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. </dd> 2119** 2120** [[SQLITE_DBCONFIG_ENABLE_VIEW]] 2121** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt> 2122** <dd> ^This option is used to enable or disable [CREATE VIEW | views]. 2123** There should be two additional arguments. 2124** The first argument is an integer which is 0 to disable views, 2125** positive to enable views or negative to leave the setting unchanged. 2126** The second parameter is a pointer to an integer into which 2127** is written 0 or 1 to indicate whether views are disabled or enabled 2128** following this call. The second parameter may be a NULL pointer, in 2129** which case the view setting is not reported back. </dd> 2130** 2131** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]] 2132** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2133** <dd> ^This option is used to enable or disable the 2134** [fts3_tokenizer()] function which is part of the 2135** [FTS3] full-text search engine extension. 2136** There should be two additional arguments. 2137** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2138** positive to enable fts3_tokenizer() or negative to leave the setting 2139** unchanged. 2140** The second parameter is a pointer to an integer into which 2141** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2142** following this call. The second parameter may be a NULL pointer, in 2143** which case the new setting is not reported back. </dd> 2144** 2145** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]] 2146** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2147** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2148** interface independently of the [load_extension()] SQL function. 2149** The [sqlite3_enable_load_extension()] API enables or disables both the 2150** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2151** There should be two additional arguments. 2152** When the first argument to this interface is 1, then only the C-API is 2153** enabled and the SQL function remains disabled. If the first argument to 2154** this interface is 0, then both the C-API and the SQL function are disabled. 2155** If the first argument is -1, then no changes are made to state of either the 2156** C-API or the SQL function. 2157** The second parameter is a pointer to an integer into which 2158** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2159** is disabled or enabled following this call. The second parameter may 2160** be a NULL pointer, in which case the new setting is not reported back. 2161** </dd> 2162** 2163** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2164** <dd> ^This option is used to change the name of the "main" database 2165** schema. ^The sole argument is a pointer to a constant UTF8 string 2166** which will become the new schema name in place of "main". ^SQLite 2167** does not make a copy of the new main schema name string, so the application 2168** must ensure that the argument passed into this DBCONFIG option is unchanged 2169** until after the database connection closes. 2170** </dd> 2171** 2172** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]] 2173** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2174** <dd> Usually, when a database in wal mode is closed or detached from a 2175** database handle, SQLite checks if this will mean that there are now no 2176** connections at all to the database. If so, it performs a checkpoint 2177** operation before closing the connection. This option may be used to 2178** override this behaviour. The first parameter passed to this operation 2179** is an integer - positive to disable checkpoints-on-close, or zero (the 2180** default) to enable them, and negative to leave the setting unchanged. 2181** The second parameter is a pointer to an integer 2182** into which is written 0 or 1 to indicate whether checkpoints-on-close 2183** have been disabled - 0 if they are not disabled, 1 if they are. 2184** </dd> 2185** 2186** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2187** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2188** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2189** a single SQL query statement will always use the same algorithm regardless 2190** of values of [bound parameters].)^ The QPSG disables some query optimizations 2191** that look at the values of bound parameters, which can make some queries 2192** slower. But the QPSG has the advantage of more predictable behavior. With 2193** the QPSG active, SQLite will always use the same query plan in the field as 2194** was used during testing in the lab. 2195** The first argument to this setting is an integer which is 0 to disable 2196** the QPSG, positive to enable QPSG, or negative to leave the setting 2197** unchanged. The second parameter is a pointer to an integer into which 2198** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2199** following this call. 2200** </dd> 2201** 2202** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2203** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2204** include output for any operations performed by trigger programs. This 2205** option is used to set or clear (the default) a flag that governs this 2206** behavior. The first parameter passed to this operation is an integer - 2207** positive to enable output for trigger programs, or zero to disable it, 2208** or negative to leave the setting unchanged. 2209** The second parameter is a pointer to an integer into which is written 2210** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2211** it is not disabled, 1 if it is. 2212** </dd> 2213** 2214** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt> 2215** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run 2216** [VACUUM] in order to reset a database back to an empty database 2217** with no schema and no content. The following process works even for 2218** a badly corrupted database file: 2219** <ol> 2220** <li> If the database connection is newly opened, make sure it has read the 2221** database schema by preparing then discarding some query against the 2222** database, or calling sqlite3_table_column_metadata(), ignoring any 2223** errors. This step is only necessary if the application desires to keep 2224** the database in WAL mode after the reset if it was in WAL mode before 2225** the reset. 2226** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0); 2227** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0); 2228** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0); 2229** </ol> 2230** Because resetting a database is destructive and irreversible, the 2231** process requires the use of this obscure API and multiple steps to help 2232** ensure that it does not happen by accident. 2233** 2234** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt> 2235** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the 2236** "defensive" flag for a database connection. When the defensive 2237** flag is enabled, language features that allow ordinary SQL to 2238** deliberately corrupt the database file are disabled. The disabled 2239** features include but are not limited to the following: 2240** <ul> 2241** <li> The [PRAGMA writable_schema=ON] statement. 2242** <li> The [PRAGMA journal_mode=OFF] statement. 2243** <li> Writes to the [sqlite_dbpage] virtual table. 2244** <li> Direct writes to [shadow tables]. 2245** </ul> 2246** </dd> 2247** 2248** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt> 2249** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the 2250** "writable_schema" flag. This has the same effect and is logically equivalent 2251** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF]. 2252** The first argument to this setting is an integer which is 0 to disable 2253** the writable_schema, positive to enable writable_schema, or negative to 2254** leave the setting unchanged. The second parameter is a pointer to an 2255** integer into which is written 0 or 1 to indicate whether the writable_schema 2256** is enabled or disabled following this call. 2257** </dd> 2258** 2259** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]] 2260** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt> 2261** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates 2262** the legacy behavior of the [ALTER TABLE RENAME] command such it 2263** behaves as it did prior to [version 3.24.0] (2018-06-04). See the 2264** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for 2265** additional information. This feature can also be turned on and off 2266** using the [PRAGMA legacy_alter_table] statement. 2267** </dd> 2268** 2269** [[SQLITE_DBCONFIG_DQS_DML]] 2270** <dt>SQLITE_DBCONFIG_DQS_DML</td> 2271** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates 2272** the legacy [double-quoted string literal] misfeature for DML statements 2273** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The 2274** default value of this setting is determined by the [-DSQLITE_DQS] 2275** compile-time option. 2276** </dd> 2277** 2278** [[SQLITE_DBCONFIG_DQS_DDL]] 2279** <dt>SQLITE_DBCONFIG_DQS_DDL</td> 2280** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates 2281** the legacy [double-quoted string literal] misfeature for DDL statements, 2282** such as CREATE TABLE and CREATE INDEX. The 2283** default value of this setting is determined by the [-DSQLITE_DQS] 2284** compile-time option. 2285** </dd> 2286** 2287** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]] 2288** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td> 2289** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to 2290** assume that database schemas are untainted by malicious content. 2291** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite 2292** takes additional defensive steps to protect the application from harm 2293** including: 2294** <ul> 2295** <li> Prohibit the use of SQL functions inside triggers, views, 2296** CHECK constraints, DEFAULT clauses, expression indexes, 2297** partial indexes, or generated columns 2298** unless those functions are tagged with [SQLITE_INNOCUOUS]. 2299** <li> Prohibit the use of virtual tables inside of triggers or views 2300** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS]. 2301** </ul> 2302** This setting defaults to "on" for legacy compatibility, however 2303** all applications are advised to turn it off if possible. This setting 2304** can also be controlled using the [PRAGMA trusted_schema] statement. 2305** </dd> 2306** 2307** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]] 2308** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td> 2309** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates 2310** the legacy file format flag. When activated, this flag causes all newly 2311** created database file to have a schema format version number (the 4-byte 2312** integer found at offset 44 into the database header) of 1. This in turn 2313** means that the resulting database file will be readable and writable by 2314** any SQLite version back to 3.0.0 ([dateof:3.0.0]). Without this setting, 2315** newly created databases are generally not understandable by SQLite versions 2316** prior to 3.3.0 ([dateof:3.3.0]). As these words are written, there 2317** is now scarcely any need to generated database files that are compatible 2318** all the way back to version 3.0.0, and so this setting is of little 2319** practical use, but is provided so that SQLite can continue to claim the 2320** ability to generate new database files that are compatible with version 2321** 3.0.0. 2322** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on, 2323** the [VACUUM] command will fail with an obscure error when attempting to 2324** process a table with generated columns and a descending index. This is 2325** not considered a bug since SQLite versions 3.3.0 and earlier do not support 2326** either generated columns or decending indexes. 2327** </dd> 2328** </dl> 2329*/ 2330#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2331#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2332#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2333#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2334#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2335#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2336#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2337#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2338#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2339#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */ 2340#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */ 2341#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */ 2342#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */ 2343#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */ 2344#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */ 2345#define SQLITE_DBCONFIG_ENABLE_VIEW 1015 /* int int* */ 2346#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT 1016 /* int int* */ 2347#define SQLITE_DBCONFIG_TRUSTED_SCHEMA 1017 /* int int* */ 2348#define SQLITE_DBCONFIG_MAX 1017 /* Largest DBCONFIG */ 2349 2350/* 2351** CAPI3REF: Enable Or Disable Extended Result Codes 2352** METHOD: sqlite3 2353** 2354** ^The sqlite3_extended_result_codes() routine enables or disables the 2355** [extended result codes] feature of SQLite. ^The extended result 2356** codes are disabled by default for historical compatibility. 2357*/ 2358int sqlite3_extended_result_codes(sqlite3*, int onoff); 2359 2360/* 2361** CAPI3REF: Last Insert Rowid 2362** METHOD: sqlite3 2363** 2364** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2365** has a unique 64-bit signed 2366** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2367** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2368** names are not also used by explicitly declared columns. ^If 2369** the table has a column of type [INTEGER PRIMARY KEY] then that column 2370** is another alias for the rowid. 2371** 2372** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2373** the most recent successful [INSERT] into a rowid table or [virtual table] 2374** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2375** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2376** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2377** zero. 2378** 2379** As well as being set automatically as rows are inserted into database 2380** tables, the value returned by this function may be set explicitly by 2381** [sqlite3_set_last_insert_rowid()] 2382** 2383** Some virtual table implementations may INSERT rows into rowid tables as 2384** part of committing a transaction (e.g. to flush data accumulated in memory 2385** to disk). In this case subsequent calls to this function return the rowid 2386** associated with these internal INSERT operations, which leads to 2387** unintuitive results. Virtual table implementations that do write to rowid 2388** tables in this way can avoid this problem by restoring the original 2389** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2390** control to the user. 2391** 2392** ^(If an [INSERT] occurs within a trigger then this routine will 2393** return the [rowid] of the inserted row as long as the trigger is 2394** running. Once the trigger program ends, the value returned 2395** by this routine reverts to what it was before the trigger was fired.)^ 2396** 2397** ^An [INSERT] that fails due to a constraint violation is not a 2398** successful [INSERT] and does not change the value returned by this 2399** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2400** and INSERT OR ABORT make no changes to the return value of this 2401** routine when their insertion fails. ^(When INSERT OR REPLACE 2402** encounters a constraint violation, it does not fail. The 2403** INSERT continues to completion after deleting rows that caused 2404** the constraint problem so INSERT OR REPLACE will always change 2405** the return value of this interface.)^ 2406** 2407** ^For the purposes of this routine, an [INSERT] is considered to 2408** be successful even if it is subsequently rolled back. 2409** 2410** This function is accessible to SQL statements via the 2411** [last_insert_rowid() SQL function]. 2412** 2413** If a separate thread performs a new [INSERT] on the same 2414** database connection while the [sqlite3_last_insert_rowid()] 2415** function is running and thus changes the last insert [rowid], 2416** then the value returned by [sqlite3_last_insert_rowid()] is 2417** unpredictable and might not equal either the old or the new 2418** last insert [rowid]. 2419*/ 2420sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2421 2422/* 2423** CAPI3REF: Set the Last Insert Rowid value. 2424** METHOD: sqlite3 2425** 2426** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2427** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2428** without inserting a row into the database. 2429*/ 2430void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2431 2432/* 2433** CAPI3REF: Count The Number Of Rows Modified 2434** METHOD: sqlite3 2435** 2436** ^This function returns the number of rows modified, inserted or 2437** deleted by the most recently completed INSERT, UPDATE or DELETE 2438** statement on the database connection specified by the only parameter. 2439** ^Executing any other type of SQL statement does not modify the value 2440** returned by this function. 2441** 2442** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2443** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2444** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2445** 2446** Changes to a view that are intercepted by 2447** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2448** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2449** DELETE statement run on a view is always zero. Only changes made to real 2450** tables are counted. 2451** 2452** Things are more complicated if the sqlite3_changes() function is 2453** executed while a trigger program is running. This may happen if the 2454** program uses the [changes() SQL function], or if some other callback 2455** function invokes sqlite3_changes() directly. Essentially: 2456** 2457** <ul> 2458** <li> ^(Before entering a trigger program the value returned by 2459** sqlite3_changes() function is saved. After the trigger program 2460** has finished, the original value is restored.)^ 2461** 2462** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2463** statement sets the value returned by sqlite3_changes() 2464** upon completion as normal. Of course, this value will not include 2465** any changes performed by sub-triggers, as the sqlite3_changes() 2466** value will be saved and restored after each sub-trigger has run.)^ 2467** </ul> 2468** 2469** ^This means that if the changes() SQL function (or similar) is used 2470** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2471** returns the value as set when the calling statement began executing. 2472** ^If it is used by the second or subsequent such statement within a trigger 2473** program, the value returned reflects the number of rows modified by the 2474** previous INSERT, UPDATE or DELETE statement within the same trigger. 2475** 2476** If a separate thread makes changes on the same database connection 2477** while [sqlite3_changes()] is running then the value returned 2478** is unpredictable and not meaningful. 2479** 2480** See also: 2481** <ul> 2482** <li> the [sqlite3_total_changes()] interface 2483** <li> the [count_changes pragma] 2484** <li> the [changes() SQL function] 2485** <li> the [data_version pragma] 2486** </ul> 2487*/ 2488int sqlite3_changes(sqlite3*); 2489 2490/* 2491** CAPI3REF: Total Number Of Rows Modified 2492** METHOD: sqlite3 2493** 2494** ^This function returns the total number of rows inserted, modified or 2495** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2496** since the database connection was opened, including those executed as 2497** part of trigger programs. ^Executing any other type of SQL statement 2498** does not affect the value returned by sqlite3_total_changes(). 2499** 2500** ^Changes made as part of [foreign key actions] are included in the 2501** count, but those made as part of REPLACE constraint resolution are 2502** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2503** are not counted. 2504** 2505** The [sqlite3_total_changes(D)] interface only reports the number 2506** of rows that changed due to SQL statement run against database 2507** connection D. Any changes by other database connections are ignored. 2508** To detect changes against a database file from other database 2509** connections use the [PRAGMA data_version] command or the 2510** [SQLITE_FCNTL_DATA_VERSION] [file control]. 2511** 2512** If a separate thread makes changes on the same database connection 2513** while [sqlite3_total_changes()] is running then the value 2514** returned is unpredictable and not meaningful. 2515** 2516** See also: 2517** <ul> 2518** <li> the [sqlite3_changes()] interface 2519** <li> the [count_changes pragma] 2520** <li> the [changes() SQL function] 2521** <li> the [data_version pragma] 2522** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control] 2523** </ul> 2524*/ 2525int sqlite3_total_changes(sqlite3*); 2526 2527/* 2528** CAPI3REF: Interrupt A Long-Running Query 2529** METHOD: sqlite3 2530** 2531** ^This function causes any pending database operation to abort and 2532** return at its earliest opportunity. This routine is typically 2533** called in response to a user action such as pressing "Cancel" 2534** or Ctrl-C where the user wants a long query operation to halt 2535** immediately. 2536** 2537** ^It is safe to call this routine from a thread different from the 2538** thread that is currently running the database operation. But it 2539** is not safe to call this routine with a [database connection] that 2540** is closed or might close before sqlite3_interrupt() returns. 2541** 2542** ^If an SQL operation is very nearly finished at the time when 2543** sqlite3_interrupt() is called, then it might not have an opportunity 2544** to be interrupted and might continue to completion. 2545** 2546** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2547** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2548** that is inside an explicit transaction, then the entire transaction 2549** will be rolled back automatically. 2550** 2551** ^The sqlite3_interrupt(D) call is in effect until all currently running 2552** SQL statements on [database connection] D complete. ^Any new SQL statements 2553** that are started after the sqlite3_interrupt() call and before the 2554** running statement count reaches zero are interrupted as if they had been 2555** running prior to the sqlite3_interrupt() call. ^New SQL statements 2556** that are started after the running statement count reaches zero are 2557** not effected by the sqlite3_interrupt(). 2558** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2559** SQL statements is a no-op and has no effect on SQL statements 2560** that are started after the sqlite3_interrupt() call returns. 2561*/ 2562void sqlite3_interrupt(sqlite3*); 2563 2564/* 2565** CAPI3REF: Determine If An SQL Statement Is Complete 2566** 2567** These routines are useful during command-line input to determine if the 2568** currently entered text seems to form a complete SQL statement or 2569** if additional input is needed before sending the text into 2570** SQLite for parsing. ^These routines return 1 if the input string 2571** appears to be a complete SQL statement. ^A statement is judged to be 2572** complete if it ends with a semicolon token and is not a prefix of a 2573** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2574** string literals or quoted identifier names or comments are not 2575** independent tokens (they are part of the token in which they are 2576** embedded) and thus do not count as a statement terminator. ^Whitespace 2577** and comments that follow the final semicolon are ignored. 2578** 2579** ^These routines return 0 if the statement is incomplete. ^If a 2580** memory allocation fails, then SQLITE_NOMEM is returned. 2581** 2582** ^These routines do not parse the SQL statements thus 2583** will not detect syntactically incorrect SQL. 2584** 2585** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2586** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2587** automatically by sqlite3_complete16(). If that initialization fails, 2588** then the return value from sqlite3_complete16() will be non-zero 2589** regardless of whether or not the input SQL is complete.)^ 2590** 2591** The input to [sqlite3_complete()] must be a zero-terminated 2592** UTF-8 string. 2593** 2594** The input to [sqlite3_complete16()] must be a zero-terminated 2595** UTF-16 string in native byte order. 2596*/ 2597int sqlite3_complete(const char *sql); 2598int sqlite3_complete16(const void *sql); 2599 2600/* 2601** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2602** KEYWORDS: {busy-handler callback} {busy handler} 2603** METHOD: sqlite3 2604** 2605** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2606** that might be invoked with argument P whenever 2607** an attempt is made to access a database table associated with 2608** [database connection] D when another thread 2609** or process has the table locked. 2610** The sqlite3_busy_handler() interface is used to implement 2611** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2612** 2613** ^If the busy callback is NULL, then [SQLITE_BUSY] 2614** is returned immediately upon encountering the lock. ^If the busy callback 2615** is not NULL, then the callback might be invoked with two arguments. 2616** 2617** ^The first argument to the busy handler is a copy of the void* pointer which 2618** is the third argument to sqlite3_busy_handler(). ^The second argument to 2619** the busy handler callback is the number of times that the busy handler has 2620** been invoked previously for the same locking event. ^If the 2621** busy callback returns 0, then no additional attempts are made to 2622** access the database and [SQLITE_BUSY] is returned 2623** to the application. 2624** ^If the callback returns non-zero, then another attempt 2625** is made to access the database and the cycle repeats. 2626** 2627** The presence of a busy handler does not guarantee that it will be invoked 2628** when there is lock contention. ^If SQLite determines that invoking the busy 2629** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2630** to the application instead of invoking the 2631** busy handler. 2632** Consider a scenario where one process is holding a read lock that 2633** it is trying to promote to a reserved lock and 2634** a second process is holding a reserved lock that it is trying 2635** to promote to an exclusive lock. The first process cannot proceed 2636** because it is blocked by the second and the second process cannot 2637** proceed because it is blocked by the first. If both processes 2638** invoke the busy handlers, neither will make any progress. Therefore, 2639** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2640** will induce the first process to release its read lock and allow 2641** the second process to proceed. 2642** 2643** ^The default busy callback is NULL. 2644** 2645** ^(There can only be a single busy handler defined for each 2646** [database connection]. Setting a new busy handler clears any 2647** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2648** or evaluating [PRAGMA busy_timeout=N] will change the 2649** busy handler and thus clear any previously set busy handler. 2650** 2651** The busy callback should not take any actions which modify the 2652** database connection that invoked the busy handler. In other words, 2653** the busy handler is not reentrant. Any such actions 2654** result in undefined behavior. 2655** 2656** A busy handler must not close the database connection 2657** or [prepared statement] that invoked the busy handler. 2658*/ 2659int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2660 2661/* 2662** CAPI3REF: Set A Busy Timeout 2663** METHOD: sqlite3 2664** 2665** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2666** for a specified amount of time when a table is locked. ^The handler 2667** will sleep multiple times until at least "ms" milliseconds of sleeping 2668** have accumulated. ^After at least "ms" milliseconds of sleeping, 2669** the handler returns 0 which causes [sqlite3_step()] to return 2670** [SQLITE_BUSY]. 2671** 2672** ^Calling this routine with an argument less than or equal to zero 2673** turns off all busy handlers. 2674** 2675** ^(There can only be a single busy handler for a particular 2676** [database connection] at any given moment. If another busy handler 2677** was defined (using [sqlite3_busy_handler()]) prior to calling 2678** this routine, that other busy handler is cleared.)^ 2679** 2680** See also: [PRAGMA busy_timeout] 2681*/ 2682int sqlite3_busy_timeout(sqlite3*, int ms); 2683 2684/* 2685** CAPI3REF: Convenience Routines For Running Queries 2686** METHOD: sqlite3 2687** 2688** This is a legacy interface that is preserved for backwards compatibility. 2689** Use of this interface is not recommended. 2690** 2691** Definition: A <b>result table</b> is memory data structure created by the 2692** [sqlite3_get_table()] interface. A result table records the 2693** complete query results from one or more queries. 2694** 2695** The table conceptually has a number of rows and columns. But 2696** these numbers are not part of the result table itself. These 2697** numbers are obtained separately. Let N be the number of rows 2698** and M be the number of columns. 2699** 2700** A result table is an array of pointers to zero-terminated UTF-8 strings. 2701** There are (N+1)*M elements in the array. The first M pointers point 2702** to zero-terminated strings that contain the names of the columns. 2703** The remaining entries all point to query results. NULL values result 2704** in NULL pointers. All other values are in their UTF-8 zero-terminated 2705** string representation as returned by [sqlite3_column_text()]. 2706** 2707** A result table might consist of one or more memory allocations. 2708** It is not safe to pass a result table directly to [sqlite3_free()]. 2709** A result table should be deallocated using [sqlite3_free_table()]. 2710** 2711** ^(As an example of the result table format, suppose a query result 2712** is as follows: 2713** 2714** <blockquote><pre> 2715** Name | Age 2716** ----------------------- 2717** Alice | 43 2718** Bob | 28 2719** Cindy | 21 2720** </pre></blockquote> 2721** 2722** There are two columns (M==2) and three rows (N==3). Thus the 2723** result table has 8 entries. Suppose the result table is stored 2724** in an array named azResult. Then azResult holds this content: 2725** 2726** <blockquote><pre> 2727** azResult[0] = "Name"; 2728** azResult[1] = "Age"; 2729** azResult[2] = "Alice"; 2730** azResult[3] = "43"; 2731** azResult[4] = "Bob"; 2732** azResult[5] = "28"; 2733** azResult[6] = "Cindy"; 2734** azResult[7] = "21"; 2735** </pre></blockquote>)^ 2736** 2737** ^The sqlite3_get_table() function evaluates one or more 2738** semicolon-separated SQL statements in the zero-terminated UTF-8 2739** string of its 2nd parameter and returns a result table to the 2740** pointer given in its 3rd parameter. 2741** 2742** After the application has finished with the result from sqlite3_get_table(), 2743** it must pass the result table pointer to sqlite3_free_table() in order to 2744** release the memory that was malloced. Because of the way the 2745** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2746** function must not try to call [sqlite3_free()] directly. Only 2747** [sqlite3_free_table()] is able to release the memory properly and safely. 2748** 2749** The sqlite3_get_table() interface is implemented as a wrapper around 2750** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2751** to any internal data structures of SQLite. It uses only the public 2752** interface defined here. As a consequence, errors that occur in the 2753** wrapper layer outside of the internal [sqlite3_exec()] call are not 2754** reflected in subsequent calls to [sqlite3_errcode()] or 2755** [sqlite3_errmsg()]. 2756*/ 2757int sqlite3_get_table( 2758 sqlite3 *db, /* An open database */ 2759 const char *zSql, /* SQL to be evaluated */ 2760 char ***pazResult, /* Results of the query */ 2761 int *pnRow, /* Number of result rows written here */ 2762 int *pnColumn, /* Number of result columns written here */ 2763 char **pzErrmsg /* Error msg written here */ 2764); 2765void sqlite3_free_table(char **result); 2766 2767/* 2768** CAPI3REF: Formatted String Printing Functions 2769** 2770** These routines are work-alikes of the "printf()" family of functions 2771** from the standard C library. 2772** These routines understand most of the common formatting options from 2773** the standard library printf() 2774** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2775** See the [built-in printf()] documentation for details. 2776** 2777** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2778** results into memory obtained from [sqlite3_malloc64()]. 2779** The strings returned by these two routines should be 2780** released by [sqlite3_free()]. ^Both routines return a 2781** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2782** memory to hold the resulting string. 2783** 2784** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2785** the standard C library. The result is written into the 2786** buffer supplied as the second parameter whose size is given by 2787** the first parameter. Note that the order of the 2788** first two parameters is reversed from snprintf().)^ This is an 2789** historical accident that cannot be fixed without breaking 2790** backwards compatibility. ^(Note also that sqlite3_snprintf() 2791** returns a pointer to its buffer instead of the number of 2792** characters actually written into the buffer.)^ We admit that 2793** the number of characters written would be a more useful return 2794** value but we cannot change the implementation of sqlite3_snprintf() 2795** now without breaking compatibility. 2796** 2797** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2798** guarantees that the buffer is always zero-terminated. ^The first 2799** parameter "n" is the total size of the buffer, including space for 2800** the zero terminator. So the longest string that can be completely 2801** written will be n-1 characters. 2802** 2803** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2804** 2805** See also: [built-in printf()], [printf() SQL function] 2806*/ 2807char *sqlite3_mprintf(const char*,...); 2808char *sqlite3_vmprintf(const char*, va_list); 2809char *sqlite3_snprintf(int,char*,const char*, ...); 2810char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2811 2812/* 2813** CAPI3REF: Memory Allocation Subsystem 2814** 2815** The SQLite core uses these three routines for all of its own 2816** internal memory allocation needs. "Core" in the previous sentence 2817** does not include operating-system specific [VFS] implementation. The 2818** Windows VFS uses native malloc() and free() for some operations. 2819** 2820** ^The sqlite3_malloc() routine returns a pointer to a block 2821** of memory at least N bytes in length, where N is the parameter. 2822** ^If sqlite3_malloc() is unable to obtain sufficient free 2823** memory, it returns a NULL pointer. ^If the parameter N to 2824** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2825** a NULL pointer. 2826** 2827** ^The sqlite3_malloc64(N) routine works just like 2828** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2829** of a signed 32-bit integer. 2830** 2831** ^Calling sqlite3_free() with a pointer previously returned 2832** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2833** that it might be reused. ^The sqlite3_free() routine is 2834** a no-op if is called with a NULL pointer. Passing a NULL pointer 2835** to sqlite3_free() is harmless. After being freed, memory 2836** should neither be read nor written. Even reading previously freed 2837** memory might result in a segmentation fault or other severe error. 2838** Memory corruption, a segmentation fault, or other severe error 2839** might result if sqlite3_free() is called with a non-NULL pointer that 2840** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2841** 2842** ^The sqlite3_realloc(X,N) interface attempts to resize a 2843** prior memory allocation X to be at least N bytes. 2844** ^If the X parameter to sqlite3_realloc(X,N) 2845** is a NULL pointer then its behavior is identical to calling 2846** sqlite3_malloc(N). 2847** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2848** negative then the behavior is exactly the same as calling 2849** sqlite3_free(X). 2850** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2851** of at least N bytes in size or NULL if insufficient memory is available. 2852** ^If M is the size of the prior allocation, then min(N,M) bytes 2853** of the prior allocation are copied into the beginning of buffer returned 2854** by sqlite3_realloc(X,N) and the prior allocation is freed. 2855** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2856** prior allocation is not freed. 2857** 2858** ^The sqlite3_realloc64(X,N) interfaces works the same as 2859** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2860** of a 32-bit signed integer. 2861** 2862** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2863** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2864** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2865** ^The value returned by sqlite3_msize(X) might be larger than the number 2866** of bytes requested when X was allocated. ^If X is a NULL pointer then 2867** sqlite3_msize(X) returns zero. If X points to something that is not 2868** the beginning of memory allocation, or if it points to a formerly 2869** valid memory allocation that has now been freed, then the behavior 2870** of sqlite3_msize(X) is undefined and possibly harmful. 2871** 2872** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2873** sqlite3_malloc64(), and sqlite3_realloc64() 2874** is always aligned to at least an 8 byte boundary, or to a 2875** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2876** option is used. 2877** 2878** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2879** must be either NULL or else pointers obtained from a prior 2880** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2881** not yet been released. 2882** 2883** The application must not read or write any part of 2884** a block of memory after it has been released using 2885** [sqlite3_free()] or [sqlite3_realloc()]. 2886*/ 2887void *sqlite3_malloc(int); 2888void *sqlite3_malloc64(sqlite3_uint64); 2889void *sqlite3_realloc(void*, int); 2890void *sqlite3_realloc64(void*, sqlite3_uint64); 2891void sqlite3_free(void*); 2892sqlite3_uint64 sqlite3_msize(void*); 2893 2894/* 2895** CAPI3REF: Memory Allocator Statistics 2896** 2897** SQLite provides these two interfaces for reporting on the status 2898** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2899** routines, which form the built-in memory allocation subsystem. 2900** 2901** ^The [sqlite3_memory_used()] routine returns the number of bytes 2902** of memory currently outstanding (malloced but not freed). 2903** ^The [sqlite3_memory_highwater()] routine returns the maximum 2904** value of [sqlite3_memory_used()] since the high-water mark 2905** was last reset. ^The values returned by [sqlite3_memory_used()] and 2906** [sqlite3_memory_highwater()] include any overhead 2907** added by SQLite in its implementation of [sqlite3_malloc()], 2908** but not overhead added by the any underlying system library 2909** routines that [sqlite3_malloc()] may call. 2910** 2911** ^The memory high-water mark is reset to the current value of 2912** [sqlite3_memory_used()] if and only if the parameter to 2913** [sqlite3_memory_highwater()] is true. ^The value returned 2914** by [sqlite3_memory_highwater(1)] is the high-water mark 2915** prior to the reset. 2916*/ 2917sqlite3_int64 sqlite3_memory_used(void); 2918sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2919 2920/* 2921** CAPI3REF: Pseudo-Random Number Generator 2922** 2923** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2924** select random [ROWID | ROWIDs] when inserting new records into a table that 2925** already uses the largest possible [ROWID]. The PRNG is also used for 2926** the built-in random() and randomblob() SQL functions. This interface allows 2927** applications to access the same PRNG for other purposes. 2928** 2929** ^A call to this routine stores N bytes of randomness into buffer P. 2930** ^The P parameter can be a NULL pointer. 2931** 2932** ^If this routine has not been previously called or if the previous 2933** call had N less than one or a NULL pointer for P, then the PRNG is 2934** seeded using randomness obtained from the xRandomness method of 2935** the default [sqlite3_vfs] object. 2936** ^If the previous call to this routine had an N of 1 or more and a 2937** non-NULL P then the pseudo-randomness is generated 2938** internally and without recourse to the [sqlite3_vfs] xRandomness 2939** method. 2940*/ 2941void sqlite3_randomness(int N, void *P); 2942 2943/* 2944** CAPI3REF: Compile-Time Authorization Callbacks 2945** METHOD: sqlite3 2946** KEYWORDS: {authorizer callback} 2947** 2948** ^This routine registers an authorizer callback with a particular 2949** [database connection], supplied in the first argument. 2950** ^The authorizer callback is invoked as SQL statements are being compiled 2951** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2952** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2953** and [sqlite3_prepare16_v3()]. ^At various 2954** points during the compilation process, as logic is being created 2955** to perform various actions, the authorizer callback is invoked to 2956** see if those actions are allowed. ^The authorizer callback should 2957** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2958** specific action but allow the SQL statement to continue to be 2959** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2960** rejected with an error. ^If the authorizer callback returns 2961** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2962** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2963** the authorizer will fail with an error message. 2964** 2965** When the callback returns [SQLITE_OK], that means the operation 2966** requested is ok. ^When the callback returns [SQLITE_DENY], the 2967** [sqlite3_prepare_v2()] or equivalent call that triggered the 2968** authorizer will fail with an error message explaining that 2969** access is denied. 2970** 2971** ^The first parameter to the authorizer callback is a copy of the third 2972** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2973** to the callback is an integer [SQLITE_COPY | action code] that specifies 2974** the particular action to be authorized. ^The third through sixth parameters 2975** to the callback are either NULL pointers or zero-terminated strings 2976** that contain additional details about the action to be authorized. 2977** Applications must always be prepared to encounter a NULL pointer in any 2978** of the third through the sixth parameters of the authorization callback. 2979** 2980** ^If the action code is [SQLITE_READ] 2981** and the callback returns [SQLITE_IGNORE] then the 2982** [prepared statement] statement is constructed to substitute 2983** a NULL value in place of the table column that would have 2984** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2985** return can be used to deny an untrusted user access to individual 2986** columns of a table. 2987** ^When a table is referenced by a [SELECT] but no column values are 2988** extracted from that table (for example in a query like 2989** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2990** is invoked once for that table with a column name that is an empty string. 2991** ^If the action code is [SQLITE_DELETE] and the callback returns 2992** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2993** [truncate optimization] is disabled and all rows are deleted individually. 2994** 2995** An authorizer is used when [sqlite3_prepare | preparing] 2996** SQL statements from an untrusted source, to ensure that the SQL statements 2997** do not try to access data they are not allowed to see, or that they do not 2998** try to execute malicious statements that damage the database. For 2999** example, an application may allow a user to enter arbitrary 3000** SQL queries for evaluation by a database. But the application does 3001** not want the user to be able to make arbitrary changes to the 3002** database. An authorizer could then be put in place while the 3003** user-entered SQL is being [sqlite3_prepare | prepared] that 3004** disallows everything except [SELECT] statements. 3005** 3006** Applications that need to process SQL from untrusted sources 3007** might also consider lowering resource limits using [sqlite3_limit()] 3008** and limiting database size using the [max_page_count] [PRAGMA] 3009** in addition to using an authorizer. 3010** 3011** ^(Only a single authorizer can be in place on a database connection 3012** at a time. Each call to sqlite3_set_authorizer overrides the 3013** previous call.)^ ^Disable the authorizer by installing a NULL callback. 3014** The authorizer is disabled by default. 3015** 3016** The authorizer callback must not do anything that will modify 3017** the database connection that invoked the authorizer callback. 3018** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3019** database connections for the meaning of "modify" in this paragraph. 3020** 3021** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 3022** statement might be re-prepared during [sqlite3_step()] due to a 3023** schema change. Hence, the application should ensure that the 3024** correct authorizer callback remains in place during the [sqlite3_step()]. 3025** 3026** ^Note that the authorizer callback is invoked only during 3027** [sqlite3_prepare()] or its variants. Authorization is not 3028** performed during statement evaluation in [sqlite3_step()], unless 3029** as stated in the previous paragraph, sqlite3_step() invokes 3030** sqlite3_prepare_v2() to reprepare a statement after a schema change. 3031*/ 3032int sqlite3_set_authorizer( 3033 sqlite3*, 3034 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 3035 void *pUserData 3036); 3037 3038/* 3039** CAPI3REF: Authorizer Return Codes 3040** 3041** The [sqlite3_set_authorizer | authorizer callback function] must 3042** return either [SQLITE_OK] or one of these two constants in order 3043** to signal SQLite whether or not the action is permitted. See the 3044** [sqlite3_set_authorizer | authorizer documentation] for additional 3045** information. 3046** 3047** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 3048** returned from the [sqlite3_vtab_on_conflict()] interface. 3049*/ 3050#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 3051#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 3052 3053/* 3054** CAPI3REF: Authorizer Action Codes 3055** 3056** The [sqlite3_set_authorizer()] interface registers a callback function 3057** that is invoked to authorize certain SQL statement actions. The 3058** second parameter to the callback is an integer code that specifies 3059** what action is being authorized. These are the integer action codes that 3060** the authorizer callback may be passed. 3061** 3062** These action code values signify what kind of operation is to be 3063** authorized. The 3rd and 4th parameters to the authorization 3064** callback function will be parameters or NULL depending on which of these 3065** codes is used as the second parameter. ^(The 5th parameter to the 3066** authorizer callback is the name of the database ("main", "temp", 3067** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 3068** is the name of the inner-most trigger or view that is responsible for 3069** the access attempt or NULL if this access attempt is directly from 3070** top-level SQL code. 3071*/ 3072/******************************************* 3rd ************ 4th ***********/ 3073#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 3074#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 3075#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 3076#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 3077#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 3078#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 3079#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 3080#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 3081#define SQLITE_DELETE 9 /* Table Name NULL */ 3082#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 3083#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 3084#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 3085#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 3086#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 3087#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 3088#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 3089#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 3090#define SQLITE_INSERT 18 /* Table Name NULL */ 3091#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 3092#define SQLITE_READ 20 /* Table Name Column Name */ 3093#define SQLITE_SELECT 21 /* NULL NULL */ 3094#define SQLITE_TRANSACTION 22 /* Operation NULL */ 3095#define SQLITE_UPDATE 23 /* Table Name Column Name */ 3096#define SQLITE_ATTACH 24 /* Filename NULL */ 3097#define SQLITE_DETACH 25 /* Database Name NULL */ 3098#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 3099#define SQLITE_REINDEX 27 /* Index Name NULL */ 3100#define SQLITE_ANALYZE 28 /* Table Name NULL */ 3101#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 3102#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 3103#define SQLITE_FUNCTION 31 /* NULL Function Name */ 3104#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 3105#define SQLITE_COPY 0 /* No longer used */ 3106#define SQLITE_RECURSIVE 33 /* NULL NULL */ 3107 3108/* 3109** CAPI3REF: Tracing And Profiling Functions 3110** METHOD: sqlite3 3111** 3112** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 3113** instead of the routines described here. 3114** 3115** These routines register callback functions that can be used for 3116** tracing and profiling the execution of SQL statements. 3117** 3118** ^The callback function registered by sqlite3_trace() is invoked at 3119** various times when an SQL statement is being run by [sqlite3_step()]. 3120** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 3121** SQL statement text as the statement first begins executing. 3122** ^(Additional sqlite3_trace() callbacks might occur 3123** as each triggered subprogram is entered. The callbacks for triggers 3124** contain a UTF-8 SQL comment that identifies the trigger.)^ 3125** 3126** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 3127** the length of [bound parameter] expansion in the output of sqlite3_trace(). 3128** 3129** ^The callback function registered by sqlite3_profile() is invoked 3130** as each SQL statement finishes. ^The profile callback contains 3131** the original statement text and an estimate of wall-clock time 3132** of how long that statement took to run. ^The profile callback 3133** time is in units of nanoseconds, however the current implementation 3134** is only capable of millisecond resolution so the six least significant 3135** digits in the time are meaningless. Future versions of SQLite 3136** might provide greater resolution on the profiler callback. Invoking 3137** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the 3138** profile callback. 3139*/ 3140SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 3141 void(*xTrace)(void*,const char*), void*); 3142SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 3143 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 3144 3145/* 3146** CAPI3REF: SQL Trace Event Codes 3147** KEYWORDS: SQLITE_TRACE 3148** 3149** These constants identify classes of events that can be monitored 3150** using the [sqlite3_trace_v2()] tracing logic. The M argument 3151** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 3152** the following constants. ^The first argument to the trace callback 3153** is one of the following constants. 3154** 3155** New tracing constants may be added in future releases. 3156** 3157** ^A trace callback has four arguments: xCallback(T,C,P,X). 3158** ^The T argument is one of the integer type codes above. 3159** ^The C argument is a copy of the context pointer passed in as the 3160** fourth argument to [sqlite3_trace_v2()]. 3161** The P and X arguments are pointers whose meanings depend on T. 3162** 3163** <dl> 3164** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 3165** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 3166** first begins running and possibly at other times during the 3167** execution of the prepared statement, such as at the start of each 3168** trigger subprogram. ^The P argument is a pointer to the 3169** [prepared statement]. ^The X argument is a pointer to a string which 3170** is the unexpanded SQL text of the prepared statement or an SQL comment 3171** that indicates the invocation of a trigger. ^The callback can compute 3172** the same text that would have been returned by the legacy [sqlite3_trace()] 3173** interface by using the X argument when X begins with "--" and invoking 3174** [sqlite3_expanded_sql(P)] otherwise. 3175** 3176** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 3177** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 3178** information as is provided by the [sqlite3_profile()] callback. 3179** ^The P argument is a pointer to the [prepared statement] and the 3180** X argument points to a 64-bit integer which is the estimated of 3181** the number of nanosecond that the prepared statement took to run. 3182** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 3183** 3184** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 3185** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 3186** statement generates a single row of result. 3187** ^The P argument is a pointer to the [prepared statement] and the 3188** X argument is unused. 3189** 3190** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 3191** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 3192** connection closes. 3193** ^The P argument is a pointer to the [database connection] object 3194** and the X argument is unused. 3195** </dl> 3196*/ 3197#define SQLITE_TRACE_STMT 0x01 3198#define SQLITE_TRACE_PROFILE 0x02 3199#define SQLITE_TRACE_ROW 0x04 3200#define SQLITE_TRACE_CLOSE 0x08 3201 3202/* 3203** CAPI3REF: SQL Trace Hook 3204** METHOD: sqlite3 3205** 3206** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3207** function X against [database connection] D, using property mask M 3208** and context pointer P. ^If the X callback is 3209** NULL or if the M mask is zero, then tracing is disabled. The 3210** M argument should be the bitwise OR-ed combination of 3211** zero or more [SQLITE_TRACE] constants. 3212** 3213** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3214** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3215** 3216** ^The X callback is invoked whenever any of the events identified by 3217** mask M occur. ^The integer return value from the callback is currently 3218** ignored, though this may change in future releases. Callback 3219** implementations should return zero to ensure future compatibility. 3220** 3221** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3222** ^The T argument is one of the [SQLITE_TRACE] 3223** constants to indicate why the callback was invoked. 3224** ^The C argument is a copy of the context pointer. 3225** The P and X arguments are pointers whose meanings depend on T. 3226** 3227** The sqlite3_trace_v2() interface is intended to replace the legacy 3228** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3229** are deprecated. 3230*/ 3231int sqlite3_trace_v2( 3232 sqlite3*, 3233 unsigned uMask, 3234 int(*xCallback)(unsigned,void*,void*,void*), 3235 void *pCtx 3236); 3237 3238/* 3239** CAPI3REF: Query Progress Callbacks 3240** METHOD: sqlite3 3241** 3242** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3243** function X to be invoked periodically during long running calls to 3244** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3245** database connection D. An example use for this 3246** interface is to keep a GUI updated during a large query. 3247** 3248** ^The parameter P is passed through as the only parameter to the 3249** callback function X. ^The parameter N is the approximate number of 3250** [virtual machine instructions] that are evaluated between successive 3251** invocations of the callback X. ^If N is less than one then the progress 3252** handler is disabled. 3253** 3254** ^Only a single progress handler may be defined at one time per 3255** [database connection]; setting a new progress handler cancels the 3256** old one. ^Setting parameter X to NULL disables the progress handler. 3257** ^The progress handler is also disabled by setting N to a value less 3258** than 1. 3259** 3260** ^If the progress callback returns non-zero, the operation is 3261** interrupted. This feature can be used to implement a 3262** "Cancel" button on a GUI progress dialog box. 3263** 3264** The progress handler callback must not do anything that will modify 3265** the database connection that invoked the progress handler. 3266** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3267** database connections for the meaning of "modify" in this paragraph. 3268** 3269*/ 3270void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3271 3272/* 3273** CAPI3REF: Opening A New Database Connection 3274** CONSTRUCTOR: sqlite3 3275** 3276** ^These routines open an SQLite database file as specified by the 3277** filename argument. ^The filename argument is interpreted as UTF-8 for 3278** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3279** order for sqlite3_open16(). ^(A [database connection] handle is usually 3280** returned in *ppDb, even if an error occurs. The only exception is that 3281** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3282** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3283** object.)^ ^(If the database is opened (and/or created) successfully, then 3284** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3285** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3286** an English language description of the error following a failure of any 3287** of the sqlite3_open() routines. 3288** 3289** ^The default encoding will be UTF-8 for databases created using 3290** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3291** created using sqlite3_open16() will be UTF-16 in the native byte order. 3292** 3293** Whether or not an error occurs when it is opened, resources 3294** associated with the [database connection] handle should be released by 3295** passing it to [sqlite3_close()] when it is no longer required. 3296** 3297** The sqlite3_open_v2() interface works like sqlite3_open() 3298** except that it accepts two additional parameters for additional control 3299** over the new database connection. ^(The flags parameter to 3300** sqlite3_open_v2() must include, at a minimum, one of the following 3301** three flag combinations:)^ 3302** 3303** <dl> 3304** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3305** <dd>The database is opened in read-only mode. If the database does not 3306** already exist, an error is returned.</dd>)^ 3307** 3308** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3309** <dd>The database is opened for reading and writing if possible, or reading 3310** only if the file is write protected by the operating system. In either 3311** case the database must already exist, otherwise an error is returned.</dd>)^ 3312** 3313** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3314** <dd>The database is opened for reading and writing, and is created if 3315** it does not already exist. This is the behavior that is always used for 3316** sqlite3_open() and sqlite3_open16().</dd>)^ 3317** </dl> 3318** 3319** In addition to the required flags, the following optional flags are 3320** also supported: 3321** 3322** <dl> 3323** ^(<dt>[SQLITE_OPEN_URI]</dt> 3324** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^ 3325** 3326** ^(<dt>[SQLITE_OPEN_MEMORY]</dt> 3327** <dd>The database will be opened as an in-memory database. The database 3328** is named by the "filename" argument for the purposes of cache-sharing, 3329** if shared cache mode is enabled, but the "filename" is otherwise ignored. 3330** </dd>)^ 3331** 3332** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt> 3333** <dd>The new database connection will use the "multi-thread" 3334** [threading mode].)^ This means that separate threads are allowed 3335** to use SQLite at the same time, as long as each thread is using 3336** a different [database connection]. 3337** 3338** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt> 3339** <dd>The new database connection will use the "serialized" 3340** [threading mode].)^ This means the multiple threads can safely 3341** attempt to use the same database connection at the same time. 3342** (Mutexes will block any actual concurrency, but in this mode 3343** there is no harm in trying.) 3344** 3345** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt> 3346** <dd>The database is opened [shared cache] enabled, overriding 3347** the default shared cache setting provided by 3348** [sqlite3_enable_shared_cache()].)^ 3349** 3350** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt> 3351** <dd>The database is opened [shared cache] disabled, overriding 3352** the default shared cache setting provided by 3353** [sqlite3_enable_shared_cache()].)^ 3354** 3355** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt> 3356** <dd>The database filename is not allowed to be a symbolic link</dd> 3357** </dl>)^ 3358** 3359** If the 3rd parameter to sqlite3_open_v2() is not one of the 3360** required combinations shown above optionally combined with other 3361** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3362** then the behavior is undefined. 3363** 3364** ^The fourth parameter to sqlite3_open_v2() is the name of the 3365** [sqlite3_vfs] object that defines the operating system interface that 3366** the new database connection should use. ^If the fourth parameter is 3367** a NULL pointer then the default [sqlite3_vfs] object is used. 3368** 3369** ^If the filename is ":memory:", then a private, temporary in-memory database 3370** is created for the connection. ^This in-memory database will vanish when 3371** the database connection is closed. Future versions of SQLite might 3372** make use of additional special filenames that begin with the ":" character. 3373** It is recommended that when a database filename actually does begin with 3374** a ":" character you should prefix the filename with a pathname such as 3375** "./" to avoid ambiguity. 3376** 3377** ^If the filename is an empty string, then a private, temporary 3378** on-disk database will be created. ^This private database will be 3379** automatically deleted as soon as the database connection is closed. 3380** 3381** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3382** 3383** ^If [URI filename] interpretation is enabled, and the filename argument 3384** begins with "file:", then the filename is interpreted as a URI. ^URI 3385** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3386** set in the third argument to sqlite3_open_v2(), or if it has 3387** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3388** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3389** URI filename interpretation is turned off 3390** by default, but future releases of SQLite might enable URI filename 3391** interpretation by default. See "[URI filenames]" for additional 3392** information. 3393** 3394** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3395** authority, then it must be either an empty string or the string 3396** "localhost". ^If the authority is not an empty string or "localhost", an 3397** error is returned to the caller. ^The fragment component of a URI, if 3398** present, is ignored. 3399** 3400** ^SQLite uses the path component of the URI as the name of the disk file 3401** which contains the database. ^If the path begins with a '/' character, 3402** then it is interpreted as an absolute path. ^If the path does not begin 3403** with a '/' (meaning that the authority section is omitted from the URI) 3404** then the path is interpreted as a relative path. 3405** ^(On windows, the first component of an absolute path 3406** is a drive specification (e.g. "C:").)^ 3407** 3408** [[core URI query parameters]] 3409** The query component of a URI may contain parameters that are interpreted 3410** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3411** SQLite and its built-in [VFSes] interpret the 3412** following query parameters: 3413** 3414** <ul> 3415** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3416** a VFS object that provides the operating system interface that should 3417** be used to access the database file on disk. ^If this option is set to 3418** an empty string the default VFS object is used. ^Specifying an unknown 3419** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3420** present, then the VFS specified by the option takes precedence over 3421** the value passed as the fourth parameter to sqlite3_open_v2(). 3422** 3423** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3424** "rwc", or "memory". Attempting to set it to any other value is 3425** an error)^. 3426** ^If "ro" is specified, then the database is opened for read-only 3427** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3428** third argument to sqlite3_open_v2(). ^If the mode option is set to 3429** "rw", then the database is opened for read-write (but not create) 3430** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3431** been set. ^Value "rwc" is equivalent to setting both 3432** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3433** set to "memory" then a pure [in-memory database] that never reads 3434** or writes from disk is used. ^It is an error to specify a value for 3435** the mode parameter that is less restrictive than that specified by 3436** the flags passed in the third parameter to sqlite3_open_v2(). 3437** 3438** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3439** "private". ^Setting it to "shared" is equivalent to setting the 3440** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3441** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3442** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3443** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3444** a URI filename, its value overrides any behavior requested by setting 3445** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3446** 3447** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3448** [powersafe overwrite] property does or does not apply to the 3449** storage media on which the database file resides. 3450** 3451** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3452** which if set disables file locking in rollback journal modes. This 3453** is useful for accessing a database on a filesystem that does not 3454** support locking. Caution: Database corruption might result if two 3455** or more processes write to the same database and any one of those 3456** processes uses nolock=1. 3457** 3458** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3459** parameter that indicates that the database file is stored on 3460** read-only media. ^When immutable is set, SQLite assumes that the 3461** database file cannot be changed, even by a process with higher 3462** privilege, and so the database is opened read-only and all locking 3463** and change detection is disabled. Caution: Setting the immutable 3464** property on a database file that does in fact change can result 3465** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3466** See also: [SQLITE_IOCAP_IMMUTABLE]. 3467** 3468** </ul> 3469** 3470** ^Specifying an unknown parameter in the query component of a URI is not an 3471** error. Future versions of SQLite might understand additional query 3472** parameters. See "[query parameters with special meaning to SQLite]" for 3473** additional information. 3474** 3475** [[URI filename examples]] <h3>URI filename examples</h3> 3476** 3477** <table border="1" align=center cellpadding=5> 3478** <tr><th> URI filenames <th> Results 3479** <tr><td> file:data.db <td> 3480** Open the file "data.db" in the current directory. 3481** <tr><td> file:/home/fred/data.db<br> 3482** file:///home/fred/data.db <br> 3483** file://localhost/home/fred/data.db <br> <td> 3484** Open the database file "/home/fred/data.db". 3485** <tr><td> file://darkstar/home/fred/data.db <td> 3486** An error. "darkstar" is not a recognized authority. 3487** <tr><td style="white-space:nowrap"> 3488** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3489** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3490** C:. Note that the %20 escaping in this example is not strictly 3491** necessary - space characters can be used literally 3492** in URI filenames. 3493** <tr><td> file:data.db?mode=ro&cache=private <td> 3494** Open file "data.db" in the current directory for read-only access. 3495** Regardless of whether or not shared-cache mode is enabled by 3496** default, use a private cache. 3497** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3498** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3499** that uses dot-files in place of posix advisory locking. 3500** <tr><td> file:data.db?mode=readonly <td> 3501** An error. "readonly" is not a valid option for the "mode" parameter. 3502** Use "ro" instead: "file:data.db?mode=ro". 3503** </table> 3504** 3505** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3506** query components of a URI. A hexadecimal escape sequence consists of a 3507** percent sign - "%" - followed by exactly two hexadecimal digits 3508** specifying an octet value. ^Before the path or query components of a 3509** URI filename are interpreted, they are encoded using UTF-8 and all 3510** hexadecimal escape sequences replaced by a single byte containing the 3511** corresponding octet. If this process generates an invalid UTF-8 encoding, 3512** the results are undefined. 3513** 3514** <b>Note to Windows users:</b> The encoding used for the filename argument 3515** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3516** codepage is currently defined. Filenames containing international 3517** characters must be converted to UTF-8 prior to passing them into 3518** sqlite3_open() or sqlite3_open_v2(). 3519** 3520** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3521** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3522** features that require the use of temporary files may fail. 3523** 3524** See also: [sqlite3_temp_directory] 3525*/ 3526int sqlite3_open( 3527 const char *filename, /* Database filename (UTF-8) */ 3528 sqlite3 **ppDb /* OUT: SQLite db handle */ 3529); 3530int sqlite3_open16( 3531 const void *filename, /* Database filename (UTF-16) */ 3532 sqlite3 **ppDb /* OUT: SQLite db handle */ 3533); 3534int sqlite3_open_v2( 3535 const char *filename, /* Database filename (UTF-8) */ 3536 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3537 int flags, /* Flags */ 3538 const char *zVfs /* Name of VFS module to use */ 3539); 3540 3541/* 3542** CAPI3REF: Obtain Values For URI Parameters 3543** 3544** These are utility routines, useful to [VFS|custom VFS implementations], 3545** that check if a database file was a URI that contained a specific query 3546** parameter, and if so obtains the value of that query parameter. 3547** 3548** The first parameter to these interfaces (hereafter referred to 3549** as F) must be one of: 3550** <ul> 3551** <li> A database filename pointer created by the SQLite core and 3552** passed into the xOpen() method of a VFS implemention, or 3553** <li> A filename obtained from [sqlite3_db_filename()], or 3554** <li> A new filename constructed using [sqlite3_create_filename()]. 3555** </ul> 3556** If the F parameter is not one of the above, then the behavior is 3557** undefined and probably undesirable. Older versions of SQLite were 3558** more tolerant of invalid F parameters than newer versions. 3559** 3560** If F is a suitable filename (as described in the previous paragraph) 3561** and if P is the name of the query parameter, then 3562** sqlite3_uri_parameter(F,P) returns the value of the P 3563** parameter if it exists or a NULL pointer if P does not appear as a 3564** query parameter on F. If P is a query parameter of F and it 3565** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3566** a pointer to an empty string. 3567** 3568** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3569** parameter and returns true (1) or false (0) according to the value 3570** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3571** value of query parameter P is one of "yes", "true", or "on" in any 3572** case or if the value begins with a non-zero number. The 3573** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3574** query parameter P is one of "no", "false", or "off" in any case or 3575** if the value begins with a numeric zero. If P is not a query 3576** parameter on F or if the value of P does not match any of the 3577** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3578** 3579** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3580** 64-bit signed integer and returns that integer, or D if P does not 3581** exist. If the value of P is something other than an integer, then 3582** zero is returned. 3583** 3584** The sqlite3_uri_key(F,N) returns a pointer to the name (not 3585** the value) of the N-th query parameter for filename F, or a NULL 3586** pointer if N is less than zero or greater than the number of query 3587** parameters minus 1. The N value is zero-based so N should be 0 to obtain 3588** the name of the first query parameter, 1 for the second parameter, and 3589** so forth. 3590** 3591** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3592** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3593** is not a database file pathname pointer that the SQLite core passed 3594** into the xOpen VFS method, then the behavior of this routine is undefined 3595** and probably undesirable. 3596** 3597** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F 3598** parameter can also be the name of a rollback journal file or WAL file 3599** in addition to the main database file. Prior to version 3.31.0, these 3600** routines would only work if F was the name of the main database file. 3601** When the F parameter is the name of the rollback journal or WAL file, 3602** it has access to all the same query parameters as were found on the 3603** main database file. 3604** 3605** See the [URI filename] documentation for additional information. 3606*/ 3607const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3608int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3609sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3610const char *sqlite3_uri_key(const char *zFilename, int N); 3611 3612/* 3613** CAPI3REF: Translate filenames 3614** 3615** These routines are available to [VFS|custom VFS implementations] for 3616** translating filenames between the main database file, the journal file, 3617** and the WAL file. 3618** 3619** If F is the name of an sqlite database file, journal file, or WAL file 3620** passed by the SQLite core into the VFS, then sqlite3_filename_database(F) 3621** returns the name of the corresponding database file. 3622** 3623** If F is the name of an sqlite database file, journal file, or WAL file 3624** passed by the SQLite core into the VFS, or if F is a database filename 3625** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F) 3626** returns the name of the corresponding rollback journal file. 3627** 3628** If F is the name of an sqlite database file, journal file, or WAL file 3629** that was passed by the SQLite core into the VFS, or if F is a database 3630** filename obtained from [sqlite3_db_filename()], then 3631** sqlite3_filename_wal(F) returns the name of the corresponding 3632** WAL file. 3633** 3634** In all of the above, if F is not the name of a database, journal or WAL 3635** filename passed into the VFS from the SQLite core and F is not the 3636** return value from [sqlite3_db_filename()], then the result is 3637** undefined and is likely a memory access violation. 3638*/ 3639const char *sqlite3_filename_database(const char*); 3640const char *sqlite3_filename_journal(const char*); 3641const char *sqlite3_filename_wal(const char*); 3642 3643/* 3644** CAPI3REF: Database File Corresponding To A Journal 3645** 3646** ^If X is the name of a rollback or WAL-mode journal file that is 3647** passed into the xOpen method of [sqlite3_vfs], then 3648** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file] 3649** object that represents the main database file. 3650** 3651** This routine is intended for use in custom [VFS] implementations 3652** only. It is not a general-purpose interface. 3653** The argument sqlite3_file_object(X) must be a filename pointer that 3654** has been passed into [sqlite3_vfs].xOpen method where the 3655** flags parameter to xOpen contains one of the bits 3656** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL]. Any other use 3657** of this routine results in undefined and probably undesirable 3658** behavior. 3659*/ 3660sqlite3_file *sqlite3_database_file_object(const char*); 3661 3662/* 3663** CAPI3REF: Create and Destroy VFS Filenames 3664** 3665** These interfces are provided for use by [VFS shim] implementations and 3666** are not useful outside of that context. 3667** 3668** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of 3669** database filename D with corresponding journal file J and WAL file W and 3670** with N URI parameters key/values pairs in the array P. The result from 3671** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that 3672** is safe to pass to routines like: 3673** <ul> 3674** <li> [sqlite3_uri_parameter()], 3675** <li> [sqlite3_uri_boolean()], 3676** <li> [sqlite3_uri_int64()], 3677** <li> [sqlite3_uri_key()], 3678** <li> [sqlite3_filename_database()], 3679** <li> [sqlite3_filename_journal()], or 3680** <li> [sqlite3_filename_wal()]. 3681** </ul> 3682** If a memory allocation error occurs, sqlite3_create_filename() might 3683** return a NULL pointer. The memory obtained from sqlite3_create_filename(X) 3684** must be released by a corresponding call to sqlite3_free_filename(Y). 3685** 3686** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array 3687** of 2*N pointers to strings. Each pair of pointers in this array corresponds 3688** to a key and value for a query parameter. The P parameter may be a NULL 3689** pointer if N is zero. None of the 2*N pointers in the P array may be 3690** NULL pointers and key pointers should not be empty strings. 3691** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may 3692** be NULL pointers, though they can be empty strings. 3693** 3694** The sqlite3_free_filename(Y) routine releases a memory allocation 3695** previously obtained from sqlite3_create_filename(). Invoking 3696** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op. 3697** 3698** If the Y parameter to sqlite3_free_filename(Y) is anything other 3699** than a NULL pointer or a pointer previously acquired from 3700** sqlite3_create_filename(), then bad things such as heap 3701** corruption or segfaults may occur. The value Y should not be 3702** used again after sqlite3_free_filename(Y) has been called. This means 3703** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y, 3704** then the corresponding [sqlite3_module.xClose() method should also be 3705** invoked prior to calling sqlite3_free_filename(Y). 3706*/ 3707char *sqlite3_create_filename( 3708 const char *zDatabase, 3709 const char *zJournal, 3710 const char *zWal, 3711 int nParam, 3712 const char **azParam 3713); 3714void sqlite3_free_filename(char*); 3715 3716/* 3717** CAPI3REF: Error Codes And Messages 3718** METHOD: sqlite3 3719** 3720** ^If the most recent sqlite3_* API call associated with 3721** [database connection] D failed, then the sqlite3_errcode(D) interface 3722** returns the numeric [result code] or [extended result code] for that 3723** API call. 3724** ^The sqlite3_extended_errcode() 3725** interface is the same except that it always returns the 3726** [extended result code] even when extended result codes are 3727** disabled. 3728** 3729** The values returned by sqlite3_errcode() and/or 3730** sqlite3_extended_errcode() might change with each API call. 3731** Except, there are some interfaces that are guaranteed to never 3732** change the value of the error code. The error-code preserving 3733** interfaces are: 3734** 3735** <ul> 3736** <li> sqlite3_errcode() 3737** <li> sqlite3_extended_errcode() 3738** <li> sqlite3_errmsg() 3739** <li> sqlite3_errmsg16() 3740** </ul> 3741** 3742** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3743** text that describes the error, as either UTF-8 or UTF-16 respectively. 3744** ^(Memory to hold the error message string is managed internally. 3745** The application does not need to worry about freeing the result. 3746** However, the error string might be overwritten or deallocated by 3747** subsequent calls to other SQLite interface functions.)^ 3748** 3749** ^The sqlite3_errstr() interface returns the English-language text 3750** that describes the [result code], as UTF-8. 3751** ^(Memory to hold the error message string is managed internally 3752** and must not be freed by the application)^. 3753** 3754** When the serialized [threading mode] is in use, it might be the 3755** case that a second error occurs on a separate thread in between 3756** the time of the first error and the call to these interfaces. 3757** When that happens, the second error will be reported since these 3758** interfaces always report the most recent result. To avoid 3759** this, each thread can obtain exclusive use of the [database connection] D 3760** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3761** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3762** all calls to the interfaces listed here are completed. 3763** 3764** If an interface fails with SQLITE_MISUSE, that means the interface 3765** was invoked incorrectly by the application. In that case, the 3766** error code and message may or may not be set. 3767*/ 3768int sqlite3_errcode(sqlite3 *db); 3769int sqlite3_extended_errcode(sqlite3 *db); 3770const char *sqlite3_errmsg(sqlite3*); 3771const void *sqlite3_errmsg16(sqlite3*); 3772const char *sqlite3_errstr(int); 3773 3774/* 3775** CAPI3REF: Prepared Statement Object 3776** KEYWORDS: {prepared statement} {prepared statements} 3777** 3778** An instance of this object represents a single SQL statement that 3779** has been compiled into binary form and is ready to be evaluated. 3780** 3781** Think of each SQL statement as a separate computer program. The 3782** original SQL text is source code. A prepared statement object 3783** is the compiled object code. All SQL must be converted into a 3784** prepared statement before it can be run. 3785** 3786** The life-cycle of a prepared statement object usually goes like this: 3787** 3788** <ol> 3789** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3790** <li> Bind values to [parameters] using the sqlite3_bind_*() 3791** interfaces. 3792** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3793** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3794** to step 2. Do this zero or more times. 3795** <li> Destroy the object using [sqlite3_finalize()]. 3796** </ol> 3797*/ 3798typedef struct sqlite3_stmt sqlite3_stmt; 3799 3800/* 3801** CAPI3REF: Run-time Limits 3802** METHOD: sqlite3 3803** 3804** ^(This interface allows the size of various constructs to be limited 3805** on a connection by connection basis. The first parameter is the 3806** [database connection] whose limit is to be set or queried. The 3807** second parameter is one of the [limit categories] that define a 3808** class of constructs to be size limited. The third parameter is the 3809** new limit for that construct.)^ 3810** 3811** ^If the new limit is a negative number, the limit is unchanged. 3812** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3813** [limits | hard upper bound] 3814** set at compile-time by a C preprocessor macro called 3815** [limits | SQLITE_MAX_<i>NAME</i>]. 3816** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3817** ^Attempts to increase a limit above its hard upper bound are 3818** silently truncated to the hard upper bound. 3819** 3820** ^Regardless of whether or not the limit was changed, the 3821** [sqlite3_limit()] interface returns the prior value of the limit. 3822** ^Hence, to find the current value of a limit without changing it, 3823** simply invoke this interface with the third parameter set to -1. 3824** 3825** Run-time limits are intended for use in applications that manage 3826** both their own internal database and also databases that are controlled 3827** by untrusted external sources. An example application might be a 3828** web browser that has its own databases for storing history and 3829** separate databases controlled by JavaScript applications downloaded 3830** off the Internet. The internal databases can be given the 3831** large, default limits. Databases managed by external sources can 3832** be given much smaller limits designed to prevent a denial of service 3833** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3834** interface to further control untrusted SQL. The size of the database 3835** created by an untrusted script can be contained using the 3836** [max_page_count] [PRAGMA]. 3837** 3838** New run-time limit categories may be added in future releases. 3839*/ 3840int sqlite3_limit(sqlite3*, int id, int newVal); 3841 3842/* 3843** CAPI3REF: Run-Time Limit Categories 3844** KEYWORDS: {limit category} {*limit categories} 3845** 3846** These constants define various performance limits 3847** that can be lowered at run-time using [sqlite3_limit()]. 3848** The synopsis of the meanings of the various limits is shown below. 3849** Additional information is available at [limits | Limits in SQLite]. 3850** 3851** <dl> 3852** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3853** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3854** 3855** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3856** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3857** 3858** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3859** <dd>The maximum number of columns in a table definition or in the 3860** result set of a [SELECT] or the maximum number of columns in an index 3861** or in an ORDER BY or GROUP BY clause.</dd>)^ 3862** 3863** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3864** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3865** 3866** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3867** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3868** 3869** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3870** <dd>The maximum number of instructions in a virtual machine program 3871** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3872** the equivalent tries to allocate space for more than this many opcodes 3873** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3874** 3875** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3876** <dd>The maximum number of arguments on a function.</dd>)^ 3877** 3878** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3879** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3880** 3881** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3882** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3883** <dd>The maximum length of the pattern argument to the [LIKE] or 3884** [GLOB] operators.</dd>)^ 3885** 3886** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3887** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3888** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3889** 3890** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3891** <dd>The maximum depth of recursion for triggers.</dd>)^ 3892** 3893** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3894** <dd>The maximum number of auxiliary worker threads that a single 3895** [prepared statement] may start.</dd>)^ 3896** </dl> 3897*/ 3898#define SQLITE_LIMIT_LENGTH 0 3899#define SQLITE_LIMIT_SQL_LENGTH 1 3900#define SQLITE_LIMIT_COLUMN 2 3901#define SQLITE_LIMIT_EXPR_DEPTH 3 3902#define SQLITE_LIMIT_COMPOUND_SELECT 4 3903#define SQLITE_LIMIT_VDBE_OP 5 3904#define SQLITE_LIMIT_FUNCTION_ARG 6 3905#define SQLITE_LIMIT_ATTACHED 7 3906#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3907#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3908#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3909#define SQLITE_LIMIT_WORKER_THREADS 11 3910 3911/* 3912** CAPI3REF: Prepare Flags 3913** 3914** These constants define various flags that can be passed into 3915** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3916** [sqlite3_prepare16_v3()] interfaces. 3917** 3918** New flags may be added in future releases of SQLite. 3919** 3920** <dl> 3921** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3922** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3923** that the prepared statement will be retained for a long time and 3924** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3925** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3926** be used just once or at most a few times and then destroyed using 3927** [sqlite3_finalize()] relatively soon. The current implementation acts 3928** on this hint by avoiding the use of [lookaside memory] so as not to 3929** deplete the limited store of lookaside memory. Future versions of 3930** SQLite may act on this hint differently. 3931** 3932** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt> 3933** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used 3934** to be required for any prepared statement that wanted to use the 3935** [sqlite3_normalized_sql()] interface. However, the 3936** [sqlite3_normalized_sql()] interface is now available to all 3937** prepared statements, regardless of whether or not they use this 3938** flag. 3939** 3940** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt> 3941** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler 3942** to return an error (error code SQLITE_ERROR) if the statement uses 3943** any virtual tables. 3944** </dl> 3945*/ 3946#define SQLITE_PREPARE_PERSISTENT 0x01 3947#define SQLITE_PREPARE_NORMALIZE 0x02 3948#define SQLITE_PREPARE_NO_VTAB 0x04 3949 3950/* 3951** CAPI3REF: Compiling An SQL Statement 3952** KEYWORDS: {SQL statement compiler} 3953** METHOD: sqlite3 3954** CONSTRUCTOR: sqlite3_stmt 3955** 3956** To execute an SQL statement, it must first be compiled into a byte-code 3957** program using one of these routines. Or, in other words, these routines 3958** are constructors for the [prepared statement] object. 3959** 3960** The preferred routine to use is [sqlite3_prepare_v2()]. The 3961** [sqlite3_prepare()] interface is legacy and should be avoided. 3962** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3963** for special purposes. 3964** 3965** The use of the UTF-8 interfaces is preferred, as SQLite currently 3966** does all parsing using UTF-8. The UTF-16 interfaces are provided 3967** as a convenience. The UTF-16 interfaces work by converting the 3968** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3969** 3970** The first argument, "db", is a [database connection] obtained from a 3971** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3972** [sqlite3_open16()]. The database connection must not have been closed. 3973** 3974** The second argument, "zSql", is the statement to be compiled, encoded 3975** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3976** and sqlite3_prepare_v3() 3977** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3978** and sqlite3_prepare16_v3() use UTF-16. 3979** 3980** ^If the nByte argument is negative, then zSql is read up to the 3981** first zero terminator. ^If nByte is positive, then it is the 3982** number of bytes read from zSql. ^If nByte is zero, then no prepared 3983** statement is generated. 3984** If the caller knows that the supplied string is nul-terminated, then 3985** there is a small performance advantage to passing an nByte parameter that 3986** is the number of bytes in the input string <i>including</i> 3987** the nul-terminator. 3988** 3989** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3990** past the end of the first SQL statement in zSql. These routines only 3991** compile the first statement in zSql, so *pzTail is left pointing to 3992** what remains uncompiled. 3993** 3994** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3995** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3996** to NULL. ^If the input text contains no SQL (if the input is an empty 3997** string or a comment) then *ppStmt is set to NULL. 3998** The calling procedure is responsible for deleting the compiled 3999** SQL statement using [sqlite3_finalize()] after it has finished with it. 4000** ppStmt may not be NULL. 4001** 4002** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 4003** otherwise an [error code] is returned. 4004** 4005** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 4006** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 4007** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 4008** are retained for backwards compatibility, but their use is discouraged. 4009** ^In the "vX" interfaces, the prepared statement 4010** that is returned (the [sqlite3_stmt] object) contains a copy of the 4011** original SQL text. This causes the [sqlite3_step()] interface to 4012** behave differently in three ways: 4013** 4014** <ol> 4015** <li> 4016** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 4017** always used to do, [sqlite3_step()] will automatically recompile the SQL 4018** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 4019** retries will occur before sqlite3_step() gives up and returns an error. 4020** </li> 4021** 4022** <li> 4023** ^When an error occurs, [sqlite3_step()] will return one of the detailed 4024** [error codes] or [extended error codes]. ^The legacy behavior was that 4025** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 4026** and the application would have to make a second call to [sqlite3_reset()] 4027** in order to find the underlying cause of the problem. With the "v2" prepare 4028** interfaces, the underlying reason for the error is returned immediately. 4029** </li> 4030** 4031** <li> 4032** ^If the specific value bound to a [parameter | host parameter] in the 4033** WHERE clause might influence the choice of query plan for a statement, 4034** then the statement will be automatically recompiled, as if there had been 4035** a schema change, on the first [sqlite3_step()] call following any change 4036** to the [sqlite3_bind_text | bindings] of that [parameter]. 4037** ^The specific value of a WHERE-clause [parameter] might influence the 4038** choice of query plan if the parameter is the left-hand side of a [LIKE] 4039** or [GLOB] operator or if the parameter is compared to an indexed column 4040** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled. 4041** </li> 4042** </ol> 4043** 4044** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 4045** the extra prepFlags parameter, which is a bit array consisting of zero or 4046** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 4047** sqlite3_prepare_v2() interface works exactly the same as 4048** sqlite3_prepare_v3() with a zero prepFlags parameter. 4049*/ 4050int sqlite3_prepare( 4051 sqlite3 *db, /* Database handle */ 4052 const char *zSql, /* SQL statement, UTF-8 encoded */ 4053 int nByte, /* Maximum length of zSql in bytes. */ 4054 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4055 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4056); 4057int sqlite3_prepare_v2( 4058 sqlite3 *db, /* Database handle */ 4059 const char *zSql, /* SQL statement, UTF-8 encoded */ 4060 int nByte, /* Maximum length of zSql in bytes. */ 4061 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4062 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4063); 4064int sqlite3_prepare_v3( 4065 sqlite3 *db, /* Database handle */ 4066 const char *zSql, /* SQL statement, UTF-8 encoded */ 4067 int nByte, /* Maximum length of zSql in bytes. */ 4068 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4069 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4070 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4071); 4072int sqlite3_prepare16( 4073 sqlite3 *db, /* Database handle */ 4074 const void *zSql, /* SQL statement, UTF-16 encoded */ 4075 int nByte, /* Maximum length of zSql in bytes. */ 4076 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4077 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4078); 4079int sqlite3_prepare16_v2( 4080 sqlite3 *db, /* Database handle */ 4081 const void *zSql, /* SQL statement, UTF-16 encoded */ 4082 int nByte, /* Maximum length of zSql in bytes. */ 4083 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4084 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4085); 4086int sqlite3_prepare16_v3( 4087 sqlite3 *db, /* Database handle */ 4088 const void *zSql, /* SQL statement, UTF-16 encoded */ 4089 int nByte, /* Maximum length of zSql in bytes. */ 4090 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4091 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4092 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4093); 4094 4095/* 4096** CAPI3REF: Retrieving Statement SQL 4097** METHOD: sqlite3_stmt 4098** 4099** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 4100** SQL text used to create [prepared statement] P if P was 4101** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 4102** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4103** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 4104** string containing the SQL text of prepared statement P with 4105** [bound parameters] expanded. 4106** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8 4107** string containing the normalized SQL text of prepared statement P. The 4108** semantics used to normalize a SQL statement are unspecified and subject 4109** to change. At a minimum, literal values will be replaced with suitable 4110** placeholders. 4111** 4112** ^(For example, if a prepared statement is created using the SQL 4113** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 4114** and parameter :xyz is unbound, then sqlite3_sql() will return 4115** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 4116** will return "SELECT 2345,NULL".)^ 4117** 4118** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 4119** is available to hold the result, or if the result would exceed the 4120** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 4121** 4122** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 4123** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 4124** option causes sqlite3_expanded_sql() to always return NULL. 4125** 4126** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P) 4127** are managed by SQLite and are automatically freed when the prepared 4128** statement is finalized. 4129** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 4130** is obtained from [sqlite3_malloc()] and must be free by the application 4131** by passing it to [sqlite3_free()]. 4132*/ 4133const char *sqlite3_sql(sqlite3_stmt *pStmt); 4134char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 4135const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt); 4136 4137/* 4138** CAPI3REF: Determine If An SQL Statement Writes The Database 4139** METHOD: sqlite3_stmt 4140** 4141** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 4142** and only if the [prepared statement] X makes no direct changes to 4143** the content of the database file. 4144** 4145** Note that [application-defined SQL functions] or 4146** [virtual tables] might change the database indirectly as a side effect. 4147** ^(For example, if an application defines a function "eval()" that 4148** calls [sqlite3_exec()], then the following SQL statement would 4149** change the database file through side-effects: 4150** 4151** <blockquote><pre> 4152** SELECT eval('DELETE FROM t1') FROM t2; 4153** </pre></blockquote> 4154** 4155** But because the [SELECT] statement does not change the database file 4156** directly, sqlite3_stmt_readonly() would still return true.)^ 4157** 4158** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 4159** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 4160** since the statements themselves do not actually modify the database but 4161** rather they control the timing of when other statements modify the 4162** database. ^The [ATTACH] and [DETACH] statements also cause 4163** sqlite3_stmt_readonly() to return true since, while those statements 4164** change the configuration of a database connection, they do not make 4165** changes to the content of the database files on disk. 4166** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 4167** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 4168** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 4169** sqlite3_stmt_readonly() returns false for those commands. 4170*/ 4171int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 4172 4173/* 4174** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement 4175** METHOD: sqlite3_stmt 4176** 4177** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the 4178** prepared statement S is an EXPLAIN statement, or 2 if the 4179** statement S is an EXPLAIN QUERY PLAN. 4180** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is 4181** an ordinary statement or a NULL pointer. 4182*/ 4183int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt); 4184 4185/* 4186** CAPI3REF: Determine If A Prepared Statement Has Been Reset 4187** METHOD: sqlite3_stmt 4188** 4189** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 4190** [prepared statement] S has been stepped at least once using 4191** [sqlite3_step(S)] but has neither run to completion (returned 4192** [SQLITE_DONE] from [sqlite3_step(S)]) nor 4193** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 4194** interface returns false if S is a NULL pointer. If S is not a 4195** NULL pointer and is not a pointer to a valid [prepared statement] 4196** object, then the behavior is undefined and probably undesirable. 4197** 4198** This interface can be used in combination [sqlite3_next_stmt()] 4199** to locate all prepared statements associated with a database 4200** connection that are in need of being reset. This can be used, 4201** for example, in diagnostic routines to search for prepared 4202** statements that are holding a transaction open. 4203*/ 4204int sqlite3_stmt_busy(sqlite3_stmt*); 4205 4206/* 4207** CAPI3REF: Dynamically Typed Value Object 4208** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 4209** 4210** SQLite uses the sqlite3_value object to represent all values 4211** that can be stored in a database table. SQLite uses dynamic typing 4212** for the values it stores. ^Values stored in sqlite3_value objects 4213** can be integers, floating point values, strings, BLOBs, or NULL. 4214** 4215** An sqlite3_value object may be either "protected" or "unprotected". 4216** Some interfaces require a protected sqlite3_value. Other interfaces 4217** will accept either a protected or an unprotected sqlite3_value. 4218** Every interface that accepts sqlite3_value arguments specifies 4219** whether or not it requires a protected sqlite3_value. The 4220** [sqlite3_value_dup()] interface can be used to construct a new 4221** protected sqlite3_value from an unprotected sqlite3_value. 4222** 4223** The terms "protected" and "unprotected" refer to whether or not 4224** a mutex is held. An internal mutex is held for a protected 4225** sqlite3_value object but no mutex is held for an unprotected 4226** sqlite3_value object. If SQLite is compiled to be single-threaded 4227** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 4228** or if SQLite is run in one of reduced mutex modes 4229** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 4230** then there is no distinction between protected and unprotected 4231** sqlite3_value objects and they can be used interchangeably. However, 4232** for maximum code portability it is recommended that applications 4233** still make the distinction between protected and unprotected 4234** sqlite3_value objects even when not strictly required. 4235** 4236** ^The sqlite3_value objects that are passed as parameters into the 4237** implementation of [application-defined SQL functions] are protected. 4238** ^The sqlite3_value object returned by 4239** [sqlite3_column_value()] is unprotected. 4240** Unprotected sqlite3_value objects may only be used as arguments 4241** to [sqlite3_result_value()], [sqlite3_bind_value()], and 4242** [sqlite3_value_dup()]. 4243** The [sqlite3_value_blob | sqlite3_value_type()] family of 4244** interfaces require protected sqlite3_value objects. 4245*/ 4246typedef struct sqlite3_value sqlite3_value; 4247 4248/* 4249** CAPI3REF: SQL Function Context Object 4250** 4251** The context in which an SQL function executes is stored in an 4252** sqlite3_context object. ^A pointer to an sqlite3_context object 4253** is always first parameter to [application-defined SQL functions]. 4254** The application-defined SQL function implementation will pass this 4255** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 4256** [sqlite3_aggregate_context()], [sqlite3_user_data()], 4257** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 4258** and/or [sqlite3_set_auxdata()]. 4259*/ 4260typedef struct sqlite3_context sqlite3_context; 4261 4262/* 4263** CAPI3REF: Binding Values To Prepared Statements 4264** KEYWORDS: {host parameter} {host parameters} {host parameter name} 4265** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 4266** METHOD: sqlite3_stmt 4267** 4268** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 4269** literals may be replaced by a [parameter] that matches one of following 4270** templates: 4271** 4272** <ul> 4273** <li> ? 4274** <li> ?NNN 4275** <li> :VVV 4276** <li> @VVV 4277** <li> $VVV 4278** </ul> 4279** 4280** In the templates above, NNN represents an integer literal, 4281** and VVV represents an alphanumeric identifier.)^ ^The values of these 4282** parameters (also called "host parameter names" or "SQL parameters") 4283** can be set using the sqlite3_bind_*() routines defined here. 4284** 4285** ^The first argument to the sqlite3_bind_*() routines is always 4286** a pointer to the [sqlite3_stmt] object returned from 4287** [sqlite3_prepare_v2()] or its variants. 4288** 4289** ^The second argument is the index of the SQL parameter to be set. 4290** ^The leftmost SQL parameter has an index of 1. ^When the same named 4291** SQL parameter is used more than once, second and subsequent 4292** occurrences have the same index as the first occurrence. 4293** ^The index for named parameters can be looked up using the 4294** [sqlite3_bind_parameter_index()] API if desired. ^The index 4295** for "?NNN" parameters is the value of NNN. 4296** ^The NNN value must be between 1 and the [sqlite3_limit()] 4297** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766). 4298** 4299** ^The third argument is the value to bind to the parameter. 4300** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4301** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 4302** is ignored and the end result is the same as sqlite3_bind_null(). 4303** ^If the third parameter to sqlite3_bind_text() is not NULL, then 4304** it should be a pointer to well-formed UTF8 text. 4305** ^If the third parameter to sqlite3_bind_text16() is not NULL, then 4306** it should be a pointer to well-formed UTF16 text. 4307** ^If the third parameter to sqlite3_bind_text64() is not NULL, then 4308** it should be a pointer to a well-formed unicode string that is 4309** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16 4310** otherwise. 4311** 4312** [[byte-order determination rules]] ^The byte-order of 4313** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF) 4314** found in first character, which is removed, or in the absence of a BOM 4315** the byte order is the native byte order of the host 4316** machine for sqlite3_bind_text16() or the byte order specified in 4317** the 6th parameter for sqlite3_bind_text64().)^ 4318** ^If UTF16 input text contains invalid unicode 4319** characters, then SQLite might change those invalid characters 4320** into the unicode replacement character: U+FFFD. 4321** 4322** ^(In those routines that have a fourth argument, its value is the 4323** number of bytes in the parameter. To be clear: the value is the 4324** number of <u>bytes</u> in the value, not the number of characters.)^ 4325** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4326** is negative, then the length of the string is 4327** the number of bytes up to the first zero terminator. 4328** If the fourth parameter to sqlite3_bind_blob() is negative, then 4329** the behavior is undefined. 4330** If a non-negative fourth parameter is provided to sqlite3_bind_text() 4331** or sqlite3_bind_text16() or sqlite3_bind_text64() then 4332** that parameter must be the byte offset 4333** where the NUL terminator would occur assuming the string were NUL 4334** terminated. If any NUL characters occurs at byte offsets less than 4335** the value of the fourth parameter then the resulting string value will 4336** contain embedded NULs. The result of expressions involving strings 4337** with embedded NULs is undefined. 4338** 4339** ^The fifth argument to the BLOB and string binding interfaces 4340** is a destructor used to dispose of the BLOB or 4341** string after SQLite has finished with it. ^The destructor is called 4342** to dispose of the BLOB or string even if the call to the bind API fails, 4343** except the destructor is not called if the third parameter is a NULL 4344** pointer or the fourth parameter is negative. 4345** ^If the fifth argument is 4346** the special value [SQLITE_STATIC], then SQLite assumes that the 4347** information is in static, unmanaged space and does not need to be freed. 4348** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 4349** SQLite makes its own private copy of the data immediately, before 4350** the sqlite3_bind_*() routine returns. 4351** 4352** ^The sixth argument to sqlite3_bind_text64() must be one of 4353** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 4354** to specify the encoding of the text in the third parameter. If 4355** the sixth argument to sqlite3_bind_text64() is not one of the 4356** allowed values shown above, or if the text encoding is different 4357** from the encoding specified by the sixth parameter, then the behavior 4358** is undefined. 4359** 4360** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 4361** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 4362** (just an integer to hold its size) while it is being processed. 4363** Zeroblobs are intended to serve as placeholders for BLOBs whose 4364** content is later written using 4365** [sqlite3_blob_open | incremental BLOB I/O] routines. 4366** ^A negative value for the zeroblob results in a zero-length BLOB. 4367** 4368** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 4369** [prepared statement] S to have an SQL value of NULL, but to also be 4370** associated with the pointer P of type T. ^D is either a NULL pointer or 4371** a pointer to a destructor function for P. ^SQLite will invoke the 4372** destructor D with a single argument of P when it is finished using 4373** P. The T parameter should be a static string, preferably a string 4374** literal. The sqlite3_bind_pointer() routine is part of the 4375** [pointer passing interface] added for SQLite 3.20.0. 4376** 4377** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 4378** for the [prepared statement] or with a prepared statement for which 4379** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 4380** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 4381** routine is passed a [prepared statement] that has been finalized, the 4382** result is undefined and probably harmful. 4383** 4384** ^Bindings are not cleared by the [sqlite3_reset()] routine. 4385** ^Unbound parameters are interpreted as NULL. 4386** 4387** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 4388** [error code] if anything goes wrong. 4389** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 4390** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 4391** [SQLITE_MAX_LENGTH]. 4392** ^[SQLITE_RANGE] is returned if the parameter 4393** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 4394** 4395** See also: [sqlite3_bind_parameter_count()], 4396** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 4397*/ 4398int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 4399int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 4400 void(*)(void*)); 4401int sqlite3_bind_double(sqlite3_stmt*, int, double); 4402int sqlite3_bind_int(sqlite3_stmt*, int, int); 4403int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 4404int sqlite3_bind_null(sqlite3_stmt*, int); 4405int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 4406int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 4407int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 4408 void(*)(void*), unsigned char encoding); 4409int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 4410int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 4411int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 4412int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 4413 4414/* 4415** CAPI3REF: Number Of SQL Parameters 4416** METHOD: sqlite3_stmt 4417** 4418** ^This routine can be used to find the number of [SQL parameters] 4419** in a [prepared statement]. SQL parameters are tokens of the 4420** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4421** placeholders for values that are [sqlite3_bind_blob | bound] 4422** to the parameters at a later time. 4423** 4424** ^(This routine actually returns the index of the largest (rightmost) 4425** parameter. For all forms except ?NNN, this will correspond to the 4426** number of unique parameters. If parameters of the ?NNN form are used, 4427** there may be gaps in the list.)^ 4428** 4429** See also: [sqlite3_bind_blob|sqlite3_bind()], 4430** [sqlite3_bind_parameter_name()], and 4431** [sqlite3_bind_parameter_index()]. 4432*/ 4433int sqlite3_bind_parameter_count(sqlite3_stmt*); 4434 4435/* 4436** CAPI3REF: Name Of A Host Parameter 4437** METHOD: sqlite3_stmt 4438** 4439** ^The sqlite3_bind_parameter_name(P,N) interface returns 4440** the name of the N-th [SQL parameter] in the [prepared statement] P. 4441** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4442** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4443** respectively. 4444** In other words, the initial ":" or "$" or "@" or "?" 4445** is included as part of the name.)^ 4446** ^Parameters of the form "?" without a following integer have no name 4447** and are referred to as "nameless" or "anonymous parameters". 4448** 4449** ^The first host parameter has an index of 1, not 0. 4450** 4451** ^If the value N is out of range or if the N-th parameter is 4452** nameless, then NULL is returned. ^The returned string is 4453** always in UTF-8 encoding even if the named parameter was 4454** originally specified as UTF-16 in [sqlite3_prepare16()], 4455** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4456** 4457** See also: [sqlite3_bind_blob|sqlite3_bind()], 4458** [sqlite3_bind_parameter_count()], and 4459** [sqlite3_bind_parameter_index()]. 4460*/ 4461const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4462 4463/* 4464** CAPI3REF: Index Of A Parameter With A Given Name 4465** METHOD: sqlite3_stmt 4466** 4467** ^Return the index of an SQL parameter given its name. ^The 4468** index value returned is suitable for use as the second 4469** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4470** is returned if no matching parameter is found. ^The parameter 4471** name must be given in UTF-8 even if the original statement 4472** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4473** [sqlite3_prepare16_v3()]. 4474** 4475** See also: [sqlite3_bind_blob|sqlite3_bind()], 4476** [sqlite3_bind_parameter_count()], and 4477** [sqlite3_bind_parameter_name()]. 4478*/ 4479int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4480 4481/* 4482** CAPI3REF: Reset All Bindings On A Prepared Statement 4483** METHOD: sqlite3_stmt 4484** 4485** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4486** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4487** ^Use this routine to reset all host parameters to NULL. 4488*/ 4489int sqlite3_clear_bindings(sqlite3_stmt*); 4490 4491/* 4492** CAPI3REF: Number Of Columns In A Result Set 4493** METHOD: sqlite3_stmt 4494** 4495** ^Return the number of columns in the result set returned by the 4496** [prepared statement]. ^If this routine returns 0, that means the 4497** [prepared statement] returns no data (for example an [UPDATE]). 4498** ^However, just because this routine returns a positive number does not 4499** mean that one or more rows of data will be returned. ^A SELECT statement 4500** will always have a positive sqlite3_column_count() but depending on the 4501** WHERE clause constraints and the table content, it might return no rows. 4502** 4503** See also: [sqlite3_data_count()] 4504*/ 4505int sqlite3_column_count(sqlite3_stmt *pStmt); 4506 4507/* 4508** CAPI3REF: Column Names In A Result Set 4509** METHOD: sqlite3_stmt 4510** 4511** ^These routines return the name assigned to a particular column 4512** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4513** interface returns a pointer to a zero-terminated UTF-8 string 4514** and sqlite3_column_name16() returns a pointer to a zero-terminated 4515** UTF-16 string. ^The first parameter is the [prepared statement] 4516** that implements the [SELECT] statement. ^The second parameter is the 4517** column number. ^The leftmost column is number 0. 4518** 4519** ^The returned string pointer is valid until either the [prepared statement] 4520** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4521** reprepared by the first call to [sqlite3_step()] for a particular run 4522** or until the next call to 4523** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4524** 4525** ^If sqlite3_malloc() fails during the processing of either routine 4526** (for example during a conversion from UTF-8 to UTF-16) then a 4527** NULL pointer is returned. 4528** 4529** ^The name of a result column is the value of the "AS" clause for 4530** that column, if there is an AS clause. If there is no AS clause 4531** then the name of the column is unspecified and may change from 4532** one release of SQLite to the next. 4533*/ 4534const char *sqlite3_column_name(sqlite3_stmt*, int N); 4535const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4536 4537/* 4538** CAPI3REF: Source Of Data In A Query Result 4539** METHOD: sqlite3_stmt 4540** 4541** ^These routines provide a means to determine the database, table, and 4542** table column that is the origin of a particular result column in 4543** [SELECT] statement. 4544** ^The name of the database or table or column can be returned as 4545** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4546** the database name, the _table_ routines return the table name, and 4547** the origin_ routines return the column name. 4548** ^The returned string is valid until the [prepared statement] is destroyed 4549** using [sqlite3_finalize()] or until the statement is automatically 4550** reprepared by the first call to [sqlite3_step()] for a particular run 4551** or until the same information is requested 4552** again in a different encoding. 4553** 4554** ^The names returned are the original un-aliased names of the 4555** database, table, and column. 4556** 4557** ^The first argument to these interfaces is a [prepared statement]. 4558** ^These functions return information about the Nth result column returned by 4559** the statement, where N is the second function argument. 4560** ^The left-most column is column 0 for these routines. 4561** 4562** ^If the Nth column returned by the statement is an expression or 4563** subquery and is not a column value, then all of these functions return 4564** NULL. ^These routines might also return NULL if a memory allocation error 4565** occurs. ^Otherwise, they return the name of the attached database, table, 4566** or column that query result column was extracted from. 4567** 4568** ^As with all other SQLite APIs, those whose names end with "16" return 4569** UTF-16 encoded strings and the other functions return UTF-8. 4570** 4571** ^These APIs are only available if the library was compiled with the 4572** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4573** 4574** If two or more threads call one or more 4575** [sqlite3_column_database_name | column metadata interfaces] 4576** for the same [prepared statement] and result column 4577** at the same time then the results are undefined. 4578*/ 4579const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4580const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4581const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4582const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4583const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4584const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4585 4586/* 4587** CAPI3REF: Declared Datatype Of A Query Result 4588** METHOD: sqlite3_stmt 4589** 4590** ^(The first parameter is a [prepared statement]. 4591** If this statement is a [SELECT] statement and the Nth column of the 4592** returned result set of that [SELECT] is a table column (not an 4593** expression or subquery) then the declared type of the table 4594** column is returned.)^ ^If the Nth column of the result set is an 4595** expression or subquery, then a NULL pointer is returned. 4596** ^The returned string is always UTF-8 encoded. 4597** 4598** ^(For example, given the database schema: 4599** 4600** CREATE TABLE t1(c1 VARIANT); 4601** 4602** and the following statement to be compiled: 4603** 4604** SELECT c1 + 1, c1 FROM t1; 4605** 4606** this routine would return the string "VARIANT" for the second result 4607** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4608** 4609** ^SQLite uses dynamic run-time typing. ^So just because a column 4610** is declared to contain a particular type does not mean that the 4611** data stored in that column is of the declared type. SQLite is 4612** strongly typed, but the typing is dynamic not static. ^Type 4613** is associated with individual values, not with the containers 4614** used to hold those values. 4615*/ 4616const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4617const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4618 4619/* 4620** CAPI3REF: Evaluate An SQL Statement 4621** METHOD: sqlite3_stmt 4622** 4623** After a [prepared statement] has been prepared using any of 4624** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4625** or [sqlite3_prepare16_v3()] or one of the legacy 4626** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4627** must be called one or more times to evaluate the statement. 4628** 4629** The details of the behavior of the sqlite3_step() interface depend 4630** on whether the statement was prepared using the newer "vX" interfaces 4631** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4632** [sqlite3_prepare16_v2()] or the older legacy 4633** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4634** new "vX" interface is recommended for new applications but the legacy 4635** interface will continue to be supported. 4636** 4637** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4638** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4639** ^With the "v2" interface, any of the other [result codes] or 4640** [extended result codes] might be returned as well. 4641** 4642** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4643** database locks it needs to do its job. ^If the statement is a [COMMIT] 4644** or occurs outside of an explicit transaction, then you can retry the 4645** statement. If the statement is not a [COMMIT] and occurs within an 4646** explicit transaction then you should rollback the transaction before 4647** continuing. 4648** 4649** ^[SQLITE_DONE] means that the statement has finished executing 4650** successfully. sqlite3_step() should not be called again on this virtual 4651** machine without first calling [sqlite3_reset()] to reset the virtual 4652** machine back to its initial state. 4653** 4654** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4655** is returned each time a new row of data is ready for processing by the 4656** caller. The values may be accessed using the [column access functions]. 4657** sqlite3_step() is called again to retrieve the next row of data. 4658** 4659** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4660** violation) has occurred. sqlite3_step() should not be called again on 4661** the VM. More information may be found by calling [sqlite3_errmsg()]. 4662** ^With the legacy interface, a more specific error code (for example, 4663** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4664** can be obtained by calling [sqlite3_reset()] on the 4665** [prepared statement]. ^In the "v2" interface, 4666** the more specific error code is returned directly by sqlite3_step(). 4667** 4668** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4669** Perhaps it was called on a [prepared statement] that has 4670** already been [sqlite3_finalize | finalized] or on one that had 4671** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4672** be the case that the same database connection is being used by two or 4673** more threads at the same moment in time. 4674** 4675** For all versions of SQLite up to and including 3.6.23.1, a call to 4676** [sqlite3_reset()] was required after sqlite3_step() returned anything 4677** other than [SQLITE_ROW] before any subsequent invocation of 4678** sqlite3_step(). Failure to reset the prepared statement using 4679** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4680** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4681** sqlite3_step() began 4682** calling [sqlite3_reset()] automatically in this circumstance rather 4683** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4684** break because any application that ever receives an SQLITE_MISUSE error 4685** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4686** can be used to restore the legacy behavior. 4687** 4688** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4689** API always returns a generic error code, [SQLITE_ERROR], following any 4690** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4691** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4692** specific [error codes] that better describes the error. 4693** We admit that this is a goofy design. The problem has been fixed 4694** with the "v2" interface. If you prepare all of your SQL statements 4695** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4696** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4697** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4698** then the more specific [error codes] are returned directly 4699** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4700*/ 4701int sqlite3_step(sqlite3_stmt*); 4702 4703/* 4704** CAPI3REF: Number of columns in a result set 4705** METHOD: sqlite3_stmt 4706** 4707** ^The sqlite3_data_count(P) interface returns the number of columns in the 4708** current row of the result set of [prepared statement] P. 4709** ^If prepared statement P does not have results ready to return 4710** (via calls to the [sqlite3_column_int | sqlite3_column()] family of 4711** interfaces) then sqlite3_data_count(P) returns 0. 4712** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4713** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4714** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4715** will return non-zero if previous call to [sqlite3_step](P) returned 4716** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4717** where it always returns zero since each step of that multi-step 4718** pragma returns 0 columns of data. 4719** 4720** See also: [sqlite3_column_count()] 4721*/ 4722int sqlite3_data_count(sqlite3_stmt *pStmt); 4723 4724/* 4725** CAPI3REF: Fundamental Datatypes 4726** KEYWORDS: SQLITE_TEXT 4727** 4728** ^(Every value in SQLite has one of five fundamental datatypes: 4729** 4730** <ul> 4731** <li> 64-bit signed integer 4732** <li> 64-bit IEEE floating point number 4733** <li> string 4734** <li> BLOB 4735** <li> NULL 4736** </ul>)^ 4737** 4738** These constants are codes for each of those types. 4739** 4740** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4741** for a completely different meaning. Software that links against both 4742** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4743** SQLITE_TEXT. 4744*/ 4745#define SQLITE_INTEGER 1 4746#define SQLITE_FLOAT 2 4747#define SQLITE_BLOB 4 4748#define SQLITE_NULL 5 4749#ifdef SQLITE_TEXT 4750# undef SQLITE_TEXT 4751#else 4752# define SQLITE_TEXT 3 4753#endif 4754#define SQLITE3_TEXT 3 4755 4756/* 4757** CAPI3REF: Result Values From A Query 4758** KEYWORDS: {column access functions} 4759** METHOD: sqlite3_stmt 4760** 4761** <b>Summary:</b> 4762** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4763** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4764** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4765** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4766** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4767** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4768** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4769** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4770** [sqlite3_value|unprotected sqlite3_value] object. 4771** <tr><td> <td> <td> 4772** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4773** or a UTF-8 TEXT result in bytes 4774** <tr><td><b>sqlite3_column_bytes16 </b> 4775** <td>→ <td>Size of UTF-16 4776** TEXT in bytes 4777** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4778** datatype of the result 4779** </table></blockquote> 4780** 4781** <b>Details:</b> 4782** 4783** ^These routines return information about a single column of the current 4784** result row of a query. ^In every case the first argument is a pointer 4785** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4786** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4787** and the second argument is the index of the column for which information 4788** should be returned. ^The leftmost column of the result set has the index 0. 4789** ^The number of columns in the result can be determined using 4790** [sqlite3_column_count()]. 4791** 4792** If the SQL statement does not currently point to a valid row, or if the 4793** column index is out of range, the result is undefined. 4794** These routines may only be called when the most recent call to 4795** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4796** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4797** If any of these routines are called after [sqlite3_reset()] or 4798** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4799** something other than [SQLITE_ROW], the results are undefined. 4800** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4801** are called from a different thread while any of these routines 4802** are pending, then the results are undefined. 4803** 4804** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4805** each return the value of a result column in a specific data format. If 4806** the result column is not initially in the requested format (for example, 4807** if the query returns an integer but the sqlite3_column_text() interface 4808** is used to extract the value) then an automatic type conversion is performed. 4809** 4810** ^The sqlite3_column_type() routine returns the 4811** [SQLITE_INTEGER | datatype code] for the initial data type 4812** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4813** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4814** The return value of sqlite3_column_type() can be used to decide which 4815** of the first six interface should be used to extract the column value. 4816** The value returned by sqlite3_column_type() is only meaningful if no 4817** automatic type conversions have occurred for the value in question. 4818** After a type conversion, the result of calling sqlite3_column_type() 4819** is undefined, though harmless. Future 4820** versions of SQLite may change the behavior of sqlite3_column_type() 4821** following a type conversion. 4822** 4823** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4824** or sqlite3_column_bytes16() interfaces can be used to determine the size 4825** of that BLOB or string. 4826** 4827** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4828** routine returns the number of bytes in that BLOB or string. 4829** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4830** the string to UTF-8 and then returns the number of bytes. 4831** ^If the result is a numeric value then sqlite3_column_bytes() uses 4832** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4833** the number of bytes in that string. 4834** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4835** 4836** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4837** routine returns the number of bytes in that BLOB or string. 4838** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4839** the string to UTF-16 and then returns the number of bytes. 4840** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4841** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4842** the number of bytes in that string. 4843** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4844** 4845** ^The values returned by [sqlite3_column_bytes()] and 4846** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4847** of the string. ^For clarity: the values returned by 4848** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4849** bytes in the string, not the number of characters. 4850** 4851** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4852** even empty strings, are always zero-terminated. ^The return 4853** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4854** 4855** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4856** [unprotected sqlite3_value] object. In a multithreaded environment, 4857** an unprotected sqlite3_value object may only be used safely with 4858** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4859** If the [unprotected sqlite3_value] object returned by 4860** [sqlite3_column_value()] is used in any other way, including calls 4861** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4862** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4863** Hence, the sqlite3_column_value() interface 4864** is normally only useful within the implementation of 4865** [application-defined SQL functions] or [virtual tables], not within 4866** top-level application code. 4867** 4868** The these routines may attempt to convert the datatype of the result. 4869** ^For example, if the internal representation is FLOAT and a text result 4870** is requested, [sqlite3_snprintf()] is used internally to perform the 4871** conversion automatically. ^(The following table details the conversions 4872** that are applied: 4873** 4874** <blockquote> 4875** <table border="1"> 4876** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4877** 4878** <tr><td> NULL <td> INTEGER <td> Result is 0 4879** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4880** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4881** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4882** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4883** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4884** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4885** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4886** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4887** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4888** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4889** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4890** <tr><td> TEXT <td> BLOB <td> No change 4891** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4892** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4893** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4894** </table> 4895** </blockquote>)^ 4896** 4897** Note that when type conversions occur, pointers returned by prior 4898** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4899** sqlite3_column_text16() may be invalidated. 4900** Type conversions and pointer invalidations might occur 4901** in the following cases: 4902** 4903** <ul> 4904** <li> The initial content is a BLOB and sqlite3_column_text() or 4905** sqlite3_column_text16() is called. A zero-terminator might 4906** need to be added to the string.</li> 4907** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4908** sqlite3_column_text16() is called. The content must be converted 4909** to UTF-16.</li> 4910** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4911** sqlite3_column_text() is called. The content must be converted 4912** to UTF-8.</li> 4913** </ul> 4914** 4915** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4916** not invalidate a prior pointer, though of course the content of the buffer 4917** that the prior pointer references will have been modified. Other kinds 4918** of conversion are done in place when it is possible, but sometimes they 4919** are not possible and in those cases prior pointers are invalidated. 4920** 4921** The safest policy is to invoke these routines 4922** in one of the following ways: 4923** 4924** <ul> 4925** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4926** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4927** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4928** </ul> 4929** 4930** In other words, you should call sqlite3_column_text(), 4931** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4932** into the desired format, then invoke sqlite3_column_bytes() or 4933** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4934** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4935** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4936** with calls to sqlite3_column_bytes(). 4937** 4938** ^The pointers returned are valid until a type conversion occurs as 4939** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4940** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4941** and BLOBs is freed automatically. Do not pass the pointers returned 4942** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4943** [sqlite3_free()]. 4944** 4945** As long as the input parameters are correct, these routines will only 4946** fail if an out-of-memory error occurs during a format conversion. 4947** Only the following subset of interfaces are subject to out-of-memory 4948** errors: 4949** 4950** <ul> 4951** <li> sqlite3_column_blob() 4952** <li> sqlite3_column_text() 4953** <li> sqlite3_column_text16() 4954** <li> sqlite3_column_bytes() 4955** <li> sqlite3_column_bytes16() 4956** </ul> 4957** 4958** If an out-of-memory error occurs, then the return value from these 4959** routines is the same as if the column had contained an SQL NULL value. 4960** Valid SQL NULL returns can be distinguished from out-of-memory errors 4961** by invoking the [sqlite3_errcode()] immediately after the suspect 4962** return value is obtained and before any 4963** other SQLite interface is called on the same [database connection]. 4964*/ 4965const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4966double sqlite3_column_double(sqlite3_stmt*, int iCol); 4967int sqlite3_column_int(sqlite3_stmt*, int iCol); 4968sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4969const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4970const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4971sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4972int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4973int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4974int sqlite3_column_type(sqlite3_stmt*, int iCol); 4975 4976/* 4977** CAPI3REF: Destroy A Prepared Statement Object 4978** DESTRUCTOR: sqlite3_stmt 4979** 4980** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4981** ^If the most recent evaluation of the statement encountered no errors 4982** or if the statement is never been evaluated, then sqlite3_finalize() returns 4983** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4984** sqlite3_finalize(S) returns the appropriate [error code] or 4985** [extended error code]. 4986** 4987** ^The sqlite3_finalize(S) routine can be called at any point during 4988** the life cycle of [prepared statement] S: 4989** before statement S is ever evaluated, after 4990** one or more calls to [sqlite3_reset()], or after any call 4991** to [sqlite3_step()] regardless of whether or not the statement has 4992** completed execution. 4993** 4994** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4995** 4996** The application must finalize every [prepared statement] in order to avoid 4997** resource leaks. It is a grievous error for the application to try to use 4998** a prepared statement after it has been finalized. Any use of a prepared 4999** statement after it has been finalized can result in undefined and 5000** undesirable behavior such as segfaults and heap corruption. 5001*/ 5002int sqlite3_finalize(sqlite3_stmt *pStmt); 5003 5004/* 5005** CAPI3REF: Reset A Prepared Statement Object 5006** METHOD: sqlite3_stmt 5007** 5008** The sqlite3_reset() function is called to reset a [prepared statement] 5009** object back to its initial state, ready to be re-executed. 5010** ^Any SQL statement variables that had values bound to them using 5011** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 5012** Use [sqlite3_clear_bindings()] to reset the bindings. 5013** 5014** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 5015** back to the beginning of its program. 5016** 5017** ^If the most recent call to [sqlite3_step(S)] for the 5018** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 5019** or if [sqlite3_step(S)] has never before been called on S, 5020** then [sqlite3_reset(S)] returns [SQLITE_OK]. 5021** 5022** ^If the most recent call to [sqlite3_step(S)] for the 5023** [prepared statement] S indicated an error, then 5024** [sqlite3_reset(S)] returns an appropriate [error code]. 5025** 5026** ^The [sqlite3_reset(S)] interface does not change the values 5027** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 5028*/ 5029int sqlite3_reset(sqlite3_stmt *pStmt); 5030 5031/* 5032** CAPI3REF: Create Or Redefine SQL Functions 5033** KEYWORDS: {function creation routines} 5034** METHOD: sqlite3 5035** 5036** ^These functions (collectively known as "function creation routines") 5037** are used to add SQL functions or aggregates or to redefine the behavior 5038** of existing SQL functions or aggregates. The only differences between 5039** the three "sqlite3_create_function*" routines are the text encoding 5040** expected for the second parameter (the name of the function being 5041** created) and the presence or absence of a destructor callback for 5042** the application data pointer. Function sqlite3_create_window_function() 5043** is similar, but allows the user to supply the extra callback functions 5044** needed by [aggregate window functions]. 5045** 5046** ^The first parameter is the [database connection] to which the SQL 5047** function is to be added. ^If an application uses more than one database 5048** connection then application-defined SQL functions must be added 5049** to each database connection separately. 5050** 5051** ^The second parameter is the name of the SQL function to be created or 5052** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 5053** representation, exclusive of the zero-terminator. ^Note that the name 5054** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 5055** ^Any attempt to create a function with a longer name 5056** will result in [SQLITE_MISUSE] being returned. 5057** 5058** ^The third parameter (nArg) 5059** is the number of arguments that the SQL function or 5060** aggregate takes. ^If this parameter is -1, then the SQL function or 5061** aggregate may take any number of arguments between 0 and the limit 5062** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 5063** parameter is less than -1 or greater than 127 then the behavior is 5064** undefined. 5065** 5066** ^The fourth parameter, eTextRep, specifies what 5067** [SQLITE_UTF8 | text encoding] this SQL function prefers for 5068** its parameters. The application should set this parameter to 5069** [SQLITE_UTF16LE] if the function implementation invokes 5070** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 5071** implementation invokes [sqlite3_value_text16be()] on an input, or 5072** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 5073** otherwise. ^The same SQL function may be registered multiple times using 5074** different preferred text encodings, with different implementations for 5075** each encoding. 5076** ^When multiple implementations of the same function are available, SQLite 5077** will pick the one that involves the least amount of data conversion. 5078** 5079** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 5080** to signal that the function will always return the same result given 5081** the same inputs within a single SQL statement. Most SQL functions are 5082** deterministic. The built-in [random()] SQL function is an example of a 5083** function that is not deterministic. The SQLite query planner is able to 5084** perform additional optimizations on deterministic functions, so use 5085** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 5086** 5087** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY] 5088** flag, which if present prevents the function from being invoked from 5089** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions, 5090** index expressions, or the WHERE clause of partial indexes. 5091** 5092** <span style="background-color:#ffff90;"> 5093** For best security, the [SQLITE_DIRECTONLY] flag is recommended for 5094** all application-defined SQL functions that do not need to be 5095** used inside of triggers, view, CHECK constraints, or other elements of 5096** the database schema. This flags is especially recommended for SQL 5097** functions that have side effects or reveal internal application state. 5098** Without this flag, an attacker might be able to modify the schema of 5099** a database file to include invocations of the function with parameters 5100** chosen by the attacker, which the application will then execute when 5101** the database file is opened and read. 5102** </span> 5103** 5104** ^(The fifth parameter is an arbitrary pointer. The implementation of the 5105** function can gain access to this pointer using [sqlite3_user_data()].)^ 5106** 5107** ^The sixth, seventh and eighth parameters passed to the three 5108** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are 5109** pointers to C-language functions that implement the SQL function or 5110** aggregate. ^A scalar SQL function requires an implementation of the xFunc 5111** callback only; NULL pointers must be passed as the xStep and xFinal 5112** parameters. ^An aggregate SQL function requires an implementation of xStep 5113** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 5114** SQL function or aggregate, pass NULL pointers for all three function 5115** callbacks. 5116** 5117** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue 5118** and xInverse) passed to sqlite3_create_window_function are pointers to 5119** C-language callbacks that implement the new function. xStep and xFinal 5120** must both be non-NULL. xValue and xInverse may either both be NULL, in 5121** which case a regular aggregate function is created, or must both be 5122** non-NULL, in which case the new function may be used as either an aggregate 5123** or aggregate window function. More details regarding the implementation 5124** of aggregate window functions are 5125** [user-defined window functions|available here]. 5126** 5127** ^(If the final parameter to sqlite3_create_function_v2() or 5128** sqlite3_create_window_function() is not NULL, then it is destructor for 5129** the application data pointer. The destructor is invoked when the function 5130** is deleted, either by being overloaded or when the database connection 5131** closes.)^ ^The destructor is also invoked if the call to 5132** sqlite3_create_function_v2() fails. ^When the destructor callback is 5133** invoked, it is passed a single argument which is a copy of the application 5134** data pointer which was the fifth parameter to sqlite3_create_function_v2(). 5135** 5136** ^It is permitted to register multiple implementations of the same 5137** functions with the same name but with either differing numbers of 5138** arguments or differing preferred text encodings. ^SQLite will use 5139** the implementation that most closely matches the way in which the 5140** SQL function is used. ^A function implementation with a non-negative 5141** nArg parameter is a better match than a function implementation with 5142** a negative nArg. ^A function where the preferred text encoding 5143** matches the database encoding is a better 5144** match than a function where the encoding is different. 5145** ^A function where the encoding difference is between UTF16le and UTF16be 5146** is a closer match than a function where the encoding difference is 5147** between UTF8 and UTF16. 5148** 5149** ^Built-in functions may be overloaded by new application-defined functions. 5150** 5151** ^An application-defined function is permitted to call other 5152** SQLite interfaces. However, such calls must not 5153** close the database connection nor finalize or reset the prepared 5154** statement in which the function is running. 5155*/ 5156int sqlite3_create_function( 5157 sqlite3 *db, 5158 const char *zFunctionName, 5159 int nArg, 5160 int eTextRep, 5161 void *pApp, 5162 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5163 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5164 void (*xFinal)(sqlite3_context*) 5165); 5166int sqlite3_create_function16( 5167 sqlite3 *db, 5168 const void *zFunctionName, 5169 int nArg, 5170 int eTextRep, 5171 void *pApp, 5172 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5173 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5174 void (*xFinal)(sqlite3_context*) 5175); 5176int sqlite3_create_function_v2( 5177 sqlite3 *db, 5178 const char *zFunctionName, 5179 int nArg, 5180 int eTextRep, 5181 void *pApp, 5182 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5183 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5184 void (*xFinal)(sqlite3_context*), 5185 void(*xDestroy)(void*) 5186); 5187int sqlite3_create_window_function( 5188 sqlite3 *db, 5189 const char *zFunctionName, 5190 int nArg, 5191 int eTextRep, 5192 void *pApp, 5193 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5194 void (*xFinal)(sqlite3_context*), 5195 void (*xValue)(sqlite3_context*), 5196 void (*xInverse)(sqlite3_context*,int,sqlite3_value**), 5197 void(*xDestroy)(void*) 5198); 5199 5200/* 5201** CAPI3REF: Text Encodings 5202** 5203** These constant define integer codes that represent the various 5204** text encodings supported by SQLite. 5205*/ 5206#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 5207#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 5208#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 5209#define SQLITE_UTF16 4 /* Use native byte order */ 5210#define SQLITE_ANY 5 /* Deprecated */ 5211#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 5212 5213/* 5214** CAPI3REF: Function Flags 5215** 5216** These constants may be ORed together with the 5217** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 5218** to [sqlite3_create_function()], [sqlite3_create_function16()], or 5219** [sqlite3_create_function_v2()]. 5220** 5221** <dl> 5222** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd> 5223** The SQLITE_DETERMINISTIC flag means that the new function always gives 5224** the same output when the input parameters are the same. 5225** The [abs|abs() function] is deterministic, for example, but 5226** [randomblob|randomblob()] is not. Functions must 5227** be deterministic in order to be used in certain contexts such as 5228** with the WHERE clause of [partial indexes] or in [generated columns]. 5229** SQLite might also optimize deterministic functions by factoring them 5230** out of inner loops. 5231** </dd> 5232** 5233** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd> 5234** The SQLITE_DIRECTONLY flag means that the function may only be invoked 5235** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in 5236** schema structures such as [CHECK constraints], [DEFAULT clauses], 5237** [expression indexes], [partial indexes], or [generated columns]. 5238** The SQLITE_DIRECTONLY flags is a security feature which is recommended 5239** for all [application-defined SQL functions], and especially for functions 5240** that have side-effects or that could potentially leak sensitive 5241** information. 5242** </dd> 5243** 5244** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd> 5245** The SQLITE_INNOCUOUS flag means that the function is unlikely 5246** to cause problems even if misused. An innocuous function should have 5247** no side effects and should not depend on any values other than its 5248** input parameters. The [abs|abs() function] is an example of an 5249** innocuous function. 5250** The [load_extension() SQL function] is not innocuous because of its 5251** side effects. 5252** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not 5253** exactly the same. The [random|random() function] is an example of a 5254** function that is innocuous but not deterministic. 5255** <p>Some heightened security settings 5256** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF]) 5257** disable the use of SQL functions inside views and triggers and in 5258** schema structures such as [CHECK constraints], [DEFAULT clauses], 5259** [expression indexes], [partial indexes], and [generated columns] unless 5260** the function is tagged with SQLITE_INNOCUOUS. Most built-in functions 5261** are innocuous. Developers are advised to avoid using the 5262** SQLITE_INNOCUOUS flag for application-defined functions unless the 5263** function has been carefully audited and found to be free of potentially 5264** security-adverse side-effects and information-leaks. 5265** </dd> 5266** 5267** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd> 5268** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call 5269** [sqlite3_value_subtype()] to inspect the sub-types of its arguments. 5270** Specifying this flag makes no difference for scalar or aggregate user 5271** functions. However, if it is not specified for a user-defined window 5272** function, then any sub-types belonging to arguments passed to the window 5273** function may be discarded before the window function is called (i.e. 5274** sqlite3_value_subtype() will always return 0). 5275** </dd> 5276** </dl> 5277*/ 5278#define SQLITE_DETERMINISTIC 0x000000800 5279#define SQLITE_DIRECTONLY 0x000080000 5280#define SQLITE_SUBTYPE 0x000100000 5281#define SQLITE_INNOCUOUS 0x000200000 5282 5283/* 5284** CAPI3REF: Deprecated Functions 5285** DEPRECATED 5286** 5287** These functions are [deprecated]. In order to maintain 5288** backwards compatibility with older code, these functions continue 5289** to be supported. However, new applications should avoid 5290** the use of these functions. To encourage programmers to avoid 5291** these functions, we will not explain what they do. 5292*/ 5293#ifndef SQLITE_OMIT_DEPRECATED 5294SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 5295SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 5296SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 5297SQLITE_DEPRECATED int sqlite3_global_recover(void); 5298SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 5299SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 5300 void*,sqlite3_int64); 5301#endif 5302 5303/* 5304** CAPI3REF: Obtaining SQL Values 5305** METHOD: sqlite3_value 5306** 5307** <b>Summary:</b> 5308** <blockquote><table border=0 cellpadding=0 cellspacing=0> 5309** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 5310** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 5311** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 5312** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 5313** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 5314** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 5315** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 5316** the native byteorder 5317** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 5318** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 5319** <tr><td> <td> <td> 5320** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 5321** or a UTF-8 TEXT in bytes 5322** <tr><td><b>sqlite3_value_bytes16 </b> 5323** <td>→ <td>Size of UTF-16 5324** TEXT in bytes 5325** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 5326** datatype of the value 5327** <tr><td><b>sqlite3_value_numeric_type </b> 5328** <td>→ <td>Best numeric datatype of the value 5329** <tr><td><b>sqlite3_value_nochange </b> 5330** <td>→ <td>True if the column is unchanged in an UPDATE 5331** against a virtual table. 5332** <tr><td><b>sqlite3_value_frombind </b> 5333** <td>→ <td>True if value originated from a [bound parameter] 5334** </table></blockquote> 5335** 5336** <b>Details:</b> 5337** 5338** These routines extract type, size, and content information from 5339** [protected sqlite3_value] objects. Protected sqlite3_value objects 5340** are used to pass parameter information into the functions that 5341** implement [application-defined SQL functions] and [virtual tables]. 5342** 5343** These routines work only with [protected sqlite3_value] objects. 5344** Any attempt to use these routines on an [unprotected sqlite3_value] 5345** is not threadsafe. 5346** 5347** ^These routines work just like the corresponding [column access functions] 5348** except that these routines take a single [protected sqlite3_value] object 5349** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 5350** 5351** ^The sqlite3_value_text16() interface extracts a UTF-16 string 5352** in the native byte-order of the host machine. ^The 5353** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 5354** extract UTF-16 strings as big-endian and little-endian respectively. 5355** 5356** ^If [sqlite3_value] object V was initialized 5357** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 5358** and if X and Y are strings that compare equal according to strcmp(X,Y), 5359** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 5360** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 5361** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5362** 5363** ^(The sqlite3_value_type(V) interface returns the 5364** [SQLITE_INTEGER | datatype code] for the initial datatype of the 5365** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 5366** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 5367** Other interfaces might change the datatype for an sqlite3_value object. 5368** For example, if the datatype is initially SQLITE_INTEGER and 5369** sqlite3_value_text(V) is called to extract a text value for that 5370** integer, then subsequent calls to sqlite3_value_type(V) might return 5371** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 5372** occurs is undefined and may change from one release of SQLite to the next. 5373** 5374** ^(The sqlite3_value_numeric_type() interface attempts to apply 5375** numeric affinity to the value. This means that an attempt is 5376** made to convert the value to an integer or floating point. If 5377** such a conversion is possible without loss of information (in other 5378** words, if the value is a string that looks like a number) 5379** then the conversion is performed. Otherwise no conversion occurs. 5380** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 5381** 5382** ^Within the [xUpdate] method of a [virtual table], the 5383** sqlite3_value_nochange(X) interface returns true if and only if 5384** the column corresponding to X is unchanged by the UPDATE operation 5385** that the xUpdate method call was invoked to implement and if 5386** and the prior [xColumn] method call that was invoked to extracted 5387** the value for that column returned without setting a result (probably 5388** because it queried [sqlite3_vtab_nochange()] and found that the column 5389** was unchanging). ^Within an [xUpdate] method, any value for which 5390** sqlite3_value_nochange(X) is true will in all other respects appear 5391** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 5392** than within an [xUpdate] method call for an UPDATE statement, then 5393** the return value is arbitrary and meaningless. 5394** 5395** ^The sqlite3_value_frombind(X) interface returns non-zero if the 5396** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()] 5397** interfaces. ^If X comes from an SQL literal value, or a table column, 5398** or an expression, then sqlite3_value_frombind(X) returns zero. 5399** 5400** Please pay particular attention to the fact that the pointer returned 5401** from [sqlite3_value_blob()], [sqlite3_value_text()], or 5402** [sqlite3_value_text16()] can be invalidated by a subsequent call to 5403** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 5404** or [sqlite3_value_text16()]. 5405** 5406** These routines must be called from the same thread as 5407** the SQL function that supplied the [sqlite3_value*] parameters. 5408** 5409** As long as the input parameter is correct, these routines can only 5410** fail if an out-of-memory error occurs during a format conversion. 5411** Only the following subset of interfaces are subject to out-of-memory 5412** errors: 5413** 5414** <ul> 5415** <li> sqlite3_value_blob() 5416** <li> sqlite3_value_text() 5417** <li> sqlite3_value_text16() 5418** <li> sqlite3_value_text16le() 5419** <li> sqlite3_value_text16be() 5420** <li> sqlite3_value_bytes() 5421** <li> sqlite3_value_bytes16() 5422** </ul> 5423** 5424** If an out-of-memory error occurs, then the return value from these 5425** routines is the same as if the column had contained an SQL NULL value. 5426** Valid SQL NULL returns can be distinguished from out-of-memory errors 5427** by invoking the [sqlite3_errcode()] immediately after the suspect 5428** return value is obtained and before any 5429** other SQLite interface is called on the same [database connection]. 5430*/ 5431const void *sqlite3_value_blob(sqlite3_value*); 5432double sqlite3_value_double(sqlite3_value*); 5433int sqlite3_value_int(sqlite3_value*); 5434sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 5435void *sqlite3_value_pointer(sqlite3_value*, const char*); 5436const unsigned char *sqlite3_value_text(sqlite3_value*); 5437const void *sqlite3_value_text16(sqlite3_value*); 5438const void *sqlite3_value_text16le(sqlite3_value*); 5439const void *sqlite3_value_text16be(sqlite3_value*); 5440int sqlite3_value_bytes(sqlite3_value*); 5441int sqlite3_value_bytes16(sqlite3_value*); 5442int sqlite3_value_type(sqlite3_value*); 5443int sqlite3_value_numeric_type(sqlite3_value*); 5444int sqlite3_value_nochange(sqlite3_value*); 5445int sqlite3_value_frombind(sqlite3_value*); 5446 5447/* 5448** CAPI3REF: Finding The Subtype Of SQL Values 5449** METHOD: sqlite3_value 5450** 5451** The sqlite3_value_subtype(V) function returns the subtype for 5452** an [application-defined SQL function] argument V. The subtype 5453** information can be used to pass a limited amount of context from 5454** one SQL function to another. Use the [sqlite3_result_subtype()] 5455** routine to set the subtype for the return value of an SQL function. 5456*/ 5457unsigned int sqlite3_value_subtype(sqlite3_value*); 5458 5459/* 5460** CAPI3REF: Copy And Free SQL Values 5461** METHOD: sqlite3_value 5462** 5463** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 5464** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 5465** is a [protected sqlite3_value] object even if the input is not. 5466** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 5467** memory allocation fails. 5468** 5469** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 5470** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 5471** then sqlite3_value_free(V) is a harmless no-op. 5472*/ 5473sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 5474void sqlite3_value_free(sqlite3_value*); 5475 5476/* 5477** CAPI3REF: Obtain Aggregate Function Context 5478** METHOD: sqlite3_context 5479** 5480** Implementations of aggregate SQL functions use this 5481** routine to allocate memory for storing their state. 5482** 5483** ^The first time the sqlite3_aggregate_context(C,N) routine is called 5484** for a particular aggregate function, SQLite allocates 5485** N bytes of memory, zeroes out that memory, and returns a pointer 5486** to the new memory. ^On second and subsequent calls to 5487** sqlite3_aggregate_context() for the same aggregate function instance, 5488** the same buffer is returned. Sqlite3_aggregate_context() is normally 5489** called once for each invocation of the xStep callback and then one 5490** last time when the xFinal callback is invoked. ^(When no rows match 5491** an aggregate query, the xStep() callback of the aggregate function 5492** implementation is never called and xFinal() is called exactly once. 5493** In those cases, sqlite3_aggregate_context() might be called for the 5494** first time from within xFinal().)^ 5495** 5496** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 5497** when first called if N is less than or equal to zero or if a memory 5498** allocate error occurs. 5499** 5500** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 5501** determined by the N parameter on first successful call. Changing the 5502** value of N in any subsequent call to sqlite3_aggregate_context() within 5503** the same aggregate function instance will not resize the memory 5504** allocation.)^ Within the xFinal callback, it is customary to set 5505** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 5506** pointless memory allocations occur. 5507** 5508** ^SQLite automatically frees the memory allocated by 5509** sqlite3_aggregate_context() when the aggregate query concludes. 5510** 5511** The first parameter must be a copy of the 5512** [sqlite3_context | SQL function context] that is the first parameter 5513** to the xStep or xFinal callback routine that implements the aggregate 5514** function. 5515** 5516** This routine must be called from the same thread in which 5517** the aggregate SQL function is running. 5518*/ 5519void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 5520 5521/* 5522** CAPI3REF: User Data For Functions 5523** METHOD: sqlite3_context 5524** 5525** ^The sqlite3_user_data() interface returns a copy of 5526** the pointer that was the pUserData parameter (the 5th parameter) 5527** of the [sqlite3_create_function()] 5528** and [sqlite3_create_function16()] routines that originally 5529** registered the application defined function. 5530** 5531** This routine must be called from the same thread in which 5532** the application-defined function is running. 5533*/ 5534void *sqlite3_user_data(sqlite3_context*); 5535 5536/* 5537** CAPI3REF: Database Connection For Functions 5538** METHOD: sqlite3_context 5539** 5540** ^The sqlite3_context_db_handle() interface returns a copy of 5541** the pointer to the [database connection] (the 1st parameter) 5542** of the [sqlite3_create_function()] 5543** and [sqlite3_create_function16()] routines that originally 5544** registered the application defined function. 5545*/ 5546sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 5547 5548/* 5549** CAPI3REF: Function Auxiliary Data 5550** METHOD: sqlite3_context 5551** 5552** These functions may be used by (non-aggregate) SQL functions to 5553** associate metadata with argument values. If the same value is passed to 5554** multiple invocations of the same SQL function during query execution, under 5555** some circumstances the associated metadata may be preserved. An example 5556** of where this might be useful is in a regular-expression matching 5557** function. The compiled version of the regular expression can be stored as 5558** metadata associated with the pattern string. 5559** Then as long as the pattern string remains the same, 5560** the compiled regular expression can be reused on multiple 5561** invocations of the same function. 5562** 5563** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 5564** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 5565** value to the application-defined function. ^N is zero for the left-most 5566** function argument. ^If there is no metadata 5567** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 5568** returns a NULL pointer. 5569** 5570** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 5571** argument of the application-defined function. ^Subsequent 5572** calls to sqlite3_get_auxdata(C,N) return P from the most recent 5573** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5574** NULL if the metadata has been discarded. 5575** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5576** SQLite will invoke the destructor function X with parameter P exactly 5577** once, when the metadata is discarded. 5578** SQLite is free to discard the metadata at any time, including: <ul> 5579** <li> ^(when the corresponding function parameter changes)^, or 5580** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5581** SQL statement)^, or 5582** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5583** parameter)^, or 5584** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5585** allocation error occurs.)^ </ul> 5586** 5587** Note the last bullet in particular. The destructor X in 5588** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5589** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5590** should be called near the end of the function implementation and the 5591** function implementation should not make any use of P after 5592** sqlite3_set_auxdata() has been called. 5593** 5594** ^(In practice, metadata is preserved between function calls for 5595** function parameters that are compile-time constants, including literal 5596** values and [parameters] and expressions composed from the same.)^ 5597** 5598** The value of the N parameter to these interfaces should be non-negative. 5599** Future enhancements may make use of negative N values to define new 5600** kinds of function caching behavior. 5601** 5602** These routines must be called from the same thread in which 5603** the SQL function is running. 5604*/ 5605void *sqlite3_get_auxdata(sqlite3_context*, int N); 5606void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5607 5608 5609/* 5610** CAPI3REF: Constants Defining Special Destructor Behavior 5611** 5612** These are special values for the destructor that is passed in as the 5613** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5614** argument is SQLITE_STATIC, it means that the content pointer is constant 5615** and will never change. It does not need to be destroyed. ^The 5616** SQLITE_TRANSIENT value means that the content will likely change in 5617** the near future and that SQLite should make its own private copy of 5618** the content before returning. 5619** 5620** The typedef is necessary to work around problems in certain 5621** C++ compilers. 5622*/ 5623typedef void (*sqlite3_destructor_type)(void*); 5624#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5625#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5626 5627/* 5628** CAPI3REF: Setting The Result Of An SQL Function 5629** METHOD: sqlite3_context 5630** 5631** These routines are used by the xFunc or xFinal callbacks that 5632** implement SQL functions and aggregates. See 5633** [sqlite3_create_function()] and [sqlite3_create_function16()] 5634** for additional information. 5635** 5636** These functions work very much like the [parameter binding] family of 5637** functions used to bind values to host parameters in prepared statements. 5638** Refer to the [SQL parameter] documentation for additional information. 5639** 5640** ^The sqlite3_result_blob() interface sets the result from 5641** an application-defined function to be the BLOB whose content is pointed 5642** to by the second parameter and which is N bytes long where N is the 5643** third parameter. 5644** 5645** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5646** interfaces set the result of the application-defined function to be 5647** a BLOB containing all zero bytes and N bytes in size. 5648** 5649** ^The sqlite3_result_double() interface sets the result from 5650** an application-defined function to be a floating point value specified 5651** by its 2nd argument. 5652** 5653** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5654** cause the implemented SQL function to throw an exception. 5655** ^SQLite uses the string pointed to by the 5656** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5657** as the text of an error message. ^SQLite interprets the error 5658** message string from sqlite3_result_error() as UTF-8. ^SQLite 5659** interprets the string from sqlite3_result_error16() as UTF-16 using 5660** the same [byte-order determination rules] as [sqlite3_bind_text16()]. 5661** ^If the third parameter to sqlite3_result_error() 5662** or sqlite3_result_error16() is negative then SQLite takes as the error 5663** message all text up through the first zero character. 5664** ^If the third parameter to sqlite3_result_error() or 5665** sqlite3_result_error16() is non-negative then SQLite takes that many 5666** bytes (not characters) from the 2nd parameter as the error message. 5667** ^The sqlite3_result_error() and sqlite3_result_error16() 5668** routines make a private copy of the error message text before 5669** they return. Hence, the calling function can deallocate or 5670** modify the text after they return without harm. 5671** ^The sqlite3_result_error_code() function changes the error code 5672** returned by SQLite as a result of an error in a function. ^By default, 5673** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5674** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5675** 5676** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5677** error indicating that a string or BLOB is too long to represent. 5678** 5679** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5680** error indicating that a memory allocation failed. 5681** 5682** ^The sqlite3_result_int() interface sets the return value 5683** of the application-defined function to be the 32-bit signed integer 5684** value given in the 2nd argument. 5685** ^The sqlite3_result_int64() interface sets the return value 5686** of the application-defined function to be the 64-bit signed integer 5687** value given in the 2nd argument. 5688** 5689** ^The sqlite3_result_null() interface sets the return value 5690** of the application-defined function to be NULL. 5691** 5692** ^The sqlite3_result_text(), sqlite3_result_text16(), 5693** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5694** set the return value of the application-defined function to be 5695** a text string which is represented as UTF-8, UTF-16 native byte order, 5696** UTF-16 little endian, or UTF-16 big endian, respectively. 5697** ^The sqlite3_result_text64() interface sets the return value of an 5698** application-defined function to be a text string in an encoding 5699** specified by the fifth (and last) parameter, which must be one 5700** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5701** ^SQLite takes the text result from the application from 5702** the 2nd parameter of the sqlite3_result_text* interfaces. 5703** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5704** is negative, then SQLite takes result text from the 2nd parameter 5705** through the first zero character. 5706** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5707** is non-negative, then as many bytes (not characters) of the text 5708** pointed to by the 2nd parameter are taken as the application-defined 5709** function result. If the 3rd parameter is non-negative, then it 5710** must be the byte offset into the string where the NUL terminator would 5711** appear if the string where NUL terminated. If any NUL characters occur 5712** in the string at a byte offset that is less than the value of the 3rd 5713** parameter, then the resulting string will contain embedded NULs and the 5714** result of expressions operating on strings with embedded NULs is undefined. 5715** ^If the 4th parameter to the sqlite3_result_text* interfaces 5716** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5717** function as the destructor on the text or BLOB result when it has 5718** finished using that result. 5719** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5720** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5721** assumes that the text or BLOB result is in constant space and does not 5722** copy the content of the parameter nor call a destructor on the content 5723** when it has finished using that result. 5724** ^If the 4th parameter to the sqlite3_result_text* interfaces 5725** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5726** then SQLite makes a copy of the result into space obtained 5727** from [sqlite3_malloc()] before it returns. 5728** 5729** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and 5730** sqlite3_result_text16be() routines, and for sqlite3_result_text64() 5731** when the encoding is not UTF8, if the input UTF16 begins with a 5732** byte-order mark (BOM, U+FEFF) then the BOM is removed from the 5733** string and the rest of the string is interpreted according to the 5734** byte-order specified by the BOM. ^The byte-order specified by 5735** the BOM at the beginning of the text overrides the byte-order 5736** specified by the interface procedure. ^So, for example, if 5737** sqlite3_result_text16le() is invoked with text that begins 5738** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the 5739** first two bytes of input are skipped and the remaining input 5740** is interpreted as UTF16BE text. 5741** 5742** ^For UTF16 input text to the sqlite3_result_text16(), 5743** sqlite3_result_text16be(), sqlite3_result_text16le(), and 5744** sqlite3_result_text64() routines, if the text contains invalid 5745** UTF16 characters, the invalid characters might be converted 5746** into the unicode replacement character, U+FFFD. 5747** 5748** ^The sqlite3_result_value() interface sets the result of 5749** the application-defined function to be a copy of the 5750** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5751** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5752** so that the [sqlite3_value] specified in the parameter may change or 5753** be deallocated after sqlite3_result_value() returns without harm. 5754** ^A [protected sqlite3_value] object may always be used where an 5755** [unprotected sqlite3_value] object is required, so either 5756** kind of [sqlite3_value] object can be used with this interface. 5757** 5758** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5759** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5760** also associates the host-language pointer P or type T with that 5761** NULL value such that the pointer can be retrieved within an 5762** [application-defined SQL function] using [sqlite3_value_pointer()]. 5763** ^If the D parameter is not NULL, then it is a pointer to a destructor 5764** for the P parameter. ^SQLite invokes D with P as its only argument 5765** when SQLite is finished with P. The T parameter should be a static 5766** string and preferably a string literal. The sqlite3_result_pointer() 5767** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5768** 5769** If these routines are called from within the different thread 5770** than the one containing the application-defined function that received 5771** the [sqlite3_context] pointer, the results are undefined. 5772*/ 5773void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5774void sqlite3_result_blob64(sqlite3_context*,const void*, 5775 sqlite3_uint64,void(*)(void*)); 5776void sqlite3_result_double(sqlite3_context*, double); 5777void sqlite3_result_error(sqlite3_context*, const char*, int); 5778void sqlite3_result_error16(sqlite3_context*, const void*, int); 5779void sqlite3_result_error_toobig(sqlite3_context*); 5780void sqlite3_result_error_nomem(sqlite3_context*); 5781void sqlite3_result_error_code(sqlite3_context*, int); 5782void sqlite3_result_int(sqlite3_context*, int); 5783void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5784void sqlite3_result_null(sqlite3_context*); 5785void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5786void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5787 void(*)(void*), unsigned char encoding); 5788void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5789void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5790void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5791void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5792void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5793void sqlite3_result_zeroblob(sqlite3_context*, int n); 5794int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5795 5796 5797/* 5798** CAPI3REF: Setting The Subtype Of An SQL Function 5799** METHOD: sqlite3_context 5800** 5801** The sqlite3_result_subtype(C,T) function causes the subtype of 5802** the result from the [application-defined SQL function] with 5803** [sqlite3_context] C to be the value T. Only the lower 8 bits 5804** of the subtype T are preserved in current versions of SQLite; 5805** higher order bits are discarded. 5806** The number of subtype bytes preserved by SQLite might increase 5807** in future releases of SQLite. 5808*/ 5809void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5810 5811/* 5812** CAPI3REF: Define New Collating Sequences 5813** METHOD: sqlite3 5814** 5815** ^These functions add, remove, or modify a [collation] associated 5816** with the [database connection] specified as the first argument. 5817** 5818** ^The name of the collation is a UTF-8 string 5819** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5820** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5821** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5822** considered to be the same name. 5823** 5824** ^(The third argument (eTextRep) must be one of the constants: 5825** <ul> 5826** <li> [SQLITE_UTF8], 5827** <li> [SQLITE_UTF16LE], 5828** <li> [SQLITE_UTF16BE], 5829** <li> [SQLITE_UTF16], or 5830** <li> [SQLITE_UTF16_ALIGNED]. 5831** </ul>)^ 5832** ^The eTextRep argument determines the encoding of strings passed 5833** to the collating function callback, xCompare. 5834** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5835** force strings to be UTF16 with native byte order. 5836** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5837** on an even byte address. 5838** 5839** ^The fourth argument, pArg, is an application data pointer that is passed 5840** through as the first argument to the collating function callback. 5841** 5842** ^The fifth argument, xCompare, is a pointer to the collating function. 5843** ^Multiple collating functions can be registered using the same name but 5844** with different eTextRep parameters and SQLite will use whichever 5845** function requires the least amount of data transformation. 5846** ^If the xCompare argument is NULL then the collating function is 5847** deleted. ^When all collating functions having the same name are deleted, 5848** that collation is no longer usable. 5849** 5850** ^The collating function callback is invoked with a copy of the pArg 5851** application data pointer and with two strings in the encoding specified 5852** by the eTextRep argument. The two integer parameters to the collating 5853** function callback are the length of the two strings, in bytes. The collating 5854** function must return an integer that is negative, zero, or positive 5855** if the first string is less than, equal to, or greater than the second, 5856** respectively. A collating function must always return the same answer 5857** given the same inputs. If two or more collating functions are registered 5858** to the same collation name (using different eTextRep values) then all 5859** must give an equivalent answer when invoked with equivalent strings. 5860** The collating function must obey the following properties for all 5861** strings A, B, and C: 5862** 5863** <ol> 5864** <li> If A==B then B==A. 5865** <li> If A==B and B==C then A==C. 5866** <li> If A<B THEN B>A. 5867** <li> If A<B and B<C then A<C. 5868** </ol> 5869** 5870** If a collating function fails any of the above constraints and that 5871** collating function is registered and used, then the behavior of SQLite 5872** is undefined. 5873** 5874** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5875** with the addition that the xDestroy callback is invoked on pArg when 5876** the collating function is deleted. 5877** ^Collating functions are deleted when they are overridden by later 5878** calls to the collation creation functions or when the 5879** [database connection] is closed using [sqlite3_close()]. 5880** 5881** ^The xDestroy callback is <u>not</u> called if the 5882** sqlite3_create_collation_v2() function fails. Applications that invoke 5883** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5884** check the return code and dispose of the application data pointer 5885** themselves rather than expecting SQLite to deal with it for them. 5886** This is different from every other SQLite interface. The inconsistency 5887** is unfortunate but cannot be changed without breaking backwards 5888** compatibility. 5889** 5890** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5891*/ 5892int sqlite3_create_collation( 5893 sqlite3*, 5894 const char *zName, 5895 int eTextRep, 5896 void *pArg, 5897 int(*xCompare)(void*,int,const void*,int,const void*) 5898); 5899int sqlite3_create_collation_v2( 5900 sqlite3*, 5901 const char *zName, 5902 int eTextRep, 5903 void *pArg, 5904 int(*xCompare)(void*,int,const void*,int,const void*), 5905 void(*xDestroy)(void*) 5906); 5907int sqlite3_create_collation16( 5908 sqlite3*, 5909 const void *zName, 5910 int eTextRep, 5911 void *pArg, 5912 int(*xCompare)(void*,int,const void*,int,const void*) 5913); 5914 5915/* 5916** CAPI3REF: Collation Needed Callbacks 5917** METHOD: sqlite3 5918** 5919** ^To avoid having to register all collation sequences before a database 5920** can be used, a single callback function may be registered with the 5921** [database connection] to be invoked whenever an undefined collation 5922** sequence is required. 5923** 5924** ^If the function is registered using the sqlite3_collation_needed() API, 5925** then it is passed the names of undefined collation sequences as strings 5926** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5927** the names are passed as UTF-16 in machine native byte order. 5928** ^A call to either function replaces the existing collation-needed callback. 5929** 5930** ^(When the callback is invoked, the first argument passed is a copy 5931** of the second argument to sqlite3_collation_needed() or 5932** sqlite3_collation_needed16(). The second argument is the database 5933** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5934** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5935** sequence function required. The fourth parameter is the name of the 5936** required collation sequence.)^ 5937** 5938** The callback function should register the desired collation using 5939** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5940** [sqlite3_create_collation_v2()]. 5941*/ 5942int sqlite3_collation_needed( 5943 sqlite3*, 5944 void*, 5945 void(*)(void*,sqlite3*,int eTextRep,const char*) 5946); 5947int sqlite3_collation_needed16( 5948 sqlite3*, 5949 void*, 5950 void(*)(void*,sqlite3*,int eTextRep,const void*) 5951); 5952 5953#ifdef SQLITE_ENABLE_CEROD 5954/* 5955** Specify the activation key for a CEROD database. Unless 5956** activated, none of the CEROD routines will work. 5957*/ 5958void sqlite3_activate_cerod( 5959 const char *zPassPhrase /* Activation phrase */ 5960); 5961#endif 5962 5963/* 5964** CAPI3REF: Suspend Execution For A Short Time 5965** 5966** The sqlite3_sleep() function causes the current thread to suspend execution 5967** for at least a number of milliseconds specified in its parameter. 5968** 5969** If the operating system does not support sleep requests with 5970** millisecond time resolution, then the time will be rounded up to 5971** the nearest second. The number of milliseconds of sleep actually 5972** requested from the operating system is returned. 5973** 5974** ^SQLite implements this interface by calling the xSleep() 5975** method of the default [sqlite3_vfs] object. If the xSleep() method 5976** of the default VFS is not implemented correctly, or not implemented at 5977** all, then the behavior of sqlite3_sleep() may deviate from the description 5978** in the previous paragraphs. 5979*/ 5980int sqlite3_sleep(int); 5981 5982/* 5983** CAPI3REF: Name Of The Folder Holding Temporary Files 5984** 5985** ^(If this global variable is made to point to a string which is 5986** the name of a folder (a.k.a. directory), then all temporary files 5987** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5988** will be placed in that directory.)^ ^If this variable 5989** is a NULL pointer, then SQLite performs a search for an appropriate 5990** temporary file directory. 5991** 5992** Applications are strongly discouraged from using this global variable. 5993** It is required to set a temporary folder on Windows Runtime (WinRT). 5994** But for all other platforms, it is highly recommended that applications 5995** neither read nor write this variable. This global variable is a relic 5996** that exists for backwards compatibility of legacy applications and should 5997** be avoided in new projects. 5998** 5999** It is not safe to read or modify this variable in more than one 6000** thread at a time. It is not safe to read or modify this variable 6001** if a [database connection] is being used at the same time in a separate 6002** thread. 6003** It is intended that this variable be set once 6004** as part of process initialization and before any SQLite interface 6005** routines have been called and that this variable remain unchanged 6006** thereafter. 6007** 6008** ^The [temp_store_directory pragma] may modify this variable and cause 6009** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6010** the [temp_store_directory pragma] always assumes that any string 6011** that this variable points to is held in memory obtained from 6012** [sqlite3_malloc] and the pragma may attempt to free that memory 6013** using [sqlite3_free]. 6014** Hence, if this variable is modified directly, either it should be 6015** made NULL or made to point to memory obtained from [sqlite3_malloc] 6016** or else the use of the [temp_store_directory pragma] should be avoided. 6017** Except when requested by the [temp_store_directory pragma], SQLite 6018** does not free the memory that sqlite3_temp_directory points to. If 6019** the application wants that memory to be freed, it must do 6020** so itself, taking care to only do so after all [database connection] 6021** objects have been destroyed. 6022** 6023** <b>Note to Windows Runtime users:</b> The temporary directory must be set 6024** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 6025** features that require the use of temporary files may fail. Here is an 6026** example of how to do this using C++ with the Windows Runtime: 6027** 6028** <blockquote><pre> 6029** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 6030** TemporaryFolder->Path->Data(); 6031** char zPathBuf[MAX_PATH + 1]; 6032** memset(zPathBuf, 0, sizeof(zPathBuf)); 6033** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 6034** NULL, NULL); 6035** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 6036** </pre></blockquote> 6037*/ 6038SQLITE_EXTERN char *sqlite3_temp_directory; 6039 6040/* 6041** CAPI3REF: Name Of The Folder Holding Database Files 6042** 6043** ^(If this global variable is made to point to a string which is 6044** the name of a folder (a.k.a. directory), then all database files 6045** specified with a relative pathname and created or accessed by 6046** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 6047** to be relative to that directory.)^ ^If this variable is a NULL 6048** pointer, then SQLite assumes that all database files specified 6049** with a relative pathname are relative to the current directory 6050** for the process. Only the windows VFS makes use of this global 6051** variable; it is ignored by the unix VFS. 6052** 6053** Changing the value of this variable while a database connection is 6054** open can result in a corrupt database. 6055** 6056** It is not safe to read or modify this variable in more than one 6057** thread at a time. It is not safe to read or modify this variable 6058** if a [database connection] is being used at the same time in a separate 6059** thread. 6060** It is intended that this variable be set once 6061** as part of process initialization and before any SQLite interface 6062** routines have been called and that this variable remain unchanged 6063** thereafter. 6064** 6065** ^The [data_store_directory pragma] may modify this variable and cause 6066** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6067** the [data_store_directory pragma] always assumes that any string 6068** that this variable points to is held in memory obtained from 6069** [sqlite3_malloc] and the pragma may attempt to free that memory 6070** using [sqlite3_free]. 6071** Hence, if this variable is modified directly, either it should be 6072** made NULL or made to point to memory obtained from [sqlite3_malloc] 6073** or else the use of the [data_store_directory pragma] should be avoided. 6074*/ 6075SQLITE_EXTERN char *sqlite3_data_directory; 6076 6077/* 6078** CAPI3REF: Win32 Specific Interface 6079** 6080** These interfaces are available only on Windows. The 6081** [sqlite3_win32_set_directory] interface is used to set the value associated 6082** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to 6083** zValue, depending on the value of the type parameter. The zValue parameter 6084** should be NULL to cause the previous value to be freed via [sqlite3_free]; 6085** a non-NULL value will be copied into memory obtained from [sqlite3_malloc] 6086** prior to being used. The [sqlite3_win32_set_directory] interface returns 6087** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported, 6088** or [SQLITE_NOMEM] if memory could not be allocated. The value of the 6089** [sqlite3_data_directory] variable is intended to act as a replacement for 6090** the current directory on the sub-platforms of Win32 where that concept is 6091** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and 6092** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the 6093** sqlite3_win32_set_directory interface except the string parameter must be 6094** UTF-8 or UTF-16, respectively. 6095*/ 6096int sqlite3_win32_set_directory( 6097 unsigned long type, /* Identifier for directory being set or reset */ 6098 void *zValue /* New value for directory being set or reset */ 6099); 6100int sqlite3_win32_set_directory8(unsigned long type, const char *zValue); 6101int sqlite3_win32_set_directory16(unsigned long type, const void *zValue); 6102 6103/* 6104** CAPI3REF: Win32 Directory Types 6105** 6106** These macros are only available on Windows. They define the allowed values 6107** for the type argument to the [sqlite3_win32_set_directory] interface. 6108*/ 6109#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1 6110#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2 6111 6112/* 6113** CAPI3REF: Test For Auto-Commit Mode 6114** KEYWORDS: {autocommit mode} 6115** METHOD: sqlite3 6116** 6117** ^The sqlite3_get_autocommit() interface returns non-zero or 6118** zero if the given database connection is or is not in autocommit mode, 6119** respectively. ^Autocommit mode is on by default. 6120** ^Autocommit mode is disabled by a [BEGIN] statement. 6121** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 6122** 6123** If certain kinds of errors occur on a statement within a multi-statement 6124** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 6125** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 6126** transaction might be rolled back automatically. The only way to 6127** find out whether SQLite automatically rolled back the transaction after 6128** an error is to use this function. 6129** 6130** If another thread changes the autocommit status of the database 6131** connection while this routine is running, then the return value 6132** is undefined. 6133*/ 6134int sqlite3_get_autocommit(sqlite3*); 6135 6136/* 6137** CAPI3REF: Find The Database Handle Of A Prepared Statement 6138** METHOD: sqlite3_stmt 6139** 6140** ^The sqlite3_db_handle interface returns the [database connection] handle 6141** to which a [prepared statement] belongs. ^The [database connection] 6142** returned by sqlite3_db_handle is the same [database connection] 6143** that was the first argument 6144** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 6145** create the statement in the first place. 6146*/ 6147sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 6148 6149/* 6150** CAPI3REF: Return The Filename For A Database Connection 6151** METHOD: sqlite3 6152** 6153** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename 6154** associated with database N of connection D. 6155** ^If there is no attached database N on the database 6156** connection D, or if database N is a temporary or in-memory database, then 6157** this function will return either a NULL pointer or an empty string. 6158** 6159** ^The string value returned by this routine is owned and managed by 6160** the database connection. ^The value will be valid until the database N 6161** is [DETACH]-ed or until the database connection closes. 6162** 6163** ^The filename returned by this function is the output of the 6164** xFullPathname method of the [VFS]. ^In other words, the filename 6165** will be an absolute pathname, even if the filename used 6166** to open the database originally was a URI or relative pathname. 6167** 6168** If the filename pointer returned by this routine is not NULL, then it 6169** can be used as the filename input parameter to these routines: 6170** <ul> 6171** <li> [sqlite3_uri_parameter()] 6172** <li> [sqlite3_uri_boolean()] 6173** <li> [sqlite3_uri_int64()] 6174** <li> [sqlite3_filename_database()] 6175** <li> [sqlite3_filename_journal()] 6176** <li> [sqlite3_filename_wal()] 6177** </ul> 6178*/ 6179const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 6180 6181/* 6182** CAPI3REF: Determine if a database is read-only 6183** METHOD: sqlite3 6184** 6185** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 6186** of connection D is read-only, 0 if it is read/write, or -1 if N is not 6187** the name of a database on connection D. 6188*/ 6189int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 6190 6191/* 6192** CAPI3REF: Determine the transaction state of a database 6193** METHOD: sqlite3 6194** 6195** ^The sqlite3_txn_state(D,S) interface returns the current 6196** [transaction state] of schema S in database connection D. ^If S is NULL, 6197** then the highest transaction state of any schema on database connection D 6198** is returned. Transaction states are (in order of lowest to highest): 6199** <ol> 6200** <li value="0"> SQLITE_TXN_NONE 6201** <li value="1"> SQLITE_TXN_READ 6202** <li value="2"> SQLITE_TXN_WRITE 6203** </ol> 6204** ^If the S argument to sqlite3_txn_state(D,S) is not the name of 6205** a valid schema, then -1 is returned. 6206*/ 6207int sqlite3_txn_state(sqlite3*,const char *zSchema); 6208 6209/* 6210** CAPI3REF: Allowed return values from [sqlite3_txn_state()] 6211** KEYWORDS: {transaction state} 6212** 6213** These constants define the current transaction state of a database file. 6214** ^The [sqlite3_txn_state(D,S)] interface returns one of these 6215** constants in order to describe the transaction state of schema S 6216** in [database connection] D. 6217** 6218** <dl> 6219** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt> 6220** <dd>The SQLITE_TXN_NONE state means that no transaction is currently 6221** pending.</dd> 6222** 6223** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt> 6224** <dd>The SQLITE_TXN_READ state means that the database is currently 6225** in a read transaction. Content has been read from the database file 6226** but nothing in the database file has changed. The transaction state 6227** will advanced to SQLITE_TXN_WRITE if any changes occur and there are 6228** no other conflicting concurrent write transactions. The transaction 6229** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or 6230** [COMMIT].</dd> 6231** 6232** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt> 6233** <dd>The SQLITE_TXN_WRITE state means that the database is currently 6234** in a write transaction. Content has been written to the database file 6235** but has not yet committed. The transaction state will change to 6236** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd> 6237*/ 6238#define SQLITE_TXN_NONE 0 6239#define SQLITE_TXN_READ 1 6240#define SQLITE_TXN_WRITE 2 6241 6242/* 6243** CAPI3REF: Find the next prepared statement 6244** METHOD: sqlite3 6245** 6246** ^This interface returns a pointer to the next [prepared statement] after 6247** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 6248** then this interface returns a pointer to the first prepared statement 6249** associated with the database connection pDb. ^If no prepared statement 6250** satisfies the conditions of this routine, it returns NULL. 6251** 6252** The [database connection] pointer D in a call to 6253** [sqlite3_next_stmt(D,S)] must refer to an open database 6254** connection and in particular must not be a NULL pointer. 6255*/ 6256sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 6257 6258/* 6259** CAPI3REF: Commit And Rollback Notification Callbacks 6260** METHOD: sqlite3 6261** 6262** ^The sqlite3_commit_hook() interface registers a callback 6263** function to be invoked whenever a transaction is [COMMIT | committed]. 6264** ^Any callback set by a previous call to sqlite3_commit_hook() 6265** for the same database connection is overridden. 6266** ^The sqlite3_rollback_hook() interface registers a callback 6267** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 6268** ^Any callback set by a previous call to sqlite3_rollback_hook() 6269** for the same database connection is overridden. 6270** ^The pArg argument is passed through to the callback. 6271** ^If the callback on a commit hook function returns non-zero, 6272** then the commit is converted into a rollback. 6273** 6274** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 6275** return the P argument from the previous call of the same function 6276** on the same [database connection] D, or NULL for 6277** the first call for each function on D. 6278** 6279** The commit and rollback hook callbacks are not reentrant. 6280** The callback implementation must not do anything that will modify 6281** the database connection that invoked the callback. Any actions 6282** to modify the database connection must be deferred until after the 6283** completion of the [sqlite3_step()] call that triggered the commit 6284** or rollback hook in the first place. 6285** Note that running any other SQL statements, including SELECT statements, 6286** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 6287** the database connections for the meaning of "modify" in this paragraph. 6288** 6289** ^Registering a NULL function disables the callback. 6290** 6291** ^When the commit hook callback routine returns zero, the [COMMIT] 6292** operation is allowed to continue normally. ^If the commit hook 6293** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 6294** ^The rollback hook is invoked on a rollback that results from a commit 6295** hook returning non-zero, just as it would be with any other rollback. 6296** 6297** ^For the purposes of this API, a transaction is said to have been 6298** rolled back if an explicit "ROLLBACK" statement is executed, or 6299** an error or constraint causes an implicit rollback to occur. 6300** ^The rollback callback is not invoked if a transaction is 6301** automatically rolled back because the database connection is closed. 6302** 6303** See also the [sqlite3_update_hook()] interface. 6304*/ 6305void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 6306void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 6307 6308/* 6309** CAPI3REF: Data Change Notification Callbacks 6310** METHOD: sqlite3 6311** 6312** ^The sqlite3_update_hook() interface registers a callback function 6313** with the [database connection] identified by the first argument 6314** to be invoked whenever a row is updated, inserted or deleted in 6315** a [rowid table]. 6316** ^Any callback set by a previous call to this function 6317** for the same database connection is overridden. 6318** 6319** ^The second argument is a pointer to the function to invoke when a 6320** row is updated, inserted or deleted in a rowid table. 6321** ^The first argument to the callback is a copy of the third argument 6322** to sqlite3_update_hook(). 6323** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 6324** or [SQLITE_UPDATE], depending on the operation that caused the callback 6325** to be invoked. 6326** ^The third and fourth arguments to the callback contain pointers to the 6327** database and table name containing the affected row. 6328** ^The final callback parameter is the [rowid] of the row. 6329** ^In the case of an update, this is the [rowid] after the update takes place. 6330** 6331** ^(The update hook is not invoked when internal system tables are 6332** modified (i.e. sqlite_sequence).)^ 6333** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 6334** 6335** ^In the current implementation, the update hook 6336** is not invoked when conflicting rows are deleted because of an 6337** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 6338** invoked when rows are deleted using the [truncate optimization]. 6339** The exceptions defined in this paragraph might change in a future 6340** release of SQLite. 6341** 6342** The update hook implementation must not do anything that will modify 6343** the database connection that invoked the update hook. Any actions 6344** to modify the database connection must be deferred until after the 6345** completion of the [sqlite3_step()] call that triggered the update hook. 6346** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 6347** database connections for the meaning of "modify" in this paragraph. 6348** 6349** ^The sqlite3_update_hook(D,C,P) function 6350** returns the P argument from the previous call 6351** on the same [database connection] D, or NULL for 6352** the first call on D. 6353** 6354** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 6355** and [sqlite3_preupdate_hook()] interfaces. 6356*/ 6357void *sqlite3_update_hook( 6358 sqlite3*, 6359 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 6360 void* 6361); 6362 6363/* 6364** CAPI3REF: Enable Or Disable Shared Pager Cache 6365** 6366** ^(This routine enables or disables the sharing of the database cache 6367** and schema data structures between [database connection | connections] 6368** to the same database. Sharing is enabled if the argument is true 6369** and disabled if the argument is false.)^ 6370** 6371** ^Cache sharing is enabled and disabled for an entire process. 6372** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 6373** In prior versions of SQLite, 6374** sharing was enabled or disabled for each thread separately. 6375** 6376** ^(The cache sharing mode set by this interface effects all subsequent 6377** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 6378** Existing database connections continue to use the sharing mode 6379** that was in effect at the time they were opened.)^ 6380** 6381** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 6382** successfully. An [error code] is returned otherwise.)^ 6383** 6384** ^Shared cache is disabled by default. It is recommended that it stay 6385** that way. In other words, do not use this routine. This interface 6386** continues to be provided for historical compatibility, but its use is 6387** discouraged. Any use of shared cache is discouraged. If shared cache 6388** must be used, it is recommended that shared cache only be enabled for 6389** individual database connections using the [sqlite3_open_v2()] interface 6390** with the [SQLITE_OPEN_SHAREDCACHE] flag. 6391** 6392** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 6393** and will always return SQLITE_MISUSE. On those systems, 6394** shared cache mode should be enabled per-database connection via 6395** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 6396** 6397** This interface is threadsafe on processors where writing a 6398** 32-bit integer is atomic. 6399** 6400** See Also: [SQLite Shared-Cache Mode] 6401*/ 6402int sqlite3_enable_shared_cache(int); 6403 6404/* 6405** CAPI3REF: Attempt To Free Heap Memory 6406** 6407** ^The sqlite3_release_memory() interface attempts to free N bytes 6408** of heap memory by deallocating non-essential memory allocations 6409** held by the database library. Memory used to cache database 6410** pages to improve performance is an example of non-essential memory. 6411** ^sqlite3_release_memory() returns the number of bytes actually freed, 6412** which might be more or less than the amount requested. 6413** ^The sqlite3_release_memory() routine is a no-op returning zero 6414** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 6415** 6416** See also: [sqlite3_db_release_memory()] 6417*/ 6418int sqlite3_release_memory(int); 6419 6420/* 6421** CAPI3REF: Free Memory Used By A Database Connection 6422** METHOD: sqlite3 6423** 6424** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 6425** memory as possible from database connection D. Unlike the 6426** [sqlite3_release_memory()] interface, this interface is in effect even 6427** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 6428** omitted. 6429** 6430** See also: [sqlite3_release_memory()] 6431*/ 6432int sqlite3_db_release_memory(sqlite3*); 6433 6434/* 6435** CAPI3REF: Impose A Limit On Heap Size 6436** 6437** These interfaces impose limits on the amount of heap memory that will be 6438** by all database connections within a single process. 6439** 6440** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 6441** soft limit on the amount of heap memory that may be allocated by SQLite. 6442** ^SQLite strives to keep heap memory utilization below the soft heap 6443** limit by reducing the number of pages held in the page cache 6444** as heap memory usages approaches the limit. 6445** ^The soft heap limit is "soft" because even though SQLite strives to stay 6446** below the limit, it will exceed the limit rather than generate 6447** an [SQLITE_NOMEM] error. In other words, the soft heap limit 6448** is advisory only. 6449** 6450** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of 6451** N bytes on the amount of memory that will be allocated. ^The 6452** sqlite3_hard_heap_limit64(N) interface is similar to 6453** sqlite3_soft_heap_limit64(N) except that memory allocations will fail 6454** when the hard heap limit is reached. 6455** 6456** ^The return value from both sqlite3_soft_heap_limit64() and 6457** sqlite3_hard_heap_limit64() is the size of 6458** the heap limit prior to the call, or negative in the case of an 6459** error. ^If the argument N is negative 6460** then no change is made to the heap limit. Hence, the current 6461** size of heap limits can be determined by invoking 6462** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1). 6463** 6464** ^Setting the heap limits to zero disables the heap limiter mechanism. 6465** 6466** ^The soft heap limit may not be greater than the hard heap limit. 6467** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N) 6468** is invoked with a value of N that is greater than the hard heap limit, 6469** the the soft heap limit is set to the value of the hard heap limit. 6470** ^The soft heap limit is automatically enabled whenever the hard heap 6471** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and 6472** the soft heap limit is outside the range of 1..N, then the soft heap 6473** limit is set to N. ^Invoking sqlite3_soft_heap_limit64(0) when the 6474** hard heap limit is enabled makes the soft heap limit equal to the 6475** hard heap limit. 6476** 6477** The memory allocation limits can also be adjusted using 6478** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit]. 6479** 6480** ^(The heap limits are not enforced in the current implementation 6481** if one or more of following conditions are true: 6482** 6483** <ul> 6484** <li> The limit value is set to zero. 6485** <li> Memory accounting is disabled using a combination of the 6486** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 6487** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 6488** <li> An alternative page cache implementation is specified using 6489** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 6490** <li> The page cache allocates from its own memory pool supplied 6491** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 6492** from the heap. 6493** </ul>)^ 6494** 6495** The circumstances under which SQLite will enforce the heap limits may 6496** changes in future releases of SQLite. 6497*/ 6498sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 6499sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N); 6500 6501/* 6502** CAPI3REF: Deprecated Soft Heap Limit Interface 6503** DEPRECATED 6504** 6505** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 6506** interface. This routine is provided for historical compatibility 6507** only. All new applications should use the 6508** [sqlite3_soft_heap_limit64()] interface rather than this one. 6509*/ 6510SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 6511 6512 6513/* 6514** CAPI3REF: Extract Metadata About A Column Of A Table 6515** METHOD: sqlite3 6516** 6517** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 6518** information about column C of table T in database D 6519** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 6520** interface returns SQLITE_OK and fills in the non-NULL pointers in 6521** the final five arguments with appropriate values if the specified 6522** column exists. ^The sqlite3_table_column_metadata() interface returns 6523** SQLITE_ERROR if the specified column does not exist. 6524** ^If the column-name parameter to sqlite3_table_column_metadata() is a 6525** NULL pointer, then this routine simply checks for the existence of the 6526** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 6527** does not. If the table name parameter T in a call to 6528** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 6529** undefined behavior. 6530** 6531** ^The column is identified by the second, third and fourth parameters to 6532** this function. ^(The second parameter is either the name of the database 6533** (i.e. "main", "temp", or an attached database) containing the specified 6534** table or NULL.)^ ^If it is NULL, then all attached databases are searched 6535** for the table using the same algorithm used by the database engine to 6536** resolve unqualified table references. 6537** 6538** ^The third and fourth parameters to this function are the table and column 6539** name of the desired column, respectively. 6540** 6541** ^Metadata is returned by writing to the memory locations passed as the 5th 6542** and subsequent parameters to this function. ^Any of these arguments may be 6543** NULL, in which case the corresponding element of metadata is omitted. 6544** 6545** ^(<blockquote> 6546** <table border="1"> 6547** <tr><th> Parameter <th> Output<br>Type <th> Description 6548** 6549** <tr><td> 5th <td> const char* <td> Data type 6550** <tr><td> 6th <td> const char* <td> Name of default collation sequence 6551** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 6552** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 6553** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 6554** </table> 6555** </blockquote>)^ 6556** 6557** ^The memory pointed to by the character pointers returned for the 6558** declaration type and collation sequence is valid until the next 6559** call to any SQLite API function. 6560** 6561** ^If the specified table is actually a view, an [error code] is returned. 6562** 6563** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 6564** is not a [WITHOUT ROWID] table and an 6565** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 6566** parameters are set for the explicitly declared column. ^(If there is no 6567** [INTEGER PRIMARY KEY] column, then the outputs 6568** for the [rowid] are set as follows: 6569** 6570** <pre> 6571** data type: "INTEGER" 6572** collation sequence: "BINARY" 6573** not null: 0 6574** primary key: 1 6575** auto increment: 0 6576** </pre>)^ 6577** 6578** ^This function causes all database schemas to be read from disk and 6579** parsed, if that has not already been done, and returns an error if 6580** any errors are encountered while loading the schema. 6581*/ 6582int sqlite3_table_column_metadata( 6583 sqlite3 *db, /* Connection handle */ 6584 const char *zDbName, /* Database name or NULL */ 6585 const char *zTableName, /* Table name */ 6586 const char *zColumnName, /* Column name */ 6587 char const **pzDataType, /* OUTPUT: Declared data type */ 6588 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 6589 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 6590 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 6591 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 6592); 6593 6594/* 6595** CAPI3REF: Load An Extension 6596** METHOD: sqlite3 6597** 6598** ^This interface loads an SQLite extension library from the named file. 6599** 6600** ^The sqlite3_load_extension() interface attempts to load an 6601** [SQLite extension] library contained in the file zFile. If 6602** the file cannot be loaded directly, attempts are made to load 6603** with various operating-system specific extensions added. 6604** So for example, if "samplelib" cannot be loaded, then names like 6605** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 6606** be tried also. 6607** 6608** ^The entry point is zProc. 6609** ^(zProc may be 0, in which case SQLite will try to come up with an 6610** entry point name on its own. It first tries "sqlite3_extension_init". 6611** If that does not work, it constructs a name "sqlite3_X_init" where the 6612** X is consists of the lower-case equivalent of all ASCII alphabetic 6613** characters in the filename from the last "/" to the first following 6614** "." and omitting any initial "lib".)^ 6615** ^The sqlite3_load_extension() interface returns 6616** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 6617** ^If an error occurs and pzErrMsg is not 0, then the 6618** [sqlite3_load_extension()] interface shall attempt to 6619** fill *pzErrMsg with error message text stored in memory 6620** obtained from [sqlite3_malloc()]. The calling function 6621** should free this memory by calling [sqlite3_free()]. 6622** 6623** ^Extension loading must be enabled using 6624** [sqlite3_enable_load_extension()] or 6625** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 6626** prior to calling this API, 6627** otherwise an error will be returned. 6628** 6629** <b>Security warning:</b> It is recommended that the 6630** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 6631** interface. The use of the [sqlite3_enable_load_extension()] interface 6632** should be avoided. This will keep the SQL function [load_extension()] 6633** disabled and prevent SQL injections from giving attackers 6634** access to extension loading capabilities. 6635** 6636** See also the [load_extension() SQL function]. 6637*/ 6638int sqlite3_load_extension( 6639 sqlite3 *db, /* Load the extension into this database connection */ 6640 const char *zFile, /* Name of the shared library containing extension */ 6641 const char *zProc, /* Entry point. Derived from zFile if 0 */ 6642 char **pzErrMsg /* Put error message here if not 0 */ 6643); 6644 6645/* 6646** CAPI3REF: Enable Or Disable Extension Loading 6647** METHOD: sqlite3 6648** 6649** ^So as not to open security holes in older applications that are 6650** unprepared to deal with [extension loading], and as a means of disabling 6651** [extension loading] while evaluating user-entered SQL, the following API 6652** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 6653** 6654** ^Extension loading is off by default. 6655** ^Call the sqlite3_enable_load_extension() routine with onoff==1 6656** to turn extension loading on and call it with onoff==0 to turn 6657** it back off again. 6658** 6659** ^This interface enables or disables both the C-API 6660** [sqlite3_load_extension()] and the SQL function [load_extension()]. 6661** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 6662** to enable or disable only the C-API.)^ 6663** 6664** <b>Security warning:</b> It is recommended that extension loading 6665** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 6666** rather than this interface, so the [load_extension()] SQL function 6667** remains disabled. This will prevent SQL injections from giving attackers 6668** access to extension loading capabilities. 6669*/ 6670int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6671 6672/* 6673** CAPI3REF: Automatically Load Statically Linked Extensions 6674** 6675** ^This interface causes the xEntryPoint() function to be invoked for 6676** each new [database connection] that is created. The idea here is that 6677** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6678** that is to be automatically loaded into all new database connections. 6679** 6680** ^(Even though the function prototype shows that xEntryPoint() takes 6681** no arguments and returns void, SQLite invokes xEntryPoint() with three 6682** arguments and expects an integer result as if the signature of the 6683** entry point where as follows: 6684** 6685** <blockquote><pre> 6686** int xEntryPoint( 6687** sqlite3 *db, 6688** const char **pzErrMsg, 6689** const struct sqlite3_api_routines *pThunk 6690** ); 6691** </pre></blockquote>)^ 6692** 6693** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6694** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6695** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6696** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6697** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6698** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6699** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6700** 6701** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6702** on the list of automatic extensions is a harmless no-op. ^No entry point 6703** will be called more than once for each database connection that is opened. 6704** 6705** See also: [sqlite3_reset_auto_extension()] 6706** and [sqlite3_cancel_auto_extension()] 6707*/ 6708int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6709 6710/* 6711** CAPI3REF: Cancel Automatic Extension Loading 6712** 6713** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6714** initialization routine X that was registered using a prior call to 6715** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6716** routine returns 1 if initialization routine X was successfully 6717** unregistered and it returns 0 if X was not on the list of initialization 6718** routines. 6719*/ 6720int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6721 6722/* 6723** CAPI3REF: Reset Automatic Extension Loading 6724** 6725** ^This interface disables all automatic extensions previously 6726** registered using [sqlite3_auto_extension()]. 6727*/ 6728void sqlite3_reset_auto_extension(void); 6729 6730/* 6731** The interface to the virtual-table mechanism is currently considered 6732** to be experimental. The interface might change in incompatible ways. 6733** If this is a problem for you, do not use the interface at this time. 6734** 6735** When the virtual-table mechanism stabilizes, we will declare the 6736** interface fixed, support it indefinitely, and remove this comment. 6737*/ 6738 6739/* 6740** Structures used by the virtual table interface 6741*/ 6742typedef struct sqlite3_vtab sqlite3_vtab; 6743typedef struct sqlite3_index_info sqlite3_index_info; 6744typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6745typedef struct sqlite3_module sqlite3_module; 6746 6747/* 6748** CAPI3REF: Virtual Table Object 6749** KEYWORDS: sqlite3_module {virtual table module} 6750** 6751** This structure, sometimes called a "virtual table module", 6752** defines the implementation of a [virtual table]. 6753** This structure consists mostly of methods for the module. 6754** 6755** ^A virtual table module is created by filling in a persistent 6756** instance of this structure and passing a pointer to that instance 6757** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6758** ^The registration remains valid until it is replaced by a different 6759** module or until the [database connection] closes. The content 6760** of this structure must not change while it is registered with 6761** any database connection. 6762*/ 6763struct sqlite3_module { 6764 int iVersion; 6765 int (*xCreate)(sqlite3*, void *pAux, 6766 int argc, const char *const*argv, 6767 sqlite3_vtab **ppVTab, char**); 6768 int (*xConnect)(sqlite3*, void *pAux, 6769 int argc, const char *const*argv, 6770 sqlite3_vtab **ppVTab, char**); 6771 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6772 int (*xDisconnect)(sqlite3_vtab *pVTab); 6773 int (*xDestroy)(sqlite3_vtab *pVTab); 6774 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6775 int (*xClose)(sqlite3_vtab_cursor*); 6776 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6777 int argc, sqlite3_value **argv); 6778 int (*xNext)(sqlite3_vtab_cursor*); 6779 int (*xEof)(sqlite3_vtab_cursor*); 6780 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6781 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6782 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6783 int (*xBegin)(sqlite3_vtab *pVTab); 6784 int (*xSync)(sqlite3_vtab *pVTab); 6785 int (*xCommit)(sqlite3_vtab *pVTab); 6786 int (*xRollback)(sqlite3_vtab *pVTab); 6787 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6788 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6789 void **ppArg); 6790 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6791 /* The methods above are in version 1 of the sqlite_module object. Those 6792 ** below are for version 2 and greater. */ 6793 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6794 int (*xRelease)(sqlite3_vtab *pVTab, int); 6795 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6796 /* The methods above are in versions 1 and 2 of the sqlite_module object. 6797 ** Those below are for version 3 and greater. */ 6798 int (*xShadowName)(const char*); 6799}; 6800 6801/* 6802** CAPI3REF: Virtual Table Indexing Information 6803** KEYWORDS: sqlite3_index_info 6804** 6805** The sqlite3_index_info structure and its substructures is used as part 6806** of the [virtual table] interface to 6807** pass information into and receive the reply from the [xBestIndex] 6808** method of a [virtual table module]. The fields under **Inputs** are the 6809** inputs to xBestIndex and are read-only. xBestIndex inserts its 6810** results into the **Outputs** fields. 6811** 6812** ^(The aConstraint[] array records WHERE clause constraints of the form: 6813** 6814** <blockquote>column OP expr</blockquote> 6815** 6816** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6817** stored in aConstraint[].op using one of the 6818** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6819** ^(The index of the column is stored in 6820** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6821** expr on the right-hand side can be evaluated (and thus the constraint 6822** is usable) and false if it cannot.)^ 6823** 6824** ^The optimizer automatically inverts terms of the form "expr OP column" 6825** and makes other simplifications to the WHERE clause in an attempt to 6826** get as many WHERE clause terms into the form shown above as possible. 6827** ^The aConstraint[] array only reports WHERE clause terms that are 6828** relevant to the particular virtual table being queried. 6829** 6830** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6831** ^Each term of aOrderBy records a column of the ORDER BY clause. 6832** 6833** The colUsed field indicates which columns of the virtual table may be 6834** required by the current scan. Virtual table columns are numbered from 6835** zero in the order in which they appear within the CREATE TABLE statement 6836** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6837** the corresponding bit is set within the colUsed mask if the column may be 6838** required by SQLite. If the table has at least 64 columns and any column 6839** to the right of the first 63 is required, then bit 63 of colUsed is also 6840** set. In other words, column iCol may be required if the expression 6841** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6842** non-zero. 6843** 6844** The [xBestIndex] method must fill aConstraintUsage[] with information 6845** about what parameters to pass to xFilter. ^If argvIndex>0 then 6846** the right-hand side of the corresponding aConstraint[] is evaluated 6847** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6848** is true, then the constraint is assumed to be fully handled by the 6849** virtual table and might not be checked again by the byte code.)^ ^(The 6850** aConstraintUsage[].omit flag is an optimization hint. When the omit flag 6851** is left in its default setting of false, the constraint will always be 6852** checked separately in byte code. If the omit flag is change to true, then 6853** the constraint may or may not be checked in byte code. In other words, 6854** when the omit flag is true there is no guarantee that the constraint will 6855** not be checked again using byte code.)^ 6856** 6857** ^The idxNum and idxPtr values are recorded and passed into the 6858** [xFilter] method. 6859** ^[sqlite3_free()] is used to free idxPtr if and only if 6860** needToFreeIdxPtr is true. 6861** 6862** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6863** the correct order to satisfy the ORDER BY clause so that no separate 6864** sorting step is required. 6865** 6866** ^The estimatedCost value is an estimate of the cost of a particular 6867** strategy. A cost of N indicates that the cost of the strategy is similar 6868** to a linear scan of an SQLite table with N rows. A cost of log(N) 6869** indicates that the expense of the operation is similar to that of a 6870** binary search on a unique indexed field of an SQLite table with N rows. 6871** 6872** ^The estimatedRows value is an estimate of the number of rows that 6873** will be returned by the strategy. 6874** 6875** The xBestIndex method may optionally populate the idxFlags field with a 6876** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6877** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6878** assumes that the strategy may visit at most one row. 6879** 6880** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6881** SQLite also assumes that if a call to the xUpdate() method is made as 6882** part of the same statement to delete or update a virtual table row and the 6883** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6884** any database changes. In other words, if the xUpdate() returns 6885** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6886** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6887** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6888** the xUpdate method are automatically rolled back by SQLite. 6889** 6890** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6891** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6892** If a virtual table extension is 6893** used with an SQLite version earlier than 3.8.2, the results of attempting 6894** to read or write the estimatedRows field are undefined (but are likely 6895** to include crashing the application). The estimatedRows field should 6896** therefore only be used if [sqlite3_libversion_number()] returns a 6897** value greater than or equal to 3008002. Similarly, the idxFlags field 6898** was added for [version 3.9.0] ([dateof:3.9.0]). 6899** It may therefore only be used if 6900** sqlite3_libversion_number() returns a value greater than or equal to 6901** 3009000. 6902*/ 6903struct sqlite3_index_info { 6904 /* Inputs */ 6905 int nConstraint; /* Number of entries in aConstraint */ 6906 struct sqlite3_index_constraint { 6907 int iColumn; /* Column constrained. -1 for ROWID */ 6908 unsigned char op; /* Constraint operator */ 6909 unsigned char usable; /* True if this constraint is usable */ 6910 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6911 } *aConstraint; /* Table of WHERE clause constraints */ 6912 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6913 struct sqlite3_index_orderby { 6914 int iColumn; /* Column number */ 6915 unsigned char desc; /* True for DESC. False for ASC. */ 6916 } *aOrderBy; /* The ORDER BY clause */ 6917 /* Outputs */ 6918 struct sqlite3_index_constraint_usage { 6919 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6920 unsigned char omit; /* Do not code a test for this constraint */ 6921 } *aConstraintUsage; 6922 int idxNum; /* Number used to identify the index */ 6923 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6924 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6925 int orderByConsumed; /* True if output is already ordered */ 6926 double estimatedCost; /* Estimated cost of using this index */ 6927 /* Fields below are only available in SQLite 3.8.2 and later */ 6928 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6929 /* Fields below are only available in SQLite 3.9.0 and later */ 6930 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6931 /* Fields below are only available in SQLite 3.10.0 and later */ 6932 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6933}; 6934 6935/* 6936** CAPI3REF: Virtual Table Scan Flags 6937** 6938** Virtual table implementations are allowed to set the 6939** [sqlite3_index_info].idxFlags field to some combination of 6940** these bits. 6941*/ 6942#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6943 6944/* 6945** CAPI3REF: Virtual Table Constraint Operator Codes 6946** 6947** These macros define the allowed values for the 6948** [sqlite3_index_info].aConstraint[].op field. Each value represents 6949** an operator that is part of a constraint term in the wHERE clause of 6950** a query that uses a [virtual table]. 6951*/ 6952#define SQLITE_INDEX_CONSTRAINT_EQ 2 6953#define SQLITE_INDEX_CONSTRAINT_GT 4 6954#define SQLITE_INDEX_CONSTRAINT_LE 8 6955#define SQLITE_INDEX_CONSTRAINT_LT 16 6956#define SQLITE_INDEX_CONSTRAINT_GE 32 6957#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6958#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6959#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6960#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6961#define SQLITE_INDEX_CONSTRAINT_NE 68 6962#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6963#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6964#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6965#define SQLITE_INDEX_CONSTRAINT_IS 72 6966#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150 6967 6968/* 6969** CAPI3REF: Register A Virtual Table Implementation 6970** METHOD: sqlite3 6971** 6972** ^These routines are used to register a new [virtual table module] name. 6973** ^Module names must be registered before 6974** creating a new [virtual table] using the module and before using a 6975** preexisting [virtual table] for the module. 6976** 6977** ^The module name is registered on the [database connection] specified 6978** by the first parameter. ^The name of the module is given by the 6979** second parameter. ^The third parameter is a pointer to 6980** the implementation of the [virtual table module]. ^The fourth 6981** parameter is an arbitrary client data pointer that is passed through 6982** into the [xCreate] and [xConnect] methods of the virtual table module 6983** when a new virtual table is be being created or reinitialized. 6984** 6985** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6986** is a pointer to a destructor for the pClientData. ^SQLite will 6987** invoke the destructor function (if it is not NULL) when SQLite 6988** no longer needs the pClientData pointer. ^The destructor will also 6989** be invoked if the call to sqlite3_create_module_v2() fails. 6990** ^The sqlite3_create_module() 6991** interface is equivalent to sqlite3_create_module_v2() with a NULL 6992** destructor. 6993** 6994** ^If the third parameter (the pointer to the sqlite3_module object) is 6995** NULL then no new module is create and any existing modules with the 6996** same name are dropped. 6997** 6998** See also: [sqlite3_drop_modules()] 6999*/ 7000int sqlite3_create_module( 7001 sqlite3 *db, /* SQLite connection to register module with */ 7002 const char *zName, /* Name of the module */ 7003 const sqlite3_module *p, /* Methods for the module */ 7004 void *pClientData /* Client data for xCreate/xConnect */ 7005); 7006int sqlite3_create_module_v2( 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 void(*xDestroy)(void*) /* Module destructor function */ 7012); 7013 7014/* 7015** CAPI3REF: Remove Unnecessary Virtual Table Implementations 7016** METHOD: sqlite3 7017** 7018** ^The sqlite3_drop_modules(D,L) interface removes all virtual 7019** table modules from database connection D except those named on list L. 7020** The L parameter must be either NULL or a pointer to an array of pointers 7021** to strings where the array is terminated by a single NULL pointer. 7022** ^If the L parameter is NULL, then all virtual table modules are removed. 7023** 7024** See also: [sqlite3_create_module()] 7025*/ 7026int sqlite3_drop_modules( 7027 sqlite3 *db, /* Remove modules from this connection */ 7028 const char **azKeep /* Except, do not remove the ones named here */ 7029); 7030 7031/* 7032** CAPI3REF: Virtual Table Instance Object 7033** KEYWORDS: sqlite3_vtab 7034** 7035** Every [virtual table module] implementation uses a subclass 7036** of this object to describe a particular instance 7037** of the [virtual table]. Each subclass will 7038** be tailored to the specific needs of the module implementation. 7039** The purpose of this superclass is to define certain fields that are 7040** common to all module implementations. 7041** 7042** ^Virtual tables methods can set an error message by assigning a 7043** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 7044** take care that any prior string is freed by a call to [sqlite3_free()] 7045** prior to assigning a new string to zErrMsg. ^After the error message 7046** is delivered up to the client application, the string will be automatically 7047** freed by sqlite3_free() and the zErrMsg field will be zeroed. 7048*/ 7049struct sqlite3_vtab { 7050 const sqlite3_module *pModule; /* The module for this virtual table */ 7051 int nRef; /* Number of open cursors */ 7052 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 7053 /* Virtual table implementations will typically add additional fields */ 7054}; 7055 7056/* 7057** CAPI3REF: Virtual Table Cursor Object 7058** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 7059** 7060** Every [virtual table module] implementation uses a subclass of the 7061** following structure to describe cursors that point into the 7062** [virtual table] and are used 7063** to loop through the virtual table. Cursors are created using the 7064** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 7065** by the [sqlite3_module.xClose | xClose] method. Cursors are used 7066** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 7067** of the module. Each module implementation will define 7068** the content of a cursor structure to suit its own needs. 7069** 7070** This superclass exists in order to define fields of the cursor that 7071** are common to all implementations. 7072*/ 7073struct sqlite3_vtab_cursor { 7074 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 7075 /* Virtual table implementations will typically add additional fields */ 7076}; 7077 7078/* 7079** CAPI3REF: Declare The Schema Of A Virtual Table 7080** 7081** ^The [xCreate] and [xConnect] methods of a 7082** [virtual table module] call this interface 7083** to declare the format (the names and datatypes of the columns) of 7084** the virtual tables they implement. 7085*/ 7086int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 7087 7088/* 7089** CAPI3REF: Overload A Function For A Virtual Table 7090** METHOD: sqlite3 7091** 7092** ^(Virtual tables can provide alternative implementations of functions 7093** using the [xFindFunction] method of the [virtual table module]. 7094** But global versions of those functions 7095** must exist in order to be overloaded.)^ 7096** 7097** ^(This API makes sure a global version of a function with a particular 7098** name and number of parameters exists. If no such function exists 7099** before this API is called, a new function is created.)^ ^The implementation 7100** of the new function always causes an exception to be thrown. So 7101** the new function is not good for anything by itself. Its only 7102** purpose is to be a placeholder function that can be overloaded 7103** by a [virtual table]. 7104*/ 7105int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 7106 7107/* 7108** The interface to the virtual-table mechanism defined above (back up 7109** to a comment remarkably similar to this one) is currently considered 7110** to be experimental. The interface might change in incompatible ways. 7111** If this is a problem for you, do not use the interface at this time. 7112** 7113** When the virtual-table mechanism stabilizes, we will declare the 7114** interface fixed, support it indefinitely, and remove this comment. 7115*/ 7116 7117/* 7118** CAPI3REF: A Handle To An Open BLOB 7119** KEYWORDS: {BLOB handle} {BLOB handles} 7120** 7121** An instance of this object represents an open BLOB on which 7122** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 7123** ^Objects of this type are created by [sqlite3_blob_open()] 7124** and destroyed by [sqlite3_blob_close()]. 7125** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 7126** can be used to read or write small subsections of the BLOB. 7127** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 7128*/ 7129typedef struct sqlite3_blob sqlite3_blob; 7130 7131/* 7132** CAPI3REF: Open A BLOB For Incremental I/O 7133** METHOD: sqlite3 7134** CONSTRUCTOR: sqlite3_blob 7135** 7136** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 7137** in row iRow, column zColumn, table zTable in database zDb; 7138** in other words, the same BLOB that would be selected by: 7139** 7140** <pre> 7141** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 7142** </pre>)^ 7143** 7144** ^(Parameter zDb is not the filename that contains the database, but 7145** rather the symbolic name of the database. For attached databases, this is 7146** the name that appears after the AS keyword in the [ATTACH] statement. 7147** For the main database file, the database name is "main". For TEMP 7148** tables, the database name is "temp".)^ 7149** 7150** ^If the flags parameter is non-zero, then the BLOB is opened for read 7151** and write access. ^If the flags parameter is zero, the BLOB is opened for 7152** read-only access. 7153** 7154** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 7155** in *ppBlob. Otherwise an [error code] is returned and, unless the error 7156** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 7157** the API is not misused, it is always safe to call [sqlite3_blob_close()] 7158** on *ppBlob after this function it returns. 7159** 7160** This function fails with SQLITE_ERROR if any of the following are true: 7161** <ul> 7162** <li> ^(Database zDb does not exist)^, 7163** <li> ^(Table zTable does not exist within database zDb)^, 7164** <li> ^(Table zTable is a WITHOUT ROWID table)^, 7165** <li> ^(Column zColumn does not exist)^, 7166** <li> ^(Row iRow is not present in the table)^, 7167** <li> ^(The specified column of row iRow contains a value that is not 7168** a TEXT or BLOB value)^, 7169** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 7170** constraint and the blob is being opened for read/write access)^, 7171** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 7172** column zColumn is part of a [child key] definition and the blob is 7173** being opened for read/write access)^. 7174** </ul> 7175** 7176** ^Unless it returns SQLITE_MISUSE, this function sets the 7177** [database connection] error code and message accessible via 7178** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7179** 7180** A BLOB referenced by sqlite3_blob_open() may be read using the 7181** [sqlite3_blob_read()] interface and modified by using 7182** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 7183** different row of the same table using the [sqlite3_blob_reopen()] 7184** interface. However, the column, table, or database of a [BLOB handle] 7185** cannot be changed after the [BLOB handle] is opened. 7186** 7187** ^(If the row that a BLOB handle points to is modified by an 7188** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 7189** then the BLOB handle is marked as "expired". 7190** This is true if any column of the row is changed, even a column 7191** other than the one the BLOB handle is open on.)^ 7192** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 7193** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 7194** ^(Changes written into a BLOB prior to the BLOB expiring are not 7195** rolled back by the expiration of the BLOB. Such changes will eventually 7196** commit if the transaction continues to completion.)^ 7197** 7198** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 7199** the opened blob. ^The size of a blob may not be changed by this 7200** interface. Use the [UPDATE] SQL command to change the size of a 7201** blob. 7202** 7203** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 7204** and the built-in [zeroblob] SQL function may be used to create a 7205** zero-filled blob to read or write using the incremental-blob interface. 7206** 7207** To avoid a resource leak, every open [BLOB handle] should eventually 7208** be released by a call to [sqlite3_blob_close()]. 7209** 7210** See also: [sqlite3_blob_close()], 7211** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 7212** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 7213*/ 7214int sqlite3_blob_open( 7215 sqlite3*, 7216 const char *zDb, 7217 const char *zTable, 7218 const char *zColumn, 7219 sqlite3_int64 iRow, 7220 int flags, 7221 sqlite3_blob **ppBlob 7222); 7223 7224/* 7225** CAPI3REF: Move a BLOB Handle to a New Row 7226** METHOD: sqlite3_blob 7227** 7228** ^This function is used to move an existing [BLOB handle] so that it points 7229** to a different row of the same database table. ^The new row is identified 7230** by the rowid value passed as the second argument. Only the row can be 7231** changed. ^The database, table and column on which the blob handle is open 7232** remain the same. Moving an existing [BLOB handle] to a new row is 7233** faster than closing the existing handle and opening a new one. 7234** 7235** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 7236** it must exist and there must be either a blob or text value stored in 7237** the nominated column.)^ ^If the new row is not present in the table, or if 7238** it does not contain a blob or text value, or if another error occurs, an 7239** SQLite error code is returned and the blob handle is considered aborted. 7240** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 7241** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 7242** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 7243** always returns zero. 7244** 7245** ^This function sets the database handle error code and message. 7246*/ 7247int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 7248 7249/* 7250** CAPI3REF: Close A BLOB Handle 7251** DESTRUCTOR: sqlite3_blob 7252** 7253** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 7254** unconditionally. Even if this routine returns an error code, the 7255** handle is still closed.)^ 7256** 7257** ^If the blob handle being closed was opened for read-write access, and if 7258** the database is in auto-commit mode and there are no other open read-write 7259** blob handles or active write statements, the current transaction is 7260** committed. ^If an error occurs while committing the transaction, an error 7261** code is returned and the transaction rolled back. 7262** 7263** Calling this function with an argument that is not a NULL pointer or an 7264** open blob handle results in undefined behaviour. ^Calling this routine 7265** with a null pointer (such as would be returned by a failed call to 7266** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 7267** is passed a valid open blob handle, the values returned by the 7268** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 7269*/ 7270int sqlite3_blob_close(sqlite3_blob *); 7271 7272/* 7273** CAPI3REF: Return The Size Of An Open BLOB 7274** METHOD: sqlite3_blob 7275** 7276** ^Returns the size in bytes of the BLOB accessible via the 7277** successfully opened [BLOB handle] in its only argument. ^The 7278** incremental blob I/O routines can only read or overwriting existing 7279** blob content; they cannot change the size of a blob. 7280** 7281** This routine only works on a [BLOB handle] which has been created 7282** by a prior successful call to [sqlite3_blob_open()] and which has not 7283** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7284** to this routine results in undefined and probably undesirable behavior. 7285*/ 7286int sqlite3_blob_bytes(sqlite3_blob *); 7287 7288/* 7289** CAPI3REF: Read Data From A BLOB Incrementally 7290** METHOD: sqlite3_blob 7291** 7292** ^(This function is used to read data from an open [BLOB handle] into a 7293** caller-supplied buffer. N bytes of data are copied into buffer Z 7294** from the open BLOB, starting at offset iOffset.)^ 7295** 7296** ^If offset iOffset is less than N bytes from the end of the BLOB, 7297** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 7298** less than zero, [SQLITE_ERROR] is returned and no data is read. 7299** ^The size of the blob (and hence the maximum value of N+iOffset) 7300** can be determined using the [sqlite3_blob_bytes()] interface. 7301** 7302** ^An attempt to read from an expired [BLOB handle] fails with an 7303** error code of [SQLITE_ABORT]. 7304** 7305** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 7306** Otherwise, an [error code] or an [extended error code] is returned.)^ 7307** 7308** This routine only works on a [BLOB handle] which has been created 7309** by a prior successful call to [sqlite3_blob_open()] and which has not 7310** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7311** to this routine results in undefined and probably undesirable behavior. 7312** 7313** See also: [sqlite3_blob_write()]. 7314*/ 7315int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 7316 7317/* 7318** CAPI3REF: Write Data Into A BLOB Incrementally 7319** METHOD: sqlite3_blob 7320** 7321** ^(This function is used to write data into an open [BLOB handle] from a 7322** caller-supplied buffer. N bytes of data are copied from the buffer Z 7323** into the open BLOB, starting at offset iOffset.)^ 7324** 7325** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 7326** Otherwise, an [error code] or an [extended error code] is returned.)^ 7327** ^Unless SQLITE_MISUSE is returned, this function sets the 7328** [database connection] error code and message accessible via 7329** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7330** 7331** ^If the [BLOB handle] passed as the first argument was not opened for 7332** writing (the flags parameter to [sqlite3_blob_open()] was zero), 7333** this function returns [SQLITE_READONLY]. 7334** 7335** This function may only modify the contents of the BLOB; it is 7336** not possible to increase the size of a BLOB using this API. 7337** ^If offset iOffset is less than N bytes from the end of the BLOB, 7338** [SQLITE_ERROR] is returned and no data is written. The size of the 7339** BLOB (and hence the maximum value of N+iOffset) can be determined 7340** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 7341** than zero [SQLITE_ERROR] is returned and no data is written. 7342** 7343** ^An attempt to write to an expired [BLOB handle] fails with an 7344** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 7345** before the [BLOB handle] expired are not rolled back by the 7346** expiration of the handle, though of course those changes might 7347** have been overwritten by the statement that expired the BLOB handle 7348** or by other independent statements. 7349** 7350** This routine only works on a [BLOB handle] which has been created 7351** by a prior successful call to [sqlite3_blob_open()] and which has not 7352** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7353** to this routine results in undefined and probably undesirable behavior. 7354** 7355** See also: [sqlite3_blob_read()]. 7356*/ 7357int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 7358 7359/* 7360** CAPI3REF: Virtual File System Objects 7361** 7362** A virtual filesystem (VFS) is an [sqlite3_vfs] object 7363** that SQLite uses to interact 7364** with the underlying operating system. Most SQLite builds come with a 7365** single default VFS that is appropriate for the host computer. 7366** New VFSes can be registered and existing VFSes can be unregistered. 7367** The following interfaces are provided. 7368** 7369** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 7370** ^Names are case sensitive. 7371** ^Names are zero-terminated UTF-8 strings. 7372** ^If there is no match, a NULL pointer is returned. 7373** ^If zVfsName is NULL then the default VFS is returned. 7374** 7375** ^New VFSes are registered with sqlite3_vfs_register(). 7376** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 7377** ^The same VFS can be registered multiple times without injury. 7378** ^To make an existing VFS into the default VFS, register it again 7379** with the makeDflt flag set. If two different VFSes with the 7380** same name are registered, the behavior is undefined. If a 7381** VFS is registered with a name that is NULL or an empty string, 7382** then the behavior is undefined. 7383** 7384** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 7385** ^(If the default VFS is unregistered, another VFS is chosen as 7386** the default. The choice for the new VFS is arbitrary.)^ 7387*/ 7388sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 7389int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 7390int sqlite3_vfs_unregister(sqlite3_vfs*); 7391 7392/* 7393** CAPI3REF: Mutexes 7394** 7395** The SQLite core uses these routines for thread 7396** synchronization. Though they are intended for internal 7397** use by SQLite, code that links against SQLite is 7398** permitted to use any of these routines. 7399** 7400** The SQLite source code contains multiple implementations 7401** of these mutex routines. An appropriate implementation 7402** is selected automatically at compile-time. The following 7403** implementations are available in the SQLite core: 7404** 7405** <ul> 7406** <li> SQLITE_MUTEX_PTHREADS 7407** <li> SQLITE_MUTEX_W32 7408** <li> SQLITE_MUTEX_NOOP 7409** </ul> 7410** 7411** The SQLITE_MUTEX_NOOP implementation is a set of routines 7412** that does no real locking and is appropriate for use in 7413** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 7414** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 7415** and Windows. 7416** 7417** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 7418** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 7419** implementation is included with the library. In this case the 7420** application must supply a custom mutex implementation using the 7421** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 7422** before calling sqlite3_initialize() or any other public sqlite3_ 7423** function that calls sqlite3_initialize(). 7424** 7425** ^The sqlite3_mutex_alloc() routine allocates a new 7426** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 7427** routine returns NULL if it is unable to allocate the requested 7428** mutex. The argument to sqlite3_mutex_alloc() must one of these 7429** integer constants: 7430** 7431** <ul> 7432** <li> SQLITE_MUTEX_FAST 7433** <li> SQLITE_MUTEX_RECURSIVE 7434** <li> SQLITE_MUTEX_STATIC_MAIN 7435** <li> SQLITE_MUTEX_STATIC_MEM 7436** <li> SQLITE_MUTEX_STATIC_OPEN 7437** <li> SQLITE_MUTEX_STATIC_PRNG 7438** <li> SQLITE_MUTEX_STATIC_LRU 7439** <li> SQLITE_MUTEX_STATIC_PMEM 7440** <li> SQLITE_MUTEX_STATIC_APP1 7441** <li> SQLITE_MUTEX_STATIC_APP2 7442** <li> SQLITE_MUTEX_STATIC_APP3 7443** <li> SQLITE_MUTEX_STATIC_VFS1 7444** <li> SQLITE_MUTEX_STATIC_VFS2 7445** <li> SQLITE_MUTEX_STATIC_VFS3 7446** </ul> 7447** 7448** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 7449** cause sqlite3_mutex_alloc() to create 7450** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 7451** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 7452** The mutex implementation does not need to make a distinction 7453** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 7454** not want to. SQLite will only request a recursive mutex in 7455** cases where it really needs one. If a faster non-recursive mutex 7456** implementation is available on the host platform, the mutex subsystem 7457** might return such a mutex in response to SQLITE_MUTEX_FAST. 7458** 7459** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 7460** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 7461** a pointer to a static preexisting mutex. ^Nine static mutexes are 7462** used by the current version of SQLite. Future versions of SQLite 7463** may add additional static mutexes. Static mutexes are for internal 7464** use by SQLite only. Applications that use SQLite mutexes should 7465** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 7466** SQLITE_MUTEX_RECURSIVE. 7467** 7468** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 7469** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 7470** returns a different mutex on every call. ^For the static 7471** mutex types, the same mutex is returned on every call that has 7472** the same type number. 7473** 7474** ^The sqlite3_mutex_free() routine deallocates a previously 7475** allocated dynamic mutex. Attempting to deallocate a static 7476** mutex results in undefined behavior. 7477** 7478** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 7479** to enter a mutex. ^If another thread is already within the mutex, 7480** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 7481** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 7482** upon successful entry. ^(Mutexes created using 7483** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 7484** In such cases, the 7485** mutex must be exited an equal number of times before another thread 7486** can enter.)^ If the same thread tries to enter any mutex other 7487** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 7488** 7489** ^(Some systems (for example, Windows 95) do not support the operation 7490** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 7491** will always return SQLITE_BUSY. The SQLite core only ever uses 7492** sqlite3_mutex_try() as an optimization so this is acceptable 7493** behavior.)^ 7494** 7495** ^The sqlite3_mutex_leave() routine exits a mutex that was 7496** previously entered by the same thread. The behavior 7497** is undefined if the mutex is not currently entered by the 7498** calling thread or is not currently allocated. 7499** 7500** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 7501** sqlite3_mutex_leave() is a NULL pointer, then all three routines 7502** behave as no-ops. 7503** 7504** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 7505*/ 7506sqlite3_mutex *sqlite3_mutex_alloc(int); 7507void sqlite3_mutex_free(sqlite3_mutex*); 7508void sqlite3_mutex_enter(sqlite3_mutex*); 7509int sqlite3_mutex_try(sqlite3_mutex*); 7510void sqlite3_mutex_leave(sqlite3_mutex*); 7511 7512/* 7513** CAPI3REF: Mutex Methods Object 7514** 7515** An instance of this structure defines the low-level routines 7516** used to allocate and use mutexes. 7517** 7518** Usually, the default mutex implementations provided by SQLite are 7519** sufficient, however the application has the option of substituting a custom 7520** implementation for specialized deployments or systems for which SQLite 7521** does not provide a suitable implementation. In this case, the application 7522** creates and populates an instance of this structure to pass 7523** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 7524** Additionally, an instance of this structure can be used as an 7525** output variable when querying the system for the current mutex 7526** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 7527** 7528** ^The xMutexInit method defined by this structure is invoked as 7529** part of system initialization by the sqlite3_initialize() function. 7530** ^The xMutexInit routine is called by SQLite exactly once for each 7531** effective call to [sqlite3_initialize()]. 7532** 7533** ^The xMutexEnd method defined by this structure is invoked as 7534** part of system shutdown by the sqlite3_shutdown() function. The 7535** implementation of this method is expected to release all outstanding 7536** resources obtained by the mutex methods implementation, especially 7537** those obtained by the xMutexInit method. ^The xMutexEnd() 7538** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 7539** 7540** ^(The remaining seven methods defined by this structure (xMutexAlloc, 7541** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 7542** xMutexNotheld) implement the following interfaces (respectively): 7543** 7544** <ul> 7545** <li> [sqlite3_mutex_alloc()] </li> 7546** <li> [sqlite3_mutex_free()] </li> 7547** <li> [sqlite3_mutex_enter()] </li> 7548** <li> [sqlite3_mutex_try()] </li> 7549** <li> [sqlite3_mutex_leave()] </li> 7550** <li> [sqlite3_mutex_held()] </li> 7551** <li> [sqlite3_mutex_notheld()] </li> 7552** </ul>)^ 7553** 7554** The only difference is that the public sqlite3_XXX functions enumerated 7555** above silently ignore any invocations that pass a NULL pointer instead 7556** of a valid mutex handle. The implementations of the methods defined 7557** by this structure are not required to handle this case. The results 7558** of passing a NULL pointer instead of a valid mutex handle are undefined 7559** (i.e. it is acceptable to provide an implementation that segfaults if 7560** it is passed a NULL pointer). 7561** 7562** The xMutexInit() method must be threadsafe. It must be harmless to 7563** invoke xMutexInit() multiple times within the same process and without 7564** intervening calls to xMutexEnd(). Second and subsequent calls to 7565** xMutexInit() must be no-ops. 7566** 7567** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 7568** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 7569** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 7570** memory allocation for a fast or recursive mutex. 7571** 7572** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 7573** called, but only if the prior call to xMutexInit returned SQLITE_OK. 7574** If xMutexInit fails in any way, it is expected to clean up after itself 7575** prior to returning. 7576*/ 7577typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 7578struct sqlite3_mutex_methods { 7579 int (*xMutexInit)(void); 7580 int (*xMutexEnd)(void); 7581 sqlite3_mutex *(*xMutexAlloc)(int); 7582 void (*xMutexFree)(sqlite3_mutex *); 7583 void (*xMutexEnter)(sqlite3_mutex *); 7584 int (*xMutexTry)(sqlite3_mutex *); 7585 void (*xMutexLeave)(sqlite3_mutex *); 7586 int (*xMutexHeld)(sqlite3_mutex *); 7587 int (*xMutexNotheld)(sqlite3_mutex *); 7588}; 7589 7590/* 7591** CAPI3REF: Mutex Verification Routines 7592** 7593** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 7594** are intended for use inside assert() statements. The SQLite core 7595** never uses these routines except inside an assert() and applications 7596** are advised to follow the lead of the core. The SQLite core only 7597** provides implementations for these routines when it is compiled 7598** with the SQLITE_DEBUG flag. External mutex implementations 7599** are only required to provide these routines if SQLITE_DEBUG is 7600** defined and if NDEBUG is not defined. 7601** 7602** These routines should return true if the mutex in their argument 7603** is held or not held, respectively, by the calling thread. 7604** 7605** The implementation is not required to provide versions of these 7606** routines that actually work. If the implementation does not provide working 7607** versions of these routines, it should at least provide stubs that always 7608** return true so that one does not get spurious assertion failures. 7609** 7610** If the argument to sqlite3_mutex_held() is a NULL pointer then 7611** the routine should return 1. This seems counter-intuitive since 7612** clearly the mutex cannot be held if it does not exist. But 7613** the reason the mutex does not exist is because the build is not 7614** using mutexes. And we do not want the assert() containing the 7615** call to sqlite3_mutex_held() to fail, so a non-zero return is 7616** the appropriate thing to do. The sqlite3_mutex_notheld() 7617** interface should also return 1 when given a NULL pointer. 7618*/ 7619#ifndef NDEBUG 7620int sqlite3_mutex_held(sqlite3_mutex*); 7621int sqlite3_mutex_notheld(sqlite3_mutex*); 7622#endif 7623 7624/* 7625** CAPI3REF: Mutex Types 7626** 7627** The [sqlite3_mutex_alloc()] interface takes a single argument 7628** which is one of these integer constants. 7629** 7630** The set of static mutexes may change from one SQLite release to the 7631** next. Applications that override the built-in mutex logic must be 7632** prepared to accommodate additional static mutexes. 7633*/ 7634#define SQLITE_MUTEX_FAST 0 7635#define SQLITE_MUTEX_RECURSIVE 1 7636#define SQLITE_MUTEX_STATIC_MAIN 2 7637#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 7638#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 7639#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 7640#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 7641#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 7642#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 7643#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 7644#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 7645#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 7646#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 7647#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 7648#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 7649#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 7650 7651/* Legacy compatibility: */ 7652#define SQLITE_MUTEX_STATIC_MASTER 2 7653 7654 7655/* 7656** CAPI3REF: Retrieve the mutex for a database connection 7657** METHOD: sqlite3 7658** 7659** ^This interface returns a pointer the [sqlite3_mutex] object that 7660** serializes access to the [database connection] given in the argument 7661** when the [threading mode] is Serialized. 7662** ^If the [threading mode] is Single-thread or Multi-thread then this 7663** routine returns a NULL pointer. 7664*/ 7665sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 7666 7667/* 7668** CAPI3REF: Low-Level Control Of Database Files 7669** METHOD: sqlite3 7670** KEYWORDS: {file control} 7671** 7672** ^The [sqlite3_file_control()] interface makes a direct call to the 7673** xFileControl method for the [sqlite3_io_methods] object associated 7674** with a particular database identified by the second argument. ^The 7675** name of the database is "main" for the main database or "temp" for the 7676** TEMP database, or the name that appears after the AS keyword for 7677** databases that are added using the [ATTACH] SQL command. 7678** ^A NULL pointer can be used in place of "main" to refer to the 7679** main database file. 7680** ^The third and fourth parameters to this routine 7681** are passed directly through to the second and third parameters of 7682** the xFileControl method. ^The return value of the xFileControl 7683** method becomes the return value of this routine. 7684** 7685** A few opcodes for [sqlite3_file_control()] are handled directly 7686** by the SQLite core and never invoke the 7687** sqlite3_io_methods.xFileControl method. 7688** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 7689** a pointer to the underlying [sqlite3_file] object to be written into 7690** the space pointed to by the 4th parameter. The 7691** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns 7692** the [sqlite3_file] object associated with the journal file instead of 7693** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns 7694** a pointer to the underlying [sqlite3_vfs] object for the file. 7695** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter 7696** from the pager. 7697** 7698** ^If the second parameter (zDbName) does not match the name of any 7699** open database file, then SQLITE_ERROR is returned. ^This error 7700** code is not remembered and will not be recalled by [sqlite3_errcode()] 7701** or [sqlite3_errmsg()]. The underlying xFileControl method might 7702** also return SQLITE_ERROR. There is no way to distinguish between 7703** an incorrect zDbName and an SQLITE_ERROR return from the underlying 7704** xFileControl method. 7705** 7706** See also: [file control opcodes] 7707*/ 7708int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 7709 7710/* 7711** CAPI3REF: Testing Interface 7712** 7713** ^The sqlite3_test_control() interface is used to read out internal 7714** state of SQLite and to inject faults into SQLite for testing 7715** purposes. ^The first parameter is an operation code that determines 7716** the number, meaning, and operation of all subsequent parameters. 7717** 7718** This interface is not for use by applications. It exists solely 7719** for verifying the correct operation of the SQLite library. Depending 7720** on how the SQLite library is compiled, this interface might not exist. 7721** 7722** The details of the operation codes, their meanings, the parameters 7723** they take, and what they do are all subject to change without notice. 7724** Unlike most of the SQLite API, this function is not guaranteed to 7725** operate consistently from one release to the next. 7726*/ 7727int sqlite3_test_control(int op, ...); 7728 7729/* 7730** CAPI3REF: Testing Interface Operation Codes 7731** 7732** These constants are the valid operation code parameters used 7733** as the first argument to [sqlite3_test_control()]. 7734** 7735** These parameters and their meanings are subject to change 7736** without notice. These values are for testing purposes only. 7737** Applications should not use any of these parameters or the 7738** [sqlite3_test_control()] interface. 7739*/ 7740#define SQLITE_TESTCTRL_FIRST 5 7741#define SQLITE_TESTCTRL_PRNG_SAVE 5 7742#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7743#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */ 7744#define SQLITE_TESTCTRL_BITVEC_TEST 8 7745#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7746#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7747#define SQLITE_TESTCTRL_PENDING_BYTE 11 7748#define SQLITE_TESTCTRL_ASSERT 12 7749#define SQLITE_TESTCTRL_ALWAYS 13 7750#define SQLITE_TESTCTRL_RESERVE 14 /* NOT USED */ 7751#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7752#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */ 7753#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7754#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17 7755#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7756#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7757#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7758#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7759#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7760#define SQLITE_TESTCTRL_BYTEORDER 22 7761#define SQLITE_TESTCTRL_ISINIT 23 7762#define SQLITE_TESTCTRL_SORTER_MMAP 24 7763#define SQLITE_TESTCTRL_IMPOSTER 25 7764#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7765#define SQLITE_TESTCTRL_RESULT_INTREAL 27 7766#define SQLITE_TESTCTRL_PRNG_SEED 28 7767#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29 7768#define SQLITE_TESTCTRL_SEEK_COUNT 30 7769#define SQLITE_TESTCTRL_TRACEFLAGS 31 7770#define SQLITE_TESTCTRL_LAST 31 /* Largest TESTCTRL */ 7771 7772/* 7773** CAPI3REF: SQL Keyword Checking 7774** 7775** These routines provide access to the set of SQL language keywords 7776** recognized by SQLite. Applications can uses these routines to determine 7777** whether or not a specific identifier needs to be escaped (for example, 7778** by enclosing in double-quotes) so as not to confuse the parser. 7779** 7780** The sqlite3_keyword_count() interface returns the number of distinct 7781** keywords understood by SQLite. 7782** 7783** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and 7784** makes *Z point to that keyword expressed as UTF8 and writes the number 7785** of bytes in the keyword into *L. The string that *Z points to is not 7786** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns 7787** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z 7788** or L are NULL or invalid pointers then calls to 7789** sqlite3_keyword_name(N,Z,L) result in undefined behavior. 7790** 7791** The sqlite3_keyword_check(Z,L) interface checks to see whether or not 7792** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero 7793** if it is and zero if not. 7794** 7795** The parser used by SQLite is forgiving. It is often possible to use 7796** a keyword as an identifier as long as such use does not result in a 7797** parsing ambiguity. For example, the statement 7798** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and 7799** creates a new table named "BEGIN" with three columns named 7800** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid 7801** using keywords as identifiers. Common techniques used to avoid keyword 7802** name collisions include: 7803** <ul> 7804** <li> Put all identifier names inside double-quotes. This is the official 7805** SQL way to escape identifier names. 7806** <li> Put identifier names inside [...]. This is not standard SQL, 7807** but it is what SQL Server does and so lots of programmers use this 7808** technique. 7809** <li> Begin every identifier with the letter "Z" as no SQL keywords start 7810** with "Z". 7811** <li> Include a digit somewhere in every identifier name. 7812** </ul> 7813** 7814** Note that the number of keywords understood by SQLite can depend on 7815** compile-time options. For example, "VACUUM" is not a keyword if 7816** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also, 7817** new keywords may be added to future releases of SQLite. 7818*/ 7819int sqlite3_keyword_count(void); 7820int sqlite3_keyword_name(int,const char**,int*); 7821int sqlite3_keyword_check(const char*,int); 7822 7823/* 7824** CAPI3REF: Dynamic String Object 7825** KEYWORDS: {dynamic string} 7826** 7827** An instance of the sqlite3_str object contains a dynamically-sized 7828** string under construction. 7829** 7830** The lifecycle of an sqlite3_str object is as follows: 7831** <ol> 7832** <li> ^The sqlite3_str object is created using [sqlite3_str_new()]. 7833** <li> ^Text is appended to the sqlite3_str object using various 7834** methods, such as [sqlite3_str_appendf()]. 7835** <li> ^The sqlite3_str object is destroyed and the string it created 7836** is returned using the [sqlite3_str_finish()] interface. 7837** </ol> 7838*/ 7839typedef struct sqlite3_str sqlite3_str; 7840 7841/* 7842** CAPI3REF: Create A New Dynamic String Object 7843** CONSTRUCTOR: sqlite3_str 7844** 7845** ^The [sqlite3_str_new(D)] interface allocates and initializes 7846** a new [sqlite3_str] object. To avoid memory leaks, the object returned by 7847** [sqlite3_str_new()] must be freed by a subsequent call to 7848** [sqlite3_str_finish(X)]. 7849** 7850** ^The [sqlite3_str_new(D)] interface always returns a pointer to a 7851** valid [sqlite3_str] object, though in the event of an out-of-memory 7852** error the returned object might be a special singleton that will 7853** silently reject new text, always return SQLITE_NOMEM from 7854** [sqlite3_str_errcode()], always return 0 for 7855** [sqlite3_str_length()], and always return NULL from 7856** [sqlite3_str_finish(X)]. It is always safe to use the value 7857** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter 7858** to any of the other [sqlite3_str] methods. 7859** 7860** The D parameter to [sqlite3_str_new(D)] may be NULL. If the 7861** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum 7862** length of the string contained in the [sqlite3_str] object will be 7863** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead 7864** of [SQLITE_MAX_LENGTH]. 7865*/ 7866sqlite3_str *sqlite3_str_new(sqlite3*); 7867 7868/* 7869** CAPI3REF: Finalize A Dynamic String 7870** DESTRUCTOR: sqlite3_str 7871** 7872** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X 7873** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()] 7874** that contains the constructed string. The calling application should 7875** pass the returned value to [sqlite3_free()] to avoid a memory leak. 7876** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any 7877** errors were encountered during construction of the string. ^The 7878** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the 7879** string in [sqlite3_str] object X is zero bytes long. 7880*/ 7881char *sqlite3_str_finish(sqlite3_str*); 7882 7883/* 7884** CAPI3REF: Add Content To A Dynamic String 7885** METHOD: sqlite3_str 7886** 7887** These interfaces add content to an sqlite3_str object previously obtained 7888** from [sqlite3_str_new()]. 7889** 7890** ^The [sqlite3_str_appendf(X,F,...)] and 7891** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf] 7892** functionality of SQLite to append formatted text onto the end of 7893** [sqlite3_str] object X. 7894** 7895** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S 7896** onto the end of the [sqlite3_str] object X. N must be non-negative. 7897** S must contain at least N non-zero bytes of content. To append a 7898** zero-terminated string in its entirety, use the [sqlite3_str_appendall()] 7899** method instead. 7900** 7901** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of 7902** zero-terminated string S onto the end of [sqlite3_str] object X. 7903** 7904** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the 7905** single-byte character C onto the end of [sqlite3_str] object X. 7906** ^This method can be used, for example, to add whitespace indentation. 7907** 7908** ^The [sqlite3_str_reset(X)] method resets the string under construction 7909** inside [sqlite3_str] object X back to zero bytes in length. 7910** 7911** These methods do not return a result code. ^If an error occurs, that fact 7912** is recorded in the [sqlite3_str] object and can be recovered by a 7913** subsequent call to [sqlite3_str_errcode(X)]. 7914*/ 7915void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...); 7916void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list); 7917void sqlite3_str_append(sqlite3_str*, const char *zIn, int N); 7918void sqlite3_str_appendall(sqlite3_str*, const char *zIn); 7919void sqlite3_str_appendchar(sqlite3_str*, int N, char C); 7920void sqlite3_str_reset(sqlite3_str*); 7921 7922/* 7923** CAPI3REF: Status Of A Dynamic String 7924** METHOD: sqlite3_str 7925** 7926** These interfaces return the current status of an [sqlite3_str] object. 7927** 7928** ^If any prior errors have occurred while constructing the dynamic string 7929** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return 7930** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns 7931** [SQLITE_NOMEM] following any out-of-memory error, or 7932** [SQLITE_TOOBIG] if the size of the dynamic string exceeds 7933** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors. 7934** 7935** ^The [sqlite3_str_length(X)] method returns the current length, in bytes, 7936** of the dynamic string under construction in [sqlite3_str] object X. 7937** ^The length returned by [sqlite3_str_length(X)] does not include the 7938** zero-termination byte. 7939** 7940** ^The [sqlite3_str_value(X)] method returns a pointer to the current 7941** content of the dynamic string under construction in X. The value 7942** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X 7943** and might be freed or altered by any subsequent method on the same 7944** [sqlite3_str] object. Applications must not used the pointer returned 7945** [sqlite3_str_value(X)] after any subsequent method call on the same 7946** object. ^Applications may change the content of the string returned 7947** by [sqlite3_str_value(X)] as long as they do not write into any bytes 7948** outside the range of 0 to [sqlite3_str_length(X)] and do not read or 7949** write any byte after any subsequent sqlite3_str method call. 7950*/ 7951int sqlite3_str_errcode(sqlite3_str*); 7952int sqlite3_str_length(sqlite3_str*); 7953char *sqlite3_str_value(sqlite3_str*); 7954 7955/* 7956** CAPI3REF: SQLite Runtime Status 7957** 7958** ^These interfaces are used to retrieve runtime status information 7959** about the performance of SQLite, and optionally to reset various 7960** highwater marks. ^The first argument is an integer code for 7961** the specific parameter to measure. ^(Recognized integer codes 7962** are of the form [status parameters | SQLITE_STATUS_...].)^ 7963** ^The current value of the parameter is returned into *pCurrent. 7964** ^The highest recorded value is returned in *pHighwater. ^If the 7965** resetFlag is true, then the highest record value is reset after 7966** *pHighwater is written. ^(Some parameters do not record the highest 7967** value. For those parameters 7968** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7969** ^(Other parameters record only the highwater mark and not the current 7970** value. For these latter parameters nothing is written into *pCurrent.)^ 7971** 7972** ^The sqlite3_status() and sqlite3_status64() routines return 7973** SQLITE_OK on success and a non-zero [error code] on failure. 7974** 7975** If either the current value or the highwater mark is too large to 7976** be represented by a 32-bit integer, then the values returned by 7977** sqlite3_status() are undefined. 7978** 7979** See also: [sqlite3_db_status()] 7980*/ 7981int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7982int sqlite3_status64( 7983 int op, 7984 sqlite3_int64 *pCurrent, 7985 sqlite3_int64 *pHighwater, 7986 int resetFlag 7987); 7988 7989 7990/* 7991** CAPI3REF: Status Parameters 7992** KEYWORDS: {status parameters} 7993** 7994** These integer constants designate various run-time status parameters 7995** that can be returned by [sqlite3_status()]. 7996** 7997** <dl> 7998** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7999** <dd>This parameter is the current amount of memory checked out 8000** using [sqlite3_malloc()], either directly or indirectly. The 8001** figure includes calls made to [sqlite3_malloc()] by the application 8002** and internal memory usage by the SQLite library. Auxiliary page-cache 8003** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 8004** this parameter. The amount returned is the sum of the allocation 8005** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 8006** 8007** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 8008** <dd>This parameter records the largest memory allocation request 8009** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 8010** internal equivalents). Only the value returned in the 8011** *pHighwater parameter to [sqlite3_status()] is of interest. 8012** The value written into the *pCurrent parameter is undefined.</dd>)^ 8013** 8014** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 8015** <dd>This parameter records the number of separate memory allocations 8016** currently checked out.</dd>)^ 8017** 8018** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 8019** <dd>This parameter returns the number of pages used out of the 8020** [pagecache memory allocator] that was configured using 8021** [SQLITE_CONFIG_PAGECACHE]. The 8022** value returned is in pages, not in bytes.</dd>)^ 8023** 8024** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 8025** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 8026** <dd>This parameter returns the number of bytes of page cache 8027** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 8028** buffer and where forced to overflow to [sqlite3_malloc()]. The 8029** returned value includes allocations that overflowed because they 8030** where too large (they were larger than the "sz" parameter to 8031** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 8032** no space was left in the page cache.</dd>)^ 8033** 8034** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 8035** <dd>This parameter records the largest memory allocation request 8036** handed to the [pagecache memory allocator]. Only the value returned in the 8037** *pHighwater parameter to [sqlite3_status()] is of interest. 8038** The value written into the *pCurrent parameter is undefined.</dd>)^ 8039** 8040** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 8041** <dd>No longer used.</dd> 8042** 8043** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 8044** <dd>No longer used.</dd> 8045** 8046** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 8047** <dd>No longer used.</dd> 8048** 8049** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 8050** <dd>The *pHighwater parameter records the deepest parser stack. 8051** The *pCurrent value is undefined. The *pHighwater value is only 8052** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 8053** </dl> 8054** 8055** New status parameters may be added from time to time. 8056*/ 8057#define SQLITE_STATUS_MEMORY_USED 0 8058#define SQLITE_STATUS_PAGECACHE_USED 1 8059#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 8060#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 8061#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 8062#define SQLITE_STATUS_MALLOC_SIZE 5 8063#define SQLITE_STATUS_PARSER_STACK 6 8064#define SQLITE_STATUS_PAGECACHE_SIZE 7 8065#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 8066#define SQLITE_STATUS_MALLOC_COUNT 9 8067 8068/* 8069** CAPI3REF: Database Connection Status 8070** METHOD: sqlite3 8071** 8072** ^This interface is used to retrieve runtime status information 8073** about a single [database connection]. ^The first argument is the 8074** database connection object to be interrogated. ^The second argument 8075** is an integer constant, taken from the set of 8076** [SQLITE_DBSTATUS options], that 8077** determines the parameter to interrogate. The set of 8078** [SQLITE_DBSTATUS options] is likely 8079** to grow in future releases of SQLite. 8080** 8081** ^The current value of the requested parameter is written into *pCur 8082** and the highest instantaneous value is written into *pHiwtr. ^If 8083** the resetFlg is true, then the highest instantaneous value is 8084** reset back down to the current value. 8085** 8086** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 8087** non-zero [error code] on failure. 8088** 8089** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 8090*/ 8091int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 8092 8093/* 8094** CAPI3REF: Status Parameters for database connections 8095** KEYWORDS: {SQLITE_DBSTATUS options} 8096** 8097** These constants are the available integer "verbs" that can be passed as 8098** the second argument to the [sqlite3_db_status()] interface. 8099** 8100** New verbs may be added in future releases of SQLite. Existing verbs 8101** might be discontinued. Applications should check the return code from 8102** [sqlite3_db_status()] to make sure that the call worked. 8103** The [sqlite3_db_status()] interface will return a non-zero error code 8104** if a discontinued or unsupported verb is invoked. 8105** 8106** <dl> 8107** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 8108** <dd>This parameter returns the number of lookaside memory slots currently 8109** checked out.</dd>)^ 8110** 8111** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 8112** <dd>This parameter returns the number of malloc attempts that were 8113** satisfied using lookaside memory. Only the high-water value is meaningful; 8114** the current value is always zero.)^ 8115** 8116** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 8117** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 8118** <dd>This parameter returns the number malloc attempts that might have 8119** been satisfied using lookaside memory but failed due to the amount of 8120** memory requested being larger than the lookaside slot size. 8121** Only the high-water value is meaningful; 8122** the current value is always zero.)^ 8123** 8124** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 8125** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 8126** <dd>This parameter returns the number malloc attempts that might have 8127** been satisfied using lookaside memory but failed due to all lookaside 8128** memory already being in use. 8129** Only the high-water value is meaningful; 8130** the current value is always zero.)^ 8131** 8132** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 8133** <dd>This parameter returns the approximate number of bytes of heap 8134** memory used by all pager caches associated with the database connection.)^ 8135** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 8136** 8137** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 8138** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 8139** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 8140** pager cache is shared between two or more connections the bytes of heap 8141** memory used by that pager cache is divided evenly between the attached 8142** connections.)^ In other words, if none of the pager caches associated 8143** with the database connection are shared, this request returns the same 8144** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 8145** shared, the value returned by this call will be smaller than that returned 8146** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 8147** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 8148** 8149** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 8150** <dd>This parameter returns the approximate number of bytes of heap 8151** memory used to store the schema for all databases associated 8152** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 8153** ^The full amount of memory used by the schemas is reported, even if the 8154** schema memory is shared with other database connections due to 8155** [shared cache mode] being enabled. 8156** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 8157** 8158** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 8159** <dd>This parameter returns the approximate number of bytes of heap 8160** and lookaside memory used by all prepared statements associated with 8161** the database connection.)^ 8162** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 8163** </dd> 8164** 8165** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 8166** <dd>This parameter returns the number of pager cache hits that have 8167** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 8168** is always 0. 8169** </dd> 8170** 8171** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 8172** <dd>This parameter returns the number of pager cache misses that have 8173** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 8174** is always 0. 8175** </dd> 8176** 8177** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 8178** <dd>This parameter returns the number of dirty cache entries that have 8179** been written to disk. Specifically, the number of pages written to the 8180** wal file in wal mode databases, or the number of pages written to the 8181** database file in rollback mode databases. Any pages written as part of 8182** transaction rollback or database recovery operations are not included. 8183** If an IO or other error occurs while writing a page to disk, the effect 8184** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 8185** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 8186** </dd> 8187** 8188** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 8189** <dd>This parameter returns the number of dirty cache entries that have 8190** been written to disk in the middle of a transaction due to the page 8191** cache overflowing. Transactions are more efficient if they are written 8192** to disk all at once. When pages spill mid-transaction, that introduces 8193** additional overhead. This parameter can be used help identify 8194** inefficiencies that can be resolved by increasing the cache size. 8195** </dd> 8196** 8197** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 8198** <dd>This parameter returns zero for the current value if and only if 8199** all foreign key constraints (deferred or immediate) have been 8200** resolved.)^ ^The highwater mark is always 0. 8201** </dd> 8202** </dl> 8203*/ 8204#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 8205#define SQLITE_DBSTATUS_CACHE_USED 1 8206#define SQLITE_DBSTATUS_SCHEMA_USED 2 8207#define SQLITE_DBSTATUS_STMT_USED 3 8208#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 8209#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 8210#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 8211#define SQLITE_DBSTATUS_CACHE_HIT 7 8212#define SQLITE_DBSTATUS_CACHE_MISS 8 8213#define SQLITE_DBSTATUS_CACHE_WRITE 9 8214#define SQLITE_DBSTATUS_DEFERRED_FKS 10 8215#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 8216#define SQLITE_DBSTATUS_CACHE_SPILL 12 8217#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 8218 8219 8220/* 8221** CAPI3REF: Prepared Statement Status 8222** METHOD: sqlite3_stmt 8223** 8224** ^(Each prepared statement maintains various 8225** [SQLITE_STMTSTATUS counters] that measure the number 8226** of times it has performed specific operations.)^ These counters can 8227** be used to monitor the performance characteristics of the prepared 8228** statements. For example, if the number of table steps greatly exceeds 8229** the number of table searches or result rows, that would tend to indicate 8230** that the prepared statement is using a full table scan rather than 8231** an index. 8232** 8233** ^(This interface is used to retrieve and reset counter values from 8234** a [prepared statement]. The first argument is the prepared statement 8235** object to be interrogated. The second argument 8236** is an integer code for a specific [SQLITE_STMTSTATUS counter] 8237** to be interrogated.)^ 8238** ^The current value of the requested counter is returned. 8239** ^If the resetFlg is true, then the counter is reset to zero after this 8240** interface call returns. 8241** 8242** See also: [sqlite3_status()] and [sqlite3_db_status()]. 8243*/ 8244int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 8245 8246/* 8247** CAPI3REF: Status Parameters for prepared statements 8248** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 8249** 8250** These preprocessor macros define integer codes that name counter 8251** values associated with the [sqlite3_stmt_status()] interface. 8252** The meanings of the various counters are as follows: 8253** 8254** <dl> 8255** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 8256** <dd>^This is the number of times that SQLite has stepped forward in 8257** a table as part of a full table scan. Large numbers for this counter 8258** may indicate opportunities for performance improvement through 8259** careful use of indices.</dd> 8260** 8261** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 8262** <dd>^This is the number of sort operations that have occurred. 8263** A non-zero value in this counter may indicate an opportunity to 8264** improvement performance through careful use of indices.</dd> 8265** 8266** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 8267** <dd>^This is the number of rows inserted into transient indices that 8268** were created automatically in order to help joins run faster. 8269** A non-zero value in this counter may indicate an opportunity to 8270** improvement performance by adding permanent indices that do not 8271** need to be reinitialized each time the statement is run.</dd> 8272** 8273** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 8274** <dd>^This is the number of virtual machine operations executed 8275** by the prepared statement if that number is less than or equal 8276** to 2147483647. The number of virtual machine operations can be 8277** used as a proxy for the total work done by the prepared statement. 8278** If the number of virtual machine operations exceeds 2147483647 8279** then the value returned by this statement status code is undefined. 8280** 8281** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 8282** <dd>^This is the number of times that the prepare statement has been 8283** automatically regenerated due to schema changes or changes to 8284** [bound parameters] that might affect the query plan. 8285** 8286** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 8287** <dd>^This is the number of times that the prepared statement has 8288** been run. A single "run" for the purposes of this counter is one 8289** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 8290** The counter is incremented on the first [sqlite3_step()] call of each 8291** cycle. 8292** 8293** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 8294** <dd>^This is the approximate number of bytes of heap memory 8295** used to store the prepared statement. ^This value is not actually 8296** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 8297** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 8298** </dd> 8299** </dl> 8300*/ 8301#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 8302#define SQLITE_STMTSTATUS_SORT 2 8303#define SQLITE_STMTSTATUS_AUTOINDEX 3 8304#define SQLITE_STMTSTATUS_VM_STEP 4 8305#define SQLITE_STMTSTATUS_REPREPARE 5 8306#define SQLITE_STMTSTATUS_RUN 6 8307#define SQLITE_STMTSTATUS_MEMUSED 99 8308 8309/* 8310** CAPI3REF: Custom Page Cache Object 8311** 8312** The sqlite3_pcache type is opaque. It is implemented by 8313** the pluggable module. The SQLite core has no knowledge of 8314** its size or internal structure and never deals with the 8315** sqlite3_pcache object except by holding and passing pointers 8316** to the object. 8317** 8318** See [sqlite3_pcache_methods2] for additional information. 8319*/ 8320typedef struct sqlite3_pcache sqlite3_pcache; 8321 8322/* 8323** CAPI3REF: Custom Page Cache Object 8324** 8325** The sqlite3_pcache_page object represents a single page in the 8326** page cache. The page cache will allocate instances of this 8327** object. Various methods of the page cache use pointers to instances 8328** of this object as parameters or as their return value. 8329** 8330** See [sqlite3_pcache_methods2] for additional information. 8331*/ 8332typedef struct sqlite3_pcache_page sqlite3_pcache_page; 8333struct sqlite3_pcache_page { 8334 void *pBuf; /* The content of the page */ 8335 void *pExtra; /* Extra information associated with the page */ 8336}; 8337 8338/* 8339** CAPI3REF: Application Defined Page Cache. 8340** KEYWORDS: {page cache} 8341** 8342** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 8343** register an alternative page cache implementation by passing in an 8344** instance of the sqlite3_pcache_methods2 structure.)^ 8345** In many applications, most of the heap memory allocated by 8346** SQLite is used for the page cache. 8347** By implementing a 8348** custom page cache using this API, an application can better control 8349** the amount of memory consumed by SQLite, the way in which 8350** that memory is allocated and released, and the policies used to 8351** determine exactly which parts of a database file are cached and for 8352** how long. 8353** 8354** The alternative page cache mechanism is an 8355** extreme measure that is only needed by the most demanding applications. 8356** The built-in page cache is recommended for most uses. 8357** 8358** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 8359** internal buffer by SQLite within the call to [sqlite3_config]. Hence 8360** the application may discard the parameter after the call to 8361** [sqlite3_config()] returns.)^ 8362** 8363** [[the xInit() page cache method]] 8364** ^(The xInit() method is called once for each effective 8365** call to [sqlite3_initialize()])^ 8366** (usually only once during the lifetime of the process). ^(The xInit() 8367** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 8368** The intent of the xInit() method is to set up global data structures 8369** required by the custom page cache implementation. 8370** ^(If the xInit() method is NULL, then the 8371** built-in default page cache is used instead of the application defined 8372** page cache.)^ 8373** 8374** [[the xShutdown() page cache method]] 8375** ^The xShutdown() method is called by [sqlite3_shutdown()]. 8376** It can be used to clean up 8377** any outstanding resources before process shutdown, if required. 8378** ^The xShutdown() method may be NULL. 8379** 8380** ^SQLite automatically serializes calls to the xInit method, 8381** so the xInit method need not be threadsafe. ^The 8382** xShutdown method is only called from [sqlite3_shutdown()] so it does 8383** not need to be threadsafe either. All other methods must be threadsafe 8384** in multithreaded applications. 8385** 8386** ^SQLite will never invoke xInit() more than once without an intervening 8387** call to xShutdown(). 8388** 8389** [[the xCreate() page cache methods]] 8390** ^SQLite invokes the xCreate() method to construct a new cache instance. 8391** SQLite will typically create one cache instance for each open database file, 8392** though this is not guaranteed. ^The 8393** first parameter, szPage, is the size in bytes of the pages that must 8394** be allocated by the cache. ^szPage will always a power of two. ^The 8395** second parameter szExtra is a number of bytes of extra storage 8396** associated with each page cache entry. ^The szExtra parameter will 8397** a number less than 250. SQLite will use the 8398** extra szExtra bytes on each page to store metadata about the underlying 8399** database page on disk. The value passed into szExtra depends 8400** on the SQLite version, the target platform, and how SQLite was compiled. 8401** ^The third argument to xCreate(), bPurgeable, is true if the cache being 8402** created will be used to cache database pages of a file stored on disk, or 8403** false if it is used for an in-memory database. The cache implementation 8404** does not have to do anything special based with the value of bPurgeable; 8405** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 8406** never invoke xUnpin() except to deliberately delete a page. 8407** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 8408** false will always have the "discard" flag set to true. 8409** ^Hence, a cache created with bPurgeable false will 8410** never contain any unpinned pages. 8411** 8412** [[the xCachesize() page cache method]] 8413** ^(The xCachesize() method may be called at any time by SQLite to set the 8414** suggested maximum cache-size (number of pages stored by) the cache 8415** instance passed as the first argument. This is the value configured using 8416** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 8417** parameter, the implementation is not required to do anything with this 8418** value; it is advisory only. 8419** 8420** [[the xPagecount() page cache methods]] 8421** The xPagecount() method must return the number of pages currently 8422** stored in the cache, both pinned and unpinned. 8423** 8424** [[the xFetch() page cache methods]] 8425** The xFetch() method locates a page in the cache and returns a pointer to 8426** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 8427** The pBuf element of the returned sqlite3_pcache_page object will be a 8428** pointer to a buffer of szPage bytes used to store the content of a 8429** single database page. The pExtra element of sqlite3_pcache_page will be 8430** a pointer to the szExtra bytes of extra storage that SQLite has requested 8431** for each entry in the page cache. 8432** 8433** The page to be fetched is determined by the key. ^The minimum key value 8434** is 1. After it has been retrieved using xFetch, the page is considered 8435** to be "pinned". 8436** 8437** If the requested page is already in the page cache, then the page cache 8438** implementation must return a pointer to the page buffer with its content 8439** intact. If the requested page is not already in the cache, then the 8440** cache implementation should use the value of the createFlag 8441** parameter to help it determined what action to take: 8442** 8443** <table border=1 width=85% align=center> 8444** <tr><th> createFlag <th> Behavior when page is not already in cache 8445** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 8446** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 8447** Otherwise return NULL. 8448** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 8449** NULL if allocating a new page is effectively impossible. 8450** </table> 8451** 8452** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 8453** will only use a createFlag of 2 after a prior call with a createFlag of 1 8454** failed.)^ In between the xFetch() calls, SQLite may 8455** attempt to unpin one or more cache pages by spilling the content of 8456** pinned pages to disk and synching the operating system disk cache. 8457** 8458** [[the xUnpin() page cache method]] 8459** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 8460** as its second argument. If the third parameter, discard, is non-zero, 8461** then the page must be evicted from the cache. 8462** ^If the discard parameter is 8463** zero, then the page may be discarded or retained at the discretion of 8464** page cache implementation. ^The page cache implementation 8465** may choose to evict unpinned pages at any time. 8466** 8467** The cache must not perform any reference counting. A single 8468** call to xUnpin() unpins the page regardless of the number of prior calls 8469** to xFetch(). 8470** 8471** [[the xRekey() page cache methods]] 8472** The xRekey() method is used to change the key value associated with the 8473** page passed as the second argument. If the cache 8474** previously contains an entry associated with newKey, it must be 8475** discarded. ^Any prior cache entry associated with newKey is guaranteed not 8476** to be pinned. 8477** 8478** When SQLite calls the xTruncate() method, the cache must discard all 8479** existing cache entries with page numbers (keys) greater than or equal 8480** to the value of the iLimit parameter passed to xTruncate(). If any 8481** of these pages are pinned, they are implicitly unpinned, meaning that 8482** they can be safely discarded. 8483** 8484** [[the xDestroy() page cache method]] 8485** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 8486** All resources associated with the specified cache should be freed. ^After 8487** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 8488** handle invalid, and will not use it with any other sqlite3_pcache_methods2 8489** functions. 8490** 8491** [[the xShrink() page cache method]] 8492** ^SQLite invokes the xShrink() method when it wants the page cache to 8493** free up as much of heap memory as possible. The page cache implementation 8494** is not obligated to free any memory, but well-behaved implementations should 8495** do their best. 8496*/ 8497typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 8498struct sqlite3_pcache_methods2 { 8499 int iVersion; 8500 void *pArg; 8501 int (*xInit)(void*); 8502 void (*xShutdown)(void*); 8503 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 8504 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8505 int (*xPagecount)(sqlite3_pcache*); 8506 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8507 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 8508 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 8509 unsigned oldKey, unsigned newKey); 8510 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8511 void (*xDestroy)(sqlite3_pcache*); 8512 void (*xShrink)(sqlite3_pcache*); 8513}; 8514 8515/* 8516** This is the obsolete pcache_methods object that has now been replaced 8517** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 8518** retained in the header file for backwards compatibility only. 8519*/ 8520typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 8521struct sqlite3_pcache_methods { 8522 void *pArg; 8523 int (*xInit)(void*); 8524 void (*xShutdown)(void*); 8525 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 8526 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8527 int (*xPagecount)(sqlite3_pcache*); 8528 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8529 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 8530 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 8531 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8532 void (*xDestroy)(sqlite3_pcache*); 8533}; 8534 8535 8536/* 8537** CAPI3REF: Online Backup Object 8538** 8539** The sqlite3_backup object records state information about an ongoing 8540** online backup operation. ^The sqlite3_backup object is created by 8541** a call to [sqlite3_backup_init()] and is destroyed by a call to 8542** [sqlite3_backup_finish()]. 8543** 8544** See Also: [Using the SQLite Online Backup API] 8545*/ 8546typedef struct sqlite3_backup sqlite3_backup; 8547 8548/* 8549** CAPI3REF: Online Backup API. 8550** 8551** The backup API copies the content of one database into another. 8552** It is useful either for creating backups of databases or 8553** for copying in-memory databases to or from persistent files. 8554** 8555** See Also: [Using the SQLite Online Backup API] 8556** 8557** ^SQLite holds a write transaction open on the destination database file 8558** for the duration of the backup operation. 8559** ^The source database is read-locked only while it is being read; 8560** it is not locked continuously for the entire backup operation. 8561** ^Thus, the backup may be performed on a live source database without 8562** preventing other database connections from 8563** reading or writing to the source database while the backup is underway. 8564** 8565** ^(To perform a backup operation: 8566** <ol> 8567** <li><b>sqlite3_backup_init()</b> is called once to initialize the 8568** backup, 8569** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 8570** the data between the two databases, and finally 8571** <li><b>sqlite3_backup_finish()</b> is called to release all resources 8572** associated with the backup operation. 8573** </ol>)^ 8574** There should be exactly one call to sqlite3_backup_finish() for each 8575** successful call to sqlite3_backup_init(). 8576** 8577** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 8578** 8579** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 8580** [database connection] associated with the destination database 8581** and the database name, respectively. 8582** ^The database name is "main" for the main database, "temp" for the 8583** temporary database, or the name specified after the AS keyword in 8584** an [ATTACH] statement for an attached database. 8585** ^The S and M arguments passed to 8586** sqlite3_backup_init(D,N,S,M) identify the [database connection] 8587** and database name of the source database, respectively. 8588** ^The source and destination [database connections] (parameters S and D) 8589** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 8590** an error. 8591** 8592** ^A call to sqlite3_backup_init() will fail, returning NULL, if 8593** there is already a read or read-write transaction open on the 8594** destination database. 8595** 8596** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 8597** returned and an error code and error message are stored in the 8598** destination [database connection] D. 8599** ^The error code and message for the failed call to sqlite3_backup_init() 8600** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 8601** [sqlite3_errmsg16()] functions. 8602** ^A successful call to sqlite3_backup_init() returns a pointer to an 8603** [sqlite3_backup] object. 8604** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 8605** sqlite3_backup_finish() functions to perform the specified backup 8606** operation. 8607** 8608** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 8609** 8610** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 8611** the source and destination databases specified by [sqlite3_backup] object B. 8612** ^If N is negative, all remaining source pages are copied. 8613** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 8614** are still more pages to be copied, then the function returns [SQLITE_OK]. 8615** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 8616** from source to destination, then it returns [SQLITE_DONE]. 8617** ^If an error occurs while running sqlite3_backup_step(B,N), 8618** then an [error code] is returned. ^As well as [SQLITE_OK] and 8619** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 8620** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 8621** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 8622** 8623** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 8624** <ol> 8625** <li> the destination database was opened read-only, or 8626** <li> the destination database is using write-ahead-log journaling 8627** and the destination and source page sizes differ, or 8628** <li> the destination database is an in-memory database and the 8629** destination and source page sizes differ. 8630** </ol>)^ 8631** 8632** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 8633** the [sqlite3_busy_handler | busy-handler function] 8634** is invoked (if one is specified). ^If the 8635** busy-handler returns non-zero before the lock is available, then 8636** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 8637** sqlite3_backup_step() can be retried later. ^If the source 8638** [database connection] 8639** is being used to write to the source database when sqlite3_backup_step() 8640** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 8641** case the call to sqlite3_backup_step() can be retried later on. ^(If 8642** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 8643** [SQLITE_READONLY] is returned, then 8644** there is no point in retrying the call to sqlite3_backup_step(). These 8645** errors are considered fatal.)^ The application must accept 8646** that the backup operation has failed and pass the backup operation handle 8647** to the sqlite3_backup_finish() to release associated resources. 8648** 8649** ^The first call to sqlite3_backup_step() obtains an exclusive lock 8650** on the destination file. ^The exclusive lock is not released until either 8651** sqlite3_backup_finish() is called or the backup operation is complete 8652** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 8653** sqlite3_backup_step() obtains a [shared lock] on the source database that 8654** lasts for the duration of the sqlite3_backup_step() call. 8655** ^Because the source database is not locked between calls to 8656** sqlite3_backup_step(), the source database may be modified mid-way 8657** through the backup process. ^If the source database is modified by an 8658** external process or via a database connection other than the one being 8659** used by the backup operation, then the backup will be automatically 8660** restarted by the next call to sqlite3_backup_step(). ^If the source 8661** database is modified by the using the same database connection as is used 8662** by the backup operation, then the backup database is automatically 8663** updated at the same time. 8664** 8665** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 8666** 8667** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 8668** application wishes to abandon the backup operation, the application 8669** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 8670** ^The sqlite3_backup_finish() interfaces releases all 8671** resources associated with the [sqlite3_backup] object. 8672** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 8673** active write-transaction on the destination database is rolled back. 8674** The [sqlite3_backup] object is invalid 8675** and may not be used following a call to sqlite3_backup_finish(). 8676** 8677** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 8678** sqlite3_backup_step() errors occurred, regardless or whether or not 8679** sqlite3_backup_step() completed. 8680** ^If an out-of-memory condition or IO error occurred during any prior 8681** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 8682** sqlite3_backup_finish() returns the corresponding [error code]. 8683** 8684** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 8685** is not a permanent error and does not affect the return value of 8686** sqlite3_backup_finish(). 8687** 8688** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 8689** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 8690** 8691** ^The sqlite3_backup_remaining() routine returns the number of pages still 8692** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 8693** ^The sqlite3_backup_pagecount() routine returns the total number of pages 8694** in the source database at the conclusion of the most recent 8695** sqlite3_backup_step(). 8696** ^(The values returned by these functions are only updated by 8697** sqlite3_backup_step(). If the source database is modified in a way that 8698** changes the size of the source database or the number of pages remaining, 8699** those changes are not reflected in the output of sqlite3_backup_pagecount() 8700** and sqlite3_backup_remaining() until after the next 8701** sqlite3_backup_step().)^ 8702** 8703** <b>Concurrent Usage of Database Handles</b> 8704** 8705** ^The source [database connection] may be used by the application for other 8706** purposes while a backup operation is underway or being initialized. 8707** ^If SQLite is compiled and configured to support threadsafe database 8708** connections, then the source database connection may be used concurrently 8709** from within other threads. 8710** 8711** However, the application must guarantee that the destination 8712** [database connection] is not passed to any other API (by any thread) after 8713** sqlite3_backup_init() is called and before the corresponding call to 8714** sqlite3_backup_finish(). SQLite does not currently check to see 8715** if the application incorrectly accesses the destination [database connection] 8716** and so no error code is reported, but the operations may malfunction 8717** nevertheless. Use of the destination database connection while a 8718** backup is in progress might also also cause a mutex deadlock. 8719** 8720** If running in [shared cache mode], the application must 8721** guarantee that the shared cache used by the destination database 8722** is not accessed while the backup is running. In practice this means 8723** that the application must guarantee that the disk file being 8724** backed up to is not accessed by any connection within the process, 8725** not just the specific connection that was passed to sqlite3_backup_init(). 8726** 8727** The [sqlite3_backup] object itself is partially threadsafe. Multiple 8728** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 8729** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 8730** APIs are not strictly speaking threadsafe. If they are invoked at the 8731** same time as another thread is invoking sqlite3_backup_step() it is 8732** possible that they return invalid values. 8733*/ 8734sqlite3_backup *sqlite3_backup_init( 8735 sqlite3 *pDest, /* Destination database handle */ 8736 const char *zDestName, /* Destination database name */ 8737 sqlite3 *pSource, /* Source database handle */ 8738 const char *zSourceName /* Source database name */ 8739); 8740int sqlite3_backup_step(sqlite3_backup *p, int nPage); 8741int sqlite3_backup_finish(sqlite3_backup *p); 8742int sqlite3_backup_remaining(sqlite3_backup *p); 8743int sqlite3_backup_pagecount(sqlite3_backup *p); 8744 8745/* 8746** CAPI3REF: Unlock Notification 8747** METHOD: sqlite3 8748** 8749** ^When running in shared-cache mode, a database operation may fail with 8750** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 8751** individual tables within the shared-cache cannot be obtained. See 8752** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 8753** ^This API may be used to register a callback that SQLite will invoke 8754** when the connection currently holding the required lock relinquishes it. 8755** ^This API is only available if the library was compiled with the 8756** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 8757** 8758** See Also: [Using the SQLite Unlock Notification Feature]. 8759** 8760** ^Shared-cache locks are released when a database connection concludes 8761** its current transaction, either by committing it or rolling it back. 8762** 8763** ^When a connection (known as the blocked connection) fails to obtain a 8764** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 8765** identity of the database connection (the blocking connection) that 8766** has locked the required resource is stored internally. ^After an 8767** application receives an SQLITE_LOCKED error, it may call the 8768** sqlite3_unlock_notify() method with the blocked connection handle as 8769** the first argument to register for a callback that will be invoked 8770** when the blocking connections current transaction is concluded. ^The 8771** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 8772** call that concludes the blocking connection's transaction. 8773** 8774** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 8775** there is a chance that the blocking connection will have already 8776** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 8777** If this happens, then the specified callback is invoked immediately, 8778** from within the call to sqlite3_unlock_notify().)^ 8779** 8780** ^If the blocked connection is attempting to obtain a write-lock on a 8781** shared-cache table, and more than one other connection currently holds 8782** a read-lock on the same table, then SQLite arbitrarily selects one of 8783** the other connections to use as the blocking connection. 8784** 8785** ^(There may be at most one unlock-notify callback registered by a 8786** blocked connection. If sqlite3_unlock_notify() is called when the 8787** blocked connection already has a registered unlock-notify callback, 8788** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 8789** called with a NULL pointer as its second argument, then any existing 8790** unlock-notify callback is canceled. ^The blocked connections 8791** unlock-notify callback may also be canceled by closing the blocked 8792** connection using [sqlite3_close()]. 8793** 8794** The unlock-notify callback is not reentrant. If an application invokes 8795** any sqlite3_xxx API functions from within an unlock-notify callback, a 8796** crash or deadlock may be the result. 8797** 8798** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 8799** returns SQLITE_OK. 8800** 8801** <b>Callback Invocation Details</b> 8802** 8803** When an unlock-notify callback is registered, the application provides a 8804** single void* pointer that is passed to the callback when it is invoked. 8805** However, the signature of the callback function allows SQLite to pass 8806** it an array of void* context pointers. The first argument passed to 8807** an unlock-notify callback is a pointer to an array of void* pointers, 8808** and the second is the number of entries in the array. 8809** 8810** When a blocking connection's transaction is concluded, there may be 8811** more than one blocked connection that has registered for an unlock-notify 8812** callback. ^If two or more such blocked connections have specified the 8813** same callback function, then instead of invoking the callback function 8814** multiple times, it is invoked once with the set of void* context pointers 8815** specified by the blocked connections bundled together into an array. 8816** This gives the application an opportunity to prioritize any actions 8817** related to the set of unblocked database connections. 8818** 8819** <b>Deadlock Detection</b> 8820** 8821** Assuming that after registering for an unlock-notify callback a 8822** database waits for the callback to be issued before taking any further 8823** action (a reasonable assumption), then using this API may cause the 8824** application to deadlock. For example, if connection X is waiting for 8825** connection Y's transaction to be concluded, and similarly connection 8826** Y is waiting on connection X's transaction, then neither connection 8827** will proceed and the system may remain deadlocked indefinitely. 8828** 8829** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 8830** detection. ^If a given call to sqlite3_unlock_notify() would put the 8831** system in a deadlocked state, then SQLITE_LOCKED is returned and no 8832** unlock-notify callback is registered. The system is said to be in 8833** a deadlocked state if connection A has registered for an unlock-notify 8834** callback on the conclusion of connection B's transaction, and connection 8835** B has itself registered for an unlock-notify callback when connection 8836** A's transaction is concluded. ^Indirect deadlock is also detected, so 8837** the system is also considered to be deadlocked if connection B has 8838** registered for an unlock-notify callback on the conclusion of connection 8839** C's transaction, where connection C is waiting on connection A. ^Any 8840** number of levels of indirection are allowed. 8841** 8842** <b>The "DROP TABLE" Exception</b> 8843** 8844** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 8845** always appropriate to call sqlite3_unlock_notify(). There is however, 8846** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 8847** SQLite checks if there are any currently executing SELECT statements 8848** that belong to the same connection. If there are, SQLITE_LOCKED is 8849** returned. In this case there is no "blocking connection", so invoking 8850** sqlite3_unlock_notify() results in the unlock-notify callback being 8851** invoked immediately. If the application then re-attempts the "DROP TABLE" 8852** or "DROP INDEX" query, an infinite loop might be the result. 8853** 8854** One way around this problem is to check the extended error code returned 8855** by an sqlite3_step() call. ^(If there is a blocking connection, then the 8856** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 8857** the special "DROP TABLE/INDEX" case, the extended error code is just 8858** SQLITE_LOCKED.)^ 8859*/ 8860int sqlite3_unlock_notify( 8861 sqlite3 *pBlocked, /* Waiting connection */ 8862 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 8863 void *pNotifyArg /* Argument to pass to xNotify */ 8864); 8865 8866 8867/* 8868** CAPI3REF: String Comparison 8869** 8870** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 8871** and extensions to compare the contents of two buffers containing UTF-8 8872** strings in a case-independent fashion, using the same definition of "case 8873** independence" that SQLite uses internally when comparing identifiers. 8874*/ 8875int sqlite3_stricmp(const char *, const char *); 8876int sqlite3_strnicmp(const char *, const char *, int); 8877 8878/* 8879** CAPI3REF: String Globbing 8880* 8881** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 8882** string X matches the [GLOB] pattern P. 8883** ^The definition of [GLOB] pattern matching used in 8884** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 8885** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 8886** is case sensitive. 8887** 8888** Note that this routine returns zero on a match and non-zero if the strings 8889** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8890** 8891** See also: [sqlite3_strlike()]. 8892*/ 8893int sqlite3_strglob(const char *zGlob, const char *zStr); 8894 8895/* 8896** CAPI3REF: String LIKE Matching 8897* 8898** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 8899** string X matches the [LIKE] pattern P with escape character E. 8900** ^The definition of [LIKE] pattern matching used in 8901** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 8902** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 8903** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 8904** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 8905** insensitive - equivalent upper and lower case ASCII characters match 8906** one another. 8907** 8908** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 8909** only ASCII characters are case folded. 8910** 8911** Note that this routine returns zero on a match and non-zero if the strings 8912** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8913** 8914** See also: [sqlite3_strglob()]. 8915*/ 8916int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8917 8918/* 8919** CAPI3REF: Error Logging Interface 8920** 8921** ^The [sqlite3_log()] interface writes a message into the [error log] 8922** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8923** ^If logging is enabled, the zFormat string and subsequent arguments are 8924** used with [sqlite3_snprintf()] to generate the final output string. 8925** 8926** The sqlite3_log() interface is intended for use by extensions such as 8927** virtual tables, collating functions, and SQL functions. While there is 8928** nothing to prevent an application from calling sqlite3_log(), doing so 8929** is considered bad form. 8930** 8931** The zFormat string must not be NULL. 8932** 8933** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8934** will not use dynamically allocated memory. The log message is stored in 8935** a fixed-length buffer on the stack. If the log message is longer than 8936** a few hundred characters, it will be truncated to the length of the 8937** buffer. 8938*/ 8939void sqlite3_log(int iErrCode, const char *zFormat, ...); 8940 8941/* 8942** CAPI3REF: Write-Ahead Log Commit Hook 8943** METHOD: sqlite3 8944** 8945** ^The [sqlite3_wal_hook()] function is used to register a callback that 8946** is invoked each time data is committed to a database in wal mode. 8947** 8948** ^(The callback is invoked by SQLite after the commit has taken place and 8949** the associated write-lock on the database released)^, so the implementation 8950** may read, write or [checkpoint] the database as required. 8951** 8952** ^The first parameter passed to the callback function when it is invoked 8953** is a copy of the third parameter passed to sqlite3_wal_hook() when 8954** registering the callback. ^The second is a copy of the database handle. 8955** ^The third parameter is the name of the database that was written to - 8956** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8957** is the number of pages currently in the write-ahead log file, 8958** including those that were just committed. 8959** 8960** The callback function should normally return [SQLITE_OK]. ^If an error 8961** code is returned, that error will propagate back up through the 8962** SQLite code base to cause the statement that provoked the callback 8963** to report an error, though the commit will have still occurred. If the 8964** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8965** that does not correspond to any valid SQLite error code, the results 8966** are undefined. 8967** 8968** A single database handle may have at most a single write-ahead log callback 8969** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8970** previously registered write-ahead log callback. ^Note that the 8971** [sqlite3_wal_autocheckpoint()] interface and the 8972** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8973** overwrite any prior [sqlite3_wal_hook()] settings. 8974*/ 8975void *sqlite3_wal_hook( 8976 sqlite3*, 8977 int(*)(void *,sqlite3*,const char*,int), 8978 void* 8979); 8980 8981/* 8982** CAPI3REF: Configure an auto-checkpoint 8983** METHOD: sqlite3 8984** 8985** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8986** [sqlite3_wal_hook()] that causes any database on [database connection] D 8987** to automatically [checkpoint] 8988** after committing a transaction if there are N or 8989** more frames in the [write-ahead log] file. ^Passing zero or 8990** a negative value as the nFrame parameter disables automatic 8991** checkpoints entirely. 8992** 8993** ^The callback registered by this function replaces any existing callback 8994** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8995** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8996** configured by this function. 8997** 8998** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8999** from SQL. 9000** 9001** ^Checkpoints initiated by this mechanism are 9002** [sqlite3_wal_checkpoint_v2|PASSIVE]. 9003** 9004** ^Every new [database connection] defaults to having the auto-checkpoint 9005** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 9006** pages. The use of this interface 9007** is only necessary if the default setting is found to be suboptimal 9008** for a particular application. 9009*/ 9010int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 9011 9012/* 9013** CAPI3REF: Checkpoint a database 9014** METHOD: sqlite3 9015** 9016** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 9017** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 9018** 9019** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 9020** [write-ahead log] for database X on [database connection] D to be 9021** transferred into the database file and for the write-ahead log to 9022** be reset. See the [checkpointing] documentation for addition 9023** information. 9024** 9025** This interface used to be the only way to cause a checkpoint to 9026** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 9027** interface was added. This interface is retained for backwards 9028** compatibility and as a convenience for applications that need to manually 9029** start a callback but which do not need the full power (and corresponding 9030** complication) of [sqlite3_wal_checkpoint_v2()]. 9031*/ 9032int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 9033 9034/* 9035** CAPI3REF: Checkpoint a database 9036** METHOD: sqlite3 9037** 9038** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 9039** operation on database X of [database connection] D in mode M. Status 9040** information is written back into integers pointed to by L and C.)^ 9041** ^(The M parameter must be a valid [checkpoint mode]:)^ 9042** 9043** <dl> 9044** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 9045** ^Checkpoint as many frames as possible without waiting for any database 9046** readers or writers to finish, then sync the database file if all frames 9047** in the log were checkpointed. ^The [busy-handler callback] 9048** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 9049** ^On the other hand, passive mode might leave the checkpoint unfinished 9050** if there are concurrent readers or writers. 9051** 9052** <dt>SQLITE_CHECKPOINT_FULL<dd> 9053** ^This mode blocks (it invokes the 9054** [sqlite3_busy_handler|busy-handler callback]) until there is no 9055** database writer and all readers are reading from the most recent database 9056** snapshot. ^It then checkpoints all frames in the log file and syncs the 9057** database file. ^This mode blocks new database writers while it is pending, 9058** but new database readers are allowed to continue unimpeded. 9059** 9060** <dt>SQLITE_CHECKPOINT_RESTART<dd> 9061** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 9062** that after checkpointing the log file it blocks (calls the 9063** [busy-handler callback]) 9064** until all readers are reading from the database file only. ^This ensures 9065** that the next writer will restart the log file from the beginning. 9066** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 9067** database writer attempts while it is pending, but does not impede readers. 9068** 9069** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 9070** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 9071** addition that it also truncates the log file to zero bytes just prior 9072** to a successful return. 9073** </dl> 9074** 9075** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 9076** the log file or to -1 if the checkpoint could not run because 9077** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 9078** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 9079** log file (including any that were already checkpointed before the function 9080** was called) or to -1 if the checkpoint could not run due to an error or 9081** because the database is not in WAL mode. ^Note that upon successful 9082** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 9083** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 9084** 9085** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 9086** any other process is running a checkpoint operation at the same time, the 9087** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 9088** busy-handler configured, it will not be invoked in this case. 9089** 9090** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 9091** exclusive "writer" lock on the database file. ^If the writer lock cannot be 9092** obtained immediately, and a busy-handler is configured, it is invoked and 9093** the writer lock retried until either the busy-handler returns 0 or the lock 9094** is successfully obtained. ^The busy-handler is also invoked while waiting for 9095** database readers as described above. ^If the busy-handler returns 0 before 9096** the writer lock is obtained or while waiting for database readers, the 9097** checkpoint operation proceeds from that point in the same way as 9098** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 9099** without blocking any further. ^SQLITE_BUSY is returned in this case. 9100** 9101** ^If parameter zDb is NULL or points to a zero length string, then the 9102** specified operation is attempted on all WAL databases [attached] to 9103** [database connection] db. In this case the 9104** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 9105** an SQLITE_BUSY error is encountered when processing one or more of the 9106** attached WAL databases, the operation is still attempted on any remaining 9107** attached databases and SQLITE_BUSY is returned at the end. ^If any other 9108** error occurs while processing an attached database, processing is abandoned 9109** and the error code is returned to the caller immediately. ^If no error 9110** (SQLITE_BUSY or otherwise) is encountered while processing the attached 9111** databases, SQLITE_OK is returned. 9112** 9113** ^If database zDb is the name of an attached database that is not in WAL 9114** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 9115** zDb is not NULL (or a zero length string) and is not the name of any 9116** attached database, SQLITE_ERROR is returned to the caller. 9117** 9118** ^Unless it returns SQLITE_MISUSE, 9119** the sqlite3_wal_checkpoint_v2() interface 9120** sets the error information that is queried by 9121** [sqlite3_errcode()] and [sqlite3_errmsg()]. 9122** 9123** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 9124** from SQL. 9125*/ 9126int sqlite3_wal_checkpoint_v2( 9127 sqlite3 *db, /* Database handle */ 9128 const char *zDb, /* Name of attached database (or NULL) */ 9129 int eMode, /* SQLITE_CHECKPOINT_* value */ 9130 int *pnLog, /* OUT: Size of WAL log in frames */ 9131 int *pnCkpt /* OUT: Total number of frames checkpointed */ 9132); 9133 9134/* 9135** CAPI3REF: Checkpoint Mode Values 9136** KEYWORDS: {checkpoint mode} 9137** 9138** These constants define all valid values for the "checkpoint mode" passed 9139** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 9140** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 9141** meaning of each of these checkpoint modes. 9142*/ 9143#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 9144#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 9145#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 9146#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 9147 9148/* 9149** CAPI3REF: Virtual Table Interface Configuration 9150** 9151** This function may be called by either the [xConnect] or [xCreate] method 9152** of a [virtual table] implementation to configure 9153** various facets of the virtual table interface. 9154** 9155** If this interface is invoked outside the context of an xConnect or 9156** xCreate virtual table method then the behavior is undefined. 9157** 9158** In the call sqlite3_vtab_config(D,C,...) the D parameter is the 9159** [database connection] in which the virtual table is being created and 9160** which is passed in as the first argument to the [xConnect] or [xCreate] 9161** method that is invoking sqlite3_vtab_config(). The C parameter is one 9162** of the [virtual table configuration options]. The presence and meaning 9163** of parameters after C depend on which [virtual table configuration option] 9164** is used. 9165*/ 9166int sqlite3_vtab_config(sqlite3*, int op, ...); 9167 9168/* 9169** CAPI3REF: Virtual Table Configuration Options 9170** KEYWORDS: {virtual table configuration options} 9171** KEYWORDS: {virtual table configuration option} 9172** 9173** These macros define the various options to the 9174** [sqlite3_vtab_config()] interface that [virtual table] implementations 9175** can use to customize and optimize their behavior. 9176** 9177** <dl> 9178** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]] 9179** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt> 9180** <dd>Calls of the form 9181** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 9182** where X is an integer. If X is zero, then the [virtual table] whose 9183** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 9184** support constraints. In this configuration (which is the default) if 9185** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 9186** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 9187** specified as part of the users SQL statement, regardless of the actual 9188** ON CONFLICT mode specified. 9189** 9190** If X is non-zero, then the virtual table implementation guarantees 9191** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 9192** any modifications to internal or persistent data structures have been made. 9193** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 9194** is able to roll back a statement or database transaction, and abandon 9195** or continue processing the current SQL statement as appropriate. 9196** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 9197** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 9198** had been ABORT. 9199** 9200** Virtual table implementations that are required to handle OR REPLACE 9201** must do so within the [xUpdate] method. If a call to the 9202** [sqlite3_vtab_on_conflict()] function indicates that the current ON 9203** CONFLICT policy is REPLACE, the virtual table implementation should 9204** silently replace the appropriate rows within the xUpdate callback and 9205** return SQLITE_OK. Or, if this is not possible, it may return 9206** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 9207** constraint handling. 9208** </dd> 9209** 9210** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt> 9211** <dd>Calls of the form 9212** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the 9213** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9214** prohibits that virtual table from being used from within triggers and 9215** views. 9216** </dd> 9217** 9218** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt> 9219** <dd>Calls of the form 9220** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the 9221** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9222** identify that virtual table as being safe to use from within triggers 9223** and views. Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the 9224** virtual table can do no serious harm even if it is controlled by a 9225** malicious hacker. Developers should avoid setting the SQLITE_VTAB_INNOCUOUS 9226** flag unless absolutely necessary. 9227** </dd> 9228** </dl> 9229*/ 9230#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 9231#define SQLITE_VTAB_INNOCUOUS 2 9232#define SQLITE_VTAB_DIRECTONLY 3 9233 9234/* 9235** CAPI3REF: Determine The Virtual Table Conflict Policy 9236** 9237** This function may only be called from within a call to the [xUpdate] method 9238** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 9239** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 9240** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 9241** of the SQL statement that triggered the call to the [xUpdate] method of the 9242** [virtual table]. 9243*/ 9244int sqlite3_vtab_on_conflict(sqlite3 *); 9245 9246/* 9247** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 9248** 9249** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 9250** method of a [virtual table], then it might return true if the 9251** column is being fetched as part of an UPDATE operation during which the 9252** column value will not change. The virtual table implementation can use 9253** this hint as permission to substitute a return value that is less 9254** expensive to compute and that the corresponding 9255** [xUpdate] method understands as a "no-change" value. 9256** 9257** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 9258** the column is not changed by the UPDATE statement, then the xColumn 9259** method can optionally return without setting a result, without calling 9260** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 9261** In that case, [sqlite3_value_nochange(X)] will return true for the 9262** same column in the [xUpdate] method. 9263** 9264** The sqlite3_vtab_nochange() routine is an optimization. Virtual table 9265** implementations should continue to give a correct answer even if the 9266** sqlite3_vtab_nochange() interface were to always return false. In the 9267** current implementation, the sqlite3_vtab_nochange() interface does always 9268** returns false for the enhanced [UPDATE FROM] statement. 9269*/ 9270int sqlite3_vtab_nochange(sqlite3_context*); 9271 9272/* 9273** CAPI3REF: Determine The Collation For a Virtual Table Constraint 9274** 9275** This function may only be called from within a call to the [xBestIndex] 9276** method of a [virtual table]. 9277** 9278** The first argument must be the sqlite3_index_info object that is the 9279** first parameter to the xBestIndex() method. The second argument must be 9280** an index into the aConstraint[] array belonging to the sqlite3_index_info 9281** structure passed to xBestIndex. This function returns a pointer to a buffer 9282** containing the name of the collation sequence for the corresponding 9283** constraint. 9284*/ 9285SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 9286 9287/* 9288** CAPI3REF: Conflict resolution modes 9289** KEYWORDS: {conflict resolution mode} 9290** 9291** These constants are returned by [sqlite3_vtab_on_conflict()] to 9292** inform a [virtual table] implementation what the [ON CONFLICT] mode 9293** is for the SQL statement being evaluated. 9294** 9295** Note that the [SQLITE_IGNORE] constant is also used as a potential 9296** return value from the [sqlite3_set_authorizer()] callback and that 9297** [SQLITE_ABORT] is also a [result code]. 9298*/ 9299#define SQLITE_ROLLBACK 1 9300/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 9301#define SQLITE_FAIL 3 9302/* #define SQLITE_ABORT 4 // Also an error code */ 9303#define SQLITE_REPLACE 5 9304 9305/* 9306** CAPI3REF: Prepared Statement Scan Status Opcodes 9307** KEYWORDS: {scanstatus options} 9308** 9309** The following constants can be used for the T parameter to the 9310** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 9311** different metric for sqlite3_stmt_scanstatus() to return. 9312** 9313** When the value returned to V is a string, space to hold that string is 9314** managed by the prepared statement S and will be automatically freed when 9315** S is finalized. 9316** 9317** <dl> 9318** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 9319** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be 9320** set to the total number of times that the X-th loop has run.</dd> 9321** 9322** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 9323** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set 9324** to the total number of rows examined by all iterations of the X-th loop.</dd> 9325** 9326** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 9327** <dd>^The "double" variable pointed to by the V parameter will be set to the 9328** query planner's estimate for the average number of rows output from each 9329** iteration of the X-th loop. If the query planner's estimates was accurate, 9330** then this value will approximate the quotient NVISIT/NLOOP and the 9331** product of this value for all prior loops with the same SELECTID will 9332** be the NLOOP value for the current loop. 9333** 9334** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 9335** <dd>^The "const char *" variable pointed to by the V parameter will be set 9336** to a zero-terminated UTF-8 string containing the name of the index or table 9337** used for the X-th loop. 9338** 9339** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 9340** <dd>^The "const char *" variable pointed to by the V parameter will be set 9341** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 9342** description for the X-th loop. 9343** 9344** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 9345** <dd>^The "int" variable pointed to by the V parameter will be set to the 9346** "select-id" for the X-th loop. The select-id identifies which query or 9347** subquery the loop is part of. The main query has a select-id of zero. 9348** The select-id is the same value as is output in the first column 9349** of an [EXPLAIN QUERY PLAN] query. 9350** </dl> 9351*/ 9352#define SQLITE_SCANSTAT_NLOOP 0 9353#define SQLITE_SCANSTAT_NVISIT 1 9354#define SQLITE_SCANSTAT_EST 2 9355#define SQLITE_SCANSTAT_NAME 3 9356#define SQLITE_SCANSTAT_EXPLAIN 4 9357#define SQLITE_SCANSTAT_SELECTID 5 9358 9359/* 9360** CAPI3REF: Prepared Statement Scan Status 9361** METHOD: sqlite3_stmt 9362** 9363** This interface returns information about the predicted and measured 9364** performance for pStmt. Advanced applications can use this 9365** interface to compare the predicted and the measured performance and 9366** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 9367** 9368** Since this interface is expected to be rarely used, it is only 9369** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 9370** compile-time option. 9371** 9372** The "iScanStatusOp" parameter determines which status information to return. 9373** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 9374** of this interface is undefined. 9375** ^The requested measurement is written into a variable pointed to by 9376** the "pOut" parameter. 9377** Parameter "idx" identifies the specific loop to retrieve statistics for. 9378** Loops are numbered starting from zero. ^If idx is out of range - less than 9379** zero or greater than or equal to the total number of loops used to implement 9380** the statement - a non-zero value is returned and the variable that pOut 9381** points to is unchanged. 9382** 9383** ^Statistics might not be available for all loops in all statements. ^In cases 9384** where there exist loops with no available statistics, this function behaves 9385** as if the loop did not exist - it returns non-zero and leave the variable 9386** that pOut points to unchanged. 9387** 9388** See also: [sqlite3_stmt_scanstatus_reset()] 9389*/ 9390int sqlite3_stmt_scanstatus( 9391 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 9392 int idx, /* Index of loop to report on */ 9393 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 9394 void *pOut /* Result written here */ 9395); 9396 9397/* 9398** CAPI3REF: Zero Scan-Status Counters 9399** METHOD: sqlite3_stmt 9400** 9401** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 9402** 9403** This API is only available if the library is built with pre-processor 9404** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 9405*/ 9406void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 9407 9408/* 9409** CAPI3REF: Flush caches to disk mid-transaction 9410** METHOD: sqlite3 9411** 9412** ^If a write-transaction is open on [database connection] D when the 9413** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 9414** pages in the pager-cache that are not currently in use are written out 9415** to disk. A dirty page may be in use if a database cursor created by an 9416** active SQL statement is reading from it, or if it is page 1 of a database 9417** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 9418** interface flushes caches for all schemas - "main", "temp", and 9419** any [attached] databases. 9420** 9421** ^If this function needs to obtain extra database locks before dirty pages 9422** can be flushed to disk, it does so. ^If those locks cannot be obtained 9423** immediately and there is a busy-handler callback configured, it is invoked 9424** in the usual manner. ^If the required lock still cannot be obtained, then 9425** the database is skipped and an attempt made to flush any dirty pages 9426** belonging to the next (if any) database. ^If any databases are skipped 9427** because locks cannot be obtained, but no other error occurs, this 9428** function returns SQLITE_BUSY. 9429** 9430** ^If any other error occurs while flushing dirty pages to disk (for 9431** example an IO error or out-of-memory condition), then processing is 9432** abandoned and an SQLite [error code] is returned to the caller immediately. 9433** 9434** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 9435** 9436** ^This function does not set the database handle error code or message 9437** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 9438*/ 9439int sqlite3_db_cacheflush(sqlite3*); 9440 9441/* 9442** CAPI3REF: The pre-update hook. 9443** METHOD: sqlite3 9444** 9445** ^These interfaces are only available if SQLite is compiled using the 9446** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 9447** 9448** ^The [sqlite3_preupdate_hook()] interface registers a callback function 9449** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 9450** on a database table. 9451** ^At most one preupdate hook may be registered at a time on a single 9452** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 9453** the previous setting. 9454** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 9455** with a NULL pointer as the second parameter. 9456** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 9457** the first parameter to callbacks. 9458** 9459** ^The preupdate hook only fires for changes to real database tables; the 9460** preupdate hook is not invoked for changes to [virtual tables] or to 9461** system tables like sqlite_sequence or sqlite_stat1. 9462** 9463** ^The second parameter to the preupdate callback is a pointer to 9464** the [database connection] that registered the preupdate hook. 9465** ^The third parameter to the preupdate callback is one of the constants 9466** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 9467** kind of update operation that is about to occur. 9468** ^(The fourth parameter to the preupdate callback is the name of the 9469** database within the database connection that is being modified. This 9470** will be "main" for the main database or "temp" for TEMP tables or 9471** the name given after the AS keyword in the [ATTACH] statement for attached 9472** databases.)^ 9473** ^The fifth parameter to the preupdate callback is the name of the 9474** table that is being modified. 9475** 9476** For an UPDATE or DELETE operation on a [rowid table], the sixth 9477** parameter passed to the preupdate callback is the initial [rowid] of the 9478** row being modified or deleted. For an INSERT operation on a rowid table, 9479** or any operation on a WITHOUT ROWID table, the value of the sixth 9480** parameter is undefined. For an INSERT or UPDATE on a rowid table the 9481** seventh parameter is the final rowid value of the row being inserted 9482** or updated. The value of the seventh parameter passed to the callback 9483** function is not defined for operations on WITHOUT ROWID tables, or for 9484** DELETE operations on rowid tables. 9485** 9486** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 9487** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 9488** provide additional information about a preupdate event. These routines 9489** may only be called from within a preupdate callback. Invoking any of 9490** these routines from outside of a preupdate callback or with a 9491** [database connection] pointer that is different from the one supplied 9492** to the preupdate callback results in undefined and probably undesirable 9493** behavior. 9494** 9495** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 9496** in the row that is being inserted, updated, or deleted. 9497** 9498** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 9499** a [protected sqlite3_value] that contains the value of the Nth column of 9500** the table row before it is updated. The N parameter must be between 0 9501** and one less than the number of columns or the behavior will be 9502** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 9503** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 9504** behavior is undefined. The [sqlite3_value] that P points to 9505** will be destroyed when the preupdate callback returns. 9506** 9507** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 9508** a [protected sqlite3_value] that contains the value of the Nth column of 9509** the table row after it is updated. The N parameter must be between 0 9510** and one less than the number of columns or the behavior will be 9511** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 9512** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 9513** behavior is undefined. The [sqlite3_value] that P points to 9514** will be destroyed when the preupdate callback returns. 9515** 9516** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 9517** callback was invoked as a result of a direct insert, update, or delete 9518** operation; or 1 for inserts, updates, or deletes invoked by top-level 9519** triggers; or 2 for changes resulting from triggers called by top-level 9520** triggers; and so forth. 9521** 9522** See also: [sqlite3_update_hook()] 9523*/ 9524#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 9525void *sqlite3_preupdate_hook( 9526 sqlite3 *db, 9527 void(*xPreUpdate)( 9528 void *pCtx, /* Copy of third arg to preupdate_hook() */ 9529 sqlite3 *db, /* Database handle */ 9530 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 9531 char const *zDb, /* Database name */ 9532 char const *zName, /* Table name */ 9533 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 9534 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 9535 ), 9536 void* 9537); 9538int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 9539int sqlite3_preupdate_count(sqlite3 *); 9540int sqlite3_preupdate_depth(sqlite3 *); 9541int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 9542#endif 9543 9544/* 9545** CAPI3REF: Low-level system error code 9546** METHOD: sqlite3 9547** 9548** ^Attempt to return the underlying operating system error code or error 9549** number that caused the most recent I/O error or failure to open a file. 9550** The return value is OS-dependent. For example, on unix systems, after 9551** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 9552** called to get back the underlying "errno" that caused the problem, such 9553** as ENOSPC, EAUTH, EISDIR, and so forth. 9554*/ 9555int sqlite3_system_errno(sqlite3*); 9556 9557/* 9558** CAPI3REF: Database Snapshot 9559** KEYWORDS: {snapshot} {sqlite3_snapshot} 9560** 9561** An instance of the snapshot object records the state of a [WAL mode] 9562** database for some specific point in history. 9563** 9564** In [WAL mode], multiple [database connections] that are open on the 9565** same database file can each be reading a different historical version 9566** of the database file. When a [database connection] begins a read 9567** transaction, that connection sees an unchanging copy of the database 9568** as it existed for the point in time when the transaction first started. 9569** Subsequent changes to the database from other connections are not seen 9570** by the reader until a new read transaction is started. 9571** 9572** The sqlite3_snapshot object records state information about an historical 9573** version of the database file so that it is possible to later open a new read 9574** transaction that sees that historical version of the database rather than 9575** the most recent version. 9576*/ 9577typedef struct sqlite3_snapshot { 9578 unsigned char hidden[48]; 9579} sqlite3_snapshot; 9580 9581/* 9582** CAPI3REF: Record A Database Snapshot 9583** CONSTRUCTOR: sqlite3_snapshot 9584** 9585** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 9586** new [sqlite3_snapshot] object that records the current state of 9587** schema S in database connection D. ^On success, the 9588** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 9589** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 9590** If there is not already a read-transaction open on schema S when 9591** this function is called, one is opened automatically. 9592** 9593** The following must be true for this function to succeed. If any of 9594** the following statements are false when sqlite3_snapshot_get() is 9595** called, SQLITE_ERROR is returned. The final value of *P is undefined 9596** in this case. 9597** 9598** <ul> 9599** <li> The database handle must not be in [autocommit mode]. 9600** 9601** <li> Schema S of [database connection] D must be a [WAL mode] database. 9602** 9603** <li> There must not be a write transaction open on schema S of database 9604** connection D. 9605** 9606** <li> One or more transactions must have been written to the current wal 9607** file since it was created on disk (by any connection). This means 9608** that a snapshot cannot be taken on a wal mode database with no wal 9609** file immediately after it is first opened. At least one transaction 9610** must be written to it first. 9611** </ul> 9612** 9613** This function may also return SQLITE_NOMEM. If it is called with the 9614** database handle in autocommit mode but fails for some other reason, 9615** whether or not a read transaction is opened on schema S is undefined. 9616** 9617** The [sqlite3_snapshot] object returned from a successful call to 9618** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 9619** to avoid a memory leak. 9620** 9621** The [sqlite3_snapshot_get()] interface is only available when the 9622** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9623*/ 9624SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 9625 sqlite3 *db, 9626 const char *zSchema, 9627 sqlite3_snapshot **ppSnapshot 9628); 9629 9630/* 9631** CAPI3REF: Start a read transaction on an historical snapshot 9632** METHOD: sqlite3_snapshot 9633** 9634** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read 9635** transaction or upgrades an existing one for schema S of 9636** [database connection] D such that the read transaction refers to 9637** historical [snapshot] P, rather than the most recent change to the 9638** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK 9639** on success or an appropriate [error code] if it fails. 9640** 9641** ^In order to succeed, the database connection must not be in 9642** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there 9643** is already a read transaction open on schema S, then the database handle 9644** must have no active statements (SELECT statements that have been passed 9645** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()). 9646** SQLITE_ERROR is returned if either of these conditions is violated, or 9647** if schema S does not exist, or if the snapshot object is invalid. 9648** 9649** ^A call to sqlite3_snapshot_open() will fail to open if the specified 9650** snapshot has been overwritten by a [checkpoint]. In this case 9651** SQLITE_ERROR_SNAPSHOT is returned. 9652** 9653** If there is already a read transaction open when this function is 9654** invoked, then the same read transaction remains open (on the same 9655** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT 9656** is returned. If another error code - for example SQLITE_PROTOCOL or an 9657** SQLITE_IOERR error code - is returned, then the final state of the 9658** read transaction is undefined. If SQLITE_OK is returned, then the 9659** read transaction is now open on database snapshot P. 9660** 9661** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 9662** database connection D does not know that the database file for 9663** schema S is in [WAL mode]. A database connection might not know 9664** that the database file is in [WAL mode] if there has been no prior 9665** I/O on that database connection, or if the database entered [WAL mode] 9666** after the most recent I/O on the database connection.)^ 9667** (Hint: Run "[PRAGMA application_id]" against a newly opened 9668** database connection in order to make it ready to use snapshots.) 9669** 9670** The [sqlite3_snapshot_open()] interface is only available when the 9671** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9672*/ 9673SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 9674 sqlite3 *db, 9675 const char *zSchema, 9676 sqlite3_snapshot *pSnapshot 9677); 9678 9679/* 9680** CAPI3REF: Destroy a snapshot 9681** DESTRUCTOR: sqlite3_snapshot 9682** 9683** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 9684** The application must eventually free every [sqlite3_snapshot] object 9685** using this routine to avoid a memory leak. 9686** 9687** The [sqlite3_snapshot_free()] interface is only available when the 9688** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9689*/ 9690SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 9691 9692/* 9693** CAPI3REF: Compare the ages of two snapshot handles. 9694** METHOD: sqlite3_snapshot 9695** 9696** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 9697** of two valid snapshot handles. 9698** 9699** If the two snapshot handles are not associated with the same database 9700** file, the result of the comparison is undefined. 9701** 9702** Additionally, the result of the comparison is only valid if both of the 9703** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 9704** last time the wal file was deleted. The wal file is deleted when the 9705** database is changed back to rollback mode or when the number of database 9706** clients drops to zero. If either snapshot handle was obtained before the 9707** wal file was last deleted, the value returned by this function 9708** is undefined. 9709** 9710** Otherwise, this API returns a negative value if P1 refers to an older 9711** snapshot than P2, zero if the two handles refer to the same database 9712** snapshot, and a positive value if P1 is a newer snapshot than P2. 9713** 9714** This interface is only available if SQLite is compiled with the 9715** [SQLITE_ENABLE_SNAPSHOT] option. 9716*/ 9717SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 9718 sqlite3_snapshot *p1, 9719 sqlite3_snapshot *p2 9720); 9721 9722/* 9723** CAPI3REF: Recover snapshots from a wal file 9724** METHOD: sqlite3_snapshot 9725** 9726** If a [WAL file] remains on disk after all database connections close 9727** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control] 9728** or because the last process to have the database opened exited without 9729** calling [sqlite3_close()]) and a new connection is subsequently opened 9730** on that database and [WAL file], the [sqlite3_snapshot_open()] interface 9731** will only be able to open the last transaction added to the WAL file 9732** even though the WAL file contains other valid transactions. 9733** 9734** This function attempts to scan the WAL file associated with database zDb 9735** of database handle db and make all valid snapshots available to 9736** sqlite3_snapshot_open(). It is an error if there is already a read 9737** transaction open on the database, or if the database is not a WAL mode 9738** database. 9739** 9740** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 9741** 9742** This interface is only available if SQLite is compiled with the 9743** [SQLITE_ENABLE_SNAPSHOT] option. 9744*/ 9745SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 9746 9747/* 9748** CAPI3REF: Serialize a database 9749** 9750** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 9751** that is a serialization of the S database on [database connection] D. 9752** If P is not a NULL pointer, then the size of the database in bytes 9753** is written into *P. 9754** 9755** For an ordinary on-disk database file, the serialization is just a 9756** copy of the disk file. For an in-memory database or a "TEMP" database, 9757** the serialization is the same sequence of bytes which would be written 9758** to disk if that database where backed up to disk. 9759** 9760** The usual case is that sqlite3_serialize() copies the serialization of 9761** the database into memory obtained from [sqlite3_malloc64()] and returns 9762** a pointer to that memory. The caller is responsible for freeing the 9763** returned value to avoid a memory leak. However, if the F argument 9764** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 9765** are made, and the sqlite3_serialize() function will return a pointer 9766** to the contiguous memory representation of the database that SQLite 9767** is currently using for that database, or NULL if the no such contiguous 9768** memory representation of the database exists. A contiguous memory 9769** representation of the database will usually only exist if there has 9770** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 9771** values of D and S. 9772** The size of the database is written into *P even if the 9773** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy 9774** of the database exists. 9775** 9776** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 9777** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 9778** allocation error occurs. 9779** 9780** This interface is only available if SQLite is compiled with the 9781** [SQLITE_ENABLE_DESERIALIZE] option. 9782*/ 9783unsigned char *sqlite3_serialize( 9784 sqlite3 *db, /* The database connection */ 9785 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 9786 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 9787 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 9788); 9789 9790/* 9791** CAPI3REF: Flags for sqlite3_serialize 9792** 9793** Zero or more of the following constants can be OR-ed together for 9794** the F argument to [sqlite3_serialize(D,S,P,F)]. 9795** 9796** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 9797** a pointer to contiguous in-memory database that it is currently using, 9798** without making a copy of the database. If SQLite is not currently using 9799** a contiguous in-memory database, then this option causes 9800** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 9801** using a contiguous in-memory database if it has been initialized by a 9802** prior call to [sqlite3_deserialize()]. 9803*/ 9804#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 9805 9806/* 9807** CAPI3REF: Deserialize a database 9808** 9809** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 9810** [database connection] D to disconnect from database S and then 9811** reopen S as an in-memory database based on the serialization contained 9812** in P. The serialized database P is N bytes in size. M is the size of 9813** the buffer P, which might be larger than N. If M is larger than N, and 9814** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 9815** permitted to add content to the in-memory database as long as the total 9816** size does not exceed M bytes. 9817** 9818** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 9819** invoke sqlite3_free() on the serialization buffer when the database 9820** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 9821** SQLite will try to increase the buffer size using sqlite3_realloc64() 9822** if writes on the database cause it to grow larger than M bytes. 9823** 9824** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 9825** database is currently in a read transaction or is involved in a backup 9826** operation. 9827** 9828** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 9829** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 9830** [sqlite3_free()] is invoked on argument P prior to returning. 9831** 9832** This interface is only available if SQLite is compiled with the 9833** [SQLITE_ENABLE_DESERIALIZE] option. 9834*/ 9835int sqlite3_deserialize( 9836 sqlite3 *db, /* The database connection */ 9837 const char *zSchema, /* Which DB to reopen with the deserialization */ 9838 unsigned char *pData, /* The serialized database content */ 9839 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 9840 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 9841 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 9842); 9843 9844/* 9845** CAPI3REF: Flags for sqlite3_deserialize() 9846** 9847** The following are allowed values for 6th argument (the F argument) to 9848** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 9849** 9850** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 9851** in the P argument is held in memory obtained from [sqlite3_malloc64()] 9852** and that SQLite should take ownership of this memory and automatically 9853** free it when it has finished using it. Without this flag, the caller 9854** is responsible for freeing any dynamically allocated memory. 9855** 9856** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 9857** grow the size of the database using calls to [sqlite3_realloc64()]. This 9858** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 9859** Without this flag, the deserialized database cannot increase in size beyond 9860** the number of bytes specified by the M parameter. 9861** 9862** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 9863** should be treated as read-only. 9864*/ 9865#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 9866#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 9867#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 9868 9869/* 9870** Undo the hack that converts floating point types to integer for 9871** builds on processors without floating point support. 9872*/ 9873#ifdef SQLITE_OMIT_FLOATING_POINT 9874# undef double 9875#endif 9876 9877#ifdef __cplusplus 9878} /* End of the 'extern "C"' block */ 9879#endif 9880#endif /* SQLITE3_H */ 9881