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_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 508#define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8)) 509#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 510#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 511#define SQLITE_BUSY_TIMEOUT (SQLITE_BUSY | (3<<8)) 512#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 513#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 514#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 515#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 516#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */ 517#define SQLITE_CANTOPEN_SYMLINK (SQLITE_CANTOPEN | (6<<8)) 518#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 519#define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8)) 520#define SQLITE_CORRUPT_INDEX (SQLITE_CORRUPT | (3<<8)) 521#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 522#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 523#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 524#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 525#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8)) 526#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8)) 527#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 528#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 529#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 530#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 531#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 532#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 533#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 534#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 535#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 536#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 537#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 538#define SQLITE_CONSTRAINT_PINNED (SQLITE_CONSTRAINT |(11<<8)) 539#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 540#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 541#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 542#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 543#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 544#define SQLITE_OK_SYMLINK (SQLITE_OK | (2<<8)) 545 546/* 547** CAPI3REF: Flags For File Open Operations 548** 549** These bit values are intended for use in the 550** 3rd parameter to the [sqlite3_open_v2()] interface and 551** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 552*/ 553#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 554#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 555#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 556#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 557#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 558#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 559#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 560#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 561#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 562#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 563#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 564#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 565#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 566#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 567#define SQLITE_OPEN_SUPER_JOURNAL 0x00004000 /* VFS only */ 568#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 569#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 570#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 571#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 572#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 573#define SQLITE_OPEN_NOFOLLOW 0x01000000 /* Ok for sqlite3_open_v2() */ 574 575/* Reserved: 0x00F00000 */ 576/* Legacy compatibility: */ 577#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 578 579 580/* 581** CAPI3REF: Device Characteristics 582** 583** The xDeviceCharacteristics method of the [sqlite3_io_methods] 584** object returns an integer which is a vector of these 585** bit values expressing I/O characteristics of the mass storage 586** device that holds the file that the [sqlite3_io_methods] 587** refers to. 588** 589** The SQLITE_IOCAP_ATOMIC property means that all writes of 590** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 591** mean that writes of blocks that are nnn bytes in size and 592** are aligned to an address which is an integer multiple of 593** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 594** that when data is appended to a file, the data is appended 595** first then the size of the file is extended, never the other 596** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 597** information is written to disk in the same order as calls 598** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 599** after reboot following a crash or power loss, the only bytes in a 600** file that were written at the application level might have changed 601** and that adjacent bytes, even bytes within the same sector are 602** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 603** flag indicates that a file cannot be deleted when open. The 604** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 605** read-only media and cannot be changed even by processes with 606** elevated privileges. 607** 608** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 609** filesystem supports doing multiple write operations atomically when those 610** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 611** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 612*/ 613#define SQLITE_IOCAP_ATOMIC 0x00000001 614#define SQLITE_IOCAP_ATOMIC512 0x00000002 615#define SQLITE_IOCAP_ATOMIC1K 0x00000004 616#define SQLITE_IOCAP_ATOMIC2K 0x00000008 617#define SQLITE_IOCAP_ATOMIC4K 0x00000010 618#define SQLITE_IOCAP_ATOMIC8K 0x00000020 619#define SQLITE_IOCAP_ATOMIC16K 0x00000040 620#define SQLITE_IOCAP_ATOMIC32K 0x00000080 621#define SQLITE_IOCAP_ATOMIC64K 0x00000100 622#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 623#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 624#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 625#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 626#define SQLITE_IOCAP_IMMUTABLE 0x00002000 627#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 628 629/* 630** CAPI3REF: File Locking Levels 631** 632** SQLite uses one of these integer values as the second 633** argument to calls it makes to the xLock() and xUnlock() methods 634** of an [sqlite3_io_methods] object. 635*/ 636#define SQLITE_LOCK_NONE 0 637#define SQLITE_LOCK_SHARED 1 638#define SQLITE_LOCK_RESERVED 2 639#define SQLITE_LOCK_PENDING 3 640#define SQLITE_LOCK_EXCLUSIVE 4 641 642/* 643** CAPI3REF: Synchronization Type Flags 644** 645** When SQLite invokes the xSync() method of an 646** [sqlite3_io_methods] object it uses a combination of 647** these integer values as the second argument. 648** 649** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 650** sync operation only needs to flush data to mass storage. Inode 651** information need not be flushed. If the lower four bits of the flag 652** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 653** If the lower four bits equal SQLITE_SYNC_FULL, that means 654** to use Mac OS X style fullsync instead of fsync(). 655** 656** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 657** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 658** settings. The [synchronous pragma] determines when calls to the 659** xSync VFS method occur and applies uniformly across all platforms. 660** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 661** energetic or rigorous or forceful the sync operations are and 662** only make a difference on Mac OSX for the default SQLite code. 663** (Third-party VFS implementations might also make the distinction 664** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 665** operating systems natively supported by SQLite, only Mac OSX 666** cares about the difference.) 667*/ 668#define SQLITE_SYNC_NORMAL 0x00002 669#define SQLITE_SYNC_FULL 0x00003 670#define SQLITE_SYNC_DATAONLY 0x00010 671 672/* 673** CAPI3REF: OS Interface Open File Handle 674** 675** An [sqlite3_file] object represents an open file in the 676** [sqlite3_vfs | OS interface layer]. Individual OS interface 677** implementations will 678** want to subclass this object by appending additional fields 679** for their own use. The pMethods entry is a pointer to an 680** [sqlite3_io_methods] object that defines methods for performing 681** I/O operations on the open file. 682*/ 683typedef struct sqlite3_file sqlite3_file; 684struct sqlite3_file { 685 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 686}; 687 688/* 689** CAPI3REF: OS Interface File Virtual Methods Object 690** 691** Every file opened by the [sqlite3_vfs.xOpen] method populates an 692** [sqlite3_file] object (or, more commonly, a subclass of the 693** [sqlite3_file] object) with a pointer to an instance of this object. 694** This object defines the methods used to perform various operations 695** against the open file represented by the [sqlite3_file] object. 696** 697** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 698** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 699** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 700** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 701** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 702** to NULL. 703** 704** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 705** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 706** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 707** flag may be ORed in to indicate that only the data of the file 708** and not its inode needs to be synced. 709** 710** The integer values to xLock() and xUnlock() are one of 711** <ul> 712** <li> [SQLITE_LOCK_NONE], 713** <li> [SQLITE_LOCK_SHARED], 714** <li> [SQLITE_LOCK_RESERVED], 715** <li> [SQLITE_LOCK_PENDING], or 716** <li> [SQLITE_LOCK_EXCLUSIVE]. 717** </ul> 718** xLock() increases the lock. xUnlock() decreases the lock. 719** The xCheckReservedLock() method checks whether any database connection, 720** either in this process or in some other process, is holding a RESERVED, 721** PENDING, or EXCLUSIVE lock on the file. It returns true 722** if such a lock exists and false otherwise. 723** 724** The xFileControl() method is a generic interface that allows custom 725** VFS implementations to directly control an open file using the 726** [sqlite3_file_control()] interface. The second "op" argument is an 727** integer opcode. The third argument is a generic pointer intended to 728** point to a structure that may contain arguments or space in which to 729** write return values. Potential uses for xFileControl() might be 730** functions to enable blocking locks with timeouts, to change the 731** locking strategy (for example to use dot-file locks), to inquire 732** about the status of a lock, or to break stale locks. The SQLite 733** core reserves all opcodes less than 100 for its own use. 734** A [file control opcodes | list of opcodes] less than 100 is available. 735** Applications that define a custom xFileControl method should use opcodes 736** greater than 100 to avoid conflicts. VFS implementations should 737** return [SQLITE_NOTFOUND] for file control opcodes that they do not 738** recognize. 739** 740** The xSectorSize() method returns the sector size of the 741** device that underlies the file. The sector size is the 742** minimum write that can be performed without disturbing 743** other bytes in the file. The xDeviceCharacteristics() 744** method returns a bit vector describing behaviors of the 745** underlying device: 746** 747** <ul> 748** <li> [SQLITE_IOCAP_ATOMIC] 749** <li> [SQLITE_IOCAP_ATOMIC512] 750** <li> [SQLITE_IOCAP_ATOMIC1K] 751** <li> [SQLITE_IOCAP_ATOMIC2K] 752** <li> [SQLITE_IOCAP_ATOMIC4K] 753** <li> [SQLITE_IOCAP_ATOMIC8K] 754** <li> [SQLITE_IOCAP_ATOMIC16K] 755** <li> [SQLITE_IOCAP_ATOMIC32K] 756** <li> [SQLITE_IOCAP_ATOMIC64K] 757** <li> [SQLITE_IOCAP_SAFE_APPEND] 758** <li> [SQLITE_IOCAP_SEQUENTIAL] 759** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 760** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 761** <li> [SQLITE_IOCAP_IMMUTABLE] 762** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 763** </ul> 764** 765** The SQLITE_IOCAP_ATOMIC property means that all writes of 766** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 767** mean that writes of blocks that are nnn bytes in size and 768** are aligned to an address which is an integer multiple of 769** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 770** that when data is appended to a file, the data is appended 771** first then the size of the file is extended, never the other 772** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 773** information is written to disk in the same order as calls 774** to xWrite(). 775** 776** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 777** in the unread portions of the buffer with zeros. A VFS that 778** fails to zero-fill short reads might seem to work. However, 779** failure to zero-fill short reads will eventually lead to 780** database corruption. 781*/ 782typedef struct sqlite3_io_methods sqlite3_io_methods; 783struct sqlite3_io_methods { 784 int iVersion; 785 int (*xClose)(sqlite3_file*); 786 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 787 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 788 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 789 int (*xSync)(sqlite3_file*, int flags); 790 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 791 int (*xLock)(sqlite3_file*, int); 792 int (*xUnlock)(sqlite3_file*, int); 793 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 794 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 795 int (*xSectorSize)(sqlite3_file*); 796 int (*xDeviceCharacteristics)(sqlite3_file*); 797 /* Methods above are valid for version 1 */ 798 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 799 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 800 void (*xShmBarrier)(sqlite3_file*); 801 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 802 /* Methods above are valid for version 2 */ 803 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 804 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 805 /* Methods above are valid for version 3 */ 806 /* Additional methods may be added in future releases */ 807}; 808 809/* 810** CAPI3REF: Standard File Control Opcodes 811** KEYWORDS: {file control opcodes} {file control opcode} 812** 813** These integer constants are opcodes for the xFileControl method 814** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 815** interface. 816** 817** <ul> 818** <li>[[SQLITE_FCNTL_LOCKSTATE]] 819** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 820** opcode causes the xFileControl method to write the current state of 821** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 822** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 823** into an integer that the pArg argument points to. This capability 824** is used during testing and is only available when the SQLITE_TEST 825** compile-time option is used. 826** 827** <li>[[SQLITE_FCNTL_SIZE_HINT]] 828** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 829** layer a hint of how large the database file will grow to be during the 830** current transaction. This hint is not guaranteed to be accurate but it 831** is often close. The underlying VFS might choose to preallocate database 832** file space based on this hint in order to help writes to the database 833** file run faster. 834** 835** <li>[[SQLITE_FCNTL_SIZE_LIMIT]] 836** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that 837** implements [sqlite3_deserialize()] to set an upper bound on the size 838** of the in-memory database. The argument is a pointer to a [sqlite3_int64]. 839** If the integer pointed to is negative, then it is filled in with the 840** current limit. Otherwise the limit is set to the larger of the value 841** of the integer pointed to and the current database size. The integer 842** pointed to is set to the new limit. 843** 844** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 845** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 846** extends and truncates the database file in chunks of a size specified 847** by the user. The fourth argument to [sqlite3_file_control()] should 848** point to an integer (type int) containing the new chunk-size to use 849** for the nominated database. Allocating database file space in large 850** chunks (say 1MB at a time), may reduce file-system fragmentation and 851** improve performance on some systems. 852** 853** <li>[[SQLITE_FCNTL_FILE_POINTER]] 854** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 855** to the [sqlite3_file] object associated with a particular database 856** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 857** 858** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 859** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 860** to the [sqlite3_file] object associated with the journal file (either 861** the [rollback journal] or the [write-ahead log]) for a particular database 862** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 863** 864** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 865** No longer in use. 866** 867** <li>[[SQLITE_FCNTL_SYNC]] 868** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 869** sent to the VFS immediately before the xSync method is invoked on a 870** database file descriptor. Or, if the xSync method is not invoked 871** because the user has configured SQLite with 872** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 873** of the xSync method. In most cases, the pointer argument passed with 874** this file-control is NULL. However, if the database file is being synced 875** as part of a multi-database commit, the argument points to a nul-terminated 876** string containing the transactions super-journal file name. VFSes that 877** do not need this signal should silently ignore this opcode. Applications 878** should not call [sqlite3_file_control()] with this opcode as doing so may 879** disrupt the operation of the specialized VFSes that do require it. 880** 881** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 882** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 883** and sent to the VFS after a transaction has been committed immediately 884** but before the database is unlocked. VFSes that do not need this signal 885** should silently ignore this opcode. Applications should not call 886** [sqlite3_file_control()] with this opcode as doing so may disrupt the 887** operation of the specialized VFSes that do require it. 888** 889** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 890** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 891** retry counts and intervals for certain disk I/O operations for the 892** windows [VFS] in order to provide robustness in the presence of 893** anti-virus programs. By default, the windows VFS will retry file read, 894** file write, and file delete operations up to 10 times, with a delay 895** of 25 milliseconds before the first retry and with the delay increasing 896** by an additional 25 milliseconds with each subsequent retry. This 897** opcode allows these two values (10 retries and 25 milliseconds of delay) 898** to be adjusted. The values are changed for all database connections 899** within the same process. The argument is a pointer to an array of two 900** integers where the first integer is the new retry count and the second 901** integer is the delay. If either integer is negative, then the setting 902** is not changed but instead the prior value of that setting is written 903** into the array entry, allowing the current retry settings to be 904** interrogated. The zDbName parameter is ignored. 905** 906** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 907** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 908** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 909** write ahead log ([WAL file]) and shared memory 910** files used for transaction control 911** are automatically deleted when the latest connection to the database 912** closes. Setting persistent WAL mode causes those files to persist after 913** close. Persisting the files is useful when other processes that do not 914** have write permission on the directory containing the database file want 915** to read the database file, as the WAL and shared memory files must exist 916** in order for the database to be readable. The fourth parameter to 917** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 918** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 919** WAL mode. If the integer is -1, then it is overwritten with the current 920** WAL persistence setting. 921** 922** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 923** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 924** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 925** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 926** xDeviceCharacteristics methods. The fourth parameter to 927** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 928** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 929** mode. If the integer is -1, then it is overwritten with the current 930** zero-damage mode setting. 931** 932** <li>[[SQLITE_FCNTL_OVERWRITE]] 933** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 934** a write transaction to indicate that, unless it is rolled back for some 935** reason, the entire database file will be overwritten by the current 936** transaction. This is used by VACUUM operations. 937** 938** <li>[[SQLITE_FCNTL_VFSNAME]] 939** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 940** all [VFSes] in the VFS stack. The names are of all VFS shims and the 941** final bottom-level VFS are written into memory obtained from 942** [sqlite3_malloc()] and the result is stored in the char* variable 943** that the fourth parameter of [sqlite3_file_control()] points to. 944** The caller is responsible for freeing the memory when done. As with 945** all file-control actions, there is no guarantee that this will actually 946** do anything. Callers should initialize the char* variable to a NULL 947** pointer in case this file-control is not implemented. This file-control 948** is intended for diagnostic use only. 949** 950** <li>[[SQLITE_FCNTL_VFS_POINTER]] 951** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 952** [VFSes] currently in use. ^(The argument X in 953** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 954** of type "[sqlite3_vfs] **". This opcodes will set *X 955** to a pointer to the top-level VFS.)^ 956** ^When there are multiple VFS shims in the stack, this opcode finds the 957** upper-most shim only. 958** 959** <li>[[SQLITE_FCNTL_PRAGMA]] 960** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 961** file control is sent to the open [sqlite3_file] object corresponding 962** to the database file to which the pragma statement refers. ^The argument 963** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 964** pointers to strings (char**) in which the second element of the array 965** is the name of the pragma and the third element is the argument to the 966** pragma or NULL if the pragma has no argument. ^The handler for an 967** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 968** of the char** argument point to a string obtained from [sqlite3_mprintf()] 969** or the equivalent and that string will become the result of the pragma or 970** the error message if the pragma fails. ^If the 971** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 972** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 973** file control returns [SQLITE_OK], then the parser assumes that the 974** VFS has handled the PRAGMA itself and the parser generates a no-op 975** prepared statement if result string is NULL, or that returns a copy 976** of the result string if the string is non-NULL. 977** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 978** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 979** that the VFS encountered an error while handling the [PRAGMA] and the 980** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 981** file control occurs at the beginning of pragma statement analysis and so 982** it is able to override built-in [PRAGMA] statements. 983** 984** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 985** ^The [SQLITE_FCNTL_BUSYHANDLER] 986** file-control may be invoked by SQLite on the database file handle 987** shortly after it is opened in order to provide a custom VFS with access 988** to the connection's busy-handler callback. The argument is of type (void**) 989** - an array of two (void *) values. The first (void *) actually points 990** to a function of type (int (*)(void *)). In order to invoke the connection's 991** busy-handler, this function should be invoked with the second (void *) in 992** the array as the only argument. If it returns non-zero, then the operation 993** should be retried. If it returns zero, the custom VFS should abandon the 994** current operation. 995** 996** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 997** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 998** to have SQLite generate a 999** temporary filename using the same algorithm that is followed to generate 1000** temporary filenames for TEMP tables and other internal uses. The 1001** argument should be a char** which will be filled with the filename 1002** written into memory obtained from [sqlite3_malloc()]. The caller should 1003** invoke [sqlite3_free()] on the result to avoid a memory leak. 1004** 1005** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 1006** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 1007** maximum number of bytes that will be used for memory-mapped I/O. 1008** The argument is a pointer to a value of type sqlite3_int64 that 1009** is an advisory maximum number of bytes in the file to memory map. The 1010** pointer is overwritten with the old value. The limit is not changed if 1011** the value originally pointed to is negative, and so the current limit 1012** can be queried by passing in a pointer to a negative number. This 1013** file-control is used internally to implement [PRAGMA mmap_size]. 1014** 1015** <li>[[SQLITE_FCNTL_TRACE]] 1016** The [SQLITE_FCNTL_TRACE] file control provides advisory information 1017** to the VFS about what the higher layers of the SQLite stack are doing. 1018** This file control is used by some VFS activity tracing [shims]. 1019** The argument is a zero-terminated string. Higher layers in the 1020** SQLite stack may generate instances of this file control if 1021** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 1022** 1023** <li>[[SQLITE_FCNTL_HAS_MOVED]] 1024** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 1025** pointer to an integer and it writes a boolean into that integer depending 1026** on whether or not the file has been renamed, moved, or deleted since it 1027** was first opened. 1028** 1029** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1030** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1031** underlying native file handle associated with a file handle. This file 1032** control interprets its argument as a pointer to a native file handle and 1033** writes the resulting value there. 1034** 1035** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1036** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1037** opcode causes the xFileControl method to swap the file handle with the one 1038** pointed to by the pArg argument. This capability is used during testing 1039** and only needs to be supported when SQLITE_TEST is defined. 1040** 1041** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1042** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1043** be advantageous to block on the next WAL lock if the lock is not immediately 1044** available. The WAL subsystem issues this signal during rare 1045** circumstances in order to fix a problem with priority inversion. 1046** Applications should <em>not</em> use this file-control. 1047** 1048** <li>[[SQLITE_FCNTL_ZIPVFS]] 1049** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1050** VFS should return SQLITE_NOTFOUND for this opcode. 1051** 1052** <li>[[SQLITE_FCNTL_RBU]] 1053** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1054** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1055** this opcode. 1056** 1057** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1058** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1059** the file descriptor is placed in "batch write mode", which 1060** means all subsequent write operations will be deferred and done 1061** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1062** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1063** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1064** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1065** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1066** no VFS interface calls on the same [sqlite3_file] file descriptor 1067** except for calls to the xWrite method and the xFileControl method 1068** with [SQLITE_FCNTL_SIZE_HINT]. 1069** 1070** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1071** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1072** operations since the previous successful call to 1073** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1074** This file control returns [SQLITE_OK] if and only if the writes were 1075** all performed successfully and have been committed to persistent storage. 1076** ^Regardless of whether or not it is successful, this file control takes 1077** the file descriptor out of batch write mode so that all subsequent 1078** write operations are independent. 1079** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1080** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1081** 1082** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1083** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1084** operations since the previous successful call to 1085** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1086** ^This file control takes the file descriptor out of batch write mode 1087** so that all subsequent write operations are independent. 1088** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1089** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1090** 1091** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]] 1092** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS 1093** to block for up to M milliseconds before failing when attempting to 1094** obtain a file lock using the xLock or xShmLock methods of the VFS. 1095** The parameter is a pointer to a 32-bit signed integer that contains 1096** the value that M is to be set to. Before returning, the 32-bit signed 1097** integer is overwritten with the previous value of M. 1098** 1099** <li>[[SQLITE_FCNTL_DATA_VERSION]] 1100** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to 1101** a database file. The argument is a pointer to a 32-bit unsigned integer. 1102** The "data version" for the pager is written into the pointer. The 1103** "data version" changes whenever any change occurs to the corresponding 1104** database file, either through SQL statements on the same database 1105** connection or through transactions committed by separate database 1106** connections possibly in other processes. The [sqlite3_total_changes()] 1107** interface can be used to find if any database on the connection has changed, 1108** but that interface responds to changes on TEMP as well as MAIN and does 1109** not provide a mechanism to detect changes to MAIN only. Also, the 1110** [sqlite3_total_changes()] interface responds to internal changes only and 1111** omits changes made by other database connections. The 1112** [PRAGMA data_version] command provides a mechanism to detect changes to 1113** a single attached database that occur due to other database connections, 1114** but omits changes implemented by the database connection on which it is 1115** called. This file control is the only mechanism to detect changes that 1116** happen either internally or externally and that are associated with 1117** a particular attached database. 1118** 1119** <li>[[SQLITE_FCNTL_CKPT_START]] 1120** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint 1121** in wal mode before the client starts to copy pages from the wal 1122** file to the database file. 1123** 1124** <li>[[SQLITE_FCNTL_CKPT_DONE]] 1125** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint 1126** in wal mode after the client has finished copying pages from the wal 1127** file to the database file, but before the *-shm file is updated to 1128** record the fact that the pages have been checkpointed. 1129** </ul> 1130*/ 1131#define SQLITE_FCNTL_LOCKSTATE 1 1132#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1133#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1134#define SQLITE_FCNTL_LAST_ERRNO 4 1135#define SQLITE_FCNTL_SIZE_HINT 5 1136#define SQLITE_FCNTL_CHUNK_SIZE 6 1137#define SQLITE_FCNTL_FILE_POINTER 7 1138#define SQLITE_FCNTL_SYNC_OMITTED 8 1139#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1140#define SQLITE_FCNTL_PERSIST_WAL 10 1141#define SQLITE_FCNTL_OVERWRITE 11 1142#define SQLITE_FCNTL_VFSNAME 12 1143#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1144#define SQLITE_FCNTL_PRAGMA 14 1145#define SQLITE_FCNTL_BUSYHANDLER 15 1146#define SQLITE_FCNTL_TEMPFILENAME 16 1147#define SQLITE_FCNTL_MMAP_SIZE 18 1148#define SQLITE_FCNTL_TRACE 19 1149#define SQLITE_FCNTL_HAS_MOVED 20 1150#define SQLITE_FCNTL_SYNC 21 1151#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1152#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1153#define SQLITE_FCNTL_WAL_BLOCK 24 1154#define SQLITE_FCNTL_ZIPVFS 25 1155#define SQLITE_FCNTL_RBU 26 1156#define SQLITE_FCNTL_VFS_POINTER 27 1157#define SQLITE_FCNTL_JOURNAL_POINTER 28 1158#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1159#define SQLITE_FCNTL_PDB 30 1160#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1161#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1162#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1163#define SQLITE_FCNTL_LOCK_TIMEOUT 34 1164#define SQLITE_FCNTL_DATA_VERSION 35 1165#define SQLITE_FCNTL_SIZE_LIMIT 36 1166#define SQLITE_FCNTL_CKPT_DONE 37 1167#define SQLITE_FCNTL_RESERVE_BYTES 38 1168#define SQLITE_FCNTL_CKPT_START 39 1169 1170/* deprecated names */ 1171#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1172#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1173#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1174 1175 1176/* 1177** CAPI3REF: Mutex Handle 1178** 1179** The mutex module within SQLite defines [sqlite3_mutex] to be an 1180** abstract type for a mutex object. The SQLite core never looks 1181** at the internal representation of an [sqlite3_mutex]. It only 1182** deals with pointers to the [sqlite3_mutex] object. 1183** 1184** Mutexes are created using [sqlite3_mutex_alloc()]. 1185*/ 1186typedef struct sqlite3_mutex sqlite3_mutex; 1187 1188/* 1189** CAPI3REF: Loadable Extension Thunk 1190** 1191** A pointer to the opaque sqlite3_api_routines structure is passed as 1192** the third parameter to entry points of [loadable extensions]. This 1193** structure must be typedefed in order to work around compiler warnings 1194** on some platforms. 1195*/ 1196typedef struct sqlite3_api_routines sqlite3_api_routines; 1197 1198/* 1199** CAPI3REF: OS Interface Object 1200** 1201** An instance of the sqlite3_vfs object defines the interface between 1202** the SQLite core and the underlying operating system. The "vfs" 1203** in the name of the object stands for "virtual file system". See 1204** the [VFS | VFS documentation] for further information. 1205** 1206** The VFS interface is sometimes extended by adding new methods onto 1207** the end. Each time such an extension occurs, the iVersion field 1208** is incremented. The iVersion value started out as 1 in 1209** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1210** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1211** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1212** may be appended to the sqlite3_vfs object and the iVersion value 1213** may increase again in future versions of SQLite. 1214** Note that due to an oversight, the structure 1215** of the sqlite3_vfs object changed in the transition from 1216** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1217** and yet the iVersion field was not increased. 1218** 1219** The szOsFile field is the size of the subclassed [sqlite3_file] 1220** structure used by this VFS. mxPathname is the maximum length of 1221** a pathname in this VFS. 1222** 1223** Registered sqlite3_vfs objects are kept on a linked list formed by 1224** the pNext pointer. The [sqlite3_vfs_register()] 1225** and [sqlite3_vfs_unregister()] interfaces manage this list 1226** in a thread-safe way. The [sqlite3_vfs_find()] interface 1227** searches the list. Neither the application code nor the VFS 1228** implementation should use the pNext pointer. 1229** 1230** The pNext field is the only field in the sqlite3_vfs 1231** structure that SQLite will ever modify. SQLite will only access 1232** or modify this field while holding a particular static mutex. 1233** The application should never modify anything within the sqlite3_vfs 1234** object once the object has been registered. 1235** 1236** The zName field holds the name of the VFS module. The name must 1237** be unique across all VFS modules. 1238** 1239** [[sqlite3_vfs.xOpen]] 1240** ^SQLite guarantees that the zFilename parameter to xOpen 1241** is either a NULL pointer or string obtained 1242** from xFullPathname() with an optional suffix added. 1243** ^If a suffix is added to the zFilename parameter, it will 1244** consist of a single "-" character followed by no more than 1245** 11 alphanumeric and/or "-" characters. 1246** ^SQLite further guarantees that 1247** the string will be valid and unchanged until xClose() is 1248** called. Because of the previous sentence, 1249** the [sqlite3_file] can safely store a pointer to the 1250** filename if it needs to remember the filename for some reason. 1251** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1252** must invent its own temporary name for the file. ^Whenever the 1253** xFilename parameter is NULL it will also be the case that the 1254** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1255** 1256** The flags argument to xOpen() includes all bits set in 1257** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1258** or [sqlite3_open16()] is used, then flags includes at least 1259** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1260** If xOpen() opens a file read-only then it sets *pOutFlags to 1261** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1262** 1263** ^(SQLite will also add one of the following flags to the xOpen() 1264** call, depending on the object being opened: 1265** 1266** <ul> 1267** <li> [SQLITE_OPEN_MAIN_DB] 1268** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1269** <li> [SQLITE_OPEN_TEMP_DB] 1270** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1271** <li> [SQLITE_OPEN_TRANSIENT_DB] 1272** <li> [SQLITE_OPEN_SUBJOURNAL] 1273** <li> [SQLITE_OPEN_SUPER_JOURNAL] 1274** <li> [SQLITE_OPEN_WAL] 1275** </ul>)^ 1276** 1277** The file I/O implementation can use the object type flags to 1278** change the way it deals with files. For example, an application 1279** that does not care about crash recovery or rollback might make 1280** the open of a journal file a no-op. Writes to this journal would 1281** also be no-ops, and any attempt to read the journal would return 1282** SQLITE_IOERR. Or the implementation might recognize that a database 1283** file will be doing page-aligned sector reads and writes in a random 1284** order and set up its I/O subsystem accordingly. 1285** 1286** SQLite might also add one of the following flags to the xOpen method: 1287** 1288** <ul> 1289** <li> [SQLITE_OPEN_DELETEONCLOSE] 1290** <li> [SQLITE_OPEN_EXCLUSIVE] 1291** </ul> 1292** 1293** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1294** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1295** will be set for TEMP databases and their journals, transient 1296** databases, and subjournals. 1297** 1298** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1299** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1300** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1301** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1302** SQLITE_OPEN_CREATE, is used to indicate that file should always 1303** be created, and that it is an error if it already exists. 1304** It is <i>not</i> used to indicate the file should be opened 1305** for exclusive access. 1306** 1307** ^At least szOsFile bytes of memory are allocated by SQLite 1308** to hold the [sqlite3_file] structure passed as the third 1309** argument to xOpen. The xOpen method does not have to 1310** allocate the structure; it should just fill it in. Note that 1311** the xOpen method must set the sqlite3_file.pMethods to either 1312** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1313** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1314** element will be valid after xOpen returns regardless of the success 1315** or failure of the xOpen call. 1316** 1317** [[sqlite3_vfs.xAccess]] 1318** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1319** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1320** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1321** to test whether a file is at least readable. The SQLITE_ACCESS_READ 1322** flag is never actually used and is not implemented in the built-in 1323** VFSes of SQLite. The file is named by the second argument and can be a 1324** directory. The xAccess method returns [SQLITE_OK] on success or some 1325** non-zero error code if there is an I/O error or if the name of 1326** the file given in the second argument is illegal. If SQLITE_OK 1327** is returned, then non-zero or zero is written into *pResOut to indicate 1328** whether or not the file is accessible. 1329** 1330** ^SQLite will always allocate at least mxPathname+1 bytes for the 1331** output buffer xFullPathname. The exact size of the output buffer 1332** is also passed as a parameter to both methods. If the output buffer 1333** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1334** handled as a fatal error by SQLite, vfs implementations should endeavor 1335** to prevent this by setting mxPathname to a sufficiently large value. 1336** 1337** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1338** interfaces are not strictly a part of the filesystem, but they are 1339** included in the VFS structure for completeness. 1340** The xRandomness() function attempts to return nBytes bytes 1341** of good-quality randomness into zOut. The return value is 1342** the actual number of bytes of randomness obtained. 1343** The xSleep() method causes the calling thread to sleep for at 1344** least the number of microseconds given. ^The xCurrentTime() 1345** method returns a Julian Day Number for the current date and time as 1346** a floating point value. 1347** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1348** Day Number multiplied by 86400000 (the number of milliseconds in 1349** a 24-hour day). 1350** ^SQLite will use the xCurrentTimeInt64() method to get the current 1351** date and time if that method is available (if iVersion is 2 or 1352** greater and the function pointer is not NULL) and will fall back 1353** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1354** 1355** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1356** are not used by the SQLite core. These optional interfaces are provided 1357** by some VFSes to facilitate testing of the VFS code. By overriding 1358** system calls with functions under its control, a test program can 1359** simulate faults and error conditions that would otherwise be difficult 1360** or impossible to induce. The set of system calls that can be overridden 1361** varies from one VFS to another, and from one version of the same VFS to the 1362** next. Applications that use these interfaces must be prepared for any 1363** or all of these interfaces to be NULL or for their behavior to change 1364** from one release to the next. Applications must not attempt to access 1365** any of these methods if the iVersion of the VFS is less than 3. 1366*/ 1367typedef struct sqlite3_vfs sqlite3_vfs; 1368typedef void (*sqlite3_syscall_ptr)(void); 1369struct sqlite3_vfs { 1370 int iVersion; /* Structure version number (currently 3) */ 1371 int szOsFile; /* Size of subclassed sqlite3_file */ 1372 int mxPathname; /* Maximum file pathname length */ 1373 sqlite3_vfs *pNext; /* Next registered VFS */ 1374 const char *zName; /* Name of this virtual file system */ 1375 void *pAppData; /* Pointer to application-specific data */ 1376 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1377 int flags, int *pOutFlags); 1378 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1379 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1380 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1381 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1382 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1383 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1384 void (*xDlClose)(sqlite3_vfs*, void*); 1385 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1386 int (*xSleep)(sqlite3_vfs*, int microseconds); 1387 int (*xCurrentTime)(sqlite3_vfs*, double*); 1388 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1389 /* 1390 ** The methods above are in version 1 of the sqlite_vfs object 1391 ** definition. Those that follow are added in version 2 or later 1392 */ 1393 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1394 /* 1395 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1396 ** Those below are for version 3 and greater. 1397 */ 1398 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1399 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1400 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1401 /* 1402 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1403 ** New fields may be appended in future versions. The iVersion 1404 ** value will increment whenever this happens. 1405 */ 1406}; 1407 1408/* 1409** CAPI3REF: Flags for the xAccess VFS method 1410** 1411** These integer constants can be used as the third parameter to 1412** the xAccess method of an [sqlite3_vfs] object. They determine 1413** what kind of permissions the xAccess method is looking for. 1414** With SQLITE_ACCESS_EXISTS, the xAccess method 1415** simply checks whether the file exists. 1416** With SQLITE_ACCESS_READWRITE, the xAccess method 1417** checks whether the named directory is both readable and writable 1418** (in other words, if files can be added, removed, and renamed within 1419** the directory). 1420** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1421** [temp_store_directory pragma], though this could change in a future 1422** release of SQLite. 1423** With SQLITE_ACCESS_READ, the xAccess method 1424** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1425** currently unused, though it might be used in a future release of 1426** SQLite. 1427*/ 1428#define SQLITE_ACCESS_EXISTS 0 1429#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1430#define SQLITE_ACCESS_READ 2 /* Unused */ 1431 1432/* 1433** CAPI3REF: Flags for the xShmLock VFS method 1434** 1435** These integer constants define the various locking operations 1436** allowed by the xShmLock method of [sqlite3_io_methods]. The 1437** following are the only legal combinations of flags to the 1438** xShmLock method: 1439** 1440** <ul> 1441** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1442** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1443** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1444** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1445** </ul> 1446** 1447** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1448** was given on the corresponding lock. 1449** 1450** The xShmLock method can transition between unlocked and SHARED or 1451** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1452** and EXCLUSIVE. 1453*/ 1454#define SQLITE_SHM_UNLOCK 1 1455#define SQLITE_SHM_LOCK 2 1456#define SQLITE_SHM_SHARED 4 1457#define SQLITE_SHM_EXCLUSIVE 8 1458 1459/* 1460** CAPI3REF: Maximum xShmLock index 1461** 1462** The xShmLock method on [sqlite3_io_methods] may use values 1463** between 0 and this upper bound as its "offset" argument. 1464** The SQLite core will never attempt to acquire or release a 1465** lock outside of this range 1466*/ 1467#define SQLITE_SHM_NLOCK 8 1468 1469 1470/* 1471** CAPI3REF: Initialize The SQLite Library 1472** 1473** ^The sqlite3_initialize() routine initializes the 1474** SQLite library. ^The sqlite3_shutdown() routine 1475** deallocates any resources that were allocated by sqlite3_initialize(). 1476** These routines are designed to aid in process initialization and 1477** shutdown on embedded systems. Workstation applications using 1478** SQLite normally do not need to invoke either of these routines. 1479** 1480** A call to sqlite3_initialize() is an "effective" call if it is 1481** the first time sqlite3_initialize() is invoked during the lifetime of 1482** the process, or if it is the first time sqlite3_initialize() is invoked 1483** following a call to sqlite3_shutdown(). ^(Only an effective call 1484** of sqlite3_initialize() does any initialization. All other calls 1485** are harmless no-ops.)^ 1486** 1487** A call to sqlite3_shutdown() is an "effective" call if it is the first 1488** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1489** an effective call to sqlite3_shutdown() does any deinitialization. 1490** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1491** 1492** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1493** is not. The sqlite3_shutdown() interface must only be called from a 1494** single thread. All open [database connections] must be closed and all 1495** other SQLite resources must be deallocated prior to invoking 1496** sqlite3_shutdown(). 1497** 1498** Among other things, ^sqlite3_initialize() will invoke 1499** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1500** will invoke sqlite3_os_end(). 1501** 1502** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1503** ^If for some reason, sqlite3_initialize() is unable to initialize 1504** the library (perhaps it is unable to allocate a needed resource such 1505** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1506** 1507** ^The sqlite3_initialize() routine is called internally by many other 1508** SQLite interfaces so that an application usually does not need to 1509** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1510** calls sqlite3_initialize() so the SQLite library will be automatically 1511** initialized when [sqlite3_open()] is called if it has not be initialized 1512** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1513** compile-time option, then the automatic calls to sqlite3_initialize() 1514** are omitted and the application must call sqlite3_initialize() directly 1515** prior to using any other SQLite interface. For maximum portability, 1516** it is recommended that applications always invoke sqlite3_initialize() 1517** directly prior to using any other SQLite interface. Future releases 1518** of SQLite may require this. In other words, the behavior exhibited 1519** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1520** default behavior in some future release of SQLite. 1521** 1522** The sqlite3_os_init() routine does operating-system specific 1523** initialization of the SQLite library. The sqlite3_os_end() 1524** routine undoes the effect of sqlite3_os_init(). Typical tasks 1525** performed by these routines include allocation or deallocation 1526** of static resources, initialization of global variables, 1527** setting up a default [sqlite3_vfs] module, or setting up 1528** a default configuration using [sqlite3_config()]. 1529** 1530** The application should never invoke either sqlite3_os_init() 1531** or sqlite3_os_end() directly. The application should only invoke 1532** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1533** interface is called automatically by sqlite3_initialize() and 1534** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1535** implementations for sqlite3_os_init() and sqlite3_os_end() 1536** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1537** When [custom builds | built for other platforms] 1538** (using the [SQLITE_OS_OTHER=1] compile-time 1539** option) the application must supply a suitable implementation for 1540** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1541** implementation of sqlite3_os_init() or sqlite3_os_end() 1542** must return [SQLITE_OK] on success and some other [error code] upon 1543** failure. 1544*/ 1545int sqlite3_initialize(void); 1546int sqlite3_shutdown(void); 1547int sqlite3_os_init(void); 1548int sqlite3_os_end(void); 1549 1550/* 1551** CAPI3REF: Configuring The SQLite Library 1552** 1553** The sqlite3_config() interface is used to make global configuration 1554** changes to SQLite in order to tune SQLite to the specific needs of 1555** the application. The default configuration is recommended for most 1556** applications and so this routine is usually not necessary. It is 1557** provided to support rare applications with unusual needs. 1558** 1559** <b>The sqlite3_config() interface is not threadsafe. The application 1560** must ensure that no other SQLite interfaces are invoked by other 1561** threads while sqlite3_config() is running.</b> 1562** 1563** The sqlite3_config() interface 1564** may only be invoked prior to library initialization using 1565** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1566** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1567** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1568** Note, however, that ^sqlite3_config() can be called as part of the 1569** implementation of an application-defined [sqlite3_os_init()]. 1570** 1571** The first argument to sqlite3_config() is an integer 1572** [configuration option] that determines 1573** what property of SQLite is to be configured. Subsequent arguments 1574** vary depending on the [configuration option] 1575** in the first argument. 1576** 1577** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1578** ^If the option is unknown or SQLite is unable to set the option 1579** then this routine returns a non-zero [error code]. 1580*/ 1581int sqlite3_config(int, ...); 1582 1583/* 1584** CAPI3REF: Configure database connections 1585** METHOD: sqlite3 1586** 1587** The sqlite3_db_config() interface is used to make configuration 1588** changes to a [database connection]. The interface is similar to 1589** [sqlite3_config()] except that the changes apply to a single 1590** [database connection] (specified in the first argument). 1591** 1592** The second argument to sqlite3_db_config(D,V,...) is the 1593** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1594** that indicates what aspect of the [database connection] is being configured. 1595** Subsequent arguments vary depending on the configuration verb. 1596** 1597** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1598** the call is considered successful. 1599*/ 1600int sqlite3_db_config(sqlite3*, int op, ...); 1601 1602/* 1603** CAPI3REF: Memory Allocation Routines 1604** 1605** An instance of this object defines the interface between SQLite 1606** and low-level memory allocation routines. 1607** 1608** This object is used in only one place in the SQLite interface. 1609** A pointer to an instance of this object is the argument to 1610** [sqlite3_config()] when the configuration option is 1611** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1612** By creating an instance of this object 1613** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1614** during configuration, an application can specify an alternative 1615** memory allocation subsystem for SQLite to use for all of its 1616** dynamic memory needs. 1617** 1618** Note that SQLite comes with several [built-in memory allocators] 1619** that are perfectly adequate for the overwhelming majority of applications 1620** and that this object is only useful to a tiny minority of applications 1621** with specialized memory allocation requirements. This object is 1622** also used during testing of SQLite in order to specify an alternative 1623** memory allocator that simulates memory out-of-memory conditions in 1624** order to verify that SQLite recovers gracefully from such 1625** conditions. 1626** 1627** The xMalloc, xRealloc, and xFree methods must work like the 1628** malloc(), realloc() and free() functions from the standard C library. 1629** ^SQLite guarantees that the second argument to 1630** xRealloc is always a value returned by a prior call to xRoundup. 1631** 1632** xSize should return the allocated size of a memory allocation 1633** previously obtained from xMalloc or xRealloc. The allocated size 1634** is always at least as big as the requested size but may be larger. 1635** 1636** The xRoundup method returns what would be the allocated size of 1637** a memory allocation given a particular requested size. Most memory 1638** allocators round up memory allocations at least to the next multiple 1639** of 8. Some allocators round up to a larger multiple or to a power of 2. 1640** Every memory allocation request coming in through [sqlite3_malloc()] 1641** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1642** that causes the corresponding memory allocation to fail. 1643** 1644** The xInit method initializes the memory allocator. For example, 1645** it might allocate any required mutexes or initialize internal data 1646** structures. The xShutdown method is invoked (indirectly) by 1647** [sqlite3_shutdown()] and should deallocate any resources acquired 1648** by xInit. The pAppData pointer is used as the only parameter to 1649** xInit and xShutdown. 1650** 1651** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes 1652** the xInit method, so the xInit method need not be threadsafe. The 1653** xShutdown method is only called from [sqlite3_shutdown()] so it does 1654** not need to be threadsafe either. For all other methods, SQLite 1655** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1656** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1657** it is by default) and so the methods are automatically serialized. 1658** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1659** methods must be threadsafe or else make their own arrangements for 1660** serialization. 1661** 1662** SQLite will never invoke xInit() more than once without an intervening 1663** call to xShutdown(). 1664*/ 1665typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1666struct sqlite3_mem_methods { 1667 void *(*xMalloc)(int); /* Memory allocation function */ 1668 void (*xFree)(void*); /* Free a prior allocation */ 1669 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1670 int (*xSize)(void*); /* Return the size of an allocation */ 1671 int (*xRoundup)(int); /* Round up request size to allocation size */ 1672 int (*xInit)(void*); /* Initialize the memory allocator */ 1673 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1674 void *pAppData; /* Argument to xInit() and xShutdown() */ 1675}; 1676 1677/* 1678** CAPI3REF: Configuration Options 1679** KEYWORDS: {configuration option} 1680** 1681** These constants are the available integer configuration options that 1682** can be passed as the first argument to the [sqlite3_config()] interface. 1683** 1684** New configuration options may be added in future releases of SQLite. 1685** Existing configuration options might be discontinued. Applications 1686** should check the return code from [sqlite3_config()] to make sure that 1687** the call worked. The [sqlite3_config()] interface will return a 1688** non-zero [error code] if a discontinued or unsupported configuration option 1689** is invoked. 1690** 1691** <dl> 1692** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1693** <dd>There are no arguments to this option. ^This option sets the 1694** [threading mode] to Single-thread. In other words, it disables 1695** all mutexing and puts SQLite into a mode where it can only be used 1696** by a single thread. ^If SQLite is compiled with 1697** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1698** it is not possible to change the [threading mode] from its default 1699** value of Single-thread and so [sqlite3_config()] will return 1700** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1701** configuration option.</dd> 1702** 1703** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1704** <dd>There are no arguments to this option. ^This option sets the 1705** [threading mode] to Multi-thread. In other words, it disables 1706** mutexing on [database connection] and [prepared statement] objects. 1707** The application is responsible for serializing access to 1708** [database connections] and [prepared statements]. But other mutexes 1709** are enabled so that SQLite will be safe to use in a multi-threaded 1710** environment as long as no two threads attempt to use the same 1711** [database connection] at the same time. ^If SQLite is compiled with 1712** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1713** it is not possible to set the Multi-thread [threading mode] and 1714** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1715** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1716** 1717** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1718** <dd>There are no arguments to this option. ^This option sets the 1719** [threading mode] to Serialized. In other words, this option enables 1720** all mutexes including the recursive 1721** mutexes on [database connection] and [prepared statement] objects. 1722** In this mode (which is the default when SQLite is compiled with 1723** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1724** to [database connections] and [prepared statements] so that the 1725** application is free to use the same [database connection] or the 1726** same [prepared statement] in different threads at the same time. 1727** ^If SQLite is compiled with 1728** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1729** it is not possible to set the Serialized [threading mode] and 1730** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1731** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1732** 1733** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1734** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1735** a pointer to an instance of the [sqlite3_mem_methods] structure. 1736** The argument specifies 1737** alternative low-level memory allocation routines to be used in place of 1738** the memory allocation routines built into SQLite.)^ ^SQLite makes 1739** its own private copy of the content of the [sqlite3_mem_methods] structure 1740** before the [sqlite3_config()] call returns.</dd> 1741** 1742** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1743** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1744** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1745** The [sqlite3_mem_methods] 1746** structure is filled with the currently defined memory allocation routines.)^ 1747** This option can be used to overload the default memory allocation 1748** routines with a wrapper that simulations memory allocation failure or 1749** tracks memory usage, for example. </dd> 1750** 1751** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1752** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1753** type int, interpreted as a boolean, which if true provides a hint to 1754** SQLite that it should avoid large memory allocations if possible. 1755** SQLite will run faster if it is free to make large memory allocations, 1756** but some application might prefer to run slower in exchange for 1757** guarantees about memory fragmentation that are possible if large 1758** allocations are avoided. This hint is normally off. 1759** </dd> 1760** 1761** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1762** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1763** interpreted as a boolean, which enables or disables the collection of 1764** memory allocation statistics. ^(When memory allocation statistics are 1765** disabled, the following SQLite interfaces become non-operational: 1766** <ul> 1767** <li> [sqlite3_hard_heap_limit64()] 1768** <li> [sqlite3_memory_used()] 1769** <li> [sqlite3_memory_highwater()] 1770** <li> [sqlite3_soft_heap_limit64()] 1771** <li> [sqlite3_status64()] 1772** </ul>)^ 1773** ^Memory allocation statistics are enabled by default unless SQLite is 1774** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1775** allocation statistics are disabled by default. 1776** </dd> 1777** 1778** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1779** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1780** </dd> 1781** 1782** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1783** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1784** that SQLite can use for the database page cache with the default page 1785** cache implementation. 1786** This configuration option is a no-op if an application-defined page 1787** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1788** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1789** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1790** and the number of cache lines (N). 1791** The sz argument should be the size of the largest database page 1792** (a power of two between 512 and 65536) plus some extra bytes for each 1793** page header. ^The number of extra bytes needed by the page header 1794** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1795** ^It is harmless, apart from the wasted memory, 1796** for the sz parameter to be larger than necessary. The pMem 1797** argument must be either a NULL pointer or a pointer to an 8-byte 1798** aligned block of memory of at least sz*N bytes, otherwise 1799** subsequent behavior is undefined. 1800** ^When pMem is not NULL, SQLite will strive to use the memory provided 1801** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1802** a page cache line is larger than sz bytes or if all of the pMem buffer 1803** is exhausted. 1804** ^If pMem is NULL and N is non-zero, then each database connection 1805** does an initial bulk allocation for page cache memory 1806** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1807** of -1024*N bytes if N is negative, . ^If additional 1808** page cache memory is needed beyond what is provided by the initial 1809** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1810** additional cache line. </dd> 1811** 1812** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1813** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1814** that SQLite will use for all of its dynamic memory allocation needs 1815** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1816** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1817** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1818** [SQLITE_ERROR] if invoked otherwise. 1819** ^There are three arguments to SQLITE_CONFIG_HEAP: 1820** An 8-byte aligned pointer to the memory, 1821** the number of bytes in the memory buffer, and the minimum allocation size. 1822** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1823** to using its default memory allocator (the system malloc() implementation), 1824** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1825** memory pointer is not NULL then the alternative memory 1826** allocator is engaged to handle all of SQLites memory allocation needs. 1827** The first pointer (the memory pointer) must be aligned to an 8-byte 1828** boundary or subsequent behavior of SQLite will be undefined. 1829** The minimum allocation size is capped at 2**12. Reasonable values 1830** for the minimum allocation size are 2**5 through 2**8.</dd> 1831** 1832** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1833** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1834** pointer to an instance of the [sqlite3_mutex_methods] structure. 1835** The argument specifies alternative low-level mutex routines to be used 1836** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1837** the content of the [sqlite3_mutex_methods] structure before the call to 1838** [sqlite3_config()] returns. ^If SQLite is compiled with 1839** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1840** the entire mutexing subsystem is omitted from the build and hence calls to 1841** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1842** return [SQLITE_ERROR].</dd> 1843** 1844** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1845** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1846** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1847** [sqlite3_mutex_methods] 1848** structure is filled with the currently defined mutex routines.)^ 1849** This option can be used to overload the default mutex allocation 1850** routines with a wrapper used to track mutex usage for performance 1851** profiling or testing, for example. ^If SQLite is compiled with 1852** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1853** the entire mutexing subsystem is omitted from the build and hence calls to 1854** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1855** return [SQLITE_ERROR].</dd> 1856** 1857** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1858** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1859** the default size of lookaside memory on each [database connection]. 1860** The first argument is the 1861** size of each lookaside buffer slot and the second is the number of 1862** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1863** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1864** option to [sqlite3_db_config()] can be used to change the lookaside 1865** configuration on individual connections.)^ </dd> 1866** 1867** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1868** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1869** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1870** the interface to a custom page cache implementation.)^ 1871** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1872** 1873** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1874** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1875** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1876** the current page cache implementation into that object.)^ </dd> 1877** 1878** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1879** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1880** global [error log]. 1881** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1882** function with a call signature of void(*)(void*,int,const char*), 1883** and a pointer to void. ^If the function pointer is not NULL, it is 1884** invoked by [sqlite3_log()] to process each logging event. ^If the 1885** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1886** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1887** passed through as the first parameter to the application-defined logger 1888** function whenever that function is invoked. ^The second parameter to 1889** the logger function is a copy of the first parameter to the corresponding 1890** [sqlite3_log()] call and is intended to be a [result code] or an 1891** [extended result code]. ^The third parameter passed to the logger is 1892** log message after formatting via [sqlite3_snprintf()]. 1893** The SQLite logging interface is not reentrant; the logger function 1894** supplied by the application must not invoke any SQLite interface. 1895** In a multi-threaded application, the application-defined logger 1896** function must be threadsafe. </dd> 1897** 1898** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1899** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1900** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1901** then URI handling is globally disabled.)^ ^If URI handling is globally 1902** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1903** [sqlite3_open16()] or 1904** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1905** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1906** connection is opened. ^If it is globally disabled, filenames are 1907** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1908** database connection is opened. ^(By default, URI handling is globally 1909** disabled. The default value may be changed by compiling with the 1910** [SQLITE_USE_URI] symbol defined.)^ 1911** 1912** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1913** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1914** argument which is interpreted as a boolean in order to enable or disable 1915** the use of covering indices for full table scans in the query optimizer. 1916** ^The default setting is determined 1917** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1918** if that compile-time option is omitted. 1919** The ability to disable the use of covering indices for full table scans 1920** is because some incorrectly coded legacy applications might malfunction 1921** when the optimization is enabled. Providing the ability to 1922** disable the optimization allows the older, buggy application code to work 1923** without change even with newer versions of SQLite. 1924** 1925** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1926** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1927** <dd> These options are obsolete and should not be used by new code. 1928** They are retained for backwards compatibility but are now no-ops. 1929** </dd> 1930** 1931** [[SQLITE_CONFIG_SQLLOG]] 1932** <dt>SQLITE_CONFIG_SQLLOG 1933** <dd>This option is only available if sqlite is compiled with the 1934** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1935** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1936** The second should be of type (void*). The callback is invoked by the library 1937** in three separate circumstances, identified by the value passed as the 1938** fourth parameter. If the fourth parameter is 0, then the database connection 1939** passed as the second argument has just been opened. The third argument 1940** points to a buffer containing the name of the main database file. If the 1941** fourth parameter is 1, then the SQL statement that the third parameter 1942** points to has just been executed. Or, if the fourth parameter is 2, then 1943** the connection being passed as the second parameter is being closed. The 1944** third parameter is passed NULL In this case. An example of using this 1945** configuration option can be seen in the "test_sqllog.c" source file in 1946** the canonical SQLite source tree.</dd> 1947** 1948** [[SQLITE_CONFIG_MMAP_SIZE]] 1949** <dt>SQLITE_CONFIG_MMAP_SIZE 1950** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1951** that are the default mmap size limit (the default setting for 1952** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1953** ^The default setting can be overridden by each database connection using 1954** either the [PRAGMA mmap_size] command, or by using the 1955** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1956** will be silently truncated if necessary so that it does not exceed the 1957** compile-time maximum mmap size set by the 1958** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1959** ^If either argument to this option is negative, then that argument is 1960** changed to its compile-time default. 1961** 1962** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1963** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1964** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1965** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1966** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1967** that specifies the maximum size of the created heap. 1968** 1969** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1970** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1971** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1972** is a pointer to an integer and writes into that integer the number of extra 1973** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1974** The amount of extra space required can change depending on the compiler, 1975** target platform, and SQLite version. 1976** 1977** [[SQLITE_CONFIG_PMASZ]] 1978** <dt>SQLITE_CONFIG_PMASZ 1979** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1980** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1981** sorter to that integer. The default minimum PMA Size is set by the 1982** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1983** to help with sort operations when multithreaded sorting 1984** is enabled (using the [PRAGMA threads] command) and the amount of content 1985** to be sorted exceeds the page size times the minimum of the 1986** [PRAGMA cache_size] setting and this value. 1987** 1988** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1989** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1990** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1991** becomes the [statement journal] spill-to-disk threshold. 1992** [Statement journals] are held in memory until their size (in bytes) 1993** exceeds this threshold, at which point they are written to disk. 1994** Or if the threshold is -1, statement journals are always held 1995** exclusively in memory. 1996** Since many statement journals never become large, setting the spill 1997** threshold to a value such as 64KiB can greatly reduce the amount of 1998** I/O required to support statement rollback. 1999** The default value for this setting is controlled by the 2000** [SQLITE_STMTJRNL_SPILL] compile-time option. 2001** 2002** [[SQLITE_CONFIG_SORTERREF_SIZE]] 2003** <dt>SQLITE_CONFIG_SORTERREF_SIZE 2004** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter 2005** of type (int) - the new value of the sorter-reference size threshold. 2006** Usually, when SQLite uses an external sort to order records according 2007** to an ORDER BY clause, all fields required by the caller are present in the 2008** sorted records. However, if SQLite determines based on the declared type 2009** of a table column that its values are likely to be very large - larger 2010** than the configured sorter-reference size threshold - then a reference 2011** is stored in each sorted record and the required column values loaded 2012** from the database as records are returned in sorted order. The default 2013** value for this option is to never use this optimization. Specifying a 2014** negative value for this option restores the default behaviour. 2015** This option is only available if SQLite is compiled with the 2016** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option. 2017** 2018** [[SQLITE_CONFIG_MEMDB_MAXSIZE]] 2019** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE 2020** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter 2021** [sqlite3_int64] parameter which is the default maximum size for an in-memory 2022** database created using [sqlite3_deserialize()]. This default maximum 2023** size can be adjusted up or down for individual databases using the 2024** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control]. If this 2025** configuration setting is never used, then the default maximum is determined 2026** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option. If that 2027** compile-time option is not set, then the default maximum is 1073741824. 2028** </dl> 2029*/ 2030#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 2031#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 2032#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 2033#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 2034#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 2035#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 2036#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 2037#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 2038#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 2039#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 2040#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 2041/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 2042#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 2043#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 2044#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 2045#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 2046#define SQLITE_CONFIG_URI 17 /* int */ 2047#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 2048#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 2049#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 2050#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 2051#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 2052#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 2053#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 2054#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 2055#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 2056#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 2057#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */ 2058#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */ 2059 2060/* 2061** CAPI3REF: Database Connection Configuration Options 2062** 2063** These constants are the available integer configuration options that 2064** can be passed as the second argument to the [sqlite3_db_config()] interface. 2065** 2066** New configuration options may be added in future releases of SQLite. 2067** Existing configuration options might be discontinued. Applications 2068** should check the return code from [sqlite3_db_config()] to make sure that 2069** the call worked. ^The [sqlite3_db_config()] interface will return a 2070** non-zero [error code] if a discontinued or unsupported configuration option 2071** is invoked. 2072** 2073** <dl> 2074** [[SQLITE_DBCONFIG_LOOKASIDE]] 2075** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 2076** <dd> ^This option takes three additional arguments that determine the 2077** [lookaside memory allocator] configuration for the [database connection]. 2078** ^The first argument (the third parameter to [sqlite3_db_config()] is a 2079** pointer to a memory buffer to use for lookaside memory. 2080** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 2081** may be NULL in which case SQLite will allocate the 2082** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 2083** size of each lookaside buffer slot. ^The third argument is the number of 2084** slots. The size of the buffer in the first argument must be greater than 2085** or equal to the product of the second and third arguments. The buffer 2086** must be aligned to an 8-byte boundary. ^If the second argument to 2087** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 2088** rounded down to the next smaller multiple of 8. ^(The lookaside memory 2089** configuration for a database connection can only be changed when that 2090** connection is not currently using lookaside memory, or in other words 2091** when the "current value" returned by 2092** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 2093** Any attempt to change the lookaside memory configuration when lookaside 2094** memory is in use leaves the configuration unchanged and returns 2095** [SQLITE_BUSY].)^</dd> 2096** 2097** [[SQLITE_DBCONFIG_ENABLE_FKEY]] 2098** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 2099** <dd> ^This option is used to enable or disable the enforcement of 2100** [foreign key constraints]. There should be two additional arguments. 2101** The first argument is an integer which is 0 to disable FK enforcement, 2102** positive to enable FK enforcement or negative to leave FK enforcement 2103** unchanged. The second parameter is a pointer to an integer into which 2104** is written 0 or 1 to indicate whether FK enforcement is off or on 2105** following this call. The second parameter may be a NULL pointer, in 2106** which case the FK enforcement setting is not reported back. </dd> 2107** 2108** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]] 2109** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2110** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2111** There should be two additional arguments. 2112** The first argument is an integer which is 0 to disable triggers, 2113** positive to enable triggers or negative to leave the setting unchanged. 2114** The second parameter is a pointer to an integer into which 2115** is written 0 or 1 to indicate whether triggers are disabled or enabled 2116** following this call. The second parameter may be a NULL pointer, in 2117** which case the trigger setting is not reported back. </dd> 2118** 2119** [[SQLITE_DBCONFIG_ENABLE_VIEW]] 2120** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt> 2121** <dd> ^This option is used to enable or disable [CREATE VIEW | views]. 2122** There should be two additional arguments. 2123** The first argument is an integer which is 0 to disable views, 2124** positive to enable views or negative to leave the setting unchanged. 2125** The second parameter is a pointer to an integer into which 2126** is written 0 or 1 to indicate whether views are disabled or enabled 2127** following this call. The second parameter may be a NULL pointer, in 2128** which case the view setting is not reported back. </dd> 2129** 2130** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]] 2131** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2132** <dd> ^This option is used to enable or disable the 2133** [fts3_tokenizer()] function which is part of the 2134** [FTS3] full-text search engine extension. 2135** There should be two additional arguments. 2136** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2137** positive to enable fts3_tokenizer() or negative to leave the setting 2138** unchanged. 2139** The second parameter is a pointer to an integer into which 2140** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2141** following this call. The second parameter may be a NULL pointer, in 2142** which case the new setting is not reported back. </dd> 2143** 2144** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]] 2145** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2146** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2147** interface independently of the [load_extension()] SQL function. 2148** The [sqlite3_enable_load_extension()] API enables or disables both the 2149** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2150** There should be two additional arguments. 2151** When the first argument to this interface is 1, then only the C-API is 2152** enabled and the SQL function remains disabled. If the first argument to 2153** this interface is 0, then both the C-API and the SQL function are disabled. 2154** If the first argument is -1, then no changes are made to state of either the 2155** C-API or the SQL function. 2156** The second parameter is a pointer to an integer into which 2157** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2158** is disabled or enabled following this call. The second parameter may 2159** be a NULL pointer, in which case the new setting is not reported back. 2160** </dd> 2161** 2162** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2163** <dd> ^This option is used to change the name of the "main" database 2164** schema. ^The sole argument is a pointer to a constant UTF8 string 2165** which will become the new schema name in place of "main". ^SQLite 2166** does not make a copy of the new main schema name string, so the application 2167** must ensure that the argument passed into this DBCONFIG option is unchanged 2168** until after the database connection closes. 2169** </dd> 2170** 2171** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]] 2172** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2173** <dd> Usually, when a database in wal mode is closed or detached from a 2174** database handle, SQLite checks if this will mean that there are now no 2175** connections at all to the database. If so, it performs a checkpoint 2176** operation before closing the connection. This option may be used to 2177** override this behaviour. The first parameter passed to this operation 2178** is an integer - positive to disable checkpoints-on-close, or zero (the 2179** default) to enable them, and negative to leave the setting unchanged. 2180** The second parameter is a pointer to an integer 2181** into which is written 0 or 1 to indicate whether checkpoints-on-close 2182** have been disabled - 0 if they are not disabled, 1 if they are. 2183** </dd> 2184** 2185** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2186** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2187** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2188** a single SQL query statement will always use the same algorithm regardless 2189** of values of [bound parameters].)^ The QPSG disables some query optimizations 2190** that look at the values of bound parameters, which can make some queries 2191** slower. But the QPSG has the advantage of more predictable behavior. With 2192** the QPSG active, SQLite will always use the same query plan in the field as 2193** was used during testing in the lab. 2194** The first argument to this setting is an integer which is 0 to disable 2195** the QPSG, positive to enable QPSG, or negative to leave the setting 2196** unchanged. The second parameter is a pointer to an integer into which 2197** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2198** following this call. 2199** </dd> 2200** 2201** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2202** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2203** include output for any operations performed by trigger programs. This 2204** option is used to set or clear (the default) a flag that governs this 2205** behavior. The first parameter passed to this operation is an integer - 2206** positive to enable output for trigger programs, or zero to disable it, 2207** or negative to leave the setting unchanged. 2208** The second parameter is a pointer to an integer into which is written 2209** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2210** it is not disabled, 1 if it is. 2211** </dd> 2212** 2213** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt> 2214** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run 2215** [VACUUM] in order to reset a database back to an empty database 2216** with no schema and no content. The following process works even for 2217** a badly corrupted database file: 2218** <ol> 2219** <li> If the database connection is newly opened, make sure it has read the 2220** database schema by preparing then discarding some query against the 2221** database, or calling sqlite3_table_column_metadata(), ignoring any 2222** errors. This step is only necessary if the application desires to keep 2223** the database in WAL mode after the reset if it was in WAL mode before 2224** the reset. 2225** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0); 2226** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0); 2227** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0); 2228** </ol> 2229** Because resetting a database is destructive and irreversible, the 2230** process requires the use of this obscure API and multiple steps to help 2231** ensure that it does not happen by accident. 2232** 2233** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt> 2234** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the 2235** "defensive" flag for a database connection. When the defensive 2236** flag is enabled, language features that allow ordinary SQL to 2237** deliberately corrupt the database file are disabled. The disabled 2238** features include but are not limited to the following: 2239** <ul> 2240** <li> The [PRAGMA writable_schema=ON] statement. 2241** <li> The [PRAGMA journal_mode=OFF] statement. 2242** <li> Writes to the [sqlite_dbpage] virtual table. 2243** <li> Direct writes to [shadow tables]. 2244** </ul> 2245** </dd> 2246** 2247** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt> 2248** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the 2249** "writable_schema" flag. This has the same effect and is logically equivalent 2250** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF]. 2251** The first argument to this setting is an integer which is 0 to disable 2252** the writable_schema, positive to enable writable_schema, or negative to 2253** leave the setting unchanged. The second parameter is a pointer to an 2254** integer into which is written 0 or 1 to indicate whether the writable_schema 2255** is enabled or disabled following this call. 2256** </dd> 2257** 2258** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]] 2259** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt> 2260** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates 2261** the legacy behavior of the [ALTER TABLE RENAME] command such it 2262** behaves as it did prior to [version 3.24.0] (2018-06-04). See the 2263** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for 2264** additional information. This feature can also be turned on and off 2265** using the [PRAGMA legacy_alter_table] statement. 2266** </dd> 2267** 2268** [[SQLITE_DBCONFIG_DQS_DML]] 2269** <dt>SQLITE_DBCONFIG_DQS_DML</td> 2270** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates 2271** the legacy [double-quoted string literal] misfeature for DML statements 2272** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The 2273** default value of this setting is determined by the [-DSQLITE_DQS] 2274** compile-time option. 2275** </dd> 2276** 2277** [[SQLITE_DBCONFIG_DQS_DDL]] 2278** <dt>SQLITE_DBCONFIG_DQS_DDL</td> 2279** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates 2280** the legacy [double-quoted string literal] misfeature for DDL statements, 2281** such as CREATE TABLE and CREATE INDEX. The 2282** default value of this setting is determined by the [-DSQLITE_DQS] 2283** compile-time option. 2284** </dd> 2285** 2286** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]] 2287** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td> 2288** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to 2289** assume that database schemas are untainted by malicious content. 2290** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite 2291** takes additional defensive steps to protect the application from harm 2292** including: 2293** <ul> 2294** <li> Prohibit the use of SQL functions inside triggers, views, 2295** CHECK constraints, DEFAULT clauses, expression indexes, 2296** partial indexes, or generated columns 2297** unless those functions are tagged with [SQLITE_INNOCUOUS]. 2298** <li> Prohibit the use of virtual tables inside of triggers or views 2299** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS]. 2300** </ul> 2301** This setting defaults to "on" for legacy compatibility, however 2302** all applications are advised to turn it off if possible. This setting 2303** can also be controlled using the [PRAGMA trusted_schema] statement. 2304** </dd> 2305** 2306** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]] 2307** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td> 2308** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates 2309** the legacy file format flag. When activated, this flag causes all newly 2310** created database file to have a schema format version number (the 4-byte 2311** integer found at offset 44 into the database header) of 1. This in turn 2312** means that the resulting database file will be readable and writable by 2313** any SQLite version back to 3.0.0 ([dateof:3.0.0]). Without this setting, 2314** newly created databases are generally not understandable by SQLite versions 2315** prior to 3.3.0 ([dateof:3.3.0]). As these words are written, there 2316** is now scarcely any need to generated database files that are compatible 2317** all the way back to version 3.0.0, and so this setting is of little 2318** practical use, but is provided so that SQLite can continue to claim the 2319** ability to generate new database files that are compatible with version 2320** 3.0.0. 2321** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on, 2322** the [VACUUM] command will fail with an obscure error when attempting to 2323** process a table with generated columns and a descending index. This is 2324** not considered a bug since SQLite versions 3.3.0 and earlier do not support 2325** either generated columns or decending indexes. 2326** </dd> 2327** </dl> 2328*/ 2329#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2330#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2331#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2332#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2333#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2334#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2335#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2336#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2337#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2338#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */ 2339#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */ 2340#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */ 2341#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */ 2342#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */ 2343#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */ 2344#define SQLITE_DBCONFIG_ENABLE_VIEW 1015 /* int int* */ 2345#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT 1016 /* int int* */ 2346#define SQLITE_DBCONFIG_TRUSTED_SCHEMA 1017 /* int int* */ 2347#define SQLITE_DBCONFIG_MAX 1017 /* Largest DBCONFIG */ 2348 2349/* 2350** CAPI3REF: Enable Or Disable Extended Result Codes 2351** METHOD: sqlite3 2352** 2353** ^The sqlite3_extended_result_codes() routine enables or disables the 2354** [extended result codes] feature of SQLite. ^The extended result 2355** codes are disabled by default for historical compatibility. 2356*/ 2357int sqlite3_extended_result_codes(sqlite3*, int onoff); 2358 2359/* 2360** CAPI3REF: Last Insert Rowid 2361** METHOD: sqlite3 2362** 2363** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2364** has a unique 64-bit signed 2365** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2366** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2367** names are not also used by explicitly declared columns. ^If 2368** the table has a column of type [INTEGER PRIMARY KEY] then that column 2369** is another alias for the rowid. 2370** 2371** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2372** the most recent successful [INSERT] into a rowid table or [virtual table] 2373** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2374** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2375** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2376** zero. 2377** 2378** As well as being set automatically as rows are inserted into database 2379** tables, the value returned by this function may be set explicitly by 2380** [sqlite3_set_last_insert_rowid()] 2381** 2382** Some virtual table implementations may INSERT rows into rowid tables as 2383** part of committing a transaction (e.g. to flush data accumulated in memory 2384** to disk). In this case subsequent calls to this function return the rowid 2385** associated with these internal INSERT operations, which leads to 2386** unintuitive results. Virtual table implementations that do write to rowid 2387** tables in this way can avoid this problem by restoring the original 2388** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2389** control to the user. 2390** 2391** ^(If an [INSERT] occurs within a trigger then this routine will 2392** return the [rowid] of the inserted row as long as the trigger is 2393** running. Once the trigger program ends, the value returned 2394** by this routine reverts to what it was before the trigger was fired.)^ 2395** 2396** ^An [INSERT] that fails due to a constraint violation is not a 2397** successful [INSERT] and does not change the value returned by this 2398** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2399** and INSERT OR ABORT make no changes to the return value of this 2400** routine when their insertion fails. ^(When INSERT OR REPLACE 2401** encounters a constraint violation, it does not fail. The 2402** INSERT continues to completion after deleting rows that caused 2403** the constraint problem so INSERT OR REPLACE will always change 2404** the return value of this interface.)^ 2405** 2406** ^For the purposes of this routine, an [INSERT] is considered to 2407** be successful even if it is subsequently rolled back. 2408** 2409** This function is accessible to SQL statements via the 2410** [last_insert_rowid() SQL function]. 2411** 2412** If a separate thread performs a new [INSERT] on the same 2413** database connection while the [sqlite3_last_insert_rowid()] 2414** function is running and thus changes the last insert [rowid], 2415** then the value returned by [sqlite3_last_insert_rowid()] is 2416** unpredictable and might not equal either the old or the new 2417** last insert [rowid]. 2418*/ 2419sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2420 2421/* 2422** CAPI3REF: Set the Last Insert Rowid value. 2423** METHOD: sqlite3 2424** 2425** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2426** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2427** without inserting a row into the database. 2428*/ 2429void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2430 2431/* 2432** CAPI3REF: Count The Number Of Rows Modified 2433** METHOD: sqlite3 2434** 2435** ^This function returns the number of rows modified, inserted or 2436** deleted by the most recently completed INSERT, UPDATE or DELETE 2437** statement on the database connection specified by the only parameter. 2438** ^Executing any other type of SQL statement does not modify the value 2439** returned by this function. 2440** 2441** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2442** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2443** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2444** 2445** Changes to a view that are intercepted by 2446** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2447** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2448** DELETE statement run on a view is always zero. Only changes made to real 2449** tables are counted. 2450** 2451** Things are more complicated if the sqlite3_changes() function is 2452** executed while a trigger program is running. This may happen if the 2453** program uses the [changes() SQL function], or if some other callback 2454** function invokes sqlite3_changes() directly. Essentially: 2455** 2456** <ul> 2457** <li> ^(Before entering a trigger program the value returned by 2458** sqlite3_changes() function is saved. After the trigger program 2459** has finished, the original value is restored.)^ 2460** 2461** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2462** statement sets the value returned by sqlite3_changes() 2463** upon completion as normal. Of course, this value will not include 2464** any changes performed by sub-triggers, as the sqlite3_changes() 2465** value will be saved and restored after each sub-trigger has run.)^ 2466** </ul> 2467** 2468** ^This means that if the changes() SQL function (or similar) is used 2469** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2470** returns the value as set when the calling statement began executing. 2471** ^If it is used by the second or subsequent such statement within a trigger 2472** program, the value returned reflects the number of rows modified by the 2473** previous INSERT, UPDATE or DELETE statement within the same trigger. 2474** 2475** If a separate thread makes changes on the same database connection 2476** while [sqlite3_changes()] is running then the value returned 2477** is unpredictable and not meaningful. 2478** 2479** See also: 2480** <ul> 2481** <li> the [sqlite3_total_changes()] interface 2482** <li> the [count_changes pragma] 2483** <li> the [changes() SQL function] 2484** <li> the [data_version pragma] 2485** </ul> 2486*/ 2487int sqlite3_changes(sqlite3*); 2488 2489/* 2490** CAPI3REF: Total Number Of Rows Modified 2491** METHOD: sqlite3 2492** 2493** ^This function returns the total number of rows inserted, modified or 2494** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2495** since the database connection was opened, including those executed as 2496** part of trigger programs. ^Executing any other type of SQL statement 2497** does not affect the value returned by sqlite3_total_changes(). 2498** 2499** ^Changes made as part of [foreign key actions] are included in the 2500** count, but those made as part of REPLACE constraint resolution are 2501** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2502** are not counted. 2503** 2504** The [sqlite3_total_changes(D)] interface only reports the number 2505** of rows that changed due to SQL statement run against database 2506** connection D. Any changes by other database connections are ignored. 2507** To detect changes against a database file from other database 2508** connections use the [PRAGMA data_version] command or the 2509** [SQLITE_FCNTL_DATA_VERSION] [file control]. 2510** 2511** If a separate thread makes changes on the same database connection 2512** while [sqlite3_total_changes()] is running then the value 2513** returned is unpredictable and not meaningful. 2514** 2515** See also: 2516** <ul> 2517** <li> the [sqlite3_changes()] interface 2518** <li> the [count_changes pragma] 2519** <li> the [changes() SQL function] 2520** <li> the [data_version pragma] 2521** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control] 2522** </ul> 2523*/ 2524int sqlite3_total_changes(sqlite3*); 2525 2526/* 2527** CAPI3REF: Interrupt A Long-Running Query 2528** METHOD: sqlite3 2529** 2530** ^This function causes any pending database operation to abort and 2531** return at its earliest opportunity. This routine is typically 2532** called in response to a user action such as pressing "Cancel" 2533** or Ctrl-C where the user wants a long query operation to halt 2534** immediately. 2535** 2536** ^It is safe to call this routine from a thread different from the 2537** thread that is currently running the database operation. But it 2538** is not safe to call this routine with a [database connection] that 2539** is closed or might close before sqlite3_interrupt() returns. 2540** 2541** ^If an SQL operation is very nearly finished at the time when 2542** sqlite3_interrupt() is called, then it might not have an opportunity 2543** to be interrupted and might continue to completion. 2544** 2545** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2546** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2547** that is inside an explicit transaction, then the entire transaction 2548** will be rolled back automatically. 2549** 2550** ^The sqlite3_interrupt(D) call is in effect until all currently running 2551** SQL statements on [database connection] D complete. ^Any new SQL statements 2552** that are started after the sqlite3_interrupt() call and before the 2553** running statement count reaches zero are interrupted as if they had been 2554** running prior to the sqlite3_interrupt() call. ^New SQL statements 2555** that are started after the running statement count reaches zero are 2556** not effected by the sqlite3_interrupt(). 2557** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2558** SQL statements is a no-op and has no effect on SQL statements 2559** that are started after the sqlite3_interrupt() call returns. 2560*/ 2561void sqlite3_interrupt(sqlite3*); 2562 2563/* 2564** CAPI3REF: Determine If An SQL Statement Is Complete 2565** 2566** These routines are useful during command-line input to determine if the 2567** currently entered text seems to form a complete SQL statement or 2568** if additional input is needed before sending the text into 2569** SQLite for parsing. ^These routines return 1 if the input string 2570** appears to be a complete SQL statement. ^A statement is judged to be 2571** complete if it ends with a semicolon token and is not a prefix of a 2572** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2573** string literals or quoted identifier names or comments are not 2574** independent tokens (they are part of the token in which they are 2575** embedded) and thus do not count as a statement terminator. ^Whitespace 2576** and comments that follow the final semicolon are ignored. 2577** 2578** ^These routines return 0 if the statement is incomplete. ^If a 2579** memory allocation fails, then SQLITE_NOMEM is returned. 2580** 2581** ^These routines do not parse the SQL statements thus 2582** will not detect syntactically incorrect SQL. 2583** 2584** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2585** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2586** automatically by sqlite3_complete16(). If that initialization fails, 2587** then the return value from sqlite3_complete16() will be non-zero 2588** regardless of whether or not the input SQL is complete.)^ 2589** 2590** The input to [sqlite3_complete()] must be a zero-terminated 2591** UTF-8 string. 2592** 2593** The input to [sqlite3_complete16()] must be a zero-terminated 2594** UTF-16 string in native byte order. 2595*/ 2596int sqlite3_complete(const char *sql); 2597int sqlite3_complete16(const void *sql); 2598 2599/* 2600** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2601** KEYWORDS: {busy-handler callback} {busy handler} 2602** METHOD: sqlite3 2603** 2604** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2605** that might be invoked with argument P whenever 2606** an attempt is made to access a database table associated with 2607** [database connection] D when another thread 2608** or process has the table locked. 2609** The sqlite3_busy_handler() interface is used to implement 2610** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2611** 2612** ^If the busy callback is NULL, then [SQLITE_BUSY] 2613** is returned immediately upon encountering the lock. ^If the busy callback 2614** is not NULL, then the callback might be invoked with two arguments. 2615** 2616** ^The first argument to the busy handler is a copy of the void* pointer which 2617** is the third argument to sqlite3_busy_handler(). ^The second argument to 2618** the busy handler callback is the number of times that the busy handler has 2619** been invoked previously for the same locking event. ^If the 2620** busy callback returns 0, then no additional attempts are made to 2621** access the database and [SQLITE_BUSY] is returned 2622** to the application. 2623** ^If the callback returns non-zero, then another attempt 2624** is made to access the database and the cycle repeats. 2625** 2626** The presence of a busy handler does not guarantee that it will be invoked 2627** when there is lock contention. ^If SQLite determines that invoking the busy 2628** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2629** to the application instead of invoking the 2630** busy handler. 2631** Consider a scenario where one process is holding a read lock that 2632** it is trying to promote to a reserved lock and 2633** a second process is holding a reserved lock that it is trying 2634** to promote to an exclusive lock. The first process cannot proceed 2635** because it is blocked by the second and the second process cannot 2636** proceed because it is blocked by the first. If both processes 2637** invoke the busy handlers, neither will make any progress. Therefore, 2638** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2639** will induce the first process to release its read lock and allow 2640** the second process to proceed. 2641** 2642** ^The default busy callback is NULL. 2643** 2644** ^(There can only be a single busy handler defined for each 2645** [database connection]. Setting a new busy handler clears any 2646** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2647** or evaluating [PRAGMA busy_timeout=N] will change the 2648** busy handler and thus clear any previously set busy handler. 2649** 2650** The busy callback should not take any actions which modify the 2651** database connection that invoked the busy handler. In other words, 2652** the busy handler is not reentrant. Any such actions 2653** result in undefined behavior. 2654** 2655** A busy handler must not close the database connection 2656** or [prepared statement] that invoked the busy handler. 2657*/ 2658int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2659 2660/* 2661** CAPI3REF: Set A Busy Timeout 2662** METHOD: sqlite3 2663** 2664** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2665** for a specified amount of time when a table is locked. ^The handler 2666** will sleep multiple times until at least "ms" milliseconds of sleeping 2667** have accumulated. ^After at least "ms" milliseconds of sleeping, 2668** the handler returns 0 which causes [sqlite3_step()] to return 2669** [SQLITE_BUSY]. 2670** 2671** ^Calling this routine with an argument less than or equal to zero 2672** turns off all busy handlers. 2673** 2674** ^(There can only be a single busy handler for a particular 2675** [database connection] at any given moment. If another busy handler 2676** was defined (using [sqlite3_busy_handler()]) prior to calling 2677** this routine, that other busy handler is cleared.)^ 2678** 2679** See also: [PRAGMA busy_timeout] 2680*/ 2681int sqlite3_busy_timeout(sqlite3*, int ms); 2682 2683/* 2684** CAPI3REF: Convenience Routines For Running Queries 2685** METHOD: sqlite3 2686** 2687** This is a legacy interface that is preserved for backwards compatibility. 2688** Use of this interface is not recommended. 2689** 2690** Definition: A <b>result table</b> is memory data structure created by the 2691** [sqlite3_get_table()] interface. A result table records the 2692** complete query results from one or more queries. 2693** 2694** The table conceptually has a number of rows and columns. But 2695** these numbers are not part of the result table itself. These 2696** numbers are obtained separately. Let N be the number of rows 2697** and M be the number of columns. 2698** 2699** A result table is an array of pointers to zero-terminated UTF-8 strings. 2700** There are (N+1)*M elements in the array. The first M pointers point 2701** to zero-terminated strings that contain the names of the columns. 2702** The remaining entries all point to query results. NULL values result 2703** in NULL pointers. All other values are in their UTF-8 zero-terminated 2704** string representation as returned by [sqlite3_column_text()]. 2705** 2706** A result table might consist of one or more memory allocations. 2707** It is not safe to pass a result table directly to [sqlite3_free()]. 2708** A result table should be deallocated using [sqlite3_free_table()]. 2709** 2710** ^(As an example of the result table format, suppose a query result 2711** is as follows: 2712** 2713** <blockquote><pre> 2714** Name | Age 2715** ----------------------- 2716** Alice | 43 2717** Bob | 28 2718** Cindy | 21 2719** </pre></blockquote> 2720** 2721** There are two columns (M==2) and three rows (N==3). Thus the 2722** result table has 8 entries. Suppose the result table is stored 2723** in an array named azResult. Then azResult holds this content: 2724** 2725** <blockquote><pre> 2726** azResult[0] = "Name"; 2727** azResult[1] = "Age"; 2728** azResult[2] = "Alice"; 2729** azResult[3] = "43"; 2730** azResult[4] = "Bob"; 2731** azResult[5] = "28"; 2732** azResult[6] = "Cindy"; 2733** azResult[7] = "21"; 2734** </pre></blockquote>)^ 2735** 2736** ^The sqlite3_get_table() function evaluates one or more 2737** semicolon-separated SQL statements in the zero-terminated UTF-8 2738** string of its 2nd parameter and returns a result table to the 2739** pointer given in its 3rd parameter. 2740** 2741** After the application has finished with the result from sqlite3_get_table(), 2742** it must pass the result table pointer to sqlite3_free_table() in order to 2743** release the memory that was malloced. Because of the way the 2744** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2745** function must not try to call [sqlite3_free()] directly. Only 2746** [sqlite3_free_table()] is able to release the memory properly and safely. 2747** 2748** The sqlite3_get_table() interface is implemented as a wrapper around 2749** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2750** to any internal data structures of SQLite. It uses only the public 2751** interface defined here. As a consequence, errors that occur in the 2752** wrapper layer outside of the internal [sqlite3_exec()] call are not 2753** reflected in subsequent calls to [sqlite3_errcode()] or 2754** [sqlite3_errmsg()]. 2755*/ 2756int sqlite3_get_table( 2757 sqlite3 *db, /* An open database */ 2758 const char *zSql, /* SQL to be evaluated */ 2759 char ***pazResult, /* Results of the query */ 2760 int *pnRow, /* Number of result rows written here */ 2761 int *pnColumn, /* Number of result columns written here */ 2762 char **pzErrmsg /* Error msg written here */ 2763); 2764void sqlite3_free_table(char **result); 2765 2766/* 2767** CAPI3REF: Formatted String Printing Functions 2768** 2769** These routines are work-alikes of the "printf()" family of functions 2770** from the standard C library. 2771** These routines understand most of the common formatting options from 2772** the standard library printf() 2773** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2774** See the [built-in printf()] documentation for details. 2775** 2776** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2777** results into memory obtained from [sqlite3_malloc64()]. 2778** The strings returned by these two routines should be 2779** released by [sqlite3_free()]. ^Both routines return a 2780** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2781** memory to hold the resulting string. 2782** 2783** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2784** the standard C library. The result is written into the 2785** buffer supplied as the second parameter whose size is given by 2786** the first parameter. Note that the order of the 2787** first two parameters is reversed from snprintf().)^ This is an 2788** historical accident that cannot be fixed without breaking 2789** backwards compatibility. ^(Note also that sqlite3_snprintf() 2790** returns a pointer to its buffer instead of the number of 2791** characters actually written into the buffer.)^ We admit that 2792** the number of characters written would be a more useful return 2793** value but we cannot change the implementation of sqlite3_snprintf() 2794** now without breaking compatibility. 2795** 2796** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2797** guarantees that the buffer is always zero-terminated. ^The first 2798** parameter "n" is the total size of the buffer, including space for 2799** the zero terminator. So the longest string that can be completely 2800** written will be n-1 characters. 2801** 2802** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2803** 2804** See also: [built-in printf()], [printf() SQL function] 2805*/ 2806char *sqlite3_mprintf(const char*,...); 2807char *sqlite3_vmprintf(const char*, va_list); 2808char *sqlite3_snprintf(int,char*,const char*, ...); 2809char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2810 2811/* 2812** CAPI3REF: Memory Allocation Subsystem 2813** 2814** The SQLite core uses these three routines for all of its own 2815** internal memory allocation needs. "Core" in the previous sentence 2816** does not include operating-system specific [VFS] implementation. The 2817** Windows VFS uses native malloc() and free() for some operations. 2818** 2819** ^The sqlite3_malloc() routine returns a pointer to a block 2820** of memory at least N bytes in length, where N is the parameter. 2821** ^If sqlite3_malloc() is unable to obtain sufficient free 2822** memory, it returns a NULL pointer. ^If the parameter N to 2823** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2824** a NULL pointer. 2825** 2826** ^The sqlite3_malloc64(N) routine works just like 2827** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2828** of a signed 32-bit integer. 2829** 2830** ^Calling sqlite3_free() with a pointer previously returned 2831** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2832** that it might be reused. ^The sqlite3_free() routine is 2833** a no-op if is called with a NULL pointer. Passing a NULL pointer 2834** to sqlite3_free() is harmless. After being freed, memory 2835** should neither be read nor written. Even reading previously freed 2836** memory might result in a segmentation fault or other severe error. 2837** Memory corruption, a segmentation fault, or other severe error 2838** might result if sqlite3_free() is called with a non-NULL pointer that 2839** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2840** 2841** ^The sqlite3_realloc(X,N) interface attempts to resize a 2842** prior memory allocation X to be at least N bytes. 2843** ^If the X parameter to sqlite3_realloc(X,N) 2844** is a NULL pointer then its behavior is identical to calling 2845** sqlite3_malloc(N). 2846** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2847** negative then the behavior is exactly the same as calling 2848** sqlite3_free(X). 2849** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2850** of at least N bytes in size or NULL if insufficient memory is available. 2851** ^If M is the size of the prior allocation, then min(N,M) bytes 2852** of the prior allocation are copied into the beginning of buffer returned 2853** by sqlite3_realloc(X,N) and the prior allocation is freed. 2854** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2855** prior allocation is not freed. 2856** 2857** ^The sqlite3_realloc64(X,N) interfaces works the same as 2858** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2859** of a 32-bit signed integer. 2860** 2861** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2862** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2863** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2864** ^The value returned by sqlite3_msize(X) might be larger than the number 2865** of bytes requested when X was allocated. ^If X is a NULL pointer then 2866** sqlite3_msize(X) returns zero. If X points to something that is not 2867** the beginning of memory allocation, or if it points to a formerly 2868** valid memory allocation that has now been freed, then the behavior 2869** of sqlite3_msize(X) is undefined and possibly harmful. 2870** 2871** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2872** sqlite3_malloc64(), and sqlite3_realloc64() 2873** is always aligned to at least an 8 byte boundary, or to a 2874** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2875** option is used. 2876** 2877** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2878** must be either NULL or else pointers obtained from a prior 2879** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2880** not yet been released. 2881** 2882** The application must not read or write any part of 2883** a block of memory after it has been released using 2884** [sqlite3_free()] or [sqlite3_realloc()]. 2885*/ 2886void *sqlite3_malloc(int); 2887void *sqlite3_malloc64(sqlite3_uint64); 2888void *sqlite3_realloc(void*, int); 2889void *sqlite3_realloc64(void*, sqlite3_uint64); 2890void sqlite3_free(void*); 2891sqlite3_uint64 sqlite3_msize(void*); 2892 2893/* 2894** CAPI3REF: Memory Allocator Statistics 2895** 2896** SQLite provides these two interfaces for reporting on the status 2897** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2898** routines, which form the built-in memory allocation subsystem. 2899** 2900** ^The [sqlite3_memory_used()] routine returns the number of bytes 2901** of memory currently outstanding (malloced but not freed). 2902** ^The [sqlite3_memory_highwater()] routine returns the maximum 2903** value of [sqlite3_memory_used()] since the high-water mark 2904** was last reset. ^The values returned by [sqlite3_memory_used()] and 2905** [sqlite3_memory_highwater()] include any overhead 2906** added by SQLite in its implementation of [sqlite3_malloc()], 2907** but not overhead added by the any underlying system library 2908** routines that [sqlite3_malloc()] may call. 2909** 2910** ^The memory high-water mark is reset to the current value of 2911** [sqlite3_memory_used()] if and only if the parameter to 2912** [sqlite3_memory_highwater()] is true. ^The value returned 2913** by [sqlite3_memory_highwater(1)] is the high-water mark 2914** prior to the reset. 2915*/ 2916sqlite3_int64 sqlite3_memory_used(void); 2917sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2918 2919/* 2920** CAPI3REF: Pseudo-Random Number Generator 2921** 2922** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2923** select random [ROWID | ROWIDs] when inserting new records into a table that 2924** already uses the largest possible [ROWID]. The PRNG is also used for 2925** the built-in random() and randomblob() SQL functions. This interface allows 2926** applications to access the same PRNG for other purposes. 2927** 2928** ^A call to this routine stores N bytes of randomness into buffer P. 2929** ^The P parameter can be a NULL pointer. 2930** 2931** ^If this routine has not been previously called or if the previous 2932** call had N less than one or a NULL pointer for P, then the PRNG is 2933** seeded using randomness obtained from the xRandomness method of 2934** the default [sqlite3_vfs] object. 2935** ^If the previous call to this routine had an N of 1 or more and a 2936** non-NULL P then the pseudo-randomness is generated 2937** internally and without recourse to the [sqlite3_vfs] xRandomness 2938** method. 2939*/ 2940void sqlite3_randomness(int N, void *P); 2941 2942/* 2943** CAPI3REF: Compile-Time Authorization Callbacks 2944** METHOD: sqlite3 2945** KEYWORDS: {authorizer callback} 2946** 2947** ^This routine registers an authorizer callback with a particular 2948** [database connection], supplied in the first argument. 2949** ^The authorizer callback is invoked as SQL statements are being compiled 2950** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2951** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2952** and [sqlite3_prepare16_v3()]. ^At various 2953** points during the compilation process, as logic is being created 2954** to perform various actions, the authorizer callback is invoked to 2955** see if those actions are allowed. ^The authorizer callback should 2956** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2957** specific action but allow the SQL statement to continue to be 2958** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2959** rejected with an error. ^If the authorizer callback returns 2960** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2961** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2962** the authorizer will fail with an error message. 2963** 2964** When the callback returns [SQLITE_OK], that means the operation 2965** requested is ok. ^When the callback returns [SQLITE_DENY], the 2966** [sqlite3_prepare_v2()] or equivalent call that triggered the 2967** authorizer will fail with an error message explaining that 2968** access is denied. 2969** 2970** ^The first parameter to the authorizer callback is a copy of the third 2971** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2972** to the callback is an integer [SQLITE_COPY | action code] that specifies 2973** the particular action to be authorized. ^The third through sixth parameters 2974** to the callback are either NULL pointers or zero-terminated strings 2975** that contain additional details about the action to be authorized. 2976** Applications must always be prepared to encounter a NULL pointer in any 2977** of the third through the sixth parameters of the authorization callback. 2978** 2979** ^If the action code is [SQLITE_READ] 2980** and the callback returns [SQLITE_IGNORE] then the 2981** [prepared statement] statement is constructed to substitute 2982** a NULL value in place of the table column that would have 2983** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2984** return can be used to deny an untrusted user access to individual 2985** columns of a table. 2986** ^When a table is referenced by a [SELECT] but no column values are 2987** extracted from that table (for example in a query like 2988** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2989** is invoked once for that table with a column name that is an empty string. 2990** ^If the action code is [SQLITE_DELETE] and the callback returns 2991** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2992** [truncate optimization] is disabled and all rows are deleted individually. 2993** 2994** An authorizer is used when [sqlite3_prepare | preparing] 2995** SQL statements from an untrusted source, to ensure that the SQL statements 2996** do not try to access data they are not allowed to see, or that they do not 2997** try to execute malicious statements that damage the database. For 2998** example, an application may allow a user to enter arbitrary 2999** SQL queries for evaluation by a database. But the application does 3000** not want the user to be able to make arbitrary changes to the 3001** database. An authorizer could then be put in place while the 3002** user-entered SQL is being [sqlite3_prepare | prepared] that 3003** disallows everything except [SELECT] statements. 3004** 3005** Applications that need to process SQL from untrusted sources 3006** might also consider lowering resource limits using [sqlite3_limit()] 3007** and limiting database size using the [max_page_count] [PRAGMA] 3008** in addition to using an authorizer. 3009** 3010** ^(Only a single authorizer can be in place on a database connection 3011** at a time. Each call to sqlite3_set_authorizer overrides the 3012** previous call.)^ ^Disable the authorizer by installing a NULL callback. 3013** The authorizer is disabled by default. 3014** 3015** The authorizer callback must not do anything that will modify 3016** the database connection that invoked the authorizer callback. 3017** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3018** database connections for the meaning of "modify" in this paragraph. 3019** 3020** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 3021** statement might be re-prepared during [sqlite3_step()] due to a 3022** schema change. Hence, the application should ensure that the 3023** correct authorizer callback remains in place during the [sqlite3_step()]. 3024** 3025** ^Note that the authorizer callback is invoked only during 3026** [sqlite3_prepare()] or its variants. Authorization is not 3027** performed during statement evaluation in [sqlite3_step()], unless 3028** as stated in the previous paragraph, sqlite3_step() invokes 3029** sqlite3_prepare_v2() to reprepare a statement after a schema change. 3030*/ 3031int sqlite3_set_authorizer( 3032 sqlite3*, 3033 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 3034 void *pUserData 3035); 3036 3037/* 3038** CAPI3REF: Authorizer Return Codes 3039** 3040** The [sqlite3_set_authorizer | authorizer callback function] must 3041** return either [SQLITE_OK] or one of these two constants in order 3042** to signal SQLite whether or not the action is permitted. See the 3043** [sqlite3_set_authorizer | authorizer documentation] for additional 3044** information. 3045** 3046** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 3047** returned from the [sqlite3_vtab_on_conflict()] interface. 3048*/ 3049#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 3050#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 3051 3052/* 3053** CAPI3REF: Authorizer Action Codes 3054** 3055** The [sqlite3_set_authorizer()] interface registers a callback function 3056** that is invoked to authorize certain SQL statement actions. The 3057** second parameter to the callback is an integer code that specifies 3058** what action is being authorized. These are the integer action codes that 3059** the authorizer callback may be passed. 3060** 3061** These action code values signify what kind of operation is to be 3062** authorized. The 3rd and 4th parameters to the authorization 3063** callback function will be parameters or NULL depending on which of these 3064** codes is used as the second parameter. ^(The 5th parameter to the 3065** authorizer callback is the name of the database ("main", "temp", 3066** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 3067** is the name of the inner-most trigger or view that is responsible for 3068** the access attempt or NULL if this access attempt is directly from 3069** top-level SQL code. 3070*/ 3071/******************************************* 3rd ************ 4th ***********/ 3072#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 3073#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 3074#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 3075#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 3076#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 3077#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 3078#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 3079#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 3080#define SQLITE_DELETE 9 /* Table Name NULL */ 3081#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 3082#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 3083#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 3084#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 3085#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 3086#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 3087#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 3088#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 3089#define SQLITE_INSERT 18 /* Table Name NULL */ 3090#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 3091#define SQLITE_READ 20 /* Table Name Column Name */ 3092#define SQLITE_SELECT 21 /* NULL NULL */ 3093#define SQLITE_TRANSACTION 22 /* Operation NULL */ 3094#define SQLITE_UPDATE 23 /* Table Name Column Name */ 3095#define SQLITE_ATTACH 24 /* Filename NULL */ 3096#define SQLITE_DETACH 25 /* Database Name NULL */ 3097#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 3098#define SQLITE_REINDEX 27 /* Index Name NULL */ 3099#define SQLITE_ANALYZE 28 /* Table Name NULL */ 3100#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 3101#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 3102#define SQLITE_FUNCTION 31 /* NULL Function Name */ 3103#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 3104#define SQLITE_COPY 0 /* No longer used */ 3105#define SQLITE_RECURSIVE 33 /* NULL NULL */ 3106 3107/* 3108** CAPI3REF: Tracing And Profiling Functions 3109** METHOD: sqlite3 3110** 3111** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 3112** instead of the routines described here. 3113** 3114** These routines register callback functions that can be used for 3115** tracing and profiling the execution of SQL statements. 3116** 3117** ^The callback function registered by sqlite3_trace() is invoked at 3118** various times when an SQL statement is being run by [sqlite3_step()]. 3119** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 3120** SQL statement text as the statement first begins executing. 3121** ^(Additional sqlite3_trace() callbacks might occur 3122** as each triggered subprogram is entered. The callbacks for triggers 3123** contain a UTF-8 SQL comment that identifies the trigger.)^ 3124** 3125** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 3126** the length of [bound parameter] expansion in the output of sqlite3_trace(). 3127** 3128** ^The callback function registered by sqlite3_profile() is invoked 3129** as each SQL statement finishes. ^The profile callback contains 3130** the original statement text and an estimate of wall-clock time 3131** of how long that statement took to run. ^The profile callback 3132** time is in units of nanoseconds, however the current implementation 3133** is only capable of millisecond resolution so the six least significant 3134** digits in the time are meaningless. Future versions of SQLite 3135** might provide greater resolution on the profiler callback. Invoking 3136** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the 3137** profile callback. 3138*/ 3139SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 3140 void(*xTrace)(void*,const char*), void*); 3141SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 3142 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 3143 3144/* 3145** CAPI3REF: SQL Trace Event Codes 3146** KEYWORDS: SQLITE_TRACE 3147** 3148** These constants identify classes of events that can be monitored 3149** using the [sqlite3_trace_v2()] tracing logic. The M argument 3150** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 3151** the following constants. ^The first argument to the trace callback 3152** is one of the following constants. 3153** 3154** New tracing constants may be added in future releases. 3155** 3156** ^A trace callback has four arguments: xCallback(T,C,P,X). 3157** ^The T argument is one of the integer type codes above. 3158** ^The C argument is a copy of the context pointer passed in as the 3159** fourth argument to [sqlite3_trace_v2()]. 3160** The P and X arguments are pointers whose meanings depend on T. 3161** 3162** <dl> 3163** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 3164** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 3165** first begins running and possibly at other times during the 3166** execution of the prepared statement, such as at the start of each 3167** trigger subprogram. ^The P argument is a pointer to the 3168** [prepared statement]. ^The X argument is a pointer to a string which 3169** is the unexpanded SQL text of the prepared statement or an SQL comment 3170** that indicates the invocation of a trigger. ^The callback can compute 3171** the same text that would have been returned by the legacy [sqlite3_trace()] 3172** interface by using the X argument when X begins with "--" and invoking 3173** [sqlite3_expanded_sql(P)] otherwise. 3174** 3175** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 3176** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 3177** information as is provided by the [sqlite3_profile()] callback. 3178** ^The P argument is a pointer to the [prepared statement] and the 3179** X argument points to a 64-bit integer which is the estimated of 3180** the number of nanosecond that the prepared statement took to run. 3181** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 3182** 3183** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 3184** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 3185** statement generates a single row of result. 3186** ^The P argument is a pointer to the [prepared statement] and the 3187** X argument is unused. 3188** 3189** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 3190** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 3191** connection closes. 3192** ^The P argument is a pointer to the [database connection] object 3193** and the X argument is unused. 3194** </dl> 3195*/ 3196#define SQLITE_TRACE_STMT 0x01 3197#define SQLITE_TRACE_PROFILE 0x02 3198#define SQLITE_TRACE_ROW 0x04 3199#define SQLITE_TRACE_CLOSE 0x08 3200 3201/* 3202** CAPI3REF: SQL Trace Hook 3203** METHOD: sqlite3 3204** 3205** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3206** function X against [database connection] D, using property mask M 3207** and context pointer P. ^If the X callback is 3208** NULL or if the M mask is zero, then tracing is disabled. The 3209** M argument should be the bitwise OR-ed combination of 3210** zero or more [SQLITE_TRACE] constants. 3211** 3212** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3213** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3214** 3215** ^The X callback is invoked whenever any of the events identified by 3216** mask M occur. ^The integer return value from the callback is currently 3217** ignored, though this may change in future releases. Callback 3218** implementations should return zero to ensure future compatibility. 3219** 3220** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3221** ^The T argument is one of the [SQLITE_TRACE] 3222** constants to indicate why the callback was invoked. 3223** ^The C argument is a copy of the context pointer. 3224** The P and X arguments are pointers whose meanings depend on T. 3225** 3226** The sqlite3_trace_v2() interface is intended to replace the legacy 3227** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3228** are deprecated. 3229*/ 3230int sqlite3_trace_v2( 3231 sqlite3*, 3232 unsigned uMask, 3233 int(*xCallback)(unsigned,void*,void*,void*), 3234 void *pCtx 3235); 3236 3237/* 3238** CAPI3REF: Query Progress Callbacks 3239** METHOD: sqlite3 3240** 3241** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3242** function X to be invoked periodically during long running calls to 3243** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3244** database connection D. An example use for this 3245** interface is to keep a GUI updated during a large query. 3246** 3247** ^The parameter P is passed through as the only parameter to the 3248** callback function X. ^The parameter N is the approximate number of 3249** [virtual machine instructions] that are evaluated between successive 3250** invocations of the callback X. ^If N is less than one then the progress 3251** handler is disabled. 3252** 3253** ^Only a single progress handler may be defined at one time per 3254** [database connection]; setting a new progress handler cancels the 3255** old one. ^Setting parameter X to NULL disables the progress handler. 3256** ^The progress handler is also disabled by setting N to a value less 3257** than 1. 3258** 3259** ^If the progress callback returns non-zero, the operation is 3260** interrupted. This feature can be used to implement a 3261** "Cancel" button on a GUI progress dialog box. 3262** 3263** The progress handler callback must not do anything that will modify 3264** the database connection that invoked the progress handler. 3265** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3266** database connections for the meaning of "modify" in this paragraph. 3267** 3268*/ 3269void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3270 3271/* 3272** CAPI3REF: Opening A New Database Connection 3273** CONSTRUCTOR: sqlite3 3274** 3275** ^These routines open an SQLite database file as specified by the 3276** filename argument. ^The filename argument is interpreted as UTF-8 for 3277** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3278** order for sqlite3_open16(). ^(A [database connection] handle is usually 3279** returned in *ppDb, even if an error occurs. The only exception is that 3280** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3281** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3282** object.)^ ^(If the database is opened (and/or created) successfully, then 3283** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3284** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3285** an English language description of the error following a failure of any 3286** of the sqlite3_open() routines. 3287** 3288** ^The default encoding will be UTF-8 for databases created using 3289** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3290** created using sqlite3_open16() will be UTF-16 in the native byte order. 3291** 3292** Whether or not an error occurs when it is opened, resources 3293** associated with the [database connection] handle should be released by 3294** passing it to [sqlite3_close()] when it is no longer required. 3295** 3296** The sqlite3_open_v2() interface works like sqlite3_open() 3297** except that it accepts two additional parameters for additional control 3298** over the new database connection. ^(The flags parameter to 3299** sqlite3_open_v2() must include, at a minimum, one of the following 3300** three flag combinations:)^ 3301** 3302** <dl> 3303** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3304** <dd>The database is opened in read-only mode. If the database does not 3305** already exist, an error is returned.</dd>)^ 3306** 3307** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3308** <dd>The database is opened for reading and writing if possible, or reading 3309** only if the file is write protected by the operating system. In either 3310** case the database must already exist, otherwise an error is returned.</dd>)^ 3311** 3312** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3313** <dd>The database is opened for reading and writing, and is created if 3314** it does not already exist. This is the behavior that is always used for 3315** sqlite3_open() and sqlite3_open16().</dd>)^ 3316** </dl> 3317** 3318** In addition to the required flags, the following optional flags are 3319** also supported: 3320** 3321** <dl> 3322** ^(<dt>[SQLITE_OPEN_URI]</dt> 3323** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^ 3324** 3325** ^(<dt>[SQLITE_OPEN_MEMORY]</dt> 3326** <dd>The database will be opened as an in-memory database. The database 3327** is named by the "filename" argument for the purposes of cache-sharing, 3328** if shared cache mode is enabled, but the "filename" is otherwise ignored. 3329** </dd>)^ 3330** 3331** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt> 3332** <dd>The new database connection will use the "multi-thread" 3333** [threading mode].)^ This means that separate threads are allowed 3334** to use SQLite at the same time, as long as each thread is using 3335** a different [database connection]. 3336** 3337** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt> 3338** <dd>The new database connection will use the "serialized" 3339** [threading mode].)^ This means the multiple threads can safely 3340** attempt to use the same database connection at the same time. 3341** (Mutexes will block any actual concurrency, but in this mode 3342** there is no harm in trying.) 3343** 3344** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt> 3345** <dd>The database is opened [shared cache] enabled, overriding 3346** the default shared cache setting provided by 3347** [sqlite3_enable_shared_cache()].)^ 3348** 3349** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt> 3350** <dd>The database is opened [shared cache] disabled, overriding 3351** the default shared cache setting provided by 3352** [sqlite3_enable_shared_cache()].)^ 3353** 3354** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt> 3355** <dd>The database filename is not allowed to be a symbolic link</dd> 3356** </dl>)^ 3357** 3358** If the 3rd parameter to sqlite3_open_v2() is not one of the 3359** required combinations shown above optionally combined with other 3360** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3361** then the behavior is undefined. 3362** 3363** ^The fourth parameter to sqlite3_open_v2() is the name of the 3364** [sqlite3_vfs] object that defines the operating system interface that 3365** the new database connection should use. ^If the fourth parameter is 3366** a NULL pointer then the default [sqlite3_vfs] object is used. 3367** 3368** ^If the filename is ":memory:", then a private, temporary in-memory database 3369** is created for the connection. ^This in-memory database will vanish when 3370** the database connection is closed. Future versions of SQLite might 3371** make use of additional special filenames that begin with the ":" character. 3372** It is recommended that when a database filename actually does begin with 3373** a ":" character you should prefix the filename with a pathname such as 3374** "./" to avoid ambiguity. 3375** 3376** ^If the filename is an empty string, then a private, temporary 3377** on-disk database will be created. ^This private database will be 3378** automatically deleted as soon as the database connection is closed. 3379** 3380** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3381** 3382** ^If [URI filename] interpretation is enabled, and the filename argument 3383** begins with "file:", then the filename is interpreted as a URI. ^URI 3384** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3385** set in the third argument to sqlite3_open_v2(), or if it has 3386** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3387** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3388** URI filename interpretation is turned off 3389** by default, but future releases of SQLite might enable URI filename 3390** interpretation by default. See "[URI filenames]" for additional 3391** information. 3392** 3393** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3394** authority, then it must be either an empty string or the string 3395** "localhost". ^If the authority is not an empty string or "localhost", an 3396** error is returned to the caller. ^The fragment component of a URI, if 3397** present, is ignored. 3398** 3399** ^SQLite uses the path component of the URI as the name of the disk file 3400** which contains the database. ^If the path begins with a '/' character, 3401** then it is interpreted as an absolute path. ^If the path does not begin 3402** with a '/' (meaning that the authority section is omitted from the URI) 3403** then the path is interpreted as a relative path. 3404** ^(On windows, the first component of an absolute path 3405** is a drive specification (e.g. "C:").)^ 3406** 3407** [[core URI query parameters]] 3408** The query component of a URI may contain parameters that are interpreted 3409** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3410** SQLite and its built-in [VFSes] interpret the 3411** following query parameters: 3412** 3413** <ul> 3414** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3415** a VFS object that provides the operating system interface that should 3416** be used to access the database file on disk. ^If this option is set to 3417** an empty string the default VFS object is used. ^Specifying an unknown 3418** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3419** present, then the VFS specified by the option takes precedence over 3420** the value passed as the fourth parameter to sqlite3_open_v2(). 3421** 3422** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3423** "rwc", or "memory". Attempting to set it to any other value is 3424** an error)^. 3425** ^If "ro" is specified, then the database is opened for read-only 3426** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3427** third argument to sqlite3_open_v2(). ^If the mode option is set to 3428** "rw", then the database is opened for read-write (but not create) 3429** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3430** been set. ^Value "rwc" is equivalent to setting both 3431** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3432** set to "memory" then a pure [in-memory database] that never reads 3433** or writes from disk is used. ^It is an error to specify a value for 3434** the mode parameter that is less restrictive than that specified by 3435** the flags passed in the third parameter to sqlite3_open_v2(). 3436** 3437** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3438** "private". ^Setting it to "shared" is equivalent to setting the 3439** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3440** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3441** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3442** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3443** a URI filename, its value overrides any behavior requested by setting 3444** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3445** 3446** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3447** [powersafe overwrite] property does or does not apply to the 3448** storage media on which the database file resides. 3449** 3450** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3451** which if set disables file locking in rollback journal modes. This 3452** is useful for accessing a database on a filesystem that does not 3453** support locking. Caution: Database corruption might result if two 3454** or more processes write to the same database and any one of those 3455** processes uses nolock=1. 3456** 3457** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3458** parameter that indicates that the database file is stored on 3459** read-only media. ^When immutable is set, SQLite assumes that the 3460** database file cannot be changed, even by a process with higher 3461** privilege, and so the database is opened read-only and all locking 3462** and change detection is disabled. Caution: Setting the immutable 3463** property on a database file that does in fact change can result 3464** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3465** See also: [SQLITE_IOCAP_IMMUTABLE]. 3466** 3467** </ul> 3468** 3469** ^Specifying an unknown parameter in the query component of a URI is not an 3470** error. Future versions of SQLite might understand additional query 3471** parameters. See "[query parameters with special meaning to SQLite]" for 3472** additional information. 3473** 3474** [[URI filename examples]] <h3>URI filename examples</h3> 3475** 3476** <table border="1" align=center cellpadding=5> 3477** <tr><th> URI filenames <th> Results 3478** <tr><td> file:data.db <td> 3479** Open the file "data.db" in the current directory. 3480** <tr><td> file:/home/fred/data.db<br> 3481** file:///home/fred/data.db <br> 3482** file://localhost/home/fred/data.db <br> <td> 3483** Open the database file "/home/fred/data.db". 3484** <tr><td> file://darkstar/home/fred/data.db <td> 3485** An error. "darkstar" is not a recognized authority. 3486** <tr><td style="white-space:nowrap"> 3487** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3488** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3489** C:. Note that the %20 escaping in this example is not strictly 3490** necessary - space characters can be used literally 3491** in URI filenames. 3492** <tr><td> file:data.db?mode=ro&cache=private <td> 3493** Open file "data.db" in the current directory for read-only access. 3494** Regardless of whether or not shared-cache mode is enabled by 3495** default, use a private cache. 3496** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3497** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3498** that uses dot-files in place of posix advisory locking. 3499** <tr><td> file:data.db?mode=readonly <td> 3500** An error. "readonly" is not a valid option for the "mode" parameter. 3501** </table> 3502** 3503** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3504** query components of a URI. A hexadecimal escape sequence consists of a 3505** percent sign - "%" - followed by exactly two hexadecimal digits 3506** specifying an octet value. ^Before the path or query components of a 3507** URI filename are interpreted, they are encoded using UTF-8 and all 3508** hexadecimal escape sequences replaced by a single byte containing the 3509** corresponding octet. If this process generates an invalid UTF-8 encoding, 3510** the results are undefined. 3511** 3512** <b>Note to Windows users:</b> The encoding used for the filename argument 3513** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3514** codepage is currently defined. Filenames containing international 3515** characters must be converted to UTF-8 prior to passing them into 3516** sqlite3_open() or sqlite3_open_v2(). 3517** 3518** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3519** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3520** features that require the use of temporary files may fail. 3521** 3522** See also: [sqlite3_temp_directory] 3523*/ 3524int sqlite3_open( 3525 const char *filename, /* Database filename (UTF-8) */ 3526 sqlite3 **ppDb /* OUT: SQLite db handle */ 3527); 3528int sqlite3_open16( 3529 const void *filename, /* Database filename (UTF-16) */ 3530 sqlite3 **ppDb /* OUT: SQLite db handle */ 3531); 3532int sqlite3_open_v2( 3533 const char *filename, /* Database filename (UTF-8) */ 3534 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3535 int flags, /* Flags */ 3536 const char *zVfs /* Name of VFS module to use */ 3537); 3538 3539/* 3540** CAPI3REF: Obtain Values For URI Parameters 3541** 3542** These are utility routines, useful to [VFS|custom VFS implementations], 3543** that check if a database file was a URI that contained a specific query 3544** parameter, and if so obtains the value of that query parameter. 3545** 3546** The first parameter to these interfaces (hereafter referred to 3547** as F) must be one of: 3548** <ul> 3549** <li> A database filename pointer created by the SQLite core and 3550** passed into the xOpen() method of a VFS implemention, or 3551** <li> A filename obtained from [sqlite3_db_filename()], or 3552** <li> A new filename constructed using [sqlite3_create_filename()]. 3553** </ul> 3554** If the F parameter is not one of the above, then the behavior is 3555** undefined and probably undesirable. Older versions of SQLite were 3556** more tolerant of invalid F parameters than newer versions. 3557** 3558** If F is a suitable filename (as described in the previous paragraph) 3559** and if P is the name of the query parameter, then 3560** sqlite3_uri_parameter(F,P) returns the value of the P 3561** parameter if it exists or a NULL pointer if P does not appear as a 3562** query parameter on F. If P is a query parameter of F and it 3563** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3564** a pointer to an empty string. 3565** 3566** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3567** parameter and returns true (1) or false (0) according to the value 3568** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3569** value of query parameter P is one of "yes", "true", or "on" in any 3570** case or if the value begins with a non-zero number. The 3571** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3572** query parameter P is one of "no", "false", or "off" in any case or 3573** if the value begins with a numeric zero. If P is not a query 3574** parameter on F or if the value of P does not match any of the 3575** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3576** 3577** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3578** 64-bit signed integer and returns that integer, or D if P does not 3579** exist. If the value of P is something other than an integer, then 3580** zero is returned. 3581** 3582** The sqlite3_uri_key(F,N) returns a pointer to the name (not 3583** the value) of the N-th query parameter for filename F, or a NULL 3584** pointer if N is less than zero or greater than the number of query 3585** parameters minus 1. The N value is zero-based so N should be 0 to obtain 3586** the name of the first query parameter, 1 for the second parameter, and 3587** so forth. 3588** 3589** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3590** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3591** is not a database file pathname pointer that the SQLite core passed 3592** into the xOpen VFS method, then the behavior of this routine is undefined 3593** and probably undesirable. 3594** 3595** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F 3596** parameter can also be the name of a rollback journal file or WAL file 3597** in addition to the main database file. Prior to version 3.31.0, these 3598** routines would only work if F was the name of the main database file. 3599** When the F parameter is the name of the rollback journal or WAL file, 3600** it has access to all the same query parameters as were found on the 3601** main database file. 3602** 3603** See the [URI filename] documentation for additional information. 3604*/ 3605const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3606int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3607sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3608const char *sqlite3_uri_key(const char *zFilename, int N); 3609 3610/* 3611** CAPI3REF: Translate filenames 3612** 3613** These routines are available to [VFS|custom VFS implementations] for 3614** translating filenames between the main database file, the journal file, 3615** and the WAL file. 3616** 3617** If F is the name of an sqlite database file, journal file, or WAL file 3618** passed by the SQLite core into the VFS, then sqlite3_filename_database(F) 3619** returns the name of the corresponding database file. 3620** 3621** If F is the name of an sqlite database file, journal file, or WAL file 3622** passed by the SQLite core into the VFS, or if F is a database filename 3623** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F) 3624** returns the name of the corresponding rollback journal file. 3625** 3626** If F is the name of an sqlite database file, journal file, or WAL file 3627** that was passed by the SQLite core into the VFS, or if F is a database 3628** filename obtained from [sqlite3_db_filename()], then 3629** sqlite3_filename_wal(F) returns the name of the corresponding 3630** WAL file. 3631** 3632** In all of the above, if F is not the name of a database, journal or WAL 3633** filename passed into the VFS from the SQLite core and F is not the 3634** return value from [sqlite3_db_filename()], then the result is 3635** undefined and is likely a memory access violation. 3636*/ 3637const char *sqlite3_filename_database(const char*); 3638const char *sqlite3_filename_journal(const char*); 3639const char *sqlite3_filename_wal(const char*); 3640 3641/* 3642** CAPI3REF: Database File Corresponding To A Journal 3643** 3644** ^If X is the name of a rollback or WAL-mode journal file that is 3645** passed into the xOpen method of [sqlite3_vfs], then 3646** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file] 3647** object that represents the main database file. 3648** 3649** This routine is intended for use in custom [VFS] implementations 3650** only. It is not a general-purpose interface. 3651** The argument sqlite3_file_object(X) must be a filename pointer that 3652** has been passed into [sqlite3_vfs].xOpen method where the 3653** flags parameter to xOpen contains one of the bits 3654** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL]. Any other use 3655** of this routine results in undefined and probably undesirable 3656** behavior. 3657*/ 3658sqlite3_file *sqlite3_database_file_object(const char*); 3659 3660/* 3661** CAPI3REF: Create and Destroy VFS Filenames 3662** 3663** These interfces are provided for use by [VFS shim] implementations and 3664** are not useful outside of that context. 3665** 3666** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of 3667** database filename D with corresponding journal file J and WAL file W and 3668** with N URI parameters key/values pairs in the array P. The result from 3669** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that 3670** is safe to pass to routines like: 3671** <ul> 3672** <li> [sqlite3_uri_parameter()], 3673** <li> [sqlite3_uri_boolean()], 3674** <li> [sqlite3_uri_int64()], 3675** <li> [sqlite3_uri_key()], 3676** <li> [sqlite3_filename_database()], 3677** <li> [sqlite3_filename_journal()], or 3678** <li> [sqlite3_filename_wal()]. 3679** </ul> 3680** If a memory allocation error occurs, sqlite3_create_filename() might 3681** return a NULL pointer. The memory obtained from sqlite3_create_filename(X) 3682** must be released by a corresponding call to sqlite3_free_filename(Y). 3683** 3684** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array 3685** of 2*N pointers to strings. Each pair of pointers in this array corresponds 3686** to a key and value for a query parameter. The P parameter may be a NULL 3687** pointer if N is zero. None of the 2*N pointers in the P array may be 3688** NULL pointers and key pointers should not be empty strings. 3689** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may 3690** be NULL pointers, though they can be empty strings. 3691** 3692** The sqlite3_free_filename(Y) routine releases a memory allocation 3693** previously obtained from sqlite3_create_filename(). Invoking 3694** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op. 3695** 3696** If the Y parameter to sqlite3_free_filename(Y) is anything other 3697** than a NULL pointer or a pointer previously acquired from 3698** sqlite3_create_filename(), then bad things such as heap 3699** corruption or segfaults may occur. The value Y should be 3700** used again after sqlite3_free_filename(Y) has been called. This means 3701** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y, 3702** then the corresponding [sqlite3_module.xClose() method should also be 3703** invoked prior to calling sqlite3_free_filename(Y). 3704*/ 3705char *sqlite3_create_filename( 3706 const char *zDatabase, 3707 const char *zJournal, 3708 const char *zWal, 3709 int nParam, 3710 const char **azParam 3711); 3712void sqlite3_free_filename(char*); 3713 3714/* 3715** CAPI3REF: Error Codes And Messages 3716** METHOD: sqlite3 3717** 3718** ^If the most recent sqlite3_* API call associated with 3719** [database connection] D failed, then the sqlite3_errcode(D) interface 3720** returns the numeric [result code] or [extended result code] for that 3721** API call. 3722** ^The sqlite3_extended_errcode() 3723** interface is the same except that it always returns the 3724** [extended result code] even when extended result codes are 3725** disabled. 3726** 3727** The values returned by sqlite3_errcode() and/or 3728** sqlite3_extended_errcode() might change with each API call. 3729** Except, there are some interfaces that are guaranteed to never 3730** change the value of the error code. The error-code preserving 3731** interfaces are: 3732** 3733** <ul> 3734** <li> sqlite3_errcode() 3735** <li> sqlite3_extended_errcode() 3736** <li> sqlite3_errmsg() 3737** <li> sqlite3_errmsg16() 3738** </ul> 3739** 3740** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3741** text that describes the error, as either UTF-8 or UTF-16 respectively. 3742** ^(Memory to hold the error message string is managed internally. 3743** The application does not need to worry about freeing the result. 3744** However, the error string might be overwritten or deallocated by 3745** subsequent calls to other SQLite interface functions.)^ 3746** 3747** ^The sqlite3_errstr() interface returns the English-language text 3748** that describes the [result code], as UTF-8. 3749** ^(Memory to hold the error message string is managed internally 3750** and must not be freed by the application)^. 3751** 3752** When the serialized [threading mode] is in use, it might be the 3753** case that a second error occurs on a separate thread in between 3754** the time of the first error and the call to these interfaces. 3755** When that happens, the second error will be reported since these 3756** interfaces always report the most recent result. To avoid 3757** this, each thread can obtain exclusive use of the [database connection] D 3758** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3759** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3760** all calls to the interfaces listed here are completed. 3761** 3762** If an interface fails with SQLITE_MISUSE, that means the interface 3763** was invoked incorrectly by the application. In that case, the 3764** error code and message may or may not be set. 3765*/ 3766int sqlite3_errcode(sqlite3 *db); 3767int sqlite3_extended_errcode(sqlite3 *db); 3768const char *sqlite3_errmsg(sqlite3*); 3769const void *sqlite3_errmsg16(sqlite3*); 3770const char *sqlite3_errstr(int); 3771 3772/* 3773** CAPI3REF: Prepared Statement Object 3774** KEYWORDS: {prepared statement} {prepared statements} 3775** 3776** An instance of this object represents a single SQL statement that 3777** has been compiled into binary form and is ready to be evaluated. 3778** 3779** Think of each SQL statement as a separate computer program. The 3780** original SQL text is source code. A prepared statement object 3781** is the compiled object code. All SQL must be converted into a 3782** prepared statement before it can be run. 3783** 3784** The life-cycle of a prepared statement object usually goes like this: 3785** 3786** <ol> 3787** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3788** <li> Bind values to [parameters] using the sqlite3_bind_*() 3789** interfaces. 3790** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3791** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3792** to step 2. Do this zero or more times. 3793** <li> Destroy the object using [sqlite3_finalize()]. 3794** </ol> 3795*/ 3796typedef struct sqlite3_stmt sqlite3_stmt; 3797 3798/* 3799** CAPI3REF: Run-time Limits 3800** METHOD: sqlite3 3801** 3802** ^(This interface allows the size of various constructs to be limited 3803** on a connection by connection basis. The first parameter is the 3804** [database connection] whose limit is to be set or queried. The 3805** second parameter is one of the [limit categories] that define a 3806** class of constructs to be size limited. The third parameter is the 3807** new limit for that construct.)^ 3808** 3809** ^If the new limit is a negative number, the limit is unchanged. 3810** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3811** [limits | hard upper bound] 3812** set at compile-time by a C preprocessor macro called 3813** [limits | SQLITE_MAX_<i>NAME</i>]. 3814** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3815** ^Attempts to increase a limit above its hard upper bound are 3816** silently truncated to the hard upper bound. 3817** 3818** ^Regardless of whether or not the limit was changed, the 3819** [sqlite3_limit()] interface returns the prior value of the limit. 3820** ^Hence, to find the current value of a limit without changing it, 3821** simply invoke this interface with the third parameter set to -1. 3822** 3823** Run-time limits are intended for use in applications that manage 3824** both their own internal database and also databases that are controlled 3825** by untrusted external sources. An example application might be a 3826** web browser that has its own databases for storing history and 3827** separate databases controlled by JavaScript applications downloaded 3828** off the Internet. The internal databases can be given the 3829** large, default limits. Databases managed by external sources can 3830** be given much smaller limits designed to prevent a denial of service 3831** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3832** interface to further control untrusted SQL. The size of the database 3833** created by an untrusted script can be contained using the 3834** [max_page_count] [PRAGMA]. 3835** 3836** New run-time limit categories may be added in future releases. 3837*/ 3838int sqlite3_limit(sqlite3*, int id, int newVal); 3839 3840/* 3841** CAPI3REF: Run-Time Limit Categories 3842** KEYWORDS: {limit category} {*limit categories} 3843** 3844** These constants define various performance limits 3845** that can be lowered at run-time using [sqlite3_limit()]. 3846** The synopsis of the meanings of the various limits is shown below. 3847** Additional information is available at [limits | Limits in SQLite]. 3848** 3849** <dl> 3850** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3851** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3852** 3853** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3854** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3855** 3856** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3857** <dd>The maximum number of columns in a table definition or in the 3858** result set of a [SELECT] or the maximum number of columns in an index 3859** or in an ORDER BY or GROUP BY clause.</dd>)^ 3860** 3861** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3862** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3863** 3864** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3865** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3866** 3867** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3868** <dd>The maximum number of instructions in a virtual machine program 3869** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3870** the equivalent tries to allocate space for more than this many opcodes 3871** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3872** 3873** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3874** <dd>The maximum number of arguments on a function.</dd>)^ 3875** 3876** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3877** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3878** 3879** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3880** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3881** <dd>The maximum length of the pattern argument to the [LIKE] or 3882** [GLOB] operators.</dd>)^ 3883** 3884** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3885** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3886** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3887** 3888** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3889** <dd>The maximum depth of recursion for triggers.</dd>)^ 3890** 3891** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3892** <dd>The maximum number of auxiliary worker threads that a single 3893** [prepared statement] may start.</dd>)^ 3894** </dl> 3895*/ 3896#define SQLITE_LIMIT_LENGTH 0 3897#define SQLITE_LIMIT_SQL_LENGTH 1 3898#define SQLITE_LIMIT_COLUMN 2 3899#define SQLITE_LIMIT_EXPR_DEPTH 3 3900#define SQLITE_LIMIT_COMPOUND_SELECT 4 3901#define SQLITE_LIMIT_VDBE_OP 5 3902#define SQLITE_LIMIT_FUNCTION_ARG 6 3903#define SQLITE_LIMIT_ATTACHED 7 3904#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3905#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3906#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3907#define SQLITE_LIMIT_WORKER_THREADS 11 3908 3909/* 3910** CAPI3REF: Prepare Flags 3911** 3912** These constants define various flags that can be passed into 3913** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3914** [sqlite3_prepare16_v3()] interfaces. 3915** 3916** New flags may be added in future releases of SQLite. 3917** 3918** <dl> 3919** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3920** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3921** that the prepared statement will be retained for a long time and 3922** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3923** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3924** be used just once or at most a few times and then destroyed using 3925** [sqlite3_finalize()] relatively soon. The current implementation acts 3926** on this hint by avoiding the use of [lookaside memory] so as not to 3927** deplete the limited store of lookaside memory. Future versions of 3928** SQLite may act on this hint differently. 3929** 3930** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt> 3931** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used 3932** to be required for any prepared statement that wanted to use the 3933** [sqlite3_normalized_sql()] interface. However, the 3934** [sqlite3_normalized_sql()] interface is now available to all 3935** prepared statements, regardless of whether or not they use this 3936** flag. 3937** 3938** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt> 3939** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler 3940** to return an error (error code SQLITE_ERROR) if the statement uses 3941** any virtual tables. 3942** </dl> 3943*/ 3944#define SQLITE_PREPARE_PERSISTENT 0x01 3945#define SQLITE_PREPARE_NORMALIZE 0x02 3946#define SQLITE_PREPARE_NO_VTAB 0x04 3947 3948/* 3949** CAPI3REF: Compiling An SQL Statement 3950** KEYWORDS: {SQL statement compiler} 3951** METHOD: sqlite3 3952** CONSTRUCTOR: sqlite3_stmt 3953** 3954** To execute an SQL statement, it must first be compiled into a byte-code 3955** program using one of these routines. Or, in other words, these routines 3956** are constructors for the [prepared statement] object. 3957** 3958** The preferred routine to use is [sqlite3_prepare_v2()]. The 3959** [sqlite3_prepare()] interface is legacy and should be avoided. 3960** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3961** for special purposes. 3962** 3963** The use of the UTF-8 interfaces is preferred, as SQLite currently 3964** does all parsing using UTF-8. The UTF-16 interfaces are provided 3965** as a convenience. The UTF-16 interfaces work by converting the 3966** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3967** 3968** The first argument, "db", is a [database connection] obtained from a 3969** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3970** [sqlite3_open16()]. The database connection must not have been closed. 3971** 3972** The second argument, "zSql", is the statement to be compiled, encoded 3973** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3974** and sqlite3_prepare_v3() 3975** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3976** and sqlite3_prepare16_v3() use UTF-16. 3977** 3978** ^If the nByte argument is negative, then zSql is read up to the 3979** first zero terminator. ^If nByte is positive, then it is the 3980** number of bytes read from zSql. ^If nByte is zero, then no prepared 3981** statement is generated. 3982** If the caller knows that the supplied string is nul-terminated, then 3983** there is a small performance advantage to passing an nByte parameter that 3984** is the number of bytes in the input string <i>including</i> 3985** the nul-terminator. 3986** 3987** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3988** past the end of the first SQL statement in zSql. These routines only 3989** compile the first statement in zSql, so *pzTail is left pointing to 3990** what remains uncompiled. 3991** 3992** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3993** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3994** to NULL. ^If the input text contains no SQL (if the input is an empty 3995** string or a comment) then *ppStmt is set to NULL. 3996** The calling procedure is responsible for deleting the compiled 3997** SQL statement using [sqlite3_finalize()] after it has finished with it. 3998** ppStmt may not be NULL. 3999** 4000** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 4001** otherwise an [error code] is returned. 4002** 4003** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 4004** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 4005** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 4006** are retained for backwards compatibility, but their use is discouraged. 4007** ^In the "vX" interfaces, the prepared statement 4008** that is returned (the [sqlite3_stmt] object) contains a copy of the 4009** original SQL text. This causes the [sqlite3_step()] interface to 4010** behave differently in three ways: 4011** 4012** <ol> 4013** <li> 4014** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 4015** always used to do, [sqlite3_step()] will automatically recompile the SQL 4016** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 4017** retries will occur before sqlite3_step() gives up and returns an error. 4018** </li> 4019** 4020** <li> 4021** ^When an error occurs, [sqlite3_step()] will return one of the detailed 4022** [error codes] or [extended error codes]. ^The legacy behavior was that 4023** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 4024** and the application would have to make a second call to [sqlite3_reset()] 4025** in order to find the underlying cause of the problem. With the "v2" prepare 4026** interfaces, the underlying reason for the error is returned immediately. 4027** </li> 4028** 4029** <li> 4030** ^If the specific value bound to a [parameter | host parameter] in the 4031** WHERE clause might influence the choice of query plan for a statement, 4032** then the statement will be automatically recompiled, as if there had been 4033** a schema change, on the first [sqlite3_step()] call following any change 4034** to the [sqlite3_bind_text | bindings] of that [parameter]. 4035** ^The specific value of a WHERE-clause [parameter] might influence the 4036** choice of query plan if the parameter is the left-hand side of a [LIKE] 4037** or [GLOB] operator or if the parameter is compared to an indexed column 4038** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled. 4039** </li> 4040** </ol> 4041** 4042** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 4043** the extra prepFlags parameter, which is a bit array consisting of zero or 4044** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 4045** sqlite3_prepare_v2() interface works exactly the same as 4046** sqlite3_prepare_v3() with a zero prepFlags parameter. 4047*/ 4048int sqlite3_prepare( 4049 sqlite3 *db, /* Database handle */ 4050 const char *zSql, /* SQL statement, UTF-8 encoded */ 4051 int nByte, /* Maximum length of zSql in bytes. */ 4052 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4053 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4054); 4055int sqlite3_prepare_v2( 4056 sqlite3 *db, /* Database handle */ 4057 const char *zSql, /* SQL statement, UTF-8 encoded */ 4058 int nByte, /* Maximum length of zSql in bytes. */ 4059 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4060 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4061); 4062int sqlite3_prepare_v3( 4063 sqlite3 *db, /* Database handle */ 4064 const char *zSql, /* SQL statement, UTF-8 encoded */ 4065 int nByte, /* Maximum length of zSql in bytes. */ 4066 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4067 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4068 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4069); 4070int sqlite3_prepare16( 4071 sqlite3 *db, /* Database handle */ 4072 const void *zSql, /* SQL statement, UTF-16 encoded */ 4073 int nByte, /* Maximum length of zSql in bytes. */ 4074 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4075 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4076); 4077int sqlite3_prepare16_v2( 4078 sqlite3 *db, /* Database handle */ 4079 const void *zSql, /* SQL statement, UTF-16 encoded */ 4080 int nByte, /* Maximum length of zSql in bytes. */ 4081 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4082 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4083); 4084int sqlite3_prepare16_v3( 4085 sqlite3 *db, /* Database handle */ 4086 const void *zSql, /* SQL statement, UTF-16 encoded */ 4087 int nByte, /* Maximum length of zSql in bytes. */ 4088 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4089 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4090 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4091); 4092 4093/* 4094** CAPI3REF: Retrieving Statement SQL 4095** METHOD: sqlite3_stmt 4096** 4097** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 4098** SQL text used to create [prepared statement] P if P was 4099** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 4100** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4101** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 4102** string containing the SQL text of prepared statement P with 4103** [bound parameters] expanded. 4104** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8 4105** string containing the normalized SQL text of prepared statement P. The 4106** semantics used to normalize a SQL statement are unspecified and subject 4107** to change. At a minimum, literal values will be replaced with suitable 4108** placeholders. 4109** 4110** ^(For example, if a prepared statement is created using the SQL 4111** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 4112** and parameter :xyz is unbound, then sqlite3_sql() will return 4113** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 4114** will return "SELECT 2345,NULL".)^ 4115** 4116** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 4117** is available to hold the result, or if the result would exceed the 4118** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 4119** 4120** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 4121** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 4122** option causes sqlite3_expanded_sql() to always return NULL. 4123** 4124** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P) 4125** are managed by SQLite and are automatically freed when the prepared 4126** statement is finalized. 4127** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 4128** is obtained from [sqlite3_malloc()] and must be free by the application 4129** by passing it to [sqlite3_free()]. 4130*/ 4131const char *sqlite3_sql(sqlite3_stmt *pStmt); 4132char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 4133const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt); 4134 4135/* 4136** CAPI3REF: Determine If An SQL Statement Writes The Database 4137** METHOD: sqlite3_stmt 4138** 4139** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 4140** and only if the [prepared statement] X makes no direct changes to 4141** the content of the database file. 4142** 4143** Note that [application-defined SQL functions] or 4144** [virtual tables] might change the database indirectly as a side effect. 4145** ^(For example, if an application defines a function "eval()" that 4146** calls [sqlite3_exec()], then the following SQL statement would 4147** change the database file through side-effects: 4148** 4149** <blockquote><pre> 4150** SELECT eval('DELETE FROM t1') FROM t2; 4151** </pre></blockquote> 4152** 4153** But because the [SELECT] statement does not change the database file 4154** directly, sqlite3_stmt_readonly() would still return true.)^ 4155** 4156** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 4157** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 4158** since the statements themselves do not actually modify the database but 4159** rather they control the timing of when other statements modify the 4160** database. ^The [ATTACH] and [DETACH] statements also cause 4161** sqlite3_stmt_readonly() to return true since, while those statements 4162** change the configuration of a database connection, they do not make 4163** changes to the content of the database files on disk. 4164** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 4165** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 4166** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 4167** sqlite3_stmt_readonly() returns false for those commands. 4168*/ 4169int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 4170 4171/* 4172** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement 4173** METHOD: sqlite3_stmt 4174** 4175** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the 4176** prepared statement S is an EXPLAIN statement, or 2 if the 4177** statement S is an EXPLAIN QUERY PLAN. 4178** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is 4179** an ordinary statement or a NULL pointer. 4180*/ 4181int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt); 4182 4183/* 4184** CAPI3REF: Determine If A Prepared Statement Has Been Reset 4185** METHOD: sqlite3_stmt 4186** 4187** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 4188** [prepared statement] S has been stepped at least once using 4189** [sqlite3_step(S)] but has neither run to completion (returned 4190** [SQLITE_DONE] from [sqlite3_step(S)]) nor 4191** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 4192** interface returns false if S is a NULL pointer. If S is not a 4193** NULL pointer and is not a pointer to a valid [prepared statement] 4194** object, then the behavior is undefined and probably undesirable. 4195** 4196** This interface can be used in combination [sqlite3_next_stmt()] 4197** to locate all prepared statements associated with a database 4198** connection that are in need of being reset. This can be used, 4199** for example, in diagnostic routines to search for prepared 4200** statements that are holding a transaction open. 4201*/ 4202int sqlite3_stmt_busy(sqlite3_stmt*); 4203 4204/* 4205** CAPI3REF: Dynamically Typed Value Object 4206** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 4207** 4208** SQLite uses the sqlite3_value object to represent all values 4209** that can be stored in a database table. SQLite uses dynamic typing 4210** for the values it stores. ^Values stored in sqlite3_value objects 4211** can be integers, floating point values, strings, BLOBs, or NULL. 4212** 4213** An sqlite3_value object may be either "protected" or "unprotected". 4214** Some interfaces require a protected sqlite3_value. Other interfaces 4215** will accept either a protected or an unprotected sqlite3_value. 4216** Every interface that accepts sqlite3_value arguments specifies 4217** whether or not it requires a protected sqlite3_value. The 4218** [sqlite3_value_dup()] interface can be used to construct a new 4219** protected sqlite3_value from an unprotected sqlite3_value. 4220** 4221** The terms "protected" and "unprotected" refer to whether or not 4222** a mutex is held. An internal mutex is held for a protected 4223** sqlite3_value object but no mutex is held for an unprotected 4224** sqlite3_value object. If SQLite is compiled to be single-threaded 4225** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 4226** or if SQLite is run in one of reduced mutex modes 4227** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 4228** then there is no distinction between protected and unprotected 4229** sqlite3_value objects and they can be used interchangeably. However, 4230** for maximum code portability it is recommended that applications 4231** still make the distinction between protected and unprotected 4232** sqlite3_value objects even when not strictly required. 4233** 4234** ^The sqlite3_value objects that are passed as parameters into the 4235** implementation of [application-defined SQL functions] are protected. 4236** ^The sqlite3_value object returned by 4237** [sqlite3_column_value()] is unprotected. 4238** Unprotected sqlite3_value objects may only be used as arguments 4239** to [sqlite3_result_value()], [sqlite3_bind_value()], and 4240** [sqlite3_value_dup()]. 4241** The [sqlite3_value_blob | sqlite3_value_type()] family of 4242** interfaces require protected sqlite3_value objects. 4243*/ 4244typedef struct sqlite3_value sqlite3_value; 4245 4246/* 4247** CAPI3REF: SQL Function Context Object 4248** 4249** The context in which an SQL function executes is stored in an 4250** sqlite3_context object. ^A pointer to an sqlite3_context object 4251** is always first parameter to [application-defined SQL functions]. 4252** The application-defined SQL function implementation will pass this 4253** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 4254** [sqlite3_aggregate_context()], [sqlite3_user_data()], 4255** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 4256** and/or [sqlite3_set_auxdata()]. 4257*/ 4258typedef struct sqlite3_context sqlite3_context; 4259 4260/* 4261** CAPI3REF: Binding Values To Prepared Statements 4262** KEYWORDS: {host parameter} {host parameters} {host parameter name} 4263** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 4264** METHOD: sqlite3_stmt 4265** 4266** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 4267** literals may be replaced by a [parameter] that matches one of following 4268** templates: 4269** 4270** <ul> 4271** <li> ? 4272** <li> ?NNN 4273** <li> :VVV 4274** <li> @VVV 4275** <li> $VVV 4276** </ul> 4277** 4278** In the templates above, NNN represents an integer literal, 4279** and VVV represents an alphanumeric identifier.)^ ^The values of these 4280** parameters (also called "host parameter names" or "SQL parameters") 4281** can be set using the sqlite3_bind_*() routines defined here. 4282** 4283** ^The first argument to the sqlite3_bind_*() routines is always 4284** a pointer to the [sqlite3_stmt] object returned from 4285** [sqlite3_prepare_v2()] or its variants. 4286** 4287** ^The second argument is the index of the SQL parameter to be set. 4288** ^The leftmost SQL parameter has an index of 1. ^When the same named 4289** SQL parameter is used more than once, second and subsequent 4290** occurrences have the same index as the first occurrence. 4291** ^The index for named parameters can be looked up using the 4292** [sqlite3_bind_parameter_index()] API if desired. ^The index 4293** for "?NNN" parameters is the value of NNN. 4294** ^The NNN value must be between 1 and the [sqlite3_limit()] 4295** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766). 4296** 4297** ^The third argument is the value to bind to the parameter. 4298** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4299** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 4300** is ignored and the end result is the same as sqlite3_bind_null(). 4301** ^If the third parameter to sqlite3_bind_text() is not NULL, then 4302** it should be a pointer to well-formed UTF8 text. 4303** ^If the third parameter to sqlite3_bind_text16() is not NULL, then 4304** it should be a pointer to well-formed UTF16 text. 4305** ^If the third parameter to sqlite3_bind_text64() is not NULL, then 4306** it should be a pointer to a well-formed unicode string that is 4307** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16 4308** otherwise. 4309** 4310** [[byte-order determination rules]] ^The byte-order of 4311** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF) 4312** found in first character, which is removed, or in the absence of a BOM 4313** the byte order is the native byte order of the host 4314** machine for sqlite3_bind_text16() or the byte order specified in 4315** the 6th parameter for sqlite3_bind_text64().)^ 4316** ^If UTF16 input text contains invalid unicode 4317** characters, then SQLite might change those invalid characters 4318** into the unicode replacement character: U+FFFD. 4319** 4320** ^(In those routines that have a fourth argument, its value is the 4321** number of bytes in the parameter. To be clear: the value is the 4322** number of <u>bytes</u> in the value, not the number of characters.)^ 4323** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4324** is negative, then the length of the string is 4325** the number of bytes up to the first zero terminator. 4326** If the fourth parameter to sqlite3_bind_blob() is negative, then 4327** the behavior is undefined. 4328** If a non-negative fourth parameter is provided to sqlite3_bind_text() 4329** or sqlite3_bind_text16() or sqlite3_bind_text64() then 4330** that parameter must be the byte offset 4331** where the NUL terminator would occur assuming the string were NUL 4332** terminated. If any NUL characters occurs at byte offsets less than 4333** the value of the fourth parameter then the resulting string value will 4334** contain embedded NULs. The result of expressions involving strings 4335** with embedded NULs is undefined. 4336** 4337** ^The fifth argument to the BLOB and string binding interfaces 4338** is a destructor used to dispose of the BLOB or 4339** string after SQLite has finished with it. ^The destructor is called 4340** to dispose of the BLOB or string even if the call to the bind API fails, 4341** except the destructor is not called if the third parameter is a NULL 4342** pointer or the fourth parameter is negative. 4343** ^If the fifth argument is 4344** the special value [SQLITE_STATIC], then SQLite assumes that the 4345** information is in static, unmanaged space and does not need to be freed. 4346** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 4347** SQLite makes its own private copy of the data immediately, before 4348** the sqlite3_bind_*() routine returns. 4349** 4350** ^The sixth argument to sqlite3_bind_text64() must be one of 4351** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 4352** to specify the encoding of the text in the third parameter. If 4353** the sixth argument to sqlite3_bind_text64() is not one of the 4354** allowed values shown above, or if the text encoding is different 4355** from the encoding specified by the sixth parameter, then the behavior 4356** is undefined. 4357** 4358** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 4359** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 4360** (just an integer to hold its size) while it is being processed. 4361** Zeroblobs are intended to serve as placeholders for BLOBs whose 4362** content is later written using 4363** [sqlite3_blob_open | incremental BLOB I/O] routines. 4364** ^A negative value for the zeroblob results in a zero-length BLOB. 4365** 4366** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 4367** [prepared statement] S to have an SQL value of NULL, but to also be 4368** associated with the pointer P of type T. ^D is either a NULL pointer or 4369** a pointer to a destructor function for P. ^SQLite will invoke the 4370** destructor D with a single argument of P when it is finished using 4371** P. The T parameter should be a static string, preferably a string 4372** literal. The sqlite3_bind_pointer() routine is part of the 4373** [pointer passing interface] added for SQLite 3.20.0. 4374** 4375** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 4376** for the [prepared statement] or with a prepared statement for which 4377** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 4378** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 4379** routine is passed a [prepared statement] that has been finalized, the 4380** result is undefined and probably harmful. 4381** 4382** ^Bindings are not cleared by the [sqlite3_reset()] routine. 4383** ^Unbound parameters are interpreted as NULL. 4384** 4385** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 4386** [error code] if anything goes wrong. 4387** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 4388** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 4389** [SQLITE_MAX_LENGTH]. 4390** ^[SQLITE_RANGE] is returned if the parameter 4391** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 4392** 4393** See also: [sqlite3_bind_parameter_count()], 4394** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 4395*/ 4396int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 4397int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 4398 void(*)(void*)); 4399int sqlite3_bind_double(sqlite3_stmt*, int, double); 4400int sqlite3_bind_int(sqlite3_stmt*, int, int); 4401int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 4402int sqlite3_bind_null(sqlite3_stmt*, int); 4403int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 4404int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 4405int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 4406 void(*)(void*), unsigned char encoding); 4407int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 4408int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 4409int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 4410int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 4411 4412/* 4413** CAPI3REF: Number Of SQL Parameters 4414** METHOD: sqlite3_stmt 4415** 4416** ^This routine can be used to find the number of [SQL parameters] 4417** in a [prepared statement]. SQL parameters are tokens of the 4418** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4419** placeholders for values that are [sqlite3_bind_blob | bound] 4420** to the parameters at a later time. 4421** 4422** ^(This routine actually returns the index of the largest (rightmost) 4423** parameter. For all forms except ?NNN, this will correspond to the 4424** number of unique parameters. If parameters of the ?NNN form are used, 4425** there may be gaps in the list.)^ 4426** 4427** See also: [sqlite3_bind_blob|sqlite3_bind()], 4428** [sqlite3_bind_parameter_name()], and 4429** [sqlite3_bind_parameter_index()]. 4430*/ 4431int sqlite3_bind_parameter_count(sqlite3_stmt*); 4432 4433/* 4434** CAPI3REF: Name Of A Host Parameter 4435** METHOD: sqlite3_stmt 4436** 4437** ^The sqlite3_bind_parameter_name(P,N) interface returns 4438** the name of the N-th [SQL parameter] in the [prepared statement] P. 4439** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4440** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4441** respectively. 4442** In other words, the initial ":" or "$" or "@" or "?" 4443** is included as part of the name.)^ 4444** ^Parameters of the form "?" without a following integer have no name 4445** and are referred to as "nameless" or "anonymous parameters". 4446** 4447** ^The first host parameter has an index of 1, not 0. 4448** 4449** ^If the value N is out of range or if the N-th parameter is 4450** nameless, then NULL is returned. ^The returned string is 4451** always in UTF-8 encoding even if the named parameter was 4452** originally specified as UTF-16 in [sqlite3_prepare16()], 4453** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4454** 4455** See also: [sqlite3_bind_blob|sqlite3_bind()], 4456** [sqlite3_bind_parameter_count()], and 4457** [sqlite3_bind_parameter_index()]. 4458*/ 4459const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4460 4461/* 4462** CAPI3REF: Index Of A Parameter With A Given Name 4463** METHOD: sqlite3_stmt 4464** 4465** ^Return the index of an SQL parameter given its name. ^The 4466** index value returned is suitable for use as the second 4467** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4468** is returned if no matching parameter is found. ^The parameter 4469** name must be given in UTF-8 even if the original statement 4470** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4471** [sqlite3_prepare16_v3()]. 4472** 4473** See also: [sqlite3_bind_blob|sqlite3_bind()], 4474** [sqlite3_bind_parameter_count()], and 4475** [sqlite3_bind_parameter_name()]. 4476*/ 4477int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4478 4479/* 4480** CAPI3REF: Reset All Bindings On A Prepared Statement 4481** METHOD: sqlite3_stmt 4482** 4483** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4484** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4485** ^Use this routine to reset all host parameters to NULL. 4486*/ 4487int sqlite3_clear_bindings(sqlite3_stmt*); 4488 4489/* 4490** CAPI3REF: Number Of Columns In A Result Set 4491** METHOD: sqlite3_stmt 4492** 4493** ^Return the number of columns in the result set returned by the 4494** [prepared statement]. ^If this routine returns 0, that means the 4495** [prepared statement] returns no data (for example an [UPDATE]). 4496** ^However, just because this routine returns a positive number does not 4497** mean that one or more rows of data will be returned. ^A SELECT statement 4498** will always have a positive sqlite3_column_count() but depending on the 4499** WHERE clause constraints and the table content, it might return no rows. 4500** 4501** See also: [sqlite3_data_count()] 4502*/ 4503int sqlite3_column_count(sqlite3_stmt *pStmt); 4504 4505/* 4506** CAPI3REF: Column Names In A Result Set 4507** METHOD: sqlite3_stmt 4508** 4509** ^These routines return the name assigned to a particular column 4510** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4511** interface returns a pointer to a zero-terminated UTF-8 string 4512** and sqlite3_column_name16() returns a pointer to a zero-terminated 4513** UTF-16 string. ^The first parameter is the [prepared statement] 4514** that implements the [SELECT] statement. ^The second parameter is the 4515** column number. ^The leftmost column is number 0. 4516** 4517** ^The returned string pointer is valid until either the [prepared statement] 4518** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4519** reprepared by the first call to [sqlite3_step()] for a particular run 4520** or until the next call to 4521** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4522** 4523** ^If sqlite3_malloc() fails during the processing of either routine 4524** (for example during a conversion from UTF-8 to UTF-16) then a 4525** NULL pointer is returned. 4526** 4527** ^The name of a result column is the value of the "AS" clause for 4528** that column, if there is an AS clause. If there is no AS clause 4529** then the name of the column is unspecified and may change from 4530** one release of SQLite to the next. 4531*/ 4532const char *sqlite3_column_name(sqlite3_stmt*, int N); 4533const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4534 4535/* 4536** CAPI3REF: Source Of Data In A Query Result 4537** METHOD: sqlite3_stmt 4538** 4539** ^These routines provide a means to determine the database, table, and 4540** table column that is the origin of a particular result column in 4541** [SELECT] statement. 4542** ^The name of the database or table or column can be returned as 4543** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4544** the database name, the _table_ routines return the table name, and 4545** the origin_ routines return the column name. 4546** ^The returned string is valid until the [prepared statement] is destroyed 4547** using [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 same information is requested 4550** again in a different encoding. 4551** 4552** ^The names returned are the original un-aliased names of the 4553** database, table, and column. 4554** 4555** ^The first argument to these interfaces is a [prepared statement]. 4556** ^These functions return information about the Nth result column returned by 4557** the statement, where N is the second function argument. 4558** ^The left-most column is column 0 for these routines. 4559** 4560** ^If the Nth column returned by the statement is an expression or 4561** subquery and is not a column value, then all of these functions return 4562** NULL. ^These routines might also return NULL if a memory allocation error 4563** occurs. ^Otherwise, they return the name of the attached database, table, 4564** or column that query result column was extracted from. 4565** 4566** ^As with all other SQLite APIs, those whose names end with "16" return 4567** UTF-16 encoded strings and the other functions return UTF-8. 4568** 4569** ^These APIs are only available if the library was compiled with the 4570** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4571** 4572** If two or more threads call one or more 4573** [sqlite3_column_database_name | column metadata interfaces] 4574** for the same [prepared statement] and result column 4575** at the same time then the results are undefined. 4576*/ 4577const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4578const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4579const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4580const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4581const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4582const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4583 4584/* 4585** CAPI3REF: Declared Datatype Of A Query Result 4586** METHOD: sqlite3_stmt 4587** 4588** ^(The first parameter is a [prepared statement]. 4589** If this statement is a [SELECT] statement and the Nth column of the 4590** returned result set of that [SELECT] is a table column (not an 4591** expression or subquery) then the declared type of the table 4592** column is returned.)^ ^If the Nth column of the result set is an 4593** expression or subquery, then a NULL pointer is returned. 4594** ^The returned string is always UTF-8 encoded. 4595** 4596** ^(For example, given the database schema: 4597** 4598** CREATE TABLE t1(c1 VARIANT); 4599** 4600** and the following statement to be compiled: 4601** 4602** SELECT c1 + 1, c1 FROM t1; 4603** 4604** this routine would return the string "VARIANT" for the second result 4605** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4606** 4607** ^SQLite uses dynamic run-time typing. ^So just because a column 4608** is declared to contain a particular type does not mean that the 4609** data stored in that column is of the declared type. SQLite is 4610** strongly typed, but the typing is dynamic not static. ^Type 4611** is associated with individual values, not with the containers 4612** used to hold those values. 4613*/ 4614const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4615const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4616 4617/* 4618** CAPI3REF: Evaluate An SQL Statement 4619** METHOD: sqlite3_stmt 4620** 4621** After a [prepared statement] has been prepared using any of 4622** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4623** or [sqlite3_prepare16_v3()] or one of the legacy 4624** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4625** must be called one or more times to evaluate the statement. 4626** 4627** The details of the behavior of the sqlite3_step() interface depend 4628** on whether the statement was prepared using the newer "vX" interfaces 4629** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4630** [sqlite3_prepare16_v2()] or the older legacy 4631** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4632** new "vX" interface is recommended for new applications but the legacy 4633** interface will continue to be supported. 4634** 4635** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4636** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4637** ^With the "v2" interface, any of the other [result codes] or 4638** [extended result codes] might be returned as well. 4639** 4640** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4641** database locks it needs to do its job. ^If the statement is a [COMMIT] 4642** or occurs outside of an explicit transaction, then you can retry the 4643** statement. If the statement is not a [COMMIT] and occurs within an 4644** explicit transaction then you should rollback the transaction before 4645** continuing. 4646** 4647** ^[SQLITE_DONE] means that the statement has finished executing 4648** successfully. sqlite3_step() should not be called again on this virtual 4649** machine without first calling [sqlite3_reset()] to reset the virtual 4650** machine back to its initial state. 4651** 4652** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4653** is returned each time a new row of data is ready for processing by the 4654** caller. The values may be accessed using the [column access functions]. 4655** sqlite3_step() is called again to retrieve the next row of data. 4656** 4657** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4658** violation) has occurred. sqlite3_step() should not be called again on 4659** the VM. More information may be found by calling [sqlite3_errmsg()]. 4660** ^With the legacy interface, a more specific error code (for example, 4661** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4662** can be obtained by calling [sqlite3_reset()] on the 4663** [prepared statement]. ^In the "v2" interface, 4664** the more specific error code is returned directly by sqlite3_step(). 4665** 4666** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4667** Perhaps it was called on a [prepared statement] that has 4668** already been [sqlite3_finalize | finalized] or on one that had 4669** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4670** be the case that the same database connection is being used by two or 4671** more threads at the same moment in time. 4672** 4673** For all versions of SQLite up to and including 3.6.23.1, a call to 4674** [sqlite3_reset()] was required after sqlite3_step() returned anything 4675** other than [SQLITE_ROW] before any subsequent invocation of 4676** sqlite3_step(). Failure to reset the prepared statement using 4677** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4678** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4679** sqlite3_step() began 4680** calling [sqlite3_reset()] automatically in this circumstance rather 4681** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4682** break because any application that ever receives an SQLITE_MISUSE error 4683** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4684** can be used to restore the legacy behavior. 4685** 4686** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4687** API always returns a generic error code, [SQLITE_ERROR], following any 4688** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4689** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4690** specific [error codes] that better describes the error. 4691** We admit that this is a goofy design. The problem has been fixed 4692** with the "v2" interface. If you prepare all of your SQL statements 4693** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4694** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4695** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4696** then the more specific [error codes] are returned directly 4697** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4698*/ 4699int sqlite3_step(sqlite3_stmt*); 4700 4701/* 4702** CAPI3REF: Number of columns in a result set 4703** METHOD: sqlite3_stmt 4704** 4705** ^The sqlite3_data_count(P) interface returns the number of columns in the 4706** current row of the result set of [prepared statement] P. 4707** ^If prepared statement P does not have results ready to return 4708** (via calls to the [sqlite3_column_int | sqlite3_column()] family of 4709** interfaces) then sqlite3_data_count(P) returns 0. 4710** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4711** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4712** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4713** will return non-zero if previous call to [sqlite3_step](P) returned 4714** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4715** where it always returns zero since each step of that multi-step 4716** pragma returns 0 columns of data. 4717** 4718** See also: [sqlite3_column_count()] 4719*/ 4720int sqlite3_data_count(sqlite3_stmt *pStmt); 4721 4722/* 4723** CAPI3REF: Fundamental Datatypes 4724** KEYWORDS: SQLITE_TEXT 4725** 4726** ^(Every value in SQLite has one of five fundamental datatypes: 4727** 4728** <ul> 4729** <li> 64-bit signed integer 4730** <li> 64-bit IEEE floating point number 4731** <li> string 4732** <li> BLOB 4733** <li> NULL 4734** </ul>)^ 4735** 4736** These constants are codes for each of those types. 4737** 4738** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4739** for a completely different meaning. Software that links against both 4740** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4741** SQLITE_TEXT. 4742*/ 4743#define SQLITE_INTEGER 1 4744#define SQLITE_FLOAT 2 4745#define SQLITE_BLOB 4 4746#define SQLITE_NULL 5 4747#ifdef SQLITE_TEXT 4748# undef SQLITE_TEXT 4749#else 4750# define SQLITE_TEXT 3 4751#endif 4752#define SQLITE3_TEXT 3 4753 4754/* 4755** CAPI3REF: Result Values From A Query 4756** KEYWORDS: {column access functions} 4757** METHOD: sqlite3_stmt 4758** 4759** <b>Summary:</b> 4760** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4761** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4762** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4763** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4764** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4765** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4766** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4767** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4768** [sqlite3_value|unprotected sqlite3_value] object. 4769** <tr><td> <td> <td> 4770** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4771** or a UTF-8 TEXT result in bytes 4772** <tr><td><b>sqlite3_column_bytes16 </b> 4773** <td>→ <td>Size of UTF-16 4774** TEXT in bytes 4775** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4776** datatype of the result 4777** </table></blockquote> 4778** 4779** <b>Details:</b> 4780** 4781** ^These routines return information about a single column of the current 4782** result row of a query. ^In every case the first argument is a pointer 4783** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4784** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4785** and the second argument is the index of the column for which information 4786** should be returned. ^The leftmost column of the result set has the index 0. 4787** ^The number of columns in the result can be determined using 4788** [sqlite3_column_count()]. 4789** 4790** If the SQL statement does not currently point to a valid row, or if the 4791** column index is out of range, the result is undefined. 4792** These routines may only be called when the most recent call to 4793** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4794** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4795** If any of these routines are called after [sqlite3_reset()] or 4796** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4797** something other than [SQLITE_ROW], the results are undefined. 4798** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4799** are called from a different thread while any of these routines 4800** are pending, then the results are undefined. 4801** 4802** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4803** each return the value of a result column in a specific data format. If 4804** the result column is not initially in the requested format (for example, 4805** if the query returns an integer but the sqlite3_column_text() interface 4806** is used to extract the value) then an automatic type conversion is performed. 4807** 4808** ^The sqlite3_column_type() routine returns the 4809** [SQLITE_INTEGER | datatype code] for the initial data type 4810** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4811** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4812** The return value of sqlite3_column_type() can be used to decide which 4813** of the first six interface should be used to extract the column value. 4814** The value returned by sqlite3_column_type() is only meaningful if no 4815** automatic type conversions have occurred for the value in question. 4816** After a type conversion, the result of calling sqlite3_column_type() 4817** is undefined, though harmless. Future 4818** versions of SQLite may change the behavior of sqlite3_column_type() 4819** following a type conversion. 4820** 4821** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4822** or sqlite3_column_bytes16() interfaces can be used to determine the size 4823** of that BLOB or string. 4824** 4825** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4826** routine returns the number of bytes in that BLOB or string. 4827** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4828** the string to UTF-8 and then returns the number of bytes. 4829** ^If the result is a numeric value then sqlite3_column_bytes() uses 4830** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4831** the number of bytes in that string. 4832** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4833** 4834** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4835** routine returns the number of bytes in that BLOB or string. 4836** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4837** the string to UTF-16 and then returns the number of bytes. 4838** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4839** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4840** the number of bytes in that string. 4841** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4842** 4843** ^The values returned by [sqlite3_column_bytes()] and 4844** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4845** of the string. ^For clarity: the values returned by 4846** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4847** bytes in the string, not the number of characters. 4848** 4849** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4850** even empty strings, are always zero-terminated. ^The return 4851** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4852** 4853** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4854** [unprotected sqlite3_value] object. In a multithreaded environment, 4855** an unprotected sqlite3_value object may only be used safely with 4856** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4857** If the [unprotected sqlite3_value] object returned by 4858** [sqlite3_column_value()] is used in any other way, including calls 4859** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4860** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4861** Hence, the sqlite3_column_value() interface 4862** is normally only useful within the implementation of 4863** [application-defined SQL functions] or [virtual tables], not within 4864** top-level application code. 4865** 4866** The these routines may attempt to convert the datatype of the result. 4867** ^For example, if the internal representation is FLOAT and a text result 4868** is requested, [sqlite3_snprintf()] is used internally to perform the 4869** conversion automatically. ^(The following table details the conversions 4870** that are applied: 4871** 4872** <blockquote> 4873** <table border="1"> 4874** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4875** 4876** <tr><td> NULL <td> INTEGER <td> Result is 0 4877** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4878** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4879** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4880** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4881** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4882** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4883** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4884** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4885** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4886** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4887** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4888** <tr><td> TEXT <td> BLOB <td> No change 4889** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4890** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4891** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4892** </table> 4893** </blockquote>)^ 4894** 4895** Note that when type conversions occur, pointers returned by prior 4896** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4897** sqlite3_column_text16() may be invalidated. 4898** Type conversions and pointer invalidations might occur 4899** in the following cases: 4900** 4901** <ul> 4902** <li> The initial content is a BLOB and sqlite3_column_text() or 4903** sqlite3_column_text16() is called. A zero-terminator might 4904** need to be added to the string.</li> 4905** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4906** sqlite3_column_text16() is called. The content must be converted 4907** to UTF-16.</li> 4908** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4909** sqlite3_column_text() is called. The content must be converted 4910** to UTF-8.</li> 4911** </ul> 4912** 4913** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4914** not invalidate a prior pointer, though of course the content of the buffer 4915** that the prior pointer references will have been modified. Other kinds 4916** of conversion are done in place when it is possible, but sometimes they 4917** are not possible and in those cases prior pointers are invalidated. 4918** 4919** The safest policy is to invoke these routines 4920** in one of the following ways: 4921** 4922** <ul> 4923** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4924** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4925** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4926** </ul> 4927** 4928** In other words, you should call sqlite3_column_text(), 4929** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4930** into the desired format, then invoke sqlite3_column_bytes() or 4931** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4932** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4933** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4934** with calls to sqlite3_column_bytes(). 4935** 4936** ^The pointers returned are valid until a type conversion occurs as 4937** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4938** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4939** and BLOBs is freed automatically. Do not pass the pointers returned 4940** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4941** [sqlite3_free()]. 4942** 4943** As long as the input parameters are correct, these routines will only 4944** fail if an out-of-memory error occurs during a format conversion. 4945** Only the following subset of interfaces are subject to out-of-memory 4946** errors: 4947** 4948** <ul> 4949** <li> sqlite3_column_blob() 4950** <li> sqlite3_column_text() 4951** <li> sqlite3_column_text16() 4952** <li> sqlite3_column_bytes() 4953** <li> sqlite3_column_bytes16() 4954** </ul> 4955** 4956** If an out-of-memory error occurs, then the return value from these 4957** routines is the same as if the column had contained an SQL NULL value. 4958** Valid SQL NULL returns can be distinguished from out-of-memory errors 4959** by invoking the [sqlite3_errcode()] immediately after the suspect 4960** return value is obtained and before any 4961** other SQLite interface is called on the same [database connection]. 4962*/ 4963const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4964double sqlite3_column_double(sqlite3_stmt*, int iCol); 4965int sqlite3_column_int(sqlite3_stmt*, int iCol); 4966sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4967const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4968const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4969sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4970int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4971int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4972int sqlite3_column_type(sqlite3_stmt*, int iCol); 4973 4974/* 4975** CAPI3REF: Destroy A Prepared Statement Object 4976** DESTRUCTOR: sqlite3_stmt 4977** 4978** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4979** ^If the most recent evaluation of the statement encountered no errors 4980** or if the statement is never been evaluated, then sqlite3_finalize() returns 4981** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4982** sqlite3_finalize(S) returns the appropriate [error code] or 4983** [extended error code]. 4984** 4985** ^The sqlite3_finalize(S) routine can be called at any point during 4986** the life cycle of [prepared statement] S: 4987** before statement S is ever evaluated, after 4988** one or more calls to [sqlite3_reset()], or after any call 4989** to [sqlite3_step()] regardless of whether or not the statement has 4990** completed execution. 4991** 4992** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4993** 4994** The application must finalize every [prepared statement] in order to avoid 4995** resource leaks. It is a grievous error for the application to try to use 4996** a prepared statement after it has been finalized. Any use of a prepared 4997** statement after it has been finalized can result in undefined and 4998** undesirable behavior such as segfaults and heap corruption. 4999*/ 5000int sqlite3_finalize(sqlite3_stmt *pStmt); 5001 5002/* 5003** CAPI3REF: Reset A Prepared Statement Object 5004** METHOD: sqlite3_stmt 5005** 5006** The sqlite3_reset() function is called to reset a [prepared statement] 5007** object back to its initial state, ready to be re-executed. 5008** ^Any SQL statement variables that had values bound to them using 5009** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 5010** Use [sqlite3_clear_bindings()] to reset the bindings. 5011** 5012** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 5013** back to the beginning of its program. 5014** 5015** ^If the most recent call to [sqlite3_step(S)] for the 5016** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 5017** or if [sqlite3_step(S)] has never before been called on S, 5018** then [sqlite3_reset(S)] returns [SQLITE_OK]. 5019** 5020** ^If the most recent call to [sqlite3_step(S)] for the 5021** [prepared statement] S indicated an error, then 5022** [sqlite3_reset(S)] returns an appropriate [error code]. 5023** 5024** ^The [sqlite3_reset(S)] interface does not change the values 5025** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 5026*/ 5027int sqlite3_reset(sqlite3_stmt *pStmt); 5028 5029/* 5030** CAPI3REF: Create Or Redefine SQL Functions 5031** KEYWORDS: {function creation routines} 5032** METHOD: sqlite3 5033** 5034** ^These functions (collectively known as "function creation routines") 5035** are used to add SQL functions or aggregates or to redefine the behavior 5036** of existing SQL functions or aggregates. The only differences between 5037** the three "sqlite3_create_function*" routines are the text encoding 5038** expected for the second parameter (the name of the function being 5039** created) and the presence or absence of a destructor callback for 5040** the application data pointer. Function sqlite3_create_window_function() 5041** is similar, but allows the user to supply the extra callback functions 5042** needed by [aggregate window functions]. 5043** 5044** ^The first parameter is the [database connection] to which the SQL 5045** function is to be added. ^If an application uses more than one database 5046** connection then application-defined SQL functions must be added 5047** to each database connection separately. 5048** 5049** ^The second parameter is the name of the SQL function to be created or 5050** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 5051** representation, exclusive of the zero-terminator. ^Note that the name 5052** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 5053** ^Any attempt to create a function with a longer name 5054** will result in [SQLITE_MISUSE] being returned. 5055** 5056** ^The third parameter (nArg) 5057** is the number of arguments that the SQL function or 5058** aggregate takes. ^If this parameter is -1, then the SQL function or 5059** aggregate may take any number of arguments between 0 and the limit 5060** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 5061** parameter is less than -1 or greater than 127 then the behavior is 5062** undefined. 5063** 5064** ^The fourth parameter, eTextRep, specifies what 5065** [SQLITE_UTF8 | text encoding] this SQL function prefers for 5066** its parameters. The application should set this parameter to 5067** [SQLITE_UTF16LE] if the function implementation invokes 5068** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 5069** implementation invokes [sqlite3_value_text16be()] on an input, or 5070** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 5071** otherwise. ^The same SQL function may be registered multiple times using 5072** different preferred text encodings, with different implementations for 5073** each encoding. 5074** ^When multiple implementations of the same function are available, SQLite 5075** will pick the one that involves the least amount of data conversion. 5076** 5077** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 5078** to signal that the function will always return the same result given 5079** the same inputs within a single SQL statement. Most SQL functions are 5080** deterministic. The built-in [random()] SQL function is an example of a 5081** function that is not deterministic. The SQLite query planner is able to 5082** perform additional optimizations on deterministic functions, so use 5083** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 5084** 5085** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY] 5086** flag, which if present prevents the function from being invoked from 5087** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions, 5088** index expressions, or the WHERE clause of partial indexes. 5089** 5090** <span style="background-color:#ffff90;"> 5091** For best security, the [SQLITE_DIRECTONLY] flag is recommended for 5092** all application-defined SQL functions that do not need to be 5093** used inside of triggers, view, CHECK constraints, or other elements of 5094** the database schema. This flags is especially recommended for SQL 5095** functions that have side effects or reveal internal application state. 5096** Without this flag, an attacker might be able to modify the schema of 5097** a database file to include invocations of the function with parameters 5098** chosen by the attacker, which the application will then execute when 5099** the database file is opened and read. 5100** </span> 5101** 5102** ^(The fifth parameter is an arbitrary pointer. The implementation of the 5103** function can gain access to this pointer using [sqlite3_user_data()].)^ 5104** 5105** ^The sixth, seventh and eighth parameters passed to the three 5106** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are 5107** pointers to C-language functions that implement the SQL function or 5108** aggregate. ^A scalar SQL function requires an implementation of the xFunc 5109** callback only; NULL pointers must be passed as the xStep and xFinal 5110** parameters. ^An aggregate SQL function requires an implementation of xStep 5111** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 5112** SQL function or aggregate, pass NULL pointers for all three function 5113** callbacks. 5114** 5115** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue 5116** and xInverse) passed to sqlite3_create_window_function are pointers to 5117** C-language callbacks that implement the new function. xStep and xFinal 5118** must both be non-NULL. xValue and xInverse may either both be NULL, in 5119** which case a regular aggregate function is created, or must both be 5120** non-NULL, in which case the new function may be used as either an aggregate 5121** or aggregate window function. More details regarding the implementation 5122** of aggregate window functions are 5123** [user-defined window functions|available here]. 5124** 5125** ^(If the final parameter to sqlite3_create_function_v2() or 5126** sqlite3_create_window_function() is not NULL, then it is destructor for 5127** the application data pointer. The destructor is invoked when the function 5128** is deleted, either by being overloaded or when the database connection 5129** closes.)^ ^The destructor is also invoked if the call to 5130** sqlite3_create_function_v2() fails. ^When the destructor callback is 5131** invoked, it is passed a single argument which is a copy of the application 5132** data pointer which was the fifth parameter to sqlite3_create_function_v2(). 5133** 5134** ^It is permitted to register multiple implementations of the same 5135** functions with the same name but with either differing numbers of 5136** arguments or differing preferred text encodings. ^SQLite will use 5137** the implementation that most closely matches the way in which the 5138** SQL function is used. ^A function implementation with a non-negative 5139** nArg parameter is a better match than a function implementation with 5140** a negative nArg. ^A function where the preferred text encoding 5141** matches the database encoding is a better 5142** match than a function where the encoding is different. 5143** ^A function where the encoding difference is between UTF16le and UTF16be 5144** is a closer match than a function where the encoding difference is 5145** between UTF8 and UTF16. 5146** 5147** ^Built-in functions may be overloaded by new application-defined functions. 5148** 5149** ^An application-defined function is permitted to call other 5150** SQLite interfaces. However, such calls must not 5151** close the database connection nor finalize or reset the prepared 5152** statement in which the function is running. 5153*/ 5154int sqlite3_create_function( 5155 sqlite3 *db, 5156 const char *zFunctionName, 5157 int nArg, 5158 int eTextRep, 5159 void *pApp, 5160 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5161 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5162 void (*xFinal)(sqlite3_context*) 5163); 5164int sqlite3_create_function16( 5165 sqlite3 *db, 5166 const void *zFunctionName, 5167 int nArg, 5168 int eTextRep, 5169 void *pApp, 5170 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5171 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5172 void (*xFinal)(sqlite3_context*) 5173); 5174int sqlite3_create_function_v2( 5175 sqlite3 *db, 5176 const char *zFunctionName, 5177 int nArg, 5178 int eTextRep, 5179 void *pApp, 5180 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5181 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5182 void (*xFinal)(sqlite3_context*), 5183 void(*xDestroy)(void*) 5184); 5185int sqlite3_create_window_function( 5186 sqlite3 *db, 5187 const char *zFunctionName, 5188 int nArg, 5189 int eTextRep, 5190 void *pApp, 5191 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5192 void (*xFinal)(sqlite3_context*), 5193 void (*xValue)(sqlite3_context*), 5194 void (*xInverse)(sqlite3_context*,int,sqlite3_value**), 5195 void(*xDestroy)(void*) 5196); 5197 5198/* 5199** CAPI3REF: Text Encodings 5200** 5201** These constant define integer codes that represent the various 5202** text encodings supported by SQLite. 5203*/ 5204#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 5205#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 5206#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 5207#define SQLITE_UTF16 4 /* Use native byte order */ 5208#define SQLITE_ANY 5 /* Deprecated */ 5209#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 5210 5211/* 5212** CAPI3REF: Function Flags 5213** 5214** These constants may be ORed together with the 5215** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 5216** to [sqlite3_create_function()], [sqlite3_create_function16()], or 5217** [sqlite3_create_function_v2()]. 5218** 5219** <dl> 5220** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd> 5221** The SQLITE_DETERMINISTIC flag means that the new function always gives 5222** the same output when the input parameters are the same. 5223** The [abs|abs() function] is deterministic, for example, but 5224** [randomblob|randomblob()] is not. Functions must 5225** be deterministic in order to be used in certain contexts such as 5226** with the WHERE clause of [partial indexes] or in [generated columns]. 5227** SQLite might also optimize deterministic functions by factoring them 5228** out of inner loops. 5229** </dd> 5230** 5231** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd> 5232** The SQLITE_DIRECTONLY flag means that the function may only be invoked 5233** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in 5234** schema structures such as [CHECK constraints], [DEFAULT clauses], 5235** [expression indexes], [partial indexes], or [generated columns]. 5236** The SQLITE_DIRECTONLY flags is a security feature which is recommended 5237** for all [application-defined SQL functions], and especially for functions 5238** that have side-effects or that could potentially leak sensitive 5239** information. 5240** </dd> 5241** 5242** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd> 5243** The SQLITE_INNOCUOUS flag means that the function is unlikely 5244** to cause problems even if misused. An innocuous function should have 5245** no side effects and should not depend on any values other than its 5246** input parameters. The [abs|abs() function] is an example of an 5247** innocuous function. 5248** The [load_extension() SQL function] is not innocuous because of its 5249** side effects. 5250** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not 5251** exactly the same. The [random|random() function] is an example of a 5252** function that is innocuous but not deterministic. 5253** <p>Some heightened security settings 5254** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF]) 5255** disable the use of SQL functions inside views and triggers and in 5256** schema structures such as [CHECK constraints], [DEFAULT clauses], 5257** [expression indexes], [partial indexes], and [generated columns] unless 5258** the function is tagged with SQLITE_INNOCUOUS. Most built-in functions 5259** are innocuous. Developers are advised to avoid using the 5260** SQLITE_INNOCUOUS flag for application-defined functions unless the 5261** function has been carefully audited and found to be free of potentially 5262** security-adverse side-effects and information-leaks. 5263** </dd> 5264** 5265** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd> 5266** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call 5267** [sqlite3_value_subtype()] to inspect the sub-types of its arguments. 5268** Specifying this flag makes no difference for scalar or aggregate user 5269** functions. However, if it is not specified for a user-defined window 5270** function, then any sub-types belonging to arguments passed to the window 5271** function may be discarded before the window function is called (i.e. 5272** sqlite3_value_subtype() will always return 0). 5273** </dd> 5274** </dl> 5275*/ 5276#define SQLITE_DETERMINISTIC 0x000000800 5277#define SQLITE_DIRECTONLY 0x000080000 5278#define SQLITE_SUBTYPE 0x000100000 5279#define SQLITE_INNOCUOUS 0x000200000 5280 5281/* 5282** CAPI3REF: Deprecated Functions 5283** DEPRECATED 5284** 5285** These functions are [deprecated]. In order to maintain 5286** backwards compatibility with older code, these functions continue 5287** to be supported. However, new applications should avoid 5288** the use of these functions. To encourage programmers to avoid 5289** these functions, we will not explain what they do. 5290*/ 5291#ifndef SQLITE_OMIT_DEPRECATED 5292SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 5293SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 5294SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 5295SQLITE_DEPRECATED int sqlite3_global_recover(void); 5296SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 5297SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 5298 void*,sqlite3_int64); 5299#endif 5300 5301/* 5302** CAPI3REF: Obtaining SQL Values 5303** METHOD: sqlite3_value 5304** 5305** <b>Summary:</b> 5306** <blockquote><table border=0 cellpadding=0 cellspacing=0> 5307** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 5308** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 5309** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 5310** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 5311** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 5312** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 5313** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 5314** the native byteorder 5315** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 5316** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 5317** <tr><td> <td> <td> 5318** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 5319** or a UTF-8 TEXT in bytes 5320** <tr><td><b>sqlite3_value_bytes16 </b> 5321** <td>→ <td>Size of UTF-16 5322** TEXT in bytes 5323** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 5324** datatype of the value 5325** <tr><td><b>sqlite3_value_numeric_type </b> 5326** <td>→ <td>Best numeric datatype of the value 5327** <tr><td><b>sqlite3_value_nochange </b> 5328** <td>→ <td>True if the column is unchanged in an UPDATE 5329** against a virtual table. 5330** <tr><td><b>sqlite3_value_frombind </b> 5331** <td>→ <td>True if value originated from a [bound parameter] 5332** </table></blockquote> 5333** 5334** <b>Details:</b> 5335** 5336** These routines extract type, size, and content information from 5337** [protected sqlite3_value] objects. Protected sqlite3_value objects 5338** are used to pass parameter information into the functions that 5339** implement [application-defined SQL functions] and [virtual tables]. 5340** 5341** These routines work only with [protected sqlite3_value] objects. 5342** Any attempt to use these routines on an [unprotected sqlite3_value] 5343** is not threadsafe. 5344** 5345** ^These routines work just like the corresponding [column access functions] 5346** except that these routines take a single [protected sqlite3_value] object 5347** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 5348** 5349** ^The sqlite3_value_text16() interface extracts a UTF-16 string 5350** in the native byte-order of the host machine. ^The 5351** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 5352** extract UTF-16 strings as big-endian and little-endian respectively. 5353** 5354** ^If [sqlite3_value] object V was initialized 5355** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 5356** and if X and Y are strings that compare equal according to strcmp(X,Y), 5357** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 5358** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 5359** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5360** 5361** ^(The sqlite3_value_type(V) interface returns the 5362** [SQLITE_INTEGER | datatype code] for the initial datatype of the 5363** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 5364** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 5365** Other interfaces might change the datatype for an sqlite3_value object. 5366** For example, if the datatype is initially SQLITE_INTEGER and 5367** sqlite3_value_text(V) is called to extract a text value for that 5368** integer, then subsequent calls to sqlite3_value_type(V) might return 5369** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 5370** occurs is undefined and may change from one release of SQLite to the next. 5371** 5372** ^(The sqlite3_value_numeric_type() interface attempts to apply 5373** numeric affinity to the value. This means that an attempt is 5374** made to convert the value to an integer or floating point. If 5375** such a conversion is possible without loss of information (in other 5376** words, if the value is a string that looks like a number) 5377** then the conversion is performed. Otherwise no conversion occurs. 5378** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 5379** 5380** ^Within the [xUpdate] method of a [virtual table], the 5381** sqlite3_value_nochange(X) interface returns true if and only if 5382** the column corresponding to X is unchanged by the UPDATE operation 5383** that the xUpdate method call was invoked to implement and if 5384** and the prior [xColumn] method call that was invoked to extracted 5385** the value for that column returned without setting a result (probably 5386** because it queried [sqlite3_vtab_nochange()] and found that the column 5387** was unchanging). ^Within an [xUpdate] method, any value for which 5388** sqlite3_value_nochange(X) is true will in all other respects appear 5389** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 5390** than within an [xUpdate] method call for an UPDATE statement, then 5391** the return value is arbitrary and meaningless. 5392** 5393** ^The sqlite3_value_frombind(X) interface returns non-zero if the 5394** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()] 5395** interfaces. ^If X comes from an SQL literal value, or a table column, 5396** or an expression, then sqlite3_value_frombind(X) returns zero. 5397** 5398** Please pay particular attention to the fact that the pointer returned 5399** from [sqlite3_value_blob()], [sqlite3_value_text()], or 5400** [sqlite3_value_text16()] can be invalidated by a subsequent call to 5401** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 5402** or [sqlite3_value_text16()]. 5403** 5404** These routines must be called from the same thread as 5405** the SQL function that supplied the [sqlite3_value*] parameters. 5406** 5407** As long as the input parameter is correct, these routines can only 5408** fail if an out-of-memory error occurs during a format conversion. 5409** Only the following subset of interfaces are subject to out-of-memory 5410** errors: 5411** 5412** <ul> 5413** <li> sqlite3_value_blob() 5414** <li> sqlite3_value_text() 5415** <li> sqlite3_value_text16() 5416** <li> sqlite3_value_text16le() 5417** <li> sqlite3_value_text16be() 5418** <li> sqlite3_value_bytes() 5419** <li> sqlite3_value_bytes16() 5420** </ul> 5421** 5422** If an out-of-memory error occurs, then the return value from these 5423** routines is the same as if the column had contained an SQL NULL value. 5424** Valid SQL NULL returns can be distinguished from out-of-memory errors 5425** by invoking the [sqlite3_errcode()] immediately after the suspect 5426** return value is obtained and before any 5427** other SQLite interface is called on the same [database connection]. 5428*/ 5429const void *sqlite3_value_blob(sqlite3_value*); 5430double sqlite3_value_double(sqlite3_value*); 5431int sqlite3_value_int(sqlite3_value*); 5432sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 5433void *sqlite3_value_pointer(sqlite3_value*, const char*); 5434const unsigned char *sqlite3_value_text(sqlite3_value*); 5435const void *sqlite3_value_text16(sqlite3_value*); 5436const void *sqlite3_value_text16le(sqlite3_value*); 5437const void *sqlite3_value_text16be(sqlite3_value*); 5438int sqlite3_value_bytes(sqlite3_value*); 5439int sqlite3_value_bytes16(sqlite3_value*); 5440int sqlite3_value_type(sqlite3_value*); 5441int sqlite3_value_numeric_type(sqlite3_value*); 5442int sqlite3_value_nochange(sqlite3_value*); 5443int sqlite3_value_frombind(sqlite3_value*); 5444 5445/* 5446** CAPI3REF: Finding The Subtype Of SQL Values 5447** METHOD: sqlite3_value 5448** 5449** The sqlite3_value_subtype(V) function returns the subtype for 5450** an [application-defined SQL function] argument V. The subtype 5451** information can be used to pass a limited amount of context from 5452** one SQL function to another. Use the [sqlite3_result_subtype()] 5453** routine to set the subtype for the return value of an SQL function. 5454*/ 5455unsigned int sqlite3_value_subtype(sqlite3_value*); 5456 5457/* 5458** CAPI3REF: Copy And Free SQL Values 5459** METHOD: sqlite3_value 5460** 5461** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 5462** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 5463** is a [protected sqlite3_value] object even if the input is not. 5464** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 5465** memory allocation fails. 5466** 5467** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 5468** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 5469** then sqlite3_value_free(V) is a harmless no-op. 5470*/ 5471sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 5472void sqlite3_value_free(sqlite3_value*); 5473 5474/* 5475** CAPI3REF: Obtain Aggregate Function Context 5476** METHOD: sqlite3_context 5477** 5478** Implementations of aggregate SQL functions use this 5479** routine to allocate memory for storing their state. 5480** 5481** ^The first time the sqlite3_aggregate_context(C,N) routine is called 5482** for a particular aggregate function, SQLite allocates 5483** N bytes of memory, zeroes out that memory, and returns a pointer 5484** to the new memory. ^On second and subsequent calls to 5485** sqlite3_aggregate_context() for the same aggregate function instance, 5486** the same buffer is returned. Sqlite3_aggregate_context() is normally 5487** called once for each invocation of the xStep callback and then one 5488** last time when the xFinal callback is invoked. ^(When no rows match 5489** an aggregate query, the xStep() callback of the aggregate function 5490** implementation is never called and xFinal() is called exactly once. 5491** In those cases, sqlite3_aggregate_context() might be called for the 5492** first time from within xFinal().)^ 5493** 5494** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 5495** when first called if N is less than or equal to zero or if a memory 5496** allocate error occurs. 5497** 5498** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 5499** determined by the N parameter on first successful call. Changing the 5500** value of N in any subsequent call to sqlite3_aggregate_context() within 5501** the same aggregate function instance will not resize the memory 5502** allocation.)^ Within the xFinal callback, it is customary to set 5503** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 5504** pointless memory allocations occur. 5505** 5506** ^SQLite automatically frees the memory allocated by 5507** sqlite3_aggregate_context() when the aggregate query concludes. 5508** 5509** The first parameter must be a copy of the 5510** [sqlite3_context | SQL function context] that is the first parameter 5511** to the xStep or xFinal callback routine that implements the aggregate 5512** function. 5513** 5514** This routine must be called from the same thread in which 5515** the aggregate SQL function is running. 5516*/ 5517void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 5518 5519/* 5520** CAPI3REF: User Data For Functions 5521** METHOD: sqlite3_context 5522** 5523** ^The sqlite3_user_data() interface returns a copy of 5524** the pointer that was the pUserData parameter (the 5th parameter) 5525** of the [sqlite3_create_function()] 5526** and [sqlite3_create_function16()] routines that originally 5527** registered the application defined function. 5528** 5529** This routine must be called from the same thread in which 5530** the application-defined function is running. 5531*/ 5532void *sqlite3_user_data(sqlite3_context*); 5533 5534/* 5535** CAPI3REF: Database Connection For Functions 5536** METHOD: sqlite3_context 5537** 5538** ^The sqlite3_context_db_handle() interface returns a copy of 5539** the pointer to the [database connection] (the 1st parameter) 5540** of the [sqlite3_create_function()] 5541** and [sqlite3_create_function16()] routines that originally 5542** registered the application defined function. 5543*/ 5544sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 5545 5546/* 5547** CAPI3REF: Function Auxiliary Data 5548** METHOD: sqlite3_context 5549** 5550** These functions may be used by (non-aggregate) SQL functions to 5551** associate metadata with argument values. If the same value is passed to 5552** multiple invocations of the same SQL function during query execution, under 5553** some circumstances the associated metadata may be preserved. An example 5554** of where this might be useful is in a regular-expression matching 5555** function. The compiled version of the regular expression can be stored as 5556** metadata associated with the pattern string. 5557** Then as long as the pattern string remains the same, 5558** the compiled regular expression can be reused on multiple 5559** invocations of the same function. 5560** 5561** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 5562** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 5563** value to the application-defined function. ^N is zero for the left-most 5564** function argument. ^If there is no metadata 5565** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 5566** returns a NULL pointer. 5567** 5568** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 5569** argument of the application-defined function. ^Subsequent 5570** calls to sqlite3_get_auxdata(C,N) return P from the most recent 5571** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5572** NULL if the metadata has been discarded. 5573** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5574** SQLite will invoke the destructor function X with parameter P exactly 5575** once, when the metadata is discarded. 5576** SQLite is free to discard the metadata at any time, including: <ul> 5577** <li> ^(when the corresponding function parameter changes)^, or 5578** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5579** SQL statement)^, or 5580** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5581** parameter)^, or 5582** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5583** allocation error occurs.)^ </ul> 5584** 5585** Note the last bullet in particular. The destructor X in 5586** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5587** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5588** should be called near the end of the function implementation and the 5589** function implementation should not make any use of P after 5590** sqlite3_set_auxdata() has been called. 5591** 5592** ^(In practice, metadata is preserved between function calls for 5593** function parameters that are compile-time constants, including literal 5594** values and [parameters] and expressions composed from the same.)^ 5595** 5596** The value of the N parameter to these interfaces should be non-negative. 5597** Future enhancements may make use of negative N values to define new 5598** kinds of function caching behavior. 5599** 5600** These routines must be called from the same thread in which 5601** the SQL function is running. 5602*/ 5603void *sqlite3_get_auxdata(sqlite3_context*, int N); 5604void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5605 5606 5607/* 5608** CAPI3REF: Constants Defining Special Destructor Behavior 5609** 5610** These are special values for the destructor that is passed in as the 5611** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5612** argument is SQLITE_STATIC, it means that the content pointer is constant 5613** and will never change. It does not need to be destroyed. ^The 5614** SQLITE_TRANSIENT value means that the content will likely change in 5615** the near future and that SQLite should make its own private copy of 5616** the content before returning. 5617** 5618** The typedef is necessary to work around problems in certain 5619** C++ compilers. 5620*/ 5621typedef void (*sqlite3_destructor_type)(void*); 5622#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5623#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5624 5625/* 5626** CAPI3REF: Setting The Result Of An SQL Function 5627** METHOD: sqlite3_context 5628** 5629** These routines are used by the xFunc or xFinal callbacks that 5630** implement SQL functions and aggregates. See 5631** [sqlite3_create_function()] and [sqlite3_create_function16()] 5632** for additional information. 5633** 5634** These functions work very much like the [parameter binding] family of 5635** functions used to bind values to host parameters in prepared statements. 5636** Refer to the [SQL parameter] documentation for additional information. 5637** 5638** ^The sqlite3_result_blob() interface sets the result from 5639** an application-defined function to be the BLOB whose content is pointed 5640** to by the second parameter and which is N bytes long where N is the 5641** third parameter. 5642** 5643** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5644** interfaces set the result of the application-defined function to be 5645** a BLOB containing all zero bytes and N bytes in size. 5646** 5647** ^The sqlite3_result_double() interface sets the result from 5648** an application-defined function to be a floating point value specified 5649** by its 2nd argument. 5650** 5651** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5652** cause the implemented SQL function to throw an exception. 5653** ^SQLite uses the string pointed to by the 5654** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5655** as the text of an error message. ^SQLite interprets the error 5656** message string from sqlite3_result_error() as UTF-8. ^SQLite 5657** interprets the string from sqlite3_result_error16() as UTF-16 using 5658** the same [byte-order determination rules] as [sqlite3_bind_text16()]. 5659** ^If the third parameter to sqlite3_result_error() 5660** or sqlite3_result_error16() is negative then SQLite takes as the error 5661** message all text up through the first zero character. 5662** ^If the third parameter to sqlite3_result_error() or 5663** sqlite3_result_error16() is non-negative then SQLite takes that many 5664** bytes (not characters) from the 2nd parameter as the error message. 5665** ^The sqlite3_result_error() and sqlite3_result_error16() 5666** routines make a private copy of the error message text before 5667** they return. Hence, the calling function can deallocate or 5668** modify the text after they return without harm. 5669** ^The sqlite3_result_error_code() function changes the error code 5670** returned by SQLite as a result of an error in a function. ^By default, 5671** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5672** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5673** 5674** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5675** error indicating that a string or BLOB is too long to represent. 5676** 5677** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5678** error indicating that a memory allocation failed. 5679** 5680** ^The sqlite3_result_int() interface sets the return value 5681** of the application-defined function to be the 32-bit signed integer 5682** value given in the 2nd argument. 5683** ^The sqlite3_result_int64() interface sets the return value 5684** of the application-defined function to be the 64-bit signed integer 5685** value given in the 2nd argument. 5686** 5687** ^The sqlite3_result_null() interface sets the return value 5688** of the application-defined function to be NULL. 5689** 5690** ^The sqlite3_result_text(), sqlite3_result_text16(), 5691** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5692** set the return value of the application-defined function to be 5693** a text string which is represented as UTF-8, UTF-16 native byte order, 5694** UTF-16 little endian, or UTF-16 big endian, respectively. 5695** ^The sqlite3_result_text64() interface sets the return value of an 5696** application-defined function to be a text string in an encoding 5697** specified by the fifth (and last) parameter, which must be one 5698** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5699** ^SQLite takes the text result from the application from 5700** the 2nd parameter of the sqlite3_result_text* interfaces. 5701** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5702** is negative, then SQLite takes result text from the 2nd parameter 5703** through the first zero character. 5704** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5705** is non-negative, then as many bytes (not characters) of the text 5706** pointed to by the 2nd parameter are taken as the application-defined 5707** function result. If the 3rd parameter is non-negative, then it 5708** must be the byte offset into the string where the NUL terminator would 5709** appear if the string where NUL terminated. If any NUL characters occur 5710** in the string at a byte offset that is less than the value of the 3rd 5711** parameter, then the resulting string will contain embedded NULs and the 5712** result of expressions operating on strings with embedded NULs is undefined. 5713** ^If the 4th parameter to the sqlite3_result_text* interfaces 5714** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5715** function as the destructor on the text or BLOB result when it has 5716** finished using that result. 5717** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5718** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5719** assumes that the text or BLOB result is in constant space and does not 5720** copy the content of the parameter nor call a destructor on the content 5721** when it has finished using that result. 5722** ^If the 4th parameter to the sqlite3_result_text* interfaces 5723** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5724** then SQLite makes a copy of the result into space obtained 5725** from [sqlite3_malloc()] before it returns. 5726** 5727** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and 5728** sqlite3_result_text16be() routines, and for sqlite3_result_text64() 5729** when the encoding is not UTF8, if the input UTF16 begins with a 5730** byte-order mark (BOM, U+FEFF) then the BOM is removed from the 5731** string and the rest of the string is interpreted according to the 5732** byte-order specified by the BOM. ^The byte-order specified by 5733** the BOM at the beginning of the text overrides the byte-order 5734** specified by the interface procedure. ^So, for example, if 5735** sqlite3_result_text16le() is invoked with text that begins 5736** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the 5737** first two bytes of input are skipped and the remaining input 5738** is interpreted as UTF16BE text. 5739** 5740** ^For UTF16 input text to the sqlite3_result_text16(), 5741** sqlite3_result_text16be(), sqlite3_result_text16le(), and 5742** sqlite3_result_text64() routines, if the text contains invalid 5743** UTF16 characters, the invalid characters might be converted 5744** into the unicode replacement character, U+FFFD. 5745** 5746** ^The sqlite3_result_value() interface sets the result of 5747** the application-defined function to be a copy of the 5748** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5749** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5750** so that the [sqlite3_value] specified in the parameter may change or 5751** be deallocated after sqlite3_result_value() returns without harm. 5752** ^A [protected sqlite3_value] object may always be used where an 5753** [unprotected sqlite3_value] object is required, so either 5754** kind of [sqlite3_value] object can be used with this interface. 5755** 5756** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5757** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5758** also associates the host-language pointer P or type T with that 5759** NULL value such that the pointer can be retrieved within an 5760** [application-defined SQL function] using [sqlite3_value_pointer()]. 5761** ^If the D parameter is not NULL, then it is a pointer to a destructor 5762** for the P parameter. ^SQLite invokes D with P as its only argument 5763** when SQLite is finished with P. The T parameter should be a static 5764** string and preferably a string literal. The sqlite3_result_pointer() 5765** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5766** 5767** If these routines are called from within the different thread 5768** than the one containing the application-defined function that received 5769** the [sqlite3_context] pointer, the results are undefined. 5770*/ 5771void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5772void sqlite3_result_blob64(sqlite3_context*,const void*, 5773 sqlite3_uint64,void(*)(void*)); 5774void sqlite3_result_double(sqlite3_context*, double); 5775void sqlite3_result_error(sqlite3_context*, const char*, int); 5776void sqlite3_result_error16(sqlite3_context*, const void*, int); 5777void sqlite3_result_error_toobig(sqlite3_context*); 5778void sqlite3_result_error_nomem(sqlite3_context*); 5779void sqlite3_result_error_code(sqlite3_context*, int); 5780void sqlite3_result_int(sqlite3_context*, int); 5781void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5782void sqlite3_result_null(sqlite3_context*); 5783void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5784void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5785 void(*)(void*), unsigned char encoding); 5786void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5787void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5788void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5789void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5790void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5791void sqlite3_result_zeroblob(sqlite3_context*, int n); 5792int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5793 5794 5795/* 5796** CAPI3REF: Setting The Subtype Of An SQL Function 5797** METHOD: sqlite3_context 5798** 5799** The sqlite3_result_subtype(C,T) function causes the subtype of 5800** the result from the [application-defined SQL function] with 5801** [sqlite3_context] C to be the value T. Only the lower 8 bits 5802** of the subtype T are preserved in current versions of SQLite; 5803** higher order bits are discarded. 5804** The number of subtype bytes preserved by SQLite might increase 5805** in future releases of SQLite. 5806*/ 5807void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5808 5809/* 5810** CAPI3REF: Define New Collating Sequences 5811** METHOD: sqlite3 5812** 5813** ^These functions add, remove, or modify a [collation] associated 5814** with the [database connection] specified as the first argument. 5815** 5816** ^The name of the collation is a UTF-8 string 5817** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5818** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5819** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5820** considered to be the same name. 5821** 5822** ^(The third argument (eTextRep) must be one of the constants: 5823** <ul> 5824** <li> [SQLITE_UTF8], 5825** <li> [SQLITE_UTF16LE], 5826** <li> [SQLITE_UTF16BE], 5827** <li> [SQLITE_UTF16], or 5828** <li> [SQLITE_UTF16_ALIGNED]. 5829** </ul>)^ 5830** ^The eTextRep argument determines the encoding of strings passed 5831** to the collating function callback, xCompare. 5832** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5833** force strings to be UTF16 with native byte order. 5834** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5835** on an even byte address. 5836** 5837** ^The fourth argument, pArg, is an application data pointer that is passed 5838** through as the first argument to the collating function callback. 5839** 5840** ^The fifth argument, xCompare, is a pointer to the collating function. 5841** ^Multiple collating functions can be registered using the same name but 5842** with different eTextRep parameters and SQLite will use whichever 5843** function requires the least amount of data transformation. 5844** ^If the xCompare argument is NULL then the collating function is 5845** deleted. ^When all collating functions having the same name are deleted, 5846** that collation is no longer usable. 5847** 5848** ^The collating function callback is invoked with a copy of the pArg 5849** application data pointer and with two strings in the encoding specified 5850** by the eTextRep argument. The two integer parameters to the collating 5851** function callback are the length of the two strings, in bytes. The collating 5852** function must return an integer that is negative, zero, or positive 5853** if the first string is less than, equal to, or greater than the second, 5854** respectively. A collating function must always return the same answer 5855** given the same inputs. If two or more collating functions are registered 5856** to the same collation name (using different eTextRep values) then all 5857** must give an equivalent answer when invoked with equivalent strings. 5858** The collating function must obey the following properties for all 5859** strings A, B, and C: 5860** 5861** <ol> 5862** <li> If A==B then B==A. 5863** <li> If A==B and B==C then A==C. 5864** <li> If A<B THEN B>A. 5865** <li> If A<B and B<C then A<C. 5866** </ol> 5867** 5868** If a collating function fails any of the above constraints and that 5869** collating function is registered and used, then the behavior of SQLite 5870** is undefined. 5871** 5872** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5873** with the addition that the xDestroy callback is invoked on pArg when 5874** the collating function is deleted. 5875** ^Collating functions are deleted when they are overridden by later 5876** calls to the collation creation functions or when the 5877** [database connection] is closed using [sqlite3_close()]. 5878** 5879** ^The xDestroy callback is <u>not</u> called if the 5880** sqlite3_create_collation_v2() function fails. Applications that invoke 5881** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5882** check the return code and dispose of the application data pointer 5883** themselves rather than expecting SQLite to deal with it for them. 5884** This is different from every other SQLite interface. The inconsistency 5885** is unfortunate but cannot be changed without breaking backwards 5886** compatibility. 5887** 5888** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5889*/ 5890int sqlite3_create_collation( 5891 sqlite3*, 5892 const char *zName, 5893 int eTextRep, 5894 void *pArg, 5895 int(*xCompare)(void*,int,const void*,int,const void*) 5896); 5897int sqlite3_create_collation_v2( 5898 sqlite3*, 5899 const char *zName, 5900 int eTextRep, 5901 void *pArg, 5902 int(*xCompare)(void*,int,const void*,int,const void*), 5903 void(*xDestroy)(void*) 5904); 5905int sqlite3_create_collation16( 5906 sqlite3*, 5907 const void *zName, 5908 int eTextRep, 5909 void *pArg, 5910 int(*xCompare)(void*,int,const void*,int,const void*) 5911); 5912 5913/* 5914** CAPI3REF: Collation Needed Callbacks 5915** METHOD: sqlite3 5916** 5917** ^To avoid having to register all collation sequences before a database 5918** can be used, a single callback function may be registered with the 5919** [database connection] to be invoked whenever an undefined collation 5920** sequence is required. 5921** 5922** ^If the function is registered using the sqlite3_collation_needed() API, 5923** then it is passed the names of undefined collation sequences as strings 5924** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5925** the names are passed as UTF-16 in machine native byte order. 5926** ^A call to either function replaces the existing collation-needed callback. 5927** 5928** ^(When the callback is invoked, the first argument passed is a copy 5929** of the second argument to sqlite3_collation_needed() or 5930** sqlite3_collation_needed16(). The second argument is the database 5931** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5932** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5933** sequence function required. The fourth parameter is the name of the 5934** required collation sequence.)^ 5935** 5936** The callback function should register the desired collation using 5937** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5938** [sqlite3_create_collation_v2()]. 5939*/ 5940int sqlite3_collation_needed( 5941 sqlite3*, 5942 void*, 5943 void(*)(void*,sqlite3*,int eTextRep,const char*) 5944); 5945int sqlite3_collation_needed16( 5946 sqlite3*, 5947 void*, 5948 void(*)(void*,sqlite3*,int eTextRep,const void*) 5949); 5950 5951#ifdef SQLITE_ENABLE_CEROD 5952/* 5953** Specify the activation key for a CEROD database. Unless 5954** activated, none of the CEROD routines will work. 5955*/ 5956void sqlite3_activate_cerod( 5957 const char *zPassPhrase /* Activation phrase */ 5958); 5959#endif 5960 5961/* 5962** CAPI3REF: Suspend Execution For A Short Time 5963** 5964** The sqlite3_sleep() function causes the current thread to suspend execution 5965** for at least a number of milliseconds specified in its parameter. 5966** 5967** If the operating system does not support sleep requests with 5968** millisecond time resolution, then the time will be rounded up to 5969** the nearest second. The number of milliseconds of sleep actually 5970** requested from the operating system is returned. 5971** 5972** ^SQLite implements this interface by calling the xSleep() 5973** method of the default [sqlite3_vfs] object. If the xSleep() method 5974** of the default VFS is not implemented correctly, or not implemented at 5975** all, then the behavior of sqlite3_sleep() may deviate from the description 5976** in the previous paragraphs. 5977*/ 5978int sqlite3_sleep(int); 5979 5980/* 5981** CAPI3REF: Name Of The Folder Holding Temporary Files 5982** 5983** ^(If this global variable is made to point to a string which is 5984** the name of a folder (a.k.a. directory), then all temporary files 5985** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5986** will be placed in that directory.)^ ^If this variable 5987** is a NULL pointer, then SQLite performs a search for an appropriate 5988** temporary file directory. 5989** 5990** Applications are strongly discouraged from using this global variable. 5991** It is required to set a temporary folder on Windows Runtime (WinRT). 5992** But for all other platforms, it is highly recommended that applications 5993** neither read nor write this variable. This global variable is a relic 5994** that exists for backwards compatibility of legacy applications and should 5995** be avoided in new projects. 5996** 5997** It is not safe to read or modify this variable in more than one 5998** thread at a time. It is not safe to read or modify this variable 5999** if a [database connection] is being used at the same time in a separate 6000** thread. 6001** It is intended that this variable be set once 6002** as part of process initialization and before any SQLite interface 6003** routines have been called and that this variable remain unchanged 6004** thereafter. 6005** 6006** ^The [temp_store_directory pragma] may modify this variable and cause 6007** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6008** the [temp_store_directory pragma] always assumes that any string 6009** that this variable points to is held in memory obtained from 6010** [sqlite3_malloc] and the pragma may attempt to free that memory 6011** using [sqlite3_free]. 6012** Hence, if this variable is modified directly, either it should be 6013** made NULL or made to point to memory obtained from [sqlite3_malloc] 6014** or else the use of the [temp_store_directory pragma] should be avoided. 6015** Except when requested by the [temp_store_directory pragma], SQLite 6016** does not free the memory that sqlite3_temp_directory points to. If 6017** the application wants that memory to be freed, it must do 6018** so itself, taking care to only do so after all [database connection] 6019** objects have been destroyed. 6020** 6021** <b>Note to Windows Runtime users:</b> The temporary directory must be set 6022** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 6023** features that require the use of temporary files may fail. Here is an 6024** example of how to do this using C++ with the Windows Runtime: 6025** 6026** <blockquote><pre> 6027** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 6028** TemporaryFolder->Path->Data(); 6029** char zPathBuf[MAX_PATH + 1]; 6030** memset(zPathBuf, 0, sizeof(zPathBuf)); 6031** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 6032** NULL, NULL); 6033** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 6034** </pre></blockquote> 6035*/ 6036SQLITE_EXTERN char *sqlite3_temp_directory; 6037 6038/* 6039** CAPI3REF: Name Of The Folder Holding Database Files 6040** 6041** ^(If this global variable is made to point to a string which is 6042** the name of a folder (a.k.a. directory), then all database files 6043** specified with a relative pathname and created or accessed by 6044** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 6045** to be relative to that directory.)^ ^If this variable is a NULL 6046** pointer, then SQLite assumes that all database files specified 6047** with a relative pathname are relative to the current directory 6048** for the process. Only the windows VFS makes use of this global 6049** variable; it is ignored by the unix VFS. 6050** 6051** Changing the value of this variable while a database connection is 6052** open can result in a corrupt database. 6053** 6054** It is not safe to read or modify this variable in more than one 6055** thread at a time. It is not safe to read or modify this variable 6056** if a [database connection] is being used at the same time in a separate 6057** thread. 6058** It is intended that this variable be set once 6059** as part of process initialization and before any SQLite interface 6060** routines have been called and that this variable remain unchanged 6061** thereafter. 6062** 6063** ^The [data_store_directory pragma] may modify this variable and cause 6064** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6065** the [data_store_directory pragma] always assumes that any string 6066** that this variable points to is held in memory obtained from 6067** [sqlite3_malloc] and the pragma may attempt to free that memory 6068** using [sqlite3_free]. 6069** Hence, if this variable is modified directly, either it should be 6070** made NULL or made to point to memory obtained from [sqlite3_malloc] 6071** or else the use of the [data_store_directory pragma] should be avoided. 6072*/ 6073SQLITE_EXTERN char *sqlite3_data_directory; 6074 6075/* 6076** CAPI3REF: Win32 Specific Interface 6077** 6078** These interfaces are available only on Windows. The 6079** [sqlite3_win32_set_directory] interface is used to set the value associated 6080** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to 6081** zValue, depending on the value of the type parameter. The zValue parameter 6082** should be NULL to cause the previous value to be freed via [sqlite3_free]; 6083** a non-NULL value will be copied into memory obtained from [sqlite3_malloc] 6084** prior to being used. The [sqlite3_win32_set_directory] interface returns 6085** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported, 6086** or [SQLITE_NOMEM] if memory could not be allocated. The value of the 6087** [sqlite3_data_directory] variable is intended to act as a replacement for 6088** the current directory on the sub-platforms of Win32 where that concept is 6089** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and 6090** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the 6091** sqlite3_win32_set_directory interface except the string parameter must be 6092** UTF-8 or UTF-16, respectively. 6093*/ 6094int sqlite3_win32_set_directory( 6095 unsigned long type, /* Identifier for directory being set or reset */ 6096 void *zValue /* New value for directory being set or reset */ 6097); 6098int sqlite3_win32_set_directory8(unsigned long type, const char *zValue); 6099int sqlite3_win32_set_directory16(unsigned long type, const void *zValue); 6100 6101/* 6102** CAPI3REF: Win32 Directory Types 6103** 6104** These macros are only available on Windows. They define the allowed values 6105** for the type argument to the [sqlite3_win32_set_directory] interface. 6106*/ 6107#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1 6108#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2 6109 6110/* 6111** CAPI3REF: Test For Auto-Commit Mode 6112** KEYWORDS: {autocommit mode} 6113** METHOD: sqlite3 6114** 6115** ^The sqlite3_get_autocommit() interface returns non-zero or 6116** zero if the given database connection is or is not in autocommit mode, 6117** respectively. ^Autocommit mode is on by default. 6118** ^Autocommit mode is disabled by a [BEGIN] statement. 6119** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 6120** 6121** If certain kinds of errors occur on a statement within a multi-statement 6122** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 6123** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 6124** transaction might be rolled back automatically. The only way to 6125** find out whether SQLite automatically rolled back the transaction after 6126** an error is to use this function. 6127** 6128** If another thread changes the autocommit status of the database 6129** connection while this routine is running, then the return value 6130** is undefined. 6131*/ 6132int sqlite3_get_autocommit(sqlite3*); 6133 6134/* 6135** CAPI3REF: Find The Database Handle Of A Prepared Statement 6136** METHOD: sqlite3_stmt 6137** 6138** ^The sqlite3_db_handle interface returns the [database connection] handle 6139** to which a [prepared statement] belongs. ^The [database connection] 6140** returned by sqlite3_db_handle is the same [database connection] 6141** that was the first argument 6142** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 6143** create the statement in the first place. 6144*/ 6145sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 6146 6147/* 6148** CAPI3REF: Return The Filename For A Database Connection 6149** METHOD: sqlite3 6150** 6151** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename 6152** associated with database N of connection D. 6153** ^If there is no attached database N on the database 6154** connection D, or if database N is a temporary or in-memory database, then 6155** this function will return either a NULL pointer or an empty string. 6156** 6157** ^The string value returned by this routine is owned and managed by 6158** the database connection. ^The value will be valid until the database N 6159** is [DETACH]-ed or until the database connection closes. 6160** 6161** ^The filename returned by this function is the output of the 6162** xFullPathname method of the [VFS]. ^In other words, the filename 6163** will be an absolute pathname, even if the filename used 6164** to open the database originally was a URI or relative pathname. 6165** 6166** If the filename pointer returned by this routine is not NULL, then it 6167** can be used as the filename input parameter to these routines: 6168** <ul> 6169** <li> [sqlite3_uri_parameter()] 6170** <li> [sqlite3_uri_boolean()] 6171** <li> [sqlite3_uri_int64()] 6172** <li> [sqlite3_filename_database()] 6173** <li> [sqlite3_filename_journal()] 6174** <li> [sqlite3_filename_wal()] 6175** </ul> 6176*/ 6177const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 6178 6179/* 6180** CAPI3REF: Determine if a database is read-only 6181** METHOD: sqlite3 6182** 6183** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 6184** of connection D is read-only, 0 if it is read/write, or -1 if N is not 6185** the name of a database on connection D. 6186*/ 6187int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 6188 6189/* 6190** CAPI3REF: Determine the transaction state of a database 6191** METHOD: sqlite3 6192** 6193** ^The sqlite3_txn_state(D,S) interface returns the current 6194** [transaction state] of schema S in database connection D. ^If S is NULL, 6195** then the highest transaction state of any schema on databse connection D 6196** is returned. Transaction states are (in order of lowest to highest): 6197** <ol> 6198** <li value="0"> SQLITE_TXN_NONE 6199** <li value="1"> SQLITE_TXN_READ 6200** <li value="2"> SQLITE_TXN_WRITE 6201** </ol> 6202** ^If the S argument to sqlite3_txn_state(D,S) is not the name of 6203** a valid schema, then -1 is returned. 6204*/ 6205int sqlite3_txn_state(sqlite3*,const char *zSchema); 6206 6207/* 6208** CAPI3REF: Allowed return values from [sqlite3_txn_state()] 6209** KEYWORDS: {transaction state} 6210** 6211** These constants define the current transaction state of a database file. 6212** ^The [sqlite3_txn_state(D,S)] interface returns one of these 6213** constants in order to describe the transaction state of schema S 6214** in [database connection] D. 6215** 6216** <dl> 6217** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt> 6218** <dd>The SQLITE_TXN_NONE state means that no transaction is currently 6219** pending.</dd> 6220** 6221** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt> 6222** <dd>The SQLITE_TXN_READ state means that the database is currently 6223** in a read transaction. Content has been read from the database file 6224** but nothing in the database file has changed. The transaction state 6225** will advanced to SQLITE_TXN_WRITE if any changes occur and there are 6226** no other conflicting concurrent write transactions. The transaction 6227** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or 6228** [COMMIT].</dd> 6229** 6230** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt> 6231** <dd>The SQLITE_TXN_WRITE state means that the database is currently 6232** in a write transaction. Content has been written to the database file 6233** but has not yet committed. The transaction state will change to 6234** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd> 6235*/ 6236#define SQLITE_TXN_NONE 0 6237#define SQLITE_TXN_READ 1 6238#define SQLITE_TXN_WRITE 2 6239 6240/* 6241** CAPI3REF: Find the next prepared statement 6242** METHOD: sqlite3 6243** 6244** ^This interface returns a pointer to the next [prepared statement] after 6245** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 6246** then this interface returns a pointer to the first prepared statement 6247** associated with the database connection pDb. ^If no prepared statement 6248** satisfies the conditions of this routine, it returns NULL. 6249** 6250** The [database connection] pointer D in a call to 6251** [sqlite3_next_stmt(D,S)] must refer to an open database 6252** connection and in particular must not be a NULL pointer. 6253*/ 6254sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 6255 6256/* 6257** CAPI3REF: Commit And Rollback Notification Callbacks 6258** METHOD: sqlite3 6259** 6260** ^The sqlite3_commit_hook() interface registers a callback 6261** function to be invoked whenever a transaction is [COMMIT | committed]. 6262** ^Any callback set by a previous call to sqlite3_commit_hook() 6263** for the same database connection is overridden. 6264** ^The sqlite3_rollback_hook() interface registers a callback 6265** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 6266** ^Any callback set by a previous call to sqlite3_rollback_hook() 6267** for the same database connection is overridden. 6268** ^The pArg argument is passed through to the callback. 6269** ^If the callback on a commit hook function returns non-zero, 6270** then the commit is converted into a rollback. 6271** 6272** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 6273** return the P argument from the previous call of the same function 6274** on the same [database connection] D, or NULL for 6275** the first call for each function on D. 6276** 6277** The commit and rollback hook callbacks are not reentrant. 6278** The callback implementation must not do anything that will modify 6279** the database connection that invoked the callback. Any actions 6280** to modify the database connection must be deferred until after the 6281** completion of the [sqlite3_step()] call that triggered the commit 6282** or rollback hook in the first place. 6283** Note that running any other SQL statements, including SELECT statements, 6284** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 6285** the database connections for the meaning of "modify" in this paragraph. 6286** 6287** ^Registering a NULL function disables the callback. 6288** 6289** ^When the commit hook callback routine returns zero, the [COMMIT] 6290** operation is allowed to continue normally. ^If the commit hook 6291** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 6292** ^The rollback hook is invoked on a rollback that results from a commit 6293** hook returning non-zero, just as it would be with any other rollback. 6294** 6295** ^For the purposes of this API, a transaction is said to have been 6296** rolled back if an explicit "ROLLBACK" statement is executed, or 6297** an error or constraint causes an implicit rollback to occur. 6298** ^The rollback callback is not invoked if a transaction is 6299** automatically rolled back because the database connection is closed. 6300** 6301** See also the [sqlite3_update_hook()] interface. 6302*/ 6303void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 6304void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 6305 6306/* 6307** CAPI3REF: Data Change Notification Callbacks 6308** METHOD: sqlite3 6309** 6310** ^The sqlite3_update_hook() interface registers a callback function 6311** with the [database connection] identified by the first argument 6312** to be invoked whenever a row is updated, inserted or deleted in 6313** a [rowid table]. 6314** ^Any callback set by a previous call to this function 6315** for the same database connection is overridden. 6316** 6317** ^The second argument is a pointer to the function to invoke when a 6318** row is updated, inserted or deleted in a rowid table. 6319** ^The first argument to the callback is a copy of the third argument 6320** to sqlite3_update_hook(). 6321** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 6322** or [SQLITE_UPDATE], depending on the operation that caused the callback 6323** to be invoked. 6324** ^The third and fourth arguments to the callback contain pointers to the 6325** database and table name containing the affected row. 6326** ^The final callback parameter is the [rowid] of the row. 6327** ^In the case of an update, this is the [rowid] after the update takes place. 6328** 6329** ^(The update hook is not invoked when internal system tables are 6330** modified (i.e. sqlite_sequence).)^ 6331** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 6332** 6333** ^In the current implementation, the update hook 6334** is not invoked when conflicting rows are deleted because of an 6335** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 6336** invoked when rows are deleted using the [truncate optimization]. 6337** The exceptions defined in this paragraph might change in a future 6338** release of SQLite. 6339** 6340** The update hook implementation must not do anything that will modify 6341** the database connection that invoked the update hook. Any actions 6342** to modify the database connection must be deferred until after the 6343** completion of the [sqlite3_step()] call that triggered the update hook. 6344** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 6345** database connections for the meaning of "modify" in this paragraph. 6346** 6347** ^The sqlite3_update_hook(D,C,P) function 6348** returns the P argument from the previous call 6349** on the same [database connection] D, or NULL for 6350** the first call on D. 6351** 6352** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 6353** and [sqlite3_preupdate_hook()] interfaces. 6354*/ 6355void *sqlite3_update_hook( 6356 sqlite3*, 6357 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 6358 void* 6359); 6360 6361/* 6362** CAPI3REF: Enable Or Disable Shared Pager Cache 6363** 6364** ^(This routine enables or disables the sharing of the database cache 6365** and schema data structures between [database connection | connections] 6366** to the same database. Sharing is enabled if the argument is true 6367** and disabled if the argument is false.)^ 6368** 6369** ^Cache sharing is enabled and disabled for an entire process. 6370** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 6371** In prior versions of SQLite, 6372** sharing was enabled or disabled for each thread separately. 6373** 6374** ^(The cache sharing mode set by this interface effects all subsequent 6375** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 6376** Existing database connections continue to use the sharing mode 6377** that was in effect at the time they were opened.)^ 6378** 6379** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 6380** successfully. An [error code] is returned otherwise.)^ 6381** 6382** ^Shared cache is disabled by default. It is recommended that it stay 6383** that way. In other words, do not use this routine. This interface 6384** continues to be provided for historical compatibility, but its use is 6385** discouraged. Any use of shared cache is discouraged. If shared cache 6386** must be used, it is recommended that shared cache only be enabled for 6387** individual database connections using the [sqlite3_open_v2()] interface 6388** with the [SQLITE_OPEN_SHAREDCACHE] flag. 6389** 6390** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 6391** and will always return SQLITE_MISUSE. On those systems, 6392** shared cache mode should be enabled per-database connection via 6393** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 6394** 6395** This interface is threadsafe on processors where writing a 6396** 32-bit integer is atomic. 6397** 6398** See Also: [SQLite Shared-Cache Mode] 6399*/ 6400int sqlite3_enable_shared_cache(int); 6401 6402/* 6403** CAPI3REF: Attempt To Free Heap Memory 6404** 6405** ^The sqlite3_release_memory() interface attempts to free N bytes 6406** of heap memory by deallocating non-essential memory allocations 6407** held by the database library. Memory used to cache database 6408** pages to improve performance is an example of non-essential memory. 6409** ^sqlite3_release_memory() returns the number of bytes actually freed, 6410** which might be more or less than the amount requested. 6411** ^The sqlite3_release_memory() routine is a no-op returning zero 6412** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 6413** 6414** See also: [sqlite3_db_release_memory()] 6415*/ 6416int sqlite3_release_memory(int); 6417 6418/* 6419** CAPI3REF: Free Memory Used By A Database Connection 6420** METHOD: sqlite3 6421** 6422** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 6423** memory as possible from database connection D. Unlike the 6424** [sqlite3_release_memory()] interface, this interface is in effect even 6425** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 6426** omitted. 6427** 6428** See also: [sqlite3_release_memory()] 6429*/ 6430int sqlite3_db_release_memory(sqlite3*); 6431 6432/* 6433** CAPI3REF: Impose A Limit On Heap Size 6434** 6435** These interfaces impose limits on the amount of heap memory that will be 6436** by all database connections within a single process. 6437** 6438** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 6439** soft limit on the amount of heap memory that may be allocated by SQLite. 6440** ^SQLite strives to keep heap memory utilization below the soft heap 6441** limit by reducing the number of pages held in the page cache 6442** as heap memory usages approaches the limit. 6443** ^The soft heap limit is "soft" because even though SQLite strives to stay 6444** below the limit, it will exceed the limit rather than generate 6445** an [SQLITE_NOMEM] error. In other words, the soft heap limit 6446** is advisory only. 6447** 6448** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of 6449** N bytes on the amount of memory that will be allocated. ^The 6450** sqlite3_hard_heap_limit64(N) interface is similar to 6451** sqlite3_soft_heap_limit64(N) except that memory allocations will fail 6452** when the hard heap limit is reached. 6453** 6454** ^The return value from both sqlite3_soft_heap_limit64() and 6455** sqlite3_hard_heap_limit64() is the size of 6456** the heap limit prior to the call, or negative in the case of an 6457** error. ^If the argument N is negative 6458** then no change is made to the heap limit. Hence, the current 6459** size of heap limits can be determined by invoking 6460** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1). 6461** 6462** ^Setting the heap limits to zero disables the heap limiter mechanism. 6463** 6464** ^The soft heap limit may not be greater than the hard heap limit. 6465** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N) 6466** is invoked with a value of N that is greater than the hard heap limit, 6467** the the soft heap limit is set to the value of the hard heap limit. 6468** ^The soft heap limit is automatically enabled whenever the hard heap 6469** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and 6470** the soft heap limit is outside the range of 1..N, then the soft heap 6471** limit is set to N. ^Invoking sqlite3_soft_heap_limit64(0) when the 6472** hard heap limit is enabled makes the soft heap limit equal to the 6473** hard heap limit. 6474** 6475** The memory allocation limits can also be adjusted using 6476** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit]. 6477** 6478** ^(The heap limits are not enforced in the current implementation 6479** if one or more of following conditions are true: 6480** 6481** <ul> 6482** <li> The limit value is set to zero. 6483** <li> Memory accounting is disabled using a combination of the 6484** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 6485** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 6486** <li> An alternative page cache implementation is specified using 6487** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 6488** <li> The page cache allocates from its own memory pool supplied 6489** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 6490** from the heap. 6491** </ul>)^ 6492** 6493** The circumstances under which SQLite will enforce the heap limits may 6494** changes in future releases of SQLite. 6495*/ 6496sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 6497sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N); 6498 6499/* 6500** CAPI3REF: Deprecated Soft Heap Limit Interface 6501** DEPRECATED 6502** 6503** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 6504** interface. This routine is provided for historical compatibility 6505** only. All new applications should use the 6506** [sqlite3_soft_heap_limit64()] interface rather than this one. 6507*/ 6508SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 6509 6510 6511/* 6512** CAPI3REF: Extract Metadata About A Column Of A Table 6513** METHOD: sqlite3 6514** 6515** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 6516** information about column C of table T in database D 6517** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 6518** interface returns SQLITE_OK and fills in the non-NULL pointers in 6519** the final five arguments with appropriate values if the specified 6520** column exists. ^The sqlite3_table_column_metadata() interface returns 6521** SQLITE_ERROR if the specified column does not exist. 6522** ^If the column-name parameter to sqlite3_table_column_metadata() is a 6523** NULL pointer, then this routine simply checks for the existence of the 6524** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 6525** does not. If the table name parameter T in a call to 6526** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 6527** undefined behavior. 6528** 6529** ^The column is identified by the second, third and fourth parameters to 6530** this function. ^(The second parameter is either the name of the database 6531** (i.e. "main", "temp", or an attached database) containing the specified 6532** table or NULL.)^ ^If it is NULL, then all attached databases are searched 6533** for the table using the same algorithm used by the database engine to 6534** resolve unqualified table references. 6535** 6536** ^The third and fourth parameters to this function are the table and column 6537** name of the desired column, respectively. 6538** 6539** ^Metadata is returned by writing to the memory locations passed as the 5th 6540** and subsequent parameters to this function. ^Any of these arguments may be 6541** NULL, in which case the corresponding element of metadata is omitted. 6542** 6543** ^(<blockquote> 6544** <table border="1"> 6545** <tr><th> Parameter <th> Output<br>Type <th> Description 6546** 6547** <tr><td> 5th <td> const char* <td> Data type 6548** <tr><td> 6th <td> const char* <td> Name of default collation sequence 6549** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 6550** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 6551** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 6552** </table> 6553** </blockquote>)^ 6554** 6555** ^The memory pointed to by the character pointers returned for the 6556** declaration type and collation sequence is valid until the next 6557** call to any SQLite API function. 6558** 6559** ^If the specified table is actually a view, an [error code] is returned. 6560** 6561** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 6562** is not a [WITHOUT ROWID] table and an 6563** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 6564** parameters are set for the explicitly declared column. ^(If there is no 6565** [INTEGER PRIMARY KEY] column, then the outputs 6566** for the [rowid] are set as follows: 6567** 6568** <pre> 6569** data type: "INTEGER" 6570** collation sequence: "BINARY" 6571** not null: 0 6572** primary key: 1 6573** auto increment: 0 6574** </pre>)^ 6575** 6576** ^This function causes all database schemas to be read from disk and 6577** parsed, if that has not already been done, and returns an error if 6578** any errors are encountered while loading the schema. 6579*/ 6580int sqlite3_table_column_metadata( 6581 sqlite3 *db, /* Connection handle */ 6582 const char *zDbName, /* Database name or NULL */ 6583 const char *zTableName, /* Table name */ 6584 const char *zColumnName, /* Column name */ 6585 char const **pzDataType, /* OUTPUT: Declared data type */ 6586 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 6587 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 6588 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 6589 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 6590); 6591 6592/* 6593** CAPI3REF: Load An Extension 6594** METHOD: sqlite3 6595** 6596** ^This interface loads an SQLite extension library from the named file. 6597** 6598** ^The sqlite3_load_extension() interface attempts to load an 6599** [SQLite extension] library contained in the file zFile. If 6600** the file cannot be loaded directly, attempts are made to load 6601** with various operating-system specific extensions added. 6602** So for example, if "samplelib" cannot be loaded, then names like 6603** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 6604** be tried also. 6605** 6606** ^The entry point is zProc. 6607** ^(zProc may be 0, in which case SQLite will try to come up with an 6608** entry point name on its own. It first tries "sqlite3_extension_init". 6609** If that does not work, it constructs a name "sqlite3_X_init" where the 6610** X is consists of the lower-case equivalent of all ASCII alphabetic 6611** characters in the filename from the last "/" to the first following 6612** "." and omitting any initial "lib".)^ 6613** ^The sqlite3_load_extension() interface returns 6614** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 6615** ^If an error occurs and pzErrMsg is not 0, then the 6616** [sqlite3_load_extension()] interface shall attempt to 6617** fill *pzErrMsg with error message text stored in memory 6618** obtained from [sqlite3_malloc()]. The calling function 6619** should free this memory by calling [sqlite3_free()]. 6620** 6621** ^Extension loading must be enabled using 6622** [sqlite3_enable_load_extension()] or 6623** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 6624** prior to calling this API, 6625** otherwise an error will be returned. 6626** 6627** <b>Security warning:</b> It is recommended that the 6628** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 6629** interface. The use of the [sqlite3_enable_load_extension()] interface 6630** should be avoided. This will keep the SQL function [load_extension()] 6631** disabled and prevent SQL injections from giving attackers 6632** access to extension loading capabilities. 6633** 6634** See also the [load_extension() SQL function]. 6635*/ 6636int sqlite3_load_extension( 6637 sqlite3 *db, /* Load the extension into this database connection */ 6638 const char *zFile, /* Name of the shared library containing extension */ 6639 const char *zProc, /* Entry point. Derived from zFile if 0 */ 6640 char **pzErrMsg /* Put error message here if not 0 */ 6641); 6642 6643/* 6644** CAPI3REF: Enable Or Disable Extension Loading 6645** METHOD: sqlite3 6646** 6647** ^So as not to open security holes in older applications that are 6648** unprepared to deal with [extension loading], and as a means of disabling 6649** [extension loading] while evaluating user-entered SQL, the following API 6650** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 6651** 6652** ^Extension loading is off by default. 6653** ^Call the sqlite3_enable_load_extension() routine with onoff==1 6654** to turn extension loading on and call it with onoff==0 to turn 6655** it back off again. 6656** 6657** ^This interface enables or disables both the C-API 6658** [sqlite3_load_extension()] and the SQL function [load_extension()]. 6659** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 6660** to enable or disable only the C-API.)^ 6661** 6662** <b>Security warning:</b> It is recommended that extension loading 6663** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 6664** rather than this interface, so the [load_extension()] SQL function 6665** remains disabled. This will prevent SQL injections from giving attackers 6666** access to extension loading capabilities. 6667*/ 6668int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6669 6670/* 6671** CAPI3REF: Automatically Load Statically Linked Extensions 6672** 6673** ^This interface causes the xEntryPoint() function to be invoked for 6674** each new [database connection] that is created. The idea here is that 6675** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6676** that is to be automatically loaded into all new database connections. 6677** 6678** ^(Even though the function prototype shows that xEntryPoint() takes 6679** no arguments and returns void, SQLite invokes xEntryPoint() with three 6680** arguments and expects an integer result as if the signature of the 6681** entry point where as follows: 6682** 6683** <blockquote><pre> 6684** int xEntryPoint( 6685** sqlite3 *db, 6686** const char **pzErrMsg, 6687** const struct sqlite3_api_routines *pThunk 6688** ); 6689** </pre></blockquote>)^ 6690** 6691** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6692** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6693** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6694** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6695** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6696** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6697** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6698** 6699** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6700** on the list of automatic extensions is a harmless no-op. ^No entry point 6701** will be called more than once for each database connection that is opened. 6702** 6703** See also: [sqlite3_reset_auto_extension()] 6704** and [sqlite3_cancel_auto_extension()] 6705*/ 6706int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6707 6708/* 6709** CAPI3REF: Cancel Automatic Extension Loading 6710** 6711** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6712** initialization routine X that was registered using a prior call to 6713** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6714** routine returns 1 if initialization routine X was successfully 6715** unregistered and it returns 0 if X was not on the list of initialization 6716** routines. 6717*/ 6718int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6719 6720/* 6721** CAPI3REF: Reset Automatic Extension Loading 6722** 6723** ^This interface disables all automatic extensions previously 6724** registered using [sqlite3_auto_extension()]. 6725*/ 6726void sqlite3_reset_auto_extension(void); 6727 6728/* 6729** The interface to the virtual-table mechanism is currently considered 6730** to be experimental. The interface might change in incompatible ways. 6731** If this is a problem for you, do not use the interface at this time. 6732** 6733** When the virtual-table mechanism stabilizes, we will declare the 6734** interface fixed, support it indefinitely, and remove this comment. 6735*/ 6736 6737/* 6738** Structures used by the virtual table interface 6739*/ 6740typedef struct sqlite3_vtab sqlite3_vtab; 6741typedef struct sqlite3_index_info sqlite3_index_info; 6742typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6743typedef struct sqlite3_module sqlite3_module; 6744 6745/* 6746** CAPI3REF: Virtual Table Object 6747** KEYWORDS: sqlite3_module {virtual table module} 6748** 6749** This structure, sometimes called a "virtual table module", 6750** defines the implementation of a [virtual table]. 6751** This structure consists mostly of methods for the module. 6752** 6753** ^A virtual table module is created by filling in a persistent 6754** instance of this structure and passing a pointer to that instance 6755** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6756** ^The registration remains valid until it is replaced by a different 6757** module or until the [database connection] closes. The content 6758** of this structure must not change while it is registered with 6759** any database connection. 6760*/ 6761struct sqlite3_module { 6762 int iVersion; 6763 int (*xCreate)(sqlite3*, void *pAux, 6764 int argc, const char *const*argv, 6765 sqlite3_vtab **ppVTab, char**); 6766 int (*xConnect)(sqlite3*, void *pAux, 6767 int argc, const char *const*argv, 6768 sqlite3_vtab **ppVTab, char**); 6769 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6770 int (*xDisconnect)(sqlite3_vtab *pVTab); 6771 int (*xDestroy)(sqlite3_vtab *pVTab); 6772 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6773 int (*xClose)(sqlite3_vtab_cursor*); 6774 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6775 int argc, sqlite3_value **argv); 6776 int (*xNext)(sqlite3_vtab_cursor*); 6777 int (*xEof)(sqlite3_vtab_cursor*); 6778 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6779 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6780 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6781 int (*xBegin)(sqlite3_vtab *pVTab); 6782 int (*xSync)(sqlite3_vtab *pVTab); 6783 int (*xCommit)(sqlite3_vtab *pVTab); 6784 int (*xRollback)(sqlite3_vtab *pVTab); 6785 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6786 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6787 void **ppArg); 6788 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6789 /* The methods above are in version 1 of the sqlite_module object. Those 6790 ** below are for version 2 and greater. */ 6791 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6792 int (*xRelease)(sqlite3_vtab *pVTab, int); 6793 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6794 /* The methods above are in versions 1 and 2 of the sqlite_module object. 6795 ** Those below are for version 3 and greater. */ 6796 int (*xShadowName)(const char*); 6797}; 6798 6799/* 6800** CAPI3REF: Virtual Table Indexing Information 6801** KEYWORDS: sqlite3_index_info 6802** 6803** The sqlite3_index_info structure and its substructures is used as part 6804** of the [virtual table] interface to 6805** pass information into and receive the reply from the [xBestIndex] 6806** method of a [virtual table module]. The fields under **Inputs** are the 6807** inputs to xBestIndex and are read-only. xBestIndex inserts its 6808** results into the **Outputs** fields. 6809** 6810** ^(The aConstraint[] array records WHERE clause constraints of the form: 6811** 6812** <blockquote>column OP expr</blockquote> 6813** 6814** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6815** stored in aConstraint[].op using one of the 6816** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6817** ^(The index of the column is stored in 6818** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6819** expr on the right-hand side can be evaluated (and thus the constraint 6820** is usable) and false if it cannot.)^ 6821** 6822** ^The optimizer automatically inverts terms of the form "expr OP column" 6823** and makes other simplifications to the WHERE clause in an attempt to 6824** get as many WHERE clause terms into the form shown above as possible. 6825** ^The aConstraint[] array only reports WHERE clause terms that are 6826** relevant to the particular virtual table being queried. 6827** 6828** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6829** ^Each term of aOrderBy records a column of the ORDER BY clause. 6830** 6831** The colUsed field indicates which columns of the virtual table may be 6832** required by the current scan. Virtual table columns are numbered from 6833** zero in the order in which they appear within the CREATE TABLE statement 6834** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6835** the corresponding bit is set within the colUsed mask if the column may be 6836** required by SQLite. If the table has at least 64 columns and any column 6837** to the right of the first 63 is required, then bit 63 of colUsed is also 6838** set. In other words, column iCol may be required if the expression 6839** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6840** non-zero. 6841** 6842** The [xBestIndex] method must fill aConstraintUsage[] with information 6843** about what parameters to pass to xFilter. ^If argvIndex>0 then 6844** the right-hand side of the corresponding aConstraint[] is evaluated 6845** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6846** is true, then the constraint is assumed to be fully handled by the 6847** virtual table and might not be checked again by the byte code.)^ ^(The 6848** aConstraintUsage[].omit flag is an optimization hint. When the omit flag 6849** is left in its default setting of false, the constraint will always be 6850** checked separately in byte code. If the omit flag is change to true, then 6851** the constraint may or may not be checked in byte code. In other words, 6852** when the omit flag is true there is no guarantee that the constraint will 6853** not be checked again using byte code.)^ 6854** 6855** ^The idxNum and idxPtr values are recorded and passed into the 6856** [xFilter] method. 6857** ^[sqlite3_free()] is used to free idxPtr if and only if 6858** needToFreeIdxPtr is true. 6859** 6860** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6861** the correct order to satisfy the ORDER BY clause so that no separate 6862** sorting step is required. 6863** 6864** ^The estimatedCost value is an estimate of the cost of a particular 6865** strategy. A cost of N indicates that the cost of the strategy is similar 6866** to a linear scan of an SQLite table with N rows. A cost of log(N) 6867** indicates that the expense of the operation is similar to that of a 6868** binary search on a unique indexed field of an SQLite table with N rows. 6869** 6870** ^The estimatedRows value is an estimate of the number of rows that 6871** will be returned by the strategy. 6872** 6873** The xBestIndex method may optionally populate the idxFlags field with a 6874** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6875** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6876** assumes that the strategy may visit at most one row. 6877** 6878** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6879** SQLite also assumes that if a call to the xUpdate() method is made as 6880** part of the same statement to delete or update a virtual table row and the 6881** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6882** any database changes. In other words, if the xUpdate() returns 6883** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6884** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6885** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6886** the xUpdate method are automatically rolled back by SQLite. 6887** 6888** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6889** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6890** If a virtual table extension is 6891** used with an SQLite version earlier than 3.8.2, the results of attempting 6892** to read or write the estimatedRows field are undefined (but are likely 6893** to include crashing the application). The estimatedRows field should 6894** therefore only be used if [sqlite3_libversion_number()] returns a 6895** value greater than or equal to 3008002. Similarly, the idxFlags field 6896** was added for [version 3.9.0] ([dateof:3.9.0]). 6897** It may therefore only be used if 6898** sqlite3_libversion_number() returns a value greater than or equal to 6899** 3009000. 6900*/ 6901struct sqlite3_index_info { 6902 /* Inputs */ 6903 int nConstraint; /* Number of entries in aConstraint */ 6904 struct sqlite3_index_constraint { 6905 int iColumn; /* Column constrained. -1 for ROWID */ 6906 unsigned char op; /* Constraint operator */ 6907 unsigned char usable; /* True if this constraint is usable */ 6908 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6909 } *aConstraint; /* Table of WHERE clause constraints */ 6910 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6911 struct sqlite3_index_orderby { 6912 int iColumn; /* Column number */ 6913 unsigned char desc; /* True for DESC. False for ASC. */ 6914 } *aOrderBy; /* The ORDER BY clause */ 6915 /* Outputs */ 6916 struct sqlite3_index_constraint_usage { 6917 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6918 unsigned char omit; /* Do not code a test for this constraint */ 6919 } *aConstraintUsage; 6920 int idxNum; /* Number used to identify the index */ 6921 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6922 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6923 int orderByConsumed; /* True if output is already ordered */ 6924 double estimatedCost; /* Estimated cost of using this index */ 6925 /* Fields below are only available in SQLite 3.8.2 and later */ 6926 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6927 /* Fields below are only available in SQLite 3.9.0 and later */ 6928 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6929 /* Fields below are only available in SQLite 3.10.0 and later */ 6930 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6931}; 6932 6933/* 6934** CAPI3REF: Virtual Table Scan Flags 6935** 6936** Virtual table implementations are allowed to set the 6937** [sqlite3_index_info].idxFlags field to some combination of 6938** these bits. 6939*/ 6940#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6941 6942/* 6943** CAPI3REF: Virtual Table Constraint Operator Codes 6944** 6945** These macros define the allowed values for the 6946** [sqlite3_index_info].aConstraint[].op field. Each value represents 6947** an operator that is part of a constraint term in the wHERE clause of 6948** a query that uses a [virtual table]. 6949*/ 6950#define SQLITE_INDEX_CONSTRAINT_EQ 2 6951#define SQLITE_INDEX_CONSTRAINT_GT 4 6952#define SQLITE_INDEX_CONSTRAINT_LE 8 6953#define SQLITE_INDEX_CONSTRAINT_LT 16 6954#define SQLITE_INDEX_CONSTRAINT_GE 32 6955#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6956#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6957#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6958#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6959#define SQLITE_INDEX_CONSTRAINT_NE 68 6960#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6961#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6962#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6963#define SQLITE_INDEX_CONSTRAINT_IS 72 6964#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150 6965 6966/* 6967** CAPI3REF: Register A Virtual Table Implementation 6968** METHOD: sqlite3 6969** 6970** ^These routines are used to register a new [virtual table module] name. 6971** ^Module names must be registered before 6972** creating a new [virtual table] using the module and before using a 6973** preexisting [virtual table] for the module. 6974** 6975** ^The module name is registered on the [database connection] specified 6976** by the first parameter. ^The name of the module is given by the 6977** second parameter. ^The third parameter is a pointer to 6978** the implementation of the [virtual table module]. ^The fourth 6979** parameter is an arbitrary client data pointer that is passed through 6980** into the [xCreate] and [xConnect] methods of the virtual table module 6981** when a new virtual table is be being created or reinitialized. 6982** 6983** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6984** is a pointer to a destructor for the pClientData. ^SQLite will 6985** invoke the destructor function (if it is not NULL) when SQLite 6986** no longer needs the pClientData pointer. ^The destructor will also 6987** be invoked if the call to sqlite3_create_module_v2() fails. 6988** ^The sqlite3_create_module() 6989** interface is equivalent to sqlite3_create_module_v2() with a NULL 6990** destructor. 6991** 6992** ^If the third parameter (the pointer to the sqlite3_module object) is 6993** NULL then no new module is create and any existing modules with the 6994** same name are dropped. 6995** 6996** See also: [sqlite3_drop_modules()] 6997*/ 6998int sqlite3_create_module( 6999 sqlite3 *db, /* SQLite connection to register module with */ 7000 const char *zName, /* Name of the module */ 7001 const sqlite3_module *p, /* Methods for the module */ 7002 void *pClientData /* Client data for xCreate/xConnect */ 7003); 7004int sqlite3_create_module_v2( 7005 sqlite3 *db, /* SQLite connection to register module with */ 7006 const char *zName, /* Name of the module */ 7007 const sqlite3_module *p, /* Methods for the module */ 7008 void *pClientData, /* Client data for xCreate/xConnect */ 7009 void(*xDestroy)(void*) /* Module destructor function */ 7010); 7011 7012/* 7013** CAPI3REF: Remove Unnecessary Virtual Table Implementations 7014** METHOD: sqlite3 7015** 7016** ^The sqlite3_drop_modules(D,L) interface removes all virtual 7017** table modules from database connection D except those named on list L. 7018** The L parameter must be either NULL or a pointer to an array of pointers 7019** to strings where the array is terminated by a single NULL pointer. 7020** ^If the L parameter is NULL, then all virtual table modules are removed. 7021** 7022** See also: [sqlite3_create_module()] 7023*/ 7024int sqlite3_drop_modules( 7025 sqlite3 *db, /* Remove modules from this connection */ 7026 const char **azKeep /* Except, do not remove the ones named here */ 7027); 7028 7029/* 7030** CAPI3REF: Virtual Table Instance Object 7031** KEYWORDS: sqlite3_vtab 7032** 7033** Every [virtual table module] implementation uses a subclass 7034** of this object to describe a particular instance 7035** of the [virtual table]. Each subclass will 7036** be tailored to the specific needs of the module implementation. 7037** The purpose of this superclass is to define certain fields that are 7038** common to all module implementations. 7039** 7040** ^Virtual tables methods can set an error message by assigning a 7041** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 7042** take care that any prior string is freed by a call to [sqlite3_free()] 7043** prior to assigning a new string to zErrMsg. ^After the error message 7044** is delivered up to the client application, the string will be automatically 7045** freed by sqlite3_free() and the zErrMsg field will be zeroed. 7046*/ 7047struct sqlite3_vtab { 7048 const sqlite3_module *pModule; /* The module for this virtual table */ 7049 int nRef; /* Number of open cursors */ 7050 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 7051 /* Virtual table implementations will typically add additional fields */ 7052}; 7053 7054/* 7055** CAPI3REF: Virtual Table Cursor Object 7056** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 7057** 7058** Every [virtual table module] implementation uses a subclass of the 7059** following structure to describe cursors that point into the 7060** [virtual table] and are used 7061** to loop through the virtual table. Cursors are created using the 7062** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 7063** by the [sqlite3_module.xClose | xClose] method. Cursors are used 7064** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 7065** of the module. Each module implementation will define 7066** the content of a cursor structure to suit its own needs. 7067** 7068** This superclass exists in order to define fields of the cursor that 7069** are common to all implementations. 7070*/ 7071struct sqlite3_vtab_cursor { 7072 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 7073 /* Virtual table implementations will typically add additional fields */ 7074}; 7075 7076/* 7077** CAPI3REF: Declare The Schema Of A Virtual Table 7078** 7079** ^The [xCreate] and [xConnect] methods of a 7080** [virtual table module] call this interface 7081** to declare the format (the names and datatypes of the columns) of 7082** the virtual tables they implement. 7083*/ 7084int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 7085 7086/* 7087** CAPI3REF: Overload A Function For A Virtual Table 7088** METHOD: sqlite3 7089** 7090** ^(Virtual tables can provide alternative implementations of functions 7091** using the [xFindFunction] method of the [virtual table module]. 7092** But global versions of those functions 7093** must exist in order to be overloaded.)^ 7094** 7095** ^(This API makes sure a global version of a function with a particular 7096** name and number of parameters exists. If no such function exists 7097** before this API is called, a new function is created.)^ ^The implementation 7098** of the new function always causes an exception to be thrown. So 7099** the new function is not good for anything by itself. Its only 7100** purpose is to be a placeholder function that can be overloaded 7101** by a [virtual table]. 7102*/ 7103int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 7104 7105/* 7106** The interface to the virtual-table mechanism defined above (back up 7107** to a comment remarkably similar to this one) is currently considered 7108** to be experimental. The interface might change in incompatible ways. 7109** If this is a problem for you, do not use the interface at this time. 7110** 7111** When the virtual-table mechanism stabilizes, we will declare the 7112** interface fixed, support it indefinitely, and remove this comment. 7113*/ 7114 7115/* 7116** CAPI3REF: A Handle To An Open BLOB 7117** KEYWORDS: {BLOB handle} {BLOB handles} 7118** 7119** An instance of this object represents an open BLOB on which 7120** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 7121** ^Objects of this type are created by [sqlite3_blob_open()] 7122** and destroyed by [sqlite3_blob_close()]. 7123** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 7124** can be used to read or write small subsections of the BLOB. 7125** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 7126*/ 7127typedef struct sqlite3_blob sqlite3_blob; 7128 7129/* 7130** CAPI3REF: Open A BLOB For Incremental I/O 7131** METHOD: sqlite3 7132** CONSTRUCTOR: sqlite3_blob 7133** 7134** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 7135** in row iRow, column zColumn, table zTable in database zDb; 7136** in other words, the same BLOB that would be selected by: 7137** 7138** <pre> 7139** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 7140** </pre>)^ 7141** 7142** ^(Parameter zDb is not the filename that contains the database, but 7143** rather the symbolic name of the database. For attached databases, this is 7144** the name that appears after the AS keyword in the [ATTACH] statement. 7145** For the main database file, the database name is "main". For TEMP 7146** tables, the database name is "temp".)^ 7147** 7148** ^If the flags parameter is non-zero, then the BLOB is opened for read 7149** and write access. ^If the flags parameter is zero, the BLOB is opened for 7150** read-only access. 7151** 7152** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 7153** in *ppBlob. Otherwise an [error code] is returned and, unless the error 7154** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 7155** the API is not misused, it is always safe to call [sqlite3_blob_close()] 7156** on *ppBlob after this function it returns. 7157** 7158** This function fails with SQLITE_ERROR if any of the following are true: 7159** <ul> 7160** <li> ^(Database zDb does not exist)^, 7161** <li> ^(Table zTable does not exist within database zDb)^, 7162** <li> ^(Table zTable is a WITHOUT ROWID table)^, 7163** <li> ^(Column zColumn does not exist)^, 7164** <li> ^(Row iRow is not present in the table)^, 7165** <li> ^(The specified column of row iRow contains a value that is not 7166** a TEXT or BLOB value)^, 7167** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 7168** constraint and the blob is being opened for read/write access)^, 7169** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 7170** column zColumn is part of a [child key] definition and the blob is 7171** being opened for read/write access)^. 7172** </ul> 7173** 7174** ^Unless it returns SQLITE_MISUSE, this function sets the 7175** [database connection] error code and message accessible via 7176** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7177** 7178** A BLOB referenced by sqlite3_blob_open() may be read using the 7179** [sqlite3_blob_read()] interface and modified by using 7180** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 7181** different row of the same table using the [sqlite3_blob_reopen()] 7182** interface. However, the column, table, or database of a [BLOB handle] 7183** cannot be changed after the [BLOB handle] is opened. 7184** 7185** ^(If the row that a BLOB handle points to is modified by an 7186** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 7187** then the BLOB handle is marked as "expired". 7188** This is true if any column of the row is changed, even a column 7189** other than the one the BLOB handle is open on.)^ 7190** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 7191** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 7192** ^(Changes written into a BLOB prior to the BLOB expiring are not 7193** rolled back by the expiration of the BLOB. Such changes will eventually 7194** commit if the transaction continues to completion.)^ 7195** 7196** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 7197** the opened blob. ^The size of a blob may not be changed by this 7198** interface. Use the [UPDATE] SQL command to change the size of a 7199** blob. 7200** 7201** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 7202** and the built-in [zeroblob] SQL function may be used to create a 7203** zero-filled blob to read or write using the incremental-blob interface. 7204** 7205** To avoid a resource leak, every open [BLOB handle] should eventually 7206** be released by a call to [sqlite3_blob_close()]. 7207** 7208** See also: [sqlite3_blob_close()], 7209** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 7210** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 7211*/ 7212int sqlite3_blob_open( 7213 sqlite3*, 7214 const char *zDb, 7215 const char *zTable, 7216 const char *zColumn, 7217 sqlite3_int64 iRow, 7218 int flags, 7219 sqlite3_blob **ppBlob 7220); 7221 7222/* 7223** CAPI3REF: Move a BLOB Handle to a New Row 7224** METHOD: sqlite3_blob 7225** 7226** ^This function is used to move an existing [BLOB handle] so that it points 7227** to a different row of the same database table. ^The new row is identified 7228** by the rowid value passed as the second argument. Only the row can be 7229** changed. ^The database, table and column on which the blob handle is open 7230** remain the same. Moving an existing [BLOB handle] to a new row is 7231** faster than closing the existing handle and opening a new one. 7232** 7233** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 7234** it must exist and there must be either a blob or text value stored in 7235** the nominated column.)^ ^If the new row is not present in the table, or if 7236** it does not contain a blob or text value, or if another error occurs, an 7237** SQLite error code is returned and the blob handle is considered aborted. 7238** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 7239** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 7240** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 7241** always returns zero. 7242** 7243** ^This function sets the database handle error code and message. 7244*/ 7245int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 7246 7247/* 7248** CAPI3REF: Close A BLOB Handle 7249** DESTRUCTOR: sqlite3_blob 7250** 7251** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 7252** unconditionally. Even if this routine returns an error code, the 7253** handle is still closed.)^ 7254** 7255** ^If the blob handle being closed was opened for read-write access, and if 7256** the database is in auto-commit mode and there are no other open read-write 7257** blob handles or active write statements, the current transaction is 7258** committed. ^If an error occurs while committing the transaction, an error 7259** code is returned and the transaction rolled back. 7260** 7261** Calling this function with an argument that is not a NULL pointer or an 7262** open blob handle results in undefined behaviour. ^Calling this routine 7263** with a null pointer (such as would be returned by a failed call to 7264** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 7265** is passed a valid open blob handle, the values returned by the 7266** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 7267*/ 7268int sqlite3_blob_close(sqlite3_blob *); 7269 7270/* 7271** CAPI3REF: Return The Size Of An Open BLOB 7272** METHOD: sqlite3_blob 7273** 7274** ^Returns the size in bytes of the BLOB accessible via the 7275** successfully opened [BLOB handle] in its only argument. ^The 7276** incremental blob I/O routines can only read or overwriting existing 7277** blob content; they cannot change the size of a blob. 7278** 7279** This routine only works on a [BLOB handle] which has been created 7280** by a prior successful call to [sqlite3_blob_open()] and which has not 7281** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7282** to this routine results in undefined and probably undesirable behavior. 7283*/ 7284int sqlite3_blob_bytes(sqlite3_blob *); 7285 7286/* 7287** CAPI3REF: Read Data From A BLOB Incrementally 7288** METHOD: sqlite3_blob 7289** 7290** ^(This function is used to read data from an open [BLOB handle] into a 7291** caller-supplied buffer. N bytes of data are copied into buffer Z 7292** from the open BLOB, starting at offset iOffset.)^ 7293** 7294** ^If offset iOffset is less than N bytes from the end of the BLOB, 7295** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 7296** less than zero, [SQLITE_ERROR] is returned and no data is read. 7297** ^The size of the blob (and hence the maximum value of N+iOffset) 7298** can be determined using the [sqlite3_blob_bytes()] interface. 7299** 7300** ^An attempt to read from an expired [BLOB handle] fails with an 7301** error code of [SQLITE_ABORT]. 7302** 7303** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 7304** Otherwise, an [error code] or an [extended error code] is returned.)^ 7305** 7306** This routine only works on a [BLOB handle] which has been created 7307** by a prior successful call to [sqlite3_blob_open()] and which has not 7308** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7309** to this routine results in undefined and probably undesirable behavior. 7310** 7311** See also: [sqlite3_blob_write()]. 7312*/ 7313int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 7314 7315/* 7316** CAPI3REF: Write Data Into A BLOB Incrementally 7317** METHOD: sqlite3_blob 7318** 7319** ^(This function is used to write data into an open [BLOB handle] from a 7320** caller-supplied buffer. N bytes of data are copied from the buffer Z 7321** into the open BLOB, starting at offset iOffset.)^ 7322** 7323** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 7324** Otherwise, an [error code] or an [extended error code] is returned.)^ 7325** ^Unless SQLITE_MISUSE is returned, this function sets the 7326** [database connection] error code and message accessible via 7327** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7328** 7329** ^If the [BLOB handle] passed as the first argument was not opened for 7330** writing (the flags parameter to [sqlite3_blob_open()] was zero), 7331** this function returns [SQLITE_READONLY]. 7332** 7333** This function may only modify the contents of the BLOB; it is 7334** not possible to increase the size of a BLOB using this API. 7335** ^If offset iOffset is less than N bytes from the end of the BLOB, 7336** [SQLITE_ERROR] is returned and no data is written. The size of the 7337** BLOB (and hence the maximum value of N+iOffset) can be determined 7338** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 7339** than zero [SQLITE_ERROR] is returned and no data is written. 7340** 7341** ^An attempt to write to an expired [BLOB handle] fails with an 7342** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 7343** before the [BLOB handle] expired are not rolled back by the 7344** expiration of the handle, though of course those changes might 7345** have been overwritten by the statement that expired the BLOB handle 7346** or by other independent statements. 7347** 7348** This routine only works on a [BLOB handle] which has been created 7349** by a prior successful call to [sqlite3_blob_open()] and which has not 7350** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7351** to this routine results in undefined and probably undesirable behavior. 7352** 7353** See also: [sqlite3_blob_read()]. 7354*/ 7355int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 7356 7357/* 7358** CAPI3REF: Virtual File System Objects 7359** 7360** A virtual filesystem (VFS) is an [sqlite3_vfs] object 7361** that SQLite uses to interact 7362** with the underlying operating system. Most SQLite builds come with a 7363** single default VFS that is appropriate for the host computer. 7364** New VFSes can be registered and existing VFSes can be unregistered. 7365** The following interfaces are provided. 7366** 7367** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 7368** ^Names are case sensitive. 7369** ^Names are zero-terminated UTF-8 strings. 7370** ^If there is no match, a NULL pointer is returned. 7371** ^If zVfsName is NULL then the default VFS is returned. 7372** 7373** ^New VFSes are registered with sqlite3_vfs_register(). 7374** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 7375** ^The same VFS can be registered multiple times without injury. 7376** ^To make an existing VFS into the default VFS, register it again 7377** with the makeDflt flag set. If two different VFSes with the 7378** same name are registered, the behavior is undefined. If a 7379** VFS is registered with a name that is NULL or an empty string, 7380** then the behavior is undefined. 7381** 7382** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 7383** ^(If the default VFS is unregistered, another VFS is chosen as 7384** the default. The choice for the new VFS is arbitrary.)^ 7385*/ 7386sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 7387int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 7388int sqlite3_vfs_unregister(sqlite3_vfs*); 7389 7390/* 7391** CAPI3REF: Mutexes 7392** 7393** The SQLite core uses these routines for thread 7394** synchronization. Though they are intended for internal 7395** use by SQLite, code that links against SQLite is 7396** permitted to use any of these routines. 7397** 7398** The SQLite source code contains multiple implementations 7399** of these mutex routines. An appropriate implementation 7400** is selected automatically at compile-time. The following 7401** implementations are available in the SQLite core: 7402** 7403** <ul> 7404** <li> SQLITE_MUTEX_PTHREADS 7405** <li> SQLITE_MUTEX_W32 7406** <li> SQLITE_MUTEX_NOOP 7407** </ul> 7408** 7409** The SQLITE_MUTEX_NOOP implementation is a set of routines 7410** that does no real locking and is appropriate for use in 7411** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 7412** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 7413** and Windows. 7414** 7415** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 7416** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 7417** implementation is included with the library. In this case the 7418** application must supply a custom mutex implementation using the 7419** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 7420** before calling sqlite3_initialize() or any other public sqlite3_ 7421** function that calls sqlite3_initialize(). 7422** 7423** ^The sqlite3_mutex_alloc() routine allocates a new 7424** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 7425** routine returns NULL if it is unable to allocate the requested 7426** mutex. The argument to sqlite3_mutex_alloc() must one of these 7427** integer constants: 7428** 7429** <ul> 7430** <li> SQLITE_MUTEX_FAST 7431** <li> SQLITE_MUTEX_RECURSIVE 7432** <li> SQLITE_MUTEX_STATIC_MAIN 7433** <li> SQLITE_MUTEX_STATIC_MEM 7434** <li> SQLITE_MUTEX_STATIC_OPEN 7435** <li> SQLITE_MUTEX_STATIC_PRNG 7436** <li> SQLITE_MUTEX_STATIC_LRU 7437** <li> SQLITE_MUTEX_STATIC_PMEM 7438** <li> SQLITE_MUTEX_STATIC_APP1 7439** <li> SQLITE_MUTEX_STATIC_APP2 7440** <li> SQLITE_MUTEX_STATIC_APP3 7441** <li> SQLITE_MUTEX_STATIC_VFS1 7442** <li> SQLITE_MUTEX_STATIC_VFS2 7443** <li> SQLITE_MUTEX_STATIC_VFS3 7444** </ul> 7445** 7446** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 7447** cause sqlite3_mutex_alloc() to create 7448** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 7449** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 7450** The mutex implementation does not need to make a distinction 7451** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 7452** not want to. SQLite will only request a recursive mutex in 7453** cases where it really needs one. If a faster non-recursive mutex 7454** implementation is available on the host platform, the mutex subsystem 7455** might return such a mutex in response to SQLITE_MUTEX_FAST. 7456** 7457** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 7458** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 7459** a pointer to a static preexisting mutex. ^Nine static mutexes are 7460** used by the current version of SQLite. Future versions of SQLite 7461** may add additional static mutexes. Static mutexes are for internal 7462** use by SQLite only. Applications that use SQLite mutexes should 7463** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 7464** SQLITE_MUTEX_RECURSIVE. 7465** 7466** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 7467** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 7468** returns a different mutex on every call. ^For the static 7469** mutex types, the same mutex is returned on every call that has 7470** the same type number. 7471** 7472** ^The sqlite3_mutex_free() routine deallocates a previously 7473** allocated dynamic mutex. Attempting to deallocate a static 7474** mutex results in undefined behavior. 7475** 7476** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 7477** to enter a mutex. ^If another thread is already within the mutex, 7478** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 7479** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 7480** upon successful entry. ^(Mutexes created using 7481** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 7482** In such cases, the 7483** mutex must be exited an equal number of times before another thread 7484** can enter.)^ If the same thread tries to enter any mutex other 7485** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 7486** 7487** ^(Some systems (for example, Windows 95) do not support the operation 7488** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 7489** will always return SQLITE_BUSY. The SQLite core only ever uses 7490** sqlite3_mutex_try() as an optimization so this is acceptable 7491** behavior.)^ 7492** 7493** ^The sqlite3_mutex_leave() routine exits a mutex that was 7494** previously entered by the same thread. The behavior 7495** is undefined if the mutex is not currently entered by the 7496** calling thread or is not currently allocated. 7497** 7498** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 7499** sqlite3_mutex_leave() is a NULL pointer, then all three routines 7500** behave as no-ops. 7501** 7502** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 7503*/ 7504sqlite3_mutex *sqlite3_mutex_alloc(int); 7505void sqlite3_mutex_free(sqlite3_mutex*); 7506void sqlite3_mutex_enter(sqlite3_mutex*); 7507int sqlite3_mutex_try(sqlite3_mutex*); 7508void sqlite3_mutex_leave(sqlite3_mutex*); 7509 7510/* 7511** CAPI3REF: Mutex Methods Object 7512** 7513** An instance of this structure defines the low-level routines 7514** used to allocate and use mutexes. 7515** 7516** Usually, the default mutex implementations provided by SQLite are 7517** sufficient, however the application has the option of substituting a custom 7518** implementation for specialized deployments or systems for which SQLite 7519** does not provide a suitable implementation. In this case, the application 7520** creates and populates an instance of this structure to pass 7521** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 7522** Additionally, an instance of this structure can be used as an 7523** output variable when querying the system for the current mutex 7524** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 7525** 7526** ^The xMutexInit method defined by this structure is invoked as 7527** part of system initialization by the sqlite3_initialize() function. 7528** ^The xMutexInit routine is called by SQLite exactly once for each 7529** effective call to [sqlite3_initialize()]. 7530** 7531** ^The xMutexEnd method defined by this structure is invoked as 7532** part of system shutdown by the sqlite3_shutdown() function. The 7533** implementation of this method is expected to release all outstanding 7534** resources obtained by the mutex methods implementation, especially 7535** those obtained by the xMutexInit method. ^The xMutexEnd() 7536** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 7537** 7538** ^(The remaining seven methods defined by this structure (xMutexAlloc, 7539** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 7540** xMutexNotheld) implement the following interfaces (respectively): 7541** 7542** <ul> 7543** <li> [sqlite3_mutex_alloc()] </li> 7544** <li> [sqlite3_mutex_free()] </li> 7545** <li> [sqlite3_mutex_enter()] </li> 7546** <li> [sqlite3_mutex_try()] </li> 7547** <li> [sqlite3_mutex_leave()] </li> 7548** <li> [sqlite3_mutex_held()] </li> 7549** <li> [sqlite3_mutex_notheld()] </li> 7550** </ul>)^ 7551** 7552** The only difference is that the public sqlite3_XXX functions enumerated 7553** above silently ignore any invocations that pass a NULL pointer instead 7554** of a valid mutex handle. The implementations of the methods defined 7555** by this structure are not required to handle this case. The results 7556** of passing a NULL pointer instead of a valid mutex handle are undefined 7557** (i.e. it is acceptable to provide an implementation that segfaults if 7558** it is passed a NULL pointer). 7559** 7560** The xMutexInit() method must be threadsafe. It must be harmless to 7561** invoke xMutexInit() multiple times within the same process and without 7562** intervening calls to xMutexEnd(). Second and subsequent calls to 7563** xMutexInit() must be no-ops. 7564** 7565** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 7566** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 7567** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 7568** memory allocation for a fast or recursive mutex. 7569** 7570** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 7571** called, but only if the prior call to xMutexInit returned SQLITE_OK. 7572** If xMutexInit fails in any way, it is expected to clean up after itself 7573** prior to returning. 7574*/ 7575typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 7576struct sqlite3_mutex_methods { 7577 int (*xMutexInit)(void); 7578 int (*xMutexEnd)(void); 7579 sqlite3_mutex *(*xMutexAlloc)(int); 7580 void (*xMutexFree)(sqlite3_mutex *); 7581 void (*xMutexEnter)(sqlite3_mutex *); 7582 int (*xMutexTry)(sqlite3_mutex *); 7583 void (*xMutexLeave)(sqlite3_mutex *); 7584 int (*xMutexHeld)(sqlite3_mutex *); 7585 int (*xMutexNotheld)(sqlite3_mutex *); 7586}; 7587 7588/* 7589** CAPI3REF: Mutex Verification Routines 7590** 7591** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 7592** are intended for use inside assert() statements. The SQLite core 7593** never uses these routines except inside an assert() and applications 7594** are advised to follow the lead of the core. The SQLite core only 7595** provides implementations for these routines when it is compiled 7596** with the SQLITE_DEBUG flag. External mutex implementations 7597** are only required to provide these routines if SQLITE_DEBUG is 7598** defined and if NDEBUG is not defined. 7599** 7600** These routines should return true if the mutex in their argument 7601** is held or not held, respectively, by the calling thread. 7602** 7603** The implementation is not required to provide versions of these 7604** routines that actually work. If the implementation does not provide working 7605** versions of these routines, it should at least provide stubs that always 7606** return true so that one does not get spurious assertion failures. 7607** 7608** If the argument to sqlite3_mutex_held() is a NULL pointer then 7609** the routine should return 1. This seems counter-intuitive since 7610** clearly the mutex cannot be held if it does not exist. But 7611** the reason the mutex does not exist is because the build is not 7612** using mutexes. And we do not want the assert() containing the 7613** call to sqlite3_mutex_held() to fail, so a non-zero return is 7614** the appropriate thing to do. The sqlite3_mutex_notheld() 7615** interface should also return 1 when given a NULL pointer. 7616*/ 7617#ifndef NDEBUG 7618int sqlite3_mutex_held(sqlite3_mutex*); 7619int sqlite3_mutex_notheld(sqlite3_mutex*); 7620#endif 7621 7622/* 7623** CAPI3REF: Mutex Types 7624** 7625** The [sqlite3_mutex_alloc()] interface takes a single argument 7626** which is one of these integer constants. 7627** 7628** The set of static mutexes may change from one SQLite release to the 7629** next. Applications that override the built-in mutex logic must be 7630** prepared to accommodate additional static mutexes. 7631*/ 7632#define SQLITE_MUTEX_FAST 0 7633#define SQLITE_MUTEX_RECURSIVE 1 7634#define SQLITE_MUTEX_STATIC_MAIN 2 7635#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 7636#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 7637#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 7638#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 7639#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 7640#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 7641#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 7642#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 7643#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 7644#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 7645#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 7646#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 7647#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 7648 7649/* Legacy compatibility: */ 7650#define SQLITE_MUTEX_STATIC_MASTER 2 7651 7652 7653/* 7654** CAPI3REF: Retrieve the mutex for a database connection 7655** METHOD: sqlite3 7656** 7657** ^This interface returns a pointer the [sqlite3_mutex] object that 7658** serializes access to the [database connection] given in the argument 7659** when the [threading mode] is Serialized. 7660** ^If the [threading mode] is Single-thread or Multi-thread then this 7661** routine returns a NULL pointer. 7662*/ 7663sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 7664 7665/* 7666** CAPI3REF: Low-Level Control Of Database Files 7667** METHOD: sqlite3 7668** KEYWORDS: {file control} 7669** 7670** ^The [sqlite3_file_control()] interface makes a direct call to the 7671** xFileControl method for the [sqlite3_io_methods] object associated 7672** with a particular database identified by the second argument. ^The 7673** name of the database is "main" for the main database or "temp" for the 7674** TEMP database, or the name that appears after the AS keyword for 7675** databases that are added using the [ATTACH] SQL command. 7676** ^A NULL pointer can be used in place of "main" to refer to the 7677** main database file. 7678** ^The third and fourth parameters to this routine 7679** are passed directly through to the second and third parameters of 7680** the xFileControl method. ^The return value of the xFileControl 7681** method becomes the return value of this routine. 7682** 7683** A few opcodes for [sqlite3_file_control()] are handled directly 7684** by the SQLite core and never invoke the 7685** sqlite3_io_methods.xFileControl method. 7686** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 7687** a pointer to the underlying [sqlite3_file] object to be written into 7688** the space pointed to by the 4th parameter. The 7689** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns 7690** the [sqlite3_file] object associated with the journal file instead of 7691** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns 7692** a pointer to the underlying [sqlite3_vfs] object for the file. 7693** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter 7694** from the pager. 7695** 7696** ^If the second parameter (zDbName) does not match the name of any 7697** open database file, then SQLITE_ERROR is returned. ^This error 7698** code is not remembered and will not be recalled by [sqlite3_errcode()] 7699** or [sqlite3_errmsg()]. The underlying xFileControl method might 7700** also return SQLITE_ERROR. There is no way to distinguish between 7701** an incorrect zDbName and an SQLITE_ERROR return from the underlying 7702** xFileControl method. 7703** 7704** See also: [file control opcodes] 7705*/ 7706int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 7707 7708/* 7709** CAPI3REF: Testing Interface 7710** 7711** ^The sqlite3_test_control() interface is used to read out internal 7712** state of SQLite and to inject faults into SQLite for testing 7713** purposes. ^The first parameter is an operation code that determines 7714** the number, meaning, and operation of all subsequent parameters. 7715** 7716** This interface is not for use by applications. It exists solely 7717** for verifying the correct operation of the SQLite library. Depending 7718** on how the SQLite library is compiled, this interface might not exist. 7719** 7720** The details of the operation codes, their meanings, the parameters 7721** they take, and what they do are all subject to change without notice. 7722** Unlike most of the SQLite API, this function is not guaranteed to 7723** operate consistently from one release to the next. 7724*/ 7725int sqlite3_test_control(int op, ...); 7726 7727/* 7728** CAPI3REF: Testing Interface Operation Codes 7729** 7730** These constants are the valid operation code parameters used 7731** as the first argument to [sqlite3_test_control()]. 7732** 7733** These parameters and their meanings are subject to change 7734** without notice. These values are for testing purposes only. 7735** Applications should not use any of these parameters or the 7736** [sqlite3_test_control()] interface. 7737*/ 7738#define SQLITE_TESTCTRL_FIRST 5 7739#define SQLITE_TESTCTRL_PRNG_SAVE 5 7740#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7741#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */ 7742#define SQLITE_TESTCTRL_SEEK_COUNT 7 7743#define SQLITE_TESTCTRL_BITVEC_TEST 8 7744#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7745#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7746#define SQLITE_TESTCTRL_PENDING_BYTE 11 7747#define SQLITE_TESTCTRL_ASSERT 12 7748#define SQLITE_TESTCTRL_ALWAYS 13 7749#define SQLITE_TESTCTRL_RESERVE 14 /* NOT USED */ 7750#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7751#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */ 7752#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7753#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17 7754#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7755#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7756#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7757#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7758#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7759#define SQLITE_TESTCTRL_BYTEORDER 22 7760#define SQLITE_TESTCTRL_ISINIT 23 7761#define SQLITE_TESTCTRL_SORTER_MMAP 24 7762#define SQLITE_TESTCTRL_IMPOSTER 25 7763#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7764#define SQLITE_TESTCTRL_RESULT_INTREAL 27 7765#define SQLITE_TESTCTRL_PRNG_SEED 28 7766#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29 7767#define SQLITE_TESTCTRL_LAST 29 /* Largest TESTCTRL */ 7768 7769/* 7770** CAPI3REF: SQL Keyword Checking 7771** 7772** These routines provide access to the set of SQL language keywords 7773** recognized by SQLite. Applications can uses these routines to determine 7774** whether or not a specific identifier needs to be escaped (for example, 7775** by enclosing in double-quotes) so as not to confuse the parser. 7776** 7777** The sqlite3_keyword_count() interface returns the number of distinct 7778** keywords understood by SQLite. 7779** 7780** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and 7781** makes *Z point to that keyword expressed as UTF8 and writes the number 7782** of bytes in the keyword into *L. The string that *Z points to is not 7783** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns 7784** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z 7785** or L are NULL or invalid pointers then calls to 7786** sqlite3_keyword_name(N,Z,L) result in undefined behavior. 7787** 7788** The sqlite3_keyword_check(Z,L) interface checks to see whether or not 7789** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero 7790** if it is and zero if not. 7791** 7792** The parser used by SQLite is forgiving. It is often possible to use 7793** a keyword as an identifier as long as such use does not result in a 7794** parsing ambiguity. For example, the statement 7795** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and 7796** creates a new table named "BEGIN" with three columns named 7797** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid 7798** using keywords as identifiers. Common techniques used to avoid keyword 7799** name collisions include: 7800** <ul> 7801** <li> Put all identifier names inside double-quotes. This is the official 7802** SQL way to escape identifier names. 7803** <li> Put identifier names inside [...]. This is not standard SQL, 7804** but it is what SQL Server does and so lots of programmers use this 7805** technique. 7806** <li> Begin every identifier with the letter "Z" as no SQL keywords start 7807** with "Z". 7808** <li> Include a digit somewhere in every identifier name. 7809** </ul> 7810** 7811** Note that the number of keywords understood by SQLite can depend on 7812** compile-time options. For example, "VACUUM" is not a keyword if 7813** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also, 7814** new keywords may be added to future releases of SQLite. 7815*/ 7816int sqlite3_keyword_count(void); 7817int sqlite3_keyword_name(int,const char**,int*); 7818int sqlite3_keyword_check(const char*,int); 7819 7820/* 7821** CAPI3REF: Dynamic String Object 7822** KEYWORDS: {dynamic string} 7823** 7824** An instance of the sqlite3_str object contains a dynamically-sized 7825** string under construction. 7826** 7827** The lifecycle of an sqlite3_str object is as follows: 7828** <ol> 7829** <li> ^The sqlite3_str object is created using [sqlite3_str_new()]. 7830** <li> ^Text is appended to the sqlite3_str object using various 7831** methods, such as [sqlite3_str_appendf()]. 7832** <li> ^The sqlite3_str object is destroyed and the string it created 7833** is returned using the [sqlite3_str_finish()] interface. 7834** </ol> 7835*/ 7836typedef struct sqlite3_str sqlite3_str; 7837 7838/* 7839** CAPI3REF: Create A New Dynamic String Object 7840** CONSTRUCTOR: sqlite3_str 7841** 7842** ^The [sqlite3_str_new(D)] interface allocates and initializes 7843** a new [sqlite3_str] object. To avoid memory leaks, the object returned by 7844** [sqlite3_str_new()] must be freed by a subsequent call to 7845** [sqlite3_str_finish(X)]. 7846** 7847** ^The [sqlite3_str_new(D)] interface always returns a pointer to a 7848** valid [sqlite3_str] object, though in the event of an out-of-memory 7849** error the returned object might be a special singleton that will 7850** silently reject new text, always return SQLITE_NOMEM from 7851** [sqlite3_str_errcode()], always return 0 for 7852** [sqlite3_str_length()], and always return NULL from 7853** [sqlite3_str_finish(X)]. It is always safe to use the value 7854** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter 7855** to any of the other [sqlite3_str] methods. 7856** 7857** The D parameter to [sqlite3_str_new(D)] may be NULL. If the 7858** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum 7859** length of the string contained in the [sqlite3_str] object will be 7860** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead 7861** of [SQLITE_MAX_LENGTH]. 7862*/ 7863sqlite3_str *sqlite3_str_new(sqlite3*); 7864 7865/* 7866** CAPI3REF: Finalize A Dynamic String 7867** DESTRUCTOR: sqlite3_str 7868** 7869** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X 7870** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()] 7871** that contains the constructed string. The calling application should 7872** pass the returned value to [sqlite3_free()] to avoid a memory leak. 7873** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any 7874** errors were encountered during construction of the string. ^The 7875** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the 7876** string in [sqlite3_str] object X is zero bytes long. 7877*/ 7878char *sqlite3_str_finish(sqlite3_str*); 7879 7880/* 7881** CAPI3REF: Add Content To A Dynamic String 7882** METHOD: sqlite3_str 7883** 7884** These interfaces add content to an sqlite3_str object previously obtained 7885** from [sqlite3_str_new()]. 7886** 7887** ^The [sqlite3_str_appendf(X,F,...)] and 7888** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf] 7889** functionality of SQLite to append formatted text onto the end of 7890** [sqlite3_str] object X. 7891** 7892** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S 7893** onto the end of the [sqlite3_str] object X. N must be non-negative. 7894** S must contain at least N non-zero bytes of content. To append a 7895** zero-terminated string in its entirety, use the [sqlite3_str_appendall()] 7896** method instead. 7897** 7898** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of 7899** zero-terminated string S onto the end of [sqlite3_str] object X. 7900** 7901** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the 7902** single-byte character C onto the end of [sqlite3_str] object X. 7903** ^This method can be used, for example, to add whitespace indentation. 7904** 7905** ^The [sqlite3_str_reset(X)] method resets the string under construction 7906** inside [sqlite3_str] object X back to zero bytes in length. 7907** 7908** These methods do not return a result code. ^If an error occurs, that fact 7909** is recorded in the [sqlite3_str] object and can be recovered by a 7910** subsequent call to [sqlite3_str_errcode(X)]. 7911*/ 7912void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...); 7913void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list); 7914void sqlite3_str_append(sqlite3_str*, const char *zIn, int N); 7915void sqlite3_str_appendall(sqlite3_str*, const char *zIn); 7916void sqlite3_str_appendchar(sqlite3_str*, int N, char C); 7917void sqlite3_str_reset(sqlite3_str*); 7918 7919/* 7920** CAPI3REF: Status Of A Dynamic String 7921** METHOD: sqlite3_str 7922** 7923** These interfaces return the current status of an [sqlite3_str] object. 7924** 7925** ^If any prior errors have occurred while constructing the dynamic string 7926** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return 7927** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns 7928** [SQLITE_NOMEM] following any out-of-memory error, or 7929** [SQLITE_TOOBIG] if the size of the dynamic string exceeds 7930** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors. 7931** 7932** ^The [sqlite3_str_length(X)] method returns the current length, in bytes, 7933** of the dynamic string under construction in [sqlite3_str] object X. 7934** ^The length returned by [sqlite3_str_length(X)] does not include the 7935** zero-termination byte. 7936** 7937** ^The [sqlite3_str_value(X)] method returns a pointer to the current 7938** content of the dynamic string under construction in X. The value 7939** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X 7940** and might be freed or altered by any subsequent method on the same 7941** [sqlite3_str] object. Applications must not used the pointer returned 7942** [sqlite3_str_value(X)] after any subsequent method call on the same 7943** object. ^Applications may change the content of the string returned 7944** by [sqlite3_str_value(X)] as long as they do not write into any bytes 7945** outside the range of 0 to [sqlite3_str_length(X)] and do not read or 7946** write any byte after any subsequent sqlite3_str method call. 7947*/ 7948int sqlite3_str_errcode(sqlite3_str*); 7949int sqlite3_str_length(sqlite3_str*); 7950char *sqlite3_str_value(sqlite3_str*); 7951 7952/* 7953** CAPI3REF: SQLite Runtime Status 7954** 7955** ^These interfaces are used to retrieve runtime status information 7956** about the performance of SQLite, and optionally to reset various 7957** highwater marks. ^The first argument is an integer code for 7958** the specific parameter to measure. ^(Recognized integer codes 7959** are of the form [status parameters | SQLITE_STATUS_...].)^ 7960** ^The current value of the parameter is returned into *pCurrent. 7961** ^The highest recorded value is returned in *pHighwater. ^If the 7962** resetFlag is true, then the highest record value is reset after 7963** *pHighwater is written. ^(Some parameters do not record the highest 7964** value. For those parameters 7965** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7966** ^(Other parameters record only the highwater mark and not the current 7967** value. For these latter parameters nothing is written into *pCurrent.)^ 7968** 7969** ^The sqlite3_status() and sqlite3_status64() routines return 7970** SQLITE_OK on success and a non-zero [error code] on failure. 7971** 7972** If either the current value or the highwater mark is too large to 7973** be represented by a 32-bit integer, then the values returned by 7974** sqlite3_status() are undefined. 7975** 7976** See also: [sqlite3_db_status()] 7977*/ 7978int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7979int sqlite3_status64( 7980 int op, 7981 sqlite3_int64 *pCurrent, 7982 sqlite3_int64 *pHighwater, 7983 int resetFlag 7984); 7985 7986 7987/* 7988** CAPI3REF: Status Parameters 7989** KEYWORDS: {status parameters} 7990** 7991** These integer constants designate various run-time status parameters 7992** that can be returned by [sqlite3_status()]. 7993** 7994** <dl> 7995** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7996** <dd>This parameter is the current amount of memory checked out 7997** using [sqlite3_malloc()], either directly or indirectly. The 7998** figure includes calls made to [sqlite3_malloc()] by the application 7999** and internal memory usage by the SQLite library. Auxiliary page-cache 8000** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 8001** this parameter. The amount returned is the sum of the allocation 8002** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 8003** 8004** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 8005** <dd>This parameter records the largest memory allocation request 8006** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 8007** internal equivalents). Only the value returned in the 8008** *pHighwater parameter to [sqlite3_status()] is of interest. 8009** The value written into the *pCurrent parameter is undefined.</dd>)^ 8010** 8011** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 8012** <dd>This parameter records the number of separate memory allocations 8013** currently checked out.</dd>)^ 8014** 8015** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 8016** <dd>This parameter returns the number of pages used out of the 8017** [pagecache memory allocator] that was configured using 8018** [SQLITE_CONFIG_PAGECACHE]. The 8019** value returned is in pages, not in bytes.</dd>)^ 8020** 8021** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 8022** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 8023** <dd>This parameter returns the number of bytes of page cache 8024** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 8025** buffer and where forced to overflow to [sqlite3_malloc()]. The 8026** returned value includes allocations that overflowed because they 8027** where too large (they were larger than the "sz" parameter to 8028** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 8029** no space was left in the page cache.</dd>)^ 8030** 8031** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 8032** <dd>This parameter records the largest memory allocation request 8033** handed to the [pagecache memory allocator]. Only the value returned in the 8034** *pHighwater parameter to [sqlite3_status()] is of interest. 8035** The value written into the *pCurrent parameter is undefined.</dd>)^ 8036** 8037** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 8038** <dd>No longer used.</dd> 8039** 8040** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 8041** <dd>No longer used.</dd> 8042** 8043** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 8044** <dd>No longer used.</dd> 8045** 8046** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 8047** <dd>The *pHighwater parameter records the deepest parser stack. 8048** The *pCurrent value is undefined. The *pHighwater value is only 8049** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 8050** </dl> 8051** 8052** New status parameters may be added from time to time. 8053*/ 8054#define SQLITE_STATUS_MEMORY_USED 0 8055#define SQLITE_STATUS_PAGECACHE_USED 1 8056#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 8057#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 8058#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 8059#define SQLITE_STATUS_MALLOC_SIZE 5 8060#define SQLITE_STATUS_PARSER_STACK 6 8061#define SQLITE_STATUS_PAGECACHE_SIZE 7 8062#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 8063#define SQLITE_STATUS_MALLOC_COUNT 9 8064 8065/* 8066** CAPI3REF: Database Connection Status 8067** METHOD: sqlite3 8068** 8069** ^This interface is used to retrieve runtime status information 8070** about a single [database connection]. ^The first argument is the 8071** database connection object to be interrogated. ^The second argument 8072** is an integer constant, taken from the set of 8073** [SQLITE_DBSTATUS options], that 8074** determines the parameter to interrogate. The set of 8075** [SQLITE_DBSTATUS options] is likely 8076** to grow in future releases of SQLite. 8077** 8078** ^The current value of the requested parameter is written into *pCur 8079** and the highest instantaneous value is written into *pHiwtr. ^If 8080** the resetFlg is true, then the highest instantaneous value is 8081** reset back down to the current value. 8082** 8083** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 8084** non-zero [error code] on failure. 8085** 8086** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 8087*/ 8088int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 8089 8090/* 8091** CAPI3REF: Status Parameters for database connections 8092** KEYWORDS: {SQLITE_DBSTATUS options} 8093** 8094** These constants are the available integer "verbs" that can be passed as 8095** the second argument to the [sqlite3_db_status()] interface. 8096** 8097** New verbs may be added in future releases of SQLite. Existing verbs 8098** might be discontinued. Applications should check the return code from 8099** [sqlite3_db_status()] to make sure that the call worked. 8100** The [sqlite3_db_status()] interface will return a non-zero error code 8101** if a discontinued or unsupported verb is invoked. 8102** 8103** <dl> 8104** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 8105** <dd>This parameter returns the number of lookaside memory slots currently 8106** checked out.</dd>)^ 8107** 8108** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 8109** <dd>This parameter returns the number of malloc attempts that were 8110** satisfied using lookaside memory. Only the high-water value is meaningful; 8111** the current value is always zero.)^ 8112** 8113** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 8114** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 8115** <dd>This parameter returns the number malloc attempts that might have 8116** been satisfied using lookaside memory but failed due to the amount of 8117** memory requested being larger than the lookaside slot size. 8118** Only the high-water value is meaningful; 8119** the current value is always zero.)^ 8120** 8121** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 8122** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 8123** <dd>This parameter returns the number malloc attempts that might have 8124** been satisfied using lookaside memory but failed due to all lookaside 8125** memory already being in use. 8126** Only the high-water value is meaningful; 8127** the current value is always zero.)^ 8128** 8129** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 8130** <dd>This parameter returns the approximate number of bytes of heap 8131** memory used by all pager caches associated with the database connection.)^ 8132** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 8133** 8134** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 8135** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 8136** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 8137** pager cache is shared between two or more connections the bytes of heap 8138** memory used by that pager cache is divided evenly between the attached 8139** connections.)^ In other words, if none of the pager caches associated 8140** with the database connection are shared, this request returns the same 8141** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 8142** shared, the value returned by this call will be smaller than that returned 8143** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 8144** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 8145** 8146** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 8147** <dd>This parameter returns the approximate number of bytes of heap 8148** memory used to store the schema for all databases associated 8149** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 8150** ^The full amount of memory used by the schemas is reported, even if the 8151** schema memory is shared with other database connections due to 8152** [shared cache mode] being enabled. 8153** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 8154** 8155** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 8156** <dd>This parameter returns the approximate number of bytes of heap 8157** and lookaside memory used by all prepared statements associated with 8158** the database connection.)^ 8159** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 8160** </dd> 8161** 8162** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 8163** <dd>This parameter returns the number of pager cache hits that have 8164** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 8165** is always 0. 8166** </dd> 8167** 8168** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 8169** <dd>This parameter returns the number of pager cache misses that have 8170** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 8171** is always 0. 8172** </dd> 8173** 8174** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 8175** <dd>This parameter returns the number of dirty cache entries that have 8176** been written to disk. Specifically, the number of pages written to the 8177** wal file in wal mode databases, or the number of pages written to the 8178** database file in rollback mode databases. Any pages written as part of 8179** transaction rollback or database recovery operations are not included. 8180** If an IO or other error occurs while writing a page to disk, the effect 8181** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 8182** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 8183** </dd> 8184** 8185** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 8186** <dd>This parameter returns the number of dirty cache entries that have 8187** been written to disk in the middle of a transaction due to the page 8188** cache overflowing. Transactions are more efficient if they are written 8189** to disk all at once. When pages spill mid-transaction, that introduces 8190** additional overhead. This parameter can be used help identify 8191** inefficiencies that can be resolved by increasing the cache size. 8192** </dd> 8193** 8194** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 8195** <dd>This parameter returns zero for the current value if and only if 8196** all foreign key constraints (deferred or immediate) have been 8197** resolved.)^ ^The highwater mark is always 0. 8198** </dd> 8199** </dl> 8200*/ 8201#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 8202#define SQLITE_DBSTATUS_CACHE_USED 1 8203#define SQLITE_DBSTATUS_SCHEMA_USED 2 8204#define SQLITE_DBSTATUS_STMT_USED 3 8205#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 8206#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 8207#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 8208#define SQLITE_DBSTATUS_CACHE_HIT 7 8209#define SQLITE_DBSTATUS_CACHE_MISS 8 8210#define SQLITE_DBSTATUS_CACHE_WRITE 9 8211#define SQLITE_DBSTATUS_DEFERRED_FKS 10 8212#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 8213#define SQLITE_DBSTATUS_CACHE_SPILL 12 8214#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 8215 8216 8217/* 8218** CAPI3REF: Prepared Statement Status 8219** METHOD: sqlite3_stmt 8220** 8221** ^(Each prepared statement maintains various 8222** [SQLITE_STMTSTATUS counters] that measure the number 8223** of times it has performed specific operations.)^ These counters can 8224** be used to monitor the performance characteristics of the prepared 8225** statements. For example, if the number of table steps greatly exceeds 8226** the number of table searches or result rows, that would tend to indicate 8227** that the prepared statement is using a full table scan rather than 8228** an index. 8229** 8230** ^(This interface is used to retrieve and reset counter values from 8231** a [prepared statement]. The first argument is the prepared statement 8232** object to be interrogated. The second argument 8233** is an integer code for a specific [SQLITE_STMTSTATUS counter] 8234** to be interrogated.)^ 8235** ^The current value of the requested counter is returned. 8236** ^If the resetFlg is true, then the counter is reset to zero after this 8237** interface call returns. 8238** 8239** See also: [sqlite3_status()] and [sqlite3_db_status()]. 8240*/ 8241int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 8242 8243/* 8244** CAPI3REF: Status Parameters for prepared statements 8245** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 8246** 8247** These preprocessor macros define integer codes that name counter 8248** values associated with the [sqlite3_stmt_status()] interface. 8249** The meanings of the various counters are as follows: 8250** 8251** <dl> 8252** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 8253** <dd>^This is the number of times that SQLite has stepped forward in 8254** a table as part of a full table scan. Large numbers for this counter 8255** may indicate opportunities for performance improvement through 8256** careful use of indices.</dd> 8257** 8258** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 8259** <dd>^This is the number of sort operations that have occurred. 8260** A non-zero value in this counter may indicate an opportunity to 8261** improvement performance through careful use of indices.</dd> 8262** 8263** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 8264** <dd>^This is the number of rows inserted into transient indices that 8265** were created automatically in order to help joins run faster. 8266** A non-zero value in this counter may indicate an opportunity to 8267** improvement performance by adding permanent indices that do not 8268** need to be reinitialized each time the statement is run.</dd> 8269** 8270** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 8271** <dd>^This is the number of virtual machine operations executed 8272** by the prepared statement if that number is less than or equal 8273** to 2147483647. The number of virtual machine operations can be 8274** used as a proxy for the total work done by the prepared statement. 8275** If the number of virtual machine operations exceeds 2147483647 8276** then the value returned by this statement status code is undefined. 8277** 8278** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 8279** <dd>^This is the number of times that the prepare statement has been 8280** automatically regenerated due to schema changes or changes to 8281** [bound parameters] that might affect the query plan. 8282** 8283** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 8284** <dd>^This is the number of times that the prepared statement has 8285** been run. A single "run" for the purposes of this counter is one 8286** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 8287** The counter is incremented on the first [sqlite3_step()] call of each 8288** cycle. 8289** 8290** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 8291** <dd>^This is the approximate number of bytes of heap memory 8292** used to store the prepared statement. ^This value is not actually 8293** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 8294** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 8295** </dd> 8296** </dl> 8297*/ 8298#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 8299#define SQLITE_STMTSTATUS_SORT 2 8300#define SQLITE_STMTSTATUS_AUTOINDEX 3 8301#define SQLITE_STMTSTATUS_VM_STEP 4 8302#define SQLITE_STMTSTATUS_REPREPARE 5 8303#define SQLITE_STMTSTATUS_RUN 6 8304#define SQLITE_STMTSTATUS_MEMUSED 99 8305 8306/* 8307** CAPI3REF: Custom Page Cache Object 8308** 8309** The sqlite3_pcache type is opaque. It is implemented by 8310** the pluggable module. The SQLite core has no knowledge of 8311** its size or internal structure and never deals with the 8312** sqlite3_pcache object except by holding and passing pointers 8313** to the object. 8314** 8315** See [sqlite3_pcache_methods2] for additional information. 8316*/ 8317typedef struct sqlite3_pcache sqlite3_pcache; 8318 8319/* 8320** CAPI3REF: Custom Page Cache Object 8321** 8322** The sqlite3_pcache_page object represents a single page in the 8323** page cache. The page cache will allocate instances of this 8324** object. Various methods of the page cache use pointers to instances 8325** of this object as parameters or as their return value. 8326** 8327** See [sqlite3_pcache_methods2] for additional information. 8328*/ 8329typedef struct sqlite3_pcache_page sqlite3_pcache_page; 8330struct sqlite3_pcache_page { 8331 void *pBuf; /* The content of the page */ 8332 void *pExtra; /* Extra information associated with the page */ 8333}; 8334 8335/* 8336** CAPI3REF: Application Defined Page Cache. 8337** KEYWORDS: {page cache} 8338** 8339** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 8340** register an alternative page cache implementation by passing in an 8341** instance of the sqlite3_pcache_methods2 structure.)^ 8342** In many applications, most of the heap memory allocated by 8343** SQLite is used for the page cache. 8344** By implementing a 8345** custom page cache using this API, an application can better control 8346** the amount of memory consumed by SQLite, the way in which 8347** that memory is allocated and released, and the policies used to 8348** determine exactly which parts of a database file are cached and for 8349** how long. 8350** 8351** The alternative page cache mechanism is an 8352** extreme measure that is only needed by the most demanding applications. 8353** The built-in page cache is recommended for most uses. 8354** 8355** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 8356** internal buffer by SQLite within the call to [sqlite3_config]. Hence 8357** the application may discard the parameter after the call to 8358** [sqlite3_config()] returns.)^ 8359** 8360** [[the xInit() page cache method]] 8361** ^(The xInit() method is called once for each effective 8362** call to [sqlite3_initialize()])^ 8363** (usually only once during the lifetime of the process). ^(The xInit() 8364** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 8365** The intent of the xInit() method is to set up global data structures 8366** required by the custom page cache implementation. 8367** ^(If the xInit() method is NULL, then the 8368** built-in default page cache is used instead of the application defined 8369** page cache.)^ 8370** 8371** [[the xShutdown() page cache method]] 8372** ^The xShutdown() method is called by [sqlite3_shutdown()]. 8373** It can be used to clean up 8374** any outstanding resources before process shutdown, if required. 8375** ^The xShutdown() method may be NULL. 8376** 8377** ^SQLite automatically serializes calls to the xInit method, 8378** so the xInit method need not be threadsafe. ^The 8379** xShutdown method is only called from [sqlite3_shutdown()] so it does 8380** not need to be threadsafe either. All other methods must be threadsafe 8381** in multithreaded applications. 8382** 8383** ^SQLite will never invoke xInit() more than once without an intervening 8384** call to xShutdown(). 8385** 8386** [[the xCreate() page cache methods]] 8387** ^SQLite invokes the xCreate() method to construct a new cache instance. 8388** SQLite will typically create one cache instance for each open database file, 8389** though this is not guaranteed. ^The 8390** first parameter, szPage, is the size in bytes of the pages that must 8391** be allocated by the cache. ^szPage will always a power of two. ^The 8392** second parameter szExtra is a number of bytes of extra storage 8393** associated with each page cache entry. ^The szExtra parameter will 8394** a number less than 250. SQLite will use the 8395** extra szExtra bytes on each page to store metadata about the underlying 8396** database page on disk. The value passed into szExtra depends 8397** on the SQLite version, the target platform, and how SQLite was compiled. 8398** ^The third argument to xCreate(), bPurgeable, is true if the cache being 8399** created will be used to cache database pages of a file stored on disk, or 8400** false if it is used for an in-memory database. The cache implementation 8401** does not have to do anything special based with the value of bPurgeable; 8402** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 8403** never invoke xUnpin() except to deliberately delete a page. 8404** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 8405** false will always have the "discard" flag set to true. 8406** ^Hence, a cache created with bPurgeable false will 8407** never contain any unpinned pages. 8408** 8409** [[the xCachesize() page cache method]] 8410** ^(The xCachesize() method may be called at any time by SQLite to set the 8411** suggested maximum cache-size (number of pages stored by) the cache 8412** instance passed as the first argument. This is the value configured using 8413** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 8414** parameter, the implementation is not required to do anything with this 8415** value; it is advisory only. 8416** 8417** [[the xPagecount() page cache methods]] 8418** The xPagecount() method must return the number of pages currently 8419** stored in the cache, both pinned and unpinned. 8420** 8421** [[the xFetch() page cache methods]] 8422** The xFetch() method locates a page in the cache and returns a pointer to 8423** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 8424** The pBuf element of the returned sqlite3_pcache_page object will be a 8425** pointer to a buffer of szPage bytes used to store the content of a 8426** single database page. The pExtra element of sqlite3_pcache_page will be 8427** a pointer to the szExtra bytes of extra storage that SQLite has requested 8428** for each entry in the page cache. 8429** 8430** The page to be fetched is determined by the key. ^The minimum key value 8431** is 1. After it has been retrieved using xFetch, the page is considered 8432** to be "pinned". 8433** 8434** If the requested page is already in the page cache, then the page cache 8435** implementation must return a pointer to the page buffer with its content 8436** intact. If the requested page is not already in the cache, then the 8437** cache implementation should use the value of the createFlag 8438** parameter to help it determined what action to take: 8439** 8440** <table border=1 width=85% align=center> 8441** <tr><th> createFlag <th> Behavior when page is not already in cache 8442** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 8443** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 8444** Otherwise return NULL. 8445** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 8446** NULL if allocating a new page is effectively impossible. 8447** </table> 8448** 8449** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 8450** will only use a createFlag of 2 after a prior call with a createFlag of 1 8451** failed.)^ In between the xFetch() calls, SQLite may 8452** attempt to unpin one or more cache pages by spilling the content of 8453** pinned pages to disk and synching the operating system disk cache. 8454** 8455** [[the xUnpin() page cache method]] 8456** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 8457** as its second argument. If the third parameter, discard, is non-zero, 8458** then the page must be evicted from the cache. 8459** ^If the discard parameter is 8460** zero, then the page may be discarded or retained at the discretion of 8461** page cache implementation. ^The page cache implementation 8462** may choose to evict unpinned pages at any time. 8463** 8464** The cache must not perform any reference counting. A single 8465** call to xUnpin() unpins the page regardless of the number of prior calls 8466** to xFetch(). 8467** 8468** [[the xRekey() page cache methods]] 8469** The xRekey() method is used to change the key value associated with the 8470** page passed as the second argument. If the cache 8471** previously contains an entry associated with newKey, it must be 8472** discarded. ^Any prior cache entry associated with newKey is guaranteed not 8473** to be pinned. 8474** 8475** When SQLite calls the xTruncate() method, the cache must discard all 8476** existing cache entries with page numbers (keys) greater than or equal 8477** to the value of the iLimit parameter passed to xTruncate(). If any 8478** of these pages are pinned, they are implicitly unpinned, meaning that 8479** they can be safely discarded. 8480** 8481** [[the xDestroy() page cache method]] 8482** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 8483** All resources associated with the specified cache should be freed. ^After 8484** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 8485** handle invalid, and will not use it with any other sqlite3_pcache_methods2 8486** functions. 8487** 8488** [[the xShrink() page cache method]] 8489** ^SQLite invokes the xShrink() method when it wants the page cache to 8490** free up as much of heap memory as possible. The page cache implementation 8491** is not obligated to free any memory, but well-behaved implementations should 8492** do their best. 8493*/ 8494typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 8495struct sqlite3_pcache_methods2 { 8496 int iVersion; 8497 void *pArg; 8498 int (*xInit)(void*); 8499 void (*xShutdown)(void*); 8500 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 8501 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8502 int (*xPagecount)(sqlite3_pcache*); 8503 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8504 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 8505 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 8506 unsigned oldKey, unsigned newKey); 8507 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8508 void (*xDestroy)(sqlite3_pcache*); 8509 void (*xShrink)(sqlite3_pcache*); 8510}; 8511 8512/* 8513** This is the obsolete pcache_methods object that has now been replaced 8514** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 8515** retained in the header file for backwards compatibility only. 8516*/ 8517typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 8518struct sqlite3_pcache_methods { 8519 void *pArg; 8520 int (*xInit)(void*); 8521 void (*xShutdown)(void*); 8522 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 8523 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8524 int (*xPagecount)(sqlite3_pcache*); 8525 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8526 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 8527 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 8528 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8529 void (*xDestroy)(sqlite3_pcache*); 8530}; 8531 8532 8533/* 8534** CAPI3REF: Online Backup Object 8535** 8536** The sqlite3_backup object records state information about an ongoing 8537** online backup operation. ^The sqlite3_backup object is created by 8538** a call to [sqlite3_backup_init()] and is destroyed by a call to 8539** [sqlite3_backup_finish()]. 8540** 8541** See Also: [Using the SQLite Online Backup API] 8542*/ 8543typedef struct sqlite3_backup sqlite3_backup; 8544 8545/* 8546** CAPI3REF: Online Backup API. 8547** 8548** The backup API copies the content of one database into another. 8549** It is useful either for creating backups of databases or 8550** for copying in-memory databases to or from persistent files. 8551** 8552** See Also: [Using the SQLite Online Backup API] 8553** 8554** ^SQLite holds a write transaction open on the destination database file 8555** for the duration of the backup operation. 8556** ^The source database is read-locked only while it is being read; 8557** it is not locked continuously for the entire backup operation. 8558** ^Thus, the backup may be performed on a live source database without 8559** preventing other database connections from 8560** reading or writing to the source database while the backup is underway. 8561** 8562** ^(To perform a backup operation: 8563** <ol> 8564** <li><b>sqlite3_backup_init()</b> is called once to initialize the 8565** backup, 8566** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 8567** the data between the two databases, and finally 8568** <li><b>sqlite3_backup_finish()</b> is called to release all resources 8569** associated with the backup operation. 8570** </ol>)^ 8571** There should be exactly one call to sqlite3_backup_finish() for each 8572** successful call to sqlite3_backup_init(). 8573** 8574** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 8575** 8576** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 8577** [database connection] associated with the destination database 8578** and the database name, respectively. 8579** ^The database name is "main" for the main database, "temp" for the 8580** temporary database, or the name specified after the AS keyword in 8581** an [ATTACH] statement for an attached database. 8582** ^The S and M arguments passed to 8583** sqlite3_backup_init(D,N,S,M) identify the [database connection] 8584** and database name of the source database, respectively. 8585** ^The source and destination [database connections] (parameters S and D) 8586** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 8587** an error. 8588** 8589** ^A call to sqlite3_backup_init() will fail, returning NULL, if 8590** there is already a read or read-write transaction open on the 8591** destination database. 8592** 8593** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 8594** returned and an error code and error message are stored in the 8595** destination [database connection] D. 8596** ^The error code and message for the failed call to sqlite3_backup_init() 8597** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 8598** [sqlite3_errmsg16()] functions. 8599** ^A successful call to sqlite3_backup_init() returns a pointer to an 8600** [sqlite3_backup] object. 8601** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 8602** sqlite3_backup_finish() functions to perform the specified backup 8603** operation. 8604** 8605** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 8606** 8607** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 8608** the source and destination databases specified by [sqlite3_backup] object B. 8609** ^If N is negative, all remaining source pages are copied. 8610** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 8611** are still more pages to be copied, then the function returns [SQLITE_OK]. 8612** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 8613** from source to destination, then it returns [SQLITE_DONE]. 8614** ^If an error occurs while running sqlite3_backup_step(B,N), 8615** then an [error code] is returned. ^As well as [SQLITE_OK] and 8616** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 8617** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 8618** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 8619** 8620** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 8621** <ol> 8622** <li> the destination database was opened read-only, or 8623** <li> the destination database is using write-ahead-log journaling 8624** and the destination and source page sizes differ, or 8625** <li> the destination database is an in-memory database and the 8626** destination and source page sizes differ. 8627** </ol>)^ 8628** 8629** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 8630** the [sqlite3_busy_handler | busy-handler function] 8631** is invoked (if one is specified). ^If the 8632** busy-handler returns non-zero before the lock is available, then 8633** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 8634** sqlite3_backup_step() can be retried later. ^If the source 8635** [database connection] 8636** is being used to write to the source database when sqlite3_backup_step() 8637** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 8638** case the call to sqlite3_backup_step() can be retried later on. ^(If 8639** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 8640** [SQLITE_READONLY] is returned, then 8641** there is no point in retrying the call to sqlite3_backup_step(). These 8642** errors are considered fatal.)^ The application must accept 8643** that the backup operation has failed and pass the backup operation handle 8644** to the sqlite3_backup_finish() to release associated resources. 8645** 8646** ^The first call to sqlite3_backup_step() obtains an exclusive lock 8647** on the destination file. ^The exclusive lock is not released until either 8648** sqlite3_backup_finish() is called or the backup operation is complete 8649** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 8650** sqlite3_backup_step() obtains a [shared lock] on the source database that 8651** lasts for the duration of the sqlite3_backup_step() call. 8652** ^Because the source database is not locked between calls to 8653** sqlite3_backup_step(), the source database may be modified mid-way 8654** through the backup process. ^If the source database is modified by an 8655** external process or via a database connection other than the one being 8656** used by the backup operation, then the backup will be automatically 8657** restarted by the next call to sqlite3_backup_step(). ^If the source 8658** database is modified by the using the same database connection as is used 8659** by the backup operation, then the backup database is automatically 8660** updated at the same time. 8661** 8662** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 8663** 8664** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 8665** application wishes to abandon the backup operation, the application 8666** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 8667** ^The sqlite3_backup_finish() interfaces releases all 8668** resources associated with the [sqlite3_backup] object. 8669** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 8670** active write-transaction on the destination database is rolled back. 8671** The [sqlite3_backup] object is invalid 8672** and may not be used following a call to sqlite3_backup_finish(). 8673** 8674** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 8675** sqlite3_backup_step() errors occurred, regardless or whether or not 8676** sqlite3_backup_step() completed. 8677** ^If an out-of-memory condition or IO error occurred during any prior 8678** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 8679** sqlite3_backup_finish() returns the corresponding [error code]. 8680** 8681** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 8682** is not a permanent error and does not affect the return value of 8683** sqlite3_backup_finish(). 8684** 8685** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 8686** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 8687** 8688** ^The sqlite3_backup_remaining() routine returns the number of pages still 8689** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 8690** ^The sqlite3_backup_pagecount() routine returns the total number of pages 8691** in the source database at the conclusion of the most recent 8692** sqlite3_backup_step(). 8693** ^(The values returned by these functions are only updated by 8694** sqlite3_backup_step(). If the source database is modified in a way that 8695** changes the size of the source database or the number of pages remaining, 8696** those changes are not reflected in the output of sqlite3_backup_pagecount() 8697** and sqlite3_backup_remaining() until after the next 8698** sqlite3_backup_step().)^ 8699** 8700** <b>Concurrent Usage of Database Handles</b> 8701** 8702** ^The source [database connection] may be used by the application for other 8703** purposes while a backup operation is underway or being initialized. 8704** ^If SQLite is compiled and configured to support threadsafe database 8705** connections, then the source database connection may be used concurrently 8706** from within other threads. 8707** 8708** However, the application must guarantee that the destination 8709** [database connection] is not passed to any other API (by any thread) after 8710** sqlite3_backup_init() is called and before the corresponding call to 8711** sqlite3_backup_finish(). SQLite does not currently check to see 8712** if the application incorrectly accesses the destination [database connection] 8713** and so no error code is reported, but the operations may malfunction 8714** nevertheless. Use of the destination database connection while a 8715** backup is in progress might also also cause a mutex deadlock. 8716** 8717** If running in [shared cache mode], the application must 8718** guarantee that the shared cache used by the destination database 8719** is not accessed while the backup is running. In practice this means 8720** that the application must guarantee that the disk file being 8721** backed up to is not accessed by any connection within the process, 8722** not just the specific connection that was passed to sqlite3_backup_init(). 8723** 8724** The [sqlite3_backup] object itself is partially threadsafe. Multiple 8725** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 8726** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 8727** APIs are not strictly speaking threadsafe. If they are invoked at the 8728** same time as another thread is invoking sqlite3_backup_step() it is 8729** possible that they return invalid values. 8730*/ 8731sqlite3_backup *sqlite3_backup_init( 8732 sqlite3 *pDest, /* Destination database handle */ 8733 const char *zDestName, /* Destination database name */ 8734 sqlite3 *pSource, /* Source database handle */ 8735 const char *zSourceName /* Source database name */ 8736); 8737int sqlite3_backup_step(sqlite3_backup *p, int nPage); 8738int sqlite3_backup_finish(sqlite3_backup *p); 8739int sqlite3_backup_remaining(sqlite3_backup *p); 8740int sqlite3_backup_pagecount(sqlite3_backup *p); 8741 8742/* 8743** CAPI3REF: Unlock Notification 8744** METHOD: sqlite3 8745** 8746** ^When running in shared-cache mode, a database operation may fail with 8747** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 8748** individual tables within the shared-cache cannot be obtained. See 8749** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 8750** ^This API may be used to register a callback that SQLite will invoke 8751** when the connection currently holding the required lock relinquishes it. 8752** ^This API is only available if the library was compiled with the 8753** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 8754** 8755** See Also: [Using the SQLite Unlock Notification Feature]. 8756** 8757** ^Shared-cache locks are released when a database connection concludes 8758** its current transaction, either by committing it or rolling it back. 8759** 8760** ^When a connection (known as the blocked connection) fails to obtain a 8761** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 8762** identity of the database connection (the blocking connection) that 8763** has locked the required resource is stored internally. ^After an 8764** application receives an SQLITE_LOCKED error, it may call the 8765** sqlite3_unlock_notify() method with the blocked connection handle as 8766** the first argument to register for a callback that will be invoked 8767** when the blocking connections current transaction is concluded. ^The 8768** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 8769** call that concludes the blocking connection's transaction. 8770** 8771** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 8772** there is a chance that the blocking connection will have already 8773** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 8774** If this happens, then the specified callback is invoked immediately, 8775** from within the call to sqlite3_unlock_notify().)^ 8776** 8777** ^If the blocked connection is attempting to obtain a write-lock on a 8778** shared-cache table, and more than one other connection currently holds 8779** a read-lock on the same table, then SQLite arbitrarily selects one of 8780** the other connections to use as the blocking connection. 8781** 8782** ^(There may be at most one unlock-notify callback registered by a 8783** blocked connection. If sqlite3_unlock_notify() is called when the 8784** blocked connection already has a registered unlock-notify callback, 8785** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 8786** called with a NULL pointer as its second argument, then any existing 8787** unlock-notify callback is canceled. ^The blocked connections 8788** unlock-notify callback may also be canceled by closing the blocked 8789** connection using [sqlite3_close()]. 8790** 8791** The unlock-notify callback is not reentrant. If an application invokes 8792** any sqlite3_xxx API functions from within an unlock-notify callback, a 8793** crash or deadlock may be the result. 8794** 8795** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 8796** returns SQLITE_OK. 8797** 8798** <b>Callback Invocation Details</b> 8799** 8800** When an unlock-notify callback is registered, the application provides a 8801** single void* pointer that is passed to the callback when it is invoked. 8802** However, the signature of the callback function allows SQLite to pass 8803** it an array of void* context pointers. The first argument passed to 8804** an unlock-notify callback is a pointer to an array of void* pointers, 8805** and the second is the number of entries in the array. 8806** 8807** When a blocking connection's transaction is concluded, there may be 8808** more than one blocked connection that has registered for an unlock-notify 8809** callback. ^If two or more such blocked connections have specified the 8810** same callback function, then instead of invoking the callback function 8811** multiple times, it is invoked once with the set of void* context pointers 8812** specified by the blocked connections bundled together into an array. 8813** This gives the application an opportunity to prioritize any actions 8814** related to the set of unblocked database connections. 8815** 8816** <b>Deadlock Detection</b> 8817** 8818** Assuming that after registering for an unlock-notify callback a 8819** database waits for the callback to be issued before taking any further 8820** action (a reasonable assumption), then using this API may cause the 8821** application to deadlock. For example, if connection X is waiting for 8822** connection Y's transaction to be concluded, and similarly connection 8823** Y is waiting on connection X's transaction, then neither connection 8824** will proceed and the system may remain deadlocked indefinitely. 8825** 8826** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 8827** detection. ^If a given call to sqlite3_unlock_notify() would put the 8828** system in a deadlocked state, then SQLITE_LOCKED is returned and no 8829** unlock-notify callback is registered. The system is said to be in 8830** a deadlocked state if connection A has registered for an unlock-notify 8831** callback on the conclusion of connection B's transaction, and connection 8832** B has itself registered for an unlock-notify callback when connection 8833** A's transaction is concluded. ^Indirect deadlock is also detected, so 8834** the system is also considered to be deadlocked if connection B has 8835** registered for an unlock-notify callback on the conclusion of connection 8836** C's transaction, where connection C is waiting on connection A. ^Any 8837** number of levels of indirection are allowed. 8838** 8839** <b>The "DROP TABLE" Exception</b> 8840** 8841** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 8842** always appropriate to call sqlite3_unlock_notify(). There is however, 8843** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 8844** SQLite checks if there are any currently executing SELECT statements 8845** that belong to the same connection. If there are, SQLITE_LOCKED is 8846** returned. In this case there is no "blocking connection", so invoking 8847** sqlite3_unlock_notify() results in the unlock-notify callback being 8848** invoked immediately. If the application then re-attempts the "DROP TABLE" 8849** or "DROP INDEX" query, an infinite loop might be the result. 8850** 8851** One way around this problem is to check the extended error code returned 8852** by an sqlite3_step() call. ^(If there is a blocking connection, then the 8853** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 8854** the special "DROP TABLE/INDEX" case, the extended error code is just 8855** SQLITE_LOCKED.)^ 8856*/ 8857int sqlite3_unlock_notify( 8858 sqlite3 *pBlocked, /* Waiting connection */ 8859 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 8860 void *pNotifyArg /* Argument to pass to xNotify */ 8861); 8862 8863 8864/* 8865** CAPI3REF: String Comparison 8866** 8867** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 8868** and extensions to compare the contents of two buffers containing UTF-8 8869** strings in a case-independent fashion, using the same definition of "case 8870** independence" that SQLite uses internally when comparing identifiers. 8871*/ 8872int sqlite3_stricmp(const char *, const char *); 8873int sqlite3_strnicmp(const char *, const char *, int); 8874 8875/* 8876** CAPI3REF: String Globbing 8877* 8878** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 8879** string X matches the [GLOB] pattern P. 8880** ^The definition of [GLOB] pattern matching used in 8881** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 8882** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 8883** is case sensitive. 8884** 8885** Note that this routine returns zero on a match and non-zero if the strings 8886** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8887** 8888** See also: [sqlite3_strlike()]. 8889*/ 8890int sqlite3_strglob(const char *zGlob, const char *zStr); 8891 8892/* 8893** CAPI3REF: String LIKE Matching 8894* 8895** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 8896** string X matches the [LIKE] pattern P with escape character E. 8897** ^The definition of [LIKE] pattern matching used in 8898** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 8899** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 8900** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 8901** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 8902** insensitive - equivalent upper and lower case ASCII characters match 8903** one another. 8904** 8905** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 8906** only ASCII characters are case folded. 8907** 8908** Note that this routine returns zero on a match and non-zero if the strings 8909** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8910** 8911** See also: [sqlite3_strglob()]. 8912*/ 8913int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8914 8915/* 8916** CAPI3REF: Error Logging Interface 8917** 8918** ^The [sqlite3_log()] interface writes a message into the [error log] 8919** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8920** ^If logging is enabled, the zFormat string and subsequent arguments are 8921** used with [sqlite3_snprintf()] to generate the final output string. 8922** 8923** The sqlite3_log() interface is intended for use by extensions such as 8924** virtual tables, collating functions, and SQL functions. While there is 8925** nothing to prevent an application from calling sqlite3_log(), doing so 8926** is considered bad form. 8927** 8928** The zFormat string must not be NULL. 8929** 8930** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8931** will not use dynamically allocated memory. The log message is stored in 8932** a fixed-length buffer on the stack. If the log message is longer than 8933** a few hundred characters, it will be truncated to the length of the 8934** buffer. 8935*/ 8936void sqlite3_log(int iErrCode, const char *zFormat, ...); 8937 8938/* 8939** CAPI3REF: Write-Ahead Log Commit Hook 8940** METHOD: sqlite3 8941** 8942** ^The [sqlite3_wal_hook()] function is used to register a callback that 8943** is invoked each time data is committed to a database in wal mode. 8944** 8945** ^(The callback is invoked by SQLite after the commit has taken place and 8946** the associated write-lock on the database released)^, so the implementation 8947** may read, write or [checkpoint] the database as required. 8948** 8949** ^The first parameter passed to the callback function when it is invoked 8950** is a copy of the third parameter passed to sqlite3_wal_hook() when 8951** registering the callback. ^The second is a copy of the database handle. 8952** ^The third parameter is the name of the database that was written to - 8953** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8954** is the number of pages currently in the write-ahead log file, 8955** including those that were just committed. 8956** 8957** The callback function should normally return [SQLITE_OK]. ^If an error 8958** code is returned, that error will propagate back up through the 8959** SQLite code base to cause the statement that provoked the callback 8960** to report an error, though the commit will have still occurred. If the 8961** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8962** that does not correspond to any valid SQLite error code, the results 8963** are undefined. 8964** 8965** A single database handle may have at most a single write-ahead log callback 8966** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8967** previously registered write-ahead log callback. ^Note that the 8968** [sqlite3_wal_autocheckpoint()] interface and the 8969** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8970** overwrite any prior [sqlite3_wal_hook()] settings. 8971*/ 8972void *sqlite3_wal_hook( 8973 sqlite3*, 8974 int(*)(void *,sqlite3*,const char*,int), 8975 void* 8976); 8977 8978/* 8979** CAPI3REF: Configure an auto-checkpoint 8980** METHOD: sqlite3 8981** 8982** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8983** [sqlite3_wal_hook()] that causes any database on [database connection] D 8984** to automatically [checkpoint] 8985** after committing a transaction if there are N or 8986** more frames in the [write-ahead log] file. ^Passing zero or 8987** a negative value as the nFrame parameter disables automatic 8988** checkpoints entirely. 8989** 8990** ^The callback registered by this function replaces any existing callback 8991** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8992** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8993** configured by this function. 8994** 8995** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8996** from SQL. 8997** 8998** ^Checkpoints initiated by this mechanism are 8999** [sqlite3_wal_checkpoint_v2|PASSIVE]. 9000** 9001** ^Every new [database connection] defaults to having the auto-checkpoint 9002** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 9003** pages. The use of this interface 9004** is only necessary if the default setting is found to be suboptimal 9005** for a particular application. 9006*/ 9007int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 9008 9009/* 9010** CAPI3REF: Checkpoint a database 9011** METHOD: sqlite3 9012** 9013** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 9014** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 9015** 9016** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 9017** [write-ahead log] for database X on [database connection] D to be 9018** transferred into the database file and for the write-ahead log to 9019** be reset. See the [checkpointing] documentation for addition 9020** information. 9021** 9022** This interface used to be the only way to cause a checkpoint to 9023** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 9024** interface was added. This interface is retained for backwards 9025** compatibility and as a convenience for applications that need to manually 9026** start a callback but which do not need the full power (and corresponding 9027** complication) of [sqlite3_wal_checkpoint_v2()]. 9028*/ 9029int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 9030 9031/* 9032** CAPI3REF: Checkpoint a database 9033** METHOD: sqlite3 9034** 9035** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 9036** operation on database X of [database connection] D in mode M. Status 9037** information is written back into integers pointed to by L and C.)^ 9038** ^(The M parameter must be a valid [checkpoint mode]:)^ 9039** 9040** <dl> 9041** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 9042** ^Checkpoint as many frames as possible without waiting for any database 9043** readers or writers to finish, then sync the database file if all frames 9044** in the log were checkpointed. ^The [busy-handler callback] 9045** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 9046** ^On the other hand, passive mode might leave the checkpoint unfinished 9047** if there are concurrent readers or writers. 9048** 9049** <dt>SQLITE_CHECKPOINT_FULL<dd> 9050** ^This mode blocks (it invokes the 9051** [sqlite3_busy_handler|busy-handler callback]) until there is no 9052** database writer and all readers are reading from the most recent database 9053** snapshot. ^It then checkpoints all frames in the log file and syncs the 9054** database file. ^This mode blocks new database writers while it is pending, 9055** but new database readers are allowed to continue unimpeded. 9056** 9057** <dt>SQLITE_CHECKPOINT_RESTART<dd> 9058** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 9059** that after checkpointing the log file it blocks (calls the 9060** [busy-handler callback]) 9061** until all readers are reading from the database file only. ^This ensures 9062** that the next writer will restart the log file from the beginning. 9063** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 9064** database writer attempts while it is pending, but does not impede readers. 9065** 9066** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 9067** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 9068** addition that it also truncates the log file to zero bytes just prior 9069** to a successful return. 9070** </dl> 9071** 9072** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 9073** the log file or to -1 if the checkpoint could not run because 9074** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 9075** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 9076** log file (including any that were already checkpointed before the function 9077** was called) or to -1 if the checkpoint could not run due to an error or 9078** because the database is not in WAL mode. ^Note that upon successful 9079** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 9080** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 9081** 9082** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 9083** any other process is running a checkpoint operation at the same time, the 9084** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 9085** busy-handler configured, it will not be invoked in this case. 9086** 9087** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 9088** exclusive "writer" lock on the database file. ^If the writer lock cannot be 9089** obtained immediately, and a busy-handler is configured, it is invoked and 9090** the writer lock retried until either the busy-handler returns 0 or the lock 9091** is successfully obtained. ^The busy-handler is also invoked while waiting for 9092** database readers as described above. ^If the busy-handler returns 0 before 9093** the writer lock is obtained or while waiting for database readers, the 9094** checkpoint operation proceeds from that point in the same way as 9095** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 9096** without blocking any further. ^SQLITE_BUSY is returned in this case. 9097** 9098** ^If parameter zDb is NULL or points to a zero length string, then the 9099** specified operation is attempted on all WAL databases [attached] to 9100** [database connection] db. In this case the 9101** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 9102** an SQLITE_BUSY error is encountered when processing one or more of the 9103** attached WAL databases, the operation is still attempted on any remaining 9104** attached databases and SQLITE_BUSY is returned at the end. ^If any other 9105** error occurs while processing an attached database, processing is abandoned 9106** and the error code is returned to the caller immediately. ^If no error 9107** (SQLITE_BUSY or otherwise) is encountered while processing the attached 9108** databases, SQLITE_OK is returned. 9109** 9110** ^If database zDb is the name of an attached database that is not in WAL 9111** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 9112** zDb is not NULL (or a zero length string) and is not the name of any 9113** attached database, SQLITE_ERROR is returned to the caller. 9114** 9115** ^Unless it returns SQLITE_MISUSE, 9116** the sqlite3_wal_checkpoint_v2() interface 9117** sets the error information that is queried by 9118** [sqlite3_errcode()] and [sqlite3_errmsg()]. 9119** 9120** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 9121** from SQL. 9122*/ 9123int sqlite3_wal_checkpoint_v2( 9124 sqlite3 *db, /* Database handle */ 9125 const char *zDb, /* Name of attached database (or NULL) */ 9126 int eMode, /* SQLITE_CHECKPOINT_* value */ 9127 int *pnLog, /* OUT: Size of WAL log in frames */ 9128 int *pnCkpt /* OUT: Total number of frames checkpointed */ 9129); 9130 9131/* 9132** CAPI3REF: Checkpoint Mode Values 9133** KEYWORDS: {checkpoint mode} 9134** 9135** These constants define all valid values for the "checkpoint mode" passed 9136** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 9137** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 9138** meaning of each of these checkpoint modes. 9139*/ 9140#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 9141#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 9142#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 9143#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 9144 9145/* 9146** CAPI3REF: Virtual Table Interface Configuration 9147** 9148** This function may be called by either the [xConnect] or [xCreate] method 9149** of a [virtual table] implementation to configure 9150** various facets of the virtual table interface. 9151** 9152** If this interface is invoked outside the context of an xConnect or 9153** xCreate virtual table method then the behavior is undefined. 9154** 9155** In the call sqlite3_vtab_config(D,C,...) the D parameter is the 9156** [database connection] in which the virtual table is being created and 9157** which is passed in as the first argument to the [xConnect] or [xCreate] 9158** method that is invoking sqlite3_vtab_config(). The C parameter is one 9159** of the [virtual table configuration options]. The presence and meaning 9160** of parameters after C depend on which [virtual table configuration option] 9161** is used. 9162*/ 9163int sqlite3_vtab_config(sqlite3*, int op, ...); 9164 9165/* 9166** CAPI3REF: Virtual Table Configuration Options 9167** KEYWORDS: {virtual table configuration options} 9168** KEYWORDS: {virtual table configuration option} 9169** 9170** These macros define the various options to the 9171** [sqlite3_vtab_config()] interface that [virtual table] implementations 9172** can use to customize and optimize their behavior. 9173** 9174** <dl> 9175** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]] 9176** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt> 9177** <dd>Calls of the form 9178** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 9179** where X is an integer. If X is zero, then the [virtual table] whose 9180** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 9181** support constraints. In this configuration (which is the default) if 9182** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 9183** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 9184** specified as part of the users SQL statement, regardless of the actual 9185** ON CONFLICT mode specified. 9186** 9187** If X is non-zero, then the virtual table implementation guarantees 9188** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 9189** any modifications to internal or persistent data structures have been made. 9190** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 9191** is able to roll back a statement or database transaction, and abandon 9192** or continue processing the current SQL statement as appropriate. 9193** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 9194** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 9195** had been ABORT. 9196** 9197** Virtual table implementations that are required to handle OR REPLACE 9198** must do so within the [xUpdate] method. If a call to the 9199** [sqlite3_vtab_on_conflict()] function indicates that the current ON 9200** CONFLICT policy is REPLACE, the virtual table implementation should 9201** silently replace the appropriate rows within the xUpdate callback and 9202** return SQLITE_OK. Or, if this is not possible, it may return 9203** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 9204** constraint handling. 9205** </dd> 9206** 9207** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt> 9208** <dd>Calls of the form 9209** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the 9210** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9211** prohibits that virtual table from being used from within triggers and 9212** views. 9213** </dd> 9214** 9215** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt> 9216** <dd>Calls of the form 9217** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the 9218** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9219** identify that virtual table as being safe to use from within triggers 9220** and views. Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the 9221** virtual table can do no serious harm even if it is controlled by a 9222** malicious hacker. Developers should avoid setting the SQLITE_VTAB_INNOCUOUS 9223** flag unless absolutely necessary. 9224** </dd> 9225** </dl> 9226*/ 9227#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 9228#define SQLITE_VTAB_INNOCUOUS 2 9229#define SQLITE_VTAB_DIRECTONLY 3 9230 9231/* 9232** CAPI3REF: Determine The Virtual Table Conflict Policy 9233** 9234** This function may only be called from within a call to the [xUpdate] method 9235** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 9236** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 9237** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 9238** of the SQL statement that triggered the call to the [xUpdate] method of the 9239** [virtual table]. 9240*/ 9241int sqlite3_vtab_on_conflict(sqlite3 *); 9242 9243/* 9244** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 9245** 9246** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 9247** method of a [virtual table], then it might return true if the 9248** column is being fetched as part of an UPDATE operation during which the 9249** column value will not change. The virtual table implementation can use 9250** this hint as permission to substitute a return value that is less 9251** expensive to compute and that the corresponding 9252** [xUpdate] method understands as a "no-change" value. 9253** 9254** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 9255** the column is not changed by the UPDATE statement, then the xColumn 9256** method can optionally return without setting a result, without calling 9257** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 9258** In that case, [sqlite3_value_nochange(X)] will return true for the 9259** same column in the [xUpdate] method. 9260** 9261** The sqlite3_vtab_nochange() routine is an optimization. Virtual table 9262** implementations should continue to give a correct answer even if the 9263** sqlite3_vtab_nochange() interface were to always return false. In the 9264** current implementation, the sqlite3_vtab_nochange() interface does always 9265** returns false for the enhanced [UPDATE FROM] statement. 9266*/ 9267int sqlite3_vtab_nochange(sqlite3_context*); 9268 9269/* 9270** CAPI3REF: Determine The Collation For a Virtual Table Constraint 9271** 9272** This function may only be called from within a call to the [xBestIndex] 9273** method of a [virtual table]. 9274** 9275** The first argument must be the sqlite3_index_info object that is the 9276** first parameter to the xBestIndex() method. The second argument must be 9277** an index into the aConstraint[] array belonging to the sqlite3_index_info 9278** structure passed to xBestIndex. This function returns a pointer to a buffer 9279** containing the name of the collation sequence for the corresponding 9280** constraint. 9281*/ 9282SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 9283 9284/* 9285** CAPI3REF: Conflict resolution modes 9286** KEYWORDS: {conflict resolution mode} 9287** 9288** These constants are returned by [sqlite3_vtab_on_conflict()] to 9289** inform a [virtual table] implementation what the [ON CONFLICT] mode 9290** is for the SQL statement being evaluated. 9291** 9292** Note that the [SQLITE_IGNORE] constant is also used as a potential 9293** return value from the [sqlite3_set_authorizer()] callback and that 9294** [SQLITE_ABORT] is also a [result code]. 9295*/ 9296#define SQLITE_ROLLBACK 1 9297/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 9298#define SQLITE_FAIL 3 9299/* #define SQLITE_ABORT 4 // Also an error code */ 9300#define SQLITE_REPLACE 5 9301 9302/* 9303** CAPI3REF: Prepared Statement Scan Status Opcodes 9304** KEYWORDS: {scanstatus options} 9305** 9306** The following constants can be used for the T parameter to the 9307** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 9308** different metric for sqlite3_stmt_scanstatus() to return. 9309** 9310** When the value returned to V is a string, space to hold that string is 9311** managed by the prepared statement S and will be automatically freed when 9312** S is finalized. 9313** 9314** <dl> 9315** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 9316** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be 9317** set to the total number of times that the X-th loop has run.</dd> 9318** 9319** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 9320** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set 9321** to the total number of rows examined by all iterations of the X-th loop.</dd> 9322** 9323** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 9324** <dd>^The "double" variable pointed to by the V parameter will be set to the 9325** query planner's estimate for the average number of rows output from each 9326** iteration of the X-th loop. If the query planner's estimates was accurate, 9327** then this value will approximate the quotient NVISIT/NLOOP and the 9328** product of this value for all prior loops with the same SELECTID will 9329** be the NLOOP value for the current loop. 9330** 9331** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 9332** <dd>^The "const char *" variable pointed to by the V parameter will be set 9333** to a zero-terminated UTF-8 string containing the name of the index or table 9334** used for the X-th loop. 9335** 9336** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 9337** <dd>^The "const char *" variable pointed to by the V parameter will be set 9338** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 9339** description for the X-th loop. 9340** 9341** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 9342** <dd>^The "int" variable pointed to by the V parameter will be set to the 9343** "select-id" for the X-th loop. The select-id identifies which query or 9344** subquery the loop is part of. The main query has a select-id of zero. 9345** The select-id is the same value as is output in the first column 9346** of an [EXPLAIN QUERY PLAN] query. 9347** </dl> 9348*/ 9349#define SQLITE_SCANSTAT_NLOOP 0 9350#define SQLITE_SCANSTAT_NVISIT 1 9351#define SQLITE_SCANSTAT_EST 2 9352#define SQLITE_SCANSTAT_NAME 3 9353#define SQLITE_SCANSTAT_EXPLAIN 4 9354#define SQLITE_SCANSTAT_SELECTID 5 9355 9356/* 9357** CAPI3REF: Prepared Statement Scan Status 9358** METHOD: sqlite3_stmt 9359** 9360** This interface returns information about the predicted and measured 9361** performance for pStmt. Advanced applications can use this 9362** interface to compare the predicted and the measured performance and 9363** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 9364** 9365** Since this interface is expected to be rarely used, it is only 9366** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 9367** compile-time option. 9368** 9369** The "iScanStatusOp" parameter determines which status information to return. 9370** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 9371** of this interface is undefined. 9372** ^The requested measurement is written into a variable pointed to by 9373** the "pOut" parameter. 9374** Parameter "idx" identifies the specific loop to retrieve statistics for. 9375** Loops are numbered starting from zero. ^If idx is out of range - less than 9376** zero or greater than or equal to the total number of loops used to implement 9377** the statement - a non-zero value is returned and the variable that pOut 9378** points to is unchanged. 9379** 9380** ^Statistics might not be available for all loops in all statements. ^In cases 9381** where there exist loops with no available statistics, this function behaves 9382** as if the loop did not exist - it returns non-zero and leave the variable 9383** that pOut points to unchanged. 9384** 9385** See also: [sqlite3_stmt_scanstatus_reset()] 9386*/ 9387int sqlite3_stmt_scanstatus( 9388 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 9389 int idx, /* Index of loop to report on */ 9390 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 9391 void *pOut /* Result written here */ 9392); 9393 9394/* 9395** CAPI3REF: Zero Scan-Status Counters 9396** METHOD: sqlite3_stmt 9397** 9398** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 9399** 9400** This API is only available if the library is built with pre-processor 9401** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 9402*/ 9403void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 9404 9405/* 9406** CAPI3REF: Flush caches to disk mid-transaction 9407** METHOD: sqlite3 9408** 9409** ^If a write-transaction is open on [database connection] D when the 9410** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 9411** pages in the pager-cache that are not currently in use are written out 9412** to disk. A dirty page may be in use if a database cursor created by an 9413** active SQL statement is reading from it, or if it is page 1 of a database 9414** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 9415** interface flushes caches for all schemas - "main", "temp", and 9416** any [attached] databases. 9417** 9418** ^If this function needs to obtain extra database locks before dirty pages 9419** can be flushed to disk, it does so. ^If those locks cannot be obtained 9420** immediately and there is a busy-handler callback configured, it is invoked 9421** in the usual manner. ^If the required lock still cannot be obtained, then 9422** the database is skipped and an attempt made to flush any dirty pages 9423** belonging to the next (if any) database. ^If any databases are skipped 9424** because locks cannot be obtained, but no other error occurs, this 9425** function returns SQLITE_BUSY. 9426** 9427** ^If any other error occurs while flushing dirty pages to disk (for 9428** example an IO error or out-of-memory condition), then processing is 9429** abandoned and an SQLite [error code] is returned to the caller immediately. 9430** 9431** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 9432** 9433** ^This function does not set the database handle error code or message 9434** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 9435*/ 9436int sqlite3_db_cacheflush(sqlite3*); 9437 9438/* 9439** CAPI3REF: The pre-update hook. 9440** METHOD: sqlite3 9441** 9442** ^These interfaces are only available if SQLite is compiled using the 9443** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 9444** 9445** ^The [sqlite3_preupdate_hook()] interface registers a callback function 9446** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 9447** on a database table. 9448** ^At most one preupdate hook may be registered at a time on a single 9449** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 9450** the previous setting. 9451** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 9452** with a NULL pointer as the second parameter. 9453** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 9454** the first parameter to callbacks. 9455** 9456** ^The preupdate hook only fires for changes to real database tables; the 9457** preupdate hook is not invoked for changes to [virtual tables] or to 9458** system tables like sqlite_sequence or sqlite_stat1. 9459** 9460** ^The second parameter to the preupdate callback is a pointer to 9461** the [database connection] that registered the preupdate hook. 9462** ^The third parameter to the preupdate callback is one of the constants 9463** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 9464** kind of update operation that is about to occur. 9465** ^(The fourth parameter to the preupdate callback is the name of the 9466** database within the database connection that is being modified. This 9467** will be "main" for the main database or "temp" for TEMP tables or 9468** the name given after the AS keyword in the [ATTACH] statement for attached 9469** databases.)^ 9470** ^The fifth parameter to the preupdate callback is the name of the 9471** table that is being modified. 9472** 9473** For an UPDATE or DELETE operation on a [rowid table], the sixth 9474** parameter passed to the preupdate callback is the initial [rowid] of the 9475** row being modified or deleted. For an INSERT operation on a rowid table, 9476** or any operation on a WITHOUT ROWID table, the value of the sixth 9477** parameter is undefined. For an INSERT or UPDATE on a rowid table the 9478** seventh parameter is the final rowid value of the row being inserted 9479** or updated. The value of the seventh parameter passed to the callback 9480** function is not defined for operations on WITHOUT ROWID tables, or for 9481** DELETE operations on rowid tables. 9482** 9483** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 9484** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 9485** provide additional information about a preupdate event. These routines 9486** may only be called from within a preupdate callback. Invoking any of 9487** these routines from outside of a preupdate callback or with a 9488** [database connection] pointer that is different from the one supplied 9489** to the preupdate callback results in undefined and probably undesirable 9490** behavior. 9491** 9492** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 9493** in the row that is being inserted, updated, or deleted. 9494** 9495** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 9496** a [protected sqlite3_value] that contains the value of the Nth column of 9497** the table row before it is updated. The N parameter must be between 0 9498** and one less than the number of columns or the behavior will be 9499** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 9500** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 9501** behavior is undefined. The [sqlite3_value] that P points to 9502** will be destroyed when the preupdate callback returns. 9503** 9504** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 9505** a [protected sqlite3_value] that contains the value of the Nth column of 9506** the table row after it is updated. The N parameter must be between 0 9507** and one less than the number of columns or the behavior will be 9508** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 9509** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 9510** behavior is undefined. The [sqlite3_value] that P points to 9511** will be destroyed when the preupdate callback returns. 9512** 9513** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 9514** callback was invoked as a result of a direct insert, update, or delete 9515** operation; or 1 for inserts, updates, or deletes invoked by top-level 9516** triggers; or 2 for changes resulting from triggers called by top-level 9517** triggers; and so forth. 9518** 9519** See also: [sqlite3_update_hook()] 9520*/ 9521#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 9522void *sqlite3_preupdate_hook( 9523 sqlite3 *db, 9524 void(*xPreUpdate)( 9525 void *pCtx, /* Copy of third arg to preupdate_hook() */ 9526 sqlite3 *db, /* Database handle */ 9527 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 9528 char const *zDb, /* Database name */ 9529 char const *zName, /* Table name */ 9530 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 9531 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 9532 ), 9533 void* 9534); 9535int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 9536int sqlite3_preupdate_count(sqlite3 *); 9537int sqlite3_preupdate_depth(sqlite3 *); 9538int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 9539#endif 9540 9541/* 9542** CAPI3REF: Low-level system error code 9543** METHOD: sqlite3 9544** 9545** ^Attempt to return the underlying operating system error code or error 9546** number that caused the most recent I/O error or failure to open a file. 9547** The return value is OS-dependent. For example, on unix systems, after 9548** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 9549** called to get back the underlying "errno" that caused the problem, such 9550** as ENOSPC, EAUTH, EISDIR, and so forth. 9551*/ 9552int sqlite3_system_errno(sqlite3*); 9553 9554/* 9555** CAPI3REF: Database Snapshot 9556** KEYWORDS: {snapshot} {sqlite3_snapshot} 9557** 9558** An instance of the snapshot object records the state of a [WAL mode] 9559** database for some specific point in history. 9560** 9561** In [WAL mode], multiple [database connections] that are open on the 9562** same database file can each be reading a different historical version 9563** of the database file. When a [database connection] begins a read 9564** transaction, that connection sees an unchanging copy of the database 9565** as it existed for the point in time when the transaction first started. 9566** Subsequent changes to the database from other connections are not seen 9567** by the reader until a new read transaction is started. 9568** 9569** The sqlite3_snapshot object records state information about an historical 9570** version of the database file so that it is possible to later open a new read 9571** transaction that sees that historical version of the database rather than 9572** the most recent version. 9573*/ 9574typedef struct sqlite3_snapshot { 9575 unsigned char hidden[48]; 9576} sqlite3_snapshot; 9577 9578/* 9579** CAPI3REF: Record A Database Snapshot 9580** CONSTRUCTOR: sqlite3_snapshot 9581** 9582** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 9583** new [sqlite3_snapshot] object that records the current state of 9584** schema S in database connection D. ^On success, the 9585** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 9586** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 9587** If there is not already a read-transaction open on schema S when 9588** this function is called, one is opened automatically. 9589** 9590** The following must be true for this function to succeed. If any of 9591** the following statements are false when sqlite3_snapshot_get() is 9592** called, SQLITE_ERROR is returned. The final value of *P is undefined 9593** in this case. 9594** 9595** <ul> 9596** <li> The database handle must not be in [autocommit mode]. 9597** 9598** <li> Schema S of [database connection] D must be a [WAL mode] database. 9599** 9600** <li> There must not be a write transaction open on schema S of database 9601** connection D. 9602** 9603** <li> One or more transactions must have been written to the current wal 9604** file since it was created on disk (by any connection). This means 9605** that a snapshot cannot be taken on a wal mode database with no wal 9606** file immediately after it is first opened. At least one transaction 9607** must be written to it first. 9608** </ul> 9609** 9610** This function may also return SQLITE_NOMEM. If it is called with the 9611** database handle in autocommit mode but fails for some other reason, 9612** whether or not a read transaction is opened on schema S is undefined. 9613** 9614** The [sqlite3_snapshot] object returned from a successful call to 9615** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 9616** to avoid a memory leak. 9617** 9618** The [sqlite3_snapshot_get()] interface is only available when the 9619** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9620*/ 9621SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 9622 sqlite3 *db, 9623 const char *zSchema, 9624 sqlite3_snapshot **ppSnapshot 9625); 9626 9627/* 9628** CAPI3REF: Start a read transaction on an historical snapshot 9629** METHOD: sqlite3_snapshot 9630** 9631** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read 9632** transaction or upgrades an existing one for schema S of 9633** [database connection] D such that the read transaction refers to 9634** historical [snapshot] P, rather than the most recent change to the 9635** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK 9636** on success or an appropriate [error code] if it fails. 9637** 9638** ^In order to succeed, the database connection must not be in 9639** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there 9640** is already a read transaction open on schema S, then the database handle 9641** must have no active statements (SELECT statements that have been passed 9642** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()). 9643** SQLITE_ERROR is returned if either of these conditions is violated, or 9644** if schema S does not exist, or if the snapshot object is invalid. 9645** 9646** ^A call to sqlite3_snapshot_open() will fail to open if the specified 9647** snapshot has been overwritten by a [checkpoint]. In this case 9648** SQLITE_ERROR_SNAPSHOT is returned. 9649** 9650** If there is already a read transaction open when this function is 9651** invoked, then the same read transaction remains open (on the same 9652** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT 9653** is returned. If another error code - for example SQLITE_PROTOCOL or an 9654** SQLITE_IOERR error code - is returned, then the final state of the 9655** read transaction is undefined. If SQLITE_OK is returned, then the 9656** read transaction is now open on database snapshot P. 9657** 9658** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 9659** database connection D does not know that the database file for 9660** schema S is in [WAL mode]. A database connection might not know 9661** that the database file is in [WAL mode] if there has been no prior 9662** I/O on that database connection, or if the database entered [WAL mode] 9663** after the most recent I/O on the database connection.)^ 9664** (Hint: Run "[PRAGMA application_id]" against a newly opened 9665** database connection in order to make it ready to use snapshots.) 9666** 9667** The [sqlite3_snapshot_open()] interface is only available when the 9668** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9669*/ 9670SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 9671 sqlite3 *db, 9672 const char *zSchema, 9673 sqlite3_snapshot *pSnapshot 9674); 9675 9676/* 9677** CAPI3REF: Destroy a snapshot 9678** DESTRUCTOR: sqlite3_snapshot 9679** 9680** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 9681** The application must eventually free every [sqlite3_snapshot] object 9682** using this routine to avoid a memory leak. 9683** 9684** The [sqlite3_snapshot_free()] interface is only available when the 9685** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9686*/ 9687SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 9688 9689/* 9690** CAPI3REF: Compare the ages of two snapshot handles. 9691** METHOD: sqlite3_snapshot 9692** 9693** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 9694** of two valid snapshot handles. 9695** 9696** If the two snapshot handles are not associated with the same database 9697** file, the result of the comparison is undefined. 9698** 9699** Additionally, the result of the comparison is only valid if both of the 9700** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 9701** last time the wal file was deleted. The wal file is deleted when the 9702** database is changed back to rollback mode or when the number of database 9703** clients drops to zero. If either snapshot handle was obtained before the 9704** wal file was last deleted, the value returned by this function 9705** is undefined. 9706** 9707** Otherwise, this API returns a negative value if P1 refers to an older 9708** snapshot than P2, zero if the two handles refer to the same database 9709** snapshot, and a positive value if P1 is a newer snapshot than P2. 9710** 9711** This interface is only available if SQLite is compiled with the 9712** [SQLITE_ENABLE_SNAPSHOT] option. 9713*/ 9714SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 9715 sqlite3_snapshot *p1, 9716 sqlite3_snapshot *p2 9717); 9718 9719/* 9720** CAPI3REF: Recover snapshots from a wal file 9721** METHOD: sqlite3_snapshot 9722** 9723** If a [WAL file] remains on disk after all database connections close 9724** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control] 9725** or because the last process to have the database opened exited without 9726** calling [sqlite3_close()]) and a new connection is subsequently opened 9727** on that database and [WAL file], the [sqlite3_snapshot_open()] interface 9728** will only be able to open the last transaction added to the WAL file 9729** even though the WAL file contains other valid transactions. 9730** 9731** This function attempts to scan the WAL file associated with database zDb 9732** of database handle db and make all valid snapshots available to 9733** sqlite3_snapshot_open(). It is an error if there is already a read 9734** transaction open on the database, or if the database is not a WAL mode 9735** database. 9736** 9737** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 9738** 9739** This interface is only available if SQLite is compiled with the 9740** [SQLITE_ENABLE_SNAPSHOT] option. 9741*/ 9742SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 9743 9744/* 9745** CAPI3REF: Serialize a database 9746** 9747** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 9748** that is a serialization of the S database on [database connection] D. 9749** If P is not a NULL pointer, then the size of the database in bytes 9750** is written into *P. 9751** 9752** For an ordinary on-disk database file, the serialization is just a 9753** copy of the disk file. For an in-memory database or a "TEMP" database, 9754** the serialization is the same sequence of bytes which would be written 9755** to disk if that database where backed up to disk. 9756** 9757** The usual case is that sqlite3_serialize() copies the serialization of 9758** the database into memory obtained from [sqlite3_malloc64()] and returns 9759** a pointer to that memory. The caller is responsible for freeing the 9760** returned value to avoid a memory leak. However, if the F argument 9761** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 9762** are made, and the sqlite3_serialize() function will return a pointer 9763** to the contiguous memory representation of the database that SQLite 9764** is currently using for that database, or NULL if the no such contiguous 9765** memory representation of the database exists. A contiguous memory 9766** representation of the database will usually only exist if there has 9767** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 9768** values of D and S. 9769** The size of the database is written into *P even if the 9770** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy 9771** of the database exists. 9772** 9773** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 9774** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 9775** allocation error occurs. 9776** 9777** This interface is only available if SQLite is compiled with the 9778** [SQLITE_ENABLE_DESERIALIZE] option. 9779*/ 9780unsigned char *sqlite3_serialize( 9781 sqlite3 *db, /* The database connection */ 9782 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 9783 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 9784 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 9785); 9786 9787/* 9788** CAPI3REF: Flags for sqlite3_serialize 9789** 9790** Zero or more of the following constants can be OR-ed together for 9791** the F argument to [sqlite3_serialize(D,S,P,F)]. 9792** 9793** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 9794** a pointer to contiguous in-memory database that it is currently using, 9795** without making a copy of the database. If SQLite is not currently using 9796** a contiguous in-memory database, then this option causes 9797** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 9798** using a contiguous in-memory database if it has been initialized by a 9799** prior call to [sqlite3_deserialize()]. 9800*/ 9801#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 9802 9803/* 9804** CAPI3REF: Deserialize a database 9805** 9806** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 9807** [database connection] D to disconnect from database S and then 9808** reopen S as an in-memory database based on the serialization contained 9809** in P. The serialized database P is N bytes in size. M is the size of 9810** the buffer P, which might be larger than N. If M is larger than N, and 9811** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 9812** permitted to add content to the in-memory database as long as the total 9813** size does not exceed M bytes. 9814** 9815** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 9816** invoke sqlite3_free() on the serialization buffer when the database 9817** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 9818** SQLite will try to increase the buffer size using sqlite3_realloc64() 9819** if writes on the database cause it to grow larger than M bytes. 9820** 9821** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 9822** database is currently in a read transaction or is involved in a backup 9823** operation. 9824** 9825** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 9826** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 9827** [sqlite3_free()] is invoked on argument P prior to returning. 9828** 9829** This interface is only available if SQLite is compiled with the 9830** [SQLITE_ENABLE_DESERIALIZE] option. 9831*/ 9832int sqlite3_deserialize( 9833 sqlite3 *db, /* The database connection */ 9834 const char *zSchema, /* Which DB to reopen with the deserialization */ 9835 unsigned char *pData, /* The serialized database content */ 9836 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 9837 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 9838 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 9839); 9840 9841/* 9842** CAPI3REF: Flags for sqlite3_deserialize() 9843** 9844** The following are allowed values for 6th argument (the F argument) to 9845** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 9846** 9847** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 9848** in the P argument is held in memory obtained from [sqlite3_malloc64()] 9849** and that SQLite should take ownership of this memory and automatically 9850** free it when it has finished using it. Without this flag, the caller 9851** is responsible for freeing any dynamically allocated memory. 9852** 9853** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 9854** grow the size of the database using calls to [sqlite3_realloc64()]. This 9855** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 9856** Without this flag, the deserialized database cannot increase in size beyond 9857** the number of bytes specified by the M parameter. 9858** 9859** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 9860** should be treated as read-only. 9861*/ 9862#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 9863#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 9864#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 9865 9866/* 9867** Undo the hack that converts floating point types to integer for 9868** builds on processors without floating point support. 9869*/ 9870#ifdef SQLITE_OMIT_FLOATING_POINT 9871# undef double 9872#endif 9873 9874#ifdef __cplusplus 9875} /* End of the 'extern "C"' block */ 9876#endif 9877#endif /* SQLITE3_H */ 9878