1/* 2** 2001-09-15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are supposed to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef SQLITE3_H 34#define SQLITE3_H 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_APICALL 58# define SQLITE_APICALL 59#endif 60#ifndef SQLITE_STDCALL 61# define SQLITE_STDCALL SQLITE_APICALL 62#endif 63#ifndef SQLITE_CALLBACK 64# define SQLITE_CALLBACK 65#endif 66#ifndef SQLITE_SYSAPI 67# define SQLITE_SYSAPI 68#endif 69 70/* 71** These no-op macros are used in front of interfaces to mark those 72** interfaces as either deprecated or experimental. New applications 73** should not use deprecated interfaces - they are supported for backwards 74** compatibility only. Application writers should be aware that 75** experimental interfaces are subject to change in point releases. 76** 77** These macros used to resolve to various kinds of compiler magic that 78** would generate warning messages when they were used. But that 79** compiler magic ended up generating such a flurry of bug reports 80** that we have taken it all out and gone back to using simple 81** noop macros. 82*/ 83#define SQLITE_DEPRECATED 84#define SQLITE_EXPERIMENTAL 85 86/* 87** Ensure these symbols were not defined by some previous header file. 88*/ 89#ifdef SQLITE_VERSION 90# undef SQLITE_VERSION 91#endif 92#ifdef SQLITE_VERSION_NUMBER 93# undef SQLITE_VERSION_NUMBER 94#endif 95 96/* 97** CAPI3REF: Compile-Time Library Version Numbers 98** 99** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 100** evaluates to a string literal that is the SQLite version in the 101** format "X.Y.Z" where X is the major version number (always 3 for 102** SQLite3) and Y is the minor version number and Z is the release number.)^ 103** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 104** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 105** numbers used in [SQLITE_VERSION].)^ 106** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 107** be larger than the release from which it is derived. Either Y will 108** be held constant and Z will be incremented or else Y will be incremented 109** and Z will be reset to zero. 110** 111** Since [version 3.6.18] ([dateof:3.6.18]), 112** SQLite source code has been stored in the 113** <a href="http://www.fossil-scm.org/">Fossil configuration management 114** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 115** a string which identifies a particular check-in of SQLite 116** within its configuration management system. ^The SQLITE_SOURCE_ID 117** string contains the date and time of the check-in (UTC) and a SHA1 118** or SHA3-256 hash of the entire source tree. If the source code has 119** been edited in any way since it was last checked in, then the last 120** four hexadecimal digits of the hash may be modified. 121** 122** See also: [sqlite3_libversion()], 123** [sqlite3_libversion_number()], [sqlite3_sourceid()], 124** [sqlite_version()] and [sqlite_source_id()]. 125*/ 126#define SQLITE_VERSION "--VERS--" 127#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 128#define SQLITE_SOURCE_ID "--SOURCE-ID--" 129 130/* 131** CAPI3REF: Run-Time Library Version Numbers 132** KEYWORDS: sqlite3_version sqlite3_sourceid 133** 134** These interfaces provide the same information as the [SQLITE_VERSION], 135** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 136** but are associated with the library instead of the header file. ^(Cautious 137** programmers might include assert() statements in their application to 138** verify that values returned by these interfaces match the macros in 139** the header, and thus ensure that the application is 140** compiled with matching library and header files. 141** 142** <blockquote><pre> 143** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 144** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 ); 145** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 146** </pre></blockquote>)^ 147** 148** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 149** macro. ^The sqlite3_libversion() function returns a pointer to the 150** to the sqlite3_version[] string constant. The sqlite3_libversion() 151** function is provided for use in DLLs since DLL users usually do not have 152** direct access to string constants within the DLL. ^The 153** sqlite3_libversion_number() function returns an integer equal to 154** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns 155** a pointer to a string constant whose value is the same as the 156** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built 157** using an edited copy of [the amalgamation], then the last four characters 158** of the hash might be different from [SQLITE_SOURCE_ID].)^ 159** 160** See also: [sqlite_version()] and [sqlite_source_id()]. 161*/ 162SQLITE_EXTERN const char sqlite3_version[]; 163const char *sqlite3_libversion(void); 164const char *sqlite3_sourceid(void); 165int sqlite3_libversion_number(void); 166 167/* 168** CAPI3REF: Run-Time Library Compilation Options Diagnostics 169** 170** ^The sqlite3_compileoption_used() function returns 0 or 1 171** indicating whether the specified option was defined at 172** compile time. ^The SQLITE_ prefix may be omitted from the 173** option name passed to sqlite3_compileoption_used(). 174** 175** ^The sqlite3_compileoption_get() function allows iterating 176** over the list of options that were defined at compile time by 177** returning the N-th compile time option string. ^If N is out of range, 178** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 179** prefix is omitted from any strings returned by 180** sqlite3_compileoption_get(). 181** 182** ^Support for the diagnostic functions sqlite3_compileoption_used() 183** and sqlite3_compileoption_get() may be omitted by specifying the 184** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 185** 186** See also: SQL functions [sqlite_compileoption_used()] and 187** [sqlite_compileoption_get()] and the [compile_options pragma]. 188*/ 189#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 190int sqlite3_compileoption_used(const char *zOptName); 191const char *sqlite3_compileoption_get(int N); 192#else 193# define sqlite3_compileoption_used(X) 0 194# define sqlite3_compileoption_get(X) ((void*)0) 195#endif 196 197/* 198** CAPI3REF: Test To See If The Library Is Threadsafe 199** 200** ^The sqlite3_threadsafe() function returns zero if and only if 201** SQLite was compiled with mutexing code omitted due to the 202** [SQLITE_THREADSAFE] compile-time option being set to 0. 203** 204** SQLite can be compiled with or without mutexes. When 205** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 206** are enabled and SQLite is threadsafe. When the 207** [SQLITE_THREADSAFE] macro is 0, 208** the mutexes are omitted. Without the mutexes, it is not safe 209** to use SQLite concurrently from more than one thread. 210** 211** Enabling mutexes incurs a measurable performance penalty. 212** So if speed is of utmost importance, it makes sense to disable 213** the mutexes. But for maximum safety, mutexes should be enabled. 214** ^The default behavior is for mutexes to be enabled. 215** 216** This interface can be used by an application to make sure that the 217** version of SQLite that it is linking against was compiled with 218** the desired setting of the [SQLITE_THREADSAFE] macro. 219** 220** This interface only reports on the compile-time mutex setting 221** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 222** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 223** can be fully or partially disabled using a call to [sqlite3_config()] 224** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 225** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 226** sqlite3_threadsafe() function shows only the compile-time setting of 227** thread safety, not any run-time changes to that setting made by 228** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 229** is unchanged by calls to sqlite3_config().)^ 230** 231** See the [threading mode] documentation for additional information. 232*/ 233int sqlite3_threadsafe(void); 234 235/* 236** CAPI3REF: Database Connection Handle 237** KEYWORDS: {database connection} {database connections} 238** 239** Each open SQLite database is represented by a pointer to an instance of 240** the opaque structure named "sqlite3". It is useful to think of an sqlite3 241** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 242** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 243** and [sqlite3_close_v2()] are its destructors. There are many other 244** interfaces (such as 245** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 246** [sqlite3_busy_timeout()] to name but three) that are methods on an 247** sqlite3 object. 248*/ 249typedef struct sqlite3 sqlite3; 250 251/* 252** CAPI3REF: 64-Bit Integer Types 253** KEYWORDS: sqlite_int64 sqlite_uint64 254** 255** Because there is no cross-platform way to specify 64-bit integer types 256** SQLite includes typedefs for 64-bit signed and unsigned integers. 257** 258** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 259** The sqlite_int64 and sqlite_uint64 types are supported for backwards 260** compatibility only. 261** 262** ^The sqlite3_int64 and sqlite_int64 types can store integer values 263** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 264** sqlite3_uint64 and sqlite_uint64 types can store integer values 265** between 0 and +18446744073709551615 inclusive. 266*/ 267#ifdef SQLITE_INT64_TYPE 268 typedef SQLITE_INT64_TYPE sqlite_int64; 269# ifdef SQLITE_UINT64_TYPE 270 typedef SQLITE_UINT64_TYPE sqlite_uint64; 271# else 272 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 273# endif 274#elif defined(_MSC_VER) || defined(__BORLANDC__) 275 typedef __int64 sqlite_int64; 276 typedef unsigned __int64 sqlite_uint64; 277#else 278 typedef long long int sqlite_int64; 279 typedef unsigned long long int sqlite_uint64; 280#endif 281typedef sqlite_int64 sqlite3_int64; 282typedef sqlite_uint64 sqlite3_uint64; 283 284/* 285** If compiling for a processor that lacks floating point support, 286** substitute integer for floating-point. 287*/ 288#ifdef SQLITE_OMIT_FLOATING_POINT 289# define double sqlite3_int64 290#endif 291 292/* 293** CAPI3REF: Closing A Database Connection 294** DESTRUCTOR: sqlite3 295** 296** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 297** for the [sqlite3] object. 298** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 299** the [sqlite3] object is successfully destroyed and all associated 300** resources are deallocated. 301** 302** Ideally, applications should [sqlite3_finalize | finalize] all 303** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and 304** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 305** with the [sqlite3] object prior to attempting to close the object. 306** ^If the database connection is associated with unfinalized prepared 307** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then 308** sqlite3_close() will leave the database connection open and return 309** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared 310** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups, 311** it returns [SQLITE_OK] regardless, but instead of deallocating the database 312** connection immediately, it marks the database connection as an unusable 313** "zombie" and makes arrangements to automatically deallocate the database 314** connection after all prepared statements are finalized, all BLOB handles 315** are closed, and all backups have finished. The sqlite3_close_v2() interface 316** is intended for use with host languages that are garbage collected, and 317** where the order in which destructors are called is arbitrary. 318** 319** ^If an [sqlite3] object is destroyed while a transaction is open, 320** the transaction is automatically rolled back. 321** 322** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 323** must be either a NULL 324** pointer or an [sqlite3] object pointer obtained 325** from [sqlite3_open()], [sqlite3_open16()], or 326** [sqlite3_open_v2()], and not previously closed. 327** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 328** argument is a harmless no-op. 329*/ 330int sqlite3_close(sqlite3*); 331int sqlite3_close_v2(sqlite3*); 332 333/* 334** The type for a callback function. 335** This is legacy and deprecated. It is included for historical 336** compatibility and is not documented. 337*/ 338typedef int (*sqlite3_callback)(void*,int,char**, char**); 339 340/* 341** CAPI3REF: One-Step Query Execution Interface 342** METHOD: sqlite3 343** 344** The sqlite3_exec() interface is a convenience wrapper around 345** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 346** that allows an application to run multiple statements of SQL 347** without having to use a lot of C code. 348** 349** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 350** semicolon-separate SQL statements passed into its 2nd argument, 351** in the context of the [database connection] passed in as its 1st 352** argument. ^If the callback function of the 3rd argument to 353** sqlite3_exec() is not NULL, then it is invoked for each result row 354** coming out of the evaluated SQL statements. ^The 4th argument to 355** sqlite3_exec() is relayed through to the 1st argument of each 356** callback invocation. ^If the callback pointer to sqlite3_exec() 357** is NULL, then no callback is ever invoked and result rows are 358** ignored. 359** 360** ^If an error occurs while evaluating the SQL statements passed into 361** sqlite3_exec(), then execution of the current statement stops and 362** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 363** is not NULL then any error message is written into memory obtained 364** from [sqlite3_malloc()] and passed back through the 5th parameter. 365** To avoid memory leaks, the application should invoke [sqlite3_free()] 366** on error message strings returned through the 5th parameter of 367** sqlite3_exec() after the error message string is no longer needed. 368** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 369** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 370** NULL before returning. 371** 372** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 373** routine returns SQLITE_ABORT without invoking the callback again and 374** without running any subsequent SQL statements. 375** 376** ^The 2nd argument to the sqlite3_exec() callback function is the 377** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 378** callback is an array of pointers to strings obtained as if from 379** [sqlite3_column_text()], one for each column. ^If an element of a 380** result row is NULL then the corresponding string pointer for the 381** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 382** sqlite3_exec() callback is an array of pointers to strings where each 383** entry represents the name of corresponding result column as obtained 384** from [sqlite3_column_name()]. 385** 386** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 387** to an empty string, or a pointer that contains only whitespace and/or 388** SQL comments, then no SQL statements are evaluated and the database 389** is not changed. 390** 391** Restrictions: 392** 393** <ul> 394** <li> The application must ensure that the 1st parameter to sqlite3_exec() 395** is a valid and open [database connection]. 396** <li> The application must not close the [database connection] specified by 397** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 398** <li> The application must not modify the SQL statement text passed into 399** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 400** </ul> 401*/ 402int sqlite3_exec( 403 sqlite3*, /* An open database */ 404 const char *sql, /* SQL to be evaluated */ 405 int (*callback)(void*,int,char**,char**), /* Callback function */ 406 void *, /* 1st argument to callback */ 407 char **errmsg /* Error msg written here */ 408); 409 410/* 411** CAPI3REF: Result Codes 412** KEYWORDS: {result code definitions} 413** 414** Many SQLite functions return an integer result code from the set shown 415** here in order to indicate success or failure. 416** 417** New error codes may be added in future versions of SQLite. 418** 419** See also: [extended result code definitions] 420*/ 421#define SQLITE_OK 0 /* Successful result */ 422/* beginning-of-error-codes */ 423#define SQLITE_ERROR 1 /* Generic error */ 424#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 425#define SQLITE_PERM 3 /* Access permission denied */ 426#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 427#define SQLITE_BUSY 5 /* The database file is locked */ 428#define SQLITE_LOCKED 6 /* A table in the database is locked */ 429#define SQLITE_NOMEM 7 /* A malloc() failed */ 430#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 431#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 432#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 433#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 434#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 435#define SQLITE_FULL 13 /* Insertion failed because database is full */ 436#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 437#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 438#define SQLITE_EMPTY 16 /* Internal use only */ 439#define SQLITE_SCHEMA 17 /* The database schema changed */ 440#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 441#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 442#define SQLITE_MISMATCH 20 /* Data type mismatch */ 443#define SQLITE_MISUSE 21 /* Library used incorrectly */ 444#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 445#define SQLITE_AUTH 23 /* Authorization denied */ 446#define SQLITE_FORMAT 24 /* Not used */ 447#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 448#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 449#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 450#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 451#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 452#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 453/* end-of-error-codes */ 454 455/* 456** CAPI3REF: Extended Result Codes 457** KEYWORDS: {extended result code definitions} 458** 459** In its default configuration, SQLite API routines return one of 30 integer 460** [result codes]. However, experience has shown that many of 461** these result codes are too coarse-grained. They do not provide as 462** much information about problems as programmers might like. In an effort to 463** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 464** and later) include 465** support for additional result codes that provide more detailed information 466** about errors. These [extended result codes] are enabled or disabled 467** on a per database connection basis using the 468** [sqlite3_extended_result_codes()] API. Or, the extended code for 469** the most recent error can be obtained using 470** [sqlite3_extended_errcode()]. 471*/ 472#define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8)) 473#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8)) 474#define SQLITE_ERROR_SNAPSHOT (SQLITE_ERROR | (3<<8)) 475#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 476#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 477#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 478#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 479#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 480#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 481#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 482#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 483#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 484#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 485#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 486#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 487#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 488#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 489#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 490#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 491#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 492#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 493#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 494#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 495#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 496#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 497#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 498#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 499#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 500#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 501#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 502#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 503#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 504#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 505#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 506#define SQLITE_IOERR_DATA (SQLITE_IOERR | (32<<8)) 507#define SQLITE_IOERR_CORRUPTFS (SQLITE_IOERR | (33<<8)) 508#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 509#define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8)) 510#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 511#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 512#define SQLITE_BUSY_TIMEOUT (SQLITE_BUSY | (3<<8)) 513#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 514#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 515#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 516#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 517#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */ 518#define SQLITE_CANTOPEN_SYMLINK (SQLITE_CANTOPEN | (6<<8)) 519#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 520#define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8)) 521#define SQLITE_CORRUPT_INDEX (SQLITE_CORRUPT | (3<<8)) 522#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 523#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 524#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 525#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 526#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8)) 527#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8)) 528#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 529#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 530#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 531#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 532#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 533#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 534#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 535#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 536#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 537#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 538#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 539#define SQLITE_CONSTRAINT_PINNED (SQLITE_CONSTRAINT |(11<<8)) 540#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 541#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 542#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 543#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 544#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 545#define SQLITE_OK_SYMLINK (SQLITE_OK | (2<<8)) 546 547/* 548** CAPI3REF: Flags For File Open Operations 549** 550** These bit values are intended for use in the 551** 3rd parameter to the [sqlite3_open_v2()] interface and 552** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 553*/ 554#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 555#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 556#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 557#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 558#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 559#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 560#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 561#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 562#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 563#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 564#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 565#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 566#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 567#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 568#define SQLITE_OPEN_SUPER_JOURNAL 0x00004000 /* VFS only */ 569#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 570#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 571#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 572#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 573#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 574#define SQLITE_OPEN_NOFOLLOW 0x01000000 /* Ok for sqlite3_open_v2() */ 575 576/* Reserved: 0x00F00000 */ 577/* Legacy compatibility: */ 578#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 579 580 581/* 582** CAPI3REF: Device Characteristics 583** 584** The xDeviceCharacteristics method of the [sqlite3_io_methods] 585** object returns an integer which is a vector of these 586** bit values expressing I/O characteristics of the mass storage 587** device that holds the file that the [sqlite3_io_methods] 588** refers to. 589** 590** The SQLITE_IOCAP_ATOMIC property means that all writes of 591** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 592** mean that writes of blocks that are nnn bytes in size and 593** are aligned to an address which is an integer multiple of 594** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 595** that when data is appended to a file, the data is appended 596** first then the size of the file is extended, never the other 597** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 598** information is written to disk in the same order as calls 599** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 600** after reboot following a crash or power loss, the only bytes in a 601** file that were written at the application level might have changed 602** and that adjacent bytes, even bytes within the same sector are 603** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 604** flag indicates that a file cannot be deleted when open. The 605** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 606** read-only media and cannot be changed even by processes with 607** elevated privileges. 608** 609** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 610** filesystem supports doing multiple write operations atomically when those 611** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 612** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 613*/ 614#define SQLITE_IOCAP_ATOMIC 0x00000001 615#define SQLITE_IOCAP_ATOMIC512 0x00000002 616#define SQLITE_IOCAP_ATOMIC1K 0x00000004 617#define SQLITE_IOCAP_ATOMIC2K 0x00000008 618#define SQLITE_IOCAP_ATOMIC4K 0x00000010 619#define SQLITE_IOCAP_ATOMIC8K 0x00000020 620#define SQLITE_IOCAP_ATOMIC16K 0x00000040 621#define SQLITE_IOCAP_ATOMIC32K 0x00000080 622#define SQLITE_IOCAP_ATOMIC64K 0x00000100 623#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 624#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 625#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 626#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 627#define SQLITE_IOCAP_IMMUTABLE 0x00002000 628#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 629 630/* 631** CAPI3REF: File Locking Levels 632** 633** SQLite uses one of these integer values as the second 634** argument to calls it makes to the xLock() and xUnlock() methods 635** of an [sqlite3_io_methods] object. 636*/ 637#define SQLITE_LOCK_NONE 0 638#define SQLITE_LOCK_SHARED 1 639#define SQLITE_LOCK_RESERVED 2 640#define SQLITE_LOCK_PENDING 3 641#define SQLITE_LOCK_EXCLUSIVE 4 642 643/* 644** CAPI3REF: Synchronization Type Flags 645** 646** When SQLite invokes the xSync() method of an 647** [sqlite3_io_methods] object it uses a combination of 648** these integer values as the second argument. 649** 650** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 651** sync operation only needs to flush data to mass storage. Inode 652** information need not be flushed. If the lower four bits of the flag 653** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 654** If the lower four bits equal SQLITE_SYNC_FULL, that means 655** to use Mac OS X style fullsync instead of fsync(). 656** 657** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 658** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 659** settings. The [synchronous pragma] determines when calls to the 660** xSync VFS method occur and applies uniformly across all platforms. 661** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 662** energetic or rigorous or forceful the sync operations are and 663** only make a difference on Mac OSX for the default SQLite code. 664** (Third-party VFS implementations might also make the distinction 665** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 666** operating systems natively supported by SQLite, only Mac OSX 667** cares about the difference.) 668*/ 669#define SQLITE_SYNC_NORMAL 0x00002 670#define SQLITE_SYNC_FULL 0x00003 671#define SQLITE_SYNC_DATAONLY 0x00010 672 673/* 674** CAPI3REF: OS Interface Open File Handle 675** 676** An [sqlite3_file] object represents an open file in the 677** [sqlite3_vfs | OS interface layer]. Individual OS interface 678** implementations will 679** want to subclass this object by appending additional fields 680** for their own use. The pMethods entry is a pointer to an 681** [sqlite3_io_methods] object that defines methods for performing 682** I/O operations on the open file. 683*/ 684typedef struct sqlite3_file sqlite3_file; 685struct sqlite3_file { 686 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 687}; 688 689/* 690** CAPI3REF: OS Interface File Virtual Methods Object 691** 692** Every file opened by the [sqlite3_vfs.xOpen] method populates an 693** [sqlite3_file] object (or, more commonly, a subclass of the 694** [sqlite3_file] object) with a pointer to an instance of this object. 695** This object defines the methods used to perform various operations 696** against the open file represented by the [sqlite3_file] object. 697** 698** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 699** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 700** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 701** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 702** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 703** to NULL. 704** 705** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 706** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 707** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 708** flag may be ORed in to indicate that only the data of the file 709** and not its inode needs to be synced. 710** 711** The integer values to xLock() and xUnlock() are one of 712** <ul> 713** <li> [SQLITE_LOCK_NONE], 714** <li> [SQLITE_LOCK_SHARED], 715** <li> [SQLITE_LOCK_RESERVED], 716** <li> [SQLITE_LOCK_PENDING], or 717** <li> [SQLITE_LOCK_EXCLUSIVE]. 718** </ul> 719** xLock() increases the lock. xUnlock() decreases the lock. 720** The xCheckReservedLock() method checks whether any database connection, 721** either in this process or in some other process, is holding a RESERVED, 722** PENDING, or EXCLUSIVE lock on the file. It returns true 723** if such a lock exists and false otherwise. 724** 725** The xFileControl() method is a generic interface that allows custom 726** VFS implementations to directly control an open file using the 727** [sqlite3_file_control()] interface. The second "op" argument is an 728** integer opcode. The third argument is a generic pointer intended to 729** point to a structure that may contain arguments or space in which to 730** write return values. Potential uses for xFileControl() might be 731** functions to enable blocking locks with timeouts, to change the 732** locking strategy (for example to use dot-file locks), to inquire 733** about the status of a lock, or to break stale locks. The SQLite 734** core reserves all opcodes less than 100 for its own use. 735** A [file control opcodes | list of opcodes] less than 100 is available. 736** Applications that define a custom xFileControl method should use opcodes 737** greater than 100 to avoid conflicts. VFS implementations should 738** return [SQLITE_NOTFOUND] for file control opcodes that they do not 739** recognize. 740** 741** The xSectorSize() method returns the sector size of the 742** device that underlies the file. The sector size is the 743** minimum write that can be performed without disturbing 744** other bytes in the file. The xDeviceCharacteristics() 745** method returns a bit vector describing behaviors of the 746** underlying device: 747** 748** <ul> 749** <li> [SQLITE_IOCAP_ATOMIC] 750** <li> [SQLITE_IOCAP_ATOMIC512] 751** <li> [SQLITE_IOCAP_ATOMIC1K] 752** <li> [SQLITE_IOCAP_ATOMIC2K] 753** <li> [SQLITE_IOCAP_ATOMIC4K] 754** <li> [SQLITE_IOCAP_ATOMIC8K] 755** <li> [SQLITE_IOCAP_ATOMIC16K] 756** <li> [SQLITE_IOCAP_ATOMIC32K] 757** <li> [SQLITE_IOCAP_ATOMIC64K] 758** <li> [SQLITE_IOCAP_SAFE_APPEND] 759** <li> [SQLITE_IOCAP_SEQUENTIAL] 760** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 761** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 762** <li> [SQLITE_IOCAP_IMMUTABLE] 763** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 764** </ul> 765** 766** The SQLITE_IOCAP_ATOMIC property means that all writes of 767** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 768** mean that writes of blocks that are nnn bytes in size and 769** are aligned to an address which is an integer multiple of 770** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 771** that when data is appended to a file, the data is appended 772** first then the size of the file is extended, never the other 773** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 774** information is written to disk in the same order as calls 775** to xWrite(). 776** 777** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 778** in the unread portions of the buffer with zeros. A VFS that 779** fails to zero-fill short reads might seem to work. However, 780** failure to zero-fill short reads will eventually lead to 781** database corruption. 782*/ 783typedef struct sqlite3_io_methods sqlite3_io_methods; 784struct sqlite3_io_methods { 785 int iVersion; 786 int (*xClose)(sqlite3_file*); 787 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 788 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 789 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 790 int (*xSync)(sqlite3_file*, int flags); 791 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 792 int (*xLock)(sqlite3_file*, int); 793 int (*xUnlock)(sqlite3_file*, int); 794 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 795 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 796 int (*xSectorSize)(sqlite3_file*); 797 int (*xDeviceCharacteristics)(sqlite3_file*); 798 /* Methods above are valid for version 1 */ 799 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 800 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 801 void (*xShmBarrier)(sqlite3_file*); 802 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 803 /* Methods above are valid for version 2 */ 804 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 805 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 806 /* Methods above are valid for version 3 */ 807 /* Additional methods may be added in future releases */ 808}; 809 810/* 811** CAPI3REF: Standard File Control Opcodes 812** KEYWORDS: {file control opcodes} {file control opcode} 813** 814** These integer constants are opcodes for the xFileControl method 815** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 816** interface. 817** 818** <ul> 819** <li>[[SQLITE_FCNTL_LOCKSTATE]] 820** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 821** opcode causes the xFileControl method to write the current state of 822** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 823** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 824** into an integer that the pArg argument points to. This capability 825** is used during testing and is only available when the SQLITE_TEST 826** compile-time option is used. 827** 828** <li>[[SQLITE_FCNTL_SIZE_HINT]] 829** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 830** layer a hint of how large the database file will grow to be during the 831** current transaction. This hint is not guaranteed to be accurate but it 832** is often close. The underlying VFS might choose to preallocate database 833** file space based on this hint in order to help writes to the database 834** file run faster. 835** 836** <li>[[SQLITE_FCNTL_SIZE_LIMIT]] 837** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that 838** implements [sqlite3_deserialize()] to set an upper bound on the size 839** of the in-memory database. The argument is a pointer to a [sqlite3_int64]. 840** If the integer pointed to is negative, then it is filled in with the 841** current limit. Otherwise the limit is set to the larger of the value 842** of the integer pointed to and the current database size. The integer 843** pointed to is set to the new limit. 844** 845** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 846** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 847** extends and truncates the database file in chunks of a size specified 848** by the user. The fourth argument to [sqlite3_file_control()] should 849** point to an integer (type int) containing the new chunk-size to use 850** for the nominated database. Allocating database file space in large 851** chunks (say 1MB at a time), may reduce file-system fragmentation and 852** improve performance on some systems. 853** 854** <li>[[SQLITE_FCNTL_FILE_POINTER]] 855** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 856** to the [sqlite3_file] object associated with a particular database 857** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 858** 859** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 860** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 861** to the [sqlite3_file] object associated with the journal file (either 862** the [rollback journal] or the [write-ahead log]) for a particular database 863** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 864** 865** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 866** No longer in use. 867** 868** <li>[[SQLITE_FCNTL_SYNC]] 869** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 870** sent to the VFS immediately before the xSync method is invoked on a 871** database file descriptor. Or, if the xSync method is not invoked 872** because the user has configured SQLite with 873** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 874** of the xSync method. In most cases, the pointer argument passed with 875** this file-control is NULL. However, if the database file is being synced 876** as part of a multi-database commit, the argument points to a nul-terminated 877** string containing the transactions super-journal file name. VFSes that 878** do not need this signal should silently ignore this opcode. Applications 879** should not call [sqlite3_file_control()] with this opcode as doing so may 880** disrupt the operation of the specialized VFSes that do require it. 881** 882** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 883** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 884** and sent to the VFS after a transaction has been committed immediately 885** but before the database is unlocked. VFSes that do not need this signal 886** should silently ignore this opcode. Applications should not call 887** [sqlite3_file_control()] with this opcode as doing so may disrupt the 888** operation of the specialized VFSes that do require it. 889** 890** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 891** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 892** retry counts and intervals for certain disk I/O operations for the 893** windows [VFS] in order to provide robustness in the presence of 894** anti-virus programs. By default, the windows VFS will retry file read, 895** file write, and file delete operations up to 10 times, with a delay 896** of 25 milliseconds before the first retry and with the delay increasing 897** by an additional 25 milliseconds with each subsequent retry. This 898** opcode allows these two values (10 retries and 25 milliseconds of delay) 899** to be adjusted. The values are changed for all database connections 900** within the same process. The argument is a pointer to an array of two 901** integers where the first integer is the new retry count and the second 902** integer is the delay. If either integer is negative, then the setting 903** is not changed but instead the prior value of that setting is written 904** into the array entry, allowing the current retry settings to be 905** interrogated. The zDbName parameter is ignored. 906** 907** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 908** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 909** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 910** write ahead log ([WAL file]) and shared memory 911** files used for transaction control 912** are automatically deleted when the latest connection to the database 913** closes. Setting persistent WAL mode causes those files to persist after 914** close. Persisting the files is useful when other processes that do not 915** have write permission on the directory containing the database file want 916** to read the database file, as the WAL and shared memory files must exist 917** in order for the database to be readable. The fourth parameter to 918** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 919** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 920** WAL mode. If the integer is -1, then it is overwritten with the current 921** WAL persistence setting. 922** 923** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 924** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 925** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 926** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 927** xDeviceCharacteristics methods. The fourth parameter to 928** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 929** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 930** mode. If the integer is -1, then it is overwritten with the current 931** zero-damage mode setting. 932** 933** <li>[[SQLITE_FCNTL_OVERWRITE]] 934** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 935** a write transaction to indicate that, unless it is rolled back for some 936** reason, the entire database file will be overwritten by the current 937** transaction. This is used by VACUUM operations. 938** 939** <li>[[SQLITE_FCNTL_VFSNAME]] 940** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 941** all [VFSes] in the VFS stack. The names are of all VFS shims and the 942** final bottom-level VFS are written into memory obtained from 943** [sqlite3_malloc()] and the result is stored in the char* variable 944** that the fourth parameter of [sqlite3_file_control()] points to. 945** The caller is responsible for freeing the memory when done. As with 946** all file-control actions, there is no guarantee that this will actually 947** do anything. Callers should initialize the char* variable to a NULL 948** pointer in case this file-control is not implemented. This file-control 949** is intended for diagnostic use only. 950** 951** <li>[[SQLITE_FCNTL_VFS_POINTER]] 952** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 953** [VFSes] currently in use. ^(The argument X in 954** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 955** of type "[sqlite3_vfs] **". This opcodes will set *X 956** to a pointer to the top-level VFS.)^ 957** ^When there are multiple VFS shims in the stack, this opcode finds the 958** upper-most shim only. 959** 960** <li>[[SQLITE_FCNTL_PRAGMA]] 961** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 962** file control is sent to the open [sqlite3_file] object corresponding 963** to the database file to which the pragma statement refers. ^The argument 964** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 965** pointers to strings (char**) in which the second element of the array 966** is the name of the pragma and the third element is the argument to the 967** pragma or NULL if the pragma has no argument. ^The handler for an 968** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 969** of the char** argument point to a string obtained from [sqlite3_mprintf()] 970** or the equivalent and that string will become the result of the pragma or 971** the error message if the pragma fails. ^If the 972** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 973** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 974** file control returns [SQLITE_OK], then the parser assumes that the 975** VFS has handled the PRAGMA itself and the parser generates a no-op 976** prepared statement if result string is NULL, or that returns a copy 977** of the result string if the string is non-NULL. 978** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 979** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 980** that the VFS encountered an error while handling the [PRAGMA] and the 981** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 982** file control occurs at the beginning of pragma statement analysis and so 983** it is able to override built-in [PRAGMA] statements. 984** 985** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 986** ^The [SQLITE_FCNTL_BUSYHANDLER] 987** file-control may be invoked by SQLite on the database file handle 988** shortly after it is opened in order to provide a custom VFS with access 989** to the connection's busy-handler callback. The argument is of type (void**) 990** - an array of two (void *) values. The first (void *) actually points 991** to a function of type (int (*)(void *)). In order to invoke the connection's 992** busy-handler, this function should be invoked with the second (void *) in 993** the array as the only argument. If it returns non-zero, then the operation 994** should be retried. If it returns zero, the custom VFS should abandon the 995** current operation. 996** 997** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 998** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 999** to have SQLite generate a 1000** temporary filename using the same algorithm that is followed to generate 1001** temporary filenames for TEMP tables and other internal uses. The 1002** argument should be a char** which will be filled with the filename 1003** written into memory obtained from [sqlite3_malloc()]. The caller should 1004** invoke [sqlite3_free()] on the result to avoid a memory leak. 1005** 1006** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 1007** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 1008** maximum number of bytes that will be used for memory-mapped I/O. 1009** The argument is a pointer to a value of type sqlite3_int64 that 1010** is an advisory maximum number of bytes in the file to memory map. The 1011** pointer is overwritten with the old value. The limit is not changed if 1012** the value originally pointed to is negative, and so the current limit 1013** can be queried by passing in a pointer to a negative number. This 1014** file-control is used internally to implement [PRAGMA mmap_size]. 1015** 1016** <li>[[SQLITE_FCNTL_TRACE]] 1017** The [SQLITE_FCNTL_TRACE] file control provides advisory information 1018** to the VFS about what the higher layers of the SQLite stack are doing. 1019** This file control is used by some VFS activity tracing [shims]. 1020** The argument is a zero-terminated string. Higher layers in the 1021** SQLite stack may generate instances of this file control if 1022** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 1023** 1024** <li>[[SQLITE_FCNTL_HAS_MOVED]] 1025** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 1026** pointer to an integer and it writes a boolean into that integer depending 1027** on whether or not the file has been renamed, moved, or deleted since it 1028** was first opened. 1029** 1030** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1031** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1032** underlying native file handle associated with a file handle. This file 1033** control interprets its argument as a pointer to a native file handle and 1034** writes the resulting value there. 1035** 1036** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1037** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1038** opcode causes the xFileControl method to swap the file handle with the one 1039** pointed to by the pArg argument. This capability is used during testing 1040** and only needs to be supported when SQLITE_TEST is defined. 1041** 1042** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1043** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1044** be advantageous to block on the next WAL lock if the lock is not immediately 1045** available. The WAL subsystem issues this signal during rare 1046** circumstances in order to fix a problem with priority inversion. 1047** Applications should <em>not</em> use this file-control. 1048** 1049** <li>[[SQLITE_FCNTL_ZIPVFS]] 1050** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1051** VFS should return SQLITE_NOTFOUND for this opcode. 1052** 1053** <li>[[SQLITE_FCNTL_RBU]] 1054** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1055** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1056** this opcode. 1057** 1058** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1059** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1060** the file descriptor is placed in "batch write mode", which 1061** means all subsequent write operations will be deferred and done 1062** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1063** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1064** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1065** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1066** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1067** no VFS interface calls on the same [sqlite3_file] file descriptor 1068** except for calls to the xWrite method and the xFileControl method 1069** with [SQLITE_FCNTL_SIZE_HINT]. 1070** 1071** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1072** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1073** operations since the previous successful call to 1074** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1075** This file control returns [SQLITE_OK] if and only if the writes were 1076** all performed successfully and have been committed to persistent storage. 1077** ^Regardless of whether or not it is successful, this file control takes 1078** the file descriptor out of batch write mode so that all subsequent 1079** write operations are independent. 1080** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1081** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1082** 1083** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1084** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1085** operations since the previous successful call to 1086** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1087** ^This file control takes the file descriptor out of batch write mode 1088** so that all subsequent write operations are independent. 1089** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1090** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1091** 1092** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]] 1093** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS 1094** to block for up to M milliseconds before failing when attempting to 1095** obtain a file lock using the xLock or xShmLock methods of the VFS. 1096** The parameter is a pointer to a 32-bit signed integer that contains 1097** the value that M is to be set to. Before returning, the 32-bit signed 1098** integer is overwritten with the previous value of M. 1099** 1100** <li>[[SQLITE_FCNTL_DATA_VERSION]] 1101** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to 1102** a database file. The argument is a pointer to a 32-bit unsigned integer. 1103** The "data version" for the pager is written into the pointer. The 1104** "data version" changes whenever any change occurs to the corresponding 1105** database file, either through SQL statements on the same database 1106** connection or through transactions committed by separate database 1107** connections possibly in other processes. The [sqlite3_total_changes()] 1108** interface can be used to find if any database on the connection has changed, 1109** but that interface responds to changes on TEMP as well as MAIN and does 1110** not provide a mechanism to detect changes to MAIN only. Also, the 1111** [sqlite3_total_changes()] interface responds to internal changes only and 1112** omits changes made by other database connections. The 1113** [PRAGMA data_version] command provides a mechanism to detect changes to 1114** a single attached database that occur due to other database connections, 1115** but omits changes implemented by the database connection on which it is 1116** called. This file control is the only mechanism to detect changes that 1117** happen either internally or externally and that are associated with 1118** a particular attached database. 1119** 1120** <li>[[SQLITE_FCNTL_CKPT_START]] 1121** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint 1122** in wal mode before the client starts to copy pages from the wal 1123** file to the database file. 1124** 1125** <li>[[SQLITE_FCNTL_CKPT_DONE]] 1126** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint 1127** in wal mode after the client has finished copying pages from the wal 1128** file to the database file, but before the *-shm file is updated to 1129** record the fact that the pages have been checkpointed. 1130** </ul> 1131*/ 1132#define SQLITE_FCNTL_LOCKSTATE 1 1133#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1134#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1135#define SQLITE_FCNTL_LAST_ERRNO 4 1136#define SQLITE_FCNTL_SIZE_HINT 5 1137#define SQLITE_FCNTL_CHUNK_SIZE 6 1138#define SQLITE_FCNTL_FILE_POINTER 7 1139#define SQLITE_FCNTL_SYNC_OMITTED 8 1140#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1141#define SQLITE_FCNTL_PERSIST_WAL 10 1142#define SQLITE_FCNTL_OVERWRITE 11 1143#define SQLITE_FCNTL_VFSNAME 12 1144#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1145#define SQLITE_FCNTL_PRAGMA 14 1146#define SQLITE_FCNTL_BUSYHANDLER 15 1147#define SQLITE_FCNTL_TEMPFILENAME 16 1148#define SQLITE_FCNTL_MMAP_SIZE 18 1149#define SQLITE_FCNTL_TRACE 19 1150#define SQLITE_FCNTL_HAS_MOVED 20 1151#define SQLITE_FCNTL_SYNC 21 1152#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1153#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1154#define SQLITE_FCNTL_WAL_BLOCK 24 1155#define SQLITE_FCNTL_ZIPVFS 25 1156#define SQLITE_FCNTL_RBU 26 1157#define SQLITE_FCNTL_VFS_POINTER 27 1158#define SQLITE_FCNTL_JOURNAL_POINTER 28 1159#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1160#define SQLITE_FCNTL_PDB 30 1161#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1162#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1163#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1164#define SQLITE_FCNTL_LOCK_TIMEOUT 34 1165#define SQLITE_FCNTL_DATA_VERSION 35 1166#define SQLITE_FCNTL_SIZE_LIMIT 36 1167#define SQLITE_FCNTL_CKPT_DONE 37 1168#define SQLITE_FCNTL_RESERVE_BYTES 38 1169#define SQLITE_FCNTL_CKPT_START 39 1170 1171/* deprecated names */ 1172#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1173#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1174#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1175 1176 1177/* 1178** CAPI3REF: Mutex Handle 1179** 1180** The mutex module within SQLite defines [sqlite3_mutex] to be an 1181** abstract type for a mutex object. The SQLite core never looks 1182** at the internal representation of an [sqlite3_mutex]. It only 1183** deals with pointers to the [sqlite3_mutex] object. 1184** 1185** Mutexes are created using [sqlite3_mutex_alloc()]. 1186*/ 1187typedef struct sqlite3_mutex sqlite3_mutex; 1188 1189/* 1190** CAPI3REF: Loadable Extension Thunk 1191** 1192** A pointer to the opaque sqlite3_api_routines structure is passed as 1193** the third parameter to entry points of [loadable extensions]. This 1194** structure must be typedefed in order to work around compiler warnings 1195** on some platforms. 1196*/ 1197typedef struct sqlite3_api_routines sqlite3_api_routines; 1198 1199/* 1200** CAPI3REF: OS Interface Object 1201** 1202** An instance of the sqlite3_vfs object defines the interface between 1203** the SQLite core and the underlying operating system. The "vfs" 1204** in the name of the object stands for "virtual file system". See 1205** the [VFS | VFS documentation] for further information. 1206** 1207** The VFS interface is sometimes extended by adding new methods onto 1208** the end. Each time such an extension occurs, the iVersion field 1209** is incremented. The iVersion value started out as 1 in 1210** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1211** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1212** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1213** may be appended to the sqlite3_vfs object and the iVersion value 1214** may increase again in future versions of SQLite. 1215** Note that due to an oversight, the structure 1216** of the sqlite3_vfs object changed in the transition from 1217** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1218** and yet the iVersion field was not increased. 1219** 1220** The szOsFile field is the size of the subclassed [sqlite3_file] 1221** structure used by this VFS. mxPathname is the maximum length of 1222** a pathname in this VFS. 1223** 1224** Registered sqlite3_vfs objects are kept on a linked list formed by 1225** the pNext pointer. The [sqlite3_vfs_register()] 1226** and [sqlite3_vfs_unregister()] interfaces manage this list 1227** in a thread-safe way. The [sqlite3_vfs_find()] interface 1228** searches the list. Neither the application code nor the VFS 1229** implementation should use the pNext pointer. 1230** 1231** The pNext field is the only field in the sqlite3_vfs 1232** structure that SQLite will ever modify. SQLite will only access 1233** or modify this field while holding a particular static mutex. 1234** The application should never modify anything within the sqlite3_vfs 1235** object once the object has been registered. 1236** 1237** The zName field holds the name of the VFS module. The name must 1238** be unique across all VFS modules. 1239** 1240** [[sqlite3_vfs.xOpen]] 1241** ^SQLite guarantees that the zFilename parameter to xOpen 1242** is either a NULL pointer or string obtained 1243** from xFullPathname() with an optional suffix added. 1244** ^If a suffix is added to the zFilename parameter, it will 1245** consist of a single "-" character followed by no more than 1246** 11 alphanumeric and/or "-" characters. 1247** ^SQLite further guarantees that 1248** the string will be valid and unchanged until xClose() is 1249** called. Because of the previous sentence, 1250** the [sqlite3_file] can safely store a pointer to the 1251** filename if it needs to remember the filename for some reason. 1252** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1253** must invent its own temporary name for the file. ^Whenever the 1254** xFilename parameter is NULL it will also be the case that the 1255** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1256** 1257** The flags argument to xOpen() includes all bits set in 1258** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1259** or [sqlite3_open16()] is used, then flags includes at least 1260** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1261** If xOpen() opens a file read-only then it sets *pOutFlags to 1262** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1263** 1264** ^(SQLite will also add one of the following flags to the xOpen() 1265** call, depending on the object being opened: 1266** 1267** <ul> 1268** <li> [SQLITE_OPEN_MAIN_DB] 1269** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1270** <li> [SQLITE_OPEN_TEMP_DB] 1271** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1272** <li> [SQLITE_OPEN_TRANSIENT_DB] 1273** <li> [SQLITE_OPEN_SUBJOURNAL] 1274** <li> [SQLITE_OPEN_SUPER_JOURNAL] 1275** <li> [SQLITE_OPEN_WAL] 1276** </ul>)^ 1277** 1278** The file I/O implementation can use the object type flags to 1279** change the way it deals with files. For example, an application 1280** that does not care about crash recovery or rollback might make 1281** the open of a journal file a no-op. Writes to this journal would 1282** also be no-ops, and any attempt to read the journal would return 1283** SQLITE_IOERR. Or the implementation might recognize that a database 1284** file will be doing page-aligned sector reads and writes in a random 1285** order and set up its I/O subsystem accordingly. 1286** 1287** SQLite might also add one of the following flags to the xOpen method: 1288** 1289** <ul> 1290** <li> [SQLITE_OPEN_DELETEONCLOSE] 1291** <li> [SQLITE_OPEN_EXCLUSIVE] 1292** </ul> 1293** 1294** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1295** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1296** will be set for TEMP databases and their journals, transient 1297** databases, and subjournals. 1298** 1299** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1300** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1301** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1302** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1303** SQLITE_OPEN_CREATE, is used to indicate that file should always 1304** be created, and that it is an error if it already exists. 1305** It is <i>not</i> used to indicate the file should be opened 1306** for exclusive access. 1307** 1308** ^At least szOsFile bytes of memory are allocated by SQLite 1309** to hold the [sqlite3_file] structure passed as the third 1310** argument to xOpen. The xOpen method does not have to 1311** allocate the structure; it should just fill it in. Note that 1312** the xOpen method must set the sqlite3_file.pMethods to either 1313** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1314** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1315** element will be valid after xOpen returns regardless of the success 1316** or failure of the xOpen call. 1317** 1318** [[sqlite3_vfs.xAccess]] 1319** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1320** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1321** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1322** to test whether a file is at least readable. The SQLITE_ACCESS_READ 1323** flag is never actually used and is not implemented in the built-in 1324** VFSes of SQLite. The file is named by the second argument and can be a 1325** directory. The xAccess method returns [SQLITE_OK] on success or some 1326** non-zero error code if there is an I/O error or if the name of 1327** the file given in the second argument is illegal. If SQLITE_OK 1328** is returned, then non-zero or zero is written into *pResOut to indicate 1329** whether or not the file is accessible. 1330** 1331** ^SQLite will always allocate at least mxPathname+1 bytes for the 1332** output buffer xFullPathname. The exact size of the output buffer 1333** is also passed as a parameter to both methods. If the output buffer 1334** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1335** handled as a fatal error by SQLite, vfs implementations should endeavor 1336** to prevent this by setting mxPathname to a sufficiently large value. 1337** 1338** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1339** interfaces are not strictly a part of the filesystem, but they are 1340** included in the VFS structure for completeness. 1341** The xRandomness() function attempts to return nBytes bytes 1342** of good-quality randomness into zOut. The return value is 1343** the actual number of bytes of randomness obtained. 1344** The xSleep() method causes the calling thread to sleep for at 1345** least the number of microseconds given. ^The xCurrentTime() 1346** method returns a Julian Day Number for the current date and time as 1347** a floating point value. 1348** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1349** Day Number multiplied by 86400000 (the number of milliseconds in 1350** a 24-hour day). 1351** ^SQLite will use the xCurrentTimeInt64() method to get the current 1352** date and time if that method is available (if iVersion is 2 or 1353** greater and the function pointer is not NULL) and will fall back 1354** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1355** 1356** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1357** are not used by the SQLite core. These optional interfaces are provided 1358** by some VFSes to facilitate testing of the VFS code. By overriding 1359** system calls with functions under its control, a test program can 1360** simulate faults and error conditions that would otherwise be difficult 1361** or impossible to induce. The set of system calls that can be overridden 1362** varies from one VFS to another, and from one version of the same VFS to the 1363** next. Applications that use these interfaces must be prepared for any 1364** or all of these interfaces to be NULL or for their behavior to change 1365** from one release to the next. Applications must not attempt to access 1366** any of these methods if the iVersion of the VFS is less than 3. 1367*/ 1368typedef struct sqlite3_vfs sqlite3_vfs; 1369typedef void (*sqlite3_syscall_ptr)(void); 1370struct sqlite3_vfs { 1371 int iVersion; /* Structure version number (currently 3) */ 1372 int szOsFile; /* Size of subclassed sqlite3_file */ 1373 int mxPathname; /* Maximum file pathname length */ 1374 sqlite3_vfs *pNext; /* Next registered VFS */ 1375 const char *zName; /* Name of this virtual file system */ 1376 void *pAppData; /* Pointer to application-specific data */ 1377 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1378 int flags, int *pOutFlags); 1379 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1380 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1381 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1382 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1383 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1384 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1385 void (*xDlClose)(sqlite3_vfs*, void*); 1386 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1387 int (*xSleep)(sqlite3_vfs*, int microseconds); 1388 int (*xCurrentTime)(sqlite3_vfs*, double*); 1389 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1390 /* 1391 ** The methods above are in version 1 of the sqlite_vfs object 1392 ** definition. Those that follow are added in version 2 or later 1393 */ 1394 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1395 /* 1396 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1397 ** Those below are for version 3 and greater. 1398 */ 1399 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1400 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1401 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1402 /* 1403 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1404 ** New fields may be appended in future versions. The iVersion 1405 ** value will increment whenever this happens. 1406 */ 1407}; 1408 1409/* 1410** CAPI3REF: Flags for the xAccess VFS method 1411** 1412** These integer constants can be used as the third parameter to 1413** the xAccess method of an [sqlite3_vfs] object. They determine 1414** what kind of permissions the xAccess method is looking for. 1415** With SQLITE_ACCESS_EXISTS, the xAccess method 1416** simply checks whether the file exists. 1417** With SQLITE_ACCESS_READWRITE, the xAccess method 1418** checks whether the named directory is both readable and writable 1419** (in other words, if files can be added, removed, and renamed within 1420** the directory). 1421** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1422** [temp_store_directory pragma], though this could change in a future 1423** release of SQLite. 1424** With SQLITE_ACCESS_READ, the xAccess method 1425** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1426** currently unused, though it might be used in a future release of 1427** SQLite. 1428*/ 1429#define SQLITE_ACCESS_EXISTS 0 1430#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1431#define SQLITE_ACCESS_READ 2 /* Unused */ 1432 1433/* 1434** CAPI3REF: Flags for the xShmLock VFS method 1435** 1436** These integer constants define the various locking operations 1437** allowed by the xShmLock method of [sqlite3_io_methods]. The 1438** following are the only legal combinations of flags to the 1439** xShmLock method: 1440** 1441** <ul> 1442** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1443** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1444** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1445** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1446** </ul> 1447** 1448** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1449** was given on the corresponding lock. 1450** 1451** The xShmLock method can transition between unlocked and SHARED or 1452** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1453** and EXCLUSIVE. 1454*/ 1455#define SQLITE_SHM_UNLOCK 1 1456#define SQLITE_SHM_LOCK 2 1457#define SQLITE_SHM_SHARED 4 1458#define SQLITE_SHM_EXCLUSIVE 8 1459 1460/* 1461** CAPI3REF: Maximum xShmLock index 1462** 1463** The xShmLock method on [sqlite3_io_methods] may use values 1464** between 0 and this upper bound as its "offset" argument. 1465** The SQLite core will never attempt to acquire or release a 1466** lock outside of this range 1467*/ 1468#define SQLITE_SHM_NLOCK 8 1469 1470 1471/* 1472** CAPI3REF: Initialize The SQLite Library 1473** 1474** ^The sqlite3_initialize() routine initializes the 1475** SQLite library. ^The sqlite3_shutdown() routine 1476** deallocates any resources that were allocated by sqlite3_initialize(). 1477** These routines are designed to aid in process initialization and 1478** shutdown on embedded systems. Workstation applications using 1479** SQLite normally do not need to invoke either of these routines. 1480** 1481** A call to sqlite3_initialize() is an "effective" call if it is 1482** the first time sqlite3_initialize() is invoked during the lifetime of 1483** the process, or if it is the first time sqlite3_initialize() is invoked 1484** following a call to sqlite3_shutdown(). ^(Only an effective call 1485** of sqlite3_initialize() does any initialization. All other calls 1486** are harmless no-ops.)^ 1487** 1488** A call to sqlite3_shutdown() is an "effective" call if it is the first 1489** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1490** an effective call to sqlite3_shutdown() does any deinitialization. 1491** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1492** 1493** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1494** is not. The sqlite3_shutdown() interface must only be called from a 1495** single thread. All open [database connections] must be closed and all 1496** other SQLite resources must be deallocated prior to invoking 1497** sqlite3_shutdown(). 1498** 1499** Among other things, ^sqlite3_initialize() will invoke 1500** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1501** will invoke sqlite3_os_end(). 1502** 1503** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1504** ^If for some reason, sqlite3_initialize() is unable to initialize 1505** the library (perhaps it is unable to allocate a needed resource such 1506** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1507** 1508** ^The sqlite3_initialize() routine is called internally by many other 1509** SQLite interfaces so that an application usually does not need to 1510** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1511** calls sqlite3_initialize() so the SQLite library will be automatically 1512** initialized when [sqlite3_open()] is called if it has not be initialized 1513** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1514** compile-time option, then the automatic calls to sqlite3_initialize() 1515** are omitted and the application must call sqlite3_initialize() directly 1516** prior to using any other SQLite interface. For maximum portability, 1517** it is recommended that applications always invoke sqlite3_initialize() 1518** directly prior to using any other SQLite interface. Future releases 1519** of SQLite may require this. In other words, the behavior exhibited 1520** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1521** default behavior in some future release of SQLite. 1522** 1523** The sqlite3_os_init() routine does operating-system specific 1524** initialization of the SQLite library. The sqlite3_os_end() 1525** routine undoes the effect of sqlite3_os_init(). Typical tasks 1526** performed by these routines include allocation or deallocation 1527** of static resources, initialization of global variables, 1528** setting up a default [sqlite3_vfs] module, or setting up 1529** a default configuration using [sqlite3_config()]. 1530** 1531** The application should never invoke either sqlite3_os_init() 1532** or sqlite3_os_end() directly. The application should only invoke 1533** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1534** interface is called automatically by sqlite3_initialize() and 1535** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1536** implementations for sqlite3_os_init() and sqlite3_os_end() 1537** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1538** When [custom builds | built for other platforms] 1539** (using the [SQLITE_OS_OTHER=1] compile-time 1540** option) the application must supply a suitable implementation for 1541** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1542** implementation of sqlite3_os_init() or sqlite3_os_end() 1543** must return [SQLITE_OK] on success and some other [error code] upon 1544** failure. 1545*/ 1546int sqlite3_initialize(void); 1547int sqlite3_shutdown(void); 1548int sqlite3_os_init(void); 1549int sqlite3_os_end(void); 1550 1551/* 1552** CAPI3REF: Configuring The SQLite Library 1553** 1554** The sqlite3_config() interface is used to make global configuration 1555** changes to SQLite in order to tune SQLite to the specific needs of 1556** the application. The default configuration is recommended for most 1557** applications and so this routine is usually not necessary. It is 1558** provided to support rare applications with unusual needs. 1559** 1560** <b>The sqlite3_config() interface is not threadsafe. The application 1561** must ensure that no other SQLite interfaces are invoked by other 1562** threads while sqlite3_config() is running.</b> 1563** 1564** The sqlite3_config() interface 1565** may only be invoked prior to library initialization using 1566** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1567** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1568** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1569** Note, however, that ^sqlite3_config() can be called as part of the 1570** implementation of an application-defined [sqlite3_os_init()]. 1571** 1572** The first argument to sqlite3_config() is an integer 1573** [configuration option] that determines 1574** what property of SQLite is to be configured. Subsequent arguments 1575** vary depending on the [configuration option] 1576** in the first argument. 1577** 1578** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1579** ^If the option is unknown or SQLite is unable to set the option 1580** then this routine returns a non-zero [error code]. 1581*/ 1582int sqlite3_config(int, ...); 1583 1584/* 1585** CAPI3REF: Configure database connections 1586** METHOD: sqlite3 1587** 1588** The sqlite3_db_config() interface is used to make configuration 1589** changes to a [database connection]. The interface is similar to 1590** [sqlite3_config()] except that the changes apply to a single 1591** [database connection] (specified in the first argument). 1592** 1593** The second argument to sqlite3_db_config(D,V,...) is the 1594** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1595** that indicates what aspect of the [database connection] is being configured. 1596** Subsequent arguments vary depending on the configuration verb. 1597** 1598** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1599** the call is considered successful. 1600*/ 1601int sqlite3_db_config(sqlite3*, int op, ...); 1602 1603/* 1604** CAPI3REF: Memory Allocation Routines 1605** 1606** An instance of this object defines the interface between SQLite 1607** and low-level memory allocation routines. 1608** 1609** This object is used in only one place in the SQLite interface. 1610** A pointer to an instance of this object is the argument to 1611** [sqlite3_config()] when the configuration option is 1612** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1613** By creating an instance of this object 1614** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1615** during configuration, an application can specify an alternative 1616** memory allocation subsystem for SQLite to use for all of its 1617** dynamic memory needs. 1618** 1619** Note that SQLite comes with several [built-in memory allocators] 1620** that are perfectly adequate for the overwhelming majority of applications 1621** and that this object is only useful to a tiny minority of applications 1622** with specialized memory allocation requirements. This object is 1623** also used during testing of SQLite in order to specify an alternative 1624** memory allocator that simulates memory out-of-memory conditions in 1625** order to verify that SQLite recovers gracefully from such 1626** conditions. 1627** 1628** The xMalloc, xRealloc, and xFree methods must work like the 1629** malloc(), realloc() and free() functions from the standard C library. 1630** ^SQLite guarantees that the second argument to 1631** xRealloc is always a value returned by a prior call to xRoundup. 1632** 1633** xSize should return the allocated size of a memory allocation 1634** previously obtained from xMalloc or xRealloc. The allocated size 1635** is always at least as big as the requested size but may be larger. 1636** 1637** The xRoundup method returns what would be the allocated size of 1638** a memory allocation given a particular requested size. Most memory 1639** allocators round up memory allocations at least to the next multiple 1640** of 8. Some allocators round up to a larger multiple or to a power of 2. 1641** Every memory allocation request coming in through [sqlite3_malloc()] 1642** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1643** that causes the corresponding memory allocation to fail. 1644** 1645** The xInit method initializes the memory allocator. For example, 1646** it might allocate any required mutexes or initialize internal data 1647** structures. The xShutdown method is invoked (indirectly) by 1648** [sqlite3_shutdown()] and should deallocate any resources acquired 1649** by xInit. The pAppData pointer is used as the only parameter to 1650** xInit and xShutdown. 1651** 1652** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes 1653** the xInit method, so the xInit method need not be threadsafe. The 1654** xShutdown method is only called from [sqlite3_shutdown()] so it does 1655** not need to be threadsafe either. For all other methods, SQLite 1656** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1657** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1658** it is by default) and so the methods are automatically serialized. 1659** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1660** methods must be threadsafe or else make their own arrangements for 1661** serialization. 1662** 1663** SQLite will never invoke xInit() more than once without an intervening 1664** call to xShutdown(). 1665*/ 1666typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1667struct sqlite3_mem_methods { 1668 void *(*xMalloc)(int); /* Memory allocation function */ 1669 void (*xFree)(void*); /* Free a prior allocation */ 1670 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1671 int (*xSize)(void*); /* Return the size of an allocation */ 1672 int (*xRoundup)(int); /* Round up request size to allocation size */ 1673 int (*xInit)(void*); /* Initialize the memory allocator */ 1674 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1675 void *pAppData; /* Argument to xInit() and xShutdown() */ 1676}; 1677 1678/* 1679** CAPI3REF: Configuration Options 1680** KEYWORDS: {configuration option} 1681** 1682** These constants are the available integer configuration options that 1683** can be passed as the first argument to the [sqlite3_config()] interface. 1684** 1685** New configuration options may be added in future releases of SQLite. 1686** Existing configuration options might be discontinued. Applications 1687** should check the return code from [sqlite3_config()] to make sure that 1688** the call worked. The [sqlite3_config()] interface will return a 1689** non-zero [error code] if a discontinued or unsupported configuration option 1690** is invoked. 1691** 1692** <dl> 1693** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1694** <dd>There are no arguments to this option. ^This option sets the 1695** [threading mode] to Single-thread. In other words, it disables 1696** all mutexing and puts SQLite into a mode where it can only be used 1697** by a single thread. ^If SQLite is compiled with 1698** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1699** it is not possible to change the [threading mode] from its default 1700** value of Single-thread and so [sqlite3_config()] will return 1701** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1702** configuration option.</dd> 1703** 1704** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1705** <dd>There are no arguments to this option. ^This option sets the 1706** [threading mode] to Multi-thread. In other words, it disables 1707** mutexing on [database connection] and [prepared statement] objects. 1708** The application is responsible for serializing access to 1709** [database connections] and [prepared statements]. But other mutexes 1710** are enabled so that SQLite will be safe to use in a multi-threaded 1711** environment as long as no two threads attempt to use the same 1712** [database connection] at the same time. ^If SQLite is compiled with 1713** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1714** it is not possible to set the Multi-thread [threading mode] and 1715** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1716** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1717** 1718** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1719** <dd>There are no arguments to this option. ^This option sets the 1720** [threading mode] to Serialized. In other words, this option enables 1721** all mutexes including the recursive 1722** mutexes on [database connection] and [prepared statement] objects. 1723** In this mode (which is the default when SQLite is compiled with 1724** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1725** to [database connections] and [prepared statements] so that the 1726** application is free to use the same [database connection] or the 1727** same [prepared statement] in different threads at the same time. 1728** ^If SQLite is compiled with 1729** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1730** it is not possible to set the Serialized [threading mode] and 1731** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1732** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1733** 1734** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1735** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1736** a pointer to an instance of the [sqlite3_mem_methods] structure. 1737** The argument specifies 1738** alternative low-level memory allocation routines to be used in place of 1739** the memory allocation routines built into SQLite.)^ ^SQLite makes 1740** its own private copy of the content of the [sqlite3_mem_methods] structure 1741** before the [sqlite3_config()] call returns.</dd> 1742** 1743** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1744** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1745** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1746** The [sqlite3_mem_methods] 1747** structure is filled with the currently defined memory allocation routines.)^ 1748** This option can be used to overload the default memory allocation 1749** routines with a wrapper that simulations memory allocation failure or 1750** tracks memory usage, for example. </dd> 1751** 1752** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1753** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1754** type int, interpreted as a boolean, which if true provides a hint to 1755** SQLite that it should avoid large memory allocations if possible. 1756** SQLite will run faster if it is free to make large memory allocations, 1757** but some application might prefer to run slower in exchange for 1758** guarantees about memory fragmentation that are possible if large 1759** allocations are avoided. This hint is normally off. 1760** </dd> 1761** 1762** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1763** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1764** interpreted as a boolean, which enables or disables the collection of 1765** memory allocation statistics. ^(When memory allocation statistics are 1766** disabled, the following SQLite interfaces become non-operational: 1767** <ul> 1768** <li> [sqlite3_hard_heap_limit64()] 1769** <li> [sqlite3_memory_used()] 1770** <li> [sqlite3_memory_highwater()] 1771** <li> [sqlite3_soft_heap_limit64()] 1772** <li> [sqlite3_status64()] 1773** </ul>)^ 1774** ^Memory allocation statistics are enabled by default unless SQLite is 1775** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1776** allocation statistics are disabled by default. 1777** </dd> 1778** 1779** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1780** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1781** </dd> 1782** 1783** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1784** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1785** that SQLite can use for the database page cache with the default page 1786** cache implementation. 1787** This configuration option is a no-op if an application-defined page 1788** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1789** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1790** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1791** and the number of cache lines (N). 1792** The sz argument should be the size of the largest database page 1793** (a power of two between 512 and 65536) plus some extra bytes for each 1794** page header. ^The number of extra bytes needed by the page header 1795** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1796** ^It is harmless, apart from the wasted memory, 1797** for the sz parameter to be larger than necessary. The pMem 1798** argument must be either a NULL pointer or a pointer to an 8-byte 1799** aligned block of memory of at least sz*N bytes, otherwise 1800** subsequent behavior is undefined. 1801** ^When pMem is not NULL, SQLite will strive to use the memory provided 1802** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1803** a page cache line is larger than sz bytes or if all of the pMem buffer 1804** is exhausted. 1805** ^If pMem is NULL and N is non-zero, then each database connection 1806** does an initial bulk allocation for page cache memory 1807** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1808** of -1024*N bytes if N is negative, . ^If additional 1809** page cache memory is needed beyond what is provided by the initial 1810** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1811** additional cache line. </dd> 1812** 1813** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1814** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1815** that SQLite will use for all of its dynamic memory allocation needs 1816** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1817** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1818** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1819** [SQLITE_ERROR] if invoked otherwise. 1820** ^There are three arguments to SQLITE_CONFIG_HEAP: 1821** An 8-byte aligned pointer to the memory, 1822** the number of bytes in the memory buffer, and the minimum allocation size. 1823** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1824** to using its default memory allocator (the system malloc() implementation), 1825** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1826** memory pointer is not NULL then the alternative memory 1827** allocator is engaged to handle all of SQLites memory allocation needs. 1828** The first pointer (the memory pointer) must be aligned to an 8-byte 1829** boundary or subsequent behavior of SQLite will be undefined. 1830** The minimum allocation size is capped at 2**12. Reasonable values 1831** for the minimum allocation size are 2**5 through 2**8.</dd> 1832** 1833** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1834** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1835** pointer to an instance of the [sqlite3_mutex_methods] structure. 1836** The argument specifies alternative low-level mutex routines to be used 1837** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1838** the content of the [sqlite3_mutex_methods] structure before the call to 1839** [sqlite3_config()] returns. ^If SQLite is compiled with 1840** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1841** the entire mutexing subsystem is omitted from the build and hence calls to 1842** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1843** return [SQLITE_ERROR].</dd> 1844** 1845** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1846** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1847** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1848** [sqlite3_mutex_methods] 1849** structure is filled with the currently defined mutex routines.)^ 1850** This option can be used to overload the default mutex allocation 1851** routines with a wrapper used to track mutex usage for performance 1852** profiling or testing, for example. ^If SQLite is compiled with 1853** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1854** the entire mutexing subsystem is omitted from the build and hence calls to 1855** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1856** return [SQLITE_ERROR].</dd> 1857** 1858** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1859** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1860** the default size of lookaside memory on each [database connection]. 1861** The first argument is the 1862** size of each lookaside buffer slot and the second is the number of 1863** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1864** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1865** option to [sqlite3_db_config()] can be used to change the lookaside 1866** configuration on individual connections.)^ </dd> 1867** 1868** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1869** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1870** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1871** the interface to a custom page cache implementation.)^ 1872** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1873** 1874** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1875** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1876** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1877** the current page cache implementation into that object.)^ </dd> 1878** 1879** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1880** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1881** global [error log]. 1882** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1883** function with a call signature of void(*)(void*,int,const char*), 1884** and a pointer to void. ^If the function pointer is not NULL, it is 1885** invoked by [sqlite3_log()] to process each logging event. ^If the 1886** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1887** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1888** passed through as the first parameter to the application-defined logger 1889** function whenever that function is invoked. ^The second parameter to 1890** the logger function is a copy of the first parameter to the corresponding 1891** [sqlite3_log()] call and is intended to be a [result code] or an 1892** [extended result code]. ^The third parameter passed to the logger is 1893** log message after formatting via [sqlite3_snprintf()]. 1894** The SQLite logging interface is not reentrant; the logger function 1895** supplied by the application must not invoke any SQLite interface. 1896** In a multi-threaded application, the application-defined logger 1897** function must be threadsafe. </dd> 1898** 1899** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1900** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1901** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1902** then URI handling is globally disabled.)^ ^If URI handling is globally 1903** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1904** [sqlite3_open16()] or 1905** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1906** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1907** connection is opened. ^If it is globally disabled, filenames are 1908** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1909** database connection is opened. ^(By default, URI handling is globally 1910** disabled. The default value may be changed by compiling with the 1911** [SQLITE_USE_URI] symbol defined.)^ 1912** 1913** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1914** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1915** argument which is interpreted as a boolean in order to enable or disable 1916** the use of covering indices for full table scans in the query optimizer. 1917** ^The default setting is determined 1918** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1919** if that compile-time option is omitted. 1920** The ability to disable the use of covering indices for full table scans 1921** is because some incorrectly coded legacy applications might malfunction 1922** when the optimization is enabled. Providing the ability to 1923** disable the optimization allows the older, buggy application code to work 1924** without change even with newer versions of SQLite. 1925** 1926** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1927** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1928** <dd> These options are obsolete and should not be used by new code. 1929** They are retained for backwards compatibility but are now no-ops. 1930** </dd> 1931** 1932** [[SQLITE_CONFIG_SQLLOG]] 1933** <dt>SQLITE_CONFIG_SQLLOG 1934** <dd>This option is only available if sqlite is compiled with the 1935** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1936** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1937** The second should be of type (void*). The callback is invoked by the library 1938** in three separate circumstances, identified by the value passed as the 1939** fourth parameter. If the fourth parameter is 0, then the database connection 1940** passed as the second argument has just been opened. The third argument 1941** points to a buffer containing the name of the main database file. If the 1942** fourth parameter is 1, then the SQL statement that the third parameter 1943** points to has just been executed. Or, if the fourth parameter is 2, then 1944** the connection being passed as the second parameter is being closed. The 1945** third parameter is passed NULL In this case. An example of using this 1946** configuration option can be seen in the "test_sqllog.c" source file in 1947** the canonical SQLite source tree.</dd> 1948** 1949** [[SQLITE_CONFIG_MMAP_SIZE]] 1950** <dt>SQLITE_CONFIG_MMAP_SIZE 1951** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1952** that are the default mmap size limit (the default setting for 1953** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1954** ^The default setting can be overridden by each database connection using 1955** either the [PRAGMA mmap_size] command, or by using the 1956** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1957** will be silently truncated if necessary so that it does not exceed the 1958** compile-time maximum mmap size set by the 1959** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1960** ^If either argument to this option is negative, then that argument is 1961** changed to its compile-time default. 1962** 1963** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1964** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1965** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1966** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1967** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1968** that specifies the maximum size of the created heap. 1969** 1970** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1971** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1972** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1973** is a pointer to an integer and writes into that integer the number of extra 1974** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1975** The amount of extra space required can change depending on the compiler, 1976** target platform, and SQLite version. 1977** 1978** [[SQLITE_CONFIG_PMASZ]] 1979** <dt>SQLITE_CONFIG_PMASZ 1980** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1981** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1982** sorter to that integer. The default minimum PMA Size is set by the 1983** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1984** to help with sort operations when multithreaded sorting 1985** is enabled (using the [PRAGMA threads] command) and the amount of content 1986** to be sorted exceeds the page size times the minimum of the 1987** [PRAGMA cache_size] setting and this value. 1988** 1989** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1990** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1991** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1992** becomes the [statement journal] spill-to-disk threshold. 1993** [Statement journals] are held in memory until their size (in bytes) 1994** exceeds this threshold, at which point they are written to disk. 1995** Or if the threshold is -1, statement journals are always held 1996** exclusively in memory. 1997** Since many statement journals never become large, setting the spill 1998** threshold to a value such as 64KiB can greatly reduce the amount of 1999** I/O required to support statement rollback. 2000** The default value for this setting is controlled by the 2001** [SQLITE_STMTJRNL_SPILL] compile-time option. 2002** 2003** [[SQLITE_CONFIG_SORTERREF_SIZE]] 2004** <dt>SQLITE_CONFIG_SORTERREF_SIZE 2005** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter 2006** of type (int) - the new value of the sorter-reference size threshold. 2007** Usually, when SQLite uses an external sort to order records according 2008** to an ORDER BY clause, all fields required by the caller are present in the 2009** sorted records. However, if SQLite determines based on the declared type 2010** of a table column that its values are likely to be very large - larger 2011** than the configured sorter-reference size threshold - then a reference 2012** is stored in each sorted record and the required column values loaded 2013** from the database as records are returned in sorted order. The default 2014** value for this option is to never use this optimization. Specifying a 2015** negative value for this option restores the default behaviour. 2016** This option is only available if SQLite is compiled with the 2017** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option. 2018** 2019** [[SQLITE_CONFIG_MEMDB_MAXSIZE]] 2020** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE 2021** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter 2022** [sqlite3_int64] parameter which is the default maximum size for an in-memory 2023** database created using [sqlite3_deserialize()]. This default maximum 2024** size can be adjusted up or down for individual databases using the 2025** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control]. If this 2026** configuration setting is never used, then the default maximum is determined 2027** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option. If that 2028** compile-time option is not set, then the default maximum is 1073741824. 2029** </dl> 2030*/ 2031#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 2032#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 2033#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 2034#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 2035#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 2036#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 2037#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 2038#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 2039#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 2040#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 2041#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 2042/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 2043#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 2044#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 2045#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 2046#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 2047#define SQLITE_CONFIG_URI 17 /* int */ 2048#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 2049#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 2050#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 2051#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 2052#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 2053#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 2054#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 2055#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 2056#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 2057#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 2058#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */ 2059#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */ 2060 2061/* 2062** CAPI3REF: Database Connection Configuration Options 2063** 2064** These constants are the available integer configuration options that 2065** can be passed as the second argument to the [sqlite3_db_config()] interface. 2066** 2067** New configuration options may be added in future releases of SQLite. 2068** Existing configuration options might be discontinued. Applications 2069** should check the return code from [sqlite3_db_config()] to make sure that 2070** the call worked. ^The [sqlite3_db_config()] interface will return a 2071** non-zero [error code] if a discontinued or unsupported configuration option 2072** is invoked. 2073** 2074** <dl> 2075** [[SQLITE_DBCONFIG_LOOKASIDE]] 2076** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 2077** <dd> ^This option takes three additional arguments that determine the 2078** [lookaside memory allocator] configuration for the [database connection]. 2079** ^The first argument (the third parameter to [sqlite3_db_config()] is a 2080** pointer to a memory buffer to use for lookaside memory. 2081** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 2082** may be NULL in which case SQLite will allocate the 2083** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 2084** size of each lookaside buffer slot. ^The third argument is the number of 2085** slots. The size of the buffer in the first argument must be greater than 2086** or equal to the product of the second and third arguments. The buffer 2087** must be aligned to an 8-byte boundary. ^If the second argument to 2088** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 2089** rounded down to the next smaller multiple of 8. ^(The lookaside memory 2090** configuration for a database connection can only be changed when that 2091** connection is not currently using lookaside memory, or in other words 2092** when the "current value" returned by 2093** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 2094** Any attempt to change the lookaside memory configuration when lookaside 2095** memory is in use leaves the configuration unchanged and returns 2096** [SQLITE_BUSY].)^</dd> 2097** 2098** [[SQLITE_DBCONFIG_ENABLE_FKEY]] 2099** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 2100** <dd> ^This option is used to enable or disable the enforcement of 2101** [foreign key constraints]. There should be two additional arguments. 2102** The first argument is an integer which is 0 to disable FK enforcement, 2103** positive to enable FK enforcement or negative to leave FK enforcement 2104** unchanged. The second parameter is a pointer to an integer into which 2105** is written 0 or 1 to indicate whether FK enforcement is off or on 2106** following this call. The second parameter may be a NULL pointer, in 2107** which case the FK enforcement setting is not reported back. </dd> 2108** 2109** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]] 2110** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2111** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2112** There should be two additional arguments. 2113** The first argument is an integer which is 0 to disable triggers, 2114** positive to enable triggers or negative to leave the setting unchanged. 2115** The second parameter is a pointer to an integer into which 2116** is written 0 or 1 to indicate whether triggers are disabled or enabled 2117** following this call. The second parameter may be a NULL pointer, in 2118** which case the trigger setting is not reported back. </dd> 2119** 2120** [[SQLITE_DBCONFIG_ENABLE_VIEW]] 2121** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt> 2122** <dd> ^This option is used to enable or disable [CREATE VIEW | views]. 2123** There should be two additional arguments. 2124** The first argument is an integer which is 0 to disable views, 2125** positive to enable views or negative to leave the setting unchanged. 2126** The second parameter is a pointer to an integer into which 2127** is written 0 or 1 to indicate whether views are disabled or enabled 2128** following this call. The second parameter may be a NULL pointer, in 2129** which case the view setting is not reported back. </dd> 2130** 2131** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]] 2132** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2133** <dd> ^This option is used to enable or disable the 2134** [fts3_tokenizer()] function which is part of the 2135** [FTS3] full-text search engine extension. 2136** There should be two additional arguments. 2137** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2138** positive to enable fts3_tokenizer() or negative to leave the setting 2139** unchanged. 2140** The second parameter is a pointer to an integer into which 2141** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2142** following this call. The second parameter may be a NULL pointer, in 2143** which case the new setting is not reported back. </dd> 2144** 2145** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]] 2146** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2147** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2148** interface independently of the [load_extension()] SQL function. 2149** The [sqlite3_enable_load_extension()] API enables or disables both the 2150** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2151** There should be two additional arguments. 2152** When the first argument to this interface is 1, then only the C-API is 2153** enabled and the SQL function remains disabled. If the first argument to 2154** this interface is 0, then both the C-API and the SQL function are disabled. 2155** If the first argument is -1, then no changes are made to state of either the 2156** C-API or the SQL function. 2157** The second parameter is a pointer to an integer into which 2158** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2159** is disabled or enabled following this call. The second parameter may 2160** be a NULL pointer, in which case the new setting is not reported back. 2161** </dd> 2162** 2163** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2164** <dd> ^This option is used to change the name of the "main" database 2165** schema. ^The sole argument is a pointer to a constant UTF8 string 2166** which will become the new schema name in place of "main". ^SQLite 2167** does not make a copy of the new main schema name string, so the application 2168** must ensure that the argument passed into this DBCONFIG option is unchanged 2169** until after the database connection closes. 2170** </dd> 2171** 2172** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]] 2173** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2174** <dd> Usually, when a database in wal mode is closed or detached from a 2175** database handle, SQLite checks if this will mean that there are now no 2176** connections at all to the database. If so, it performs a checkpoint 2177** operation before closing the connection. This option may be used to 2178** override this behaviour. The first parameter passed to this operation 2179** is an integer - positive to disable checkpoints-on-close, or zero (the 2180** default) to enable them, and negative to leave the setting unchanged. 2181** The second parameter is a pointer to an integer 2182** into which is written 0 or 1 to indicate whether checkpoints-on-close 2183** have been disabled - 0 if they are not disabled, 1 if they are. 2184** </dd> 2185** 2186** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2187** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2188** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2189** a single SQL query statement will always use the same algorithm regardless 2190** of values of [bound parameters].)^ The QPSG disables some query optimizations 2191** that look at the values of bound parameters, which can make some queries 2192** slower. But the QPSG has the advantage of more predictable behavior. With 2193** the QPSG active, SQLite will always use the same query plan in the field as 2194** was used during testing in the lab. 2195** The first argument to this setting is an integer which is 0 to disable 2196** the QPSG, positive to enable QPSG, or negative to leave the setting 2197** unchanged. The second parameter is a pointer to an integer into which 2198** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2199** following this call. 2200** </dd> 2201** 2202** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2203** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2204** include output for any operations performed by trigger programs. This 2205** option is used to set or clear (the default) a flag that governs this 2206** behavior. The first parameter passed to this operation is an integer - 2207** positive to enable output for trigger programs, or zero to disable it, 2208** or negative to leave the setting unchanged. 2209** The second parameter is a pointer to an integer into which is written 2210** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2211** it is not disabled, 1 if it is. 2212** </dd> 2213** 2214** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt> 2215** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run 2216** [VACUUM] in order to reset a database back to an empty database 2217** with no schema and no content. The following process works even for 2218** a badly corrupted database file: 2219** <ol> 2220** <li> If the database connection is newly opened, make sure it has read the 2221** database schema by preparing then discarding some query against the 2222** database, or calling sqlite3_table_column_metadata(), ignoring any 2223** errors. This step is only necessary if the application desires to keep 2224** the database in WAL mode after the reset if it was in WAL mode before 2225** the reset. 2226** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0); 2227** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0); 2228** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0); 2229** </ol> 2230** Because resetting a database is destructive and irreversible, the 2231** process requires the use of this obscure API and multiple steps to help 2232** ensure that it does not happen by accident. 2233** 2234** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt> 2235** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the 2236** "defensive" flag for a database connection. When the defensive 2237** flag is enabled, language features that allow ordinary SQL to 2238** deliberately corrupt the database file are disabled. The disabled 2239** features include but are not limited to the following: 2240** <ul> 2241** <li> The [PRAGMA writable_schema=ON] statement. 2242** <li> The [PRAGMA journal_mode=OFF] statement. 2243** <li> Writes to the [sqlite_dbpage] virtual table. 2244** <li> Direct writes to [shadow tables]. 2245** </ul> 2246** </dd> 2247** 2248** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt> 2249** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the 2250** "writable_schema" flag. This has the same effect and is logically equivalent 2251** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF]. 2252** The first argument to this setting is an integer which is 0 to disable 2253** the writable_schema, positive to enable writable_schema, or negative to 2254** leave the setting unchanged. The second parameter is a pointer to an 2255** integer into which is written 0 or 1 to indicate whether the writable_schema 2256** is enabled or disabled following this call. 2257** </dd> 2258** 2259** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]] 2260** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt> 2261** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates 2262** the legacy behavior of the [ALTER TABLE RENAME] command such it 2263** behaves as it did prior to [version 3.24.0] (2018-06-04). See the 2264** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for 2265** additional information. This feature can also be turned on and off 2266** using the [PRAGMA legacy_alter_table] statement. 2267** </dd> 2268** 2269** [[SQLITE_DBCONFIG_DQS_DML]] 2270** <dt>SQLITE_DBCONFIG_DQS_DML</td> 2271** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates 2272** the legacy [double-quoted string literal] misfeature for DML statements 2273** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The 2274** default value of this setting is determined by the [-DSQLITE_DQS] 2275** compile-time option. 2276** </dd> 2277** 2278** [[SQLITE_DBCONFIG_DQS_DDL]] 2279** <dt>SQLITE_DBCONFIG_DQS_DDL</td> 2280** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates 2281** the legacy [double-quoted string literal] misfeature for DDL statements, 2282** such as CREATE TABLE and CREATE INDEX. The 2283** default value of this setting is determined by the [-DSQLITE_DQS] 2284** compile-time option. 2285** </dd> 2286** 2287** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]] 2288** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td> 2289** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to 2290** assume that database schemas are untainted by malicious content. 2291** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite 2292** takes additional defensive steps to protect the application from harm 2293** including: 2294** <ul> 2295** <li> Prohibit the use of SQL functions inside triggers, views, 2296** CHECK constraints, DEFAULT clauses, expression indexes, 2297** partial indexes, or generated columns 2298** unless those functions are tagged with [SQLITE_INNOCUOUS]. 2299** <li> Prohibit the use of virtual tables inside of triggers or views 2300** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS]. 2301** </ul> 2302** This setting defaults to "on" for legacy compatibility, however 2303** all applications are advised to turn it off if possible. This setting 2304** can also be controlled using the [PRAGMA trusted_schema] statement. 2305** </dd> 2306** 2307** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]] 2308** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td> 2309** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates 2310** the legacy file format flag. When activated, this flag causes all newly 2311** created database file to have a schema format version number (the 4-byte 2312** integer found at offset 44 into the database header) of 1. This in turn 2313** means that the resulting database file will be readable and writable by 2314** any SQLite version back to 3.0.0 ([dateof:3.0.0]). Without this setting, 2315** newly created databases are generally not understandable by SQLite versions 2316** prior to 3.3.0 ([dateof:3.3.0]). As these words are written, there 2317** is now scarcely any need to generated database files that are compatible 2318** all the way back to version 3.0.0, and so this setting is of little 2319** practical use, but is provided so that SQLite can continue to claim the 2320** ability to generate new database files that are compatible with version 2321** 3.0.0. 2322** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on, 2323** the [VACUUM] command will fail with an obscure error when attempting to 2324** process a table with generated columns and a descending index. This is 2325** not considered a bug since SQLite versions 3.3.0 and earlier do not support 2326** either generated columns or decending indexes. 2327** </dd> 2328** </dl> 2329*/ 2330#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2331#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2332#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2333#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2334#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2335#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2336#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2337#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2338#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2339#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */ 2340#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */ 2341#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */ 2342#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */ 2343#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */ 2344#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */ 2345#define SQLITE_DBCONFIG_ENABLE_VIEW 1015 /* int int* */ 2346#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT 1016 /* int int* */ 2347#define SQLITE_DBCONFIG_TRUSTED_SCHEMA 1017 /* int int* */ 2348#define SQLITE_DBCONFIG_MAX 1017 /* Largest DBCONFIG */ 2349 2350/* 2351** CAPI3REF: Enable Or Disable Extended Result Codes 2352** METHOD: sqlite3 2353** 2354** ^The sqlite3_extended_result_codes() routine enables or disables the 2355** [extended result codes] feature of SQLite. ^The extended result 2356** codes are disabled by default for historical compatibility. 2357*/ 2358int sqlite3_extended_result_codes(sqlite3*, int onoff); 2359 2360/* 2361** CAPI3REF: Last Insert Rowid 2362** METHOD: sqlite3 2363** 2364** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2365** has a unique 64-bit signed 2366** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2367** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2368** names are not also used by explicitly declared columns. ^If 2369** the table has a column of type [INTEGER PRIMARY KEY] then that column 2370** is another alias for the rowid. 2371** 2372** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2373** the most recent successful [INSERT] into a rowid table or [virtual table] 2374** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2375** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2376** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2377** zero. 2378** 2379** As well as being set automatically as rows are inserted into database 2380** tables, the value returned by this function may be set explicitly by 2381** [sqlite3_set_last_insert_rowid()] 2382** 2383** Some virtual table implementations may INSERT rows into rowid tables as 2384** part of committing a transaction (e.g. to flush data accumulated in memory 2385** to disk). In this case subsequent calls to this function return the rowid 2386** associated with these internal INSERT operations, which leads to 2387** unintuitive results. Virtual table implementations that do write to rowid 2388** tables in this way can avoid this problem by restoring the original 2389** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2390** control to the user. 2391** 2392** ^(If an [INSERT] occurs within a trigger then this routine will 2393** return the [rowid] of the inserted row as long as the trigger is 2394** running. Once the trigger program ends, the value returned 2395** by this routine reverts to what it was before the trigger was fired.)^ 2396** 2397** ^An [INSERT] that fails due to a constraint violation is not a 2398** successful [INSERT] and does not change the value returned by this 2399** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2400** and INSERT OR ABORT make no changes to the return value of this 2401** routine when their insertion fails. ^(When INSERT OR REPLACE 2402** encounters a constraint violation, it does not fail. The 2403** INSERT continues to completion after deleting rows that caused 2404** the constraint problem so INSERT OR REPLACE will always change 2405** the return value of this interface.)^ 2406** 2407** ^For the purposes of this routine, an [INSERT] is considered to 2408** be successful even if it is subsequently rolled back. 2409** 2410** This function is accessible to SQL statements via the 2411** [last_insert_rowid() SQL function]. 2412** 2413** If a separate thread performs a new [INSERT] on the same 2414** database connection while the [sqlite3_last_insert_rowid()] 2415** function is running and thus changes the last insert [rowid], 2416** then the value returned by [sqlite3_last_insert_rowid()] is 2417** unpredictable and might not equal either the old or the new 2418** last insert [rowid]. 2419*/ 2420sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2421 2422/* 2423** CAPI3REF: Set the Last Insert Rowid value. 2424** METHOD: sqlite3 2425** 2426** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2427** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2428** without inserting a row into the database. 2429*/ 2430void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2431 2432/* 2433** CAPI3REF: Count The Number Of Rows Modified 2434** METHOD: sqlite3 2435** 2436** ^This function returns the number of rows modified, inserted or 2437** deleted by the most recently completed INSERT, UPDATE or DELETE 2438** statement on the database connection specified by the only parameter. 2439** ^Executing any other type of SQL statement does not modify the value 2440** returned by this function. 2441** 2442** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2443** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2444** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2445** 2446** Changes to a view that are intercepted by 2447** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2448** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2449** DELETE statement run on a view is always zero. Only changes made to real 2450** tables are counted. 2451** 2452** Things are more complicated if the sqlite3_changes() function is 2453** executed while a trigger program is running. This may happen if the 2454** program uses the [changes() SQL function], or if some other callback 2455** function invokes sqlite3_changes() directly. Essentially: 2456** 2457** <ul> 2458** <li> ^(Before entering a trigger program the value returned by 2459** sqlite3_changes() function is saved. After the trigger program 2460** has finished, the original value is restored.)^ 2461** 2462** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2463** statement sets the value returned by sqlite3_changes() 2464** upon completion as normal. Of course, this value will not include 2465** any changes performed by sub-triggers, as the sqlite3_changes() 2466** value will be saved and restored after each sub-trigger has run.)^ 2467** </ul> 2468** 2469** ^This means that if the changes() SQL function (or similar) is used 2470** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2471** returns the value as set when the calling statement began executing. 2472** ^If it is used by the second or subsequent such statement within a trigger 2473** program, the value returned reflects the number of rows modified by the 2474** previous INSERT, UPDATE or DELETE statement within the same trigger. 2475** 2476** If a separate thread makes changes on the same database connection 2477** while [sqlite3_changes()] is running then the value returned 2478** is unpredictable and not meaningful. 2479** 2480** See also: 2481** <ul> 2482** <li> the [sqlite3_total_changes()] interface 2483** <li> the [count_changes pragma] 2484** <li> the [changes() SQL function] 2485** <li> the [data_version pragma] 2486** </ul> 2487*/ 2488int sqlite3_changes(sqlite3*); 2489 2490/* 2491** CAPI3REF: Total Number Of Rows Modified 2492** METHOD: sqlite3 2493** 2494** ^This function returns the total number of rows inserted, modified or 2495** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2496** since the database connection was opened, including those executed as 2497** part of trigger programs. ^Executing any other type of SQL statement 2498** does not affect the value returned by sqlite3_total_changes(). 2499** 2500** ^Changes made as part of [foreign key actions] are included in the 2501** count, but those made as part of REPLACE constraint resolution are 2502** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2503** are not counted. 2504** 2505** The [sqlite3_total_changes(D)] interface only reports the number 2506** of rows that changed due to SQL statement run against database 2507** connection D. Any changes by other database connections are ignored. 2508** To detect changes against a database file from other database 2509** connections use the [PRAGMA data_version] command or the 2510** [SQLITE_FCNTL_DATA_VERSION] [file control]. 2511** 2512** If a separate thread makes changes on the same database connection 2513** while [sqlite3_total_changes()] is running then the value 2514** returned is unpredictable and not meaningful. 2515** 2516** See also: 2517** <ul> 2518** <li> the [sqlite3_changes()] interface 2519** <li> the [count_changes pragma] 2520** <li> the [changes() SQL function] 2521** <li> the [data_version pragma] 2522** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control] 2523** </ul> 2524*/ 2525int sqlite3_total_changes(sqlite3*); 2526 2527/* 2528** CAPI3REF: Interrupt A Long-Running Query 2529** METHOD: sqlite3 2530** 2531** ^This function causes any pending database operation to abort and 2532** return at its earliest opportunity. This routine is typically 2533** called in response to a user action such as pressing "Cancel" 2534** or Ctrl-C where the user wants a long query operation to halt 2535** immediately. 2536** 2537** ^It is safe to call this routine from a thread different from the 2538** thread that is currently running the database operation. But it 2539** is not safe to call this routine with a [database connection] that 2540** is closed or might close before sqlite3_interrupt() returns. 2541** 2542** ^If an SQL operation is very nearly finished at the time when 2543** sqlite3_interrupt() is called, then it might not have an opportunity 2544** to be interrupted and might continue to completion. 2545** 2546** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2547** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2548** that is inside an explicit transaction, then the entire transaction 2549** will be rolled back automatically. 2550** 2551** ^The sqlite3_interrupt(D) call is in effect until all currently running 2552** SQL statements on [database connection] D complete. ^Any new SQL statements 2553** that are started after the sqlite3_interrupt() call and before the 2554** running statement count reaches zero are interrupted as if they had been 2555** running prior to the sqlite3_interrupt() call. ^New SQL statements 2556** that are started after the running statement count reaches zero are 2557** not effected by the sqlite3_interrupt(). 2558** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2559** SQL statements is a no-op and has no effect on SQL statements 2560** that are started after the sqlite3_interrupt() call returns. 2561*/ 2562void sqlite3_interrupt(sqlite3*); 2563 2564/* 2565** CAPI3REF: Determine If An SQL Statement Is Complete 2566** 2567** These routines are useful during command-line input to determine if the 2568** currently entered text seems to form a complete SQL statement or 2569** if additional input is needed before sending the text into 2570** SQLite for parsing. ^These routines return 1 if the input string 2571** appears to be a complete SQL statement. ^A statement is judged to be 2572** complete if it ends with a semicolon token and is not a prefix of a 2573** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2574** string literals or quoted identifier names or comments are not 2575** independent tokens (they are part of the token in which they are 2576** embedded) and thus do not count as a statement terminator. ^Whitespace 2577** and comments that follow the final semicolon are ignored. 2578** 2579** ^These routines return 0 if the statement is incomplete. ^If a 2580** memory allocation fails, then SQLITE_NOMEM is returned. 2581** 2582** ^These routines do not parse the SQL statements thus 2583** will not detect syntactically incorrect SQL. 2584** 2585** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2586** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2587** automatically by sqlite3_complete16(). If that initialization fails, 2588** then the return value from sqlite3_complete16() will be non-zero 2589** regardless of whether or not the input SQL is complete.)^ 2590** 2591** The input to [sqlite3_complete()] must be a zero-terminated 2592** UTF-8 string. 2593** 2594** The input to [sqlite3_complete16()] must be a zero-terminated 2595** UTF-16 string in native byte order. 2596*/ 2597int sqlite3_complete(const char *sql); 2598int sqlite3_complete16(const void *sql); 2599 2600/* 2601** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2602** KEYWORDS: {busy-handler callback} {busy handler} 2603** METHOD: sqlite3 2604** 2605** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2606** that might be invoked with argument P whenever 2607** an attempt is made to access a database table associated with 2608** [database connection] D when another thread 2609** or process has the table locked. 2610** The sqlite3_busy_handler() interface is used to implement 2611** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2612** 2613** ^If the busy callback is NULL, then [SQLITE_BUSY] 2614** is returned immediately upon encountering the lock. ^If the busy callback 2615** is not NULL, then the callback might be invoked with two arguments. 2616** 2617** ^The first argument to the busy handler is a copy of the void* pointer which 2618** is the third argument to sqlite3_busy_handler(). ^The second argument to 2619** the busy handler callback is the number of times that the busy handler has 2620** been invoked previously for the same locking event. ^If the 2621** busy callback returns 0, then no additional attempts are made to 2622** access the database and [SQLITE_BUSY] is returned 2623** to the application. 2624** ^If the callback returns non-zero, then another attempt 2625** is made to access the database and the cycle repeats. 2626** 2627** The presence of a busy handler does not guarantee that it will be invoked 2628** when there is lock contention. ^If SQLite determines that invoking the busy 2629** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2630** to the application instead of invoking the 2631** busy handler. 2632** Consider a scenario where one process is holding a read lock that 2633** it is trying to promote to a reserved lock and 2634** a second process is holding a reserved lock that it is trying 2635** to promote to an exclusive lock. The first process cannot proceed 2636** because it is blocked by the second and the second process cannot 2637** proceed because it is blocked by the first. If both processes 2638** invoke the busy handlers, neither will make any progress. Therefore, 2639** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2640** will induce the first process to release its read lock and allow 2641** the second process to proceed. 2642** 2643** ^The default busy callback is NULL. 2644** 2645** ^(There can only be a single busy handler defined for each 2646** [database connection]. Setting a new busy handler clears any 2647** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2648** or evaluating [PRAGMA busy_timeout=N] will change the 2649** busy handler and thus clear any previously set busy handler. 2650** 2651** The busy callback should not take any actions which modify the 2652** database connection that invoked the busy handler. In other words, 2653** the busy handler is not reentrant. Any such actions 2654** result in undefined behavior. 2655** 2656** A busy handler must not close the database connection 2657** or [prepared statement] that invoked the busy handler. 2658*/ 2659int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2660 2661/* 2662** CAPI3REF: Set A Busy Timeout 2663** METHOD: sqlite3 2664** 2665** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2666** for a specified amount of time when a table is locked. ^The handler 2667** will sleep multiple times until at least "ms" milliseconds of sleeping 2668** have accumulated. ^After at least "ms" milliseconds of sleeping, 2669** the handler returns 0 which causes [sqlite3_step()] to return 2670** [SQLITE_BUSY]. 2671** 2672** ^Calling this routine with an argument less than or equal to zero 2673** turns off all busy handlers. 2674** 2675** ^(There can only be a single busy handler for a particular 2676** [database connection] at any given moment. If another busy handler 2677** was defined (using [sqlite3_busy_handler()]) prior to calling 2678** this routine, that other busy handler is cleared.)^ 2679** 2680** See also: [PRAGMA busy_timeout] 2681*/ 2682int sqlite3_busy_timeout(sqlite3*, int ms); 2683 2684/* 2685** CAPI3REF: Convenience Routines For Running Queries 2686** METHOD: sqlite3 2687** 2688** This is a legacy interface that is preserved for backwards compatibility. 2689** Use of this interface is not recommended. 2690** 2691** Definition: A <b>result table</b> is memory data structure created by the 2692** [sqlite3_get_table()] interface. A result table records the 2693** complete query results from one or more queries. 2694** 2695** The table conceptually has a number of rows and columns. But 2696** these numbers are not part of the result table itself. These 2697** numbers are obtained separately. Let N be the number of rows 2698** and M be the number of columns. 2699** 2700** A result table is an array of pointers to zero-terminated UTF-8 strings. 2701** There are (N+1)*M elements in the array. The first M pointers point 2702** to zero-terminated strings that contain the names of the columns. 2703** The remaining entries all point to query results. NULL values result 2704** in NULL pointers. All other values are in their UTF-8 zero-terminated 2705** string representation as returned by [sqlite3_column_text()]. 2706** 2707** A result table might consist of one or more memory allocations. 2708** It is not safe to pass a result table directly to [sqlite3_free()]. 2709** A result table should be deallocated using [sqlite3_free_table()]. 2710** 2711** ^(As an example of the result table format, suppose a query result 2712** is as follows: 2713** 2714** <blockquote><pre> 2715** Name | Age 2716** ----------------------- 2717** Alice | 43 2718** Bob | 28 2719** Cindy | 21 2720** </pre></blockquote> 2721** 2722** There are two columns (M==2) and three rows (N==3). Thus the 2723** result table has 8 entries. Suppose the result table is stored 2724** in an array named azResult. Then azResult holds this content: 2725** 2726** <blockquote><pre> 2727** azResult[0] = "Name"; 2728** azResult[1] = "Age"; 2729** azResult[2] = "Alice"; 2730** azResult[3] = "43"; 2731** azResult[4] = "Bob"; 2732** azResult[5] = "28"; 2733** azResult[6] = "Cindy"; 2734** azResult[7] = "21"; 2735** </pre></blockquote>)^ 2736** 2737** ^The sqlite3_get_table() function evaluates one or more 2738** semicolon-separated SQL statements in the zero-terminated UTF-8 2739** string of its 2nd parameter and returns a result table to the 2740** pointer given in its 3rd parameter. 2741** 2742** After the application has finished with the result from sqlite3_get_table(), 2743** it must pass the result table pointer to sqlite3_free_table() in order to 2744** release the memory that was malloced. Because of the way the 2745** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2746** function must not try to call [sqlite3_free()] directly. Only 2747** [sqlite3_free_table()] is able to release the memory properly and safely. 2748** 2749** The sqlite3_get_table() interface is implemented as a wrapper around 2750** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2751** to any internal data structures of SQLite. It uses only the public 2752** interface defined here. As a consequence, errors that occur in the 2753** wrapper layer outside of the internal [sqlite3_exec()] call are not 2754** reflected in subsequent calls to [sqlite3_errcode()] or 2755** [sqlite3_errmsg()]. 2756*/ 2757int sqlite3_get_table( 2758 sqlite3 *db, /* An open database */ 2759 const char *zSql, /* SQL to be evaluated */ 2760 char ***pazResult, /* Results of the query */ 2761 int *pnRow, /* Number of result rows written here */ 2762 int *pnColumn, /* Number of result columns written here */ 2763 char **pzErrmsg /* Error msg written here */ 2764); 2765void sqlite3_free_table(char **result); 2766 2767/* 2768** CAPI3REF: Formatted String Printing Functions 2769** 2770** These routines are work-alikes of the "printf()" family of functions 2771** from the standard C library. 2772** These routines understand most of the common formatting options from 2773** the standard library printf() 2774** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2775** See the [built-in printf()] documentation for details. 2776** 2777** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2778** results into memory obtained from [sqlite3_malloc64()]. 2779** The strings returned by these two routines should be 2780** released by [sqlite3_free()]. ^Both routines return a 2781** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2782** memory to hold the resulting string. 2783** 2784** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2785** the standard C library. The result is written into the 2786** buffer supplied as the second parameter whose size is given by 2787** the first parameter. Note that the order of the 2788** first two parameters is reversed from snprintf().)^ This is an 2789** historical accident that cannot be fixed without breaking 2790** backwards compatibility. ^(Note also that sqlite3_snprintf() 2791** returns a pointer to its buffer instead of the number of 2792** characters actually written into the buffer.)^ We admit that 2793** the number of characters written would be a more useful return 2794** value but we cannot change the implementation of sqlite3_snprintf() 2795** now without breaking compatibility. 2796** 2797** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2798** guarantees that the buffer is always zero-terminated. ^The first 2799** parameter "n" is the total size of the buffer, including space for 2800** the zero terminator. So the longest string that can be completely 2801** written will be n-1 characters. 2802** 2803** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2804** 2805** See also: [built-in printf()], [printf() SQL function] 2806*/ 2807char *sqlite3_mprintf(const char*,...); 2808char *sqlite3_vmprintf(const char*, va_list); 2809char *sqlite3_snprintf(int,char*,const char*, ...); 2810char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2811 2812/* 2813** CAPI3REF: Memory Allocation Subsystem 2814** 2815** The SQLite core uses these three routines for all of its own 2816** internal memory allocation needs. "Core" in the previous sentence 2817** does not include operating-system specific [VFS] implementation. The 2818** Windows VFS uses native malloc() and free() for some operations. 2819** 2820** ^The sqlite3_malloc() routine returns a pointer to a block 2821** of memory at least N bytes in length, where N is the parameter. 2822** ^If sqlite3_malloc() is unable to obtain sufficient free 2823** memory, it returns a NULL pointer. ^If the parameter N to 2824** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2825** a NULL pointer. 2826** 2827** ^The sqlite3_malloc64(N) routine works just like 2828** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2829** of a signed 32-bit integer. 2830** 2831** ^Calling sqlite3_free() with a pointer previously returned 2832** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2833** that it might be reused. ^The sqlite3_free() routine is 2834** a no-op if is called with a NULL pointer. Passing a NULL pointer 2835** to sqlite3_free() is harmless. After being freed, memory 2836** should neither be read nor written. Even reading previously freed 2837** memory might result in a segmentation fault or other severe error. 2838** Memory corruption, a segmentation fault, or other severe error 2839** might result if sqlite3_free() is called with a non-NULL pointer that 2840** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2841** 2842** ^The sqlite3_realloc(X,N) interface attempts to resize a 2843** prior memory allocation X to be at least N bytes. 2844** ^If the X parameter to sqlite3_realloc(X,N) 2845** is a NULL pointer then its behavior is identical to calling 2846** sqlite3_malloc(N). 2847** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2848** negative then the behavior is exactly the same as calling 2849** sqlite3_free(X). 2850** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2851** of at least N bytes in size or NULL if insufficient memory is available. 2852** ^If M is the size of the prior allocation, then min(N,M) bytes 2853** of the prior allocation are copied into the beginning of buffer returned 2854** by sqlite3_realloc(X,N) and the prior allocation is freed. 2855** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2856** prior allocation is not freed. 2857** 2858** ^The sqlite3_realloc64(X,N) interfaces works the same as 2859** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2860** of a 32-bit signed integer. 2861** 2862** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2863** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2864** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2865** ^The value returned by sqlite3_msize(X) might be larger than the number 2866** of bytes requested when X was allocated. ^If X is a NULL pointer then 2867** sqlite3_msize(X) returns zero. If X points to something that is not 2868** the beginning of memory allocation, or if it points to a formerly 2869** valid memory allocation that has now been freed, then the behavior 2870** of sqlite3_msize(X) is undefined and possibly harmful. 2871** 2872** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2873** sqlite3_malloc64(), and sqlite3_realloc64() 2874** is always aligned to at least an 8 byte boundary, or to a 2875** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2876** option is used. 2877** 2878** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2879** must be either NULL or else pointers obtained from a prior 2880** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2881** not yet been released. 2882** 2883** The application must not read or write any part of 2884** a block of memory after it has been released using 2885** [sqlite3_free()] or [sqlite3_realloc()]. 2886*/ 2887void *sqlite3_malloc(int); 2888void *sqlite3_malloc64(sqlite3_uint64); 2889void *sqlite3_realloc(void*, int); 2890void *sqlite3_realloc64(void*, sqlite3_uint64); 2891void sqlite3_free(void*); 2892sqlite3_uint64 sqlite3_msize(void*); 2893 2894/* 2895** CAPI3REF: Memory Allocator Statistics 2896** 2897** SQLite provides these two interfaces for reporting on the status 2898** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2899** routines, which form the built-in memory allocation subsystem. 2900** 2901** ^The [sqlite3_memory_used()] routine returns the number of bytes 2902** of memory currently outstanding (malloced but not freed). 2903** ^The [sqlite3_memory_highwater()] routine returns the maximum 2904** value of [sqlite3_memory_used()] since the high-water mark 2905** was last reset. ^The values returned by [sqlite3_memory_used()] and 2906** [sqlite3_memory_highwater()] include any overhead 2907** added by SQLite in its implementation of [sqlite3_malloc()], 2908** but not overhead added by the any underlying system library 2909** routines that [sqlite3_malloc()] may call. 2910** 2911** ^The memory high-water mark is reset to the current value of 2912** [sqlite3_memory_used()] if and only if the parameter to 2913** [sqlite3_memory_highwater()] is true. ^The value returned 2914** by [sqlite3_memory_highwater(1)] is the high-water mark 2915** prior to the reset. 2916*/ 2917sqlite3_int64 sqlite3_memory_used(void); 2918sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2919 2920/* 2921** CAPI3REF: Pseudo-Random Number Generator 2922** 2923** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2924** select random [ROWID | ROWIDs] when inserting new records into a table that 2925** already uses the largest possible [ROWID]. The PRNG is also used for 2926** the built-in random() and randomblob() SQL functions. This interface allows 2927** applications to access the same PRNG for other purposes. 2928** 2929** ^A call to this routine stores N bytes of randomness into buffer P. 2930** ^The P parameter can be a NULL pointer. 2931** 2932** ^If this routine has not been previously called or if the previous 2933** call had N less than one or a NULL pointer for P, then the PRNG is 2934** seeded using randomness obtained from the xRandomness method of 2935** the default [sqlite3_vfs] object. 2936** ^If the previous call to this routine had an N of 1 or more and a 2937** non-NULL P then the pseudo-randomness is generated 2938** internally and without recourse to the [sqlite3_vfs] xRandomness 2939** method. 2940*/ 2941void sqlite3_randomness(int N, void *P); 2942 2943/* 2944** CAPI3REF: Compile-Time Authorization Callbacks 2945** METHOD: sqlite3 2946** KEYWORDS: {authorizer callback} 2947** 2948** ^This routine registers an authorizer callback with a particular 2949** [database connection], supplied in the first argument. 2950** ^The authorizer callback is invoked as SQL statements are being compiled 2951** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2952** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2953** and [sqlite3_prepare16_v3()]. ^At various 2954** points during the compilation process, as logic is being created 2955** to perform various actions, the authorizer callback is invoked to 2956** see if those actions are allowed. ^The authorizer callback should 2957** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2958** specific action but allow the SQL statement to continue to be 2959** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2960** rejected with an error. ^If the authorizer callback returns 2961** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2962** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2963** the authorizer will fail with an error message. 2964** 2965** When the callback returns [SQLITE_OK], that means the operation 2966** requested is ok. ^When the callback returns [SQLITE_DENY], the 2967** [sqlite3_prepare_v2()] or equivalent call that triggered the 2968** authorizer will fail with an error message explaining that 2969** access is denied. 2970** 2971** ^The first parameter to the authorizer callback is a copy of the third 2972** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2973** to the callback is an integer [SQLITE_COPY | action code] that specifies 2974** the particular action to be authorized. ^The third through sixth parameters 2975** to the callback are either NULL pointers or zero-terminated strings 2976** that contain additional details about the action to be authorized. 2977** Applications must always be prepared to encounter a NULL pointer in any 2978** of the third through the sixth parameters of the authorization callback. 2979** 2980** ^If the action code is [SQLITE_READ] 2981** and the callback returns [SQLITE_IGNORE] then the 2982** [prepared statement] statement is constructed to substitute 2983** a NULL value in place of the table column that would have 2984** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2985** return can be used to deny an untrusted user access to individual 2986** columns of a table. 2987** ^When a table is referenced by a [SELECT] but no column values are 2988** extracted from that table (for example in a query like 2989** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2990** is invoked once for that table with a column name that is an empty string. 2991** ^If the action code is [SQLITE_DELETE] and the callback returns 2992** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2993** [truncate optimization] is disabled and all rows are deleted individually. 2994** 2995** An authorizer is used when [sqlite3_prepare | preparing] 2996** SQL statements from an untrusted source, to ensure that the SQL statements 2997** do not try to access data they are not allowed to see, or that they do not 2998** try to execute malicious statements that damage the database. For 2999** example, an application may allow a user to enter arbitrary 3000** SQL queries for evaluation by a database. But the application does 3001** not want the user to be able to make arbitrary changes to the 3002** database. An authorizer could then be put in place while the 3003** user-entered SQL is being [sqlite3_prepare | prepared] that 3004** disallows everything except [SELECT] statements. 3005** 3006** Applications that need to process SQL from untrusted sources 3007** might also consider lowering resource limits using [sqlite3_limit()] 3008** and limiting database size using the [max_page_count] [PRAGMA] 3009** in addition to using an authorizer. 3010** 3011** ^(Only a single authorizer can be in place on a database connection 3012** at a time. Each call to sqlite3_set_authorizer overrides the 3013** previous call.)^ ^Disable the authorizer by installing a NULL callback. 3014** The authorizer is disabled by default. 3015** 3016** The authorizer callback must not do anything that will modify 3017** the database connection that invoked the authorizer callback. 3018** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3019** database connections for the meaning of "modify" in this paragraph. 3020** 3021** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 3022** statement might be re-prepared during [sqlite3_step()] due to a 3023** schema change. Hence, the application should ensure that the 3024** correct authorizer callback remains in place during the [sqlite3_step()]. 3025** 3026** ^Note that the authorizer callback is invoked only during 3027** [sqlite3_prepare()] or its variants. Authorization is not 3028** performed during statement evaluation in [sqlite3_step()], unless 3029** as stated in the previous paragraph, sqlite3_step() invokes 3030** sqlite3_prepare_v2() to reprepare a statement after a schema change. 3031*/ 3032int sqlite3_set_authorizer( 3033 sqlite3*, 3034 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 3035 void *pUserData 3036); 3037 3038/* 3039** CAPI3REF: Authorizer Return Codes 3040** 3041** The [sqlite3_set_authorizer | authorizer callback function] must 3042** return either [SQLITE_OK] or one of these two constants in order 3043** to signal SQLite whether or not the action is permitted. See the 3044** [sqlite3_set_authorizer | authorizer documentation] for additional 3045** information. 3046** 3047** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 3048** returned from the [sqlite3_vtab_on_conflict()] interface. 3049*/ 3050#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 3051#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 3052 3053/* 3054** CAPI3REF: Authorizer Action Codes 3055** 3056** The [sqlite3_set_authorizer()] interface registers a callback function 3057** that is invoked to authorize certain SQL statement actions. The 3058** second parameter to the callback is an integer code that specifies 3059** what action is being authorized. These are the integer action codes that 3060** the authorizer callback may be passed. 3061** 3062** These action code values signify what kind of operation is to be 3063** authorized. The 3rd and 4th parameters to the authorization 3064** callback function will be parameters or NULL depending on which of these 3065** codes is used as the second parameter. ^(The 5th parameter to the 3066** authorizer callback is the name of the database ("main", "temp", 3067** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 3068** is the name of the inner-most trigger or view that is responsible for 3069** the access attempt or NULL if this access attempt is directly from 3070** top-level SQL code. 3071*/ 3072/******************************************* 3rd ************ 4th ***********/ 3073#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 3074#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 3075#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 3076#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 3077#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 3078#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 3079#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 3080#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 3081#define SQLITE_DELETE 9 /* Table Name NULL */ 3082#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 3083#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 3084#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 3085#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 3086#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 3087#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 3088#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 3089#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 3090#define SQLITE_INSERT 18 /* Table Name NULL */ 3091#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 3092#define SQLITE_READ 20 /* Table Name Column Name */ 3093#define SQLITE_SELECT 21 /* NULL NULL */ 3094#define SQLITE_TRANSACTION 22 /* Operation NULL */ 3095#define SQLITE_UPDATE 23 /* Table Name Column Name */ 3096#define SQLITE_ATTACH 24 /* Filename NULL */ 3097#define SQLITE_DETACH 25 /* Database Name NULL */ 3098#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 3099#define SQLITE_REINDEX 27 /* Index Name NULL */ 3100#define SQLITE_ANALYZE 28 /* Table Name NULL */ 3101#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 3102#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 3103#define SQLITE_FUNCTION 31 /* NULL Function Name */ 3104#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 3105#define SQLITE_COPY 0 /* No longer used */ 3106#define SQLITE_RECURSIVE 33 /* NULL NULL */ 3107 3108/* 3109** CAPI3REF: Tracing And Profiling Functions 3110** METHOD: sqlite3 3111** 3112** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 3113** instead of the routines described here. 3114** 3115** These routines register callback functions that can be used for 3116** tracing and profiling the execution of SQL statements. 3117** 3118** ^The callback function registered by sqlite3_trace() is invoked at 3119** various times when an SQL statement is being run by [sqlite3_step()]. 3120** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 3121** SQL statement text as the statement first begins executing. 3122** ^(Additional sqlite3_trace() callbacks might occur 3123** as each triggered subprogram is entered. The callbacks for triggers 3124** contain a UTF-8 SQL comment that identifies the trigger.)^ 3125** 3126** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 3127** the length of [bound parameter] expansion in the output of sqlite3_trace(). 3128** 3129** ^The callback function registered by sqlite3_profile() is invoked 3130** as each SQL statement finishes. ^The profile callback contains 3131** the original statement text and an estimate of wall-clock time 3132** of how long that statement took to run. ^The profile callback 3133** time is in units of nanoseconds, however the current implementation 3134** is only capable of millisecond resolution so the six least significant 3135** digits in the time are meaningless. Future versions of SQLite 3136** might provide greater resolution on the profiler callback. Invoking 3137** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the 3138** profile callback. 3139*/ 3140SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 3141 void(*xTrace)(void*,const char*), void*); 3142SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 3143 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 3144 3145/* 3146** CAPI3REF: SQL Trace Event Codes 3147** KEYWORDS: SQLITE_TRACE 3148** 3149** These constants identify classes of events that can be monitored 3150** using the [sqlite3_trace_v2()] tracing logic. The M argument 3151** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 3152** the following constants. ^The first argument to the trace callback 3153** is one of the following constants. 3154** 3155** New tracing constants may be added in future releases. 3156** 3157** ^A trace callback has four arguments: xCallback(T,C,P,X). 3158** ^The T argument is one of the integer type codes above. 3159** ^The C argument is a copy of the context pointer passed in as the 3160** fourth argument to [sqlite3_trace_v2()]. 3161** The P and X arguments are pointers whose meanings depend on T. 3162** 3163** <dl> 3164** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 3165** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 3166** first begins running and possibly at other times during the 3167** execution of the prepared statement, such as at the start of each 3168** trigger subprogram. ^The P argument is a pointer to the 3169** [prepared statement]. ^The X argument is a pointer to a string which 3170** is the unexpanded SQL text of the prepared statement or an SQL comment 3171** that indicates the invocation of a trigger. ^The callback can compute 3172** the same text that would have been returned by the legacy [sqlite3_trace()] 3173** interface by using the X argument when X begins with "--" and invoking 3174** [sqlite3_expanded_sql(P)] otherwise. 3175** 3176** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 3177** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 3178** information as is provided by the [sqlite3_profile()] callback. 3179** ^The P argument is a pointer to the [prepared statement] and the 3180** X argument points to a 64-bit integer which is the estimated of 3181** the number of nanosecond that the prepared statement took to run. 3182** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 3183** 3184** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 3185** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 3186** statement generates a single row of result. 3187** ^The P argument is a pointer to the [prepared statement] and the 3188** X argument is unused. 3189** 3190** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 3191** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 3192** connection closes. 3193** ^The P argument is a pointer to the [database connection] object 3194** and the X argument is unused. 3195** </dl> 3196*/ 3197#define SQLITE_TRACE_STMT 0x01 3198#define SQLITE_TRACE_PROFILE 0x02 3199#define SQLITE_TRACE_ROW 0x04 3200#define SQLITE_TRACE_CLOSE 0x08 3201 3202/* 3203** CAPI3REF: SQL Trace Hook 3204** METHOD: sqlite3 3205** 3206** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3207** function X against [database connection] D, using property mask M 3208** and context pointer P. ^If the X callback is 3209** NULL or if the M mask is zero, then tracing is disabled. The 3210** M argument should be the bitwise OR-ed combination of 3211** zero or more [SQLITE_TRACE] constants. 3212** 3213** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3214** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3215** 3216** ^The X callback is invoked whenever any of the events identified by 3217** mask M occur. ^The integer return value from the callback is currently 3218** ignored, though this may change in future releases. Callback 3219** implementations should return zero to ensure future compatibility. 3220** 3221** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3222** ^The T argument is one of the [SQLITE_TRACE] 3223** constants to indicate why the callback was invoked. 3224** ^The C argument is a copy of the context pointer. 3225** The P and X arguments are pointers whose meanings depend on T. 3226** 3227** The sqlite3_trace_v2() interface is intended to replace the legacy 3228** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3229** are deprecated. 3230*/ 3231int sqlite3_trace_v2( 3232 sqlite3*, 3233 unsigned uMask, 3234 int(*xCallback)(unsigned,void*,void*,void*), 3235 void *pCtx 3236); 3237 3238/* 3239** CAPI3REF: Query Progress Callbacks 3240** METHOD: sqlite3 3241** 3242** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3243** function X to be invoked periodically during long running calls to 3244** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3245** database connection D. An example use for this 3246** interface is to keep a GUI updated during a large query. 3247** 3248** ^The parameter P is passed through as the only parameter to the 3249** callback function X. ^The parameter N is the approximate number of 3250** [virtual machine instructions] that are evaluated between successive 3251** invocations of the callback X. ^If N is less than one then the progress 3252** handler is disabled. 3253** 3254** ^Only a single progress handler may be defined at one time per 3255** [database connection]; setting a new progress handler cancels the 3256** old one. ^Setting parameter X to NULL disables the progress handler. 3257** ^The progress handler is also disabled by setting N to a value less 3258** than 1. 3259** 3260** ^If the progress callback returns non-zero, the operation is 3261** interrupted. This feature can be used to implement a 3262** "Cancel" button on a GUI progress dialog box. 3263** 3264** The progress handler callback must not do anything that will modify 3265** the database connection that invoked the progress handler. 3266** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3267** database connections for the meaning of "modify" in this paragraph. 3268** 3269*/ 3270void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3271 3272/* 3273** CAPI3REF: Opening A New Database Connection 3274** CONSTRUCTOR: sqlite3 3275** 3276** ^These routines open an SQLite database file as specified by the 3277** filename argument. ^The filename argument is interpreted as UTF-8 for 3278** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3279** order for sqlite3_open16(). ^(A [database connection] handle is usually 3280** returned in *ppDb, even if an error occurs. The only exception is that 3281** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3282** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3283** object.)^ ^(If the database is opened (and/or created) successfully, then 3284** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3285** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3286** an English language description of the error following a failure of any 3287** of the sqlite3_open() routines. 3288** 3289** ^The default encoding will be UTF-8 for databases created using 3290** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3291** created using sqlite3_open16() will be UTF-16 in the native byte order. 3292** 3293** Whether or not an error occurs when it is opened, resources 3294** associated with the [database connection] handle should be released by 3295** passing it to [sqlite3_close()] when it is no longer required. 3296** 3297** The sqlite3_open_v2() interface works like sqlite3_open() 3298** except that it accepts two additional parameters for additional control 3299** over the new database connection. ^(The flags parameter to 3300** sqlite3_open_v2() must include, at a minimum, one of the following 3301** three flag combinations:)^ 3302** 3303** <dl> 3304** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3305** <dd>The database is opened in read-only mode. If the database does not 3306** already exist, an error is returned.</dd>)^ 3307** 3308** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3309** <dd>The database is opened for reading and writing if possible, or reading 3310** only if the file is write protected by the operating system. In either 3311** case the database must already exist, otherwise an error is returned.</dd>)^ 3312** 3313** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3314** <dd>The database is opened for reading and writing, and is created if 3315** it does not already exist. This is the behavior that is always used for 3316** sqlite3_open() and sqlite3_open16().</dd>)^ 3317** </dl> 3318** 3319** In addition to the required flags, the following optional flags are 3320** also supported: 3321** 3322** <dl> 3323** ^(<dt>[SQLITE_OPEN_URI]</dt> 3324** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^ 3325** 3326** ^(<dt>[SQLITE_OPEN_MEMORY]</dt> 3327** <dd>The database will be opened as an in-memory database. The database 3328** is named by the "filename" argument for the purposes of cache-sharing, 3329** if shared cache mode is enabled, but the "filename" is otherwise ignored. 3330** </dd>)^ 3331** 3332** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt> 3333** <dd>The new database connection will use the "multi-thread" 3334** [threading mode].)^ This means that separate threads are allowed 3335** to use SQLite at the same time, as long as each thread is using 3336** a different [database connection]. 3337** 3338** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt> 3339** <dd>The new database connection will use the "serialized" 3340** [threading mode].)^ This means the multiple threads can safely 3341** attempt to use the same database connection at the same time. 3342** (Mutexes will block any actual concurrency, but in this mode 3343** there is no harm in trying.) 3344** 3345** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt> 3346** <dd>The database is opened [shared cache] enabled, overriding 3347** the default shared cache setting provided by 3348** [sqlite3_enable_shared_cache()].)^ 3349** 3350** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt> 3351** <dd>The database is opened [shared cache] disabled, overriding 3352** the default shared cache setting provided by 3353** [sqlite3_enable_shared_cache()].)^ 3354** 3355** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt> 3356** <dd>The database filename is not allowed to be a symbolic link</dd> 3357** </dl>)^ 3358** 3359** If the 3rd parameter to sqlite3_open_v2() is not one of the 3360** required combinations shown above optionally combined with other 3361** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3362** then the behavior is undefined. 3363** 3364** ^The fourth parameter to sqlite3_open_v2() is the name of the 3365** [sqlite3_vfs] object that defines the operating system interface that 3366** the new database connection should use. ^If the fourth parameter is 3367** a NULL pointer then the default [sqlite3_vfs] object is used. 3368** 3369** ^If the filename is ":memory:", then a private, temporary in-memory database 3370** is created for the connection. ^This in-memory database will vanish when 3371** the database connection is closed. Future versions of SQLite might 3372** make use of additional special filenames that begin with the ":" character. 3373** It is recommended that when a database filename actually does begin with 3374** a ":" character you should prefix the filename with a pathname such as 3375** "./" to avoid ambiguity. 3376** 3377** ^If the filename is an empty string, then a private, temporary 3378** on-disk database will be created. ^This private database will be 3379** automatically deleted as soon as the database connection is closed. 3380** 3381** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3382** 3383** ^If [URI filename] interpretation is enabled, and the filename argument 3384** begins with "file:", then the filename is interpreted as a URI. ^URI 3385** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3386** set in the third argument to sqlite3_open_v2(), or if it has 3387** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3388** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3389** URI filename interpretation is turned off 3390** by default, but future releases of SQLite might enable URI filename 3391** interpretation by default. See "[URI filenames]" for additional 3392** information. 3393** 3394** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3395** authority, then it must be either an empty string or the string 3396** "localhost". ^If the authority is not an empty string or "localhost", an 3397** error is returned to the caller. ^The fragment component of a URI, if 3398** present, is ignored. 3399** 3400** ^SQLite uses the path component of the URI as the name of the disk file 3401** which contains the database. ^If the path begins with a '/' character, 3402** then it is interpreted as an absolute path. ^If the path does not begin 3403** with a '/' (meaning that the authority section is omitted from the URI) 3404** then the path is interpreted as a relative path. 3405** ^(On windows, the first component of an absolute path 3406** is a drive specification (e.g. "C:").)^ 3407** 3408** [[core URI query parameters]] 3409** The query component of a URI may contain parameters that are interpreted 3410** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3411** SQLite and its built-in [VFSes] interpret the 3412** following query parameters: 3413** 3414** <ul> 3415** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3416** a VFS object that provides the operating system interface that should 3417** be used to access the database file on disk. ^If this option is set to 3418** an empty string the default VFS object is used. ^Specifying an unknown 3419** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3420** present, then the VFS specified by the option takes precedence over 3421** the value passed as the fourth parameter to sqlite3_open_v2(). 3422** 3423** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3424** "rwc", or "memory". Attempting to set it to any other value is 3425** an error)^. 3426** ^If "ro" is specified, then the database is opened for read-only 3427** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3428** third argument to sqlite3_open_v2(). ^If the mode option is set to 3429** "rw", then the database is opened for read-write (but not create) 3430** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3431** been set. ^Value "rwc" is equivalent to setting both 3432** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3433** set to "memory" then a pure [in-memory database] that never reads 3434** or writes from disk is used. ^It is an error to specify a value for 3435** the mode parameter that is less restrictive than that specified by 3436** the flags passed in the third parameter to sqlite3_open_v2(). 3437** 3438** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3439** "private". ^Setting it to "shared" is equivalent to setting the 3440** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3441** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3442** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3443** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3444** a URI filename, its value overrides any behavior requested by setting 3445** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3446** 3447** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3448** [powersafe overwrite] property does or does not apply to the 3449** storage media on which the database file resides. 3450** 3451** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3452** which if set disables file locking in rollback journal modes. This 3453** is useful for accessing a database on a filesystem that does not 3454** support locking. Caution: Database corruption might result if two 3455** or more processes write to the same database and any one of those 3456** processes uses nolock=1. 3457** 3458** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3459** parameter that indicates that the database file is stored on 3460** read-only media. ^When immutable is set, SQLite assumes that the 3461** database file cannot be changed, even by a process with higher 3462** privilege, and so the database is opened read-only and all locking 3463** and change detection is disabled. Caution: Setting the immutable 3464** property on a database file that does in fact change can result 3465** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3466** See also: [SQLITE_IOCAP_IMMUTABLE]. 3467** 3468** </ul> 3469** 3470** ^Specifying an unknown parameter in the query component of a URI is not an 3471** error. Future versions of SQLite might understand additional query 3472** parameters. See "[query parameters with special meaning to SQLite]" for 3473** additional information. 3474** 3475** [[URI filename examples]] <h3>URI filename examples</h3> 3476** 3477** <table border="1" align=center cellpadding=5> 3478** <tr><th> URI filenames <th> Results 3479** <tr><td> file:data.db <td> 3480** Open the file "data.db" in the current directory. 3481** <tr><td> file:/home/fred/data.db<br> 3482** file:///home/fred/data.db <br> 3483** file://localhost/home/fred/data.db <br> <td> 3484** Open the database file "/home/fred/data.db". 3485** <tr><td> file://darkstar/home/fred/data.db <td> 3486** An error. "darkstar" is not a recognized authority. 3487** <tr><td style="white-space:nowrap"> 3488** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3489** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3490** C:. Note that the %20 escaping in this example is not strictly 3491** necessary - space characters can be used literally 3492** in URI filenames. 3493** <tr><td> file:data.db?mode=ro&cache=private <td> 3494** Open file "data.db" in the current directory for read-only access. 3495** Regardless of whether or not shared-cache mode is enabled by 3496** default, use a private cache. 3497** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3498** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3499** that uses dot-files in place of posix advisory locking. 3500** <tr><td> file:data.db?mode=readonly <td> 3501** An error. "readonly" is not a valid option for the "mode" parameter. 3502** </table> 3503** 3504** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3505** query components of a URI. A hexadecimal escape sequence consists of a 3506** percent sign - "%" - followed by exactly two hexadecimal digits 3507** specifying an octet value. ^Before the path or query components of a 3508** URI filename are interpreted, they are encoded using UTF-8 and all 3509** hexadecimal escape sequences replaced by a single byte containing the 3510** corresponding octet. If this process generates an invalid UTF-8 encoding, 3511** the results are undefined. 3512** 3513** <b>Note to Windows users:</b> The encoding used for the filename argument 3514** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3515** codepage is currently defined. Filenames containing international 3516** characters must be converted to UTF-8 prior to passing them into 3517** sqlite3_open() or sqlite3_open_v2(). 3518** 3519** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3520** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3521** features that require the use of temporary files may fail. 3522** 3523** See also: [sqlite3_temp_directory] 3524*/ 3525int sqlite3_open( 3526 const char *filename, /* Database filename (UTF-8) */ 3527 sqlite3 **ppDb /* OUT: SQLite db handle */ 3528); 3529int sqlite3_open16( 3530 const void *filename, /* Database filename (UTF-16) */ 3531 sqlite3 **ppDb /* OUT: SQLite db handle */ 3532); 3533int sqlite3_open_v2( 3534 const char *filename, /* Database filename (UTF-8) */ 3535 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3536 int flags, /* Flags */ 3537 const char *zVfs /* Name of VFS module to use */ 3538); 3539 3540/* 3541** CAPI3REF: Obtain Values For URI Parameters 3542** 3543** These are utility routines, useful to [VFS|custom VFS implementations], 3544** that check if a database file was a URI that contained a specific query 3545** parameter, and if so obtains the value of that query parameter. 3546** 3547** The first parameter to these interfaces (hereafter referred to 3548** as F) must be one of: 3549** <ul> 3550** <li> A database filename pointer created by the SQLite core and 3551** passed into the xOpen() method of a VFS implemention, or 3552** <li> A filename obtained from [sqlite3_db_filename()], or 3553** <li> A new filename constructed using [sqlite3_create_filename()]. 3554** </ul> 3555** If the F parameter is not one of the above, then the behavior is 3556** undefined and probably undesirable. Older versions of SQLite were 3557** more tolerant of invalid F parameters than newer versions. 3558** 3559** If F is a suitable filename (as described in the previous paragraph) 3560** and if P is the name of the query parameter, then 3561** sqlite3_uri_parameter(F,P) returns the value of the P 3562** parameter if it exists or a NULL pointer if P does not appear as a 3563** query parameter on F. If P is a query parameter of F and it 3564** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3565** a pointer to an empty string. 3566** 3567** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3568** parameter and returns true (1) or false (0) according to the value 3569** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3570** value of query parameter P is one of "yes", "true", or "on" in any 3571** case or if the value begins with a non-zero number. The 3572** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3573** query parameter P is one of "no", "false", or "off" in any case or 3574** if the value begins with a numeric zero. If P is not a query 3575** parameter on F or if the value of P does not match any of the 3576** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3577** 3578** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3579** 64-bit signed integer and returns that integer, or D if P does not 3580** exist. If the value of P is something other than an integer, then 3581** zero is returned. 3582** 3583** The sqlite3_uri_key(F,N) returns a pointer to the name (not 3584** the value) of the N-th query parameter for filename F, or a NULL 3585** pointer if N is less than zero or greater than the number of query 3586** parameters minus 1. The N value is zero-based so N should be 0 to obtain 3587** the name of the first query parameter, 1 for the second parameter, and 3588** so forth. 3589** 3590** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3591** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3592** is not a database file pathname pointer that the SQLite core passed 3593** into the xOpen VFS method, then the behavior of this routine is undefined 3594** and probably undesirable. 3595** 3596** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F 3597** parameter can also be the name of a rollback journal file or WAL file 3598** in addition to the main database file. Prior to version 3.31.0, these 3599** routines would only work if F was the name of the main database file. 3600** When the F parameter is the name of the rollback journal or WAL file, 3601** it has access to all the same query parameters as were found on the 3602** main database file. 3603** 3604** See the [URI filename] documentation for additional information. 3605*/ 3606const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3607int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3608sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3609const char *sqlite3_uri_key(const char *zFilename, int N); 3610 3611/* 3612** CAPI3REF: Translate filenames 3613** 3614** These routines are available to [VFS|custom VFS implementations] for 3615** translating filenames between the main database file, the journal file, 3616** and the WAL file. 3617** 3618** If F is the name of an sqlite database file, journal file, or WAL file 3619** passed by the SQLite core into the VFS, then sqlite3_filename_database(F) 3620** returns the name of the corresponding database file. 3621** 3622** If F is the name of an sqlite database file, journal file, or WAL file 3623** passed by the SQLite core into the VFS, or if F is a database filename 3624** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F) 3625** returns the name of the corresponding rollback journal file. 3626** 3627** If F is the name of an sqlite database file, journal file, or WAL file 3628** that was passed by the SQLite core into the VFS, or if F is a database 3629** filename obtained from [sqlite3_db_filename()], then 3630** sqlite3_filename_wal(F) returns the name of the corresponding 3631** WAL file. 3632** 3633** In all of the above, if F is not the name of a database, journal or WAL 3634** filename passed into the VFS from the SQLite core and F is not the 3635** return value from [sqlite3_db_filename()], then the result is 3636** undefined and is likely a memory access violation. 3637*/ 3638const char *sqlite3_filename_database(const char*); 3639const char *sqlite3_filename_journal(const char*); 3640const char *sqlite3_filename_wal(const char*); 3641 3642/* 3643** CAPI3REF: Database File Corresponding To A Journal 3644** 3645** ^If X is the name of a rollback or WAL-mode journal file that is 3646** passed into the xOpen method of [sqlite3_vfs], then 3647** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file] 3648** object that represents the main database file. 3649** 3650** This routine is intended for use in custom [VFS] implementations 3651** only. It is not a general-purpose interface. 3652** The argument sqlite3_file_object(X) must be a filename pointer that 3653** has been passed into [sqlite3_vfs].xOpen method where the 3654** flags parameter to xOpen contains one of the bits 3655** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL]. Any other use 3656** of this routine results in undefined and probably undesirable 3657** behavior. 3658*/ 3659sqlite3_file *sqlite3_database_file_object(const char*); 3660 3661/* 3662** CAPI3REF: Create and Destroy VFS Filenames 3663** 3664** These interfces are provided for use by [VFS shim] implementations and 3665** are not useful outside of that context. 3666** 3667** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of 3668** database filename D with corresponding journal file J and WAL file W and 3669** with N URI parameters key/values pairs in the array P. The result from 3670** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that 3671** is safe to pass to routines like: 3672** <ul> 3673** <li> [sqlite3_uri_parameter()], 3674** <li> [sqlite3_uri_boolean()], 3675** <li> [sqlite3_uri_int64()], 3676** <li> [sqlite3_uri_key()], 3677** <li> [sqlite3_filename_database()], 3678** <li> [sqlite3_filename_journal()], or 3679** <li> [sqlite3_filename_wal()]. 3680** </ul> 3681** If a memory allocation error occurs, sqlite3_create_filename() might 3682** return a NULL pointer. The memory obtained from sqlite3_create_filename(X) 3683** must be released by a corresponding call to sqlite3_free_filename(Y). 3684** 3685** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array 3686** of 2*N pointers to strings. Each pair of pointers in this array corresponds 3687** to a key and value for a query parameter. The P parameter may be a NULL 3688** pointer if N is zero. None of the 2*N pointers in the P array may be 3689** NULL pointers and key pointers should not be empty strings. 3690** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may 3691** be NULL pointers, though they can be empty strings. 3692** 3693** The sqlite3_free_filename(Y) routine releases a memory allocation 3694** previously obtained from sqlite3_create_filename(). Invoking 3695** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op. 3696** 3697** If the Y parameter to sqlite3_free_filename(Y) is anything other 3698** than a NULL pointer or a pointer previously acquired from 3699** sqlite3_create_filename(), then bad things such as heap 3700** corruption or segfaults may occur. The value Y should be 3701** used again after sqlite3_free_filename(Y) has been called. This means 3702** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y, 3703** then the corresponding [sqlite3_module.xClose() method should also be 3704** invoked prior to calling sqlite3_free_filename(Y). 3705*/ 3706char *sqlite3_create_filename( 3707 const char *zDatabase, 3708 const char *zJournal, 3709 const char *zWal, 3710 int nParam, 3711 const char **azParam 3712); 3713void sqlite3_free_filename(char*); 3714 3715/* 3716** CAPI3REF: Error Codes And Messages 3717** METHOD: sqlite3 3718** 3719** ^If the most recent sqlite3_* API call associated with 3720** [database connection] D failed, then the sqlite3_errcode(D) interface 3721** returns the numeric [result code] or [extended result code] for that 3722** API call. 3723** ^The sqlite3_extended_errcode() 3724** interface is the same except that it always returns the 3725** [extended result code] even when extended result codes are 3726** disabled. 3727** 3728** The values returned by sqlite3_errcode() and/or 3729** sqlite3_extended_errcode() might change with each API call. 3730** Except, there are some interfaces that are guaranteed to never 3731** change the value of the error code. The error-code preserving 3732** interfaces are: 3733** 3734** <ul> 3735** <li> sqlite3_errcode() 3736** <li> sqlite3_extended_errcode() 3737** <li> sqlite3_errmsg() 3738** <li> sqlite3_errmsg16() 3739** </ul> 3740** 3741** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3742** text that describes the error, as either UTF-8 or UTF-16 respectively. 3743** ^(Memory to hold the error message string is managed internally. 3744** The application does not need to worry about freeing the result. 3745** However, the error string might be overwritten or deallocated by 3746** subsequent calls to other SQLite interface functions.)^ 3747** 3748** ^The sqlite3_errstr() interface returns the English-language text 3749** that describes the [result code], as UTF-8. 3750** ^(Memory to hold the error message string is managed internally 3751** and must not be freed by the application)^. 3752** 3753** When the serialized [threading mode] is in use, it might be the 3754** case that a second error occurs on a separate thread in between 3755** the time of the first error and the call to these interfaces. 3756** When that happens, the second error will be reported since these 3757** interfaces always report the most recent result. To avoid 3758** this, each thread can obtain exclusive use of the [database connection] D 3759** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3760** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3761** all calls to the interfaces listed here are completed. 3762** 3763** If an interface fails with SQLITE_MISUSE, that means the interface 3764** was invoked incorrectly by the application. In that case, the 3765** error code and message may or may not be set. 3766*/ 3767int sqlite3_errcode(sqlite3 *db); 3768int sqlite3_extended_errcode(sqlite3 *db); 3769const char *sqlite3_errmsg(sqlite3*); 3770const void *sqlite3_errmsg16(sqlite3*); 3771const char *sqlite3_errstr(int); 3772 3773/* 3774** CAPI3REF: Prepared Statement Object 3775** KEYWORDS: {prepared statement} {prepared statements} 3776** 3777** An instance of this object represents a single SQL statement that 3778** has been compiled into binary form and is ready to be evaluated. 3779** 3780** Think of each SQL statement as a separate computer program. The 3781** original SQL text is source code. A prepared statement object 3782** is the compiled object code. All SQL must be converted into a 3783** prepared statement before it can be run. 3784** 3785** The life-cycle of a prepared statement object usually goes like this: 3786** 3787** <ol> 3788** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3789** <li> Bind values to [parameters] using the sqlite3_bind_*() 3790** interfaces. 3791** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3792** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3793** to step 2. Do this zero or more times. 3794** <li> Destroy the object using [sqlite3_finalize()]. 3795** </ol> 3796*/ 3797typedef struct sqlite3_stmt sqlite3_stmt; 3798 3799/* 3800** CAPI3REF: Run-time Limits 3801** METHOD: sqlite3 3802** 3803** ^(This interface allows the size of various constructs to be limited 3804** on a connection by connection basis. The first parameter is the 3805** [database connection] whose limit is to be set or queried. The 3806** second parameter is one of the [limit categories] that define a 3807** class of constructs to be size limited. The third parameter is the 3808** new limit for that construct.)^ 3809** 3810** ^If the new limit is a negative number, the limit is unchanged. 3811** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3812** [limits | hard upper bound] 3813** set at compile-time by a C preprocessor macro called 3814** [limits | SQLITE_MAX_<i>NAME</i>]. 3815** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3816** ^Attempts to increase a limit above its hard upper bound are 3817** silently truncated to the hard upper bound. 3818** 3819** ^Regardless of whether or not the limit was changed, the 3820** [sqlite3_limit()] interface returns the prior value of the limit. 3821** ^Hence, to find the current value of a limit without changing it, 3822** simply invoke this interface with the third parameter set to -1. 3823** 3824** Run-time limits are intended for use in applications that manage 3825** both their own internal database and also databases that are controlled 3826** by untrusted external sources. An example application might be a 3827** web browser that has its own databases for storing history and 3828** separate databases controlled by JavaScript applications downloaded 3829** off the Internet. The internal databases can be given the 3830** large, default limits. Databases managed by external sources can 3831** be given much smaller limits designed to prevent a denial of service 3832** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3833** interface to further control untrusted SQL. The size of the database 3834** created by an untrusted script can be contained using the 3835** [max_page_count] [PRAGMA]. 3836** 3837** New run-time limit categories may be added in future releases. 3838*/ 3839int sqlite3_limit(sqlite3*, int id, int newVal); 3840 3841/* 3842** CAPI3REF: Run-Time Limit Categories 3843** KEYWORDS: {limit category} {*limit categories} 3844** 3845** These constants define various performance limits 3846** that can be lowered at run-time using [sqlite3_limit()]. 3847** The synopsis of the meanings of the various limits is shown below. 3848** Additional information is available at [limits | Limits in SQLite]. 3849** 3850** <dl> 3851** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3852** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3853** 3854** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3855** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3856** 3857** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3858** <dd>The maximum number of columns in a table definition or in the 3859** result set of a [SELECT] or the maximum number of columns in an index 3860** or in an ORDER BY or GROUP BY clause.</dd>)^ 3861** 3862** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3863** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3864** 3865** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3866** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3867** 3868** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3869** <dd>The maximum number of instructions in a virtual machine program 3870** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3871** the equivalent tries to allocate space for more than this many opcodes 3872** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3873** 3874** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3875** <dd>The maximum number of arguments on a function.</dd>)^ 3876** 3877** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3878** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3879** 3880** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3881** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3882** <dd>The maximum length of the pattern argument to the [LIKE] or 3883** [GLOB] operators.</dd>)^ 3884** 3885** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3886** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3887** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3888** 3889** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3890** <dd>The maximum depth of recursion for triggers.</dd>)^ 3891** 3892** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3893** <dd>The maximum number of auxiliary worker threads that a single 3894** [prepared statement] may start.</dd>)^ 3895** </dl> 3896*/ 3897#define SQLITE_LIMIT_LENGTH 0 3898#define SQLITE_LIMIT_SQL_LENGTH 1 3899#define SQLITE_LIMIT_COLUMN 2 3900#define SQLITE_LIMIT_EXPR_DEPTH 3 3901#define SQLITE_LIMIT_COMPOUND_SELECT 4 3902#define SQLITE_LIMIT_VDBE_OP 5 3903#define SQLITE_LIMIT_FUNCTION_ARG 6 3904#define SQLITE_LIMIT_ATTACHED 7 3905#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3906#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3907#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3908#define SQLITE_LIMIT_WORKER_THREADS 11 3909 3910/* 3911** CAPI3REF: Prepare Flags 3912** 3913** These constants define various flags that can be passed into 3914** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3915** [sqlite3_prepare16_v3()] interfaces. 3916** 3917** New flags may be added in future releases of SQLite. 3918** 3919** <dl> 3920** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3921** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3922** that the prepared statement will be retained for a long time and 3923** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3924** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3925** be used just once or at most a few times and then destroyed using 3926** [sqlite3_finalize()] relatively soon. The current implementation acts 3927** on this hint by avoiding the use of [lookaside memory] so as not to 3928** deplete the limited store of lookaside memory. Future versions of 3929** SQLite may act on this hint differently. 3930** 3931** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt> 3932** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used 3933** to be required for any prepared statement that wanted to use the 3934** [sqlite3_normalized_sql()] interface. However, the 3935** [sqlite3_normalized_sql()] interface is now available to all 3936** prepared statements, regardless of whether or not they use this 3937** flag. 3938** 3939** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt> 3940** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler 3941** to return an error (error code SQLITE_ERROR) if the statement uses 3942** any virtual tables. 3943** </dl> 3944*/ 3945#define SQLITE_PREPARE_PERSISTENT 0x01 3946#define SQLITE_PREPARE_NORMALIZE 0x02 3947#define SQLITE_PREPARE_NO_VTAB 0x04 3948 3949/* 3950** CAPI3REF: Compiling An SQL Statement 3951** KEYWORDS: {SQL statement compiler} 3952** METHOD: sqlite3 3953** CONSTRUCTOR: sqlite3_stmt 3954** 3955** To execute an SQL statement, it must first be compiled into a byte-code 3956** program using one of these routines. Or, in other words, these routines 3957** are constructors for the [prepared statement] object. 3958** 3959** The preferred routine to use is [sqlite3_prepare_v2()]. The 3960** [sqlite3_prepare()] interface is legacy and should be avoided. 3961** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3962** for special purposes. 3963** 3964** The use of the UTF-8 interfaces is preferred, as SQLite currently 3965** does all parsing using UTF-8. The UTF-16 interfaces are provided 3966** as a convenience. The UTF-16 interfaces work by converting the 3967** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3968** 3969** The first argument, "db", is a [database connection] obtained from a 3970** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3971** [sqlite3_open16()]. The database connection must not have been closed. 3972** 3973** The second argument, "zSql", is the statement to be compiled, encoded 3974** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3975** and sqlite3_prepare_v3() 3976** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3977** and sqlite3_prepare16_v3() use UTF-16. 3978** 3979** ^If the nByte argument is negative, then zSql is read up to the 3980** first zero terminator. ^If nByte is positive, then it is the 3981** number of bytes read from zSql. ^If nByte is zero, then no prepared 3982** statement is generated. 3983** If the caller knows that the supplied string is nul-terminated, then 3984** there is a small performance advantage to passing an nByte parameter that 3985** is the number of bytes in the input string <i>including</i> 3986** the nul-terminator. 3987** 3988** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3989** past the end of the first SQL statement in zSql. These routines only 3990** compile the first statement in zSql, so *pzTail is left pointing to 3991** what remains uncompiled. 3992** 3993** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3994** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3995** to NULL. ^If the input text contains no SQL (if the input is an empty 3996** string or a comment) then *ppStmt is set to NULL. 3997** The calling procedure is responsible for deleting the compiled 3998** SQL statement using [sqlite3_finalize()] after it has finished with it. 3999** ppStmt may not be NULL. 4000** 4001** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 4002** otherwise an [error code] is returned. 4003** 4004** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 4005** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 4006** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 4007** are retained for backwards compatibility, but their use is discouraged. 4008** ^In the "vX" interfaces, the prepared statement 4009** that is returned (the [sqlite3_stmt] object) contains a copy of the 4010** original SQL text. This causes the [sqlite3_step()] interface to 4011** behave differently in three ways: 4012** 4013** <ol> 4014** <li> 4015** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 4016** always used to do, [sqlite3_step()] will automatically recompile the SQL 4017** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 4018** retries will occur before sqlite3_step() gives up and returns an error. 4019** </li> 4020** 4021** <li> 4022** ^When an error occurs, [sqlite3_step()] will return one of the detailed 4023** [error codes] or [extended error codes]. ^The legacy behavior was that 4024** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 4025** and the application would have to make a second call to [sqlite3_reset()] 4026** in order to find the underlying cause of the problem. With the "v2" prepare 4027** interfaces, the underlying reason for the error is returned immediately. 4028** </li> 4029** 4030** <li> 4031** ^If the specific value bound to a [parameter | host parameter] in the 4032** WHERE clause might influence the choice of query plan for a statement, 4033** then the statement will be automatically recompiled, as if there had been 4034** a schema change, on the first [sqlite3_step()] call following any change 4035** to the [sqlite3_bind_text | bindings] of that [parameter]. 4036** ^The specific value of a WHERE-clause [parameter] might influence the 4037** choice of query plan if the parameter is the left-hand side of a [LIKE] 4038** or [GLOB] operator or if the parameter is compared to an indexed column 4039** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled. 4040** </li> 4041** </ol> 4042** 4043** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 4044** the extra prepFlags parameter, which is a bit array consisting of zero or 4045** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 4046** sqlite3_prepare_v2() interface works exactly the same as 4047** sqlite3_prepare_v3() with a zero prepFlags parameter. 4048*/ 4049int sqlite3_prepare( 4050 sqlite3 *db, /* Database handle */ 4051 const char *zSql, /* SQL statement, UTF-8 encoded */ 4052 int nByte, /* Maximum length of zSql in bytes. */ 4053 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4054 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4055); 4056int sqlite3_prepare_v2( 4057 sqlite3 *db, /* Database handle */ 4058 const char *zSql, /* SQL statement, UTF-8 encoded */ 4059 int nByte, /* Maximum length of zSql in bytes. */ 4060 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4061 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4062); 4063int sqlite3_prepare_v3( 4064 sqlite3 *db, /* Database handle */ 4065 const char *zSql, /* SQL statement, UTF-8 encoded */ 4066 int nByte, /* Maximum length of zSql in bytes. */ 4067 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4068 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4069 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4070); 4071int sqlite3_prepare16( 4072 sqlite3 *db, /* Database handle */ 4073 const void *zSql, /* SQL statement, UTF-16 encoded */ 4074 int nByte, /* Maximum length of zSql in bytes. */ 4075 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4076 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4077); 4078int sqlite3_prepare16_v2( 4079 sqlite3 *db, /* Database handle */ 4080 const void *zSql, /* SQL statement, UTF-16 encoded */ 4081 int nByte, /* Maximum length of zSql in bytes. */ 4082 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4083 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4084); 4085int sqlite3_prepare16_v3( 4086 sqlite3 *db, /* Database handle */ 4087 const void *zSql, /* SQL statement, UTF-16 encoded */ 4088 int nByte, /* Maximum length of zSql in bytes. */ 4089 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4090 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4091 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4092); 4093 4094/* 4095** CAPI3REF: Retrieving Statement SQL 4096** METHOD: sqlite3_stmt 4097** 4098** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 4099** SQL text used to create [prepared statement] P if P was 4100** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 4101** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4102** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 4103** string containing the SQL text of prepared statement P with 4104** [bound parameters] expanded. 4105** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8 4106** string containing the normalized SQL text of prepared statement P. The 4107** semantics used to normalize a SQL statement are unspecified and subject 4108** to change. At a minimum, literal values will be replaced with suitable 4109** placeholders. 4110** 4111** ^(For example, if a prepared statement is created using the SQL 4112** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 4113** and parameter :xyz is unbound, then sqlite3_sql() will return 4114** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 4115** will return "SELECT 2345,NULL".)^ 4116** 4117** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 4118** is available to hold the result, or if the result would exceed the 4119** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 4120** 4121** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 4122** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 4123** option causes sqlite3_expanded_sql() to always return NULL. 4124** 4125** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P) 4126** are managed by SQLite and are automatically freed when the prepared 4127** statement is finalized. 4128** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 4129** is obtained from [sqlite3_malloc()] and must be free by the application 4130** by passing it to [sqlite3_free()]. 4131*/ 4132const char *sqlite3_sql(sqlite3_stmt *pStmt); 4133char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 4134const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt); 4135 4136/* 4137** CAPI3REF: Determine If An SQL Statement Writes The Database 4138** METHOD: sqlite3_stmt 4139** 4140** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 4141** and only if the [prepared statement] X makes no direct changes to 4142** the content of the database file. 4143** 4144** Note that [application-defined SQL functions] or 4145** [virtual tables] might change the database indirectly as a side effect. 4146** ^(For example, if an application defines a function "eval()" that 4147** calls [sqlite3_exec()], then the following SQL statement would 4148** change the database file through side-effects: 4149** 4150** <blockquote><pre> 4151** SELECT eval('DELETE FROM t1') FROM t2; 4152** </pre></blockquote> 4153** 4154** But because the [SELECT] statement does not change the database file 4155** directly, sqlite3_stmt_readonly() would still return true.)^ 4156** 4157** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 4158** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 4159** since the statements themselves do not actually modify the database but 4160** rather they control the timing of when other statements modify the 4161** database. ^The [ATTACH] and [DETACH] statements also cause 4162** sqlite3_stmt_readonly() to return true since, while those statements 4163** change the configuration of a database connection, they do not make 4164** changes to the content of the database files on disk. 4165** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 4166** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 4167** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 4168** sqlite3_stmt_readonly() returns false for those commands. 4169*/ 4170int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 4171 4172/* 4173** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement 4174** METHOD: sqlite3_stmt 4175** 4176** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the 4177** prepared statement S is an EXPLAIN statement, or 2 if the 4178** statement S is an EXPLAIN QUERY PLAN. 4179** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is 4180** an ordinary statement or a NULL pointer. 4181*/ 4182int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt); 4183 4184/* 4185** CAPI3REF: Determine If A Prepared Statement Has Been Reset 4186** METHOD: sqlite3_stmt 4187** 4188** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 4189** [prepared statement] S has been stepped at least once using 4190** [sqlite3_step(S)] but has neither run to completion (returned 4191** [SQLITE_DONE] from [sqlite3_step(S)]) nor 4192** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 4193** interface returns false if S is a NULL pointer. If S is not a 4194** NULL pointer and is not a pointer to a valid [prepared statement] 4195** object, then the behavior is undefined and probably undesirable. 4196** 4197** This interface can be used in combination [sqlite3_next_stmt()] 4198** to locate all prepared statements associated with a database 4199** connection that are in need of being reset. This can be used, 4200** for example, in diagnostic routines to search for prepared 4201** statements that are holding a transaction open. 4202*/ 4203int sqlite3_stmt_busy(sqlite3_stmt*); 4204 4205/* 4206** CAPI3REF: Dynamically Typed Value Object 4207** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 4208** 4209** SQLite uses the sqlite3_value object to represent all values 4210** that can be stored in a database table. SQLite uses dynamic typing 4211** for the values it stores. ^Values stored in sqlite3_value objects 4212** can be integers, floating point values, strings, BLOBs, or NULL. 4213** 4214** An sqlite3_value object may be either "protected" or "unprotected". 4215** Some interfaces require a protected sqlite3_value. Other interfaces 4216** will accept either a protected or an unprotected sqlite3_value. 4217** Every interface that accepts sqlite3_value arguments specifies 4218** whether or not it requires a protected sqlite3_value. The 4219** [sqlite3_value_dup()] interface can be used to construct a new 4220** protected sqlite3_value from an unprotected sqlite3_value. 4221** 4222** The terms "protected" and "unprotected" refer to whether or not 4223** a mutex is held. An internal mutex is held for a protected 4224** sqlite3_value object but no mutex is held for an unprotected 4225** sqlite3_value object. If SQLite is compiled to be single-threaded 4226** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 4227** or if SQLite is run in one of reduced mutex modes 4228** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 4229** then there is no distinction between protected and unprotected 4230** sqlite3_value objects and they can be used interchangeably. However, 4231** for maximum code portability it is recommended that applications 4232** still make the distinction between protected and unprotected 4233** sqlite3_value objects even when not strictly required. 4234** 4235** ^The sqlite3_value objects that are passed as parameters into the 4236** implementation of [application-defined SQL functions] are protected. 4237** ^The sqlite3_value object returned by 4238** [sqlite3_column_value()] is unprotected. 4239** Unprotected sqlite3_value objects may only be used as arguments 4240** to [sqlite3_result_value()], [sqlite3_bind_value()], and 4241** [sqlite3_value_dup()]. 4242** The [sqlite3_value_blob | sqlite3_value_type()] family of 4243** interfaces require protected sqlite3_value objects. 4244*/ 4245typedef struct sqlite3_value sqlite3_value; 4246 4247/* 4248** CAPI3REF: SQL Function Context Object 4249** 4250** The context in which an SQL function executes is stored in an 4251** sqlite3_context object. ^A pointer to an sqlite3_context object 4252** is always first parameter to [application-defined SQL functions]. 4253** The application-defined SQL function implementation will pass this 4254** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 4255** [sqlite3_aggregate_context()], [sqlite3_user_data()], 4256** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 4257** and/or [sqlite3_set_auxdata()]. 4258*/ 4259typedef struct sqlite3_context sqlite3_context; 4260 4261/* 4262** CAPI3REF: Binding Values To Prepared Statements 4263** KEYWORDS: {host parameter} {host parameters} {host parameter name} 4264** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 4265** METHOD: sqlite3_stmt 4266** 4267** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 4268** literals may be replaced by a [parameter] that matches one of following 4269** templates: 4270** 4271** <ul> 4272** <li> ? 4273** <li> ?NNN 4274** <li> :VVV 4275** <li> @VVV 4276** <li> $VVV 4277** </ul> 4278** 4279** In the templates above, NNN represents an integer literal, 4280** and VVV represents an alphanumeric identifier.)^ ^The values of these 4281** parameters (also called "host parameter names" or "SQL parameters") 4282** can be set using the sqlite3_bind_*() routines defined here. 4283** 4284** ^The first argument to the sqlite3_bind_*() routines is always 4285** a pointer to the [sqlite3_stmt] object returned from 4286** [sqlite3_prepare_v2()] or its variants. 4287** 4288** ^The second argument is the index of the SQL parameter to be set. 4289** ^The leftmost SQL parameter has an index of 1. ^When the same named 4290** SQL parameter is used more than once, second and subsequent 4291** occurrences have the same index as the first occurrence. 4292** ^The index for named parameters can be looked up using the 4293** [sqlite3_bind_parameter_index()] API if desired. ^The index 4294** for "?NNN" parameters is the value of NNN. 4295** ^The NNN value must be between 1 and the [sqlite3_limit()] 4296** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766). 4297** 4298** ^The third argument is the value to bind to the parameter. 4299** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4300** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 4301** is ignored and the end result is the same as sqlite3_bind_null(). 4302** ^If the third parameter to sqlite3_bind_text() is not NULL, then 4303** it should be a pointer to well-formed UTF8 text. 4304** ^If the third parameter to sqlite3_bind_text16() is not NULL, then 4305** it should be a pointer to well-formed UTF16 text. 4306** ^If the third parameter to sqlite3_bind_text64() is not NULL, then 4307** it should be a pointer to a well-formed unicode string that is 4308** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16 4309** otherwise. 4310** 4311** [[byte-order determination rules]] ^The byte-order of 4312** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF) 4313** found in first character, which is removed, or in the absence of a BOM 4314** the byte order is the native byte order of the host 4315** machine for sqlite3_bind_text16() or the byte order specified in 4316** the 6th parameter for sqlite3_bind_text64().)^ 4317** ^If UTF16 input text contains invalid unicode 4318** characters, then SQLite might change those invalid characters 4319** into the unicode replacement character: U+FFFD. 4320** 4321** ^(In those routines that have a fourth argument, its value is the 4322** number of bytes in the parameter. To be clear: the value is the 4323** number of <u>bytes</u> in the value, not the number of characters.)^ 4324** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4325** is negative, then the length of the string is 4326** the number of bytes up to the first zero terminator. 4327** If the fourth parameter to sqlite3_bind_blob() is negative, then 4328** the behavior is undefined. 4329** If a non-negative fourth parameter is provided to sqlite3_bind_text() 4330** or sqlite3_bind_text16() or sqlite3_bind_text64() then 4331** that parameter must be the byte offset 4332** where the NUL terminator would occur assuming the string were NUL 4333** terminated. If any NUL characters occurs at byte offsets less than 4334** the value of the fourth parameter then the resulting string value will 4335** contain embedded NULs. The result of expressions involving strings 4336** with embedded NULs is undefined. 4337** 4338** ^The fifth argument to the BLOB and string binding interfaces 4339** is a destructor used to dispose of the BLOB or 4340** string after SQLite has finished with it. ^The destructor is called 4341** to dispose of the BLOB or string even if the call to the bind API fails, 4342** except the destructor is not called if the third parameter is a NULL 4343** pointer or the fourth parameter is negative. 4344** ^If the fifth argument is 4345** the special value [SQLITE_STATIC], then SQLite assumes that the 4346** information is in static, unmanaged space and does not need to be freed. 4347** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 4348** SQLite makes its own private copy of the data immediately, before 4349** the sqlite3_bind_*() routine returns. 4350** 4351** ^The sixth argument to sqlite3_bind_text64() must be one of 4352** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 4353** to specify the encoding of the text in the third parameter. If 4354** the sixth argument to sqlite3_bind_text64() is not one of the 4355** allowed values shown above, or if the text encoding is different 4356** from the encoding specified by the sixth parameter, then the behavior 4357** is undefined. 4358** 4359** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 4360** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 4361** (just an integer to hold its size) while it is being processed. 4362** Zeroblobs are intended to serve as placeholders for BLOBs whose 4363** content is later written using 4364** [sqlite3_blob_open | incremental BLOB I/O] routines. 4365** ^A negative value for the zeroblob results in a zero-length BLOB. 4366** 4367** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 4368** [prepared statement] S to have an SQL value of NULL, but to also be 4369** associated with the pointer P of type T. ^D is either a NULL pointer or 4370** a pointer to a destructor function for P. ^SQLite will invoke the 4371** destructor D with a single argument of P when it is finished using 4372** P. The T parameter should be a static string, preferably a string 4373** literal. The sqlite3_bind_pointer() routine is part of the 4374** [pointer passing interface] added for SQLite 3.20.0. 4375** 4376** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 4377** for the [prepared statement] or with a prepared statement for which 4378** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 4379** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 4380** routine is passed a [prepared statement] that has been finalized, the 4381** result is undefined and probably harmful. 4382** 4383** ^Bindings are not cleared by the [sqlite3_reset()] routine. 4384** ^Unbound parameters are interpreted as NULL. 4385** 4386** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 4387** [error code] if anything goes wrong. 4388** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 4389** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 4390** [SQLITE_MAX_LENGTH]. 4391** ^[SQLITE_RANGE] is returned if the parameter 4392** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 4393** 4394** See also: [sqlite3_bind_parameter_count()], 4395** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 4396*/ 4397int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 4398int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 4399 void(*)(void*)); 4400int sqlite3_bind_double(sqlite3_stmt*, int, double); 4401int sqlite3_bind_int(sqlite3_stmt*, int, int); 4402int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 4403int sqlite3_bind_null(sqlite3_stmt*, int); 4404int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 4405int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 4406int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 4407 void(*)(void*), unsigned char encoding); 4408int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 4409int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 4410int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 4411int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 4412 4413/* 4414** CAPI3REF: Number Of SQL Parameters 4415** METHOD: sqlite3_stmt 4416** 4417** ^This routine can be used to find the number of [SQL parameters] 4418** in a [prepared statement]. SQL parameters are tokens of the 4419** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4420** placeholders for values that are [sqlite3_bind_blob | bound] 4421** to the parameters at a later time. 4422** 4423** ^(This routine actually returns the index of the largest (rightmost) 4424** parameter. For all forms except ?NNN, this will correspond to the 4425** number of unique parameters. If parameters of the ?NNN form are used, 4426** there may be gaps in the list.)^ 4427** 4428** See also: [sqlite3_bind_blob|sqlite3_bind()], 4429** [sqlite3_bind_parameter_name()], and 4430** [sqlite3_bind_parameter_index()]. 4431*/ 4432int sqlite3_bind_parameter_count(sqlite3_stmt*); 4433 4434/* 4435** CAPI3REF: Name Of A Host Parameter 4436** METHOD: sqlite3_stmt 4437** 4438** ^The sqlite3_bind_parameter_name(P,N) interface returns 4439** the name of the N-th [SQL parameter] in the [prepared statement] P. 4440** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4441** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4442** respectively. 4443** In other words, the initial ":" or "$" or "@" or "?" 4444** is included as part of the name.)^ 4445** ^Parameters of the form "?" without a following integer have no name 4446** and are referred to as "nameless" or "anonymous parameters". 4447** 4448** ^The first host parameter has an index of 1, not 0. 4449** 4450** ^If the value N is out of range or if the N-th parameter is 4451** nameless, then NULL is returned. ^The returned string is 4452** always in UTF-8 encoding even if the named parameter was 4453** originally specified as UTF-16 in [sqlite3_prepare16()], 4454** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4455** 4456** See also: [sqlite3_bind_blob|sqlite3_bind()], 4457** [sqlite3_bind_parameter_count()], and 4458** [sqlite3_bind_parameter_index()]. 4459*/ 4460const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4461 4462/* 4463** CAPI3REF: Index Of A Parameter With A Given Name 4464** METHOD: sqlite3_stmt 4465** 4466** ^Return the index of an SQL parameter given its name. ^The 4467** index value returned is suitable for use as the second 4468** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4469** is returned if no matching parameter is found. ^The parameter 4470** name must be given in UTF-8 even if the original statement 4471** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4472** [sqlite3_prepare16_v3()]. 4473** 4474** See also: [sqlite3_bind_blob|sqlite3_bind()], 4475** [sqlite3_bind_parameter_count()], and 4476** [sqlite3_bind_parameter_name()]. 4477*/ 4478int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4479 4480/* 4481** CAPI3REF: Reset All Bindings On A Prepared Statement 4482** METHOD: sqlite3_stmt 4483** 4484** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4485** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4486** ^Use this routine to reset all host parameters to NULL. 4487*/ 4488int sqlite3_clear_bindings(sqlite3_stmt*); 4489 4490/* 4491** CAPI3REF: Number Of Columns In A Result Set 4492** METHOD: sqlite3_stmt 4493** 4494** ^Return the number of columns in the result set returned by the 4495** [prepared statement]. ^If this routine returns 0, that means the 4496** [prepared statement] returns no data (for example an [UPDATE]). 4497** ^However, just because this routine returns a positive number does not 4498** mean that one or more rows of data will be returned. ^A SELECT statement 4499** will always have a positive sqlite3_column_count() but depending on the 4500** WHERE clause constraints and the table content, it might return no rows. 4501** 4502** See also: [sqlite3_data_count()] 4503*/ 4504int sqlite3_column_count(sqlite3_stmt *pStmt); 4505 4506/* 4507** CAPI3REF: Column Names In A Result Set 4508** METHOD: sqlite3_stmt 4509** 4510** ^These routines return the name assigned to a particular column 4511** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4512** interface returns a pointer to a zero-terminated UTF-8 string 4513** and sqlite3_column_name16() returns a pointer to a zero-terminated 4514** UTF-16 string. ^The first parameter is the [prepared statement] 4515** that implements the [SELECT] statement. ^The second parameter is the 4516** column number. ^The leftmost column is number 0. 4517** 4518** ^The returned string pointer is valid until either the [prepared statement] 4519** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4520** reprepared by the first call to [sqlite3_step()] for a particular run 4521** or until the next call to 4522** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4523** 4524** ^If sqlite3_malloc() fails during the processing of either routine 4525** (for example during a conversion from UTF-8 to UTF-16) then a 4526** NULL pointer is returned. 4527** 4528** ^The name of a result column is the value of the "AS" clause for 4529** that column, if there is an AS clause. If there is no AS clause 4530** then the name of the column is unspecified and may change from 4531** one release of SQLite to the next. 4532*/ 4533const char *sqlite3_column_name(sqlite3_stmt*, int N); 4534const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4535 4536/* 4537** CAPI3REF: Source Of Data In A Query Result 4538** METHOD: sqlite3_stmt 4539** 4540** ^These routines provide a means to determine the database, table, and 4541** table column that is the origin of a particular result column in 4542** [SELECT] statement. 4543** ^The name of the database or table or column can be returned as 4544** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4545** the database name, the _table_ routines return the table name, and 4546** the origin_ routines return the column name. 4547** ^The returned string is valid until the [prepared statement] is destroyed 4548** using [sqlite3_finalize()] or until the statement is automatically 4549** reprepared by the first call to [sqlite3_step()] for a particular run 4550** or until the same information is requested 4551** again in a different encoding. 4552** 4553** ^The names returned are the original un-aliased names of the 4554** database, table, and column. 4555** 4556** ^The first argument to these interfaces is a [prepared statement]. 4557** ^These functions return information about the Nth result column returned by 4558** the statement, where N is the second function argument. 4559** ^The left-most column is column 0 for these routines. 4560** 4561** ^If the Nth column returned by the statement is an expression or 4562** subquery and is not a column value, then all of these functions return 4563** NULL. ^These routines might also return NULL if a memory allocation error 4564** occurs. ^Otherwise, they return the name of the attached database, table, 4565** or column that query result column was extracted from. 4566** 4567** ^As with all other SQLite APIs, those whose names end with "16" return 4568** UTF-16 encoded strings and the other functions return UTF-8. 4569** 4570** ^These APIs are only available if the library was compiled with the 4571** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4572** 4573** If two or more threads call one or more 4574** [sqlite3_column_database_name | column metadata interfaces] 4575** for the same [prepared statement] and result column 4576** at the same time then the results are undefined. 4577*/ 4578const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4579const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4580const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4581const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4582const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4583const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4584 4585/* 4586** CAPI3REF: Declared Datatype Of A Query Result 4587** METHOD: sqlite3_stmt 4588** 4589** ^(The first parameter is a [prepared statement]. 4590** If this statement is a [SELECT] statement and the Nth column of the 4591** returned result set of that [SELECT] is a table column (not an 4592** expression or subquery) then the declared type of the table 4593** column is returned.)^ ^If the Nth column of the result set is an 4594** expression or subquery, then a NULL pointer is returned. 4595** ^The returned string is always UTF-8 encoded. 4596** 4597** ^(For example, given the database schema: 4598** 4599** CREATE TABLE t1(c1 VARIANT); 4600** 4601** and the following statement to be compiled: 4602** 4603** SELECT c1 + 1, c1 FROM t1; 4604** 4605** this routine would return the string "VARIANT" for the second result 4606** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4607** 4608** ^SQLite uses dynamic run-time typing. ^So just because a column 4609** is declared to contain a particular type does not mean that the 4610** data stored in that column is of the declared type. SQLite is 4611** strongly typed, but the typing is dynamic not static. ^Type 4612** is associated with individual values, not with the containers 4613** used to hold those values. 4614*/ 4615const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4616const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4617 4618/* 4619** CAPI3REF: Evaluate An SQL Statement 4620** METHOD: sqlite3_stmt 4621** 4622** After a [prepared statement] has been prepared using any of 4623** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4624** or [sqlite3_prepare16_v3()] or one of the legacy 4625** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4626** must be called one or more times to evaluate the statement. 4627** 4628** The details of the behavior of the sqlite3_step() interface depend 4629** on whether the statement was prepared using the newer "vX" interfaces 4630** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4631** [sqlite3_prepare16_v2()] or the older legacy 4632** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4633** new "vX" interface is recommended for new applications but the legacy 4634** interface will continue to be supported. 4635** 4636** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4637** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4638** ^With the "v2" interface, any of the other [result codes] or 4639** [extended result codes] might be returned as well. 4640** 4641** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4642** database locks it needs to do its job. ^If the statement is a [COMMIT] 4643** or occurs outside of an explicit transaction, then you can retry the 4644** statement. If the statement is not a [COMMIT] and occurs within an 4645** explicit transaction then you should rollback the transaction before 4646** continuing. 4647** 4648** ^[SQLITE_DONE] means that the statement has finished executing 4649** successfully. sqlite3_step() should not be called again on this virtual 4650** machine without first calling [sqlite3_reset()] to reset the virtual 4651** machine back to its initial state. 4652** 4653** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4654** is returned each time a new row of data is ready for processing by the 4655** caller. The values may be accessed using the [column access functions]. 4656** sqlite3_step() is called again to retrieve the next row of data. 4657** 4658** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4659** violation) has occurred. sqlite3_step() should not be called again on 4660** the VM. More information may be found by calling [sqlite3_errmsg()]. 4661** ^With the legacy interface, a more specific error code (for example, 4662** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4663** can be obtained by calling [sqlite3_reset()] on the 4664** [prepared statement]. ^In the "v2" interface, 4665** the more specific error code is returned directly by sqlite3_step(). 4666** 4667** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4668** Perhaps it was called on a [prepared statement] that has 4669** already been [sqlite3_finalize | finalized] or on one that had 4670** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4671** be the case that the same database connection is being used by two or 4672** more threads at the same moment in time. 4673** 4674** For all versions of SQLite up to and including 3.6.23.1, a call to 4675** [sqlite3_reset()] was required after sqlite3_step() returned anything 4676** other than [SQLITE_ROW] before any subsequent invocation of 4677** sqlite3_step(). Failure to reset the prepared statement using 4678** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4679** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4680** sqlite3_step() began 4681** calling [sqlite3_reset()] automatically in this circumstance rather 4682** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4683** break because any application that ever receives an SQLITE_MISUSE error 4684** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4685** can be used to restore the legacy behavior. 4686** 4687** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4688** API always returns a generic error code, [SQLITE_ERROR], following any 4689** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4690** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4691** specific [error codes] that better describes the error. 4692** We admit that this is a goofy design. The problem has been fixed 4693** with the "v2" interface. If you prepare all of your SQL statements 4694** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4695** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4696** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4697** then the more specific [error codes] are returned directly 4698** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4699*/ 4700int sqlite3_step(sqlite3_stmt*); 4701 4702/* 4703** CAPI3REF: Number of columns in a result set 4704** METHOD: sqlite3_stmt 4705** 4706** ^The sqlite3_data_count(P) interface returns the number of columns in the 4707** current row of the result set of [prepared statement] P. 4708** ^If prepared statement P does not have results ready to return 4709** (via calls to the [sqlite3_column_int | sqlite3_column()] family of 4710** interfaces) then sqlite3_data_count(P) returns 0. 4711** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4712** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4713** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4714** will return non-zero if previous call to [sqlite3_step](P) returned 4715** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4716** where it always returns zero since each step of that multi-step 4717** pragma returns 0 columns of data. 4718** 4719** See also: [sqlite3_column_count()] 4720*/ 4721int sqlite3_data_count(sqlite3_stmt *pStmt); 4722 4723/* 4724** CAPI3REF: Fundamental Datatypes 4725** KEYWORDS: SQLITE_TEXT 4726** 4727** ^(Every value in SQLite has one of five fundamental datatypes: 4728** 4729** <ul> 4730** <li> 64-bit signed integer 4731** <li> 64-bit IEEE floating point number 4732** <li> string 4733** <li> BLOB 4734** <li> NULL 4735** </ul>)^ 4736** 4737** These constants are codes for each of those types. 4738** 4739** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4740** for a completely different meaning. Software that links against both 4741** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4742** SQLITE_TEXT. 4743*/ 4744#define SQLITE_INTEGER 1 4745#define SQLITE_FLOAT 2 4746#define SQLITE_BLOB 4 4747#define SQLITE_NULL 5 4748#ifdef SQLITE_TEXT 4749# undef SQLITE_TEXT 4750#else 4751# define SQLITE_TEXT 3 4752#endif 4753#define SQLITE3_TEXT 3 4754 4755/* 4756** CAPI3REF: Result Values From A Query 4757** KEYWORDS: {column access functions} 4758** METHOD: sqlite3_stmt 4759** 4760** <b>Summary:</b> 4761** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4762** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4763** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4764** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4765** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4766** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4767** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4768** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4769** [sqlite3_value|unprotected sqlite3_value] object. 4770** <tr><td> <td> <td> 4771** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4772** or a UTF-8 TEXT result in bytes 4773** <tr><td><b>sqlite3_column_bytes16 </b> 4774** <td>→ <td>Size of UTF-16 4775** TEXT in bytes 4776** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4777** datatype of the result 4778** </table></blockquote> 4779** 4780** <b>Details:</b> 4781** 4782** ^These routines return information about a single column of the current 4783** result row of a query. ^In every case the first argument is a pointer 4784** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4785** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4786** and the second argument is the index of the column for which information 4787** should be returned. ^The leftmost column of the result set has the index 0. 4788** ^The number of columns in the result can be determined using 4789** [sqlite3_column_count()]. 4790** 4791** If the SQL statement does not currently point to a valid row, or if the 4792** column index is out of range, the result is undefined. 4793** These routines may only be called when the most recent call to 4794** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4795** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4796** If any of these routines are called after [sqlite3_reset()] or 4797** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4798** something other than [SQLITE_ROW], the results are undefined. 4799** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4800** are called from a different thread while any of these routines 4801** are pending, then the results are undefined. 4802** 4803** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4804** each return the value of a result column in a specific data format. If 4805** the result column is not initially in the requested format (for example, 4806** if the query returns an integer but the sqlite3_column_text() interface 4807** is used to extract the value) then an automatic type conversion is performed. 4808** 4809** ^The sqlite3_column_type() routine returns the 4810** [SQLITE_INTEGER | datatype code] for the initial data type 4811** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4812** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4813** The return value of sqlite3_column_type() can be used to decide which 4814** of the first six interface should be used to extract the column value. 4815** The value returned by sqlite3_column_type() is only meaningful if no 4816** automatic type conversions have occurred for the value in question. 4817** After a type conversion, the result of calling sqlite3_column_type() 4818** is undefined, though harmless. Future 4819** versions of SQLite may change the behavior of sqlite3_column_type() 4820** following a type conversion. 4821** 4822** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4823** or sqlite3_column_bytes16() interfaces can be used to determine the size 4824** of that BLOB or string. 4825** 4826** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4827** routine returns the number of bytes in that BLOB or string. 4828** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4829** the string to UTF-8 and then returns the number of bytes. 4830** ^If the result is a numeric value then sqlite3_column_bytes() uses 4831** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4832** the number of bytes in that string. 4833** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4834** 4835** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4836** routine returns the number of bytes in that BLOB or string. 4837** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4838** the string to UTF-16 and then returns the number of bytes. 4839** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4840** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4841** the number of bytes in that string. 4842** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4843** 4844** ^The values returned by [sqlite3_column_bytes()] and 4845** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4846** of the string. ^For clarity: the values returned by 4847** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4848** bytes in the string, not the number of characters. 4849** 4850** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4851** even empty strings, are always zero-terminated. ^The return 4852** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4853** 4854** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4855** [unprotected sqlite3_value] object. In a multithreaded environment, 4856** an unprotected sqlite3_value object may only be used safely with 4857** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4858** If the [unprotected sqlite3_value] object returned by 4859** [sqlite3_column_value()] is used in any other way, including calls 4860** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4861** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4862** Hence, the sqlite3_column_value() interface 4863** is normally only useful within the implementation of 4864** [application-defined SQL functions] or [virtual tables], not within 4865** top-level application code. 4866** 4867** The these routines may attempt to convert the datatype of the result. 4868** ^For example, if the internal representation is FLOAT and a text result 4869** is requested, [sqlite3_snprintf()] is used internally to perform the 4870** conversion automatically. ^(The following table details the conversions 4871** that are applied: 4872** 4873** <blockquote> 4874** <table border="1"> 4875** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4876** 4877** <tr><td> NULL <td> INTEGER <td> Result is 0 4878** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4879** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4880** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4881** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4882** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4883** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4884** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4885** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4886** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4887** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4888** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4889** <tr><td> TEXT <td> BLOB <td> No change 4890** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4891** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4892** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4893** </table> 4894** </blockquote>)^ 4895** 4896** Note that when type conversions occur, pointers returned by prior 4897** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4898** sqlite3_column_text16() may be invalidated. 4899** Type conversions and pointer invalidations might occur 4900** in the following cases: 4901** 4902** <ul> 4903** <li> The initial content is a BLOB and sqlite3_column_text() or 4904** sqlite3_column_text16() is called. A zero-terminator might 4905** need to be added to the string.</li> 4906** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4907** sqlite3_column_text16() is called. The content must be converted 4908** to UTF-16.</li> 4909** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4910** sqlite3_column_text() is called. The content must be converted 4911** to UTF-8.</li> 4912** </ul> 4913** 4914** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4915** not invalidate a prior pointer, though of course the content of the buffer 4916** that the prior pointer references will have been modified. Other kinds 4917** of conversion are done in place when it is possible, but sometimes they 4918** are not possible and in those cases prior pointers are invalidated. 4919** 4920** The safest policy is to invoke these routines 4921** in one of the following ways: 4922** 4923** <ul> 4924** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4925** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4926** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4927** </ul> 4928** 4929** In other words, you should call sqlite3_column_text(), 4930** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4931** into the desired format, then invoke sqlite3_column_bytes() or 4932** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4933** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4934** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4935** with calls to sqlite3_column_bytes(). 4936** 4937** ^The pointers returned are valid until a type conversion occurs as 4938** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4939** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4940** and BLOBs is freed automatically. Do not pass the pointers returned 4941** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4942** [sqlite3_free()]. 4943** 4944** As long as the input parameters are correct, these routines will only 4945** fail if an out-of-memory error occurs during a format conversion. 4946** Only the following subset of interfaces are subject to out-of-memory 4947** errors: 4948** 4949** <ul> 4950** <li> sqlite3_column_blob() 4951** <li> sqlite3_column_text() 4952** <li> sqlite3_column_text16() 4953** <li> sqlite3_column_bytes() 4954** <li> sqlite3_column_bytes16() 4955** </ul> 4956** 4957** If an out-of-memory error occurs, then the return value from these 4958** routines is the same as if the column had contained an SQL NULL value. 4959** Valid SQL NULL returns can be distinguished from out-of-memory errors 4960** by invoking the [sqlite3_errcode()] immediately after the suspect 4961** return value is obtained and before any 4962** other SQLite interface is called on the same [database connection]. 4963*/ 4964const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4965double sqlite3_column_double(sqlite3_stmt*, int iCol); 4966int sqlite3_column_int(sqlite3_stmt*, int iCol); 4967sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4968const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4969const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4970sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4971int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4972int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4973int sqlite3_column_type(sqlite3_stmt*, int iCol); 4974 4975/* 4976** CAPI3REF: Destroy A Prepared Statement Object 4977** DESTRUCTOR: sqlite3_stmt 4978** 4979** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4980** ^If the most recent evaluation of the statement encountered no errors 4981** or if the statement is never been evaluated, then sqlite3_finalize() returns 4982** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4983** sqlite3_finalize(S) returns the appropriate [error code] or 4984** [extended error code]. 4985** 4986** ^The sqlite3_finalize(S) routine can be called at any point during 4987** the life cycle of [prepared statement] S: 4988** before statement S is ever evaluated, after 4989** one or more calls to [sqlite3_reset()], or after any call 4990** to [sqlite3_step()] regardless of whether or not the statement has 4991** completed execution. 4992** 4993** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4994** 4995** The application must finalize every [prepared statement] in order to avoid 4996** resource leaks. It is a grievous error for the application to try to use 4997** a prepared statement after it has been finalized. Any use of a prepared 4998** statement after it has been finalized can result in undefined and 4999** undesirable behavior such as segfaults and heap corruption. 5000*/ 5001int sqlite3_finalize(sqlite3_stmt *pStmt); 5002 5003/* 5004** CAPI3REF: Reset A Prepared Statement Object 5005** METHOD: sqlite3_stmt 5006** 5007** The sqlite3_reset() function is called to reset a [prepared statement] 5008** object back to its initial state, ready to be re-executed. 5009** ^Any SQL statement variables that had values bound to them using 5010** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 5011** Use [sqlite3_clear_bindings()] to reset the bindings. 5012** 5013** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 5014** back to the beginning of its program. 5015** 5016** ^If the most recent call to [sqlite3_step(S)] for the 5017** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 5018** or if [sqlite3_step(S)] has never before been called on S, 5019** then [sqlite3_reset(S)] returns [SQLITE_OK]. 5020** 5021** ^If the most recent call to [sqlite3_step(S)] for the 5022** [prepared statement] S indicated an error, then 5023** [sqlite3_reset(S)] returns an appropriate [error code]. 5024** 5025** ^The [sqlite3_reset(S)] interface does not change the values 5026** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 5027*/ 5028int sqlite3_reset(sqlite3_stmt *pStmt); 5029 5030/* 5031** CAPI3REF: Create Or Redefine SQL Functions 5032** KEYWORDS: {function creation routines} 5033** METHOD: sqlite3 5034** 5035** ^These functions (collectively known as "function creation routines") 5036** are used to add SQL functions or aggregates or to redefine the behavior 5037** of existing SQL functions or aggregates. The only differences between 5038** the three "sqlite3_create_function*" routines are the text encoding 5039** expected for the second parameter (the name of the function being 5040** created) and the presence or absence of a destructor callback for 5041** the application data pointer. Function sqlite3_create_window_function() 5042** is similar, but allows the user to supply the extra callback functions 5043** needed by [aggregate window functions]. 5044** 5045** ^The first parameter is the [database connection] to which the SQL 5046** function is to be added. ^If an application uses more than one database 5047** connection then application-defined SQL functions must be added 5048** to each database connection separately. 5049** 5050** ^The second parameter is the name of the SQL function to be created or 5051** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 5052** representation, exclusive of the zero-terminator. ^Note that the name 5053** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 5054** ^Any attempt to create a function with a longer name 5055** will result in [SQLITE_MISUSE] being returned. 5056** 5057** ^The third parameter (nArg) 5058** is the number of arguments that the SQL function or 5059** aggregate takes. ^If this parameter is -1, then the SQL function or 5060** aggregate may take any number of arguments between 0 and the limit 5061** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 5062** parameter is less than -1 or greater than 127 then the behavior is 5063** undefined. 5064** 5065** ^The fourth parameter, eTextRep, specifies what 5066** [SQLITE_UTF8 | text encoding] this SQL function prefers for 5067** its parameters. The application should set this parameter to 5068** [SQLITE_UTF16LE] if the function implementation invokes 5069** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 5070** implementation invokes [sqlite3_value_text16be()] on an input, or 5071** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 5072** otherwise. ^The same SQL function may be registered multiple times using 5073** different preferred text encodings, with different implementations for 5074** each encoding. 5075** ^When multiple implementations of the same function are available, SQLite 5076** will pick the one that involves the least amount of data conversion. 5077** 5078** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 5079** to signal that the function will always return the same result given 5080** the same inputs within a single SQL statement. Most SQL functions are 5081** deterministic. The built-in [random()] SQL function is an example of a 5082** function that is not deterministic. The SQLite query planner is able to 5083** perform additional optimizations on deterministic functions, so use 5084** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 5085** 5086** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY] 5087** flag, which if present prevents the function from being invoked from 5088** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions, 5089** index expressions, or the WHERE clause of partial indexes. 5090** 5091** <span style="background-color:#ffff90;"> 5092** For best security, the [SQLITE_DIRECTONLY] flag is recommended for 5093** all application-defined SQL functions that do not need to be 5094** used inside of triggers, view, CHECK constraints, or other elements of 5095** the database schema. This flags is especially recommended for SQL 5096** functions that have side effects or reveal internal application state. 5097** Without this flag, an attacker might be able to modify the schema of 5098** a database file to include invocations of the function with parameters 5099** chosen by the attacker, which the application will then execute when 5100** the database file is opened and read. 5101** </span> 5102** 5103** ^(The fifth parameter is an arbitrary pointer. The implementation of the 5104** function can gain access to this pointer using [sqlite3_user_data()].)^ 5105** 5106** ^The sixth, seventh and eighth parameters passed to the three 5107** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are 5108** pointers to C-language functions that implement the SQL function or 5109** aggregate. ^A scalar SQL function requires an implementation of the xFunc 5110** callback only; NULL pointers must be passed as the xStep and xFinal 5111** parameters. ^An aggregate SQL function requires an implementation of xStep 5112** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 5113** SQL function or aggregate, pass NULL pointers for all three function 5114** callbacks. 5115** 5116** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue 5117** and xInverse) passed to sqlite3_create_window_function are pointers to 5118** C-language callbacks that implement the new function. xStep and xFinal 5119** must both be non-NULL. xValue and xInverse may either both be NULL, in 5120** which case a regular aggregate function is created, or must both be 5121** non-NULL, in which case the new function may be used as either an aggregate 5122** or aggregate window function. More details regarding the implementation 5123** of aggregate window functions are 5124** [user-defined window functions|available here]. 5125** 5126** ^(If the final parameter to sqlite3_create_function_v2() or 5127** sqlite3_create_window_function() is not NULL, then it is destructor for 5128** the application data pointer. The destructor is invoked when the function 5129** is deleted, either by being overloaded or when the database connection 5130** closes.)^ ^The destructor is also invoked if the call to 5131** sqlite3_create_function_v2() fails. ^When the destructor callback is 5132** invoked, it is passed a single argument which is a copy of the application 5133** data pointer which was the fifth parameter to sqlite3_create_function_v2(). 5134** 5135** ^It is permitted to register multiple implementations of the same 5136** functions with the same name but with either differing numbers of 5137** arguments or differing preferred text encodings. ^SQLite will use 5138** the implementation that most closely matches the way in which the 5139** SQL function is used. ^A function implementation with a non-negative 5140** nArg parameter is a better match than a function implementation with 5141** a negative nArg. ^A function where the preferred text encoding 5142** matches the database encoding is a better 5143** match than a function where the encoding is different. 5144** ^A function where the encoding difference is between UTF16le and UTF16be 5145** is a closer match than a function where the encoding difference is 5146** between UTF8 and UTF16. 5147** 5148** ^Built-in functions may be overloaded by new application-defined functions. 5149** 5150** ^An application-defined function is permitted to call other 5151** SQLite interfaces. However, such calls must not 5152** close the database connection nor finalize or reset the prepared 5153** statement in which the function is running. 5154*/ 5155int sqlite3_create_function( 5156 sqlite3 *db, 5157 const char *zFunctionName, 5158 int nArg, 5159 int eTextRep, 5160 void *pApp, 5161 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5162 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5163 void (*xFinal)(sqlite3_context*) 5164); 5165int sqlite3_create_function16( 5166 sqlite3 *db, 5167 const void *zFunctionName, 5168 int nArg, 5169 int eTextRep, 5170 void *pApp, 5171 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5172 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5173 void (*xFinal)(sqlite3_context*) 5174); 5175int sqlite3_create_function_v2( 5176 sqlite3 *db, 5177 const char *zFunctionName, 5178 int nArg, 5179 int eTextRep, 5180 void *pApp, 5181 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5182 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5183 void (*xFinal)(sqlite3_context*), 5184 void(*xDestroy)(void*) 5185); 5186int sqlite3_create_window_function( 5187 sqlite3 *db, 5188 const char *zFunctionName, 5189 int nArg, 5190 int eTextRep, 5191 void *pApp, 5192 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5193 void (*xFinal)(sqlite3_context*), 5194 void (*xValue)(sqlite3_context*), 5195 void (*xInverse)(sqlite3_context*,int,sqlite3_value**), 5196 void(*xDestroy)(void*) 5197); 5198 5199/* 5200** CAPI3REF: Text Encodings 5201** 5202** These constant define integer codes that represent the various 5203** text encodings supported by SQLite. 5204*/ 5205#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 5206#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 5207#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 5208#define SQLITE_UTF16 4 /* Use native byte order */ 5209#define SQLITE_ANY 5 /* Deprecated */ 5210#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 5211 5212/* 5213** CAPI3REF: Function Flags 5214** 5215** These constants may be ORed together with the 5216** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 5217** to [sqlite3_create_function()], [sqlite3_create_function16()], or 5218** [sqlite3_create_function_v2()]. 5219** 5220** <dl> 5221** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd> 5222** The SQLITE_DETERMINISTIC flag means that the new function always gives 5223** the same output when the input parameters are the same. 5224** The [abs|abs() function] is deterministic, for example, but 5225** [randomblob|randomblob()] is not. Functions must 5226** be deterministic in order to be used in certain contexts such as 5227** with the WHERE clause of [partial indexes] or in [generated columns]. 5228** SQLite might also optimize deterministic functions by factoring them 5229** out of inner loops. 5230** </dd> 5231** 5232** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd> 5233** The SQLITE_DIRECTONLY flag means that the function may only be invoked 5234** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in 5235** schema structures such as [CHECK constraints], [DEFAULT clauses], 5236** [expression indexes], [partial indexes], or [generated columns]. 5237** The SQLITE_DIRECTONLY flags is a security feature which is recommended 5238** for all [application-defined SQL functions], and especially for functions 5239** that have side-effects or that could potentially leak sensitive 5240** information. 5241** </dd> 5242** 5243** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd> 5244** The SQLITE_INNOCUOUS flag means that the function is unlikely 5245** to cause problems even if misused. An innocuous function should have 5246** no side effects and should not depend on any values other than its 5247** input parameters. The [abs|abs() function] is an example of an 5248** innocuous function. 5249** The [load_extension() SQL function] is not innocuous because of its 5250** side effects. 5251** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not 5252** exactly the same. The [random|random() function] is an example of a 5253** function that is innocuous but not deterministic. 5254** <p>Some heightened security settings 5255** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF]) 5256** disable the use of SQL functions inside views and triggers and in 5257** schema structures such as [CHECK constraints], [DEFAULT clauses], 5258** [expression indexes], [partial indexes], and [generated columns] unless 5259** the function is tagged with SQLITE_INNOCUOUS. Most built-in functions 5260** are innocuous. Developers are advised to avoid using the 5261** SQLITE_INNOCUOUS flag for application-defined functions unless the 5262** function has been carefully audited and found to be free of potentially 5263** security-adverse side-effects and information-leaks. 5264** </dd> 5265** 5266** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd> 5267** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call 5268** [sqlite3_value_subtype()] to inspect the sub-types of its arguments. 5269** Specifying this flag makes no difference for scalar or aggregate user 5270** functions. However, if it is not specified for a user-defined window 5271** function, then any sub-types belonging to arguments passed to the window 5272** function may be discarded before the window function is called (i.e. 5273** sqlite3_value_subtype() will always return 0). 5274** </dd> 5275** </dl> 5276*/ 5277#define SQLITE_DETERMINISTIC 0x000000800 5278#define SQLITE_DIRECTONLY 0x000080000 5279#define SQLITE_SUBTYPE 0x000100000 5280#define SQLITE_INNOCUOUS 0x000200000 5281 5282/* 5283** CAPI3REF: Deprecated Functions 5284** DEPRECATED 5285** 5286** These functions are [deprecated]. In order to maintain 5287** backwards compatibility with older code, these functions continue 5288** to be supported. However, new applications should avoid 5289** the use of these functions. To encourage programmers to avoid 5290** these functions, we will not explain what they do. 5291*/ 5292#ifndef SQLITE_OMIT_DEPRECATED 5293SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 5294SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 5295SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 5296SQLITE_DEPRECATED int sqlite3_global_recover(void); 5297SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 5298SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 5299 void*,sqlite3_int64); 5300#endif 5301 5302/* 5303** CAPI3REF: Obtaining SQL Values 5304** METHOD: sqlite3_value 5305** 5306** <b>Summary:</b> 5307** <blockquote><table border=0 cellpadding=0 cellspacing=0> 5308** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 5309** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 5310** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 5311** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 5312** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 5313** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 5314** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 5315** the native byteorder 5316** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 5317** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 5318** <tr><td> <td> <td> 5319** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 5320** or a UTF-8 TEXT in bytes 5321** <tr><td><b>sqlite3_value_bytes16 </b> 5322** <td>→ <td>Size of UTF-16 5323** TEXT in bytes 5324** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 5325** datatype of the value 5326** <tr><td><b>sqlite3_value_numeric_type </b> 5327** <td>→ <td>Best numeric datatype of the value 5328** <tr><td><b>sqlite3_value_nochange </b> 5329** <td>→ <td>True if the column is unchanged in an UPDATE 5330** against a virtual table. 5331** <tr><td><b>sqlite3_value_frombind </b> 5332** <td>→ <td>True if value originated from a [bound parameter] 5333** </table></blockquote> 5334** 5335** <b>Details:</b> 5336** 5337** These routines extract type, size, and content information from 5338** [protected sqlite3_value] objects. Protected sqlite3_value objects 5339** are used to pass parameter information into the functions that 5340** implement [application-defined SQL functions] and [virtual tables]. 5341** 5342** These routines work only with [protected sqlite3_value] objects. 5343** Any attempt to use these routines on an [unprotected sqlite3_value] 5344** is not threadsafe. 5345** 5346** ^These routines work just like the corresponding [column access functions] 5347** except that these routines take a single [protected sqlite3_value] object 5348** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 5349** 5350** ^The sqlite3_value_text16() interface extracts a UTF-16 string 5351** in the native byte-order of the host machine. ^The 5352** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 5353** extract UTF-16 strings as big-endian and little-endian respectively. 5354** 5355** ^If [sqlite3_value] object V was initialized 5356** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 5357** and if X and Y are strings that compare equal according to strcmp(X,Y), 5358** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 5359** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 5360** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5361** 5362** ^(The sqlite3_value_type(V) interface returns the 5363** [SQLITE_INTEGER | datatype code] for the initial datatype of the 5364** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 5365** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 5366** Other interfaces might change the datatype for an sqlite3_value object. 5367** For example, if the datatype is initially SQLITE_INTEGER and 5368** sqlite3_value_text(V) is called to extract a text value for that 5369** integer, then subsequent calls to sqlite3_value_type(V) might return 5370** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 5371** occurs is undefined and may change from one release of SQLite to the next. 5372** 5373** ^(The sqlite3_value_numeric_type() interface attempts to apply 5374** numeric affinity to the value. This means that an attempt is 5375** made to convert the value to an integer or floating point. If 5376** such a conversion is possible without loss of information (in other 5377** words, if the value is a string that looks like a number) 5378** then the conversion is performed. Otherwise no conversion occurs. 5379** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 5380** 5381** ^Within the [xUpdate] method of a [virtual table], the 5382** sqlite3_value_nochange(X) interface returns true if and only if 5383** the column corresponding to X is unchanged by the UPDATE operation 5384** that the xUpdate method call was invoked to implement and if 5385** and the prior [xColumn] method call that was invoked to extracted 5386** the value for that column returned without setting a result (probably 5387** because it queried [sqlite3_vtab_nochange()] and found that the column 5388** was unchanging). ^Within an [xUpdate] method, any value for which 5389** sqlite3_value_nochange(X) is true will in all other respects appear 5390** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 5391** than within an [xUpdate] method call for an UPDATE statement, then 5392** the return value is arbitrary and meaningless. 5393** 5394** ^The sqlite3_value_frombind(X) interface returns non-zero if the 5395** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()] 5396** interfaces. ^If X comes from an SQL literal value, or a table column, 5397** or an expression, then sqlite3_value_frombind(X) returns zero. 5398** 5399** Please pay particular attention to the fact that the pointer returned 5400** from [sqlite3_value_blob()], [sqlite3_value_text()], or 5401** [sqlite3_value_text16()] can be invalidated by a subsequent call to 5402** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 5403** or [sqlite3_value_text16()]. 5404** 5405** These routines must be called from the same thread as 5406** the SQL function that supplied the [sqlite3_value*] parameters. 5407** 5408** As long as the input parameter is correct, these routines can only 5409** fail if an out-of-memory error occurs during a format conversion. 5410** Only the following subset of interfaces are subject to out-of-memory 5411** errors: 5412** 5413** <ul> 5414** <li> sqlite3_value_blob() 5415** <li> sqlite3_value_text() 5416** <li> sqlite3_value_text16() 5417** <li> sqlite3_value_text16le() 5418** <li> sqlite3_value_text16be() 5419** <li> sqlite3_value_bytes() 5420** <li> sqlite3_value_bytes16() 5421** </ul> 5422** 5423** If an out-of-memory error occurs, then the return value from these 5424** routines is the same as if the column had contained an SQL NULL value. 5425** Valid SQL NULL returns can be distinguished from out-of-memory errors 5426** by invoking the [sqlite3_errcode()] immediately after the suspect 5427** return value is obtained and before any 5428** other SQLite interface is called on the same [database connection]. 5429*/ 5430const void *sqlite3_value_blob(sqlite3_value*); 5431double sqlite3_value_double(sqlite3_value*); 5432int sqlite3_value_int(sqlite3_value*); 5433sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 5434void *sqlite3_value_pointer(sqlite3_value*, const char*); 5435const unsigned char *sqlite3_value_text(sqlite3_value*); 5436const void *sqlite3_value_text16(sqlite3_value*); 5437const void *sqlite3_value_text16le(sqlite3_value*); 5438const void *sqlite3_value_text16be(sqlite3_value*); 5439int sqlite3_value_bytes(sqlite3_value*); 5440int sqlite3_value_bytes16(sqlite3_value*); 5441int sqlite3_value_type(sqlite3_value*); 5442int sqlite3_value_numeric_type(sqlite3_value*); 5443int sqlite3_value_nochange(sqlite3_value*); 5444int sqlite3_value_frombind(sqlite3_value*); 5445 5446/* 5447** CAPI3REF: Finding The Subtype Of SQL Values 5448** METHOD: sqlite3_value 5449** 5450** The sqlite3_value_subtype(V) function returns the subtype for 5451** an [application-defined SQL function] argument V. The subtype 5452** information can be used to pass a limited amount of context from 5453** one SQL function to another. Use the [sqlite3_result_subtype()] 5454** routine to set the subtype for the return value of an SQL function. 5455*/ 5456unsigned int sqlite3_value_subtype(sqlite3_value*); 5457 5458/* 5459** CAPI3REF: Copy And Free SQL Values 5460** METHOD: sqlite3_value 5461** 5462** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 5463** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 5464** is a [protected sqlite3_value] object even if the input is not. 5465** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 5466** memory allocation fails. 5467** 5468** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 5469** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 5470** then sqlite3_value_free(V) is a harmless no-op. 5471*/ 5472sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 5473void sqlite3_value_free(sqlite3_value*); 5474 5475/* 5476** CAPI3REF: Obtain Aggregate Function Context 5477** METHOD: sqlite3_context 5478** 5479** Implementations of aggregate SQL functions use this 5480** routine to allocate memory for storing their state. 5481** 5482** ^The first time the sqlite3_aggregate_context(C,N) routine is called 5483** for a particular aggregate function, SQLite allocates 5484** N bytes of memory, zeroes out that memory, and returns a pointer 5485** to the new memory. ^On second and subsequent calls to 5486** sqlite3_aggregate_context() for the same aggregate function instance, 5487** the same buffer is returned. Sqlite3_aggregate_context() is normally 5488** called once for each invocation of the xStep callback and then one 5489** last time when the xFinal callback is invoked. ^(When no rows match 5490** an aggregate query, the xStep() callback of the aggregate function 5491** implementation is never called and xFinal() is called exactly once. 5492** In those cases, sqlite3_aggregate_context() might be called for the 5493** first time from within xFinal().)^ 5494** 5495** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 5496** when first called if N is less than or equal to zero or if a memory 5497** allocate error occurs. 5498** 5499** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 5500** determined by the N parameter on first successful call. Changing the 5501** value of N in any subsequent call to sqlite3_aggregate_context() within 5502** the same aggregate function instance will not resize the memory 5503** allocation.)^ Within the xFinal callback, it is customary to set 5504** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 5505** pointless memory allocations occur. 5506** 5507** ^SQLite automatically frees the memory allocated by 5508** sqlite3_aggregate_context() when the aggregate query concludes. 5509** 5510** The first parameter must be a copy of the 5511** [sqlite3_context | SQL function context] that is the first parameter 5512** to the xStep or xFinal callback routine that implements the aggregate 5513** function. 5514** 5515** This routine must be called from the same thread in which 5516** the aggregate SQL function is running. 5517*/ 5518void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 5519 5520/* 5521** CAPI3REF: User Data For Functions 5522** METHOD: sqlite3_context 5523** 5524** ^The sqlite3_user_data() interface returns a copy of 5525** the pointer that was the pUserData parameter (the 5th parameter) 5526** of the [sqlite3_create_function()] 5527** and [sqlite3_create_function16()] routines that originally 5528** registered the application defined function. 5529** 5530** This routine must be called from the same thread in which 5531** the application-defined function is running. 5532*/ 5533void *sqlite3_user_data(sqlite3_context*); 5534 5535/* 5536** CAPI3REF: Database Connection For Functions 5537** METHOD: sqlite3_context 5538** 5539** ^The sqlite3_context_db_handle() interface returns a copy of 5540** the pointer to the [database connection] (the 1st parameter) 5541** of the [sqlite3_create_function()] 5542** and [sqlite3_create_function16()] routines that originally 5543** registered the application defined function. 5544*/ 5545sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 5546 5547/* 5548** CAPI3REF: Function Auxiliary Data 5549** METHOD: sqlite3_context 5550** 5551** These functions may be used by (non-aggregate) SQL functions to 5552** associate metadata with argument values. If the same value is passed to 5553** multiple invocations of the same SQL function during query execution, under 5554** some circumstances the associated metadata may be preserved. An example 5555** of where this might be useful is in a regular-expression matching 5556** function. The compiled version of the regular expression can be stored as 5557** metadata associated with the pattern string. 5558** Then as long as the pattern string remains the same, 5559** the compiled regular expression can be reused on multiple 5560** invocations of the same function. 5561** 5562** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 5563** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 5564** value to the application-defined function. ^N is zero for the left-most 5565** function argument. ^If there is no metadata 5566** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 5567** returns a NULL pointer. 5568** 5569** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 5570** argument of the application-defined function. ^Subsequent 5571** calls to sqlite3_get_auxdata(C,N) return P from the most recent 5572** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5573** NULL if the metadata has been discarded. 5574** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5575** SQLite will invoke the destructor function X with parameter P exactly 5576** once, when the metadata is discarded. 5577** SQLite is free to discard the metadata at any time, including: <ul> 5578** <li> ^(when the corresponding function parameter changes)^, or 5579** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5580** SQL statement)^, or 5581** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5582** parameter)^, or 5583** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5584** allocation error occurs.)^ </ul> 5585** 5586** Note the last bullet in particular. The destructor X in 5587** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5588** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5589** should be called near the end of the function implementation and the 5590** function implementation should not make any use of P after 5591** sqlite3_set_auxdata() has been called. 5592** 5593** ^(In practice, metadata is preserved between function calls for 5594** function parameters that are compile-time constants, including literal 5595** values and [parameters] and expressions composed from the same.)^ 5596** 5597** The value of the N parameter to these interfaces should be non-negative. 5598** Future enhancements may make use of negative N values to define new 5599** kinds of function caching behavior. 5600** 5601** These routines must be called from the same thread in which 5602** the SQL function is running. 5603*/ 5604void *sqlite3_get_auxdata(sqlite3_context*, int N); 5605void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5606 5607 5608/* 5609** CAPI3REF: Constants Defining Special Destructor Behavior 5610** 5611** These are special values for the destructor that is passed in as the 5612** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5613** argument is SQLITE_STATIC, it means that the content pointer is constant 5614** and will never change. It does not need to be destroyed. ^The 5615** SQLITE_TRANSIENT value means that the content will likely change in 5616** the near future and that SQLite should make its own private copy of 5617** the content before returning. 5618** 5619** The typedef is necessary to work around problems in certain 5620** C++ compilers. 5621*/ 5622typedef void (*sqlite3_destructor_type)(void*); 5623#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5624#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5625 5626/* 5627** CAPI3REF: Setting The Result Of An SQL Function 5628** METHOD: sqlite3_context 5629** 5630** These routines are used by the xFunc or xFinal callbacks that 5631** implement SQL functions and aggregates. See 5632** [sqlite3_create_function()] and [sqlite3_create_function16()] 5633** for additional information. 5634** 5635** These functions work very much like the [parameter binding] family of 5636** functions used to bind values to host parameters in prepared statements. 5637** Refer to the [SQL parameter] documentation for additional information. 5638** 5639** ^The sqlite3_result_blob() interface sets the result from 5640** an application-defined function to be the BLOB whose content is pointed 5641** to by the second parameter and which is N bytes long where N is the 5642** third parameter. 5643** 5644** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5645** interfaces set the result of the application-defined function to be 5646** a BLOB containing all zero bytes and N bytes in size. 5647** 5648** ^The sqlite3_result_double() interface sets the result from 5649** an application-defined function to be a floating point value specified 5650** by its 2nd argument. 5651** 5652** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5653** cause the implemented SQL function to throw an exception. 5654** ^SQLite uses the string pointed to by the 5655** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5656** as the text of an error message. ^SQLite interprets the error 5657** message string from sqlite3_result_error() as UTF-8. ^SQLite 5658** interprets the string from sqlite3_result_error16() as UTF-16 using 5659** the same [byte-order determination rules] as [sqlite3_bind_text16()]. 5660** ^If the third parameter to sqlite3_result_error() 5661** or sqlite3_result_error16() is negative then SQLite takes as the error 5662** message all text up through the first zero character. 5663** ^If the third parameter to sqlite3_result_error() or 5664** sqlite3_result_error16() is non-negative then SQLite takes that many 5665** bytes (not characters) from the 2nd parameter as the error message. 5666** ^The sqlite3_result_error() and sqlite3_result_error16() 5667** routines make a private copy of the error message text before 5668** they return. Hence, the calling function can deallocate or 5669** modify the text after they return without harm. 5670** ^The sqlite3_result_error_code() function changes the error code 5671** returned by SQLite as a result of an error in a function. ^By default, 5672** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5673** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5674** 5675** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5676** error indicating that a string or BLOB is too long to represent. 5677** 5678** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5679** error indicating that a memory allocation failed. 5680** 5681** ^The sqlite3_result_int() interface sets the return value 5682** of the application-defined function to be the 32-bit signed integer 5683** value given in the 2nd argument. 5684** ^The sqlite3_result_int64() interface sets the return value 5685** of the application-defined function to be the 64-bit signed integer 5686** value given in the 2nd argument. 5687** 5688** ^The sqlite3_result_null() interface sets the return value 5689** of the application-defined function to be NULL. 5690** 5691** ^The sqlite3_result_text(), sqlite3_result_text16(), 5692** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5693** set the return value of the application-defined function to be 5694** a text string which is represented as UTF-8, UTF-16 native byte order, 5695** UTF-16 little endian, or UTF-16 big endian, respectively. 5696** ^The sqlite3_result_text64() interface sets the return value of an 5697** application-defined function to be a text string in an encoding 5698** specified by the fifth (and last) parameter, which must be one 5699** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5700** ^SQLite takes the text result from the application from 5701** the 2nd parameter of the sqlite3_result_text* interfaces. 5702** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5703** is negative, then SQLite takes result text from the 2nd parameter 5704** through the first zero character. 5705** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5706** is non-negative, then as many bytes (not characters) of the text 5707** pointed to by the 2nd parameter are taken as the application-defined 5708** function result. If the 3rd parameter is non-negative, then it 5709** must be the byte offset into the string where the NUL terminator would 5710** appear if the string where NUL terminated. If any NUL characters occur 5711** in the string at a byte offset that is less than the value of the 3rd 5712** parameter, then the resulting string will contain embedded NULs and the 5713** result of expressions operating on strings with embedded NULs is undefined. 5714** ^If the 4th parameter to the sqlite3_result_text* interfaces 5715** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5716** function as the destructor on the text or BLOB result when it has 5717** finished using that result. 5718** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5719** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5720** assumes that the text or BLOB result is in constant space and does not 5721** copy the content of the parameter nor call a destructor on the content 5722** when it has finished using that result. 5723** ^If the 4th parameter to the sqlite3_result_text* interfaces 5724** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5725** then SQLite makes a copy of the result into space obtained 5726** from [sqlite3_malloc()] before it returns. 5727** 5728** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and 5729** sqlite3_result_text16be() routines, and for sqlite3_result_text64() 5730** when the encoding is not UTF8, if the input UTF16 begins with a 5731** byte-order mark (BOM, U+FEFF) then the BOM is removed from the 5732** string and the rest of the string is interpreted according to the 5733** byte-order specified by the BOM. ^The byte-order specified by 5734** the BOM at the beginning of the text overrides the byte-order 5735** specified by the interface procedure. ^So, for example, if 5736** sqlite3_result_text16le() is invoked with text that begins 5737** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the 5738** first two bytes of input are skipped and the remaining input 5739** is interpreted as UTF16BE text. 5740** 5741** ^For UTF16 input text to the sqlite3_result_text16(), 5742** sqlite3_result_text16be(), sqlite3_result_text16le(), and 5743** sqlite3_result_text64() routines, if the text contains invalid 5744** UTF16 characters, the invalid characters might be converted 5745** into the unicode replacement character, U+FFFD. 5746** 5747** ^The sqlite3_result_value() interface sets the result of 5748** the application-defined function to be a copy of the 5749** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5750** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5751** so that the [sqlite3_value] specified in the parameter may change or 5752** be deallocated after sqlite3_result_value() returns without harm. 5753** ^A [protected sqlite3_value] object may always be used where an 5754** [unprotected sqlite3_value] object is required, so either 5755** kind of [sqlite3_value] object can be used with this interface. 5756** 5757** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5758** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5759** also associates the host-language pointer P or type T with that 5760** NULL value such that the pointer can be retrieved within an 5761** [application-defined SQL function] using [sqlite3_value_pointer()]. 5762** ^If the D parameter is not NULL, then it is a pointer to a destructor 5763** for the P parameter. ^SQLite invokes D with P as its only argument 5764** when SQLite is finished with P. The T parameter should be a static 5765** string and preferably a string literal. The sqlite3_result_pointer() 5766** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5767** 5768** If these routines are called from within the different thread 5769** than the one containing the application-defined function that received 5770** the [sqlite3_context] pointer, the results are undefined. 5771*/ 5772void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5773void sqlite3_result_blob64(sqlite3_context*,const void*, 5774 sqlite3_uint64,void(*)(void*)); 5775void sqlite3_result_double(sqlite3_context*, double); 5776void sqlite3_result_error(sqlite3_context*, const char*, int); 5777void sqlite3_result_error16(sqlite3_context*, const void*, int); 5778void sqlite3_result_error_toobig(sqlite3_context*); 5779void sqlite3_result_error_nomem(sqlite3_context*); 5780void sqlite3_result_error_code(sqlite3_context*, int); 5781void sqlite3_result_int(sqlite3_context*, int); 5782void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5783void sqlite3_result_null(sqlite3_context*); 5784void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5785void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5786 void(*)(void*), unsigned char encoding); 5787void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5788void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5789void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5790void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5791void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5792void sqlite3_result_zeroblob(sqlite3_context*, int n); 5793int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5794 5795 5796/* 5797** CAPI3REF: Setting The Subtype Of An SQL Function 5798** METHOD: sqlite3_context 5799** 5800** The sqlite3_result_subtype(C,T) function causes the subtype of 5801** the result from the [application-defined SQL function] with 5802** [sqlite3_context] C to be the value T. Only the lower 8 bits 5803** of the subtype T are preserved in current versions of SQLite; 5804** higher order bits are discarded. 5805** The number of subtype bytes preserved by SQLite might increase 5806** in future releases of SQLite. 5807*/ 5808void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5809 5810/* 5811** CAPI3REF: Define New Collating Sequences 5812** METHOD: sqlite3 5813** 5814** ^These functions add, remove, or modify a [collation] associated 5815** with the [database connection] specified as the first argument. 5816** 5817** ^The name of the collation is a UTF-8 string 5818** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5819** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5820** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5821** considered to be the same name. 5822** 5823** ^(The third argument (eTextRep) must be one of the constants: 5824** <ul> 5825** <li> [SQLITE_UTF8], 5826** <li> [SQLITE_UTF16LE], 5827** <li> [SQLITE_UTF16BE], 5828** <li> [SQLITE_UTF16], or 5829** <li> [SQLITE_UTF16_ALIGNED]. 5830** </ul>)^ 5831** ^The eTextRep argument determines the encoding of strings passed 5832** to the collating function callback, xCompare. 5833** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5834** force strings to be UTF16 with native byte order. 5835** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5836** on an even byte address. 5837** 5838** ^The fourth argument, pArg, is an application data pointer that is passed 5839** through as the first argument to the collating function callback. 5840** 5841** ^The fifth argument, xCompare, is a pointer to the collating function. 5842** ^Multiple collating functions can be registered using the same name but 5843** with different eTextRep parameters and SQLite will use whichever 5844** function requires the least amount of data transformation. 5845** ^If the xCompare argument is NULL then the collating function is 5846** deleted. ^When all collating functions having the same name are deleted, 5847** that collation is no longer usable. 5848** 5849** ^The collating function callback is invoked with a copy of the pArg 5850** application data pointer and with two strings in the encoding specified 5851** by the eTextRep argument. The two integer parameters to the collating 5852** function callback are the length of the two strings, in bytes. The collating 5853** function must return an integer that is negative, zero, or positive 5854** if the first string is less than, equal to, or greater than the second, 5855** respectively. A collating function must always return the same answer 5856** given the same inputs. If two or more collating functions are registered 5857** to the same collation name (using different eTextRep values) then all 5858** must give an equivalent answer when invoked with equivalent strings. 5859** The collating function must obey the following properties for all 5860** strings A, B, and C: 5861** 5862** <ol> 5863** <li> If A==B then B==A. 5864** <li> If A==B and B==C then A==C. 5865** <li> If A<B THEN B>A. 5866** <li> If A<B and B<C then A<C. 5867** </ol> 5868** 5869** If a collating function fails any of the above constraints and that 5870** collating function is registered and used, then the behavior of SQLite 5871** is undefined. 5872** 5873** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5874** with the addition that the xDestroy callback is invoked on pArg when 5875** the collating function is deleted. 5876** ^Collating functions are deleted when they are overridden by later 5877** calls to the collation creation functions or when the 5878** [database connection] is closed using [sqlite3_close()]. 5879** 5880** ^The xDestroy callback is <u>not</u> called if the 5881** sqlite3_create_collation_v2() function fails. Applications that invoke 5882** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5883** check the return code and dispose of the application data pointer 5884** themselves rather than expecting SQLite to deal with it for them. 5885** This is different from every other SQLite interface. The inconsistency 5886** is unfortunate but cannot be changed without breaking backwards 5887** compatibility. 5888** 5889** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5890*/ 5891int sqlite3_create_collation( 5892 sqlite3*, 5893 const char *zName, 5894 int eTextRep, 5895 void *pArg, 5896 int(*xCompare)(void*,int,const void*,int,const void*) 5897); 5898int sqlite3_create_collation_v2( 5899 sqlite3*, 5900 const char *zName, 5901 int eTextRep, 5902 void *pArg, 5903 int(*xCompare)(void*,int,const void*,int,const void*), 5904 void(*xDestroy)(void*) 5905); 5906int sqlite3_create_collation16( 5907 sqlite3*, 5908 const void *zName, 5909 int eTextRep, 5910 void *pArg, 5911 int(*xCompare)(void*,int,const void*,int,const void*) 5912); 5913 5914/* 5915** CAPI3REF: Collation Needed Callbacks 5916** METHOD: sqlite3 5917** 5918** ^To avoid having to register all collation sequences before a database 5919** can be used, a single callback function may be registered with the 5920** [database connection] to be invoked whenever an undefined collation 5921** sequence is required. 5922** 5923** ^If the function is registered using the sqlite3_collation_needed() API, 5924** then it is passed the names of undefined collation sequences as strings 5925** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5926** the names are passed as UTF-16 in machine native byte order. 5927** ^A call to either function replaces the existing collation-needed callback. 5928** 5929** ^(When the callback is invoked, the first argument passed is a copy 5930** of the second argument to sqlite3_collation_needed() or 5931** sqlite3_collation_needed16(). The second argument is the database 5932** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5933** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5934** sequence function required. The fourth parameter is the name of the 5935** required collation sequence.)^ 5936** 5937** The callback function should register the desired collation using 5938** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5939** [sqlite3_create_collation_v2()]. 5940*/ 5941int sqlite3_collation_needed( 5942 sqlite3*, 5943 void*, 5944 void(*)(void*,sqlite3*,int eTextRep,const char*) 5945); 5946int sqlite3_collation_needed16( 5947 sqlite3*, 5948 void*, 5949 void(*)(void*,sqlite3*,int eTextRep,const void*) 5950); 5951 5952#ifdef SQLITE_ENABLE_CEROD 5953/* 5954** Specify the activation key for a CEROD database. Unless 5955** activated, none of the CEROD routines will work. 5956*/ 5957void sqlite3_activate_cerod( 5958 const char *zPassPhrase /* Activation phrase */ 5959); 5960#endif 5961 5962/* 5963** CAPI3REF: Suspend Execution For A Short Time 5964** 5965** The sqlite3_sleep() function causes the current thread to suspend execution 5966** for at least a number of milliseconds specified in its parameter. 5967** 5968** If the operating system does not support sleep requests with 5969** millisecond time resolution, then the time will be rounded up to 5970** the nearest second. The number of milliseconds of sleep actually 5971** requested from the operating system is returned. 5972** 5973** ^SQLite implements this interface by calling the xSleep() 5974** method of the default [sqlite3_vfs] object. If the xSleep() method 5975** of the default VFS is not implemented correctly, or not implemented at 5976** all, then the behavior of sqlite3_sleep() may deviate from the description 5977** in the previous paragraphs. 5978*/ 5979int sqlite3_sleep(int); 5980 5981/* 5982** CAPI3REF: Name Of The Folder Holding Temporary Files 5983** 5984** ^(If this global variable is made to point to a string which is 5985** the name of a folder (a.k.a. directory), then all temporary files 5986** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5987** will be placed in that directory.)^ ^If this variable 5988** is a NULL pointer, then SQLite performs a search for an appropriate 5989** temporary file directory. 5990** 5991** Applications are strongly discouraged from using this global variable. 5992** It is required to set a temporary folder on Windows Runtime (WinRT). 5993** But for all other platforms, it is highly recommended that applications 5994** neither read nor write this variable. This global variable is a relic 5995** that exists for backwards compatibility of legacy applications and should 5996** be avoided in new projects. 5997** 5998** It is not safe to read or modify this variable in more than one 5999** thread at a time. It is not safe to read or modify this variable 6000** if a [database connection] is being used at the same time in a separate 6001** thread. 6002** It is intended that this variable be set once 6003** as part of process initialization and before any SQLite interface 6004** routines have been called and that this variable remain unchanged 6005** thereafter. 6006** 6007** ^The [temp_store_directory pragma] may modify this variable and cause 6008** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6009** the [temp_store_directory pragma] always assumes that any string 6010** that this variable points to is held in memory obtained from 6011** [sqlite3_malloc] and the pragma may attempt to free that memory 6012** using [sqlite3_free]. 6013** Hence, if this variable is modified directly, either it should be 6014** made NULL or made to point to memory obtained from [sqlite3_malloc] 6015** or else the use of the [temp_store_directory pragma] should be avoided. 6016** Except when requested by the [temp_store_directory pragma], SQLite 6017** does not free the memory that sqlite3_temp_directory points to. If 6018** the application wants that memory to be freed, it must do 6019** so itself, taking care to only do so after all [database connection] 6020** objects have been destroyed. 6021** 6022** <b>Note to Windows Runtime users:</b> The temporary directory must be set 6023** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 6024** features that require the use of temporary files may fail. Here is an 6025** example of how to do this using C++ with the Windows Runtime: 6026** 6027** <blockquote><pre> 6028** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 6029** TemporaryFolder->Path->Data(); 6030** char zPathBuf[MAX_PATH + 1]; 6031** memset(zPathBuf, 0, sizeof(zPathBuf)); 6032** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 6033** NULL, NULL); 6034** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 6035** </pre></blockquote> 6036*/ 6037SQLITE_EXTERN char *sqlite3_temp_directory; 6038 6039/* 6040** CAPI3REF: Name Of The Folder Holding Database Files 6041** 6042** ^(If this global variable is made to point to a string which is 6043** the name of a folder (a.k.a. directory), then all database files 6044** specified with a relative pathname and created or accessed by 6045** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 6046** to be relative to that directory.)^ ^If this variable is a NULL 6047** pointer, then SQLite assumes that all database files specified 6048** with a relative pathname are relative to the current directory 6049** for the process. Only the windows VFS makes use of this global 6050** variable; it is ignored by the unix VFS. 6051** 6052** Changing the value of this variable while a database connection is 6053** open can result in a corrupt database. 6054** 6055** It is not safe to read or modify this variable in more than one 6056** thread at a time. It is not safe to read or modify this variable 6057** if a [database connection] is being used at the same time in a separate 6058** thread. 6059** It is intended that this variable be set once 6060** as part of process initialization and before any SQLite interface 6061** routines have been called and that this variable remain unchanged 6062** thereafter. 6063** 6064** ^The [data_store_directory pragma] may modify this variable and cause 6065** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6066** the [data_store_directory pragma] always assumes that any string 6067** that this variable points to is held in memory obtained from 6068** [sqlite3_malloc] and the pragma may attempt to free that memory 6069** using [sqlite3_free]. 6070** Hence, if this variable is modified directly, either it should be 6071** made NULL or made to point to memory obtained from [sqlite3_malloc] 6072** or else the use of the [data_store_directory pragma] should be avoided. 6073*/ 6074SQLITE_EXTERN char *sqlite3_data_directory; 6075 6076/* 6077** CAPI3REF: Win32 Specific Interface 6078** 6079** These interfaces are available only on Windows. The 6080** [sqlite3_win32_set_directory] interface is used to set the value associated 6081** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to 6082** zValue, depending on the value of the type parameter. The zValue parameter 6083** should be NULL to cause the previous value to be freed via [sqlite3_free]; 6084** a non-NULL value will be copied into memory obtained from [sqlite3_malloc] 6085** prior to being used. The [sqlite3_win32_set_directory] interface returns 6086** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported, 6087** or [SQLITE_NOMEM] if memory could not be allocated. The value of the 6088** [sqlite3_data_directory] variable is intended to act as a replacement for 6089** the current directory on the sub-platforms of Win32 where that concept is 6090** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and 6091** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the 6092** sqlite3_win32_set_directory interface except the string parameter must be 6093** UTF-8 or UTF-16, respectively. 6094*/ 6095int sqlite3_win32_set_directory( 6096 unsigned long type, /* Identifier for directory being set or reset */ 6097 void *zValue /* New value for directory being set or reset */ 6098); 6099int sqlite3_win32_set_directory8(unsigned long type, const char *zValue); 6100int sqlite3_win32_set_directory16(unsigned long type, const void *zValue); 6101 6102/* 6103** CAPI3REF: Win32 Directory Types 6104** 6105** These macros are only available on Windows. They define the allowed values 6106** for the type argument to the [sqlite3_win32_set_directory] interface. 6107*/ 6108#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1 6109#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2 6110 6111/* 6112** CAPI3REF: Test For Auto-Commit Mode 6113** KEYWORDS: {autocommit mode} 6114** METHOD: sqlite3 6115** 6116** ^The sqlite3_get_autocommit() interface returns non-zero or 6117** zero if the given database connection is or is not in autocommit mode, 6118** respectively. ^Autocommit mode is on by default. 6119** ^Autocommit mode is disabled by a [BEGIN] statement. 6120** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 6121** 6122** If certain kinds of errors occur on a statement within a multi-statement 6123** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 6124** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 6125** transaction might be rolled back automatically. The only way to 6126** find out whether SQLite automatically rolled back the transaction after 6127** an error is to use this function. 6128** 6129** If another thread changes the autocommit status of the database 6130** connection while this routine is running, then the return value 6131** is undefined. 6132*/ 6133int sqlite3_get_autocommit(sqlite3*); 6134 6135/* 6136** CAPI3REF: Find The Database Handle Of A Prepared Statement 6137** METHOD: sqlite3_stmt 6138** 6139** ^The sqlite3_db_handle interface returns the [database connection] handle 6140** to which a [prepared statement] belongs. ^The [database connection] 6141** returned by sqlite3_db_handle is the same [database connection] 6142** that was the first argument 6143** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 6144** create the statement in the first place. 6145*/ 6146sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 6147 6148/* 6149** CAPI3REF: Return The Filename For A Database Connection 6150** METHOD: sqlite3 6151** 6152** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename 6153** associated with database N of connection D. 6154** ^If there is no attached database N on the database 6155** connection D, or if database N is a temporary or in-memory database, then 6156** this function will return either a NULL pointer or an empty string. 6157** 6158** ^The string value returned by this routine is owned and managed by 6159** the database connection. ^The value will be valid until the database N 6160** is [DETACH]-ed or until the database connection closes. 6161** 6162** ^The filename returned by this function is the output of the 6163** xFullPathname method of the [VFS]. ^In other words, the filename 6164** will be an absolute pathname, even if the filename used 6165** to open the database originally was a URI or relative pathname. 6166** 6167** If the filename pointer returned by this routine is not NULL, then it 6168** can be used as the filename input parameter to these routines: 6169** <ul> 6170** <li> [sqlite3_uri_parameter()] 6171** <li> [sqlite3_uri_boolean()] 6172** <li> [sqlite3_uri_int64()] 6173** <li> [sqlite3_filename_database()] 6174** <li> [sqlite3_filename_journal()] 6175** <li> [sqlite3_filename_wal()] 6176** </ul> 6177*/ 6178const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 6179 6180/* 6181** CAPI3REF: Determine if a database is read-only 6182** METHOD: sqlite3 6183** 6184** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 6185** of connection D is read-only, 0 if it is read/write, or -1 if N is not 6186** the name of a database on connection D. 6187*/ 6188int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 6189 6190/* 6191** CAPI3REF: Determine the transaction state of a database 6192** METHOD: sqlite3 6193** 6194** ^The sqlite3_txn_state(D,S) interface returns the current 6195** [transaction state] of schema S in database connection D. ^If S is NULL, 6196** then the highest transaction state of any schema on databse connection D 6197** is returned. Transaction states are (in order of lowest to highest): 6198** <ol> 6199** <li value="0"> SQLITE_TXN_NONE 6200** <li value="1"> SQLITE_TXN_READ 6201** <li value="2"> SQLITE_TXN_WRITE 6202** </ol> 6203** ^If the S argument to sqlite3_txn_state(D,S) is not the name of 6204** a valid schema, then -1 is returned. 6205*/ 6206int sqlite3_txn_state(sqlite3*,const char *zSchema); 6207 6208/* 6209** CAPI3REF: Allowed return values from [sqlite3_txn_state()] 6210** KEYWORDS: {transaction state} 6211** 6212** These constants define the current transaction state of a database file. 6213** ^The [sqlite3_txn_state(D,S)] interface returns one of these 6214** constants in order to describe the transaction state of schema S 6215** in [database connection] D. 6216** 6217** <dl> 6218** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt> 6219** <dd>The SQLITE_TXN_NONE state means that no transaction is currently 6220** pending.</dd> 6221** 6222** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt> 6223** <dd>The SQLITE_TXN_READ state means that the database is currently 6224** in a read transaction. Content has been read from the database file 6225** but nothing in the database file has changed. The transaction state 6226** will advanced to SQLITE_TXN_WRITE if any changes occur and there are 6227** no other conflicting concurrent write transactions. The transaction 6228** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or 6229** [COMMIT].</dd> 6230** 6231** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt> 6232** <dd>The SQLITE_TXN_WRITE state means that the database is currently 6233** in a write transaction. Content has been written to the database file 6234** but has not yet committed. The transaction state will change to 6235** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd> 6236*/ 6237#define SQLITE_TXN_NONE 0 6238#define SQLITE_TXN_READ 1 6239#define SQLITE_TXN_WRITE 2 6240 6241/* 6242** CAPI3REF: Find the next prepared statement 6243** METHOD: sqlite3 6244** 6245** ^This interface returns a pointer to the next [prepared statement] after 6246** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 6247** then this interface returns a pointer to the first prepared statement 6248** associated with the database connection pDb. ^If no prepared statement 6249** satisfies the conditions of this routine, it returns NULL. 6250** 6251** The [database connection] pointer D in a call to 6252** [sqlite3_next_stmt(D,S)] must refer to an open database 6253** connection and in particular must not be a NULL pointer. 6254*/ 6255sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 6256 6257/* 6258** CAPI3REF: Commit And Rollback Notification Callbacks 6259** METHOD: sqlite3 6260** 6261** ^The sqlite3_commit_hook() interface registers a callback 6262** function to be invoked whenever a transaction is [COMMIT | committed]. 6263** ^Any callback set by a previous call to sqlite3_commit_hook() 6264** for the same database connection is overridden. 6265** ^The sqlite3_rollback_hook() interface registers a callback 6266** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 6267** ^Any callback set by a previous call to sqlite3_rollback_hook() 6268** for the same database connection is overridden. 6269** ^The pArg argument is passed through to the callback. 6270** ^If the callback on a commit hook function returns non-zero, 6271** then the commit is converted into a rollback. 6272** 6273** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 6274** return the P argument from the previous call of the same function 6275** on the same [database connection] D, or NULL for 6276** the first call for each function on D. 6277** 6278** The commit and rollback hook callbacks are not reentrant. 6279** The callback implementation must not do anything that will modify 6280** the database connection that invoked the callback. Any actions 6281** to modify the database connection must be deferred until after the 6282** completion of the [sqlite3_step()] call that triggered the commit 6283** or rollback hook in the first place. 6284** Note that running any other SQL statements, including SELECT statements, 6285** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 6286** the database connections for the meaning of "modify" in this paragraph. 6287** 6288** ^Registering a NULL function disables the callback. 6289** 6290** ^When the commit hook callback routine returns zero, the [COMMIT] 6291** operation is allowed to continue normally. ^If the commit hook 6292** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 6293** ^The rollback hook is invoked on a rollback that results from a commit 6294** hook returning non-zero, just as it would be with any other rollback. 6295** 6296** ^For the purposes of this API, a transaction is said to have been 6297** rolled back if an explicit "ROLLBACK" statement is executed, or 6298** an error or constraint causes an implicit rollback to occur. 6299** ^The rollback callback is not invoked if a transaction is 6300** automatically rolled back because the database connection is closed. 6301** 6302** See also the [sqlite3_update_hook()] interface. 6303*/ 6304void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 6305void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 6306 6307/* 6308** CAPI3REF: Data Change Notification Callbacks 6309** METHOD: sqlite3 6310** 6311** ^The sqlite3_update_hook() interface registers a callback function 6312** with the [database connection] identified by the first argument 6313** to be invoked whenever a row is updated, inserted or deleted in 6314** a [rowid table]. 6315** ^Any callback set by a previous call to this function 6316** for the same database connection is overridden. 6317** 6318** ^The second argument is a pointer to the function to invoke when a 6319** row is updated, inserted or deleted in a rowid table. 6320** ^The first argument to the callback is a copy of the third argument 6321** to sqlite3_update_hook(). 6322** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 6323** or [SQLITE_UPDATE], depending on the operation that caused the callback 6324** to be invoked. 6325** ^The third and fourth arguments to the callback contain pointers to the 6326** database and table name containing the affected row. 6327** ^The final callback parameter is the [rowid] of the row. 6328** ^In the case of an update, this is the [rowid] after the update takes place. 6329** 6330** ^(The update hook is not invoked when internal system tables are 6331** modified (i.e. sqlite_sequence).)^ 6332** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 6333** 6334** ^In the current implementation, the update hook 6335** is not invoked when conflicting rows are deleted because of an 6336** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 6337** invoked when rows are deleted using the [truncate optimization]. 6338** The exceptions defined in this paragraph might change in a future 6339** release of SQLite. 6340** 6341** The update hook implementation must not do anything that will modify 6342** the database connection that invoked the update hook. Any actions 6343** to modify the database connection must be deferred until after the 6344** completion of the [sqlite3_step()] call that triggered the update hook. 6345** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 6346** database connections for the meaning of "modify" in this paragraph. 6347** 6348** ^The sqlite3_update_hook(D,C,P) function 6349** returns the P argument from the previous call 6350** on the same [database connection] D, or NULL for 6351** the first call on D. 6352** 6353** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 6354** and [sqlite3_preupdate_hook()] interfaces. 6355*/ 6356void *sqlite3_update_hook( 6357 sqlite3*, 6358 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 6359 void* 6360); 6361 6362/* 6363** CAPI3REF: Enable Or Disable Shared Pager Cache 6364** 6365** ^(This routine enables or disables the sharing of the database cache 6366** and schema data structures between [database connection | connections] 6367** to the same database. Sharing is enabled if the argument is true 6368** and disabled if the argument is false.)^ 6369** 6370** ^Cache sharing is enabled and disabled for an entire process. 6371** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 6372** In prior versions of SQLite, 6373** sharing was enabled or disabled for each thread separately. 6374** 6375** ^(The cache sharing mode set by this interface effects all subsequent 6376** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 6377** Existing database connections continue to use the sharing mode 6378** that was in effect at the time they were opened.)^ 6379** 6380** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 6381** successfully. An [error code] is returned otherwise.)^ 6382** 6383** ^Shared cache is disabled by default. It is recommended that it stay 6384** that way. In other words, do not use this routine. This interface 6385** continues to be provided for historical compatibility, but its use is 6386** discouraged. Any use of shared cache is discouraged. If shared cache 6387** must be used, it is recommended that shared cache only be enabled for 6388** individual database connections using the [sqlite3_open_v2()] interface 6389** with the [SQLITE_OPEN_SHAREDCACHE] flag. 6390** 6391** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 6392** and will always return SQLITE_MISUSE. On those systems, 6393** shared cache mode should be enabled per-database connection via 6394** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 6395** 6396** This interface is threadsafe on processors where writing a 6397** 32-bit integer is atomic. 6398** 6399** See Also: [SQLite Shared-Cache Mode] 6400*/ 6401int sqlite3_enable_shared_cache(int); 6402 6403/* 6404** CAPI3REF: Attempt To Free Heap Memory 6405** 6406** ^The sqlite3_release_memory() interface attempts to free N bytes 6407** of heap memory by deallocating non-essential memory allocations 6408** held by the database library. Memory used to cache database 6409** pages to improve performance is an example of non-essential memory. 6410** ^sqlite3_release_memory() returns the number of bytes actually freed, 6411** which might be more or less than the amount requested. 6412** ^The sqlite3_release_memory() routine is a no-op returning zero 6413** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 6414** 6415** See also: [sqlite3_db_release_memory()] 6416*/ 6417int sqlite3_release_memory(int); 6418 6419/* 6420** CAPI3REF: Free Memory Used By A Database Connection 6421** METHOD: sqlite3 6422** 6423** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 6424** memory as possible from database connection D. Unlike the 6425** [sqlite3_release_memory()] interface, this interface is in effect even 6426** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 6427** omitted. 6428** 6429** See also: [sqlite3_release_memory()] 6430*/ 6431int sqlite3_db_release_memory(sqlite3*); 6432 6433/* 6434** CAPI3REF: Impose A Limit On Heap Size 6435** 6436** These interfaces impose limits on the amount of heap memory that will be 6437** by all database connections within a single process. 6438** 6439** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 6440** soft limit on the amount of heap memory that may be allocated by SQLite. 6441** ^SQLite strives to keep heap memory utilization below the soft heap 6442** limit by reducing the number of pages held in the page cache 6443** as heap memory usages approaches the limit. 6444** ^The soft heap limit is "soft" because even though SQLite strives to stay 6445** below the limit, it will exceed the limit rather than generate 6446** an [SQLITE_NOMEM] error. In other words, the soft heap limit 6447** is advisory only. 6448** 6449** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of 6450** N bytes on the amount of memory that will be allocated. ^The 6451** sqlite3_hard_heap_limit64(N) interface is similar to 6452** sqlite3_soft_heap_limit64(N) except that memory allocations will fail 6453** when the hard heap limit is reached. 6454** 6455** ^The return value from both sqlite3_soft_heap_limit64() and 6456** sqlite3_hard_heap_limit64() is the size of 6457** the heap limit prior to the call, or negative in the case of an 6458** error. ^If the argument N is negative 6459** then no change is made to the heap limit. Hence, the current 6460** size of heap limits can be determined by invoking 6461** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1). 6462** 6463** ^Setting the heap limits to zero disables the heap limiter mechanism. 6464** 6465** ^The soft heap limit may not be greater than the hard heap limit. 6466** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N) 6467** is invoked with a value of N that is greater than the hard heap limit, 6468** the the soft heap limit is set to the value of the hard heap limit. 6469** ^The soft heap limit is automatically enabled whenever the hard heap 6470** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and 6471** the soft heap limit is outside the range of 1..N, then the soft heap 6472** limit is set to N. ^Invoking sqlite3_soft_heap_limit64(0) when the 6473** hard heap limit is enabled makes the soft heap limit equal to the 6474** hard heap limit. 6475** 6476** The memory allocation limits can also be adjusted using 6477** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit]. 6478** 6479** ^(The heap limits are not enforced in the current implementation 6480** if one or more of following conditions are true: 6481** 6482** <ul> 6483** <li> The limit value is set to zero. 6484** <li> Memory accounting is disabled using a combination of the 6485** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 6486** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 6487** <li> An alternative page cache implementation is specified using 6488** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 6489** <li> The page cache allocates from its own memory pool supplied 6490** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 6491** from the heap. 6492** </ul>)^ 6493** 6494** The circumstances under which SQLite will enforce the heap limits may 6495** changes in future releases of SQLite. 6496*/ 6497sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 6498sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N); 6499 6500/* 6501** CAPI3REF: Deprecated Soft Heap Limit Interface 6502** DEPRECATED 6503** 6504** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 6505** interface. This routine is provided for historical compatibility 6506** only. All new applications should use the 6507** [sqlite3_soft_heap_limit64()] interface rather than this one. 6508*/ 6509SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 6510 6511 6512/* 6513** CAPI3REF: Extract Metadata About A Column Of A Table 6514** METHOD: sqlite3 6515** 6516** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 6517** information about column C of table T in database D 6518** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 6519** interface returns SQLITE_OK and fills in the non-NULL pointers in 6520** the final five arguments with appropriate values if the specified 6521** column exists. ^The sqlite3_table_column_metadata() interface returns 6522** SQLITE_ERROR if the specified column does not exist. 6523** ^If the column-name parameter to sqlite3_table_column_metadata() is a 6524** NULL pointer, then this routine simply checks for the existence of the 6525** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 6526** does not. If the table name parameter T in a call to 6527** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 6528** undefined behavior. 6529** 6530** ^The column is identified by the second, third and fourth parameters to 6531** this function. ^(The second parameter is either the name of the database 6532** (i.e. "main", "temp", or an attached database) containing the specified 6533** table or NULL.)^ ^If it is NULL, then all attached databases are searched 6534** for the table using the same algorithm used by the database engine to 6535** resolve unqualified table references. 6536** 6537** ^The third and fourth parameters to this function are the table and column 6538** name of the desired column, respectively. 6539** 6540** ^Metadata is returned by writing to the memory locations passed as the 5th 6541** and subsequent parameters to this function. ^Any of these arguments may be 6542** NULL, in which case the corresponding element of metadata is omitted. 6543** 6544** ^(<blockquote> 6545** <table border="1"> 6546** <tr><th> Parameter <th> Output<br>Type <th> Description 6547** 6548** <tr><td> 5th <td> const char* <td> Data type 6549** <tr><td> 6th <td> const char* <td> Name of default collation sequence 6550** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 6551** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 6552** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 6553** </table> 6554** </blockquote>)^ 6555** 6556** ^The memory pointed to by the character pointers returned for the 6557** declaration type and collation sequence is valid until the next 6558** call to any SQLite API function. 6559** 6560** ^If the specified table is actually a view, an [error code] is returned. 6561** 6562** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 6563** is not a [WITHOUT ROWID] table and an 6564** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 6565** parameters are set for the explicitly declared column. ^(If there is no 6566** [INTEGER PRIMARY KEY] column, then the outputs 6567** for the [rowid] are set as follows: 6568** 6569** <pre> 6570** data type: "INTEGER" 6571** collation sequence: "BINARY" 6572** not null: 0 6573** primary key: 1 6574** auto increment: 0 6575** </pre>)^ 6576** 6577** ^This function causes all database schemas to be read from disk and 6578** parsed, if that has not already been done, and returns an error if 6579** any errors are encountered while loading the schema. 6580*/ 6581int sqlite3_table_column_metadata( 6582 sqlite3 *db, /* Connection handle */ 6583 const char *zDbName, /* Database name or NULL */ 6584 const char *zTableName, /* Table name */ 6585 const char *zColumnName, /* Column name */ 6586 char const **pzDataType, /* OUTPUT: Declared data type */ 6587 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 6588 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 6589 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 6590 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 6591); 6592 6593/* 6594** CAPI3REF: Load An Extension 6595** METHOD: sqlite3 6596** 6597** ^This interface loads an SQLite extension library from the named file. 6598** 6599** ^The sqlite3_load_extension() interface attempts to load an 6600** [SQLite extension] library contained in the file zFile. If 6601** the file cannot be loaded directly, attempts are made to load 6602** with various operating-system specific extensions added. 6603** So for example, if "samplelib" cannot be loaded, then names like 6604** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 6605** be tried also. 6606** 6607** ^The entry point is zProc. 6608** ^(zProc may be 0, in which case SQLite will try to come up with an 6609** entry point name on its own. It first tries "sqlite3_extension_init". 6610** If that does not work, it constructs a name "sqlite3_X_init" where the 6611** X is consists of the lower-case equivalent of all ASCII alphabetic 6612** characters in the filename from the last "/" to the first following 6613** "." and omitting any initial "lib".)^ 6614** ^The sqlite3_load_extension() interface returns 6615** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 6616** ^If an error occurs and pzErrMsg is not 0, then the 6617** [sqlite3_load_extension()] interface shall attempt to 6618** fill *pzErrMsg with error message text stored in memory 6619** obtained from [sqlite3_malloc()]. The calling function 6620** should free this memory by calling [sqlite3_free()]. 6621** 6622** ^Extension loading must be enabled using 6623** [sqlite3_enable_load_extension()] or 6624** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 6625** prior to calling this API, 6626** otherwise an error will be returned. 6627** 6628** <b>Security warning:</b> It is recommended that the 6629** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 6630** interface. The use of the [sqlite3_enable_load_extension()] interface 6631** should be avoided. This will keep the SQL function [load_extension()] 6632** disabled and prevent SQL injections from giving attackers 6633** access to extension loading capabilities. 6634** 6635** See also the [load_extension() SQL function]. 6636*/ 6637int sqlite3_load_extension( 6638 sqlite3 *db, /* Load the extension into this database connection */ 6639 const char *zFile, /* Name of the shared library containing extension */ 6640 const char *zProc, /* Entry point. Derived from zFile if 0 */ 6641 char **pzErrMsg /* Put error message here if not 0 */ 6642); 6643 6644/* 6645** CAPI3REF: Enable Or Disable Extension Loading 6646** METHOD: sqlite3 6647** 6648** ^So as not to open security holes in older applications that are 6649** unprepared to deal with [extension loading], and as a means of disabling 6650** [extension loading] while evaluating user-entered SQL, the following API 6651** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 6652** 6653** ^Extension loading is off by default. 6654** ^Call the sqlite3_enable_load_extension() routine with onoff==1 6655** to turn extension loading on and call it with onoff==0 to turn 6656** it back off again. 6657** 6658** ^This interface enables or disables both the C-API 6659** [sqlite3_load_extension()] and the SQL function [load_extension()]. 6660** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 6661** to enable or disable only the C-API.)^ 6662** 6663** <b>Security warning:</b> It is recommended that extension loading 6664** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 6665** rather than this interface, so the [load_extension()] SQL function 6666** remains disabled. This will prevent SQL injections from giving attackers 6667** access to extension loading capabilities. 6668*/ 6669int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6670 6671/* 6672** CAPI3REF: Automatically Load Statically Linked Extensions 6673** 6674** ^This interface causes the xEntryPoint() function to be invoked for 6675** each new [database connection] that is created. The idea here is that 6676** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6677** that is to be automatically loaded into all new database connections. 6678** 6679** ^(Even though the function prototype shows that xEntryPoint() takes 6680** no arguments and returns void, SQLite invokes xEntryPoint() with three 6681** arguments and expects an integer result as if the signature of the 6682** entry point where as follows: 6683** 6684** <blockquote><pre> 6685** int xEntryPoint( 6686** sqlite3 *db, 6687** const char **pzErrMsg, 6688** const struct sqlite3_api_routines *pThunk 6689** ); 6690** </pre></blockquote>)^ 6691** 6692** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6693** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6694** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6695** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6696** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6697** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6698** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6699** 6700** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6701** on the list of automatic extensions is a harmless no-op. ^No entry point 6702** will be called more than once for each database connection that is opened. 6703** 6704** See also: [sqlite3_reset_auto_extension()] 6705** and [sqlite3_cancel_auto_extension()] 6706*/ 6707int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6708 6709/* 6710** CAPI3REF: Cancel Automatic Extension Loading 6711** 6712** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6713** initialization routine X that was registered using a prior call to 6714** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6715** routine returns 1 if initialization routine X was successfully 6716** unregistered and it returns 0 if X was not on the list of initialization 6717** routines. 6718*/ 6719int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6720 6721/* 6722** CAPI3REF: Reset Automatic Extension Loading 6723** 6724** ^This interface disables all automatic extensions previously 6725** registered using [sqlite3_auto_extension()]. 6726*/ 6727void sqlite3_reset_auto_extension(void); 6728 6729/* 6730** The interface to the virtual-table mechanism is currently considered 6731** to be experimental. The interface might change in incompatible ways. 6732** If this is a problem for you, do not use the interface at this time. 6733** 6734** When the virtual-table mechanism stabilizes, we will declare the 6735** interface fixed, support it indefinitely, and remove this comment. 6736*/ 6737 6738/* 6739** Structures used by the virtual table interface 6740*/ 6741typedef struct sqlite3_vtab sqlite3_vtab; 6742typedef struct sqlite3_index_info sqlite3_index_info; 6743typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6744typedef struct sqlite3_module sqlite3_module; 6745 6746/* 6747** CAPI3REF: Virtual Table Object 6748** KEYWORDS: sqlite3_module {virtual table module} 6749** 6750** This structure, sometimes called a "virtual table module", 6751** defines the implementation of a [virtual table]. 6752** This structure consists mostly of methods for the module. 6753** 6754** ^A virtual table module is created by filling in a persistent 6755** instance of this structure and passing a pointer to that instance 6756** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6757** ^The registration remains valid until it is replaced by a different 6758** module or until the [database connection] closes. The content 6759** of this structure must not change while it is registered with 6760** any database connection. 6761*/ 6762struct sqlite3_module { 6763 int iVersion; 6764 int (*xCreate)(sqlite3*, void *pAux, 6765 int argc, const char *const*argv, 6766 sqlite3_vtab **ppVTab, char**); 6767 int (*xConnect)(sqlite3*, void *pAux, 6768 int argc, const char *const*argv, 6769 sqlite3_vtab **ppVTab, char**); 6770 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6771 int (*xDisconnect)(sqlite3_vtab *pVTab); 6772 int (*xDestroy)(sqlite3_vtab *pVTab); 6773 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6774 int (*xClose)(sqlite3_vtab_cursor*); 6775 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6776 int argc, sqlite3_value **argv); 6777 int (*xNext)(sqlite3_vtab_cursor*); 6778 int (*xEof)(sqlite3_vtab_cursor*); 6779 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6780 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6781 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6782 int (*xBegin)(sqlite3_vtab *pVTab); 6783 int (*xSync)(sqlite3_vtab *pVTab); 6784 int (*xCommit)(sqlite3_vtab *pVTab); 6785 int (*xRollback)(sqlite3_vtab *pVTab); 6786 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6787 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6788 void **ppArg); 6789 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6790 /* The methods above are in version 1 of the sqlite_module object. Those 6791 ** below are for version 2 and greater. */ 6792 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6793 int (*xRelease)(sqlite3_vtab *pVTab, int); 6794 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6795 /* The methods above are in versions 1 and 2 of the sqlite_module object. 6796 ** Those below are for version 3 and greater. */ 6797 int (*xShadowName)(const char*); 6798}; 6799 6800/* 6801** CAPI3REF: Virtual Table Indexing Information 6802** KEYWORDS: sqlite3_index_info 6803** 6804** The sqlite3_index_info structure and its substructures is used as part 6805** of the [virtual table] interface to 6806** pass information into and receive the reply from the [xBestIndex] 6807** method of a [virtual table module]. The fields under **Inputs** are the 6808** inputs to xBestIndex and are read-only. xBestIndex inserts its 6809** results into the **Outputs** fields. 6810** 6811** ^(The aConstraint[] array records WHERE clause constraints of the form: 6812** 6813** <blockquote>column OP expr</blockquote> 6814** 6815** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6816** stored in aConstraint[].op using one of the 6817** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6818** ^(The index of the column is stored in 6819** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6820** expr on the right-hand side can be evaluated (and thus the constraint 6821** is usable) and false if it cannot.)^ 6822** 6823** ^The optimizer automatically inverts terms of the form "expr OP column" 6824** and makes other simplifications to the WHERE clause in an attempt to 6825** get as many WHERE clause terms into the form shown above as possible. 6826** ^The aConstraint[] array only reports WHERE clause terms that are 6827** relevant to the particular virtual table being queried. 6828** 6829** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6830** ^Each term of aOrderBy records a column of the ORDER BY clause. 6831** 6832** The colUsed field indicates which columns of the virtual table may be 6833** required by the current scan. Virtual table columns are numbered from 6834** zero in the order in which they appear within the CREATE TABLE statement 6835** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6836** the corresponding bit is set within the colUsed mask if the column may be 6837** required by SQLite. If the table has at least 64 columns and any column 6838** to the right of the first 63 is required, then bit 63 of colUsed is also 6839** set. In other words, column iCol may be required if the expression 6840** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6841** non-zero. 6842** 6843** The [xBestIndex] method must fill aConstraintUsage[] with information 6844** about what parameters to pass to xFilter. ^If argvIndex>0 then 6845** the right-hand side of the corresponding aConstraint[] is evaluated 6846** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6847** is true, then the constraint is assumed to be fully handled by the 6848** virtual table and might not be checked again by the byte code.)^ ^(The 6849** aConstraintUsage[].omit flag is an optimization hint. When the omit flag 6850** is left in its default setting of false, the constraint will always be 6851** checked separately in byte code. If the omit flag is change to true, then 6852** the constraint may or may not be checked in byte code. In other words, 6853** when the omit flag is true there is no guarantee that the constraint will 6854** not be checked again using byte code.)^ 6855** 6856** ^The idxNum and idxPtr values are recorded and passed into the 6857** [xFilter] method. 6858** ^[sqlite3_free()] is used to free idxPtr if and only if 6859** needToFreeIdxPtr is true. 6860** 6861** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6862** the correct order to satisfy the ORDER BY clause so that no separate 6863** sorting step is required. 6864** 6865** ^The estimatedCost value is an estimate of the cost of a particular 6866** strategy. A cost of N indicates that the cost of the strategy is similar 6867** to a linear scan of an SQLite table with N rows. A cost of log(N) 6868** indicates that the expense of the operation is similar to that of a 6869** binary search on a unique indexed field of an SQLite table with N rows. 6870** 6871** ^The estimatedRows value is an estimate of the number of rows that 6872** will be returned by the strategy. 6873** 6874** The xBestIndex method may optionally populate the idxFlags field with a 6875** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6876** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6877** assumes that the strategy may visit at most one row. 6878** 6879** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6880** SQLite also assumes that if a call to the xUpdate() method is made as 6881** part of the same statement to delete or update a virtual table row and the 6882** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6883** any database changes. In other words, if the xUpdate() returns 6884** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6885** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6886** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6887** the xUpdate method are automatically rolled back by SQLite. 6888** 6889** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6890** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6891** If a virtual table extension is 6892** used with an SQLite version earlier than 3.8.2, the results of attempting 6893** to read or write the estimatedRows field are undefined (but are likely 6894** to include crashing the application). The estimatedRows field should 6895** therefore only be used if [sqlite3_libversion_number()] returns a 6896** value greater than or equal to 3008002. Similarly, the idxFlags field 6897** was added for [version 3.9.0] ([dateof:3.9.0]). 6898** It may therefore only be used if 6899** sqlite3_libversion_number() returns a value greater than or equal to 6900** 3009000. 6901*/ 6902struct sqlite3_index_info { 6903 /* Inputs */ 6904 int nConstraint; /* Number of entries in aConstraint */ 6905 struct sqlite3_index_constraint { 6906 int iColumn; /* Column constrained. -1 for ROWID */ 6907 unsigned char op; /* Constraint operator */ 6908 unsigned char usable; /* True if this constraint is usable */ 6909 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6910 } *aConstraint; /* Table of WHERE clause constraints */ 6911 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6912 struct sqlite3_index_orderby { 6913 int iColumn; /* Column number */ 6914 unsigned char desc; /* True for DESC. False for ASC. */ 6915 } *aOrderBy; /* The ORDER BY clause */ 6916 /* Outputs */ 6917 struct sqlite3_index_constraint_usage { 6918 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6919 unsigned char omit; /* Do not code a test for this constraint */ 6920 } *aConstraintUsage; 6921 int idxNum; /* Number used to identify the index */ 6922 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6923 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6924 int orderByConsumed; /* True if output is already ordered */ 6925 double estimatedCost; /* Estimated cost of using this index */ 6926 /* Fields below are only available in SQLite 3.8.2 and later */ 6927 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6928 /* Fields below are only available in SQLite 3.9.0 and later */ 6929 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6930 /* Fields below are only available in SQLite 3.10.0 and later */ 6931 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6932}; 6933 6934/* 6935** CAPI3REF: Virtual Table Scan Flags 6936** 6937** Virtual table implementations are allowed to set the 6938** [sqlite3_index_info].idxFlags field to some combination of 6939** these bits. 6940*/ 6941#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6942 6943/* 6944** CAPI3REF: Virtual Table Constraint Operator Codes 6945** 6946** These macros define the allowed values for the 6947** [sqlite3_index_info].aConstraint[].op field. Each value represents 6948** an operator that is part of a constraint term in the wHERE clause of 6949** a query that uses a [virtual table]. 6950*/ 6951#define SQLITE_INDEX_CONSTRAINT_EQ 2 6952#define SQLITE_INDEX_CONSTRAINT_GT 4 6953#define SQLITE_INDEX_CONSTRAINT_LE 8 6954#define SQLITE_INDEX_CONSTRAINT_LT 16 6955#define SQLITE_INDEX_CONSTRAINT_GE 32 6956#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6957#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6958#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6959#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6960#define SQLITE_INDEX_CONSTRAINT_NE 68 6961#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6962#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6963#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6964#define SQLITE_INDEX_CONSTRAINT_IS 72 6965#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150 6966 6967/* 6968** CAPI3REF: Register A Virtual Table Implementation 6969** METHOD: sqlite3 6970** 6971** ^These routines are used to register a new [virtual table module] name. 6972** ^Module names must be registered before 6973** creating a new [virtual table] using the module and before using a 6974** preexisting [virtual table] for the module. 6975** 6976** ^The module name is registered on the [database connection] specified 6977** by the first parameter. ^The name of the module is given by the 6978** second parameter. ^The third parameter is a pointer to 6979** the implementation of the [virtual table module]. ^The fourth 6980** parameter is an arbitrary client data pointer that is passed through 6981** into the [xCreate] and [xConnect] methods of the virtual table module 6982** when a new virtual table is be being created or reinitialized. 6983** 6984** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6985** is a pointer to a destructor for the pClientData. ^SQLite will 6986** invoke the destructor function (if it is not NULL) when SQLite 6987** no longer needs the pClientData pointer. ^The destructor will also 6988** be invoked if the call to sqlite3_create_module_v2() fails. 6989** ^The sqlite3_create_module() 6990** interface is equivalent to sqlite3_create_module_v2() with a NULL 6991** destructor. 6992** 6993** ^If the third parameter (the pointer to the sqlite3_module object) is 6994** NULL then no new module is create and any existing modules with the 6995** same name are dropped. 6996** 6997** See also: [sqlite3_drop_modules()] 6998*/ 6999int sqlite3_create_module( 7000 sqlite3 *db, /* SQLite connection to register module with */ 7001 const char *zName, /* Name of the module */ 7002 const sqlite3_module *p, /* Methods for the module */ 7003 void *pClientData /* Client data for xCreate/xConnect */ 7004); 7005int sqlite3_create_module_v2( 7006 sqlite3 *db, /* SQLite connection to register module with */ 7007 const char *zName, /* Name of the module */ 7008 const sqlite3_module *p, /* Methods for the module */ 7009 void *pClientData, /* Client data for xCreate/xConnect */ 7010 void(*xDestroy)(void*) /* Module destructor function */ 7011); 7012 7013/* 7014** CAPI3REF: Remove Unnecessary Virtual Table Implementations 7015** METHOD: sqlite3 7016** 7017** ^The sqlite3_drop_modules(D,L) interface removes all virtual 7018** table modules from database connection D except those named on list L. 7019** The L parameter must be either NULL or a pointer to an array of pointers 7020** to strings where the array is terminated by a single NULL pointer. 7021** ^If the L parameter is NULL, then all virtual table modules are removed. 7022** 7023** See also: [sqlite3_create_module()] 7024*/ 7025int sqlite3_drop_modules( 7026 sqlite3 *db, /* Remove modules from this connection */ 7027 const char **azKeep /* Except, do not remove the ones named here */ 7028); 7029 7030/* 7031** CAPI3REF: Virtual Table Instance Object 7032** KEYWORDS: sqlite3_vtab 7033** 7034** Every [virtual table module] implementation uses a subclass 7035** of this object to describe a particular instance 7036** of the [virtual table]. Each subclass will 7037** be tailored to the specific needs of the module implementation. 7038** The purpose of this superclass is to define certain fields that are 7039** common to all module implementations. 7040** 7041** ^Virtual tables methods can set an error message by assigning a 7042** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 7043** take care that any prior string is freed by a call to [sqlite3_free()] 7044** prior to assigning a new string to zErrMsg. ^After the error message 7045** is delivered up to the client application, the string will be automatically 7046** freed by sqlite3_free() and the zErrMsg field will be zeroed. 7047*/ 7048struct sqlite3_vtab { 7049 const sqlite3_module *pModule; /* The module for this virtual table */ 7050 int nRef; /* Number of open cursors */ 7051 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 7052 /* Virtual table implementations will typically add additional fields */ 7053}; 7054 7055/* 7056** CAPI3REF: Virtual Table Cursor Object 7057** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 7058** 7059** Every [virtual table module] implementation uses a subclass of the 7060** following structure to describe cursors that point into the 7061** [virtual table] and are used 7062** to loop through the virtual table. Cursors are created using the 7063** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 7064** by the [sqlite3_module.xClose | xClose] method. Cursors are used 7065** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 7066** of the module. Each module implementation will define 7067** the content of a cursor structure to suit its own needs. 7068** 7069** This superclass exists in order to define fields of the cursor that 7070** are common to all implementations. 7071*/ 7072struct sqlite3_vtab_cursor { 7073 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 7074 /* Virtual table implementations will typically add additional fields */ 7075}; 7076 7077/* 7078** CAPI3REF: Declare The Schema Of A Virtual Table 7079** 7080** ^The [xCreate] and [xConnect] methods of a 7081** [virtual table module] call this interface 7082** to declare the format (the names and datatypes of the columns) of 7083** the virtual tables they implement. 7084*/ 7085int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 7086 7087/* 7088** CAPI3REF: Overload A Function For A Virtual Table 7089** METHOD: sqlite3 7090** 7091** ^(Virtual tables can provide alternative implementations of functions 7092** using the [xFindFunction] method of the [virtual table module]. 7093** But global versions of those functions 7094** must exist in order to be overloaded.)^ 7095** 7096** ^(This API makes sure a global version of a function with a particular 7097** name and number of parameters exists. If no such function exists 7098** before this API is called, a new function is created.)^ ^The implementation 7099** of the new function always causes an exception to be thrown. So 7100** the new function is not good for anything by itself. Its only 7101** purpose is to be a placeholder function that can be overloaded 7102** by a [virtual table]. 7103*/ 7104int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 7105 7106/* 7107** The interface to the virtual-table mechanism defined above (back up 7108** to a comment remarkably similar to this one) is currently considered 7109** to be experimental. The interface might change in incompatible ways. 7110** If this is a problem for you, do not use the interface at this time. 7111** 7112** When the virtual-table mechanism stabilizes, we will declare the 7113** interface fixed, support it indefinitely, and remove this comment. 7114*/ 7115 7116/* 7117** CAPI3REF: A Handle To An Open BLOB 7118** KEYWORDS: {BLOB handle} {BLOB handles} 7119** 7120** An instance of this object represents an open BLOB on which 7121** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 7122** ^Objects of this type are created by [sqlite3_blob_open()] 7123** and destroyed by [sqlite3_blob_close()]. 7124** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 7125** can be used to read or write small subsections of the BLOB. 7126** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 7127*/ 7128typedef struct sqlite3_blob sqlite3_blob; 7129 7130/* 7131** CAPI3REF: Open A BLOB For Incremental I/O 7132** METHOD: sqlite3 7133** CONSTRUCTOR: sqlite3_blob 7134** 7135** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 7136** in row iRow, column zColumn, table zTable in database zDb; 7137** in other words, the same BLOB that would be selected by: 7138** 7139** <pre> 7140** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 7141** </pre>)^ 7142** 7143** ^(Parameter zDb is not the filename that contains the database, but 7144** rather the symbolic name of the database. For attached databases, this is 7145** the name that appears after the AS keyword in the [ATTACH] statement. 7146** For the main database file, the database name is "main". For TEMP 7147** tables, the database name is "temp".)^ 7148** 7149** ^If the flags parameter is non-zero, then the BLOB is opened for read 7150** and write access. ^If the flags parameter is zero, the BLOB is opened for 7151** read-only access. 7152** 7153** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 7154** in *ppBlob. Otherwise an [error code] is returned and, unless the error 7155** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 7156** the API is not misused, it is always safe to call [sqlite3_blob_close()] 7157** on *ppBlob after this function it returns. 7158** 7159** This function fails with SQLITE_ERROR if any of the following are true: 7160** <ul> 7161** <li> ^(Database zDb does not exist)^, 7162** <li> ^(Table zTable does not exist within database zDb)^, 7163** <li> ^(Table zTable is a WITHOUT ROWID table)^, 7164** <li> ^(Column zColumn does not exist)^, 7165** <li> ^(Row iRow is not present in the table)^, 7166** <li> ^(The specified column of row iRow contains a value that is not 7167** a TEXT or BLOB value)^, 7168** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 7169** constraint and the blob is being opened for read/write access)^, 7170** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 7171** column zColumn is part of a [child key] definition and the blob is 7172** being opened for read/write access)^. 7173** </ul> 7174** 7175** ^Unless it returns SQLITE_MISUSE, this function sets the 7176** [database connection] error code and message accessible via 7177** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7178** 7179** A BLOB referenced by sqlite3_blob_open() may be read using the 7180** [sqlite3_blob_read()] interface and modified by using 7181** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 7182** different row of the same table using the [sqlite3_blob_reopen()] 7183** interface. However, the column, table, or database of a [BLOB handle] 7184** cannot be changed after the [BLOB handle] is opened. 7185** 7186** ^(If the row that a BLOB handle points to is modified by an 7187** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 7188** then the BLOB handle is marked as "expired". 7189** This is true if any column of the row is changed, even a column 7190** other than the one the BLOB handle is open on.)^ 7191** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 7192** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 7193** ^(Changes written into a BLOB prior to the BLOB expiring are not 7194** rolled back by the expiration of the BLOB. Such changes will eventually 7195** commit if the transaction continues to completion.)^ 7196** 7197** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 7198** the opened blob. ^The size of a blob may not be changed by this 7199** interface. Use the [UPDATE] SQL command to change the size of a 7200** blob. 7201** 7202** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 7203** and the built-in [zeroblob] SQL function may be used to create a 7204** zero-filled blob to read or write using the incremental-blob interface. 7205** 7206** To avoid a resource leak, every open [BLOB handle] should eventually 7207** be released by a call to [sqlite3_blob_close()]. 7208** 7209** See also: [sqlite3_blob_close()], 7210** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 7211** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 7212*/ 7213int sqlite3_blob_open( 7214 sqlite3*, 7215 const char *zDb, 7216 const char *zTable, 7217 const char *zColumn, 7218 sqlite3_int64 iRow, 7219 int flags, 7220 sqlite3_blob **ppBlob 7221); 7222 7223/* 7224** CAPI3REF: Move a BLOB Handle to a New Row 7225** METHOD: sqlite3_blob 7226** 7227** ^This function is used to move an existing [BLOB handle] so that it points 7228** to a different row of the same database table. ^The new row is identified 7229** by the rowid value passed as the second argument. Only the row can be 7230** changed. ^The database, table and column on which the blob handle is open 7231** remain the same. Moving an existing [BLOB handle] to a new row is 7232** faster than closing the existing handle and opening a new one. 7233** 7234** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 7235** it must exist and there must be either a blob or text value stored in 7236** the nominated column.)^ ^If the new row is not present in the table, or if 7237** it does not contain a blob or text value, or if another error occurs, an 7238** SQLite error code is returned and the blob handle is considered aborted. 7239** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 7240** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 7241** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 7242** always returns zero. 7243** 7244** ^This function sets the database handle error code and message. 7245*/ 7246int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 7247 7248/* 7249** CAPI3REF: Close A BLOB Handle 7250** DESTRUCTOR: sqlite3_blob 7251** 7252** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 7253** unconditionally. Even if this routine returns an error code, the 7254** handle is still closed.)^ 7255** 7256** ^If the blob handle being closed was opened for read-write access, and if 7257** the database is in auto-commit mode and there are no other open read-write 7258** blob handles or active write statements, the current transaction is 7259** committed. ^If an error occurs while committing the transaction, an error 7260** code is returned and the transaction rolled back. 7261** 7262** Calling this function with an argument that is not a NULL pointer or an 7263** open blob handle results in undefined behaviour. ^Calling this routine 7264** with a null pointer (such as would be returned by a failed call to 7265** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 7266** is passed a valid open blob handle, the values returned by the 7267** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 7268*/ 7269int sqlite3_blob_close(sqlite3_blob *); 7270 7271/* 7272** CAPI3REF: Return The Size Of An Open BLOB 7273** METHOD: sqlite3_blob 7274** 7275** ^Returns the size in bytes of the BLOB accessible via the 7276** successfully opened [BLOB handle] in its only argument. ^The 7277** incremental blob I/O routines can only read or overwriting existing 7278** blob content; they cannot change the size of a blob. 7279** 7280** This routine only works on a [BLOB handle] which has been created 7281** by a prior successful call to [sqlite3_blob_open()] and which has not 7282** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7283** to this routine results in undefined and probably undesirable behavior. 7284*/ 7285int sqlite3_blob_bytes(sqlite3_blob *); 7286 7287/* 7288** CAPI3REF: Read Data From A BLOB Incrementally 7289** METHOD: sqlite3_blob 7290** 7291** ^(This function is used to read data from an open [BLOB handle] into a 7292** caller-supplied buffer. N bytes of data are copied into buffer Z 7293** from the open BLOB, starting at offset iOffset.)^ 7294** 7295** ^If offset iOffset is less than N bytes from the end of the BLOB, 7296** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 7297** less than zero, [SQLITE_ERROR] is returned and no data is read. 7298** ^The size of the blob (and hence the maximum value of N+iOffset) 7299** can be determined using the [sqlite3_blob_bytes()] interface. 7300** 7301** ^An attempt to read from an expired [BLOB handle] fails with an 7302** error code of [SQLITE_ABORT]. 7303** 7304** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 7305** Otherwise, an [error code] or an [extended error code] is returned.)^ 7306** 7307** This routine only works on a [BLOB handle] which has been created 7308** by a prior successful call to [sqlite3_blob_open()] and which has not 7309** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7310** to this routine results in undefined and probably undesirable behavior. 7311** 7312** See also: [sqlite3_blob_write()]. 7313*/ 7314int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 7315 7316/* 7317** CAPI3REF: Write Data Into A BLOB Incrementally 7318** METHOD: sqlite3_blob 7319** 7320** ^(This function is used to write data into an open [BLOB handle] from a 7321** caller-supplied buffer. N bytes of data are copied from the buffer Z 7322** into the open BLOB, starting at offset iOffset.)^ 7323** 7324** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 7325** Otherwise, an [error code] or an [extended error code] is returned.)^ 7326** ^Unless SQLITE_MISUSE is returned, this function sets the 7327** [database connection] error code and message accessible via 7328** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7329** 7330** ^If the [BLOB handle] passed as the first argument was not opened for 7331** writing (the flags parameter to [sqlite3_blob_open()] was zero), 7332** this function returns [SQLITE_READONLY]. 7333** 7334** This function may only modify the contents of the BLOB; it is 7335** not possible to increase the size of a BLOB using this API. 7336** ^If offset iOffset is less than N bytes from the end of the BLOB, 7337** [SQLITE_ERROR] is returned and no data is written. The size of the 7338** BLOB (and hence the maximum value of N+iOffset) can be determined 7339** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 7340** than zero [SQLITE_ERROR] is returned and no data is written. 7341** 7342** ^An attempt to write to an expired [BLOB handle] fails with an 7343** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 7344** before the [BLOB handle] expired are not rolled back by the 7345** expiration of the handle, though of course those changes might 7346** have been overwritten by the statement that expired the BLOB handle 7347** or by other independent statements. 7348** 7349** This routine only works on a [BLOB handle] which has been created 7350** by a prior successful call to [sqlite3_blob_open()] and which has not 7351** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7352** to this routine results in undefined and probably undesirable behavior. 7353** 7354** See also: [sqlite3_blob_read()]. 7355*/ 7356int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 7357 7358/* 7359** CAPI3REF: Virtual File System Objects 7360** 7361** A virtual filesystem (VFS) is an [sqlite3_vfs] object 7362** that SQLite uses to interact 7363** with the underlying operating system. Most SQLite builds come with a 7364** single default VFS that is appropriate for the host computer. 7365** New VFSes can be registered and existing VFSes can be unregistered. 7366** The following interfaces are provided. 7367** 7368** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 7369** ^Names are case sensitive. 7370** ^Names are zero-terminated UTF-8 strings. 7371** ^If there is no match, a NULL pointer is returned. 7372** ^If zVfsName is NULL then the default VFS is returned. 7373** 7374** ^New VFSes are registered with sqlite3_vfs_register(). 7375** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 7376** ^The same VFS can be registered multiple times without injury. 7377** ^To make an existing VFS into the default VFS, register it again 7378** with the makeDflt flag set. If two different VFSes with the 7379** same name are registered, the behavior is undefined. If a 7380** VFS is registered with a name that is NULL or an empty string, 7381** then the behavior is undefined. 7382** 7383** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 7384** ^(If the default VFS is unregistered, another VFS is chosen as 7385** the default. The choice for the new VFS is arbitrary.)^ 7386*/ 7387sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 7388int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 7389int sqlite3_vfs_unregister(sqlite3_vfs*); 7390 7391/* 7392** CAPI3REF: Mutexes 7393** 7394** The SQLite core uses these routines for thread 7395** synchronization. Though they are intended for internal 7396** use by SQLite, code that links against SQLite is 7397** permitted to use any of these routines. 7398** 7399** The SQLite source code contains multiple implementations 7400** of these mutex routines. An appropriate implementation 7401** is selected automatically at compile-time. The following 7402** implementations are available in the SQLite core: 7403** 7404** <ul> 7405** <li> SQLITE_MUTEX_PTHREADS 7406** <li> SQLITE_MUTEX_W32 7407** <li> SQLITE_MUTEX_NOOP 7408** </ul> 7409** 7410** The SQLITE_MUTEX_NOOP implementation is a set of routines 7411** that does no real locking and is appropriate for use in 7412** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 7413** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 7414** and Windows. 7415** 7416** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 7417** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 7418** implementation is included with the library. In this case the 7419** application must supply a custom mutex implementation using the 7420** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 7421** before calling sqlite3_initialize() or any other public sqlite3_ 7422** function that calls sqlite3_initialize(). 7423** 7424** ^The sqlite3_mutex_alloc() routine allocates a new 7425** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 7426** routine returns NULL if it is unable to allocate the requested 7427** mutex. The argument to sqlite3_mutex_alloc() must one of these 7428** integer constants: 7429** 7430** <ul> 7431** <li> SQLITE_MUTEX_FAST 7432** <li> SQLITE_MUTEX_RECURSIVE 7433** <li> SQLITE_MUTEX_STATIC_MAIN 7434** <li> SQLITE_MUTEX_STATIC_MEM 7435** <li> SQLITE_MUTEX_STATIC_OPEN 7436** <li> SQLITE_MUTEX_STATIC_PRNG 7437** <li> SQLITE_MUTEX_STATIC_LRU 7438** <li> SQLITE_MUTEX_STATIC_PMEM 7439** <li> SQLITE_MUTEX_STATIC_APP1 7440** <li> SQLITE_MUTEX_STATIC_APP2 7441** <li> SQLITE_MUTEX_STATIC_APP3 7442** <li> SQLITE_MUTEX_STATIC_VFS1 7443** <li> SQLITE_MUTEX_STATIC_VFS2 7444** <li> SQLITE_MUTEX_STATIC_VFS3 7445** </ul> 7446** 7447** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 7448** cause sqlite3_mutex_alloc() to create 7449** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 7450** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 7451** The mutex implementation does not need to make a distinction 7452** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 7453** not want to. SQLite will only request a recursive mutex in 7454** cases where it really needs one. If a faster non-recursive mutex 7455** implementation is available on the host platform, the mutex subsystem 7456** might return such a mutex in response to SQLITE_MUTEX_FAST. 7457** 7458** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 7459** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 7460** a pointer to a static preexisting mutex. ^Nine static mutexes are 7461** used by the current version of SQLite. Future versions of SQLite 7462** may add additional static mutexes. Static mutexes are for internal 7463** use by SQLite only. Applications that use SQLite mutexes should 7464** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 7465** SQLITE_MUTEX_RECURSIVE. 7466** 7467** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 7468** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 7469** returns a different mutex on every call. ^For the static 7470** mutex types, the same mutex is returned on every call that has 7471** the same type number. 7472** 7473** ^The sqlite3_mutex_free() routine deallocates a previously 7474** allocated dynamic mutex. Attempting to deallocate a static 7475** mutex results in undefined behavior. 7476** 7477** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 7478** to enter a mutex. ^If another thread is already within the mutex, 7479** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 7480** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 7481** upon successful entry. ^(Mutexes created using 7482** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 7483** In such cases, the 7484** mutex must be exited an equal number of times before another thread 7485** can enter.)^ If the same thread tries to enter any mutex other 7486** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 7487** 7488** ^(Some systems (for example, Windows 95) do not support the operation 7489** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 7490** will always return SQLITE_BUSY. The SQLite core only ever uses 7491** sqlite3_mutex_try() as an optimization so this is acceptable 7492** behavior.)^ 7493** 7494** ^The sqlite3_mutex_leave() routine exits a mutex that was 7495** previously entered by the same thread. The behavior 7496** is undefined if the mutex is not currently entered by the 7497** calling thread or is not currently allocated. 7498** 7499** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 7500** sqlite3_mutex_leave() is a NULL pointer, then all three routines 7501** behave as no-ops. 7502** 7503** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 7504*/ 7505sqlite3_mutex *sqlite3_mutex_alloc(int); 7506void sqlite3_mutex_free(sqlite3_mutex*); 7507void sqlite3_mutex_enter(sqlite3_mutex*); 7508int sqlite3_mutex_try(sqlite3_mutex*); 7509void sqlite3_mutex_leave(sqlite3_mutex*); 7510 7511/* 7512** CAPI3REF: Mutex Methods Object 7513** 7514** An instance of this structure defines the low-level routines 7515** used to allocate and use mutexes. 7516** 7517** Usually, the default mutex implementations provided by SQLite are 7518** sufficient, however the application has the option of substituting a custom 7519** implementation for specialized deployments or systems for which SQLite 7520** does not provide a suitable implementation. In this case, the application 7521** creates and populates an instance of this structure to pass 7522** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 7523** Additionally, an instance of this structure can be used as an 7524** output variable when querying the system for the current mutex 7525** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 7526** 7527** ^The xMutexInit method defined by this structure is invoked as 7528** part of system initialization by the sqlite3_initialize() function. 7529** ^The xMutexInit routine is called by SQLite exactly once for each 7530** effective call to [sqlite3_initialize()]. 7531** 7532** ^The xMutexEnd method defined by this structure is invoked as 7533** part of system shutdown by the sqlite3_shutdown() function. The 7534** implementation of this method is expected to release all outstanding 7535** resources obtained by the mutex methods implementation, especially 7536** those obtained by the xMutexInit method. ^The xMutexEnd() 7537** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 7538** 7539** ^(The remaining seven methods defined by this structure (xMutexAlloc, 7540** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 7541** xMutexNotheld) implement the following interfaces (respectively): 7542** 7543** <ul> 7544** <li> [sqlite3_mutex_alloc()] </li> 7545** <li> [sqlite3_mutex_free()] </li> 7546** <li> [sqlite3_mutex_enter()] </li> 7547** <li> [sqlite3_mutex_try()] </li> 7548** <li> [sqlite3_mutex_leave()] </li> 7549** <li> [sqlite3_mutex_held()] </li> 7550** <li> [sqlite3_mutex_notheld()] </li> 7551** </ul>)^ 7552** 7553** The only difference is that the public sqlite3_XXX functions enumerated 7554** above silently ignore any invocations that pass a NULL pointer instead 7555** of a valid mutex handle. The implementations of the methods defined 7556** by this structure are not required to handle this case. The results 7557** of passing a NULL pointer instead of a valid mutex handle are undefined 7558** (i.e. it is acceptable to provide an implementation that segfaults if 7559** it is passed a NULL pointer). 7560** 7561** The xMutexInit() method must be threadsafe. It must be harmless to 7562** invoke xMutexInit() multiple times within the same process and without 7563** intervening calls to xMutexEnd(). Second and subsequent calls to 7564** xMutexInit() must be no-ops. 7565** 7566** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 7567** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 7568** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 7569** memory allocation for a fast or recursive mutex. 7570** 7571** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 7572** called, but only if the prior call to xMutexInit returned SQLITE_OK. 7573** If xMutexInit fails in any way, it is expected to clean up after itself 7574** prior to returning. 7575*/ 7576typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 7577struct sqlite3_mutex_methods { 7578 int (*xMutexInit)(void); 7579 int (*xMutexEnd)(void); 7580 sqlite3_mutex *(*xMutexAlloc)(int); 7581 void (*xMutexFree)(sqlite3_mutex *); 7582 void (*xMutexEnter)(sqlite3_mutex *); 7583 int (*xMutexTry)(sqlite3_mutex *); 7584 void (*xMutexLeave)(sqlite3_mutex *); 7585 int (*xMutexHeld)(sqlite3_mutex *); 7586 int (*xMutexNotheld)(sqlite3_mutex *); 7587}; 7588 7589/* 7590** CAPI3REF: Mutex Verification Routines 7591** 7592** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 7593** are intended for use inside assert() statements. The SQLite core 7594** never uses these routines except inside an assert() and applications 7595** are advised to follow the lead of the core. The SQLite core only 7596** provides implementations for these routines when it is compiled 7597** with the SQLITE_DEBUG flag. External mutex implementations 7598** are only required to provide these routines if SQLITE_DEBUG is 7599** defined and if NDEBUG is not defined. 7600** 7601** These routines should return true if the mutex in their argument 7602** is held or not held, respectively, by the calling thread. 7603** 7604** The implementation is not required to provide versions of these 7605** routines that actually work. If the implementation does not provide working 7606** versions of these routines, it should at least provide stubs that always 7607** return true so that one does not get spurious assertion failures. 7608** 7609** If the argument to sqlite3_mutex_held() is a NULL pointer then 7610** the routine should return 1. This seems counter-intuitive since 7611** clearly the mutex cannot be held if it does not exist. But 7612** the reason the mutex does not exist is because the build is not 7613** using mutexes. And we do not want the assert() containing the 7614** call to sqlite3_mutex_held() to fail, so a non-zero return is 7615** the appropriate thing to do. The sqlite3_mutex_notheld() 7616** interface should also return 1 when given a NULL pointer. 7617*/ 7618#ifndef NDEBUG 7619int sqlite3_mutex_held(sqlite3_mutex*); 7620int sqlite3_mutex_notheld(sqlite3_mutex*); 7621#endif 7622 7623/* 7624** CAPI3REF: Mutex Types 7625** 7626** The [sqlite3_mutex_alloc()] interface takes a single argument 7627** which is one of these integer constants. 7628** 7629** The set of static mutexes may change from one SQLite release to the 7630** next. Applications that override the built-in mutex logic must be 7631** prepared to accommodate additional static mutexes. 7632*/ 7633#define SQLITE_MUTEX_FAST 0 7634#define SQLITE_MUTEX_RECURSIVE 1 7635#define SQLITE_MUTEX_STATIC_MAIN 2 7636#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 7637#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 7638#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 7639#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 7640#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 7641#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 7642#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 7643#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 7644#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 7645#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 7646#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 7647#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 7648#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 7649 7650/* Legacy compatibility: */ 7651#define SQLITE_MUTEX_STATIC_MASTER 2 7652 7653 7654/* 7655** CAPI3REF: Retrieve the mutex for a database connection 7656** METHOD: sqlite3 7657** 7658** ^This interface returns a pointer the [sqlite3_mutex] object that 7659** serializes access to the [database connection] given in the argument 7660** when the [threading mode] is Serialized. 7661** ^If the [threading mode] is Single-thread or Multi-thread then this 7662** routine returns a NULL pointer. 7663*/ 7664sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 7665 7666/* 7667** CAPI3REF: Low-Level Control Of Database Files 7668** METHOD: sqlite3 7669** KEYWORDS: {file control} 7670** 7671** ^The [sqlite3_file_control()] interface makes a direct call to the 7672** xFileControl method for the [sqlite3_io_methods] object associated 7673** with a particular database identified by the second argument. ^The 7674** name of the database is "main" for the main database or "temp" for the 7675** TEMP database, or the name that appears after the AS keyword for 7676** databases that are added using the [ATTACH] SQL command. 7677** ^A NULL pointer can be used in place of "main" to refer to the 7678** main database file. 7679** ^The third and fourth parameters to this routine 7680** are passed directly through to the second and third parameters of 7681** the xFileControl method. ^The return value of the xFileControl 7682** method becomes the return value of this routine. 7683** 7684** A few opcodes for [sqlite3_file_control()] are handled directly 7685** by the SQLite core and never invoke the 7686** sqlite3_io_methods.xFileControl method. 7687** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 7688** a pointer to the underlying [sqlite3_file] object to be written into 7689** the space pointed to by the 4th parameter. The 7690** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns 7691** the [sqlite3_file] object associated with the journal file instead of 7692** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns 7693** a pointer to the underlying [sqlite3_vfs] object for the file. 7694** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter 7695** from the pager. 7696** 7697** ^If the second parameter (zDbName) does not match the name of any 7698** open database file, then SQLITE_ERROR is returned. ^This error 7699** code is not remembered and will not be recalled by [sqlite3_errcode()] 7700** or [sqlite3_errmsg()]. The underlying xFileControl method might 7701** also return SQLITE_ERROR. There is no way to distinguish between 7702** an incorrect zDbName and an SQLITE_ERROR return from the underlying 7703** xFileControl method. 7704** 7705** See also: [file control opcodes] 7706*/ 7707int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 7708 7709/* 7710** CAPI3REF: Testing Interface 7711** 7712** ^The sqlite3_test_control() interface is used to read out internal 7713** state of SQLite and to inject faults into SQLite for testing 7714** purposes. ^The first parameter is an operation code that determines 7715** the number, meaning, and operation of all subsequent parameters. 7716** 7717** This interface is not for use by applications. It exists solely 7718** for verifying the correct operation of the SQLite library. Depending 7719** on how the SQLite library is compiled, this interface might not exist. 7720** 7721** The details of the operation codes, their meanings, the parameters 7722** they take, and what they do are all subject to change without notice. 7723** Unlike most of the SQLite API, this function is not guaranteed to 7724** operate consistently from one release to the next. 7725*/ 7726int sqlite3_test_control(int op, ...); 7727 7728/* 7729** CAPI3REF: Testing Interface Operation Codes 7730** 7731** These constants are the valid operation code parameters used 7732** as the first argument to [sqlite3_test_control()]. 7733** 7734** These parameters and their meanings are subject to change 7735** without notice. These values are for testing purposes only. 7736** Applications should not use any of these parameters or the 7737** [sqlite3_test_control()] interface. 7738*/ 7739#define SQLITE_TESTCTRL_FIRST 5 7740#define SQLITE_TESTCTRL_PRNG_SAVE 5 7741#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7742#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */ 7743#define SQLITE_TESTCTRL_SEEK_COUNT 7 7744#define SQLITE_TESTCTRL_BITVEC_TEST 8 7745#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7746#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7747#define SQLITE_TESTCTRL_PENDING_BYTE 11 7748#define SQLITE_TESTCTRL_ASSERT 12 7749#define SQLITE_TESTCTRL_ALWAYS 13 7750#define SQLITE_TESTCTRL_RESERVE 14 /* NOT USED */ 7751#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7752#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */ 7753#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7754#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17 7755#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7756#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7757#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7758#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7759#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7760#define SQLITE_TESTCTRL_BYTEORDER 22 7761#define SQLITE_TESTCTRL_ISINIT 23 7762#define SQLITE_TESTCTRL_SORTER_MMAP 24 7763#define SQLITE_TESTCTRL_IMPOSTER 25 7764#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7765#define SQLITE_TESTCTRL_RESULT_INTREAL 27 7766#define SQLITE_TESTCTRL_PRNG_SEED 28 7767#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29 7768#define SQLITE_TESTCTRL_LAST 29 /* Largest TESTCTRL */ 7769 7770/* 7771** CAPI3REF: SQL Keyword Checking 7772** 7773** These routines provide access to the set of SQL language keywords 7774** recognized by SQLite. Applications can uses these routines to determine 7775** whether or not a specific identifier needs to be escaped (for example, 7776** by enclosing in double-quotes) so as not to confuse the parser. 7777** 7778** The sqlite3_keyword_count() interface returns the number of distinct 7779** keywords understood by SQLite. 7780** 7781** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and 7782** makes *Z point to that keyword expressed as UTF8 and writes the number 7783** of bytes in the keyword into *L. The string that *Z points to is not 7784** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns 7785** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z 7786** or L are NULL or invalid pointers then calls to 7787** sqlite3_keyword_name(N,Z,L) result in undefined behavior. 7788** 7789** The sqlite3_keyword_check(Z,L) interface checks to see whether or not 7790** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero 7791** if it is and zero if not. 7792** 7793** The parser used by SQLite is forgiving. It is often possible to use 7794** a keyword as an identifier as long as such use does not result in a 7795** parsing ambiguity. For example, the statement 7796** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and 7797** creates a new table named "BEGIN" with three columns named 7798** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid 7799** using keywords as identifiers. Common techniques used to avoid keyword 7800** name collisions include: 7801** <ul> 7802** <li> Put all identifier names inside double-quotes. This is the official 7803** SQL way to escape identifier names. 7804** <li> Put identifier names inside [...]. This is not standard SQL, 7805** but it is what SQL Server does and so lots of programmers use this 7806** technique. 7807** <li> Begin every identifier with the letter "Z" as no SQL keywords start 7808** with "Z". 7809** <li> Include a digit somewhere in every identifier name. 7810** </ul> 7811** 7812** Note that the number of keywords understood by SQLite can depend on 7813** compile-time options. For example, "VACUUM" is not a keyword if 7814** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also, 7815** new keywords may be added to future releases of SQLite. 7816*/ 7817int sqlite3_keyword_count(void); 7818int sqlite3_keyword_name(int,const char**,int*); 7819int sqlite3_keyword_check(const char*,int); 7820 7821/* 7822** CAPI3REF: Dynamic String Object 7823** KEYWORDS: {dynamic string} 7824** 7825** An instance of the sqlite3_str object contains a dynamically-sized 7826** string under construction. 7827** 7828** The lifecycle of an sqlite3_str object is as follows: 7829** <ol> 7830** <li> ^The sqlite3_str object is created using [sqlite3_str_new()]. 7831** <li> ^Text is appended to the sqlite3_str object using various 7832** methods, such as [sqlite3_str_appendf()]. 7833** <li> ^The sqlite3_str object is destroyed and the string it created 7834** is returned using the [sqlite3_str_finish()] interface. 7835** </ol> 7836*/ 7837typedef struct sqlite3_str sqlite3_str; 7838 7839/* 7840** CAPI3REF: Create A New Dynamic String Object 7841** CONSTRUCTOR: sqlite3_str 7842** 7843** ^The [sqlite3_str_new(D)] interface allocates and initializes 7844** a new [sqlite3_str] object. To avoid memory leaks, the object returned by 7845** [sqlite3_str_new()] must be freed by a subsequent call to 7846** [sqlite3_str_finish(X)]. 7847** 7848** ^The [sqlite3_str_new(D)] interface always returns a pointer to a 7849** valid [sqlite3_str] object, though in the event of an out-of-memory 7850** error the returned object might be a special singleton that will 7851** silently reject new text, always return SQLITE_NOMEM from 7852** [sqlite3_str_errcode()], always return 0 for 7853** [sqlite3_str_length()], and always return NULL from 7854** [sqlite3_str_finish(X)]. It is always safe to use the value 7855** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter 7856** to any of the other [sqlite3_str] methods. 7857** 7858** The D parameter to [sqlite3_str_new(D)] may be NULL. If the 7859** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum 7860** length of the string contained in the [sqlite3_str] object will be 7861** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead 7862** of [SQLITE_MAX_LENGTH]. 7863*/ 7864sqlite3_str *sqlite3_str_new(sqlite3*); 7865 7866/* 7867** CAPI3REF: Finalize A Dynamic String 7868** DESTRUCTOR: sqlite3_str 7869** 7870** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X 7871** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()] 7872** that contains the constructed string. The calling application should 7873** pass the returned value to [sqlite3_free()] to avoid a memory leak. 7874** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any 7875** errors were encountered during construction of the string. ^The 7876** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the 7877** string in [sqlite3_str] object X is zero bytes long. 7878*/ 7879char *sqlite3_str_finish(sqlite3_str*); 7880 7881/* 7882** CAPI3REF: Add Content To A Dynamic String 7883** METHOD: sqlite3_str 7884** 7885** These interfaces add content to an sqlite3_str object previously obtained 7886** from [sqlite3_str_new()]. 7887** 7888** ^The [sqlite3_str_appendf(X,F,...)] and 7889** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf] 7890** functionality of SQLite to append formatted text onto the end of 7891** [sqlite3_str] object X. 7892** 7893** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S 7894** onto the end of the [sqlite3_str] object X. N must be non-negative. 7895** S must contain at least N non-zero bytes of content. To append a 7896** zero-terminated string in its entirety, use the [sqlite3_str_appendall()] 7897** method instead. 7898** 7899** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of 7900** zero-terminated string S onto the end of [sqlite3_str] object X. 7901** 7902** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the 7903** single-byte character C onto the end of [sqlite3_str] object X. 7904** ^This method can be used, for example, to add whitespace indentation. 7905** 7906** ^The [sqlite3_str_reset(X)] method resets the string under construction 7907** inside [sqlite3_str] object X back to zero bytes in length. 7908** 7909** These methods do not return a result code. ^If an error occurs, that fact 7910** is recorded in the [sqlite3_str] object and can be recovered by a 7911** subsequent call to [sqlite3_str_errcode(X)]. 7912*/ 7913void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...); 7914void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list); 7915void sqlite3_str_append(sqlite3_str*, const char *zIn, int N); 7916void sqlite3_str_appendall(sqlite3_str*, const char *zIn); 7917void sqlite3_str_appendchar(sqlite3_str*, int N, char C); 7918void sqlite3_str_reset(sqlite3_str*); 7919 7920/* 7921** CAPI3REF: Status Of A Dynamic String 7922** METHOD: sqlite3_str 7923** 7924** These interfaces return the current status of an [sqlite3_str] object. 7925** 7926** ^If any prior errors have occurred while constructing the dynamic string 7927** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return 7928** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns 7929** [SQLITE_NOMEM] following any out-of-memory error, or 7930** [SQLITE_TOOBIG] if the size of the dynamic string exceeds 7931** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors. 7932** 7933** ^The [sqlite3_str_length(X)] method returns the current length, in bytes, 7934** of the dynamic string under construction in [sqlite3_str] object X. 7935** ^The length returned by [sqlite3_str_length(X)] does not include the 7936** zero-termination byte. 7937** 7938** ^The [sqlite3_str_value(X)] method returns a pointer to the current 7939** content of the dynamic string under construction in X. The value 7940** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X 7941** and might be freed or altered by any subsequent method on the same 7942** [sqlite3_str] object. Applications must not used the pointer returned 7943** [sqlite3_str_value(X)] after any subsequent method call on the same 7944** object. ^Applications may change the content of the string returned 7945** by [sqlite3_str_value(X)] as long as they do not write into any bytes 7946** outside the range of 0 to [sqlite3_str_length(X)] and do not read or 7947** write any byte after any subsequent sqlite3_str method call. 7948*/ 7949int sqlite3_str_errcode(sqlite3_str*); 7950int sqlite3_str_length(sqlite3_str*); 7951char *sqlite3_str_value(sqlite3_str*); 7952 7953/* 7954** CAPI3REF: SQLite Runtime Status 7955** 7956** ^These interfaces are used to retrieve runtime status information 7957** about the performance of SQLite, and optionally to reset various 7958** highwater marks. ^The first argument is an integer code for 7959** the specific parameter to measure. ^(Recognized integer codes 7960** are of the form [status parameters | SQLITE_STATUS_...].)^ 7961** ^The current value of the parameter is returned into *pCurrent. 7962** ^The highest recorded value is returned in *pHighwater. ^If the 7963** resetFlag is true, then the highest record value is reset after 7964** *pHighwater is written. ^(Some parameters do not record the highest 7965** value. For those parameters 7966** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7967** ^(Other parameters record only the highwater mark and not the current 7968** value. For these latter parameters nothing is written into *pCurrent.)^ 7969** 7970** ^The sqlite3_status() and sqlite3_status64() routines return 7971** SQLITE_OK on success and a non-zero [error code] on failure. 7972** 7973** If either the current value or the highwater mark is too large to 7974** be represented by a 32-bit integer, then the values returned by 7975** sqlite3_status() are undefined. 7976** 7977** See also: [sqlite3_db_status()] 7978*/ 7979int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7980int sqlite3_status64( 7981 int op, 7982 sqlite3_int64 *pCurrent, 7983 sqlite3_int64 *pHighwater, 7984 int resetFlag 7985); 7986 7987 7988/* 7989** CAPI3REF: Status Parameters 7990** KEYWORDS: {status parameters} 7991** 7992** These integer constants designate various run-time status parameters 7993** that can be returned by [sqlite3_status()]. 7994** 7995** <dl> 7996** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7997** <dd>This parameter is the current amount of memory checked out 7998** using [sqlite3_malloc()], either directly or indirectly. The 7999** figure includes calls made to [sqlite3_malloc()] by the application 8000** and internal memory usage by the SQLite library. Auxiliary page-cache 8001** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 8002** this parameter. The amount returned is the sum of the allocation 8003** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 8004** 8005** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 8006** <dd>This parameter records the largest memory allocation request 8007** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 8008** internal equivalents). Only the value returned in the 8009** *pHighwater parameter to [sqlite3_status()] is of interest. 8010** The value written into the *pCurrent parameter is undefined.</dd>)^ 8011** 8012** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 8013** <dd>This parameter records the number of separate memory allocations 8014** currently checked out.</dd>)^ 8015** 8016** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 8017** <dd>This parameter returns the number of pages used out of the 8018** [pagecache memory allocator] that was configured using 8019** [SQLITE_CONFIG_PAGECACHE]. The 8020** value returned is in pages, not in bytes.</dd>)^ 8021** 8022** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 8023** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 8024** <dd>This parameter returns the number of bytes of page cache 8025** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 8026** buffer and where forced to overflow to [sqlite3_malloc()]. The 8027** returned value includes allocations that overflowed because they 8028** where too large (they were larger than the "sz" parameter to 8029** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 8030** no space was left in the page cache.</dd>)^ 8031** 8032** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 8033** <dd>This parameter records the largest memory allocation request 8034** handed to the [pagecache memory allocator]. Only the value returned in the 8035** *pHighwater parameter to [sqlite3_status()] is of interest. 8036** The value written into the *pCurrent parameter is undefined.</dd>)^ 8037** 8038** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 8039** <dd>No longer used.</dd> 8040** 8041** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 8042** <dd>No longer used.</dd> 8043** 8044** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 8045** <dd>No longer used.</dd> 8046** 8047** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 8048** <dd>The *pHighwater parameter records the deepest parser stack. 8049** The *pCurrent value is undefined. The *pHighwater value is only 8050** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 8051** </dl> 8052** 8053** New status parameters may be added from time to time. 8054*/ 8055#define SQLITE_STATUS_MEMORY_USED 0 8056#define SQLITE_STATUS_PAGECACHE_USED 1 8057#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 8058#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 8059#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 8060#define SQLITE_STATUS_MALLOC_SIZE 5 8061#define SQLITE_STATUS_PARSER_STACK 6 8062#define SQLITE_STATUS_PAGECACHE_SIZE 7 8063#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 8064#define SQLITE_STATUS_MALLOC_COUNT 9 8065 8066/* 8067** CAPI3REF: Database Connection Status 8068** METHOD: sqlite3 8069** 8070** ^This interface is used to retrieve runtime status information 8071** about a single [database connection]. ^The first argument is the 8072** database connection object to be interrogated. ^The second argument 8073** is an integer constant, taken from the set of 8074** [SQLITE_DBSTATUS options], that 8075** determines the parameter to interrogate. The set of 8076** [SQLITE_DBSTATUS options] is likely 8077** to grow in future releases of SQLite. 8078** 8079** ^The current value of the requested parameter is written into *pCur 8080** and the highest instantaneous value is written into *pHiwtr. ^If 8081** the resetFlg is true, then the highest instantaneous value is 8082** reset back down to the current value. 8083** 8084** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 8085** non-zero [error code] on failure. 8086** 8087** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 8088*/ 8089int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 8090 8091/* 8092** CAPI3REF: Status Parameters for database connections 8093** KEYWORDS: {SQLITE_DBSTATUS options} 8094** 8095** These constants are the available integer "verbs" that can be passed as 8096** the second argument to the [sqlite3_db_status()] interface. 8097** 8098** New verbs may be added in future releases of SQLite. Existing verbs 8099** might be discontinued. Applications should check the return code from 8100** [sqlite3_db_status()] to make sure that the call worked. 8101** The [sqlite3_db_status()] interface will return a non-zero error code 8102** if a discontinued or unsupported verb is invoked. 8103** 8104** <dl> 8105** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 8106** <dd>This parameter returns the number of lookaside memory slots currently 8107** checked out.</dd>)^ 8108** 8109** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 8110** <dd>This parameter returns the number of malloc attempts that were 8111** satisfied using lookaside memory. Only the high-water value is meaningful; 8112** the current value is always zero.)^ 8113** 8114** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 8115** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 8116** <dd>This parameter returns the number malloc attempts that might have 8117** been satisfied using lookaside memory but failed due to the amount of 8118** memory requested being larger than the lookaside slot size. 8119** Only the high-water value is meaningful; 8120** the current value is always zero.)^ 8121** 8122** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 8123** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 8124** <dd>This parameter returns the number malloc attempts that might have 8125** been satisfied using lookaside memory but failed due to all lookaside 8126** memory already being in use. 8127** Only the high-water value is meaningful; 8128** the current value is always zero.)^ 8129** 8130** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 8131** <dd>This parameter returns the approximate number of bytes of heap 8132** memory used by all pager caches associated with the database connection.)^ 8133** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 8134** 8135** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 8136** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 8137** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 8138** pager cache is shared between two or more connections the bytes of heap 8139** memory used by that pager cache is divided evenly between the attached 8140** connections.)^ In other words, if none of the pager caches associated 8141** with the database connection are shared, this request returns the same 8142** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 8143** shared, the value returned by this call will be smaller than that returned 8144** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 8145** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 8146** 8147** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 8148** <dd>This parameter returns the approximate number of bytes of heap 8149** memory used to store the schema for all databases associated 8150** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 8151** ^The full amount of memory used by the schemas is reported, even if the 8152** schema memory is shared with other database connections due to 8153** [shared cache mode] being enabled. 8154** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 8155** 8156** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 8157** <dd>This parameter returns the approximate number of bytes of heap 8158** and lookaside memory used by all prepared statements associated with 8159** the database connection.)^ 8160** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 8161** </dd> 8162** 8163** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 8164** <dd>This parameter returns the number of pager cache hits that have 8165** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 8166** is always 0. 8167** </dd> 8168** 8169** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 8170** <dd>This parameter returns the number of pager cache misses that have 8171** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 8172** is always 0. 8173** </dd> 8174** 8175** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 8176** <dd>This parameter returns the number of dirty cache entries that have 8177** been written to disk. Specifically, the number of pages written to the 8178** wal file in wal mode databases, or the number of pages written to the 8179** database file in rollback mode databases. Any pages written as part of 8180** transaction rollback or database recovery operations are not included. 8181** If an IO or other error occurs while writing a page to disk, the effect 8182** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 8183** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 8184** </dd> 8185** 8186** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 8187** <dd>This parameter returns the number of dirty cache entries that have 8188** been written to disk in the middle of a transaction due to the page 8189** cache overflowing. Transactions are more efficient if they are written 8190** to disk all at once. When pages spill mid-transaction, that introduces 8191** additional overhead. This parameter can be used help identify 8192** inefficiencies that can be resolved by increasing the cache size. 8193** </dd> 8194** 8195** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 8196** <dd>This parameter returns zero for the current value if and only if 8197** all foreign key constraints (deferred or immediate) have been 8198** resolved.)^ ^The highwater mark is always 0. 8199** </dd> 8200** </dl> 8201*/ 8202#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 8203#define SQLITE_DBSTATUS_CACHE_USED 1 8204#define SQLITE_DBSTATUS_SCHEMA_USED 2 8205#define SQLITE_DBSTATUS_STMT_USED 3 8206#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 8207#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 8208#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 8209#define SQLITE_DBSTATUS_CACHE_HIT 7 8210#define SQLITE_DBSTATUS_CACHE_MISS 8 8211#define SQLITE_DBSTATUS_CACHE_WRITE 9 8212#define SQLITE_DBSTATUS_DEFERRED_FKS 10 8213#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 8214#define SQLITE_DBSTATUS_CACHE_SPILL 12 8215#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 8216 8217 8218/* 8219** CAPI3REF: Prepared Statement Status 8220** METHOD: sqlite3_stmt 8221** 8222** ^(Each prepared statement maintains various 8223** [SQLITE_STMTSTATUS counters] that measure the number 8224** of times it has performed specific operations.)^ These counters can 8225** be used to monitor the performance characteristics of the prepared 8226** statements. For example, if the number of table steps greatly exceeds 8227** the number of table searches or result rows, that would tend to indicate 8228** that the prepared statement is using a full table scan rather than 8229** an index. 8230** 8231** ^(This interface is used to retrieve and reset counter values from 8232** a [prepared statement]. The first argument is the prepared statement 8233** object to be interrogated. The second argument 8234** is an integer code for a specific [SQLITE_STMTSTATUS counter] 8235** to be interrogated.)^ 8236** ^The current value of the requested counter is returned. 8237** ^If the resetFlg is true, then the counter is reset to zero after this 8238** interface call returns. 8239** 8240** See also: [sqlite3_status()] and [sqlite3_db_status()]. 8241*/ 8242int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 8243 8244/* 8245** CAPI3REF: Status Parameters for prepared statements 8246** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 8247** 8248** These preprocessor macros define integer codes that name counter 8249** values associated with the [sqlite3_stmt_status()] interface. 8250** The meanings of the various counters are as follows: 8251** 8252** <dl> 8253** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 8254** <dd>^This is the number of times that SQLite has stepped forward in 8255** a table as part of a full table scan. Large numbers for this counter 8256** may indicate opportunities for performance improvement through 8257** careful use of indices.</dd> 8258** 8259** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 8260** <dd>^This is the number of sort operations that have occurred. 8261** A non-zero value in this counter may indicate an opportunity to 8262** improvement performance through careful use of indices.</dd> 8263** 8264** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 8265** <dd>^This is the number of rows inserted into transient indices that 8266** were created automatically in order to help joins run faster. 8267** A non-zero value in this counter may indicate an opportunity to 8268** improvement performance by adding permanent indices that do not 8269** need to be reinitialized each time the statement is run.</dd> 8270** 8271** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 8272** <dd>^This is the number of virtual machine operations executed 8273** by the prepared statement if that number is less than or equal 8274** to 2147483647. The number of virtual machine operations can be 8275** used as a proxy for the total work done by the prepared statement. 8276** If the number of virtual machine operations exceeds 2147483647 8277** then the value returned by this statement status code is undefined. 8278** 8279** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 8280** <dd>^This is the number of times that the prepare statement has been 8281** automatically regenerated due to schema changes or changes to 8282** [bound parameters] that might affect the query plan. 8283** 8284** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 8285** <dd>^This is the number of times that the prepared statement has 8286** been run. A single "run" for the purposes of this counter is one 8287** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 8288** The counter is incremented on the first [sqlite3_step()] call of each 8289** cycle. 8290** 8291** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 8292** <dd>^This is the approximate number of bytes of heap memory 8293** used to store the prepared statement. ^This value is not actually 8294** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 8295** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 8296** </dd> 8297** </dl> 8298*/ 8299#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 8300#define SQLITE_STMTSTATUS_SORT 2 8301#define SQLITE_STMTSTATUS_AUTOINDEX 3 8302#define SQLITE_STMTSTATUS_VM_STEP 4 8303#define SQLITE_STMTSTATUS_REPREPARE 5 8304#define SQLITE_STMTSTATUS_RUN 6 8305#define SQLITE_STMTSTATUS_MEMUSED 99 8306 8307/* 8308** CAPI3REF: Custom Page Cache Object 8309** 8310** The sqlite3_pcache type is opaque. It is implemented by 8311** the pluggable module. The SQLite core has no knowledge of 8312** its size or internal structure and never deals with the 8313** sqlite3_pcache object except by holding and passing pointers 8314** to the object. 8315** 8316** See [sqlite3_pcache_methods2] for additional information. 8317*/ 8318typedef struct sqlite3_pcache sqlite3_pcache; 8319 8320/* 8321** CAPI3REF: Custom Page Cache Object 8322** 8323** The sqlite3_pcache_page object represents a single page in the 8324** page cache. The page cache will allocate instances of this 8325** object. Various methods of the page cache use pointers to instances 8326** of this object as parameters or as their return value. 8327** 8328** See [sqlite3_pcache_methods2] for additional information. 8329*/ 8330typedef struct sqlite3_pcache_page sqlite3_pcache_page; 8331struct sqlite3_pcache_page { 8332 void *pBuf; /* The content of the page */ 8333 void *pExtra; /* Extra information associated with the page */ 8334}; 8335 8336/* 8337** CAPI3REF: Application Defined Page Cache. 8338** KEYWORDS: {page cache} 8339** 8340** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 8341** register an alternative page cache implementation by passing in an 8342** instance of the sqlite3_pcache_methods2 structure.)^ 8343** In many applications, most of the heap memory allocated by 8344** SQLite is used for the page cache. 8345** By implementing a 8346** custom page cache using this API, an application can better control 8347** the amount of memory consumed by SQLite, the way in which 8348** that memory is allocated and released, and the policies used to 8349** determine exactly which parts of a database file are cached and for 8350** how long. 8351** 8352** The alternative page cache mechanism is an 8353** extreme measure that is only needed by the most demanding applications. 8354** The built-in page cache is recommended for most uses. 8355** 8356** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 8357** internal buffer by SQLite within the call to [sqlite3_config]. Hence 8358** the application may discard the parameter after the call to 8359** [sqlite3_config()] returns.)^ 8360** 8361** [[the xInit() page cache method]] 8362** ^(The xInit() method is called once for each effective 8363** call to [sqlite3_initialize()])^ 8364** (usually only once during the lifetime of the process). ^(The xInit() 8365** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 8366** The intent of the xInit() method is to set up global data structures 8367** required by the custom page cache implementation. 8368** ^(If the xInit() method is NULL, then the 8369** built-in default page cache is used instead of the application defined 8370** page cache.)^ 8371** 8372** [[the xShutdown() page cache method]] 8373** ^The xShutdown() method is called by [sqlite3_shutdown()]. 8374** It can be used to clean up 8375** any outstanding resources before process shutdown, if required. 8376** ^The xShutdown() method may be NULL. 8377** 8378** ^SQLite automatically serializes calls to the xInit method, 8379** so the xInit method need not be threadsafe. ^The 8380** xShutdown method is only called from [sqlite3_shutdown()] so it does 8381** not need to be threadsafe either. All other methods must be threadsafe 8382** in multithreaded applications. 8383** 8384** ^SQLite will never invoke xInit() more than once without an intervening 8385** call to xShutdown(). 8386** 8387** [[the xCreate() page cache methods]] 8388** ^SQLite invokes the xCreate() method to construct a new cache instance. 8389** SQLite will typically create one cache instance for each open database file, 8390** though this is not guaranteed. ^The 8391** first parameter, szPage, is the size in bytes of the pages that must 8392** be allocated by the cache. ^szPage will always a power of two. ^The 8393** second parameter szExtra is a number of bytes of extra storage 8394** associated with each page cache entry. ^The szExtra parameter will 8395** a number less than 250. SQLite will use the 8396** extra szExtra bytes on each page to store metadata about the underlying 8397** database page on disk. The value passed into szExtra depends 8398** on the SQLite version, the target platform, and how SQLite was compiled. 8399** ^The third argument to xCreate(), bPurgeable, is true if the cache being 8400** created will be used to cache database pages of a file stored on disk, or 8401** false if it is used for an in-memory database. The cache implementation 8402** does not have to do anything special based with the value of bPurgeable; 8403** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 8404** never invoke xUnpin() except to deliberately delete a page. 8405** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 8406** false will always have the "discard" flag set to true. 8407** ^Hence, a cache created with bPurgeable false will 8408** never contain any unpinned pages. 8409** 8410** [[the xCachesize() page cache method]] 8411** ^(The xCachesize() method may be called at any time by SQLite to set the 8412** suggested maximum cache-size (number of pages stored by) the cache 8413** instance passed as the first argument. This is the value configured using 8414** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 8415** parameter, the implementation is not required to do anything with this 8416** value; it is advisory only. 8417** 8418** [[the xPagecount() page cache methods]] 8419** The xPagecount() method must return the number of pages currently 8420** stored in the cache, both pinned and unpinned. 8421** 8422** [[the xFetch() page cache methods]] 8423** The xFetch() method locates a page in the cache and returns a pointer to 8424** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 8425** The pBuf element of the returned sqlite3_pcache_page object will be a 8426** pointer to a buffer of szPage bytes used to store the content of a 8427** single database page. The pExtra element of sqlite3_pcache_page will be 8428** a pointer to the szExtra bytes of extra storage that SQLite has requested 8429** for each entry in the page cache. 8430** 8431** The page to be fetched is determined by the key. ^The minimum key value 8432** is 1. After it has been retrieved using xFetch, the page is considered 8433** to be "pinned". 8434** 8435** If the requested page is already in the page cache, then the page cache 8436** implementation must return a pointer to the page buffer with its content 8437** intact. If the requested page is not already in the cache, then the 8438** cache implementation should use the value of the createFlag 8439** parameter to help it determined what action to take: 8440** 8441** <table border=1 width=85% align=center> 8442** <tr><th> createFlag <th> Behavior when page is not already in cache 8443** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 8444** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 8445** Otherwise return NULL. 8446** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 8447** NULL if allocating a new page is effectively impossible. 8448** </table> 8449** 8450** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 8451** will only use a createFlag of 2 after a prior call with a createFlag of 1 8452** failed.)^ In between the xFetch() calls, SQLite may 8453** attempt to unpin one or more cache pages by spilling the content of 8454** pinned pages to disk and synching the operating system disk cache. 8455** 8456** [[the xUnpin() page cache method]] 8457** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 8458** as its second argument. If the third parameter, discard, is non-zero, 8459** then the page must be evicted from the cache. 8460** ^If the discard parameter is 8461** zero, then the page may be discarded or retained at the discretion of 8462** page cache implementation. ^The page cache implementation 8463** may choose to evict unpinned pages at any time. 8464** 8465** The cache must not perform any reference counting. A single 8466** call to xUnpin() unpins the page regardless of the number of prior calls 8467** to xFetch(). 8468** 8469** [[the xRekey() page cache methods]] 8470** The xRekey() method is used to change the key value associated with the 8471** page passed as the second argument. If the cache 8472** previously contains an entry associated with newKey, it must be 8473** discarded. ^Any prior cache entry associated with newKey is guaranteed not 8474** to be pinned. 8475** 8476** When SQLite calls the xTruncate() method, the cache must discard all 8477** existing cache entries with page numbers (keys) greater than or equal 8478** to the value of the iLimit parameter passed to xTruncate(). If any 8479** of these pages are pinned, they are implicitly unpinned, meaning that 8480** they can be safely discarded. 8481** 8482** [[the xDestroy() page cache method]] 8483** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 8484** All resources associated with the specified cache should be freed. ^After 8485** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 8486** handle invalid, and will not use it with any other sqlite3_pcache_methods2 8487** functions. 8488** 8489** [[the xShrink() page cache method]] 8490** ^SQLite invokes the xShrink() method when it wants the page cache to 8491** free up as much of heap memory as possible. The page cache implementation 8492** is not obligated to free any memory, but well-behaved implementations should 8493** do their best. 8494*/ 8495typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 8496struct sqlite3_pcache_methods2 { 8497 int iVersion; 8498 void *pArg; 8499 int (*xInit)(void*); 8500 void (*xShutdown)(void*); 8501 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 8502 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8503 int (*xPagecount)(sqlite3_pcache*); 8504 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8505 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 8506 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 8507 unsigned oldKey, unsigned newKey); 8508 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8509 void (*xDestroy)(sqlite3_pcache*); 8510 void (*xShrink)(sqlite3_pcache*); 8511}; 8512 8513/* 8514** This is the obsolete pcache_methods object that has now been replaced 8515** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 8516** retained in the header file for backwards compatibility only. 8517*/ 8518typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 8519struct sqlite3_pcache_methods { 8520 void *pArg; 8521 int (*xInit)(void*); 8522 void (*xShutdown)(void*); 8523 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 8524 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8525 int (*xPagecount)(sqlite3_pcache*); 8526 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8527 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 8528 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 8529 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8530 void (*xDestroy)(sqlite3_pcache*); 8531}; 8532 8533 8534/* 8535** CAPI3REF: Online Backup Object 8536** 8537** The sqlite3_backup object records state information about an ongoing 8538** online backup operation. ^The sqlite3_backup object is created by 8539** a call to [sqlite3_backup_init()] and is destroyed by a call to 8540** [sqlite3_backup_finish()]. 8541** 8542** See Also: [Using the SQLite Online Backup API] 8543*/ 8544typedef struct sqlite3_backup sqlite3_backup; 8545 8546/* 8547** CAPI3REF: Online Backup API. 8548** 8549** The backup API copies the content of one database into another. 8550** It is useful either for creating backups of databases or 8551** for copying in-memory databases to or from persistent files. 8552** 8553** See Also: [Using the SQLite Online Backup API] 8554** 8555** ^SQLite holds a write transaction open on the destination database file 8556** for the duration of the backup operation. 8557** ^The source database is read-locked only while it is being read; 8558** it is not locked continuously for the entire backup operation. 8559** ^Thus, the backup may be performed on a live source database without 8560** preventing other database connections from 8561** reading or writing to the source database while the backup is underway. 8562** 8563** ^(To perform a backup operation: 8564** <ol> 8565** <li><b>sqlite3_backup_init()</b> is called once to initialize the 8566** backup, 8567** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 8568** the data between the two databases, and finally 8569** <li><b>sqlite3_backup_finish()</b> is called to release all resources 8570** associated with the backup operation. 8571** </ol>)^ 8572** There should be exactly one call to sqlite3_backup_finish() for each 8573** successful call to sqlite3_backup_init(). 8574** 8575** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 8576** 8577** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 8578** [database connection] associated with the destination database 8579** and the database name, respectively. 8580** ^The database name is "main" for the main database, "temp" for the 8581** temporary database, or the name specified after the AS keyword in 8582** an [ATTACH] statement for an attached database. 8583** ^The S and M arguments passed to 8584** sqlite3_backup_init(D,N,S,M) identify the [database connection] 8585** and database name of the source database, respectively. 8586** ^The source and destination [database connections] (parameters S and D) 8587** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 8588** an error. 8589** 8590** ^A call to sqlite3_backup_init() will fail, returning NULL, if 8591** there is already a read or read-write transaction open on the 8592** destination database. 8593** 8594** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 8595** returned and an error code and error message are stored in the 8596** destination [database connection] D. 8597** ^The error code and message for the failed call to sqlite3_backup_init() 8598** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 8599** [sqlite3_errmsg16()] functions. 8600** ^A successful call to sqlite3_backup_init() returns a pointer to an 8601** [sqlite3_backup] object. 8602** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 8603** sqlite3_backup_finish() functions to perform the specified backup 8604** operation. 8605** 8606** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 8607** 8608** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 8609** the source and destination databases specified by [sqlite3_backup] object B. 8610** ^If N is negative, all remaining source pages are copied. 8611** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 8612** are still more pages to be copied, then the function returns [SQLITE_OK]. 8613** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 8614** from source to destination, then it returns [SQLITE_DONE]. 8615** ^If an error occurs while running sqlite3_backup_step(B,N), 8616** then an [error code] is returned. ^As well as [SQLITE_OK] and 8617** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 8618** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 8619** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 8620** 8621** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 8622** <ol> 8623** <li> the destination database was opened read-only, or 8624** <li> the destination database is using write-ahead-log journaling 8625** and the destination and source page sizes differ, or 8626** <li> the destination database is an in-memory database and the 8627** destination and source page sizes differ. 8628** </ol>)^ 8629** 8630** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 8631** the [sqlite3_busy_handler | busy-handler function] 8632** is invoked (if one is specified). ^If the 8633** busy-handler returns non-zero before the lock is available, then 8634** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 8635** sqlite3_backup_step() can be retried later. ^If the source 8636** [database connection] 8637** is being used to write to the source database when sqlite3_backup_step() 8638** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 8639** case the call to sqlite3_backup_step() can be retried later on. ^(If 8640** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 8641** [SQLITE_READONLY] is returned, then 8642** there is no point in retrying the call to sqlite3_backup_step(). These 8643** errors are considered fatal.)^ The application must accept 8644** that the backup operation has failed and pass the backup operation handle 8645** to the sqlite3_backup_finish() to release associated resources. 8646** 8647** ^The first call to sqlite3_backup_step() obtains an exclusive lock 8648** on the destination file. ^The exclusive lock is not released until either 8649** sqlite3_backup_finish() is called or the backup operation is complete 8650** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 8651** sqlite3_backup_step() obtains a [shared lock] on the source database that 8652** lasts for the duration of the sqlite3_backup_step() call. 8653** ^Because the source database is not locked between calls to 8654** sqlite3_backup_step(), the source database may be modified mid-way 8655** through the backup process. ^If the source database is modified by an 8656** external process or via a database connection other than the one being 8657** used by the backup operation, then the backup will be automatically 8658** restarted by the next call to sqlite3_backup_step(). ^If the source 8659** database is modified by the using the same database connection as is used 8660** by the backup operation, then the backup database is automatically 8661** updated at the same time. 8662** 8663** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 8664** 8665** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 8666** application wishes to abandon the backup operation, the application 8667** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 8668** ^The sqlite3_backup_finish() interfaces releases all 8669** resources associated with the [sqlite3_backup] object. 8670** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 8671** active write-transaction on the destination database is rolled back. 8672** The [sqlite3_backup] object is invalid 8673** and may not be used following a call to sqlite3_backup_finish(). 8674** 8675** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 8676** sqlite3_backup_step() errors occurred, regardless or whether or not 8677** sqlite3_backup_step() completed. 8678** ^If an out-of-memory condition or IO error occurred during any prior 8679** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 8680** sqlite3_backup_finish() returns the corresponding [error code]. 8681** 8682** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 8683** is not a permanent error and does not affect the return value of 8684** sqlite3_backup_finish(). 8685** 8686** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 8687** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 8688** 8689** ^The sqlite3_backup_remaining() routine returns the number of pages still 8690** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 8691** ^The sqlite3_backup_pagecount() routine returns the total number of pages 8692** in the source database at the conclusion of the most recent 8693** sqlite3_backup_step(). 8694** ^(The values returned by these functions are only updated by 8695** sqlite3_backup_step(). If the source database is modified in a way that 8696** changes the size of the source database or the number of pages remaining, 8697** those changes are not reflected in the output of sqlite3_backup_pagecount() 8698** and sqlite3_backup_remaining() until after the next 8699** sqlite3_backup_step().)^ 8700** 8701** <b>Concurrent Usage of Database Handles</b> 8702** 8703** ^The source [database connection] may be used by the application for other 8704** purposes while a backup operation is underway or being initialized. 8705** ^If SQLite is compiled and configured to support threadsafe database 8706** connections, then the source database connection may be used concurrently 8707** from within other threads. 8708** 8709** However, the application must guarantee that the destination 8710** [database connection] is not passed to any other API (by any thread) after 8711** sqlite3_backup_init() is called and before the corresponding call to 8712** sqlite3_backup_finish(). SQLite does not currently check to see 8713** if the application incorrectly accesses the destination [database connection] 8714** and so no error code is reported, but the operations may malfunction 8715** nevertheless. Use of the destination database connection while a 8716** backup is in progress might also also cause a mutex deadlock. 8717** 8718** If running in [shared cache mode], the application must 8719** guarantee that the shared cache used by the destination database 8720** is not accessed while the backup is running. In practice this means 8721** that the application must guarantee that the disk file being 8722** backed up to is not accessed by any connection within the process, 8723** not just the specific connection that was passed to sqlite3_backup_init(). 8724** 8725** The [sqlite3_backup] object itself is partially threadsafe. Multiple 8726** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 8727** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 8728** APIs are not strictly speaking threadsafe. If they are invoked at the 8729** same time as another thread is invoking sqlite3_backup_step() it is 8730** possible that they return invalid values. 8731*/ 8732sqlite3_backup *sqlite3_backup_init( 8733 sqlite3 *pDest, /* Destination database handle */ 8734 const char *zDestName, /* Destination database name */ 8735 sqlite3 *pSource, /* Source database handle */ 8736 const char *zSourceName /* Source database name */ 8737); 8738int sqlite3_backup_step(sqlite3_backup *p, int nPage); 8739int sqlite3_backup_finish(sqlite3_backup *p); 8740int sqlite3_backup_remaining(sqlite3_backup *p); 8741int sqlite3_backup_pagecount(sqlite3_backup *p); 8742 8743/* 8744** CAPI3REF: Unlock Notification 8745** METHOD: sqlite3 8746** 8747** ^When running in shared-cache mode, a database operation may fail with 8748** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 8749** individual tables within the shared-cache cannot be obtained. See 8750** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 8751** ^This API may be used to register a callback that SQLite will invoke 8752** when the connection currently holding the required lock relinquishes it. 8753** ^This API is only available if the library was compiled with the 8754** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 8755** 8756** See Also: [Using the SQLite Unlock Notification Feature]. 8757** 8758** ^Shared-cache locks are released when a database connection concludes 8759** its current transaction, either by committing it or rolling it back. 8760** 8761** ^When a connection (known as the blocked connection) fails to obtain a 8762** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 8763** identity of the database connection (the blocking connection) that 8764** has locked the required resource is stored internally. ^After an 8765** application receives an SQLITE_LOCKED error, it may call the 8766** sqlite3_unlock_notify() method with the blocked connection handle as 8767** the first argument to register for a callback that will be invoked 8768** when the blocking connections current transaction is concluded. ^The 8769** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 8770** call that concludes the blocking connection's transaction. 8771** 8772** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 8773** there is a chance that the blocking connection will have already 8774** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 8775** If this happens, then the specified callback is invoked immediately, 8776** from within the call to sqlite3_unlock_notify().)^ 8777** 8778** ^If the blocked connection is attempting to obtain a write-lock on a 8779** shared-cache table, and more than one other connection currently holds 8780** a read-lock on the same table, then SQLite arbitrarily selects one of 8781** the other connections to use as the blocking connection. 8782** 8783** ^(There may be at most one unlock-notify callback registered by a 8784** blocked connection. If sqlite3_unlock_notify() is called when the 8785** blocked connection already has a registered unlock-notify callback, 8786** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 8787** called with a NULL pointer as its second argument, then any existing 8788** unlock-notify callback is canceled. ^The blocked connections 8789** unlock-notify callback may also be canceled by closing the blocked 8790** connection using [sqlite3_close()]. 8791** 8792** The unlock-notify callback is not reentrant. If an application invokes 8793** any sqlite3_xxx API functions from within an unlock-notify callback, a 8794** crash or deadlock may be the result. 8795** 8796** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 8797** returns SQLITE_OK. 8798** 8799** <b>Callback Invocation Details</b> 8800** 8801** When an unlock-notify callback is registered, the application provides a 8802** single void* pointer that is passed to the callback when it is invoked. 8803** However, the signature of the callback function allows SQLite to pass 8804** it an array of void* context pointers. The first argument passed to 8805** an unlock-notify callback is a pointer to an array of void* pointers, 8806** and the second is the number of entries in the array. 8807** 8808** When a blocking connection's transaction is concluded, there may be 8809** more than one blocked connection that has registered for an unlock-notify 8810** callback. ^If two or more such blocked connections have specified the 8811** same callback function, then instead of invoking the callback function 8812** multiple times, it is invoked once with the set of void* context pointers 8813** specified by the blocked connections bundled together into an array. 8814** This gives the application an opportunity to prioritize any actions 8815** related to the set of unblocked database connections. 8816** 8817** <b>Deadlock Detection</b> 8818** 8819** Assuming that after registering for an unlock-notify callback a 8820** database waits for the callback to be issued before taking any further 8821** action (a reasonable assumption), then using this API may cause the 8822** application to deadlock. For example, if connection X is waiting for 8823** connection Y's transaction to be concluded, and similarly connection 8824** Y is waiting on connection X's transaction, then neither connection 8825** will proceed and the system may remain deadlocked indefinitely. 8826** 8827** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 8828** detection. ^If a given call to sqlite3_unlock_notify() would put the 8829** system in a deadlocked state, then SQLITE_LOCKED is returned and no 8830** unlock-notify callback is registered. The system is said to be in 8831** a deadlocked state if connection A has registered for an unlock-notify 8832** callback on the conclusion of connection B's transaction, and connection 8833** B has itself registered for an unlock-notify callback when connection 8834** A's transaction is concluded. ^Indirect deadlock is also detected, so 8835** the system is also considered to be deadlocked if connection B has 8836** registered for an unlock-notify callback on the conclusion of connection 8837** C's transaction, where connection C is waiting on connection A. ^Any 8838** number of levels of indirection are allowed. 8839** 8840** <b>The "DROP TABLE" Exception</b> 8841** 8842** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 8843** always appropriate to call sqlite3_unlock_notify(). There is however, 8844** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 8845** SQLite checks if there are any currently executing SELECT statements 8846** that belong to the same connection. If there are, SQLITE_LOCKED is 8847** returned. In this case there is no "blocking connection", so invoking 8848** sqlite3_unlock_notify() results in the unlock-notify callback being 8849** invoked immediately. If the application then re-attempts the "DROP TABLE" 8850** or "DROP INDEX" query, an infinite loop might be the result. 8851** 8852** One way around this problem is to check the extended error code returned 8853** by an sqlite3_step() call. ^(If there is a blocking connection, then the 8854** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 8855** the special "DROP TABLE/INDEX" case, the extended error code is just 8856** SQLITE_LOCKED.)^ 8857*/ 8858int sqlite3_unlock_notify( 8859 sqlite3 *pBlocked, /* Waiting connection */ 8860 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 8861 void *pNotifyArg /* Argument to pass to xNotify */ 8862); 8863 8864 8865/* 8866** CAPI3REF: String Comparison 8867** 8868** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 8869** and extensions to compare the contents of two buffers containing UTF-8 8870** strings in a case-independent fashion, using the same definition of "case 8871** independence" that SQLite uses internally when comparing identifiers. 8872*/ 8873int sqlite3_stricmp(const char *, const char *); 8874int sqlite3_strnicmp(const char *, const char *, int); 8875 8876/* 8877** CAPI3REF: String Globbing 8878* 8879** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 8880** string X matches the [GLOB] pattern P. 8881** ^The definition of [GLOB] pattern matching used in 8882** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 8883** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 8884** is case sensitive. 8885** 8886** Note that this routine returns zero on a match and non-zero if the strings 8887** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8888** 8889** See also: [sqlite3_strlike()]. 8890*/ 8891int sqlite3_strglob(const char *zGlob, const char *zStr); 8892 8893/* 8894** CAPI3REF: String LIKE Matching 8895* 8896** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 8897** string X matches the [LIKE] pattern P with escape character E. 8898** ^The definition of [LIKE] pattern matching used in 8899** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 8900** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 8901** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 8902** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 8903** insensitive - equivalent upper and lower case ASCII characters match 8904** one another. 8905** 8906** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 8907** only ASCII characters are case folded. 8908** 8909** Note that this routine returns zero on a match and non-zero if the strings 8910** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8911** 8912** See also: [sqlite3_strglob()]. 8913*/ 8914int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8915 8916/* 8917** CAPI3REF: Error Logging Interface 8918** 8919** ^The [sqlite3_log()] interface writes a message into the [error log] 8920** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8921** ^If logging is enabled, the zFormat string and subsequent arguments are 8922** used with [sqlite3_snprintf()] to generate the final output string. 8923** 8924** The sqlite3_log() interface is intended for use by extensions such as 8925** virtual tables, collating functions, and SQL functions. While there is 8926** nothing to prevent an application from calling sqlite3_log(), doing so 8927** is considered bad form. 8928** 8929** The zFormat string must not be NULL. 8930** 8931** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8932** will not use dynamically allocated memory. The log message is stored in 8933** a fixed-length buffer on the stack. If the log message is longer than 8934** a few hundred characters, it will be truncated to the length of the 8935** buffer. 8936*/ 8937void sqlite3_log(int iErrCode, const char *zFormat, ...); 8938 8939/* 8940** CAPI3REF: Write-Ahead Log Commit Hook 8941** METHOD: sqlite3 8942** 8943** ^The [sqlite3_wal_hook()] function is used to register a callback that 8944** is invoked each time data is committed to a database in wal mode. 8945** 8946** ^(The callback is invoked by SQLite after the commit has taken place and 8947** the associated write-lock on the database released)^, so the implementation 8948** may read, write or [checkpoint] the database as required. 8949** 8950** ^The first parameter passed to the callback function when it is invoked 8951** is a copy of the third parameter passed to sqlite3_wal_hook() when 8952** registering the callback. ^The second is a copy of the database handle. 8953** ^The third parameter is the name of the database that was written to - 8954** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8955** is the number of pages currently in the write-ahead log file, 8956** including those that were just committed. 8957** 8958** The callback function should normally return [SQLITE_OK]. ^If an error 8959** code is returned, that error will propagate back up through the 8960** SQLite code base to cause the statement that provoked the callback 8961** to report an error, though the commit will have still occurred. If the 8962** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8963** that does not correspond to any valid SQLite error code, the results 8964** are undefined. 8965** 8966** A single database handle may have at most a single write-ahead log callback 8967** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8968** previously registered write-ahead log callback. ^Note that the 8969** [sqlite3_wal_autocheckpoint()] interface and the 8970** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8971** overwrite any prior [sqlite3_wal_hook()] settings. 8972*/ 8973void *sqlite3_wal_hook( 8974 sqlite3*, 8975 int(*)(void *,sqlite3*,const char*,int), 8976 void* 8977); 8978 8979/* 8980** CAPI3REF: Configure an auto-checkpoint 8981** METHOD: sqlite3 8982** 8983** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8984** [sqlite3_wal_hook()] that causes any database on [database connection] D 8985** to automatically [checkpoint] 8986** after committing a transaction if there are N or 8987** more frames in the [write-ahead log] file. ^Passing zero or 8988** a negative value as the nFrame parameter disables automatic 8989** checkpoints entirely. 8990** 8991** ^The callback registered by this function replaces any existing callback 8992** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8993** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8994** configured by this function. 8995** 8996** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8997** from SQL. 8998** 8999** ^Checkpoints initiated by this mechanism are 9000** [sqlite3_wal_checkpoint_v2|PASSIVE]. 9001** 9002** ^Every new [database connection] defaults to having the auto-checkpoint 9003** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 9004** pages. The use of this interface 9005** is only necessary if the default setting is found to be suboptimal 9006** for a particular application. 9007*/ 9008int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 9009 9010/* 9011** CAPI3REF: Checkpoint a database 9012** METHOD: sqlite3 9013** 9014** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 9015** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 9016** 9017** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 9018** [write-ahead log] for database X on [database connection] D to be 9019** transferred into the database file and for the write-ahead log to 9020** be reset. See the [checkpointing] documentation for addition 9021** information. 9022** 9023** This interface used to be the only way to cause a checkpoint to 9024** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 9025** interface was added. This interface is retained for backwards 9026** compatibility and as a convenience for applications that need to manually 9027** start a callback but which do not need the full power (and corresponding 9028** complication) of [sqlite3_wal_checkpoint_v2()]. 9029*/ 9030int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 9031 9032/* 9033** CAPI3REF: Checkpoint a database 9034** METHOD: sqlite3 9035** 9036** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 9037** operation on database X of [database connection] D in mode M. Status 9038** information is written back into integers pointed to by L and C.)^ 9039** ^(The M parameter must be a valid [checkpoint mode]:)^ 9040** 9041** <dl> 9042** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 9043** ^Checkpoint as many frames as possible without waiting for any database 9044** readers or writers to finish, then sync the database file if all frames 9045** in the log were checkpointed. ^The [busy-handler callback] 9046** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 9047** ^On the other hand, passive mode might leave the checkpoint unfinished 9048** if there are concurrent readers or writers. 9049** 9050** <dt>SQLITE_CHECKPOINT_FULL<dd> 9051** ^This mode blocks (it invokes the 9052** [sqlite3_busy_handler|busy-handler callback]) until there is no 9053** database writer and all readers are reading from the most recent database 9054** snapshot. ^It then checkpoints all frames in the log file and syncs the 9055** database file. ^This mode blocks new database writers while it is pending, 9056** but new database readers are allowed to continue unimpeded. 9057** 9058** <dt>SQLITE_CHECKPOINT_RESTART<dd> 9059** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 9060** that after checkpointing the log file it blocks (calls the 9061** [busy-handler callback]) 9062** until all readers are reading from the database file only. ^This ensures 9063** that the next writer will restart the log file from the beginning. 9064** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 9065** database writer attempts while it is pending, but does not impede readers. 9066** 9067** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 9068** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 9069** addition that it also truncates the log file to zero bytes just prior 9070** to a successful return. 9071** </dl> 9072** 9073** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 9074** the log file or to -1 if the checkpoint could not run because 9075** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 9076** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 9077** log file (including any that were already checkpointed before the function 9078** was called) or to -1 if the checkpoint could not run due to an error or 9079** because the database is not in WAL mode. ^Note that upon successful 9080** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 9081** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 9082** 9083** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 9084** any other process is running a checkpoint operation at the same time, the 9085** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 9086** busy-handler configured, it will not be invoked in this case. 9087** 9088** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 9089** exclusive "writer" lock on the database file. ^If the writer lock cannot be 9090** obtained immediately, and a busy-handler is configured, it is invoked and 9091** the writer lock retried until either the busy-handler returns 0 or the lock 9092** is successfully obtained. ^The busy-handler is also invoked while waiting for 9093** database readers as described above. ^If the busy-handler returns 0 before 9094** the writer lock is obtained or while waiting for database readers, the 9095** checkpoint operation proceeds from that point in the same way as 9096** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 9097** without blocking any further. ^SQLITE_BUSY is returned in this case. 9098** 9099** ^If parameter zDb is NULL or points to a zero length string, then the 9100** specified operation is attempted on all WAL databases [attached] to 9101** [database connection] db. In this case the 9102** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 9103** an SQLITE_BUSY error is encountered when processing one or more of the 9104** attached WAL databases, the operation is still attempted on any remaining 9105** attached databases and SQLITE_BUSY is returned at the end. ^If any other 9106** error occurs while processing an attached database, processing is abandoned 9107** and the error code is returned to the caller immediately. ^If no error 9108** (SQLITE_BUSY or otherwise) is encountered while processing the attached 9109** databases, SQLITE_OK is returned. 9110** 9111** ^If database zDb is the name of an attached database that is not in WAL 9112** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 9113** zDb is not NULL (or a zero length string) and is not the name of any 9114** attached database, SQLITE_ERROR is returned to the caller. 9115** 9116** ^Unless it returns SQLITE_MISUSE, 9117** the sqlite3_wal_checkpoint_v2() interface 9118** sets the error information that is queried by 9119** [sqlite3_errcode()] and [sqlite3_errmsg()]. 9120** 9121** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 9122** from SQL. 9123*/ 9124int sqlite3_wal_checkpoint_v2( 9125 sqlite3 *db, /* Database handle */ 9126 const char *zDb, /* Name of attached database (or NULL) */ 9127 int eMode, /* SQLITE_CHECKPOINT_* value */ 9128 int *pnLog, /* OUT: Size of WAL log in frames */ 9129 int *pnCkpt /* OUT: Total number of frames checkpointed */ 9130); 9131 9132/* 9133** CAPI3REF: Checkpoint Mode Values 9134** KEYWORDS: {checkpoint mode} 9135** 9136** These constants define all valid values for the "checkpoint mode" passed 9137** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 9138** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 9139** meaning of each of these checkpoint modes. 9140*/ 9141#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 9142#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 9143#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 9144#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 9145 9146/* 9147** CAPI3REF: Virtual Table Interface Configuration 9148** 9149** This function may be called by either the [xConnect] or [xCreate] method 9150** of a [virtual table] implementation to configure 9151** various facets of the virtual table interface. 9152** 9153** If this interface is invoked outside the context of an xConnect or 9154** xCreate virtual table method then the behavior is undefined. 9155** 9156** In the call sqlite3_vtab_config(D,C,...) the D parameter is the 9157** [database connection] in which the virtual table is being created and 9158** which is passed in as the first argument to the [xConnect] or [xCreate] 9159** method that is invoking sqlite3_vtab_config(). The C parameter is one 9160** of the [virtual table configuration options]. The presence and meaning 9161** of parameters after C depend on which [virtual table configuration option] 9162** is used. 9163*/ 9164int sqlite3_vtab_config(sqlite3*, int op, ...); 9165 9166/* 9167** CAPI3REF: Virtual Table Configuration Options 9168** KEYWORDS: {virtual table configuration options} 9169** KEYWORDS: {virtual table configuration option} 9170** 9171** These macros define the various options to the 9172** [sqlite3_vtab_config()] interface that [virtual table] implementations 9173** can use to customize and optimize their behavior. 9174** 9175** <dl> 9176** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]] 9177** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt> 9178** <dd>Calls of the form 9179** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 9180** where X is an integer. If X is zero, then the [virtual table] whose 9181** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 9182** support constraints. In this configuration (which is the default) if 9183** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 9184** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 9185** specified as part of the users SQL statement, regardless of the actual 9186** ON CONFLICT mode specified. 9187** 9188** If X is non-zero, then the virtual table implementation guarantees 9189** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 9190** any modifications to internal or persistent data structures have been made. 9191** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 9192** is able to roll back a statement or database transaction, and abandon 9193** or continue processing the current SQL statement as appropriate. 9194** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 9195** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 9196** had been ABORT. 9197** 9198** Virtual table implementations that are required to handle OR REPLACE 9199** must do so within the [xUpdate] method. If a call to the 9200** [sqlite3_vtab_on_conflict()] function indicates that the current ON 9201** CONFLICT policy is REPLACE, the virtual table implementation should 9202** silently replace the appropriate rows within the xUpdate callback and 9203** return SQLITE_OK. Or, if this is not possible, it may return 9204** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 9205** constraint handling. 9206** </dd> 9207** 9208** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt> 9209** <dd>Calls of the form 9210** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the 9211** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9212** prohibits that virtual table from being used from within triggers and 9213** views. 9214** </dd> 9215** 9216** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt> 9217** <dd>Calls of the form 9218** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the 9219** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9220** identify that virtual table as being safe to use from within triggers 9221** and views. Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the 9222** virtual table can do no serious harm even if it is controlled by a 9223** malicious hacker. Developers should avoid setting the SQLITE_VTAB_INNOCUOUS 9224** flag unless absolutely necessary. 9225** </dd> 9226** </dl> 9227*/ 9228#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 9229#define SQLITE_VTAB_INNOCUOUS 2 9230#define SQLITE_VTAB_DIRECTONLY 3 9231 9232/* 9233** CAPI3REF: Determine The Virtual Table Conflict Policy 9234** 9235** This function may only be called from within a call to the [xUpdate] method 9236** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 9237** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 9238** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 9239** of the SQL statement that triggered the call to the [xUpdate] method of the 9240** [virtual table]. 9241*/ 9242int sqlite3_vtab_on_conflict(sqlite3 *); 9243 9244/* 9245** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 9246** 9247** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 9248** method of a [virtual table], then it might return true if the 9249** column is being fetched as part of an UPDATE operation during which the 9250** column value will not change. The virtual table implementation can use 9251** this hint as permission to substitute a return value that is less 9252** expensive to compute and that the corresponding 9253** [xUpdate] method understands as a "no-change" value. 9254** 9255** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 9256** the column is not changed by the UPDATE statement, then the xColumn 9257** method can optionally return without setting a result, without calling 9258** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 9259** In that case, [sqlite3_value_nochange(X)] will return true for the 9260** same column in the [xUpdate] method. 9261** 9262** The sqlite3_vtab_nochange() routine is an optimization. Virtual table 9263** implementations should continue to give a correct answer even if the 9264** sqlite3_vtab_nochange() interface were to always return false. In the 9265** current implementation, the sqlite3_vtab_nochange() interface does always 9266** returns false for the enhanced [UPDATE FROM] statement. 9267*/ 9268int sqlite3_vtab_nochange(sqlite3_context*); 9269 9270/* 9271** CAPI3REF: Determine The Collation For a Virtual Table Constraint 9272** 9273** This function may only be called from within a call to the [xBestIndex] 9274** method of a [virtual table]. 9275** 9276** The first argument must be the sqlite3_index_info object that is the 9277** first parameter to the xBestIndex() method. The second argument must be 9278** an index into the aConstraint[] array belonging to the sqlite3_index_info 9279** structure passed to xBestIndex. This function returns a pointer to a buffer 9280** containing the name of the collation sequence for the corresponding 9281** constraint. 9282*/ 9283SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 9284 9285/* 9286** CAPI3REF: Conflict resolution modes 9287** KEYWORDS: {conflict resolution mode} 9288** 9289** These constants are returned by [sqlite3_vtab_on_conflict()] to 9290** inform a [virtual table] implementation what the [ON CONFLICT] mode 9291** is for the SQL statement being evaluated. 9292** 9293** Note that the [SQLITE_IGNORE] constant is also used as a potential 9294** return value from the [sqlite3_set_authorizer()] callback and that 9295** [SQLITE_ABORT] is also a [result code]. 9296*/ 9297#define SQLITE_ROLLBACK 1 9298/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 9299#define SQLITE_FAIL 3 9300/* #define SQLITE_ABORT 4 // Also an error code */ 9301#define SQLITE_REPLACE 5 9302 9303/* 9304** CAPI3REF: Prepared Statement Scan Status Opcodes 9305** KEYWORDS: {scanstatus options} 9306** 9307** The following constants can be used for the T parameter to the 9308** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 9309** different metric for sqlite3_stmt_scanstatus() to return. 9310** 9311** When the value returned to V is a string, space to hold that string is 9312** managed by the prepared statement S and will be automatically freed when 9313** S is finalized. 9314** 9315** <dl> 9316** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 9317** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be 9318** set to the total number of times that the X-th loop has run.</dd> 9319** 9320** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 9321** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set 9322** to the total number of rows examined by all iterations of the X-th loop.</dd> 9323** 9324** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 9325** <dd>^The "double" variable pointed to by the V parameter will be set to the 9326** query planner's estimate for the average number of rows output from each 9327** iteration of the X-th loop. If the query planner's estimates was accurate, 9328** then this value will approximate the quotient NVISIT/NLOOP and the 9329** product of this value for all prior loops with the same SELECTID will 9330** be the NLOOP value for the current loop. 9331** 9332** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 9333** <dd>^The "const char *" variable pointed to by the V parameter will be set 9334** to a zero-terminated UTF-8 string containing the name of the index or table 9335** used for the X-th loop. 9336** 9337** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 9338** <dd>^The "const char *" variable pointed to by the V parameter will be set 9339** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 9340** description for the X-th loop. 9341** 9342** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 9343** <dd>^The "int" variable pointed to by the V parameter will be set to the 9344** "select-id" for the X-th loop. The select-id identifies which query or 9345** subquery the loop is part of. The main query has a select-id of zero. 9346** The select-id is the same value as is output in the first column 9347** of an [EXPLAIN QUERY PLAN] query. 9348** </dl> 9349*/ 9350#define SQLITE_SCANSTAT_NLOOP 0 9351#define SQLITE_SCANSTAT_NVISIT 1 9352#define SQLITE_SCANSTAT_EST 2 9353#define SQLITE_SCANSTAT_NAME 3 9354#define SQLITE_SCANSTAT_EXPLAIN 4 9355#define SQLITE_SCANSTAT_SELECTID 5 9356 9357/* 9358** CAPI3REF: Prepared Statement Scan Status 9359** METHOD: sqlite3_stmt 9360** 9361** This interface returns information about the predicted and measured 9362** performance for pStmt. Advanced applications can use this 9363** interface to compare the predicted and the measured performance and 9364** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 9365** 9366** Since this interface is expected to be rarely used, it is only 9367** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 9368** compile-time option. 9369** 9370** The "iScanStatusOp" parameter determines which status information to return. 9371** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 9372** of this interface is undefined. 9373** ^The requested measurement is written into a variable pointed to by 9374** the "pOut" parameter. 9375** Parameter "idx" identifies the specific loop to retrieve statistics for. 9376** Loops are numbered starting from zero. ^If idx is out of range - less than 9377** zero or greater than or equal to the total number of loops used to implement 9378** the statement - a non-zero value is returned and the variable that pOut 9379** points to is unchanged. 9380** 9381** ^Statistics might not be available for all loops in all statements. ^In cases 9382** where there exist loops with no available statistics, this function behaves 9383** as if the loop did not exist - it returns non-zero and leave the variable 9384** that pOut points to unchanged. 9385** 9386** See also: [sqlite3_stmt_scanstatus_reset()] 9387*/ 9388int sqlite3_stmt_scanstatus( 9389 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 9390 int idx, /* Index of loop to report on */ 9391 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 9392 void *pOut /* Result written here */ 9393); 9394 9395/* 9396** CAPI3REF: Zero Scan-Status Counters 9397** METHOD: sqlite3_stmt 9398** 9399** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 9400** 9401** This API is only available if the library is built with pre-processor 9402** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 9403*/ 9404void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 9405 9406/* 9407** CAPI3REF: Flush caches to disk mid-transaction 9408** METHOD: sqlite3 9409** 9410** ^If a write-transaction is open on [database connection] D when the 9411** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 9412** pages in the pager-cache that are not currently in use are written out 9413** to disk. A dirty page may be in use if a database cursor created by an 9414** active SQL statement is reading from it, or if it is page 1 of a database 9415** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 9416** interface flushes caches for all schemas - "main", "temp", and 9417** any [attached] databases. 9418** 9419** ^If this function needs to obtain extra database locks before dirty pages 9420** can be flushed to disk, it does so. ^If those locks cannot be obtained 9421** immediately and there is a busy-handler callback configured, it is invoked 9422** in the usual manner. ^If the required lock still cannot be obtained, then 9423** the database is skipped and an attempt made to flush any dirty pages 9424** belonging to the next (if any) database. ^If any databases are skipped 9425** because locks cannot be obtained, but no other error occurs, this 9426** function returns SQLITE_BUSY. 9427** 9428** ^If any other error occurs while flushing dirty pages to disk (for 9429** example an IO error or out-of-memory condition), then processing is 9430** abandoned and an SQLite [error code] is returned to the caller immediately. 9431** 9432** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 9433** 9434** ^This function does not set the database handle error code or message 9435** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 9436*/ 9437int sqlite3_db_cacheflush(sqlite3*); 9438 9439/* 9440** CAPI3REF: The pre-update hook. 9441** METHOD: sqlite3 9442** 9443** ^These interfaces are only available if SQLite is compiled using the 9444** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 9445** 9446** ^The [sqlite3_preupdate_hook()] interface registers a callback function 9447** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 9448** on a database table. 9449** ^At most one preupdate hook may be registered at a time on a single 9450** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 9451** the previous setting. 9452** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 9453** with a NULL pointer as the second parameter. 9454** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 9455** the first parameter to callbacks. 9456** 9457** ^The preupdate hook only fires for changes to real database tables; the 9458** preupdate hook is not invoked for changes to [virtual tables] or to 9459** system tables like sqlite_sequence or sqlite_stat1. 9460** 9461** ^The second parameter to the preupdate callback is a pointer to 9462** the [database connection] that registered the preupdate hook. 9463** ^The third parameter to the preupdate callback is one of the constants 9464** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 9465** kind of update operation that is about to occur. 9466** ^(The fourth parameter to the preupdate callback is the name of the 9467** database within the database connection that is being modified. This 9468** will be "main" for the main database or "temp" for TEMP tables or 9469** the name given after the AS keyword in the [ATTACH] statement for attached 9470** databases.)^ 9471** ^The fifth parameter to the preupdate callback is the name of the 9472** table that is being modified. 9473** 9474** For an UPDATE or DELETE operation on a [rowid table], the sixth 9475** parameter passed to the preupdate callback is the initial [rowid] of the 9476** row being modified or deleted. For an INSERT operation on a rowid table, 9477** or any operation on a WITHOUT ROWID table, the value of the sixth 9478** parameter is undefined. For an INSERT or UPDATE on a rowid table the 9479** seventh parameter is the final rowid value of the row being inserted 9480** or updated. The value of the seventh parameter passed to the callback 9481** function is not defined for operations on WITHOUT ROWID tables, or for 9482** DELETE operations on rowid tables. 9483** 9484** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 9485** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 9486** provide additional information about a preupdate event. These routines 9487** may only be called from within a preupdate callback. Invoking any of 9488** these routines from outside of a preupdate callback or with a 9489** [database connection] pointer that is different from the one supplied 9490** to the preupdate callback results in undefined and probably undesirable 9491** behavior. 9492** 9493** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 9494** in the row that is being inserted, updated, or deleted. 9495** 9496** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 9497** a [protected sqlite3_value] that contains the value of the Nth column of 9498** the table row before it is updated. The N parameter must be between 0 9499** and one less than the number of columns or the behavior will be 9500** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 9501** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 9502** behavior is undefined. The [sqlite3_value] that P points to 9503** will be destroyed when the preupdate callback returns. 9504** 9505** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 9506** a [protected sqlite3_value] that contains the value of the Nth column of 9507** the table row after it is updated. The N parameter must be between 0 9508** and one less than the number of columns or the behavior will be 9509** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 9510** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 9511** behavior is undefined. The [sqlite3_value] that P points to 9512** will be destroyed when the preupdate callback returns. 9513** 9514** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 9515** callback was invoked as a result of a direct insert, update, or delete 9516** operation; or 1 for inserts, updates, or deletes invoked by top-level 9517** triggers; or 2 for changes resulting from triggers called by top-level 9518** triggers; and so forth. 9519** 9520** See also: [sqlite3_update_hook()] 9521*/ 9522#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 9523void *sqlite3_preupdate_hook( 9524 sqlite3 *db, 9525 void(*xPreUpdate)( 9526 void *pCtx, /* Copy of third arg to preupdate_hook() */ 9527 sqlite3 *db, /* Database handle */ 9528 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 9529 char const *zDb, /* Database name */ 9530 char const *zName, /* Table name */ 9531 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 9532 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 9533 ), 9534 void* 9535); 9536int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 9537int sqlite3_preupdate_count(sqlite3 *); 9538int sqlite3_preupdate_depth(sqlite3 *); 9539int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 9540#endif 9541 9542/* 9543** CAPI3REF: Low-level system error code 9544** METHOD: sqlite3 9545** 9546** ^Attempt to return the underlying operating system error code or error 9547** number that caused the most recent I/O error or failure to open a file. 9548** The return value is OS-dependent. For example, on unix systems, after 9549** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 9550** called to get back the underlying "errno" that caused the problem, such 9551** as ENOSPC, EAUTH, EISDIR, and so forth. 9552*/ 9553int sqlite3_system_errno(sqlite3*); 9554 9555/* 9556** CAPI3REF: Database Snapshot 9557** KEYWORDS: {snapshot} {sqlite3_snapshot} 9558** 9559** An instance of the snapshot object records the state of a [WAL mode] 9560** database for some specific point in history. 9561** 9562** In [WAL mode], multiple [database connections] that are open on the 9563** same database file can each be reading a different historical version 9564** of the database file. When a [database connection] begins a read 9565** transaction, that connection sees an unchanging copy of the database 9566** as it existed for the point in time when the transaction first started. 9567** Subsequent changes to the database from other connections are not seen 9568** by the reader until a new read transaction is started. 9569** 9570** The sqlite3_snapshot object records state information about an historical 9571** version of the database file so that it is possible to later open a new read 9572** transaction that sees that historical version of the database rather than 9573** the most recent version. 9574*/ 9575typedef struct sqlite3_snapshot { 9576 unsigned char hidden[48]; 9577} sqlite3_snapshot; 9578 9579/* 9580** CAPI3REF: Record A Database Snapshot 9581** CONSTRUCTOR: sqlite3_snapshot 9582** 9583** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 9584** new [sqlite3_snapshot] object that records the current state of 9585** schema S in database connection D. ^On success, the 9586** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 9587** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 9588** If there is not already a read-transaction open on schema S when 9589** this function is called, one is opened automatically. 9590** 9591** The following must be true for this function to succeed. If any of 9592** the following statements are false when sqlite3_snapshot_get() is 9593** called, SQLITE_ERROR is returned. The final value of *P is undefined 9594** in this case. 9595** 9596** <ul> 9597** <li> The database handle must not be in [autocommit mode]. 9598** 9599** <li> Schema S of [database connection] D must be a [WAL mode] database. 9600** 9601** <li> There must not be a write transaction open on schema S of database 9602** connection D. 9603** 9604** <li> One or more transactions must have been written to the current wal 9605** file since it was created on disk (by any connection). This means 9606** that a snapshot cannot be taken on a wal mode database with no wal 9607** file immediately after it is first opened. At least one transaction 9608** must be written to it first. 9609** </ul> 9610** 9611** This function may also return SQLITE_NOMEM. If it is called with the 9612** database handle in autocommit mode but fails for some other reason, 9613** whether or not a read transaction is opened on schema S is undefined. 9614** 9615** The [sqlite3_snapshot] object returned from a successful call to 9616** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 9617** to avoid a memory leak. 9618** 9619** The [sqlite3_snapshot_get()] interface is only available when the 9620** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9621*/ 9622SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 9623 sqlite3 *db, 9624 const char *zSchema, 9625 sqlite3_snapshot **ppSnapshot 9626); 9627 9628/* 9629** CAPI3REF: Start a read transaction on an historical snapshot 9630** METHOD: sqlite3_snapshot 9631** 9632** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read 9633** transaction or upgrades an existing one for schema S of 9634** [database connection] D such that the read transaction refers to 9635** historical [snapshot] P, rather than the most recent change to the 9636** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK 9637** on success or an appropriate [error code] if it fails. 9638** 9639** ^In order to succeed, the database connection must not be in 9640** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there 9641** is already a read transaction open on schema S, then the database handle 9642** must have no active statements (SELECT statements that have been passed 9643** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()). 9644** SQLITE_ERROR is returned if either of these conditions is violated, or 9645** if schema S does not exist, or if the snapshot object is invalid. 9646** 9647** ^A call to sqlite3_snapshot_open() will fail to open if the specified 9648** snapshot has been overwritten by a [checkpoint]. In this case 9649** SQLITE_ERROR_SNAPSHOT is returned. 9650** 9651** If there is already a read transaction open when this function is 9652** invoked, then the same read transaction remains open (on the same 9653** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT 9654** is returned. If another error code - for example SQLITE_PROTOCOL or an 9655** SQLITE_IOERR error code - is returned, then the final state of the 9656** read transaction is undefined. If SQLITE_OK is returned, then the 9657** read transaction is now open on database snapshot P. 9658** 9659** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 9660** database connection D does not know that the database file for 9661** schema S is in [WAL mode]. A database connection might not know 9662** that the database file is in [WAL mode] if there has been no prior 9663** I/O on that database connection, or if the database entered [WAL mode] 9664** after the most recent I/O on the database connection.)^ 9665** (Hint: Run "[PRAGMA application_id]" against a newly opened 9666** database connection in order to make it ready to use snapshots.) 9667** 9668** The [sqlite3_snapshot_open()] interface is only available when the 9669** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9670*/ 9671SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 9672 sqlite3 *db, 9673 const char *zSchema, 9674 sqlite3_snapshot *pSnapshot 9675); 9676 9677/* 9678** CAPI3REF: Destroy a snapshot 9679** DESTRUCTOR: sqlite3_snapshot 9680** 9681** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 9682** The application must eventually free every [sqlite3_snapshot] object 9683** using this routine to avoid a memory leak. 9684** 9685** The [sqlite3_snapshot_free()] interface is only available when the 9686** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9687*/ 9688SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 9689 9690/* 9691** CAPI3REF: Compare the ages of two snapshot handles. 9692** METHOD: sqlite3_snapshot 9693** 9694** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 9695** of two valid snapshot handles. 9696** 9697** If the two snapshot handles are not associated with the same database 9698** file, the result of the comparison is undefined. 9699** 9700** Additionally, the result of the comparison is only valid if both of the 9701** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 9702** last time the wal file was deleted. The wal file is deleted when the 9703** database is changed back to rollback mode or when the number of database 9704** clients drops to zero. If either snapshot handle was obtained before the 9705** wal file was last deleted, the value returned by this function 9706** is undefined. 9707** 9708** Otherwise, this API returns a negative value if P1 refers to an older 9709** snapshot than P2, zero if the two handles refer to the same database 9710** snapshot, and a positive value if P1 is a newer snapshot than P2. 9711** 9712** This interface is only available if SQLite is compiled with the 9713** [SQLITE_ENABLE_SNAPSHOT] option. 9714*/ 9715SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 9716 sqlite3_snapshot *p1, 9717 sqlite3_snapshot *p2 9718); 9719 9720/* 9721** CAPI3REF: Recover snapshots from a wal file 9722** METHOD: sqlite3_snapshot 9723** 9724** If a [WAL file] remains on disk after all database connections close 9725** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control] 9726** or because the last process to have the database opened exited without 9727** calling [sqlite3_close()]) and a new connection is subsequently opened 9728** on that database and [WAL file], the [sqlite3_snapshot_open()] interface 9729** will only be able to open the last transaction added to the WAL file 9730** even though the WAL file contains other valid transactions. 9731** 9732** This function attempts to scan the WAL file associated with database zDb 9733** of database handle db and make all valid snapshots available to 9734** sqlite3_snapshot_open(). It is an error if there is already a read 9735** transaction open on the database, or if the database is not a WAL mode 9736** database. 9737** 9738** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 9739** 9740** This interface is only available if SQLite is compiled with the 9741** [SQLITE_ENABLE_SNAPSHOT] option. 9742*/ 9743SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 9744 9745/* 9746** CAPI3REF: Serialize a database 9747** 9748** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 9749** that is a serialization of the S database on [database connection] D. 9750** If P is not a NULL pointer, then the size of the database in bytes 9751** is written into *P. 9752** 9753** For an ordinary on-disk database file, the serialization is just a 9754** copy of the disk file. For an in-memory database or a "TEMP" database, 9755** the serialization is the same sequence of bytes which would be written 9756** to disk if that database where backed up to disk. 9757** 9758** The usual case is that sqlite3_serialize() copies the serialization of 9759** the database into memory obtained from [sqlite3_malloc64()] and returns 9760** a pointer to that memory. The caller is responsible for freeing the 9761** returned value to avoid a memory leak. However, if the F argument 9762** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 9763** are made, and the sqlite3_serialize() function will return a pointer 9764** to the contiguous memory representation of the database that SQLite 9765** is currently using for that database, or NULL if the no such contiguous 9766** memory representation of the database exists. A contiguous memory 9767** representation of the database will usually only exist if there has 9768** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 9769** values of D and S. 9770** The size of the database is written into *P even if the 9771** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy 9772** of the database exists. 9773** 9774** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 9775** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 9776** allocation error occurs. 9777** 9778** This interface is only available if SQLite is compiled with the 9779** [SQLITE_ENABLE_DESERIALIZE] option. 9780*/ 9781unsigned char *sqlite3_serialize( 9782 sqlite3 *db, /* The database connection */ 9783 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 9784 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 9785 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 9786); 9787 9788/* 9789** CAPI3REF: Flags for sqlite3_serialize 9790** 9791** Zero or more of the following constants can be OR-ed together for 9792** the F argument to [sqlite3_serialize(D,S,P,F)]. 9793** 9794** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 9795** a pointer to contiguous in-memory database that it is currently using, 9796** without making a copy of the database. If SQLite is not currently using 9797** a contiguous in-memory database, then this option causes 9798** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 9799** using a contiguous in-memory database if it has been initialized by a 9800** prior call to [sqlite3_deserialize()]. 9801*/ 9802#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 9803 9804/* 9805** CAPI3REF: Deserialize a database 9806** 9807** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 9808** [database connection] D to disconnect from database S and then 9809** reopen S as an in-memory database based on the serialization contained 9810** in P. The serialized database P is N bytes in size. M is the size of 9811** the buffer P, which might be larger than N. If M is larger than N, and 9812** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 9813** permitted to add content to the in-memory database as long as the total 9814** size does not exceed M bytes. 9815** 9816** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 9817** invoke sqlite3_free() on the serialization buffer when the database 9818** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 9819** SQLite will try to increase the buffer size using sqlite3_realloc64() 9820** if writes on the database cause it to grow larger than M bytes. 9821** 9822** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 9823** database is currently in a read transaction or is involved in a backup 9824** operation. 9825** 9826** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 9827** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 9828** [sqlite3_free()] is invoked on argument P prior to returning. 9829** 9830** This interface is only available if SQLite is compiled with the 9831** [SQLITE_ENABLE_DESERIALIZE] option. 9832*/ 9833int sqlite3_deserialize( 9834 sqlite3 *db, /* The database connection */ 9835 const char *zSchema, /* Which DB to reopen with the deserialization */ 9836 unsigned char *pData, /* The serialized database content */ 9837 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 9838 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 9839 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 9840); 9841 9842/* 9843** CAPI3REF: Flags for sqlite3_deserialize() 9844** 9845** The following are allowed values for 6th argument (the F argument) to 9846** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 9847** 9848** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 9849** in the P argument is held in memory obtained from [sqlite3_malloc64()] 9850** and that SQLite should take ownership of this memory and automatically 9851** free it when it has finished using it. Without this flag, the caller 9852** is responsible for freeing any dynamically allocated memory. 9853** 9854** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 9855** grow the size of the database using calls to [sqlite3_realloc64()]. This 9856** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 9857** Without this flag, the deserialized database cannot increase in size beyond 9858** the number of bytes specified by the M parameter. 9859** 9860** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 9861** should be treated as read-only. 9862*/ 9863#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 9864#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 9865#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 9866 9867/* 9868** Undo the hack that converts floating point types to integer for 9869** builds on processors without floating point support. 9870*/ 9871#ifdef SQLITE_OMIT_FLOATING_POINT 9872# undef double 9873#endif 9874 9875#ifdef __cplusplus 9876} /* End of the 'extern "C"' block */ 9877#endif 9878#endif /* SQLITE3_H */ 9879