 6332** ^The third and fourth arguments to the callback contain pointers to the 6333** database and table name containing the affected row. 6334** ^The final callback parameter is the [rowid] of the row. 6335** ^In the case of an update, this is the [rowid] after the update takes place. 6336** 6337** ^(The update hook is not invoked when internal system tables are 6338** modified (i.e. sqlite_sequence).)^ 6339** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 6340** 6341** ^In the current implementation, the update hook 6342** is not invoked when conflicting rows are deleted because of an 6343** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 6344** invoked when rows are deleted using the [truncate optimization]. 6345** The exceptions defined in this paragraph might change in a future 6346** release of SQLite. 6347** 6348** The update hook implementation must not do anything that will modify 6349** the database connection that invoked the update hook. Any actions 6350** to modify the database connection must be deferred until after the 6351** completion of the [sqlite3_step()] call that triggered the update hook. 6352** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 6353** database connections for the meaning of "modify" in this paragraph. 6354** 6355** ^The sqlite3_update_hook(D,C,P) function 6356** returns the P argument from the previous call 6357** on the same [database connection] D, or NULL for 6358** the first call on D. 6359** 6360** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 6361** and [sqlite3_preupdate_hook()] interfaces. 6362*/ 6363void *sqlite3_update_hook( 6364 sqlite3*, 6365 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 6366 void* 6367); 6368 6369/* 6370** CAPI3REF: Enable Or Disable Shared Pager Cache 6371** 6372** ^(This routine enables or disables the sharing of the database cache 6373** and schema data structures between [database connection | connections] 6374** to the same database. Sharing is enabled if the argument is true 6375** and disabled if the argument is false.)^ 6376** 6377** ^Cache sharing is enabled and disabled for an entire process. 6378** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 6379** In prior versions of SQLite, 6380** sharing was enabled or disabled for each thread separately. 6381** 6382** ^(The cache sharing mode set by this interface effects all subsequent 6383** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 6384** Existing database connections continue to use the sharing mode 6385** that was in effect at the time they were opened.)^ 6386** 6387** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 6388** successfully. An [error code] is returned otherwise.)^ 6389** 6390** ^Shared cache is disabled by default. It is recommended that it stay 6391** that way. In other words, do not use this routine. This interface 6392** continues to be provided for historical compatibility, but its use is 6393** discouraged. Any use of shared cache is discouraged. If shared cache 6394** must be used, it is recommended that shared cache only be enabled for 6395** individual database connections using the [sqlite3_open_v2()] interface 6396** with the [SQLITE_OPEN_SHAREDCACHE] flag. 6397** 6398** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 6399** and will always return SQLITE_MISUSE. On those systems, 6400** shared cache mode should be enabled per-database connection via 6401** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 6402** 6403** This interface is threadsafe on processors where writing a 6404** 32-bit integer is atomic. 6405** 6406** See Also: [SQLite Shared-Cache Mode] 6407*/ 6408int sqlite3_enable_shared_cache(int); 6409 6410/* 6411** CAPI3REF: Attempt To Free Heap Memory 6412** 6413** ^The sqlite3_release_memory() interface attempts to free N bytes 6414** of heap memory by deallocating non-essential memory allocations 6415** held by the database library. Memory used to cache database 6416** pages to improve performance is an example of non-essential memory. 6417** ^sqlite3_release_memory() returns the number of bytes actually freed, 6418** which might be more or less than the amount requested. 6419** ^The sqlite3_release_memory() routine is a no-op returning zero 6420** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 6421** 6422** See also: [sqlite3_db_release_memory()] 6423*/ 6424int sqlite3_release_memory(int); 6425 6426/* 6427** CAPI3REF: Free Memory Used By A Database Connection 6428** METHOD: sqlite3 6429** 6430** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 6431** memory as possible from database connection D. Unlike the 6432** [sqlite3_release_memory()] interface, this interface is in effect even 6433** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 6434** omitted. 6435** 6436** See also: [sqlite3_release_memory()] 6437*/ 6438int sqlite3_db_release_memory(sqlite3*); 6439 6440/* 6441** CAPI3REF: Impose A Limit On Heap Size 6442** 6443** These interfaces impose limits on the amount of heap memory that will be 6444** by all database connections within a single process. 6445** 6446** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 6447** soft limit on the amount of heap memory that may be allocated by SQLite. 6448** ^SQLite strives to keep heap memory utilization below the soft heap 6449** limit by reducing the number of pages held in the page cache 6450** as heap memory usages approaches the limit. 6451** ^The soft heap limit is "soft" because even though SQLite strives to stay 6452** below the limit, it will exceed the limit rather than generate 6453** an [SQLITE_NOMEM] error. In other words, the soft heap limit 6454** is advisory only. 6455** 6456** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of 6457** N bytes on the amount of memory that will be allocated. ^The 6458** sqlite3_hard_heap_limit64(N) interface is similar to 6459** sqlite3_soft_heap_limit64(N) except that memory allocations will fail 6460** when the hard heap limit is reached. 6461** 6462** ^The return value from both sqlite3_soft_heap_limit64() and 6463** sqlite3_hard_heap_limit64() is the size of 6464** the heap limit prior to the call, or negative in the case of an 6465** error. ^If the argument N is negative 6466** then no change is made to the heap limit. Hence, the current 6467** size of heap limits can be determined by invoking 6468** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1). 6469** 6470** ^Setting the heap limits to zero disables the heap limiter mechanism. 6471** 6472** ^The soft heap limit may not be greater than the hard heap limit. 6473** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N) 6474** is invoked with a value of N that is greater than the hard heap limit, 6475** the the soft heap limit is set to the value of the hard heap limit. 6476** ^The soft heap limit is automatically enabled whenever the hard heap 6477** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and 6478** the soft heap limit is outside the range of 1..N, then the soft heap 6479** limit is set to N. ^Invoking sqlite3_soft_heap_limit64(0) when the 6480** hard heap limit is enabled makes the soft heap limit equal to the 6481** hard heap limit. 6482** 6483** The memory allocation limits can also be adjusted using 6484** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit]. 6485** 6486** ^(The heap limits are not enforced in the current implementation 6487** if one or more of following conditions are true: 6488** 6489** <ul> 6490** <li> The limit value is set to zero. 6491** <li> Memory accounting is disabled using a combination of the 6492** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 6493** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 6494** <li> An alternative page cache implementation is specified using 6495** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 6496** <li> The page cache allocates from its own memory pool supplied 6497** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 6498** from the heap. 6499** </ul>)^ 6500** 6501** The circumstances under which SQLite will enforce the heap limits may 6502** changes in future releases of SQLite. 6503*/ 6504sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 6505sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N); 6506 6507/* 6508** CAPI3REF: Deprecated Soft Heap Limit Interface 6509** DEPRECATED 6510** 6511** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 6512** interface. This routine is provided for historical compatibility 6513** only. All new applications should use the 6514** [sqlite3_soft_heap_limit64()] interface rather than this one. 6515*/ 6516SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 6517 6518 6519/* 6520** CAPI3REF: Extract Metadata About A Column Of A Table 6521** METHOD: sqlite3 6522** 6523** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 6524** information about column C of table T in database D 6525** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 6526** interface returns SQLITE_OK and fills in the non-NULL pointers in 6527** the final five arguments with appropriate values if the specified 6528** column exists. ^The sqlite3_table_column_metadata() interface returns 6529** SQLITE_ERROR if the specified column does not exist. 6530** ^If the column-name parameter to sqlite3_table_column_metadata() is a 6531** NULL pointer, then this routine simply checks for the existence of the 6532** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 6533** does not. If the table name parameter T in a call to 6534** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 6535** undefined behavior. 6536** 6537** ^The column is identified by the second, third and fourth parameters to 6538** this function. ^(The second parameter is either the name of the database 6539** (i.e. "main", "temp", or an attached database) containing the specified 6540** table or NULL.)^ ^If it is NULL, then all attached databases are searched 6541** for the table using the same algorithm used by the database engine to 6542** resolve unqualified table references. 6543** 6544** ^The third and fourth parameters to this function are the table and column 6545** name of the desired column, respectively. 6546** 6547** ^Metadata is returned by writing to the memory locations passed as the 5th 6548** and subsequent parameters to this function. ^Any of these arguments may be 6549** NULL, in which case the corresponding element of metadata is omitted. 6550** 6551** ^(<blockquote> 6552** <table border="1"> 6553** <tr><th> Parameter <th> Output<br>Type <th> Description 6554** 6555** <tr><td> 5th <td> const char* <td> Data type 6556** <tr><td> 6th <td> const char* <td> Name of default collation sequence 6557** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 6558** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 6559** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 6560** </table> 6561** </blockquote>)^ 6562** 6563** ^The memory pointed to by the character pointers returned for the 6564** declaration type and collation sequence is valid until the next 6565** call to any SQLite API function. 6566** 6567** ^If the specified table is actually a view, an [error code] is returned. 6568** 6569** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 6570** is not a [WITHOUT ROWID] table and an 6571** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 6572** parameters are set for the explicitly declared column. ^(If there is no 6573** [INTEGER PRIMARY KEY] column, then the outputs 6574** for the [rowid] are set as follows: 6575** 6576** <pre> 6577** data type: "INTEGER" 6578** collation sequence: "BINARY" 6579** not null: 0 6580** primary key: 1 6581** auto increment: 0 6582** </pre>)^ 6583** 6584** ^This function causes all database schemas to be read from disk and 6585** parsed, if that has not already been done, and returns an error if 6586** any errors are encountered while loading the schema. 6587*/ 6588int sqlite3_table_column_metadata( 6589 sqlite3 *db, /* Connection handle */ 6590 const char *zDbName, /* Database name or NULL */ 6591 const char *zTableName, /* Table name */ 6592 const char *zColumnName, /* Column name */ 6593 char const **pzDataType, /* OUTPUT: Declared data type */ 6594 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 6595 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 6596 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 6597 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 6598); 6599 6600/* 6601** CAPI3REF: Load An Extension 6602** METHOD: sqlite3 6603** 6604** ^This interface loads an SQLite extension library from the named file. 6605** 6606** ^The sqlite3_load_extension() interface attempts to load an 6607** [SQLite extension] library contained in the file zFile. If 6608** the file cannot be loaded directly, attempts are made to load 6609** with various operating-system specific extensions added. 6610** So for example, if "samplelib" cannot be loaded, then names like 6611** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 6612** be tried also. 6613** 6614** ^The entry point is zProc. 6615** ^(zProc may be 0, in which case SQLite will try to come up with an 6616** entry point name on its own. It first tries "sqlite3_extension_init". 6617** If that does not work, it constructs a name "sqlite3_X_init" where the 6618** X is consists of the lower-case equivalent of all ASCII alphabetic 6619** characters in the filename from the last "/" to the first following 6620** "." and omitting any initial "lib".)^ 6621** ^The sqlite3_load_extension() interface returns 6622** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 6623** ^If an error occurs and pzErrMsg is not 0, then the 6624** [sqlite3_load_extension()] interface shall attempt to 6625** fill *pzErrMsg with error message text stored in memory 6626** obtained from [sqlite3_malloc()]. The calling function 6627** should free this memory by calling [sqlite3_free()]. 6628** 6629** ^Extension loading must be enabled using 6630** [sqlite3_enable_load_extension()] or 6631** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 6632** prior to calling this API, 6633** otherwise an error will be returned. 6634** 6635** <b>Security warning:</b> It is recommended that the 6636** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 6637** interface. The use of the [sqlite3_enable_load_extension()] interface 6638** should be avoided. This will keep the SQL function [load_extension()] 6639** disabled and prevent SQL injections from giving attackers 6640** access to extension loading capabilities. 6641** 6642** See also the [load_extension() SQL function]. 6643*/ 6644int sqlite3_load_extension( 6645 sqlite3 *db, /* Load the extension into this database connection */ 6646 const char *zFile, /* Name of the shared library containing extension */ 6647 const char *zProc, /* Entry point. Derived from zFile if 0 */ 6648 char **pzErrMsg /* Put error message here if not 0 */ 6649); 6650 6651/* 6652** CAPI3REF: Enable Or Disable Extension Loading 6653** METHOD: sqlite3 6654** 6655** ^So as not to open security holes in older applications that are 6656** unprepared to deal with [extension loading], and as a means of disabling 6657** [extension loading] while evaluating user-entered SQL, the following API 6658** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 6659** 6660** ^Extension loading is off by default. 6661** ^Call the sqlite3_enable_load_extension() routine with onoff==1 6662** to turn extension loading on and call it with onoff==0 to turn 6663** it back off again. 6664** 6665** ^This interface enables or disables both the C-API 6666** [sqlite3_load_extension()] and the SQL function [load_extension()]. 6667** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 6668** to enable or disable only the C-API.)^ 6669** 6670** <b>Security warning:</b> It is recommended that extension loading 6671** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 6672** rather than this interface, so the [load_extension()] SQL function 6673** remains disabled. This will prevent SQL injections from giving attackers 6674** access to extension loading capabilities. 6675*/ 6676int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6677 6678/* 6679** CAPI3REF: Automatically Load Statically Linked Extensions 6680** 6681** ^This interface causes the xEntryPoint() function to be invoked for 6682** each new [database connection] that is created. The idea here is that 6683** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6684** that is to be automatically loaded into all new database connections. 6685** 6686** ^(Even though the function prototype shows that xEntryPoint() takes 6687** no arguments and returns void, SQLite invokes xEntryPoint() with three 6688** arguments and expects an integer result as if the signature of the 6689** entry point where as follows: 6690** 6691** <blockquote><pre> 6692** int xEntryPoint( 6693** sqlite3 *db, 6694** const char **pzErrMsg, 6695** const struct sqlite3_api_routines *pThunk 6696** ); 6697** </pre></blockquote>)^ 6698** 6699** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6700** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6701** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6702** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6703** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6704** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6705** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6706** 6707** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6708** on the list of automatic extensions is a harmless no-op. ^No entry point 6709** will be called more than once for each database connection that is opened. 6710** 6711** See also: [sqlite3_reset_auto_extension()] 6712** and [sqlite3_cancel_auto_extension()] 6713*/ 6714int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6715 6716/* 6717** CAPI3REF: Cancel Automatic Extension Loading 6718** 6719** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6720** initialization routine X that was registered using a prior call to 6721** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6722** routine returns 1 if initialization routine X was successfully 6723** unregistered and it returns 0 if X was not on the list of initialization 6724** routines. 6725*/ 6726int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6727 6728/* 6729** CAPI3REF: Reset Automatic Extension Loading 6730** 6731** ^This interface disables all automatic extensions previously 6732** registered using [sqlite3_auto_extension()]. 6733*/ 6734void sqlite3_reset_auto_extension(void); 6735 6736/* 6737** The interface to the virtual-table mechanism is currently considered 6738** to be experimental. The interface might change in incompatible ways. 6739** If this is a problem for you, do not use the interface at this time. 6740** 6741** When the virtual-table mechanism stabilizes, we will declare the 6742** interface fixed, support it indefinitely, and remove this comment. 6743*/ 6744 6745/* 6746** Structures used by the virtual table interface 6747*/ 6748typedef struct sqlite3_vtab sqlite3_vtab; 6749typedef struct sqlite3_index_info sqlite3_index_info; 6750typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6751typedef struct sqlite3_module sqlite3_module; 6752 6753/* 6754** CAPI3REF: Virtual Table Object 6755** KEYWORDS: sqlite3_module {virtual table module} 6756** 6757** This structure, sometimes called a "virtual table module", 6758** defines the implementation of a [virtual table]. 6759** This structure consists mostly of methods for the module. 6760** 6761** ^A virtual table module is created by filling in a persistent 6762** instance of this structure and passing a pointer to that instance 6763** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6764** ^The registration remains valid until it is replaced by a different 6765** module or until the [database connection] closes. The content 6766** of this structure must not change while it is registered with 6767** any database connection. 6768*/ 6769struct sqlite3_module { 6770 int iVersion; 6771 int (*xCreate)(sqlite3*, void *pAux, 6772 int argc, const char *const*argv, 6773 sqlite3_vtab **ppVTab, char**); 6774 int (*xConnect)(sqlite3*, void *pAux, 6775 int argc, const char *const*argv, 6776 sqlite3_vtab **ppVTab, char**); 6777 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6778 int (*xDisconnect)(sqlite3_vtab *pVTab); 6779 int (*xDestroy)(sqlite3_vtab *pVTab); 6780 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6781 int (*xClose)(sqlite3_vtab_cursor*); 6782 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6783 int argc, sqlite3_value **argv); 6784 int (*xNext)(sqlite3_vtab_cursor*); 6785 int (*xEof)(sqlite3_vtab_cursor*); 6786 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6787 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6788 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6789 int (*xBegin)(sqlite3_vtab *pVTab); 6790 int (*xSync)(sqlite3_vtab *pVTab); 6791 int (*xCommit)(sqlite3_vtab *pVTab); 6792 int (*xRollback)(sqlite3_vtab *pVTab); 6793 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6794 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6795 void **ppArg); 6796 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6797 /* The methods above are in version 1 of the sqlite_module object. Those 6798 ** below are for version 2 and greater. */ 6799 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6800 int (*xRelease)(sqlite3_vtab *pVTab, int); 6801 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6802 /* The methods above are in versions 1 and 2 of the sqlite_module object. 6803 ** Those below are for version 3 and greater. */ 6804 int (*xShadowName)(const char*); 6805}; 6806 6807/* 6808** CAPI3REF: Virtual Table Indexing Information 6809** KEYWORDS: sqlite3_index_info 6810** 6811** The sqlite3_index_info structure and its substructures is used as part 6812** of the [virtual table] interface to 6813** pass information into and receive the reply from the [xBestIndex] 6814** method of a [virtual table module]. The fields under **Inputs** are the 6815** inputs to xBestIndex and are read-only. xBestIndex inserts its 6816** results into the **Outputs** fields. 6817** 6818** ^(The aConstraint[] array records WHERE clause constraints of the form: 6819** 6820** <blockquote>column OP expr</blockquote> 6821** 6822** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6823** stored in aConstraint[].op using one of the 6824** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6825** ^(The index of the column is stored in 6826** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6827** expr on the right-hand side can be evaluated (and thus the constraint 6828** is usable) and false if it cannot.)^ 6829** 6830** ^The optimizer automatically inverts terms of the form "expr OP column" 6831** and makes other simplifications to the WHERE clause in an attempt to 6832** get as many WHERE clause terms into the form shown above as possible. 6833** ^The aConstraint[] array only reports WHERE clause terms that are 6834** relevant to the particular virtual table being queried. 6835** 6836** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6837** ^Each term of aOrderBy records a column of the ORDER BY clause. 6838** 6839** The colUsed field indicates which columns of the virtual table may be 6840** required by the current scan. Virtual table columns are numbered from 6841** zero in the order in which they appear within the CREATE TABLE statement 6842** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6843** the corresponding bit is set within the colUsed mask if the column may be 6844** required by SQLite. If the table has at least 64 columns and any column 6845** to the right of the first 63 is required, then bit 63 of colUsed is also 6846** set. In other words, column iCol may be required if the expression 6847** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6848** non-zero. 6849** 6850** The [xBestIndex] method must fill aConstraintUsage[] with information 6851** about what parameters to pass to xFilter. ^If argvIndex>0 then 6852** the right-hand side of the corresponding aConstraint[] is evaluated 6853** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6854** is true, then the constraint is assumed to be fully handled by the 6855** virtual table and might not be checked again by the byte code.)^ ^(The 6856** aConstraintUsage[].omit flag is an optimization hint. When the omit flag 6857** is left in its default setting of false, the constraint will always be 6858** checked separately in byte code. If the omit flag is change to true, then 6859** the constraint may or may not be checked in byte code. In other words, 6860** when the omit flag is true there is no guarantee that the constraint will 6861** not be checked again using byte code.)^ 6862** 6863** ^The idxNum and idxPtr values are recorded and passed into the 6864** [xFilter] method. 6865** ^[sqlite3_free()] is used to free idxPtr if and only if 6866** needToFreeIdxPtr is true. 6867** 6868** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6869** the correct order to satisfy the ORDER BY clause so that no separate 6870** sorting step is required. 6871** 6872** ^The estimatedCost value is an estimate of the cost of a particular 6873** strategy. A cost of N indicates that the cost of the strategy is similar 6874** to a linear scan of an SQLite table with N rows. A cost of log(N) 6875** indicates that the expense of the operation is similar to that of a 6876** binary search on a unique indexed field of an SQLite table with N rows. 6877** 6878** ^The estimatedRows value is an estimate of the number of rows that 6879** will be returned by the strategy. 6880** 6881** The xBestIndex method may optionally populate the idxFlags field with a 6882** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6883** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6884** assumes that the strategy may visit at most one row. 6885** 6886** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6887** SQLite also assumes that if a call to the xUpdate() method is made as 6888** part of the same statement to delete or update a virtual table row and the 6889** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6890** any database changes. In other words, if the xUpdate() returns 6891** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6892** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6893** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6894** the xUpdate method are automatically rolled back by SQLite. 6895** 6896** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6897** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6898** If a virtual table extension is 6899** used with an SQLite version earlier than 3.8.2, the results of attempting 6900** to read or write the estimatedRows field are undefined (but are likely 6901** to include crashing the application). The estimatedRows field should 6902** therefore only be used if [sqlite3_libversion_number()] returns a 6903** value greater than or equal to 3008002. Similarly, the idxFlags field 6904** was added for [version 3.9.0] ([dateof:3.9.0]). 6905** It may therefore only be used if 6906** sqlite3_libversion_number() returns a value greater than or equal to 6907** 3009000. 6908*/ 6909struct sqlite3_index_info { 6910 /* Inputs */ 6911 int nConstraint; /* Number of entries in aConstraint */ 6912 struct sqlite3_index_constraint { 6913 int iColumn; /* Column constrained. -1 for ROWID */ 6914 unsigned char op; /* Constraint operator */ 6915 unsigned char usable; /* True if this constraint is usable */ 6916 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6917 } *aConstraint; /* Table of WHERE clause constraints */ 6918 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6919 struct sqlite3_index_orderby { 6920 int iColumn; /* Column number */ 6921 unsigned char desc; /* True for DESC. False for ASC. */ 6922 } *aOrderBy; /* The ORDER BY clause */ 6923 /* Outputs */ 6924 struct sqlite3_index_constraint_usage { 6925 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6926 unsigned char omit; /* Do not code a test for this constraint */ 6927 } *aConstraintUsage; 6928 int idxNum; /* Number used to identify the index */ 6929 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6930 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6931 int orderByConsumed; /* True if output is already ordered */ 6932 double estimatedCost; /* Estimated cost of using this index */ 6933 /* Fields below are only available in SQLite 3.8.2 and later */ 6934 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6935 /* Fields below are only available in SQLite 3.9.0 and later */ 6936 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6937 /* Fields below are only available in SQLite 3.10.0 and later */ 6938 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6939}; 6940 6941/* 6942** CAPI3REF: Virtual Table Scan Flags 6943** 6944** Virtual table implementations are allowed to set the 6945** [sqlite3_index_info].idxFlags field to some combination of 6946** these bits. 6947*/ 6948#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6949 6950/* 6951** CAPI3REF: Virtual Table Constraint Operator Codes 6952** 6953** These macros define the allowed values for the 6954** [sqlite3_index_info].aConstraint[].op field. Each value represents 6955** an operator that is part of a constraint term in the wHERE clause of 6956** a query that uses a [virtual table]. 6957*/ 6958#define SQLITE_INDEX_CONSTRAINT_EQ 2 6959#define SQLITE_INDEX_CONSTRAINT_GT 4 6960#define SQLITE_INDEX_CONSTRAINT_LE 8 6961#define SQLITE_INDEX_CONSTRAINT_LT 16 6962#define SQLITE_INDEX_CONSTRAINT_GE 32 6963#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6964#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6965#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6966#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6967#define SQLITE_INDEX_CONSTRAINT_NE 68 6968#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6969#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6970#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6971#define SQLITE_INDEX_CONSTRAINT_IS 72 6972#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150 6973 6974/* 6975** CAPI3REF: Register A Virtual Table Implementation 6976** METHOD: sqlite3 6977** 6978** ^These routines are used to register a new [virtual table module] name. 6979** ^Module names must be registered before 6980** creating a new [virtual table] using the module and before using a 6981** preexisting [virtual table] for the module. 6982** 6983** ^The module name is registered on the [database connection] specified 6984** by the first parameter. ^The name of the module is given by the 6985** second parameter. ^The third parameter is a pointer to 6986** the implementation of the [virtual table module]. ^The fourth 6987** parameter is an arbitrary client data pointer that is passed through 6988** into the [xCreate] and [xConnect] methods of the virtual table module 6989** when a new virtual table is be being created or reinitialized. 6990** 6991** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6992** is a pointer to a destructor for the pClientData. ^SQLite will 6993** invoke the destructor function (if it is not NULL) when SQLite 6994** no longer needs the pClientData pointer. ^The destructor will also 6995** be invoked if the call to sqlite3_create_module_v2() fails. 6996** ^The sqlite3_create_module() 6997** interface is equivalent to sqlite3_create_module_v2() with a NULL 6998** destructor. 6999** 7000** ^If the third parameter (the pointer to the sqlite3_module object) is 7001** NULL then no new module is create and any existing modules with the 7002** same name are dropped. 7003** 7004** See also: [sqlite3_drop_modules()] 7005*/ 7006int sqlite3_create_module( 7007 sqlite3 *db, /* SQLite connection to register module with */ 7008 const char *zName, /* Name of the module */ 7009 const sqlite3_module *p, /* Methods for the module */ 7010 void *pClientData /* Client data for xCreate/xConnect */ 7011); 7012int sqlite3_create_module_v2( 7013 sqlite3 *db, /* SQLite connection to register module with */ 7014 const char *zName, /* Name of the module */ 7015 const sqlite3_module *p, /* Methods for the module */ 7016 void *pClientData, /* Client data for xCreate/xConnect */ 7017 void(*xDestroy)(void*) /* Module destructor function */ 7018); 7019 7020/* 7021** CAPI3REF: Remove Unnecessary Virtual Table Implementations 7022** METHOD: sqlite3 7023** 7024** ^The sqlite3_drop_modules(D,L) interface removes all virtual 7025** table modules from database connection D except those named on list L. 7026** The L parameter must be either NULL or a pointer to an array of pointers 7027** to strings where the array is terminated by a single NULL pointer. 7028** ^If the L parameter is NULL, then all virtual table modules are removed. 7029** 7030** See also: [sqlite3_create_module()] 7031*/ 7032int sqlite3_drop_modules( 7033 sqlite3 *db, /* Remove modules from this connection */ 7034 const char **azKeep /* Except, do not remove the ones named here */ 7035); 7036 7037/* 7038** CAPI3REF: Virtual Table Instance Object 7039** KEYWORDS: sqlite3_vtab 7040** 7041** Every [virtual table module] implementation uses a subclass 7042** of this object to describe a particular instance 7043** of the [virtual table]. Each subclass will 7044** be tailored to the specific needs of the module implementation. 7045** The purpose of this superclass is to define certain fields that are 7046** common to all module implementations. 7047** 7048** ^Virtual tables methods can set an error message by assigning a 7049** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 7050** take care that any prior string is freed by a call to [sqlite3_free()] 7051** prior to assigning a new string to zErrMsg. ^After the error message 7052** is delivered up to the client application, the string will be automatically 7053** freed by sqlite3_free() and the zErrMsg field will be zeroed. 7054*/ 7055struct sqlite3_vtab { 7056 const sqlite3_module *pModule; /* The module for this virtual table */ 7057 int nRef; /* Number of open cursors */ 7058 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 7059 /* Virtual table implementations will typically add additional fields */ 7060}; 7061 7062/* 7063** CAPI3REF: Virtual Table Cursor Object 7064** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 7065** 7066** Every [virtual table module] implementation uses a subclass of the 7067** following structure to describe cursors that point into the 7068** [virtual table] and are used 7069** to loop through the virtual table. Cursors are created using the 7070** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 7071** by the [sqlite3_module.xClose | xClose] method. Cursors are used 7072** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 7073** of the module. Each module implementation will define 7074** the content of a cursor structure to suit its own needs. 7075** 7076** This superclass exists in order to define fields of the cursor that 7077** are common to all implementations. 7078*/ 7079struct sqlite3_vtab_cursor { 7080 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 7081 /* Virtual table implementations will typically add additional fields */ 7082}; 7083 7084/* 7085** CAPI3REF: Declare The Schema Of A Virtual Table 7086** 7087** ^The [xCreate] and [xConnect] methods of a 7088** [virtual table module] call this interface 7089** to declare the format (the names and datatypes of the columns) of 7090** the virtual tables they implement. 7091*/ 7092int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 7093 7094/* 7095** CAPI3REF: Overload A Function For A Virtual Table 7096** METHOD: sqlite3 7097** 7098** ^(Virtual tables can provide alternative implementations of functions 7099** using the [xFindFunction] method of the [virtual table module]. 7100** But global versions of those functions 7101** must exist in order to be overloaded.)^ 7102** 7103** ^(This API makes sure a global version of a function with a particular 7104** name and number of parameters exists. If no such function exists 7105** before this API is called, a new function is created.)^ ^The implementation 7106** of the new function always causes an exception to be thrown. So 7107** the new function is not good for anything by itself. Its only 7108** purpose is to be a placeholder function that can be overloaded 7109** by a [virtual table]. 7110*/ 7111int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 7112 7113/* 7114** The interface to the virtual-table mechanism defined above (back up 7115** to a comment remarkably similar to this one) is currently considered 7116** to be experimental. The interface might change in incompatible ways. 7117** If this is a problem for you, do not use the interface at this time. 7118** 7119** When the virtual-table mechanism stabilizes, we will declare the 7120** interface fixed, support it indefinitely, and remove this comment. 7121*/ 7122 7123/* 7124** CAPI3REF: A Handle To An Open BLOB 7125** KEYWORDS: {BLOB handle} {BLOB handles} 7126** 7127** An instance of this object represents an open BLOB on which 7128** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 7129** ^Objects of this type are created by [sqlite3_blob_open()] 7130** and destroyed by [sqlite3_blob_close()]. 7131** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 7132** can be used to read or write small subsections of the BLOB. 7133** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 7134*/ 7135typedef struct sqlite3_blob sqlite3_blob; 7136 7137/* 7138** CAPI3REF: Open A BLOB For Incremental I/O 7139** METHOD: sqlite3 7140** CONSTRUCTOR: sqlite3_blob 7141** 7142** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 7143** in row iRow, column zColumn, table zTable in database zDb; 7144** in other words, the same BLOB that would be selected by: 7145** 7146** <pre> 7147** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 7148** </pre>)^ 7149** 7150** ^(Parameter zDb is not the filename that contains the database, but 7151** rather the symbolic name of the database. For attached databases, this is 7152** the name that appears after the AS keyword in the [ATTACH] statement. 7153** For the main database file, the database name is "main". For TEMP 7154** tables, the database name is "temp".)^ 7155** 7156** ^If the flags parameter is non-zero, then the BLOB is opened for read 7157** and write access. ^If the flags parameter is zero, the BLOB is opened for 7158** read-only access. 7159** 7160** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 7161** in *ppBlob. Otherwise an [error code] is returned and, unless the error 7162** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 7163** the API is not misused, it is always safe to call [sqlite3_blob_close()] 7164** on *ppBlob after this function it returns. 7165** 7166** This function fails with SQLITE_ERROR if any of the following are true: 7167** <ul> 7168** <li> ^(Database zDb does not exist)^, 7169** <li> ^(Table zTable does not exist within database zDb)^, 7170** <li> ^(Table zTable is a WITHOUT ROWID table)^, 7171** <li> ^(Column zColumn does not exist)^, 7172** <li> ^(Row iRow is not present in the table)^, 7173** <li> ^(The specified column of row iRow contains a value that is not 7174** a TEXT or BLOB value)^, 7175** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 7176** constraint and the blob is being opened for read/write access)^, 7177** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 7178** column zColumn is part of a [child key] definition and the blob is 7179** being opened for read/write access)^. 7180** </ul> 7181** 7182** ^Unless it returns SQLITE_MISUSE, this function sets the 7183** [database connection] error code and message accessible via 7184** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7185** 7186** A BLOB referenced by sqlite3_blob_open() may be read using the 7187** [sqlite3_blob_read()] interface and modified by using 7188** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 7189** different row of the same table using the [sqlite3_blob_reopen()] 7190** interface. However, the column, table, or database of a [BLOB handle] 7191** cannot be changed after the [BLOB handle] is opened. 7192** 7193** ^(If the row that a BLOB handle points to is modified by an 7194** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 7195** then the BLOB handle is marked as "expired". 7196** This is true if any column of the row is changed, even a column 7197** other than the one the BLOB handle is open on.)^ 7198** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 7199** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 7200** ^(Changes written into a BLOB prior to the BLOB expiring are not 7201** rolled back by the expiration of the BLOB. Such changes will eventually 7202** commit if the transaction continues to completion.)^ 7203** 7204** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 7205** the opened blob. ^The size of a blob may not be changed by this 7206** interface. Use the [UPDATE] SQL command to change the size of a 7207** blob. 7208** 7209** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 7210** and the built-in [zeroblob] SQL function may be used to create a 7211** zero-filled blob to read or write using the incremental-blob interface. 7212** 7213** To avoid a resource leak, every open [BLOB handle] should eventually 7214** be released by a call to [sqlite3_blob_close()]. 7215** 7216** See also: [sqlite3_blob_close()], 7217** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 7218** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 7219*/ 7220int sqlite3_blob_open( 7221 sqlite3*, 7222 const char *zDb, 7223 const char *zTable, 7224 const char *zColumn, 7225 sqlite3_int64 iRow, 7226 int flags, 7227 sqlite3_blob **ppBlob 7228); 7229 7230/* 7231** CAPI3REF: Move a BLOB Handle to a New Row 7232** METHOD: sqlite3_blob 7233** 7234** ^This function is used to move an existing [BLOB handle] so that it points 7235** to a different row of the same database table. ^The new row is identified 7236** by the rowid value passed as the second argument. Only the row can be 7237** changed. ^The database, table and column on which the blob handle is open 7238** remain the same. Moving an existing [BLOB handle] to a new row is 7239** faster than closing the existing handle and opening a new one. 7240** 7241** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 7242** it must exist and there must be either a blob or text value stored in 7243** the nominated column.)^ ^If the new row is not present in the table, or if 7244** it does not contain a blob or text value, or if another error occurs, an 7245** SQLite error code is returned and the blob handle is considered aborted. 7246** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 7247** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 7248** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 7249** always returns zero. 7250** 7251** ^This function sets the database handle error code and message. 7252*/ 7253int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 7254 7255/* 7256** CAPI3REF: Close A BLOB Handle 7257** DESTRUCTOR: sqlite3_blob 7258** 7259** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 7260** unconditionally. Even if this routine returns an error code, the 7261** handle is still closed.)^ 7262** 7263** ^If the blob handle being closed was opened for read-write access, and if 7264** the database is in auto-commit mode and there are no other open read-write 7265** blob handles or active write statements, the current transaction is 7266** committed. ^If an error occurs while committing the transaction, an error 7267** code is returned and the transaction rolled back. 7268** 7269** Calling this function with an argument that is not a NULL pointer or an 7270** open blob handle results in undefined behaviour. ^Calling this routine 7271** with a null pointer (such as would be returned by a failed call to 7272** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 7273** is passed a valid open blob handle, the values returned by the 7274** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 7275*/ 7276int sqlite3_blob_close(sqlite3_blob *); 7277 7278/* 7279** CAPI3REF: Return The Size Of An Open BLOB 7280** METHOD: sqlite3_blob 7281** 7282** ^Returns the size in bytes of the BLOB accessible via the 7283** successfully opened [BLOB handle] in its only argument. ^The 7284** incremental blob I/O routines can only read or overwriting existing 7285** blob content; they cannot change the size of a blob. 7286** 7287** This routine only works on a [BLOB handle] which has been created 7288** by a prior successful call to [sqlite3_blob_open()] and which has not 7289** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7290** to this routine results in undefined and probably undesirable behavior. 7291*/ 7292int sqlite3_blob_bytes(sqlite3_blob *); 7293 7294/* 7295** CAPI3REF: Read Data From A BLOB Incrementally 7296** METHOD: sqlite3_blob 7297** 7298** ^(This function is used to read data from an open [BLOB handle] into a 7299** caller-supplied buffer. N bytes of data are copied into buffer Z 7300** from the open BLOB, starting at offset iOffset.)^ 7301** 7302** ^If offset iOffset is less than N bytes from the end of the BLOB, 7303** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 7304** less than zero, [SQLITE_ERROR] is returned and no data is read. 7305** ^The size of the blob (and hence the maximum value of N+iOffset) 7306** can be determined using the [sqlite3_blob_bytes()] interface. 7307** 7308** ^An attempt to read from an expired [BLOB handle] fails with an 7309** error code of [SQLITE_ABORT]. 7310** 7311** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 7312** Otherwise, an [error code] or an [extended error code] is returned.)^ 7313** 7314** This routine only works on a [BLOB handle] which has been created 7315** by a prior successful call to [sqlite3_blob_open()] and which has not 7316** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7317** to this routine results in undefined and probably undesirable behavior. 7318** 7319** See also: [sqlite3_blob_write()]. 7320*/ 7321int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 7322 7323/* 7324** CAPI3REF: Write Data Into A BLOB Incrementally 7325** METHOD: sqlite3_blob 7326** 7327** ^(This function is used to write data into an open [BLOB handle] from a 7328** caller-supplied buffer. N bytes of data are copied from the buffer Z 7329** into the open BLOB, starting at offset iOffset.)^ 7330** 7331** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 7332** Otherwise, an [error code] or an [extended error code] is returned.)^ 7333** ^Unless SQLITE_MISUSE is returned, this function sets the 7334** [database connection] error code and message accessible via 7335** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7336** 7337** ^If the [BLOB handle] passed as the first argument was not opened for 7338** writing (the flags parameter to [sqlite3_blob_open()] was zero), 7339** this function returns [SQLITE_READONLY]. 7340** 7341** This function may only modify the contents of the BLOB; it is 7342** not possible to increase the size of a BLOB using this API. 7343** ^If offset iOffset is less than N bytes from the end of the BLOB, 7344** [SQLITE_ERROR] is returned and no data is written. The size of the 7345** BLOB (and hence the maximum value of N+iOffset) can be determined 7346** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 7347** than zero [SQLITE_ERROR] is returned and no data is written. 7348** 7349** ^An attempt to write to an expired [BLOB handle] fails with an 7350** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 7351** before the [BLOB handle] expired are not rolled back by the 7352** expiration of the handle, though of course those changes might 7353** have been overwritten by the statement that expired the BLOB handle 7354** or by other independent statements. 7355** 7356** This routine only works on a [BLOB handle] which has been created 7357** by a prior successful call to [sqlite3_blob_open()] and which has not 7358** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7359** to this routine results in undefined and probably undesirable behavior. 7360** 7361** See also: [sqlite3_blob_read()]. 7362*/ 7363int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 7364 7365/* 7366** CAPI3REF: Virtual File System Objects 7367** 7368** A virtual filesystem (VFS) is an [sqlite3_vfs] object 7369** that SQLite uses to interact 7370** with the underlying operating system. Most SQLite builds come with a 7371** single default VFS that is appropriate for the host computer. 7372** New VFSes can be registered and existing VFSes can be unregistered. 7373** The following interfaces are provided. 7374** 7375** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 7376** ^Names are case sensitive. 7377** ^Names are zero-terminated UTF-8 strings. 7378** ^If there is no match, a NULL pointer is returned. 7379** ^If zVfsName is NULL then the default VFS is returned. 7380** 7381** ^New VFSes are registered with sqlite3_vfs_register(). 7382** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 7383** ^The same VFS can be registered multiple times without injury. 7384** ^To make an existing VFS into the default VFS, register it again 7385** with the makeDflt flag set. If two different VFSes with the 7386** same name are registered, the behavior is undefined. If a 7387** VFS is registered with a name that is NULL or an empty string, 7388** then the behavior is undefined. 7389** 7390** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 7391** ^(If the default VFS is unregistered, another VFS is chosen as 7392** the default. The choice for the new VFS is arbitrary.)^ 7393*/ 7394sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 7395int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 7396int sqlite3_vfs_unregister(sqlite3_vfs*); 7397 7398/* 7399** CAPI3REF: Mutexes 7400** 7401** The SQLite core uses these routines for thread 7402** synchronization. Though they are intended for internal 7403** use by SQLite, code that links against SQLite is 7404** permitted to use any of these routines. 7405** 7406** The SQLite source code contains multiple implementations 7407** of these mutex routines. An appropriate implementation 7408** is selected automatically at compile-time. The following 7409** implementations are available in the SQLite core: 7410** 7411** <ul> 7412** <li> SQLITE_MUTEX_PTHREADS 7413** <li> SQLITE_MUTEX_W32 7414** <li> SQLITE_MUTEX_NOOP 7415** </ul> 7416** 7417** The SQLITE_MUTEX_NOOP implementation is a set of routines 7418** that does no real locking and is appropriate for use in 7419** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 7420** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 7421** and Windows. 7422** 7423** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 7424** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 7425** implementation is included with the library. In this case the 7426** application must supply a custom mutex implementation using the 7427** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 7428** before calling sqlite3_initialize() or any other public sqlite3_ 7429** function that calls sqlite3_initialize(). 7430** 7431** ^The sqlite3_mutex_alloc() routine allocates a new 7432** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 7433** routine returns NULL if it is unable to allocate the requested 7434** mutex. The argument to sqlite3_mutex_alloc() must one of these 7435** integer constants: 7436** 7437** <ul> 7438** <li> SQLITE_MUTEX_FAST 7439** <li> SQLITE_MUTEX_RECURSIVE 7440** <li> SQLITE_MUTEX_STATIC_MAIN 7441** <li> SQLITE_MUTEX_STATIC_MEM 7442** <li> SQLITE_MUTEX_STATIC_OPEN 7443** <li> SQLITE_MUTEX_STATIC_PRNG 7444** <li> SQLITE_MUTEX_STATIC_LRU 7445** <li> SQLITE_MUTEX_STATIC_PMEM 7446** <li> SQLITE_MUTEX_STATIC_APP1 7447** <li> SQLITE_MUTEX_STATIC_APP2 7448** <li> SQLITE_MUTEX_STATIC_APP3 7449** <li> SQLITE_MUTEX_STATIC_VFS1 7450** <li> SQLITE_MUTEX_STATIC_VFS2 7451** <li> SQLITE_MUTEX_STATIC_VFS3 7452** </ul> 7453** 7454** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 7455** cause sqlite3_mutex_alloc() to create 7456** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 7457** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 7458** The mutex implementation does not need to make a distinction 7459** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 7460** not want to. SQLite will only request a recursive mutex in 7461** cases where it really needs one. If a faster non-recursive mutex 7462** implementation is available on the host platform, the mutex subsystem 7463** might return such a mutex in response to SQLITE_MUTEX_FAST. 7464** 7465** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 7466** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 7467** a pointer to a static preexisting mutex. ^Nine static mutexes are 7468** used by the current version of SQLite. Future versions of SQLite 7469** may add additional static mutexes. Static mutexes are for internal 7470** use by SQLite only. Applications that use SQLite mutexes should 7471** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 7472** SQLITE_MUTEX_RECURSIVE. 7473** 7474** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 7475** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 7476** returns a different mutex on every call. ^For the static 7477** mutex types, the same mutex is returned on every call that has 7478** the same type number. 7479** 7480** ^The sqlite3_mutex_free() routine deallocates a previously 7481** allocated dynamic mutex. Attempting to deallocate a static 7482** mutex results in undefined behavior. 7483** 7484** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 7485** to enter a mutex. ^If another thread is already within the mutex, 7486** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 7487** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 7488** upon successful entry. ^(Mutexes created using 7489** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 7490** In such cases, the 7491** mutex must be exited an equal number of times before another thread 7492** can enter.)^ If the same thread tries to enter any mutex other 7493** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 7494** 7495** ^(Some systems (for example, Windows 95) do not support the operation 7496** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 7497** will always return SQLITE_BUSY. The SQLite core only ever uses 7498** sqlite3_mutex_try() as an optimization so this is acceptable 7499** behavior.)^ 7500** 7501** ^The sqlite3_mutex_leave() routine exits a mutex that was 7502** previously entered by the same thread. The behavior 7503** is undefined if the mutex is not currently entered by the 7504** calling thread or is not currently allocated. 7505** 7506** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 7507** sqlite3_mutex_leave() is a NULL pointer, then all three routines 7508** behave as no-ops. 7509** 7510** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 7511*/ 7512sqlite3_mutex *sqlite3_mutex_alloc(int); 7513void sqlite3_mutex_free(sqlite3_mutex*); 7514void sqlite3_mutex_enter(sqlite3_mutex*); 7515int sqlite3_mutex_try(sqlite3_mutex*); 7516void sqlite3_mutex_leave(sqlite3_mutex*); 7517 7518/* 7519** CAPI3REF: Mutex Methods Object 7520** 7521** An instance of this structure defines the low-level routines 7522** used to allocate and use mutexes. 7523** 7524** Usually, the default mutex implementations provided by SQLite are 7525** sufficient, however the application has the option of substituting a custom 7526** implementation for specialized deployments or systems for which SQLite 7527** does not provide a suitable implementation. In this case, the application 7528** creates and populates an instance of this structure to pass 7529** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 7530** Additionally, an instance of this structure can be used as an 7531** output variable when querying the system for the current mutex 7532** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 7533** 7534** ^The xMutexInit method defined by this structure is invoked as 7535** part of system initialization by the sqlite3_initialize() function. 7536** ^The xMutexInit routine is called by SQLite exactly once for each 7537** effective call to [sqlite3_initialize()]. 7538** 7539** ^The xMutexEnd method defined by this structure is invoked as 7540** part of system shutdown by the sqlite3_shutdown() function. The 7541** implementation of this method is expected to release all outstanding 7542** resources obtained by the mutex methods implementation, especially 7543** those obtained by the xMutexInit method. ^The xMutexEnd() 7544** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 7545** 7546** ^(The remaining seven methods defined by this structure (xMutexAlloc, 7547** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 7548** xMutexNotheld) implement the following interfaces (respectively): 7549** 7550** <ul> 7551** <li> [sqlite3_mutex_alloc()] </li> 7552** <li> [sqlite3_mutex_free()] </li> 7553** <li> [sqlite3_mutex_enter()] </li> 7554** <li> [sqlite3_mutex_try()] </li> 7555** <li> [sqlite3_mutex_leave()] </li> 7556** <li> [sqlite3_mutex_held()] </li> 7557** <li> [sqlite3_mutex_notheld()] </li> 7558** </ul>)^ 7559** 7560** The only difference is that the public sqlite3_XXX functions enumerated 7561** above silently ignore any invocations that pass a NULL pointer instead 7562** of a valid mutex handle. The implementations of the methods defined 7563** by this structure are not required to handle this case. The results 7564** of passing a NULL pointer instead of a valid mutex handle are undefined 7565** (i.e. it is acceptable to provide an implementation that segfaults if 7566** it is passed a NULL pointer). 7567** 7568** The xMutexInit() method must be threadsafe. It must be harmless to 7569** invoke xMutexInit() multiple times within the same process and without 7570** intervening calls to xMutexEnd(). Second and subsequent calls to 7571** xMutexInit() must be no-ops. 7572** 7573** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 7574** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 7575** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 7576** memory allocation for a fast or recursive mutex. 7577** 7578** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 7579** called, but only if the prior call to xMutexInit returned SQLITE_OK. 7580** If xMutexInit fails in any way, it is expected to clean up after itself 7581** prior to returning. 7582*/ 7583typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 7584struct sqlite3_mutex_methods { 7585 int (*xMutexInit)(void); 7586 int (*xMutexEnd)(void); 7587 sqlite3_mutex *(*xMutexAlloc)(int); 7588 void (*xMutexFree)(sqlite3_mutex *); 7589 void (*xMutexEnter)(sqlite3_mutex *); 7590 int (*xMutexTry)(sqlite3_mutex *); 7591 void (*xMutexLeave)(sqlite3_mutex *); 7592 int (*xMutexHeld)(sqlite3_mutex *); 7593 int (*xMutexNotheld)(sqlite3_mutex *); 7594}; 7595 7596/* 7597** CAPI3REF: Mutex Verification Routines 7598** 7599** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 7600** are intended for use inside assert() statements. The SQLite core 7601** never uses these routines except inside an assert() and applications 7602** are advised to follow the lead of the core. The SQLite core only 7603** provides implementations for these routines when it is compiled 7604** with the SQLITE_DEBUG flag. External mutex implementations 7605** are only required to provide these routines if SQLITE_DEBUG is 7606** defined and if NDEBUG is not defined. 7607** 7608** These routines should return true if the mutex in their argument 7609** is held or not held, respectively, by the calling thread. 7610** 7611** The implementation is not required to provide versions of these 7612** routines that actually work. If the implementation does not provide working 7613** versions of these routines, it should at least provide stubs that always 7614** return true so that one does not get spurious assertion failures. 7615** 7616** If the argument to sqlite3_mutex_held() is a NULL pointer then 7617** the routine should return 1. This seems counter-intuitive since 7618** clearly the mutex cannot be held if it does not exist. But 7619** the reason the mutex does not exist is because the build is not 7620** using mutexes. And we do not want the assert() containing the 7621** call to sqlite3_mutex_held() to fail, so a non-zero return is 7622** the appropriate thing to do. The sqlite3_mutex_notheld() 7623** interface should also return 1 when given a NULL pointer. 7624*/ 7625#ifndef NDEBUG 7626int sqlite3_mutex_held(sqlite3_mutex*); 7627int sqlite3_mutex_notheld(sqlite3_mutex*); 7628#endif 7629 7630/* 7631** CAPI3REF: Mutex Types 7632** 7633** The [sqlite3_mutex_alloc()] interface takes a single argument 7634** which is one of these integer constants. 7635** 7636** The set of static mutexes may change from one SQLite release to the 7637** next. Applications that override the built-in mutex logic must be 7638** prepared to accommodate additional static mutexes. 7639*/ 7640#define SQLITE_MUTEX_FAST 0 7641#define SQLITE_MUTEX_RECURSIVE 1 7642#define SQLITE_MUTEX_STATIC_MAIN 2 7643#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 7644#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 7645#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 7646#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 7647#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 7648#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 7649#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 7650#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 7651#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 7652#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 7653#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 7654#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 7655#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 7656 7657/* Legacy compatibility: */ 7658#define SQLITE_MUTEX_STATIC_MASTER 2 7659 7660 7661/* 7662** CAPI3REF: Retrieve the mutex for a database connection 7663** METHOD: sqlite3 7664** 7665** ^This interface returns a pointer the [sqlite3_mutex] object that 7666** serializes access to the [database connection] given in the argument 7667** when the [threading mode] is Serialized. 7668** ^If the [threading mode] is Single-thread or Multi-thread then this 7669** routine returns a NULL pointer. 7670*/ 7671sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 7672 7673/* 7674** CAPI3REF: Low-Level Control Of Database Files 7675** METHOD: sqlite3 7676** KEYWORDS: {file control} 7677** 7678** ^The [sqlite3_file_control()] interface makes a direct call to the 7679** xFileControl method for the [sqlite3_io_methods] object associated 7680** with a particular database identified by the second argument. ^The 7681** name of the database is "main" for the main database or "temp" for the 7682** TEMP database, or the name that appears after the AS keyword for 7683** databases that are added using the [ATTACH] SQL command. 7684** ^A NULL pointer can be used in place of "main" to refer to the 7685** main database file. 7686** ^The third and fourth parameters to this routine 7687** are passed directly through to the second and third parameters of 7688** the xFileControl method. ^The return value of the xFileControl 7689** method becomes the return value of this routine. 7690** 7691** A few opcodes for [sqlite3_file_control()] are handled directly 7692** by the SQLite core and never invoke the 7693** sqlite3_io_methods.xFileControl method. 7694** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 7695** a pointer to the underlying [sqlite3_file] object to be written into 7696** the space pointed to by the 4th parameter. The 7697** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns 7698** the [sqlite3_file] object associated with the journal file instead of 7699** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns 7700** a pointer to the underlying [sqlite3_vfs] object for the file. 7701** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter 7702** from the pager. 7703** 7704** ^If the second parameter (zDbName) does not match the name of any 7705** open database file, then SQLITE_ERROR is returned. ^This error 7706** code is not remembered and will not be recalled by [sqlite3_errcode()] 7707** or [sqlite3_errmsg()]. The underlying xFileControl method might 7708** also return SQLITE_ERROR. There is no way to distinguish between 7709** an incorrect zDbName and an SQLITE_ERROR return from the underlying 7710** xFileControl method. 7711** 7712** See also: [file control opcodes] 7713*/ 7714int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 7715 7716/* 7717** CAPI3REF: Testing Interface 7718** 7719** ^The sqlite3_test_control() interface is used to read out internal 7720** state of SQLite and to inject faults into SQLite for testing 7721** purposes. ^The first parameter is an operation code that determines 7722** the number, meaning, and operation of all subsequent parameters. 7723** 7724** This interface is not for use by applications. It exists solely 7725** for verifying the correct operation of the SQLite library. Depending 7726** on how the SQLite library is compiled, this interface might not exist. 7727** 7728** The details of the operation codes, their meanings, the parameters 7729** they take, and what they do are all subject to change without notice. 7730** Unlike most of the SQLite API, this function is not guaranteed to 7731** operate consistently from one release to the next. 7732*/ 7733int sqlite3_test_control(int op, ...); 7734 7735/* 7736** CAPI3REF: Testing Interface Operation Codes 7737** 7738** These constants are the valid operation code parameters used 7739** as the first argument to [sqlite3_test_control()]. 7740** 7741** These parameters and their meanings are subject to change 7742** without notice. These values are for testing purposes only. 7743** Applications should not use any of these parameters or the 7744** [sqlite3_test_control()] interface. 7745*/ 7746#define SQLITE_TESTCTRL_FIRST 5 7747#define SQLITE_TESTCTRL_PRNG_SAVE 5 7748#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7749#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */ 7750#define SQLITE_TESTCTRL_BITVEC_TEST 8 7751#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7752#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7753#define SQLITE_TESTCTRL_PENDING_BYTE 11 7754#define SQLITE_TESTCTRL_ASSERT 12 7755#define SQLITE_TESTCTRL_ALWAYS 13 7756#define SQLITE_TESTCTRL_RESERVE 14 /* NOT USED */ 7757#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7758#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */ 7759#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7760#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17 7761#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7762#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7763#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7764#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7765#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7766#define SQLITE_TESTCTRL_BYTEORDER 22 7767#define SQLITE_TESTCTRL_ISINIT 23 7768#define SQLITE_TESTCTRL_SORTER_MMAP 24 7769#define SQLITE_TESTCTRL_IMPOSTER 25 7770#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7771#define SQLITE_TESTCTRL_RESULT_INTREAL 27 7772#define SQLITE_TESTCTRL_PRNG_SEED 28 7773#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29 7774#define SQLITE_TESTCTRL_SEEK_COUNT 30 7775#define SQLITE_TESTCTRL_TRACEFLAGS 31 7776#define SQLITE_TESTCTRL_LAST 31 /* Largest TESTCTRL */ 7777 7778/* 7779** CAPI3REF: SQL Keyword Checking 7780** 7781** These routines provide access to the set of SQL language keywords 7782** recognized by SQLite. Applications can uses these routines to determine 7783** whether or not a specific identifier needs to be escaped (for example, 7784** by enclosing in double-quotes) so as not to confuse the parser. 7785** 7786** The sqlite3_keyword_count() interface returns the number of distinct 7787** keywords understood by SQLite. 7788** 7789** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and 7790** makes *Z point to that keyword expressed as UTF8 and writes the number 7791** of bytes in the keyword into *L. The string that *Z points to is not 7792** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns 7793** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z 7794** or L are NULL or invalid pointers then calls to 7795** sqlite3_keyword_name(N,Z,L) result in undefined behavior. 7796** 7797** The sqlite3_keyword_check(Z,L) interface checks to see whether or not 7798** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero 7799** if it is and zero if not. 7800** 7801** The parser used by SQLite is forgiving. It is often possible to use 7802** a keyword as an identifier as long as such use does not result in a 7803** parsing ambiguity. For example, the statement 7804** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and 7805** creates a new table named "BEGIN" with three columns named 7806** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid 7807** using keywords as identifiers. Common techniques used to avoid keyword 7808** name collisions include: 7809** <ul> 7810** <li> Put all identifier names inside double-quotes. This is the official 7811** SQL way to escape identifier names. 7812** <li> Put identifier names inside [...]. This is not standard SQL, 7813** but it is what SQL Server does and so lots of programmers use this 7814** technique. 7815** <li> Begin every identifier with the letter "Z" as no SQL keywords start 7816** with "Z". 7817** <li> Include a digit somewhere in every identifier name. 7818** </ul> 7819** 7820** Note that the number of keywords understood by SQLite can depend on 7821** compile-time options. For example, "VACUUM" is not a keyword if 7822** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also, 7823** new keywords may be added to future releases of SQLite. 7824*/ 7825int sqlite3_keyword_count(void); 7826int sqlite3_keyword_name(int,const char**,int*); 7827int sqlite3_keyword_check(const char*,int); 7828 7829/* 7830** CAPI3REF: Dynamic String Object 7831** KEYWORDS: {dynamic string} 7832** 7833** An instance of the sqlite3_str object contains a dynamically-sized 7834** string under construction. 7835** 7836** The lifecycle of an sqlite3_str object is as follows: 7837** <ol> 7838** <li> ^The sqlite3_str object is created using [sqlite3_str_new()]. 7839** <li> ^Text is appended to the sqlite3_str object using various 7840** methods, such as [sqlite3_str_appendf()]. 7841** <li> ^The sqlite3_str object is destroyed and the string it created 7842** is returned using the [sqlite3_str_finish()] interface. 7843** </ol> 7844*/ 7845typedef struct sqlite3_str sqlite3_str; 7846 7847/* 7848** CAPI3REF: Create A New Dynamic String Object 7849** CONSTRUCTOR: sqlite3_str 7850** 7851** ^The [sqlite3_str_new(D)] interface allocates and initializes 7852** a new [sqlite3_str] object. To avoid memory leaks, the object returned by 7853** [sqlite3_str_new()] must be freed by a subsequent call to 7854** [sqlite3_str_finish(X)]. 7855** 7856** ^The [sqlite3_str_new(D)] interface always returns a pointer to a 7857** valid [sqlite3_str] object, though in the event of an out-of-memory 7858** error the returned object might be a special singleton that will 7859** silently reject new text, always return SQLITE_NOMEM from 7860** [sqlite3_str_errcode()], always return 0 for 7861** [sqlite3_str_length()], and always return NULL from 7862** [sqlite3_str_finish(X)]. It is always safe to use the value 7863** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter 7864** to any of the other [sqlite3_str] methods. 7865** 7866** The D parameter to [sqlite3_str_new(D)] may be NULL. If the 7867** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum 7868** length of the string contained in the [sqlite3_str] object will be 7869** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead 7870** of [SQLITE_MAX_LENGTH]. 7871*/ 7872sqlite3_str *sqlite3_str_new(sqlite3*); 7873 7874/* 7875** CAPI3REF: Finalize A Dynamic String 7876** DESTRUCTOR: sqlite3_str 7877** 7878** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X 7879** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()] 7880** that contains the constructed string. The calling application should 7881** pass the returned value to [sqlite3_free()] to avoid a memory leak. 7882** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any 7883** errors were encountered during construction of the string. ^The 7884** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the 7885** string in [sqlite3_str] object X is zero bytes long. 7886*/ 7887char *sqlite3_str_finish(sqlite3_str*); 7888 7889/* 7890** CAPI3REF: Add Content To A Dynamic String 7891** METHOD: sqlite3_str 7892** 7893** These interfaces add content to an sqlite3_str object previously obtained 7894** from [sqlite3_str_new()]. 7895** 7896** ^The [sqlite3_str_appendf(X,F,...)] and 7897** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf] 7898** functionality of SQLite to append formatted text onto the end of 7899** [sqlite3_str] object X. 7900** 7901** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S 7902** onto the end of the [sqlite3_str] object X. N must be non-negative. 7903** S must contain at least N non-zero bytes of content. To append a 7904** zero-terminated string in its entirety, use the [sqlite3_str_appendall()] 7905** method instead. 7906** 7907** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of 7908** zero-terminated string S onto the end of [sqlite3_str] object X. 7909** 7910** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the 7911** single-byte character C onto the end of [sqlite3_str] object X. 7912** ^This method can be used, for example, to add whitespace indentation. 7913** 7914** ^The [sqlite3_str_reset(X)] method resets the string under construction 7915** inside [sqlite3_str] object X back to zero bytes in length. 7916** 7917** These methods do not return a result code. ^If an error occurs, that fact 7918** is recorded in the [sqlite3_str] object and can be recovered by a 7919** subsequent call to [sqlite3_str_errcode(X)]. 7920*/ 7921void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...); 7922void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list); 7923void sqlite3_str_append(sqlite3_str*, const char *zIn, int N); 7924void sqlite3_str_appendall(sqlite3_str*, const char *zIn); 7925void sqlite3_str_appendchar(sqlite3_str*, int N, char C); 7926void sqlite3_str_reset(sqlite3_str*); 7927 7928/* 7929** CAPI3REF: Status Of A Dynamic String 7930** METHOD: sqlite3_str 7931** 7932** These interfaces return the current status of an [sqlite3_str] object. 7933** 7934** ^If any prior errors have occurred while constructing the dynamic string 7935** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return 7936** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns 7937** [SQLITE_NOMEM] following any out-of-memory error, or 7938** [SQLITE_TOOBIG] if the size of the dynamic string exceeds 7939** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors. 7940** 7941** ^The [sqlite3_str_length(X)] method returns the current length, in bytes, 7942** of the dynamic string under construction in [sqlite3_str] object X. 7943** ^The length returned by [sqlite3_str_length(X)] does not include the 7944** zero-termination byte. 7945** 7946** ^The [sqlite3_str_value(X)] method returns a pointer to the current 7947** content of the dynamic string under construction in X. The value 7948** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X 7949** and might be freed or altered by any subsequent method on the same 7950** [sqlite3_str] object. Applications must not used the pointer returned 7951** [sqlite3_str_value(X)] after any subsequent method call on the same 7952** object. ^Applications may change the content of the string returned 7953** by [sqlite3_str_value(X)] as long as they do not write into any bytes 7954** outside the range of 0 to [sqlite3_str_length(X)] and do not read or 7955** write any byte after any subsequent sqlite3_str method call. 7956*/ 7957int sqlite3_str_errcode(sqlite3_str*); 7958int sqlite3_str_length(sqlite3_str*); 7959char *sqlite3_str_value(sqlite3_str*); 7960 7961/* 7962** CAPI3REF: SQLite Runtime Status 7963** 7964** ^These interfaces are used to retrieve runtime status information 7965** about the performance of SQLite, and optionally to reset various 7966** highwater marks. ^The first argument is an integer code for 7967** the specific parameter to measure. ^(Recognized integer codes 7968** are of the form [status parameters | SQLITE_STATUS_...].)^ 7969** ^The current value of the parameter is returned into *pCurrent. 7970** ^The highest recorded value is returned in *pHighwater. ^If the 7971** resetFlag is true, then the highest record value is reset after 7972** *pHighwater is written. ^(Some parameters do not record the highest 7973** value. For those parameters 7974** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7975** ^(Other parameters record only the highwater mark and not the current 7976** value. For these latter parameters nothing is written into *pCurrent.)^ 7977** 7978** ^The sqlite3_status() and sqlite3_status64() routines return 7979** SQLITE_OK on success and a non-zero [error code] on failure. 7980** 7981** If either the current value or the highwater mark is too large to 7982** be represented by a 32-bit integer, then the values returned by 7983** sqlite3_status() are undefined. 7984** 7985** See also: [sqlite3_db_status()] 7986*/ 7987int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7988int sqlite3_status64( 7989 int op, 7990 sqlite3_int64 *pCurrent, 7991 sqlite3_int64 *pHighwater, 7992 int resetFlag 7993); 7994 7995 7996/* 7997** CAPI3REF: Status Parameters 7998** KEYWORDS: {status parameters} 7999** 8000** These integer constants designate various run-time status parameters 8001** that can be returned by [sqlite3_status()]. 8002** 8003** <dl> 8004** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 8005** <dd>This parameter is the current amount of memory checked out 8006** using [sqlite3_malloc()], either directly or indirectly. The 8007** figure includes calls made to [sqlite3_malloc()] by the application 8008** and internal memory usage by the SQLite library. Auxiliary page-cache 8009** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 8010** this parameter. The amount returned is the sum of the allocation 8011** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 8012** 8013** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 8014** <dd>This parameter records the largest memory allocation request 8015** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 8016** internal equivalents). Only the value returned in the 8017** *pHighwater parameter to [sqlite3_status()] is of interest. 8018** The value written into the *pCurrent parameter is undefined.</dd>)^ 8019** 8020** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 8021** <dd>This parameter records the number of separate memory allocations 8022** currently checked out.</dd>)^ 8023** 8024** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 8025** <dd>This parameter returns the number of pages used out of the 8026** [pagecache memory allocator] that was configured using 8027** [SQLITE_CONFIG_PAGECACHE]. The 8028** value returned is in pages, not in bytes.</dd>)^ 8029** 8030** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 8031** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 8032** <dd>This parameter returns the number of bytes of page cache 8033** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 8034** buffer and where forced to overflow to [sqlite3_malloc()]. The 8035** returned value includes allocations that overflowed because they 8036** where too large (they were larger than the "sz" parameter to 8037** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 8038** no space was left in the page cache.</dd>)^ 8039** 8040** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 8041** <dd>This parameter records the largest memory allocation request 8042** handed to the [pagecache memory allocator]. Only the value returned in the 8043** *pHighwater parameter to [sqlite3_status()] is of interest. 8044** The value written into the *pCurrent parameter is undefined.</dd>)^ 8045** 8046** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 8047** <dd>No longer used.</dd> 8048** 8049** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 8050** <dd>No longer used.</dd> 8051** 8052** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 8053** <dd>No longer used.</dd> 8054** 8055** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 8056** <dd>The *pHighwater parameter records the deepest parser stack. 8057** The *pCurrent value is undefined. The *pHighwater value is only 8058** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 8059** </dl> 8060** 8061** New status parameters may be added from time to time. 8062*/ 8063#define SQLITE_STATUS_MEMORY_USED 0 8064#define SQLITE_STATUS_PAGECACHE_USED 1 8065#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 8066#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 8067#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 8068#define SQLITE_STATUS_MALLOC_SIZE 5 8069#define SQLITE_STATUS_PARSER_STACK 6 8070#define SQLITE_STATUS_PAGECACHE_SIZE 7 8071#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 8072#define SQLITE_STATUS_MALLOC_COUNT 9 8073 8074/* 8075** CAPI3REF: Database Connection Status 8076** METHOD: sqlite3 8077** 8078** ^This interface is used to retrieve runtime status information 8079** about a single [database connection]. ^The first argument is the 8080** database connection object to be interrogated. ^The second argument 8081** is an integer constant, taken from the set of 8082** [SQLITE_DBSTATUS options], that 8083** determines the parameter to interrogate. The set of 8084** [SQLITE_DBSTATUS options] is likely 8085** to grow in future releases of SQLite. 8086** 8087** ^The current value of the requested parameter is written into *pCur 8088** and the highest instantaneous value is written into *pHiwtr. ^If 8089** the resetFlg is true, then the highest instantaneous value is 8090** reset back down to the current value. 8091** 8092** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 8093** non-zero [error code] on failure. 8094** 8095** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 8096*/ 8097int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 8098 8099/* 8100** CAPI3REF: Status Parameters for database connections 8101** KEYWORDS: {SQLITE_DBSTATUS options} 8102** 8103** These constants are the available integer "verbs" that can be passed as 8104** the second argument to the [sqlite3_db_status()] interface. 8105** 8106** New verbs may be added in future releases of SQLite. Existing verbs 8107** might be discontinued. Applications should check the return code from 8108** [sqlite3_db_status()] to make sure that the call worked. 8109** The [sqlite3_db_status()] interface will return a non-zero error code 8110** if a discontinued or unsupported verb is invoked. 8111** 8112** <dl> 8113** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 8114** <dd>This parameter returns the number of lookaside memory slots currently 8115** checked out.</dd>)^ 8116** 8117** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 8118** <dd>This parameter returns the number of malloc attempts that were 8119** satisfied using lookaside memory. Only the high-water value is meaningful; 8120** the current value is always zero.)^ 8121** 8122** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 8123** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 8124** <dd>This parameter returns the number malloc attempts that might have 8125** been satisfied using lookaside memory but failed due to the amount of 8126** memory requested being larger than the lookaside slot size. 8127** Only the high-water value is meaningful; 8128** the current value is always zero.)^ 8129** 8130** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 8131** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 8132** <dd>This parameter returns the number malloc attempts that might have 8133** been satisfied using lookaside memory but failed due to all lookaside 8134** memory already being in use. 8135** Only the high-water value is meaningful; 8136** the current value is always zero.)^ 8137** 8138** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 8139** <dd>This parameter returns the approximate number of bytes of heap 8140** memory used by all pager caches associated with the database connection.)^ 8141** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 8142** 8143** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 8144** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 8145** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 8146** pager cache is shared between two or more connections the bytes of heap 8147** memory used by that pager cache is divided evenly between the attached 8148** connections.)^ In other words, if none of the pager caches associated 8149** with the database connection are shared, this request returns the same 8150** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 8151** shared, the value returned by this call will be smaller than that returned 8152** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 8153** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 8154** 8155** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 8156** <dd>This parameter returns the approximate number of bytes of heap 8157** memory used to store the schema for all databases associated 8158** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 8159** ^The full amount of memory used by the schemas is reported, even if the 8160** schema memory is shared with other database connections due to 8161** [shared cache mode] being enabled. 8162** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 8163** 8164** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 8165** <dd>This parameter returns the approximate number of bytes of heap 8166** and lookaside memory used by all prepared statements associated with 8167** the database connection.)^ 8168** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 8169** </dd> 8170** 8171** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 8172** <dd>This parameter returns the number of pager cache hits that have 8173** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 8174** is always 0. 8175** </dd> 8176** 8177** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 8178** <dd>This parameter returns the number of pager cache misses that have 8179** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 8180** is always 0. 8181** </dd> 8182** 8183** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 8184** <dd>This parameter returns the number of dirty cache entries that have 8185** been written to disk. Specifically, the number of pages written to the 8186** wal file in wal mode databases, or the number of pages written to the 8187** database file in rollback mode databases. Any pages written as part of 8188** transaction rollback or database recovery operations are not included. 8189** If an IO or other error occurs while writing a page to disk, the effect 8190** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 8191** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 8192** </dd> 8193** 8194** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 8195** <dd>This parameter returns the number of dirty cache entries that have 8196** been written to disk in the middle of a transaction due to the page 8197** cache overflowing. Transactions are more efficient if they are written 8198** to disk all at once. When pages spill mid-transaction, that introduces 8199** additional overhead. This parameter can be used help identify 8200** inefficiencies that can be resolved by increasing the cache size. 8201** </dd> 8202** 8203** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 8204** <dd>This parameter returns zero for the current value if and only if 8205** all foreign key constraints (deferred or immediate) have been 8206** resolved.)^ ^The highwater mark is always 0. 8207** </dd> 8208** </dl> 8209*/ 8210#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 8211#define SQLITE_DBSTATUS_CACHE_USED 1 8212#define SQLITE_DBSTATUS_SCHEMA_USED 2 8213#define SQLITE_DBSTATUS_STMT_USED 3 8214#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 8215#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 8216#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 8217#define SQLITE_DBSTATUS_CACHE_HIT 7 8218#define SQLITE_DBSTATUS_CACHE_MISS 8 8219#define SQLITE_DBSTATUS_CACHE_WRITE 9 8220#define SQLITE_DBSTATUS_DEFERRED_FKS 10 8221#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 8222#define SQLITE_DBSTATUS_CACHE_SPILL 12 8223#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 8224 8225 8226/* 8227** CAPI3REF: Prepared Statement Status 8228** METHOD: sqlite3_stmt 8229** 8230** ^(Each prepared statement maintains various 8231** [SQLITE_STMTSTATUS counters] that measure the number 8232** of times it has performed specific operations.)^ These counters can 8233** be used to monitor the performance characteristics of the prepared 8234** statements. For example, if the number of table steps greatly exceeds 8235** the number of table searches or result rows, that would tend to indicate 8236** that the prepared statement is using a full table scan rather than 8237** an index. 8238** 8239** ^(This interface is used to retrieve and reset counter values from 8240** a [prepared statement]. The first argument is the prepared statement 8241** object to be interrogated. The second argument 8242** is an integer code for a specific [SQLITE_STMTSTATUS counter] 8243** to be interrogated.)^ 8244** ^The current value of the requested counter is returned. 8245** ^If the resetFlg is true, then the counter is reset to zero after this 8246** interface call returns. 8247** 8248** See also: [sqlite3_status()] and [sqlite3_db_status()]. 8249*/ 8250int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 8251 8252/* 8253** CAPI3REF: Status Parameters for prepared statements 8254** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 8255** 8256** These preprocessor macros define integer codes that name counter 8257** values associated with the [sqlite3_stmt_status()] interface. 8258** The meanings of the various counters are as follows: 8259** 8260** <dl> 8261** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 8262** <dd>^This is the number of times that SQLite has stepped forward in 8263** a table as part of a full table scan. Large numbers for this counter 8264** may indicate opportunities for performance improvement through 8265** careful use of indices.</dd> 8266** 8267** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 8268** <dd>^This is the number of sort operations that have occurred. 8269** A non-zero value in this counter may indicate an opportunity to 8270** improvement performance through careful use of indices.</dd> 8271** 8272** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 8273** <dd>^This is the number of rows inserted into transient indices that 8274** were created automatically in order to help joins run faster. 8275** A non-zero value in this counter may indicate an opportunity to 8276** improvement performance by adding permanent indices that do not 8277** need to be reinitialized each time the statement is run.</dd> 8278** 8279** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 8280** <dd>^This is the number of virtual machine operations executed 8281** by the prepared statement if that number is less than or equal 8282** to 2147483647. The number of virtual machine operations can be 8283** used as a proxy for the total work done by the prepared statement. 8284** If the number of virtual machine operations exceeds 2147483647 8285** then the value returned by this statement status code is undefined. 8286** 8287** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 8288** <dd>^This is the number of times that the prepare statement has been 8289** automatically regenerated due to schema changes or changes to 8290** [bound parameters] that might affect the query plan. 8291** 8292** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 8293** <dd>^This is the number of times that the prepared statement has 8294** been run. A single "run" for the purposes of this counter is one 8295** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 8296** The counter is incremented on the first [sqlite3_step()] call of each 8297** cycle. 8298** 8299** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 8300** <dd>^This is the approximate number of bytes of heap memory 8301** used to store the prepared statement. ^This value is not actually 8302** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 8303** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 8304** </dd> 8305** </dl> 8306*/ 8307#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 8308#define SQLITE_STMTSTATUS_SORT 2 8309#define SQLITE_STMTSTATUS_AUTOINDEX 3 8310#define SQLITE_STMTSTATUS_VM_STEP 4 8311#define SQLITE_STMTSTATUS_REPREPARE 5 8312#define SQLITE_STMTSTATUS_RUN 6 8313#define SQLITE_STMTSTATUS_MEMUSED 99 8314 8315/* 8316** CAPI3REF: Custom Page Cache Object 8317** 8318** The sqlite3_pcache type is opaque. It is implemented by 8319** the pluggable module. The SQLite core has no knowledge of 8320** its size or internal structure and never deals with the 8321** sqlite3_pcache object except by holding and passing pointers 8322** to the object. 8323** 8324** See [sqlite3_pcache_methods2] for additional information. 8325*/ 8326typedef struct sqlite3_pcache sqlite3_pcache; 8327 8328/* 8329** CAPI3REF: Custom Page Cache Object 8330** 8331** The sqlite3_pcache_page object represents a single page in the 8332** page cache. The page cache will allocate instances of this 8333** object. Various methods of the page cache use pointers to instances 8334** of this object as parameters or as their return value. 8335** 8336** See [sqlite3_pcache_methods2] for additional information. 8337*/ 8338typedef struct sqlite3_pcache_page sqlite3_pcache_page; 8339struct sqlite3_pcache_page { 8340 void *pBuf; /* The content of the page */ 8341 void *pExtra; /* Extra information associated with the page */ 8342}; 8343 8344/* 8345** CAPI3REF: Application Defined Page Cache. 8346** KEYWORDS: {page cache} 8347** 8348** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 8349** register an alternative page cache implementation by passing in an 8350** instance of the sqlite3_pcache_methods2 structure.)^ 8351** In many applications, most of the heap memory allocated by 8352** SQLite is used for the page cache. 8353** By implementing a 8354** custom page cache using this API, an application can better control 8355** the amount of memory consumed by SQLite, the way in which 8356** that memory is allocated and released, and the policies used to 8357** determine exactly which parts of a database file are cached and for 8358** how long. 8359** 8360** The alternative page cache mechanism is an 8361** extreme measure that is only needed by the most demanding applications. 8362** The built-in page cache is recommended for most uses. 8363** 8364** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 8365** internal buffer by SQLite within the call to [sqlite3_config]. Hence 8366** the application may discard the parameter after the call to 8367** [sqlite3_config()] returns.)^ 8368** 8369** [[the xInit() page cache method]] 8370** ^(The xInit() method is called once for each effective 8371** call to [sqlite3_initialize()])^ 8372** (usually only once during the lifetime of the process). ^(The xInit() 8373** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 8374** The intent of the xInit() method is to set up global data structures 8375** required by the custom page cache implementation. 8376** ^(If the xInit() method is NULL, then the 8377** built-in default page cache is used instead of the application defined 8378** page cache.)^ 8379** 8380** [[the xShutdown() page cache method]] 8381** ^The xShutdown() method is called by [sqlite3_shutdown()]. 8382** It can be used to clean up 8383** any outstanding resources before process shutdown, if required. 8384** ^The xShutdown() method may be NULL. 8385** 8386** ^SQLite automatically serializes calls to the xInit method, 8387** so the xInit method need not be threadsafe. ^The 8388** xShutdown method is only called from [sqlite3_shutdown()] so it does 8389** not need to be threadsafe either. All other methods must be threadsafe 8390** in multithreaded applications. 8391** 8392** ^SQLite will never invoke xInit() more than once without an intervening 8393** call to xShutdown(). 8394** 8395** [[the xCreate() page cache methods]] 8396** ^SQLite invokes the xCreate() method to construct a new cache instance. 8397** SQLite will typically create one cache instance for each open database file, 8398** though this is not guaranteed. ^The 8399** first parameter, szPage, is the size in bytes of the pages that must 8400** be allocated by the cache. ^szPage will always a power of two. ^The 8401** second parameter szExtra is a number of bytes of extra storage 8402** associated with each page cache entry. ^The szExtra parameter will 8403** a number less than 250. SQLite will use the 8404** extra szExtra bytes on each page to store metadata about the underlying 8405** database page on disk. The value passed into szExtra depends 8406** on the SQLite version, the target platform, and how SQLite was compiled. 8407** ^The third argument to xCreate(), bPurgeable, is true if the cache being 8408** created will be used to cache database pages of a file stored on disk, or 8409** false if it is used for an in-memory database. The cache implementation 8410** does not have to do anything special based with the value of bPurgeable; 8411** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 8412** never invoke xUnpin() except to deliberately delete a page. 8413** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 8414** false will always have the "discard" flag set to true. 8415** ^Hence, a cache created with bPurgeable false will 8416** never contain any unpinned pages. 8417** 8418** [[the xCachesize() page cache method]] 8419** ^(The xCachesize() method may be called at any time by SQLite to set the 8420** suggested maximum cache-size (number of pages stored by) the cache 8421** instance passed as the first argument. This is the value configured using 8422** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 8423** parameter, the implementation is not required to do anything with this 8424** value; it is advisory only. 8425** 8426** [[the xPagecount() page cache methods]] 8427** The xPagecount() method must return the number of pages currently 8428** stored in the cache, both pinned and unpinned. 8429** 8430** [[the xFetch() page cache methods]] 8431** The xFetch() method locates a page in the cache and returns a pointer to 8432** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 8433** The pBuf element of the returned sqlite3_pcache_page object will be a 8434** pointer to a buffer of szPage bytes used to store the content of a 8435** single database page. The pExtra element of sqlite3_pcache_page will be 8436** a pointer to the szExtra bytes of extra storage that SQLite has requested 8437** for each entry in the page cache. 8438** 8439** The page to be fetched is determined by the key. ^The minimum key value 8440** is 1. After it has been retrieved using xFetch, the page is considered 8441** to be "pinned". 8442** 8443** If the requested page is already in the page cache, then the page cache 8444** implementation must return a pointer to the page buffer with its content 8445** intact. If the requested page is not already in the cache, then the 8446** cache implementation should use the value of the createFlag 8447** parameter to help it determined what action to take: 8448** 8449** <table border=1 width=85% align=center> 8450** <tr><th> createFlag <th> Behavior when page is not already in cache 8451** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 8452** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 8453** Otherwise return NULL. 8454** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 8455** NULL if allocating a new page is effectively impossible. 8456** </table> 8457** 8458** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 8459** will only use a createFlag of 2 after a prior call with a createFlag of 1 8460** failed.)^ In between the xFetch() calls, SQLite may 8461** attempt to unpin one or more cache pages by spilling the content of 8462** pinned pages to disk and synching the operating system disk cache. 8463** 8464** [[the xUnpin() page cache method]] 8465** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 8466** as its second argument. If the third parameter, discard, is non-zero, 8467** then the page must be evicted from the cache. 8468** ^If the discard parameter is 8469** zero, then the page may be discarded or retained at the discretion of 8470** page cache implementation. ^The page cache implementation 8471** may choose to evict unpinned pages at any time. 8472** 8473** The cache must not perform any reference counting. A single 8474** call to xUnpin() unpins the page regardless of the number of prior calls 8475** to xFetch(). 8476** 8477** [[the xRekey() page cache methods]] 8478** The xRekey() method is used to change the key value associated with the 8479** page passed as the second argument. If the cache 8480** previously contains an entry associated with newKey, it must be 8481** discarded. ^Any prior cache entry associated with newKey is guaranteed not 8482** to be pinned. 8483** 8484** When SQLite calls the xTruncate() method, the cache must discard all 8485** existing cache entries with page numbers (keys) greater than or equal 8486** to the value of the iLimit parameter passed to xTruncate(). If any 8487** of these pages are pinned, they are implicitly unpinned, meaning that 8488** they can be safely discarded. 8489** 8490** [[the xDestroy() page cache method]] 8491** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 8492** All resources associated with the specified cache should be freed. ^After 8493** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 8494** handle invalid, and will not use it with any other sqlite3_pcache_methods2 8495** functions. 8496** 8497** [[the xShrink() page cache method]] 8498** ^SQLite invokes the xShrink() method when it wants the page cache to 8499** free up as much of heap memory as possible. The page cache implementation 8500** is not obligated to free any memory, but well-behaved implementations should 8501** do their best. 8502*/ 8503typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 8504struct sqlite3_pcache_methods2 { 8505 int iVersion; 8506 void *pArg; 8507 int (*xInit)(void*); 8508 void (*xShutdown)(void*); 8509 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 8510 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8511 int (*xPagecount)(sqlite3_pcache*); 8512 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8513 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 8514 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 8515 unsigned oldKey, unsigned newKey); 8516 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8517 void (*xDestroy)(sqlite3_pcache*); 8518 void (*xShrink)(sqlite3_pcache*); 8519}; 8520 8521/* 8522** This is the obsolete pcache_methods object that has now been replaced 8523** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 8524** retained in the header file for backwards compatibility only. 8525*/ 8526typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 8527struct sqlite3_pcache_methods { 8528 void *pArg; 8529 int (*xInit)(void*); 8530 void (*xShutdown)(void*); 8531 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 8532 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8533 int (*xPagecount)(sqlite3_pcache*); 8534 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8535 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 8536 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 8537 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8538 void (*xDestroy)(sqlite3_pcache*); 8539}; 8540 8541 8542/* 8543** CAPI3REF: Online Backup Object 8544** 8545** The sqlite3_backup object records state information about an ongoing 8546** online backup operation. ^The sqlite3_backup object is created by 8547** a call to [sqlite3_backup_init()] and is destroyed by a call to 8548** [sqlite3_backup_finish()]. 8549** 8550** See Also: [Using the SQLite Online Backup API] 8551*/ 8552typedef struct sqlite3_backup sqlite3_backup; 8553 8554/* 8555** CAPI3REF: Online Backup API. 8556** 8557** The backup API copies the content of one database into another. 8558** It is useful either for creating backups of databases or 8559** for copying in-memory databases to or from persistent files. 8560** 8561** See Also: [Using the SQLite Online Backup API] 8562** 8563** ^SQLite holds a write transaction open on the destination database file 8564** for the duration of the backup operation. 8565** ^The source database is read-locked only while it is being read; 8566** it is not locked continuously for the entire backup operation. 8567** ^Thus, the backup may be performed on a live source database without 8568** preventing other database connections from 8569** reading or writing to the source database while the backup is underway. 8570** 8571** ^(To perform a backup operation: 8572** <ol> 8573** <li><b>sqlite3_backup_init()</b> is called once to initialize the 8574** backup, 8575** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 8576** the data between the two databases, and finally 8577** <li><b>sqlite3_backup_finish()</b> is called to release all resources 8578** associated with the backup operation. 8579** </ol>)^ 8580** There should be exactly one call to sqlite3_backup_finish() for each 8581** successful call to sqlite3_backup_init(). 8582** 8583** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 8584** 8585** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 8586** [database connection] associated with the destination database 8587** and the database name, respectively. 8588** ^The database name is "main" for the main database, "temp" for the 8589** temporary database, or the name specified after the AS keyword in 8590** an [ATTACH] statement for an attached database. 8591** ^The S and M arguments passed to 8592** sqlite3_backup_init(D,N,S,M) identify the [database connection] 8593** and database name of the source database, respectively. 8594** ^The source and destination [database connections] (parameters S and D) 8595** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 8596** an error. 8597** 8598** ^A call to sqlite3_backup_init() will fail, returning NULL, if 8599** there is already a read or read-write transaction open on the 8600** destination database. 8601** 8602** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 8603** returned and an error code and error message are stored in the 8604** destination [database connection] D. 8605** ^The error code and message for the failed call to sqlite3_backup_init() 8606** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 8607** [sqlite3_errmsg16()] functions. 8608** ^A successful call to sqlite3_backup_init() returns a pointer to an 8609** [sqlite3_backup] object. 8610** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 8611** sqlite3_backup_finish() functions to perform the specified backup 8612** operation. 8613** 8614** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 8615** 8616** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 8617** the source and destination databases specified by [sqlite3_backup] object B. 8618** ^If N is negative, all remaining source pages are copied. 8619** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 8620** are still more pages to be copied, then the function returns [SQLITE_OK]. 8621** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 8622** from source to destination, then it returns [SQLITE_DONE]. 8623** ^If an error occurs while running sqlite3_backup_step(B,N), 8624** then an [error code] is returned. ^As well as [SQLITE_OK] and 8625** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 8626** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 8627** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 8628** 8629** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 8630** <ol> 8631** <li> the destination database was opened read-only, or 8632** <li> the destination database is using write-ahead-log journaling 8633** and the destination and source page sizes differ, or 8634** <li> the destination database is an in-memory database and the 8635** destination and source page sizes differ. 8636** </ol>)^ 8637** 8638** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 8639** the [sqlite3_busy_handler | busy-handler function] 8640** is invoked (if one is specified). ^If the 8641** busy-handler returns non-zero before the lock is available, then 8642** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 8643** sqlite3_backup_step() can be retried later. ^If the source 8644** [database connection] 8645** is being used to write to the source database when sqlite3_backup_step() 8646** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 8647** case the call to sqlite3_backup_step() can be retried later on. ^(If 8648** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 8649** [SQLITE_READONLY] is returned, then 8650** there is no point in retrying the call to sqlite3_backup_step(). These 8651** errors are considered fatal.)^ The application must accept 8652** that the backup operation has failed and pass the backup operation handle 8653** to the sqlite3_backup_finish() to release associated resources. 8654** 8655** ^The first call to sqlite3_backup_step() obtains an exclusive lock 8656** on the destination file. ^The exclusive lock is not released until either 8657** sqlite3_backup_finish() is called or the backup operation is complete 8658** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 8659** sqlite3_backup_step() obtains a [shared lock] on the source database that 8660** lasts for the duration of the sqlite3_backup_step() call. 8661** ^Because the source database is not locked between calls to 8662** sqlite3_backup_step(), the source database may be modified mid-way 8663** through the backup process. ^If the source database is modified by an 8664** external process or via a database connection other than the one being 8665** used by the backup operation, then the backup will be automatically 8666** restarted by the next call to sqlite3_backup_step(). ^If the source 8667** database is modified by the using the same database connection as is used 8668** by the backup operation, then the backup database is automatically 8669** updated at the same time. 8670** 8671** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 8672** 8673** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 8674** application wishes to abandon the backup operation, the application 8675** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 8676** ^The sqlite3_backup_finish() interfaces releases all 8677** resources associated with the [sqlite3_backup] object. 8678** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 8679** active write-transaction on the destination database is rolled back. 8680** The [sqlite3_backup] object is invalid 8681** and may not be used following a call to sqlite3_backup_finish(). 8682** 8683** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 8684** sqlite3_backup_step() errors occurred, regardless or whether or not 8685** sqlite3_backup_step() completed. 8686** ^If an out-of-memory condition or IO error occurred during any prior 8687** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 8688** sqlite3_backup_finish() returns the corresponding [error code]. 8689** 8690** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 8691** is not a permanent error and does not affect the return value of 8692** sqlite3_backup_finish(). 8693** 8694** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 8695** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 8696** 8697** ^The sqlite3_backup_remaining() routine returns the number of pages still 8698** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 8699** ^The sqlite3_backup_pagecount() routine returns the total number of pages 8700** in the source database at the conclusion of the most recent 8701** sqlite3_backup_step(). 8702** ^(The values returned by these functions are only updated by 8703** sqlite3_backup_step(). If the source database is modified in a way that 8704** changes the size of the source database or the number of pages remaining, 8705** those changes are not reflected in the output of sqlite3_backup_pagecount() 8706** and sqlite3_backup_remaining() until after the next 8707** sqlite3_backup_step().)^ 8708** 8709** <b>Concurrent Usage of Database Handles</b> 8710** 8711** ^The source [database connection] may be used by the application for other 8712** purposes while a backup operation is underway or being initialized. 8713** ^If SQLite is compiled and configured to support threadsafe database 8714** connections, then the source database connection may be used concurrently 8715** from within other threads. 8716** 8717** However, the application must guarantee that the destination 8718** [database connection] is not passed to any other API (by any thread) after 8719** sqlite3_backup_init() is called and before the corresponding call to 8720** sqlite3_backup_finish(). SQLite does not currently check to see 8721** if the application incorrectly accesses the destination [database connection] 8722** and so no error code is reported, but the operations may malfunction 8723** nevertheless. Use of the destination database connection while a 8724** backup is in progress might also also cause a mutex deadlock. 8725** 8726** If running in [shared cache mode], the application must 8727** guarantee that the shared cache used by the destination database 8728** is not accessed while the backup is running. In practice this means 8729** that the application must guarantee that the disk file being 8730** backed up to is not accessed by any connection within the process, 8731** not just the specific connection that was passed to sqlite3_backup_init(). 8732** 8733** The [sqlite3_backup] object itself is partially threadsafe. Multiple 8734** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 8735** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 8736** APIs are not strictly speaking threadsafe. If they are invoked at the 8737** same time as another thread is invoking sqlite3_backup_step() it is 8738** possible that they return invalid values. 8739*/ 8740sqlite3_backup *sqlite3_backup_init( 8741 sqlite3 *pDest, /* Destination database handle */ 8742 const char *zDestName, /* Destination database name */ 8743 sqlite3 *pSource, /* Source database handle */ 8744 const char *zSourceName /* Source database name */ 8745); 8746int sqlite3_backup_step(sqlite3_backup *p, int nPage); 8747int sqlite3_backup_finish(sqlite3_backup *p); 8748int sqlite3_backup_remaining(sqlite3_backup *p); 8749int sqlite3_backup_pagecount(sqlite3_backup *p); 8750 8751/* 8752** CAPI3REF: Unlock Notification 8753** METHOD: sqlite3 8754** 8755** ^When running in shared-cache mode, a database operation may fail with 8756** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 8757** individual tables within the shared-cache cannot be obtained. See 8758** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 8759** ^This API may be used to register a callback that SQLite will invoke 8760** when the connection currently holding the required lock relinquishes it. 8761** ^This API is only available if the library was compiled with the 8762** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 8763** 8764** See Also: [Using the SQLite Unlock Notification Feature]. 8765** 8766** ^Shared-cache locks are released when a database connection concludes 8767** its current transaction, either by committing it or rolling it back. 8768** 8769** ^When a connection (known as the blocked connection) fails to obtain a 8770** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 8771** identity of the database connection (the blocking connection) that 8772** has locked the required resource is stored internally. ^After an 8773** application receives an SQLITE_LOCKED error, it may call the 8774** sqlite3_unlock_notify() method with the blocked connection handle as 8775** the first argument to register for a callback that will be invoked 8776** when the blocking connections current transaction is concluded. ^The 8777** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 8778** call that concludes the blocking connection's transaction. 8779** 8780** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 8781** there is a chance that the blocking connection will have already 8782** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 8783** If this happens, then the specified callback is invoked immediately, 8784** from within the call to sqlite3_unlock_notify().)^ 8785** 8786** ^If the blocked connection is attempting to obtain a write-lock on a 8787** shared-cache table, and more than one other connection currently holds 8788** a read-lock on the same table, then SQLite arbitrarily selects one of 8789** the other connections to use as the blocking connection. 8790** 8791** ^(There may be at most one unlock-notify callback registered by a 8792** blocked connection. If sqlite3_unlock_notify() is called when the 8793** blocked connection already has a registered unlock-notify callback, 8794** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 8795** called with a NULL pointer as its second argument, then any existing 8796** unlock-notify callback is canceled. ^The blocked connections 8797** unlock-notify callback may also be canceled by closing the blocked 8798** connection using [sqlite3_close()]. 8799** 8800** The unlock-notify callback is not reentrant. If an application invokes 8801** any sqlite3_xxx API functions from within an unlock-notify callback, a 8802** crash or deadlock may be the result. 8803** 8804** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 8805** returns SQLITE_OK. 8806** 8807** <b>Callback Invocation Details</b> 8808** 8809** When an unlock-notify callback is registered, the application provides a 8810** single void* pointer that is passed to the callback when it is invoked. 8811** However, the signature of the callback function allows SQLite to pass 8812** it an array of void* context pointers. The first argument passed to 8813** an unlock-notify callback is a pointer to an array of void* pointers, 8814** and the second is the number of entries in the array. 8815** 8816** When a blocking connection's transaction is concluded, there may be 8817** more than one blocked connection that has registered for an unlock-notify 8818** callback. ^If two or more such blocked connections have specified the 8819** same callback function, then instead of invoking the callback function 8820** multiple times, it is invoked once with the set of void* context pointers 8821** specified by the blocked connections bundled together into an array. 8822** This gives the application an opportunity to prioritize any actions 8823** related to the set of unblocked database connections. 8824** 8825** <b>Deadlock Detection</b> 8826** 8827** Assuming that after registering for an unlock-notify callback a 8828** database waits for the callback to be issued before taking any further 8829** action (a reasonable assumption), then using this API may cause the 8830** application to deadlock. For example, if connection X is waiting for 8831** connection Y's transaction to be concluded, and similarly connection 8832** Y is waiting on connection X's transaction, then neither connection 8833** will proceed and the system may remain deadlocked indefinitely. 8834** 8835** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 8836** detection. ^If a given call to sqlite3_unlock_notify() would put the 8837** system in a deadlocked state, then SQLITE_LOCKED is returned and no 8838** unlock-notify callback is registered. The system is said to be in 8839** a deadlocked state if connection A has registered for an unlock-notify 8840** callback on the conclusion of connection B's transaction, and connection 8841** B has itself registered for an unlock-notify callback when connection 8842** A's transaction is concluded. ^Indirect deadlock is also detected, so 8843** the system is also considered to be deadlocked if connection B has 8844** registered for an unlock-notify callback on the conclusion of connection 8845** C's transaction, where connection C is waiting on connection A. ^Any 8846** number of levels of indirection are allowed. 8847** 8848** <b>The "DROP TABLE" Exception</b> 8849** 8850** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 8851** always appropriate to call sqlite3_unlock_notify(). There is however, 8852** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 8853** SQLite checks if there are any currently executing SELECT statements 8854** that belong to the same connection. If there are, SQLITE_LOCKED is 8855** returned. In this case there is no "blocking connection", so invoking 8856** sqlite3_unlock_notify() results in the unlock-notify callback being 8857** invoked immediately. If the application then re-attempts the "DROP TABLE" 8858** or "DROP INDEX" query, an infinite loop might be the result. 8859** 8860** One way around this problem is to check the extended error code returned 8861** by an sqlite3_step() call. ^(If there is a blocking connection, then the 8862** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 8863** the special "DROP TABLE/INDEX" case, the extended error code is just 8864** SQLITE_LOCKED.)^ 8865*/ 8866int sqlite3_unlock_notify( 8867 sqlite3 *pBlocked, /* Waiting connection */ 8868 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 8869 void *pNotifyArg /* Argument to pass to xNotify */ 8870); 8871 8872 8873/* 8874** CAPI3REF: String Comparison 8875** 8876** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 8877** and extensions to compare the contents of two buffers containing UTF-8 8878** strings in a case-independent fashion, using the same definition of "case 8879** independence" that SQLite uses internally when comparing identifiers. 8880*/ 8881int sqlite3_stricmp(const char *, const char *); 8882int sqlite3_strnicmp(const char *, const char *, int); 8883 8884/* 8885** CAPI3REF: String Globbing 8886* 8887** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 8888** string X matches the [GLOB] pattern P. 8889** ^The definition of [GLOB] pattern matching used in 8890** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 8891** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 8892** is case sensitive. 8893** 8894** Note that this routine returns zero on a match and non-zero if the strings 8895** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8896** 8897** See also: [sqlite3_strlike()]. 8898*/ 8899int sqlite3_strglob(const char *zGlob, const char *zStr); 8900 8901/* 8902** CAPI3REF: String LIKE Matching 8903* 8904** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 8905** string X matches the [LIKE] pattern P with escape character E. 8906** ^The definition of [LIKE] pattern matching used in 8907** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 8908** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 8909** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 8910** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 8911** insensitive - equivalent upper and lower case ASCII characters match 8912** one another. 8913** 8914** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 8915** only ASCII characters are case folded. 8916** 8917** Note that this routine returns zero on a match and non-zero if the strings 8918** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8919** 8920** See also: [sqlite3_strglob()]. 8921*/ 8922int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8923 8924/* 8925** CAPI3REF: Error Logging Interface 8926** 8927** ^The [sqlite3_log()] interface writes a message into the [error log] 8928** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8929** ^If logging is enabled, the zFormat string and subsequent arguments are 8930** used with [sqlite3_snprintf()] to generate the final output string. 8931** 8932** The sqlite3_log() interface is intended for use by extensions such as 8933** virtual tables, collating functions, and SQL functions. While there is 8934** nothing to prevent an application from calling sqlite3_log(), doing so 8935** is considered bad form. 8936** 8937** The zFormat string must not be NULL. 8938** 8939** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8940** will not use dynamically allocated memory. The log message is stored in 8941** a fixed-length buffer on the stack. If the log message is longer than 8942** a few hundred characters, it will be truncated to the length of the 8943** buffer. 8944*/ 8945void sqlite3_log(int iErrCode, const char *zFormat, ...); 8946 8947/* 8948** CAPI3REF: Write-Ahead Log Commit Hook 8949** METHOD: sqlite3 8950** 8951** ^The [sqlite3_wal_hook()] function is used to register a callback that 8952** is invoked each time data is committed to a database in wal mode. 8953** 8954** ^(The callback is invoked by SQLite after the commit has taken place and 8955** the associated write-lock on the database released)^, so the implementation 8956** may read, write or [checkpoint] the database as required. 8957** 8958** ^The first parameter passed to the callback function when it is invoked 8959** is a copy of the third parameter passed to sqlite3_wal_hook() when 8960** registering the callback. ^The second is a copy of the database handle. 8961** ^The third parameter is the name of the database that was written to - 8962** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8963** is the number of pages currently in the write-ahead log file, 8964** including those that were just committed. 8965** 8966** The callback function should normally return [SQLITE_OK]. ^If an error 8967** code is returned, that error will propagate back up through the 8968** SQLite code base to cause the statement that provoked the callback 8969** to report an error, though the commit will have still occurred. If the 8970** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8971** that does not correspond to any valid SQLite error code, the results 8972** are undefined. 8973** 8974** A single database handle may have at most a single write-ahead log callback 8975** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8976** previously registered write-ahead log callback. ^Note that the 8977** [sqlite3_wal_autocheckpoint()] interface and the 8978** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8979** overwrite any prior [sqlite3_wal_hook()] settings. 8980*/ 8981void *sqlite3_wal_hook( 8982 sqlite3*, 8983 int(*)(void *,sqlite3*,const char*,int), 8984 void* 8985); 8986 8987/* 8988** CAPI3REF: Configure an auto-checkpoint 8989** METHOD: sqlite3 8990** 8991** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8992** [sqlite3_wal_hook()] that causes any database on [database connection] D 8993** to automatically [checkpoint] 8994** after committing a transaction if there are N or 8995** more frames in the [write-ahead log] file. ^Passing zero or 8996** a negative value as the nFrame parameter disables automatic 8997** checkpoints entirely. 8998** 8999** ^The callback registered by this function replaces any existing callback 9000** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 9001** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 9002** configured by this function. 9003** 9004** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 9005** from SQL. 9006** 9007** ^Checkpoints initiated by this mechanism are 9008** [sqlite3_wal_checkpoint_v2|PASSIVE]. 9009** 9010** ^Every new [database connection] defaults to having the auto-checkpoint 9011** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 9012** pages. The use of this interface 9013** is only necessary if the default setting is found to be suboptimal 9014** for a particular application. 9015*/ 9016int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 9017 9018/* 9019** CAPI3REF: Checkpoint a database 9020** METHOD: sqlite3 9021** 9022** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 9023** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 9024** 9025** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 9026** [write-ahead log] for database X on [database connection] D to be 9027** transferred into the database file and for the write-ahead log to 9028** be reset. See the [checkpointing] documentation for addition 9029** information. 9030** 9031** This interface used to be the only way to cause a checkpoint to 9032** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 9033** interface was added. This interface is retained for backwards 9034** compatibility and as a convenience for applications that need to manually 9035** start a callback but which do not need the full power (and corresponding 9036** complication) of [sqlite3_wal_checkpoint_v2()]. 9037*/ 9038int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 9039 9040/* 9041** CAPI3REF: Checkpoint a database 9042** METHOD: sqlite3 9043** 9044** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 9045** operation on database X of [database connection] D in mode M. Status 9046** information is written back into integers pointed to by L and C.)^ 9047** ^(The M parameter must be a valid [checkpoint mode]:)^ 9048** 9049** <dl> 9050** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 9051** ^Checkpoint as many frames as possible without waiting for any database 9052** readers or writers to finish, then sync the database file if all frames 9053** in the log were checkpointed. ^The [busy-handler callback] 9054** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 9055** ^On the other hand, passive mode might leave the checkpoint unfinished 9056** if there are concurrent readers or writers. 9057** 9058** <dt>SQLITE_CHECKPOINT_FULL<dd> 9059** ^This mode blocks (it invokes the 9060** [sqlite3_busy_handler|busy-handler callback]) until there is no 9061** database writer and all readers are reading from the most recent database 9062** snapshot. ^It then checkpoints all frames in the log file and syncs the 9063** database file. ^This mode blocks new database writers while it is pending, 9064** but new database readers are allowed to continue unimpeded. 9065** 9066** <dt>SQLITE_CHECKPOINT_RESTART<dd> 9067** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 9068** that after checkpointing the log file it blocks (calls the 9069** [busy-handler callback]) 9070** until all readers are reading from the database file only. ^This ensures 9071** that the next writer will restart the log file from the beginning. 9072** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 9073** database writer attempts while it is pending, but does not impede readers. 9074** 9075** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 9076** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 9077** addition that it also truncates the log file to zero bytes just prior 9078** to a successful return. 9079** </dl> 9080** 9081** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 9082** the log file or to -1 if the checkpoint could not run because 9083** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 9084** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 9085** log file (including any that were already checkpointed before the function 9086** was called) or to -1 if the checkpoint could not run due to an error or 9087** because the database is not in WAL mode. ^Note that upon successful 9088** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 9089** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 9090** 9091** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 9092** any other process is running a checkpoint operation at the same time, the 9093** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 9094** busy-handler configured, it will not be invoked in this case. 9095** 9096** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 9097** exclusive "writer" lock on the database file. ^If the writer lock cannot be 9098** obtained immediately, and a busy-handler is configured, it is invoked and 9099** the writer lock retried until either the busy-handler returns 0 or the lock 9100** is successfully obtained. ^The busy-handler is also invoked while waiting for 9101** database readers as described above. ^If the busy-handler returns 0 before 9102** the writer lock is obtained or while waiting for database readers, the 9103** checkpoint operation proceeds from that point in the same way as 9104** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 9105** without blocking any further. ^SQLITE_BUSY is returned in this case. 9106** 9107** ^If parameter zDb is NULL or points to a zero length string, then the 9108** specified operation is attempted on all WAL databases [attached] to 9109** [database connection] db. In this case the 9110** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 9111** an SQLITE_BUSY error is encountered when processing one or more of the 9112** attached WAL databases, the operation is still attempted on any remaining 9113** attached databases and SQLITE_BUSY is returned at the end. ^If any other 9114** error occurs while processing an attached database, processing is abandoned 9115** and the error code is returned to the caller immediately. ^If no error 9116** (SQLITE_BUSY or otherwise) is encountered while processing the attached 9117** databases, SQLITE_OK is returned. 9118** 9119** ^If database zDb is the name of an attached database that is not in WAL 9120** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 9121** zDb is not NULL (or a zero length string) and is not the name of any 9122** attached database, SQLITE_ERROR is returned to the caller. 9123** 9124** ^Unless it returns SQLITE_MISUSE, 9125** the sqlite3_wal_checkpoint_v2() interface 9126** sets the error information that is queried by 9127** [sqlite3_errcode()] and [sqlite3_errmsg()]. 9128** 9129** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 9130** from SQL. 9131*/ 9132int sqlite3_wal_checkpoint_v2( 9133 sqlite3 *db, /* Database handle */ 9134 const char *zDb, /* Name of attached database (or NULL) */ 9135 int eMode, /* SQLITE_CHECKPOINT_* value */ 9136 int *pnLog, /* OUT: Size of WAL log in frames */ 9137 int *pnCkpt /* OUT: Total number of frames checkpointed */ 9138); 9139 9140/* 9141** CAPI3REF: Checkpoint Mode Values 9142** KEYWORDS: {checkpoint mode} 9143** 9144** These constants define all valid values for the "checkpoint mode" passed 9145** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 9146** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 9147** meaning of each of these checkpoint modes. 9148*/ 9149#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 9150#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 9151#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 9152#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 9153 9154/* 9155** CAPI3REF: Virtual Table Interface Configuration 9156** 9157** This function may be called by either the [xConnect] or [xCreate] method 9158** of a [virtual table] implementation to configure 9159** various facets of the virtual table interface. 9160** 9161** If this interface is invoked outside the context of an xConnect or 9162** xCreate virtual table method then the behavior is undefined. 9163** 9164** In the call sqlite3_vtab_config(D,C,...) the D parameter is the 9165** [database connection] in which the virtual table is being created and 9166** which is passed in as the first argument to the [xConnect] or [xCreate] 9167** method that is invoking sqlite3_vtab_config(). The C parameter is one 9168** of the [virtual table configuration options]. The presence and meaning 9169** of parameters after C depend on which [virtual table configuration option] 9170** is used. 9171*/ 9172int sqlite3_vtab_config(sqlite3*, int op, ...); 9173 9174/* 9175** CAPI3REF: Virtual Table Configuration Options 9176** KEYWORDS: {virtual table configuration options} 9177** KEYWORDS: {virtual table configuration option} 9178** 9179** These macros define the various options to the 9180** [sqlite3_vtab_config()] interface that [virtual table] implementations 9181** can use to customize and optimize their behavior. 9182** 9183** <dl> 9184** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]] 9185** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt> 9186** <dd>Calls of the form 9187** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 9188** where X is an integer. If X is zero, then the [virtual table] whose 9189** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 9190** support constraints. In this configuration (which is the default) if 9191** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 9192** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 9193** specified as part of the users SQL statement, regardless of the actual 9194** ON CONFLICT mode specified. 9195** 9196** If X is non-zero, then the virtual table implementation guarantees 9197** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 9198** any modifications to internal or persistent data structures have been made. 9199** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 9200** is able to roll back a statement or database transaction, and abandon 9201** or continue processing the current SQL statement as appropriate. 9202** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 9203** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 9204** had been ABORT. 9205** 9206** Virtual table implementations that are required to handle OR REPLACE 9207** must do so within the [xUpdate] method. If a call to the 9208** [sqlite3_vtab_on_conflict()] function indicates that the current ON 9209** CONFLICT policy is REPLACE, the virtual table implementation should 9210** silently replace the appropriate rows within the xUpdate callback and 9211** return SQLITE_OK. Or, if this is not possible, it may return 9212** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 9213** constraint handling. 9214** </dd> 9215** 9216** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt> 9217** <dd>Calls of the form 9218** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the 9219** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9220** prohibits that virtual table from being used from within triggers and 9221** views. 9222** </dd> 9223** 9224** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt> 9225** <dd>Calls of the form 9226** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the 9227** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9228** identify that virtual table as being safe to use from within triggers 9229** and views. Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the 9230** virtual table can do no serious harm even if it is controlled by a 9231** malicious hacker. Developers should avoid setting the SQLITE_VTAB_INNOCUOUS 9232** flag unless absolutely necessary. 9233** </dd> 9234** </dl> 9235*/ 9236#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 9237#define SQLITE_VTAB_INNOCUOUS 2 9238#define SQLITE_VTAB_DIRECTONLY 3 9239 9240/* 9241** CAPI3REF: Determine The Virtual Table Conflict Policy 9242** 9243** This function may only be called from within a call to the [xUpdate] method 9244** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 9245** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 9246** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 9247** of the SQL statement that triggered the call to the [xUpdate] method of the 9248** [virtual table]. 9249*/ 9250int sqlite3_vtab_on_conflict(sqlite3 *); 9251 9252/* 9253** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 9254** 9255** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 9256** method of a [virtual table], then it might return true if the 9257** column is being fetched as part of an UPDATE operation during which the 9258** column value will not change. The virtual table implementation can use 9259** this hint as permission to substitute a return value that is less 9260** expensive to compute and that the corresponding 9261** [xUpdate] method understands as a "no-change" value. 9262** 9263** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 9264** the column is not changed by the UPDATE statement, then the xColumn 9265** method can optionally return without setting a result, without calling 9266** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 9267** In that case, [sqlite3_value_nochange(X)] will return true for the 9268** same column in the [xUpdate] method. 9269** 9270** The sqlite3_vtab_nochange() routine is an optimization. Virtual table 9271** implementations should continue to give a correct answer even if the 9272** sqlite3_vtab_nochange() interface were to always return false. In the 9273** current implementation, the sqlite3_vtab_nochange() interface does always 9274** returns false for the enhanced [UPDATE FROM] statement. 9275*/ 9276int sqlite3_vtab_nochange(sqlite3_context*); 9277 9278/* 9279** CAPI3REF: Determine The Collation For a Virtual Table Constraint 9280** 9281** This function may only be called from within a call to the [xBestIndex] 9282** method of a [virtual table]. 9283** 9284** The first argument must be the sqlite3_index_info object that is the 9285** first parameter to the xBestIndex() method. The second argument must be 9286** an index into the aConstraint[] array belonging to the sqlite3_index_info 9287** structure passed to xBestIndex. This function returns a pointer to a buffer 9288** containing the name of the collation sequence for the corresponding 9289** constraint. 9290*/ 9291SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 9292 9293/* 9294** CAPI3REF: Conflict resolution modes 9295** KEYWORDS: {conflict resolution mode} 9296** 9297** These constants are returned by [sqlite3_vtab_on_conflict()] to 9298** inform a [virtual table] implementation what the [ON CONFLICT] mode 9299** is for the SQL statement being evaluated. 9300** 9301** Note that the [SQLITE_IGNORE] constant is also used as a potential 9302** return value from the [sqlite3_set_authorizer()] callback and that 9303** [SQLITE_ABORT] is also a [result code]. 9304*/ 9305#define SQLITE_ROLLBACK 1 9306/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 9307#define SQLITE_FAIL 3 9308/* #define SQLITE_ABORT 4 // Also an error code */ 9309#define SQLITE_REPLACE 5 9310 9311/* 9312** CAPI3REF: Prepared Statement Scan Status Opcodes 9313** KEYWORDS: {scanstatus options} 9314** 9315** The following constants can be used for the T parameter to the 9316** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 9317** different metric for sqlite3_stmt_scanstatus() to return. 9318** 9319** When the value returned to V is a string, space to hold that string is 9320** managed by the prepared statement S and will be automatically freed when 9321** S is finalized. 9322** 9323** <dl> 9324** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 9325** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be 9326** set to the total number of times that the X-th loop has run.</dd> 9327** 9328** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 9329** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set 9330** to the total number of rows examined by all iterations of the X-th loop.</dd> 9331** 9332** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 9333** <dd>^The "double" variable pointed to by the V parameter will be set to the 9334** query planner's estimate for the average number of rows output from each 9335** iteration of the X-th loop. If the query planner's estimates was accurate, 9336** then this value will approximate the quotient NVISIT/NLOOP and the 9337** product of this value for all prior loops with the same SELECTID will 9338** be the NLOOP value for the current loop. 9339** 9340** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 9341** <dd>^The "const char *" variable pointed to by the V parameter will be set 9342** to a zero-terminated UTF-8 string containing the name of the index or table 9343** used for the X-th loop. 9344** 9345** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 9346** <dd>^The "const char *" variable pointed to by the V parameter will be set 9347** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 9348** description for the X-th loop. 9349** 9350** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 9351** <dd>^The "int" variable pointed to by the V parameter will be set to the 9352** "select-id" for the X-th loop. The select-id identifies which query or 9353** subquery the loop is part of. The main query has a select-id of zero. 9354** The select-id is the same value as is output in the first column 9355** of an [EXPLAIN QUERY PLAN] query. 9356** </dl> 9357*/ 9358#define SQLITE_SCANSTAT_NLOOP 0 9359#define SQLITE_SCANSTAT_NVISIT 1 9360#define SQLITE_SCANSTAT_EST 2 9361#define SQLITE_SCANSTAT_NAME 3 9362#define SQLITE_SCANSTAT_EXPLAIN 4 9363#define SQLITE_SCANSTAT_SELECTID 5 9364 9365/* 9366** CAPI3REF: Prepared Statement Scan Status 9367** METHOD: sqlite3_stmt 9368** 9369** This interface returns information about the predicted and measured 9370** performance for pStmt. Advanced applications can use this 9371** interface to compare the predicted and the measured performance and 9372** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 9373** 9374** Since this interface is expected to be rarely used, it is only 9375** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 9376** compile-time option. 9377** 9378** The "iScanStatusOp" parameter determines which status information to return. 9379** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 9380** of this interface is undefined. 9381** ^The requested measurement is written into a variable pointed to by 9382** the "pOut" parameter. 9383** Parameter "idx" identifies the specific loop to retrieve statistics for. 9384** Loops are numbered starting from zero. ^If idx is out of range - less than 9385** zero or greater than or equal to the total number of loops used to implement 9386** the statement - a non-zero value is returned and the variable that pOut 9387** points to is unchanged. 9388** 9389** ^Statistics might not be available for all loops in all statements. ^In cases 9390** where there exist loops with no available statistics, this function behaves 9391** as if the loop did not exist - it returns non-zero and leave the variable 9392** that pOut points to unchanged. 9393** 9394** See also: [sqlite3_stmt_scanstatus_reset()] 9395*/ 9396int sqlite3_stmt_scanstatus( 9397 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 9398 int idx, /* Index of loop to report on */ 9399 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 9400 void *pOut /* Result written here */ 9401); 9402 9403/* 9404** CAPI3REF: Zero Scan-Status Counters 9405** METHOD: sqlite3_stmt 9406** 9407** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 9408** 9409** This API is only available if the library is built with pre-processor 9410** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 9411*/ 9412void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 9413 9414/* 9415** CAPI3REF: Flush caches to disk mid-transaction 9416** METHOD: sqlite3 9417** 9418** ^If a write-transaction is open on [database connection] D when the 9419** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 9420** pages in the pager-cache that are not currently in use are written out 9421** to disk. A dirty page may be in use if a database cursor created by an 9422** active SQL statement is reading from it, or if it is page 1 of a database 9423** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 9424** interface flushes caches for all schemas - "main", "temp", and 9425** any [attached] databases. 9426** 9427** ^If this function needs to obtain extra database locks before dirty pages 9428** can be flushed to disk, it does so. ^If those locks cannot be obtained 9429** immediately and there is a busy-handler callback configured, it is invoked 9430** in the usual manner. ^If the required lock still cannot be obtained, then 9431** the database is skipped and an attempt made to flush any dirty pages 9432** belonging to the next (if any) database. ^If any databases are skipped 9433** because locks cannot be obtained, but no other error occurs, this 9434** function returns SQLITE_BUSY. 9435** 9436** ^If any other error occurs while flushing dirty pages to disk (for 9437** example an IO error or out-of-memory condition), then processing is 9438** abandoned and an SQLite [error code] is returned to the caller immediately. 9439** 9440** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 9441** 9442** ^This function does not set the database handle error code or message 9443** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 9444*/ 9445int sqlite3_db_cacheflush(sqlite3*); 9446 9447/* 9448** CAPI3REF: The pre-update hook. 9449** METHOD: sqlite3 9450** 9451** ^These interfaces are only available if SQLite is compiled using the 9452** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 9453** 9454** ^The [sqlite3_preupdate_hook()] interface registers a callback function 9455** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 9456** on a database table. 9457** ^At most one preupdate hook may be registered at a time on a single 9458** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 9459** the previous setting. 9460** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 9461** with a NULL pointer as the second parameter. 9462** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 9463** the first parameter to callbacks. 9464** 9465** ^The preupdate hook only fires for changes to real database tables; the 9466** preupdate hook is not invoked for changes to [virtual tables] or to 9467** system tables like sqlite_sequence or sqlite_stat1. 9468** 9469** ^The second parameter to the preupdate callback is a pointer to 9470** the [database connection] that registered the preupdate hook. 9471** ^The third parameter to the preupdate callback is one of the constants 9472** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 9473** kind of update operation that is about to occur. 9474** ^(The fourth parameter to the preupdate callback is the name of the 9475** database within the database connection that is being modified. This 9476** will be "main" for the main database or "temp" for TEMP tables or 9477** the name given after the AS keyword in the [ATTACH] statement for attached 9478** databases.)^ 9479** ^The fifth parameter to the preupdate callback is the name of the 9480** table that is being modified. 9481** 9482** For an UPDATE or DELETE operation on a [rowid table], the sixth 9483** parameter passed to the preupdate callback is the initial [rowid] of the 9484** row being modified or deleted. For an INSERT operation on a rowid table, 9485** or any operation on a WITHOUT ROWID table, the value of the sixth 9486** parameter is undefined. For an INSERT or UPDATE on a rowid table the 9487** seventh parameter is the final rowid value of the row being inserted 9488** or updated. The value of the seventh parameter passed to the callback 9489** function is not defined for operations on WITHOUT ROWID tables, or for 9490** DELETE operations on rowid tables. 9491** 9492** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 9493** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 9494** provide additional information about a preupdate event. These routines 9495** may only be called from within a preupdate callback. Invoking any of 9496** these routines from outside of a preupdate callback or with a 9497** [database connection] pointer that is different from the one supplied 9498** to the preupdate callback results in undefined and probably undesirable 9499** behavior. 9500** 9501** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 9502** in the row that is being inserted, updated, or deleted. 9503** 9504** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 9505** a [protected sqlite3_value] that contains the value of the Nth column of 9506** the table row before it is updated. The N parameter must be between 0 9507** and one less than the number of columns or the behavior will be 9508** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 9509** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 9510** behavior is undefined. The [sqlite3_value] that P points to 9511** will be destroyed when the preupdate callback returns. 9512** 9513** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 9514** a [protected sqlite3_value] that contains the value of the Nth column of 9515** the table row after it is updated. The N parameter must be between 0 9516** and one less than the number of columns or the behavior will be 9517** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 9518** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 9519** behavior is undefined. The [sqlite3_value] that P points to 9520** will be destroyed when the preupdate callback returns. 9521** 9522** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 9523** callback was invoked as a result of a direct insert, update, or delete 9524** operation; or 1 for inserts, updates, or deletes invoked by top-level 9525** triggers; or 2 for changes resulting from triggers called by top-level 9526** triggers; and so forth. 9527** 9528** See also: [sqlite3_update_hook()] 9529*/ 9530#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 9531void *sqlite3_preupdate_hook( 9532 sqlite3 *db, 9533 void(*xPreUpdate)( 9534 void *pCtx, /* Copy of third arg to preupdate_hook() */ 9535 sqlite3 *db, /* Database handle */ 9536 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 9537 char const *zDb, /* Database name */ 9538 char const *zName, /* Table name */ 9539 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 9540 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 9541 ), 9542 void* 9543); 9544int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 9545int sqlite3_preupdate_count(sqlite3 *); 9546int sqlite3_preupdate_depth(sqlite3 *); 9547int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 9548#endif 9549 9550/* 9551** CAPI3REF: Low-level system error code 9552** METHOD: sqlite3 9553** 9554** ^Attempt to return the underlying operating system error code or error 9555** number that caused the most recent I/O error or failure to open a file. 9556** The return value is OS-dependent. For example, on unix systems, after 9557** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 9558** called to get back the underlying "errno" that caused the problem, such 9559** as ENOSPC, EAUTH, EISDIR, and so forth. 9560*/ 9561int sqlite3_system_errno(sqlite3*); 9562 9563/* 9564** CAPI3REF: Database Snapshot 9565** KEYWORDS: {snapshot} {sqlite3_snapshot} 9566** 9567** An instance of the snapshot object records the state of a [WAL mode] 9568** database for some specific point in history. 9569** 9570** In [WAL mode], multiple [database connections] that are open on the 9571** same database file can each be reading a different historical version 9572** of the database file. When a [database connection] begins a read 9573** transaction, that connection sees an unchanging copy of the database 9574** as it existed for the point in time when the transaction first started. 9575** Subsequent changes to the database from other connections are not seen 9576** by the reader until a new read transaction is started. 9577** 9578** The sqlite3_snapshot object records state information about an historical 9579** version of the database file so that it is possible to later open a new read 9580** transaction that sees that historical version of the database rather than 9581** the most recent version. 9582*/ 9583typedef struct sqlite3_snapshot { 9584 unsigned char hidden[48]; 9585} sqlite3_snapshot; 9586 9587/* 9588** CAPI3REF: Record A Database Snapshot 9589** CONSTRUCTOR: sqlite3_snapshot 9590** 9591** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 9592** new [sqlite3_snapshot] object that records the current state of 9593** schema S in database connection D. ^On success, the 9594** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 9595** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 9596** If there is not already a read-transaction open on schema S when 9597** this function is called, one is opened automatically. 9598** 9599** The following must be true for this function to succeed. If any of 9600** the following statements are false when sqlite3_snapshot_get() is 9601** called, SQLITE_ERROR is returned. The final value of *P is undefined 9602** in this case. 9603** 9604** <ul> 9605** <li> The database handle must not be in [autocommit mode]. 9606** 9607** <li> Schema S of [database connection] D must be a [WAL mode] database. 9608** 9609** <li> There must not be a write transaction open on schema S of database 9610** connection D. 9611** 9612** <li> One or more transactions must have been written to the current wal 9613** file since it was created on disk (by any connection). This means 9614** that a snapshot cannot be taken on a wal mode database with no wal 9615** file immediately after it is first opened. At least one transaction 9616** must be written to it first. 9617** </ul> 9618** 9619** This function may also return SQLITE_NOMEM. If it is called with the 9620** database handle in autocommit mode but fails for some other reason, 9621** whether or not a read transaction is opened on schema S is undefined. 9622** 9623** The [sqlite3_snapshot] object returned from a successful call to 9624** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 9625** to avoid a memory leak. 9626** 9627** The [sqlite3_snapshot_get()] interface is only available when the 9628** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9629*/ 9630SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 9631 sqlite3 *db, 9632 const char *zSchema, 9633 sqlite3_snapshot **ppSnapshot 9634); 9635 9636/* 9637** CAPI3REF: Start a read transaction on an historical snapshot 9638** METHOD: sqlite3_snapshot 9639** 9640** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read 9641** transaction or upgrades an existing one for schema S of 9642** [database connection] D such that the read transaction refers to 9643** historical [snapshot] P, rather than the most recent change to the 9644** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK 9645** on success or an appropriate [error code] if it fails. 9646** 9647** ^In order to succeed, the database connection must not be in 9648** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there 9649** is already a read transaction open on schema S, then the database handle 9650** must have no active statements (SELECT statements that have been passed 9651** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()). 9652** SQLITE_ERROR is returned if either of these conditions is violated, or 9653** if schema S does not exist, or if the snapshot object is invalid. 9654** 9655** ^A call to sqlite3_snapshot_open() will fail to open if the specified 9656** snapshot has been overwritten by a [checkpoint]. In this case 9657** SQLITE_ERROR_SNAPSHOT is returned. 9658** 9659** If there is already a read transaction open when this function is 9660** invoked, then the same read transaction remains open (on the same 9661** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT 9662** is returned. If another error code - for example SQLITE_PROTOCOL or an 9663** SQLITE_IOERR error code - is returned, then the final state of the 9664** read transaction is undefined. If SQLITE_OK is returned, then the 9665** read transaction is now open on database snapshot P. 9666** 9667** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 9668** database connection D does not know that the database file for 9669** schema S is in [WAL mode]. A database connection might not know 9670** that the database file is in [WAL mode] if there has been no prior 9671** I/O on that database connection, or if the database entered [WAL mode] 9672** after the most recent I/O on the database connection.)^ 9673** (Hint: Run "[PRAGMA application_id]" against a newly opened 9674** database connection in order to make it ready to use snapshots.) 9675** 9676** The [sqlite3_snapshot_open()] interface is only available when the 9677** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9678*/ 9679SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 9680 sqlite3 *db, 9681 const char *zSchema, 9682 sqlite3_snapshot *pSnapshot 9683); 9684 9685/* 9686** CAPI3REF: Destroy a snapshot 9687** DESTRUCTOR: sqlite3_snapshot 9688** 9689** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 9690** The application must eventually free every [sqlite3_snapshot] object 9691** using this routine to avoid a memory leak. 9692** 9693** The [sqlite3_snapshot_free()] interface is only available when the 9694** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9695*/ 9696SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 9697 9698/* 9699** CAPI3REF: Compare the ages of two snapshot handles. 9700** METHOD: sqlite3_snapshot 9701** 9702** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 9703** of two valid snapshot handles. 9704** 9705** If the two snapshot handles are not associated with the same database 9706** file, the result of the comparison is undefined. 9707** 9708** Additionally, the result of the comparison is only valid if both of the 9709** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 9710** last time the wal file was deleted. The wal file is deleted when the 9711** database is changed back to rollback mode or when the number of database 9712** clients drops to zero. If either snapshot handle was obtained before the 9713** wal file was last deleted, the value returned by this function 9714** is undefined. 9715** 9716** Otherwise, this API returns a negative value if P1 refers to an older 9717** snapshot than P2, zero if the two handles refer to the same database 9718** snapshot, and a positive value if P1 is a newer snapshot than P2. 9719** 9720** This interface is only available if SQLite is compiled with the 9721** [SQLITE_ENABLE_SNAPSHOT] option. 9722*/ 9723SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 9724 sqlite3_snapshot *p1, 9725 sqlite3_snapshot *p2 9726); 9727 9728/* 9729** CAPI3REF: Recover snapshots from a wal file 9730** METHOD: sqlite3_snapshot 9731** 9732** If a [WAL file] remains on disk after all database connections close 9733** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control] 9734** or because the last process to have the database opened exited without 9735** calling [sqlite3_close()]) and a new connection is subsequently opened 9736** on that database and [WAL file], the [sqlite3_snapshot_open()] interface 9737** will only be able to open the last transaction added to the WAL file 9738** even though the WAL file contains other valid transactions. 9739** 9740** This function attempts to scan the WAL file associated with database zDb 9741** of database handle db and make all valid snapshots available to 9742** sqlite3_snapshot_open(). It is an error if there is already a read 9743** transaction open on the database, or if the database is not a WAL mode 9744** database. 9745** 9746** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 9747** 9748** This interface is only available if SQLite is compiled with the 9749** [SQLITE_ENABLE_SNAPSHOT] option. 9750*/ 9751SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 9752 9753/* 9754** CAPI3REF: Serialize a database 9755** 9756** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 9757** that is a serialization of the S database on [database connection] D. 9758** If P is not a NULL pointer, then the size of the database in bytes 9759** is written into *P. 9760** 9761** For an ordinary on-disk database file, the serialization is just a 9762** copy of the disk file. For an in-memory database or a "TEMP" database, 9763** the serialization is the same sequence of bytes which would be written 9764** to disk if that database where backed up to disk. 9765** 9766** The usual case is that sqlite3_serialize() copies the serialization of 9767** the database into memory obtained from [sqlite3_malloc64()] and returns 9768** a pointer to that memory. The caller is responsible for freeing the 9769** returned value to avoid a memory leak. However, if the F argument 9770** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 9771** are made, and the sqlite3_serialize() function will return a pointer 9772** to the contiguous memory representation of the database that SQLite 9773** is currently using for that database, or NULL if the no such contiguous 9774** memory representation of the database exists. A contiguous memory 9775** representation of the database will usually only exist if there has 9776** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 9777** values of D and S. 9778** The size of the database is written into *P even if the 9779** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy 9780** of the database exists. 9781** 9782** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 9783** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 9784** allocation error occurs. 9785** 9786** This interface is only available if SQLite is compiled with the 9787** [SQLITE_ENABLE_DESERIALIZE] option. 9788*/ 9789unsigned char *sqlite3_serialize( 9790 sqlite3 *db, /* The database connection */ 9791 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 9792 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 9793 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 9794); 9795 9796/* 9797** CAPI3REF: Flags for sqlite3_serialize 9798** 9799** Zero or more of the following constants can be OR-ed together for 9800** the F argument to [sqlite3_serialize(D,S,P,F)]. 9801** 9802** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 9803** a pointer to contiguous in-memory database that it is currently using, 9804** without making a copy of the database. If SQLite is not currently using 9805** a contiguous in-memory database, then this option causes 9806** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 9807** using a contiguous in-memory database if it has been initialized by a 9808** prior call to [sqlite3_deserialize()]. 9809*/ 9810#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 9811 9812/* 9813** CAPI3REF: Deserialize a database 9814** 9815** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 9816** [database connection] D to disconnect from database S and then 9817** reopen S as an in-memory database based on the serialization contained 9818** in P. The serialized database P is N bytes in size. M is the size of 9819** the buffer P, which might be larger than N. If M is larger than N, and 9820** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 9821** permitted to add content to the in-memory database as long as the total 9822** size does not exceed M bytes. 9823** 9824** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 9825** invoke sqlite3_free() on the serialization buffer when the database 9826** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 9827** SQLite will try to increase the buffer size using sqlite3_realloc64() 9828** if writes on the database cause it to grow larger than M bytes. 9829** 9830** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 9831** database is currently in a read transaction or is involved in a backup 9832** operation. 9833** 9834** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 9835** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 9836** [sqlite3_free()] is invoked on argument P prior to returning. 9837** 9838** This interface is only available if SQLite is compiled with the 9839** [SQLITE_ENABLE_DESERIALIZE] option. 9840*/ 9841int sqlite3_deserialize( 9842 sqlite3 *db, /* The database connection */ 9843 const char *zSchema, /* Which DB to reopen with the deserialization */ 9844 unsigned char *pData, /* The serialized database content */ 9845 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 9846 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 9847 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 9848); 9849 9850/* 9851** CAPI3REF: Flags for sqlite3_deserialize() 9852** 9853** The following are allowed values for 6th argument (the F argument) to 9854** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 9855** 9856** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 9857** in the P argument is held in memory obtained from [sqlite3_malloc64()] 9858** and that SQLite should take ownership of this memory and automatically 9859** free it when it has finished using it. Without this flag, the caller 9860** is responsible for freeing any dynamically allocated memory. 9861** 9862** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 9863** grow the size of the database using calls to [sqlite3_realloc64()]. This 9864** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 9865** Without this flag, the deserialized database cannot increase in size beyond 9866** the number of bytes specified by the M parameter. 9867** 9868** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 9869** should be treated as read-only. 9870*/ 9871#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 9872#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 9873#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 9874 9875/* 9876** Undo the hack that converts floating point types to integer for 9877** builds on processors without floating point support. 9878*/ 9879#ifdef SQLITE_OMIT_FLOATING_POINT 9880# undef double 9881#endif 9882 9883#ifdef __cplusplus 9884} /* End of the 'extern "C"' block */ 9885#endif 9886#endif /* SQLITE3_H */ 9887