1/* 2** 2001-09-15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are supposed to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef SQLITE3_H 34#define SQLITE3_H 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_APICALL 58# define SQLITE_APICALL 59#endif 60#ifndef SQLITE_STDCALL 61# define SQLITE_STDCALL SQLITE_APICALL 62#endif 63#ifndef SQLITE_CALLBACK 64# define SQLITE_CALLBACK 65#endif 66#ifndef SQLITE_SYSAPI 67# define SQLITE_SYSAPI 68#endif 69 70/* 71** These no-op macros are used in front of interfaces to mark those 72** interfaces as either deprecated or experimental. New applications 73** should not use deprecated interfaces - they are supported for backwards 74** compatibility only. Application writers should be aware that 75** experimental interfaces are subject to change in point releases. 76** 77** These macros used to resolve to various kinds of compiler magic that 78** would generate warning messages when they were used. But that 79** compiler magic ended up generating such a flurry of bug reports 80** that we have taken it all out and gone back to using simple 81** noop macros. 82*/ 83#define SQLITE_DEPRECATED 84#define SQLITE_EXPERIMENTAL 85 86/* 87** Ensure these symbols were not defined by some previous header file. 88*/ 89#ifdef SQLITE_VERSION 90# undef SQLITE_VERSION 91#endif 92#ifdef SQLITE_VERSION_NUMBER 93# undef SQLITE_VERSION_NUMBER 94#endif 95 96/* 97** CAPI3REF: Compile-Time Library Version Numbers 98** 99** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 100** evaluates to a string literal that is the SQLite version in the 101** format "X.Y.Z" where X is the major version number (always 3 for 102** SQLite3) and Y is the minor version number and Z is the release number.)^ 103** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 104** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 105** numbers used in [SQLITE_VERSION].)^ 106** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 107** be larger than the release from which it is derived. Either Y will 108** be held constant and Z will be incremented or else Y will be incremented 109** and Z will be reset to zero. 110** 111** Since [version 3.6.18] ([dateof:3.6.18]), 112** SQLite source code has been stored in the 113** <a href="http://www.fossil-scm.org/">Fossil configuration management 114** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 115** a string which identifies a particular check-in of SQLite 116** within its configuration management system. ^The SQLITE_SOURCE_ID 117** string contains the date and time of the check-in (UTC) and a SHA1 118** or SHA3-256 hash of the entire source tree. If the source code has 119** been edited in any way since it was last checked in, then the last 120** four hexadecimal digits of the hash may be modified. 121** 122** See also: [sqlite3_libversion()], 123** [sqlite3_libversion_number()], [sqlite3_sourceid()], 124** [sqlite_version()] and [sqlite_source_id()]. 125*/ 126#define SQLITE_VERSION "--VERS--" 127#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 128#define SQLITE_SOURCE_ID "--SOURCE-ID--" 129 130/* 131** CAPI3REF: Run-Time Library Version Numbers 132** KEYWORDS: sqlite3_version sqlite3_sourceid 133** 134** These interfaces provide the same information as the [SQLITE_VERSION], 135** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 136** but are associated with the library instead of the header file. ^(Cautious 137** programmers might include assert() statements in their application to 138** verify that values returned by these interfaces match the macros in 139** the header, and thus ensure that the application is 140** compiled with matching library and header files. 141** 142** <blockquote><pre> 143** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 144** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 ); 145** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 146** </pre></blockquote>)^ 147** 148** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 149** macro. ^The sqlite3_libversion() function returns a pointer to the 150** to the sqlite3_version[] string constant. The sqlite3_libversion() 151** function is provided for use in DLLs since DLL users usually do not have 152** direct access to string constants within the DLL. ^The 153** sqlite3_libversion_number() function returns an integer equal to 154** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns 155** a pointer to a string constant whose value is the same as the 156** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built 157** using an edited copy of [the amalgamation], then the last four characters 158** of the hash might be different from [SQLITE_SOURCE_ID].)^ 159** 160** See also: [sqlite_version()] and [sqlite_source_id()]. 161*/ 162SQLITE_EXTERN const char sqlite3_version[]; 163const char *sqlite3_libversion(void); 164const char *sqlite3_sourceid(void); 165int sqlite3_libversion_number(void); 166 167/* 168** CAPI3REF: Run-Time Library Compilation Options Diagnostics 169** 170** ^The sqlite3_compileoption_used() function returns 0 or 1 171** indicating whether the specified option was defined at 172** compile time. ^The SQLITE_ prefix may be omitted from the 173** option name passed to sqlite3_compileoption_used(). 174** 175** ^The sqlite3_compileoption_get() function allows iterating 176** over the list of options that were defined at compile time by 177** returning the N-th compile time option string. ^If N is out of range, 178** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 179** prefix is omitted from any strings returned by 180** sqlite3_compileoption_get(). 181** 182** ^Support for the diagnostic functions sqlite3_compileoption_used() 183** and sqlite3_compileoption_get() may be omitted by specifying the 184** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 185** 186** See also: SQL functions [sqlite_compileoption_used()] and 187** [sqlite_compileoption_get()] and the [compile_options pragma]. 188*/ 189#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 190int sqlite3_compileoption_used(const char *zOptName); 191const char *sqlite3_compileoption_get(int N); 192#else 193# define sqlite3_compileoption_used(X) 0 194# define sqlite3_compileoption_get(X) ((void*)0) 195#endif 196 197/* 198** CAPI3REF: Test To See If The Library Is Threadsafe 199** 200** ^The sqlite3_threadsafe() function returns zero if and only if 201** SQLite was compiled with mutexing code omitted due to the 202** [SQLITE_THREADSAFE] compile-time option being set to 0. 203** 204** SQLite can be compiled with or without mutexes. When 205** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 206** are enabled and SQLite is threadsafe. When the 207** [SQLITE_THREADSAFE] macro is 0, 208** the mutexes are omitted. Without the mutexes, it is not safe 209** to use SQLite concurrently from more than one thread. 210** 211** Enabling mutexes incurs a measurable performance penalty. 212** So if speed is of utmost importance, it makes sense to disable 213** the mutexes. But for maximum safety, mutexes should be enabled. 214** ^The default behavior is for mutexes to be enabled. 215** 216** This interface can be used by an application to make sure that the 217** version of SQLite that it is linking against was compiled with 218** the desired setting of the [SQLITE_THREADSAFE] macro. 219** 220** This interface only reports on the compile-time mutex setting 221** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 222** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 223** can be fully or partially disabled using a call to [sqlite3_config()] 224** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 225** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 226** sqlite3_threadsafe() function shows only the compile-time setting of 227** thread safety, not any run-time changes to that setting made by 228** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 229** is unchanged by calls to sqlite3_config().)^ 230** 231** See the [threading mode] documentation for additional information. 232*/ 233int sqlite3_threadsafe(void); 234 235/* 236** CAPI3REF: Database Connection Handle 237** KEYWORDS: {database connection} {database connections} 238** 239** Each open SQLite database is represented by a pointer to an instance of 240** the opaque structure named "sqlite3". It is useful to think of an sqlite3 241** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 242** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 243** and [sqlite3_close_v2()] are its destructors. There are many other 244** interfaces (such as 245** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 246** [sqlite3_busy_timeout()] to name but three) that are methods on an 247** sqlite3 object. 248*/ 249typedef struct sqlite3 sqlite3; 250 251/* 252** CAPI3REF: 64-Bit Integer Types 253** KEYWORDS: sqlite_int64 sqlite_uint64 254** 255** Because there is no cross-platform way to specify 64-bit integer types 256** SQLite includes typedefs for 64-bit signed and unsigned integers. 257** 258** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 259** The sqlite_int64 and sqlite_uint64 types are supported for backwards 260** compatibility only. 261** 262** ^The sqlite3_int64 and sqlite_int64 types can store integer values 263** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 264** sqlite3_uint64 and sqlite_uint64 types can store integer values 265** between 0 and +18446744073709551615 inclusive. 266*/ 267#ifdef SQLITE_INT64_TYPE 268 typedef SQLITE_INT64_TYPE sqlite_int64; 269# ifdef SQLITE_UINT64_TYPE 270 typedef SQLITE_UINT64_TYPE sqlite_uint64; 271# else 272 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 273# endif 274#elif defined(_MSC_VER) || defined(__BORLANDC__) 275 typedef __int64 sqlite_int64; 276 typedef unsigned __int64 sqlite_uint64; 277#else 278 typedef long long int sqlite_int64; 279 typedef unsigned long long int sqlite_uint64; 280#endif 281typedef sqlite_int64 sqlite3_int64; 282typedef sqlite_uint64 sqlite3_uint64; 283 284/* 285** If compiling for a processor that lacks floating point support, 286** substitute integer for floating-point. 287*/ 288#ifdef SQLITE_OMIT_FLOATING_POINT 289# define double sqlite3_int64 290#endif 291 292/* 293** CAPI3REF: Closing A Database Connection 294** DESTRUCTOR: sqlite3 295** 296** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 297** for the [sqlite3] object. 298** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 299** the [sqlite3] object is successfully destroyed and all associated 300** resources are deallocated. 301** 302** Ideally, applications should [sqlite3_finalize | finalize] all 303** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and 304** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 305** with the [sqlite3] object prior to attempting to close the object. 306** ^If the database connection is associated with unfinalized prepared 307** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then 308** sqlite3_close() will leave the database connection open and return 309** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared 310** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups, 311** it returns [SQLITE_OK] regardless, but instead of deallocating the database 312** connection immediately, it marks the database connection as an unusable 313** "zombie" and makes arrangements to automatically deallocate the database 314** connection after all prepared statements are finalized, all BLOB handles 315** are closed, and all backups have finished. The sqlite3_close_v2() interface 316** is intended for use with host languages that are garbage collected, and 317** where the order in which destructors are called is arbitrary. 318** 319** ^If an [sqlite3] object is destroyed while a transaction is open, 320** the transaction is automatically rolled back. 321** 322** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 323** must be either a NULL 324** pointer or an [sqlite3] object pointer obtained 325** from [sqlite3_open()], [sqlite3_open16()], or 326** [sqlite3_open_v2()], and not previously closed. 327** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 328** argument is a harmless no-op. 329*/ 330int sqlite3_close(sqlite3*); 331int sqlite3_close_v2(sqlite3*); 332 333/* 334** The type for a callback function. 335** This is legacy and deprecated. It is included for historical 336** compatibility and is not documented. 337*/ 338typedef int (*sqlite3_callback)(void*,int,char**, char**); 339 340/* 341** CAPI3REF: One-Step Query Execution Interface 342** METHOD: sqlite3 343** 344** The sqlite3_exec() interface is a convenience wrapper around 345** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 346** that allows an application to run multiple statements of SQL 347** without having to use a lot of C code. 348** 349** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 350** semicolon-separate SQL statements passed into its 2nd argument, 351** in the context of the [database connection] passed in as its 1st 352** argument. ^If the callback function of the 3rd argument to 353** sqlite3_exec() is not NULL, then it is invoked for each result row 354** coming out of the evaluated SQL statements. ^The 4th argument to 355** sqlite3_exec() is relayed through to the 1st argument of each 356** callback invocation. ^If the callback pointer to sqlite3_exec() 357** is NULL, then no callback is ever invoked and result rows are 358** ignored. 359** 360** ^If an error occurs while evaluating the SQL statements passed into 361** sqlite3_exec(), then execution of the current statement stops and 362** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 363** is not NULL then any error message is written into memory obtained 364** from [sqlite3_malloc()] and passed back through the 5th parameter. 365** To avoid memory leaks, the application should invoke [sqlite3_free()] 366** on error message strings returned through the 5th parameter of 367** sqlite3_exec() after the error message string is no longer needed. 368** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 369** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 370** NULL before returning. 371** 372** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 373** routine returns SQLITE_ABORT without invoking the callback again and 374** without running any subsequent SQL statements. 375** 376** ^The 2nd argument to the sqlite3_exec() callback function is the 377** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 378** callback is an array of pointers to strings obtained as if from 379** [sqlite3_column_text()], one for each column. ^If an element of a 380** result row is NULL then the corresponding string pointer for the 381** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 382** sqlite3_exec() callback is an array of pointers to strings where each 383** entry represents the name of corresponding result column as obtained 384** from [sqlite3_column_name()]. 385** 386** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 387** to an empty string, or a pointer that contains only whitespace and/or 388** SQL comments, then no SQL statements are evaluated and the database 389** is not changed. 390** 391** Restrictions: 392** 393** <ul> 394** <li> The application must ensure that the 1st parameter to sqlite3_exec() 395** is a valid and open [database connection]. 396** <li> The application must not close the [database connection] specified by 397** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 398** <li> The application must not modify the SQL statement text passed into 399** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 400** </ul> 401*/ 402int sqlite3_exec( 403 sqlite3*, /* An open database */ 404 const char *sql, /* SQL to be evaluated */ 405 int (*callback)(void*,int,char**,char**), /* Callback function */ 406 void *, /* 1st argument to callback */ 407 char **errmsg /* Error msg written here */ 408); 409 410/* 411** CAPI3REF: Result Codes 412** KEYWORDS: {result code definitions} 413** 414** Many SQLite functions return an integer result code from the set shown 415** here in order to indicate success or failure. 416** 417** New error codes may be added in future versions of SQLite. 418** 419** See also: [extended result code definitions] 420*/ 421#define SQLITE_OK 0 /* Successful result */ 422/* beginning-of-error-codes */ 423#define SQLITE_ERROR 1 /* Generic error */ 424#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 425#define SQLITE_PERM 3 /* Access permission denied */ 426#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 427#define SQLITE_BUSY 5 /* The database file is locked */ 428#define SQLITE_LOCKED 6 /* A table in the database is locked */ 429#define SQLITE_NOMEM 7 /* A malloc() failed */ 430#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 431#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 432#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 433#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 434#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 435#define SQLITE_FULL 13 /* Insertion failed because database is full */ 436#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 437#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 438#define SQLITE_EMPTY 16 /* Internal use only */ 439#define SQLITE_SCHEMA 17 /* The database schema changed */ 440#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 441#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 442#define SQLITE_MISMATCH 20 /* Data type mismatch */ 443#define SQLITE_MISUSE 21 /* Library used incorrectly */ 444#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 445#define SQLITE_AUTH 23 /* Authorization denied */ 446#define SQLITE_FORMAT 24 /* Not used */ 447#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 448#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 449#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 450#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 451#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 452#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 453/* end-of-error-codes */ 454 455/* 456** CAPI3REF: Extended Result Codes 457** KEYWORDS: {extended result code definitions} 458** 459** In its default configuration, SQLite API routines return one of 30 integer 460** [result codes]. However, experience has shown that many of 461** these result codes are too coarse-grained. They do not provide as 462** much information about problems as programmers might like. In an effort to 463** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 464** and later) include 465** support for additional result codes that provide more detailed information 466** about errors. These [extended result codes] are enabled or disabled 467** on a per database connection basis using the 468** [sqlite3_extended_result_codes()] API. Or, the extended code for 469** the most recent error can be obtained using 470** [sqlite3_extended_errcode()]. 471*/ 472#define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8)) 473#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8)) 474#define SQLITE_ERROR_SNAPSHOT (SQLITE_ERROR | (3<<8)) 475#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 476#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 477#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 478#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 479#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 480#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 481#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 482#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 483#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 484#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 485#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 486#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 487#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 488#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 489#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 490#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 491#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 492#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 493#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 494#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 495#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 496#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 497#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 498#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 499#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 500#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 501#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 502#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 503#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 504#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 505#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 506#define SQLITE_IOERR_DATA (SQLITE_IOERR | (32<<8)) 507#define SQLITE_IOERR_CORRUPTFS (SQLITE_IOERR | (33<<8)) 508#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 509#define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8)) 510#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 511#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 512#define SQLITE_BUSY_TIMEOUT (SQLITE_BUSY | (3<<8)) 513#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 514#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 515#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 516#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 517#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */ 518#define SQLITE_CANTOPEN_SYMLINK (SQLITE_CANTOPEN | (6<<8)) 519#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 520#define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8)) 521#define SQLITE_CORRUPT_INDEX (SQLITE_CORRUPT | (3<<8)) 522#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 523#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 524#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 525#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 526#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8)) 527#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8)) 528#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 529#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 530#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 531#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 532#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 533#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 534#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 535#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 536#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 537#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 538#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 539#define SQLITE_CONSTRAINT_PINNED (SQLITE_CONSTRAINT |(11<<8)) 540#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 541#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 542#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 543#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 544#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 545#define SQLITE_OK_SYMLINK (SQLITE_OK | (2<<8)) 546 547/* 548** CAPI3REF: Flags For File Open Operations 549** 550** These bit values are intended for use in the 551** 3rd parameter to the [sqlite3_open_v2()] interface and 552** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 553*/ 554#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 555#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 556#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 557#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 558#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 559#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 560#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 561#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 562#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 563#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 564#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 565#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 566#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 567#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 568#define SQLITE_OPEN_SUPER_JOURNAL 0x00004000 /* VFS only */ 569#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 570#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 571#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 572#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 573#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 574#define SQLITE_OPEN_NOFOLLOW 0x01000000 /* Ok for sqlite3_open_v2() */ 575 576/* Reserved: 0x00F00000 */ 577/* Legacy compatibility: */ 578#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 579 580 581/* 582** CAPI3REF: Device Characteristics 583** 584** The xDeviceCharacteristics method of the [sqlite3_io_methods] 585** object returns an integer which is a vector of these 586** bit values expressing I/O characteristics of the mass storage 587** device that holds the file that the [sqlite3_io_methods] 588** refers to. 589** 590** The SQLITE_IOCAP_ATOMIC property means that all writes of 591** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 592** mean that writes of blocks that are nnn bytes in size and 593** are aligned to an address which is an integer multiple of 594** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 595** that when data is appended to a file, the data is appended 596** first then the size of the file is extended, never the other 597** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 598** information is written to disk in the same order as calls 599** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 600** after reboot following a crash or power loss, the only bytes in a 601** file that were written at the application level might have changed 602** and that adjacent bytes, even bytes within the same sector are 603** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 604** flag indicates that a file cannot be deleted when open. The 605** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 606** read-only media and cannot be changed even by processes with 607** elevated privileges. 608** 609** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 610** filesystem supports doing multiple write operations atomically when those 611** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 612** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 613*/ 614#define SQLITE_IOCAP_ATOMIC 0x00000001 615#define SQLITE_IOCAP_ATOMIC512 0x00000002 616#define SQLITE_IOCAP_ATOMIC1K 0x00000004 617#define SQLITE_IOCAP_ATOMIC2K 0x00000008 618#define SQLITE_IOCAP_ATOMIC4K 0x00000010 619#define SQLITE_IOCAP_ATOMIC8K 0x00000020 620#define SQLITE_IOCAP_ATOMIC16K 0x00000040 621#define SQLITE_IOCAP_ATOMIC32K 0x00000080 622#define SQLITE_IOCAP_ATOMIC64K 0x00000100 623#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 624#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 625#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 626#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 627#define SQLITE_IOCAP_IMMUTABLE 0x00002000 628#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 629 630/* 631** CAPI3REF: File Locking Levels 632** 633** SQLite uses one of these integer values as the second 634** argument to calls it makes to the xLock() and xUnlock() methods 635** of an [sqlite3_io_methods] object. 636*/ 637#define SQLITE_LOCK_NONE 0 638#define SQLITE_LOCK_SHARED 1 639#define SQLITE_LOCK_RESERVED 2 640#define SQLITE_LOCK_PENDING 3 641#define SQLITE_LOCK_EXCLUSIVE 4 642 643/* 644** CAPI3REF: Synchronization Type Flags 645** 646** When SQLite invokes the xSync() method of an 647** [sqlite3_io_methods] object it uses a combination of 648** these integer values as the second argument. 649** 650** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 651** sync operation only needs to flush data to mass storage. Inode 652** information need not be flushed. If the lower four bits of the flag 653** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 654** If the lower four bits equal SQLITE_SYNC_FULL, that means 655** to use Mac OS X style fullsync instead of fsync(). 656** 657** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 658** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 659** settings. The [synchronous pragma] determines when calls to the 660** xSync VFS method occur and applies uniformly across all platforms. 661** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 662** energetic or rigorous or forceful the sync operations are and 663** only make a difference on Mac OSX for the default SQLite code. 664** (Third-party VFS implementations might also make the distinction 665** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 666** operating systems natively supported by SQLite, only Mac OSX 667** cares about the difference.) 668*/ 669#define SQLITE_SYNC_NORMAL 0x00002 670#define SQLITE_SYNC_FULL 0x00003 671#define SQLITE_SYNC_DATAONLY 0x00010 672 673/* 674** CAPI3REF: OS Interface Open File Handle 675** 676** An [sqlite3_file] object represents an open file in the 677** [sqlite3_vfs | OS interface layer]. Individual OS interface 678** implementations will 679** want to subclass this object by appending additional fields 680** for their own use. The pMethods entry is a pointer to an 681** [sqlite3_io_methods] object that defines methods for performing 682** I/O operations on the open file. 683*/ 684typedef struct sqlite3_file sqlite3_file; 685struct sqlite3_file { 686 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 687}; 688 689/* 690** CAPI3REF: OS Interface File Virtual Methods Object 691** 692** Every file opened by the [sqlite3_vfs.xOpen] method populates an 693** [sqlite3_file] object (or, more commonly, a subclass of the 694** [sqlite3_file] object) with a pointer to an instance of this object. 695** This object defines the methods used to perform various operations 696** against the open file represented by the [sqlite3_file] object. 697** 698** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 699** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 700** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 701** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 702** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 703** to NULL. 704** 705** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 706** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 707** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 708** flag may be ORed in to indicate that only the data of the file 709** and not its inode needs to be synced. 710** 711** The integer values to xLock() and xUnlock() are one of 712** <ul> 713** <li> [SQLITE_LOCK_NONE], 714** <li> [SQLITE_LOCK_SHARED], 715** <li> [SQLITE_LOCK_RESERVED], 716** <li> [SQLITE_LOCK_PENDING], or 717** <li> [SQLITE_LOCK_EXCLUSIVE]. 718** </ul> 719** xLock() increases the lock. xUnlock() decreases the lock. 720** The xCheckReservedLock() method checks whether any database connection, 721** either in this process or in some other process, is holding a RESERVED, 722** PENDING, or EXCLUSIVE lock on the file. It returns true 723** if such a lock exists and false otherwise. 724** 725** The xFileControl() method is a generic interface that allows custom 726** VFS implementations to directly control an open file using the 727** [sqlite3_file_control()] interface. The second "op" argument is an 728** integer opcode. The third argument is a generic pointer intended to 729** point to a structure that may contain arguments or space in which to 730** write return values. Potential uses for xFileControl() might be 731** functions to enable blocking locks with timeouts, to change the 732** locking strategy (for example to use dot-file locks), to inquire 733** about the status of a lock, or to break stale locks. The SQLite 734** core reserves all opcodes less than 100 for its own use. 735** A [file control opcodes | list of opcodes] less than 100 is available. 736** Applications that define a custom xFileControl method should use opcodes 737** greater than 100 to avoid conflicts. VFS implementations should 738** return [SQLITE_NOTFOUND] for file control opcodes that they do not 739** recognize. 740** 741** The xSectorSize() method returns the sector size of the 742** device that underlies the file. The sector size is the 743** minimum write that can be performed without disturbing 744** other bytes in the file. The xDeviceCharacteristics() 745** method returns a bit vector describing behaviors of the 746** underlying device: 747** 748** <ul> 749** <li> [SQLITE_IOCAP_ATOMIC] 750** <li> [SQLITE_IOCAP_ATOMIC512] 751** <li> [SQLITE_IOCAP_ATOMIC1K] 752** <li> [SQLITE_IOCAP_ATOMIC2K] 753** <li> [SQLITE_IOCAP_ATOMIC4K] 754** <li> [SQLITE_IOCAP_ATOMIC8K] 755** <li> [SQLITE_IOCAP_ATOMIC16K] 756** <li> [SQLITE_IOCAP_ATOMIC32K] 757** <li> [SQLITE_IOCAP_ATOMIC64K] 758** <li> [SQLITE_IOCAP_SAFE_APPEND] 759** <li> [SQLITE_IOCAP_SEQUENTIAL] 760** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 761** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 762** <li> [SQLITE_IOCAP_IMMUTABLE] 763** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 764** </ul> 765** 766** The SQLITE_IOCAP_ATOMIC property means that all writes of 767** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 768** mean that writes of blocks that are nnn bytes in size and 769** are aligned to an address which is an integer multiple of 770** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 771** that when data is appended to a file, the data is appended 772** first then the size of the file is extended, never the other 773** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 774** information is written to disk in the same order as calls 775** to xWrite(). 776** 777** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 778** in the unread portions of the buffer with zeros. A VFS that 779** fails to zero-fill short reads might seem to work. However, 780** failure to zero-fill short reads will eventually lead to 781** database corruption. 782*/ 783typedef struct sqlite3_io_methods sqlite3_io_methods; 784struct sqlite3_io_methods { 785 int iVersion; 786 int (*xClose)(sqlite3_file*); 787 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 788 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 789 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 790 int (*xSync)(sqlite3_file*, int flags); 791 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 792 int (*xLock)(sqlite3_file*, int); 793 int (*xUnlock)(sqlite3_file*, int); 794 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 795 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 796 int (*xSectorSize)(sqlite3_file*); 797 int (*xDeviceCharacteristics)(sqlite3_file*); 798 /* Methods above are valid for version 1 */ 799 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 800 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 801 void (*xShmBarrier)(sqlite3_file*); 802 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 803 /* Methods above are valid for version 2 */ 804 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 805 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 806 /* Methods above are valid for version 3 */ 807 /* Additional methods may be added in future releases */ 808}; 809 810/* 811** CAPI3REF: Standard File Control Opcodes 812** KEYWORDS: {file control opcodes} {file control opcode} 813** 814** These integer constants are opcodes for the xFileControl method 815** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 816** interface. 817** 818** <ul> 819** <li>[[SQLITE_FCNTL_LOCKSTATE]] 820** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 821** opcode causes the xFileControl method to write the current state of 822** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 823** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 824** into an integer that the pArg argument points to. This capability 825** is used during testing and is only available when the SQLITE_TEST 826** compile-time option is used. 827** 828** <li>[[SQLITE_FCNTL_SIZE_HINT]] 829** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 830** layer a hint of how large the database file will grow to be during the 831** current transaction. This hint is not guaranteed to be accurate but it 832** is often close. The underlying VFS might choose to preallocate database 833** file space based on this hint in order to help writes to the database 834** file run faster. 835** 836** <li>[[SQLITE_FCNTL_SIZE_LIMIT]] 837** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that 838** implements [sqlite3_deserialize()] to set an upper bound on the size 839** of the in-memory database. The argument is a pointer to a [sqlite3_int64]. 840** If the integer pointed to is negative, then it is filled in with the 841** current limit. Otherwise the limit is set to the larger of the value 842** of the integer pointed to and the current database size. The integer 843** pointed to is set to the new limit. 844** 845** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 846** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 847** extends and truncates the database file in chunks of a size specified 848** by the user. The fourth argument to [sqlite3_file_control()] should 849** point to an integer (type int) containing the new chunk-size to use 850** for the nominated database. Allocating database file space in large 851** chunks (say 1MB at a time), may reduce file-system fragmentation and 852** improve performance on some systems. 853** 854** <li>[[SQLITE_FCNTL_FILE_POINTER]] 855** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 856** to the [sqlite3_file] object associated with a particular database 857** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 858** 859** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 860** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 861** to the [sqlite3_file] object associated with the journal file (either 862** the [rollback journal] or the [write-ahead log]) for a particular database 863** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 864** 865** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 866** No longer in use. 867** 868** <li>[[SQLITE_FCNTL_SYNC]] 869** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 870** sent to the VFS immediately before the xSync method is invoked on a 871** database file descriptor. Or, if the xSync method is not invoked 872** because the user has configured SQLite with 873** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 874** of the xSync method. In most cases, the pointer argument passed with 875** this file-control is NULL. However, if the database file is being synced 876** as part of a multi-database commit, the argument points to a nul-terminated 877** string containing the transactions super-journal file name. VFSes that 878** do not need this signal should silently ignore this opcode. Applications 879** should not call [sqlite3_file_control()] with this opcode as doing so may 880** disrupt the operation of the specialized VFSes that do require it. 881** 882** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 883** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 884** and sent to the VFS after a transaction has been committed immediately 885** but before the database is unlocked. VFSes that do not need this signal 886** should silently ignore this opcode. Applications should not call 887** [sqlite3_file_control()] with this opcode as doing so may disrupt the 888** operation of the specialized VFSes that do require it. 889** 890** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 891** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 892** retry counts and intervals for certain disk I/O operations for the 893** windows [VFS] in order to provide robustness in the presence of 894** anti-virus programs. By default, the windows VFS will retry file read, 895** file write, and file delete operations up to 10 times, with a delay 896** of 25 milliseconds before the first retry and with the delay increasing 897** by an additional 25 milliseconds with each subsequent retry. This 898** opcode allows these two values (10 retries and 25 milliseconds of delay) 899** to be adjusted. The values are changed for all database connections 900** within the same process. The argument is a pointer to an array of two 901** integers where the first integer is the new retry count and the second 902** integer is the delay. If either integer is negative, then the setting 903** is not changed but instead the prior value of that setting is written 904** into the array entry, allowing the current retry settings to be 905** interrogated. The zDbName parameter is ignored. 906** 907** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 908** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 909** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 910** write ahead log ([WAL file]) and shared memory 911** files used for transaction control 912** are automatically deleted when the latest connection to the database 913** closes. Setting persistent WAL mode causes those files to persist after 914** close. Persisting the files is useful when other processes that do not 915** have write permission on the directory containing the database file want 916** to read the database file, as the WAL and shared memory files must exist 917** in order for the database to be readable. The fourth parameter to 918** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 919** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 920** WAL mode. If the integer is -1, then it is overwritten with the current 921** WAL persistence setting. 922** 923** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 924** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 925** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 926** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 927** xDeviceCharacteristics methods. The fourth parameter to 928** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 929** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 930** mode. If the integer is -1, then it is overwritten with the current 931** zero-damage mode setting. 932** 933** <li>[[SQLITE_FCNTL_OVERWRITE]] 934** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 935** a write transaction to indicate that, unless it is rolled back for some 936** reason, the entire database file will be overwritten by the current 937** transaction. This is used by VACUUM operations. 938** 939** <li>[[SQLITE_FCNTL_VFSNAME]] 940** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 941** all [VFSes] in the VFS stack. The names are of all VFS shims and the 942** final bottom-level VFS are written into memory obtained from 943** [sqlite3_malloc()] and the result is stored in the char* variable 944** that the fourth parameter of [sqlite3_file_control()] points to. 945** The caller is responsible for freeing the memory when done. As with 946** all file-control actions, there is no guarantee that this will actually 947** do anything. Callers should initialize the char* variable to a NULL 948** pointer in case this file-control is not implemented. This file-control 949** is intended for diagnostic use only. 950** 951** <li>[[SQLITE_FCNTL_VFS_POINTER]] 952** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 953** [VFSes] currently in use. ^(The argument X in 954** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 955** of type "[sqlite3_vfs] **". This opcodes will set *X 956** to a pointer to the top-level VFS.)^ 957** ^When there are multiple VFS shims in the stack, this opcode finds the 958** upper-most shim only. 959** 960** <li>[[SQLITE_FCNTL_PRAGMA]] 961** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 962** file control is sent to the open [sqlite3_file] object corresponding 963** to the database file to which the pragma statement refers. ^The argument 964** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 965** pointers to strings (char**) in which the second element of the array 966** is the name of the pragma and the third element is the argument to the 967** pragma or NULL if the pragma has no argument. ^The handler for an 968** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 969** of the char** argument point to a string obtained from [sqlite3_mprintf()] 970** or the equivalent and that string will become the result of the pragma or 971** the error message if the pragma fails. ^If the 972** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 973** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 974** file control returns [SQLITE_OK], then the parser assumes that the 975** VFS has handled the PRAGMA itself and the parser generates a no-op 976** prepared statement if result string is NULL, or that returns a copy 977** of the result string if the string is non-NULL. 978** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 979** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 980** that the VFS encountered an error while handling the [PRAGMA] and the 981** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 982** file control occurs at the beginning of pragma statement analysis and so 983** it is able to override built-in [PRAGMA] statements. 984** 985** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 986** ^The [SQLITE_FCNTL_BUSYHANDLER] 987** file-control may be invoked by SQLite on the database file handle 988** shortly after it is opened in order to provide a custom VFS with access 989** to the connection's busy-handler callback. The argument is of type (void**) 990** - an array of two (void *) values. The first (void *) actually points 991** to a function of type (int (*)(void *)). In order to invoke the connection's 992** busy-handler, this function should be invoked with the second (void *) in 993** the array as the only argument. If it returns non-zero, then the operation 994** should be retried. If it returns zero, the custom VFS should abandon the 995** current operation. 996** 997** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 998** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 999** to have SQLite generate a 1000** temporary filename using the same algorithm that is followed to generate 1001** temporary filenames for TEMP tables and other internal uses. The 1002** argument should be a char** which will be filled with the filename 1003** written into memory obtained from [sqlite3_malloc()]. The caller should 1004** invoke [sqlite3_free()] on the result to avoid a memory leak. 1005** 1006** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 1007** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 1008** maximum number of bytes that will be used for memory-mapped I/O. 1009** The argument is a pointer to a value of type sqlite3_int64 that 1010** is an advisory maximum number of bytes in the file to memory map. The 1011** pointer is overwritten with the old value. The limit is not changed if 1012** the value originally pointed to is negative, and so the current limit 1013** can be queried by passing in a pointer to a negative number. This 1014** file-control is used internally to implement [PRAGMA mmap_size]. 1015** 1016** <li>[[SQLITE_FCNTL_TRACE]] 1017** The [SQLITE_FCNTL_TRACE] file control provides advisory information 1018** to the VFS about what the higher layers of the SQLite stack are doing. 1019** This file control is used by some VFS activity tracing [shims]. 1020** The argument is a zero-terminated string. Higher layers in the 1021** SQLite stack may generate instances of this file control if 1022** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 1023** 1024** <li>[[SQLITE_FCNTL_HAS_MOVED]] 1025** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 1026** pointer to an integer and it writes a boolean into that integer depending 1027** on whether or not the file has been renamed, moved, or deleted since it 1028** was first opened. 1029** 1030** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1031** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1032** underlying native file handle associated with a file handle. This file 1033** control interprets its argument as a pointer to a native file handle and 1034** writes the resulting value there. 1035** 1036** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1037** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1038** opcode causes the xFileControl method to swap the file handle with the one 1039** pointed to by the pArg argument. This capability is used during testing 1040** and only needs to be supported when SQLITE_TEST is defined. 1041** 1042** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1043** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1044** be advantageous to block on the next WAL lock if the lock is not immediately 1045** available. The WAL subsystem issues this signal during rare 1046** circumstances in order to fix a problem with priority inversion. 1047** Applications should <em>not</em> use this file-control. 1048** 1049** <li>[[SQLITE_FCNTL_ZIPVFS]] 1050** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1051** VFS should return SQLITE_NOTFOUND for this opcode. 1052** 1053** <li>[[SQLITE_FCNTL_RBU]] 1054** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1055** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1056** this opcode. 1057** 1058** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1059** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1060** the file descriptor is placed in "batch write mode", which 1061** means all subsequent write operations will be deferred and done 1062** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1063** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1064** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1065** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1066** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1067** no VFS interface calls on the same [sqlite3_file] file descriptor 1068** except for calls to the xWrite method and the xFileControl method 1069** with [SQLITE_FCNTL_SIZE_HINT]. 1070** 1071** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1072** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1073** operations since the previous successful call to 1074** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1075** This file control returns [SQLITE_OK] if and only if the writes were 1076** all performed successfully and have been committed to persistent storage. 1077** ^Regardless of whether or not it is successful, this file control takes 1078** the file descriptor out of batch write mode so that all subsequent 1079** write operations are independent. 1080** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1081** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1082** 1083** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1084** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1085** operations since the previous successful call to 1086** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1087** ^This file control takes the file descriptor out of batch write mode 1088** so that all subsequent write operations are independent. 1089** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1090** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1091** 1092** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]] 1093** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS 1094** to block for up to M milliseconds before failing when attempting to 1095** obtain a file lock using the xLock or xShmLock methods of the VFS. 1096** The parameter is a pointer to a 32-bit signed integer that contains 1097** the value that M is to be set to. Before returning, the 32-bit signed 1098** integer is overwritten with the previous value of M. 1099** 1100** <li>[[SQLITE_FCNTL_DATA_VERSION]] 1101** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to 1102** a database file. The argument is a pointer to a 32-bit unsigned integer. 1103** The "data version" for the pager is written into the pointer. The 1104** "data version" changes whenever any change occurs to the corresponding 1105** database file, either through SQL statements on the same database 1106** connection or through transactions committed by separate database 1107** connections possibly in other processes. The [sqlite3_total_changes()] 1108** interface can be used to find if any database on the connection has changed, 1109** but that interface responds to changes on TEMP as well as MAIN and does 1110** not provide a mechanism to detect changes to MAIN only. Also, the 1111** [sqlite3_total_changes()] interface responds to internal changes only and 1112** omits changes made by other database connections. The 1113** [PRAGMA data_version] command provides a mechanism to detect changes to 1114** a single attached database that occur due to other database connections, 1115** but omits changes implemented by the database connection on which it is 1116** called. This file control is the only mechanism to detect changes that 1117** happen either internally or externally and that are associated with 1118** a particular attached database. 1119** 1120** <li>[[SQLITE_FCNTL_CKPT_START]] 1121** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint 1122** in wal mode before the client starts to copy pages from the wal 1123** file to the database file. 1124** 1125** <li>[[SQLITE_FCNTL_CKPT_DONE]] 1126** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint 1127** in wal mode after the client has finished copying pages from the wal 1128** file to the database file, but before the *-shm file is updated to 1129** record the fact that the pages have been checkpointed. 1130** </ul> 1131** 1132** <li>[[SQLITE_FCNTL_EXTERNAL_READER]] 1133** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect 1134** whether or not there is a database client in another process with a wal-mode 1135** transaction open on the database or not. It is only available on unix.The 1136** (void*) argument passed with this file-control should be a pointer to a 1137** value of type (int). The integer value is set to 1 if the database is a wal 1138** mode database and there exists at least one client in another process that 1139** currently has an SQL transaction open on the database. It is set to 0 if 1140** the database is not a wal-mode db, or if there is no such connection in any 1141** other process. This opcode cannot be used to detect transactions opened 1142** by clients within the current process, only within other processes. 1143** </ul> 1144*/ 1145#define SQLITE_FCNTL_LOCKSTATE 1 1146#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1147#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1148#define SQLITE_FCNTL_LAST_ERRNO 4 1149#define SQLITE_FCNTL_SIZE_HINT 5 1150#define SQLITE_FCNTL_CHUNK_SIZE 6 1151#define SQLITE_FCNTL_FILE_POINTER 7 1152#define SQLITE_FCNTL_SYNC_OMITTED 8 1153#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1154#define SQLITE_FCNTL_PERSIST_WAL 10 1155#define SQLITE_FCNTL_OVERWRITE 11 1156#define SQLITE_FCNTL_VFSNAME 12 1157#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1158#define SQLITE_FCNTL_PRAGMA 14 1159#define SQLITE_FCNTL_BUSYHANDLER 15 1160#define SQLITE_FCNTL_TEMPFILENAME 16 1161#define SQLITE_FCNTL_MMAP_SIZE 18 1162#define SQLITE_FCNTL_TRACE 19 1163#define SQLITE_FCNTL_HAS_MOVED 20 1164#define SQLITE_FCNTL_SYNC 21 1165#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1166#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1167#define SQLITE_FCNTL_WAL_BLOCK 24 1168#define SQLITE_FCNTL_ZIPVFS 25 1169#define SQLITE_FCNTL_RBU 26 1170#define SQLITE_FCNTL_VFS_POINTER 27 1171#define SQLITE_FCNTL_JOURNAL_POINTER 28 1172#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1173#define SQLITE_FCNTL_PDB 30 1174#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1175#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1176#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1177#define SQLITE_FCNTL_LOCK_TIMEOUT 34 1178#define SQLITE_FCNTL_DATA_VERSION 35 1179#define SQLITE_FCNTL_SIZE_LIMIT 36 1180#define SQLITE_FCNTL_CKPT_DONE 37 1181#define SQLITE_FCNTL_RESERVE_BYTES 38 1182#define SQLITE_FCNTL_CKPT_START 39 1183 1184#define SQLITE_FCNTL_EXTERNAL_READER 40 1185 1186/* deprecated names */ 1187#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1188#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1189#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1190 1191 1192/* 1193** CAPI3REF: Mutex Handle 1194** 1195** The mutex module within SQLite defines [sqlite3_mutex] to be an 1196** abstract type for a mutex object. The SQLite core never looks 1197** at the internal representation of an [sqlite3_mutex]. It only 1198** deals with pointers to the [sqlite3_mutex] object. 1199** 1200** Mutexes are created using [sqlite3_mutex_alloc()]. 1201*/ 1202typedef struct sqlite3_mutex sqlite3_mutex; 1203 1204/* 1205** CAPI3REF: Loadable Extension Thunk 1206** 1207** A pointer to the opaque sqlite3_api_routines structure is passed as 1208** the third parameter to entry points of [loadable extensions]. This 1209** structure must be typedefed in order to work around compiler warnings 1210** on some platforms. 1211*/ 1212typedef struct sqlite3_api_routines sqlite3_api_routines; 1213 1214/* 1215** CAPI3REF: OS Interface Object 1216** 1217** An instance of the sqlite3_vfs object defines the interface between 1218** the SQLite core and the underlying operating system. The "vfs" 1219** in the name of the object stands for "virtual file system". See 1220** the [VFS | VFS documentation] for further information. 1221** 1222** The VFS interface is sometimes extended by adding new methods onto 1223** the end. Each time such an extension occurs, the iVersion field 1224** is incremented. The iVersion value started out as 1 in 1225** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1226** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1227** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1228** may be appended to the sqlite3_vfs object and the iVersion value 1229** may increase again in future versions of SQLite. 1230** Note that due to an oversight, the structure 1231** of the sqlite3_vfs object changed in the transition from 1232** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1233** and yet the iVersion field was not increased. 1234** 1235** The szOsFile field is the size of the subclassed [sqlite3_file] 1236** structure used by this VFS. mxPathname is the maximum length of 1237** a pathname in this VFS. 1238** 1239** Registered sqlite3_vfs objects are kept on a linked list formed by 1240** the pNext pointer. The [sqlite3_vfs_register()] 1241** and [sqlite3_vfs_unregister()] interfaces manage this list 1242** in a thread-safe way. The [sqlite3_vfs_find()] interface 1243** searches the list. Neither the application code nor the VFS 1244** implementation should use the pNext pointer. 1245** 1246** The pNext field is the only field in the sqlite3_vfs 1247** structure that SQLite will ever modify. SQLite will only access 1248** or modify this field while holding a particular static mutex. 1249** The application should never modify anything within the sqlite3_vfs 1250** object once the object has been registered. 1251** 1252** The zName field holds the name of the VFS module. The name must 1253** be unique across all VFS modules. 1254** 1255** [[sqlite3_vfs.xOpen]] 1256** ^SQLite guarantees that the zFilename parameter to xOpen 1257** is either a NULL pointer or string obtained 1258** from xFullPathname() with an optional suffix added. 1259** ^If a suffix is added to the zFilename parameter, it will 1260** consist of a single "-" character followed by no more than 1261** 11 alphanumeric and/or "-" characters. 1262** ^SQLite further guarantees that 1263** the string will be valid and unchanged until xClose() is 1264** called. Because of the previous sentence, 1265** the [sqlite3_file] can safely store a pointer to the 1266** filename if it needs to remember the filename for some reason. 1267** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1268** must invent its own temporary name for the file. ^Whenever the 1269** xFilename parameter is NULL it will also be the case that the 1270** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1271** 1272** The flags argument to xOpen() includes all bits set in 1273** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1274** or [sqlite3_open16()] is used, then flags includes at least 1275** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1276** If xOpen() opens a file read-only then it sets *pOutFlags to 1277** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1278** 1279** ^(SQLite will also add one of the following flags to the xOpen() 1280** call, depending on the object being opened: 1281** 1282** <ul> 1283** <li> [SQLITE_OPEN_MAIN_DB] 1284** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1285** <li> [SQLITE_OPEN_TEMP_DB] 1286** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1287** <li> [SQLITE_OPEN_TRANSIENT_DB] 1288** <li> [SQLITE_OPEN_SUBJOURNAL] 1289** <li> [SQLITE_OPEN_SUPER_JOURNAL] 1290** <li> [SQLITE_OPEN_WAL] 1291** </ul>)^ 1292** 1293** The file I/O implementation can use the object type flags to 1294** change the way it deals with files. For example, an application 1295** that does not care about crash recovery or rollback might make 1296** the open of a journal file a no-op. Writes to this journal would 1297** also be no-ops, and any attempt to read the journal would return 1298** SQLITE_IOERR. Or the implementation might recognize that a database 1299** file will be doing page-aligned sector reads and writes in a random 1300** order and set up its I/O subsystem accordingly. 1301** 1302** SQLite might also add one of the following flags to the xOpen method: 1303** 1304** <ul> 1305** <li> [SQLITE_OPEN_DELETEONCLOSE] 1306** <li> [SQLITE_OPEN_EXCLUSIVE] 1307** </ul> 1308** 1309** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1310** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1311** will be set for TEMP databases and their journals, transient 1312** databases, and subjournals. 1313** 1314** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1315** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1316** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1317** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1318** SQLITE_OPEN_CREATE, is used to indicate that file should always 1319** be created, and that it is an error if it already exists. 1320** It is <i>not</i> used to indicate the file should be opened 1321** for exclusive access. 1322** 1323** ^At least szOsFile bytes of memory are allocated by SQLite 1324** to hold the [sqlite3_file] structure passed as the third 1325** argument to xOpen. The xOpen method does not have to 1326** allocate the structure; it should just fill it in. Note that 1327** the xOpen method must set the sqlite3_file.pMethods to either 1328** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1329** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1330** element will be valid after xOpen returns regardless of the success 1331** or failure of the xOpen call. 1332** 1333** [[sqlite3_vfs.xAccess]] 1334** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1335** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1336** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1337** to test whether a file is at least readable. The SQLITE_ACCESS_READ 1338** flag is never actually used and is not implemented in the built-in 1339** VFSes of SQLite. The file is named by the second argument and can be a 1340** directory. The xAccess method returns [SQLITE_OK] on success or some 1341** non-zero error code if there is an I/O error or if the name of 1342** the file given in the second argument is illegal. If SQLITE_OK 1343** is returned, then non-zero or zero is written into *pResOut to indicate 1344** whether or not the file is accessible. 1345** 1346** ^SQLite will always allocate at least mxPathname+1 bytes for the 1347** output buffer xFullPathname. The exact size of the output buffer 1348** is also passed as a parameter to both methods. If the output buffer 1349** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1350** handled as a fatal error by SQLite, vfs implementations should endeavor 1351** to prevent this by setting mxPathname to a sufficiently large value. 1352** 1353** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1354** interfaces are not strictly a part of the filesystem, but they are 1355** included in the VFS structure for completeness. 1356** The xRandomness() function attempts to return nBytes bytes 1357** of good-quality randomness into zOut. The return value is 1358** the actual number of bytes of randomness obtained. 1359** The xSleep() method causes the calling thread to sleep for at 1360** least the number of microseconds given. ^The xCurrentTime() 1361** method returns a Julian Day Number for the current date and time as 1362** a floating point value. 1363** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1364** Day Number multiplied by 86400000 (the number of milliseconds in 1365** a 24-hour day). 1366** ^SQLite will use the xCurrentTimeInt64() method to get the current 1367** date and time if that method is available (if iVersion is 2 or 1368** greater and the function pointer is not NULL) and will fall back 1369** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1370** 1371** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1372** are not used by the SQLite core. These optional interfaces are provided 1373** by some VFSes to facilitate testing of the VFS code. By overriding 1374** system calls with functions under its control, a test program can 1375** simulate faults and error conditions that would otherwise be difficult 1376** or impossible to induce. The set of system calls that can be overridden 1377** varies from one VFS to another, and from one version of the same VFS to the 1378** next. Applications that use these interfaces must be prepared for any 1379** or all of these interfaces to be NULL or for their behavior to change 1380** from one release to the next. Applications must not attempt to access 1381** any of these methods if the iVersion of the VFS is less than 3. 1382*/ 1383typedef struct sqlite3_vfs sqlite3_vfs; 1384typedef void (*sqlite3_syscall_ptr)(void); 1385struct sqlite3_vfs { 1386 int iVersion; /* Structure version number (currently 3) */ 1387 int szOsFile; /* Size of subclassed sqlite3_file */ 1388 int mxPathname; /* Maximum file pathname length */ 1389 sqlite3_vfs *pNext; /* Next registered VFS */ 1390 const char *zName; /* Name of this virtual file system */ 1391 void *pAppData; /* Pointer to application-specific data */ 1392 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1393 int flags, int *pOutFlags); 1394 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1395 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1396 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1397 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1398 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1399 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1400 void (*xDlClose)(sqlite3_vfs*, void*); 1401 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1402 int (*xSleep)(sqlite3_vfs*, int microseconds); 1403 int (*xCurrentTime)(sqlite3_vfs*, double*); 1404 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1405 /* 1406 ** The methods above are in version 1 of the sqlite_vfs object 1407 ** definition. Those that follow are added in version 2 or later 1408 */ 1409 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1410 /* 1411 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1412 ** Those below are for version 3 and greater. 1413 */ 1414 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1415 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1416 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1417 /* 1418 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1419 ** New fields may be appended in future versions. The iVersion 1420 ** value will increment whenever this happens. 1421 */ 1422}; 1423 1424/* 1425** CAPI3REF: Flags for the xAccess VFS method 1426** 1427** These integer constants can be used as the third parameter to 1428** the xAccess method of an [sqlite3_vfs] object. They determine 1429** what kind of permissions the xAccess method is looking for. 1430** With SQLITE_ACCESS_EXISTS, the xAccess method 1431** simply checks whether the file exists. 1432** With SQLITE_ACCESS_READWRITE, the xAccess method 1433** checks whether the named directory is both readable and writable 1434** (in other words, if files can be added, removed, and renamed within 1435** the directory). 1436** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1437** [temp_store_directory pragma], though this could change in a future 1438** release of SQLite. 1439** With SQLITE_ACCESS_READ, the xAccess method 1440** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1441** currently unused, though it might be used in a future release of 1442** SQLite. 1443*/ 1444#define SQLITE_ACCESS_EXISTS 0 1445#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1446#define SQLITE_ACCESS_READ 2 /* Unused */ 1447 1448/* 1449** CAPI3REF: Flags for the xShmLock VFS method 1450** 1451** These integer constants define the various locking operations 1452** allowed by the xShmLock method of [sqlite3_io_methods]. The 1453** following are the only legal combinations of flags to the 1454** xShmLock method: 1455** 1456** <ul> 1457** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1458** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1459** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1460** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1461** </ul> 1462** 1463** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1464** was given on the corresponding lock. 1465** 1466** The xShmLock method can transition between unlocked and SHARED or 1467** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1468** and EXCLUSIVE. 1469*/ 1470#define SQLITE_SHM_UNLOCK 1 1471#define SQLITE_SHM_LOCK 2 1472#define SQLITE_SHM_SHARED 4 1473#define SQLITE_SHM_EXCLUSIVE 8 1474 1475/* 1476** CAPI3REF: Maximum xShmLock index 1477** 1478** The xShmLock method on [sqlite3_io_methods] may use values 1479** between 0 and this upper bound as its "offset" argument. 1480** The SQLite core will never attempt to acquire or release a 1481** lock outside of this range 1482*/ 1483#define SQLITE_SHM_NLOCK 8 1484 1485 1486/* 1487** CAPI3REF: Initialize The SQLite Library 1488** 1489** ^The sqlite3_initialize() routine initializes the 1490** SQLite library. ^The sqlite3_shutdown() routine 1491** deallocates any resources that were allocated by sqlite3_initialize(). 1492** These routines are designed to aid in process initialization and 1493** shutdown on embedded systems. Workstation applications using 1494** SQLite normally do not need to invoke either of these routines. 1495** 1496** A call to sqlite3_initialize() is an "effective" call if it is 1497** the first time sqlite3_initialize() is invoked during the lifetime of 1498** the process, or if it is the first time sqlite3_initialize() is invoked 1499** following a call to sqlite3_shutdown(). ^(Only an effective call 1500** of sqlite3_initialize() does any initialization. All other calls 1501** are harmless no-ops.)^ 1502** 1503** A call to sqlite3_shutdown() is an "effective" call if it is the first 1504** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1505** an effective call to sqlite3_shutdown() does any deinitialization. 1506** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1507** 1508** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1509** is not. The sqlite3_shutdown() interface must only be called from a 1510** single thread. All open [database connections] must be closed and all 1511** other SQLite resources must be deallocated prior to invoking 1512** sqlite3_shutdown(). 1513** 1514** Among other things, ^sqlite3_initialize() will invoke 1515** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1516** will invoke sqlite3_os_end(). 1517** 1518** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1519** ^If for some reason, sqlite3_initialize() is unable to initialize 1520** the library (perhaps it is unable to allocate a needed resource such 1521** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1522** 1523** ^The sqlite3_initialize() routine is called internally by many other 1524** SQLite interfaces so that an application usually does not need to 1525** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1526** calls sqlite3_initialize() so the SQLite library will be automatically 1527** initialized when [sqlite3_open()] is called if it has not be initialized 1528** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1529** compile-time option, then the automatic calls to sqlite3_initialize() 1530** are omitted and the application must call sqlite3_initialize() directly 1531** prior to using any other SQLite interface. For maximum portability, 1532** it is recommended that applications always invoke sqlite3_initialize() 1533** directly prior to using any other SQLite interface. Future releases 1534** of SQLite may require this. In other words, the behavior exhibited 1535** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1536** default behavior in some future release of SQLite. 1537** 1538** The sqlite3_os_init() routine does operating-system specific 1539** initialization of the SQLite library. The sqlite3_os_end() 1540** routine undoes the effect of sqlite3_os_init(). Typical tasks 1541** performed by these routines include allocation or deallocation 1542** of static resources, initialization of global variables, 1543** setting up a default [sqlite3_vfs] module, or setting up 1544** a default configuration using [sqlite3_config()]. 1545** 1546** The application should never invoke either sqlite3_os_init() 1547** or sqlite3_os_end() directly. The application should only invoke 1548** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1549** interface is called automatically by sqlite3_initialize() and 1550** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1551** implementations for sqlite3_os_init() and sqlite3_os_end() 1552** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1553** When [custom builds | built for other platforms] 1554** (using the [SQLITE_OS_OTHER=1] compile-time 1555** option) the application must supply a suitable implementation for 1556** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1557** implementation of sqlite3_os_init() or sqlite3_os_end() 1558** must return [SQLITE_OK] on success and some other [error code] upon 1559** failure. 1560*/ 1561int sqlite3_initialize(void); 1562int sqlite3_shutdown(void); 1563int sqlite3_os_init(void); 1564int sqlite3_os_end(void); 1565 1566/* 1567** CAPI3REF: Configuring The SQLite Library 1568** 1569** The sqlite3_config() interface is used to make global configuration 1570** changes to SQLite in order to tune SQLite to the specific needs of 1571** the application. The default configuration is recommended for most 1572** applications and so this routine is usually not necessary. It is 1573** provided to support rare applications with unusual needs. 1574** 1575** <b>The sqlite3_config() interface is not threadsafe. The application 1576** must ensure that no other SQLite interfaces are invoked by other 1577** threads while sqlite3_config() is running.</b> 1578** 1579** The sqlite3_config() interface 1580** may only be invoked prior to library initialization using 1581** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1582** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1583** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1584** Note, however, that ^sqlite3_config() can be called as part of the 1585** implementation of an application-defined [sqlite3_os_init()]. 1586** 1587** The first argument to sqlite3_config() is an integer 1588** [configuration option] that determines 1589** what property of SQLite is to be configured. Subsequent arguments 1590** vary depending on the [configuration option] 1591** in the first argument. 1592** 1593** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1594** ^If the option is unknown or SQLite is unable to set the option 1595** then this routine returns a non-zero [error code]. 1596*/ 1597int sqlite3_config(int, ...); 1598 1599/* 1600** CAPI3REF: Configure database connections 1601** METHOD: sqlite3 1602** 1603** The sqlite3_db_config() interface is used to make configuration 1604** changes to a [database connection]. The interface is similar to 1605** [sqlite3_config()] except that the changes apply to a single 1606** [database connection] (specified in the first argument). 1607** 1608** The second argument to sqlite3_db_config(D,V,...) is the 1609** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1610** that indicates what aspect of the [database connection] is being configured. 1611** Subsequent arguments vary depending on the configuration verb. 1612** 1613** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1614** the call is considered successful. 1615*/ 1616int sqlite3_db_config(sqlite3*, int op, ...); 1617 1618/* 1619** CAPI3REF: Memory Allocation Routines 1620** 1621** An instance of this object defines the interface between SQLite 1622** and low-level memory allocation routines. 1623** 1624** This object is used in only one place in the SQLite interface. 1625** A pointer to an instance of this object is the argument to 1626** [sqlite3_config()] when the configuration option is 1627** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1628** By creating an instance of this object 1629** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1630** during configuration, an application can specify an alternative 1631** memory allocation subsystem for SQLite to use for all of its 1632** dynamic memory needs. 1633** 1634** Note that SQLite comes with several [built-in memory allocators] 1635** that are perfectly adequate for the overwhelming majority of applications 1636** and that this object is only useful to a tiny minority of applications 1637** with specialized memory allocation requirements. This object is 1638** also used during testing of SQLite in order to specify an alternative 1639** memory allocator that simulates memory out-of-memory conditions in 1640** order to verify that SQLite recovers gracefully from such 1641** conditions. 1642** 1643** The xMalloc, xRealloc, and xFree methods must work like the 1644** malloc(), realloc() and free() functions from the standard C library. 1645** ^SQLite guarantees that the second argument to 1646** xRealloc is always a value returned by a prior call to xRoundup. 1647** 1648** xSize should return the allocated size of a memory allocation 1649** previously obtained from xMalloc or xRealloc. The allocated size 1650** is always at least as big as the requested size but may be larger. 1651** 1652** The xRoundup method returns what would be the allocated size of 1653** a memory allocation given a particular requested size. Most memory 1654** allocators round up memory allocations at least to the next multiple 1655** of 8. Some allocators round up to a larger multiple or to a power of 2. 1656** Every memory allocation request coming in through [sqlite3_malloc()] 1657** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1658** that causes the corresponding memory allocation to fail. 1659** 1660** The xInit method initializes the memory allocator. For example, 1661** it might allocate any required mutexes or initialize internal data 1662** structures. The xShutdown method is invoked (indirectly) by 1663** [sqlite3_shutdown()] and should deallocate any resources acquired 1664** by xInit. The pAppData pointer is used as the only parameter to 1665** xInit and xShutdown. 1666** 1667** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes 1668** the xInit method, so the xInit method need not be threadsafe. The 1669** xShutdown method is only called from [sqlite3_shutdown()] so it does 1670** not need to be threadsafe either. For all other methods, SQLite 1671** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1672** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1673** it is by default) and so the methods are automatically serialized. 1674** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1675** methods must be threadsafe or else make their own arrangements for 1676** serialization. 1677** 1678** SQLite will never invoke xInit() more than once without an intervening 1679** call to xShutdown(). 1680*/ 1681typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1682struct sqlite3_mem_methods { 1683 void *(*xMalloc)(int); /* Memory allocation function */ 1684 void (*xFree)(void*); /* Free a prior allocation */ 1685 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1686 int (*xSize)(void*); /* Return the size of an allocation */ 1687 int (*xRoundup)(int); /* Round up request size to allocation size */ 1688 int (*xInit)(void*); /* Initialize the memory allocator */ 1689 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1690 void *pAppData; /* Argument to xInit() and xShutdown() */ 1691}; 1692 1693/* 1694** CAPI3REF: Configuration Options 1695** KEYWORDS: {configuration option} 1696** 1697** These constants are the available integer configuration options that 1698** can be passed as the first argument to the [sqlite3_config()] interface. 1699** 1700** New configuration options may be added in future releases of SQLite. 1701** Existing configuration options might be discontinued. Applications 1702** should check the return code from [sqlite3_config()] to make sure that 1703** the call worked. The [sqlite3_config()] interface will return a 1704** non-zero [error code] if a discontinued or unsupported configuration option 1705** is invoked. 1706** 1707** <dl> 1708** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1709** <dd>There are no arguments to this option. ^This option sets the 1710** [threading mode] to Single-thread. In other words, it disables 1711** all mutexing and puts SQLite into a mode where it can only be used 1712** by a single thread. ^If SQLite is compiled with 1713** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1714** it is not possible to change the [threading mode] from its default 1715** value of Single-thread and so [sqlite3_config()] will return 1716** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1717** configuration option.</dd> 1718** 1719** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1720** <dd>There are no arguments to this option. ^This option sets the 1721** [threading mode] to Multi-thread. In other words, it disables 1722** mutexing on [database connection] and [prepared statement] objects. 1723** The application is responsible for serializing access to 1724** [database connections] and [prepared statements]. But other mutexes 1725** are enabled so that SQLite will be safe to use in a multi-threaded 1726** environment as long as no two threads attempt to use the same 1727** [database connection] at the same time. ^If SQLite is compiled with 1728** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1729** it is not possible to set the Multi-thread [threading mode] and 1730** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1731** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1732** 1733** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1734** <dd>There are no arguments to this option. ^This option sets the 1735** [threading mode] to Serialized. In other words, this option enables 1736** all mutexes including the recursive 1737** mutexes on [database connection] and [prepared statement] objects. 1738** In this mode (which is the default when SQLite is compiled with 1739** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1740** to [database connections] and [prepared statements] so that the 1741** application is free to use the same [database connection] or the 1742** same [prepared statement] in different threads at the same time. 1743** ^If SQLite is compiled with 1744** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1745** it is not possible to set the Serialized [threading mode] and 1746** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1747** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1748** 1749** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1750** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1751** a pointer to an instance of the [sqlite3_mem_methods] structure. 1752** The argument specifies 1753** alternative low-level memory allocation routines to be used in place of 1754** the memory allocation routines built into SQLite.)^ ^SQLite makes 1755** its own private copy of the content of the [sqlite3_mem_methods] structure 1756** before the [sqlite3_config()] call returns.</dd> 1757** 1758** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1759** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1760** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1761** The [sqlite3_mem_methods] 1762** structure is filled with the currently defined memory allocation routines.)^ 1763** This option can be used to overload the default memory allocation 1764** routines with a wrapper that simulations memory allocation failure or 1765** tracks memory usage, for example. </dd> 1766** 1767** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1768** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1769** type int, interpreted as a boolean, which if true provides a hint to 1770** SQLite that it should avoid large memory allocations if possible. 1771** SQLite will run faster if it is free to make large memory allocations, 1772** but some application might prefer to run slower in exchange for 1773** guarantees about memory fragmentation that are possible if large 1774** allocations are avoided. This hint is normally off. 1775** </dd> 1776** 1777** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1778** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1779** interpreted as a boolean, which enables or disables the collection of 1780** memory allocation statistics. ^(When memory allocation statistics are 1781** disabled, the following SQLite interfaces become non-operational: 1782** <ul> 1783** <li> [sqlite3_hard_heap_limit64()] 1784** <li> [sqlite3_memory_used()] 1785** <li> [sqlite3_memory_highwater()] 1786** <li> [sqlite3_soft_heap_limit64()] 1787** <li> [sqlite3_status64()] 1788** </ul>)^ 1789** ^Memory allocation statistics are enabled by default unless SQLite is 1790** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1791** allocation statistics are disabled by default. 1792** </dd> 1793** 1794** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1795** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1796** </dd> 1797** 1798** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1799** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1800** that SQLite can use for the database page cache with the default page 1801** cache implementation. 1802** This configuration option is a no-op if an application-defined page 1803** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1804** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1805** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1806** and the number of cache lines (N). 1807** The sz argument should be the size of the largest database page 1808** (a power of two between 512 and 65536) plus some extra bytes for each 1809** page header. ^The number of extra bytes needed by the page header 1810** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1811** ^It is harmless, apart from the wasted memory, 1812** for the sz parameter to be larger than necessary. The pMem 1813** argument must be either a NULL pointer or a pointer to an 8-byte 1814** aligned block of memory of at least sz*N bytes, otherwise 1815** subsequent behavior is undefined. 1816** ^When pMem is not NULL, SQLite will strive to use the memory provided 1817** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1818** a page cache line is larger than sz bytes or if all of the pMem buffer 1819** is exhausted. 1820** ^If pMem is NULL and N is non-zero, then each database connection 1821** does an initial bulk allocation for page cache memory 1822** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1823** of -1024*N bytes if N is negative, . ^If additional 1824** page cache memory is needed beyond what is provided by the initial 1825** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1826** additional cache line. </dd> 1827** 1828** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1829** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1830** that SQLite will use for all of its dynamic memory allocation needs 1831** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1832** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1833** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1834** [SQLITE_ERROR] if invoked otherwise. 1835** ^There are three arguments to SQLITE_CONFIG_HEAP: 1836** An 8-byte aligned pointer to the memory, 1837** the number of bytes in the memory buffer, and the minimum allocation size. 1838** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1839** to using its default memory allocator (the system malloc() implementation), 1840** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1841** memory pointer is not NULL then the alternative memory 1842** allocator is engaged to handle all of SQLites memory allocation needs. 1843** The first pointer (the memory pointer) must be aligned to an 8-byte 1844** boundary or subsequent behavior of SQLite will be undefined. 1845** The minimum allocation size is capped at 2**12. Reasonable values 1846** for the minimum allocation size are 2**5 through 2**8.</dd> 1847** 1848** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1849** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1850** pointer to an instance of the [sqlite3_mutex_methods] structure. 1851** The argument specifies alternative low-level mutex routines to be used 1852** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1853** the content of the [sqlite3_mutex_methods] structure before the call to 1854** [sqlite3_config()] returns. ^If SQLite is compiled with 1855** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1856** the entire mutexing subsystem is omitted from the build and hence calls to 1857** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1858** return [SQLITE_ERROR].</dd> 1859** 1860** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1861** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1862** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1863** [sqlite3_mutex_methods] 1864** structure is filled with the currently defined mutex routines.)^ 1865** This option can be used to overload the default mutex allocation 1866** routines with a wrapper used to track mutex usage for performance 1867** profiling or testing, for example. ^If SQLite is compiled with 1868** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1869** the entire mutexing subsystem is omitted from the build and hence calls to 1870** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1871** return [SQLITE_ERROR].</dd> 1872** 1873** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1874** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1875** the default size of lookaside memory on each [database connection]. 1876** The first argument is the 1877** size of each lookaside buffer slot and the second is the number of 1878** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1879** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1880** option to [sqlite3_db_config()] can be used to change the lookaside 1881** configuration on individual connections.)^ </dd> 1882** 1883** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1884** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1885** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1886** the interface to a custom page cache implementation.)^ 1887** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1888** 1889** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1890** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1891** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1892** the current page cache implementation into that object.)^ </dd> 1893** 1894** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1895** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1896** global [error log]. 1897** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1898** function with a call signature of void(*)(void*,int,const char*), 1899** and a pointer to void. ^If the function pointer is not NULL, it is 1900** invoked by [sqlite3_log()] to process each logging event. ^If the 1901** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1902** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1903** passed through as the first parameter to the application-defined logger 1904** function whenever that function is invoked. ^The second parameter to 1905** the logger function is a copy of the first parameter to the corresponding 1906** [sqlite3_log()] call and is intended to be a [result code] or an 1907** [extended result code]. ^The third parameter passed to the logger is 1908** log message after formatting via [sqlite3_snprintf()]. 1909** The SQLite logging interface is not reentrant; the logger function 1910** supplied by the application must not invoke any SQLite interface. 1911** In a multi-threaded application, the application-defined logger 1912** function must be threadsafe. </dd> 1913** 1914** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1915** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1916** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1917** then URI handling is globally disabled.)^ ^If URI handling is globally 1918** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1919** [sqlite3_open16()] or 1920** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1921** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1922** connection is opened. ^If it is globally disabled, filenames are 1923** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1924** database connection is opened. ^(By default, URI handling is globally 1925** disabled. The default value may be changed by compiling with the 1926** [SQLITE_USE_URI] symbol defined.)^ 1927** 1928** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1929** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1930** argument which is interpreted as a boolean in order to enable or disable 1931** the use of covering indices for full table scans in the query optimizer. 1932** ^The default setting is determined 1933** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1934** if that compile-time option is omitted. 1935** The ability to disable the use of covering indices for full table scans 1936** is because some incorrectly coded legacy applications might malfunction 1937** when the optimization is enabled. Providing the ability to 1938** disable the optimization allows the older, buggy application code to work 1939** without change even with newer versions of SQLite. 1940** 1941** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1942** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1943** <dd> These options are obsolete and should not be used by new code. 1944** They are retained for backwards compatibility but are now no-ops. 1945** </dd> 1946** 1947** [[SQLITE_CONFIG_SQLLOG]] 1948** <dt>SQLITE_CONFIG_SQLLOG 1949** <dd>This option is only available if sqlite is compiled with the 1950** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1951** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1952** The second should be of type (void*). The callback is invoked by the library 1953** in three separate circumstances, identified by the value passed as the 1954** fourth parameter. If the fourth parameter is 0, then the database connection 1955** passed as the second argument has just been opened. The third argument 1956** points to a buffer containing the name of the main database file. If the 1957** fourth parameter is 1, then the SQL statement that the third parameter 1958** points to has just been executed. Or, if the fourth parameter is 2, then 1959** the connection being passed as the second parameter is being closed. The 1960** third parameter is passed NULL In this case. An example of using this 1961** configuration option can be seen in the "test_sqllog.c" source file in 1962** the canonical SQLite source tree.</dd> 1963** 1964** [[SQLITE_CONFIG_MMAP_SIZE]] 1965** <dt>SQLITE_CONFIG_MMAP_SIZE 1966** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1967** that are the default mmap size limit (the default setting for 1968** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1969** ^The default setting can be overridden by each database connection using 1970** either the [PRAGMA mmap_size] command, or by using the 1971** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1972** will be silently truncated if necessary so that it does not exceed the 1973** compile-time maximum mmap size set by the 1974** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1975** ^If either argument to this option is negative, then that argument is 1976** changed to its compile-time default. 1977** 1978** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1979** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1980** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1981** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1982** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1983** that specifies the maximum size of the created heap. 1984** 1985** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1986** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1987** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1988** is a pointer to an integer and writes into that integer the number of extra 1989** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1990** The amount of extra space required can change depending on the compiler, 1991** target platform, and SQLite version. 1992** 1993** [[SQLITE_CONFIG_PMASZ]] 1994** <dt>SQLITE_CONFIG_PMASZ 1995** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1996** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1997** sorter to that integer. The default minimum PMA Size is set by the 1998** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1999** to help with sort operations when multithreaded sorting 2000** is enabled (using the [PRAGMA threads] command) and the amount of content 2001** to be sorted exceeds the page size times the minimum of the 2002** [PRAGMA cache_size] setting and this value. 2003** 2004** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 2005** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 2006** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 2007** becomes the [statement journal] spill-to-disk threshold. 2008** [Statement journals] are held in memory until their size (in bytes) 2009** exceeds this threshold, at which point they are written to disk. 2010** Or if the threshold is -1, statement journals are always held 2011** exclusively in memory. 2012** Since many statement journals never become large, setting the spill 2013** threshold to a value such as 64KiB can greatly reduce the amount of 2014** I/O required to support statement rollback. 2015** The default value for this setting is controlled by the 2016** [SQLITE_STMTJRNL_SPILL] compile-time option. 2017** 2018** [[SQLITE_CONFIG_SORTERREF_SIZE]] 2019** <dt>SQLITE_CONFIG_SORTERREF_SIZE 2020** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter 2021** of type (int) - the new value of the sorter-reference size threshold. 2022** Usually, when SQLite uses an external sort to order records according 2023** to an ORDER BY clause, all fields required by the caller are present in the 2024** sorted records. However, if SQLite determines based on the declared type 2025** of a table column that its values are likely to be very large - larger 2026** than the configured sorter-reference size threshold - then a reference 2027** is stored in each sorted record and the required column values loaded 2028** from the database as records are returned in sorted order. The default 2029** value for this option is to never use this optimization. Specifying a 2030** negative value for this option restores the default behaviour. 2031** This option is only available if SQLite is compiled with the 2032** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option. 2033** 2034** [[SQLITE_CONFIG_MEMDB_MAXSIZE]] 2035** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE 2036** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter 2037** [sqlite3_int64] parameter which is the default maximum size for an in-memory 2038** database created using [sqlite3_deserialize()]. This default maximum 2039** size can be adjusted up or down for individual databases using the 2040** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control]. If this 2041** configuration setting is never used, then the default maximum is determined 2042** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option. If that 2043** compile-time option is not set, then the default maximum is 1073741824. 2044** </dl> 2045*/ 2046#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 2047#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 2048#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 2049#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 2050#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 2051#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 2052#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 2053#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 2054#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 2055#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 2056#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 2057/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 2058#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 2059#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 2060#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 2061#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 2062#define SQLITE_CONFIG_URI 17 /* int */ 2063#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 2064#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 2065#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 2066#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 2067#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 2068#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 2069#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 2070#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 2071#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 2072#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 2073#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */ 2074#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */ 2075 2076/* 2077** CAPI3REF: Database Connection Configuration Options 2078** 2079** These constants are the available integer configuration options that 2080** can be passed as the second argument to the [sqlite3_db_config()] interface. 2081** 2082** New configuration options may be added in future releases of SQLite. 2083** Existing configuration options might be discontinued. Applications 2084** should check the return code from [sqlite3_db_config()] to make sure that 2085** the call worked. ^The [sqlite3_db_config()] interface will return a 2086** non-zero [error code] if a discontinued or unsupported configuration option 2087** is invoked. 2088** 2089** <dl> 2090** [[SQLITE_DBCONFIG_LOOKASIDE]] 2091** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 2092** <dd> ^This option takes three additional arguments that determine the 2093** [lookaside memory allocator] configuration for the [database connection]. 2094** ^The first argument (the third parameter to [sqlite3_db_config()] is a 2095** pointer to a memory buffer to use for lookaside memory. 2096** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 2097** may be NULL in which case SQLite will allocate the 2098** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 2099** size of each lookaside buffer slot. ^The third argument is the number of 2100** slots. The size of the buffer in the first argument must be greater than 2101** or equal to the product of the second and third arguments. The buffer 2102** must be aligned to an 8-byte boundary. ^If the second argument to 2103** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 2104** rounded down to the next smaller multiple of 8. ^(The lookaside memory 2105** configuration for a database connection can only be changed when that 2106** connection is not currently using lookaside memory, or in other words 2107** when the "current value" returned by 2108** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 2109** Any attempt to change the lookaside memory configuration when lookaside 2110** memory is in use leaves the configuration unchanged and returns 2111** [SQLITE_BUSY].)^</dd> 2112** 2113** [[SQLITE_DBCONFIG_ENABLE_FKEY]] 2114** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 2115** <dd> ^This option is used to enable or disable the enforcement of 2116** [foreign key constraints]. There should be two additional arguments. 2117** The first argument is an integer which is 0 to disable FK enforcement, 2118** positive to enable FK enforcement or negative to leave FK enforcement 2119** unchanged. The second parameter is a pointer to an integer into which 2120** is written 0 or 1 to indicate whether FK enforcement is off or on 2121** following this call. The second parameter may be a NULL pointer, in 2122** which case the FK enforcement setting is not reported back. </dd> 2123** 2124** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]] 2125** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2126** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2127** There should be two additional arguments. 2128** The first argument is an integer which is 0 to disable triggers, 2129** positive to enable triggers or negative to leave the setting unchanged. 2130** The second parameter is a pointer to an integer into which 2131** is written 0 or 1 to indicate whether triggers are disabled or enabled 2132** following this call. The second parameter may be a NULL pointer, in 2133** which case the trigger setting is not reported back. 2134** 2135** <p>Originally this option disabled all triggers. ^(However, since 2136** SQLite version 3.35.0, TEMP triggers are still allowed even if 2137** this option is off. So, in other words, this option now only disables 2138** triggers in the main database schema or in the schemas of ATTACH-ed 2139** databases.)^ </dd> 2140** 2141** [[SQLITE_DBCONFIG_ENABLE_VIEW]] 2142** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt> 2143** <dd> ^This option is used to enable or disable [CREATE VIEW | views]. 2144** There should be two additional arguments. 2145** The first argument is an integer which is 0 to disable views, 2146** positive to enable views or negative to leave the setting unchanged. 2147** The second parameter is a pointer to an integer into which 2148** is written 0 or 1 to indicate whether views are disabled or enabled 2149** following this call. The second parameter may be a NULL pointer, in 2150** which case the view setting is not reported back. 2151** 2152** <p>Originally this option disabled all views. ^(However, since 2153** SQLite version 3.35.0, TEMP views are still allowed even if 2154** this option is off. So, in other words, this option now only disables 2155** views in the main database schema or in the schemas of ATTACH-ed 2156** databases.)^ </dd> 2157** 2158** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]] 2159** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2160** <dd> ^This option is used to enable or disable the 2161** [fts3_tokenizer()] function which is part of the 2162** [FTS3] full-text search engine extension. 2163** There should be two additional arguments. 2164** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2165** positive to enable fts3_tokenizer() or negative to leave the setting 2166** unchanged. 2167** The second parameter is a pointer to an integer into which 2168** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2169** following this call. The second parameter may be a NULL pointer, in 2170** which case the new setting is not reported back. </dd> 2171** 2172** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]] 2173** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2174** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2175** interface independently of the [load_extension()] SQL function. 2176** The [sqlite3_enable_load_extension()] API enables or disables both the 2177** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2178** There should be two additional arguments. 2179** When the first argument to this interface is 1, then only the C-API is 2180** enabled and the SQL function remains disabled. If the first argument to 2181** this interface is 0, then both the C-API and the SQL function are disabled. 2182** If the first argument is -1, then no changes are made to state of either the 2183** C-API or the SQL function. 2184** The second parameter is a pointer to an integer into which 2185** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2186** is disabled or enabled following this call. The second parameter may 2187** be a NULL pointer, in which case the new setting is not reported back. 2188** </dd> 2189** 2190** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2191** <dd> ^This option is used to change the name of the "main" database 2192** schema. ^The sole argument is a pointer to a constant UTF8 string 2193** which will become the new schema name in place of "main". ^SQLite 2194** does not make a copy of the new main schema name string, so the application 2195** must ensure that the argument passed into this DBCONFIG option is unchanged 2196** until after the database connection closes. 2197** </dd> 2198** 2199** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]] 2200** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2201** <dd> Usually, when a database in wal mode is closed or detached from a 2202** database handle, SQLite checks if this will mean that there are now no 2203** connections at all to the database. If so, it performs a checkpoint 2204** operation before closing the connection. This option may be used to 2205** override this behaviour. The first parameter passed to this operation 2206** is an integer - positive to disable checkpoints-on-close, or zero (the 2207** default) to enable them, and negative to leave the setting unchanged. 2208** The second parameter is a pointer to an integer 2209** into which is written 0 or 1 to indicate whether checkpoints-on-close 2210** have been disabled - 0 if they are not disabled, 1 if they are. 2211** </dd> 2212** 2213** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2214** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2215** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2216** a single SQL query statement will always use the same algorithm regardless 2217** of values of [bound parameters].)^ The QPSG disables some query optimizations 2218** that look at the values of bound parameters, which can make some queries 2219** slower. But the QPSG has the advantage of more predictable behavior. With 2220** the QPSG active, SQLite will always use the same query plan in the field as 2221** was used during testing in the lab. 2222** The first argument to this setting is an integer which is 0 to disable 2223** the QPSG, positive to enable QPSG, or negative to leave the setting 2224** unchanged. The second parameter is a pointer to an integer into which 2225** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2226** following this call. 2227** </dd> 2228** 2229** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2230** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2231** include output for any operations performed by trigger programs. This 2232** option is used to set or clear (the default) a flag that governs this 2233** behavior. The first parameter passed to this operation is an integer - 2234** positive to enable output for trigger programs, or zero to disable it, 2235** or negative to leave the setting unchanged. 2236** The second parameter is a pointer to an integer into which is written 2237** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2238** it is not disabled, 1 if it is. 2239** </dd> 2240** 2241** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt> 2242** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run 2243** [VACUUM] in order to reset a database back to an empty database 2244** with no schema and no content. The following process works even for 2245** a badly corrupted database file: 2246** <ol> 2247** <li> If the database connection is newly opened, make sure it has read the 2248** database schema by preparing then discarding some query against the 2249** database, or calling sqlite3_table_column_metadata(), ignoring any 2250** errors. This step is only necessary if the application desires to keep 2251** the database in WAL mode after the reset if it was in WAL mode before 2252** the reset. 2253** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0); 2254** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0); 2255** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0); 2256** </ol> 2257** Because resetting a database is destructive and irreversible, the 2258** process requires the use of this obscure API and multiple steps to help 2259** ensure that it does not happen by accident. 2260** 2261** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt> 2262** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the 2263** "defensive" flag for a database connection. When the defensive 2264** flag is enabled, language features that allow ordinary SQL to 2265** deliberately corrupt the database file are disabled. The disabled 2266** features include but are not limited to the following: 2267** <ul> 2268** <li> The [PRAGMA writable_schema=ON] statement. 2269** <li> The [PRAGMA journal_mode=OFF] statement. 2270** <li> Writes to the [sqlite_dbpage] virtual table. 2271** <li> Direct writes to [shadow tables]. 2272** </ul> 2273** </dd> 2274** 2275** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt> 2276** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the 2277** "writable_schema" flag. This has the same effect and is logically equivalent 2278** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF]. 2279** The first argument to this setting is an integer which is 0 to disable 2280** the writable_schema, positive to enable writable_schema, or negative to 2281** leave the setting unchanged. The second parameter is a pointer to an 2282** integer into which is written 0 or 1 to indicate whether the writable_schema 2283** is enabled or disabled following this call. 2284** </dd> 2285** 2286** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]] 2287** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt> 2288** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates 2289** the legacy behavior of the [ALTER TABLE RENAME] command such it 2290** behaves as it did prior to [version 3.24.0] (2018-06-04). See the 2291** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for 2292** additional information. This feature can also be turned on and off 2293** using the [PRAGMA legacy_alter_table] statement. 2294** </dd> 2295** 2296** [[SQLITE_DBCONFIG_DQS_DML]] 2297** <dt>SQLITE_DBCONFIG_DQS_DML</td> 2298** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates 2299** the legacy [double-quoted string literal] misfeature for DML statements 2300** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The 2301** default value of this setting is determined by the [-DSQLITE_DQS] 2302** compile-time option. 2303** </dd> 2304** 2305** [[SQLITE_DBCONFIG_DQS_DDL]] 2306** <dt>SQLITE_DBCONFIG_DQS_DDL</td> 2307** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates 2308** the legacy [double-quoted string literal] misfeature for DDL statements, 2309** such as CREATE TABLE and CREATE INDEX. The 2310** default value of this setting is determined by the [-DSQLITE_DQS] 2311** compile-time option. 2312** </dd> 2313** 2314** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]] 2315** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td> 2316** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to 2317** assume that database schemas are untainted by malicious content. 2318** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite 2319** takes additional defensive steps to protect the application from harm 2320** including: 2321** <ul> 2322** <li> Prohibit the use of SQL functions inside triggers, views, 2323** CHECK constraints, DEFAULT clauses, expression indexes, 2324** partial indexes, or generated columns 2325** unless those functions are tagged with [SQLITE_INNOCUOUS]. 2326** <li> Prohibit the use of virtual tables inside of triggers or views 2327** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS]. 2328** </ul> 2329** This setting defaults to "on" for legacy compatibility, however 2330** all applications are advised to turn it off if possible. This setting 2331** can also be controlled using the [PRAGMA trusted_schema] statement. 2332** </dd> 2333** 2334** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]] 2335** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td> 2336** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates 2337** the legacy file format flag. When activated, this flag causes all newly 2338** created database file to have a schema format version number (the 4-byte 2339** integer found at offset 44 into the database header) of 1. This in turn 2340** means that the resulting database file will be readable and writable by 2341** any SQLite version back to 3.0.0 ([dateof:3.0.0]). Without this setting, 2342** newly created databases are generally not understandable by SQLite versions 2343** prior to 3.3.0 ([dateof:3.3.0]). As these words are written, there 2344** is now scarcely any need to generated database files that are compatible 2345** all the way back to version 3.0.0, and so this setting is of little 2346** practical use, but is provided so that SQLite can continue to claim the 2347** ability to generate new database files that are compatible with version 2348** 3.0.0. 2349** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on, 2350** the [VACUUM] command will fail with an obscure error when attempting to 2351** process a table with generated columns and a descending index. This is 2352** not considered a bug since SQLite versions 3.3.0 and earlier do not support 2353** either generated columns or decending indexes. 2354** </dd> 2355** </dl> 2356*/ 2357#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2358#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2359#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2360#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2361#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2362#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2363#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2364#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2365#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2366#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */ 2367#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */ 2368#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */ 2369#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */ 2370#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */ 2371#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */ 2372#define SQLITE_DBCONFIG_ENABLE_VIEW 1015 /* int int* */ 2373#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT 1016 /* int int* */ 2374#define SQLITE_DBCONFIG_TRUSTED_SCHEMA 1017 /* int int* */ 2375#define SQLITE_DBCONFIG_MAX 1017 /* Largest DBCONFIG */ 2376 2377/* 2378** CAPI3REF: Enable Or Disable Extended Result Codes 2379** METHOD: sqlite3 2380** 2381** ^The sqlite3_extended_result_codes() routine enables or disables the 2382** [extended result codes] feature of SQLite. ^The extended result 2383** codes are disabled by default for historical compatibility. 2384*/ 2385int sqlite3_extended_result_codes(sqlite3*, int onoff); 2386 2387/* 2388** CAPI3REF: Last Insert Rowid 2389** METHOD: sqlite3 2390** 2391** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2392** has a unique 64-bit signed 2393** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2394** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2395** names are not also used by explicitly declared columns. ^If 2396** the table has a column of type [INTEGER PRIMARY KEY] then that column 2397** is another alias for the rowid. 2398** 2399** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2400** the most recent successful [INSERT] into a rowid table or [virtual table] 2401** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2402** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2403** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2404** zero. 2405** 2406** As well as being set automatically as rows are inserted into database 2407** tables, the value returned by this function may be set explicitly by 2408** [sqlite3_set_last_insert_rowid()] 2409** 2410** Some virtual table implementations may INSERT rows into rowid tables as 2411** part of committing a transaction (e.g. to flush data accumulated in memory 2412** to disk). In this case subsequent calls to this function return the rowid 2413** associated with these internal INSERT operations, which leads to 2414** unintuitive results. Virtual table implementations that do write to rowid 2415** tables in this way can avoid this problem by restoring the original 2416** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2417** control to the user. 2418** 2419** ^(If an [INSERT] occurs within a trigger then this routine will 2420** return the [rowid] of the inserted row as long as the trigger is 2421** running. Once the trigger program ends, the value returned 2422** by this routine reverts to what it was before the trigger was fired.)^ 2423** 2424** ^An [INSERT] that fails due to a constraint violation is not a 2425** successful [INSERT] and does not change the value returned by this 2426** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2427** and INSERT OR ABORT make no changes to the return value of this 2428** routine when their insertion fails. ^(When INSERT OR REPLACE 2429** encounters a constraint violation, it does not fail. The 2430** INSERT continues to completion after deleting rows that caused 2431** the constraint problem so INSERT OR REPLACE will always change 2432** the return value of this interface.)^ 2433** 2434** ^For the purposes of this routine, an [INSERT] is considered to 2435** be successful even if it is subsequently rolled back. 2436** 2437** This function is accessible to SQL statements via the 2438** [last_insert_rowid() SQL function]. 2439** 2440** If a separate thread performs a new [INSERT] on the same 2441** database connection while the [sqlite3_last_insert_rowid()] 2442** function is running and thus changes the last insert [rowid], 2443** then the value returned by [sqlite3_last_insert_rowid()] is 2444** unpredictable and might not equal either the old or the new 2445** last insert [rowid]. 2446*/ 2447sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2448 2449/* 2450** CAPI3REF: Set the Last Insert Rowid value. 2451** METHOD: sqlite3 2452** 2453** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2454** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2455** without inserting a row into the database. 2456*/ 2457void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2458 2459/* 2460** CAPI3REF: Count The Number Of Rows Modified 2461** METHOD: sqlite3 2462** 2463** ^This function returns the number of rows modified, inserted or 2464** deleted by the most recently completed INSERT, UPDATE or DELETE 2465** statement on the database connection specified by the only parameter. 2466** ^Executing any other type of SQL statement does not modify the value 2467** returned by this function. 2468** 2469** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2470** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2471** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2472** 2473** Changes to a view that are intercepted by 2474** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2475** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2476** DELETE statement run on a view is always zero. Only changes made to real 2477** tables are counted. 2478** 2479** Things are more complicated if the sqlite3_changes() function is 2480** executed while a trigger program is running. This may happen if the 2481** program uses the [changes() SQL function], or if some other callback 2482** function invokes sqlite3_changes() directly. Essentially: 2483** 2484** <ul> 2485** <li> ^(Before entering a trigger program the value returned by 2486** sqlite3_changes() function is saved. After the trigger program 2487** has finished, the original value is restored.)^ 2488** 2489** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2490** statement sets the value returned by sqlite3_changes() 2491** upon completion as normal. Of course, this value will not include 2492** any changes performed by sub-triggers, as the sqlite3_changes() 2493** value will be saved and restored after each sub-trigger has run.)^ 2494** </ul> 2495** 2496** ^This means that if the changes() SQL function (or similar) is used 2497** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2498** returns the value as set when the calling statement began executing. 2499** ^If it is used by the second or subsequent such statement within a trigger 2500** program, the value returned reflects the number of rows modified by the 2501** previous INSERT, UPDATE or DELETE statement within the same trigger. 2502** 2503** If a separate thread makes changes on the same database connection 2504** while [sqlite3_changes()] is running then the value returned 2505** is unpredictable and not meaningful. 2506** 2507** See also: 2508** <ul> 2509** <li> the [sqlite3_total_changes()] interface 2510** <li> the [count_changes pragma] 2511** <li> the [changes() SQL function] 2512** <li> the [data_version pragma] 2513** </ul> 2514*/ 2515int sqlite3_changes(sqlite3*); 2516 2517/* 2518** CAPI3REF: Total Number Of Rows Modified 2519** METHOD: sqlite3 2520** 2521** ^This function returns the total number of rows inserted, modified or 2522** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2523** since the database connection was opened, including those executed as 2524** part of trigger programs. ^Executing any other type of SQL statement 2525** does not affect the value returned by sqlite3_total_changes(). 2526** 2527** ^Changes made as part of [foreign key actions] are included in the 2528** count, but those made as part of REPLACE constraint resolution are 2529** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2530** are not counted. 2531** 2532** The [sqlite3_total_changes(D)] interface only reports the number 2533** of rows that changed due to SQL statement run against database 2534** connection D. Any changes by other database connections are ignored. 2535** To detect changes against a database file from other database 2536** connections use the [PRAGMA data_version] command or the 2537** [SQLITE_FCNTL_DATA_VERSION] [file control]. 2538** 2539** If a separate thread makes changes on the same database connection 2540** while [sqlite3_total_changes()] is running then the value 2541** returned is unpredictable and not meaningful. 2542** 2543** See also: 2544** <ul> 2545** <li> the [sqlite3_changes()] interface 2546** <li> the [count_changes pragma] 2547** <li> the [changes() SQL function] 2548** <li> the [data_version pragma] 2549** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control] 2550** </ul> 2551*/ 2552int sqlite3_total_changes(sqlite3*); 2553 2554/* 2555** CAPI3REF: Interrupt A Long-Running Query 2556** METHOD: sqlite3 2557** 2558** ^This function causes any pending database operation to abort and 2559** return at its earliest opportunity. This routine is typically 2560** called in response to a user action such as pressing "Cancel" 2561** or Ctrl-C where the user wants a long query operation to halt 2562** immediately. 2563** 2564** ^It is safe to call this routine from a thread different from the 2565** thread that is currently running the database operation. But it 2566** is not safe to call this routine with a [database connection] that 2567** is closed or might close before sqlite3_interrupt() returns. 2568** 2569** ^If an SQL operation is very nearly finished at the time when 2570** sqlite3_interrupt() is called, then it might not have an opportunity 2571** to be interrupted and might continue to completion. 2572** 2573** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2574** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2575** that is inside an explicit transaction, then the entire transaction 2576** will be rolled back automatically. 2577** 2578** ^The sqlite3_interrupt(D) call is in effect until all currently running 2579** SQL statements on [database connection] D complete. ^Any new SQL statements 2580** that are started after the sqlite3_interrupt() call and before the 2581** running statement count reaches zero are interrupted as if they had been 2582** running prior to the sqlite3_interrupt() call. ^New SQL statements 2583** that are started after the running statement count reaches zero are 2584** not effected by the sqlite3_interrupt(). 2585** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2586** SQL statements is a no-op and has no effect on SQL statements 2587** that are started after the sqlite3_interrupt() call returns. 2588*/ 2589void sqlite3_interrupt(sqlite3*); 2590 2591/* 2592** CAPI3REF: Determine If An SQL Statement Is Complete 2593** 2594** These routines are useful during command-line input to determine if the 2595** currently entered text seems to form a complete SQL statement or 2596** if additional input is needed before sending the text into 2597** SQLite for parsing. ^These routines return 1 if the input string 2598** appears to be a complete SQL statement. ^A statement is judged to be 2599** complete if it ends with a semicolon token and is not a prefix of a 2600** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2601** string literals or quoted identifier names or comments are not 2602** independent tokens (they are part of the token in which they are 2603** embedded) and thus do not count as a statement terminator. ^Whitespace 2604** and comments that follow the final semicolon are ignored. 2605** 2606** ^These routines return 0 if the statement is incomplete. ^If a 2607** memory allocation fails, then SQLITE_NOMEM is returned. 2608** 2609** ^These routines do not parse the SQL statements thus 2610** will not detect syntactically incorrect SQL. 2611** 2612** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2613** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2614** automatically by sqlite3_complete16(). If that initialization fails, 2615** then the return value from sqlite3_complete16() will be non-zero 2616** regardless of whether or not the input SQL is complete.)^ 2617** 2618** The input to [sqlite3_complete()] must be a zero-terminated 2619** UTF-8 string. 2620** 2621** The input to [sqlite3_complete16()] must be a zero-terminated 2622** UTF-16 string in native byte order. 2623*/ 2624int sqlite3_complete(const char *sql); 2625int sqlite3_complete16(const void *sql); 2626 2627/* 2628** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2629** KEYWORDS: {busy-handler callback} {busy handler} 2630** METHOD: sqlite3 2631** 2632** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2633** that might be invoked with argument P whenever 2634** an attempt is made to access a database table associated with 2635** [database connection] D when another thread 2636** or process has the table locked. 2637** The sqlite3_busy_handler() interface is used to implement 2638** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2639** 2640** ^If the busy callback is NULL, then [SQLITE_BUSY] 2641** is returned immediately upon encountering the lock. ^If the busy callback 2642** is not NULL, then the callback might be invoked with two arguments. 2643** 2644** ^The first argument to the busy handler is a copy of the void* pointer which 2645** is the third argument to sqlite3_busy_handler(). ^The second argument to 2646** the busy handler callback is the number of times that the busy handler has 2647** been invoked previously for the same locking event. ^If the 2648** busy callback returns 0, then no additional attempts are made to 2649** access the database and [SQLITE_BUSY] is returned 2650** to the application. 2651** ^If the callback returns non-zero, then another attempt 2652** is made to access the database and the cycle repeats. 2653** 2654** The presence of a busy handler does not guarantee that it will be invoked 2655** when there is lock contention. ^If SQLite determines that invoking the busy 2656** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2657** to the application instead of invoking the 2658** busy handler. 2659** Consider a scenario where one process is holding a read lock that 2660** it is trying to promote to a reserved lock and 2661** a second process is holding a reserved lock that it is trying 2662** to promote to an exclusive lock. The first process cannot proceed 2663** because it is blocked by the second and the second process cannot 2664** proceed because it is blocked by the first. If both processes 2665** invoke the busy handlers, neither will make any progress. Therefore, 2666** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2667** will induce the first process to release its read lock and allow 2668** the second process to proceed. 2669** 2670** ^The default busy callback is NULL. 2671** 2672** ^(There can only be a single busy handler defined for each 2673** [database connection]. Setting a new busy handler clears any 2674** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2675** or evaluating [PRAGMA busy_timeout=N] will change the 2676** busy handler and thus clear any previously set busy handler. 2677** 2678** The busy callback should not take any actions which modify the 2679** database connection that invoked the busy handler. In other words, 2680** the busy handler is not reentrant. Any such actions 2681** result in undefined behavior. 2682** 2683** A busy handler must not close the database connection 2684** or [prepared statement] that invoked the busy handler. 2685*/ 2686int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2687 2688/* 2689** CAPI3REF: Set A Busy Timeout 2690** METHOD: sqlite3 2691** 2692** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2693** for a specified amount of time when a table is locked. ^The handler 2694** will sleep multiple times until at least "ms" milliseconds of sleeping 2695** have accumulated. ^After at least "ms" milliseconds of sleeping, 2696** the handler returns 0 which causes [sqlite3_step()] to return 2697** [SQLITE_BUSY]. 2698** 2699** ^Calling this routine with an argument less than or equal to zero 2700** turns off all busy handlers. 2701** 2702** ^(There can only be a single busy handler for a particular 2703** [database connection] at any given moment. If another busy handler 2704** was defined (using [sqlite3_busy_handler()]) prior to calling 2705** this routine, that other busy handler is cleared.)^ 2706** 2707** See also: [PRAGMA busy_timeout] 2708*/ 2709int sqlite3_busy_timeout(sqlite3*, int ms); 2710 2711/* 2712** CAPI3REF: Convenience Routines For Running Queries 2713** METHOD: sqlite3 2714** 2715** This is a legacy interface that is preserved for backwards compatibility. 2716** Use of this interface is not recommended. 2717** 2718** Definition: A <b>result table</b> is memory data structure created by the 2719** [sqlite3_get_table()] interface. A result table records the 2720** complete query results from one or more queries. 2721** 2722** The table conceptually has a number of rows and columns. But 2723** these numbers are not part of the result table itself. These 2724** numbers are obtained separately. Let N be the number of rows 2725** and M be the number of columns. 2726** 2727** A result table is an array of pointers to zero-terminated UTF-8 strings. 2728** There are (N+1)*M elements in the array. The first M pointers point 2729** to zero-terminated strings that contain the names of the columns. 2730** The remaining entries all point to query results. NULL values result 2731** in NULL pointers. All other values are in their UTF-8 zero-terminated 2732** string representation as returned by [sqlite3_column_text()]. 2733** 2734** A result table might consist of one or more memory allocations. 2735** It is not safe to pass a result table directly to [sqlite3_free()]. 2736** A result table should be deallocated using [sqlite3_free_table()]. 2737** 2738** ^(As an example of the result table format, suppose a query result 2739** is as follows: 2740** 2741** <blockquote><pre> 2742** Name | Age 2743** ----------------------- 2744** Alice | 43 2745** Bob | 28 2746** Cindy | 21 2747** </pre></blockquote> 2748** 2749** There are two columns (M==2) and three rows (N==3). Thus the 2750** result table has 8 entries. Suppose the result table is stored 2751** in an array named azResult. Then azResult holds this content: 2752** 2753** <blockquote><pre> 2754** azResult[0] = "Name"; 2755** azResult[1] = "Age"; 2756** azResult[2] = "Alice"; 2757** azResult[3] = "43"; 2758** azResult[4] = "Bob"; 2759** azResult[5] = "28"; 2760** azResult[6] = "Cindy"; 2761** azResult[7] = "21"; 2762** </pre></blockquote>)^ 2763** 2764** ^The sqlite3_get_table() function evaluates one or more 2765** semicolon-separated SQL statements in the zero-terminated UTF-8 2766** string of its 2nd parameter and returns a result table to the 2767** pointer given in its 3rd parameter. 2768** 2769** After the application has finished with the result from sqlite3_get_table(), 2770** it must pass the result table pointer to sqlite3_free_table() in order to 2771** release the memory that was malloced. Because of the way the 2772** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2773** function must not try to call [sqlite3_free()] directly. Only 2774** [sqlite3_free_table()] is able to release the memory properly and safely. 2775** 2776** The sqlite3_get_table() interface is implemented as a wrapper around 2777** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2778** to any internal data structures of SQLite. It uses only the public 2779** interface defined here. As a consequence, errors that occur in the 2780** wrapper layer outside of the internal [sqlite3_exec()] call are not 2781** reflected in subsequent calls to [sqlite3_errcode()] or 2782** [sqlite3_errmsg()]. 2783*/ 2784int sqlite3_get_table( 2785 sqlite3 *db, /* An open database */ 2786 const char *zSql, /* SQL to be evaluated */ 2787 char ***pazResult, /* Results of the query */ 2788 int *pnRow, /* Number of result rows written here */ 2789 int *pnColumn, /* Number of result columns written here */ 2790 char **pzErrmsg /* Error msg written here */ 2791); 2792void sqlite3_free_table(char **result); 2793 2794/* 2795** CAPI3REF: Formatted String Printing Functions 2796** 2797** These routines are work-alikes of the "printf()" family of functions 2798** from the standard C library. 2799** These routines understand most of the common formatting options from 2800** the standard library printf() 2801** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2802** See the [built-in printf()] documentation for details. 2803** 2804** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2805** results into memory obtained from [sqlite3_malloc64()]. 2806** The strings returned by these two routines should be 2807** released by [sqlite3_free()]. ^Both routines return a 2808** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2809** memory to hold the resulting string. 2810** 2811** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2812** the standard C library. The result is written into the 2813** buffer supplied as the second parameter whose size is given by 2814** the first parameter. Note that the order of the 2815** first two parameters is reversed from snprintf().)^ This is an 2816** historical accident that cannot be fixed without breaking 2817** backwards compatibility. ^(Note also that sqlite3_snprintf() 2818** returns a pointer to its buffer instead of the number of 2819** characters actually written into the buffer.)^ We admit that 2820** the number of characters written would be a more useful return 2821** value but we cannot change the implementation of sqlite3_snprintf() 2822** now without breaking compatibility. 2823** 2824** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2825** guarantees that the buffer is always zero-terminated. ^The first 2826** parameter "n" is the total size of the buffer, including space for 2827** the zero terminator. So the longest string that can be completely 2828** written will be n-1 characters. 2829** 2830** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2831** 2832** See also: [built-in printf()], [printf() SQL function] 2833*/ 2834char *sqlite3_mprintf(const char*,...); 2835char *sqlite3_vmprintf(const char*, va_list); 2836char *sqlite3_snprintf(int,char*,const char*, ...); 2837char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2838 2839/* 2840** CAPI3REF: Memory Allocation Subsystem 2841** 2842** The SQLite core uses these three routines for all of its own 2843** internal memory allocation needs. "Core" in the previous sentence 2844** does not include operating-system specific [VFS] implementation. The 2845** Windows VFS uses native malloc() and free() for some operations. 2846** 2847** ^The sqlite3_malloc() routine returns a pointer to a block 2848** of memory at least N bytes in length, where N is the parameter. 2849** ^If sqlite3_malloc() is unable to obtain sufficient free 2850** memory, it returns a NULL pointer. ^If the parameter N to 2851** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2852** a NULL pointer. 2853** 2854** ^The sqlite3_malloc64(N) routine works just like 2855** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2856** of a signed 32-bit integer. 2857** 2858** ^Calling sqlite3_free() with a pointer previously returned 2859** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2860** that it might be reused. ^The sqlite3_free() routine is 2861** a no-op if is called with a NULL pointer. Passing a NULL pointer 2862** to sqlite3_free() is harmless. After being freed, memory 2863** should neither be read nor written. Even reading previously freed 2864** memory might result in a segmentation fault or other severe error. 2865** Memory corruption, a segmentation fault, or other severe error 2866** might result if sqlite3_free() is called with a non-NULL pointer that 2867** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2868** 2869** ^The sqlite3_realloc(X,N) interface attempts to resize a 2870** prior memory allocation X to be at least N bytes. 2871** ^If the X parameter to sqlite3_realloc(X,N) 2872** is a NULL pointer then its behavior is identical to calling 2873** sqlite3_malloc(N). 2874** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2875** negative then the behavior is exactly the same as calling 2876** sqlite3_free(X). 2877** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2878** of at least N bytes in size or NULL if insufficient memory is available. 2879** ^If M is the size of the prior allocation, then min(N,M) bytes 2880** of the prior allocation are copied into the beginning of buffer returned 2881** by sqlite3_realloc(X,N) and the prior allocation is freed. 2882** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2883** prior allocation is not freed. 2884** 2885** ^The sqlite3_realloc64(X,N) interfaces works the same as 2886** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2887** of a 32-bit signed integer. 2888** 2889** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2890** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2891** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2892** ^The value returned by sqlite3_msize(X) might be larger than the number 2893** of bytes requested when X was allocated. ^If X is a NULL pointer then 2894** sqlite3_msize(X) returns zero. If X points to something that is not 2895** the beginning of memory allocation, or if it points to a formerly 2896** valid memory allocation that has now been freed, then the behavior 2897** of sqlite3_msize(X) is undefined and possibly harmful. 2898** 2899** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2900** sqlite3_malloc64(), and sqlite3_realloc64() 2901** is always aligned to at least an 8 byte boundary, or to a 2902** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2903** option is used. 2904** 2905** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2906** must be either NULL or else pointers obtained from a prior 2907** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2908** not yet been released. 2909** 2910** The application must not read or write any part of 2911** a block of memory after it has been released using 2912** [sqlite3_free()] or [sqlite3_realloc()]. 2913*/ 2914void *sqlite3_malloc(int); 2915void *sqlite3_malloc64(sqlite3_uint64); 2916void *sqlite3_realloc(void*, int); 2917void *sqlite3_realloc64(void*, sqlite3_uint64); 2918void sqlite3_free(void*); 2919sqlite3_uint64 sqlite3_msize(void*); 2920 2921/* 2922** CAPI3REF: Memory Allocator Statistics 2923** 2924** SQLite provides these two interfaces for reporting on the status 2925** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2926** routines, which form the built-in memory allocation subsystem. 2927** 2928** ^The [sqlite3_memory_used()] routine returns the number of bytes 2929** of memory currently outstanding (malloced but not freed). 2930** ^The [sqlite3_memory_highwater()] routine returns the maximum 2931** value of [sqlite3_memory_used()] since the high-water mark 2932** was last reset. ^The values returned by [sqlite3_memory_used()] and 2933** [sqlite3_memory_highwater()] include any overhead 2934** added by SQLite in its implementation of [sqlite3_malloc()], 2935** but not overhead added by the any underlying system library 2936** routines that [sqlite3_malloc()] may call. 2937** 2938** ^The memory high-water mark is reset to the current value of 2939** [sqlite3_memory_used()] if and only if the parameter to 2940** [sqlite3_memory_highwater()] is true. ^The value returned 2941** by [sqlite3_memory_highwater(1)] is the high-water mark 2942** prior to the reset. 2943*/ 2944sqlite3_int64 sqlite3_memory_used(void); 2945sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2946 2947/* 2948** CAPI3REF: Pseudo-Random Number Generator 2949** 2950** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2951** select random [ROWID | ROWIDs] when inserting new records into a table that 2952** already uses the largest possible [ROWID]. The PRNG is also used for 2953** the built-in random() and randomblob() SQL functions. This interface allows 2954** applications to access the same PRNG for other purposes. 2955** 2956** ^A call to this routine stores N bytes of randomness into buffer P. 2957** ^The P parameter can be a NULL pointer. 2958** 2959** ^If this routine has not been previously called or if the previous 2960** call had N less than one or a NULL pointer for P, then the PRNG is 2961** seeded using randomness obtained from the xRandomness method of 2962** the default [sqlite3_vfs] object. 2963** ^If the previous call to this routine had an N of 1 or more and a 2964** non-NULL P then the pseudo-randomness is generated 2965** internally and without recourse to the [sqlite3_vfs] xRandomness 2966** method. 2967*/ 2968void sqlite3_randomness(int N, void *P); 2969 2970/* 2971** CAPI3REF: Compile-Time Authorization Callbacks 2972** METHOD: sqlite3 2973** KEYWORDS: {authorizer callback} 2974** 2975** ^This routine registers an authorizer callback with a particular 2976** [database connection], supplied in the first argument. 2977** ^The authorizer callback is invoked as SQL statements are being compiled 2978** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2979** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2980** and [sqlite3_prepare16_v3()]. ^At various 2981** points during the compilation process, as logic is being created 2982** to perform various actions, the authorizer callback is invoked to 2983** see if those actions are allowed. ^The authorizer callback should 2984** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2985** specific action but allow the SQL statement to continue to be 2986** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2987** rejected with an error. ^If the authorizer callback returns 2988** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2989** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2990** the authorizer will fail with an error message. 2991** 2992** When the callback returns [SQLITE_OK], that means the operation 2993** requested is ok. ^When the callback returns [SQLITE_DENY], the 2994** [sqlite3_prepare_v2()] or equivalent call that triggered the 2995** authorizer will fail with an error message explaining that 2996** access is denied. 2997** 2998** ^The first parameter to the authorizer callback is a copy of the third 2999** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 3000** to the callback is an integer [SQLITE_COPY | action code] that specifies 3001** the particular action to be authorized. ^The third through sixth parameters 3002** to the callback are either NULL pointers or zero-terminated strings 3003** that contain additional details about the action to be authorized. 3004** Applications must always be prepared to encounter a NULL pointer in any 3005** of the third through the sixth parameters of the authorization callback. 3006** 3007** ^If the action code is [SQLITE_READ] 3008** and the callback returns [SQLITE_IGNORE] then the 3009** [prepared statement] statement is constructed to substitute 3010** a NULL value in place of the table column that would have 3011** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 3012** return can be used to deny an untrusted user access to individual 3013** columns of a table. 3014** ^When a table is referenced by a [SELECT] but no column values are 3015** extracted from that table (for example in a query like 3016** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 3017** is invoked once for that table with a column name that is an empty string. 3018** ^If the action code is [SQLITE_DELETE] and the callback returns 3019** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 3020** [truncate optimization] is disabled and all rows are deleted individually. 3021** 3022** An authorizer is used when [sqlite3_prepare | preparing] 3023** SQL statements from an untrusted source, to ensure that the SQL statements 3024** do not try to access data they are not allowed to see, or that they do not 3025** try to execute malicious statements that damage the database. For 3026** example, an application may allow a user to enter arbitrary 3027** SQL queries for evaluation by a database. But the application does 3028** not want the user to be able to make arbitrary changes to the 3029** database. An authorizer could then be put in place while the 3030** user-entered SQL is being [sqlite3_prepare | prepared] that 3031** disallows everything except [SELECT] statements. 3032** 3033** Applications that need to process SQL from untrusted sources 3034** might also consider lowering resource limits using [sqlite3_limit()] 3035** and limiting database size using the [max_page_count] [PRAGMA] 3036** in addition to using an authorizer. 3037** 3038** ^(Only a single authorizer can be in place on a database connection 3039** at a time. Each call to sqlite3_set_authorizer overrides the 3040** previous call.)^ ^Disable the authorizer by installing a NULL callback. 3041** The authorizer is disabled by default. 3042** 3043** The authorizer callback must not do anything that will modify 3044** the database connection that invoked the authorizer callback. 3045** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3046** database connections for the meaning of "modify" in this paragraph. 3047** 3048** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 3049** statement might be re-prepared during [sqlite3_step()] due to a 3050** schema change. Hence, the application should ensure that the 3051** correct authorizer callback remains in place during the [sqlite3_step()]. 3052** 3053** ^Note that the authorizer callback is invoked only during 3054** [sqlite3_prepare()] or its variants. Authorization is not 3055** performed during statement evaluation in [sqlite3_step()], unless 3056** as stated in the previous paragraph, sqlite3_step() invokes 3057** sqlite3_prepare_v2() to reprepare a statement after a schema change. 3058*/ 3059int sqlite3_set_authorizer( 3060 sqlite3*, 3061 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 3062 void *pUserData 3063); 3064 3065/* 3066** CAPI3REF: Authorizer Return Codes 3067** 3068** The [sqlite3_set_authorizer | authorizer callback function] must 3069** return either [SQLITE_OK] or one of these two constants in order 3070** to signal SQLite whether or not the action is permitted. See the 3071** [sqlite3_set_authorizer | authorizer documentation] for additional 3072** information. 3073** 3074** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 3075** returned from the [sqlite3_vtab_on_conflict()] interface. 3076*/ 3077#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 3078#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 3079 3080/* 3081** CAPI3REF: Authorizer Action Codes 3082** 3083** The [sqlite3_set_authorizer()] interface registers a callback function 3084** that is invoked to authorize certain SQL statement actions. The 3085** second parameter to the callback is an integer code that specifies 3086** what action is being authorized. These are the integer action codes that 3087** the authorizer callback may be passed. 3088** 3089** These action code values signify what kind of operation is to be 3090** authorized. The 3rd and 4th parameters to the authorization 3091** callback function will be parameters or NULL depending on which of these 3092** codes is used as the second parameter. ^(The 5th parameter to the 3093** authorizer callback is the name of the database ("main", "temp", 3094** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 3095** is the name of the inner-most trigger or view that is responsible for 3096** the access attempt or NULL if this access attempt is directly from 3097** top-level SQL code. 3098*/ 3099/******************************************* 3rd ************ 4th ***********/ 3100#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 3101#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 3102#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 3103#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 3104#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 3105#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 3106#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 3107#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 3108#define SQLITE_DELETE 9 /* Table Name NULL */ 3109#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 3110#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 3111#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 3112#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 3113#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 3114#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 3115#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 3116#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 3117#define SQLITE_INSERT 18 /* Table Name NULL */ 3118#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 3119#define SQLITE_READ 20 /* Table Name Column Name */ 3120#define SQLITE_SELECT 21 /* NULL NULL */ 3121#define SQLITE_TRANSACTION 22 /* Operation NULL */ 3122#define SQLITE_UPDATE 23 /* Table Name Column Name */ 3123#define SQLITE_ATTACH 24 /* Filename NULL */ 3124#define SQLITE_DETACH 25 /* Database Name NULL */ 3125#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 3126#define SQLITE_REINDEX 27 /* Index Name NULL */ 3127#define SQLITE_ANALYZE 28 /* Table Name NULL */ 3128#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 3129#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 3130#define SQLITE_FUNCTION 31 /* NULL Function Name */ 3131#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 3132#define SQLITE_COPY 0 /* No longer used */ 3133#define SQLITE_RECURSIVE 33 /* NULL NULL */ 3134 3135/* 3136** CAPI3REF: Tracing And Profiling Functions 3137** METHOD: sqlite3 3138** 3139** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 3140** instead of the routines described here. 3141** 3142** These routines register callback functions that can be used for 3143** tracing and profiling the execution of SQL statements. 3144** 3145** ^The callback function registered by sqlite3_trace() is invoked at 3146** various times when an SQL statement is being run by [sqlite3_step()]. 3147** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 3148** SQL statement text as the statement first begins executing. 3149** ^(Additional sqlite3_trace() callbacks might occur 3150** as each triggered subprogram is entered. The callbacks for triggers 3151** contain a UTF-8 SQL comment that identifies the trigger.)^ 3152** 3153** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 3154** the length of [bound parameter] expansion in the output of sqlite3_trace(). 3155** 3156** ^The callback function registered by sqlite3_profile() is invoked 3157** as each SQL statement finishes. ^The profile callback contains 3158** the original statement text and an estimate of wall-clock time 3159** of how long that statement took to run. ^The profile callback 3160** time is in units of nanoseconds, however the current implementation 3161** is only capable of millisecond resolution so the six least significant 3162** digits in the time are meaningless. Future versions of SQLite 3163** might provide greater resolution on the profiler callback. Invoking 3164** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the 3165** profile callback. 3166*/ 3167SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 3168 void(*xTrace)(void*,const char*), void*); 3169SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 3170 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 3171 3172/* 3173** CAPI3REF: SQL Trace Event Codes 3174** KEYWORDS: SQLITE_TRACE 3175** 3176** These constants identify classes of events that can be monitored 3177** using the [sqlite3_trace_v2()] tracing logic. The M argument 3178** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 3179** the following constants. ^The first argument to the trace callback 3180** is one of the following constants. 3181** 3182** New tracing constants may be added in future releases. 3183** 3184** ^A trace callback has four arguments: xCallback(T,C,P,X). 3185** ^The T argument is one of the integer type codes above. 3186** ^The C argument is a copy of the context pointer passed in as the 3187** fourth argument to [sqlite3_trace_v2()]. 3188** The P and X arguments are pointers whose meanings depend on T. 3189** 3190** <dl> 3191** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 3192** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 3193** first begins running and possibly at other times during the 3194** execution of the prepared statement, such as at the start of each 3195** trigger subprogram. ^The P argument is a pointer to the 3196** [prepared statement]. ^The X argument is a pointer to a string which 3197** is the unexpanded SQL text of the prepared statement or an SQL comment 3198** that indicates the invocation of a trigger. ^The callback can compute 3199** the same text that would have been returned by the legacy [sqlite3_trace()] 3200** interface by using the X argument when X begins with "--" and invoking 3201** [sqlite3_expanded_sql(P)] otherwise. 3202** 3203** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 3204** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 3205** information as is provided by the [sqlite3_profile()] callback. 3206** ^The P argument is a pointer to the [prepared statement] and the 3207** X argument points to a 64-bit integer which is the estimated of 3208** the number of nanosecond that the prepared statement took to run. 3209** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 3210** 3211** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 3212** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 3213** statement generates a single row of result. 3214** ^The P argument is a pointer to the [prepared statement] and the 3215** X argument is unused. 3216** 3217** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 3218** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 3219** connection closes. 3220** ^The P argument is a pointer to the [database connection] object 3221** and the X argument is unused. 3222** </dl> 3223*/ 3224#define SQLITE_TRACE_STMT 0x01 3225#define SQLITE_TRACE_PROFILE 0x02 3226#define SQLITE_TRACE_ROW 0x04 3227#define SQLITE_TRACE_CLOSE 0x08 3228 3229/* 3230** CAPI3REF: SQL Trace Hook 3231** METHOD: sqlite3 3232** 3233** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3234** function X against [database connection] D, using property mask M 3235** and context pointer P. ^If the X callback is 3236** NULL or if the M mask is zero, then tracing is disabled. The 3237** M argument should be the bitwise OR-ed combination of 3238** zero or more [SQLITE_TRACE] constants. 3239** 3240** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3241** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3242** 3243** ^The X callback is invoked whenever any of the events identified by 3244** mask M occur. ^The integer return value from the callback is currently 3245** ignored, though this may change in future releases. Callback 3246** implementations should return zero to ensure future compatibility. 3247** 3248** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3249** ^The T argument is one of the [SQLITE_TRACE] 3250** constants to indicate why the callback was invoked. 3251** ^The C argument is a copy of the context pointer. 3252** The P and X arguments are pointers whose meanings depend on T. 3253** 3254** The sqlite3_trace_v2() interface is intended to replace the legacy 3255** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3256** are deprecated. 3257*/ 3258int sqlite3_trace_v2( 3259 sqlite3*, 3260 unsigned uMask, 3261 int(*xCallback)(unsigned,void*,void*,void*), 3262 void *pCtx 3263); 3264 3265/* 3266** CAPI3REF: Query Progress Callbacks 3267** METHOD: sqlite3 3268** 3269** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3270** function X to be invoked periodically during long running calls to 3271** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3272** database connection D. An example use for this 3273** interface is to keep a GUI updated during a large query. 3274** 3275** ^The parameter P is passed through as the only parameter to the 3276** callback function X. ^The parameter N is the approximate number of 3277** [virtual machine instructions] that are evaluated between successive 3278** invocations of the callback X. ^If N is less than one then the progress 3279** handler is disabled. 3280** 3281** ^Only a single progress handler may be defined at one time per 3282** [database connection]; setting a new progress handler cancels the 3283** old one. ^Setting parameter X to NULL disables the progress handler. 3284** ^The progress handler is also disabled by setting N to a value less 3285** than 1. 3286** 3287** ^If the progress callback returns non-zero, the operation is 3288** interrupted. This feature can be used to implement a 3289** "Cancel" button on a GUI progress dialog box. 3290** 3291** The progress handler callback must not do anything that will modify 3292** the database connection that invoked the progress handler. 3293** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3294** database connections for the meaning of "modify" in this paragraph. 3295** 3296*/ 3297void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3298 3299/* 3300** CAPI3REF: Opening A New Database Connection 3301** CONSTRUCTOR: sqlite3 3302** 3303** ^These routines open an SQLite database file as specified by the 3304** filename argument. ^The filename argument is interpreted as UTF-8 for 3305** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3306** order for sqlite3_open16(). ^(A [database connection] handle is usually 3307** returned in *ppDb, even if an error occurs. The only exception is that 3308** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3309** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3310** object.)^ ^(If the database is opened (and/or created) successfully, then 3311** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3312** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3313** an English language description of the error following a failure of any 3314** of the sqlite3_open() routines. 3315** 3316** ^The default encoding will be UTF-8 for databases created using 3317** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3318** created using sqlite3_open16() will be UTF-16 in the native byte order. 3319** 3320** Whether or not an error occurs when it is opened, resources 3321** associated with the [database connection] handle should be released by 3322** passing it to [sqlite3_close()] when it is no longer required. 3323** 3324** The sqlite3_open_v2() interface works like sqlite3_open() 3325** except that it accepts two additional parameters for additional control 3326** over the new database connection. ^(The flags parameter to 3327** sqlite3_open_v2() must include, at a minimum, one of the following 3328** three flag combinations:)^ 3329** 3330** <dl> 3331** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3332** <dd>The database is opened in read-only mode. If the database does not 3333** already exist, an error is returned.</dd>)^ 3334** 3335** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3336** <dd>The database is opened for reading and writing if possible, or reading 3337** only if the file is write protected by the operating system. In either 3338** case the database must already exist, otherwise an error is returned.</dd>)^ 3339** 3340** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3341** <dd>The database is opened for reading and writing, and is created if 3342** it does not already exist. This is the behavior that is always used for 3343** sqlite3_open() and sqlite3_open16().</dd>)^ 3344** </dl> 3345** 3346** In addition to the required flags, the following optional flags are 3347** also supported: 3348** 3349** <dl> 3350** ^(<dt>[SQLITE_OPEN_URI]</dt> 3351** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^ 3352** 3353** ^(<dt>[SQLITE_OPEN_MEMORY]</dt> 3354** <dd>The database will be opened as an in-memory database. The database 3355** is named by the "filename" argument for the purposes of cache-sharing, 3356** if shared cache mode is enabled, but the "filename" is otherwise ignored. 3357** </dd>)^ 3358** 3359** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt> 3360** <dd>The new database connection will use the "multi-thread" 3361** [threading mode].)^ This means that separate threads are allowed 3362** to use SQLite at the same time, as long as each thread is using 3363** a different [database connection]. 3364** 3365** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt> 3366** <dd>The new database connection will use the "serialized" 3367** [threading mode].)^ This means the multiple threads can safely 3368** attempt to use the same database connection at the same time. 3369** (Mutexes will block any actual concurrency, but in this mode 3370** there is no harm in trying.) 3371** 3372** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt> 3373** <dd>The database is opened [shared cache] enabled, overriding 3374** the default shared cache setting provided by 3375** [sqlite3_enable_shared_cache()].)^ 3376** 3377** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt> 3378** <dd>The database is opened [shared cache] disabled, overriding 3379** the default shared cache setting provided by 3380** [sqlite3_enable_shared_cache()].)^ 3381** 3382** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt> 3383** <dd>The database filename is not allowed to be a symbolic link</dd> 3384** </dl>)^ 3385** 3386** If the 3rd parameter to sqlite3_open_v2() is not one of the 3387** required combinations shown above optionally combined with other 3388** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3389** then the behavior is undefined. 3390** 3391** ^The fourth parameter to sqlite3_open_v2() is the name of the 3392** [sqlite3_vfs] object that defines the operating system interface that 3393** the new database connection should use. ^If the fourth parameter is 3394** a NULL pointer then the default [sqlite3_vfs] object is used. 3395** 3396** ^If the filename is ":memory:", then a private, temporary in-memory database 3397** is created for the connection. ^This in-memory database will vanish when 3398** the database connection is closed. Future versions of SQLite might 3399** make use of additional special filenames that begin with the ":" character. 3400** It is recommended that when a database filename actually does begin with 3401** a ":" character you should prefix the filename with a pathname such as 3402** "./" to avoid ambiguity. 3403** 3404** ^If the filename is an empty string, then a private, temporary 3405** on-disk database will be created. ^This private database will be 3406** automatically deleted as soon as the database connection is closed. 3407** 3408** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3409** 3410** ^If [URI filename] interpretation is enabled, and the filename argument 3411** begins with "file:", then the filename is interpreted as a URI. ^URI 3412** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3413** set in the third argument to sqlite3_open_v2(), or if it has 3414** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3415** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3416** URI filename interpretation is turned off 3417** by default, but future releases of SQLite might enable URI filename 3418** interpretation by default. See "[URI filenames]" for additional 3419** information. 3420** 3421** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3422** authority, then it must be either an empty string or the string 3423** "localhost". ^If the authority is not an empty string or "localhost", an 3424** error is returned to the caller. ^The fragment component of a URI, if 3425** present, is ignored. 3426** 3427** ^SQLite uses the path component of the URI as the name of the disk file 3428** which contains the database. ^If the path begins with a '/' character, 3429** then it is interpreted as an absolute path. ^If the path does not begin 3430** with a '/' (meaning that the authority section is omitted from the URI) 3431** then the path is interpreted as a relative path. 3432** ^(On windows, the first component of an absolute path 3433** is a drive specification (e.g. "C:").)^ 3434** 3435** [[core URI query parameters]] 3436** The query component of a URI may contain parameters that are interpreted 3437** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3438** SQLite and its built-in [VFSes] interpret the 3439** following query parameters: 3440** 3441** <ul> 3442** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3443** a VFS object that provides the operating system interface that should 3444** be used to access the database file on disk. ^If this option is set to 3445** an empty string the default VFS object is used. ^Specifying an unknown 3446** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3447** present, then the VFS specified by the option takes precedence over 3448** the value passed as the fourth parameter to sqlite3_open_v2(). 3449** 3450** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3451** "rwc", or "memory". Attempting to set it to any other value is 3452** an error)^. 3453** ^If "ro" is specified, then the database is opened for read-only 3454** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3455** third argument to sqlite3_open_v2(). ^If the mode option is set to 3456** "rw", then the database is opened for read-write (but not create) 3457** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3458** been set. ^Value "rwc" is equivalent to setting both 3459** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3460** set to "memory" then a pure [in-memory database] that never reads 3461** or writes from disk is used. ^It is an error to specify a value for 3462** the mode parameter that is less restrictive than that specified by 3463** the flags passed in the third parameter to sqlite3_open_v2(). 3464** 3465** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3466** "private". ^Setting it to "shared" is equivalent to setting the 3467** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3468** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3469** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3470** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3471** a URI filename, its value overrides any behavior requested by setting 3472** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3473** 3474** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3475** [powersafe overwrite] property does or does not apply to the 3476** storage media on which the database file resides. 3477** 3478** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3479** which if set disables file locking in rollback journal modes. This 3480** is useful for accessing a database on a filesystem that does not 3481** support locking. Caution: Database corruption might result if two 3482** or more processes write to the same database and any one of those 3483** processes uses nolock=1. 3484** 3485** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3486** parameter that indicates that the database file is stored on 3487** read-only media. ^When immutable is set, SQLite assumes that the 3488** database file cannot be changed, even by a process with higher 3489** privilege, and so the database is opened read-only and all locking 3490** and change detection is disabled. Caution: Setting the immutable 3491** property on a database file that does in fact change can result 3492** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3493** See also: [SQLITE_IOCAP_IMMUTABLE]. 3494** 3495** </ul> 3496** 3497** ^Specifying an unknown parameter in the query component of a URI is not an 3498** error. Future versions of SQLite might understand additional query 3499** parameters. See "[query parameters with special meaning to SQLite]" for 3500** additional information. 3501** 3502** [[URI filename examples]] <h3>URI filename examples</h3> 3503** 3504** <table border="1" align=center cellpadding=5> 3505** <tr><th> URI filenames <th> Results 3506** <tr><td> file:data.db <td> 3507** Open the file "data.db" in the current directory. 3508** <tr><td> file:/home/fred/data.db<br> 3509** file:///home/fred/data.db <br> 3510** file://localhost/home/fred/data.db <br> <td> 3511** Open the database file "/home/fred/data.db". 3512** <tr><td> file://darkstar/home/fred/data.db <td> 3513** An error. "darkstar" is not a recognized authority. 3514** <tr><td style="white-space:nowrap"> 3515** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3516** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3517** C:. Note that the %20 escaping in this example is not strictly 3518** necessary - space characters can be used literally 3519** in URI filenames. 3520** <tr><td> file:data.db?mode=ro&cache=private <td> 3521** Open file "data.db" in the current directory for read-only access. 3522** Regardless of whether or not shared-cache mode is enabled by 3523** default, use a private cache. 3524** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3525** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3526** that uses dot-files in place of posix advisory locking. 3527** <tr><td> file:data.db?mode=readonly <td> 3528** An error. "readonly" is not a valid option for the "mode" parameter. 3529** Use "ro" instead: "file:data.db?mode=ro". 3530** </table> 3531** 3532** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3533** query components of a URI. A hexadecimal escape sequence consists of a 3534** percent sign - "%" - followed by exactly two hexadecimal digits 3535** specifying an octet value. ^Before the path or query components of a 3536** URI filename are interpreted, they are encoded using UTF-8 and all 3537** hexadecimal escape sequences replaced by a single byte containing the 3538** corresponding octet. If this process generates an invalid UTF-8 encoding, 3539** the results are undefined. 3540** 3541** <b>Note to Windows users:</b> The encoding used for the filename argument 3542** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3543** codepage is currently defined. Filenames containing international 3544** characters must be converted to UTF-8 prior to passing them into 3545** sqlite3_open() or sqlite3_open_v2(). 3546** 3547** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3548** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3549** features that require the use of temporary files may fail. 3550** 3551** See also: [sqlite3_temp_directory] 3552*/ 3553int sqlite3_open( 3554 const char *filename, /* Database filename (UTF-8) */ 3555 sqlite3 **ppDb /* OUT: SQLite db handle */ 3556); 3557int sqlite3_open16( 3558 const void *filename, /* Database filename (UTF-16) */ 3559 sqlite3 **ppDb /* OUT: SQLite db handle */ 3560); 3561int sqlite3_open_v2( 3562 const char *filename, /* Database filename (UTF-8) */ 3563 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3564 int flags, /* Flags */ 3565 const char *zVfs /* Name of VFS module to use */ 3566); 3567 3568/* 3569** CAPI3REF: Obtain Values For URI Parameters 3570** 3571** These are utility routines, useful to [VFS|custom VFS implementations], 3572** that check if a database file was a URI that contained a specific query 3573** parameter, and if so obtains the value of that query parameter. 3574** 3575** The first parameter to these interfaces (hereafter referred to 3576** as F) must be one of: 3577** <ul> 3578** <li> A database filename pointer created by the SQLite core and 3579** passed into the xOpen() method of a VFS implemention, or 3580** <li> A filename obtained from [sqlite3_db_filename()], or 3581** <li> A new filename constructed using [sqlite3_create_filename()]. 3582** </ul> 3583** If the F parameter is not one of the above, then the behavior is 3584** undefined and probably undesirable. Older versions of SQLite were 3585** more tolerant of invalid F parameters than newer versions. 3586** 3587** If F is a suitable filename (as described in the previous paragraph) 3588** and if P is the name of the query parameter, then 3589** sqlite3_uri_parameter(F,P) returns the value of the P 3590** parameter if it exists or a NULL pointer if P does not appear as a 3591** query parameter on F. If P is a query parameter of F and it 3592** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3593** a pointer to an empty string. 3594** 3595** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3596** parameter and returns true (1) or false (0) according to the value 3597** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3598** value of query parameter P is one of "yes", "true", or "on" in any 3599** case or if the value begins with a non-zero number. The 3600** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3601** query parameter P is one of "no", "false", or "off" in any case or 3602** if the value begins with a numeric zero. If P is not a query 3603** parameter on F or if the value of P does not match any of the 3604** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3605** 3606** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3607** 64-bit signed integer and returns that integer, or D if P does not 3608** exist. If the value of P is something other than an integer, then 3609** zero is returned. 3610** 3611** The sqlite3_uri_key(F,N) returns a pointer to the name (not 3612** the value) of the N-th query parameter for filename F, or a NULL 3613** pointer if N is less than zero or greater than the number of query 3614** parameters minus 1. The N value is zero-based so N should be 0 to obtain 3615** the name of the first query parameter, 1 for the second parameter, and 3616** so forth. 3617** 3618** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3619** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3620** is not a database file pathname pointer that the SQLite core passed 3621** into the xOpen VFS method, then the behavior of this routine is undefined 3622** and probably undesirable. 3623** 3624** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F 3625** parameter can also be the name of a rollback journal file or WAL file 3626** in addition to the main database file. Prior to version 3.31.0, these 3627** routines would only work if F was the name of the main database file. 3628** When the F parameter is the name of the rollback journal or WAL file, 3629** it has access to all the same query parameters as were found on the 3630** main database file. 3631** 3632** See the [URI filename] documentation for additional information. 3633*/ 3634const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3635int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3636sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3637const char *sqlite3_uri_key(const char *zFilename, int N); 3638 3639/* 3640** CAPI3REF: Translate filenames 3641** 3642** These routines are available to [VFS|custom VFS implementations] for 3643** translating filenames between the main database file, the journal file, 3644** and the WAL file. 3645** 3646** If F is the name of an sqlite database file, journal file, or WAL file 3647** passed by the SQLite core into the VFS, then sqlite3_filename_database(F) 3648** returns the name of the corresponding database file. 3649** 3650** If F is the name of an sqlite database file, journal file, or WAL file 3651** passed by the SQLite core into the VFS, or if F is a database filename 3652** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F) 3653** returns the name of the corresponding rollback journal file. 3654** 3655** If F is the name of an sqlite database file, journal file, or WAL file 3656** that was passed by the SQLite core into the VFS, or if F is a database 3657** filename obtained from [sqlite3_db_filename()], then 3658** sqlite3_filename_wal(F) returns the name of the corresponding 3659** WAL file. 3660** 3661** In all of the above, if F is not the name of a database, journal or WAL 3662** filename passed into the VFS from the SQLite core and F is not the 3663** return value from [sqlite3_db_filename()], then the result is 3664** undefined and is likely a memory access violation. 3665*/ 3666const char *sqlite3_filename_database(const char*); 3667const char *sqlite3_filename_journal(const char*); 3668const char *sqlite3_filename_wal(const char*); 3669 3670/* 3671** CAPI3REF: Database File Corresponding To A Journal 3672** 3673** ^If X is the name of a rollback or WAL-mode journal file that is 3674** passed into the xOpen method of [sqlite3_vfs], then 3675** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file] 3676** object that represents the main database file. 3677** 3678** This routine is intended for use in custom [VFS] implementations 3679** only. It is not a general-purpose interface. 3680** The argument sqlite3_file_object(X) must be a filename pointer that 3681** has been passed into [sqlite3_vfs].xOpen method where the 3682** flags parameter to xOpen contains one of the bits 3683** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL]. Any other use 3684** of this routine results in undefined and probably undesirable 3685** behavior. 3686*/ 3687sqlite3_file *sqlite3_database_file_object(const char*); 3688 3689/* 3690** CAPI3REF: Create and Destroy VFS Filenames 3691** 3692** These interfces are provided for use by [VFS shim] implementations and 3693** are not useful outside of that context. 3694** 3695** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of 3696** database filename D with corresponding journal file J and WAL file W and 3697** with N URI parameters key/values pairs in the array P. The result from 3698** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that 3699** is safe to pass to routines like: 3700** <ul> 3701** <li> [sqlite3_uri_parameter()], 3702** <li> [sqlite3_uri_boolean()], 3703** <li> [sqlite3_uri_int64()], 3704** <li> [sqlite3_uri_key()], 3705** <li> [sqlite3_filename_database()], 3706** <li> [sqlite3_filename_journal()], or 3707** <li> [sqlite3_filename_wal()]. 3708** </ul> 3709** If a memory allocation error occurs, sqlite3_create_filename() might 3710** return a NULL pointer. The memory obtained from sqlite3_create_filename(X) 3711** must be released by a corresponding call to sqlite3_free_filename(Y). 3712** 3713** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array 3714** of 2*N pointers to strings. Each pair of pointers in this array corresponds 3715** to a key and value for a query parameter. The P parameter may be a NULL 3716** pointer if N is zero. None of the 2*N pointers in the P array may be 3717** NULL pointers and key pointers should not be empty strings. 3718** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may 3719** be NULL pointers, though they can be empty strings. 3720** 3721** The sqlite3_free_filename(Y) routine releases a memory allocation 3722** previously obtained from sqlite3_create_filename(). Invoking 3723** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op. 3724** 3725** If the Y parameter to sqlite3_free_filename(Y) is anything other 3726** than a NULL pointer or a pointer previously acquired from 3727** sqlite3_create_filename(), then bad things such as heap 3728** corruption or segfaults may occur. The value Y should not be 3729** used again after sqlite3_free_filename(Y) has been called. This means 3730** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y, 3731** then the corresponding [sqlite3_module.xClose() method should also be 3732** invoked prior to calling sqlite3_free_filename(Y). 3733*/ 3734char *sqlite3_create_filename( 3735 const char *zDatabase, 3736 const char *zJournal, 3737 const char *zWal, 3738 int nParam, 3739 const char **azParam 3740); 3741void sqlite3_free_filename(char*); 3742 3743/* 3744** CAPI3REF: Error Codes And Messages 3745** METHOD: sqlite3 3746** 3747** ^If the most recent sqlite3_* API call associated with 3748** [database connection] D failed, then the sqlite3_errcode(D) interface 3749** returns the numeric [result code] or [extended result code] for that 3750** API call. 3751** ^The sqlite3_extended_errcode() 3752** interface is the same except that it always returns the 3753** [extended result code] even when extended result codes are 3754** disabled. 3755** 3756** The values returned by sqlite3_errcode() and/or 3757** sqlite3_extended_errcode() might change with each API call. 3758** Except, there are some interfaces that are guaranteed to never 3759** change the value of the error code. The error-code preserving 3760** interfaces are: 3761** 3762** <ul> 3763** <li> sqlite3_errcode() 3764** <li> sqlite3_extended_errcode() 3765** <li> sqlite3_errmsg() 3766** <li> sqlite3_errmsg16() 3767** </ul> 3768** 3769** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3770** text that describes the error, as either UTF-8 or UTF-16 respectively. 3771** ^(Memory to hold the error message string is managed internally. 3772** The application does not need to worry about freeing the result. 3773** However, the error string might be overwritten or deallocated by 3774** subsequent calls to other SQLite interface functions.)^ 3775** 3776** ^The sqlite3_errstr() interface returns the English-language text 3777** that describes the [result code], as UTF-8. 3778** ^(Memory to hold the error message string is managed internally 3779** and must not be freed by the application)^. 3780** 3781** When the serialized [threading mode] is in use, it might be the 3782** case that a second error occurs on a separate thread in between 3783** the time of the first error and the call to these interfaces. 3784** When that happens, the second error will be reported since these 3785** interfaces always report the most recent result. To avoid 3786** this, each thread can obtain exclusive use of the [database connection] D 3787** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3788** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3789** all calls to the interfaces listed here are completed. 3790** 3791** If an interface fails with SQLITE_MISUSE, that means the interface 3792** was invoked incorrectly by the application. In that case, the 3793** error code and message may or may not be set. 3794*/ 3795int sqlite3_errcode(sqlite3 *db); 3796int sqlite3_extended_errcode(sqlite3 *db); 3797const char *sqlite3_errmsg(sqlite3*); 3798const void *sqlite3_errmsg16(sqlite3*); 3799const char *sqlite3_errstr(int); 3800 3801/* 3802** CAPI3REF: Prepared Statement Object 3803** KEYWORDS: {prepared statement} {prepared statements} 3804** 3805** An instance of this object represents a single SQL statement that 3806** has been compiled into binary form and is ready to be evaluated. 3807** 3808** Think of each SQL statement as a separate computer program. The 3809** original SQL text is source code. A prepared statement object 3810** is the compiled object code. All SQL must be converted into a 3811** prepared statement before it can be run. 3812** 3813** The life-cycle of a prepared statement object usually goes like this: 3814** 3815** <ol> 3816** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3817** <li> Bind values to [parameters] using the sqlite3_bind_*() 3818** interfaces. 3819** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3820** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3821** to step 2. Do this zero or more times. 3822** <li> Destroy the object using [sqlite3_finalize()]. 3823** </ol> 3824*/ 3825typedef struct sqlite3_stmt sqlite3_stmt; 3826 3827/* 3828** CAPI3REF: Run-time Limits 3829** METHOD: sqlite3 3830** 3831** ^(This interface allows the size of various constructs to be limited 3832** on a connection by connection basis. The first parameter is the 3833** [database connection] whose limit is to be set or queried. The 3834** second parameter is one of the [limit categories] that define a 3835** class of constructs to be size limited. The third parameter is the 3836** new limit for that construct.)^ 3837** 3838** ^If the new limit is a negative number, the limit is unchanged. 3839** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3840** [limits | hard upper bound] 3841** set at compile-time by a C preprocessor macro called 3842** [limits | SQLITE_MAX_<i>NAME</i>]. 3843** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3844** ^Attempts to increase a limit above its hard upper bound are 3845** silently truncated to the hard upper bound. 3846** 3847** ^Regardless of whether or not the limit was changed, the 3848** [sqlite3_limit()] interface returns the prior value of the limit. 3849** ^Hence, to find the current value of a limit without changing it, 3850** simply invoke this interface with the third parameter set to -1. 3851** 3852** Run-time limits are intended for use in applications that manage 3853** both their own internal database and also databases that are controlled 3854** by untrusted external sources. An example application might be a 3855** web browser that has its own databases for storing history and 3856** separate databases controlled by JavaScript applications downloaded 3857** off the Internet. The internal databases can be given the 3858** large, default limits. Databases managed by external sources can 3859** be given much smaller limits designed to prevent a denial of service 3860** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3861** interface to further control untrusted SQL. The size of the database 3862** created by an untrusted script can be contained using the 3863** [max_page_count] [PRAGMA]. 3864** 3865** New run-time limit categories may be added in future releases. 3866*/ 3867int sqlite3_limit(sqlite3*, int id, int newVal); 3868 3869/* 3870** CAPI3REF: Run-Time Limit Categories 3871** KEYWORDS: {limit category} {*limit categories} 3872** 3873** These constants define various performance limits 3874** that can be lowered at run-time using [sqlite3_limit()]. 3875** The synopsis of the meanings of the various limits is shown below. 3876** Additional information is available at [limits | Limits in SQLite]. 3877** 3878** <dl> 3879** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3880** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3881** 3882** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3883** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3884** 3885** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3886** <dd>The maximum number of columns in a table definition or in the 3887** result set of a [SELECT] or the maximum number of columns in an index 3888** or in an ORDER BY or GROUP BY clause.</dd>)^ 3889** 3890** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3891** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3892** 3893** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3894** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3895** 3896** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3897** <dd>The maximum number of instructions in a virtual machine program 3898** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3899** the equivalent tries to allocate space for more than this many opcodes 3900** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3901** 3902** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3903** <dd>The maximum number of arguments on a function.</dd>)^ 3904** 3905** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3906** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3907** 3908** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3909** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3910** <dd>The maximum length of the pattern argument to the [LIKE] or 3911** [GLOB] operators.</dd>)^ 3912** 3913** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3914** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3915** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3916** 3917** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3918** <dd>The maximum depth of recursion for triggers.</dd>)^ 3919** 3920** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3921** <dd>The maximum number of auxiliary worker threads that a single 3922** [prepared statement] may start.</dd>)^ 3923** </dl> 3924*/ 3925#define SQLITE_LIMIT_LENGTH 0 3926#define SQLITE_LIMIT_SQL_LENGTH 1 3927#define SQLITE_LIMIT_COLUMN 2 3928#define SQLITE_LIMIT_EXPR_DEPTH 3 3929#define SQLITE_LIMIT_COMPOUND_SELECT 4 3930#define SQLITE_LIMIT_VDBE_OP 5 3931#define SQLITE_LIMIT_FUNCTION_ARG 6 3932#define SQLITE_LIMIT_ATTACHED 7 3933#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3934#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3935#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3936#define SQLITE_LIMIT_WORKER_THREADS 11 3937 3938/* 3939** CAPI3REF: Prepare Flags 3940** 3941** These constants define various flags that can be passed into 3942** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3943** [sqlite3_prepare16_v3()] interfaces. 3944** 3945** New flags may be added in future releases of SQLite. 3946** 3947** <dl> 3948** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3949** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3950** that the prepared statement will be retained for a long time and 3951** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3952** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3953** be used just once or at most a few times and then destroyed using 3954** [sqlite3_finalize()] relatively soon. The current implementation acts 3955** on this hint by avoiding the use of [lookaside memory] so as not to 3956** deplete the limited store of lookaside memory. Future versions of 3957** SQLite may act on this hint differently. 3958** 3959** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt> 3960** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used 3961** to be required for any prepared statement that wanted to use the 3962** [sqlite3_normalized_sql()] interface. However, the 3963** [sqlite3_normalized_sql()] interface is now available to all 3964** prepared statements, regardless of whether or not they use this 3965** flag. 3966** 3967** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt> 3968** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler 3969** to return an error (error code SQLITE_ERROR) if the statement uses 3970** any virtual tables. 3971** </dl> 3972*/ 3973#define SQLITE_PREPARE_PERSISTENT 0x01 3974#define SQLITE_PREPARE_NORMALIZE 0x02 3975#define SQLITE_PREPARE_NO_VTAB 0x04 3976 3977/* 3978** CAPI3REF: Compiling An SQL Statement 3979** KEYWORDS: {SQL statement compiler} 3980** METHOD: sqlite3 3981** CONSTRUCTOR: sqlite3_stmt 3982** 3983** To execute an SQL statement, it must first be compiled into a byte-code 3984** program using one of these routines. Or, in other words, these routines 3985** are constructors for the [prepared statement] object. 3986** 3987** The preferred routine to use is [sqlite3_prepare_v2()]. The 3988** [sqlite3_prepare()] interface is legacy and should be avoided. 3989** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3990** for special purposes. 3991** 3992** The use of the UTF-8 interfaces is preferred, as SQLite currently 3993** does all parsing using UTF-8. The UTF-16 interfaces are provided 3994** as a convenience. The UTF-16 interfaces work by converting the 3995** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3996** 3997** The first argument, "db", is a [database connection] obtained from a 3998** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3999** [sqlite3_open16()]. The database connection must not have been closed. 4000** 4001** The second argument, "zSql", is the statement to be compiled, encoded 4002** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 4003** and sqlite3_prepare_v3() 4004** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 4005** and sqlite3_prepare16_v3() use UTF-16. 4006** 4007** ^If the nByte argument is negative, then zSql is read up to the 4008** first zero terminator. ^If nByte is positive, then it is the 4009** number of bytes read from zSql. ^If nByte is zero, then no prepared 4010** statement is generated. 4011** If the caller knows that the supplied string is nul-terminated, then 4012** there is a small performance advantage to passing an nByte parameter that 4013** is the number of bytes in the input string <i>including</i> 4014** the nul-terminator. 4015** 4016** ^If pzTail is not NULL then *pzTail is made to point to the first byte 4017** past the end of the first SQL statement in zSql. These routines only 4018** compile the first statement in zSql, so *pzTail is left pointing to 4019** what remains uncompiled. 4020** 4021** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 4022** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 4023** to NULL. ^If the input text contains no SQL (if the input is an empty 4024** string or a comment) then *ppStmt is set to NULL. 4025** The calling procedure is responsible for deleting the compiled 4026** SQL statement using [sqlite3_finalize()] after it has finished with it. 4027** ppStmt may not be NULL. 4028** 4029** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 4030** otherwise an [error code] is returned. 4031** 4032** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 4033** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 4034** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 4035** are retained for backwards compatibility, but their use is discouraged. 4036** ^In the "vX" interfaces, the prepared statement 4037** that is returned (the [sqlite3_stmt] object) contains a copy of the 4038** original SQL text. This causes the [sqlite3_step()] interface to 4039** behave differently in three ways: 4040** 4041** <ol> 4042** <li> 4043** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 4044** always used to do, [sqlite3_step()] will automatically recompile the SQL 4045** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 4046** retries will occur before sqlite3_step() gives up and returns an error. 4047** </li> 4048** 4049** <li> 4050** ^When an error occurs, [sqlite3_step()] will return one of the detailed 4051** [error codes] or [extended error codes]. ^The legacy behavior was that 4052** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 4053** and the application would have to make a second call to [sqlite3_reset()] 4054** in order to find the underlying cause of the problem. With the "v2" prepare 4055** interfaces, the underlying reason for the error is returned immediately. 4056** </li> 4057** 4058** <li> 4059** ^If the specific value bound to a [parameter | host parameter] in the 4060** WHERE clause might influence the choice of query plan for a statement, 4061** then the statement will be automatically recompiled, as if there had been 4062** a schema change, on the first [sqlite3_step()] call following any change 4063** to the [sqlite3_bind_text | bindings] of that [parameter]. 4064** ^The specific value of a WHERE-clause [parameter] might influence the 4065** choice of query plan if the parameter is the left-hand side of a [LIKE] 4066** or [GLOB] operator or if the parameter is compared to an indexed column 4067** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled. 4068** </li> 4069** </ol> 4070** 4071** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 4072** the extra prepFlags parameter, which is a bit array consisting of zero or 4073** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 4074** sqlite3_prepare_v2() interface works exactly the same as 4075** sqlite3_prepare_v3() with a zero prepFlags parameter. 4076*/ 4077int sqlite3_prepare( 4078 sqlite3 *db, /* Database handle */ 4079 const char *zSql, /* SQL statement, UTF-8 encoded */ 4080 int nByte, /* Maximum length of zSql in bytes. */ 4081 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4082 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4083); 4084int sqlite3_prepare_v2( 4085 sqlite3 *db, /* Database handle */ 4086 const char *zSql, /* SQL statement, UTF-8 encoded */ 4087 int nByte, /* Maximum length of zSql in bytes. */ 4088 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4089 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4090); 4091int sqlite3_prepare_v3( 4092 sqlite3 *db, /* Database handle */ 4093 const char *zSql, /* SQL statement, UTF-8 encoded */ 4094 int nByte, /* Maximum length of zSql in bytes. */ 4095 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4096 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4097 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4098); 4099int sqlite3_prepare16( 4100 sqlite3 *db, /* Database handle */ 4101 const void *zSql, /* SQL statement, UTF-16 encoded */ 4102 int nByte, /* Maximum length of zSql in bytes. */ 4103 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4104 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4105); 4106int sqlite3_prepare16_v2( 4107 sqlite3 *db, /* Database handle */ 4108 const void *zSql, /* SQL statement, UTF-16 encoded */ 4109 int nByte, /* Maximum length of zSql in bytes. */ 4110 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4111 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4112); 4113int sqlite3_prepare16_v3( 4114 sqlite3 *db, /* Database handle */ 4115 const void *zSql, /* SQL statement, UTF-16 encoded */ 4116 int nByte, /* Maximum length of zSql in bytes. */ 4117 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4118 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4119 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4120); 4121 4122/* 4123** CAPI3REF: Retrieving Statement SQL 4124** METHOD: sqlite3_stmt 4125** 4126** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 4127** SQL text used to create [prepared statement] P if P was 4128** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 4129** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4130** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 4131** string containing the SQL text of prepared statement P with 4132** [bound parameters] expanded. 4133** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8 4134** string containing the normalized SQL text of prepared statement P. The 4135** semantics used to normalize a SQL statement are unspecified and subject 4136** to change. At a minimum, literal values will be replaced with suitable 4137** placeholders. 4138** 4139** ^(For example, if a prepared statement is created using the SQL 4140** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 4141** and parameter :xyz is unbound, then sqlite3_sql() will return 4142** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 4143** will return "SELECT 2345,NULL".)^ 4144** 4145** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 4146** is available to hold the result, or if the result would exceed the 4147** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 4148** 4149** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 4150** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 4151** option causes sqlite3_expanded_sql() to always return NULL. 4152** 4153** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P) 4154** are managed by SQLite and are automatically freed when the prepared 4155** statement is finalized. 4156** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 4157** is obtained from [sqlite3_malloc()] and must be free by the application 4158** by passing it to [sqlite3_free()]. 4159*/ 4160const char *sqlite3_sql(sqlite3_stmt *pStmt); 4161char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 4162const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt); 4163 4164/* 4165** CAPI3REF: Determine If An SQL Statement Writes The Database 4166** METHOD: sqlite3_stmt 4167** 4168** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 4169** and only if the [prepared statement] X makes no direct changes to 4170** the content of the database file. 4171** 4172** Note that [application-defined SQL functions] or 4173** [virtual tables] might change the database indirectly as a side effect. 4174** ^(For example, if an application defines a function "eval()" that 4175** calls [sqlite3_exec()], then the following SQL statement would 4176** change the database file through side-effects: 4177** 4178** <blockquote><pre> 4179** SELECT eval('DELETE FROM t1') FROM t2; 4180** </pre></blockquote> 4181** 4182** But because the [SELECT] statement does not change the database file 4183** directly, sqlite3_stmt_readonly() would still return true.)^ 4184** 4185** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 4186** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 4187** since the statements themselves do not actually modify the database but 4188** rather they control the timing of when other statements modify the 4189** database. ^The [ATTACH] and [DETACH] statements also cause 4190** sqlite3_stmt_readonly() to return true since, while those statements 4191** change the configuration of a database connection, they do not make 4192** changes to the content of the database files on disk. 4193** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 4194** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 4195** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 4196** sqlite3_stmt_readonly() returns false for those commands. 4197*/ 4198int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 4199 4200/* 4201** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement 4202** METHOD: sqlite3_stmt 4203** 4204** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the 4205** prepared statement S is an EXPLAIN statement, or 2 if the 4206** statement S is an EXPLAIN QUERY PLAN. 4207** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is 4208** an ordinary statement or a NULL pointer. 4209*/ 4210int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt); 4211 4212/* 4213** CAPI3REF: Determine If A Prepared Statement Has Been Reset 4214** METHOD: sqlite3_stmt 4215** 4216** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 4217** [prepared statement] S has been stepped at least once using 4218** [sqlite3_step(S)] but has neither run to completion (returned 4219** [SQLITE_DONE] from [sqlite3_step(S)]) nor 4220** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 4221** interface returns false if S is a NULL pointer. If S is not a 4222** NULL pointer and is not a pointer to a valid [prepared statement] 4223** object, then the behavior is undefined and probably undesirable. 4224** 4225** This interface can be used in combination [sqlite3_next_stmt()] 4226** to locate all prepared statements associated with a database 4227** connection that are in need of being reset. This can be used, 4228** for example, in diagnostic routines to search for prepared 4229** statements that are holding a transaction open. 4230*/ 4231int sqlite3_stmt_busy(sqlite3_stmt*); 4232 4233/* 4234** CAPI3REF: Dynamically Typed Value Object 4235** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 4236** 4237** SQLite uses the sqlite3_value object to represent all values 4238** that can be stored in a database table. SQLite uses dynamic typing 4239** for the values it stores. ^Values stored in sqlite3_value objects 4240** can be integers, floating point values, strings, BLOBs, or NULL. 4241** 4242** An sqlite3_value object may be either "protected" or "unprotected". 4243** Some interfaces require a protected sqlite3_value. Other interfaces 4244** will accept either a protected or an unprotected sqlite3_value. 4245** Every interface that accepts sqlite3_value arguments specifies 4246** whether or not it requires a protected sqlite3_value. The 4247** [sqlite3_value_dup()] interface can be used to construct a new 4248** protected sqlite3_value from an unprotected sqlite3_value. 4249** 4250** The terms "protected" and "unprotected" refer to whether or not 4251** a mutex is held. An internal mutex is held for a protected 4252** sqlite3_value object but no mutex is held for an unprotected 4253** sqlite3_value object. If SQLite is compiled to be single-threaded 4254** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 4255** or if SQLite is run in one of reduced mutex modes 4256** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 4257** then there is no distinction between protected and unprotected 4258** sqlite3_value objects and they can be used interchangeably. However, 4259** for maximum code portability it is recommended that applications 4260** still make the distinction between protected and unprotected 4261** sqlite3_value objects even when not strictly required. 4262** 4263** ^The sqlite3_value objects that are passed as parameters into the 4264** implementation of [application-defined SQL functions] are protected. 4265** ^The sqlite3_value object returned by 4266** [sqlite3_column_value()] is unprotected. 4267** Unprotected sqlite3_value objects may only be used as arguments 4268** to [sqlite3_result_value()], [sqlite3_bind_value()], and 4269** [sqlite3_value_dup()]. 4270** The [sqlite3_value_blob | sqlite3_value_type()] family of 4271** interfaces require protected sqlite3_value objects. 4272*/ 4273typedef struct sqlite3_value sqlite3_value; 4274 4275/* 4276** CAPI3REF: SQL Function Context Object 4277** 4278** The context in which an SQL function executes is stored in an 4279** sqlite3_context object. ^A pointer to an sqlite3_context object 4280** is always first parameter to [application-defined SQL functions]. 4281** The application-defined SQL function implementation will pass this 4282** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 4283** [sqlite3_aggregate_context()], [sqlite3_user_data()], 4284** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 4285** and/or [sqlite3_set_auxdata()]. 4286*/ 4287typedef struct sqlite3_context sqlite3_context; 4288 4289/* 4290** CAPI3REF: Binding Values To Prepared Statements 4291** KEYWORDS: {host parameter} {host parameters} {host parameter name} 4292** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 4293** METHOD: sqlite3_stmt 4294** 4295** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 4296** literals may be replaced by a [parameter] that matches one of following 4297** templates: 4298** 4299** <ul> 4300** <li> ? 4301** <li> ?NNN 4302** <li> :VVV 4303** <li> @VVV 4304** <li> $VVV 4305** </ul> 4306** 4307** In the templates above, NNN represents an integer literal, 4308** and VVV represents an alphanumeric identifier.)^ ^The values of these 4309** parameters (also called "host parameter names" or "SQL parameters") 4310** can be set using the sqlite3_bind_*() routines defined here. 4311** 4312** ^The first argument to the sqlite3_bind_*() routines is always 4313** a pointer to the [sqlite3_stmt] object returned from 4314** [sqlite3_prepare_v2()] or its variants. 4315** 4316** ^The second argument is the index of the SQL parameter to be set. 4317** ^The leftmost SQL parameter has an index of 1. ^When the same named 4318** SQL parameter is used more than once, second and subsequent 4319** occurrences have the same index as the first occurrence. 4320** ^The index for named parameters can be looked up using the 4321** [sqlite3_bind_parameter_index()] API if desired. ^The index 4322** for "?NNN" parameters is the value of NNN. 4323** ^The NNN value must be between 1 and the [sqlite3_limit()] 4324** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766). 4325** 4326** ^The third argument is the value to bind to the parameter. 4327** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4328** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 4329** is ignored and the end result is the same as sqlite3_bind_null(). 4330** ^If the third parameter to sqlite3_bind_text() is not NULL, then 4331** it should be a pointer to well-formed UTF8 text. 4332** ^If the third parameter to sqlite3_bind_text16() is not NULL, then 4333** it should be a pointer to well-formed UTF16 text. 4334** ^If the third parameter to sqlite3_bind_text64() is not NULL, then 4335** it should be a pointer to a well-formed unicode string that is 4336** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16 4337** otherwise. 4338** 4339** [[byte-order determination rules]] ^The byte-order of 4340** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF) 4341** found in first character, which is removed, or in the absence of a BOM 4342** the byte order is the native byte order of the host 4343** machine for sqlite3_bind_text16() or the byte order specified in 4344** the 6th parameter for sqlite3_bind_text64().)^ 4345** ^If UTF16 input text contains invalid unicode 4346** characters, then SQLite might change those invalid characters 4347** into the unicode replacement character: U+FFFD. 4348** 4349** ^(In those routines that have a fourth argument, its value is the 4350** number of bytes in the parameter. To be clear: the value is the 4351** number of <u>bytes</u> in the value, not the number of characters.)^ 4352** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4353** is negative, then the length of the string is 4354** the number of bytes up to the first zero terminator. 4355** If the fourth parameter to sqlite3_bind_blob() is negative, then 4356** the behavior is undefined. 4357** If a non-negative fourth parameter is provided to sqlite3_bind_text() 4358** or sqlite3_bind_text16() or sqlite3_bind_text64() then 4359** that parameter must be the byte offset 4360** where the NUL terminator would occur assuming the string were NUL 4361** terminated. If any NUL characters occurs at byte offsets less than 4362** the value of the fourth parameter then the resulting string value will 4363** contain embedded NULs. The result of expressions involving strings 4364** with embedded NULs is undefined. 4365** 4366** ^The fifth argument to the BLOB and string binding interfaces 4367** is a destructor used to dispose of the BLOB or 4368** string after SQLite has finished with it. ^The destructor is called 4369** to dispose of the BLOB or string even if the call to the bind API fails, 4370** except the destructor is not called if the third parameter is a NULL 4371** pointer or the fourth parameter is negative. 4372** ^If the fifth argument is 4373** the special value [SQLITE_STATIC], then SQLite assumes that the 4374** information is in static, unmanaged space and does not need to be freed. 4375** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 4376** SQLite makes its own private copy of the data immediately, before 4377** the sqlite3_bind_*() routine returns. 4378** 4379** ^The sixth argument to sqlite3_bind_text64() must be one of 4380** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 4381** to specify the encoding of the text in the third parameter. If 4382** the sixth argument to sqlite3_bind_text64() is not one of the 4383** allowed values shown above, or if the text encoding is different 4384** from the encoding specified by the sixth parameter, then the behavior 4385** is undefined. 4386** 4387** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 4388** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 4389** (just an integer to hold its size) while it is being processed. 4390** Zeroblobs are intended to serve as placeholders for BLOBs whose 4391** content is later written using 4392** [sqlite3_blob_open | incremental BLOB I/O] routines. 4393** ^A negative value for the zeroblob results in a zero-length BLOB. 4394** 4395** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 4396** [prepared statement] S to have an SQL value of NULL, but to also be 4397** associated with the pointer P of type T. ^D is either a NULL pointer or 4398** a pointer to a destructor function for P. ^SQLite will invoke the 4399** destructor D with a single argument of P when it is finished using 4400** P. The T parameter should be a static string, preferably a string 4401** literal. The sqlite3_bind_pointer() routine is part of the 4402** [pointer passing interface] added for SQLite 3.20.0. 4403** 4404** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 4405** for the [prepared statement] or with a prepared statement for which 4406** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 4407** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 4408** routine is passed a [prepared statement] that has been finalized, the 4409** result is undefined and probably harmful. 4410** 4411** ^Bindings are not cleared by the [sqlite3_reset()] routine. 4412** ^Unbound parameters are interpreted as NULL. 4413** 4414** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 4415** [error code] if anything goes wrong. 4416** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 4417** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 4418** [SQLITE_MAX_LENGTH]. 4419** ^[SQLITE_RANGE] is returned if the parameter 4420** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 4421** 4422** See also: [sqlite3_bind_parameter_count()], 4423** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 4424*/ 4425int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 4426int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 4427 void(*)(void*)); 4428int sqlite3_bind_double(sqlite3_stmt*, int, double); 4429int sqlite3_bind_int(sqlite3_stmt*, int, int); 4430int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 4431int sqlite3_bind_null(sqlite3_stmt*, int); 4432int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 4433int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 4434int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 4435 void(*)(void*), unsigned char encoding); 4436int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 4437int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 4438int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 4439int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 4440 4441/* 4442** CAPI3REF: Number Of SQL Parameters 4443** METHOD: sqlite3_stmt 4444** 4445** ^This routine can be used to find the number of [SQL parameters] 4446** in a [prepared statement]. SQL parameters are tokens of the 4447** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4448** placeholders for values that are [sqlite3_bind_blob | bound] 4449** to the parameters at a later time. 4450** 4451** ^(This routine actually returns the index of the largest (rightmost) 4452** parameter. For all forms except ?NNN, this will correspond to the 4453** number of unique parameters. If parameters of the ?NNN form are used, 4454** there may be gaps in the list.)^ 4455** 4456** See also: [sqlite3_bind_blob|sqlite3_bind()], 4457** [sqlite3_bind_parameter_name()], and 4458** [sqlite3_bind_parameter_index()]. 4459*/ 4460int sqlite3_bind_parameter_count(sqlite3_stmt*); 4461 4462/* 4463** CAPI3REF: Name Of A Host Parameter 4464** METHOD: sqlite3_stmt 4465** 4466** ^The sqlite3_bind_parameter_name(P,N) interface returns 4467** the name of the N-th [SQL parameter] in the [prepared statement] P. 4468** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4469** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4470** respectively. 4471** In other words, the initial ":" or "$" or "@" or "?" 4472** is included as part of the name.)^ 4473** ^Parameters of the form "?" without a following integer have no name 4474** and are referred to as "nameless" or "anonymous parameters". 4475** 4476** ^The first host parameter has an index of 1, not 0. 4477** 4478** ^If the value N is out of range or if the N-th parameter is 4479** nameless, then NULL is returned. ^The returned string is 4480** always in UTF-8 encoding even if the named parameter was 4481** originally specified as UTF-16 in [sqlite3_prepare16()], 4482** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4483** 4484** See also: [sqlite3_bind_blob|sqlite3_bind()], 4485** [sqlite3_bind_parameter_count()], and 4486** [sqlite3_bind_parameter_index()]. 4487*/ 4488const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4489 4490/* 4491** CAPI3REF: Index Of A Parameter With A Given Name 4492** METHOD: sqlite3_stmt 4493** 4494** ^Return the index of an SQL parameter given its name. ^The 4495** index value returned is suitable for use as the second 4496** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4497** is returned if no matching parameter is found. ^The parameter 4498** name must be given in UTF-8 even if the original statement 4499** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4500** [sqlite3_prepare16_v3()]. 4501** 4502** See also: [sqlite3_bind_blob|sqlite3_bind()], 4503** [sqlite3_bind_parameter_count()], and 4504** [sqlite3_bind_parameter_name()]. 4505*/ 4506int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4507 4508/* 4509** CAPI3REF: Reset All Bindings On A Prepared Statement 4510** METHOD: sqlite3_stmt 4511** 4512** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4513** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4514** ^Use this routine to reset all host parameters to NULL. 4515*/ 4516int sqlite3_clear_bindings(sqlite3_stmt*); 4517 4518/* 4519** CAPI3REF: Number Of Columns In A Result Set 4520** METHOD: sqlite3_stmt 4521** 4522** ^Return the number of columns in the result set returned by the 4523** [prepared statement]. ^If this routine returns 0, that means the 4524** [prepared statement] returns no data (for example an [UPDATE]). 4525** ^However, just because this routine returns a positive number does not 4526** mean that one or more rows of data will be returned. ^A SELECT statement 4527** will always have a positive sqlite3_column_count() but depending on the 4528** WHERE clause constraints and the table content, it might return no rows. 4529** 4530** See also: [sqlite3_data_count()] 4531*/ 4532int sqlite3_column_count(sqlite3_stmt *pStmt); 4533 4534/* 4535** CAPI3REF: Column Names In A Result Set 4536** METHOD: sqlite3_stmt 4537** 4538** ^These routines return the name assigned to a particular column 4539** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4540** interface returns a pointer to a zero-terminated UTF-8 string 4541** and sqlite3_column_name16() returns a pointer to a zero-terminated 4542** UTF-16 string. ^The first parameter is the [prepared statement] 4543** that implements the [SELECT] statement. ^The second parameter is the 4544** column number. ^The leftmost column is number 0. 4545** 4546** ^The returned string pointer is valid until either the [prepared statement] 4547** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4548** reprepared by the first call to [sqlite3_step()] for a particular run 4549** or until the next call to 4550** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4551** 4552** ^If sqlite3_malloc() fails during the processing of either routine 4553** (for example during a conversion from UTF-8 to UTF-16) then a 4554** NULL pointer is returned. 4555** 4556** ^The name of a result column is the value of the "AS" clause for 4557** that column, if there is an AS clause. If there is no AS clause 4558** then the name of the column is unspecified and may change from 4559** one release of SQLite to the next. 4560*/ 4561const char *sqlite3_column_name(sqlite3_stmt*, int N); 4562const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4563 4564/* 4565** CAPI3REF: Source Of Data In A Query Result 4566** METHOD: sqlite3_stmt 4567** 4568** ^These routines provide a means to determine the database, table, and 4569** table column that is the origin of a particular result column in 4570** [SELECT] statement. 4571** ^The name of the database or table or column can be returned as 4572** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4573** the database name, the _table_ routines return the table name, and 4574** the origin_ routines return the column name. 4575** ^The returned string is valid until the [prepared statement] is destroyed 4576** using [sqlite3_finalize()] or until the statement is automatically 4577** reprepared by the first call to [sqlite3_step()] for a particular run 4578** or until the same information is requested 4579** again in a different encoding. 4580** 4581** ^The names returned are the original un-aliased names of the 4582** database, table, and column. 4583** 4584** ^The first argument to these interfaces is a [prepared statement]. 4585** ^These functions return information about the Nth result column returned by 4586** the statement, where N is the second function argument. 4587** ^The left-most column is column 0 for these routines. 4588** 4589** ^If the Nth column returned by the statement is an expression or 4590** subquery and is not a column value, then all of these functions return 4591** NULL. ^These routines might also return NULL if a memory allocation error 4592** occurs. ^Otherwise, they return the name of the attached database, table, 4593** or column that query result column was extracted from. 4594** 4595** ^As with all other SQLite APIs, those whose names end with "16" return 4596** UTF-16 encoded strings and the other functions return UTF-8. 4597** 4598** ^These APIs are only available if the library was compiled with the 4599** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4600** 4601** If two or more threads call one or more 4602** [sqlite3_column_database_name | column metadata interfaces] 4603** for the same [prepared statement] and result column 4604** at the same time then the results are undefined. 4605*/ 4606const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4607const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4608const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4609const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4610const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4611const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4612 4613/* 4614** CAPI3REF: Declared Datatype Of A Query Result 4615** METHOD: sqlite3_stmt 4616** 4617** ^(The first parameter is a [prepared statement]. 4618** If this statement is a [SELECT] statement and the Nth column of the 4619** returned result set of that [SELECT] is a table column (not an 4620** expression or subquery) then the declared type of the table 4621** column is returned.)^ ^If the Nth column of the result set is an 4622** expression or subquery, then a NULL pointer is returned. 4623** ^The returned string is always UTF-8 encoded. 4624** 4625** ^(For example, given the database schema: 4626** 4627** CREATE TABLE t1(c1 VARIANT); 4628** 4629** and the following statement to be compiled: 4630** 4631** SELECT c1 + 1, c1 FROM t1; 4632** 4633** this routine would return the string "VARIANT" for the second result 4634** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4635** 4636** ^SQLite uses dynamic run-time typing. ^So just because a column 4637** is declared to contain a particular type does not mean that the 4638** data stored in that column is of the declared type. SQLite is 4639** strongly typed, but the typing is dynamic not static. ^Type 4640** is associated with individual values, not with the containers 4641** used to hold those values. 4642*/ 4643const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4644const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4645 4646/* 4647** CAPI3REF: Evaluate An SQL Statement 4648** METHOD: sqlite3_stmt 4649** 4650** After a [prepared statement] has been prepared using any of 4651** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4652** or [sqlite3_prepare16_v3()] or one of the legacy 4653** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4654** must be called one or more times to evaluate the statement. 4655** 4656** The details of the behavior of the sqlite3_step() interface depend 4657** on whether the statement was prepared using the newer "vX" interfaces 4658** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4659** [sqlite3_prepare16_v2()] or the older legacy 4660** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4661** new "vX" interface is recommended for new applications but the legacy 4662** interface will continue to be supported. 4663** 4664** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4665** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4666** ^With the "v2" interface, any of the other [result codes] or 4667** [extended result codes] might be returned as well. 4668** 4669** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4670** database locks it needs to do its job. ^If the statement is a [COMMIT] 4671** or occurs outside of an explicit transaction, then you can retry the 4672** statement. If the statement is not a [COMMIT] and occurs within an 4673** explicit transaction then you should rollback the transaction before 4674** continuing. 4675** 4676** ^[SQLITE_DONE] means that the statement has finished executing 4677** successfully. sqlite3_step() should not be called again on this virtual 4678** machine without first calling [sqlite3_reset()] to reset the virtual 4679** machine back to its initial state. 4680** 4681** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4682** is returned each time a new row of data is ready for processing by the 4683** caller. The values may be accessed using the [column access functions]. 4684** sqlite3_step() is called again to retrieve the next row of data. 4685** 4686** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4687** violation) has occurred. sqlite3_step() should not be called again on 4688** the VM. More information may be found by calling [sqlite3_errmsg()]. 4689** ^With the legacy interface, a more specific error code (for example, 4690** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4691** can be obtained by calling [sqlite3_reset()] on the 4692** [prepared statement]. ^In the "v2" interface, 4693** the more specific error code is returned directly by sqlite3_step(). 4694** 4695** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4696** Perhaps it was called on a [prepared statement] that has 4697** already been [sqlite3_finalize | finalized] or on one that had 4698** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4699** be the case that the same database connection is being used by two or 4700** more threads at the same moment in time. 4701** 4702** For all versions of SQLite up to and including 3.6.23.1, a call to 4703** [sqlite3_reset()] was required after sqlite3_step() returned anything 4704** other than [SQLITE_ROW] before any subsequent invocation of 4705** sqlite3_step(). Failure to reset the prepared statement using 4706** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4707** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4708** sqlite3_step() began 4709** calling [sqlite3_reset()] automatically in this circumstance rather 4710** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4711** break because any application that ever receives an SQLITE_MISUSE error 4712** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4713** can be used to restore the legacy behavior. 4714** 4715** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4716** API always returns a generic error code, [SQLITE_ERROR], following any 4717** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4718** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4719** specific [error codes] that better describes the error. 4720** We admit that this is a goofy design. The problem has been fixed 4721** with the "v2" interface. If you prepare all of your SQL statements 4722** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4723** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4724** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4725** then the more specific [error codes] are returned directly 4726** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4727*/ 4728int sqlite3_step(sqlite3_stmt*); 4729 4730/* 4731** CAPI3REF: Number of columns in a result set 4732** METHOD: sqlite3_stmt 4733** 4734** ^The sqlite3_data_count(P) interface returns the number of columns in the 4735** current row of the result set of [prepared statement] P. 4736** ^If prepared statement P does not have results ready to return 4737** (via calls to the [sqlite3_column_int | sqlite3_column()] family of 4738** interfaces) then sqlite3_data_count(P) returns 0. 4739** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4740** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4741** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4742** will return non-zero if previous call to [sqlite3_step](P) returned 4743** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4744** where it always returns zero since each step of that multi-step 4745** pragma returns 0 columns of data. 4746** 4747** See also: [sqlite3_column_count()] 4748*/ 4749int sqlite3_data_count(sqlite3_stmt *pStmt); 4750 4751/* 4752** CAPI3REF: Fundamental Datatypes 4753** KEYWORDS: SQLITE_TEXT 4754** 4755** ^(Every value in SQLite has one of five fundamental datatypes: 4756** 4757** <ul> 4758** <li> 64-bit signed integer 4759** <li> 64-bit IEEE floating point number 4760** <li> string 4761** <li> BLOB 4762** <li> NULL 4763** </ul>)^ 4764** 4765** These constants are codes for each of those types. 4766** 4767** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4768** for a completely different meaning. Software that links against both 4769** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4770** SQLITE_TEXT. 4771*/ 4772#define SQLITE_INTEGER 1 4773#define SQLITE_FLOAT 2 4774#define SQLITE_BLOB 4 4775#define SQLITE_NULL 5 4776#ifdef SQLITE_TEXT 4777# undef SQLITE_TEXT 4778#else 4779# define SQLITE_TEXT 3 4780#endif 4781#define SQLITE3_TEXT 3 4782 4783/* 4784** CAPI3REF: Result Values From A Query 4785** KEYWORDS: {column access functions} 4786** METHOD: sqlite3_stmt 4787** 4788** <b>Summary:</b> 4789** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4790** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4791** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4792** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4793** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4794** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4795** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4796** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4797** [sqlite3_value|unprotected sqlite3_value] object. 4798** <tr><td> <td> <td> 4799** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4800** or a UTF-8 TEXT result in bytes 4801** <tr><td><b>sqlite3_column_bytes16 </b> 4802** <td>→ <td>Size of UTF-16 4803** TEXT in bytes 4804** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4805** datatype of the result 4806** </table></blockquote> 4807** 4808** <b>Details:</b> 4809** 4810** ^These routines return information about a single column of the current 4811** result row of a query. ^In every case the first argument is a pointer 4812** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4813** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4814** and the second argument is the index of the column for which information 4815** should be returned. ^The leftmost column of the result set has the index 0. 4816** ^The number of columns in the result can be determined using 4817** [sqlite3_column_count()]. 4818** 4819** If the SQL statement does not currently point to a valid row, or if the 4820** column index is out of range, the result is undefined. 4821** These routines may only be called when the most recent call to 4822** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4823** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4824** If any of these routines are called after [sqlite3_reset()] or 4825** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4826** something other than [SQLITE_ROW], the results are undefined. 4827** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4828** are called from a different thread while any of these routines 4829** are pending, then the results are undefined. 4830** 4831** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4832** each return the value of a result column in a specific data format. If 4833** the result column is not initially in the requested format (for example, 4834** if the query returns an integer but the sqlite3_column_text() interface 4835** is used to extract the value) then an automatic type conversion is performed. 4836** 4837** ^The sqlite3_column_type() routine returns the 4838** [SQLITE_INTEGER | datatype code] for the initial data type 4839** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4840** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4841** The return value of sqlite3_column_type() can be used to decide which 4842** of the first six interface should be used to extract the column value. 4843** The value returned by sqlite3_column_type() is only meaningful if no 4844** automatic type conversions have occurred for the value in question. 4845** After a type conversion, the result of calling sqlite3_column_type() 4846** is undefined, though harmless. Future 4847** versions of SQLite may change the behavior of sqlite3_column_type() 4848** following a type conversion. 4849** 4850** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4851** or sqlite3_column_bytes16() interfaces can be used to determine the size 4852** of that BLOB or string. 4853** 4854** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4855** routine returns the number of bytes in that BLOB or string. 4856** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4857** the string to UTF-8 and then returns the number of bytes. 4858** ^If the result is a numeric value then sqlite3_column_bytes() uses 4859** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4860** the number of bytes in that string. 4861** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4862** 4863** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4864** routine returns the number of bytes in that BLOB or string. 4865** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4866** the string to UTF-16 and then returns the number of bytes. 4867** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4868** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4869** the number of bytes in that string. 4870** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4871** 4872** ^The values returned by [sqlite3_column_bytes()] and 4873** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4874** of the string. ^For clarity: the values returned by 4875** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4876** bytes in the string, not the number of characters. 4877** 4878** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4879** even empty strings, are always zero-terminated. ^The return 4880** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4881** 4882** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4883** [unprotected sqlite3_value] object. In a multithreaded environment, 4884** an unprotected sqlite3_value object may only be used safely with 4885** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4886** If the [unprotected sqlite3_value] object returned by 4887** [sqlite3_column_value()] is used in any other way, including calls 4888** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4889** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4890** Hence, the sqlite3_column_value() interface 4891** is normally only useful within the implementation of 4892** [application-defined SQL functions] or [virtual tables], not within 4893** top-level application code. 4894** 4895** The these routines may attempt to convert the datatype of the result. 4896** ^For example, if the internal representation is FLOAT and a text result 4897** is requested, [sqlite3_snprintf()] is used internally to perform the 4898** conversion automatically. ^(The following table details the conversions 4899** that are applied: 4900** 4901** <blockquote> 4902** <table border="1"> 4903** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4904** 4905** <tr><td> NULL <td> INTEGER <td> Result is 0 4906** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4907** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4908** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4909** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4910** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4911** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4912** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4913** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4914** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4915** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4916** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4917** <tr><td> TEXT <td> BLOB <td> No change 4918** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4919** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4920** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4921** </table> 4922** </blockquote>)^ 4923** 4924** Note that when type conversions occur, pointers returned by prior 4925** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4926** sqlite3_column_text16() may be invalidated. 4927** Type conversions and pointer invalidations might occur 4928** in the following cases: 4929** 4930** <ul> 4931** <li> The initial content is a BLOB and sqlite3_column_text() or 4932** sqlite3_column_text16() is called. A zero-terminator might 4933** need to be added to the string.</li> 4934** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4935** sqlite3_column_text16() is called. The content must be converted 4936** to UTF-16.</li> 4937** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4938** sqlite3_column_text() is called. The content must be converted 4939** to UTF-8.</li> 4940** </ul> 4941** 4942** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4943** not invalidate a prior pointer, though of course the content of the buffer 4944** that the prior pointer references will have been modified. Other kinds 4945** of conversion are done in place when it is possible, but sometimes they 4946** are not possible and in those cases prior pointers are invalidated. 4947** 4948** The safest policy is to invoke these routines 4949** in one of the following ways: 4950** 4951** <ul> 4952** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4953** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4954** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4955** </ul> 4956** 4957** In other words, you should call sqlite3_column_text(), 4958** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4959** into the desired format, then invoke sqlite3_column_bytes() or 4960** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4961** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4962** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4963** with calls to sqlite3_column_bytes(). 4964** 4965** ^The pointers returned are valid until a type conversion occurs as 4966** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4967** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4968** and BLOBs is freed automatically. Do not pass the pointers returned 4969** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4970** [sqlite3_free()]. 4971** 4972** As long as the input parameters are correct, these routines will only 4973** fail if an out-of-memory error occurs during a format conversion. 4974** Only the following subset of interfaces are subject to out-of-memory 4975** errors: 4976** 4977** <ul> 4978** <li> sqlite3_column_blob() 4979** <li> sqlite3_column_text() 4980** <li> sqlite3_column_text16() 4981** <li> sqlite3_column_bytes() 4982** <li> sqlite3_column_bytes16() 4983** </ul> 4984** 4985** If an out-of-memory error occurs, then the return value from these 4986** routines is the same as if the column had contained an SQL NULL value. 4987** Valid SQL NULL returns can be distinguished from out-of-memory errors 4988** by invoking the [sqlite3_errcode()] immediately after the suspect 4989** return value is obtained and before any 4990** other SQLite interface is called on the same [database connection]. 4991*/ 4992const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4993double sqlite3_column_double(sqlite3_stmt*, int iCol); 4994int sqlite3_column_int(sqlite3_stmt*, int iCol); 4995sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4996const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4997const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4998sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4999int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 5000int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 5001int sqlite3_column_type(sqlite3_stmt*, int iCol); 5002 5003/* 5004** CAPI3REF: Destroy A Prepared Statement Object 5005** DESTRUCTOR: sqlite3_stmt 5006** 5007** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 5008** ^If the most recent evaluation of the statement encountered no errors 5009** or if the statement is never been evaluated, then sqlite3_finalize() returns 5010** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 5011** sqlite3_finalize(S) returns the appropriate [error code] or 5012** [extended error code]. 5013** 5014** ^The sqlite3_finalize(S) routine can be called at any point during 5015** the life cycle of [prepared statement] S: 5016** before statement S is ever evaluated, after 5017** one or more calls to [sqlite3_reset()], or after any call 5018** to [sqlite3_step()] regardless of whether or not the statement has 5019** completed execution. 5020** 5021** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 5022** 5023** The application must finalize every [prepared statement] in order to avoid 5024** resource leaks. It is a grievous error for the application to try to use 5025** a prepared statement after it has been finalized. Any use of a prepared 5026** statement after it has been finalized can result in undefined and 5027** undesirable behavior such as segfaults and heap corruption. 5028*/ 5029int sqlite3_finalize(sqlite3_stmt *pStmt); 5030 5031/* 5032** CAPI3REF: Reset A Prepared Statement Object 5033** METHOD: sqlite3_stmt 5034** 5035** The sqlite3_reset() function is called to reset a [prepared statement] 5036** object back to its initial state, ready to be re-executed. 5037** ^Any SQL statement variables that had values bound to them using 5038** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 5039** Use [sqlite3_clear_bindings()] to reset the bindings. 5040** 5041** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 5042** back to the beginning of its program. 5043** 5044** ^If the most recent call to [sqlite3_step(S)] for the 5045** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 5046** or if [sqlite3_step(S)] has never before been called on S, 5047** then [sqlite3_reset(S)] returns [SQLITE_OK]. 5048** 5049** ^If the most recent call to [sqlite3_step(S)] for the 5050** [prepared statement] S indicated an error, then 5051** [sqlite3_reset(S)] returns an appropriate [error code]. 5052** 5053** ^The [sqlite3_reset(S)] interface does not change the values 5054** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 5055*/ 5056int sqlite3_reset(sqlite3_stmt *pStmt); 5057 5058/* 5059** CAPI3REF: Create Or Redefine SQL Functions 5060** KEYWORDS: {function creation routines} 5061** METHOD: sqlite3 5062** 5063** ^These functions (collectively known as "function creation routines") 5064** are used to add SQL functions or aggregates or to redefine the behavior 5065** of existing SQL functions or aggregates. The only differences between 5066** the three "sqlite3_create_function*" routines are the text encoding 5067** expected for the second parameter (the name of the function being 5068** created) and the presence or absence of a destructor callback for 5069** the application data pointer. Function sqlite3_create_window_function() 5070** is similar, but allows the user to supply the extra callback functions 5071** needed by [aggregate window functions]. 5072** 5073** ^The first parameter is the [database connection] to which the SQL 5074** function is to be added. ^If an application uses more than one database 5075** connection then application-defined SQL functions must be added 5076** to each database connection separately. 5077** 5078** ^The second parameter is the name of the SQL function to be created or 5079** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 5080** representation, exclusive of the zero-terminator. ^Note that the name 5081** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 5082** ^Any attempt to create a function with a longer name 5083** will result in [SQLITE_MISUSE] being returned. 5084** 5085** ^The third parameter (nArg) 5086** is the number of arguments that the SQL function or 5087** aggregate takes. ^If this parameter is -1, then the SQL function or 5088** aggregate may take any number of arguments between 0 and the limit 5089** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 5090** parameter is less than -1 or greater than 127 then the behavior is 5091** undefined. 5092** 5093** ^The fourth parameter, eTextRep, specifies what 5094** [SQLITE_UTF8 | text encoding] this SQL function prefers for 5095** its parameters. The application should set this parameter to 5096** [SQLITE_UTF16LE] if the function implementation invokes 5097** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 5098** implementation invokes [sqlite3_value_text16be()] on an input, or 5099** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 5100** otherwise. ^The same SQL function may be registered multiple times using 5101** different preferred text encodings, with different implementations for 5102** each encoding. 5103** ^When multiple implementations of the same function are available, SQLite 5104** will pick the one that involves the least amount of data conversion. 5105** 5106** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 5107** to signal that the function will always return the same result given 5108** the same inputs within a single SQL statement. Most SQL functions are 5109** deterministic. The built-in [random()] SQL function is an example of a 5110** function that is not deterministic. The SQLite query planner is able to 5111** perform additional optimizations on deterministic functions, so use 5112** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 5113** 5114** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY] 5115** flag, which if present prevents the function from being invoked from 5116** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions, 5117** index expressions, or the WHERE clause of partial indexes. 5118** 5119** <span style="background-color:#ffff90;"> 5120** For best security, the [SQLITE_DIRECTONLY] flag is recommended for 5121** all application-defined SQL functions that do not need to be 5122** used inside of triggers, view, CHECK constraints, or other elements of 5123** the database schema. This flags is especially recommended for SQL 5124** functions that have side effects or reveal internal application state. 5125** Without this flag, an attacker might be able to modify the schema of 5126** a database file to include invocations of the function with parameters 5127** chosen by the attacker, which the application will then execute when 5128** the database file is opened and read. 5129** </span> 5130** 5131** ^(The fifth parameter is an arbitrary pointer. The implementation of the 5132** function can gain access to this pointer using [sqlite3_user_data()].)^ 5133** 5134** ^The sixth, seventh and eighth parameters passed to the three 5135** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are 5136** pointers to C-language functions that implement the SQL function or 5137** aggregate. ^A scalar SQL function requires an implementation of the xFunc 5138** callback only; NULL pointers must be passed as the xStep and xFinal 5139** parameters. ^An aggregate SQL function requires an implementation of xStep 5140** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 5141** SQL function or aggregate, pass NULL pointers for all three function 5142** callbacks. 5143** 5144** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue 5145** and xInverse) passed to sqlite3_create_window_function are pointers to 5146** C-language callbacks that implement the new function. xStep and xFinal 5147** must both be non-NULL. xValue and xInverse may either both be NULL, in 5148** which case a regular aggregate function is created, or must both be 5149** non-NULL, in which case the new function may be used as either an aggregate 5150** or aggregate window function. More details regarding the implementation 5151** of aggregate window functions are 5152** [user-defined window functions|available here]. 5153** 5154** ^(If the final parameter to sqlite3_create_function_v2() or 5155** sqlite3_create_window_function() is not NULL, then it is destructor for 5156** the application data pointer. The destructor is invoked when the function 5157** is deleted, either by being overloaded or when the database connection 5158** closes.)^ ^The destructor is also invoked if the call to 5159** sqlite3_create_function_v2() fails. ^When the destructor callback is 5160** invoked, it is passed a single argument which is a copy of the application 5161** data pointer which was the fifth parameter to sqlite3_create_function_v2(). 5162** 5163** ^It is permitted to register multiple implementations of the same 5164** functions with the same name but with either differing numbers of 5165** arguments or differing preferred text encodings. ^SQLite will use 5166** the implementation that most closely matches the way in which the 5167** SQL function is used. ^A function implementation with a non-negative 5168** nArg parameter is a better match than a function implementation with 5169** a negative nArg. ^A function where the preferred text encoding 5170** matches the database encoding is a better 5171** match than a function where the encoding is different. 5172** ^A function where the encoding difference is between UTF16le and UTF16be 5173** is a closer match than a function where the encoding difference is 5174** between UTF8 and UTF16. 5175** 5176** ^Built-in functions may be overloaded by new application-defined functions. 5177** 5178** ^An application-defined function is permitted to call other 5179** SQLite interfaces. However, such calls must not 5180** close the database connection nor finalize or reset the prepared 5181** statement in which the function is running. 5182*/ 5183int sqlite3_create_function( 5184 sqlite3 *db, 5185 const char *zFunctionName, 5186 int nArg, 5187 int eTextRep, 5188 void *pApp, 5189 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5190 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5191 void (*xFinal)(sqlite3_context*) 5192); 5193int sqlite3_create_function16( 5194 sqlite3 *db, 5195 const void *zFunctionName, 5196 int nArg, 5197 int eTextRep, 5198 void *pApp, 5199 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5200 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5201 void (*xFinal)(sqlite3_context*) 5202); 5203int sqlite3_create_function_v2( 5204 sqlite3 *db, 5205 const char *zFunctionName, 5206 int nArg, 5207 int eTextRep, 5208 void *pApp, 5209 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5210 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5211 void (*xFinal)(sqlite3_context*), 5212 void(*xDestroy)(void*) 5213); 5214int sqlite3_create_window_function( 5215 sqlite3 *db, 5216 const char *zFunctionName, 5217 int nArg, 5218 int eTextRep, 5219 void *pApp, 5220 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5221 void (*xFinal)(sqlite3_context*), 5222 void (*xValue)(sqlite3_context*), 5223 void (*xInverse)(sqlite3_context*,int,sqlite3_value**), 5224 void(*xDestroy)(void*) 5225); 5226 5227/* 5228** CAPI3REF: Text Encodings 5229** 5230** These constant define integer codes that represent the various 5231** text encodings supported by SQLite. 5232*/ 5233#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 5234#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 5235#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 5236#define SQLITE_UTF16 4 /* Use native byte order */ 5237#define SQLITE_ANY 5 /* Deprecated */ 5238#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 5239 5240/* 5241** CAPI3REF: Function Flags 5242** 5243** These constants may be ORed together with the 5244** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 5245** to [sqlite3_create_function()], [sqlite3_create_function16()], or 5246** [sqlite3_create_function_v2()]. 5247** 5248** <dl> 5249** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd> 5250** The SQLITE_DETERMINISTIC flag means that the new function always gives 5251** the same output when the input parameters are the same. 5252** The [abs|abs() function] is deterministic, for example, but 5253** [randomblob|randomblob()] is not. Functions must 5254** be deterministic in order to be used in certain contexts such as 5255** with the WHERE clause of [partial indexes] or in [generated columns]. 5256** SQLite might also optimize deterministic functions by factoring them 5257** out of inner loops. 5258** </dd> 5259** 5260** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd> 5261** The SQLITE_DIRECTONLY flag means that the function may only be invoked 5262** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in 5263** schema structures such as [CHECK constraints], [DEFAULT clauses], 5264** [expression indexes], [partial indexes], or [generated columns]. 5265** The SQLITE_DIRECTONLY flags is a security feature which is recommended 5266** for all [application-defined SQL functions], and especially for functions 5267** that have side-effects or that could potentially leak sensitive 5268** information. 5269** </dd> 5270** 5271** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd> 5272** The SQLITE_INNOCUOUS flag means that the function is unlikely 5273** to cause problems even if misused. An innocuous function should have 5274** no side effects and should not depend on any values other than its 5275** input parameters. The [abs|abs() function] is an example of an 5276** innocuous function. 5277** The [load_extension() SQL function] is not innocuous because of its 5278** side effects. 5279** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not 5280** exactly the same. The [random|random() function] is an example of a 5281** function that is innocuous but not deterministic. 5282** <p>Some heightened security settings 5283** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF]) 5284** disable the use of SQL functions inside views and triggers and in 5285** schema structures such as [CHECK constraints], [DEFAULT clauses], 5286** [expression indexes], [partial indexes], and [generated columns] unless 5287** the function is tagged with SQLITE_INNOCUOUS. Most built-in functions 5288** are innocuous. Developers are advised to avoid using the 5289** SQLITE_INNOCUOUS flag for application-defined functions unless the 5290** function has been carefully audited and found to be free of potentially 5291** security-adverse side-effects and information-leaks. 5292** </dd> 5293** 5294** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd> 5295** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call 5296** [sqlite3_value_subtype()] to inspect the sub-types of its arguments. 5297** Specifying this flag makes no difference for scalar or aggregate user 5298** functions. However, if it is not specified for a user-defined window 5299** function, then any sub-types belonging to arguments passed to the window 5300** function may be discarded before the window function is called (i.e. 5301** sqlite3_value_subtype() will always return 0). 5302** </dd> 5303** </dl> 5304*/ 5305#define SQLITE_DETERMINISTIC 0x000000800 5306#define SQLITE_DIRECTONLY 0x000080000 5307#define SQLITE_SUBTYPE 0x000100000 5308#define SQLITE_INNOCUOUS 0x000200000 5309 5310/* 5311** CAPI3REF: Deprecated Functions 5312** DEPRECATED 5313** 5314** These functions are [deprecated]. In order to maintain 5315** backwards compatibility with older code, these functions continue 5316** to be supported. However, new applications should avoid 5317** the use of these functions. To encourage programmers to avoid 5318** these functions, we will not explain what they do. 5319*/ 5320#ifndef SQLITE_OMIT_DEPRECATED 5321SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 5322SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 5323SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 5324SQLITE_DEPRECATED int sqlite3_global_recover(void); 5325SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 5326SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 5327 void*,sqlite3_int64); 5328#endif 5329 5330/* 5331** CAPI3REF: Obtaining SQL Values 5332** METHOD: sqlite3_value 5333** 5334** <b>Summary:</b> 5335** <blockquote><table border=0 cellpadding=0 cellspacing=0> 5336** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 5337** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 5338** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 5339** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 5340** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 5341** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 5342** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 5343** the native byteorder 5344** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 5345** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 5346** <tr><td> <td> <td> 5347** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 5348** or a UTF-8 TEXT in bytes 5349** <tr><td><b>sqlite3_value_bytes16 </b> 5350** <td>→ <td>Size of UTF-16 5351** TEXT in bytes 5352** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 5353** datatype of the value 5354** <tr><td><b>sqlite3_value_numeric_type </b> 5355** <td>→ <td>Best numeric datatype of the value 5356** <tr><td><b>sqlite3_value_nochange </b> 5357** <td>→ <td>True if the column is unchanged in an UPDATE 5358** against a virtual table. 5359** <tr><td><b>sqlite3_value_frombind </b> 5360** <td>→ <td>True if value originated from a [bound parameter] 5361** </table></blockquote> 5362** 5363** <b>Details:</b> 5364** 5365** These routines extract type, size, and content information from 5366** [protected sqlite3_value] objects. Protected sqlite3_value objects 5367** are used to pass parameter information into the functions that 5368** implement [application-defined SQL functions] and [virtual tables]. 5369** 5370** These routines work only with [protected sqlite3_value] objects. 5371** Any attempt to use these routines on an [unprotected sqlite3_value] 5372** is not threadsafe. 5373** 5374** ^These routines work just like the corresponding [column access functions] 5375** except that these routines take a single [protected sqlite3_value] object 5376** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 5377** 5378** ^The sqlite3_value_text16() interface extracts a UTF-16 string 5379** in the native byte-order of the host machine. ^The 5380** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 5381** extract UTF-16 strings as big-endian and little-endian respectively. 5382** 5383** ^If [sqlite3_value] object V was initialized 5384** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 5385** and if X and Y are strings that compare equal according to strcmp(X,Y), 5386** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 5387** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 5388** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5389** 5390** ^(The sqlite3_value_type(V) interface returns the 5391** [SQLITE_INTEGER | datatype code] for the initial datatype of the 5392** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 5393** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 5394** Other interfaces might change the datatype for an sqlite3_value object. 5395** For example, if the datatype is initially SQLITE_INTEGER and 5396** sqlite3_value_text(V) is called to extract a text value for that 5397** integer, then subsequent calls to sqlite3_value_type(V) might return 5398** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 5399** occurs is undefined and may change from one release of SQLite to the next. 5400** 5401** ^(The sqlite3_value_numeric_type() interface attempts to apply 5402** numeric affinity to the value. This means that an attempt is 5403** made to convert the value to an integer or floating point. If 5404** such a conversion is possible without loss of information (in other 5405** words, if the value is a string that looks like a number) 5406** then the conversion is performed. Otherwise no conversion occurs. 5407** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 5408** 5409** ^Within the [xUpdate] method of a [virtual table], the 5410** sqlite3_value_nochange(X) interface returns true if and only if 5411** the column corresponding to X is unchanged by the UPDATE operation 5412** that the xUpdate method call was invoked to implement and if 5413** and the prior [xColumn] method call that was invoked to extracted 5414** the value for that column returned without setting a result (probably 5415** because it queried [sqlite3_vtab_nochange()] and found that the column 5416** was unchanging). ^Within an [xUpdate] method, any value for which 5417** sqlite3_value_nochange(X) is true will in all other respects appear 5418** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 5419** than within an [xUpdate] method call for an UPDATE statement, then 5420** the return value is arbitrary and meaningless. 5421** 5422** ^The sqlite3_value_frombind(X) interface returns non-zero if the 5423** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()] 5424** interfaces. ^If X comes from an SQL literal value, or a table column, 5425** or an expression, then sqlite3_value_frombind(X) returns zero. 5426** 5427** Please pay particular attention to the fact that the pointer returned 5428** from [sqlite3_value_blob()], [sqlite3_value_text()], or 5429** [sqlite3_value_text16()] can be invalidated by a subsequent call to 5430** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 5431** or [sqlite3_value_text16()]. 5432** 5433** These routines must be called from the same thread as 5434** the SQL function that supplied the [sqlite3_value*] parameters. 5435** 5436** As long as the input parameter is correct, these routines can only 5437** fail if an out-of-memory error occurs during a format conversion. 5438** Only the following subset of interfaces are subject to out-of-memory 5439** errors: 5440** 5441** <ul> 5442** <li> sqlite3_value_blob() 5443** <li> sqlite3_value_text() 5444** <li> sqlite3_value_text16() 5445** <li> sqlite3_value_text16le() 5446** <li> sqlite3_value_text16be() 5447** <li> sqlite3_value_bytes() 5448** <li> sqlite3_value_bytes16() 5449** </ul> 5450** 5451** If an out-of-memory error occurs, then the return value from these 5452** routines is the same as if the column had contained an SQL NULL value. 5453** Valid SQL NULL returns can be distinguished from out-of-memory errors 5454** by invoking the [sqlite3_errcode()] immediately after the suspect 5455** return value is obtained and before any 5456** other SQLite interface is called on the same [database connection]. 5457*/ 5458const void *sqlite3_value_blob(sqlite3_value*); 5459double sqlite3_value_double(sqlite3_value*); 5460int sqlite3_value_int(sqlite3_value*); 5461sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 5462void *sqlite3_value_pointer(sqlite3_value*, const char*); 5463const unsigned char *sqlite3_value_text(sqlite3_value*); 5464const void *sqlite3_value_text16(sqlite3_value*); 5465const void *sqlite3_value_text16le(sqlite3_value*); 5466const void *sqlite3_value_text16be(sqlite3_value*); 5467int sqlite3_value_bytes(sqlite3_value*); 5468int sqlite3_value_bytes16(sqlite3_value*); 5469int sqlite3_value_type(sqlite3_value*); 5470int sqlite3_value_numeric_type(sqlite3_value*); 5471int sqlite3_value_nochange(sqlite3_value*); 5472int sqlite3_value_frombind(sqlite3_value*); 5473 5474/* 5475** CAPI3REF: Finding The Subtype Of SQL Values 5476** METHOD: sqlite3_value 5477** 5478** The sqlite3_value_subtype(V) function returns the subtype for 5479** an [application-defined SQL function] argument V. The subtype 5480** information can be used to pass a limited amount of context from 5481** one SQL function to another. Use the [sqlite3_result_subtype()] 5482** routine to set the subtype for the return value of an SQL function. 5483*/ 5484unsigned int sqlite3_value_subtype(sqlite3_value*); 5485 5486/* 5487** CAPI3REF: Copy And Free SQL Values 5488** METHOD: sqlite3_value 5489** 5490** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 5491** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 5492** is a [protected sqlite3_value] object even if the input is not. 5493** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 5494** memory allocation fails. 5495** 5496** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 5497** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 5498** then sqlite3_value_free(V) is a harmless no-op. 5499*/ 5500sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 5501void sqlite3_value_free(sqlite3_value*); 5502 5503/* 5504** CAPI3REF: Obtain Aggregate Function Context 5505** METHOD: sqlite3_context 5506** 5507** Implementations of aggregate SQL functions use this 5508** routine to allocate memory for storing their state. 5509** 5510** ^The first time the sqlite3_aggregate_context(C,N) routine is called 5511** for a particular aggregate function, SQLite allocates 5512** N bytes of memory, zeroes out that memory, and returns a pointer 5513** to the new memory. ^On second and subsequent calls to 5514** sqlite3_aggregate_context() for the same aggregate function instance, 5515** the same buffer is returned. Sqlite3_aggregate_context() is normally 5516** called once for each invocation of the xStep callback and then one 5517** last time when the xFinal callback is invoked. ^(When no rows match 5518** an aggregate query, the xStep() callback of the aggregate function 5519** implementation is never called and xFinal() is called exactly once. 5520** In those cases, sqlite3_aggregate_context() might be called for the 5521** first time from within xFinal().)^ 5522** 5523** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 5524** when first called if N is less than or equal to zero or if a memory 5525** allocate error occurs. 5526** 5527** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 5528** determined by the N parameter on first successful call. Changing the 5529** value of N in any subsequent call to sqlite3_aggregate_context() within 5530** the same aggregate function instance will not resize the memory 5531** allocation.)^ Within the xFinal callback, it is customary to set 5532** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 5533** pointless memory allocations occur. 5534** 5535** ^SQLite automatically frees the memory allocated by 5536** sqlite3_aggregate_context() when the aggregate query concludes. 5537** 5538** The first parameter must be a copy of the 5539** [sqlite3_context | SQL function context] that is the first parameter 5540** to the xStep or xFinal callback routine that implements the aggregate 5541** function. 5542** 5543** This routine must be called from the same thread in which 5544** the aggregate SQL function is running. 5545*/ 5546void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 5547 5548/* 5549** CAPI3REF: User Data For Functions 5550** METHOD: sqlite3_context 5551** 5552** ^The sqlite3_user_data() interface returns a copy of 5553** the pointer that was the pUserData parameter (the 5th parameter) 5554** of the [sqlite3_create_function()] 5555** and [sqlite3_create_function16()] routines that originally 5556** registered the application defined function. 5557** 5558** This routine must be called from the same thread in which 5559** the application-defined function is running. 5560*/ 5561void *sqlite3_user_data(sqlite3_context*); 5562 5563/* 5564** CAPI3REF: Database Connection For Functions 5565** METHOD: sqlite3_context 5566** 5567** ^The sqlite3_context_db_handle() interface returns a copy of 5568** the pointer to the [database connection] (the 1st parameter) 5569** of the [sqlite3_create_function()] 5570** and [sqlite3_create_function16()] routines that originally 5571** registered the application defined function. 5572*/ 5573sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 5574 5575/* 5576** CAPI3REF: Function Auxiliary Data 5577** METHOD: sqlite3_context 5578** 5579** These functions may be used by (non-aggregate) SQL functions to 5580** associate metadata with argument values. If the same value is passed to 5581** multiple invocations of the same SQL function during query execution, under 5582** some circumstances the associated metadata may be preserved. An example 5583** of where this might be useful is in a regular-expression matching 5584** function. The compiled version of the regular expression can be stored as 5585** metadata associated with the pattern string. 5586** Then as long as the pattern string remains the same, 5587** the compiled regular expression can be reused on multiple 5588** invocations of the same function. 5589** 5590** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 5591** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 5592** value to the application-defined function. ^N is zero for the left-most 5593** function argument. ^If there is no metadata 5594** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 5595** returns a NULL pointer. 5596** 5597** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 5598** argument of the application-defined function. ^Subsequent 5599** calls to sqlite3_get_auxdata(C,N) return P from the most recent 5600** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5601** NULL if the metadata has been discarded. 5602** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5603** SQLite will invoke the destructor function X with parameter P exactly 5604** once, when the metadata is discarded. 5605** SQLite is free to discard the metadata at any time, including: <ul> 5606** <li> ^(when the corresponding function parameter changes)^, or 5607** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5608** SQL statement)^, or 5609** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5610** parameter)^, or 5611** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5612** allocation error occurs.)^ </ul> 5613** 5614** Note the last bullet in particular. The destructor X in 5615** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5616** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5617** should be called near the end of the function implementation and the 5618** function implementation should not make any use of P after 5619** sqlite3_set_auxdata() has been called. 5620** 5621** ^(In practice, metadata is preserved between function calls for 5622** function parameters that are compile-time constants, including literal 5623** values and [parameters] and expressions composed from the same.)^ 5624** 5625** The value of the N parameter to these interfaces should be non-negative. 5626** Future enhancements may make use of negative N values to define new 5627** kinds of function caching behavior. 5628** 5629** These routines must be called from the same thread in which 5630** the SQL function is running. 5631*/ 5632void *sqlite3_get_auxdata(sqlite3_context*, int N); 5633void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5634 5635 5636/* 5637** CAPI3REF: Constants Defining Special Destructor Behavior 5638** 5639** These are special values for the destructor that is passed in as the 5640** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5641** argument is SQLITE_STATIC, it means that the content pointer is constant 5642** and will never change. It does not need to be destroyed. ^The 5643** SQLITE_TRANSIENT value means that the content will likely change in 5644** the near future and that SQLite should make its own private copy of 5645** the content before returning. 5646** 5647** The typedef is necessary to work around problems in certain 5648** C++ compilers. 5649*/ 5650typedef void (*sqlite3_destructor_type)(void*); 5651#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5652#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5653 5654/* 5655** CAPI3REF: Setting The Result Of An SQL Function 5656** METHOD: sqlite3_context 5657** 5658** These routines are used by the xFunc or xFinal callbacks that 5659** implement SQL functions and aggregates. See 5660** [sqlite3_create_function()] and [sqlite3_create_function16()] 5661** for additional information. 5662** 5663** These functions work very much like the [parameter binding] family of 5664** functions used to bind values to host parameters in prepared statements. 5665** Refer to the [SQL parameter] documentation for additional information. 5666** 5667** ^The sqlite3_result_blob() interface sets the result from 5668** an application-defined function to be the BLOB whose content is pointed 5669** to by the second parameter and which is N bytes long where N is the 5670** third parameter. 5671** 5672** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5673** interfaces set the result of the application-defined function to be 5674** a BLOB containing all zero bytes and N bytes in size. 5675** 5676** ^The sqlite3_result_double() interface sets the result from 5677** an application-defined function to be a floating point value specified 5678** by its 2nd argument. 5679** 5680** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5681** cause the implemented SQL function to throw an exception. 5682** ^SQLite uses the string pointed to by the 5683** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5684** as the text of an error message. ^SQLite interprets the error 5685** message string from sqlite3_result_error() as UTF-8. ^SQLite 5686** interprets the string from sqlite3_result_error16() as UTF-16 using 5687** the same [byte-order determination rules] as [sqlite3_bind_text16()]. 5688** ^If the third parameter to sqlite3_result_error() 5689** or sqlite3_result_error16() is negative then SQLite takes as the error 5690** message all text up through the first zero character. 5691** ^If the third parameter to sqlite3_result_error() or 5692** sqlite3_result_error16() is non-negative then SQLite takes that many 5693** bytes (not characters) from the 2nd parameter as the error message. 5694** ^The sqlite3_result_error() and sqlite3_result_error16() 5695** routines make a private copy of the error message text before 5696** they return. Hence, the calling function can deallocate or 5697** modify the text after they return without harm. 5698** ^The sqlite3_result_error_code() function changes the error code 5699** returned by SQLite as a result of an error in a function. ^By default, 5700** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5701** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5702** 5703** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5704** error indicating that a string or BLOB is too long to represent. 5705** 5706** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5707** error indicating that a memory allocation failed. 5708** 5709** ^The sqlite3_result_int() interface sets the return value 5710** of the application-defined function to be the 32-bit signed integer 5711** value given in the 2nd argument. 5712** ^The sqlite3_result_int64() interface sets the return value 5713** of the application-defined function to be the 64-bit signed integer 5714** value given in the 2nd argument. 5715** 5716** ^The sqlite3_result_null() interface sets the return value 5717** of the application-defined function to be NULL. 5718** 5719** ^The sqlite3_result_text(), sqlite3_result_text16(), 5720** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5721** set the return value of the application-defined function to be 5722** a text string which is represented as UTF-8, UTF-16 native byte order, 5723** UTF-16 little endian, or UTF-16 big endian, respectively. 5724** ^The sqlite3_result_text64() interface sets the return value of an 5725** application-defined function to be a text string in an encoding 5726** specified by the fifth (and last) parameter, which must be one 5727** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5728** ^SQLite takes the text result from the application from 5729** the 2nd parameter of the sqlite3_result_text* interfaces. 5730** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5731** is negative, then SQLite takes result text from the 2nd parameter 5732** through the first zero character. 5733** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5734** is non-negative, then as many bytes (not characters) of the text 5735** pointed to by the 2nd parameter are taken as the application-defined 5736** function result. If the 3rd parameter is non-negative, then it 5737** must be the byte offset into the string where the NUL terminator would 5738** appear if the string where NUL terminated. If any NUL characters occur 5739** in the string at a byte offset that is less than the value of the 3rd 5740** parameter, then the resulting string will contain embedded NULs and the 5741** result of expressions operating on strings with embedded NULs is undefined. 5742** ^If the 4th parameter to the sqlite3_result_text* interfaces 5743** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5744** function as the destructor on the text or BLOB result when it has 5745** finished using that result. 5746** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5747** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5748** assumes that the text or BLOB result is in constant space and does not 5749** copy the content of the parameter nor call a destructor on the content 5750** when it has finished using that result. 5751** ^If the 4th parameter to the sqlite3_result_text* interfaces 5752** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5753** then SQLite makes a copy of the result into space obtained 5754** from [sqlite3_malloc()] before it returns. 5755** 5756** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and 5757** sqlite3_result_text16be() routines, and for sqlite3_result_text64() 5758** when the encoding is not UTF8, if the input UTF16 begins with a 5759** byte-order mark (BOM, U+FEFF) then the BOM is removed from the 5760** string and the rest of the string is interpreted according to the 5761** byte-order specified by the BOM. ^The byte-order specified by 5762** the BOM at the beginning of the text overrides the byte-order 5763** specified by the interface procedure. ^So, for example, if 5764** sqlite3_result_text16le() is invoked with text that begins 5765** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the 5766** first two bytes of input are skipped and the remaining input 5767** is interpreted as UTF16BE text. 5768** 5769** ^For UTF16 input text to the sqlite3_result_text16(), 5770** sqlite3_result_text16be(), sqlite3_result_text16le(), and 5771** sqlite3_result_text64() routines, if the text contains invalid 5772** UTF16 characters, the invalid characters might be converted 5773** into the unicode replacement character, U+FFFD. 5774** 5775** ^The sqlite3_result_value() interface sets the result of 5776** the application-defined function to be a copy of the 5777** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5778** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5779** so that the [sqlite3_value] specified in the parameter may change or 5780** be deallocated after sqlite3_result_value() returns without harm. 5781** ^A [protected sqlite3_value] object may always be used where an 5782** [unprotected sqlite3_value] object is required, so either 5783** kind of [sqlite3_value] object can be used with this interface. 5784** 5785** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5786** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5787** also associates the host-language pointer P or type T with that 5788** NULL value such that the pointer can be retrieved within an 5789** [application-defined SQL function] using [sqlite3_value_pointer()]. 5790** ^If the D parameter is not NULL, then it is a pointer to a destructor 5791** for the P parameter. ^SQLite invokes D with P as its only argument 5792** when SQLite is finished with P. The T parameter should be a static 5793** string and preferably a string literal. The sqlite3_result_pointer() 5794** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5795** 5796** If these routines are called from within the different thread 5797** than the one containing the application-defined function that received 5798** the [sqlite3_context] pointer, the results are undefined. 5799*/ 5800void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5801void sqlite3_result_blob64(sqlite3_context*,const void*, 5802 sqlite3_uint64,void(*)(void*)); 5803void sqlite3_result_double(sqlite3_context*, double); 5804void sqlite3_result_error(sqlite3_context*, const char*, int); 5805void sqlite3_result_error16(sqlite3_context*, const void*, int); 5806void sqlite3_result_error_toobig(sqlite3_context*); 5807void sqlite3_result_error_nomem(sqlite3_context*); 5808void sqlite3_result_error_code(sqlite3_context*, int); 5809void sqlite3_result_int(sqlite3_context*, int); 5810void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5811void sqlite3_result_null(sqlite3_context*); 5812void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5813void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5814 void(*)(void*), unsigned char encoding); 5815void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5816void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5817void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5818void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5819void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5820void sqlite3_result_zeroblob(sqlite3_context*, int n); 5821int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5822 5823 5824/* 5825** CAPI3REF: Setting The Subtype Of An SQL Function 5826** METHOD: sqlite3_context 5827** 5828** The sqlite3_result_subtype(C,T) function causes the subtype of 5829** the result from the [application-defined SQL function] with 5830** [sqlite3_context] C to be the value T. Only the lower 8 bits 5831** of the subtype T are preserved in current versions of SQLite; 5832** higher order bits are discarded. 5833** The number of subtype bytes preserved by SQLite might increase 5834** in future releases of SQLite. 5835*/ 5836void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5837 5838/* 5839** CAPI3REF: Define New Collating Sequences 5840** METHOD: sqlite3 5841** 5842** ^These functions add, remove, or modify a [collation] associated 5843** with the [database connection] specified as the first argument. 5844** 5845** ^The name of the collation is a UTF-8 string 5846** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5847** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5848** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5849** considered to be the same name. 5850** 5851** ^(The third argument (eTextRep) must be one of the constants: 5852** <ul> 5853** <li> [SQLITE_UTF8], 5854** <li> [SQLITE_UTF16LE], 5855** <li> [SQLITE_UTF16BE], 5856** <li> [SQLITE_UTF16], or 5857** <li> [SQLITE_UTF16_ALIGNED]. 5858** </ul>)^ 5859** ^The eTextRep argument determines the encoding of strings passed 5860** to the collating function callback, xCompare. 5861** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5862** force strings to be UTF16 with native byte order. 5863** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5864** on an even byte address. 5865** 5866** ^The fourth argument, pArg, is an application data pointer that is passed 5867** through as the first argument to the collating function callback. 5868** 5869** ^The fifth argument, xCompare, is a pointer to the collating function. 5870** ^Multiple collating functions can be registered using the same name but 5871** with different eTextRep parameters and SQLite will use whichever 5872** function requires the least amount of data transformation. 5873** ^If the xCompare argument is NULL then the collating function is 5874** deleted. ^When all collating functions having the same name are deleted, 5875** that collation is no longer usable. 5876** 5877** ^The collating function callback is invoked with a copy of the pArg 5878** application data pointer and with two strings in the encoding specified 5879** by the eTextRep argument. The two integer parameters to the collating 5880** function callback are the length of the two strings, in bytes. The collating 5881** function must return an integer that is negative, zero, or positive 5882** if the first string is less than, equal to, or greater than the second, 5883** respectively. A collating function must always return the same answer 5884** given the same inputs. If two or more collating functions are registered 5885** to the same collation name (using different eTextRep values) then all 5886** must give an equivalent answer when invoked with equivalent strings. 5887** The collating function must obey the following properties for all 5888** strings A, B, and C: 5889** 5890** <ol> 5891** <li> If A==B then B==A. 5892** <li> If A==B and B==C then A==C. 5893** <li> If A<B THEN B>A. 5894** <li> If A<B and B<C then A<C. 5895** </ol> 5896** 5897** If a collating function fails any of the above constraints and that 5898** collating function is registered and used, then the behavior of SQLite 5899** is undefined. 5900** 5901** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5902** with the addition that the xDestroy callback is invoked on pArg when 5903** the collating function is deleted. 5904** ^Collating functions are deleted when they are overridden by later 5905** calls to the collation creation functions or when the 5906** [database connection] is closed using [sqlite3_close()]. 5907** 5908** ^The xDestroy callback is <u>not</u> called if the 5909** sqlite3_create_collation_v2() function fails. Applications that invoke 5910** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5911** check the return code and dispose of the application data pointer 5912** themselves rather than expecting SQLite to deal with it for them. 5913** This is different from every other SQLite interface. The inconsistency 5914** is unfortunate but cannot be changed without breaking backwards 5915** compatibility. 5916** 5917** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5918*/ 5919int sqlite3_create_collation( 5920 sqlite3*, 5921 const char *zName, 5922 int eTextRep, 5923 void *pArg, 5924 int(*xCompare)(void*,int,const void*,int,const void*) 5925); 5926int sqlite3_create_collation_v2( 5927 sqlite3*, 5928 const char *zName, 5929 int eTextRep, 5930 void *pArg, 5931 int(*xCompare)(void*,int,const void*,int,const void*), 5932 void(*xDestroy)(void*) 5933); 5934int sqlite3_create_collation16( 5935 sqlite3*, 5936 const void *zName, 5937 int eTextRep, 5938 void *pArg, 5939 int(*xCompare)(void*,int,const void*,int,const void*) 5940); 5941 5942/* 5943** CAPI3REF: Collation Needed Callbacks 5944** METHOD: sqlite3 5945** 5946** ^To avoid having to register all collation sequences before a database 5947** can be used, a single callback function may be registered with the 5948** [database connection] to be invoked whenever an undefined collation 5949** sequence is required. 5950** 5951** ^If the function is registered using the sqlite3_collation_needed() API, 5952** then it is passed the names of undefined collation sequences as strings 5953** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5954** the names are passed as UTF-16 in machine native byte order. 5955** ^A call to either function replaces the existing collation-needed callback. 5956** 5957** ^(When the callback is invoked, the first argument passed is a copy 5958** of the second argument to sqlite3_collation_needed() or 5959** sqlite3_collation_needed16(). The second argument is the database 5960** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5961** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5962** sequence function required. The fourth parameter is the name of the 5963** required collation sequence.)^ 5964** 5965** The callback function should register the desired collation using 5966** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5967** [sqlite3_create_collation_v2()]. 5968*/ 5969int sqlite3_collation_needed( 5970 sqlite3*, 5971 void*, 5972 void(*)(void*,sqlite3*,int eTextRep,const char*) 5973); 5974int sqlite3_collation_needed16( 5975 sqlite3*, 5976 void*, 5977 void(*)(void*,sqlite3*,int eTextRep,const void*) 5978); 5979 5980#ifdef SQLITE_ENABLE_CEROD 5981/* 5982** Specify the activation key for a CEROD database. Unless 5983** activated, none of the CEROD routines will work. 5984*/ 5985void sqlite3_activate_cerod( 5986 const char *zPassPhrase /* Activation phrase */ 5987); 5988#endif 5989 5990/* 5991** CAPI3REF: Suspend Execution For A Short Time 5992** 5993** The sqlite3_sleep() function causes the current thread to suspend execution 5994** for at least a number of milliseconds specified in its parameter. 5995** 5996** If the operating system does not support sleep requests with 5997** millisecond time resolution, then the time will be rounded up to 5998** the nearest second. The number of milliseconds of sleep actually 5999** requested from the operating system is returned. 6000** 6001** ^SQLite implements this interface by calling the xSleep() 6002** method of the default [sqlite3_vfs] object. If the xSleep() method 6003** of the default VFS is not implemented correctly, or not implemented at 6004** all, then the behavior of sqlite3_sleep() may deviate from the description 6005** in the previous paragraphs. 6006*/ 6007int sqlite3_sleep(int); 6008 6009/* 6010** CAPI3REF: Name Of The Folder Holding Temporary Files 6011** 6012** ^(If this global variable is made to point to a string which is 6013** the name of a folder (a.k.a. directory), then all temporary files 6014** created by SQLite when using a built-in [sqlite3_vfs | VFS] 6015** will be placed in that directory.)^ ^If this variable 6016** is a NULL pointer, then SQLite performs a search for an appropriate 6017** temporary file directory. 6018** 6019** Applications are strongly discouraged from using this global variable. 6020** It is required to set a temporary folder on Windows Runtime (WinRT). 6021** But for all other platforms, it is highly recommended that applications 6022** neither read nor write this variable. This global variable is a relic 6023** that exists for backwards compatibility of legacy applications and should 6024** be avoided in new projects. 6025** 6026** It is not safe to read or modify this variable in more than one 6027** thread at a time. It is not safe to read or modify this variable 6028** if a [database connection] is being used at the same time in a separate 6029** thread. 6030** It is intended that this variable be set once 6031** as part of process initialization and before any SQLite interface 6032** routines have been called and that this variable remain unchanged 6033** thereafter. 6034** 6035** ^The [temp_store_directory pragma] may modify this variable and cause 6036** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6037** the [temp_store_directory pragma] always assumes that any string 6038** that this variable points to is held in memory obtained from 6039** [sqlite3_malloc] and the pragma may attempt to free that memory 6040** using [sqlite3_free]. 6041** Hence, if this variable is modified directly, either it should be 6042** made NULL or made to point to memory obtained from [sqlite3_malloc] 6043** or else the use of the [temp_store_directory pragma] should be avoided. 6044** Except when requested by the [temp_store_directory pragma], SQLite 6045** does not free the memory that sqlite3_temp_directory points to. If 6046** the application wants that memory to be freed, it must do 6047** so itself, taking care to only do so after all [database connection] 6048** objects have been destroyed. 6049** 6050** <b>Note to Windows Runtime users:</b> The temporary directory must be set 6051** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 6052** features that require the use of temporary files may fail. Here is an 6053** example of how to do this using C++ with the Windows Runtime: 6054** 6055** <blockquote><pre> 6056** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 6057** TemporaryFolder->Path->Data(); 6058** char zPathBuf[MAX_PATH + 1]; 6059** memset(zPathBuf, 0, sizeof(zPathBuf)); 6060** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 6061** NULL, NULL); 6062** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 6063** </pre></blockquote> 6064*/ 6065SQLITE_EXTERN char *sqlite3_temp_directory; 6066 6067/* 6068** CAPI3REF: Name Of The Folder Holding Database Files 6069** 6070** ^(If this global variable is made to point to a string which is 6071** the name of a folder (a.k.a. directory), then all database files 6072** specified with a relative pathname and created or accessed by 6073** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 6074** to be relative to that directory.)^ ^If this variable is a NULL 6075** pointer, then SQLite assumes that all database files specified 6076** with a relative pathname are relative to the current directory 6077** for the process. Only the windows VFS makes use of this global 6078** variable; it is ignored by the unix VFS. 6079** 6080** Changing the value of this variable while a database connection is 6081** open can result in a corrupt database. 6082** 6083** It is not safe to read or modify this variable in more than one 6084** thread at a time. It is not safe to read or modify this variable 6085** if a [database connection] is being used at the same time in a separate 6086** thread. 6087** It is intended that this variable be set once 6088** as part of process initialization and before any SQLite interface 6089** routines have been called and that this variable remain unchanged 6090** thereafter. 6091** 6092** ^The [data_store_directory pragma] may modify this variable and cause 6093** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6094** the [data_store_directory pragma] always assumes that any string 6095** that this variable points to is held in memory obtained from 6096** [sqlite3_malloc] and the pragma may attempt to free that memory 6097** using [sqlite3_free]. 6098** Hence, if this variable is modified directly, either it should be 6099** made NULL or made to point to memory obtained from [sqlite3_malloc] 6100** or else the use of the [data_store_directory pragma] should be avoided. 6101*/ 6102SQLITE_EXTERN char *sqlite3_data_directory; 6103 6104/* 6105** CAPI3REF: Win32 Specific Interface 6106** 6107** These interfaces are available only on Windows. The 6108** [sqlite3_win32_set_directory] interface is used to set the value associated 6109** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to 6110** zValue, depending on the value of the type parameter. The zValue parameter 6111** should be NULL to cause the previous value to be freed via [sqlite3_free]; 6112** a non-NULL value will be copied into memory obtained from [sqlite3_malloc] 6113** prior to being used. The [sqlite3_win32_set_directory] interface returns 6114** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported, 6115** or [SQLITE_NOMEM] if memory could not be allocated. The value of the 6116** [sqlite3_data_directory] variable is intended to act as a replacement for 6117** the current directory on the sub-platforms of Win32 where that concept is 6118** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and 6119** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the 6120** sqlite3_win32_set_directory interface except the string parameter must be 6121** UTF-8 or UTF-16, respectively. 6122*/ 6123int sqlite3_win32_set_directory( 6124 unsigned long type, /* Identifier for directory being set or reset */ 6125 void *zValue /* New value for directory being set or reset */ 6126); 6127int sqlite3_win32_set_directory8(unsigned long type, const char *zValue); 6128int sqlite3_win32_set_directory16(unsigned long type, const void *zValue); 6129 6130/* 6131** CAPI3REF: Win32 Directory Types 6132** 6133** These macros are only available on Windows. They define the allowed values 6134** for the type argument to the [sqlite3_win32_set_directory] interface. 6135*/ 6136#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1 6137#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2 6138 6139/* 6140** CAPI3REF: Test For Auto-Commit Mode 6141** KEYWORDS: {autocommit mode} 6142** METHOD: sqlite3 6143** 6144** ^The sqlite3_get_autocommit() interface returns non-zero or 6145** zero if the given database connection is or is not in autocommit mode, 6146** respectively. ^Autocommit mode is on by default. 6147** ^Autocommit mode is disabled by a [BEGIN] statement. 6148** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 6149** 6150** If certain kinds of errors occur on a statement within a multi-statement 6151** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 6152** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 6153** transaction might be rolled back automatically. The only way to 6154** find out whether SQLite automatically rolled back the transaction after 6155** an error is to use this function. 6156** 6157** If another thread changes the autocommit status of the database 6158** connection while this routine is running, then the return value 6159** is undefined. 6160*/ 6161int sqlite3_get_autocommit(sqlite3*); 6162 6163/* 6164** CAPI3REF: Find The Database Handle Of A Prepared Statement 6165** METHOD: sqlite3_stmt 6166** 6167** ^The sqlite3_db_handle interface returns the [database connection] handle 6168** to which a [prepared statement] belongs. ^The [database connection] 6169** returned by sqlite3_db_handle is the same [database connection] 6170** that was the first argument 6171** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 6172** create the statement in the first place. 6173*/ 6174sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 6175 6176/* 6177** CAPI3REF: Return The Filename For A Database Connection 6178** METHOD: sqlite3 6179** 6180** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename 6181** associated with database N of connection D. 6182** ^If there is no attached database N on the database 6183** connection D, or if database N is a temporary or in-memory database, then 6184** this function will return either a NULL pointer or an empty string. 6185** 6186** ^The string value returned by this routine is owned and managed by 6187** the database connection. ^The value will be valid until the database N 6188** is [DETACH]-ed or until the database connection closes. 6189** 6190** ^The filename returned by this function is the output of the 6191** xFullPathname method of the [VFS]. ^In other words, the filename 6192** will be an absolute pathname, even if the filename used 6193** to open the database originally was a URI or relative pathname. 6194** 6195** If the filename pointer returned by this routine is not NULL, then it 6196** can be used as the filename input parameter to these routines: 6197** <ul> 6198** <li> [sqlite3_uri_parameter()] 6199** <li> [sqlite3_uri_boolean()] 6200** <li> [sqlite3_uri_int64()] 6201** <li> [sqlite3_filename_database()] 6202** <li> [sqlite3_filename_journal()] 6203** <li> [sqlite3_filename_wal()] 6204** </ul> 6205*/ 6206const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 6207 6208/* 6209** CAPI3REF: Determine if a database is read-only 6210** METHOD: sqlite3 6211** 6212** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 6213** of connection D is read-only, 0 if it is read/write, or -1 if N is not 6214** the name of a database on connection D. 6215*/ 6216int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 6217 6218/* 6219** CAPI3REF: Determine the transaction state of a database 6220** METHOD: sqlite3 6221** 6222** ^The sqlite3_txn_state(D,S) interface returns the current 6223** [transaction state] of schema S in database connection D. ^If S is NULL, 6224** then the highest transaction state of any schema on database connection D 6225** is returned. Transaction states are (in order of lowest to highest): 6226** <ol> 6227** <li value="0"> SQLITE_TXN_NONE 6228** <li value="1"> SQLITE_TXN_READ 6229** <li value="2"> SQLITE_TXN_WRITE 6230** </ol> 6231** ^If the S argument to sqlite3_txn_state(D,S) is not the name of 6232** a valid schema, then -1 is returned. 6233*/ 6234int sqlite3_txn_state(sqlite3*,const char *zSchema); 6235 6236/* 6237** CAPI3REF: Allowed return values from [sqlite3_txn_state()] 6238** KEYWORDS: {transaction state} 6239** 6240** These constants define the current transaction state of a database file. 6241** ^The [sqlite3_txn_state(D,S)] interface returns one of these 6242** constants in order to describe the transaction state of schema S 6243** in [database connection] D. 6244** 6245** <dl> 6246** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt> 6247** <dd>The SQLITE_TXN_NONE state means that no transaction is currently 6248** pending.</dd> 6249** 6250** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt> 6251** <dd>The SQLITE_TXN_READ state means that the database is currently 6252** in a read transaction. Content has been read from the database file 6253** but nothing in the database file has changed. The transaction state 6254** will advanced to SQLITE_TXN_WRITE if any changes occur and there are 6255** no other conflicting concurrent write transactions. The transaction 6256** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or 6257** [COMMIT].</dd> 6258** 6259** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt> 6260** <dd>The SQLITE_TXN_WRITE state means that the database is currently 6261** in a write transaction. Content has been written to the database file 6262** but has not yet committed. The transaction state will change to 6263** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd> 6264*/ 6265#define SQLITE_TXN_NONE 0 6266#define SQLITE_TXN_READ 1 6267#define SQLITE_TXN_WRITE 2 6268 6269/* 6270** CAPI3REF: Find the next prepared statement 6271** METHOD: sqlite3 6272** 6273** ^This interface returns a pointer to the next [prepared statement] after 6274** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 6275** then this interface returns a pointer to the first prepared statement 6276** associated with the database connection pDb. ^If no prepared statement 6277** satisfies the conditions of this routine, it returns NULL. 6278** 6279** The [database connection] pointer D in a call to 6280** [sqlite3_next_stmt(D,S)] must refer to an open database 6281** connection and in particular must not be a NULL pointer. 6282*/ 6283sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 6284 6285/* 6286** CAPI3REF: Commit And Rollback Notification Callbacks 6287** METHOD: sqlite3 6288** 6289** ^The sqlite3_commit_hook() interface registers a callback 6290** function to be invoked whenever a transaction is [COMMIT | committed]. 6291** ^Any callback set by a previous call to sqlite3_commit_hook() 6292** for the same database connection is overridden. 6293** ^The sqlite3_rollback_hook() interface registers a callback 6294** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 6295** ^Any callback set by a previous call to sqlite3_rollback_hook() 6296** for the same database connection is overridden. 6297** ^The pArg argument is passed through to the callback. 6298** ^If the callback on a commit hook function returns non-zero, 6299** then the commit is converted into a rollback. 6300** 6301** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 6302** return the P argument from the previous call of the same function 6303** on the same [database connection] D, or NULL for 6304** the first call for each function on D. 6305** 6306** The commit and rollback hook callbacks are not reentrant. 6307** The callback implementation must not do anything that will modify 6308** the database connection that invoked the callback. Any actions 6309** to modify the database connection must be deferred until after the 6310** completion of the [sqlite3_step()] call that triggered the commit 6311** or rollback hook in the first place. 6312** Note that running any other SQL statements, including SELECT statements, 6313** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 6314** the database connections for the meaning of "modify" in this paragraph. 6315** 6316** ^Registering a NULL function disables the callback. 6317** 6318** ^When the commit hook callback routine returns zero, the [COMMIT] 6319** operation is allowed to continue normally. ^If the commit hook 6320** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 6321** ^The rollback hook is invoked on a rollback that results from a commit 6322** hook returning non-zero, just as it would be with any other rollback. 6323** 6324** ^For the purposes of this API, a transaction is said to have been 6325** rolled back if an explicit "ROLLBACK" statement is executed, or 6326** an error or constraint causes an implicit rollback to occur. 6327** ^The rollback callback is not invoked if a transaction is 6328** automatically rolled back because the database connection is closed. 6329** 6330** See also the [sqlite3_update_hook()] interface. 6331*/ 6332void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 6333void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 6334 6335/* 6336** CAPI3REF: Data Change Notification Callbacks 6337** METHOD: sqlite3 6338** 6339** ^The sqlite3_update_hook() interface registers a callback function 6340** with the [database connection] identified by the first argument 6341** to be invoked whenever a row is updated, inserted or deleted in 6342** a [rowid table]. 6343** ^Any callback set by a previous call to this function 6344** for the same database connection is overridden. 6345** 6346** ^The second argument is a pointer to the function to invoke when a 6347** row is updated, inserted or deleted in a rowid table. 6348** ^The first argument to the callback is a copy of the third argument 6349** to sqlite3_update_hook(). 6350** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 6351** or [SQLITE_UPDATE], depending on the operation that caused the callback 6352** to be invoked. 6353** ^The third and fourth arguments to the callback contain pointers to the 6354** database and table name containing the affected row. 6355** ^The final callback parameter is the [rowid] of the row. 6356** ^In the case of an update, this is the [rowid] after the update takes place. 6357** 6358** ^(The update hook is not invoked when internal system tables are 6359** modified (i.e. sqlite_sequence).)^ 6360** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 6361** 6362** ^In the current implementation, the update hook 6363** is not invoked when conflicting rows are deleted because of an 6364** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 6365** invoked when rows are deleted using the [truncate optimization]. 6366** The exceptions defined in this paragraph might change in a future 6367** release of SQLite. 6368** 6369** The update hook implementation must not do anything that will modify 6370** the database connection that invoked the update hook. Any actions 6371** to modify the database connection must be deferred until after the 6372** completion of the [sqlite3_step()] call that triggered the update hook. 6373** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 6374** database connections for the meaning of "modify" in this paragraph. 6375** 6376** ^The sqlite3_update_hook(D,C,P) function 6377** returns the P argument from the previous call 6378** on the same [database connection] D, or NULL for 6379** the first call on D. 6380** 6381** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 6382** and [sqlite3_preupdate_hook()] interfaces. 6383*/ 6384void *sqlite3_update_hook( 6385 sqlite3*, 6386 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 6387 void* 6388); 6389 6390/* 6391** CAPI3REF: Enable Or Disable Shared Pager Cache 6392** 6393** ^(This routine enables or disables the sharing of the database cache 6394** and schema data structures between [database connection | connections] 6395** to the same database. Sharing is enabled if the argument is true 6396** and disabled if the argument is false.)^ 6397** 6398** ^Cache sharing is enabled and disabled for an entire process. 6399** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 6400** In prior versions of SQLite, 6401** sharing was enabled or disabled for each thread separately. 6402** 6403** ^(The cache sharing mode set by this interface effects all subsequent 6404** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 6405** Existing database connections continue to use the sharing mode 6406** that was in effect at the time they were opened.)^ 6407** 6408** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 6409** successfully. An [error code] is returned otherwise.)^ 6410** 6411** ^Shared cache is disabled by default. It is recommended that it stay 6412** that way. In other words, do not use this routine. This interface 6413** continues to be provided for historical compatibility, but its use is 6414** discouraged. Any use of shared cache is discouraged. If shared cache 6415** must be used, it is recommended that shared cache only be enabled for 6416** individual database connections using the [sqlite3_open_v2()] interface 6417** with the [SQLITE_OPEN_SHAREDCACHE] flag. 6418** 6419** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 6420** and will always return SQLITE_MISUSE. On those systems, 6421** shared cache mode should be enabled per-database connection via 6422** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 6423** 6424** This interface is threadsafe on processors where writing a 6425** 32-bit integer is atomic. 6426** 6427** See Also: [SQLite Shared-Cache Mode] 6428*/ 6429int sqlite3_enable_shared_cache(int); 6430 6431/* 6432** CAPI3REF: Attempt To Free Heap Memory 6433** 6434** ^The sqlite3_release_memory() interface attempts to free N bytes 6435** of heap memory by deallocating non-essential memory allocations 6436** held by the database library. Memory used to cache database 6437** pages to improve performance is an example of non-essential memory. 6438** ^sqlite3_release_memory() returns the number of bytes actually freed, 6439** which might be more or less than the amount requested. 6440** ^The sqlite3_release_memory() routine is a no-op returning zero 6441** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 6442** 6443** See also: [sqlite3_db_release_memory()] 6444*/ 6445int sqlite3_release_memory(int); 6446 6447/* 6448** CAPI3REF: Free Memory Used By A Database Connection 6449** METHOD: sqlite3 6450** 6451** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 6452** memory as possible from database connection D. Unlike the 6453** [sqlite3_release_memory()] interface, this interface is in effect even 6454** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 6455** omitted. 6456** 6457** See also: [sqlite3_release_memory()] 6458*/ 6459int sqlite3_db_release_memory(sqlite3*); 6460 6461/* 6462** CAPI3REF: Impose A Limit On Heap Size 6463** 6464** These interfaces impose limits on the amount of heap memory that will be 6465** by all database connections within a single process. 6466** 6467** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 6468** soft limit on the amount of heap memory that may be allocated by SQLite. 6469** ^SQLite strives to keep heap memory utilization below the soft heap 6470** limit by reducing the number of pages held in the page cache 6471** as heap memory usages approaches the limit. 6472** ^The soft heap limit is "soft" because even though SQLite strives to stay 6473** below the limit, it will exceed the limit rather than generate 6474** an [SQLITE_NOMEM] error. In other words, the soft heap limit 6475** is advisory only. 6476** 6477** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of 6478** N bytes on the amount of memory that will be allocated. ^The 6479** sqlite3_hard_heap_limit64(N) interface is similar to 6480** sqlite3_soft_heap_limit64(N) except that memory allocations will fail 6481** when the hard heap limit is reached. 6482** 6483** ^The return value from both sqlite3_soft_heap_limit64() and 6484** sqlite3_hard_heap_limit64() is the size of 6485** the heap limit prior to the call, or negative in the case of an 6486** error. ^If the argument N is negative 6487** then no change is made to the heap limit. Hence, the current 6488** size of heap limits can be determined by invoking 6489** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1). 6490** 6491** ^Setting the heap limits to zero disables the heap limiter mechanism. 6492** 6493** ^The soft heap limit may not be greater than the hard heap limit. 6494** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N) 6495** is invoked with a value of N that is greater than the hard heap limit, 6496** the the soft heap limit is set to the value of the hard heap limit. 6497** ^The soft heap limit is automatically enabled whenever the hard heap 6498** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and 6499** the soft heap limit is outside the range of 1..N, then the soft heap 6500** limit is set to N. ^Invoking sqlite3_soft_heap_limit64(0) when the 6501** hard heap limit is enabled makes the soft heap limit equal to the 6502** hard heap limit. 6503** 6504** The memory allocation limits can also be adjusted using 6505** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit]. 6506** 6507** ^(The heap limits are not enforced in the current implementation 6508** if one or more of following conditions are true: 6509** 6510** <ul> 6511** <li> The limit value is set to zero. 6512** <li> Memory accounting is disabled using a combination of the 6513** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 6514** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 6515** <li> An alternative page cache implementation is specified using 6516** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 6517** <li> The page cache allocates from its own memory pool supplied 6518** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 6519** from the heap. 6520** </ul>)^ 6521** 6522** The circumstances under which SQLite will enforce the heap limits may 6523** changes in future releases of SQLite. 6524*/ 6525sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 6526sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N); 6527 6528/* 6529** CAPI3REF: Deprecated Soft Heap Limit Interface 6530** DEPRECATED 6531** 6532** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 6533** interface. This routine is provided for historical compatibility 6534** only. All new applications should use the 6535** [sqlite3_soft_heap_limit64()] interface rather than this one. 6536*/ 6537SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 6538 6539 6540/* 6541** CAPI3REF: Extract Metadata About A Column Of A Table 6542** METHOD: sqlite3 6543** 6544** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 6545** information about column C of table T in database D 6546** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 6547** interface returns SQLITE_OK and fills in the non-NULL pointers in 6548** the final five arguments with appropriate values if the specified 6549** column exists. ^The sqlite3_table_column_metadata() interface returns 6550** SQLITE_ERROR if the specified column does not exist. 6551** ^If the column-name parameter to sqlite3_table_column_metadata() is a 6552** NULL pointer, then this routine simply checks for the existence of the 6553** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 6554** does not. If the table name parameter T in a call to 6555** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 6556** undefined behavior. 6557** 6558** ^The column is identified by the second, third and fourth parameters to 6559** this function. ^(The second parameter is either the name of the database 6560** (i.e. "main", "temp", or an attached database) containing the specified 6561** table or NULL.)^ ^If it is NULL, then all attached databases are searched 6562** for the table using the same algorithm used by the database engine to 6563** resolve unqualified table references. 6564** 6565** ^The third and fourth parameters to this function are the table and column 6566** name of the desired column, respectively. 6567** 6568** ^Metadata is returned by writing to the memory locations passed as the 5th 6569** and subsequent parameters to this function. ^Any of these arguments may be 6570** NULL, in which case the corresponding element of metadata is omitted. 6571** 6572** ^(<blockquote> 6573** <table border="1"> 6574** <tr><th> Parameter <th> Output<br>Type <th> Description 6575** 6576** <tr><td> 5th <td> const char* <td> Data type 6577** <tr><td> 6th <td> const char* <td> Name of default collation sequence 6578** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 6579** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 6580** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 6581** </table> 6582** </blockquote>)^ 6583** 6584** ^The memory pointed to by the character pointers returned for the 6585** declaration type and collation sequence is valid until the next 6586** call to any SQLite API function. 6587** 6588** ^If the specified table is actually a view, an [error code] is returned. 6589** 6590** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 6591** is not a [WITHOUT ROWID] table and an 6592** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 6593** parameters are set for the explicitly declared column. ^(If there is no 6594** [INTEGER PRIMARY KEY] column, then the outputs 6595** for the [rowid] are set as follows: 6596** 6597** <pre> 6598** data type: "INTEGER" 6599** collation sequence: "BINARY" 6600** not null: 0 6601** primary key: 1 6602** auto increment: 0 6603** </pre>)^ 6604** 6605** ^This function causes all database schemas to be read from disk and 6606** parsed, if that has not already been done, and returns an error if 6607** any errors are encountered while loading the schema. 6608*/ 6609int sqlite3_table_column_metadata( 6610 sqlite3 *db, /* Connection handle */ 6611 const char *zDbName, /* Database name or NULL */ 6612 const char *zTableName, /* Table name */ 6613 const char *zColumnName, /* Column name */ 6614 char const **pzDataType, /* OUTPUT: Declared data type */ 6615 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 6616 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 6617 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 6618 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 6619); 6620 6621/* 6622** CAPI3REF: Load An Extension 6623** METHOD: sqlite3 6624** 6625** ^This interface loads an SQLite extension library from the named file. 6626** 6627** ^The sqlite3_load_extension() interface attempts to load an 6628** [SQLite extension] library contained in the file zFile. If 6629** the file cannot be loaded directly, attempts are made to load 6630** with various operating-system specific extensions added. 6631** So for example, if "samplelib" cannot be loaded, then names like 6632** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 6633** be tried also. 6634** 6635** ^The entry point is zProc. 6636** ^(zProc may be 0, in which case SQLite will try to come up with an 6637** entry point name on its own. It first tries "sqlite3_extension_init". 6638** If that does not work, it constructs a name "sqlite3_X_init" where the 6639** X is consists of the lower-case equivalent of all ASCII alphabetic 6640** characters in the filename from the last "/" to the first following 6641** "." and omitting any initial "lib".)^ 6642** ^The sqlite3_load_extension() interface returns 6643** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 6644** ^If an error occurs and pzErrMsg is not 0, then the 6645** [sqlite3_load_extension()] interface shall attempt to 6646** fill *pzErrMsg with error message text stored in memory 6647** obtained from [sqlite3_malloc()]. The calling function 6648** should free this memory by calling [sqlite3_free()]. 6649** 6650** ^Extension loading must be enabled using 6651** [sqlite3_enable_load_extension()] or 6652** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 6653** prior to calling this API, 6654** otherwise an error will be returned. 6655** 6656** <b>Security warning:</b> It is recommended that the 6657** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 6658** interface. The use of the [sqlite3_enable_load_extension()] interface 6659** should be avoided. This will keep the SQL function [load_extension()] 6660** disabled and prevent SQL injections from giving attackers 6661** access to extension loading capabilities. 6662** 6663** See also the [load_extension() SQL function]. 6664*/ 6665int sqlite3_load_extension( 6666 sqlite3 *db, /* Load the extension into this database connection */ 6667 const char *zFile, /* Name of the shared library containing extension */ 6668 const char *zProc, /* Entry point. Derived from zFile if 0 */ 6669 char **pzErrMsg /* Put error message here if not 0 */ 6670); 6671 6672/* 6673** CAPI3REF: Enable Or Disable Extension Loading 6674** METHOD: sqlite3 6675** 6676** ^So as not to open security holes in older applications that are 6677** unprepared to deal with [extension loading], and as a means of disabling 6678** [extension loading] while evaluating user-entered SQL, the following API 6679** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 6680** 6681** ^Extension loading is off by default. 6682** ^Call the sqlite3_enable_load_extension() routine with onoff==1 6683** to turn extension loading on and call it with onoff==0 to turn 6684** it back off again. 6685** 6686** ^This interface enables or disables both the C-API 6687** [sqlite3_load_extension()] and the SQL function [load_extension()]. 6688** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 6689** to enable or disable only the C-API.)^ 6690** 6691** <b>Security warning:</b> It is recommended that extension loading 6692** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 6693** rather than this interface, so the [load_extension()] SQL function 6694** remains disabled. This will prevent SQL injections from giving attackers 6695** access to extension loading capabilities. 6696*/ 6697int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6698 6699/* 6700** CAPI3REF: Automatically Load Statically Linked Extensions 6701** 6702** ^This interface causes the xEntryPoint() function to be invoked for 6703** each new [database connection] that is created. The idea here is that 6704** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6705** that is to be automatically loaded into all new database connections. 6706** 6707** ^(Even though the function prototype shows that xEntryPoint() takes 6708** no arguments and returns void, SQLite invokes xEntryPoint() with three 6709** arguments and expects an integer result as if the signature of the 6710** entry point where as follows: 6711** 6712** <blockquote><pre> 6713** int xEntryPoint( 6714** sqlite3 *db, 6715** const char **pzErrMsg, 6716** const struct sqlite3_api_routines *pThunk 6717** ); 6718** </pre></blockquote>)^ 6719** 6720** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6721** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6722** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6723** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6724** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6725** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6726** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6727** 6728** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6729** on the list of automatic extensions is a harmless no-op. ^No entry point 6730** will be called more than once for each database connection that is opened. 6731** 6732** See also: [sqlite3_reset_auto_extension()] 6733** and [sqlite3_cancel_auto_extension()] 6734*/ 6735int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6736 6737/* 6738** CAPI3REF: Cancel Automatic Extension Loading 6739** 6740** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6741** initialization routine X that was registered using a prior call to 6742** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6743** routine returns 1 if initialization routine X was successfully 6744** unregistered and it returns 0 if X was not on the list of initialization 6745** routines. 6746*/ 6747int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6748 6749/* 6750** CAPI3REF: Reset Automatic Extension Loading 6751** 6752** ^This interface disables all automatic extensions previously 6753** registered using [sqlite3_auto_extension()]. 6754*/ 6755void sqlite3_reset_auto_extension(void); 6756 6757/* 6758** The interface to the virtual-table mechanism is currently considered 6759** to be experimental. The interface might change in incompatible ways. 6760** If this is a problem for you, do not use the interface at this time. 6761** 6762** When the virtual-table mechanism stabilizes, we will declare the 6763** interface fixed, support it indefinitely, and remove this comment. 6764*/ 6765 6766/* 6767** Structures used by the virtual table interface 6768*/ 6769typedef struct sqlite3_vtab sqlite3_vtab; 6770typedef struct sqlite3_index_info sqlite3_index_info; 6771typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6772typedef struct sqlite3_module sqlite3_module; 6773 6774/* 6775** CAPI3REF: Virtual Table Object 6776** KEYWORDS: sqlite3_module {virtual table module} 6777** 6778** This structure, sometimes called a "virtual table module", 6779** defines the implementation of a [virtual table]. 6780** This structure consists mostly of methods for the module. 6781** 6782** ^A virtual table module is created by filling in a persistent 6783** instance of this structure and passing a pointer to that instance 6784** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6785** ^The registration remains valid until it is replaced by a different 6786** module or until the [database connection] closes. The content 6787** of this structure must not change while it is registered with 6788** any database connection. 6789*/ 6790struct sqlite3_module { 6791 int iVersion; 6792 int (*xCreate)(sqlite3*, void *pAux, 6793 int argc, const char *const*argv, 6794 sqlite3_vtab **ppVTab, char**); 6795 int (*xConnect)(sqlite3*, void *pAux, 6796 int argc, const char *const*argv, 6797 sqlite3_vtab **ppVTab, char**); 6798 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6799 int (*xDisconnect)(sqlite3_vtab *pVTab); 6800 int (*xDestroy)(sqlite3_vtab *pVTab); 6801 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6802 int (*xClose)(sqlite3_vtab_cursor*); 6803 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6804 int argc, sqlite3_value **argv); 6805 int (*xNext)(sqlite3_vtab_cursor*); 6806 int (*xEof)(sqlite3_vtab_cursor*); 6807 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6808 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6809 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6810 int (*xBegin)(sqlite3_vtab *pVTab); 6811 int (*xSync)(sqlite3_vtab *pVTab); 6812 int (*xCommit)(sqlite3_vtab *pVTab); 6813 int (*xRollback)(sqlite3_vtab *pVTab); 6814 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6815 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6816 void **ppArg); 6817 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6818 /* The methods above are in version 1 of the sqlite_module object. Those 6819 ** below are for version 2 and greater. */ 6820 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6821 int (*xRelease)(sqlite3_vtab *pVTab, int); 6822 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6823 /* The methods above are in versions 1 and 2 of the sqlite_module object. 6824 ** Those below are for version 3 and greater. */ 6825 int (*xShadowName)(const char*); 6826}; 6827 6828/* 6829** CAPI3REF: Virtual Table Indexing Information 6830** KEYWORDS: sqlite3_index_info 6831** 6832** The sqlite3_index_info structure and its substructures is used as part 6833** of the [virtual table] interface to 6834** pass information into and receive the reply from the [xBestIndex] 6835** method of a [virtual table module]. The fields under **Inputs** are the 6836** inputs to xBestIndex and are read-only. xBestIndex inserts its 6837** results into the **Outputs** fields. 6838** 6839** ^(The aConstraint[] array records WHERE clause constraints of the form: 6840** 6841** <blockquote>column OP expr</blockquote> 6842** 6843** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6844** stored in aConstraint[].op using one of the 6845** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6846** ^(The index of the column is stored in 6847** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6848** expr on the right-hand side can be evaluated (and thus the constraint 6849** is usable) and false if it cannot.)^ 6850** 6851** ^The optimizer automatically inverts terms of the form "expr OP column" 6852** and makes other simplifications to the WHERE clause in an attempt to 6853** get as many WHERE clause terms into the form shown above as possible. 6854** ^The aConstraint[] array only reports WHERE clause terms that are 6855** relevant to the particular virtual table being queried. 6856** 6857** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6858** ^Each term of aOrderBy records a column of the ORDER BY clause. 6859** 6860** The colUsed field indicates which columns of the virtual table may be 6861** required by the current scan. Virtual table columns are numbered from 6862** zero in the order in which they appear within the CREATE TABLE statement 6863** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6864** the corresponding bit is set within the colUsed mask if the column may be 6865** required by SQLite. If the table has at least 64 columns and any column 6866** to the right of the first 63 is required, then bit 63 of colUsed is also 6867** set. In other words, column iCol may be required if the expression 6868** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6869** non-zero. 6870** 6871** The [xBestIndex] method must fill aConstraintUsage[] with information 6872** about what parameters to pass to xFilter. ^If argvIndex>0 then 6873** the right-hand side of the corresponding aConstraint[] is evaluated 6874** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6875** is true, then the constraint is assumed to be fully handled by the 6876** virtual table and might not be checked again by the byte code.)^ ^(The 6877** aConstraintUsage[].omit flag is an optimization hint. When the omit flag 6878** is left in its default setting of false, the constraint will always be 6879** checked separately in byte code. If the omit flag is change to true, then 6880** the constraint may or may not be checked in byte code. In other words, 6881** when the omit flag is true there is no guarantee that the constraint will 6882** not be checked again using byte code.)^ 6883** 6884** ^The idxNum and idxPtr values are recorded and passed into the 6885** [xFilter] method. 6886** ^[sqlite3_free()] is used to free idxPtr if and only if 6887** needToFreeIdxPtr is true. 6888** 6889** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6890** the correct order to satisfy the ORDER BY clause so that no separate 6891** sorting step is required. 6892** 6893** ^The estimatedCost value is an estimate of the cost of a particular 6894** strategy. A cost of N indicates that the cost of the strategy is similar 6895** to a linear scan of an SQLite table with N rows. A cost of log(N) 6896** indicates that the expense of the operation is similar to that of a 6897** binary search on a unique indexed field of an SQLite table with N rows. 6898** 6899** ^The estimatedRows value is an estimate of the number of rows that 6900** will be returned by the strategy. 6901** 6902** The xBestIndex method may optionally populate the idxFlags field with a 6903** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6904** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6905** assumes that the strategy may visit at most one row. 6906** 6907** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6908** SQLite also assumes that if a call to the xUpdate() method is made as 6909** part of the same statement to delete or update a virtual table row and the 6910** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6911** any database changes. In other words, if the xUpdate() returns 6912** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6913** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6914** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6915** the xUpdate method are automatically rolled back by SQLite. 6916** 6917** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6918** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6919** If a virtual table extension is 6920** used with an SQLite version earlier than 3.8.2, the results of attempting 6921** to read or write the estimatedRows field are undefined (but are likely 6922** to include crashing the application). The estimatedRows field should 6923** therefore only be used if [sqlite3_libversion_number()] returns a 6924** value greater than or equal to 3008002. Similarly, the idxFlags field 6925** was added for [version 3.9.0] ([dateof:3.9.0]). 6926** It may therefore only be used if 6927** sqlite3_libversion_number() returns a value greater than or equal to 6928** 3009000. 6929*/ 6930struct sqlite3_index_info { 6931 /* Inputs */ 6932 int nConstraint; /* Number of entries in aConstraint */ 6933 struct sqlite3_index_constraint { 6934 int iColumn; /* Column constrained. -1 for ROWID */ 6935 unsigned char op; /* Constraint operator */ 6936 unsigned char usable; /* True if this constraint is usable */ 6937 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6938 } *aConstraint; /* Table of WHERE clause constraints */ 6939 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6940 struct sqlite3_index_orderby { 6941 int iColumn; /* Column number */ 6942 unsigned char desc; /* True for DESC. False for ASC. */ 6943 } *aOrderBy; /* The ORDER BY clause */ 6944 /* Outputs */ 6945 struct sqlite3_index_constraint_usage { 6946 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6947 unsigned char omit; /* Do not code a test for this constraint */ 6948 } *aConstraintUsage; 6949 int idxNum; /* Number used to identify the index */ 6950 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6951 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6952 int orderByConsumed; /* True if output is already ordered */ 6953 double estimatedCost; /* Estimated cost of using this index */ 6954 /* Fields below are only available in SQLite 3.8.2 and later */ 6955 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6956 /* Fields below are only available in SQLite 3.9.0 and later */ 6957 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6958 /* Fields below are only available in SQLite 3.10.0 and later */ 6959 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6960}; 6961 6962/* 6963** CAPI3REF: Virtual Table Scan Flags 6964** 6965** Virtual table implementations are allowed to set the 6966** [sqlite3_index_info].idxFlags field to some combination of 6967** these bits. 6968*/ 6969#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6970 6971/* 6972** CAPI3REF: Virtual Table Constraint Operator Codes 6973** 6974** These macros define the allowed values for the 6975** [sqlite3_index_info].aConstraint[].op field. Each value represents 6976** an operator that is part of a constraint term in the wHERE clause of 6977** a query that uses a [virtual table]. 6978*/ 6979#define SQLITE_INDEX_CONSTRAINT_EQ 2 6980#define SQLITE_INDEX_CONSTRAINT_GT 4 6981#define SQLITE_INDEX_CONSTRAINT_LE 8 6982#define SQLITE_INDEX_CONSTRAINT_LT 16 6983#define SQLITE_INDEX_CONSTRAINT_GE 32 6984#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6985#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6986#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6987#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6988#define SQLITE_INDEX_CONSTRAINT_NE 68 6989#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6990#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6991#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6992#define SQLITE_INDEX_CONSTRAINT_IS 72 6993#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150 6994 6995/* 6996** CAPI3REF: Register A Virtual Table Implementation 6997** METHOD: sqlite3 6998** 6999** ^These routines are used to register a new [virtual table module] name. 7000** ^Module names must be registered before 7001** creating a new [virtual table] using the module and before using a 7002** preexisting [virtual table] for the module. 7003** 7004** ^The module name is registered on the [database connection] specified 7005** by the first parameter. ^The name of the module is given by the 7006** second parameter. ^The third parameter is a pointer to 7007** the implementation of the [virtual table module]. ^The fourth 7008** parameter is an arbitrary client data pointer that is passed through 7009** into the [xCreate] and [xConnect] methods of the virtual table module 7010** when a new virtual table is be being created or reinitialized. 7011** 7012** ^The sqlite3_create_module_v2() interface has a fifth parameter which 7013** is a pointer to a destructor for the pClientData. ^SQLite will 7014** invoke the destructor function (if it is not NULL) when SQLite 7015** no longer needs the pClientData pointer. ^The destructor will also 7016** be invoked if the call to sqlite3_create_module_v2() fails. 7017** ^The sqlite3_create_module() 7018** interface is equivalent to sqlite3_create_module_v2() with a NULL 7019** destructor. 7020** 7021** ^If the third parameter (the pointer to the sqlite3_module object) is 7022** NULL then no new module is create and any existing modules with the 7023** same name are dropped. 7024** 7025** See also: [sqlite3_drop_modules()] 7026*/ 7027int sqlite3_create_module( 7028 sqlite3 *db, /* SQLite connection to register module with */ 7029 const char *zName, /* Name of the module */ 7030 const sqlite3_module *p, /* Methods for the module */ 7031 void *pClientData /* Client data for xCreate/xConnect */ 7032); 7033int sqlite3_create_module_v2( 7034 sqlite3 *db, /* SQLite connection to register module with */ 7035 const char *zName, /* Name of the module */ 7036 const sqlite3_module *p, /* Methods for the module */ 7037 void *pClientData, /* Client data for xCreate/xConnect */ 7038 void(*xDestroy)(void*) /* Module destructor function */ 7039); 7040 7041/* 7042** CAPI3REF: Remove Unnecessary Virtual Table Implementations 7043** METHOD: sqlite3 7044** 7045** ^The sqlite3_drop_modules(D,L) interface removes all virtual 7046** table modules from database connection D except those named on list L. 7047** The L parameter must be either NULL or a pointer to an array of pointers 7048** to strings where the array is terminated by a single NULL pointer. 7049** ^If the L parameter is NULL, then all virtual table modules are removed. 7050** 7051** See also: [sqlite3_create_module()] 7052*/ 7053int sqlite3_drop_modules( 7054 sqlite3 *db, /* Remove modules from this connection */ 7055 const char **azKeep /* Except, do not remove the ones named here */ 7056); 7057 7058/* 7059** CAPI3REF: Virtual Table Instance Object 7060** KEYWORDS: sqlite3_vtab 7061** 7062** Every [virtual table module] implementation uses a subclass 7063** of this object to describe a particular instance 7064** of the [virtual table]. Each subclass will 7065** be tailored to the specific needs of the module implementation. 7066** The purpose of this superclass is to define certain fields that are 7067** common to all module implementations. 7068** 7069** ^Virtual tables methods can set an error message by assigning a 7070** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 7071** take care that any prior string is freed by a call to [sqlite3_free()] 7072** prior to assigning a new string to zErrMsg. ^After the error message 7073** is delivered up to the client application, the string will be automatically 7074** freed by sqlite3_free() and the zErrMsg field will be zeroed. 7075*/ 7076struct sqlite3_vtab { 7077 const sqlite3_module *pModule; /* The module for this virtual table */ 7078 int nRef; /* Number of open cursors */ 7079 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 7080 /* Virtual table implementations will typically add additional fields */ 7081}; 7082 7083/* 7084** CAPI3REF: Virtual Table Cursor Object 7085** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 7086** 7087** Every [virtual table module] implementation uses a subclass of the 7088** following structure to describe cursors that point into the 7089** [virtual table] and are used 7090** to loop through the virtual table. Cursors are created using the 7091** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 7092** by the [sqlite3_module.xClose | xClose] method. Cursors are used 7093** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 7094** of the module. Each module implementation will define 7095** the content of a cursor structure to suit its own needs. 7096** 7097** This superclass exists in order to define fields of the cursor that 7098** are common to all implementations. 7099*/ 7100struct sqlite3_vtab_cursor { 7101 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 7102 /* Virtual table implementations will typically add additional fields */ 7103}; 7104 7105/* 7106** CAPI3REF: Declare The Schema Of A Virtual Table 7107** 7108** ^The [xCreate] and [xConnect] methods of a 7109** [virtual table module] call this interface 7110** to declare the format (the names and datatypes of the columns) of 7111** the virtual tables they implement. 7112*/ 7113int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 7114 7115/* 7116** CAPI3REF: Overload A Function For A Virtual Table 7117** METHOD: sqlite3 7118** 7119** ^(Virtual tables can provide alternative implementations of functions 7120** using the [xFindFunction] method of the [virtual table module]. 7121** But global versions of those functions 7122** must exist in order to be overloaded.)^ 7123** 7124** ^(This API makes sure a global version of a function with a particular 7125** name and number of parameters exists. If no such function exists 7126** before this API is called, a new function is created.)^ ^The implementation 7127** of the new function always causes an exception to be thrown. So 7128** the new function is not good for anything by itself. Its only 7129** purpose is to be a placeholder function that can be overloaded 7130** by a [virtual table]. 7131*/ 7132int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 7133 7134/* 7135** The interface to the virtual-table mechanism defined above (back up 7136** to a comment remarkably similar to this one) is currently considered 7137** to be experimental. The interface might change in incompatible ways. 7138** If this is a problem for you, do not use the interface at this time. 7139** 7140** When the virtual-table mechanism stabilizes, we will declare the 7141** interface fixed, support it indefinitely, and remove this comment. 7142*/ 7143 7144/* 7145** CAPI3REF: A Handle To An Open BLOB 7146** KEYWORDS: {BLOB handle} {BLOB handles} 7147** 7148** An instance of this object represents an open BLOB on which 7149** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 7150** ^Objects of this type are created by [sqlite3_blob_open()] 7151** and destroyed by [sqlite3_blob_close()]. 7152** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 7153** can be used to read or write small subsections of the BLOB. 7154** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 7155*/ 7156typedef struct sqlite3_blob sqlite3_blob; 7157 7158/* 7159** CAPI3REF: Open A BLOB For Incremental I/O 7160** METHOD: sqlite3 7161** CONSTRUCTOR: sqlite3_blob 7162** 7163** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 7164** in row iRow, column zColumn, table zTable in database zDb; 7165** in other words, the same BLOB that would be selected by: 7166** 7167** <pre> 7168** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 7169** </pre>)^ 7170** 7171** ^(Parameter zDb is not the filename that contains the database, but 7172** rather the symbolic name of the database. For attached databases, this is 7173** the name that appears after the AS keyword in the [ATTACH] statement. 7174** For the main database file, the database name is "main". For TEMP 7175** tables, the database name is "temp".)^ 7176** 7177** ^If the flags parameter is non-zero, then the BLOB is opened for read 7178** and write access. ^If the flags parameter is zero, the BLOB is opened for 7179** read-only access. 7180** 7181** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 7182** in *ppBlob. Otherwise an [error code] is returned and, unless the error 7183** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 7184** the API is not misused, it is always safe to call [sqlite3_blob_close()] 7185** on *ppBlob after this function it returns. 7186** 7187** This function fails with SQLITE_ERROR if any of the following are true: 7188** <ul> 7189** <li> ^(Database zDb does not exist)^, 7190** <li> ^(Table zTable does not exist within database zDb)^, 7191** <li> ^(Table zTable is a WITHOUT ROWID table)^, 7192** <li> ^(Column zColumn does not exist)^, 7193** <li> ^(Row iRow is not present in the table)^, 7194** <li> ^(The specified column of row iRow contains a value that is not 7195** a TEXT or BLOB value)^, 7196** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 7197** constraint and the blob is being opened for read/write access)^, 7198** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 7199** column zColumn is part of a [child key] definition and the blob is 7200** being opened for read/write access)^. 7201** </ul> 7202** 7203** ^Unless it returns SQLITE_MISUSE, this function sets the 7204** [database connection] error code and message accessible via 7205** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7206** 7207** A BLOB referenced by sqlite3_blob_open() may be read using the 7208** [sqlite3_blob_read()] interface and modified by using 7209** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 7210** different row of the same table using the [sqlite3_blob_reopen()] 7211** interface. However, the column, table, or database of a [BLOB handle] 7212** cannot be changed after the [BLOB handle] is opened. 7213** 7214** ^(If the row that a BLOB handle points to is modified by an 7215** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 7216** then the BLOB handle is marked as "expired". 7217** This is true if any column of the row is changed, even a column 7218** other than the one the BLOB handle is open on.)^ 7219** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 7220** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 7221** ^(Changes written into a BLOB prior to the BLOB expiring are not 7222** rolled back by the expiration of the BLOB. Such changes will eventually 7223** commit if the transaction continues to completion.)^ 7224** 7225** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 7226** the opened blob. ^The size of a blob may not be changed by this 7227** interface. Use the [UPDATE] SQL command to change the size of a 7228** blob. 7229** 7230** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 7231** and the built-in [zeroblob] SQL function may be used to create a 7232** zero-filled blob to read or write using the incremental-blob interface. 7233** 7234** To avoid a resource leak, every open [BLOB handle] should eventually 7235** be released by a call to [sqlite3_blob_close()]. 7236** 7237** See also: [sqlite3_blob_close()], 7238** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 7239** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 7240*/ 7241int sqlite3_blob_open( 7242 sqlite3*, 7243 const char *zDb, 7244 const char *zTable, 7245 const char *zColumn, 7246 sqlite3_int64 iRow, 7247 int flags, 7248 sqlite3_blob **ppBlob 7249); 7250 7251/* 7252** CAPI3REF: Move a BLOB Handle to a New Row 7253** METHOD: sqlite3_blob 7254** 7255** ^This function is used to move an existing [BLOB handle] so that it points 7256** to a different row of the same database table. ^The new row is identified 7257** by the rowid value passed as the second argument. Only the row can be 7258** changed. ^The database, table and column on which the blob handle is open 7259** remain the same. Moving an existing [BLOB handle] to a new row is 7260** faster than closing the existing handle and opening a new one. 7261** 7262** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 7263** it must exist and there must be either a blob or text value stored in 7264** the nominated column.)^ ^If the new row is not present in the table, or if 7265** it does not contain a blob or text value, or if another error occurs, an 7266** SQLite error code is returned and the blob handle is considered aborted. 7267** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 7268** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 7269** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 7270** always returns zero. 7271** 7272** ^This function sets the database handle error code and message. 7273*/ 7274int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 7275 7276/* 7277** CAPI3REF: Close A BLOB Handle 7278** DESTRUCTOR: sqlite3_blob 7279** 7280** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 7281** unconditionally. Even if this routine returns an error code, the 7282** handle is still closed.)^ 7283** 7284** ^If the blob handle being closed was opened for read-write access, and if 7285** the database is in auto-commit mode and there are no other open read-write 7286** blob handles or active write statements, the current transaction is 7287** committed. ^If an error occurs while committing the transaction, an error 7288** code is returned and the transaction rolled back. 7289** 7290** Calling this function with an argument that is not a NULL pointer or an 7291** open blob handle results in undefined behaviour. ^Calling this routine 7292** with a null pointer (such as would be returned by a failed call to 7293** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 7294** is passed a valid open blob handle, the values returned by the 7295** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 7296*/ 7297int sqlite3_blob_close(sqlite3_blob *); 7298 7299/* 7300** CAPI3REF: Return The Size Of An Open BLOB 7301** METHOD: sqlite3_blob 7302** 7303** ^Returns the size in bytes of the BLOB accessible via the 7304** successfully opened [BLOB handle] in its only argument. ^The 7305** incremental blob I/O routines can only read or overwriting existing 7306** blob content; they cannot change the size of a blob. 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*/ 7313int sqlite3_blob_bytes(sqlite3_blob *); 7314 7315/* 7316** CAPI3REF: Read Data From A BLOB Incrementally 7317** METHOD: sqlite3_blob 7318** 7319** ^(This function is used to read data from an open [BLOB handle] into a 7320** caller-supplied buffer. N bytes of data are copied into buffer Z 7321** from the open BLOB, starting at offset iOffset.)^ 7322** 7323** ^If offset iOffset is less than N bytes from the end of the BLOB, 7324** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 7325** less than zero, [SQLITE_ERROR] is returned and no data is read. 7326** ^The size of the blob (and hence the maximum value of N+iOffset) 7327** can be determined using the [sqlite3_blob_bytes()] interface. 7328** 7329** ^An attempt to read from an expired [BLOB handle] fails with an 7330** error code of [SQLITE_ABORT]. 7331** 7332** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 7333** Otherwise, an [error code] or an [extended error code] is returned.)^ 7334** 7335** This routine only works on a [BLOB handle] which has been created 7336** by a prior successful call to [sqlite3_blob_open()] and which has not 7337** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7338** to this routine results in undefined and probably undesirable behavior. 7339** 7340** See also: [sqlite3_blob_write()]. 7341*/ 7342int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 7343 7344/* 7345** CAPI3REF: Write Data Into A BLOB Incrementally 7346** METHOD: sqlite3_blob 7347** 7348** ^(This function is used to write data into an open [BLOB handle] from a 7349** caller-supplied buffer. N bytes of data are copied from the buffer Z 7350** into the open BLOB, starting at offset iOffset.)^ 7351** 7352** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 7353** Otherwise, an [error code] or an [extended error code] is returned.)^ 7354** ^Unless SQLITE_MISUSE is returned, this function sets the 7355** [database connection] error code and message accessible via 7356** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7357** 7358** ^If the [BLOB handle] passed as the first argument was not opened for 7359** writing (the flags parameter to [sqlite3_blob_open()] was zero), 7360** this function returns [SQLITE_READONLY]. 7361** 7362** This function may only modify the contents of the BLOB; it is 7363** not possible to increase the size of a BLOB using this API. 7364** ^If offset iOffset is less than N bytes from the end of the BLOB, 7365** [SQLITE_ERROR] is returned and no data is written. The size of the 7366** BLOB (and hence the maximum value of N+iOffset) can be determined 7367** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 7368** than zero [SQLITE_ERROR] is returned and no data is written. 7369** 7370** ^An attempt to write to an expired [BLOB handle] fails with an 7371** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 7372** before the [BLOB handle] expired are not rolled back by the 7373** expiration of the handle, though of course those changes might 7374** have been overwritten by the statement that expired the BLOB handle 7375** or by other independent statements. 7376** 7377** This routine only works on a [BLOB handle] which has been created 7378** by a prior successful call to [sqlite3_blob_open()] and which has not 7379** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7380** to this routine results in undefined and probably undesirable behavior. 7381** 7382** See also: [sqlite3_blob_read()]. 7383*/ 7384int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 7385 7386/* 7387** CAPI3REF: Virtual File System Objects 7388** 7389** A virtual filesystem (VFS) is an [sqlite3_vfs] object 7390** that SQLite uses to interact 7391** with the underlying operating system. Most SQLite builds come with a 7392** single default VFS that is appropriate for the host computer. 7393** New VFSes can be registered and existing VFSes can be unregistered. 7394** The following interfaces are provided. 7395** 7396** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 7397** ^Names are case sensitive. 7398** ^Names are zero-terminated UTF-8 strings. 7399** ^If there is no match, a NULL pointer is returned. 7400** ^If zVfsName is NULL then the default VFS is returned. 7401** 7402** ^New VFSes are registered with sqlite3_vfs_register(). 7403** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 7404** ^The same VFS can be registered multiple times without injury. 7405** ^To make an existing VFS into the default VFS, register it again 7406** with the makeDflt flag set. If two different VFSes with the 7407** same name are registered, the behavior is undefined. If a 7408** VFS is registered with a name that is NULL or an empty string, 7409** then the behavior is undefined. 7410** 7411** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 7412** ^(If the default VFS is unregistered, another VFS is chosen as 7413** the default. The choice for the new VFS is arbitrary.)^ 7414*/ 7415sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 7416int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 7417int sqlite3_vfs_unregister(sqlite3_vfs*); 7418 7419/* 7420** CAPI3REF: Mutexes 7421** 7422** The SQLite core uses these routines for thread 7423** synchronization. Though they are intended for internal 7424** use by SQLite, code that links against SQLite is 7425** permitted to use any of these routines. 7426** 7427** The SQLite source code contains multiple implementations 7428** of these mutex routines. An appropriate implementation 7429** is selected automatically at compile-time. The following 7430** implementations are available in the SQLite core: 7431** 7432** <ul> 7433** <li> SQLITE_MUTEX_PTHREADS 7434** <li> SQLITE_MUTEX_W32 7435** <li> SQLITE_MUTEX_NOOP 7436** </ul> 7437** 7438** The SQLITE_MUTEX_NOOP implementation is a set of routines 7439** that does no real locking and is appropriate for use in 7440** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 7441** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 7442** and Windows. 7443** 7444** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 7445** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 7446** implementation is included with the library. In this case the 7447** application must supply a custom mutex implementation using the 7448** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 7449** before calling sqlite3_initialize() or any other public sqlite3_ 7450** function that calls sqlite3_initialize(). 7451** 7452** ^The sqlite3_mutex_alloc() routine allocates a new 7453** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 7454** routine returns NULL if it is unable to allocate the requested 7455** mutex. The argument to sqlite3_mutex_alloc() must one of these 7456** integer constants: 7457** 7458** <ul> 7459** <li> SQLITE_MUTEX_FAST 7460** <li> SQLITE_MUTEX_RECURSIVE 7461** <li> SQLITE_MUTEX_STATIC_MAIN 7462** <li> SQLITE_MUTEX_STATIC_MEM 7463** <li> SQLITE_MUTEX_STATIC_OPEN 7464** <li> SQLITE_MUTEX_STATIC_PRNG 7465** <li> SQLITE_MUTEX_STATIC_LRU 7466** <li> SQLITE_MUTEX_STATIC_PMEM 7467** <li> SQLITE_MUTEX_STATIC_APP1 7468** <li> SQLITE_MUTEX_STATIC_APP2 7469** <li> SQLITE_MUTEX_STATIC_APP3 7470** <li> SQLITE_MUTEX_STATIC_VFS1 7471** <li> SQLITE_MUTEX_STATIC_VFS2 7472** <li> SQLITE_MUTEX_STATIC_VFS3 7473** </ul> 7474** 7475** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 7476** cause sqlite3_mutex_alloc() to create 7477** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 7478** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 7479** The mutex implementation does not need to make a distinction 7480** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 7481** not want to. SQLite will only request a recursive mutex in 7482** cases where it really needs one. If a faster non-recursive mutex 7483** implementation is available on the host platform, the mutex subsystem 7484** might return such a mutex in response to SQLITE_MUTEX_FAST. 7485** 7486** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 7487** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 7488** a pointer to a static preexisting mutex. ^Nine static mutexes are 7489** used by the current version of SQLite. Future versions of SQLite 7490** may add additional static mutexes. Static mutexes are for internal 7491** use by SQLite only. Applications that use SQLite mutexes should 7492** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 7493** SQLITE_MUTEX_RECURSIVE. 7494** 7495** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 7496** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 7497** returns a different mutex on every call. ^For the static 7498** mutex types, the same mutex is returned on every call that has 7499** the same type number. 7500** 7501** ^The sqlite3_mutex_free() routine deallocates a previously 7502** allocated dynamic mutex. Attempting to deallocate a static 7503** mutex results in undefined behavior. 7504** 7505** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 7506** to enter a mutex. ^If another thread is already within the mutex, 7507** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 7508** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 7509** upon successful entry. ^(Mutexes created using 7510** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 7511** In such cases, the 7512** mutex must be exited an equal number of times before another thread 7513** can enter.)^ If the same thread tries to enter any mutex other 7514** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 7515** 7516** ^(Some systems (for example, Windows 95) do not support the operation 7517** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 7518** will always return SQLITE_BUSY. The SQLite core only ever uses 7519** sqlite3_mutex_try() as an optimization so this is acceptable 7520** behavior.)^ 7521** 7522** ^The sqlite3_mutex_leave() routine exits a mutex that was 7523** previously entered by the same thread. The behavior 7524** is undefined if the mutex is not currently entered by the 7525** calling thread or is not currently allocated. 7526** 7527** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 7528** sqlite3_mutex_leave() is a NULL pointer, then all three routines 7529** behave as no-ops. 7530** 7531** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 7532*/ 7533sqlite3_mutex *sqlite3_mutex_alloc(int); 7534void sqlite3_mutex_free(sqlite3_mutex*); 7535void sqlite3_mutex_enter(sqlite3_mutex*); 7536int sqlite3_mutex_try(sqlite3_mutex*); 7537void sqlite3_mutex_leave(sqlite3_mutex*); 7538 7539/* 7540** CAPI3REF: Mutex Methods Object 7541** 7542** An instance of this structure defines the low-level routines 7543** used to allocate and use mutexes. 7544** 7545** Usually, the default mutex implementations provided by SQLite are 7546** sufficient, however the application has the option of substituting a custom 7547** implementation for specialized deployments or systems for which SQLite 7548** does not provide a suitable implementation. In this case, the application 7549** creates and populates an instance of this structure to pass 7550** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 7551** Additionally, an instance of this structure can be used as an 7552** output variable when querying the system for the current mutex 7553** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 7554** 7555** ^The xMutexInit method defined by this structure is invoked as 7556** part of system initialization by the sqlite3_initialize() function. 7557** ^The xMutexInit routine is called by SQLite exactly once for each 7558** effective call to [sqlite3_initialize()]. 7559** 7560** ^The xMutexEnd method defined by this structure is invoked as 7561** part of system shutdown by the sqlite3_shutdown() function. The 7562** implementation of this method is expected to release all outstanding 7563** resources obtained by the mutex methods implementation, especially 7564** those obtained by the xMutexInit method. ^The xMutexEnd() 7565** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 7566** 7567** ^(The remaining seven methods defined by this structure (xMutexAlloc, 7568** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 7569** xMutexNotheld) implement the following interfaces (respectively): 7570** 7571** <ul> 7572** <li> [sqlite3_mutex_alloc()] </li> 7573** <li> [sqlite3_mutex_free()] </li> 7574** <li> [sqlite3_mutex_enter()] </li> 7575** <li> [sqlite3_mutex_try()] </li> 7576** <li> [sqlite3_mutex_leave()] </li> 7577** <li> [sqlite3_mutex_held()] </li> 7578** <li> [sqlite3_mutex_notheld()] </li> 7579** </ul>)^ 7580** 7581** The only difference is that the public sqlite3_XXX functions enumerated 7582** above silently ignore any invocations that pass a NULL pointer instead 7583** of a valid mutex handle. The implementations of the methods defined 7584** by this structure are not required to handle this case. The results 7585** of passing a NULL pointer instead of a valid mutex handle are undefined 7586** (i.e. it is acceptable to provide an implementation that segfaults if 7587** it is passed a NULL pointer). 7588** 7589** The xMutexInit() method must be threadsafe. It must be harmless to 7590** invoke xMutexInit() multiple times within the same process and without 7591** intervening calls to xMutexEnd(). Second and subsequent calls to 7592** xMutexInit() must be no-ops. 7593** 7594** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 7595** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 7596** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 7597** memory allocation for a fast or recursive mutex. 7598** 7599** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 7600** called, but only if the prior call to xMutexInit returned SQLITE_OK. 7601** If xMutexInit fails in any way, it is expected to clean up after itself 7602** prior to returning. 7603*/ 7604typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 7605struct sqlite3_mutex_methods { 7606 int (*xMutexInit)(void); 7607 int (*xMutexEnd)(void); 7608 sqlite3_mutex *(*xMutexAlloc)(int); 7609 void (*xMutexFree)(sqlite3_mutex *); 7610 void (*xMutexEnter)(sqlite3_mutex *); 7611 int (*xMutexTry)(sqlite3_mutex *); 7612 void (*xMutexLeave)(sqlite3_mutex *); 7613 int (*xMutexHeld)(sqlite3_mutex *); 7614 int (*xMutexNotheld)(sqlite3_mutex *); 7615}; 7616 7617/* 7618** CAPI3REF: Mutex Verification Routines 7619** 7620** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 7621** are intended for use inside assert() statements. The SQLite core 7622** never uses these routines except inside an assert() and applications 7623** are advised to follow the lead of the core. The SQLite core only 7624** provides implementations for these routines when it is compiled 7625** with the SQLITE_DEBUG flag. External mutex implementations 7626** are only required to provide these routines if SQLITE_DEBUG is 7627** defined and if NDEBUG is not defined. 7628** 7629** These routines should return true if the mutex in their argument 7630** is held or not held, respectively, by the calling thread. 7631** 7632** The implementation is not required to provide versions of these 7633** routines that actually work. If the implementation does not provide working 7634** versions of these routines, it should at least provide stubs that always 7635** return true so that one does not get spurious assertion failures. 7636** 7637** If the argument to sqlite3_mutex_held() is a NULL pointer then 7638** the routine should return 1. This seems counter-intuitive since 7639** clearly the mutex cannot be held if it does not exist. But 7640** the reason the mutex does not exist is because the build is not 7641** using mutexes. And we do not want the assert() containing the 7642** call to sqlite3_mutex_held() to fail, so a non-zero return is 7643** the appropriate thing to do. The sqlite3_mutex_notheld() 7644** interface should also return 1 when given a NULL pointer. 7645*/ 7646#ifndef NDEBUG 7647int sqlite3_mutex_held(sqlite3_mutex*); 7648int sqlite3_mutex_notheld(sqlite3_mutex*); 7649#endif 7650 7651/* 7652** CAPI3REF: Mutex Types 7653** 7654** The [sqlite3_mutex_alloc()] interface takes a single argument 7655** which is one of these integer constants. 7656** 7657** The set of static mutexes may change from one SQLite release to the 7658** next. Applications that override the built-in mutex logic must be 7659** prepared to accommodate additional static mutexes. 7660*/ 7661#define SQLITE_MUTEX_FAST 0 7662#define SQLITE_MUTEX_RECURSIVE 1 7663#define SQLITE_MUTEX_STATIC_MAIN 2 7664#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 7665#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 7666#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 7667#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 7668#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 7669#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 7670#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 7671#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 7672#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 7673#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 7674#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 7675#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 7676#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 7677 7678/* Legacy compatibility: */ 7679#define SQLITE_MUTEX_STATIC_MASTER 2 7680 7681 7682/* 7683** CAPI3REF: Retrieve the mutex for a database connection 7684** METHOD: sqlite3 7685** 7686** ^This interface returns a pointer the [sqlite3_mutex] object that 7687** serializes access to the [database connection] given in the argument 7688** when the [threading mode] is Serialized. 7689** ^If the [threading mode] is Single-thread or Multi-thread then this 7690** routine returns a NULL pointer. 7691*/ 7692sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 7693 7694/* 7695** CAPI3REF: Low-Level Control Of Database Files 7696** METHOD: sqlite3 7697** KEYWORDS: {file control} 7698** 7699** ^The [sqlite3_file_control()] interface makes a direct call to the 7700** xFileControl method for the [sqlite3_io_methods] object associated 7701** with a particular database identified by the second argument. ^The 7702** name of the database is "main" for the main database or "temp" for the 7703** TEMP database, or the name that appears after the AS keyword for 7704** databases that are added using the [ATTACH] SQL command. 7705** ^A NULL pointer can be used in place of "main" to refer to the 7706** main database file. 7707** ^The third and fourth parameters to this routine 7708** are passed directly through to the second and third parameters of 7709** the xFileControl method. ^The return value of the xFileControl 7710** method becomes the return value of this routine. 7711** 7712** A few opcodes for [sqlite3_file_control()] are handled directly 7713** by the SQLite core and never invoke the 7714** sqlite3_io_methods.xFileControl method. 7715** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 7716** a pointer to the underlying [sqlite3_file] object to be written into 7717** the space pointed to by the 4th parameter. The 7718** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns 7719** the [sqlite3_file] object associated with the journal file instead of 7720** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns 7721** a pointer to the underlying [sqlite3_vfs] object for the file. 7722** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter 7723** from the pager. 7724** 7725** ^If the second parameter (zDbName) does not match the name of any 7726** open database file, then SQLITE_ERROR is returned. ^This error 7727** code is not remembered and will not be recalled by [sqlite3_errcode()] 7728** or [sqlite3_errmsg()]. The underlying xFileControl method might 7729** also return SQLITE_ERROR. There is no way to distinguish between 7730** an incorrect zDbName and an SQLITE_ERROR return from the underlying 7731** xFileControl method. 7732** 7733** See also: [file control opcodes] 7734*/ 7735int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 7736 7737/* 7738** CAPI3REF: Testing Interface 7739** 7740** ^The sqlite3_test_control() interface is used to read out internal 7741** state of SQLite and to inject faults into SQLite for testing 7742** purposes. ^The first parameter is an operation code that determines 7743** the number, meaning, and operation of all subsequent parameters. 7744** 7745** This interface is not for use by applications. It exists solely 7746** for verifying the correct operation of the SQLite library. Depending 7747** on how the SQLite library is compiled, this interface might not exist. 7748** 7749** The details of the operation codes, their meanings, the parameters 7750** they take, and what they do are all subject to change without notice. 7751** Unlike most of the SQLite API, this function is not guaranteed to 7752** operate consistently from one release to the next. 7753*/ 7754int sqlite3_test_control(int op, ...); 7755 7756/* 7757** CAPI3REF: Testing Interface Operation Codes 7758** 7759** These constants are the valid operation code parameters used 7760** as the first argument to [sqlite3_test_control()]. 7761** 7762** These parameters and their meanings are subject to change 7763** without notice. These values are for testing purposes only. 7764** Applications should not use any of these parameters or the 7765** [sqlite3_test_control()] interface. 7766*/ 7767#define SQLITE_TESTCTRL_FIRST 5 7768#define SQLITE_TESTCTRL_PRNG_SAVE 5 7769#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7770#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */ 7771#define SQLITE_TESTCTRL_BITVEC_TEST 8 7772#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7773#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7774#define SQLITE_TESTCTRL_PENDING_BYTE 11 7775#define SQLITE_TESTCTRL_ASSERT 12 7776#define SQLITE_TESTCTRL_ALWAYS 13 7777#define SQLITE_TESTCTRL_RESERVE 14 /* NOT USED */ 7778#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7779#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */ 7780#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7781#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17 7782#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7783#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7784#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7785#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7786#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7787#define SQLITE_TESTCTRL_BYTEORDER 22 7788#define SQLITE_TESTCTRL_ISINIT 23 7789#define SQLITE_TESTCTRL_SORTER_MMAP 24 7790#define SQLITE_TESTCTRL_IMPOSTER 25 7791#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7792#define SQLITE_TESTCTRL_RESULT_INTREAL 27 7793#define SQLITE_TESTCTRL_PRNG_SEED 28 7794#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29 7795#define SQLITE_TESTCTRL_SEEK_COUNT 30 7796#define SQLITE_TESTCTRL_TRACEFLAGS 31 7797#define SQLITE_TESTCTRL_LAST 31 /* Largest TESTCTRL */ 7798 7799/* 7800** CAPI3REF: SQL Keyword Checking 7801** 7802** These routines provide access to the set of SQL language keywords 7803** recognized by SQLite. Applications can uses these routines to determine 7804** whether or not a specific identifier needs to be escaped (for example, 7805** by enclosing in double-quotes) so as not to confuse the parser. 7806** 7807** The sqlite3_keyword_count() interface returns the number of distinct 7808** keywords understood by SQLite. 7809** 7810** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and 7811** makes *Z point to that keyword expressed as UTF8 and writes the number 7812** of bytes in the keyword into *L. The string that *Z points to is not 7813** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns 7814** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z 7815** or L are NULL or invalid pointers then calls to 7816** sqlite3_keyword_name(N,Z,L) result in undefined behavior. 7817** 7818** The sqlite3_keyword_check(Z,L) interface checks to see whether or not 7819** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero 7820** if it is and zero if not. 7821** 7822** The parser used by SQLite is forgiving. It is often possible to use 7823** a keyword as an identifier as long as such use does not result in a 7824** parsing ambiguity. For example, the statement 7825** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and 7826** creates a new table named "BEGIN" with three columns named 7827** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid 7828** using keywords as identifiers. Common techniques used to avoid keyword 7829** name collisions include: 7830** <ul> 7831** <li> Put all identifier names inside double-quotes. This is the official 7832** SQL way to escape identifier names. 7833** <li> Put identifier names inside [...]. This is not standard SQL, 7834** but it is what SQL Server does and so lots of programmers use this 7835** technique. 7836** <li> Begin every identifier with the letter "Z" as no SQL keywords start 7837** with "Z". 7838** <li> Include a digit somewhere in every identifier name. 7839** </ul> 7840** 7841** Note that the number of keywords understood by SQLite can depend on 7842** compile-time options. For example, "VACUUM" is not a keyword if 7843** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also, 7844** new keywords may be added to future releases of SQLite. 7845*/ 7846int sqlite3_keyword_count(void); 7847int sqlite3_keyword_name(int,const char**,int*); 7848int sqlite3_keyword_check(const char*,int); 7849 7850/* 7851** CAPI3REF: Dynamic String Object 7852** KEYWORDS: {dynamic string} 7853** 7854** An instance of the sqlite3_str object contains a dynamically-sized 7855** string under construction. 7856** 7857** The lifecycle of an sqlite3_str object is as follows: 7858** <ol> 7859** <li> ^The sqlite3_str object is created using [sqlite3_str_new()]. 7860** <li> ^Text is appended to the sqlite3_str object using various 7861** methods, such as [sqlite3_str_appendf()]. 7862** <li> ^The sqlite3_str object is destroyed and the string it created 7863** is returned using the [sqlite3_str_finish()] interface. 7864** </ol> 7865*/ 7866typedef struct sqlite3_str sqlite3_str; 7867 7868/* 7869** CAPI3REF: Create A New Dynamic String Object 7870** CONSTRUCTOR: sqlite3_str 7871** 7872** ^The [sqlite3_str_new(D)] interface allocates and initializes 7873** a new [sqlite3_str] object. To avoid memory leaks, the object returned by 7874** [sqlite3_str_new()] must be freed by a subsequent call to 7875** [sqlite3_str_finish(X)]. 7876** 7877** ^The [sqlite3_str_new(D)] interface always returns a pointer to a 7878** valid [sqlite3_str] object, though in the event of an out-of-memory 7879** error the returned object might be a special singleton that will 7880** silently reject new text, always return SQLITE_NOMEM from 7881** [sqlite3_str_errcode()], always return 0 for 7882** [sqlite3_str_length()], and always return NULL from 7883** [sqlite3_str_finish(X)]. It is always safe to use the value 7884** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter 7885** to any of the other [sqlite3_str] methods. 7886** 7887** The D parameter to [sqlite3_str_new(D)] may be NULL. If the 7888** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum 7889** length of the string contained in the [sqlite3_str] object will be 7890** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead 7891** of [SQLITE_MAX_LENGTH]. 7892*/ 7893sqlite3_str *sqlite3_str_new(sqlite3*); 7894 7895/* 7896** CAPI3REF: Finalize A Dynamic String 7897** DESTRUCTOR: sqlite3_str 7898** 7899** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X 7900** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()] 7901** that contains the constructed string. The calling application should 7902** pass the returned value to [sqlite3_free()] to avoid a memory leak. 7903** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any 7904** errors were encountered during construction of the string. ^The 7905** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the 7906** string in [sqlite3_str] object X is zero bytes long. 7907*/ 7908char *sqlite3_str_finish(sqlite3_str*); 7909 7910/* 7911** CAPI3REF: Add Content To A Dynamic String 7912** METHOD: sqlite3_str 7913** 7914** These interfaces add content to an sqlite3_str object previously obtained 7915** from [sqlite3_str_new()]. 7916** 7917** ^The [sqlite3_str_appendf(X,F,...)] and 7918** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf] 7919** functionality of SQLite to append formatted text onto the end of 7920** [sqlite3_str] object X. 7921** 7922** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S 7923** onto the end of the [sqlite3_str] object X. N must be non-negative. 7924** S must contain at least N non-zero bytes of content. To append a 7925** zero-terminated string in its entirety, use the [sqlite3_str_appendall()] 7926** method instead. 7927** 7928** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of 7929** zero-terminated string S onto the end of [sqlite3_str] object X. 7930** 7931** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the 7932** single-byte character C onto the end of [sqlite3_str] object X. 7933** ^This method can be used, for example, to add whitespace indentation. 7934** 7935** ^The [sqlite3_str_reset(X)] method resets the string under construction 7936** inside [sqlite3_str] object X back to zero bytes in length. 7937** 7938** These methods do not return a result code. ^If an error occurs, that fact 7939** is recorded in the [sqlite3_str] object and can be recovered by a 7940** subsequent call to [sqlite3_str_errcode(X)]. 7941*/ 7942void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...); 7943void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list); 7944void sqlite3_str_append(sqlite3_str*, const char *zIn, int N); 7945void sqlite3_str_appendall(sqlite3_str*, const char *zIn); 7946void sqlite3_str_appendchar(sqlite3_str*, int N, char C); 7947void sqlite3_str_reset(sqlite3_str*); 7948 7949/* 7950** CAPI3REF: Status Of A Dynamic String 7951** METHOD: sqlite3_str 7952** 7953** These interfaces return the current status of an [sqlite3_str] object. 7954** 7955** ^If any prior errors have occurred while constructing the dynamic string 7956** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return 7957** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns 7958** [SQLITE_NOMEM] following any out-of-memory error, or 7959** [SQLITE_TOOBIG] if the size of the dynamic string exceeds 7960** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors. 7961** 7962** ^The [sqlite3_str_length(X)] method returns the current length, in bytes, 7963** of the dynamic string under construction in [sqlite3_str] object X. 7964** ^The length returned by [sqlite3_str_length(X)] does not include the 7965** zero-termination byte. 7966** 7967** ^The [sqlite3_str_value(X)] method returns a pointer to the current 7968** content of the dynamic string under construction in X. The value 7969** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X 7970** and might be freed or altered by any subsequent method on the same 7971** [sqlite3_str] object. Applications must not used the pointer returned 7972** [sqlite3_str_value(X)] after any subsequent method call on the same 7973** object. ^Applications may change the content of the string returned 7974** by [sqlite3_str_value(X)] as long as they do not write into any bytes 7975** outside the range of 0 to [sqlite3_str_length(X)] and do not read or 7976** write any byte after any subsequent sqlite3_str method call. 7977*/ 7978int sqlite3_str_errcode(sqlite3_str*); 7979int sqlite3_str_length(sqlite3_str*); 7980char *sqlite3_str_value(sqlite3_str*); 7981 7982/* 7983** CAPI3REF: SQLite Runtime Status 7984** 7985** ^These interfaces are used to retrieve runtime status information 7986** about the performance of SQLite, and optionally to reset various 7987** highwater marks. ^The first argument is an integer code for 7988** the specific parameter to measure. ^(Recognized integer codes 7989** are of the form [status parameters | SQLITE_STATUS_...].)^ 7990** ^The current value of the parameter is returned into *pCurrent. 7991** ^The highest recorded value is returned in *pHighwater. ^If the 7992** resetFlag is true, then the highest record value is reset after 7993** *pHighwater is written. ^(Some parameters do not record the highest 7994** value. For those parameters 7995** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7996** ^(Other parameters record only the highwater mark and not the current 7997** value. For these latter parameters nothing is written into *pCurrent.)^ 7998** 7999** ^The sqlite3_status() and sqlite3_status64() routines return 8000** SQLITE_OK on success and a non-zero [error code] on failure. 8001** 8002** If either the current value or the highwater mark is too large to 8003** be represented by a 32-bit integer, then the values returned by 8004** sqlite3_status() are undefined. 8005** 8006** See also: [sqlite3_db_status()] 8007*/ 8008int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 8009int sqlite3_status64( 8010 int op, 8011 sqlite3_int64 *pCurrent, 8012 sqlite3_int64 *pHighwater, 8013 int resetFlag 8014); 8015 8016 8017/* 8018** CAPI3REF: Status Parameters 8019** KEYWORDS: {status parameters} 8020** 8021** These integer constants designate various run-time status parameters 8022** that can be returned by [sqlite3_status()]. 8023** 8024** <dl> 8025** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 8026** <dd>This parameter is the current amount of memory checked out 8027** using [sqlite3_malloc()], either directly or indirectly. The 8028** figure includes calls made to [sqlite3_malloc()] by the application 8029** and internal memory usage by the SQLite library. Auxiliary page-cache 8030** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 8031** this parameter. The amount returned is the sum of the allocation 8032** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 8033** 8034** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 8035** <dd>This parameter records the largest memory allocation request 8036** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 8037** internal equivalents). Only the value returned in the 8038** *pHighwater parameter to [sqlite3_status()] is of interest. 8039** The value written into the *pCurrent parameter is undefined.</dd>)^ 8040** 8041** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 8042** <dd>This parameter records the number of separate memory allocations 8043** currently checked out.</dd>)^ 8044** 8045** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 8046** <dd>This parameter returns the number of pages used out of the 8047** [pagecache memory allocator] that was configured using 8048** [SQLITE_CONFIG_PAGECACHE]. The 8049** value returned is in pages, not in bytes.</dd>)^ 8050** 8051** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 8052** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 8053** <dd>This parameter returns the number of bytes of page cache 8054** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 8055** buffer and where forced to overflow to [sqlite3_malloc()]. The 8056** returned value includes allocations that overflowed because they 8057** where too large (they were larger than the "sz" parameter to 8058** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 8059** no space was left in the page cache.</dd>)^ 8060** 8061** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 8062** <dd>This parameter records the largest memory allocation request 8063** handed to the [pagecache memory allocator]. Only the value returned in the 8064** *pHighwater parameter to [sqlite3_status()] is of interest. 8065** The value written into the *pCurrent parameter is undefined.</dd>)^ 8066** 8067** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 8068** <dd>No longer used.</dd> 8069** 8070** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 8071** <dd>No longer used.</dd> 8072** 8073** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 8074** <dd>No longer used.</dd> 8075** 8076** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 8077** <dd>The *pHighwater parameter records the deepest parser stack. 8078** The *pCurrent value is undefined. The *pHighwater value is only 8079** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 8080** </dl> 8081** 8082** New status parameters may be added from time to time. 8083*/ 8084#define SQLITE_STATUS_MEMORY_USED 0 8085#define SQLITE_STATUS_PAGECACHE_USED 1 8086#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 8087#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 8088#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 8089#define SQLITE_STATUS_MALLOC_SIZE 5 8090#define SQLITE_STATUS_PARSER_STACK 6 8091#define SQLITE_STATUS_PAGECACHE_SIZE 7 8092#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 8093#define SQLITE_STATUS_MALLOC_COUNT 9 8094 8095/* 8096** CAPI3REF: Database Connection Status 8097** METHOD: sqlite3 8098** 8099** ^This interface is used to retrieve runtime status information 8100** about a single [database connection]. ^The first argument is the 8101** database connection object to be interrogated. ^The second argument 8102** is an integer constant, taken from the set of 8103** [SQLITE_DBSTATUS options], that 8104** determines the parameter to interrogate. The set of 8105** [SQLITE_DBSTATUS options] is likely 8106** to grow in future releases of SQLite. 8107** 8108** ^The current value of the requested parameter is written into *pCur 8109** and the highest instantaneous value is written into *pHiwtr. ^If 8110** the resetFlg is true, then the highest instantaneous value is 8111** reset back down to the current value. 8112** 8113** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 8114** non-zero [error code] on failure. 8115** 8116** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 8117*/ 8118int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 8119 8120/* 8121** CAPI3REF: Status Parameters for database connections 8122** KEYWORDS: {SQLITE_DBSTATUS options} 8123** 8124** These constants are the available integer "verbs" that can be passed as 8125** the second argument to the [sqlite3_db_status()] interface. 8126** 8127** New verbs may be added in future releases of SQLite. Existing verbs 8128** might be discontinued. Applications should check the return code from 8129** [sqlite3_db_status()] to make sure that the call worked. 8130** The [sqlite3_db_status()] interface will return a non-zero error code 8131** if a discontinued or unsupported verb is invoked. 8132** 8133** <dl> 8134** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 8135** <dd>This parameter returns the number of lookaside memory slots currently 8136** checked out.</dd>)^ 8137** 8138** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 8139** <dd>This parameter returns the number of malloc attempts that were 8140** satisfied using lookaside memory. Only the high-water value is meaningful; 8141** the current value is always zero.)^ 8142** 8143** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 8144** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 8145** <dd>This parameter returns the number malloc attempts that might have 8146** been satisfied using lookaside memory but failed due to the amount of 8147** memory requested being larger than the lookaside slot size. 8148** Only the high-water value is meaningful; 8149** the current value is always zero.)^ 8150** 8151** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 8152** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 8153** <dd>This parameter returns the number malloc attempts that might have 8154** been satisfied using lookaside memory but failed due to all lookaside 8155** memory already being in use. 8156** Only the high-water value is meaningful; 8157** the current value is always zero.)^ 8158** 8159** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 8160** <dd>This parameter returns the approximate number of bytes of heap 8161** memory used by all pager caches associated with the database connection.)^ 8162** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 8163** 8164** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 8165** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 8166** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 8167** pager cache is shared between two or more connections the bytes of heap 8168** memory used by that pager cache is divided evenly between the attached 8169** connections.)^ In other words, if none of the pager caches associated 8170** with the database connection are shared, this request returns the same 8171** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 8172** shared, the value returned by this call will be smaller than that returned 8173** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 8174** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 8175** 8176** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 8177** <dd>This parameter returns the approximate number of bytes of heap 8178** memory used to store the schema for all databases associated 8179** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 8180** ^The full amount of memory used by the schemas is reported, even if the 8181** schema memory is shared with other database connections due to 8182** [shared cache mode] being enabled. 8183** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 8184** 8185** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 8186** <dd>This parameter returns the approximate number of bytes of heap 8187** and lookaside memory used by all prepared statements associated with 8188** the database connection.)^ 8189** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 8190** </dd> 8191** 8192** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 8193** <dd>This parameter returns the number of pager cache hits that have 8194** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 8195** is always 0. 8196** </dd> 8197** 8198** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 8199** <dd>This parameter returns the number of pager cache misses that have 8200** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 8201** is always 0. 8202** </dd> 8203** 8204** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 8205** <dd>This parameter returns the number of dirty cache entries that have 8206** been written to disk. Specifically, the number of pages written to the 8207** wal file in wal mode databases, or the number of pages written to the 8208** database file in rollback mode databases. Any pages written as part of 8209** transaction rollback or database recovery operations are not included. 8210** If an IO or other error occurs while writing a page to disk, the effect 8211** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 8212** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 8213** </dd> 8214** 8215** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 8216** <dd>This parameter returns the number of dirty cache entries that have 8217** been written to disk in the middle of a transaction due to the page 8218** cache overflowing. Transactions are more efficient if they are written 8219** to disk all at once. When pages spill mid-transaction, that introduces 8220** additional overhead. This parameter can be used help identify 8221** inefficiencies that can be resolved by increasing the cache size. 8222** </dd> 8223** 8224** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 8225** <dd>This parameter returns zero for the current value if and only if 8226** all foreign key constraints (deferred or immediate) have been 8227** resolved.)^ ^The highwater mark is always 0. 8228** </dd> 8229** </dl> 8230*/ 8231#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 8232#define SQLITE_DBSTATUS_CACHE_USED 1 8233#define SQLITE_DBSTATUS_SCHEMA_USED 2 8234#define SQLITE_DBSTATUS_STMT_USED 3 8235#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 8236#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 8237#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 8238#define SQLITE_DBSTATUS_CACHE_HIT 7 8239#define SQLITE_DBSTATUS_CACHE_MISS 8 8240#define SQLITE_DBSTATUS_CACHE_WRITE 9 8241#define SQLITE_DBSTATUS_DEFERRED_FKS 10 8242#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 8243#define SQLITE_DBSTATUS_CACHE_SPILL 12 8244#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 8245 8246 8247/* 8248** CAPI3REF: Prepared Statement Status 8249** METHOD: sqlite3_stmt 8250** 8251** ^(Each prepared statement maintains various 8252** [SQLITE_STMTSTATUS counters] that measure the number 8253** of times it has performed specific operations.)^ These counters can 8254** be used to monitor the performance characteristics of the prepared 8255** statements. For example, if the number of table steps greatly exceeds 8256** the number of table searches or result rows, that would tend to indicate 8257** that the prepared statement is using a full table scan rather than 8258** an index. 8259** 8260** ^(This interface is used to retrieve and reset counter values from 8261** a [prepared statement]. The first argument is the prepared statement 8262** object to be interrogated. The second argument 8263** is an integer code for a specific [SQLITE_STMTSTATUS counter] 8264** to be interrogated.)^ 8265** ^The current value of the requested counter is returned. 8266** ^If the resetFlg is true, then the counter is reset to zero after this 8267** interface call returns. 8268** 8269** See also: [sqlite3_status()] and [sqlite3_db_status()]. 8270*/ 8271int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 8272 8273/* 8274** CAPI3REF: Status Parameters for prepared statements 8275** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 8276** 8277** These preprocessor macros define integer codes that name counter 8278** values associated with the [sqlite3_stmt_status()] interface. 8279** The meanings of the various counters are as follows: 8280** 8281** <dl> 8282** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 8283** <dd>^This is the number of times that SQLite has stepped forward in 8284** a table as part of a full table scan. Large numbers for this counter 8285** may indicate opportunities for performance improvement through 8286** careful use of indices.</dd> 8287** 8288** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 8289** <dd>^This is the number of sort operations that have occurred. 8290** A non-zero value in this counter may indicate an opportunity to 8291** improvement performance through careful use of indices.</dd> 8292** 8293** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 8294** <dd>^This is the number of rows inserted into transient indices that 8295** were created automatically in order to help joins run faster. 8296** A non-zero value in this counter may indicate an opportunity to 8297** improvement performance by adding permanent indices that do not 8298** need to be reinitialized each time the statement is run.</dd> 8299** 8300** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 8301** <dd>^This is the number of virtual machine operations executed 8302** by the prepared statement if that number is less than or equal 8303** to 2147483647. The number of virtual machine operations can be 8304** used as a proxy for the total work done by the prepared statement. 8305** If the number of virtual machine operations exceeds 2147483647 8306** then the value returned by this statement status code is undefined. 8307** 8308** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 8309** <dd>^This is the number of times that the prepare statement has been 8310** automatically regenerated due to schema changes or changes to 8311** [bound parameters] that might affect the query plan. 8312** 8313** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 8314** <dd>^This is the number of times that the prepared statement has 8315** been run. A single "run" for the purposes of this counter is one 8316** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 8317** The counter is incremented on the first [sqlite3_step()] call of each 8318** cycle. 8319** 8320** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 8321** <dd>^This is the approximate number of bytes of heap memory 8322** used to store the prepared statement. ^This value is not actually 8323** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 8324** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 8325** </dd> 8326** </dl> 8327*/ 8328#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 8329#define SQLITE_STMTSTATUS_SORT 2 8330#define SQLITE_STMTSTATUS_AUTOINDEX 3 8331#define SQLITE_STMTSTATUS_VM_STEP 4 8332#define SQLITE_STMTSTATUS_REPREPARE 5 8333#define SQLITE_STMTSTATUS_RUN 6 8334#define SQLITE_STMTSTATUS_MEMUSED 99 8335 8336/* 8337** CAPI3REF: Custom Page Cache Object 8338** 8339** The sqlite3_pcache type is opaque. It is implemented by 8340** the pluggable module. The SQLite core has no knowledge of 8341** its size or internal structure and never deals with the 8342** sqlite3_pcache object except by holding and passing pointers 8343** to the object. 8344** 8345** See [sqlite3_pcache_methods2] for additional information. 8346*/ 8347typedef struct sqlite3_pcache sqlite3_pcache; 8348 8349/* 8350** CAPI3REF: Custom Page Cache Object 8351** 8352** The sqlite3_pcache_page object represents a single page in the 8353** page cache. The page cache will allocate instances of this 8354** object. Various methods of the page cache use pointers to instances 8355** of this object as parameters or as their return value. 8356** 8357** See [sqlite3_pcache_methods2] for additional information. 8358*/ 8359typedef struct sqlite3_pcache_page sqlite3_pcache_page; 8360struct sqlite3_pcache_page { 8361 void *pBuf; /* The content of the page */ 8362 void *pExtra; /* Extra information associated with the page */ 8363}; 8364 8365/* 8366** CAPI3REF: Application Defined Page Cache. 8367** KEYWORDS: {page cache} 8368** 8369** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 8370** register an alternative page cache implementation by passing in an 8371** instance of the sqlite3_pcache_methods2 structure.)^ 8372** In many applications, most of the heap memory allocated by 8373** SQLite is used for the page cache. 8374** By implementing a 8375** custom page cache using this API, an application can better control 8376** the amount of memory consumed by SQLite, the way in which 8377** that memory is allocated and released, and the policies used to 8378** determine exactly which parts of a database file are cached and for 8379** how long. 8380** 8381** The alternative page cache mechanism is an 8382** extreme measure that is only needed by the most demanding applications. 8383** The built-in page cache is recommended for most uses. 8384** 8385** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 8386** internal buffer by SQLite within the call to [sqlite3_config]. Hence 8387** the application may discard the parameter after the call to 8388** [sqlite3_config()] returns.)^ 8389** 8390** [[the xInit() page cache method]] 8391** ^(The xInit() method is called once for each effective 8392** call to [sqlite3_initialize()])^ 8393** (usually only once during the lifetime of the process). ^(The xInit() 8394** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 8395** The intent of the xInit() method is to set up global data structures 8396** required by the custom page cache implementation. 8397** ^(If the xInit() method is NULL, then the 8398** built-in default page cache is used instead of the application defined 8399** page cache.)^ 8400** 8401** [[the xShutdown() page cache method]] 8402** ^The xShutdown() method is called by [sqlite3_shutdown()]. 8403** It can be used to clean up 8404** any outstanding resources before process shutdown, if required. 8405** ^The xShutdown() method may be NULL. 8406** 8407** ^SQLite automatically serializes calls to the xInit method, 8408** so the xInit method need not be threadsafe. ^The 8409** xShutdown method is only called from [sqlite3_shutdown()] so it does 8410** not need to be threadsafe either. All other methods must be threadsafe 8411** in multithreaded applications. 8412** 8413** ^SQLite will never invoke xInit() more than once without an intervening 8414** call to xShutdown(). 8415** 8416** [[the xCreate() page cache methods]] 8417** ^SQLite invokes the xCreate() method to construct a new cache instance. 8418** SQLite will typically create one cache instance for each open database file, 8419** though this is not guaranteed. ^The 8420** first parameter, szPage, is the size in bytes of the pages that must 8421** be allocated by the cache. ^szPage will always a power of two. ^The 8422** second parameter szExtra is a number of bytes of extra storage 8423** associated with each page cache entry. ^The szExtra parameter will 8424** a number less than 250. SQLite will use the 8425** extra szExtra bytes on each page to store metadata about the underlying 8426** database page on disk. The value passed into szExtra depends 8427** on the SQLite version, the target platform, and how SQLite was compiled. 8428** ^The third argument to xCreate(), bPurgeable, is true if the cache being 8429** created will be used to cache database pages of a file stored on disk, or 8430** false if it is used for an in-memory database. The cache implementation 8431** does not have to do anything special based with the value of bPurgeable; 8432** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 8433** never invoke xUnpin() except to deliberately delete a page. 8434** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 8435** false will always have the "discard" flag set to true. 8436** ^Hence, a cache created with bPurgeable false will 8437** never contain any unpinned pages. 8438** 8439** [[the xCachesize() page cache method]] 8440** ^(The xCachesize() method may be called at any time by SQLite to set the 8441** suggested maximum cache-size (number of pages stored by) the cache 8442** instance passed as the first argument. This is the value configured using 8443** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 8444** parameter, the implementation is not required to do anything with this 8445** value; it is advisory only. 8446** 8447** [[the xPagecount() page cache methods]] 8448** The xPagecount() method must return the number of pages currently 8449** stored in the cache, both pinned and unpinned. 8450** 8451** [[the xFetch() page cache methods]] 8452** The xFetch() method locates a page in the cache and returns a pointer to 8453** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 8454** The pBuf element of the returned sqlite3_pcache_page object will be a 8455** pointer to a buffer of szPage bytes used to store the content of a 8456** single database page. The pExtra element of sqlite3_pcache_page will be 8457** a pointer to the szExtra bytes of extra storage that SQLite has requested 8458** for each entry in the page cache. 8459** 8460** The page to be fetched is determined by the key. ^The minimum key value 8461** is 1. After it has been retrieved using xFetch, the page is considered 8462** to be "pinned". 8463** 8464** If the requested page is already in the page cache, then the page cache 8465** implementation must return a pointer to the page buffer with its content 8466** intact. If the requested page is not already in the cache, then the 8467** cache implementation should use the value of the createFlag 8468** parameter to help it determined what action to take: 8469** 8470** <table border=1 width=85% align=center> 8471** <tr><th> createFlag <th> Behavior when page is not already in cache 8472** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 8473** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 8474** Otherwise return NULL. 8475** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 8476** NULL if allocating a new page is effectively impossible. 8477** </table> 8478** 8479** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 8480** will only use a createFlag of 2 after a prior call with a createFlag of 1 8481** failed.)^ In between the xFetch() calls, SQLite may 8482** attempt to unpin one or more cache pages by spilling the content of 8483** pinned pages to disk and synching the operating system disk cache. 8484** 8485** [[the xUnpin() page cache method]] 8486** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 8487** as its second argument. If the third parameter, discard, is non-zero, 8488** then the page must be evicted from the cache. 8489** ^If the discard parameter is 8490** zero, then the page may be discarded or retained at the discretion of 8491** page cache implementation. ^The page cache implementation 8492** may choose to evict unpinned pages at any time. 8493** 8494** The cache must not perform any reference counting. A single 8495** call to xUnpin() unpins the page regardless of the number of prior calls 8496** to xFetch(). 8497** 8498** [[the xRekey() page cache methods]] 8499** The xRekey() method is used to change the key value associated with the 8500** page passed as the second argument. If the cache 8501** previously contains an entry associated with newKey, it must be 8502** discarded. ^Any prior cache entry associated with newKey is guaranteed not 8503** to be pinned. 8504** 8505** When SQLite calls the xTruncate() method, the cache must discard all 8506** existing cache entries with page numbers (keys) greater than or equal 8507** to the value of the iLimit parameter passed to xTruncate(). If any 8508** of these pages are pinned, they are implicitly unpinned, meaning that 8509** they can be safely discarded. 8510** 8511** [[the xDestroy() page cache method]] 8512** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 8513** All resources associated with the specified cache should be freed. ^After 8514** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 8515** handle invalid, and will not use it with any other sqlite3_pcache_methods2 8516** functions. 8517** 8518** [[the xShrink() page cache method]] 8519** ^SQLite invokes the xShrink() method when it wants the page cache to 8520** free up as much of heap memory as possible. The page cache implementation 8521** is not obligated to free any memory, but well-behaved implementations should 8522** do their best. 8523*/ 8524typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 8525struct sqlite3_pcache_methods2 { 8526 int iVersion; 8527 void *pArg; 8528 int (*xInit)(void*); 8529 void (*xShutdown)(void*); 8530 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 8531 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8532 int (*xPagecount)(sqlite3_pcache*); 8533 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8534 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 8535 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 8536 unsigned oldKey, unsigned newKey); 8537 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8538 void (*xDestroy)(sqlite3_pcache*); 8539 void (*xShrink)(sqlite3_pcache*); 8540}; 8541 8542/* 8543** This is the obsolete pcache_methods object that has now been replaced 8544** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 8545** retained in the header file for backwards compatibility only. 8546*/ 8547typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 8548struct sqlite3_pcache_methods { 8549 void *pArg; 8550 int (*xInit)(void*); 8551 void (*xShutdown)(void*); 8552 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 8553 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8554 int (*xPagecount)(sqlite3_pcache*); 8555 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8556 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 8557 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 8558 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8559 void (*xDestroy)(sqlite3_pcache*); 8560}; 8561 8562 8563/* 8564** CAPI3REF: Online Backup Object 8565** 8566** The sqlite3_backup object records state information about an ongoing 8567** online backup operation. ^The sqlite3_backup object is created by 8568** a call to [sqlite3_backup_init()] and is destroyed by a call to 8569** [sqlite3_backup_finish()]. 8570** 8571** See Also: [Using the SQLite Online Backup API] 8572*/ 8573typedef struct sqlite3_backup sqlite3_backup; 8574 8575/* 8576** CAPI3REF: Online Backup API. 8577** 8578** The backup API copies the content of one database into another. 8579** It is useful either for creating backups of databases or 8580** for copying in-memory databases to or from persistent files. 8581** 8582** See Also: [Using the SQLite Online Backup API] 8583** 8584** ^SQLite holds a write transaction open on the destination database file 8585** for the duration of the backup operation. 8586** ^The source database is read-locked only while it is being read; 8587** it is not locked continuously for the entire backup operation. 8588** ^Thus, the backup may be performed on a live source database without 8589** preventing other database connections from 8590** reading or writing to the source database while the backup is underway. 8591** 8592** ^(To perform a backup operation: 8593** <ol> 8594** <li><b>sqlite3_backup_init()</b> is called once to initialize the 8595** backup, 8596** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 8597** the data between the two databases, and finally 8598** <li><b>sqlite3_backup_finish()</b> is called to release all resources 8599** associated with the backup operation. 8600** </ol>)^ 8601** There should be exactly one call to sqlite3_backup_finish() for each 8602** successful call to sqlite3_backup_init(). 8603** 8604** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 8605** 8606** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 8607** [database connection] associated with the destination database 8608** and the database name, respectively. 8609** ^The database name is "main" for the main database, "temp" for the 8610** temporary database, or the name specified after the AS keyword in 8611** an [ATTACH] statement for an attached database. 8612** ^The S and M arguments passed to 8613** sqlite3_backup_init(D,N,S,M) identify the [database connection] 8614** and database name of the source database, respectively. 8615** ^The source and destination [database connections] (parameters S and D) 8616** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 8617** an error. 8618** 8619** ^A call to sqlite3_backup_init() will fail, returning NULL, if 8620** there is already a read or read-write transaction open on the 8621** destination database. 8622** 8623** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 8624** returned and an error code and error message are stored in the 8625** destination [database connection] D. 8626** ^The error code and message for the failed call to sqlite3_backup_init() 8627** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 8628** [sqlite3_errmsg16()] functions. 8629** ^A successful call to sqlite3_backup_init() returns a pointer to an 8630** [sqlite3_backup] object. 8631** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 8632** sqlite3_backup_finish() functions to perform the specified backup 8633** operation. 8634** 8635** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 8636** 8637** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 8638** the source and destination databases specified by [sqlite3_backup] object B. 8639** ^If N is negative, all remaining source pages are copied. 8640** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 8641** are still more pages to be copied, then the function returns [SQLITE_OK]. 8642** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 8643** from source to destination, then it returns [SQLITE_DONE]. 8644** ^If an error occurs while running sqlite3_backup_step(B,N), 8645** then an [error code] is returned. ^As well as [SQLITE_OK] and 8646** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 8647** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 8648** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 8649** 8650** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 8651** <ol> 8652** <li> the destination database was opened read-only, or 8653** <li> the destination database is using write-ahead-log journaling 8654** and the destination and source page sizes differ, or 8655** <li> the destination database is an in-memory database and the 8656** destination and source page sizes differ. 8657** </ol>)^ 8658** 8659** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 8660** the [sqlite3_busy_handler | busy-handler function] 8661** is invoked (if one is specified). ^If the 8662** busy-handler returns non-zero before the lock is available, then 8663** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 8664** sqlite3_backup_step() can be retried later. ^If the source 8665** [database connection] 8666** is being used to write to the source database when sqlite3_backup_step() 8667** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 8668** case the call to sqlite3_backup_step() can be retried later on. ^(If 8669** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 8670** [SQLITE_READONLY] is returned, then 8671** there is no point in retrying the call to sqlite3_backup_step(). These 8672** errors are considered fatal.)^ The application must accept 8673** that the backup operation has failed and pass the backup operation handle 8674** to the sqlite3_backup_finish() to release associated resources. 8675** 8676** ^The first call to sqlite3_backup_step() obtains an exclusive lock 8677** on the destination file. ^The exclusive lock is not released until either 8678** sqlite3_backup_finish() is called or the backup operation is complete 8679** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 8680** sqlite3_backup_step() obtains a [shared lock] on the source database that 8681** lasts for the duration of the sqlite3_backup_step() call. 8682** ^Because the source database is not locked between calls to 8683** sqlite3_backup_step(), the source database may be modified mid-way 8684** through the backup process. ^If the source database is modified by an 8685** external process or via a database connection other than the one being 8686** used by the backup operation, then the backup will be automatically 8687** restarted by the next call to sqlite3_backup_step(). ^If the source 8688** database is modified by the using the same database connection as is used 8689** by the backup operation, then the backup database is automatically 8690** updated at the same time. 8691** 8692** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 8693** 8694** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 8695** application wishes to abandon the backup operation, the application 8696** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 8697** ^The sqlite3_backup_finish() interfaces releases all 8698** resources associated with the [sqlite3_backup] object. 8699** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 8700** active write-transaction on the destination database is rolled back. 8701** The [sqlite3_backup] object is invalid 8702** and may not be used following a call to sqlite3_backup_finish(). 8703** 8704** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 8705** sqlite3_backup_step() errors occurred, regardless or whether or not 8706** sqlite3_backup_step() completed. 8707** ^If an out-of-memory condition or IO error occurred during any prior 8708** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 8709** sqlite3_backup_finish() returns the corresponding [error code]. 8710** 8711** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 8712** is not a permanent error and does not affect the return value of 8713** sqlite3_backup_finish(). 8714** 8715** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 8716** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 8717** 8718** ^The sqlite3_backup_remaining() routine returns the number of pages still 8719** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 8720** ^The sqlite3_backup_pagecount() routine returns the total number of pages 8721** in the source database at the conclusion of the most recent 8722** sqlite3_backup_step(). 8723** ^(The values returned by these functions are only updated by 8724** sqlite3_backup_step(). If the source database is modified in a way that 8725** changes the size of the source database or the number of pages remaining, 8726** those changes are not reflected in the output of sqlite3_backup_pagecount() 8727** and sqlite3_backup_remaining() until after the next 8728** sqlite3_backup_step().)^ 8729** 8730** <b>Concurrent Usage of Database Handles</b> 8731** 8732** ^The source [database connection] may be used by the application for other 8733** purposes while a backup operation is underway or being initialized. 8734** ^If SQLite is compiled and configured to support threadsafe database 8735** connections, then the source database connection may be used concurrently 8736** from within other threads. 8737** 8738** However, the application must guarantee that the destination 8739** [database connection] is not passed to any other API (by any thread) after 8740** sqlite3_backup_init() is called and before the corresponding call to 8741** sqlite3_backup_finish(). SQLite does not currently check to see 8742** if the application incorrectly accesses the destination [database connection] 8743** and so no error code is reported, but the operations may malfunction 8744** nevertheless. Use of the destination database connection while a 8745** backup is in progress might also also cause a mutex deadlock. 8746** 8747** If running in [shared cache mode], the application must 8748** guarantee that the shared cache used by the destination database 8749** is not accessed while the backup is running. In practice this means 8750** that the application must guarantee that the disk file being 8751** backed up to is not accessed by any connection within the process, 8752** not just the specific connection that was passed to sqlite3_backup_init(). 8753** 8754** The [sqlite3_backup] object itself is partially threadsafe. Multiple 8755** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 8756** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 8757** APIs are not strictly speaking threadsafe. If they are invoked at the 8758** same time as another thread is invoking sqlite3_backup_step() it is 8759** possible that they return invalid values. 8760*/ 8761sqlite3_backup *sqlite3_backup_init( 8762 sqlite3 *pDest, /* Destination database handle */ 8763 const char *zDestName, /* Destination database name */ 8764 sqlite3 *pSource, /* Source database handle */ 8765 const char *zSourceName /* Source database name */ 8766); 8767int sqlite3_backup_step(sqlite3_backup *p, int nPage); 8768int sqlite3_backup_finish(sqlite3_backup *p); 8769int sqlite3_backup_remaining(sqlite3_backup *p); 8770int sqlite3_backup_pagecount(sqlite3_backup *p); 8771 8772/* 8773** CAPI3REF: Unlock Notification 8774** METHOD: sqlite3 8775** 8776** ^When running in shared-cache mode, a database operation may fail with 8777** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 8778** individual tables within the shared-cache cannot be obtained. See 8779** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 8780** ^This API may be used to register a callback that SQLite will invoke 8781** when the connection currently holding the required lock relinquishes it. 8782** ^This API is only available if the library was compiled with the 8783** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 8784** 8785** See Also: [Using the SQLite Unlock Notification Feature]. 8786** 8787** ^Shared-cache locks are released when a database connection concludes 8788** its current transaction, either by committing it or rolling it back. 8789** 8790** ^When a connection (known as the blocked connection) fails to obtain a 8791** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 8792** identity of the database connection (the blocking connection) that 8793** has locked the required resource is stored internally. ^After an 8794** application receives an SQLITE_LOCKED error, it may call the 8795** sqlite3_unlock_notify() method with the blocked connection handle as 8796** the first argument to register for a callback that will be invoked 8797** when the blocking connections current transaction is concluded. ^The 8798** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 8799** call that concludes the blocking connection's transaction. 8800** 8801** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 8802** there is a chance that the blocking connection will have already 8803** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 8804** If this happens, then the specified callback is invoked immediately, 8805** from within the call to sqlite3_unlock_notify().)^ 8806** 8807** ^If the blocked connection is attempting to obtain a write-lock on a 8808** shared-cache table, and more than one other connection currently holds 8809** a read-lock on the same table, then SQLite arbitrarily selects one of 8810** the other connections to use as the blocking connection. 8811** 8812** ^(There may be at most one unlock-notify callback registered by a 8813** blocked connection. If sqlite3_unlock_notify() is called when the 8814** blocked connection already has a registered unlock-notify callback, 8815** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 8816** called with a NULL pointer as its second argument, then any existing 8817** unlock-notify callback is canceled. ^The blocked connections 8818** unlock-notify callback may also be canceled by closing the blocked 8819** connection using [sqlite3_close()]. 8820** 8821** The unlock-notify callback is not reentrant. If an application invokes 8822** any sqlite3_xxx API functions from within an unlock-notify callback, a 8823** crash or deadlock may be the result. 8824** 8825** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 8826** returns SQLITE_OK. 8827** 8828** <b>Callback Invocation Details</b> 8829** 8830** When an unlock-notify callback is registered, the application provides a 8831** single void* pointer that is passed to the callback when it is invoked. 8832** However, the signature of the callback function allows SQLite to pass 8833** it an array of void* context pointers. The first argument passed to 8834** an unlock-notify callback is a pointer to an array of void* pointers, 8835** and the second is the number of entries in the array. 8836** 8837** When a blocking connection's transaction is concluded, there may be 8838** more than one blocked connection that has registered for an unlock-notify 8839** callback. ^If two or more such blocked connections have specified the 8840** same callback function, then instead of invoking the callback function 8841** multiple times, it is invoked once with the set of void* context pointers 8842** specified by the blocked connections bundled together into an array. 8843** This gives the application an opportunity to prioritize any actions 8844** related to the set of unblocked database connections. 8845** 8846** <b>Deadlock Detection</b> 8847** 8848** Assuming that after registering for an unlock-notify callback a 8849** database waits for the callback to be issued before taking any further 8850** action (a reasonable assumption), then using this API may cause the 8851** application to deadlock. For example, if connection X is waiting for 8852** connection Y's transaction to be concluded, and similarly connection 8853** Y is waiting on connection X's transaction, then neither connection 8854** will proceed and the system may remain deadlocked indefinitely. 8855** 8856** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 8857** detection. ^If a given call to sqlite3_unlock_notify() would put the 8858** system in a deadlocked state, then SQLITE_LOCKED is returned and no 8859** unlock-notify callback is registered. The system is said to be in 8860** a deadlocked state if connection A has registered for an unlock-notify 8861** callback on the conclusion of connection B's transaction, and connection 8862** B has itself registered for an unlock-notify callback when connection 8863** A's transaction is concluded. ^Indirect deadlock is also detected, so 8864** the system is also considered to be deadlocked if connection B has 8865** registered for an unlock-notify callback on the conclusion of connection 8866** C's transaction, where connection C is waiting on connection A. ^Any 8867** number of levels of indirection are allowed. 8868** 8869** <b>The "DROP TABLE" Exception</b> 8870** 8871** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 8872** always appropriate to call sqlite3_unlock_notify(). There is however, 8873** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 8874** SQLite checks if there are any currently executing SELECT statements 8875** that belong to the same connection. If there are, SQLITE_LOCKED is 8876** returned. In this case there is no "blocking connection", so invoking 8877** sqlite3_unlock_notify() results in the unlock-notify callback being 8878** invoked immediately. If the application then re-attempts the "DROP TABLE" 8879** or "DROP INDEX" query, an infinite loop might be the result. 8880** 8881** One way around this problem is to check the extended error code returned 8882** by an sqlite3_step() call. ^(If there is a blocking connection, then the 8883** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 8884** the special "DROP TABLE/INDEX" case, the extended error code is just 8885** SQLITE_LOCKED.)^ 8886*/ 8887int sqlite3_unlock_notify( 8888 sqlite3 *pBlocked, /* Waiting connection */ 8889 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 8890 void *pNotifyArg /* Argument to pass to xNotify */ 8891); 8892 8893 8894/* 8895** CAPI3REF: String Comparison 8896** 8897** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 8898** and extensions to compare the contents of two buffers containing UTF-8 8899** strings in a case-independent fashion, using the same definition of "case 8900** independence" that SQLite uses internally when comparing identifiers. 8901*/ 8902int sqlite3_stricmp(const char *, const char *); 8903int sqlite3_strnicmp(const char *, const char *, int); 8904 8905/* 8906** CAPI3REF: String Globbing 8907* 8908** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 8909** string X matches the [GLOB] pattern P. 8910** ^The definition of [GLOB] pattern matching used in 8911** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 8912** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 8913** is case sensitive. 8914** 8915** Note that this routine returns zero on a match and non-zero if the strings 8916** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8917** 8918** See also: [sqlite3_strlike()]. 8919*/ 8920int sqlite3_strglob(const char *zGlob, const char *zStr); 8921 8922/* 8923** CAPI3REF: String LIKE Matching 8924* 8925** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 8926** string X matches the [LIKE] pattern P with escape character E. 8927** ^The definition of [LIKE] pattern matching used in 8928** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 8929** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 8930** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 8931** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 8932** insensitive - equivalent upper and lower case ASCII characters match 8933** one another. 8934** 8935** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 8936** only ASCII characters are case folded. 8937** 8938** Note that this routine returns zero on a match and non-zero if the strings 8939** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8940** 8941** See also: [sqlite3_strglob()]. 8942*/ 8943int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8944 8945/* 8946** CAPI3REF: Error Logging Interface 8947** 8948** ^The [sqlite3_log()] interface writes a message into the [error log] 8949** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8950** ^If logging is enabled, the zFormat string and subsequent arguments are 8951** used with [sqlite3_snprintf()] to generate the final output string. 8952** 8953** The sqlite3_log() interface is intended for use by extensions such as 8954** virtual tables, collating functions, and SQL functions. While there is 8955** nothing to prevent an application from calling sqlite3_log(), doing so 8956** is considered bad form. 8957** 8958** The zFormat string must not be NULL. 8959** 8960** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8961** will not use dynamically allocated memory. The log message is stored in 8962** a fixed-length buffer on the stack. If the log message is longer than 8963** a few hundred characters, it will be truncated to the length of the 8964** buffer. 8965*/ 8966void sqlite3_log(int iErrCode, const char *zFormat, ...); 8967 8968/* 8969** CAPI3REF: Write-Ahead Log Commit Hook 8970** METHOD: sqlite3 8971** 8972** ^The [sqlite3_wal_hook()] function is used to register a callback that 8973** is invoked each time data is committed to a database in wal mode. 8974** 8975** ^(The callback is invoked by SQLite after the commit has taken place and 8976** the associated write-lock on the database released)^, so the implementation 8977** may read, write or [checkpoint] the database as required. 8978** 8979** ^The first parameter passed to the callback function when it is invoked 8980** is a copy of the third parameter passed to sqlite3_wal_hook() when 8981** registering the callback. ^The second is a copy of the database handle. 8982** ^The third parameter is the name of the database that was written to - 8983** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8984** is the number of pages currently in the write-ahead log file, 8985** including those that were just committed. 8986** 8987** The callback function should normally return [SQLITE_OK]. ^If an error 8988** code is returned, that error will propagate back up through the 8989** SQLite code base to cause the statement that provoked the callback 8990** to report an error, though the commit will have still occurred. If the 8991** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8992** that does not correspond to any valid SQLite error code, the results 8993** are undefined. 8994** 8995** A single database handle may have at most a single write-ahead log callback 8996** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8997** previously registered write-ahead log callback. ^Note that the 8998** [sqlite3_wal_autocheckpoint()] interface and the 8999** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 9000** overwrite any prior [sqlite3_wal_hook()] settings. 9001*/ 9002void *sqlite3_wal_hook( 9003 sqlite3*, 9004 int(*)(void *,sqlite3*,const char*,int), 9005 void* 9006); 9007 9008/* 9009** CAPI3REF: Configure an auto-checkpoint 9010** METHOD: sqlite3 9011** 9012** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 9013** [sqlite3_wal_hook()] that causes any database on [database connection] D 9014** to automatically [checkpoint] 9015** after committing a transaction if there are N or 9016** more frames in the [write-ahead log] file. ^Passing zero or 9017** a negative value as the nFrame parameter disables automatic 9018** checkpoints entirely. 9019** 9020** ^The callback registered by this function replaces any existing callback 9021** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 9022** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 9023** configured by this function. 9024** 9025** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 9026** from SQL. 9027** 9028** ^Checkpoints initiated by this mechanism are 9029** [sqlite3_wal_checkpoint_v2|PASSIVE]. 9030** 9031** ^Every new [database connection] defaults to having the auto-checkpoint 9032** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 9033** pages. The use of this interface 9034** is only necessary if the default setting is found to be suboptimal 9035** for a particular application. 9036*/ 9037int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 9038 9039/* 9040** CAPI3REF: Checkpoint a database 9041** METHOD: sqlite3 9042** 9043** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 9044** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 9045** 9046** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 9047** [write-ahead log] for database X on [database connection] D to be 9048** transferred into the database file and for the write-ahead log to 9049** be reset. See the [checkpointing] documentation for addition 9050** information. 9051** 9052** This interface used to be the only way to cause a checkpoint to 9053** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 9054** interface was added. This interface is retained for backwards 9055** compatibility and as a convenience for applications that need to manually 9056** start a callback but which do not need the full power (and corresponding 9057** complication) of [sqlite3_wal_checkpoint_v2()]. 9058*/ 9059int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 9060 9061/* 9062** CAPI3REF: Checkpoint a database 9063** METHOD: sqlite3 9064** 9065** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 9066** operation on database X of [database connection] D in mode M. Status 9067** information is written back into integers pointed to by L and C.)^ 9068** ^(The M parameter must be a valid [checkpoint mode]:)^ 9069** 9070** <dl> 9071** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 9072** ^Checkpoint as many frames as possible without waiting for any database 9073** readers or writers to finish, then sync the database file if all frames 9074** in the log were checkpointed. ^The [busy-handler callback] 9075** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 9076** ^On the other hand, passive mode might leave the checkpoint unfinished 9077** if there are concurrent readers or writers. 9078** 9079** <dt>SQLITE_CHECKPOINT_FULL<dd> 9080** ^This mode blocks (it invokes the 9081** [sqlite3_busy_handler|busy-handler callback]) until there is no 9082** database writer and all readers are reading from the most recent database 9083** snapshot. ^It then checkpoints all frames in the log file and syncs the 9084** database file. ^This mode blocks new database writers while it is pending, 9085** but new database readers are allowed to continue unimpeded. 9086** 9087** <dt>SQLITE_CHECKPOINT_RESTART<dd> 9088** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 9089** that after checkpointing the log file it blocks (calls the 9090** [busy-handler callback]) 9091** until all readers are reading from the database file only. ^This ensures 9092** that the next writer will restart the log file from the beginning. 9093** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 9094** database writer attempts while it is pending, but does not impede readers. 9095** 9096** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 9097** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 9098** addition that it also truncates the log file to zero bytes just prior 9099** to a successful return. 9100** </dl> 9101** 9102** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 9103** the log file or to -1 if the checkpoint could not run because 9104** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 9105** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 9106** log file (including any that were already checkpointed before the function 9107** was called) or to -1 if the checkpoint could not run due to an error or 9108** because the database is not in WAL mode. ^Note that upon successful 9109** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 9110** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 9111** 9112** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 9113** any other process is running a checkpoint operation at the same time, the 9114** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 9115** busy-handler configured, it will not be invoked in this case. 9116** 9117** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 9118** exclusive "writer" lock on the database file. ^If the writer lock cannot be 9119** obtained immediately, and a busy-handler is configured, it is invoked and 9120** the writer lock retried until either the busy-handler returns 0 or the lock 9121** is successfully obtained. ^The busy-handler is also invoked while waiting for 9122** database readers as described above. ^If the busy-handler returns 0 before 9123** the writer lock is obtained or while waiting for database readers, the 9124** checkpoint operation proceeds from that point in the same way as 9125** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 9126** without blocking any further. ^SQLITE_BUSY is returned in this case. 9127** 9128** ^If parameter zDb is NULL or points to a zero length string, then the 9129** specified operation is attempted on all WAL databases [attached] to 9130** [database connection] db. In this case the 9131** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 9132** an SQLITE_BUSY error is encountered when processing one or more of the 9133** attached WAL databases, the operation is still attempted on any remaining 9134** attached databases and SQLITE_BUSY is returned at the end. ^If any other 9135** error occurs while processing an attached database, processing is abandoned 9136** and the error code is returned to the caller immediately. ^If no error 9137** (SQLITE_BUSY or otherwise) is encountered while processing the attached 9138** databases, SQLITE_OK is returned. 9139** 9140** ^If database zDb is the name of an attached database that is not in WAL 9141** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 9142** zDb is not NULL (or a zero length string) and is not the name of any 9143** attached database, SQLITE_ERROR is returned to the caller. 9144** 9145** ^Unless it returns SQLITE_MISUSE, 9146** the sqlite3_wal_checkpoint_v2() interface 9147** sets the error information that is queried by 9148** [sqlite3_errcode()] and [sqlite3_errmsg()]. 9149** 9150** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 9151** from SQL. 9152*/ 9153int sqlite3_wal_checkpoint_v2( 9154 sqlite3 *db, /* Database handle */ 9155 const char *zDb, /* Name of attached database (or NULL) */ 9156 int eMode, /* SQLITE_CHECKPOINT_* value */ 9157 int *pnLog, /* OUT: Size of WAL log in frames */ 9158 int *pnCkpt /* OUT: Total number of frames checkpointed */ 9159); 9160 9161/* 9162** CAPI3REF: Checkpoint Mode Values 9163** KEYWORDS: {checkpoint mode} 9164** 9165** These constants define all valid values for the "checkpoint mode" passed 9166** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 9167** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 9168** meaning of each of these checkpoint modes. 9169*/ 9170#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 9171#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 9172#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 9173#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 9174 9175/* 9176** CAPI3REF: Virtual Table Interface Configuration 9177** 9178** This function may be called by either the [xConnect] or [xCreate] method 9179** of a [virtual table] implementation to configure 9180** various facets of the virtual table interface. 9181** 9182** If this interface is invoked outside the context of an xConnect or 9183** xCreate virtual table method then the behavior is undefined. 9184** 9185** In the call sqlite3_vtab_config(D,C,...) the D parameter is the 9186** [database connection] in which the virtual table is being created and 9187** which is passed in as the first argument to the [xConnect] or [xCreate] 9188** method that is invoking sqlite3_vtab_config(). The C parameter is one 9189** of the [virtual table configuration options]. The presence and meaning 9190** of parameters after C depend on which [virtual table configuration option] 9191** is used. 9192*/ 9193int sqlite3_vtab_config(sqlite3*, int op, ...); 9194 9195/* 9196** CAPI3REF: Virtual Table Configuration Options 9197** KEYWORDS: {virtual table configuration options} 9198** KEYWORDS: {virtual table configuration option} 9199** 9200** These macros define the various options to the 9201** [sqlite3_vtab_config()] interface that [virtual table] implementations 9202** can use to customize and optimize their behavior. 9203** 9204** <dl> 9205** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]] 9206** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt> 9207** <dd>Calls of the form 9208** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 9209** where X is an integer. If X is zero, then the [virtual table] whose 9210** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 9211** support constraints. In this configuration (which is the default) if 9212** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 9213** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 9214** specified as part of the users SQL statement, regardless of the actual 9215** ON CONFLICT mode specified. 9216** 9217** If X is non-zero, then the virtual table implementation guarantees 9218** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 9219** any modifications to internal or persistent data structures have been made. 9220** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 9221** is able to roll back a statement or database transaction, and abandon 9222** or continue processing the current SQL statement as appropriate. 9223** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 9224** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 9225** had been ABORT. 9226** 9227** Virtual table implementations that are required to handle OR REPLACE 9228** must do so within the [xUpdate] method. If a call to the 9229** [sqlite3_vtab_on_conflict()] function indicates that the current ON 9230** CONFLICT policy is REPLACE, the virtual table implementation should 9231** silently replace the appropriate rows within the xUpdate callback and 9232** return SQLITE_OK. Or, if this is not possible, it may return 9233** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 9234** constraint handling. 9235** </dd> 9236** 9237** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt> 9238** <dd>Calls of the form 9239** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the 9240** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9241** prohibits that virtual table from being used from within triggers and 9242** views. 9243** </dd> 9244** 9245** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt> 9246** <dd>Calls of the form 9247** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the 9248** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9249** identify that virtual table as being safe to use from within triggers 9250** and views. Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the 9251** virtual table can do no serious harm even if it is controlled by a 9252** malicious hacker. Developers should avoid setting the SQLITE_VTAB_INNOCUOUS 9253** flag unless absolutely necessary. 9254** </dd> 9255** </dl> 9256*/ 9257#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 9258#define SQLITE_VTAB_INNOCUOUS 2 9259#define SQLITE_VTAB_DIRECTONLY 3 9260 9261/* 9262** CAPI3REF: Determine The Virtual Table Conflict Policy 9263** 9264** This function may only be called from within a call to the [xUpdate] method 9265** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 9266** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 9267** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 9268** of the SQL statement that triggered the call to the [xUpdate] method of the 9269** [virtual table]. 9270*/ 9271int sqlite3_vtab_on_conflict(sqlite3 *); 9272 9273/* 9274** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 9275** 9276** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 9277** method of a [virtual table], then it might return true if the 9278** column is being fetched as part of an UPDATE operation during which the 9279** column value will not change. The virtual table implementation can use 9280** this hint as permission to substitute a return value that is less 9281** expensive to compute and that the corresponding 9282** [xUpdate] method understands as a "no-change" value. 9283** 9284** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 9285** the column is not changed by the UPDATE statement, then the xColumn 9286** method can optionally return without setting a result, without calling 9287** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 9288** In that case, [sqlite3_value_nochange(X)] will return true for the 9289** same column in the [xUpdate] method. 9290** 9291** The sqlite3_vtab_nochange() routine is an optimization. Virtual table 9292** implementations should continue to give a correct answer even if the 9293** sqlite3_vtab_nochange() interface were to always return false. In the 9294** current implementation, the sqlite3_vtab_nochange() interface does always 9295** returns false for the enhanced [UPDATE FROM] statement. 9296*/ 9297int sqlite3_vtab_nochange(sqlite3_context*); 9298 9299/* 9300** CAPI3REF: Determine The Collation For a Virtual Table Constraint 9301** 9302** This function may only be called from within a call to the [xBestIndex] 9303** method of a [virtual table]. 9304** 9305** The first argument must be the sqlite3_index_info object that is the 9306** first parameter to the xBestIndex() method. The second argument must be 9307** an index into the aConstraint[] array belonging to the sqlite3_index_info 9308** structure passed to xBestIndex. This function returns a pointer to a buffer 9309** containing the name of the collation sequence for the corresponding 9310** constraint. 9311*/ 9312SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 9313 9314/* 9315** CAPI3REF: Conflict resolution modes 9316** KEYWORDS: {conflict resolution mode} 9317** 9318** These constants are returned by [sqlite3_vtab_on_conflict()] to 9319** inform a [virtual table] implementation what the [ON CONFLICT] mode 9320** is for the SQL statement being evaluated. 9321** 9322** Note that the [SQLITE_IGNORE] constant is also used as a potential 9323** return value from the [sqlite3_set_authorizer()] callback and that 9324** [SQLITE_ABORT] is also a [result code]. 9325*/ 9326#define SQLITE_ROLLBACK 1 9327/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 9328#define SQLITE_FAIL 3 9329/* #define SQLITE_ABORT 4 // Also an error code */ 9330#define SQLITE_REPLACE 5 9331 9332/* 9333** CAPI3REF: Prepared Statement Scan Status Opcodes 9334** KEYWORDS: {scanstatus options} 9335** 9336** The following constants can be used for the T parameter to the 9337** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 9338** different metric for sqlite3_stmt_scanstatus() to return. 9339** 9340** When the value returned to V is a string, space to hold that string is 9341** managed by the prepared statement S and will be automatically freed when 9342** S is finalized. 9343** 9344** <dl> 9345** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 9346** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be 9347** set to the total number of times that the X-th loop has run.</dd> 9348** 9349** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 9350** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set 9351** to the total number of rows examined by all iterations of the X-th loop.</dd> 9352** 9353** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 9354** <dd>^The "double" variable pointed to by the V parameter will be set to the 9355** query planner's estimate for the average number of rows output from each 9356** iteration of the X-th loop. If the query planner's estimates was accurate, 9357** then this value will approximate the quotient NVISIT/NLOOP and the 9358** product of this value for all prior loops with the same SELECTID will 9359** be the NLOOP value for the current loop. 9360** 9361** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 9362** <dd>^The "const char *" variable pointed to by the V parameter will be set 9363** to a zero-terminated UTF-8 string containing the name of the index or table 9364** used for the X-th loop. 9365** 9366** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 9367** <dd>^The "const char *" variable pointed to by the V parameter will be set 9368** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 9369** description for the X-th loop. 9370** 9371** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 9372** <dd>^The "int" variable pointed to by the V parameter will be set to the 9373** "select-id" for the X-th loop. The select-id identifies which query or 9374** subquery the loop is part of. The main query has a select-id of zero. 9375** The select-id is the same value as is output in the first column 9376** of an [EXPLAIN QUERY PLAN] query. 9377** </dl> 9378*/ 9379#define SQLITE_SCANSTAT_NLOOP 0 9380#define SQLITE_SCANSTAT_NVISIT 1 9381#define SQLITE_SCANSTAT_EST 2 9382#define SQLITE_SCANSTAT_NAME 3 9383#define SQLITE_SCANSTAT_EXPLAIN 4 9384#define SQLITE_SCANSTAT_SELECTID 5 9385 9386/* 9387** CAPI3REF: Prepared Statement Scan Status 9388** METHOD: sqlite3_stmt 9389** 9390** This interface returns information about the predicted and measured 9391** performance for pStmt. Advanced applications can use this 9392** interface to compare the predicted and the measured performance and 9393** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 9394** 9395** Since this interface is expected to be rarely used, it is only 9396** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 9397** compile-time option. 9398** 9399** The "iScanStatusOp" parameter determines which status information to return. 9400** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 9401** of this interface is undefined. 9402** ^The requested measurement is written into a variable pointed to by 9403** the "pOut" parameter. 9404** Parameter "idx" identifies the specific loop to retrieve statistics for. 9405** Loops are numbered starting from zero. ^If idx is out of range - less than 9406** zero or greater than or equal to the total number of loops used to implement 9407** the statement - a non-zero value is returned and the variable that pOut 9408** points to is unchanged. 9409** 9410** ^Statistics might not be available for all loops in all statements. ^In cases 9411** where there exist loops with no available statistics, this function behaves 9412** as if the loop did not exist - it returns non-zero and leave the variable 9413** that pOut points to unchanged. 9414** 9415** See also: [sqlite3_stmt_scanstatus_reset()] 9416*/ 9417int sqlite3_stmt_scanstatus( 9418 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 9419 int idx, /* Index of loop to report on */ 9420 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 9421 void *pOut /* Result written here */ 9422); 9423 9424/* 9425** CAPI3REF: Zero Scan-Status Counters 9426** METHOD: sqlite3_stmt 9427** 9428** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 9429** 9430** This API is only available if the library is built with pre-processor 9431** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 9432*/ 9433void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 9434 9435/* 9436** CAPI3REF: Flush caches to disk mid-transaction 9437** METHOD: sqlite3 9438** 9439** ^If a write-transaction is open on [database connection] D when the 9440** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 9441** pages in the pager-cache that are not currently in use are written out 9442** to disk. A dirty page may be in use if a database cursor created by an 9443** active SQL statement is reading from it, or if it is page 1 of a database 9444** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 9445** interface flushes caches for all schemas - "main", "temp", and 9446** any [attached] databases. 9447** 9448** ^If this function needs to obtain extra database locks before dirty pages 9449** can be flushed to disk, it does so. ^If those locks cannot be obtained 9450** immediately and there is a busy-handler callback configured, it is invoked 9451** in the usual manner. ^If the required lock still cannot be obtained, then 9452** the database is skipped and an attempt made to flush any dirty pages 9453** belonging to the next (if any) database. ^If any databases are skipped 9454** because locks cannot be obtained, but no other error occurs, this 9455** function returns SQLITE_BUSY. 9456** 9457** ^If any other error occurs while flushing dirty pages to disk (for 9458** example an IO error or out-of-memory condition), then processing is 9459** abandoned and an SQLite [error code] is returned to the caller immediately. 9460** 9461** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 9462** 9463** ^This function does not set the database handle error code or message 9464** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 9465*/ 9466int sqlite3_db_cacheflush(sqlite3*); 9467 9468/* 9469** CAPI3REF: The pre-update hook. 9470** METHOD: sqlite3 9471** 9472** ^These interfaces are only available if SQLite is compiled using the 9473** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 9474** 9475** ^The [sqlite3_preupdate_hook()] interface registers a callback function 9476** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 9477** on a database table. 9478** ^At most one preupdate hook may be registered at a time on a single 9479** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 9480** the previous setting. 9481** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 9482** with a NULL pointer as the second parameter. 9483** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 9484** the first parameter to callbacks. 9485** 9486** ^The preupdate hook only fires for changes to real database tables; the 9487** preupdate hook is not invoked for changes to [virtual tables] or to 9488** system tables like sqlite_sequence or sqlite_stat1. 9489** 9490** ^The second parameter to the preupdate callback is a pointer to 9491** the [database connection] that registered the preupdate hook. 9492** ^The third parameter to the preupdate callback is one of the constants 9493** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 9494** kind of update operation that is about to occur. 9495** ^(The fourth parameter to the preupdate callback is the name of the 9496** database within the database connection that is being modified. This 9497** will be "main" for the main database or "temp" for TEMP tables or 9498** the name given after the AS keyword in the [ATTACH] statement for attached 9499** databases.)^ 9500** ^The fifth parameter to the preupdate callback is the name of the 9501** table that is being modified. 9502** 9503** For an UPDATE or DELETE operation on a [rowid table], the sixth 9504** parameter passed to the preupdate callback is the initial [rowid] of the 9505** row being modified or deleted. For an INSERT operation on a rowid table, 9506** or any operation on a WITHOUT ROWID table, the value of the sixth 9507** parameter is undefined. For an INSERT or UPDATE on a rowid table the 9508** seventh parameter is the final rowid value of the row being inserted 9509** or updated. The value of the seventh parameter passed to the callback 9510** function is not defined for operations on WITHOUT ROWID tables, or for 9511** DELETE operations on rowid tables. 9512** 9513** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 9514** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 9515** provide additional information about a preupdate event. These routines 9516** may only be called from within a preupdate callback. Invoking any of 9517** these routines from outside of a preupdate callback or with a 9518** [database connection] pointer that is different from the one supplied 9519** to the preupdate callback results in undefined and probably undesirable 9520** behavior. 9521** 9522** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 9523** in the row that is being inserted, updated, or deleted. 9524** 9525** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 9526** a [protected sqlite3_value] that contains the value of the Nth column of 9527** the table row before it is updated. The N parameter must be between 0 9528** and one less than the number of columns or the behavior will be 9529** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 9530** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 9531** behavior is undefined. The [sqlite3_value] that P points to 9532** will be destroyed when the preupdate callback returns. 9533** 9534** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 9535** a [protected sqlite3_value] that contains the value of the Nth column of 9536** the table row after it is updated. The N parameter must be between 0 9537** and one less than the number of columns or the behavior will be 9538** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 9539** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 9540** behavior is undefined. The [sqlite3_value] that P points to 9541** will be destroyed when the preupdate callback returns. 9542** 9543** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 9544** callback was invoked as a result of a direct insert, update, or delete 9545** operation; or 1 for inserts, updates, or deletes invoked by top-level 9546** triggers; or 2 for changes resulting from triggers called by top-level 9547** triggers; and so forth. 9548** 9549** See also: [sqlite3_update_hook()] 9550*/ 9551#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 9552void *sqlite3_preupdate_hook( 9553 sqlite3 *db, 9554 void(*xPreUpdate)( 9555 void *pCtx, /* Copy of third arg to preupdate_hook() */ 9556 sqlite3 *db, /* Database handle */ 9557 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 9558 char const *zDb, /* Database name */ 9559 char const *zName, /* Table name */ 9560 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 9561 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 9562 ), 9563 void* 9564); 9565int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 9566int sqlite3_preupdate_count(sqlite3 *); 9567int sqlite3_preupdate_depth(sqlite3 *); 9568int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 9569#endif 9570 9571/* 9572** CAPI3REF: Low-level system error code 9573** METHOD: sqlite3 9574** 9575** ^Attempt to return the underlying operating system error code or error 9576** number that caused the most recent I/O error or failure to open a file. 9577** The return value is OS-dependent. For example, on unix systems, after 9578** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 9579** called to get back the underlying "errno" that caused the problem, such 9580** as ENOSPC, EAUTH, EISDIR, and so forth. 9581*/ 9582int sqlite3_system_errno(sqlite3*); 9583 9584/* 9585** CAPI3REF: Database Snapshot 9586** KEYWORDS: {snapshot} {sqlite3_snapshot} 9587** 9588** An instance of the snapshot object records the state of a [WAL mode] 9589** database for some specific point in history. 9590** 9591** In [WAL mode], multiple [database connections] that are open on the 9592** same database file can each be reading a different historical version 9593** of the database file. When a [database connection] begins a read 9594** transaction, that connection sees an unchanging copy of the database 9595** as it existed for the point in time when the transaction first started. 9596** Subsequent changes to the database from other connections are not seen 9597** by the reader until a new read transaction is started. 9598** 9599** The sqlite3_snapshot object records state information about an historical 9600** version of the database file so that it is possible to later open a new read 9601** transaction that sees that historical version of the database rather than 9602** the most recent version. 9603*/ 9604typedef struct sqlite3_snapshot { 9605 unsigned char hidden[48]; 9606} sqlite3_snapshot; 9607 9608/* 9609** CAPI3REF: Record A Database Snapshot 9610** CONSTRUCTOR: sqlite3_snapshot 9611** 9612** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 9613** new [sqlite3_snapshot] object that records the current state of 9614** schema S in database connection D. ^On success, the 9615** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 9616** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 9617** If there is not already a read-transaction open on schema S when 9618** this function is called, one is opened automatically. 9619** 9620** The following must be true for this function to succeed. If any of 9621** the following statements are false when sqlite3_snapshot_get() is 9622** called, SQLITE_ERROR is returned. The final value of *P is undefined 9623** in this case. 9624** 9625** <ul> 9626** <li> The database handle must not be in [autocommit mode]. 9627** 9628** <li> Schema S of [database connection] D must be a [WAL mode] database. 9629** 9630** <li> There must not be a write transaction open on schema S of database 9631** connection D. 9632** 9633** <li> One or more transactions must have been written to the current wal 9634** file since it was created on disk (by any connection). This means 9635** that a snapshot cannot be taken on a wal mode database with no wal 9636** file immediately after it is first opened. At least one transaction 9637** must be written to it first. 9638** </ul> 9639** 9640** This function may also return SQLITE_NOMEM. If it is called with the 9641** database handle in autocommit mode but fails for some other reason, 9642** whether or not a read transaction is opened on schema S is undefined. 9643** 9644** The [sqlite3_snapshot] object returned from a successful call to 9645** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 9646** to avoid a memory leak. 9647** 9648** The [sqlite3_snapshot_get()] interface is only available when the 9649** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9650*/ 9651SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 9652 sqlite3 *db, 9653 const char *zSchema, 9654 sqlite3_snapshot **ppSnapshot 9655); 9656 9657/* 9658** CAPI3REF: Start a read transaction on an historical snapshot 9659** METHOD: sqlite3_snapshot 9660** 9661** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read 9662** transaction or upgrades an existing one for schema S of 9663** [database connection] D such that the read transaction refers to 9664** historical [snapshot] P, rather than the most recent change to the 9665** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK 9666** on success or an appropriate [error code] if it fails. 9667** 9668** ^In order to succeed, the database connection must not be in 9669** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there 9670** is already a read transaction open on schema S, then the database handle 9671** must have no active statements (SELECT statements that have been passed 9672** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()). 9673** SQLITE_ERROR is returned if either of these conditions is violated, or 9674** if schema S does not exist, or if the snapshot object is invalid. 9675** 9676** ^A call to sqlite3_snapshot_open() will fail to open if the specified 9677** snapshot has been overwritten by a [checkpoint]. In this case 9678** SQLITE_ERROR_SNAPSHOT is returned. 9679** 9680** If there is already a read transaction open when this function is 9681** invoked, then the same read transaction remains open (on the same 9682** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT 9683** is returned. If another error code - for example SQLITE_PROTOCOL or an 9684** SQLITE_IOERR error code - is returned, then the final state of the 9685** read transaction is undefined. If SQLITE_OK is returned, then the 9686** read transaction is now open on database snapshot P. 9687** 9688** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 9689** database connection D does not know that the database file for 9690** schema S is in [WAL mode]. A database connection might not know 9691** that the database file is in [WAL mode] if there has been no prior 9692** I/O on that database connection, or if the database entered [WAL mode] 9693** after the most recent I/O on the database connection.)^ 9694** (Hint: Run "[PRAGMA application_id]" against a newly opened 9695** database connection in order to make it ready to use snapshots.) 9696** 9697** The [sqlite3_snapshot_open()] interface is only available when the 9698** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9699*/ 9700SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 9701 sqlite3 *db, 9702 const char *zSchema, 9703 sqlite3_snapshot *pSnapshot 9704); 9705 9706/* 9707** CAPI3REF: Destroy a snapshot 9708** DESTRUCTOR: sqlite3_snapshot 9709** 9710** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 9711** The application must eventually free every [sqlite3_snapshot] object 9712** using this routine to avoid a memory leak. 9713** 9714** The [sqlite3_snapshot_free()] interface is only available when the 9715** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9716*/ 9717SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 9718 9719/* 9720** CAPI3REF: Compare the ages of two snapshot handles. 9721** METHOD: sqlite3_snapshot 9722** 9723** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 9724** of two valid snapshot handles. 9725** 9726** If the two snapshot handles are not associated with the same database 9727** file, the result of the comparison is undefined. 9728** 9729** Additionally, the result of the comparison is only valid if both of the 9730** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 9731** last time the wal file was deleted. The wal file is deleted when the 9732** database is changed back to rollback mode or when the number of database 9733** clients drops to zero. If either snapshot handle was obtained before the 9734** wal file was last deleted, the value returned by this function 9735** is undefined. 9736** 9737** Otherwise, this API returns a negative value if P1 refers to an older 9738** snapshot than P2, zero if the two handles refer to the same database 9739** snapshot, and a positive value if P1 is a newer snapshot than P2. 9740** 9741** This interface is only available if SQLite is compiled with the 9742** [SQLITE_ENABLE_SNAPSHOT] option. 9743*/ 9744SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 9745 sqlite3_snapshot *p1, 9746 sqlite3_snapshot *p2 9747); 9748 9749/* 9750** CAPI3REF: Recover snapshots from a wal file 9751** METHOD: sqlite3_snapshot 9752** 9753** If a [WAL file] remains on disk after all database connections close 9754** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control] 9755** or because the last process to have the database opened exited without 9756** calling [sqlite3_close()]) and a new connection is subsequently opened 9757** on that database and [WAL file], the [sqlite3_snapshot_open()] interface 9758** will only be able to open the last transaction added to the WAL file 9759** even though the WAL file contains other valid transactions. 9760** 9761** This function attempts to scan the WAL file associated with database zDb 9762** of database handle db and make all valid snapshots available to 9763** sqlite3_snapshot_open(). It is an error if there is already a read 9764** transaction open on the database, or if the database is not a WAL mode 9765** database. 9766** 9767** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 9768** 9769** This interface is only available if SQLite is compiled with the 9770** [SQLITE_ENABLE_SNAPSHOT] option. 9771*/ 9772SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 9773 9774/* 9775** CAPI3REF: Serialize a database 9776** 9777** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 9778** that is a serialization of the S database on [database connection] D. 9779** If P is not a NULL pointer, then the size of the database in bytes 9780** is written into *P. 9781** 9782** For an ordinary on-disk database file, the serialization is just a 9783** copy of the disk file. For an in-memory database or a "TEMP" database, 9784** the serialization is the same sequence of bytes which would be written 9785** to disk if that database where backed up to disk. 9786** 9787** The usual case is that sqlite3_serialize() copies the serialization of 9788** the database into memory obtained from [sqlite3_malloc64()] and returns 9789** a pointer to that memory. The caller is responsible for freeing the 9790** returned value to avoid a memory leak. However, if the F argument 9791** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 9792** are made, and the sqlite3_serialize() function will return a pointer 9793** to the contiguous memory representation of the database that SQLite 9794** is currently using for that database, or NULL if the no such contiguous 9795** memory representation of the database exists. A contiguous memory 9796** representation of the database will usually only exist if there has 9797** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 9798** values of D and S. 9799** The size of the database is written into *P even if the 9800** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy 9801** of the database exists. 9802** 9803** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 9804** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 9805** allocation error occurs. 9806** 9807** This interface is only available if SQLite is compiled with the 9808** [SQLITE_ENABLE_DESERIALIZE] option. 9809*/ 9810unsigned char *sqlite3_serialize( 9811 sqlite3 *db, /* The database connection */ 9812 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 9813 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 9814 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 9815); 9816 9817/* 9818** CAPI3REF: Flags for sqlite3_serialize 9819** 9820** Zero or more of the following constants can be OR-ed together for 9821** the F argument to [sqlite3_serialize(D,S,P,F)]. 9822** 9823** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 9824** a pointer to contiguous in-memory database that it is currently using, 9825** without making a copy of the database. If SQLite is not currently using 9826** a contiguous in-memory database, then this option causes 9827** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 9828** using a contiguous in-memory database if it has been initialized by a 9829** prior call to [sqlite3_deserialize()]. 9830*/ 9831#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 9832 9833/* 9834** CAPI3REF: Deserialize a database 9835** 9836** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 9837** [database connection] D to disconnect from database S and then 9838** reopen S as an in-memory database based on the serialization contained 9839** in P. The serialized database P is N bytes in size. M is the size of 9840** the buffer P, which might be larger than N. If M is larger than N, and 9841** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 9842** permitted to add content to the in-memory database as long as the total 9843** size does not exceed M bytes. 9844** 9845** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 9846** invoke sqlite3_free() on the serialization buffer when the database 9847** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 9848** SQLite will try to increase the buffer size using sqlite3_realloc64() 9849** if writes on the database cause it to grow larger than M bytes. 9850** 9851** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 9852** database is currently in a read transaction or is involved in a backup 9853** operation. 9854** 9855** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 9856** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 9857** [sqlite3_free()] is invoked on argument P prior to returning. 9858** 9859** This interface is only available if SQLite is compiled with the 9860** [SQLITE_ENABLE_DESERIALIZE] option. 9861*/ 9862int sqlite3_deserialize( 9863 sqlite3 *db, /* The database connection */ 9864 const char *zSchema, /* Which DB to reopen with the deserialization */ 9865 unsigned char *pData, /* The serialized database content */ 9866 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 9867 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 9868 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 9869); 9870 9871/* 9872** CAPI3REF: Flags for sqlite3_deserialize() 9873** 9874** The following are allowed values for 6th argument (the F argument) to 9875** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 9876** 9877** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 9878** in the P argument is held in memory obtained from [sqlite3_malloc64()] 9879** and that SQLite should take ownership of this memory and automatically 9880** free it when it has finished using it. Without this flag, the caller 9881** is responsible for freeing any dynamically allocated memory. 9882** 9883** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 9884** grow the size of the database using calls to [sqlite3_realloc64()]. This 9885** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 9886** Without this flag, the deserialized database cannot increase in size beyond 9887** the number of bytes specified by the M parameter. 9888** 9889** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 9890** should be treated as read-only. 9891*/ 9892#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 9893#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 9894#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 9895 9896/* 9897** Undo the hack that converts floating point types to integer for 9898** builds on processors without floating point support. 9899*/ 9900#ifdef SQLITE_OMIT_FLOATING_POINT 9901# undef double 9902#endif 9903 9904#ifdef __cplusplus 9905} /* End of the 'extern "C"' block */ 9906#endif 9907#endif /* SQLITE3_H */ 9908