1/* 2** 2001-09-15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are supposed to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef SQLITE3_H 34#define SQLITE3_H 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_APICALL 58# define SQLITE_APICALL 59#endif 60#ifndef SQLITE_STDCALL 61# define SQLITE_STDCALL SQLITE_APICALL 62#endif 63#ifndef SQLITE_CALLBACK 64# define SQLITE_CALLBACK 65#endif 66#ifndef SQLITE_SYSAPI 67# define SQLITE_SYSAPI 68#endif 69 70/* 71** These no-op macros are used in front of interfaces to mark those 72** interfaces as either deprecated or experimental. New applications 73** should not use deprecated interfaces - they are supported for backwards 74** compatibility only. Application writers should be aware that 75** experimental interfaces are subject to change in point releases. 76** 77** These macros used to resolve to various kinds of compiler magic that 78** would generate warning messages when they were used. But that 79** compiler magic ended up generating such a flurry of bug reports 80** that we have taken it all out and gone back to using simple 81** noop macros. 82*/ 83#define SQLITE_DEPRECATED 84#define SQLITE_EXPERIMENTAL 85 86/* 87** Ensure these symbols were not defined by some previous header file. 88*/ 89#ifdef SQLITE_VERSION 90# undef SQLITE_VERSION 91#endif 92#ifdef SQLITE_VERSION_NUMBER 93# undef SQLITE_VERSION_NUMBER 94#endif 95 96/* 97** CAPI3REF: Compile-Time Library Version Numbers 98** 99** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 100** evaluates to a string literal that is the SQLite version in the 101** format "X.Y.Z" where X is the major version number (always 3 for 102** SQLite3) and Y is the minor version number and Z is the release number.)^ 103** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 104** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 105** numbers used in [SQLITE_VERSION].)^ 106** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 107** be larger than the release from which it is derived. Either Y will 108** be held constant and Z will be incremented or else Y will be incremented 109** and Z will be reset to zero. 110** 111** Since [version 3.6.18] ([dateof:3.6.18]), 112** SQLite source code has been stored in the 113** <a href="http://www.fossil-scm.org/">Fossil configuration management 114** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 115** a string which identifies a particular check-in of SQLite 116** within its configuration management system. ^The SQLITE_SOURCE_ID 117** string contains the date and time of the check-in (UTC) and a SHA1 118** or SHA3-256 hash of the entire source tree. If the source code has 119** been edited in any way since it was last checked in, then the last 120** four hexadecimal digits of the hash may be modified. 121** 122** See also: [sqlite3_libversion()], 123** [sqlite3_libversion_number()], [sqlite3_sourceid()], 124** [sqlite_version()] and [sqlite_source_id()]. 125*/ 126#define SQLITE_VERSION "--VERS--" 127#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 128#define SQLITE_SOURCE_ID "--SOURCE-ID--" 129 130/* 131** CAPI3REF: Run-Time Library Version Numbers 132** KEYWORDS: sqlite3_version sqlite3_sourceid 133** 134** These interfaces provide the same information as the [SQLITE_VERSION], 135** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 136** but are associated with the library instead of the header file. ^(Cautious 137** programmers might include assert() statements in their application to 138** verify that values returned by these interfaces match the macros in 139** the header, and thus ensure that the application is 140** compiled with matching library and header files. 141** 142** <blockquote><pre> 143** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 144** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 ); 145** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 146** </pre></blockquote>)^ 147** 148** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 149** macro. ^The sqlite3_libversion() function returns a pointer to the 150** to the sqlite3_version[] string constant. The sqlite3_libversion() 151** function is provided for use in DLLs since DLL users usually do not have 152** direct access to string constants within the DLL. ^The 153** sqlite3_libversion_number() function returns an integer equal to 154** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns 155** a pointer to a string constant whose value is the same as the 156** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built 157** using an edited copy of [the amalgamation], then the last four characters 158** of the hash might be different from [SQLITE_SOURCE_ID].)^ 159** 160** See also: [sqlite_version()] and [sqlite_source_id()]. 161*/ 162SQLITE_EXTERN const char sqlite3_version[]; 163const char *sqlite3_libversion(void); 164const char *sqlite3_sourceid(void); 165int sqlite3_libversion_number(void); 166 167/* 168** CAPI3REF: Run-Time Library Compilation Options Diagnostics 169** 170** ^The sqlite3_compileoption_used() function returns 0 or 1 171** indicating whether the specified option was defined at 172** compile time. ^The SQLITE_ prefix may be omitted from the 173** option name passed to sqlite3_compileoption_used(). 174** 175** ^The sqlite3_compileoption_get() function allows iterating 176** over the list of options that were defined at compile time by 177** returning the N-th compile time option string. ^If N is out of range, 178** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 179** prefix is omitted from any strings returned by 180** sqlite3_compileoption_get(). 181** 182** ^Support for the diagnostic functions sqlite3_compileoption_used() 183** and sqlite3_compileoption_get() may be omitted by specifying the 184** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 185** 186** See also: SQL functions [sqlite_compileoption_used()] and 187** [sqlite_compileoption_get()] and the [compile_options pragma]. 188*/ 189#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 190int sqlite3_compileoption_used(const char *zOptName); 191const char *sqlite3_compileoption_get(int N); 192#else 193# define sqlite3_compileoption_used(X) 0 194# define sqlite3_compileoption_get(X) ((void*)0) 195#endif 196 197/* 198** CAPI3REF: Test To See If The Library Is Threadsafe 199** 200** ^The sqlite3_threadsafe() function returns zero if and only if 201** SQLite was compiled with mutexing code omitted due to the 202** [SQLITE_THREADSAFE] compile-time option being set to 0. 203** 204** SQLite can be compiled with or without mutexes. When 205** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 206** are enabled and SQLite is threadsafe. When the 207** [SQLITE_THREADSAFE] macro is 0, 208** the mutexes are omitted. Without the mutexes, it is not safe 209** to use SQLite concurrently from more than one thread. 210** 211** Enabling mutexes incurs a measurable performance penalty. 212** So if speed is of utmost importance, it makes sense to disable 213** the mutexes. But for maximum safety, mutexes should be enabled. 214** ^The default behavior is for mutexes to be enabled. 215** 216** This interface can be used by an application to make sure that the 217** version of SQLite that it is linking against was compiled with 218** the desired setting of the [SQLITE_THREADSAFE] macro. 219** 220** This interface only reports on the compile-time mutex setting 221** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 222** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 223** can be fully or partially disabled using a call to [sqlite3_config()] 224** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 225** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 226** sqlite3_threadsafe() function shows only the compile-time setting of 227** thread safety, not any run-time changes to that setting made by 228** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 229** is unchanged by calls to sqlite3_config().)^ 230** 231** See the [threading mode] documentation for additional information. 232*/ 233int sqlite3_threadsafe(void); 234 235/* 236** CAPI3REF: Database Connection Handle 237** KEYWORDS: {database connection} {database connections} 238** 239** Each open SQLite database is represented by a pointer to an instance of 240** the opaque structure named "sqlite3". It is useful to think of an sqlite3 241** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 242** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 243** and [sqlite3_close_v2()] are its destructors. There are many other 244** interfaces (such as 245** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 246** [sqlite3_busy_timeout()] to name but three) that are methods on an 247** sqlite3 object. 248*/ 249typedef struct sqlite3 sqlite3; 250 251/* 252** CAPI3REF: 64-Bit Integer Types 253** KEYWORDS: sqlite_int64 sqlite_uint64 254** 255** Because there is no cross-platform way to specify 64-bit integer types 256** SQLite includes typedefs for 64-bit signed and unsigned integers. 257** 258** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 259** The sqlite_int64 and sqlite_uint64 types are supported for backwards 260** compatibility only. 261** 262** ^The sqlite3_int64 and sqlite_int64 types can store integer values 263** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 264** sqlite3_uint64 and sqlite_uint64 types can store integer values 265** between 0 and +18446744073709551615 inclusive. 266*/ 267#ifdef SQLITE_INT64_TYPE 268 typedef SQLITE_INT64_TYPE sqlite_int64; 269# ifdef SQLITE_UINT64_TYPE 270 typedef SQLITE_UINT64_TYPE sqlite_uint64; 271# else 272 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 273# endif 274#elif defined(_MSC_VER) || defined(__BORLANDC__) 275 typedef __int64 sqlite_int64; 276 typedef unsigned __int64 sqlite_uint64; 277#else 278 typedef long long int sqlite_int64; 279 typedef unsigned long long int sqlite_uint64; 280#endif 281typedef sqlite_int64 sqlite3_int64; 282typedef sqlite_uint64 sqlite3_uint64; 283 284/* 285** If compiling for a processor that lacks floating point support, 286** substitute integer for floating-point. 287*/ 288#ifdef SQLITE_OMIT_FLOATING_POINT 289# define double sqlite3_int64 290#endif 291 292/* 293** CAPI3REF: Closing A Database Connection 294** DESTRUCTOR: sqlite3 295** 296** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 297** for the [sqlite3] object. 298** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 299** the [sqlite3] object is successfully destroyed and all associated 300** resources are deallocated. 301** 302** Ideally, applications should [sqlite3_finalize | finalize] all 303** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and 304** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 305** with the [sqlite3] object prior to attempting to close the object. 306** ^If the database connection is associated with unfinalized prepared 307** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then 308** sqlite3_close() will leave the database connection open and return 309** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared 310** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups, 311** it returns [SQLITE_OK] regardless, but instead of deallocating the database 312** connection immediately, it marks the database connection as an unusable 313** "zombie" and makes arrangements to automatically deallocate the database 314** connection after all prepared statements are finalized, all BLOB handles 315** are closed, and all backups have finished. The sqlite3_close_v2() interface 316** is intended for use with host languages that are garbage collected, and 317** where the order in which destructors are called is arbitrary. 318** 319** ^If an [sqlite3] object is destroyed while a transaction is open, 320** the transaction is automatically rolled back. 321** 322** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 323** must be either a NULL 324** pointer or an [sqlite3] object pointer obtained 325** from [sqlite3_open()], [sqlite3_open16()], or 326** [sqlite3_open_v2()], and not previously closed. 327** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 328** argument is a harmless no-op. 329*/ 330int sqlite3_close(sqlite3*); 331int sqlite3_close_v2(sqlite3*); 332 333/* 334** The type for a callback function. 335** This is legacy and deprecated. It is included for historical 336** compatibility and is not documented. 337*/ 338typedef int (*sqlite3_callback)(void*,int,char**, char**); 339 340/* 341** CAPI3REF: One-Step Query Execution Interface 342** METHOD: sqlite3 343** 344** The sqlite3_exec() interface is a convenience wrapper around 345** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 346** that allows an application to run multiple statements of SQL 347** without having to use a lot of C code. 348** 349** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 350** semicolon-separate SQL statements passed into its 2nd argument, 351** in the context of the [database connection] passed in as its 1st 352** argument. ^If the callback function of the 3rd argument to 353** sqlite3_exec() is not NULL, then it is invoked for each result row 354** coming out of the evaluated SQL statements. ^The 4th argument to 355** sqlite3_exec() is relayed through to the 1st argument of each 356** callback invocation. ^If the callback pointer to sqlite3_exec() 357** is NULL, then no callback is ever invoked and result rows are 358** ignored. 359** 360** ^If an error occurs while evaluating the SQL statements passed into 361** sqlite3_exec(), then execution of the current statement stops and 362** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 363** is not NULL then any error message is written into memory obtained 364** from [sqlite3_malloc()] and passed back through the 5th parameter. 365** To avoid memory leaks, the application should invoke [sqlite3_free()] 366** on error message strings returned through the 5th parameter of 367** sqlite3_exec() after the error message string is no longer needed. 368** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 369** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 370** NULL before returning. 371** 372** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 373** routine returns SQLITE_ABORT without invoking the callback again and 374** without running any subsequent SQL statements. 375** 376** ^The 2nd argument to the sqlite3_exec() callback function is the 377** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 378** callback is an array of pointers to strings obtained as if from 379** [sqlite3_column_text()], one for each column. ^If an element of a 380** result row is NULL then the corresponding string pointer for the 381** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 382** sqlite3_exec() callback is an array of pointers to strings where each 383** entry represents the name of corresponding result column as obtained 384** from [sqlite3_column_name()]. 385** 386** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 387** to an empty string, or a pointer that contains only whitespace and/or 388** SQL comments, then no SQL statements are evaluated and the database 389** is not changed. 390** 391** Restrictions: 392** 393** <ul> 394** <li> The application must ensure that the 1st parameter to sqlite3_exec() 395** is a valid and open [database connection]. 396** <li> The application must not close the [database connection] specified by 397** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 398** <li> The application must not modify the SQL statement text passed into 399** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 400** </ul> 401*/ 402int sqlite3_exec( 403 sqlite3*, /* An open database */ 404 const char *sql, /* SQL to be evaluated */ 405 int (*callback)(void*,int,char**,char**), /* Callback function */ 406 void *, /* 1st argument to callback */ 407 char **errmsg /* Error msg written here */ 408); 409 410/* 411** CAPI3REF: Result Codes 412** KEYWORDS: {result code definitions} 413** 414** Many SQLite functions return an integer result code from the set shown 415** here in order to indicate success or failure. 416** 417** New error codes may be added in future versions of SQLite. 418** 419** See also: [extended result code definitions] 420*/ 421#define SQLITE_OK 0 /* Successful result */ 422/* beginning-of-error-codes */ 423#define SQLITE_ERROR 1 /* Generic error */ 424#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 425#define SQLITE_PERM 3 /* Access permission denied */ 426#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 427#define SQLITE_BUSY 5 /* The database file is locked */ 428#define SQLITE_LOCKED 6 /* A table in the database is locked */ 429#define SQLITE_NOMEM 7 /* A malloc() failed */ 430#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 431#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 432#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 433#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 434#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 435#define SQLITE_FULL 13 /* Insertion failed because database is full */ 436#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 437#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 438#define SQLITE_EMPTY 16 /* Internal use only */ 439#define SQLITE_SCHEMA 17 /* The database schema changed */ 440#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 441#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 442#define SQLITE_MISMATCH 20 /* Data type mismatch */ 443#define SQLITE_MISUSE 21 /* Library used incorrectly */ 444#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 445#define SQLITE_AUTH 23 /* Authorization denied */ 446#define SQLITE_FORMAT 24 /* Not used */ 447#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 448#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 449#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 450#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 451#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 452#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 453/* end-of-error-codes */ 454 455/* 456** CAPI3REF: Extended Result Codes 457** KEYWORDS: {extended result code definitions} 458** 459** In its default configuration, SQLite API routines return one of 30 integer 460** [result codes]. However, experience has shown that many of 461** these result codes are too coarse-grained. They do not provide as 462** much information about problems as programmers might like. In an effort to 463** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 464** and later) include 465** support for additional result codes that provide more detailed information 466** about errors. These [extended result codes] are enabled or disabled 467** on a per database connection basis using the 468** [sqlite3_extended_result_codes()] API. Or, the extended code for 469** the most recent error can be obtained using 470** [sqlite3_extended_errcode()]. 471*/ 472#define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8)) 473#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8)) 474#define SQLITE_ERROR_SNAPSHOT (SQLITE_ERROR | (3<<8)) 475#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 476#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 477#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 478#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 479#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 480#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 481#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 482#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 483#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 484#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 485#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 486#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 487#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 488#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 489#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 490#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 491#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 492#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 493#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 494#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 495#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 496#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 497#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 498#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 499#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 500#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 501#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 502#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 503#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 504#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 505#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 506#define SQLITE_IOERR_DATA (SQLITE_IOERR | (32<<8)) 507#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 508#define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8)) 509#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 510#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 511#define SQLITE_BUSY_TIMEOUT (SQLITE_BUSY | (3<<8)) 512#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 513#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 514#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 515#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 516#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */ 517#define SQLITE_CANTOPEN_SYMLINK (SQLITE_CANTOPEN | (6<<8)) 518#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 519#define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8)) 520#define SQLITE_CORRUPT_INDEX (SQLITE_CORRUPT | (3<<8)) 521#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 522#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 523#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 524#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 525#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8)) 526#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8)) 527#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 528#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 529#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 530#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 531#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 532#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 533#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 534#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 535#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 536#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 537#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 538#define SQLITE_CONSTRAINT_PINNED (SQLITE_CONSTRAINT |(11<<8)) 539#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 540#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 541#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 542#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 543#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 544#define SQLITE_OK_SYMLINK (SQLITE_OK | (2<<8)) 545 546/* 547** CAPI3REF: Flags For File Open Operations 548** 549** These bit values are intended for use in the 550** 3rd parameter to the [sqlite3_open_v2()] interface and 551** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 552*/ 553#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 554#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 555#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 556#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 557#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 558#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 559#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 560#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 561#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 562#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 563#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 564#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 565#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 566#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 567#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 568#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 569#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 570#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 571#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 572#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 573#define SQLITE_OPEN_NOFOLLOW 0x01000000 /* Ok for sqlite3_open_v2() */ 574 575/* Reserved: 0x00F00000 */ 576 577/* 578** CAPI3REF: Device Characteristics 579** 580** The xDeviceCharacteristics method of the [sqlite3_io_methods] 581** object returns an integer which is a vector of these 582** bit values expressing I/O characteristics of the mass storage 583** device that holds the file that the [sqlite3_io_methods] 584** refers to. 585** 586** The SQLITE_IOCAP_ATOMIC property means that all writes of 587** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 588** mean that writes of blocks that are nnn bytes in size and 589** are aligned to an address which is an integer multiple of 590** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 591** that when data is appended to a file, the data is appended 592** first then the size of the file is extended, never the other 593** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 594** information is written to disk in the same order as calls 595** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 596** after reboot following a crash or power loss, the only bytes in a 597** file that were written at the application level might have changed 598** and that adjacent bytes, even bytes within the same sector are 599** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 600** flag indicates that a file cannot be deleted when open. The 601** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 602** read-only media and cannot be changed even by processes with 603** elevated privileges. 604** 605** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 606** filesystem supports doing multiple write operations atomically when those 607** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 608** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 609*/ 610#define SQLITE_IOCAP_ATOMIC 0x00000001 611#define SQLITE_IOCAP_ATOMIC512 0x00000002 612#define SQLITE_IOCAP_ATOMIC1K 0x00000004 613#define SQLITE_IOCAP_ATOMIC2K 0x00000008 614#define SQLITE_IOCAP_ATOMIC4K 0x00000010 615#define SQLITE_IOCAP_ATOMIC8K 0x00000020 616#define SQLITE_IOCAP_ATOMIC16K 0x00000040 617#define SQLITE_IOCAP_ATOMIC32K 0x00000080 618#define SQLITE_IOCAP_ATOMIC64K 0x00000100 619#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 620#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 621#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 622#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 623#define SQLITE_IOCAP_IMMUTABLE 0x00002000 624#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 625 626/* 627** CAPI3REF: File Locking Levels 628** 629** SQLite uses one of these integer values as the second 630** argument to calls it makes to the xLock() and xUnlock() methods 631** of an [sqlite3_io_methods] object. 632*/ 633#define SQLITE_LOCK_NONE 0 634#define SQLITE_LOCK_SHARED 1 635#define SQLITE_LOCK_RESERVED 2 636#define SQLITE_LOCK_PENDING 3 637#define SQLITE_LOCK_EXCLUSIVE 4 638 639/* 640** CAPI3REF: Synchronization Type Flags 641** 642** When SQLite invokes the xSync() method of an 643** [sqlite3_io_methods] object it uses a combination of 644** these integer values as the second argument. 645** 646** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 647** sync operation only needs to flush data to mass storage. Inode 648** information need not be flushed. If the lower four bits of the flag 649** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 650** If the lower four bits equal SQLITE_SYNC_FULL, that means 651** to use Mac OS X style fullsync instead of fsync(). 652** 653** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 654** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 655** settings. The [synchronous pragma] determines when calls to the 656** xSync VFS method occur and applies uniformly across all platforms. 657** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 658** energetic or rigorous or forceful the sync operations are and 659** only make a difference on Mac OSX for the default SQLite code. 660** (Third-party VFS implementations might also make the distinction 661** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 662** operating systems natively supported by SQLite, only Mac OSX 663** cares about the difference.) 664*/ 665#define SQLITE_SYNC_NORMAL 0x00002 666#define SQLITE_SYNC_FULL 0x00003 667#define SQLITE_SYNC_DATAONLY 0x00010 668 669/* 670** CAPI3REF: OS Interface Open File Handle 671** 672** An [sqlite3_file] object represents an open file in the 673** [sqlite3_vfs | OS interface layer]. Individual OS interface 674** implementations will 675** want to subclass this object by appending additional fields 676** for their own use. The pMethods entry is a pointer to an 677** [sqlite3_io_methods] object that defines methods for performing 678** I/O operations on the open file. 679*/ 680typedef struct sqlite3_file sqlite3_file; 681struct sqlite3_file { 682 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 683}; 684 685/* 686** CAPI3REF: OS Interface File Virtual Methods Object 687** 688** Every file opened by the [sqlite3_vfs.xOpen] method populates an 689** [sqlite3_file] object (or, more commonly, a subclass of the 690** [sqlite3_file] object) with a pointer to an instance of this object. 691** This object defines the methods used to perform various operations 692** against the open file represented by the [sqlite3_file] object. 693** 694** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 695** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 696** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 697** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 698** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 699** to NULL. 700** 701** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 702** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 703** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 704** flag may be ORed in to indicate that only the data of the file 705** and not its inode needs to be synced. 706** 707** The integer values to xLock() and xUnlock() are one of 708** <ul> 709** <li> [SQLITE_LOCK_NONE], 710** <li> [SQLITE_LOCK_SHARED], 711** <li> [SQLITE_LOCK_RESERVED], 712** <li> [SQLITE_LOCK_PENDING], or 713** <li> [SQLITE_LOCK_EXCLUSIVE]. 714** </ul> 715** xLock() increases the lock. xUnlock() decreases the lock. 716** The xCheckReservedLock() method checks whether any database connection, 717** either in this process or in some other process, is holding a RESERVED, 718** PENDING, or EXCLUSIVE lock on the file. It returns true 719** if such a lock exists and false otherwise. 720** 721** The xFileControl() method is a generic interface that allows custom 722** VFS implementations to directly control an open file using the 723** [sqlite3_file_control()] interface. The second "op" argument is an 724** integer opcode. The third argument is a generic pointer intended to 725** point to a structure that may contain arguments or space in which to 726** write return values. Potential uses for xFileControl() might be 727** functions to enable blocking locks with timeouts, to change the 728** locking strategy (for example to use dot-file locks), to inquire 729** about the status of a lock, or to break stale locks. The SQLite 730** core reserves all opcodes less than 100 for its own use. 731** A [file control opcodes | list of opcodes] less than 100 is available. 732** Applications that define a custom xFileControl method should use opcodes 733** greater than 100 to avoid conflicts. VFS implementations should 734** return [SQLITE_NOTFOUND] for file control opcodes that they do not 735** recognize. 736** 737** The xSectorSize() method returns the sector size of the 738** device that underlies the file. The sector size is the 739** minimum write that can be performed without disturbing 740** other bytes in the file. The xDeviceCharacteristics() 741** method returns a bit vector describing behaviors of the 742** underlying device: 743** 744** <ul> 745** <li> [SQLITE_IOCAP_ATOMIC] 746** <li> [SQLITE_IOCAP_ATOMIC512] 747** <li> [SQLITE_IOCAP_ATOMIC1K] 748** <li> [SQLITE_IOCAP_ATOMIC2K] 749** <li> [SQLITE_IOCAP_ATOMIC4K] 750** <li> [SQLITE_IOCAP_ATOMIC8K] 751** <li> [SQLITE_IOCAP_ATOMIC16K] 752** <li> [SQLITE_IOCAP_ATOMIC32K] 753** <li> [SQLITE_IOCAP_ATOMIC64K] 754** <li> [SQLITE_IOCAP_SAFE_APPEND] 755** <li> [SQLITE_IOCAP_SEQUENTIAL] 756** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 757** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 758** <li> [SQLITE_IOCAP_IMMUTABLE] 759** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 760** </ul> 761** 762** The SQLITE_IOCAP_ATOMIC property means that all writes of 763** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 764** mean that writes of blocks that are nnn bytes in size and 765** are aligned to an address which is an integer multiple of 766** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 767** that when data is appended to a file, the data is appended 768** first then the size of the file is extended, never the other 769** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 770** information is written to disk in the same order as calls 771** to xWrite(). 772** 773** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 774** in the unread portions of the buffer with zeros. A VFS that 775** fails to zero-fill short reads might seem to work. However, 776** failure to zero-fill short reads will eventually lead to 777** database corruption. 778*/ 779typedef struct sqlite3_io_methods sqlite3_io_methods; 780struct sqlite3_io_methods { 781 int iVersion; 782 int (*xClose)(sqlite3_file*); 783 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 784 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 785 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 786 int (*xSync)(sqlite3_file*, int flags); 787 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 788 int (*xLock)(sqlite3_file*, int); 789 int (*xUnlock)(sqlite3_file*, int); 790 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 791 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 792 int (*xSectorSize)(sqlite3_file*); 793 int (*xDeviceCharacteristics)(sqlite3_file*); 794 /* Methods above are valid for version 1 */ 795 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 796 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 797 void (*xShmBarrier)(sqlite3_file*); 798 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 799 /* Methods above are valid for version 2 */ 800 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 801 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 802 /* Methods above are valid for version 3 */ 803 /* Additional methods may be added in future releases */ 804}; 805 806/* 807** CAPI3REF: Standard File Control Opcodes 808** KEYWORDS: {file control opcodes} {file control opcode} 809** 810** These integer constants are opcodes for the xFileControl method 811** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 812** interface. 813** 814** <ul> 815** <li>[[SQLITE_FCNTL_LOCKSTATE]] 816** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 817** opcode causes the xFileControl method to write the current state of 818** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 819** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 820** into an integer that the pArg argument points to. This capability 821** is used during testing and is only available when the SQLITE_TEST 822** compile-time option is used. 823** 824** <li>[[SQLITE_FCNTL_SIZE_HINT]] 825** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 826** layer a hint of how large the database file will grow to be during the 827** current transaction. This hint is not guaranteed to be accurate but it 828** is often close. The underlying VFS might choose to preallocate database 829** file space based on this hint in order to help writes to the database 830** file run faster. 831** 832** <li>[[SQLITE_FCNTL_SIZE_LIMIT]] 833** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that 834** implements [sqlite3_deserialize()] to set an upper bound on the size 835** of the in-memory database. The argument is a pointer to a [sqlite3_int64]. 836** If the integer pointed to is negative, then it is filled in with the 837** current limit. Otherwise the limit is set to the larger of the value 838** of the integer pointed to and the current database size. The integer 839** pointed to is set to the new limit. 840** 841** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 842** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 843** extends and truncates the database file in chunks of a size specified 844** by the user. The fourth argument to [sqlite3_file_control()] should 845** point to an integer (type int) containing the new chunk-size to use 846** for the nominated database. Allocating database file space in large 847** chunks (say 1MB at a time), may reduce file-system fragmentation and 848** improve performance on some systems. 849** 850** <li>[[SQLITE_FCNTL_FILE_POINTER]] 851** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 852** to the [sqlite3_file] object associated with a particular database 853** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 854** 855** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 856** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 857** to the [sqlite3_file] object associated with the journal file (either 858** the [rollback journal] or the [write-ahead log]) for a particular database 859** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 860** 861** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 862** No longer in use. 863** 864** <li>[[SQLITE_FCNTL_SYNC]] 865** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 866** sent to the VFS immediately before the xSync method is invoked on a 867** database file descriptor. Or, if the xSync method is not invoked 868** because the user has configured SQLite with 869** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 870** of the xSync method. In most cases, the pointer argument passed with 871** this file-control is NULL. However, if the database file is being synced 872** as part of a multi-database commit, the argument points to a nul-terminated 873** string containing the transactions master-journal file name. VFSes that 874** do not need this signal should silently ignore this opcode. Applications 875** should not call [sqlite3_file_control()] with this opcode as doing so may 876** disrupt the operation of the specialized VFSes that do require it. 877** 878** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 879** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 880** and sent to the VFS after a transaction has been committed immediately 881** but before the database is unlocked. VFSes that do not need this signal 882** should silently ignore this opcode. Applications should not call 883** [sqlite3_file_control()] with this opcode as doing so may disrupt the 884** operation of the specialized VFSes that do require it. 885** 886** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 887** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 888** retry counts and intervals for certain disk I/O operations for the 889** windows [VFS] in order to provide robustness in the presence of 890** anti-virus programs. By default, the windows VFS will retry file read, 891** file write, and file delete operations up to 10 times, with a delay 892** of 25 milliseconds before the first retry and with the delay increasing 893** by an additional 25 milliseconds with each subsequent retry. This 894** opcode allows these two values (10 retries and 25 milliseconds of delay) 895** to be adjusted. The values are changed for all database connections 896** within the same process. The argument is a pointer to an array of two 897** integers where the first integer is the new retry count and the second 898** integer is the delay. If either integer is negative, then the setting 899** is not changed but instead the prior value of that setting is written 900** into the array entry, allowing the current retry settings to be 901** interrogated. The zDbName parameter is ignored. 902** 903** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 904** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 905** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 906** write ahead log ([WAL file]) and shared memory 907** files used for transaction control 908** are automatically deleted when the latest connection to the database 909** closes. Setting persistent WAL mode causes those files to persist after 910** close. Persisting the files is useful when other processes that do not 911** have write permission on the directory containing the database file want 912** to read the database file, as the WAL and shared memory files must exist 913** in order for the database to be readable. The fourth parameter to 914** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 915** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 916** WAL mode. If the integer is -1, then it is overwritten with the current 917** WAL persistence setting. 918** 919** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 920** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 921** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 922** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 923** xDeviceCharacteristics methods. The fourth parameter to 924** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 925** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 926** mode. If the integer is -1, then it is overwritten with the current 927** zero-damage mode setting. 928** 929** <li>[[SQLITE_FCNTL_OVERWRITE]] 930** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 931** a write transaction to indicate that, unless it is rolled back for some 932** reason, the entire database file will be overwritten by the current 933** transaction. This is used by VACUUM operations. 934** 935** <li>[[SQLITE_FCNTL_VFSNAME]] 936** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 937** all [VFSes] in the VFS stack. The names are of all VFS shims and the 938** final bottom-level VFS are written into memory obtained from 939** [sqlite3_malloc()] and the result is stored in the char* variable 940** that the fourth parameter of [sqlite3_file_control()] points to. 941** The caller is responsible for freeing the memory when done. As with 942** all file-control actions, there is no guarantee that this will actually 943** do anything. Callers should initialize the char* variable to a NULL 944** pointer in case this file-control is not implemented. This file-control 945** is intended for diagnostic use only. 946** 947** <li>[[SQLITE_FCNTL_VFS_POINTER]] 948** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 949** [VFSes] currently in use. ^(The argument X in 950** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 951** of type "[sqlite3_vfs] **". This opcodes will set *X 952** to a pointer to the top-level VFS.)^ 953** ^When there are multiple VFS shims in the stack, this opcode finds the 954** upper-most shim only. 955** 956** <li>[[SQLITE_FCNTL_PRAGMA]] 957** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 958** file control is sent to the open [sqlite3_file] object corresponding 959** to the database file to which the pragma statement refers. ^The argument 960** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 961** pointers to strings (char**) in which the second element of the array 962** is the name of the pragma and the third element is the argument to the 963** pragma or NULL if the pragma has no argument. ^The handler for an 964** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 965** of the char** argument point to a string obtained from [sqlite3_mprintf()] 966** or the equivalent and that string will become the result of the pragma or 967** the error message if the pragma fails. ^If the 968** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 969** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 970** file control returns [SQLITE_OK], then the parser assumes that the 971** VFS has handled the PRAGMA itself and the parser generates a no-op 972** prepared statement if result string is NULL, or that returns a copy 973** of the result string if the string is non-NULL. 974** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 975** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 976** that the VFS encountered an error while handling the [PRAGMA] and the 977** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 978** file control occurs at the beginning of pragma statement analysis and so 979** it is able to override built-in [PRAGMA] statements. 980** 981** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 982** ^The [SQLITE_FCNTL_BUSYHANDLER] 983** file-control may be invoked by SQLite on the database file handle 984** shortly after it is opened in order to provide a custom VFS with access 985** to the connection's busy-handler callback. The argument is of type (void**) 986** - an array of two (void *) values. The first (void *) actually points 987** to a function of type (int (*)(void *)). In order to invoke the connection's 988** busy-handler, this function should be invoked with the second (void *) in 989** the array as the only argument. If it returns non-zero, then the operation 990** should be retried. If it returns zero, the custom VFS should abandon the 991** current operation. 992** 993** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 994** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 995** to have SQLite generate a 996** temporary filename using the same algorithm that is followed to generate 997** temporary filenames for TEMP tables and other internal uses. The 998** argument should be a char** which will be filled with the filename 999** written into memory obtained from [sqlite3_malloc()]. The caller should 1000** invoke [sqlite3_free()] on the result to avoid a memory leak. 1001** 1002** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 1003** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 1004** maximum number of bytes that will be used for memory-mapped I/O. 1005** The argument is a pointer to a value of type sqlite3_int64 that 1006** is an advisory maximum number of bytes in the file to memory map. The 1007** pointer is overwritten with the old value. The limit is not changed if 1008** the value originally pointed to is negative, and so the current limit 1009** can be queried by passing in a pointer to a negative number. This 1010** file-control is used internally to implement [PRAGMA mmap_size]. 1011** 1012** <li>[[SQLITE_FCNTL_TRACE]] 1013** The [SQLITE_FCNTL_TRACE] file control provides advisory information 1014** to the VFS about what the higher layers of the SQLite stack are doing. 1015** This file control is used by some VFS activity tracing [shims]. 1016** The argument is a zero-terminated string. Higher layers in the 1017** SQLite stack may generate instances of this file control if 1018** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 1019** 1020** <li>[[SQLITE_FCNTL_HAS_MOVED]] 1021** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 1022** pointer to an integer and it writes a boolean into that integer depending 1023** on whether or not the file has been renamed, moved, or deleted since it 1024** was first opened. 1025** 1026** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1027** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1028** underlying native file handle associated with a file handle. This file 1029** control interprets its argument as a pointer to a native file handle and 1030** writes the resulting value there. 1031** 1032** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1033** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1034** opcode causes the xFileControl method to swap the file handle with the one 1035** pointed to by the pArg argument. This capability is used during testing 1036** and only needs to be supported when SQLITE_TEST is defined. 1037** 1038** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1039** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1040** be advantageous to block on the next WAL lock if the lock is not immediately 1041** available. The WAL subsystem issues this signal during rare 1042** circumstances in order to fix a problem with priority inversion. 1043** Applications should <em>not</em> use this file-control. 1044** 1045** <li>[[SQLITE_FCNTL_ZIPVFS]] 1046** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1047** VFS should return SQLITE_NOTFOUND for this opcode. 1048** 1049** <li>[[SQLITE_FCNTL_RBU]] 1050** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1051** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1052** this opcode. 1053** 1054** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1055** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1056** the file descriptor is placed in "batch write mode", which 1057** means all subsequent write operations will be deferred and done 1058** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1059** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1060** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1061** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1062** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1063** no VFS interface calls on the same [sqlite3_file] file descriptor 1064** except for calls to the xWrite method and the xFileControl method 1065** with [SQLITE_FCNTL_SIZE_HINT]. 1066** 1067** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1068** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1069** operations since the previous successful call to 1070** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1071** This file control returns [SQLITE_OK] if and only if the writes were 1072** all performed successfully and have been committed to persistent storage. 1073** ^Regardless of whether or not it is successful, this file control takes 1074** the file descriptor out of batch write mode so that all subsequent 1075** write operations are independent. 1076** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1077** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1078** 1079** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1080** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1081** operations since the previous successful call to 1082** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1083** ^This file control takes the file descriptor out of batch write mode 1084** so that all subsequent write operations are independent. 1085** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1086** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1087** 1088** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]] 1089** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS 1090** to block for up to M milliseconds before failing when attempting to 1091** obtain a file lock using the xLock or xShmLock methods of the VFS. 1092** The parameter is a pointer to a 32-bit signed integer that contains 1093** the value that M is to be set to. Before returning, the 32-bit signed 1094** integer is overwritten with the previous value of M. 1095** 1096** <li>[[SQLITE_FCNTL_DATA_VERSION]] 1097** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to 1098** a database file. The argument is a pointer to a 32-bit unsigned integer. 1099** The "data version" for the pager is written into the pointer. The 1100** "data version" changes whenever any change occurs to the corresponding 1101** database file, either through SQL statements on the same database 1102** connection or through transactions committed by separate database 1103** connections possibly in other processes. The [sqlite3_total_changes()] 1104** interface can be used to find if any database on the connection has changed, 1105** but that interface responds to changes on TEMP as well as MAIN and does 1106** not provide a mechanism to detect changes to MAIN only. Also, the 1107** [sqlite3_total_changes()] interface responds to internal changes only and 1108** omits changes made by other database connections. The 1109** [PRAGMA data_version] command provides a mechanism to detect changes to 1110** a single attached database that occur due to other database connections, 1111** but omits changes implemented by the database connection on which it is 1112** called. This file control is the only mechanism to detect changes that 1113** happen either internally or externally and that are associated with 1114** a particular attached database. 1115** 1116** <li>[[SQLITE_FCNTL_CKPT_START]] 1117** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint 1118** in wal mode before the client starts to copy pages from the wal 1119** file to the database file. 1120** 1121** <li>[[SQLITE_FCNTL_CKPT_DONE]] 1122** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint 1123** in wal mode after the client has finished copying pages from the wal 1124** file to the database file, but before the *-shm file is updated to 1125** record the fact that the pages have been checkpointed. 1126** </ul> 1127*/ 1128#define SQLITE_FCNTL_LOCKSTATE 1 1129#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1130#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1131#define SQLITE_FCNTL_LAST_ERRNO 4 1132#define SQLITE_FCNTL_SIZE_HINT 5 1133#define SQLITE_FCNTL_CHUNK_SIZE 6 1134#define SQLITE_FCNTL_FILE_POINTER 7 1135#define SQLITE_FCNTL_SYNC_OMITTED 8 1136#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1137#define SQLITE_FCNTL_PERSIST_WAL 10 1138#define SQLITE_FCNTL_OVERWRITE 11 1139#define SQLITE_FCNTL_VFSNAME 12 1140#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1141#define SQLITE_FCNTL_PRAGMA 14 1142#define SQLITE_FCNTL_BUSYHANDLER 15 1143#define SQLITE_FCNTL_TEMPFILENAME 16 1144#define SQLITE_FCNTL_MMAP_SIZE 18 1145#define SQLITE_FCNTL_TRACE 19 1146#define SQLITE_FCNTL_HAS_MOVED 20 1147#define SQLITE_FCNTL_SYNC 21 1148#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1149#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1150#define SQLITE_FCNTL_WAL_BLOCK 24 1151#define SQLITE_FCNTL_ZIPVFS 25 1152#define SQLITE_FCNTL_RBU 26 1153#define SQLITE_FCNTL_VFS_POINTER 27 1154#define SQLITE_FCNTL_JOURNAL_POINTER 28 1155#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1156#define SQLITE_FCNTL_PDB 30 1157#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1158#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1159#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1160#define SQLITE_FCNTL_LOCK_TIMEOUT 34 1161#define SQLITE_FCNTL_DATA_VERSION 35 1162#define SQLITE_FCNTL_SIZE_LIMIT 36 1163#define SQLITE_FCNTL_CKPT_DONE 37 1164#define SQLITE_FCNTL_RESERVE_BYTES 38 1165#define SQLITE_FCNTL_CKPT_START 39 1166 1167/* deprecated names */ 1168#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1169#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1170#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1171 1172 1173/* 1174** CAPI3REF: Mutex Handle 1175** 1176** The mutex module within SQLite defines [sqlite3_mutex] to be an 1177** abstract type for a mutex object. The SQLite core never looks 1178** at the internal representation of an [sqlite3_mutex]. It only 1179** deals with pointers to the [sqlite3_mutex] object. 1180** 1181** Mutexes are created using [sqlite3_mutex_alloc()]. 1182*/ 1183typedef struct sqlite3_mutex sqlite3_mutex; 1184 1185/* 1186** CAPI3REF: Loadable Extension Thunk 1187** 1188** A pointer to the opaque sqlite3_api_routines structure is passed as 1189** the third parameter to entry points of [loadable extensions]. This 1190** structure must be typedefed in order to work around compiler warnings 1191** on some platforms. 1192*/ 1193typedef struct sqlite3_api_routines sqlite3_api_routines; 1194 1195/* 1196** CAPI3REF: OS Interface Object 1197** 1198** An instance of the sqlite3_vfs object defines the interface between 1199** the SQLite core and the underlying operating system. The "vfs" 1200** in the name of the object stands for "virtual file system". See 1201** the [VFS | VFS documentation] for further information. 1202** 1203** The VFS interface is sometimes extended by adding new methods onto 1204** the end. Each time such an extension occurs, the iVersion field 1205** is incremented. The iVersion value started out as 1 in 1206** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1207** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1208** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1209** may be appended to the sqlite3_vfs object and the iVersion value 1210** may increase again in future versions of SQLite. 1211** Note that due to an oversight, the structure 1212** of the sqlite3_vfs object changed in the transition from 1213** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1214** and yet the iVersion field was not increased. 1215** 1216** The szOsFile field is the size of the subclassed [sqlite3_file] 1217** structure used by this VFS. mxPathname is the maximum length of 1218** a pathname in this VFS. 1219** 1220** Registered sqlite3_vfs objects are kept on a linked list formed by 1221** the pNext pointer. The [sqlite3_vfs_register()] 1222** and [sqlite3_vfs_unregister()] interfaces manage this list 1223** in a thread-safe way. The [sqlite3_vfs_find()] interface 1224** searches the list. Neither the application code nor the VFS 1225** implementation should use the pNext pointer. 1226** 1227** The pNext field is the only field in the sqlite3_vfs 1228** structure that SQLite will ever modify. SQLite will only access 1229** or modify this field while holding a particular static mutex. 1230** The application should never modify anything within the sqlite3_vfs 1231** object once the object has been registered. 1232** 1233** The zName field holds the name of the VFS module. The name must 1234** be unique across all VFS modules. 1235** 1236** [[sqlite3_vfs.xOpen]] 1237** ^SQLite guarantees that the zFilename parameter to xOpen 1238** is either a NULL pointer or string obtained 1239** from xFullPathname() with an optional suffix added. 1240** ^If a suffix is added to the zFilename parameter, it will 1241** consist of a single "-" character followed by no more than 1242** 11 alphanumeric and/or "-" characters. 1243** ^SQLite further guarantees that 1244** the string will be valid and unchanged until xClose() is 1245** called. Because of the previous sentence, 1246** the [sqlite3_file] can safely store a pointer to the 1247** filename if it needs to remember the filename for some reason. 1248** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1249** must invent its own temporary name for the file. ^Whenever the 1250** xFilename parameter is NULL it will also be the case that the 1251** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1252** 1253** The flags argument to xOpen() includes all bits set in 1254** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1255** or [sqlite3_open16()] is used, then flags includes at least 1256** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1257** If xOpen() opens a file read-only then it sets *pOutFlags to 1258** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1259** 1260** ^(SQLite will also add one of the following flags to the xOpen() 1261** call, depending on the object being opened: 1262** 1263** <ul> 1264** <li> [SQLITE_OPEN_MAIN_DB] 1265** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1266** <li> [SQLITE_OPEN_TEMP_DB] 1267** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1268** <li> [SQLITE_OPEN_TRANSIENT_DB] 1269** <li> [SQLITE_OPEN_SUBJOURNAL] 1270** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1271** <li> [SQLITE_OPEN_WAL] 1272** </ul>)^ 1273** 1274** The file I/O implementation can use the object type flags to 1275** change the way it deals with files. For example, an application 1276** that does not care about crash recovery or rollback might make 1277** the open of a journal file a no-op. Writes to this journal would 1278** also be no-ops, and any attempt to read the journal would return 1279** SQLITE_IOERR. Or the implementation might recognize that a database 1280** file will be doing page-aligned sector reads and writes in a random 1281** order and set up its I/O subsystem accordingly. 1282** 1283** SQLite might also add one of the following flags to the xOpen method: 1284** 1285** <ul> 1286** <li> [SQLITE_OPEN_DELETEONCLOSE] 1287** <li> [SQLITE_OPEN_EXCLUSIVE] 1288** </ul> 1289** 1290** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1291** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1292** will be set for TEMP databases and their journals, transient 1293** databases, and subjournals. 1294** 1295** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1296** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1297** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1298** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1299** SQLITE_OPEN_CREATE, is used to indicate that file should always 1300** be created, and that it is an error if it already exists. 1301** It is <i>not</i> used to indicate the file should be opened 1302** for exclusive access. 1303** 1304** ^At least szOsFile bytes of memory are allocated by SQLite 1305** to hold the [sqlite3_file] structure passed as the third 1306** argument to xOpen. The xOpen method does not have to 1307** allocate the structure; it should just fill it in. Note that 1308** the xOpen method must set the sqlite3_file.pMethods to either 1309** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1310** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1311** element will be valid after xOpen returns regardless of the success 1312** or failure of the xOpen call. 1313** 1314** [[sqlite3_vfs.xAccess]] 1315** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1316** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1317** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1318** to test whether a file is at least readable. The SQLITE_ACCESS_READ 1319** flag is never actually used and is not implemented in the built-in 1320** VFSes of SQLite. The file is named by the second argument and can be a 1321** directory. The xAccess method returns [SQLITE_OK] on success or some 1322** non-zero error code if there is an I/O error or if the name of 1323** the file given in the second argument is illegal. If SQLITE_OK 1324** is returned, then non-zero or zero is written into *pResOut to indicate 1325** whether or not the file is accessible. 1326** 1327** ^SQLite will always allocate at least mxPathname+1 bytes for the 1328** output buffer xFullPathname. The exact size of the output buffer 1329** is also passed as a parameter to both methods. If the output buffer 1330** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1331** handled as a fatal error by SQLite, vfs implementations should endeavor 1332** to prevent this by setting mxPathname to a sufficiently large value. 1333** 1334** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1335** interfaces are not strictly a part of the filesystem, but they are 1336** included in the VFS structure for completeness. 1337** The xRandomness() function attempts to return nBytes bytes 1338** of good-quality randomness into zOut. The return value is 1339** the actual number of bytes of randomness obtained. 1340** The xSleep() method causes the calling thread to sleep for at 1341** least the number of microseconds given. ^The xCurrentTime() 1342** method returns a Julian Day Number for the current date and time as 1343** a floating point value. 1344** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1345** Day Number multiplied by 86400000 (the number of milliseconds in 1346** a 24-hour day). 1347** ^SQLite will use the xCurrentTimeInt64() method to get the current 1348** date and time if that method is available (if iVersion is 2 or 1349** greater and the function pointer is not NULL) and will fall back 1350** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1351** 1352** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1353** are not used by the SQLite core. These optional interfaces are provided 1354** by some VFSes to facilitate testing of the VFS code. By overriding 1355** system calls with functions under its control, a test program can 1356** simulate faults and error conditions that would otherwise be difficult 1357** or impossible to induce. The set of system calls that can be overridden 1358** varies from one VFS to another, and from one version of the same VFS to the 1359** next. Applications that use these interfaces must be prepared for any 1360** or all of these interfaces to be NULL or for their behavior to change 1361** from one release to the next. Applications must not attempt to access 1362** any of these methods if the iVersion of the VFS is less than 3. 1363*/ 1364typedef struct sqlite3_vfs sqlite3_vfs; 1365typedef void (*sqlite3_syscall_ptr)(void); 1366struct sqlite3_vfs { 1367 int iVersion; /* Structure version number (currently 3) */ 1368 int szOsFile; /* Size of subclassed sqlite3_file */ 1369 int mxPathname; /* Maximum file pathname length */ 1370 sqlite3_vfs *pNext; /* Next registered VFS */ 1371 const char *zName; /* Name of this virtual file system */ 1372 void *pAppData; /* Pointer to application-specific data */ 1373 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1374 int flags, int *pOutFlags); 1375 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1376 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1377 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1378 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1379 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1380 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1381 void (*xDlClose)(sqlite3_vfs*, void*); 1382 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1383 int (*xSleep)(sqlite3_vfs*, int microseconds); 1384 int (*xCurrentTime)(sqlite3_vfs*, double*); 1385 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1386 /* 1387 ** The methods above are in version 1 of the sqlite_vfs object 1388 ** definition. Those that follow are added in version 2 or later 1389 */ 1390 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1391 /* 1392 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1393 ** Those below are for version 3 and greater. 1394 */ 1395 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1396 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1397 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1398 /* 1399 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1400 ** New fields may be appended in future versions. The iVersion 1401 ** value will increment whenever this happens. 1402 */ 1403}; 1404 1405/* 1406** CAPI3REF: Flags for the xAccess VFS method 1407** 1408** These integer constants can be used as the third parameter to 1409** the xAccess method of an [sqlite3_vfs] object. They determine 1410** what kind of permissions the xAccess method is looking for. 1411** With SQLITE_ACCESS_EXISTS, the xAccess method 1412** simply checks whether the file exists. 1413** With SQLITE_ACCESS_READWRITE, the xAccess method 1414** checks whether the named directory is both readable and writable 1415** (in other words, if files can be added, removed, and renamed within 1416** the directory). 1417** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1418** [temp_store_directory pragma], though this could change in a future 1419** release of SQLite. 1420** With SQLITE_ACCESS_READ, the xAccess method 1421** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1422** currently unused, though it might be used in a future release of 1423** SQLite. 1424*/ 1425#define SQLITE_ACCESS_EXISTS 0 1426#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1427#define SQLITE_ACCESS_READ 2 /* Unused */ 1428 1429/* 1430** CAPI3REF: Flags for the xShmLock VFS method 1431** 1432** These integer constants define the various locking operations 1433** allowed by the xShmLock method of [sqlite3_io_methods]. The 1434** following are the only legal combinations of flags to the 1435** xShmLock method: 1436** 1437** <ul> 1438** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1439** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1440** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1441** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1442** </ul> 1443** 1444** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1445** was given on the corresponding lock. 1446** 1447** The xShmLock method can transition between unlocked and SHARED or 1448** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1449** and EXCLUSIVE. 1450*/ 1451#define SQLITE_SHM_UNLOCK 1 1452#define SQLITE_SHM_LOCK 2 1453#define SQLITE_SHM_SHARED 4 1454#define SQLITE_SHM_EXCLUSIVE 8 1455 1456/* 1457** CAPI3REF: Maximum xShmLock index 1458** 1459** The xShmLock method on [sqlite3_io_methods] may use values 1460** between 0 and this upper bound as its "offset" argument. 1461** The SQLite core will never attempt to acquire or release a 1462** lock outside of this range 1463*/ 1464#define SQLITE_SHM_NLOCK 8 1465 1466 1467/* 1468** CAPI3REF: Initialize The SQLite Library 1469** 1470** ^The sqlite3_initialize() routine initializes the 1471** SQLite library. ^The sqlite3_shutdown() routine 1472** deallocates any resources that were allocated by sqlite3_initialize(). 1473** These routines are designed to aid in process initialization and 1474** shutdown on embedded systems. Workstation applications using 1475** SQLite normally do not need to invoke either of these routines. 1476** 1477** A call to sqlite3_initialize() is an "effective" call if it is 1478** the first time sqlite3_initialize() is invoked during the lifetime of 1479** the process, or if it is the first time sqlite3_initialize() is invoked 1480** following a call to sqlite3_shutdown(). ^(Only an effective call 1481** of sqlite3_initialize() does any initialization. All other calls 1482** are harmless no-ops.)^ 1483** 1484** A call to sqlite3_shutdown() is an "effective" call if it is the first 1485** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1486** an effective call to sqlite3_shutdown() does any deinitialization. 1487** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1488** 1489** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1490** is not. The sqlite3_shutdown() interface must only be called from a 1491** single thread. All open [database connections] must be closed and all 1492** other SQLite resources must be deallocated prior to invoking 1493** sqlite3_shutdown(). 1494** 1495** Among other things, ^sqlite3_initialize() will invoke 1496** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1497** will invoke sqlite3_os_end(). 1498** 1499** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1500** ^If for some reason, sqlite3_initialize() is unable to initialize 1501** the library (perhaps it is unable to allocate a needed resource such 1502** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1503** 1504** ^The sqlite3_initialize() routine is called internally by many other 1505** SQLite interfaces so that an application usually does not need to 1506** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1507** calls sqlite3_initialize() so the SQLite library will be automatically 1508** initialized when [sqlite3_open()] is called if it has not be initialized 1509** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1510** compile-time option, then the automatic calls to sqlite3_initialize() 1511** are omitted and the application must call sqlite3_initialize() directly 1512** prior to using any other SQLite interface. For maximum portability, 1513** it is recommended that applications always invoke sqlite3_initialize() 1514** directly prior to using any other SQLite interface. Future releases 1515** of SQLite may require this. In other words, the behavior exhibited 1516** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1517** default behavior in some future release of SQLite. 1518** 1519** The sqlite3_os_init() routine does operating-system specific 1520** initialization of the SQLite library. The sqlite3_os_end() 1521** routine undoes the effect of sqlite3_os_init(). Typical tasks 1522** performed by these routines include allocation or deallocation 1523** of static resources, initialization of global variables, 1524** setting up a default [sqlite3_vfs] module, or setting up 1525** a default configuration using [sqlite3_config()]. 1526** 1527** The application should never invoke either sqlite3_os_init() 1528** or sqlite3_os_end() directly. The application should only invoke 1529** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1530** interface is called automatically by sqlite3_initialize() and 1531** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1532** implementations for sqlite3_os_init() and sqlite3_os_end() 1533** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1534** When [custom builds | built for other platforms] 1535** (using the [SQLITE_OS_OTHER=1] compile-time 1536** option) the application must supply a suitable implementation for 1537** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1538** implementation of sqlite3_os_init() or sqlite3_os_end() 1539** must return [SQLITE_OK] on success and some other [error code] upon 1540** failure. 1541*/ 1542int sqlite3_initialize(void); 1543int sqlite3_shutdown(void); 1544int sqlite3_os_init(void); 1545int sqlite3_os_end(void); 1546 1547/* 1548** CAPI3REF: Configuring The SQLite Library 1549** 1550** The sqlite3_config() interface is used to make global configuration 1551** changes to SQLite in order to tune SQLite to the specific needs of 1552** the application. The default configuration is recommended for most 1553** applications and so this routine is usually not necessary. It is 1554** provided to support rare applications with unusual needs. 1555** 1556** <b>The sqlite3_config() interface is not threadsafe. The application 1557** must ensure that no other SQLite interfaces are invoked by other 1558** threads while sqlite3_config() is running.</b> 1559** 1560** The sqlite3_config() interface 1561** may only be invoked prior to library initialization using 1562** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1563** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1564** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1565** Note, however, that ^sqlite3_config() can be called as part of the 1566** implementation of an application-defined [sqlite3_os_init()]. 1567** 1568** The first argument to sqlite3_config() is an integer 1569** [configuration option] that determines 1570** what property of SQLite is to be configured. Subsequent arguments 1571** vary depending on the [configuration option] 1572** in the first argument. 1573** 1574** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1575** ^If the option is unknown or SQLite is unable to set the option 1576** then this routine returns a non-zero [error code]. 1577*/ 1578int sqlite3_config(int, ...); 1579 1580/* 1581** CAPI3REF: Configure database connections 1582** METHOD: sqlite3 1583** 1584** The sqlite3_db_config() interface is used to make configuration 1585** changes to a [database connection]. The interface is similar to 1586** [sqlite3_config()] except that the changes apply to a single 1587** [database connection] (specified in the first argument). 1588** 1589** The second argument to sqlite3_db_config(D,V,...) is the 1590** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1591** that indicates what aspect of the [database connection] is being configured. 1592** Subsequent arguments vary depending on the configuration verb. 1593** 1594** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1595** the call is considered successful. 1596*/ 1597int sqlite3_db_config(sqlite3*, int op, ...); 1598 1599/* 1600** CAPI3REF: Memory Allocation Routines 1601** 1602** An instance of this object defines the interface between SQLite 1603** and low-level memory allocation routines. 1604** 1605** This object is used in only one place in the SQLite interface. 1606** A pointer to an instance of this object is the argument to 1607** [sqlite3_config()] when the configuration option is 1608** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1609** By creating an instance of this object 1610** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1611** during configuration, an application can specify an alternative 1612** memory allocation subsystem for SQLite to use for all of its 1613** dynamic memory needs. 1614** 1615** Note that SQLite comes with several [built-in memory allocators] 1616** that are perfectly adequate for the overwhelming majority of applications 1617** and that this object is only useful to a tiny minority of applications 1618** with specialized memory allocation requirements. This object is 1619** also used during testing of SQLite in order to specify an alternative 1620** memory allocator that simulates memory out-of-memory conditions in 1621** order to verify that SQLite recovers gracefully from such 1622** conditions. 1623** 1624** The xMalloc, xRealloc, and xFree methods must work like the 1625** malloc(), realloc() and free() functions from the standard C library. 1626** ^SQLite guarantees that the second argument to 1627** xRealloc is always a value returned by a prior call to xRoundup. 1628** 1629** xSize should return the allocated size of a memory allocation 1630** previously obtained from xMalloc or xRealloc. The allocated size 1631** is always at least as big as the requested size but may be larger. 1632** 1633** The xRoundup method returns what would be the allocated size of 1634** a memory allocation given a particular requested size. Most memory 1635** allocators round up memory allocations at least to the next multiple 1636** of 8. Some allocators round up to a larger multiple or to a power of 2. 1637** Every memory allocation request coming in through [sqlite3_malloc()] 1638** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1639** that causes the corresponding memory allocation to fail. 1640** 1641** The xInit method initializes the memory allocator. For example, 1642** it might allocate any required mutexes or initialize internal data 1643** structures. The xShutdown method is invoked (indirectly) by 1644** [sqlite3_shutdown()] and should deallocate any resources acquired 1645** by xInit. The pAppData pointer is used as the only parameter to 1646** xInit and xShutdown. 1647** 1648** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1649** the xInit method, so the xInit method need not be threadsafe. The 1650** xShutdown method is only called from [sqlite3_shutdown()] so it does 1651** not need to be threadsafe either. For all other methods, SQLite 1652** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1653** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1654** it is by default) and so the methods are automatically serialized. 1655** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1656** methods must be threadsafe or else make their own arrangements for 1657** serialization. 1658** 1659** SQLite will never invoke xInit() more than once without an intervening 1660** call to xShutdown(). 1661*/ 1662typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1663struct sqlite3_mem_methods { 1664 void *(*xMalloc)(int); /* Memory allocation function */ 1665 void (*xFree)(void*); /* Free a prior allocation */ 1666 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1667 int (*xSize)(void*); /* Return the size of an allocation */ 1668 int (*xRoundup)(int); /* Round up request size to allocation size */ 1669 int (*xInit)(void*); /* Initialize the memory allocator */ 1670 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1671 void *pAppData; /* Argument to xInit() and xShutdown() */ 1672}; 1673 1674/* 1675** CAPI3REF: Configuration Options 1676** KEYWORDS: {configuration option} 1677** 1678** These constants are the available integer configuration options that 1679** can be passed as the first argument to the [sqlite3_config()] interface. 1680** 1681** New configuration options may be added in future releases of SQLite. 1682** Existing configuration options might be discontinued. Applications 1683** should check the return code from [sqlite3_config()] to make sure that 1684** the call worked. The [sqlite3_config()] interface will return a 1685** non-zero [error code] if a discontinued or unsupported configuration option 1686** is invoked. 1687** 1688** <dl> 1689** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1690** <dd>There are no arguments to this option. ^This option sets the 1691** [threading mode] to Single-thread. In other words, it disables 1692** all mutexing and puts SQLite into a mode where it can only be used 1693** by a single thread. ^If SQLite is compiled with 1694** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1695** it is not possible to change the [threading mode] from its default 1696** value of Single-thread and so [sqlite3_config()] will return 1697** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1698** configuration option.</dd> 1699** 1700** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1701** <dd>There are no arguments to this option. ^This option sets the 1702** [threading mode] to Multi-thread. In other words, it disables 1703** mutexing on [database connection] and [prepared statement] objects. 1704** The application is responsible for serializing access to 1705** [database connections] and [prepared statements]. But other mutexes 1706** are enabled so that SQLite will be safe to use in a multi-threaded 1707** environment as long as no two threads attempt to use the same 1708** [database connection] at the same time. ^If SQLite is compiled with 1709** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1710** it is not possible to set the Multi-thread [threading mode] and 1711** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1712** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1713** 1714** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1715** <dd>There are no arguments to this option. ^This option sets the 1716** [threading mode] to Serialized. In other words, this option enables 1717** all mutexes including the recursive 1718** mutexes on [database connection] and [prepared statement] objects. 1719** In this mode (which is the default when SQLite is compiled with 1720** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1721** to [database connections] and [prepared statements] so that the 1722** application is free to use the same [database connection] or the 1723** same [prepared statement] in different threads at the same time. 1724** ^If SQLite is compiled with 1725** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1726** it is not possible to set the Serialized [threading mode] and 1727** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1728** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1729** 1730** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1731** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1732** a pointer to an instance of the [sqlite3_mem_methods] structure. 1733** The argument specifies 1734** alternative low-level memory allocation routines to be used in place of 1735** the memory allocation routines built into SQLite.)^ ^SQLite makes 1736** its own private copy of the content of the [sqlite3_mem_methods] structure 1737** before the [sqlite3_config()] call returns.</dd> 1738** 1739** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1740** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1741** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1742** The [sqlite3_mem_methods] 1743** structure is filled with the currently defined memory allocation routines.)^ 1744** This option can be used to overload the default memory allocation 1745** routines with a wrapper that simulations memory allocation failure or 1746** tracks memory usage, for example. </dd> 1747** 1748** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1749** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1750** type int, interpreted as a boolean, which if true provides a hint to 1751** SQLite that it should avoid large memory allocations if possible. 1752** SQLite will run faster if it is free to make large memory allocations, 1753** but some application might prefer to run slower in exchange for 1754** guarantees about memory fragmentation that are possible if large 1755** allocations are avoided. This hint is normally off. 1756** </dd> 1757** 1758** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1759** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1760** interpreted as a boolean, which enables or disables the collection of 1761** memory allocation statistics. ^(When memory allocation statistics are 1762** disabled, the following SQLite interfaces become non-operational: 1763** <ul> 1764** <li> [sqlite3_hard_heap_limit64()] 1765** <li> [sqlite3_memory_used()] 1766** <li> [sqlite3_memory_highwater()] 1767** <li> [sqlite3_soft_heap_limit64()] 1768** <li> [sqlite3_status64()] 1769** </ul>)^ 1770** ^Memory allocation statistics are enabled by default unless SQLite is 1771** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1772** allocation statistics are disabled by default. 1773** </dd> 1774** 1775** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1776** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1777** </dd> 1778** 1779** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1780** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1781** that SQLite can use for the database page cache with the default page 1782** cache implementation. 1783** This configuration option is a no-op if an application-defined page 1784** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1785** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1786** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1787** and the number of cache lines (N). 1788** The sz argument should be the size of the largest database page 1789** (a power of two between 512 and 65536) plus some extra bytes for each 1790** page header. ^The number of extra bytes needed by the page header 1791** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1792** ^It is harmless, apart from the wasted memory, 1793** for the sz parameter to be larger than necessary. The pMem 1794** argument must be either a NULL pointer or a pointer to an 8-byte 1795** aligned block of memory of at least sz*N bytes, otherwise 1796** subsequent behavior is undefined. 1797** ^When pMem is not NULL, SQLite will strive to use the memory provided 1798** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1799** a page cache line is larger than sz bytes or if all of the pMem buffer 1800** is exhausted. 1801** ^If pMem is NULL and N is non-zero, then each database connection 1802** does an initial bulk allocation for page cache memory 1803** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1804** of -1024*N bytes if N is negative, . ^If additional 1805** page cache memory is needed beyond what is provided by the initial 1806** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1807** additional cache line. </dd> 1808** 1809** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1810** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1811** that SQLite will use for all of its dynamic memory allocation needs 1812** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1813** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1814** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1815** [SQLITE_ERROR] if invoked otherwise. 1816** ^There are three arguments to SQLITE_CONFIG_HEAP: 1817** An 8-byte aligned pointer to the memory, 1818** the number of bytes in the memory buffer, and the minimum allocation size. 1819** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1820** to using its default memory allocator (the system malloc() implementation), 1821** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1822** memory pointer is not NULL then the alternative memory 1823** allocator is engaged to handle all of SQLites memory allocation needs. 1824** The first pointer (the memory pointer) must be aligned to an 8-byte 1825** boundary or subsequent behavior of SQLite will be undefined. 1826** The minimum allocation size is capped at 2**12. Reasonable values 1827** for the minimum allocation size are 2**5 through 2**8.</dd> 1828** 1829** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1830** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1831** pointer to an instance of the [sqlite3_mutex_methods] structure. 1832** The argument specifies alternative low-level mutex routines to be used 1833** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1834** the content of the [sqlite3_mutex_methods] structure before the call to 1835** [sqlite3_config()] returns. ^If SQLite is compiled with 1836** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1837** the entire mutexing subsystem is omitted from the build and hence calls to 1838** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1839** return [SQLITE_ERROR].</dd> 1840** 1841** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1842** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1843** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1844** [sqlite3_mutex_methods] 1845** structure is filled with the currently defined mutex routines.)^ 1846** This option can be used to overload the default mutex allocation 1847** routines with a wrapper used to track mutex usage for performance 1848** profiling or testing, for example. ^If SQLite is compiled with 1849** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1850** the entire mutexing subsystem is omitted from the build and hence calls to 1851** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1852** return [SQLITE_ERROR].</dd> 1853** 1854** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1855** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1856** the default size of lookaside memory on each [database connection]. 1857** The first argument is the 1858** size of each lookaside buffer slot and the second is the number of 1859** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1860** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1861** option to [sqlite3_db_config()] can be used to change the lookaside 1862** configuration on individual connections.)^ </dd> 1863** 1864** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1865** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1866** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1867** the interface to a custom page cache implementation.)^ 1868** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1869** 1870** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1871** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1872** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1873** the current page cache implementation into that object.)^ </dd> 1874** 1875** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1876** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1877** global [error log]. 1878** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1879** function with a call signature of void(*)(void*,int,const char*), 1880** and a pointer to void. ^If the function pointer is not NULL, it is 1881** invoked by [sqlite3_log()] to process each logging event. ^If the 1882** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1883** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1884** passed through as the first parameter to the application-defined logger 1885** function whenever that function is invoked. ^The second parameter to 1886** the logger function is a copy of the first parameter to the corresponding 1887** [sqlite3_log()] call and is intended to be a [result code] or an 1888** [extended result code]. ^The third parameter passed to the logger is 1889** log message after formatting via [sqlite3_snprintf()]. 1890** The SQLite logging interface is not reentrant; the logger function 1891** supplied by the application must not invoke any SQLite interface. 1892** In a multi-threaded application, the application-defined logger 1893** function must be threadsafe. </dd> 1894** 1895** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1896** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1897** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1898** then URI handling is globally disabled.)^ ^If URI handling is globally 1899** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1900** [sqlite3_open16()] or 1901** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1902** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1903** connection is opened. ^If it is globally disabled, filenames are 1904** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1905** database connection is opened. ^(By default, URI handling is globally 1906** disabled. The default value may be changed by compiling with the 1907** [SQLITE_USE_URI] symbol defined.)^ 1908** 1909** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1910** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1911** argument which is interpreted as a boolean in order to enable or disable 1912** the use of covering indices for full table scans in the query optimizer. 1913** ^The default setting is determined 1914** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1915** if that compile-time option is omitted. 1916** The ability to disable the use of covering indices for full table scans 1917** is because some incorrectly coded legacy applications might malfunction 1918** when the optimization is enabled. Providing the ability to 1919** disable the optimization allows the older, buggy application code to work 1920** without change even with newer versions of SQLite. 1921** 1922** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1923** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1924** <dd> These options are obsolete and should not be used by new code. 1925** They are retained for backwards compatibility but are now no-ops. 1926** </dd> 1927** 1928** [[SQLITE_CONFIG_SQLLOG]] 1929** <dt>SQLITE_CONFIG_SQLLOG 1930** <dd>This option is only available if sqlite is compiled with the 1931** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1932** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1933** The second should be of type (void*). The callback is invoked by the library 1934** in three separate circumstances, identified by the value passed as the 1935** fourth parameter. If the fourth parameter is 0, then the database connection 1936** passed as the second argument has just been opened. The third argument 1937** points to a buffer containing the name of the main database file. If the 1938** fourth parameter is 1, then the SQL statement that the third parameter 1939** points to has just been executed. Or, if the fourth parameter is 2, then 1940** the connection being passed as the second parameter is being closed. The 1941** third parameter is passed NULL In this case. An example of using this 1942** configuration option can be seen in the "test_sqllog.c" source file in 1943** the canonical SQLite source tree.</dd> 1944** 1945** [[SQLITE_CONFIG_MMAP_SIZE]] 1946** <dt>SQLITE_CONFIG_MMAP_SIZE 1947** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1948** that are the default mmap size limit (the default setting for 1949** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1950** ^The default setting can be overridden by each database connection using 1951** either the [PRAGMA mmap_size] command, or by using the 1952** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1953** will be silently truncated if necessary so that it does not exceed the 1954** compile-time maximum mmap size set by the 1955** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1956** ^If either argument to this option is negative, then that argument is 1957** changed to its compile-time default. 1958** 1959** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1960** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1961** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1962** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1963** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1964** that specifies the maximum size of the created heap. 1965** 1966** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1967** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1968** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1969** is a pointer to an integer and writes into that integer the number of extra 1970** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1971** The amount of extra space required can change depending on the compiler, 1972** target platform, and SQLite version. 1973** 1974** [[SQLITE_CONFIG_PMASZ]] 1975** <dt>SQLITE_CONFIG_PMASZ 1976** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1977** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1978** sorter to that integer. The default minimum PMA Size is set by the 1979** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1980** to help with sort operations when multithreaded sorting 1981** is enabled (using the [PRAGMA threads] command) and the amount of content 1982** to be sorted exceeds the page size times the minimum of the 1983** [PRAGMA cache_size] setting and this value. 1984** 1985** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1986** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1987** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1988** becomes the [statement journal] spill-to-disk threshold. 1989** [Statement journals] are held in memory until their size (in bytes) 1990** exceeds this threshold, at which point they are written to disk. 1991** Or if the threshold is -1, statement journals are always held 1992** exclusively in memory. 1993** Since many statement journals never become large, setting the spill 1994** threshold to a value such as 64KiB can greatly reduce the amount of 1995** I/O required to support statement rollback. 1996** The default value for this setting is controlled by the 1997** [SQLITE_STMTJRNL_SPILL] compile-time option. 1998** 1999** [[SQLITE_CONFIG_SORTERREF_SIZE]] 2000** <dt>SQLITE_CONFIG_SORTERREF_SIZE 2001** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter 2002** of type (int) - the new value of the sorter-reference size threshold. 2003** Usually, when SQLite uses an external sort to order records according 2004** to an ORDER BY clause, all fields required by the caller are present in the 2005** sorted records. However, if SQLite determines based on the declared type 2006** of a table column that its values are likely to be very large - larger 2007** than the configured sorter-reference size threshold - then a reference 2008** is stored in each sorted record and the required column values loaded 2009** from the database as records are returned in sorted order. The default 2010** value for this option is to never use this optimization. Specifying a 2011** negative value for this option restores the default behaviour. 2012** This option is only available if SQLite is compiled with the 2013** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option. 2014** 2015** [[SQLITE_CONFIG_MEMDB_MAXSIZE]] 2016** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE 2017** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter 2018** [sqlite3_int64] parameter which is the default maximum size for an in-memory 2019** database created using [sqlite3_deserialize()]. This default maximum 2020** size can be adjusted up or down for individual databases using the 2021** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control]. If this 2022** configuration setting is never used, then the default maximum is determined 2023** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option. If that 2024** compile-time option is not set, then the default maximum is 1073741824. 2025** </dl> 2026*/ 2027#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 2028#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 2029#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 2030#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 2031#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 2032#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 2033#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 2034#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 2035#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 2036#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 2037#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 2038/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 2039#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 2040#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 2041#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 2042#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 2043#define SQLITE_CONFIG_URI 17 /* int */ 2044#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 2045#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 2046#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 2047#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 2048#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 2049#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 2050#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 2051#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 2052#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 2053#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 2054#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */ 2055#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */ 2056 2057/* 2058** CAPI3REF: Database Connection Configuration Options 2059** 2060** These constants are the available integer configuration options that 2061** can be passed as the second argument to the [sqlite3_db_config()] interface. 2062** 2063** New configuration options may be added in future releases of SQLite. 2064** Existing configuration options might be discontinued. Applications 2065** should check the return code from [sqlite3_db_config()] to make sure that 2066** the call worked. ^The [sqlite3_db_config()] interface will return a 2067** non-zero [error code] if a discontinued or unsupported configuration option 2068** is invoked. 2069** 2070** <dl> 2071** [[SQLITE_DBCONFIG_LOOKASIDE]] 2072** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 2073** <dd> ^This option takes three additional arguments that determine the 2074** [lookaside memory allocator] configuration for the [database connection]. 2075** ^The first argument (the third parameter to [sqlite3_db_config()] is a 2076** pointer to a memory buffer to use for lookaside memory. 2077** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 2078** may be NULL in which case SQLite will allocate the 2079** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 2080** size of each lookaside buffer slot. ^The third argument is the number of 2081** slots. The size of the buffer in the first argument must be greater than 2082** or equal to the product of the second and third arguments. The buffer 2083** must be aligned to an 8-byte boundary. ^If the second argument to 2084** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 2085** rounded down to the next smaller multiple of 8. ^(The lookaside memory 2086** configuration for a database connection can only be changed when that 2087** connection is not currently using lookaside memory, or in other words 2088** when the "current value" returned by 2089** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 2090** Any attempt to change the lookaside memory configuration when lookaside 2091** memory is in use leaves the configuration unchanged and returns 2092** [SQLITE_BUSY].)^</dd> 2093** 2094** [[SQLITE_DBCONFIG_ENABLE_FKEY]] 2095** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 2096** <dd> ^This option is used to enable or disable the enforcement of 2097** [foreign key constraints]. There should be two additional arguments. 2098** The first argument is an integer which is 0 to disable FK enforcement, 2099** positive to enable FK enforcement or negative to leave FK enforcement 2100** unchanged. The second parameter is a pointer to an integer into which 2101** is written 0 or 1 to indicate whether FK enforcement is off or on 2102** following this call. The second parameter may be a NULL pointer, in 2103** which case the FK enforcement setting is not reported back. </dd> 2104** 2105** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]] 2106** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2107** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2108** There should be two additional arguments. 2109** The first argument is an integer which is 0 to disable triggers, 2110** positive to enable triggers or negative to leave the setting unchanged. 2111** The second parameter is a pointer to an integer into which 2112** is written 0 or 1 to indicate whether triggers are disabled or enabled 2113** following this call. The second parameter may be a NULL pointer, in 2114** which case the trigger setting is not reported back. </dd> 2115** 2116** [[SQLITE_DBCONFIG_ENABLE_VIEW]] 2117** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt> 2118** <dd> ^This option is used to enable or disable [CREATE VIEW | views]. 2119** There should be two additional arguments. 2120** The first argument is an integer which is 0 to disable views, 2121** positive to enable views or negative to leave the setting unchanged. 2122** The second parameter is a pointer to an integer into which 2123** is written 0 or 1 to indicate whether views are disabled or enabled 2124** following this call. The second parameter may be a NULL pointer, in 2125** which case the view setting is not reported back. </dd> 2126** 2127** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]] 2128** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2129** <dd> ^This option is used to enable or disable the 2130** [fts3_tokenizer()] function which is part of the 2131** [FTS3] full-text search engine extension. 2132** There should be two additional arguments. 2133** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2134** positive to enable fts3_tokenizer() or negative to leave the setting 2135** unchanged. 2136** The second parameter is a pointer to an integer into which 2137** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2138** following this call. The second parameter may be a NULL pointer, in 2139** which case the new setting is not reported back. </dd> 2140** 2141** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]] 2142** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2143** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2144** interface independently of the [load_extension()] SQL function. 2145** The [sqlite3_enable_load_extension()] API enables or disables both the 2146** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2147** There should be two additional arguments. 2148** When the first argument to this interface is 1, then only the C-API is 2149** enabled and the SQL function remains disabled. If the first argument to 2150** this interface is 0, then both the C-API and the SQL function are disabled. 2151** If the first argument is -1, then no changes are made to state of either the 2152** C-API or the SQL function. 2153** The second parameter is a pointer to an integer into which 2154** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2155** is disabled or enabled following this call. The second parameter may 2156** be a NULL pointer, in which case the new setting is not reported back. 2157** </dd> 2158** 2159** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2160** <dd> ^This option is used to change the name of the "main" database 2161** schema. ^The sole argument is a pointer to a constant UTF8 string 2162** which will become the new schema name in place of "main". ^SQLite 2163** does not make a copy of the new main schema name string, so the application 2164** must ensure that the argument passed into this DBCONFIG option is unchanged 2165** until after the database connection closes. 2166** </dd> 2167** 2168** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]] 2169** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2170** <dd> Usually, when a database in wal mode is closed or detached from a 2171** database handle, SQLite checks if this will mean that there are now no 2172** connections at all to the database. If so, it performs a checkpoint 2173** operation before closing the connection. This option may be used to 2174** override this behaviour. The first parameter passed to this operation 2175** is an integer - positive to disable checkpoints-on-close, or zero (the 2176** default) to enable them, and negative to leave the setting unchanged. 2177** The second parameter is a pointer to an integer 2178** into which is written 0 or 1 to indicate whether checkpoints-on-close 2179** have been disabled - 0 if they are not disabled, 1 if they are. 2180** </dd> 2181** 2182** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2183** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2184** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2185** a single SQL query statement will always use the same algorithm regardless 2186** of values of [bound parameters].)^ The QPSG disables some query optimizations 2187** that look at the values of bound parameters, which can make some queries 2188** slower. But the QPSG has the advantage of more predictable behavior. With 2189** the QPSG active, SQLite will always use the same query plan in the field as 2190** was used during testing in the lab. 2191** The first argument to this setting is an integer which is 0 to disable 2192** the QPSG, positive to enable QPSG, or negative to leave the setting 2193** unchanged. The second parameter is a pointer to an integer into which 2194** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2195** following this call. 2196** </dd> 2197** 2198** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2199** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2200** include output for any operations performed by trigger programs. This 2201** option is used to set or clear (the default) a flag that governs this 2202** behavior. The first parameter passed to this operation is an integer - 2203** positive to enable output for trigger programs, or zero to disable it, 2204** or negative to leave the setting unchanged. 2205** The second parameter is a pointer to an integer into which is written 2206** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2207** it is not disabled, 1 if it is. 2208** </dd> 2209** 2210** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt> 2211** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run 2212** [VACUUM] in order to reset a database back to an empty database 2213** with no schema and no content. The following process works even for 2214** a badly corrupted database file: 2215** <ol> 2216** <li> If the database connection is newly opened, make sure it has read the 2217** database schema by preparing then discarding some query against the 2218** database, or calling sqlite3_table_column_metadata(), ignoring any 2219** errors. This step is only necessary if the application desires to keep 2220** the database in WAL mode after the reset if it was in WAL mode before 2221** the reset. 2222** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0); 2223** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0); 2224** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0); 2225** </ol> 2226** Because resetting a database is destructive and irreversible, the 2227** process requires the use of this obscure API and multiple steps to help 2228** ensure that it does not happen by accident. 2229** 2230** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt> 2231** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the 2232** "defensive" flag for a database connection. When the defensive 2233** flag is enabled, language features that allow ordinary SQL to 2234** deliberately corrupt the database file are disabled. The disabled 2235** features include but are not limited to the following: 2236** <ul> 2237** <li> The [PRAGMA writable_schema=ON] statement. 2238** <li> The [PRAGMA journal_mode=OFF] statement. 2239** <li> Writes to the [sqlite_dbpage] virtual table. 2240** <li> Direct writes to [shadow tables]. 2241** </ul> 2242** </dd> 2243** 2244** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt> 2245** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the 2246** "writable_schema" flag. This has the same effect and is logically equivalent 2247** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF]. 2248** The first argument to this setting is an integer which is 0 to disable 2249** the writable_schema, positive to enable writable_schema, or negative to 2250** leave the setting unchanged. The second parameter is a pointer to an 2251** integer into which is written 0 or 1 to indicate whether the writable_schema 2252** is enabled or disabled following this call. 2253** </dd> 2254** 2255** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]] 2256** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt> 2257** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates 2258** the legacy behavior of the [ALTER TABLE RENAME] command such it 2259** behaves as it did prior to [version 3.24.0] (2018-06-04). See the 2260** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for 2261** additional information. This feature can also be turned on and off 2262** using the [PRAGMA legacy_alter_table] statement. 2263** </dd> 2264** 2265** [[SQLITE_DBCONFIG_DQS_DML]] 2266** <dt>SQLITE_DBCONFIG_DQS_DML</td> 2267** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates 2268** the legacy [double-quoted string literal] misfeature for DML statements 2269** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The 2270** default value of this setting is determined by the [-DSQLITE_DQS] 2271** compile-time option. 2272** </dd> 2273** 2274** [[SQLITE_DBCONFIG_DQS_DDL]] 2275** <dt>SQLITE_DBCONFIG_DQS_DDL</td> 2276** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates 2277** the legacy [double-quoted string literal] misfeature for DDL statements, 2278** such as CREATE TABLE and CREATE INDEX. The 2279** default value of this setting is determined by the [-DSQLITE_DQS] 2280** compile-time option. 2281** </dd> 2282** 2283** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]] 2284** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td> 2285** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to 2286** assume that database schemas (the contents of the [sqlite_master] tables) 2287** are untainted by malicious content. 2288** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite 2289** takes additional defensive steps to protect the application from harm 2290** including: 2291** <ul> 2292** <li> Prohibit the use of SQL functions inside triggers, views, 2293** CHECK constraints, DEFAULT clauses, expression indexes, 2294** partial indexes, or generated columns 2295** unless those functions are tagged with [SQLITE_INNOCUOUS]. 2296** <li> Prohibit the use of virtual tables inside of triggers or views 2297** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS]. 2298** </ul> 2299** This setting defaults to "on" for legacy compatibility, however 2300** all applications are advised to turn it off if possible. This setting 2301** can also be controlled using the [PRAGMA trusted_schema] statement. 2302** </dd> 2303** 2304** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]] 2305** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td> 2306** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates 2307** the legacy file format flag. When activated, this flag causes all newly 2308** created database file to have a schema format version number (the 4-byte 2309** integer found at offset 44 into the database header) of 1. This in turn 2310** means that the resulting database file will be readable and writable by 2311** any SQLite version back to 3.0.0 ([dateof:3.0.0]). Without this setting, 2312** newly created databases are generally not understandable by SQLite versions 2313** prior to 3.3.0 ([dateof:3.3.0]). As these words are written, there 2314** is now scarcely any need to generated database files that are compatible 2315** all the way back to version 3.0.0, and so this setting is of little 2316** practical use, but is provided so that SQLite can continue to claim the 2317** ability to generate new database files that are compatible with version 2318** 3.0.0. 2319** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on, 2320** the [VACUUM] command will fail with an obscure error when attempting to 2321** process a table with generated columns and a descending index. This is 2322** not considered a bug since SQLite versions 3.3.0 and earlier do not support 2323** either generated columns or decending indexes. 2324** </dd> 2325** </dl> 2326*/ 2327#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2328#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2329#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2330#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2331#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2332#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2333#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2334#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2335#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2336#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */ 2337#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */ 2338#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */ 2339#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */ 2340#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */ 2341#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */ 2342#define SQLITE_DBCONFIG_ENABLE_VIEW 1015 /* int int* */ 2343#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT 1016 /* int int* */ 2344#define SQLITE_DBCONFIG_TRUSTED_SCHEMA 1017 /* int int* */ 2345#define SQLITE_DBCONFIG_MAX 1017 /* Largest DBCONFIG */ 2346 2347/* 2348** CAPI3REF: Enable Or Disable Extended Result Codes 2349** METHOD: sqlite3 2350** 2351** ^The sqlite3_extended_result_codes() routine enables or disables the 2352** [extended result codes] feature of SQLite. ^The extended result 2353** codes are disabled by default for historical compatibility. 2354*/ 2355int sqlite3_extended_result_codes(sqlite3*, int onoff); 2356 2357/* 2358** CAPI3REF: Last Insert Rowid 2359** METHOD: sqlite3 2360** 2361** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2362** has a unique 64-bit signed 2363** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2364** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2365** names are not also used by explicitly declared columns. ^If 2366** the table has a column of type [INTEGER PRIMARY KEY] then that column 2367** is another alias for the rowid. 2368** 2369** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2370** the most recent successful [INSERT] into a rowid table or [virtual table] 2371** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2372** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2373** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2374** zero. 2375** 2376** As well as being set automatically as rows are inserted into database 2377** tables, the value returned by this function may be set explicitly by 2378** [sqlite3_set_last_insert_rowid()] 2379** 2380** Some virtual table implementations may INSERT rows into rowid tables as 2381** part of committing a transaction (e.g. to flush data accumulated in memory 2382** to disk). In this case subsequent calls to this function return the rowid 2383** associated with these internal INSERT operations, which leads to 2384** unintuitive results. Virtual table implementations that do write to rowid 2385** tables in this way can avoid this problem by restoring the original 2386** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2387** control to the user. 2388** 2389** ^(If an [INSERT] occurs within a trigger then this routine will 2390** return the [rowid] of the inserted row as long as the trigger is 2391** running. Once the trigger program ends, the value returned 2392** by this routine reverts to what it was before the trigger was fired.)^ 2393** 2394** ^An [INSERT] that fails due to a constraint violation is not a 2395** successful [INSERT] and does not change the value returned by this 2396** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2397** and INSERT OR ABORT make no changes to the return value of this 2398** routine when their insertion fails. ^(When INSERT OR REPLACE 2399** encounters a constraint violation, it does not fail. The 2400** INSERT continues to completion after deleting rows that caused 2401** the constraint problem so INSERT OR REPLACE will always change 2402** the return value of this interface.)^ 2403** 2404** ^For the purposes of this routine, an [INSERT] is considered to 2405** be successful even if it is subsequently rolled back. 2406** 2407** This function is accessible to SQL statements via the 2408** [last_insert_rowid() SQL function]. 2409** 2410** If a separate thread performs a new [INSERT] on the same 2411** database connection while the [sqlite3_last_insert_rowid()] 2412** function is running and thus changes the last insert [rowid], 2413** then the value returned by [sqlite3_last_insert_rowid()] is 2414** unpredictable and might not equal either the old or the new 2415** last insert [rowid]. 2416*/ 2417sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2418 2419/* 2420** CAPI3REF: Set the Last Insert Rowid value. 2421** METHOD: sqlite3 2422** 2423** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2424** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2425** without inserting a row into the database. 2426*/ 2427void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2428 2429/* 2430** CAPI3REF: Count The Number Of Rows Modified 2431** METHOD: sqlite3 2432** 2433** ^This function returns the number of rows modified, inserted or 2434** deleted by the most recently completed INSERT, UPDATE or DELETE 2435** statement on the database connection specified by the only parameter. 2436** ^Executing any other type of SQL statement does not modify the value 2437** returned by this function. 2438** 2439** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2440** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2441** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2442** 2443** Changes to a view that are intercepted by 2444** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2445** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2446** DELETE statement run on a view is always zero. Only changes made to real 2447** tables are counted. 2448** 2449** Things are more complicated if the sqlite3_changes() function is 2450** executed while a trigger program is running. This may happen if the 2451** program uses the [changes() SQL function], or if some other callback 2452** function invokes sqlite3_changes() directly. Essentially: 2453** 2454** <ul> 2455** <li> ^(Before entering a trigger program the value returned by 2456** sqlite3_changes() function is saved. After the trigger program 2457** has finished, the original value is restored.)^ 2458** 2459** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2460** statement sets the value returned by sqlite3_changes() 2461** upon completion as normal. Of course, this value will not include 2462** any changes performed by sub-triggers, as the sqlite3_changes() 2463** value will be saved and restored after each sub-trigger has run.)^ 2464** </ul> 2465** 2466** ^This means that if the changes() SQL function (or similar) is used 2467** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2468** returns the value as set when the calling statement began executing. 2469** ^If it is used by the second or subsequent such statement within a trigger 2470** program, the value returned reflects the number of rows modified by the 2471** previous INSERT, UPDATE or DELETE statement within the same trigger. 2472** 2473** If a separate thread makes changes on the same database connection 2474** while [sqlite3_changes()] is running then the value returned 2475** is unpredictable and not meaningful. 2476** 2477** See also: 2478** <ul> 2479** <li> the [sqlite3_total_changes()] interface 2480** <li> the [count_changes pragma] 2481** <li> the [changes() SQL function] 2482** <li> the [data_version pragma] 2483** </ul> 2484*/ 2485int sqlite3_changes(sqlite3*); 2486 2487/* 2488** CAPI3REF: Total Number Of Rows Modified 2489** METHOD: sqlite3 2490** 2491** ^This function returns the total number of rows inserted, modified or 2492** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2493** since the database connection was opened, including those executed as 2494** part of trigger programs. ^Executing any other type of SQL statement 2495** does not affect the value returned by sqlite3_total_changes(). 2496** 2497** ^Changes made as part of [foreign key actions] are included in the 2498** count, but those made as part of REPLACE constraint resolution are 2499** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2500** are not counted. 2501** 2502** The [sqlite3_total_changes(D)] interface only reports the number 2503** of rows that changed due to SQL statement run against database 2504** connection D. Any changes by other database connections are ignored. 2505** To detect changes against a database file from other database 2506** connections use the [PRAGMA data_version] command or the 2507** [SQLITE_FCNTL_DATA_VERSION] [file control]. 2508** 2509** If a separate thread makes changes on the same database connection 2510** while [sqlite3_total_changes()] is running then the value 2511** returned is unpredictable and not meaningful. 2512** 2513** See also: 2514** <ul> 2515** <li> the [sqlite3_changes()] interface 2516** <li> the [count_changes pragma] 2517** <li> the [changes() SQL function] 2518** <li> the [data_version pragma] 2519** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control] 2520** </ul> 2521*/ 2522int sqlite3_total_changes(sqlite3*); 2523 2524/* 2525** CAPI3REF: Interrupt A Long-Running Query 2526** METHOD: sqlite3 2527** 2528** ^This function causes any pending database operation to abort and 2529** return at its earliest opportunity. This routine is typically 2530** called in response to a user action such as pressing "Cancel" 2531** or Ctrl-C where the user wants a long query operation to halt 2532** immediately. 2533** 2534** ^It is safe to call this routine from a thread different from the 2535** thread that is currently running the database operation. But it 2536** is not safe to call this routine with a [database connection] that 2537** is closed or might close before sqlite3_interrupt() returns. 2538** 2539** ^If an SQL operation is very nearly finished at the time when 2540** sqlite3_interrupt() is called, then it might not have an opportunity 2541** to be interrupted and might continue to completion. 2542** 2543** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2544** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2545** that is inside an explicit transaction, then the entire transaction 2546** will be rolled back automatically. 2547** 2548** ^The sqlite3_interrupt(D) call is in effect until all currently running 2549** SQL statements on [database connection] D complete. ^Any new SQL statements 2550** that are started after the sqlite3_interrupt() call and before the 2551** running statement count reaches zero are interrupted as if they had been 2552** running prior to the sqlite3_interrupt() call. ^New SQL statements 2553** that are started after the running statement count reaches zero are 2554** not effected by the sqlite3_interrupt(). 2555** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2556** SQL statements is a no-op and has no effect on SQL statements 2557** that are started after the sqlite3_interrupt() call returns. 2558*/ 2559void sqlite3_interrupt(sqlite3*); 2560 2561/* 2562** CAPI3REF: Determine If An SQL Statement Is Complete 2563** 2564** These routines are useful during command-line input to determine if the 2565** currently entered text seems to form a complete SQL statement or 2566** if additional input is needed before sending the text into 2567** SQLite for parsing. ^These routines return 1 if the input string 2568** appears to be a complete SQL statement. ^A statement is judged to be 2569** complete if it ends with a semicolon token and is not a prefix of a 2570** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2571** string literals or quoted identifier names or comments are not 2572** independent tokens (they are part of the token in which they are 2573** embedded) and thus do not count as a statement terminator. ^Whitespace 2574** and comments that follow the final semicolon are ignored. 2575** 2576** ^These routines return 0 if the statement is incomplete. ^If a 2577** memory allocation fails, then SQLITE_NOMEM is returned. 2578** 2579** ^These routines do not parse the SQL statements thus 2580** will not detect syntactically incorrect SQL. 2581** 2582** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2583** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2584** automatically by sqlite3_complete16(). If that initialization fails, 2585** then the return value from sqlite3_complete16() will be non-zero 2586** regardless of whether or not the input SQL is complete.)^ 2587** 2588** The input to [sqlite3_complete()] must be a zero-terminated 2589** UTF-8 string. 2590** 2591** The input to [sqlite3_complete16()] must be a zero-terminated 2592** UTF-16 string in native byte order. 2593*/ 2594int sqlite3_complete(const char *sql); 2595int sqlite3_complete16(const void *sql); 2596 2597/* 2598** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2599** KEYWORDS: {busy-handler callback} {busy handler} 2600** METHOD: sqlite3 2601** 2602** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2603** that might be invoked with argument P whenever 2604** an attempt is made to access a database table associated with 2605** [database connection] D when another thread 2606** or process has the table locked. 2607** The sqlite3_busy_handler() interface is used to implement 2608** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2609** 2610** ^If the busy callback is NULL, then [SQLITE_BUSY] 2611** is returned immediately upon encountering the lock. ^If the busy callback 2612** is not NULL, then the callback might be invoked with two arguments. 2613** 2614** ^The first argument to the busy handler is a copy of the void* pointer which 2615** is the third argument to sqlite3_busy_handler(). ^The second argument to 2616** the busy handler callback is the number of times that the busy handler has 2617** been invoked previously for the same locking event. ^If the 2618** busy callback returns 0, then no additional attempts are made to 2619** access the database and [SQLITE_BUSY] is returned 2620** to the application. 2621** ^If the callback returns non-zero, then another attempt 2622** is made to access the database and the cycle repeats. 2623** 2624** The presence of a busy handler does not guarantee that it will be invoked 2625** when there is lock contention. ^If SQLite determines that invoking the busy 2626** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2627** to the application instead of invoking the 2628** busy handler. 2629** Consider a scenario where one process is holding a read lock that 2630** it is trying to promote to a reserved lock and 2631** a second process is holding a reserved lock that it is trying 2632** to promote to an exclusive lock. The first process cannot proceed 2633** because it is blocked by the second and the second process cannot 2634** proceed because it is blocked by the first. If both processes 2635** invoke the busy handlers, neither will make any progress. Therefore, 2636** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2637** will induce the first process to release its read lock and allow 2638** the second process to proceed. 2639** 2640** ^The default busy callback is NULL. 2641** 2642** ^(There can only be a single busy handler defined for each 2643** [database connection]. Setting a new busy handler clears any 2644** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2645** or evaluating [PRAGMA busy_timeout=N] will change the 2646** busy handler and thus clear any previously set busy handler. 2647** 2648** The busy callback should not take any actions which modify the 2649** database connection that invoked the busy handler. In other words, 2650** the busy handler is not reentrant. Any such actions 2651** result in undefined behavior. 2652** 2653** A busy handler must not close the database connection 2654** or [prepared statement] that invoked the busy handler. 2655*/ 2656int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2657 2658/* 2659** CAPI3REF: Set A Busy Timeout 2660** METHOD: sqlite3 2661** 2662** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2663** for a specified amount of time when a table is locked. ^The handler 2664** will sleep multiple times until at least "ms" milliseconds of sleeping 2665** have accumulated. ^After at least "ms" milliseconds of sleeping, 2666** the handler returns 0 which causes [sqlite3_step()] to return 2667** [SQLITE_BUSY]. 2668** 2669** ^Calling this routine with an argument less than or equal to zero 2670** turns off all busy handlers. 2671** 2672** ^(There can only be a single busy handler for a particular 2673** [database connection] at any given moment. If another busy handler 2674** was defined (using [sqlite3_busy_handler()]) prior to calling 2675** this routine, that other busy handler is cleared.)^ 2676** 2677** See also: [PRAGMA busy_timeout] 2678*/ 2679int sqlite3_busy_timeout(sqlite3*, int ms); 2680 2681/* 2682** CAPI3REF: Convenience Routines For Running Queries 2683** METHOD: sqlite3 2684** 2685** This is a legacy interface that is preserved for backwards compatibility. 2686** Use of this interface is not recommended. 2687** 2688** Definition: A <b>result table</b> is memory data structure created by the 2689** [sqlite3_get_table()] interface. A result table records the 2690** complete query results from one or more queries. 2691** 2692** The table conceptually has a number of rows and columns. But 2693** these numbers are not part of the result table itself. These 2694** numbers are obtained separately. Let N be the number of rows 2695** and M be the number of columns. 2696** 2697** A result table is an array of pointers to zero-terminated UTF-8 strings. 2698** There are (N+1)*M elements in the array. The first M pointers point 2699** to zero-terminated strings that contain the names of the columns. 2700** The remaining entries all point to query results. NULL values result 2701** in NULL pointers. All other values are in their UTF-8 zero-terminated 2702** string representation as returned by [sqlite3_column_text()]. 2703** 2704** A result table might consist of one or more memory allocations. 2705** It is not safe to pass a result table directly to [sqlite3_free()]. 2706** A result table should be deallocated using [sqlite3_free_table()]. 2707** 2708** ^(As an example of the result table format, suppose a query result 2709** is as follows: 2710** 2711** <blockquote><pre> 2712** Name | Age 2713** ----------------------- 2714** Alice | 43 2715** Bob | 28 2716** Cindy | 21 2717** </pre></blockquote> 2718** 2719** There are two columns (M==2) and three rows (N==3). Thus the 2720** result table has 8 entries. Suppose the result table is stored 2721** in an array named azResult. Then azResult holds this content: 2722** 2723** <blockquote><pre> 2724** azResult[0] = "Name"; 2725** azResult[1] = "Age"; 2726** azResult[2] = "Alice"; 2727** azResult[3] = "43"; 2728** azResult[4] = "Bob"; 2729** azResult[5] = "28"; 2730** azResult[6] = "Cindy"; 2731** azResult[7] = "21"; 2732** </pre></blockquote>)^ 2733** 2734** ^The sqlite3_get_table() function evaluates one or more 2735** semicolon-separated SQL statements in the zero-terminated UTF-8 2736** string of its 2nd parameter and returns a result table to the 2737** pointer given in its 3rd parameter. 2738** 2739** After the application has finished with the result from sqlite3_get_table(), 2740** it must pass the result table pointer to sqlite3_free_table() in order to 2741** release the memory that was malloced. Because of the way the 2742** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2743** function must not try to call [sqlite3_free()] directly. Only 2744** [sqlite3_free_table()] is able to release the memory properly and safely. 2745** 2746** The sqlite3_get_table() interface is implemented as a wrapper around 2747** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2748** to any internal data structures of SQLite. It uses only the public 2749** interface defined here. As a consequence, errors that occur in the 2750** wrapper layer outside of the internal [sqlite3_exec()] call are not 2751** reflected in subsequent calls to [sqlite3_errcode()] or 2752** [sqlite3_errmsg()]. 2753*/ 2754int sqlite3_get_table( 2755 sqlite3 *db, /* An open database */ 2756 const char *zSql, /* SQL to be evaluated */ 2757 char ***pazResult, /* Results of the query */ 2758 int *pnRow, /* Number of result rows written here */ 2759 int *pnColumn, /* Number of result columns written here */ 2760 char **pzErrmsg /* Error msg written here */ 2761); 2762void sqlite3_free_table(char **result); 2763 2764/* 2765** CAPI3REF: Formatted String Printing Functions 2766** 2767** These routines are work-alikes of the "printf()" family of functions 2768** from the standard C library. 2769** These routines understand most of the common formatting options from 2770** the standard library printf() 2771** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2772** See the [built-in printf()] documentation for details. 2773** 2774** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2775** results into memory obtained from [sqlite3_malloc64()]. 2776** The strings returned by these two routines should be 2777** released by [sqlite3_free()]. ^Both routines return a 2778** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2779** memory to hold the resulting string. 2780** 2781** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2782** the standard C library. The result is written into the 2783** buffer supplied as the second parameter whose size is given by 2784** the first parameter. Note that the order of the 2785** first two parameters is reversed from snprintf().)^ This is an 2786** historical accident that cannot be fixed without breaking 2787** backwards compatibility. ^(Note also that sqlite3_snprintf() 2788** returns a pointer to its buffer instead of the number of 2789** characters actually written into the buffer.)^ We admit that 2790** the number of characters written would be a more useful return 2791** value but we cannot change the implementation of sqlite3_snprintf() 2792** now without breaking compatibility. 2793** 2794** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2795** guarantees that the buffer is always zero-terminated. ^The first 2796** parameter "n" is the total size of the buffer, including space for 2797** the zero terminator. So the longest string that can be completely 2798** written will be n-1 characters. 2799** 2800** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2801** 2802** See also: [built-in printf()], [printf() SQL function] 2803*/ 2804char *sqlite3_mprintf(const char*,...); 2805char *sqlite3_vmprintf(const char*, va_list); 2806char *sqlite3_snprintf(int,char*,const char*, ...); 2807char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2808 2809/* 2810** CAPI3REF: Memory Allocation Subsystem 2811** 2812** The SQLite core uses these three routines for all of its own 2813** internal memory allocation needs. "Core" in the previous sentence 2814** does not include operating-system specific [VFS] implementation. The 2815** Windows VFS uses native malloc() and free() for some operations. 2816** 2817** ^The sqlite3_malloc() routine returns a pointer to a block 2818** of memory at least N bytes in length, where N is the parameter. 2819** ^If sqlite3_malloc() is unable to obtain sufficient free 2820** memory, it returns a NULL pointer. ^If the parameter N to 2821** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2822** a NULL pointer. 2823** 2824** ^The sqlite3_malloc64(N) routine works just like 2825** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2826** of a signed 32-bit integer. 2827** 2828** ^Calling sqlite3_free() with a pointer previously returned 2829** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2830** that it might be reused. ^The sqlite3_free() routine is 2831** a no-op if is called with a NULL pointer. Passing a NULL pointer 2832** to sqlite3_free() is harmless. After being freed, memory 2833** should neither be read nor written. Even reading previously freed 2834** memory might result in a segmentation fault or other severe error. 2835** Memory corruption, a segmentation fault, or other severe error 2836** might result if sqlite3_free() is called with a non-NULL pointer that 2837** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2838** 2839** ^The sqlite3_realloc(X,N) interface attempts to resize a 2840** prior memory allocation X to be at least N bytes. 2841** ^If the X parameter to sqlite3_realloc(X,N) 2842** is a NULL pointer then its behavior is identical to calling 2843** sqlite3_malloc(N). 2844** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2845** negative then the behavior is exactly the same as calling 2846** sqlite3_free(X). 2847** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2848** of at least N bytes in size or NULL if insufficient memory is available. 2849** ^If M is the size of the prior allocation, then min(N,M) bytes 2850** of the prior allocation are copied into the beginning of buffer returned 2851** by sqlite3_realloc(X,N) and the prior allocation is freed. 2852** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2853** prior allocation is not freed. 2854** 2855** ^The sqlite3_realloc64(X,N) interfaces works the same as 2856** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2857** of a 32-bit signed integer. 2858** 2859** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2860** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2861** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2862** ^The value returned by sqlite3_msize(X) might be larger than the number 2863** of bytes requested when X was allocated. ^If X is a NULL pointer then 2864** sqlite3_msize(X) returns zero. If X points to something that is not 2865** the beginning of memory allocation, or if it points to a formerly 2866** valid memory allocation that has now been freed, then the behavior 2867** of sqlite3_msize(X) is undefined and possibly harmful. 2868** 2869** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2870** sqlite3_malloc64(), and sqlite3_realloc64() 2871** is always aligned to at least an 8 byte boundary, or to a 2872** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2873** option is used. 2874** 2875** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2876** must be either NULL or else pointers obtained from a prior 2877** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2878** not yet been released. 2879** 2880** The application must not read or write any part of 2881** a block of memory after it has been released using 2882** [sqlite3_free()] or [sqlite3_realloc()]. 2883*/ 2884void *sqlite3_malloc(int); 2885void *sqlite3_malloc64(sqlite3_uint64); 2886void *sqlite3_realloc(void*, int); 2887void *sqlite3_realloc64(void*, sqlite3_uint64); 2888void sqlite3_free(void*); 2889sqlite3_uint64 sqlite3_msize(void*); 2890 2891/* 2892** CAPI3REF: Memory Allocator Statistics 2893** 2894** SQLite provides these two interfaces for reporting on the status 2895** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2896** routines, which form the built-in memory allocation subsystem. 2897** 2898** ^The [sqlite3_memory_used()] routine returns the number of bytes 2899** of memory currently outstanding (malloced but not freed). 2900** ^The [sqlite3_memory_highwater()] routine returns the maximum 2901** value of [sqlite3_memory_used()] since the high-water mark 2902** was last reset. ^The values returned by [sqlite3_memory_used()] and 2903** [sqlite3_memory_highwater()] include any overhead 2904** added by SQLite in its implementation of [sqlite3_malloc()], 2905** but not overhead added by the any underlying system library 2906** routines that [sqlite3_malloc()] may call. 2907** 2908** ^The memory high-water mark is reset to the current value of 2909** [sqlite3_memory_used()] if and only if the parameter to 2910** [sqlite3_memory_highwater()] is true. ^The value returned 2911** by [sqlite3_memory_highwater(1)] is the high-water mark 2912** prior to the reset. 2913*/ 2914sqlite3_int64 sqlite3_memory_used(void); 2915sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2916 2917/* 2918** CAPI3REF: Pseudo-Random Number Generator 2919** 2920** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2921** select random [ROWID | ROWIDs] when inserting new records into a table that 2922** already uses the largest possible [ROWID]. The PRNG is also used for 2923** the built-in random() and randomblob() SQL functions. This interface allows 2924** applications to access the same PRNG for other purposes. 2925** 2926** ^A call to this routine stores N bytes of randomness into buffer P. 2927** ^The P parameter can be a NULL pointer. 2928** 2929** ^If this routine has not been previously called or if the previous 2930** call had N less than one or a NULL pointer for P, then the PRNG is 2931** seeded using randomness obtained from the xRandomness method of 2932** the default [sqlite3_vfs] object. 2933** ^If the previous call to this routine had an N of 1 or more and a 2934** non-NULL P then the pseudo-randomness is generated 2935** internally and without recourse to the [sqlite3_vfs] xRandomness 2936** method. 2937*/ 2938void sqlite3_randomness(int N, void *P); 2939 2940/* 2941** CAPI3REF: Compile-Time Authorization Callbacks 2942** METHOD: sqlite3 2943** KEYWORDS: {authorizer callback} 2944** 2945** ^This routine registers an authorizer callback with a particular 2946** [database connection], supplied in the first argument. 2947** ^The authorizer callback is invoked as SQL statements are being compiled 2948** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2949** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2950** and [sqlite3_prepare16_v3()]. ^At various 2951** points during the compilation process, as logic is being created 2952** to perform various actions, the authorizer callback is invoked to 2953** see if those actions are allowed. ^The authorizer callback should 2954** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2955** specific action but allow the SQL statement to continue to be 2956** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2957** rejected with an error. ^If the authorizer callback returns 2958** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2959** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2960** the authorizer will fail with an error message. 2961** 2962** When the callback returns [SQLITE_OK], that means the operation 2963** requested is ok. ^When the callback returns [SQLITE_DENY], the 2964** [sqlite3_prepare_v2()] or equivalent call that triggered the 2965** authorizer will fail with an error message explaining that 2966** access is denied. 2967** 2968** ^The first parameter to the authorizer callback is a copy of the third 2969** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2970** to the callback is an integer [SQLITE_COPY | action code] that specifies 2971** the particular action to be authorized. ^The third through sixth parameters 2972** to the callback are either NULL pointers or zero-terminated strings 2973** that contain additional details about the action to be authorized. 2974** Applications must always be prepared to encounter a NULL pointer in any 2975** of the third through the sixth parameters of the authorization callback. 2976** 2977** ^If the action code is [SQLITE_READ] 2978** and the callback returns [SQLITE_IGNORE] then the 2979** [prepared statement] statement is constructed to substitute 2980** a NULL value in place of the table column that would have 2981** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2982** return can be used to deny an untrusted user access to individual 2983** columns of a table. 2984** ^When a table is referenced by a [SELECT] but no column values are 2985** extracted from that table (for example in a query like 2986** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2987** is invoked once for that table with a column name that is an empty string. 2988** ^If the action code is [SQLITE_DELETE] and the callback returns 2989** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2990** [truncate optimization] is disabled and all rows are deleted individually. 2991** 2992** An authorizer is used when [sqlite3_prepare | preparing] 2993** SQL statements from an untrusted source, to ensure that the SQL statements 2994** do not try to access data they are not allowed to see, or that they do not 2995** try to execute malicious statements that damage the database. For 2996** example, an application may allow a user to enter arbitrary 2997** SQL queries for evaluation by a database. But the application does 2998** not want the user to be able to make arbitrary changes to the 2999** database. An authorizer could then be put in place while the 3000** user-entered SQL is being [sqlite3_prepare | prepared] that 3001** disallows everything except [SELECT] statements. 3002** 3003** Applications that need to process SQL from untrusted sources 3004** might also consider lowering resource limits using [sqlite3_limit()] 3005** and limiting database size using the [max_page_count] [PRAGMA] 3006** in addition to using an authorizer. 3007** 3008** ^(Only a single authorizer can be in place on a database connection 3009** at a time. Each call to sqlite3_set_authorizer overrides the 3010** previous call.)^ ^Disable the authorizer by installing a NULL callback. 3011** The authorizer is disabled by default. 3012** 3013** The authorizer callback must not do anything that will modify 3014** the database connection that invoked the authorizer callback. 3015** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3016** database connections for the meaning of "modify" in this paragraph. 3017** 3018** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 3019** statement might be re-prepared during [sqlite3_step()] due to a 3020** schema change. Hence, the application should ensure that the 3021** correct authorizer callback remains in place during the [sqlite3_step()]. 3022** 3023** ^Note that the authorizer callback is invoked only during 3024** [sqlite3_prepare()] or its variants. Authorization is not 3025** performed during statement evaluation in [sqlite3_step()], unless 3026** as stated in the previous paragraph, sqlite3_step() invokes 3027** sqlite3_prepare_v2() to reprepare a statement after a schema change. 3028*/ 3029int sqlite3_set_authorizer( 3030 sqlite3*, 3031 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 3032 void *pUserData 3033); 3034 3035/* 3036** CAPI3REF: Authorizer Return Codes 3037** 3038** The [sqlite3_set_authorizer | authorizer callback function] must 3039** return either [SQLITE_OK] or one of these two constants in order 3040** to signal SQLite whether or not the action is permitted. See the 3041** [sqlite3_set_authorizer | authorizer documentation] for additional 3042** information. 3043** 3044** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 3045** returned from the [sqlite3_vtab_on_conflict()] interface. 3046*/ 3047#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 3048#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 3049 3050/* 3051** CAPI3REF: Authorizer Action Codes 3052** 3053** The [sqlite3_set_authorizer()] interface registers a callback function 3054** that is invoked to authorize certain SQL statement actions. The 3055** second parameter to the callback is an integer code that specifies 3056** what action is being authorized. These are the integer action codes that 3057** the authorizer callback may be passed. 3058** 3059** These action code values signify what kind of operation is to be 3060** authorized. The 3rd and 4th parameters to the authorization 3061** callback function will be parameters or NULL depending on which of these 3062** codes is used as the second parameter. ^(The 5th parameter to the 3063** authorizer callback is the name of the database ("main", "temp", 3064** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 3065** is the name of the inner-most trigger or view that is responsible for 3066** the access attempt or NULL if this access attempt is directly from 3067** top-level SQL code. 3068*/ 3069/******************************************* 3rd ************ 4th ***********/ 3070#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 3071#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 3072#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 3073#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 3074#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 3075#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 3076#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 3077#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 3078#define SQLITE_DELETE 9 /* Table Name NULL */ 3079#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 3080#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 3081#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 3082#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 3083#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 3084#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 3085#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 3086#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 3087#define SQLITE_INSERT 18 /* Table Name NULL */ 3088#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 3089#define SQLITE_READ 20 /* Table Name Column Name */ 3090#define SQLITE_SELECT 21 /* NULL NULL */ 3091#define SQLITE_TRANSACTION 22 /* Operation NULL */ 3092#define SQLITE_UPDATE 23 /* Table Name Column Name */ 3093#define SQLITE_ATTACH 24 /* Filename NULL */ 3094#define SQLITE_DETACH 25 /* Database Name NULL */ 3095#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 3096#define SQLITE_REINDEX 27 /* Index Name NULL */ 3097#define SQLITE_ANALYZE 28 /* Table Name NULL */ 3098#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 3099#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 3100#define SQLITE_FUNCTION 31 /* NULL Function Name */ 3101#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 3102#define SQLITE_COPY 0 /* No longer used */ 3103#define SQLITE_RECURSIVE 33 /* NULL NULL */ 3104 3105/* 3106** CAPI3REF: Tracing And Profiling Functions 3107** METHOD: sqlite3 3108** 3109** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 3110** instead of the routines described here. 3111** 3112** These routines register callback functions that can be used for 3113** tracing and profiling the execution of SQL statements. 3114** 3115** ^The callback function registered by sqlite3_trace() is invoked at 3116** various times when an SQL statement is being run by [sqlite3_step()]. 3117** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 3118** SQL statement text as the statement first begins executing. 3119** ^(Additional sqlite3_trace() callbacks might occur 3120** as each triggered subprogram is entered. The callbacks for triggers 3121** contain a UTF-8 SQL comment that identifies the trigger.)^ 3122** 3123** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 3124** the length of [bound parameter] expansion in the output of sqlite3_trace(). 3125** 3126** ^The callback function registered by sqlite3_profile() is invoked 3127** as each SQL statement finishes. ^The profile callback contains 3128** the original statement text and an estimate of wall-clock time 3129** of how long that statement took to run. ^The profile callback 3130** time is in units of nanoseconds, however the current implementation 3131** is only capable of millisecond resolution so the six least significant 3132** digits in the time are meaningless. Future versions of SQLite 3133** might provide greater resolution on the profiler callback. Invoking 3134** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the 3135** profile callback. 3136*/ 3137SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 3138 void(*xTrace)(void*,const char*), void*); 3139SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 3140 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 3141 3142/* 3143** CAPI3REF: SQL Trace Event Codes 3144** KEYWORDS: SQLITE_TRACE 3145** 3146** These constants identify classes of events that can be monitored 3147** using the [sqlite3_trace_v2()] tracing logic. The M argument 3148** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 3149** the following constants. ^The first argument to the trace callback 3150** is one of the following constants. 3151** 3152** New tracing constants may be added in future releases. 3153** 3154** ^A trace callback has four arguments: xCallback(T,C,P,X). 3155** ^The T argument is one of the integer type codes above. 3156** ^The C argument is a copy of the context pointer passed in as the 3157** fourth argument to [sqlite3_trace_v2()]. 3158** The P and X arguments are pointers whose meanings depend on T. 3159** 3160** <dl> 3161** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 3162** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 3163** first begins running and possibly at other times during the 3164** execution of the prepared statement, such as at the start of each 3165** trigger subprogram. ^The P argument is a pointer to the 3166** [prepared statement]. ^The X argument is a pointer to a string which 3167** is the unexpanded SQL text of the prepared statement or an SQL comment 3168** that indicates the invocation of a trigger. ^The callback can compute 3169** the same text that would have been returned by the legacy [sqlite3_trace()] 3170** interface by using the X argument when X begins with "--" and invoking 3171** [sqlite3_expanded_sql(P)] otherwise. 3172** 3173** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 3174** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 3175** information as is provided by the [sqlite3_profile()] callback. 3176** ^The P argument is a pointer to the [prepared statement] and the 3177** X argument points to a 64-bit integer which is the estimated of 3178** the number of nanosecond that the prepared statement took to run. 3179** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 3180** 3181** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 3182** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 3183** statement generates a single row of result. 3184** ^The P argument is a pointer to the [prepared statement] and the 3185** X argument is unused. 3186** 3187** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 3188** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 3189** connection closes. 3190** ^The P argument is a pointer to the [database connection] object 3191** and the X argument is unused. 3192** </dl> 3193*/ 3194#define SQLITE_TRACE_STMT 0x01 3195#define SQLITE_TRACE_PROFILE 0x02 3196#define SQLITE_TRACE_ROW 0x04 3197#define SQLITE_TRACE_CLOSE 0x08 3198 3199/* 3200** CAPI3REF: SQL Trace Hook 3201** METHOD: sqlite3 3202** 3203** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3204** function X against [database connection] D, using property mask M 3205** and context pointer P. ^If the X callback is 3206** NULL or if the M mask is zero, then tracing is disabled. The 3207** M argument should be the bitwise OR-ed combination of 3208** zero or more [SQLITE_TRACE] constants. 3209** 3210** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3211** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3212** 3213** ^The X callback is invoked whenever any of the events identified by 3214** mask M occur. ^The integer return value from the callback is currently 3215** ignored, though this may change in future releases. Callback 3216** implementations should return zero to ensure future compatibility. 3217** 3218** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3219** ^The T argument is one of the [SQLITE_TRACE] 3220** constants to indicate why the callback was invoked. 3221** ^The C argument is a copy of the context pointer. 3222** The P and X arguments are pointers whose meanings depend on T. 3223** 3224** The sqlite3_trace_v2() interface is intended to replace the legacy 3225** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3226** are deprecated. 3227*/ 3228int sqlite3_trace_v2( 3229 sqlite3*, 3230 unsigned uMask, 3231 int(*xCallback)(unsigned,void*,void*,void*), 3232 void *pCtx 3233); 3234 3235/* 3236** CAPI3REF: Query Progress Callbacks 3237** METHOD: sqlite3 3238** 3239** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3240** function X to be invoked periodically during long running calls to 3241** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3242** database connection D. An example use for this 3243** interface is to keep a GUI updated during a large query. 3244** 3245** ^The parameter P is passed through as the only parameter to the 3246** callback function X. ^The parameter N is the approximate number of 3247** [virtual machine instructions] that are evaluated between successive 3248** invocations of the callback X. ^If N is less than one then the progress 3249** handler is disabled. 3250** 3251** ^Only a single progress handler may be defined at one time per 3252** [database connection]; setting a new progress handler cancels the 3253** old one. ^Setting parameter X to NULL disables the progress handler. 3254** ^The progress handler is also disabled by setting N to a value less 3255** than 1. 3256** 3257** ^If the progress callback returns non-zero, the operation is 3258** interrupted. This feature can be used to implement a 3259** "Cancel" button on a GUI progress dialog box. 3260** 3261** The progress handler callback must not do anything that will modify 3262** the database connection that invoked the progress handler. 3263** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3264** database connections for the meaning of "modify" in this paragraph. 3265** 3266*/ 3267void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3268 3269/* 3270** CAPI3REF: Opening A New Database Connection 3271** CONSTRUCTOR: sqlite3 3272** 3273** ^These routines open an SQLite database file as specified by the 3274** filename argument. ^The filename argument is interpreted as UTF-8 for 3275** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3276** order for sqlite3_open16(). ^(A [database connection] handle is usually 3277** returned in *ppDb, even if an error occurs. The only exception is that 3278** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3279** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3280** object.)^ ^(If the database is opened (and/or created) successfully, then 3281** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3282** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3283** an English language description of the error following a failure of any 3284** of the sqlite3_open() routines. 3285** 3286** ^The default encoding will be UTF-8 for databases created using 3287** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3288** created using sqlite3_open16() will be UTF-16 in the native byte order. 3289** 3290** Whether or not an error occurs when it is opened, resources 3291** associated with the [database connection] handle should be released by 3292** passing it to [sqlite3_close()] when it is no longer required. 3293** 3294** The sqlite3_open_v2() interface works like sqlite3_open() 3295** except that it accepts two additional parameters for additional control 3296** over the new database connection. ^(The flags parameter to 3297** sqlite3_open_v2() must include, at a minimum, one of the following 3298** three flag combinations:)^ 3299** 3300** <dl> 3301** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3302** <dd>The database is opened in read-only mode. If the database does not 3303** already exist, an error is returned.</dd>)^ 3304** 3305** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3306** <dd>The database is opened for reading and writing if possible, or reading 3307** only if the file is write protected by the operating system. In either 3308** case the database must already exist, otherwise an error is returned.</dd>)^ 3309** 3310** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3311** <dd>The database is opened for reading and writing, and is created if 3312** it does not already exist. This is the behavior that is always used for 3313** sqlite3_open() and sqlite3_open16().</dd>)^ 3314** </dl> 3315** 3316** In addition to the required flags, the following optional flags are 3317** also supported: 3318** 3319** <dl> 3320** ^(<dt>[SQLITE_OPEN_URI]</dt> 3321** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^ 3322** 3323** ^(<dt>[SQLITE_OPEN_MEMORY]</dt> 3324** <dd>The database will be opened as an in-memory database. The database 3325** is named by the "filename" argument for the purposes of cache-sharing, 3326** if shared cache mode is enabled, but the "filename" is otherwise ignored. 3327** </dd>)^ 3328** 3329** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt> 3330** <dd>The new database connection will use the "multi-thread" 3331** [threading mode].)^ This means that separate threads are allowed 3332** to use SQLite at the same time, as long as each thread is using 3333** a different [database connection]. 3334** 3335** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt> 3336** <dd>The new database connection will use the "serialized" 3337** [threading mode].)^ This means the multiple threads can safely 3338** attempt to use the same database connection at the same time. 3339** (Mutexes will block any actual concurrency, but in this mode 3340** there is no harm in trying.) 3341** 3342** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt> 3343** <dd>The database is opened [shared cache] enabled, overriding 3344** the default shared cache setting provided by 3345** [sqlite3_enable_shared_cache()].)^ 3346** 3347** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt> 3348** <dd>The database is opened [shared cache] disabled, overriding 3349** the default shared cache setting provided by 3350** [sqlite3_enable_shared_cache()].)^ 3351** 3352** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt> 3353** <dd>The database filename is not allowed to be a symbolic link</dd> 3354** </dl>)^ 3355** 3356** If the 3rd parameter to sqlite3_open_v2() is not one of the 3357** required combinations shown above optionally combined with other 3358** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3359** then the behavior is undefined. 3360** 3361** ^The fourth parameter to sqlite3_open_v2() is the name of the 3362** [sqlite3_vfs] object that defines the operating system interface that 3363** the new database connection should use. ^If the fourth parameter is 3364** a NULL pointer then the default [sqlite3_vfs] object is used. 3365** 3366** ^If the filename is ":memory:", then a private, temporary in-memory database 3367** is created for the connection. ^This in-memory database will vanish when 3368** the database connection is closed. Future versions of SQLite might 3369** make use of additional special filenames that begin with the ":" character. 3370** It is recommended that when a database filename actually does begin with 3371** a ":" character you should prefix the filename with a pathname such as 3372** "./" to avoid ambiguity. 3373** 3374** ^If the filename is an empty string, then a private, temporary 3375** on-disk database will be created. ^This private database will be 3376** automatically deleted as soon as the database connection is closed. 3377** 3378** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3379** 3380** ^If [URI filename] interpretation is enabled, and the filename argument 3381** begins with "file:", then the filename is interpreted as a URI. ^URI 3382** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3383** set in the third argument to sqlite3_open_v2(), or if it has 3384** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3385** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3386** URI filename interpretation is turned off 3387** by default, but future releases of SQLite might enable URI filename 3388** interpretation by default. See "[URI filenames]" for additional 3389** information. 3390** 3391** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3392** authority, then it must be either an empty string or the string 3393** "localhost". ^If the authority is not an empty string or "localhost", an 3394** error is returned to the caller. ^The fragment component of a URI, if 3395** present, is ignored. 3396** 3397** ^SQLite uses the path component of the URI as the name of the disk file 3398** which contains the database. ^If the path begins with a '/' character, 3399** then it is interpreted as an absolute path. ^If the path does not begin 3400** with a '/' (meaning that the authority section is omitted from the URI) 3401** then the path is interpreted as a relative path. 3402** ^(On windows, the first component of an absolute path 3403** is a drive specification (e.g. "C:").)^ 3404** 3405** [[core URI query parameters]] 3406** The query component of a URI may contain parameters that are interpreted 3407** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3408** SQLite and its built-in [VFSes] interpret the 3409** following query parameters: 3410** 3411** <ul> 3412** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3413** a VFS object that provides the operating system interface that should 3414** be used to access the database file on disk. ^If this option is set to 3415** an empty string the default VFS object is used. ^Specifying an unknown 3416** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3417** present, then the VFS specified by the option takes precedence over 3418** the value passed as the fourth parameter to sqlite3_open_v2(). 3419** 3420** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3421** "rwc", or "memory". Attempting to set it to any other value is 3422** an error)^. 3423** ^If "ro" is specified, then the database is opened for read-only 3424** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3425** third argument to sqlite3_open_v2(). ^If the mode option is set to 3426** "rw", then the database is opened for read-write (but not create) 3427** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3428** been set. ^Value "rwc" is equivalent to setting both 3429** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3430** set to "memory" then a pure [in-memory database] that never reads 3431** or writes from disk is used. ^It is an error to specify a value for 3432** the mode parameter that is less restrictive than that specified by 3433** the flags passed in the third parameter to sqlite3_open_v2(). 3434** 3435** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3436** "private". ^Setting it to "shared" is equivalent to setting the 3437** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3438** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3439** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3440** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3441** a URI filename, its value overrides any behavior requested by setting 3442** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3443** 3444** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3445** [powersafe overwrite] property does or does not apply to the 3446** storage media on which the database file resides. 3447** 3448** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3449** which if set disables file locking in rollback journal modes. This 3450** is useful for accessing a database on a filesystem that does not 3451** support locking. Caution: Database corruption might result if two 3452** or more processes write to the same database and any one of those 3453** processes uses nolock=1. 3454** 3455** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3456** parameter that indicates that the database file is stored on 3457** read-only media. ^When immutable is set, SQLite assumes that the 3458** database file cannot be changed, even by a process with higher 3459** privilege, and so the database is opened read-only and all locking 3460** and change detection is disabled. Caution: Setting the immutable 3461** property on a database file that does in fact change can result 3462** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3463** See also: [SQLITE_IOCAP_IMMUTABLE]. 3464** 3465** </ul> 3466** 3467** ^Specifying an unknown parameter in the query component of a URI is not an 3468** error. Future versions of SQLite might understand additional query 3469** parameters. See "[query parameters with special meaning to SQLite]" for 3470** additional information. 3471** 3472** [[URI filename examples]] <h3>URI filename examples</h3> 3473** 3474** <table border="1" align=center cellpadding=5> 3475** <tr><th> URI filenames <th> Results 3476** <tr><td> file:data.db <td> 3477** Open the file "data.db" in the current directory. 3478** <tr><td> file:/home/fred/data.db<br> 3479** file:///home/fred/data.db <br> 3480** file://localhost/home/fred/data.db <br> <td> 3481** Open the database file "/home/fred/data.db". 3482** <tr><td> file://darkstar/home/fred/data.db <td> 3483** An error. "darkstar" is not a recognized authority. 3484** <tr><td style="white-space:nowrap"> 3485** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3486** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3487** C:. Note that the %20 escaping in this example is not strictly 3488** necessary - space characters can be used literally 3489** in URI filenames. 3490** <tr><td> file:data.db?mode=ro&cache=private <td> 3491** Open file "data.db" in the current directory for read-only access. 3492** Regardless of whether or not shared-cache mode is enabled by 3493** default, use a private cache. 3494** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3495** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3496** that uses dot-files in place of posix advisory locking. 3497** <tr><td> file:data.db?mode=readonly <td> 3498** An error. "readonly" is not a valid option for the "mode" parameter. 3499** </table> 3500** 3501** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3502** query components of a URI. A hexadecimal escape sequence consists of a 3503** percent sign - "%" - followed by exactly two hexadecimal digits 3504** specifying an octet value. ^Before the path or query components of a 3505** URI filename are interpreted, they are encoded using UTF-8 and all 3506** hexadecimal escape sequences replaced by a single byte containing the 3507** corresponding octet. If this process generates an invalid UTF-8 encoding, 3508** the results are undefined. 3509** 3510** <b>Note to Windows users:</b> The encoding used for the filename argument 3511** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3512** codepage is currently defined. Filenames containing international 3513** characters must be converted to UTF-8 prior to passing them into 3514** sqlite3_open() or sqlite3_open_v2(). 3515** 3516** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3517** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3518** features that require the use of temporary files may fail. 3519** 3520** See also: [sqlite3_temp_directory] 3521*/ 3522int sqlite3_open( 3523 const char *filename, /* Database filename (UTF-8) */ 3524 sqlite3 **ppDb /* OUT: SQLite db handle */ 3525); 3526int sqlite3_open16( 3527 const void *filename, /* Database filename (UTF-16) */ 3528 sqlite3 **ppDb /* OUT: SQLite db handle */ 3529); 3530int sqlite3_open_v2( 3531 const char *filename, /* Database filename (UTF-8) */ 3532 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3533 int flags, /* Flags */ 3534 const char *zVfs /* Name of VFS module to use */ 3535); 3536 3537/* 3538** CAPI3REF: Obtain Values For URI Parameters 3539** 3540** These are utility routines, useful to [VFS|custom VFS implementations], 3541** that check if a database file was a URI that contained a specific query 3542** parameter, and if so obtains the value of that query parameter. 3543** 3544** The first parameter to these interfaces (hereafter referred to 3545** as F) must be one of: 3546** <ul> 3547** <li> A database filename pointer created by the SQLite core and 3548** passed into the xOpen() method of a VFS implemention, or 3549** <li> A filename obtained from [sqlite3_db_filename()], or 3550** <li> A new filename constructed using [sqlite3_create_filename()]. 3551** </ul> 3552** If the F parameter is not one of the above, then the behavior is 3553** undefined and probably undesirable. Older versions of SQLite were 3554** more tolerant of invalid F parameters than newer versions. 3555** 3556** If F is a suitable filename (as described in the previous paragraph) 3557** and if P is the name of the query parameter, then 3558** sqlite3_uri_parameter(F,P) returns the value of the P 3559** parameter if it exists or a NULL pointer if P does not appear as a 3560** query parameter on F. If P is a query parameter of F and it 3561** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3562** a pointer to an empty string. 3563** 3564** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3565** parameter and returns true (1) or false (0) according to the value 3566** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3567** value of query parameter P is one of "yes", "true", or "on" in any 3568** case or if the value begins with a non-zero number. The 3569** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3570** query parameter P is one of "no", "false", or "off" in any case or 3571** if the value begins with a numeric zero. If P is not a query 3572** parameter on F or if the value of P does not match any of the 3573** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3574** 3575** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3576** 64-bit signed integer and returns that integer, or D if P does not 3577** exist. If the value of P is something other than an integer, then 3578** zero is returned. 3579** 3580** The sqlite3_uri_key(F,N) returns a pointer to the name (not 3581** the value) of the N-th query parameter for filename F, or a NULL 3582** pointer if N is less than zero or greater than the number of query 3583** parameters minus 1. The N value is zero-based so N should be 0 to obtain 3584** the name of the first query parameter, 1 for the second parameter, and 3585** so forth. 3586** 3587** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3588** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3589** is not a database file pathname pointer that the SQLite core passed 3590** into the xOpen VFS method, then the behavior of this routine is undefined 3591** and probably undesirable. 3592** 3593** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F 3594** parameter can also be the name of a rollback journal file or WAL file 3595** in addition to the main database file. Prior to version 3.31.0, these 3596** routines would only work if F was the name of the main database file. 3597** When the F parameter is the name of the rollback journal or WAL file, 3598** it has access to all the same query parameters as were found on the 3599** main database file. 3600** 3601** See the [URI filename] documentation for additional information. 3602*/ 3603const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3604int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3605sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3606const char *sqlite3_uri_key(const char *zFilename, int N); 3607 3608/* 3609** CAPI3REF: Translate filenames 3610** 3611** These routines are available to [VFS|custom VFS implementations] for 3612** translating filenames between the main database file, the journal file, 3613** and the WAL file. 3614** 3615** If F is the name of an sqlite database file, journal file, or WAL file 3616** passed by the SQLite core into the VFS, then sqlite3_filename_database(F) 3617** returns the name of the corresponding database file. 3618** 3619** If F is the name of an sqlite database file, journal file, or WAL file 3620** passed by the SQLite core into the VFS, or if F is a database filename 3621** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F) 3622** returns the name of the corresponding rollback journal file. 3623** 3624** If F is the name of an sqlite database file, journal file, or WAL file 3625** that was passed by the SQLite core into the VFS, or if F is a database 3626** filename obtained from [sqlite3_db_filename()], then 3627** sqlite3_filename_wal(F) returns the name of the corresponding 3628** WAL file. 3629** 3630** In all of the above, if F is not the name of a database, journal or WAL 3631** filename passed into the VFS from the SQLite core and F is not the 3632** return value from [sqlite3_db_filename()], then the result is 3633** undefined and is likely a memory access violation. 3634*/ 3635const char *sqlite3_filename_database(const char*); 3636const char *sqlite3_filename_journal(const char*); 3637const char *sqlite3_filename_wal(const char*); 3638 3639/* 3640** CAPI3REF: Database File Corresponding To A Journal 3641** 3642** ^If X is the name of a rollback or WAL-mode journal file that is 3643** passed into the xOpen method of [sqlite3_vfs], then 3644** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file] 3645** object that represents the main database file. 3646** 3647** This routine is intended for use in custom [VFS] implementations 3648** only. It is not a general-purpose interface. 3649** The argument sqlite3_file_object(X) must be a filename pointer that 3650** has been passed into [sqlite3_vfs].xOpen method where the 3651** flags parameter to xOpen contains one of the bits 3652** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL]. Any other use 3653** of this routine results in undefined and probably undesirable 3654** behavior. 3655*/ 3656sqlite3_file *sqlite3_database_file_object(const char*); 3657 3658/* 3659** CAPI3REF: Create and Destroy VFS Filenames 3660** 3661** These interfces are provided for use by [VFS shim] implementations and 3662** are not useful outside of that context. 3663** 3664** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of 3665** database filename D with corresponding journal file J and WAL file W and 3666** with N URI parameters key/values pairs in the array P. The result from 3667** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that 3668** is safe to pass to routines like: 3669** <ul> 3670** <li> [sqlite3_uri_parameter()], 3671** <li> [sqlite3_uri_boolean()], 3672** <li> [sqlite3_uri_int64()], 3673** <li> [sqlite3_uri_key()], 3674** <li> [sqlite3_filename_database()], 3675** <li> [sqlite3_filename_journal()], or 3676** <li> [sqlite3_filename_wal()]. 3677** </ul> 3678** If a memory allocation error occurs, sqlite3_create_filename() might 3679** return a NULL pointer. The memory obtained from sqlite3_create_filename(X) 3680** must be released by a corresponding call to sqlite3_free_filename(Y). 3681** 3682** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array 3683** of 2*N pointers to strings. Each pair of pointers in this array corresponds 3684** to a key and value for a query parameter. The P parameter may be a NULL 3685** pointer if N is zero. None of the 2*N pointers in the P array may be 3686** NULL pointers and key pointers should not be empty strings. 3687** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may 3688** be NULL pointers, though they can be empty strings. 3689** 3690** The sqlite3_free_filename(Y) routine releases a memory allocation 3691** previously obtained from sqlite3_create_filename(). Invoking 3692** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op. 3693** 3694** If the Y parameter to sqlite3_free_filename(Y) is anything other 3695** than a NULL pointer or a pointer previously acquired from 3696** sqlite3_create_filename(), then bad things such as heap 3697** corruption or segfaults may occur. The value Y should be 3698** used again after sqlite3_free_filename(Y) has been called. This means 3699** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y, 3700** then the corresponding [sqlite3_module.xClose() method should also be 3701** invoked prior to calling sqlite3_free_filename(Y). 3702*/ 3703char *sqlite3_create_filename( 3704 const char *zDatabase, 3705 const char *zJournal, 3706 const char *zWal, 3707 int nParam, 3708 const char **azParam 3709); 3710void sqlite3_free_filename(char*); 3711 3712/* 3713** CAPI3REF: Error Codes And Messages 3714** METHOD: sqlite3 3715** 3716** ^If the most recent sqlite3_* API call associated with 3717** [database connection] D failed, then the sqlite3_errcode(D) interface 3718** returns the numeric [result code] or [extended result code] for that 3719** API call. 3720** ^The sqlite3_extended_errcode() 3721** interface is the same except that it always returns the 3722** [extended result code] even when extended result codes are 3723** disabled. 3724** 3725** The values returned by sqlite3_errcode() and/or 3726** sqlite3_extended_errcode() might change with each API call. 3727** Except, there are some interfaces that are guaranteed to never 3728** change the value of the error code. The error-code preserving 3729** interfaces are: 3730** 3731** <ul> 3732** <li> sqlite3_errcode() 3733** <li> sqlite3_extended_errcode() 3734** <li> sqlite3_errmsg() 3735** <li> sqlite3_errmsg16() 3736** </ul> 3737** 3738** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3739** text that describes the error, as either UTF-8 or UTF-16 respectively. 3740** ^(Memory to hold the error message string is managed internally. 3741** The application does not need to worry about freeing the result. 3742** However, the error string might be overwritten or deallocated by 3743** subsequent calls to other SQLite interface functions.)^ 3744** 3745** ^The sqlite3_errstr() interface returns the English-language text 3746** that describes the [result code], as UTF-8. 3747** ^(Memory to hold the error message string is managed internally 3748** and must not be freed by the application)^. 3749** 3750** When the serialized [threading mode] is in use, it might be the 3751** case that a second error occurs on a separate thread in between 3752** the time of the first error and the call to these interfaces. 3753** When that happens, the second error will be reported since these 3754** interfaces always report the most recent result. To avoid 3755** this, each thread can obtain exclusive use of the [database connection] D 3756** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3757** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3758** all calls to the interfaces listed here are completed. 3759** 3760** If an interface fails with SQLITE_MISUSE, that means the interface 3761** was invoked incorrectly by the application. In that case, the 3762** error code and message may or may not be set. 3763*/ 3764int sqlite3_errcode(sqlite3 *db); 3765int sqlite3_extended_errcode(sqlite3 *db); 3766const char *sqlite3_errmsg(sqlite3*); 3767const void *sqlite3_errmsg16(sqlite3*); 3768const char *sqlite3_errstr(int); 3769 3770/* 3771** CAPI3REF: Prepared Statement Object 3772** KEYWORDS: {prepared statement} {prepared statements} 3773** 3774** An instance of this object represents a single SQL statement that 3775** has been compiled into binary form and is ready to be evaluated. 3776** 3777** Think of each SQL statement as a separate computer program. The 3778** original SQL text is source code. A prepared statement object 3779** is the compiled object code. All SQL must be converted into a 3780** prepared statement before it can be run. 3781** 3782** The life-cycle of a prepared statement object usually goes like this: 3783** 3784** <ol> 3785** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3786** <li> Bind values to [parameters] using the sqlite3_bind_*() 3787** interfaces. 3788** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3789** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3790** to step 2. Do this zero or more times. 3791** <li> Destroy the object using [sqlite3_finalize()]. 3792** </ol> 3793*/ 3794typedef struct sqlite3_stmt sqlite3_stmt; 3795 3796/* 3797** CAPI3REF: Run-time Limits 3798** METHOD: sqlite3 3799** 3800** ^(This interface allows the size of various constructs to be limited 3801** on a connection by connection basis. The first parameter is the 3802** [database connection] whose limit is to be set or queried. The 3803** second parameter is one of the [limit categories] that define a 3804** class of constructs to be size limited. The third parameter is the 3805** new limit for that construct.)^ 3806** 3807** ^If the new limit is a negative number, the limit is unchanged. 3808** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3809** [limits | hard upper bound] 3810** set at compile-time by a C preprocessor macro called 3811** [limits | SQLITE_MAX_<i>NAME</i>]. 3812** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3813** ^Attempts to increase a limit above its hard upper bound are 3814** silently truncated to the hard upper bound. 3815** 3816** ^Regardless of whether or not the limit was changed, the 3817** [sqlite3_limit()] interface returns the prior value of the limit. 3818** ^Hence, to find the current value of a limit without changing it, 3819** simply invoke this interface with the third parameter set to -1. 3820** 3821** Run-time limits are intended for use in applications that manage 3822** both their own internal database and also databases that are controlled 3823** by untrusted external sources. An example application might be a 3824** web browser that has its own databases for storing history and 3825** separate databases controlled by JavaScript applications downloaded 3826** off the Internet. The internal databases can be given the 3827** large, default limits. Databases managed by external sources can 3828** be given much smaller limits designed to prevent a denial of service 3829** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3830** interface to further control untrusted SQL. The size of the database 3831** created by an untrusted script can be contained using the 3832** [max_page_count] [PRAGMA]. 3833** 3834** New run-time limit categories may be added in future releases. 3835*/ 3836int sqlite3_limit(sqlite3*, int id, int newVal); 3837 3838/* 3839** CAPI3REF: Run-Time Limit Categories 3840** KEYWORDS: {limit category} {*limit categories} 3841** 3842** These constants define various performance limits 3843** that can be lowered at run-time using [sqlite3_limit()]. 3844** The synopsis of the meanings of the various limits is shown below. 3845** Additional information is available at [limits | Limits in SQLite]. 3846** 3847** <dl> 3848** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3849** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3850** 3851** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3852** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3853** 3854** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3855** <dd>The maximum number of columns in a table definition or in the 3856** result set of a [SELECT] or the maximum number of columns in an index 3857** or in an ORDER BY or GROUP BY clause.</dd>)^ 3858** 3859** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3860** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3861** 3862** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3863** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3864** 3865** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3866** <dd>The maximum number of instructions in a virtual machine program 3867** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3868** the equivalent tries to allocate space for more than this many opcodes 3869** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3870** 3871** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3872** <dd>The maximum number of arguments on a function.</dd>)^ 3873** 3874** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3875** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3876** 3877** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3878** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3879** <dd>The maximum length of the pattern argument to the [LIKE] or 3880** [GLOB] operators.</dd>)^ 3881** 3882** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3883** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3884** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3885** 3886** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3887** <dd>The maximum depth of recursion for triggers.</dd>)^ 3888** 3889** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3890** <dd>The maximum number of auxiliary worker threads that a single 3891** [prepared statement] may start.</dd>)^ 3892** </dl> 3893*/ 3894#define SQLITE_LIMIT_LENGTH 0 3895#define SQLITE_LIMIT_SQL_LENGTH 1 3896#define SQLITE_LIMIT_COLUMN 2 3897#define SQLITE_LIMIT_EXPR_DEPTH 3 3898#define SQLITE_LIMIT_COMPOUND_SELECT 4 3899#define SQLITE_LIMIT_VDBE_OP 5 3900#define SQLITE_LIMIT_FUNCTION_ARG 6 3901#define SQLITE_LIMIT_ATTACHED 7 3902#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3903#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3904#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3905#define SQLITE_LIMIT_WORKER_THREADS 11 3906 3907/* 3908** CAPI3REF: Prepare Flags 3909** 3910** These constants define various flags that can be passed into 3911** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3912** [sqlite3_prepare16_v3()] interfaces. 3913** 3914** New flags may be added in future releases of SQLite. 3915** 3916** <dl> 3917** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3918** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3919** that the prepared statement will be retained for a long time and 3920** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3921** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3922** be used just once or at most a few times and then destroyed using 3923** [sqlite3_finalize()] relatively soon. The current implementation acts 3924** on this hint by avoiding the use of [lookaside memory] so as not to 3925** deplete the limited store of lookaside memory. Future versions of 3926** SQLite may act on this hint differently. 3927** 3928** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt> 3929** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used 3930** to be required for any prepared statement that wanted to use the 3931** [sqlite3_normalized_sql()] interface. However, the 3932** [sqlite3_normalized_sql()] interface is now available to all 3933** prepared statements, regardless of whether or not they use this 3934** flag. 3935** 3936** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt> 3937** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler 3938** to return an error (error code SQLITE_ERROR) if the statement uses 3939** any virtual tables. 3940** </dl> 3941*/ 3942#define SQLITE_PREPARE_PERSISTENT 0x01 3943#define SQLITE_PREPARE_NORMALIZE 0x02 3944#define SQLITE_PREPARE_NO_VTAB 0x04 3945 3946/* 3947** CAPI3REF: Compiling An SQL Statement 3948** KEYWORDS: {SQL statement compiler} 3949** METHOD: sqlite3 3950** CONSTRUCTOR: sqlite3_stmt 3951** 3952** To execute an SQL statement, it must first be compiled into a byte-code 3953** program using one of these routines. Or, in other words, these routines 3954** are constructors for the [prepared statement] object. 3955** 3956** The preferred routine to use is [sqlite3_prepare_v2()]. The 3957** [sqlite3_prepare()] interface is legacy and should be avoided. 3958** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3959** for special purposes. 3960** 3961** The use of the UTF-8 interfaces is preferred, as SQLite currently 3962** does all parsing using UTF-8. The UTF-16 interfaces are provided 3963** as a convenience. The UTF-16 interfaces work by converting the 3964** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3965** 3966** The first argument, "db", is a [database connection] obtained from a 3967** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3968** [sqlite3_open16()]. The database connection must not have been closed. 3969** 3970** The second argument, "zSql", is the statement to be compiled, encoded 3971** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3972** and sqlite3_prepare_v3() 3973** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3974** and sqlite3_prepare16_v3() use UTF-16. 3975** 3976** ^If the nByte argument is negative, then zSql is read up to the 3977** first zero terminator. ^If nByte is positive, then it is the 3978** number of bytes read from zSql. ^If nByte is zero, then no prepared 3979** statement is generated. 3980** If the caller knows that the supplied string is nul-terminated, then 3981** there is a small performance advantage to passing an nByte parameter that 3982** is the number of bytes in the input string <i>including</i> 3983** the nul-terminator. 3984** 3985** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3986** past the end of the first SQL statement in zSql. These routines only 3987** compile the first statement in zSql, so *pzTail is left pointing to 3988** what remains uncompiled. 3989** 3990** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3991** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3992** to NULL. ^If the input text contains no SQL (if the input is an empty 3993** string or a comment) then *ppStmt is set to NULL. 3994** The calling procedure is responsible for deleting the compiled 3995** SQL statement using [sqlite3_finalize()] after it has finished with it. 3996** ppStmt may not be NULL. 3997** 3998** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3999** otherwise an [error code] is returned. 4000** 4001** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 4002** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 4003** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 4004** are retained for backwards compatibility, but their use is discouraged. 4005** ^In the "vX" interfaces, the prepared statement 4006** that is returned (the [sqlite3_stmt] object) contains a copy of the 4007** original SQL text. This causes the [sqlite3_step()] interface to 4008** behave differently in three ways: 4009** 4010** <ol> 4011** <li> 4012** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 4013** always used to do, [sqlite3_step()] will automatically recompile the SQL 4014** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 4015** retries will occur before sqlite3_step() gives up and returns an error. 4016** </li> 4017** 4018** <li> 4019** ^When an error occurs, [sqlite3_step()] will return one of the detailed 4020** [error codes] or [extended error codes]. ^The legacy behavior was that 4021** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 4022** and the application would have to make a second call to [sqlite3_reset()] 4023** in order to find the underlying cause of the problem. With the "v2" prepare 4024** interfaces, the underlying reason for the error is returned immediately. 4025** </li> 4026** 4027** <li> 4028** ^If the specific value bound to a [parameter | host parameter] in the 4029** WHERE clause might influence the choice of query plan for a statement, 4030** then the statement will be automatically recompiled, as if there had been 4031** a schema change, on the first [sqlite3_step()] call following any change 4032** to the [sqlite3_bind_text | bindings] of that [parameter]. 4033** ^The specific value of a WHERE-clause [parameter] might influence the 4034** choice of query plan if the parameter is the left-hand side of a [LIKE] 4035** or [GLOB] operator or if the parameter is compared to an indexed column 4036** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled. 4037** </li> 4038** </ol> 4039** 4040** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 4041** the extra prepFlags parameter, which is a bit array consisting of zero or 4042** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 4043** sqlite3_prepare_v2() interface works exactly the same as 4044** sqlite3_prepare_v3() with a zero prepFlags parameter. 4045*/ 4046int sqlite3_prepare( 4047 sqlite3 *db, /* Database handle */ 4048 const char *zSql, /* SQL statement, UTF-8 encoded */ 4049 int nByte, /* Maximum length of zSql in bytes. */ 4050 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4051 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4052); 4053int sqlite3_prepare_v2( 4054 sqlite3 *db, /* Database handle */ 4055 const char *zSql, /* SQL statement, UTF-8 encoded */ 4056 int nByte, /* Maximum length of zSql in bytes. */ 4057 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4058 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4059); 4060int sqlite3_prepare_v3( 4061 sqlite3 *db, /* Database handle */ 4062 const char *zSql, /* SQL statement, UTF-8 encoded */ 4063 int nByte, /* Maximum length of zSql in bytes. */ 4064 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4065 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4066 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 4067); 4068int sqlite3_prepare16( 4069 sqlite3 *db, /* Database handle */ 4070 const void *zSql, /* SQL statement, UTF-16 encoded */ 4071 int nByte, /* Maximum length of zSql in bytes. */ 4072 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4073 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4074); 4075int sqlite3_prepare16_v2( 4076 sqlite3 *db, /* Database handle */ 4077 const void *zSql, /* SQL statement, UTF-16 encoded */ 4078 int nByte, /* Maximum length of zSql in bytes. */ 4079 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4080 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4081); 4082int sqlite3_prepare16_v3( 4083 sqlite3 *db, /* Database handle */ 4084 const void *zSql, /* SQL statement, UTF-16 encoded */ 4085 int nByte, /* Maximum length of zSql in bytes. */ 4086 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 4087 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 4088 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 4089); 4090 4091/* 4092** CAPI3REF: Retrieving Statement SQL 4093** METHOD: sqlite3_stmt 4094** 4095** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 4096** SQL text used to create [prepared statement] P if P was 4097** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 4098** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4099** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 4100** string containing the SQL text of prepared statement P with 4101** [bound parameters] expanded. 4102** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8 4103** string containing the normalized SQL text of prepared statement P. The 4104** semantics used to normalize a SQL statement are unspecified and subject 4105** to change. At a minimum, literal values will be replaced with suitable 4106** placeholders. 4107** 4108** ^(For example, if a prepared statement is created using the SQL 4109** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 4110** and parameter :xyz is unbound, then sqlite3_sql() will return 4111** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 4112** will return "SELECT 2345,NULL".)^ 4113** 4114** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 4115** is available to hold the result, or if the result would exceed the 4116** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 4117** 4118** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 4119** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 4120** option causes sqlite3_expanded_sql() to always return NULL. 4121** 4122** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P) 4123** are managed by SQLite and are automatically freed when the prepared 4124** statement is finalized. 4125** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 4126** is obtained from [sqlite3_malloc()] and must be free by the application 4127** by passing it to [sqlite3_free()]. 4128*/ 4129const char *sqlite3_sql(sqlite3_stmt *pStmt); 4130char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 4131const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt); 4132 4133/* 4134** CAPI3REF: Determine If An SQL Statement Writes The Database 4135** METHOD: sqlite3_stmt 4136** 4137** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 4138** and only if the [prepared statement] X makes no direct changes to 4139** the content of the database file. 4140** 4141** Note that [application-defined SQL functions] or 4142** [virtual tables] might change the database indirectly as a side effect. 4143** ^(For example, if an application defines a function "eval()" that 4144** calls [sqlite3_exec()], then the following SQL statement would 4145** change the database file through side-effects: 4146** 4147** <blockquote><pre> 4148** SELECT eval('DELETE FROM t1') FROM t2; 4149** </pre></blockquote> 4150** 4151** But because the [SELECT] statement does not change the database file 4152** directly, sqlite3_stmt_readonly() would still return true.)^ 4153** 4154** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 4155** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 4156** since the statements themselves do not actually modify the database but 4157** rather they control the timing of when other statements modify the 4158** database. ^The [ATTACH] and [DETACH] statements also cause 4159** sqlite3_stmt_readonly() to return true since, while those statements 4160** change the configuration of a database connection, they do not make 4161** changes to the content of the database files on disk. 4162** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 4163** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 4164** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 4165** sqlite3_stmt_readonly() returns false for those commands. 4166*/ 4167int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 4168 4169/* 4170** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement 4171** METHOD: sqlite3_stmt 4172** 4173** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the 4174** prepared statement S is an EXPLAIN statement, or 2 if the 4175** statement S is an EXPLAIN QUERY PLAN. 4176** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is 4177** an ordinary statement or a NULL pointer. 4178*/ 4179int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt); 4180 4181/* 4182** CAPI3REF: Determine If A Prepared Statement Has Been Reset 4183** METHOD: sqlite3_stmt 4184** 4185** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 4186** [prepared statement] S has been stepped at least once using 4187** [sqlite3_step(S)] but has neither run to completion (returned 4188** [SQLITE_DONE] from [sqlite3_step(S)]) nor 4189** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 4190** interface returns false if S is a NULL pointer. If S is not a 4191** NULL pointer and is not a pointer to a valid [prepared statement] 4192** object, then the behavior is undefined and probably undesirable. 4193** 4194** This interface can be used in combination [sqlite3_next_stmt()] 4195** to locate all prepared statements associated with a database 4196** connection that are in need of being reset. This can be used, 4197** for example, in diagnostic routines to search for prepared 4198** statements that are holding a transaction open. 4199*/ 4200int sqlite3_stmt_busy(sqlite3_stmt*); 4201 4202/* 4203** CAPI3REF: Dynamically Typed Value Object 4204** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 4205** 4206** SQLite uses the sqlite3_value object to represent all values 4207** that can be stored in a database table. SQLite uses dynamic typing 4208** for the values it stores. ^Values stored in sqlite3_value objects 4209** can be integers, floating point values, strings, BLOBs, or NULL. 4210** 4211** An sqlite3_value object may be either "protected" or "unprotected". 4212** Some interfaces require a protected sqlite3_value. Other interfaces 4213** will accept either a protected or an unprotected sqlite3_value. 4214** Every interface that accepts sqlite3_value arguments specifies 4215** whether or not it requires a protected sqlite3_value. The 4216** [sqlite3_value_dup()] interface can be used to construct a new 4217** protected sqlite3_value from an unprotected sqlite3_value. 4218** 4219** The terms "protected" and "unprotected" refer to whether or not 4220** a mutex is held. An internal mutex is held for a protected 4221** sqlite3_value object but no mutex is held for an unprotected 4222** sqlite3_value object. If SQLite is compiled to be single-threaded 4223** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 4224** or if SQLite is run in one of reduced mutex modes 4225** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 4226** then there is no distinction between protected and unprotected 4227** sqlite3_value objects and they can be used interchangeably. However, 4228** for maximum code portability it is recommended that applications 4229** still make the distinction between protected and unprotected 4230** sqlite3_value objects even when not strictly required. 4231** 4232** ^The sqlite3_value objects that are passed as parameters into the 4233** implementation of [application-defined SQL functions] are protected. 4234** ^The sqlite3_value object returned by 4235** [sqlite3_column_value()] is unprotected. 4236** Unprotected sqlite3_value objects may only be used as arguments 4237** to [sqlite3_result_value()], [sqlite3_bind_value()], and 4238** [sqlite3_value_dup()]. 4239** The [sqlite3_value_blob | sqlite3_value_type()] family of 4240** interfaces require protected sqlite3_value objects. 4241*/ 4242typedef struct sqlite3_value sqlite3_value; 4243 4244/* 4245** CAPI3REF: SQL Function Context Object 4246** 4247** The context in which an SQL function executes is stored in an 4248** sqlite3_context object. ^A pointer to an sqlite3_context object 4249** is always first parameter to [application-defined SQL functions]. 4250** The application-defined SQL function implementation will pass this 4251** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 4252** [sqlite3_aggregate_context()], [sqlite3_user_data()], 4253** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 4254** and/or [sqlite3_set_auxdata()]. 4255*/ 4256typedef struct sqlite3_context sqlite3_context; 4257 4258/* 4259** CAPI3REF: Binding Values To Prepared Statements 4260** KEYWORDS: {host parameter} {host parameters} {host parameter name} 4261** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 4262** METHOD: sqlite3_stmt 4263** 4264** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 4265** literals may be replaced by a [parameter] that matches one of following 4266** templates: 4267** 4268** <ul> 4269** <li> ? 4270** <li> ?NNN 4271** <li> :VVV 4272** <li> @VVV 4273** <li> $VVV 4274** </ul> 4275** 4276** In the templates above, NNN represents an integer literal, 4277** and VVV represents an alphanumeric identifier.)^ ^The values of these 4278** parameters (also called "host parameter names" or "SQL parameters") 4279** can be set using the sqlite3_bind_*() routines defined here. 4280** 4281** ^The first argument to the sqlite3_bind_*() routines is always 4282** a pointer to the [sqlite3_stmt] object returned from 4283** [sqlite3_prepare_v2()] or its variants. 4284** 4285** ^The second argument is the index of the SQL parameter to be set. 4286** ^The leftmost SQL parameter has an index of 1. ^When the same named 4287** SQL parameter is used more than once, second and subsequent 4288** occurrences have the same index as the first occurrence. 4289** ^The index for named parameters can be looked up using the 4290** [sqlite3_bind_parameter_index()] API if desired. ^The index 4291** for "?NNN" parameters is the value of NNN. 4292** ^The NNN value must be between 1 and the [sqlite3_limit()] 4293** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766). 4294** 4295** ^The third argument is the value to bind to the parameter. 4296** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4297** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 4298** is ignored and the end result is the same as sqlite3_bind_null(). 4299** ^If the third parameter to sqlite3_bind_text() is not NULL, then 4300** it should be a pointer to well-formed UTF8 text. 4301** ^If the third parameter to sqlite3_bind_text16() is not NULL, then 4302** it should be a pointer to well-formed UTF16 text. 4303** ^If the third parameter to sqlite3_bind_text64() is not NULL, then 4304** it should be a pointer to a well-formed unicode string that is 4305** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16 4306** otherwise. 4307** 4308** [[byte-order determination rules]] ^The byte-order of 4309** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF) 4310** found in first character, which is removed, or in the absence of a BOM 4311** the byte order is the native byte order of the host 4312** machine for sqlite3_bind_text16() or the byte order specified in 4313** the 6th parameter for sqlite3_bind_text64().)^ 4314** ^If UTF16 input text contains invalid unicode 4315** characters, then SQLite might change those invalid characters 4316** into the unicode replacement character: U+FFFD. 4317** 4318** ^(In those routines that have a fourth argument, its value is the 4319** number of bytes in the parameter. To be clear: the value is the 4320** number of <u>bytes</u> in the value, not the number of characters.)^ 4321** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4322** is negative, then the length of the string is 4323** the number of bytes up to the first zero terminator. 4324** If the fourth parameter to sqlite3_bind_blob() is negative, then 4325** the behavior is undefined. 4326** If a non-negative fourth parameter is provided to sqlite3_bind_text() 4327** or sqlite3_bind_text16() or sqlite3_bind_text64() then 4328** that parameter must be the byte offset 4329** where the NUL terminator would occur assuming the string were NUL 4330** terminated. If any NUL characters occurs at byte offsets less than 4331** the value of the fourth parameter then the resulting string value will 4332** contain embedded NULs. The result of expressions involving strings 4333** with embedded NULs is undefined. 4334** 4335** ^The fifth argument to the BLOB and string binding interfaces 4336** is a destructor used to dispose of the BLOB or 4337** string after SQLite has finished with it. ^The destructor is called 4338** to dispose of the BLOB or string even if the call to the bind API fails, 4339** except the destructor is not called if the third parameter is a NULL 4340** pointer or the fourth parameter is negative. 4341** ^If the fifth argument is 4342** the special value [SQLITE_STATIC], then SQLite assumes that the 4343** information is in static, unmanaged space and does not need to be freed. 4344** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 4345** SQLite makes its own private copy of the data immediately, before 4346** the sqlite3_bind_*() routine returns. 4347** 4348** ^The sixth argument to sqlite3_bind_text64() must be one of 4349** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 4350** to specify the encoding of the text in the third parameter. If 4351** the sixth argument to sqlite3_bind_text64() is not one of the 4352** allowed values shown above, or if the text encoding is different 4353** from the encoding specified by the sixth parameter, then the behavior 4354** is undefined. 4355** 4356** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 4357** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 4358** (just an integer to hold its size) while it is being processed. 4359** Zeroblobs are intended to serve as placeholders for BLOBs whose 4360** content is later written using 4361** [sqlite3_blob_open | incremental BLOB I/O] routines. 4362** ^A negative value for the zeroblob results in a zero-length BLOB. 4363** 4364** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 4365** [prepared statement] S to have an SQL value of NULL, but to also be 4366** associated with the pointer P of type T. ^D is either a NULL pointer or 4367** a pointer to a destructor function for P. ^SQLite will invoke the 4368** destructor D with a single argument of P when it is finished using 4369** P. The T parameter should be a static string, preferably a string 4370** literal. The sqlite3_bind_pointer() routine is part of the 4371** [pointer passing interface] added for SQLite 3.20.0. 4372** 4373** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 4374** for the [prepared statement] or with a prepared statement for which 4375** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 4376** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 4377** routine is passed a [prepared statement] that has been finalized, the 4378** result is undefined and probably harmful. 4379** 4380** ^Bindings are not cleared by the [sqlite3_reset()] routine. 4381** ^Unbound parameters are interpreted as NULL. 4382** 4383** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 4384** [error code] if anything goes wrong. 4385** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 4386** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 4387** [SQLITE_MAX_LENGTH]. 4388** ^[SQLITE_RANGE] is returned if the parameter 4389** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 4390** 4391** See also: [sqlite3_bind_parameter_count()], 4392** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 4393*/ 4394int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 4395int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 4396 void(*)(void*)); 4397int sqlite3_bind_double(sqlite3_stmt*, int, double); 4398int sqlite3_bind_int(sqlite3_stmt*, int, int); 4399int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 4400int sqlite3_bind_null(sqlite3_stmt*, int); 4401int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 4402int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 4403int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 4404 void(*)(void*), unsigned char encoding); 4405int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 4406int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 4407int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 4408int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 4409 4410/* 4411** CAPI3REF: Number Of SQL Parameters 4412** METHOD: sqlite3_stmt 4413** 4414** ^This routine can be used to find the number of [SQL parameters] 4415** in a [prepared statement]. SQL parameters are tokens of the 4416** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4417** placeholders for values that are [sqlite3_bind_blob | bound] 4418** to the parameters at a later time. 4419** 4420** ^(This routine actually returns the index of the largest (rightmost) 4421** parameter. For all forms except ?NNN, this will correspond to the 4422** number of unique parameters. If parameters of the ?NNN form are used, 4423** there may be gaps in the list.)^ 4424** 4425** See also: [sqlite3_bind_blob|sqlite3_bind()], 4426** [sqlite3_bind_parameter_name()], and 4427** [sqlite3_bind_parameter_index()]. 4428*/ 4429int sqlite3_bind_parameter_count(sqlite3_stmt*); 4430 4431/* 4432** CAPI3REF: Name Of A Host Parameter 4433** METHOD: sqlite3_stmt 4434** 4435** ^The sqlite3_bind_parameter_name(P,N) interface returns 4436** the name of the N-th [SQL parameter] in the [prepared statement] P. 4437** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4438** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4439** respectively. 4440** In other words, the initial ":" or "$" or "@" or "?" 4441** is included as part of the name.)^ 4442** ^Parameters of the form "?" without a following integer have no name 4443** and are referred to as "nameless" or "anonymous parameters". 4444** 4445** ^The first host parameter has an index of 1, not 0. 4446** 4447** ^If the value N is out of range or if the N-th parameter is 4448** nameless, then NULL is returned. ^The returned string is 4449** always in UTF-8 encoding even if the named parameter was 4450** originally specified as UTF-16 in [sqlite3_prepare16()], 4451** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4452** 4453** See also: [sqlite3_bind_blob|sqlite3_bind()], 4454** [sqlite3_bind_parameter_count()], and 4455** [sqlite3_bind_parameter_index()]. 4456*/ 4457const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4458 4459/* 4460** CAPI3REF: Index Of A Parameter With A Given Name 4461** METHOD: sqlite3_stmt 4462** 4463** ^Return the index of an SQL parameter given its name. ^The 4464** index value returned is suitable for use as the second 4465** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4466** is returned if no matching parameter is found. ^The parameter 4467** name must be given in UTF-8 even if the original statement 4468** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4469** [sqlite3_prepare16_v3()]. 4470** 4471** See also: [sqlite3_bind_blob|sqlite3_bind()], 4472** [sqlite3_bind_parameter_count()], and 4473** [sqlite3_bind_parameter_name()]. 4474*/ 4475int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4476 4477/* 4478** CAPI3REF: Reset All Bindings On A Prepared Statement 4479** METHOD: sqlite3_stmt 4480** 4481** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4482** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4483** ^Use this routine to reset all host parameters to NULL. 4484*/ 4485int sqlite3_clear_bindings(sqlite3_stmt*); 4486 4487/* 4488** CAPI3REF: Number Of Columns In A Result Set 4489** METHOD: sqlite3_stmt 4490** 4491** ^Return the number of columns in the result set returned by the 4492** [prepared statement]. ^If this routine returns 0, that means the 4493** [prepared statement] returns no data (for example an [UPDATE]). 4494** ^However, just because this routine returns a positive number does not 4495** mean that one or more rows of data will be returned. ^A SELECT statement 4496** will always have a positive sqlite3_column_count() but depending on the 4497** WHERE clause constraints and the table content, it might return no rows. 4498** 4499** See also: [sqlite3_data_count()] 4500*/ 4501int sqlite3_column_count(sqlite3_stmt *pStmt); 4502 4503/* 4504** CAPI3REF: Column Names In A Result Set 4505** METHOD: sqlite3_stmt 4506** 4507** ^These routines return the name assigned to a particular column 4508** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4509** interface returns a pointer to a zero-terminated UTF-8 string 4510** and sqlite3_column_name16() returns a pointer to a zero-terminated 4511** UTF-16 string. ^The first parameter is the [prepared statement] 4512** that implements the [SELECT] statement. ^The second parameter is the 4513** column number. ^The leftmost column is number 0. 4514** 4515** ^The returned string pointer is valid until either the [prepared statement] 4516** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4517** reprepared by the first call to [sqlite3_step()] for a particular run 4518** or until the next call to 4519** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4520** 4521** ^If sqlite3_malloc() fails during the processing of either routine 4522** (for example during a conversion from UTF-8 to UTF-16) then a 4523** NULL pointer is returned. 4524** 4525** ^The name of a result column is the value of the "AS" clause for 4526** that column, if there is an AS clause. If there is no AS clause 4527** then the name of the column is unspecified and may change from 4528** one release of SQLite to the next. 4529*/ 4530const char *sqlite3_column_name(sqlite3_stmt*, int N); 4531const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4532 4533/* 4534** CAPI3REF: Source Of Data In A Query Result 4535** METHOD: sqlite3_stmt 4536** 4537** ^These routines provide a means to determine the database, table, and 4538** table column that is the origin of a particular result column in 4539** [SELECT] statement. 4540** ^The name of the database or table or column can be returned as 4541** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4542** the database name, the _table_ routines return the table name, and 4543** the origin_ routines return the column name. 4544** ^The returned string is valid until the [prepared statement] is destroyed 4545** using [sqlite3_finalize()] or until the statement is automatically 4546** reprepared by the first call to [sqlite3_step()] for a particular run 4547** or until the same information is requested 4548** again in a different encoding. 4549** 4550** ^The names returned are the original un-aliased names of the 4551** database, table, and column. 4552** 4553** ^The first argument to these interfaces is a [prepared statement]. 4554** ^These functions return information about the Nth result column returned by 4555** the statement, where N is the second function argument. 4556** ^The left-most column is column 0 for these routines. 4557** 4558** ^If the Nth column returned by the statement is an expression or 4559** subquery and is not a column value, then all of these functions return 4560** NULL. ^These routines might also return NULL if a memory allocation error 4561** occurs. ^Otherwise, they return the name of the attached database, table, 4562** or column that query result column was extracted from. 4563** 4564** ^As with all other SQLite APIs, those whose names end with "16" return 4565** UTF-16 encoded strings and the other functions return UTF-8. 4566** 4567** ^These APIs are only available if the library was compiled with the 4568** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4569** 4570** If two or more threads call one or more 4571** [sqlite3_column_database_name | column metadata interfaces] 4572** for the same [prepared statement] and result column 4573** at the same time then the results are undefined. 4574*/ 4575const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4576const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4577const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4578const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4579const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4580const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4581 4582/* 4583** CAPI3REF: Declared Datatype Of A Query Result 4584** METHOD: sqlite3_stmt 4585** 4586** ^(The first parameter is a [prepared statement]. 4587** If this statement is a [SELECT] statement and the Nth column of the 4588** returned result set of that [SELECT] is a table column (not an 4589** expression or subquery) then the declared type of the table 4590** column is returned.)^ ^If the Nth column of the result set is an 4591** expression or subquery, then a NULL pointer is returned. 4592** ^The returned string is always UTF-8 encoded. 4593** 4594** ^(For example, given the database schema: 4595** 4596** CREATE TABLE t1(c1 VARIANT); 4597** 4598** and the following statement to be compiled: 4599** 4600** SELECT c1 + 1, c1 FROM t1; 4601** 4602** this routine would return the string "VARIANT" for the second result 4603** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4604** 4605** ^SQLite uses dynamic run-time typing. ^So just because a column 4606** is declared to contain a particular type does not mean that the 4607** data stored in that column is of the declared type. SQLite is 4608** strongly typed, but the typing is dynamic not static. ^Type 4609** is associated with individual values, not with the containers 4610** used to hold those values. 4611*/ 4612const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4613const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4614 4615/* 4616** CAPI3REF: Evaluate An SQL Statement 4617** METHOD: sqlite3_stmt 4618** 4619** After a [prepared statement] has been prepared using any of 4620** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4621** or [sqlite3_prepare16_v3()] or one of the legacy 4622** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4623** must be called one or more times to evaluate the statement. 4624** 4625** The details of the behavior of the sqlite3_step() interface depend 4626** on whether the statement was prepared using the newer "vX" interfaces 4627** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4628** [sqlite3_prepare16_v2()] or the older legacy 4629** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4630** new "vX" interface is recommended for new applications but the legacy 4631** interface will continue to be supported. 4632** 4633** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4634** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4635** ^With the "v2" interface, any of the other [result codes] or 4636** [extended result codes] might be returned as well. 4637** 4638** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4639** database locks it needs to do its job. ^If the statement is a [COMMIT] 4640** or occurs outside of an explicit transaction, then you can retry the 4641** statement. If the statement is not a [COMMIT] and occurs within an 4642** explicit transaction then you should rollback the transaction before 4643** continuing. 4644** 4645** ^[SQLITE_DONE] means that the statement has finished executing 4646** successfully. sqlite3_step() should not be called again on this virtual 4647** machine without first calling [sqlite3_reset()] to reset the virtual 4648** machine back to its initial state. 4649** 4650** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4651** is returned each time a new row of data is ready for processing by the 4652** caller. The values may be accessed using the [column access functions]. 4653** sqlite3_step() is called again to retrieve the next row of data. 4654** 4655** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4656** violation) has occurred. sqlite3_step() should not be called again on 4657** the VM. More information may be found by calling [sqlite3_errmsg()]. 4658** ^With the legacy interface, a more specific error code (for example, 4659** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4660** can be obtained by calling [sqlite3_reset()] on the 4661** [prepared statement]. ^In the "v2" interface, 4662** the more specific error code is returned directly by sqlite3_step(). 4663** 4664** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4665** Perhaps it was called on a [prepared statement] that has 4666** already been [sqlite3_finalize | finalized] or on one that had 4667** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4668** be the case that the same database connection is being used by two or 4669** more threads at the same moment in time. 4670** 4671** For all versions of SQLite up to and including 3.6.23.1, a call to 4672** [sqlite3_reset()] was required after sqlite3_step() returned anything 4673** other than [SQLITE_ROW] before any subsequent invocation of 4674** sqlite3_step(). Failure to reset the prepared statement using 4675** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4676** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4677** sqlite3_step() began 4678** calling [sqlite3_reset()] automatically in this circumstance rather 4679** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4680** break because any application that ever receives an SQLITE_MISUSE error 4681** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4682** can be used to restore the legacy behavior. 4683** 4684** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4685** API always returns a generic error code, [SQLITE_ERROR], following any 4686** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4687** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4688** specific [error codes] that better describes the error. 4689** We admit that this is a goofy design. The problem has been fixed 4690** with the "v2" interface. If you prepare all of your SQL statements 4691** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4692** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4693** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4694** then the more specific [error codes] are returned directly 4695** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4696*/ 4697int sqlite3_step(sqlite3_stmt*); 4698 4699/* 4700** CAPI3REF: Number of columns in a result set 4701** METHOD: sqlite3_stmt 4702** 4703** ^The sqlite3_data_count(P) interface returns the number of columns in the 4704** current row of the result set of [prepared statement] P. 4705** ^If prepared statement P does not have results ready to return 4706** (via calls to the [sqlite3_column_int | sqlite3_column()] family of 4707** interfaces) then sqlite3_data_count(P) returns 0. 4708** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4709** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4710** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4711** will return non-zero if previous call to [sqlite3_step](P) returned 4712** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4713** where it always returns zero since each step of that multi-step 4714** pragma returns 0 columns of data. 4715** 4716** See also: [sqlite3_column_count()] 4717*/ 4718int sqlite3_data_count(sqlite3_stmt *pStmt); 4719 4720/* 4721** CAPI3REF: Fundamental Datatypes 4722** KEYWORDS: SQLITE_TEXT 4723** 4724** ^(Every value in SQLite has one of five fundamental datatypes: 4725** 4726** <ul> 4727** <li> 64-bit signed integer 4728** <li> 64-bit IEEE floating point number 4729** <li> string 4730** <li> BLOB 4731** <li> NULL 4732** </ul>)^ 4733** 4734** These constants are codes for each of those types. 4735** 4736** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4737** for a completely different meaning. Software that links against both 4738** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4739** SQLITE_TEXT. 4740*/ 4741#define SQLITE_INTEGER 1 4742#define SQLITE_FLOAT 2 4743#define SQLITE_BLOB 4 4744#define SQLITE_NULL 5 4745#ifdef SQLITE_TEXT 4746# undef SQLITE_TEXT 4747#else 4748# define SQLITE_TEXT 3 4749#endif 4750#define SQLITE3_TEXT 3 4751 4752/* 4753** CAPI3REF: Result Values From A Query 4754** KEYWORDS: {column access functions} 4755** METHOD: sqlite3_stmt 4756** 4757** <b>Summary:</b> 4758** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4759** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4760** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4761** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4762** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4763** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4764** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4765** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4766** [sqlite3_value|unprotected sqlite3_value] object. 4767** <tr><td> <td> <td> 4768** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4769** or a UTF-8 TEXT result in bytes 4770** <tr><td><b>sqlite3_column_bytes16 </b> 4771** <td>→ <td>Size of UTF-16 4772** TEXT in bytes 4773** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4774** datatype of the result 4775** </table></blockquote> 4776** 4777** <b>Details:</b> 4778** 4779** ^These routines return information about a single column of the current 4780** result row of a query. ^In every case the first argument is a pointer 4781** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4782** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4783** and the second argument is the index of the column for which information 4784** should be returned. ^The leftmost column of the result set has the index 0. 4785** ^The number of columns in the result can be determined using 4786** [sqlite3_column_count()]. 4787** 4788** If the SQL statement does not currently point to a valid row, or if the 4789** column index is out of range, the result is undefined. 4790** These routines may only be called when the most recent call to 4791** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4792** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4793** If any of these routines are called after [sqlite3_reset()] or 4794** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4795** something other than [SQLITE_ROW], the results are undefined. 4796** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4797** are called from a different thread while any of these routines 4798** are pending, then the results are undefined. 4799** 4800** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4801** each return the value of a result column in a specific data format. If 4802** the result column is not initially in the requested format (for example, 4803** if the query returns an integer but the sqlite3_column_text() interface 4804** is used to extract the value) then an automatic type conversion is performed. 4805** 4806** ^The sqlite3_column_type() routine returns the 4807** [SQLITE_INTEGER | datatype code] for the initial data type 4808** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4809** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4810** The return value of sqlite3_column_type() can be used to decide which 4811** of the first six interface should be used to extract the column value. 4812** The value returned by sqlite3_column_type() is only meaningful if no 4813** automatic type conversions have occurred for the value in question. 4814** After a type conversion, the result of calling sqlite3_column_type() 4815** is undefined, though harmless. Future 4816** versions of SQLite may change the behavior of sqlite3_column_type() 4817** following a type conversion. 4818** 4819** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4820** or sqlite3_column_bytes16() interfaces can be used to determine the size 4821** of that BLOB or string. 4822** 4823** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4824** routine returns the number of bytes in that BLOB or string. 4825** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4826** the string to UTF-8 and then returns the number of bytes. 4827** ^If the result is a numeric value then sqlite3_column_bytes() uses 4828** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4829** the number of bytes in that string. 4830** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4831** 4832** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4833** routine returns the number of bytes in that BLOB or string. 4834** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4835** the string to UTF-16 and then returns the number of bytes. 4836** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4837** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4838** the number of bytes in that string. 4839** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4840** 4841** ^The values returned by [sqlite3_column_bytes()] and 4842** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4843** of the string. ^For clarity: the values returned by 4844** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4845** bytes in the string, not the number of characters. 4846** 4847** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4848** even empty strings, are always zero-terminated. ^The return 4849** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4850** 4851** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4852** [unprotected sqlite3_value] object. In a multithreaded environment, 4853** an unprotected sqlite3_value object may only be used safely with 4854** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4855** If the [unprotected sqlite3_value] object returned by 4856** [sqlite3_column_value()] is used in any other way, including calls 4857** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4858** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4859** Hence, the sqlite3_column_value() interface 4860** is normally only useful within the implementation of 4861** [application-defined SQL functions] or [virtual tables], not within 4862** top-level application code. 4863** 4864** The these routines may attempt to convert the datatype of the result. 4865** ^For example, if the internal representation is FLOAT and a text result 4866** is requested, [sqlite3_snprintf()] is used internally to perform the 4867** conversion automatically. ^(The following table details the conversions 4868** that are applied: 4869** 4870** <blockquote> 4871** <table border="1"> 4872** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4873** 4874** <tr><td> NULL <td> INTEGER <td> Result is 0 4875** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4876** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4877** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4878** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4879** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4880** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4881** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4882** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4883** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4884** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4885** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4886** <tr><td> TEXT <td> BLOB <td> No change 4887** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4888** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4889** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4890** </table> 4891** </blockquote>)^ 4892** 4893** Note that when type conversions occur, pointers returned by prior 4894** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4895** sqlite3_column_text16() may be invalidated. 4896** Type conversions and pointer invalidations might occur 4897** in the following cases: 4898** 4899** <ul> 4900** <li> The initial content is a BLOB and sqlite3_column_text() or 4901** sqlite3_column_text16() is called. A zero-terminator might 4902** need to be added to the string.</li> 4903** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4904** sqlite3_column_text16() is called. The content must be converted 4905** to UTF-16.</li> 4906** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4907** sqlite3_column_text() is called. The content must be converted 4908** to UTF-8.</li> 4909** </ul> 4910** 4911** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4912** not invalidate a prior pointer, though of course the content of the buffer 4913** that the prior pointer references will have been modified. Other kinds 4914** of conversion are done in place when it is possible, but sometimes they 4915** are not possible and in those cases prior pointers are invalidated. 4916** 4917** The safest policy is to invoke these routines 4918** in one of the following ways: 4919** 4920** <ul> 4921** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4922** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4923** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4924** </ul> 4925** 4926** In other words, you should call sqlite3_column_text(), 4927** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4928** into the desired format, then invoke sqlite3_column_bytes() or 4929** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4930** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4931** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4932** with calls to sqlite3_column_bytes(). 4933** 4934** ^The pointers returned are valid until a type conversion occurs as 4935** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4936** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4937** and BLOBs is freed automatically. Do not pass the pointers returned 4938** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4939** [sqlite3_free()]. 4940** 4941** As long as the input parameters are correct, these routines will only 4942** fail if an out-of-memory error occurs during a format conversion. 4943** Only the following subset of interfaces are subject to out-of-memory 4944** errors: 4945** 4946** <ul> 4947** <li> sqlite3_column_blob() 4948** <li> sqlite3_column_text() 4949** <li> sqlite3_column_text16() 4950** <li> sqlite3_column_bytes() 4951** <li> sqlite3_column_bytes16() 4952** </ul> 4953** 4954** If an out-of-memory error occurs, then the return value from these 4955** routines is the same as if the column had contained an SQL NULL value. 4956** Valid SQL NULL returns can be distinguished from out-of-memory errors 4957** by invoking the [sqlite3_errcode()] immediately after the suspect 4958** return value is obtained and before any 4959** other SQLite interface is called on the same [database connection]. 4960*/ 4961const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4962double sqlite3_column_double(sqlite3_stmt*, int iCol); 4963int sqlite3_column_int(sqlite3_stmt*, int iCol); 4964sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4965const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4966const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4967sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4968int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4969int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4970int sqlite3_column_type(sqlite3_stmt*, int iCol); 4971 4972/* 4973** CAPI3REF: Destroy A Prepared Statement Object 4974** DESTRUCTOR: sqlite3_stmt 4975** 4976** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4977** ^If the most recent evaluation of the statement encountered no errors 4978** or if the statement is never been evaluated, then sqlite3_finalize() returns 4979** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4980** sqlite3_finalize(S) returns the appropriate [error code] or 4981** [extended error code]. 4982** 4983** ^The sqlite3_finalize(S) routine can be called at any point during 4984** the life cycle of [prepared statement] S: 4985** before statement S is ever evaluated, after 4986** one or more calls to [sqlite3_reset()], or after any call 4987** to [sqlite3_step()] regardless of whether or not the statement has 4988** completed execution. 4989** 4990** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4991** 4992** The application must finalize every [prepared statement] in order to avoid 4993** resource leaks. It is a grievous error for the application to try to use 4994** a prepared statement after it has been finalized. Any use of a prepared 4995** statement after it has been finalized can result in undefined and 4996** undesirable behavior such as segfaults and heap corruption. 4997*/ 4998int sqlite3_finalize(sqlite3_stmt *pStmt); 4999 5000/* 5001** CAPI3REF: Reset A Prepared Statement Object 5002** METHOD: sqlite3_stmt 5003** 5004** The sqlite3_reset() function is called to reset a [prepared statement] 5005** object back to its initial state, ready to be re-executed. 5006** ^Any SQL statement variables that had values bound to them using 5007** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 5008** Use [sqlite3_clear_bindings()] to reset the bindings. 5009** 5010** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 5011** back to the beginning of its program. 5012** 5013** ^If the most recent call to [sqlite3_step(S)] for the 5014** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 5015** or if [sqlite3_step(S)] has never before been called on S, 5016** then [sqlite3_reset(S)] returns [SQLITE_OK]. 5017** 5018** ^If the most recent call to [sqlite3_step(S)] for the 5019** [prepared statement] S indicated an error, then 5020** [sqlite3_reset(S)] returns an appropriate [error code]. 5021** 5022** ^The [sqlite3_reset(S)] interface does not change the values 5023** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 5024*/ 5025int sqlite3_reset(sqlite3_stmt *pStmt); 5026 5027/* 5028** CAPI3REF: Create Or Redefine SQL Functions 5029** KEYWORDS: {function creation routines} 5030** METHOD: sqlite3 5031** 5032** ^These functions (collectively known as "function creation routines") 5033** are used to add SQL functions or aggregates or to redefine the behavior 5034** of existing SQL functions or aggregates. The only differences between 5035** the three "sqlite3_create_function*" routines are the text encoding 5036** expected for the second parameter (the name of the function being 5037** created) and the presence or absence of a destructor callback for 5038** the application data pointer. Function sqlite3_create_window_function() 5039** is similar, but allows the user to supply the extra callback functions 5040** needed by [aggregate window functions]. 5041** 5042** ^The first parameter is the [database connection] to which the SQL 5043** function is to be added. ^If an application uses more than one database 5044** connection then application-defined SQL functions must be added 5045** to each database connection separately. 5046** 5047** ^The second parameter is the name of the SQL function to be created or 5048** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 5049** representation, exclusive of the zero-terminator. ^Note that the name 5050** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 5051** ^Any attempt to create a function with a longer name 5052** will result in [SQLITE_MISUSE] being returned. 5053** 5054** ^The third parameter (nArg) 5055** is the number of arguments that the SQL function or 5056** aggregate takes. ^If this parameter is -1, then the SQL function or 5057** aggregate may take any number of arguments between 0 and the limit 5058** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 5059** parameter is less than -1 or greater than 127 then the behavior is 5060** undefined. 5061** 5062** ^The fourth parameter, eTextRep, specifies what 5063** [SQLITE_UTF8 | text encoding] this SQL function prefers for 5064** its parameters. The application should set this parameter to 5065** [SQLITE_UTF16LE] if the function implementation invokes 5066** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 5067** implementation invokes [sqlite3_value_text16be()] on an input, or 5068** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 5069** otherwise. ^The same SQL function may be registered multiple times using 5070** different preferred text encodings, with different implementations for 5071** each encoding. 5072** ^When multiple implementations of the same function are available, SQLite 5073** will pick the one that involves the least amount of data conversion. 5074** 5075** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 5076** to signal that the function will always return the same result given 5077** the same inputs within a single SQL statement. Most SQL functions are 5078** deterministic. The built-in [random()] SQL function is an example of a 5079** function that is not deterministic. The SQLite query planner is able to 5080** perform additional optimizations on deterministic functions, so use 5081** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 5082** 5083** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY] 5084** flag, which if present prevents the function from being invoked from 5085** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions, 5086** index expressions, or the WHERE clause of partial indexes. 5087** 5088** <span style="background-color:#ffff90;"> 5089** For best security, the [SQLITE_DIRECTONLY] flag is recommended for 5090** all application-defined SQL functions that do not need to be 5091** used inside of triggers, view, CHECK constraints, or other elements of 5092** the database schema. This flags is especially recommended for SQL 5093** functions that have side effects or reveal internal application state. 5094** Without this flag, an attacker might be able to modify the schema of 5095** a database file to include invocations of the function with parameters 5096** chosen by the attacker, which the application will then execute when 5097** the database file is opened and read. 5098** </span> 5099** 5100** ^(The fifth parameter is an arbitrary pointer. The implementation of the 5101** function can gain access to this pointer using [sqlite3_user_data()].)^ 5102** 5103** ^The sixth, seventh and eighth parameters passed to the three 5104** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are 5105** pointers to C-language functions that implement the SQL function or 5106** aggregate. ^A scalar SQL function requires an implementation of the xFunc 5107** callback only; NULL pointers must be passed as the xStep and xFinal 5108** parameters. ^An aggregate SQL function requires an implementation of xStep 5109** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 5110** SQL function or aggregate, pass NULL pointers for all three function 5111** callbacks. 5112** 5113** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue 5114** and xInverse) passed to sqlite3_create_window_function are pointers to 5115** C-language callbacks that implement the new function. xStep and xFinal 5116** must both be non-NULL. xValue and xInverse may either both be NULL, in 5117** which case a regular aggregate function is created, or must both be 5118** non-NULL, in which case the new function may be used as either an aggregate 5119** or aggregate window function. More details regarding the implementation 5120** of aggregate window functions are 5121** [user-defined window functions|available here]. 5122** 5123** ^(If the final parameter to sqlite3_create_function_v2() or 5124** sqlite3_create_window_function() is not NULL, then it is destructor for 5125** the application data pointer. The destructor is invoked when the function 5126** is deleted, either by being overloaded or when the database connection 5127** closes.)^ ^The destructor is also invoked if the call to 5128** sqlite3_create_function_v2() fails. ^When the destructor callback is 5129** invoked, it is passed a single argument which is a copy of the application 5130** data pointer which was the fifth parameter to sqlite3_create_function_v2(). 5131** 5132** ^It is permitted to register multiple implementations of the same 5133** functions with the same name but with either differing numbers of 5134** arguments or differing preferred text encodings. ^SQLite will use 5135** the implementation that most closely matches the way in which the 5136** SQL function is used. ^A function implementation with a non-negative 5137** nArg parameter is a better match than a function implementation with 5138** a negative nArg. ^A function where the preferred text encoding 5139** matches the database encoding is a better 5140** match than a function where the encoding is different. 5141** ^A function where the encoding difference is between UTF16le and UTF16be 5142** is a closer match than a function where the encoding difference is 5143** between UTF8 and UTF16. 5144** 5145** ^Built-in functions may be overloaded by new application-defined functions. 5146** 5147** ^An application-defined function is permitted to call other 5148** SQLite interfaces. However, such calls must not 5149** close the database connection nor finalize or reset the prepared 5150** statement in which the function is running. 5151*/ 5152int sqlite3_create_function( 5153 sqlite3 *db, 5154 const char *zFunctionName, 5155 int nArg, 5156 int eTextRep, 5157 void *pApp, 5158 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5159 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5160 void (*xFinal)(sqlite3_context*) 5161); 5162int sqlite3_create_function16( 5163 sqlite3 *db, 5164 const void *zFunctionName, 5165 int nArg, 5166 int eTextRep, 5167 void *pApp, 5168 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5169 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5170 void (*xFinal)(sqlite3_context*) 5171); 5172int sqlite3_create_function_v2( 5173 sqlite3 *db, 5174 const char *zFunctionName, 5175 int nArg, 5176 int eTextRep, 5177 void *pApp, 5178 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 5179 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5180 void (*xFinal)(sqlite3_context*), 5181 void(*xDestroy)(void*) 5182); 5183int sqlite3_create_window_function( 5184 sqlite3 *db, 5185 const char *zFunctionName, 5186 int nArg, 5187 int eTextRep, 5188 void *pApp, 5189 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 5190 void (*xFinal)(sqlite3_context*), 5191 void (*xValue)(sqlite3_context*), 5192 void (*xInverse)(sqlite3_context*,int,sqlite3_value**), 5193 void(*xDestroy)(void*) 5194); 5195 5196/* 5197** CAPI3REF: Text Encodings 5198** 5199** These constant define integer codes that represent the various 5200** text encodings supported by SQLite. 5201*/ 5202#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 5203#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 5204#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 5205#define SQLITE_UTF16 4 /* Use native byte order */ 5206#define SQLITE_ANY 5 /* Deprecated */ 5207#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 5208 5209/* 5210** CAPI3REF: Function Flags 5211** 5212** These constants may be ORed together with the 5213** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 5214** to [sqlite3_create_function()], [sqlite3_create_function16()], or 5215** [sqlite3_create_function_v2()]. 5216** 5217** <dl> 5218** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd> 5219** The SQLITE_DETERMINISTIC flag means that the new function always gives 5220** the same output when the input parameters are the same. 5221** The [abs|abs() function] is deterministic, for example, but 5222** [randomblob|randomblob()] is not. Functions must 5223** be deterministic in order to be used in certain contexts such as 5224** with the WHERE clause of [partial indexes] or in [generated columns]. 5225** SQLite might also optimize deterministic functions by factoring them 5226** out of inner loops. 5227** </dd> 5228** 5229** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd> 5230** The SQLITE_DIRECTONLY flag means that the function may only be invoked 5231** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in 5232** schema structures such as [CHECK constraints], [DEFAULT clauses], 5233** [expression indexes], [partial indexes], or [generated columns]. 5234** The SQLITE_DIRECTONLY flags is a security feature which is recommended 5235** for all [application-defined SQL functions], and especially for functions 5236** that have side-effects or that could potentially leak sensitive 5237** information. 5238** </dd> 5239** 5240** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd> 5241** The SQLITE_INNOCUOUS flag means that the function is unlikely 5242** to cause problems even if misused. An innocuous function should have 5243** no side effects and should not depend on any values other than its 5244** input parameters. The [abs|abs() function] is an example of an 5245** innocuous function. 5246** The [load_extension() SQL function] is not innocuous because of its 5247** side effects. 5248** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not 5249** exactly the same. The [random|random() function] is an example of a 5250** function that is innocuous but not deterministic. 5251** <p>Some heightened security settings 5252** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF]) 5253** disable the use of SQL functions inside views and triggers and in 5254** schema structures such as [CHECK constraints], [DEFAULT clauses], 5255** [expression indexes], [partial indexes], and [generated columns] unless 5256** the function is tagged with SQLITE_INNOCUOUS. Most built-in functions 5257** are innocuous. Developers are advised to avoid using the 5258** SQLITE_INNOCUOUS flag for application-defined functions unless the 5259** function has been carefully audited and found to be free of potentially 5260** security-adverse side-effects and information-leaks. 5261** </dd> 5262** 5263** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd> 5264** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call 5265** [sqlite3_value_subtype()] to inspect the sub-types of its arguments. 5266** Specifying this flag makes no difference for scalar or aggregate user 5267** functions. However, if it is not specified for a user-defined window 5268** function, then any sub-types belonging to arguments passed to the window 5269** function may be discarded before the window function is called (i.e. 5270** sqlite3_value_subtype() will always return 0). 5271** </dd> 5272** </dl> 5273*/ 5274#define SQLITE_DETERMINISTIC 0x000000800 5275#define SQLITE_DIRECTONLY 0x000080000 5276#define SQLITE_SUBTYPE 0x000100000 5277#define SQLITE_INNOCUOUS 0x000200000 5278 5279/* 5280** CAPI3REF: Deprecated Functions 5281** DEPRECATED 5282** 5283** These functions are [deprecated]. In order to maintain 5284** backwards compatibility with older code, these functions continue 5285** to be supported. However, new applications should avoid 5286** the use of these functions. To encourage programmers to avoid 5287** these functions, we will not explain what they do. 5288*/ 5289#ifndef SQLITE_OMIT_DEPRECATED 5290SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 5291SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 5292SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 5293SQLITE_DEPRECATED int sqlite3_global_recover(void); 5294SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 5295SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 5296 void*,sqlite3_int64); 5297#endif 5298 5299/* 5300** CAPI3REF: Obtaining SQL Values 5301** METHOD: sqlite3_value 5302** 5303** <b>Summary:</b> 5304** <blockquote><table border=0 cellpadding=0 cellspacing=0> 5305** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 5306** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 5307** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 5308** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 5309** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 5310** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 5311** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 5312** the native byteorder 5313** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 5314** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 5315** <tr><td> <td> <td> 5316** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 5317** or a UTF-8 TEXT in bytes 5318** <tr><td><b>sqlite3_value_bytes16 </b> 5319** <td>→ <td>Size of UTF-16 5320** TEXT in bytes 5321** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 5322** datatype of the value 5323** <tr><td><b>sqlite3_value_numeric_type </b> 5324** <td>→ <td>Best numeric datatype of the value 5325** <tr><td><b>sqlite3_value_nochange </b> 5326** <td>→ <td>True if the column is unchanged in an UPDATE 5327** against a virtual table. 5328** <tr><td><b>sqlite3_value_frombind </b> 5329** <td>→ <td>True if value originated from a [bound parameter] 5330** </table></blockquote> 5331** 5332** <b>Details:</b> 5333** 5334** These routines extract type, size, and content information from 5335** [protected sqlite3_value] objects. Protected sqlite3_value objects 5336** are used to pass parameter information into the functions that 5337** implement [application-defined SQL functions] and [virtual tables]. 5338** 5339** These routines work only with [protected sqlite3_value] objects. 5340** Any attempt to use these routines on an [unprotected sqlite3_value] 5341** is not threadsafe. 5342** 5343** ^These routines work just like the corresponding [column access functions] 5344** except that these routines take a single [protected sqlite3_value] object 5345** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 5346** 5347** ^The sqlite3_value_text16() interface extracts a UTF-16 string 5348** in the native byte-order of the host machine. ^The 5349** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 5350** extract UTF-16 strings as big-endian and little-endian respectively. 5351** 5352** ^If [sqlite3_value] object V was initialized 5353** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 5354** and if X and Y are strings that compare equal according to strcmp(X,Y), 5355** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 5356** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 5357** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5358** 5359** ^(The sqlite3_value_type(V) interface returns the 5360** [SQLITE_INTEGER | datatype code] for the initial datatype of the 5361** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 5362** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 5363** Other interfaces might change the datatype for an sqlite3_value object. 5364** For example, if the datatype is initially SQLITE_INTEGER and 5365** sqlite3_value_text(V) is called to extract a text value for that 5366** integer, then subsequent calls to sqlite3_value_type(V) might return 5367** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 5368** occurs is undefined and may change from one release of SQLite to the next. 5369** 5370** ^(The sqlite3_value_numeric_type() interface attempts to apply 5371** numeric affinity to the value. This means that an attempt is 5372** made to convert the value to an integer or floating point. If 5373** such a conversion is possible without loss of information (in other 5374** words, if the value is a string that looks like a number) 5375** then the conversion is performed. Otherwise no conversion occurs. 5376** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 5377** 5378** ^Within the [xUpdate] method of a [virtual table], the 5379** sqlite3_value_nochange(X) interface returns true if and only if 5380** the column corresponding to X is unchanged by the UPDATE operation 5381** that the xUpdate method call was invoked to implement and if 5382** and the prior [xColumn] method call that was invoked to extracted 5383** the value for that column returned without setting a result (probably 5384** because it queried [sqlite3_vtab_nochange()] and found that the column 5385** was unchanging). ^Within an [xUpdate] method, any value for which 5386** sqlite3_value_nochange(X) is true will in all other respects appear 5387** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 5388** than within an [xUpdate] method call for an UPDATE statement, then 5389** the return value is arbitrary and meaningless. 5390** 5391** ^The sqlite3_value_frombind(X) interface returns non-zero if the 5392** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()] 5393** interfaces. ^If X comes from an SQL literal value, or a table column, 5394** or an expression, then sqlite3_value_frombind(X) returns zero. 5395** 5396** Please pay particular attention to the fact that the pointer returned 5397** from [sqlite3_value_blob()], [sqlite3_value_text()], or 5398** [sqlite3_value_text16()] can be invalidated by a subsequent call to 5399** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 5400** or [sqlite3_value_text16()]. 5401** 5402** These routines must be called from the same thread as 5403** the SQL function that supplied the [sqlite3_value*] parameters. 5404** 5405** As long as the input parameter is correct, these routines can only 5406** fail if an out-of-memory error occurs during a format conversion. 5407** Only the following subset of interfaces are subject to out-of-memory 5408** errors: 5409** 5410** <ul> 5411** <li> sqlite3_value_blob() 5412** <li> sqlite3_value_text() 5413** <li> sqlite3_value_text16() 5414** <li> sqlite3_value_text16le() 5415** <li> sqlite3_value_text16be() 5416** <li> sqlite3_value_bytes() 5417** <li> sqlite3_value_bytes16() 5418** </ul> 5419** 5420** If an out-of-memory error occurs, then the return value from these 5421** routines is the same as if the column had contained an SQL NULL value. 5422** Valid SQL NULL returns can be distinguished from out-of-memory errors 5423** by invoking the [sqlite3_errcode()] immediately after the suspect 5424** return value is obtained and before any 5425** other SQLite interface is called on the same [database connection]. 5426*/ 5427const void *sqlite3_value_blob(sqlite3_value*); 5428double sqlite3_value_double(sqlite3_value*); 5429int sqlite3_value_int(sqlite3_value*); 5430sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 5431void *sqlite3_value_pointer(sqlite3_value*, const char*); 5432const unsigned char *sqlite3_value_text(sqlite3_value*); 5433const void *sqlite3_value_text16(sqlite3_value*); 5434const void *sqlite3_value_text16le(sqlite3_value*); 5435const void *sqlite3_value_text16be(sqlite3_value*); 5436int sqlite3_value_bytes(sqlite3_value*); 5437int sqlite3_value_bytes16(sqlite3_value*); 5438int sqlite3_value_type(sqlite3_value*); 5439int sqlite3_value_numeric_type(sqlite3_value*); 5440int sqlite3_value_nochange(sqlite3_value*); 5441int sqlite3_value_frombind(sqlite3_value*); 5442 5443/* 5444** CAPI3REF: Finding The Subtype Of SQL Values 5445** METHOD: sqlite3_value 5446** 5447** The sqlite3_value_subtype(V) function returns the subtype for 5448** an [application-defined SQL function] argument V. The subtype 5449** information can be used to pass a limited amount of context from 5450** one SQL function to another. Use the [sqlite3_result_subtype()] 5451** routine to set the subtype for the return value of an SQL function. 5452*/ 5453unsigned int sqlite3_value_subtype(sqlite3_value*); 5454 5455/* 5456** CAPI3REF: Copy And Free SQL Values 5457** METHOD: sqlite3_value 5458** 5459** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 5460** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 5461** is a [protected sqlite3_value] object even if the input is not. 5462** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 5463** memory allocation fails. 5464** 5465** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 5466** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 5467** then sqlite3_value_free(V) is a harmless no-op. 5468*/ 5469sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 5470void sqlite3_value_free(sqlite3_value*); 5471 5472/* 5473** CAPI3REF: Obtain Aggregate Function Context 5474** METHOD: sqlite3_context 5475** 5476** Implementations of aggregate SQL functions use this 5477** routine to allocate memory for storing their state. 5478** 5479** ^The first time the sqlite3_aggregate_context(C,N) routine is called 5480** for a particular aggregate function, SQLite allocates 5481** N bytes of memory, zeroes out that memory, and returns a pointer 5482** to the new memory. ^On second and subsequent calls to 5483** sqlite3_aggregate_context() for the same aggregate function instance, 5484** the same buffer is returned. Sqlite3_aggregate_context() is normally 5485** called once for each invocation of the xStep callback and then one 5486** last time when the xFinal callback is invoked. ^(When no rows match 5487** an aggregate query, the xStep() callback of the aggregate function 5488** implementation is never called and xFinal() is called exactly once. 5489** In those cases, sqlite3_aggregate_context() might be called for the 5490** first time from within xFinal().)^ 5491** 5492** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 5493** when first called if N is less than or equal to zero or if a memory 5494** allocate error occurs. 5495** 5496** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 5497** determined by the N parameter on first successful call. Changing the 5498** value of N in any subsequent call to sqlite3_aggregate_context() within 5499** the same aggregate function instance will not resize the memory 5500** allocation.)^ Within the xFinal callback, it is customary to set 5501** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 5502** pointless memory allocations occur. 5503** 5504** ^SQLite automatically frees the memory allocated by 5505** sqlite3_aggregate_context() when the aggregate query concludes. 5506** 5507** The first parameter must be a copy of the 5508** [sqlite3_context | SQL function context] that is the first parameter 5509** to the xStep or xFinal callback routine that implements the aggregate 5510** function. 5511** 5512** This routine must be called from the same thread in which 5513** the aggregate SQL function is running. 5514*/ 5515void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 5516 5517/* 5518** CAPI3REF: User Data For Functions 5519** METHOD: sqlite3_context 5520** 5521** ^The sqlite3_user_data() interface returns a copy of 5522** the pointer that was the pUserData parameter (the 5th parameter) 5523** of the [sqlite3_create_function()] 5524** and [sqlite3_create_function16()] routines that originally 5525** registered the application defined function. 5526** 5527** This routine must be called from the same thread in which 5528** the application-defined function is running. 5529*/ 5530void *sqlite3_user_data(sqlite3_context*); 5531 5532/* 5533** CAPI3REF: Database Connection For Functions 5534** METHOD: sqlite3_context 5535** 5536** ^The sqlite3_context_db_handle() interface returns a copy of 5537** the pointer to the [database connection] (the 1st parameter) 5538** of the [sqlite3_create_function()] 5539** and [sqlite3_create_function16()] routines that originally 5540** registered the application defined function. 5541*/ 5542sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 5543 5544/* 5545** CAPI3REF: Function Auxiliary Data 5546** METHOD: sqlite3_context 5547** 5548** These functions may be used by (non-aggregate) SQL functions to 5549** associate metadata with argument values. If the same value is passed to 5550** multiple invocations of the same SQL function during query execution, under 5551** some circumstances the associated metadata may be preserved. An example 5552** of where this might be useful is in a regular-expression matching 5553** function. The compiled version of the regular expression can be stored as 5554** metadata associated with the pattern string. 5555** Then as long as the pattern string remains the same, 5556** the compiled regular expression can be reused on multiple 5557** invocations of the same function. 5558** 5559** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 5560** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 5561** value to the application-defined function. ^N is zero for the left-most 5562** function argument. ^If there is no metadata 5563** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 5564** returns a NULL pointer. 5565** 5566** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 5567** argument of the application-defined function. ^Subsequent 5568** calls to sqlite3_get_auxdata(C,N) return P from the most recent 5569** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5570** NULL if the metadata has been discarded. 5571** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5572** SQLite will invoke the destructor function X with parameter P exactly 5573** once, when the metadata is discarded. 5574** SQLite is free to discard the metadata at any time, including: <ul> 5575** <li> ^(when the corresponding function parameter changes)^, or 5576** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5577** SQL statement)^, or 5578** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5579** parameter)^, or 5580** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5581** allocation error occurs.)^ </ul> 5582** 5583** Note the last bullet in particular. The destructor X in 5584** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5585** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5586** should be called near the end of the function implementation and the 5587** function implementation should not make any use of P after 5588** sqlite3_set_auxdata() has been called. 5589** 5590** ^(In practice, metadata is preserved between function calls for 5591** function parameters that are compile-time constants, including literal 5592** values and [parameters] and expressions composed from the same.)^ 5593** 5594** The value of the N parameter to these interfaces should be non-negative. 5595** Future enhancements may make use of negative N values to define new 5596** kinds of function caching behavior. 5597** 5598** These routines must be called from the same thread in which 5599** the SQL function is running. 5600*/ 5601void *sqlite3_get_auxdata(sqlite3_context*, int N); 5602void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5603 5604 5605/* 5606** CAPI3REF: Constants Defining Special Destructor Behavior 5607** 5608** These are special values for the destructor that is passed in as the 5609** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5610** argument is SQLITE_STATIC, it means that the content pointer is constant 5611** and will never change. It does not need to be destroyed. ^The 5612** SQLITE_TRANSIENT value means that the content will likely change in 5613** the near future and that SQLite should make its own private copy of 5614** the content before returning. 5615** 5616** The typedef is necessary to work around problems in certain 5617** C++ compilers. 5618*/ 5619typedef void (*sqlite3_destructor_type)(void*); 5620#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5621#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5622 5623/* 5624** CAPI3REF: Setting The Result Of An SQL Function 5625** METHOD: sqlite3_context 5626** 5627** These routines are used by the xFunc or xFinal callbacks that 5628** implement SQL functions and aggregates. See 5629** [sqlite3_create_function()] and [sqlite3_create_function16()] 5630** for additional information. 5631** 5632** These functions work very much like the [parameter binding] family of 5633** functions used to bind values to host parameters in prepared statements. 5634** Refer to the [SQL parameter] documentation for additional information. 5635** 5636** ^The sqlite3_result_blob() interface sets the result from 5637** an application-defined function to be the BLOB whose content is pointed 5638** to by the second parameter and which is N bytes long where N is the 5639** third parameter. 5640** 5641** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5642** interfaces set the result of the application-defined function to be 5643** a BLOB containing all zero bytes and N bytes in size. 5644** 5645** ^The sqlite3_result_double() interface sets the result from 5646** an application-defined function to be a floating point value specified 5647** by its 2nd argument. 5648** 5649** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5650** cause the implemented SQL function to throw an exception. 5651** ^SQLite uses the string pointed to by the 5652** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5653** as the text of an error message. ^SQLite interprets the error 5654** message string from sqlite3_result_error() as UTF-8. ^SQLite 5655** interprets the string from sqlite3_result_error16() as UTF-16 using 5656** the same [byte-order determination rules] as [sqlite3_bind_text16()]. 5657** ^If the third parameter to sqlite3_result_error() 5658** or sqlite3_result_error16() is negative then SQLite takes as the error 5659** message all text up through the first zero character. 5660** ^If the third parameter to sqlite3_result_error() or 5661** sqlite3_result_error16() is non-negative then SQLite takes that many 5662** bytes (not characters) from the 2nd parameter as the error message. 5663** ^The sqlite3_result_error() and sqlite3_result_error16() 5664** routines make a private copy of the error message text before 5665** they return. Hence, the calling function can deallocate or 5666** modify the text after they return without harm. 5667** ^The sqlite3_result_error_code() function changes the error code 5668** returned by SQLite as a result of an error in a function. ^By default, 5669** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5670** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5671** 5672** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5673** error indicating that a string or BLOB is too long to represent. 5674** 5675** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5676** error indicating that a memory allocation failed. 5677** 5678** ^The sqlite3_result_int() interface sets the return value 5679** of the application-defined function to be the 32-bit signed integer 5680** value given in the 2nd argument. 5681** ^The sqlite3_result_int64() interface sets the return value 5682** of the application-defined function to be the 64-bit signed integer 5683** value given in the 2nd argument. 5684** 5685** ^The sqlite3_result_null() interface sets the return value 5686** of the application-defined function to be NULL. 5687** 5688** ^The sqlite3_result_text(), sqlite3_result_text16(), 5689** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5690** set the return value of the application-defined function to be 5691** a text string which is represented as UTF-8, UTF-16 native byte order, 5692** UTF-16 little endian, or UTF-16 big endian, respectively. 5693** ^The sqlite3_result_text64() interface sets the return value of an 5694** application-defined function to be a text string in an encoding 5695** specified by the fifth (and last) parameter, which must be one 5696** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5697** ^SQLite takes the text result from the application from 5698** the 2nd parameter of the sqlite3_result_text* interfaces. 5699** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5700** is negative, then SQLite takes result text from the 2nd parameter 5701** through the first zero character. 5702** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5703** is non-negative, then as many bytes (not characters) of the text 5704** pointed to by the 2nd parameter are taken as the application-defined 5705** function result. If the 3rd parameter is non-negative, then it 5706** must be the byte offset into the string where the NUL terminator would 5707** appear if the string where NUL terminated. If any NUL characters occur 5708** in the string at a byte offset that is less than the value of the 3rd 5709** parameter, then the resulting string will contain embedded NULs and the 5710** result of expressions operating on strings with embedded NULs is undefined. 5711** ^If the 4th parameter to the sqlite3_result_text* interfaces 5712** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5713** function as the destructor on the text or BLOB result when it has 5714** finished using that result. 5715** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5716** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5717** assumes that the text or BLOB result is in constant space and does not 5718** copy the content of the parameter nor call a destructor on the content 5719** when it has finished using that result. 5720** ^If the 4th parameter to the sqlite3_result_text* interfaces 5721** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5722** then SQLite makes a copy of the result into space obtained 5723** from [sqlite3_malloc()] before it returns. 5724** 5725** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and 5726** sqlite3_result_text16be() routines, and for sqlite3_result_text64() 5727** when the encoding is not UTF8, if the input UTF16 begins with a 5728** byte-order mark (BOM, U+FEFF) then the BOM is removed from the 5729** string and the rest of the string is interpreted according to the 5730** byte-order specified by the BOM. ^The byte-order specified by 5731** the BOM at the beginning of the text overrides the byte-order 5732** specified by the interface procedure. ^So, for example, if 5733** sqlite3_result_text16le() is invoked with text that begins 5734** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the 5735** first two bytes of input are skipped and the remaining input 5736** is interpreted as UTF16BE text. 5737** 5738** ^For UTF16 input text to the sqlite3_result_text16(), 5739** sqlite3_result_text16be(), sqlite3_result_text16le(), and 5740** sqlite3_result_text64() routines, if the text contains invalid 5741** UTF16 characters, the invalid characters might be converted 5742** into the unicode replacement character, U+FFFD. 5743** 5744** ^The sqlite3_result_value() interface sets the result of 5745** the application-defined function to be a copy of the 5746** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5747** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5748** so that the [sqlite3_value] specified in the parameter may change or 5749** be deallocated after sqlite3_result_value() returns without harm. 5750** ^A [protected sqlite3_value] object may always be used where an 5751** [unprotected sqlite3_value] object is required, so either 5752** kind of [sqlite3_value] object can be used with this interface. 5753** 5754** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5755** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5756** also associates the host-language pointer P or type T with that 5757** NULL value such that the pointer can be retrieved within an 5758** [application-defined SQL function] using [sqlite3_value_pointer()]. 5759** ^If the D parameter is not NULL, then it is a pointer to a destructor 5760** for the P parameter. ^SQLite invokes D with P as its only argument 5761** when SQLite is finished with P. The T parameter should be a static 5762** string and preferably a string literal. The sqlite3_result_pointer() 5763** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5764** 5765** If these routines are called from within the different thread 5766** than the one containing the application-defined function that received 5767** the [sqlite3_context] pointer, the results are undefined. 5768*/ 5769void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5770void sqlite3_result_blob64(sqlite3_context*,const void*, 5771 sqlite3_uint64,void(*)(void*)); 5772void sqlite3_result_double(sqlite3_context*, double); 5773void sqlite3_result_error(sqlite3_context*, const char*, int); 5774void sqlite3_result_error16(sqlite3_context*, const void*, int); 5775void sqlite3_result_error_toobig(sqlite3_context*); 5776void sqlite3_result_error_nomem(sqlite3_context*); 5777void sqlite3_result_error_code(sqlite3_context*, int); 5778void sqlite3_result_int(sqlite3_context*, int); 5779void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5780void sqlite3_result_null(sqlite3_context*); 5781void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5782void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5783 void(*)(void*), unsigned char encoding); 5784void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5785void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5786void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5787void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5788void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5789void sqlite3_result_zeroblob(sqlite3_context*, int n); 5790int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5791 5792 5793/* 5794** CAPI3REF: Setting The Subtype Of An SQL Function 5795** METHOD: sqlite3_context 5796** 5797** The sqlite3_result_subtype(C,T) function causes the subtype of 5798** the result from the [application-defined SQL function] with 5799** [sqlite3_context] C to be the value T. Only the lower 8 bits 5800** of the subtype T are preserved in current versions of SQLite; 5801** higher order bits are discarded. 5802** The number of subtype bytes preserved by SQLite might increase 5803** in future releases of SQLite. 5804*/ 5805void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5806 5807/* 5808** CAPI3REF: Define New Collating Sequences 5809** METHOD: sqlite3 5810** 5811** ^These functions add, remove, or modify a [collation] associated 5812** with the [database connection] specified as the first argument. 5813** 5814** ^The name of the collation is a UTF-8 string 5815** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5816** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5817** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5818** considered to be the same name. 5819** 5820** ^(The third argument (eTextRep) must be one of the constants: 5821** <ul> 5822** <li> [SQLITE_UTF8], 5823** <li> [SQLITE_UTF16LE], 5824** <li> [SQLITE_UTF16BE], 5825** <li> [SQLITE_UTF16], or 5826** <li> [SQLITE_UTF16_ALIGNED]. 5827** </ul>)^ 5828** ^The eTextRep argument determines the encoding of strings passed 5829** to the collating function callback, xCompare. 5830** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5831** force strings to be UTF16 with native byte order. 5832** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5833** on an even byte address. 5834** 5835** ^The fourth argument, pArg, is an application data pointer that is passed 5836** through as the first argument to the collating function callback. 5837** 5838** ^The fifth argument, xCompare, is a pointer to the collating function. 5839** ^Multiple collating functions can be registered using the same name but 5840** with different eTextRep parameters and SQLite will use whichever 5841** function requires the least amount of data transformation. 5842** ^If the xCompare argument is NULL then the collating function is 5843** deleted. ^When all collating functions having the same name are deleted, 5844** that collation is no longer usable. 5845** 5846** ^The collating function callback is invoked with a copy of the pArg 5847** application data pointer and with two strings in the encoding specified 5848** by the eTextRep argument. The two integer parameters to the collating 5849** function callback are the length of the two strings, in bytes. The collating 5850** function must return an integer that is negative, zero, or positive 5851** if the first string is less than, equal to, or greater than the second, 5852** respectively. A collating function must always return the same answer 5853** given the same inputs. If two or more collating functions are registered 5854** to the same collation name (using different eTextRep values) then all 5855** must give an equivalent answer when invoked with equivalent strings. 5856** The collating function must obey the following properties for all 5857** strings A, B, and C: 5858** 5859** <ol> 5860** <li> If A==B then B==A. 5861** <li> If A==B and B==C then A==C. 5862** <li> If A<B THEN B>A. 5863** <li> If A<B and B<C then A<C. 5864** </ol> 5865** 5866** If a collating function fails any of the above constraints and that 5867** collating function is registered and used, then the behavior of SQLite 5868** is undefined. 5869** 5870** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5871** with the addition that the xDestroy callback is invoked on pArg when 5872** the collating function is deleted. 5873** ^Collating functions are deleted when they are overridden by later 5874** calls to the collation creation functions or when the 5875** [database connection] is closed using [sqlite3_close()]. 5876** 5877** ^The xDestroy callback is <u>not</u> called if the 5878** sqlite3_create_collation_v2() function fails. Applications that invoke 5879** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5880** check the return code and dispose of the application data pointer 5881** themselves rather than expecting SQLite to deal with it for them. 5882** This is different from every other SQLite interface. The inconsistency 5883** is unfortunate but cannot be changed without breaking backwards 5884** compatibility. 5885** 5886** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5887*/ 5888int sqlite3_create_collation( 5889 sqlite3*, 5890 const char *zName, 5891 int eTextRep, 5892 void *pArg, 5893 int(*xCompare)(void*,int,const void*,int,const void*) 5894); 5895int sqlite3_create_collation_v2( 5896 sqlite3*, 5897 const char *zName, 5898 int eTextRep, 5899 void *pArg, 5900 int(*xCompare)(void*,int,const void*,int,const void*), 5901 void(*xDestroy)(void*) 5902); 5903int sqlite3_create_collation16( 5904 sqlite3*, 5905 const void *zName, 5906 int eTextRep, 5907 void *pArg, 5908 int(*xCompare)(void*,int,const void*,int,const void*) 5909); 5910 5911/* 5912** CAPI3REF: Collation Needed Callbacks 5913** METHOD: sqlite3 5914** 5915** ^To avoid having to register all collation sequences before a database 5916** can be used, a single callback function may be registered with the 5917** [database connection] to be invoked whenever an undefined collation 5918** sequence is required. 5919** 5920** ^If the function is registered using the sqlite3_collation_needed() API, 5921** then it is passed the names of undefined collation sequences as strings 5922** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5923** the names are passed as UTF-16 in machine native byte order. 5924** ^A call to either function replaces the existing collation-needed callback. 5925** 5926** ^(When the callback is invoked, the first argument passed is a copy 5927** of the second argument to sqlite3_collation_needed() or 5928** sqlite3_collation_needed16(). The second argument is the database 5929** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5930** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5931** sequence function required. The fourth parameter is the name of the 5932** required collation sequence.)^ 5933** 5934** The callback function should register the desired collation using 5935** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5936** [sqlite3_create_collation_v2()]. 5937*/ 5938int sqlite3_collation_needed( 5939 sqlite3*, 5940 void*, 5941 void(*)(void*,sqlite3*,int eTextRep,const char*) 5942); 5943int sqlite3_collation_needed16( 5944 sqlite3*, 5945 void*, 5946 void(*)(void*,sqlite3*,int eTextRep,const void*) 5947); 5948 5949#ifdef SQLITE_ENABLE_CEROD 5950/* 5951** Specify the activation key for a CEROD database. Unless 5952** activated, none of the CEROD routines will work. 5953*/ 5954void sqlite3_activate_cerod( 5955 const char *zPassPhrase /* Activation phrase */ 5956); 5957#endif 5958 5959/* 5960** CAPI3REF: Suspend Execution For A Short Time 5961** 5962** The sqlite3_sleep() function causes the current thread to suspend execution 5963** for at least a number of milliseconds specified in its parameter. 5964** 5965** If the operating system does not support sleep requests with 5966** millisecond time resolution, then the time will be rounded up to 5967** the nearest second. The number of milliseconds of sleep actually 5968** requested from the operating system is returned. 5969** 5970** ^SQLite implements this interface by calling the xSleep() 5971** method of the default [sqlite3_vfs] object. If the xSleep() method 5972** of the default VFS is not implemented correctly, or not implemented at 5973** all, then the behavior of sqlite3_sleep() may deviate from the description 5974** in the previous paragraphs. 5975*/ 5976int sqlite3_sleep(int); 5977 5978/* 5979** CAPI3REF: Name Of The Folder Holding Temporary Files 5980** 5981** ^(If this global variable is made to point to a string which is 5982** the name of a folder (a.k.a. directory), then all temporary files 5983** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5984** will be placed in that directory.)^ ^If this variable 5985** is a NULL pointer, then SQLite performs a search for an appropriate 5986** temporary file directory. 5987** 5988** Applications are strongly discouraged from using this global variable. 5989** It is required to set a temporary folder on Windows Runtime (WinRT). 5990** But for all other platforms, it is highly recommended that applications 5991** neither read nor write this variable. This global variable is a relic 5992** that exists for backwards compatibility of legacy applications and should 5993** be avoided in new projects. 5994** 5995** It is not safe to read or modify this variable in more than one 5996** thread at a time. It is not safe to read or modify this variable 5997** if a [database connection] is being used at the same time in a separate 5998** thread. 5999** It is intended that this variable be set once 6000** as part of process initialization and before any SQLite interface 6001** routines have been called and that this variable remain unchanged 6002** thereafter. 6003** 6004** ^The [temp_store_directory pragma] may modify this variable and cause 6005** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6006** the [temp_store_directory pragma] always assumes that any string 6007** that this variable points to is held in memory obtained from 6008** [sqlite3_malloc] and the pragma may attempt to free that memory 6009** using [sqlite3_free]. 6010** Hence, if this variable is modified directly, either it should be 6011** made NULL or made to point to memory obtained from [sqlite3_malloc] 6012** or else the use of the [temp_store_directory pragma] should be avoided. 6013** Except when requested by the [temp_store_directory pragma], SQLite 6014** does not free the memory that sqlite3_temp_directory points to. If 6015** the application wants that memory to be freed, it must do 6016** so itself, taking care to only do so after all [database connection] 6017** objects have been destroyed. 6018** 6019** <b>Note to Windows Runtime users:</b> The temporary directory must be set 6020** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 6021** features that require the use of temporary files may fail. Here is an 6022** example of how to do this using C++ with the Windows Runtime: 6023** 6024** <blockquote><pre> 6025** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 6026** TemporaryFolder->Path->Data(); 6027** char zPathBuf[MAX_PATH + 1]; 6028** memset(zPathBuf, 0, sizeof(zPathBuf)); 6029** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 6030** NULL, NULL); 6031** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 6032** </pre></blockquote> 6033*/ 6034SQLITE_EXTERN char *sqlite3_temp_directory; 6035 6036/* 6037** CAPI3REF: Name Of The Folder Holding Database Files 6038** 6039** ^(If this global variable is made to point to a string which is 6040** the name of a folder (a.k.a. directory), then all database files 6041** specified with a relative pathname and created or accessed by 6042** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 6043** to be relative to that directory.)^ ^If this variable is a NULL 6044** pointer, then SQLite assumes that all database files specified 6045** with a relative pathname are relative to the current directory 6046** for the process. Only the windows VFS makes use of this global 6047** variable; it is ignored by the unix VFS. 6048** 6049** Changing the value of this variable while a database connection is 6050** open can result in a corrupt database. 6051** 6052** It is not safe to read or modify this variable in more than one 6053** thread at a time. It is not safe to read or modify this variable 6054** if a [database connection] is being used at the same time in a separate 6055** thread. 6056** It is intended that this variable be set once 6057** as part of process initialization and before any SQLite interface 6058** routines have been called and that this variable remain unchanged 6059** thereafter. 6060** 6061** ^The [data_store_directory pragma] may modify this variable and cause 6062** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 6063** the [data_store_directory pragma] always assumes that any string 6064** that this variable points to is held in memory obtained from 6065** [sqlite3_malloc] and the pragma may attempt to free that memory 6066** using [sqlite3_free]. 6067** Hence, if this variable is modified directly, either it should be 6068** made NULL or made to point to memory obtained from [sqlite3_malloc] 6069** or else the use of the [data_store_directory pragma] should be avoided. 6070*/ 6071SQLITE_EXTERN char *sqlite3_data_directory; 6072 6073/* 6074** CAPI3REF: Win32 Specific Interface 6075** 6076** These interfaces are available only on Windows. The 6077** [sqlite3_win32_set_directory] interface is used to set the value associated 6078** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to 6079** zValue, depending on the value of the type parameter. The zValue parameter 6080** should be NULL to cause the previous value to be freed via [sqlite3_free]; 6081** a non-NULL value will be copied into memory obtained from [sqlite3_malloc] 6082** prior to being used. The [sqlite3_win32_set_directory] interface returns 6083** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported, 6084** or [SQLITE_NOMEM] if memory could not be allocated. The value of the 6085** [sqlite3_data_directory] variable is intended to act as a replacement for 6086** the current directory on the sub-platforms of Win32 where that concept is 6087** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and 6088** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the 6089** sqlite3_win32_set_directory interface except the string parameter must be 6090** UTF-8 or UTF-16, respectively. 6091*/ 6092int sqlite3_win32_set_directory( 6093 unsigned long type, /* Identifier for directory being set or reset */ 6094 void *zValue /* New value for directory being set or reset */ 6095); 6096int sqlite3_win32_set_directory8(unsigned long type, const char *zValue); 6097int sqlite3_win32_set_directory16(unsigned long type, const void *zValue); 6098 6099/* 6100** CAPI3REF: Win32 Directory Types 6101** 6102** These macros are only available on Windows. They define the allowed values 6103** for the type argument to the [sqlite3_win32_set_directory] interface. 6104*/ 6105#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1 6106#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2 6107 6108/* 6109** CAPI3REF: Test For Auto-Commit Mode 6110** KEYWORDS: {autocommit mode} 6111** METHOD: sqlite3 6112** 6113** ^The sqlite3_get_autocommit() interface returns non-zero or 6114** zero if the given database connection is or is not in autocommit mode, 6115** respectively. ^Autocommit mode is on by default. 6116** ^Autocommit mode is disabled by a [BEGIN] statement. 6117** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 6118** 6119** If certain kinds of errors occur on a statement within a multi-statement 6120** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 6121** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 6122** transaction might be rolled back automatically. The only way to 6123** find out whether SQLite automatically rolled back the transaction after 6124** an error is to use this function. 6125** 6126** If another thread changes the autocommit status of the database 6127** connection while this routine is running, then the return value 6128** is undefined. 6129*/ 6130int sqlite3_get_autocommit(sqlite3*); 6131 6132/* 6133** CAPI3REF: Find The Database Handle Of A Prepared Statement 6134** METHOD: sqlite3_stmt 6135** 6136** ^The sqlite3_db_handle interface returns the [database connection] handle 6137** to which a [prepared statement] belongs. ^The [database connection] 6138** returned by sqlite3_db_handle is the same [database connection] 6139** that was the first argument 6140** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 6141** create the statement in the first place. 6142*/ 6143sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 6144 6145/* 6146** CAPI3REF: Return The Filename For A Database Connection 6147** METHOD: sqlite3 6148** 6149** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename 6150** associated with database N of connection D. 6151** ^If there is no attached database N on the database 6152** connection D, or if database N is a temporary or in-memory database, then 6153** this function will return either a NULL pointer or an empty string. 6154** 6155** ^The string value returned by this routine is owned and managed by 6156** the database connection. ^The value will be valid until the database N 6157** is [DETACH]-ed or until the database connection closes. 6158** 6159** ^The filename returned by this function is the output of the 6160** xFullPathname method of the [VFS]. ^In other words, the filename 6161** will be an absolute pathname, even if the filename used 6162** to open the database originally was a URI or relative pathname. 6163** 6164** If the filename pointer returned by this routine is not NULL, then it 6165** can be used as the filename input parameter to these routines: 6166** <ul> 6167** <li> [sqlite3_uri_parameter()] 6168** <li> [sqlite3_uri_boolean()] 6169** <li> [sqlite3_uri_int64()] 6170** <li> [sqlite3_filename_database()] 6171** <li> [sqlite3_filename_journal()] 6172** <li> [sqlite3_filename_wal()] 6173** </ul> 6174*/ 6175const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 6176 6177/* 6178** CAPI3REF: Determine if a database is read-only 6179** METHOD: sqlite3 6180** 6181** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 6182** of connection D is read-only, 0 if it is read/write, or -1 if N is not 6183** the name of a database on connection D. 6184*/ 6185int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 6186 6187/* 6188** CAPI3REF: Find the next prepared statement 6189** METHOD: sqlite3 6190** 6191** ^This interface returns a pointer to the next [prepared statement] after 6192** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 6193** then this interface returns a pointer to the first prepared statement 6194** associated with the database connection pDb. ^If no prepared statement 6195** satisfies the conditions of this routine, it returns NULL. 6196** 6197** The [database connection] pointer D in a call to 6198** [sqlite3_next_stmt(D,S)] must refer to an open database 6199** connection and in particular must not be a NULL pointer. 6200*/ 6201sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 6202 6203/* 6204** CAPI3REF: Commit And Rollback Notification Callbacks 6205** METHOD: sqlite3 6206** 6207** ^The sqlite3_commit_hook() interface registers a callback 6208** function to be invoked whenever a transaction is [COMMIT | committed]. 6209** ^Any callback set by a previous call to sqlite3_commit_hook() 6210** for the same database connection is overridden. 6211** ^The sqlite3_rollback_hook() interface registers a callback 6212** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 6213** ^Any callback set by a previous call to sqlite3_rollback_hook() 6214** for the same database connection is overridden. 6215** ^The pArg argument is passed through to the callback. 6216** ^If the callback on a commit hook function returns non-zero, 6217** then the commit is converted into a rollback. 6218** 6219** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 6220** return the P argument from the previous call of the same function 6221** on the same [database connection] D, or NULL for 6222** the first call for each function on D. 6223** 6224** The commit and rollback hook callbacks are not reentrant. 6225** The callback implementation must not do anything that will modify 6226** the database connection that invoked the callback. Any actions 6227** to modify the database connection must be deferred until after the 6228** completion of the [sqlite3_step()] call that triggered the commit 6229** or rollback hook in the first place. 6230** Note that running any other SQL statements, including SELECT statements, 6231** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 6232** the database connections for the meaning of "modify" in this paragraph. 6233** 6234** ^Registering a NULL function disables the callback. 6235** 6236** ^When the commit hook callback routine returns zero, the [COMMIT] 6237** operation is allowed to continue normally. ^If the commit hook 6238** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 6239** ^The rollback hook is invoked on a rollback that results from a commit 6240** hook returning non-zero, just as it would be with any other rollback. 6241** 6242** ^For the purposes of this API, a transaction is said to have been 6243** rolled back if an explicit "ROLLBACK" statement is executed, or 6244** an error or constraint causes an implicit rollback to occur. 6245** ^The rollback callback is not invoked if a transaction is 6246** automatically rolled back because the database connection is closed. 6247** 6248** See also the [sqlite3_update_hook()] interface. 6249*/ 6250void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 6251void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 6252 6253/* 6254** CAPI3REF: Data Change Notification Callbacks 6255** METHOD: sqlite3 6256** 6257** ^The sqlite3_update_hook() interface registers a callback function 6258** with the [database connection] identified by the first argument 6259** to be invoked whenever a row is updated, inserted or deleted in 6260** a [rowid table]. 6261** ^Any callback set by a previous call to this function 6262** for the same database connection is overridden. 6263** 6264** ^The second argument is a pointer to the function to invoke when a 6265** row is updated, inserted or deleted in a rowid table. 6266** ^The first argument to the callback is a copy of the third argument 6267** to sqlite3_update_hook(). 6268** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 6269** or [SQLITE_UPDATE], depending on the operation that caused the callback 6270** to be invoked. 6271** ^The third and fourth arguments to the callback contain pointers to the 6272** database and table name containing the affected row. 6273** ^The final callback parameter is the [rowid] of the row. 6274** ^In the case of an update, this is the [rowid] after the update takes place. 6275** 6276** ^(The update hook is not invoked when internal system tables are 6277** modified (i.e. sqlite_master and sqlite_sequence).)^ 6278** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 6279** 6280** ^In the current implementation, the update hook 6281** is not invoked when conflicting rows are deleted because of an 6282** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 6283** invoked when rows are deleted using the [truncate optimization]. 6284** The exceptions defined in this paragraph might change in a future 6285** release of SQLite. 6286** 6287** The update hook implementation must not do anything that will modify 6288** the database connection that invoked the update hook. Any actions 6289** to modify the database connection must be deferred until after the 6290** completion of the [sqlite3_step()] call that triggered the update hook. 6291** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 6292** database connections for the meaning of "modify" in this paragraph. 6293** 6294** ^The sqlite3_update_hook(D,C,P) function 6295** returns the P argument from the previous call 6296** on the same [database connection] D, or NULL for 6297** the first call on D. 6298** 6299** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 6300** and [sqlite3_preupdate_hook()] interfaces. 6301*/ 6302void *sqlite3_update_hook( 6303 sqlite3*, 6304 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 6305 void* 6306); 6307 6308/* 6309** CAPI3REF: Enable Or Disable Shared Pager Cache 6310** 6311** ^(This routine enables or disables the sharing of the database cache 6312** and schema data structures between [database connection | connections] 6313** to the same database. Sharing is enabled if the argument is true 6314** and disabled if the argument is false.)^ 6315** 6316** ^Cache sharing is enabled and disabled for an entire process. 6317** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 6318** In prior versions of SQLite, 6319** sharing was enabled or disabled for each thread separately. 6320** 6321** ^(The cache sharing mode set by this interface effects all subsequent 6322** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 6323** Existing database connections continue to use the sharing mode 6324** that was in effect at the time they were opened.)^ 6325** 6326** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 6327** successfully. An [error code] is returned otherwise.)^ 6328** 6329** ^Shared cache is disabled by default. It is recommended that it stay 6330** that way. In other words, do not use this routine. This interface 6331** continues to be provided for historical compatibility, but its use is 6332** discouraged. Any use of shared cache is discouraged. If shared cache 6333** must be used, it is recommended that shared cache only be enabled for 6334** individual database connections using the [sqlite3_open_v2()] interface 6335** with the [SQLITE_OPEN_SHAREDCACHE] flag. 6336** 6337** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 6338** and will always return SQLITE_MISUSE. On those systems, 6339** shared cache mode should be enabled per-database connection via 6340** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 6341** 6342** This interface is threadsafe on processors where writing a 6343** 32-bit integer is atomic. 6344** 6345** See Also: [SQLite Shared-Cache Mode] 6346*/ 6347int sqlite3_enable_shared_cache(int); 6348 6349/* 6350** CAPI3REF: Attempt To Free Heap Memory 6351** 6352** ^The sqlite3_release_memory() interface attempts to free N bytes 6353** of heap memory by deallocating non-essential memory allocations 6354** held by the database library. Memory used to cache database 6355** pages to improve performance is an example of non-essential memory. 6356** ^sqlite3_release_memory() returns the number of bytes actually freed, 6357** which might be more or less than the amount requested. 6358** ^The sqlite3_release_memory() routine is a no-op returning zero 6359** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 6360** 6361** See also: [sqlite3_db_release_memory()] 6362*/ 6363int sqlite3_release_memory(int); 6364 6365/* 6366** CAPI3REF: Free Memory Used By A Database Connection 6367** METHOD: sqlite3 6368** 6369** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 6370** memory as possible from database connection D. Unlike the 6371** [sqlite3_release_memory()] interface, this interface is in effect even 6372** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 6373** omitted. 6374** 6375** See also: [sqlite3_release_memory()] 6376*/ 6377int sqlite3_db_release_memory(sqlite3*); 6378 6379/* 6380** CAPI3REF: Impose A Limit On Heap Size 6381** 6382** These interfaces impose limits on the amount of heap memory that will be 6383** by all database connections within a single process. 6384** 6385** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 6386** soft limit on the amount of heap memory that may be allocated by SQLite. 6387** ^SQLite strives to keep heap memory utilization below the soft heap 6388** limit by reducing the number of pages held in the page cache 6389** as heap memory usages approaches the limit. 6390** ^The soft heap limit is "soft" because even though SQLite strives to stay 6391** below the limit, it will exceed the limit rather than generate 6392** an [SQLITE_NOMEM] error. In other words, the soft heap limit 6393** is advisory only. 6394** 6395** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of 6396** N bytes on the amount of memory that will be allocated. ^The 6397** sqlite3_hard_heap_limit64(N) interface is similar to 6398** sqlite3_soft_heap_limit64(N) except that memory allocations will fail 6399** when the hard heap limit is reached. 6400** 6401** ^The return value from both sqlite3_soft_heap_limit64() and 6402** sqlite3_hard_heap_limit64() is the size of 6403** the heap limit prior to the call, or negative in the case of an 6404** error. ^If the argument N is negative 6405** then no change is made to the heap limit. Hence, the current 6406** size of heap limits can be determined by invoking 6407** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1). 6408** 6409** ^Setting the heap limits to zero disables the heap limiter mechanism. 6410** 6411** ^The soft heap limit may not be greater than the hard heap limit. 6412** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N) 6413** is invoked with a value of N that is greater than the hard heap limit, 6414** the the soft heap limit is set to the value of the hard heap limit. 6415** ^The soft heap limit is automatically enabled whenever the hard heap 6416** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and 6417** the soft heap limit is outside the range of 1..N, then the soft heap 6418** limit is set to N. ^Invoking sqlite3_soft_heap_limit64(0) when the 6419** hard heap limit is enabled makes the soft heap limit equal to the 6420** hard heap limit. 6421** 6422** The memory allocation limits can also be adjusted using 6423** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit]. 6424** 6425** ^(The heap limits are not enforced in the current implementation 6426** if one or more of following conditions are true: 6427** 6428** <ul> 6429** <li> The limit value is set to zero. 6430** <li> Memory accounting is disabled using a combination of the 6431** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 6432** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 6433** <li> An alternative page cache implementation is specified using 6434** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 6435** <li> The page cache allocates from its own memory pool supplied 6436** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 6437** from the heap. 6438** </ul>)^ 6439** 6440** The circumstances under which SQLite will enforce the heap limits may 6441** changes in future releases of SQLite. 6442*/ 6443sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 6444sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N); 6445 6446/* 6447** CAPI3REF: Deprecated Soft Heap Limit Interface 6448** DEPRECATED 6449** 6450** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 6451** interface. This routine is provided for historical compatibility 6452** only. All new applications should use the 6453** [sqlite3_soft_heap_limit64()] interface rather than this one. 6454*/ 6455SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 6456 6457 6458/* 6459** CAPI3REF: Extract Metadata About A Column Of A Table 6460** METHOD: sqlite3 6461** 6462** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 6463** information about column C of table T in database D 6464** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 6465** interface returns SQLITE_OK and fills in the non-NULL pointers in 6466** the final five arguments with appropriate values if the specified 6467** column exists. ^The sqlite3_table_column_metadata() interface returns 6468** SQLITE_ERROR if the specified column does not exist. 6469** ^If the column-name parameter to sqlite3_table_column_metadata() is a 6470** NULL pointer, then this routine simply checks for the existence of the 6471** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 6472** does not. If the table name parameter T in a call to 6473** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 6474** undefined behavior. 6475** 6476** ^The column is identified by the second, third and fourth parameters to 6477** this function. ^(The second parameter is either the name of the database 6478** (i.e. "main", "temp", or an attached database) containing the specified 6479** table or NULL.)^ ^If it is NULL, then all attached databases are searched 6480** for the table using the same algorithm used by the database engine to 6481** resolve unqualified table references. 6482** 6483** ^The third and fourth parameters to this function are the table and column 6484** name of the desired column, respectively. 6485** 6486** ^Metadata is returned by writing to the memory locations passed as the 5th 6487** and subsequent parameters to this function. ^Any of these arguments may be 6488** NULL, in which case the corresponding element of metadata is omitted. 6489** 6490** ^(<blockquote> 6491** <table border="1"> 6492** <tr><th> Parameter <th> Output<br>Type <th> Description 6493** 6494** <tr><td> 5th <td> const char* <td> Data type 6495** <tr><td> 6th <td> const char* <td> Name of default collation sequence 6496** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 6497** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 6498** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 6499** </table> 6500** </blockquote>)^ 6501** 6502** ^The memory pointed to by the character pointers returned for the 6503** declaration type and collation sequence is valid until the next 6504** call to any SQLite API function. 6505** 6506** ^If the specified table is actually a view, an [error code] is returned. 6507** 6508** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 6509** is not a [WITHOUT ROWID] table and an 6510** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 6511** parameters are set for the explicitly declared column. ^(If there is no 6512** [INTEGER PRIMARY KEY] column, then the outputs 6513** for the [rowid] are set as follows: 6514** 6515** <pre> 6516** data type: "INTEGER" 6517** collation sequence: "BINARY" 6518** not null: 0 6519** primary key: 1 6520** auto increment: 0 6521** </pre>)^ 6522** 6523** ^This function causes all database schemas to be read from disk and 6524** parsed, if that has not already been done, and returns an error if 6525** any errors are encountered while loading the schema. 6526*/ 6527int sqlite3_table_column_metadata( 6528 sqlite3 *db, /* Connection handle */ 6529 const char *zDbName, /* Database name or NULL */ 6530 const char *zTableName, /* Table name */ 6531 const char *zColumnName, /* Column name */ 6532 char const **pzDataType, /* OUTPUT: Declared data type */ 6533 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 6534 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 6535 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 6536 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 6537); 6538 6539/* 6540** CAPI3REF: Load An Extension 6541** METHOD: sqlite3 6542** 6543** ^This interface loads an SQLite extension library from the named file. 6544** 6545** ^The sqlite3_load_extension() interface attempts to load an 6546** [SQLite extension] library contained in the file zFile. If 6547** the file cannot be loaded directly, attempts are made to load 6548** with various operating-system specific extensions added. 6549** So for example, if "samplelib" cannot be loaded, then names like 6550** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 6551** be tried also. 6552** 6553** ^The entry point is zProc. 6554** ^(zProc may be 0, in which case SQLite will try to come up with an 6555** entry point name on its own. It first tries "sqlite3_extension_init". 6556** If that does not work, it constructs a name "sqlite3_X_init" where the 6557** X is consists of the lower-case equivalent of all ASCII alphabetic 6558** characters in the filename from the last "/" to the first following 6559** "." and omitting any initial "lib".)^ 6560** ^The sqlite3_load_extension() interface returns 6561** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 6562** ^If an error occurs and pzErrMsg is not 0, then the 6563** [sqlite3_load_extension()] interface shall attempt to 6564** fill *pzErrMsg with error message text stored in memory 6565** obtained from [sqlite3_malloc()]. The calling function 6566** should free this memory by calling [sqlite3_free()]. 6567** 6568** ^Extension loading must be enabled using 6569** [sqlite3_enable_load_extension()] or 6570** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 6571** prior to calling this API, 6572** otherwise an error will be returned. 6573** 6574** <b>Security warning:</b> It is recommended that the 6575** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 6576** interface. The use of the [sqlite3_enable_load_extension()] interface 6577** should be avoided. This will keep the SQL function [load_extension()] 6578** disabled and prevent SQL injections from giving attackers 6579** access to extension loading capabilities. 6580** 6581** See also the [load_extension() SQL function]. 6582*/ 6583int sqlite3_load_extension( 6584 sqlite3 *db, /* Load the extension into this database connection */ 6585 const char *zFile, /* Name of the shared library containing extension */ 6586 const char *zProc, /* Entry point. Derived from zFile if 0 */ 6587 char **pzErrMsg /* Put error message here if not 0 */ 6588); 6589 6590/* 6591** CAPI3REF: Enable Or Disable Extension Loading 6592** METHOD: sqlite3 6593** 6594** ^So as not to open security holes in older applications that are 6595** unprepared to deal with [extension loading], and as a means of disabling 6596** [extension loading] while evaluating user-entered SQL, the following API 6597** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 6598** 6599** ^Extension loading is off by default. 6600** ^Call the sqlite3_enable_load_extension() routine with onoff==1 6601** to turn extension loading on and call it with onoff==0 to turn 6602** it back off again. 6603** 6604** ^This interface enables or disables both the C-API 6605** [sqlite3_load_extension()] and the SQL function [load_extension()]. 6606** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 6607** to enable or disable only the C-API.)^ 6608** 6609** <b>Security warning:</b> It is recommended that extension loading 6610** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 6611** rather than this interface, so the [load_extension()] SQL function 6612** remains disabled. This will prevent SQL injections from giving attackers 6613** access to extension loading capabilities. 6614*/ 6615int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6616 6617/* 6618** CAPI3REF: Automatically Load Statically Linked Extensions 6619** 6620** ^This interface causes the xEntryPoint() function to be invoked for 6621** each new [database connection] that is created. The idea here is that 6622** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6623** that is to be automatically loaded into all new database connections. 6624** 6625** ^(Even though the function prototype shows that xEntryPoint() takes 6626** no arguments and returns void, SQLite invokes xEntryPoint() with three 6627** arguments and expects an integer result as if the signature of the 6628** entry point where as follows: 6629** 6630** <blockquote><pre> 6631** int xEntryPoint( 6632** sqlite3 *db, 6633** const char **pzErrMsg, 6634** const struct sqlite3_api_routines *pThunk 6635** ); 6636** </pre></blockquote>)^ 6637** 6638** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6639** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6640** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6641** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6642** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6643** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6644** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6645** 6646** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6647** on the list of automatic extensions is a harmless no-op. ^No entry point 6648** will be called more than once for each database connection that is opened. 6649** 6650** See also: [sqlite3_reset_auto_extension()] 6651** and [sqlite3_cancel_auto_extension()] 6652*/ 6653int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6654 6655/* 6656** CAPI3REF: Cancel Automatic Extension Loading 6657** 6658** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6659** initialization routine X that was registered using a prior call to 6660** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6661** routine returns 1 if initialization routine X was successfully 6662** unregistered and it returns 0 if X was not on the list of initialization 6663** routines. 6664*/ 6665int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6666 6667/* 6668** CAPI3REF: Reset Automatic Extension Loading 6669** 6670** ^This interface disables all automatic extensions previously 6671** registered using [sqlite3_auto_extension()]. 6672*/ 6673void sqlite3_reset_auto_extension(void); 6674 6675/* 6676** The interface to the virtual-table mechanism is currently considered 6677** to be experimental. The interface might change in incompatible ways. 6678** If this is a problem for you, do not use the interface at this time. 6679** 6680** When the virtual-table mechanism stabilizes, we will declare the 6681** interface fixed, support it indefinitely, and remove this comment. 6682*/ 6683 6684/* 6685** Structures used by the virtual table interface 6686*/ 6687typedef struct sqlite3_vtab sqlite3_vtab; 6688typedef struct sqlite3_index_info sqlite3_index_info; 6689typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6690typedef struct sqlite3_module sqlite3_module; 6691 6692/* 6693** CAPI3REF: Virtual Table Object 6694** KEYWORDS: sqlite3_module {virtual table module} 6695** 6696** This structure, sometimes called a "virtual table module", 6697** defines the implementation of a [virtual table]. 6698** This structure consists mostly of methods for the module. 6699** 6700** ^A virtual table module is created by filling in a persistent 6701** instance of this structure and passing a pointer to that instance 6702** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6703** ^The registration remains valid until it is replaced by a different 6704** module or until the [database connection] closes. The content 6705** of this structure must not change while it is registered with 6706** any database connection. 6707*/ 6708struct sqlite3_module { 6709 int iVersion; 6710 int (*xCreate)(sqlite3*, void *pAux, 6711 int argc, const char *const*argv, 6712 sqlite3_vtab **ppVTab, char**); 6713 int (*xConnect)(sqlite3*, void *pAux, 6714 int argc, const char *const*argv, 6715 sqlite3_vtab **ppVTab, char**); 6716 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6717 int (*xDisconnect)(sqlite3_vtab *pVTab); 6718 int (*xDestroy)(sqlite3_vtab *pVTab); 6719 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6720 int (*xClose)(sqlite3_vtab_cursor*); 6721 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6722 int argc, sqlite3_value **argv); 6723 int (*xNext)(sqlite3_vtab_cursor*); 6724 int (*xEof)(sqlite3_vtab_cursor*); 6725 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6726 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6727 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6728 int (*xBegin)(sqlite3_vtab *pVTab); 6729 int (*xSync)(sqlite3_vtab *pVTab); 6730 int (*xCommit)(sqlite3_vtab *pVTab); 6731 int (*xRollback)(sqlite3_vtab *pVTab); 6732 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6733 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6734 void **ppArg); 6735 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6736 /* The methods above are in version 1 of the sqlite_module object. Those 6737 ** below are for version 2 and greater. */ 6738 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6739 int (*xRelease)(sqlite3_vtab *pVTab, int); 6740 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6741 /* The methods above are in versions 1 and 2 of the sqlite_module object. 6742 ** Those below are for version 3 and greater. */ 6743 int (*xShadowName)(const char*); 6744}; 6745 6746/* 6747** CAPI3REF: Virtual Table Indexing Information 6748** KEYWORDS: sqlite3_index_info 6749** 6750** The sqlite3_index_info structure and its substructures is used as part 6751** of the [virtual table] interface to 6752** pass information into and receive the reply from the [xBestIndex] 6753** method of a [virtual table module]. The fields under **Inputs** are the 6754** inputs to xBestIndex and are read-only. xBestIndex inserts its 6755** results into the **Outputs** fields. 6756** 6757** ^(The aConstraint[] array records WHERE clause constraints of the form: 6758** 6759** <blockquote>column OP expr</blockquote> 6760** 6761** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6762** stored in aConstraint[].op using one of the 6763** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6764** ^(The index of the column is stored in 6765** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6766** expr on the right-hand side can be evaluated (and thus the constraint 6767** is usable) and false if it cannot.)^ 6768** 6769** ^The optimizer automatically inverts terms of the form "expr OP column" 6770** and makes other simplifications to the WHERE clause in an attempt to 6771** get as many WHERE clause terms into the form shown above as possible. 6772** ^The aConstraint[] array only reports WHERE clause terms that are 6773** relevant to the particular virtual table being queried. 6774** 6775** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6776** ^Each term of aOrderBy records a column of the ORDER BY clause. 6777** 6778** The colUsed field indicates which columns of the virtual table may be 6779** required by the current scan. Virtual table columns are numbered from 6780** zero in the order in which they appear within the CREATE TABLE statement 6781** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6782** the corresponding bit is set within the colUsed mask if the column may be 6783** required by SQLite. If the table has at least 64 columns and any column 6784** to the right of the first 63 is required, then bit 63 of colUsed is also 6785** set. In other words, column iCol may be required if the expression 6786** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6787** non-zero. 6788** 6789** The [xBestIndex] method must fill aConstraintUsage[] with information 6790** about what parameters to pass to xFilter. ^If argvIndex>0 then 6791** the right-hand side of the corresponding aConstraint[] is evaluated 6792** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6793** is true, then the constraint is assumed to be fully handled by the 6794** virtual table and might not be checked again by the byte code.)^ ^(The 6795** aConstraintUsage[].omit flag is an optimization hint. When the omit flag 6796** is left in its default setting of false, the constraint will always be 6797** checked separately in byte code. If the omit flag is change to true, then 6798** the constraint may or may not be checked in byte code. In other words, 6799** when the omit flag is true there is no guarantee that the constraint will 6800** not be checked again using byte code.)^ 6801** 6802** ^The idxNum and idxPtr values are recorded and passed into the 6803** [xFilter] method. 6804** ^[sqlite3_free()] is used to free idxPtr if and only if 6805** needToFreeIdxPtr is true. 6806** 6807** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6808** the correct order to satisfy the ORDER BY clause so that no separate 6809** sorting step is required. 6810** 6811** ^The estimatedCost value is an estimate of the cost of a particular 6812** strategy. A cost of N indicates that the cost of the strategy is similar 6813** to a linear scan of an SQLite table with N rows. A cost of log(N) 6814** indicates that the expense of the operation is similar to that of a 6815** binary search on a unique indexed field of an SQLite table with N rows. 6816** 6817** ^The estimatedRows value is an estimate of the number of rows that 6818** will be returned by the strategy. 6819** 6820** The xBestIndex method may optionally populate the idxFlags field with a 6821** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6822** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6823** assumes that the strategy may visit at most one row. 6824** 6825** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6826** SQLite also assumes that if a call to the xUpdate() method is made as 6827** part of the same statement to delete or update a virtual table row and the 6828** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6829** any database changes. In other words, if the xUpdate() returns 6830** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6831** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6832** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6833** the xUpdate method are automatically rolled back by SQLite. 6834** 6835** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6836** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6837** If a virtual table extension is 6838** used with an SQLite version earlier than 3.8.2, the results of attempting 6839** to read or write the estimatedRows field are undefined (but are likely 6840** to include crashing the application). The estimatedRows field should 6841** therefore only be used if [sqlite3_libversion_number()] returns a 6842** value greater than or equal to 3008002. Similarly, the idxFlags field 6843** was added for [version 3.9.0] ([dateof:3.9.0]). 6844** It may therefore only be used if 6845** sqlite3_libversion_number() returns a value greater than or equal to 6846** 3009000. 6847*/ 6848struct sqlite3_index_info { 6849 /* Inputs */ 6850 int nConstraint; /* Number of entries in aConstraint */ 6851 struct sqlite3_index_constraint { 6852 int iColumn; /* Column constrained. -1 for ROWID */ 6853 unsigned char op; /* Constraint operator */ 6854 unsigned char usable; /* True if this constraint is usable */ 6855 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6856 } *aConstraint; /* Table of WHERE clause constraints */ 6857 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6858 struct sqlite3_index_orderby { 6859 int iColumn; /* Column number */ 6860 unsigned char desc; /* True for DESC. False for ASC. */ 6861 } *aOrderBy; /* The ORDER BY clause */ 6862 /* Outputs */ 6863 struct sqlite3_index_constraint_usage { 6864 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6865 unsigned char omit; /* Do not code a test for this constraint */ 6866 } *aConstraintUsage; 6867 int idxNum; /* Number used to identify the index */ 6868 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6869 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6870 int orderByConsumed; /* True if output is already ordered */ 6871 double estimatedCost; /* Estimated cost of using this index */ 6872 /* Fields below are only available in SQLite 3.8.2 and later */ 6873 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6874 /* Fields below are only available in SQLite 3.9.0 and later */ 6875 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6876 /* Fields below are only available in SQLite 3.10.0 and later */ 6877 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6878}; 6879 6880/* 6881** CAPI3REF: Virtual Table Scan Flags 6882** 6883** Virtual table implementations are allowed to set the 6884** [sqlite3_index_info].idxFlags field to some combination of 6885** these bits. 6886*/ 6887#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6888 6889/* 6890** CAPI3REF: Virtual Table Constraint Operator Codes 6891** 6892** These macros define the allowed values for the 6893** [sqlite3_index_info].aConstraint[].op field. Each value represents 6894** an operator that is part of a constraint term in the wHERE clause of 6895** a query that uses a [virtual table]. 6896*/ 6897#define SQLITE_INDEX_CONSTRAINT_EQ 2 6898#define SQLITE_INDEX_CONSTRAINT_GT 4 6899#define SQLITE_INDEX_CONSTRAINT_LE 8 6900#define SQLITE_INDEX_CONSTRAINT_LT 16 6901#define SQLITE_INDEX_CONSTRAINT_GE 32 6902#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6903#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6904#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6905#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6906#define SQLITE_INDEX_CONSTRAINT_NE 68 6907#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6908#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6909#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6910#define SQLITE_INDEX_CONSTRAINT_IS 72 6911#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150 6912 6913/* 6914** CAPI3REF: Register A Virtual Table Implementation 6915** METHOD: sqlite3 6916** 6917** ^These routines are used to register a new [virtual table module] name. 6918** ^Module names must be registered before 6919** creating a new [virtual table] using the module and before using a 6920** preexisting [virtual table] for the module. 6921** 6922** ^The module name is registered on the [database connection] specified 6923** by the first parameter. ^The name of the module is given by the 6924** second parameter. ^The third parameter is a pointer to 6925** the implementation of the [virtual table module]. ^The fourth 6926** parameter is an arbitrary client data pointer that is passed through 6927** into the [xCreate] and [xConnect] methods of the virtual table module 6928** when a new virtual table is be being created or reinitialized. 6929** 6930** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6931** is a pointer to a destructor for the pClientData. ^SQLite will 6932** invoke the destructor function (if it is not NULL) when SQLite 6933** no longer needs the pClientData pointer. ^The destructor will also 6934** be invoked if the call to sqlite3_create_module_v2() fails. 6935** ^The sqlite3_create_module() 6936** interface is equivalent to sqlite3_create_module_v2() with a NULL 6937** destructor. 6938** 6939** ^If the third parameter (the pointer to the sqlite3_module object) is 6940** NULL then no new module is create and any existing modules with the 6941** same name are dropped. 6942** 6943** See also: [sqlite3_drop_modules()] 6944*/ 6945int sqlite3_create_module( 6946 sqlite3 *db, /* SQLite connection to register module with */ 6947 const char *zName, /* Name of the module */ 6948 const sqlite3_module *p, /* Methods for the module */ 6949 void *pClientData /* Client data for xCreate/xConnect */ 6950); 6951int sqlite3_create_module_v2( 6952 sqlite3 *db, /* SQLite connection to register module with */ 6953 const char *zName, /* Name of the module */ 6954 const sqlite3_module *p, /* Methods for the module */ 6955 void *pClientData, /* Client data for xCreate/xConnect */ 6956 void(*xDestroy)(void*) /* Module destructor function */ 6957); 6958 6959/* 6960** CAPI3REF: Remove Unnecessary Virtual Table Implementations 6961** METHOD: sqlite3 6962** 6963** ^The sqlite3_drop_modules(D,L) interface removes all virtual 6964** table modules from database connection D except those named on list L. 6965** The L parameter must be either NULL or a pointer to an array of pointers 6966** to strings where the array is terminated by a single NULL pointer. 6967** ^If the L parameter is NULL, then all virtual table modules are removed. 6968** 6969** See also: [sqlite3_create_module()] 6970*/ 6971int sqlite3_drop_modules( 6972 sqlite3 *db, /* Remove modules from this connection */ 6973 const char **azKeep /* Except, do not remove the ones named here */ 6974); 6975 6976/* 6977** CAPI3REF: Virtual Table Instance Object 6978** KEYWORDS: sqlite3_vtab 6979** 6980** Every [virtual table module] implementation uses a subclass 6981** of this object to describe a particular instance 6982** of the [virtual table]. Each subclass will 6983** be tailored to the specific needs of the module implementation. 6984** The purpose of this superclass is to define certain fields that are 6985** common to all module implementations. 6986** 6987** ^Virtual tables methods can set an error message by assigning a 6988** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6989** take care that any prior string is freed by a call to [sqlite3_free()] 6990** prior to assigning a new string to zErrMsg. ^After the error message 6991** is delivered up to the client application, the string will be automatically 6992** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6993*/ 6994struct sqlite3_vtab { 6995 const sqlite3_module *pModule; /* The module for this virtual table */ 6996 int nRef; /* Number of open cursors */ 6997 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6998 /* Virtual table implementations will typically add additional fields */ 6999}; 7000 7001/* 7002** CAPI3REF: Virtual Table Cursor Object 7003** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 7004** 7005** Every [virtual table module] implementation uses a subclass of the 7006** following structure to describe cursors that point into the 7007** [virtual table] and are used 7008** to loop through the virtual table. Cursors are created using the 7009** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 7010** by the [sqlite3_module.xClose | xClose] method. Cursors are used 7011** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 7012** of the module. Each module implementation will define 7013** the content of a cursor structure to suit its own needs. 7014** 7015** This superclass exists in order to define fields of the cursor that 7016** are common to all implementations. 7017*/ 7018struct sqlite3_vtab_cursor { 7019 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 7020 /* Virtual table implementations will typically add additional fields */ 7021}; 7022 7023/* 7024** CAPI3REF: Declare The Schema Of A Virtual Table 7025** 7026** ^The [xCreate] and [xConnect] methods of a 7027** [virtual table module] call this interface 7028** to declare the format (the names and datatypes of the columns) of 7029** the virtual tables they implement. 7030*/ 7031int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 7032 7033/* 7034** CAPI3REF: Overload A Function For A Virtual Table 7035** METHOD: sqlite3 7036** 7037** ^(Virtual tables can provide alternative implementations of functions 7038** using the [xFindFunction] method of the [virtual table module]. 7039** But global versions of those functions 7040** must exist in order to be overloaded.)^ 7041** 7042** ^(This API makes sure a global version of a function with a particular 7043** name and number of parameters exists. If no such function exists 7044** before this API is called, a new function is created.)^ ^The implementation 7045** of the new function always causes an exception to be thrown. So 7046** the new function is not good for anything by itself. Its only 7047** purpose is to be a placeholder function that can be overloaded 7048** by a [virtual table]. 7049*/ 7050int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 7051 7052/* 7053** The interface to the virtual-table mechanism defined above (back up 7054** to a comment remarkably similar to this one) is currently considered 7055** to be experimental. The interface might change in incompatible ways. 7056** If this is a problem for you, do not use the interface at this time. 7057** 7058** When the virtual-table mechanism stabilizes, we will declare the 7059** interface fixed, support it indefinitely, and remove this comment. 7060*/ 7061 7062/* 7063** CAPI3REF: A Handle To An Open BLOB 7064** KEYWORDS: {BLOB handle} {BLOB handles} 7065** 7066** An instance of this object represents an open BLOB on which 7067** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 7068** ^Objects of this type are created by [sqlite3_blob_open()] 7069** and destroyed by [sqlite3_blob_close()]. 7070** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 7071** can be used to read or write small subsections of the BLOB. 7072** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 7073*/ 7074typedef struct sqlite3_blob sqlite3_blob; 7075 7076/* 7077** CAPI3REF: Open A BLOB For Incremental I/O 7078** METHOD: sqlite3 7079** CONSTRUCTOR: sqlite3_blob 7080** 7081** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 7082** in row iRow, column zColumn, table zTable in database zDb; 7083** in other words, the same BLOB that would be selected by: 7084** 7085** <pre> 7086** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 7087** </pre>)^ 7088** 7089** ^(Parameter zDb is not the filename that contains the database, but 7090** rather the symbolic name of the database. For attached databases, this is 7091** the name that appears after the AS keyword in the [ATTACH] statement. 7092** For the main database file, the database name is "main". For TEMP 7093** tables, the database name is "temp".)^ 7094** 7095** ^If the flags parameter is non-zero, then the BLOB is opened for read 7096** and write access. ^If the flags parameter is zero, the BLOB is opened for 7097** read-only access. 7098** 7099** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 7100** in *ppBlob. Otherwise an [error code] is returned and, unless the error 7101** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 7102** the API is not misused, it is always safe to call [sqlite3_blob_close()] 7103** on *ppBlob after this function it returns. 7104** 7105** This function fails with SQLITE_ERROR if any of the following are true: 7106** <ul> 7107** <li> ^(Database zDb does not exist)^, 7108** <li> ^(Table zTable does not exist within database zDb)^, 7109** <li> ^(Table zTable is a WITHOUT ROWID table)^, 7110** <li> ^(Column zColumn does not exist)^, 7111** <li> ^(Row iRow is not present in the table)^, 7112** <li> ^(The specified column of row iRow contains a value that is not 7113** a TEXT or BLOB value)^, 7114** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 7115** constraint and the blob is being opened for read/write access)^, 7116** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 7117** column zColumn is part of a [child key] definition and the blob is 7118** being opened for read/write access)^. 7119** </ul> 7120** 7121** ^Unless it returns SQLITE_MISUSE, this function sets the 7122** [database connection] error code and message accessible via 7123** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7124** 7125** A BLOB referenced by sqlite3_blob_open() may be read using the 7126** [sqlite3_blob_read()] interface and modified by using 7127** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 7128** different row of the same table using the [sqlite3_blob_reopen()] 7129** interface. However, the column, table, or database of a [BLOB handle] 7130** cannot be changed after the [BLOB handle] is opened. 7131** 7132** ^(If the row that a BLOB handle points to is modified by an 7133** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 7134** then the BLOB handle is marked as "expired". 7135** This is true if any column of the row is changed, even a column 7136** other than the one the BLOB handle is open on.)^ 7137** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 7138** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 7139** ^(Changes written into a BLOB prior to the BLOB expiring are not 7140** rolled back by the expiration of the BLOB. Such changes will eventually 7141** commit if the transaction continues to completion.)^ 7142** 7143** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 7144** the opened blob. ^The size of a blob may not be changed by this 7145** interface. Use the [UPDATE] SQL command to change the size of a 7146** blob. 7147** 7148** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 7149** and the built-in [zeroblob] SQL function may be used to create a 7150** zero-filled blob to read or write using the incremental-blob interface. 7151** 7152** To avoid a resource leak, every open [BLOB handle] should eventually 7153** be released by a call to [sqlite3_blob_close()]. 7154** 7155** See also: [sqlite3_blob_close()], 7156** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 7157** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 7158*/ 7159int sqlite3_blob_open( 7160 sqlite3*, 7161 const char *zDb, 7162 const char *zTable, 7163 const char *zColumn, 7164 sqlite3_int64 iRow, 7165 int flags, 7166 sqlite3_blob **ppBlob 7167); 7168 7169/* 7170** CAPI3REF: Move a BLOB Handle to a New Row 7171** METHOD: sqlite3_blob 7172** 7173** ^This function is used to move an existing [BLOB handle] so that it points 7174** to a different row of the same database table. ^The new row is identified 7175** by the rowid value passed as the second argument. Only the row can be 7176** changed. ^The database, table and column on which the blob handle is open 7177** remain the same. Moving an existing [BLOB handle] to a new row is 7178** faster than closing the existing handle and opening a new one. 7179** 7180** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 7181** it must exist and there must be either a blob or text value stored in 7182** the nominated column.)^ ^If the new row is not present in the table, or if 7183** it does not contain a blob or text value, or if another error occurs, an 7184** SQLite error code is returned and the blob handle is considered aborted. 7185** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 7186** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 7187** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 7188** always returns zero. 7189** 7190** ^This function sets the database handle error code and message. 7191*/ 7192int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 7193 7194/* 7195** CAPI3REF: Close A BLOB Handle 7196** DESTRUCTOR: sqlite3_blob 7197** 7198** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 7199** unconditionally. Even if this routine returns an error code, the 7200** handle is still closed.)^ 7201** 7202** ^If the blob handle being closed was opened for read-write access, and if 7203** the database is in auto-commit mode and there are no other open read-write 7204** blob handles or active write statements, the current transaction is 7205** committed. ^If an error occurs while committing the transaction, an error 7206** code is returned and the transaction rolled back. 7207** 7208** Calling this function with an argument that is not a NULL pointer or an 7209** open blob handle results in undefined behaviour. ^Calling this routine 7210** with a null pointer (such as would be returned by a failed call to 7211** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 7212** is passed a valid open blob handle, the values returned by the 7213** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 7214*/ 7215int sqlite3_blob_close(sqlite3_blob *); 7216 7217/* 7218** CAPI3REF: Return The Size Of An Open BLOB 7219** METHOD: sqlite3_blob 7220** 7221** ^Returns the size in bytes of the BLOB accessible via the 7222** successfully opened [BLOB handle] in its only argument. ^The 7223** incremental blob I/O routines can only read or overwriting existing 7224** blob content; they cannot change the size of a blob. 7225** 7226** This routine only works on a [BLOB handle] which has been created 7227** by a prior successful call to [sqlite3_blob_open()] and which has not 7228** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7229** to this routine results in undefined and probably undesirable behavior. 7230*/ 7231int sqlite3_blob_bytes(sqlite3_blob *); 7232 7233/* 7234** CAPI3REF: Read Data From A BLOB Incrementally 7235** METHOD: sqlite3_blob 7236** 7237** ^(This function is used to read data from an open [BLOB handle] into a 7238** caller-supplied buffer. N bytes of data are copied into buffer Z 7239** from the open BLOB, starting at offset iOffset.)^ 7240** 7241** ^If offset iOffset is less than N bytes from the end of the BLOB, 7242** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 7243** less than zero, [SQLITE_ERROR] is returned and no data is read. 7244** ^The size of the blob (and hence the maximum value of N+iOffset) 7245** can be determined using the [sqlite3_blob_bytes()] interface. 7246** 7247** ^An attempt to read from an expired [BLOB handle] fails with an 7248** error code of [SQLITE_ABORT]. 7249** 7250** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 7251** Otherwise, an [error code] or an [extended error code] is returned.)^ 7252** 7253** This routine only works on a [BLOB handle] which has been created 7254** by a prior successful call to [sqlite3_blob_open()] and which has not 7255** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7256** to this routine results in undefined and probably undesirable behavior. 7257** 7258** See also: [sqlite3_blob_write()]. 7259*/ 7260int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 7261 7262/* 7263** CAPI3REF: Write Data Into A BLOB Incrementally 7264** METHOD: sqlite3_blob 7265** 7266** ^(This function is used to write data into an open [BLOB handle] from a 7267** caller-supplied buffer. N bytes of data are copied from the buffer Z 7268** into the open BLOB, starting at offset iOffset.)^ 7269** 7270** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 7271** Otherwise, an [error code] or an [extended error code] is returned.)^ 7272** ^Unless SQLITE_MISUSE is returned, this function sets the 7273** [database connection] error code and message accessible via 7274** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 7275** 7276** ^If the [BLOB handle] passed as the first argument was not opened for 7277** writing (the flags parameter to [sqlite3_blob_open()] was zero), 7278** this function returns [SQLITE_READONLY]. 7279** 7280** This function may only modify the contents of the BLOB; it is 7281** not possible to increase the size of a BLOB using this API. 7282** ^If offset iOffset is less than N bytes from the end of the BLOB, 7283** [SQLITE_ERROR] is returned and no data is written. The size of the 7284** BLOB (and hence the maximum value of N+iOffset) can be determined 7285** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 7286** than zero [SQLITE_ERROR] is returned and no data is written. 7287** 7288** ^An attempt to write to an expired [BLOB handle] fails with an 7289** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 7290** before the [BLOB handle] expired are not rolled back by the 7291** expiration of the handle, though of course those changes might 7292** have been overwritten by the statement that expired the BLOB handle 7293** or by other independent statements. 7294** 7295** This routine only works on a [BLOB handle] which has been created 7296** by a prior successful call to [sqlite3_blob_open()] and which has not 7297** been closed by [sqlite3_blob_close()]. Passing any other pointer in 7298** to this routine results in undefined and probably undesirable behavior. 7299** 7300** See also: [sqlite3_blob_read()]. 7301*/ 7302int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 7303 7304/* 7305** CAPI3REF: Virtual File System Objects 7306** 7307** A virtual filesystem (VFS) is an [sqlite3_vfs] object 7308** that SQLite uses to interact 7309** with the underlying operating system. Most SQLite builds come with a 7310** single default VFS that is appropriate for the host computer. 7311** New VFSes can be registered and existing VFSes can be unregistered. 7312** The following interfaces are provided. 7313** 7314** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 7315** ^Names are case sensitive. 7316** ^Names are zero-terminated UTF-8 strings. 7317** ^If there is no match, a NULL pointer is returned. 7318** ^If zVfsName is NULL then the default VFS is returned. 7319** 7320** ^New VFSes are registered with sqlite3_vfs_register(). 7321** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 7322** ^The same VFS can be registered multiple times without injury. 7323** ^To make an existing VFS into the default VFS, register it again 7324** with the makeDflt flag set. If two different VFSes with the 7325** same name are registered, the behavior is undefined. If a 7326** VFS is registered with a name that is NULL or an empty string, 7327** then the behavior is undefined. 7328** 7329** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 7330** ^(If the default VFS is unregistered, another VFS is chosen as 7331** the default. The choice for the new VFS is arbitrary.)^ 7332*/ 7333sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 7334int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 7335int sqlite3_vfs_unregister(sqlite3_vfs*); 7336 7337/* 7338** CAPI3REF: Mutexes 7339** 7340** The SQLite core uses these routines for thread 7341** synchronization. Though they are intended for internal 7342** use by SQLite, code that links against SQLite is 7343** permitted to use any of these routines. 7344** 7345** The SQLite source code contains multiple implementations 7346** of these mutex routines. An appropriate implementation 7347** is selected automatically at compile-time. The following 7348** implementations are available in the SQLite core: 7349** 7350** <ul> 7351** <li> SQLITE_MUTEX_PTHREADS 7352** <li> SQLITE_MUTEX_W32 7353** <li> SQLITE_MUTEX_NOOP 7354** </ul> 7355** 7356** The SQLITE_MUTEX_NOOP implementation is a set of routines 7357** that does no real locking and is appropriate for use in 7358** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 7359** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 7360** and Windows. 7361** 7362** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 7363** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 7364** implementation is included with the library. In this case the 7365** application must supply a custom mutex implementation using the 7366** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 7367** before calling sqlite3_initialize() or any other public sqlite3_ 7368** function that calls sqlite3_initialize(). 7369** 7370** ^The sqlite3_mutex_alloc() routine allocates a new 7371** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 7372** routine returns NULL if it is unable to allocate the requested 7373** mutex. The argument to sqlite3_mutex_alloc() must one of these 7374** integer constants: 7375** 7376** <ul> 7377** <li> SQLITE_MUTEX_FAST 7378** <li> SQLITE_MUTEX_RECURSIVE 7379** <li> SQLITE_MUTEX_STATIC_MASTER 7380** <li> SQLITE_MUTEX_STATIC_MEM 7381** <li> SQLITE_MUTEX_STATIC_OPEN 7382** <li> SQLITE_MUTEX_STATIC_PRNG 7383** <li> SQLITE_MUTEX_STATIC_LRU 7384** <li> SQLITE_MUTEX_STATIC_PMEM 7385** <li> SQLITE_MUTEX_STATIC_APP1 7386** <li> SQLITE_MUTEX_STATIC_APP2 7387** <li> SQLITE_MUTEX_STATIC_APP3 7388** <li> SQLITE_MUTEX_STATIC_VFS1 7389** <li> SQLITE_MUTEX_STATIC_VFS2 7390** <li> SQLITE_MUTEX_STATIC_VFS3 7391** </ul> 7392** 7393** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 7394** cause sqlite3_mutex_alloc() to create 7395** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 7396** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 7397** The mutex implementation does not need to make a distinction 7398** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 7399** not want to. SQLite will only request a recursive mutex in 7400** cases where it really needs one. If a faster non-recursive mutex 7401** implementation is available on the host platform, the mutex subsystem 7402** might return such a mutex in response to SQLITE_MUTEX_FAST. 7403** 7404** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 7405** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 7406** a pointer to a static preexisting mutex. ^Nine static mutexes are 7407** used by the current version of SQLite. Future versions of SQLite 7408** may add additional static mutexes. Static mutexes are for internal 7409** use by SQLite only. Applications that use SQLite mutexes should 7410** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 7411** SQLITE_MUTEX_RECURSIVE. 7412** 7413** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 7414** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 7415** returns a different mutex on every call. ^For the static 7416** mutex types, the same mutex is returned on every call that has 7417** the same type number. 7418** 7419** ^The sqlite3_mutex_free() routine deallocates a previously 7420** allocated dynamic mutex. Attempting to deallocate a static 7421** mutex results in undefined behavior. 7422** 7423** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 7424** to enter a mutex. ^If another thread is already within the mutex, 7425** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 7426** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 7427** upon successful entry. ^(Mutexes created using 7428** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 7429** In such cases, the 7430** mutex must be exited an equal number of times before another thread 7431** can enter.)^ If the same thread tries to enter any mutex other 7432** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 7433** 7434** ^(Some systems (for example, Windows 95) do not support the operation 7435** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 7436** will always return SQLITE_BUSY. The SQLite core only ever uses 7437** sqlite3_mutex_try() as an optimization so this is acceptable 7438** behavior.)^ 7439** 7440** ^The sqlite3_mutex_leave() routine exits a mutex that was 7441** previously entered by the same thread. The behavior 7442** is undefined if the mutex is not currently entered by the 7443** calling thread or is not currently allocated. 7444** 7445** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 7446** sqlite3_mutex_leave() is a NULL pointer, then all three routines 7447** behave as no-ops. 7448** 7449** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 7450*/ 7451sqlite3_mutex *sqlite3_mutex_alloc(int); 7452void sqlite3_mutex_free(sqlite3_mutex*); 7453void sqlite3_mutex_enter(sqlite3_mutex*); 7454int sqlite3_mutex_try(sqlite3_mutex*); 7455void sqlite3_mutex_leave(sqlite3_mutex*); 7456 7457/* 7458** CAPI3REF: Mutex Methods Object 7459** 7460** An instance of this structure defines the low-level routines 7461** used to allocate and use mutexes. 7462** 7463** Usually, the default mutex implementations provided by SQLite are 7464** sufficient, however the application has the option of substituting a custom 7465** implementation for specialized deployments or systems for which SQLite 7466** does not provide a suitable implementation. In this case, the application 7467** creates and populates an instance of this structure to pass 7468** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 7469** Additionally, an instance of this structure can be used as an 7470** output variable when querying the system for the current mutex 7471** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 7472** 7473** ^The xMutexInit method defined by this structure is invoked as 7474** part of system initialization by the sqlite3_initialize() function. 7475** ^The xMutexInit routine is called by SQLite exactly once for each 7476** effective call to [sqlite3_initialize()]. 7477** 7478** ^The xMutexEnd method defined by this structure is invoked as 7479** part of system shutdown by the sqlite3_shutdown() function. The 7480** implementation of this method is expected to release all outstanding 7481** resources obtained by the mutex methods implementation, especially 7482** those obtained by the xMutexInit method. ^The xMutexEnd() 7483** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 7484** 7485** ^(The remaining seven methods defined by this structure (xMutexAlloc, 7486** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 7487** xMutexNotheld) implement the following interfaces (respectively): 7488** 7489** <ul> 7490** <li> [sqlite3_mutex_alloc()] </li> 7491** <li> [sqlite3_mutex_free()] </li> 7492** <li> [sqlite3_mutex_enter()] </li> 7493** <li> [sqlite3_mutex_try()] </li> 7494** <li> [sqlite3_mutex_leave()] </li> 7495** <li> [sqlite3_mutex_held()] </li> 7496** <li> [sqlite3_mutex_notheld()] </li> 7497** </ul>)^ 7498** 7499** The only difference is that the public sqlite3_XXX functions enumerated 7500** above silently ignore any invocations that pass a NULL pointer instead 7501** of a valid mutex handle. The implementations of the methods defined 7502** by this structure are not required to handle this case. The results 7503** of passing a NULL pointer instead of a valid mutex handle are undefined 7504** (i.e. it is acceptable to provide an implementation that segfaults if 7505** it is passed a NULL pointer). 7506** 7507** The xMutexInit() method must be threadsafe. It must be harmless to 7508** invoke xMutexInit() multiple times within the same process and without 7509** intervening calls to xMutexEnd(). Second and subsequent calls to 7510** xMutexInit() must be no-ops. 7511** 7512** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 7513** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 7514** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 7515** memory allocation for a fast or recursive mutex. 7516** 7517** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 7518** called, but only if the prior call to xMutexInit returned SQLITE_OK. 7519** If xMutexInit fails in any way, it is expected to clean up after itself 7520** prior to returning. 7521*/ 7522typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 7523struct sqlite3_mutex_methods { 7524 int (*xMutexInit)(void); 7525 int (*xMutexEnd)(void); 7526 sqlite3_mutex *(*xMutexAlloc)(int); 7527 void (*xMutexFree)(sqlite3_mutex *); 7528 void (*xMutexEnter)(sqlite3_mutex *); 7529 int (*xMutexTry)(sqlite3_mutex *); 7530 void (*xMutexLeave)(sqlite3_mutex *); 7531 int (*xMutexHeld)(sqlite3_mutex *); 7532 int (*xMutexNotheld)(sqlite3_mutex *); 7533}; 7534 7535/* 7536** CAPI3REF: Mutex Verification Routines 7537** 7538** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 7539** are intended for use inside assert() statements. The SQLite core 7540** never uses these routines except inside an assert() and applications 7541** are advised to follow the lead of the core. The SQLite core only 7542** provides implementations for these routines when it is compiled 7543** with the SQLITE_DEBUG flag. External mutex implementations 7544** are only required to provide these routines if SQLITE_DEBUG is 7545** defined and if NDEBUG is not defined. 7546** 7547** These routines should return true if the mutex in their argument 7548** is held or not held, respectively, by the calling thread. 7549** 7550** The implementation is not required to provide versions of these 7551** routines that actually work. If the implementation does not provide working 7552** versions of these routines, it should at least provide stubs that always 7553** return true so that one does not get spurious assertion failures. 7554** 7555** If the argument to sqlite3_mutex_held() is a NULL pointer then 7556** the routine should return 1. This seems counter-intuitive since 7557** clearly the mutex cannot be held if it does not exist. But 7558** the reason the mutex does not exist is because the build is not 7559** using mutexes. And we do not want the assert() containing the 7560** call to sqlite3_mutex_held() to fail, so a non-zero return is 7561** the appropriate thing to do. The sqlite3_mutex_notheld() 7562** interface should also return 1 when given a NULL pointer. 7563*/ 7564#ifndef NDEBUG 7565int sqlite3_mutex_held(sqlite3_mutex*); 7566int sqlite3_mutex_notheld(sqlite3_mutex*); 7567#endif 7568 7569/* 7570** CAPI3REF: Mutex Types 7571** 7572** The [sqlite3_mutex_alloc()] interface takes a single argument 7573** which is one of these integer constants. 7574** 7575** The set of static mutexes may change from one SQLite release to the 7576** next. Applications that override the built-in mutex logic must be 7577** prepared to accommodate additional static mutexes. 7578*/ 7579#define SQLITE_MUTEX_FAST 0 7580#define SQLITE_MUTEX_RECURSIVE 1 7581#define SQLITE_MUTEX_STATIC_MASTER 2 7582#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 7583#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 7584#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 7585#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 7586#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 7587#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 7588#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 7589#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 7590#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 7591#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 7592#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 7593#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 7594#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 7595 7596/* 7597** CAPI3REF: Retrieve the mutex for a database connection 7598** METHOD: sqlite3 7599** 7600** ^This interface returns a pointer the [sqlite3_mutex] object that 7601** serializes access to the [database connection] given in the argument 7602** when the [threading mode] is Serialized. 7603** ^If the [threading mode] is Single-thread or Multi-thread then this 7604** routine returns a NULL pointer. 7605*/ 7606sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 7607 7608/* 7609** CAPI3REF: Low-Level Control Of Database Files 7610** METHOD: sqlite3 7611** KEYWORDS: {file control} 7612** 7613** ^The [sqlite3_file_control()] interface makes a direct call to the 7614** xFileControl method for the [sqlite3_io_methods] object associated 7615** with a particular database identified by the second argument. ^The 7616** name of the database is "main" for the main database or "temp" for the 7617** TEMP database, or the name that appears after the AS keyword for 7618** databases that are added using the [ATTACH] SQL command. 7619** ^A NULL pointer can be used in place of "main" to refer to the 7620** main database file. 7621** ^The third and fourth parameters to this routine 7622** are passed directly through to the second and third parameters of 7623** the xFileControl method. ^The return value of the xFileControl 7624** method becomes the return value of this routine. 7625** 7626** A few opcodes for [sqlite3_file_control()] are handled directly 7627** by the SQLite core and never invoke the 7628** sqlite3_io_methods.xFileControl method. 7629** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 7630** a pointer to the underlying [sqlite3_file] object to be written into 7631** the space pointed to by the 4th parameter. The 7632** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns 7633** the [sqlite3_file] object associated with the journal file instead of 7634** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns 7635** a pointer to the underlying [sqlite3_vfs] object for the file. 7636** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter 7637** from the pager. 7638** 7639** ^If the second parameter (zDbName) does not match the name of any 7640** open database file, then SQLITE_ERROR is returned. ^This error 7641** code is not remembered and will not be recalled by [sqlite3_errcode()] 7642** or [sqlite3_errmsg()]. The underlying xFileControl method might 7643** also return SQLITE_ERROR. There is no way to distinguish between 7644** an incorrect zDbName and an SQLITE_ERROR return from the underlying 7645** xFileControl method. 7646** 7647** See also: [file control opcodes] 7648*/ 7649int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 7650 7651/* 7652** CAPI3REF: Testing Interface 7653** 7654** ^The sqlite3_test_control() interface is used to read out internal 7655** state of SQLite and to inject faults into SQLite for testing 7656** purposes. ^The first parameter is an operation code that determines 7657** the number, meaning, and operation of all subsequent parameters. 7658** 7659** This interface is not for use by applications. It exists solely 7660** for verifying the correct operation of the SQLite library. Depending 7661** on how the SQLite library is compiled, this interface might not exist. 7662** 7663** The details of the operation codes, their meanings, the parameters 7664** they take, and what they do are all subject to change without notice. 7665** Unlike most of the SQLite API, this function is not guaranteed to 7666** operate consistently from one release to the next. 7667*/ 7668int sqlite3_test_control(int op, ...); 7669 7670/* 7671** CAPI3REF: Testing Interface Operation Codes 7672** 7673** These constants are the valid operation code parameters used 7674** as the first argument to [sqlite3_test_control()]. 7675** 7676** These parameters and their meanings are subject to change 7677** without notice. These values are for testing purposes only. 7678** Applications should not use any of these parameters or the 7679** [sqlite3_test_control()] interface. 7680*/ 7681#define SQLITE_TESTCTRL_FIRST 5 7682#define SQLITE_TESTCTRL_PRNG_SAVE 5 7683#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7684#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */ 7685#define SQLITE_TESTCTRL_BITVEC_TEST 8 7686#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7687#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7688#define SQLITE_TESTCTRL_PENDING_BYTE 11 7689#define SQLITE_TESTCTRL_ASSERT 12 7690#define SQLITE_TESTCTRL_ALWAYS 13 7691#define SQLITE_TESTCTRL_RESERVE 14 /* NOT USED */ 7692#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7693#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */ 7694#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7695#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17 7696#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7697#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7698#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7699#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7700#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7701#define SQLITE_TESTCTRL_BYTEORDER 22 7702#define SQLITE_TESTCTRL_ISINIT 23 7703#define SQLITE_TESTCTRL_SORTER_MMAP 24 7704#define SQLITE_TESTCTRL_IMPOSTER 25 7705#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7706#define SQLITE_TESTCTRL_RESULT_INTREAL 27 7707#define SQLITE_TESTCTRL_PRNG_SEED 28 7708#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29 7709#define SQLITE_TESTCTRL_LAST 29 /* Largest TESTCTRL */ 7710 7711/* 7712** CAPI3REF: SQL Keyword Checking 7713** 7714** These routines provide access to the set of SQL language keywords 7715** recognized by SQLite. Applications can uses these routines to determine 7716** whether or not a specific identifier needs to be escaped (for example, 7717** by enclosing in double-quotes) so as not to confuse the parser. 7718** 7719** The sqlite3_keyword_count() interface returns the number of distinct 7720** keywords understood by SQLite. 7721** 7722** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and 7723** makes *Z point to that keyword expressed as UTF8 and writes the number 7724** of bytes in the keyword into *L. The string that *Z points to is not 7725** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns 7726** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z 7727** or L are NULL or invalid pointers then calls to 7728** sqlite3_keyword_name(N,Z,L) result in undefined behavior. 7729** 7730** The sqlite3_keyword_check(Z,L) interface checks to see whether or not 7731** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero 7732** if it is and zero if not. 7733** 7734** The parser used by SQLite is forgiving. It is often possible to use 7735** a keyword as an identifier as long as such use does not result in a 7736** parsing ambiguity. For example, the statement 7737** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and 7738** creates a new table named "BEGIN" with three columns named 7739** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid 7740** using keywords as identifiers. Common techniques used to avoid keyword 7741** name collisions include: 7742** <ul> 7743** <li> Put all identifier names inside double-quotes. This is the official 7744** SQL way to escape identifier names. 7745** <li> Put identifier names inside [...]. This is not standard SQL, 7746** but it is what SQL Server does and so lots of programmers use this 7747** technique. 7748** <li> Begin every identifier with the letter "Z" as no SQL keywords start 7749** with "Z". 7750** <li> Include a digit somewhere in every identifier name. 7751** </ul> 7752** 7753** Note that the number of keywords understood by SQLite can depend on 7754** compile-time options. For example, "VACUUM" is not a keyword if 7755** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also, 7756** new keywords may be added to future releases of SQLite. 7757*/ 7758int sqlite3_keyword_count(void); 7759int sqlite3_keyword_name(int,const char**,int*); 7760int sqlite3_keyword_check(const char*,int); 7761 7762/* 7763** CAPI3REF: Dynamic String Object 7764** KEYWORDS: {dynamic string} 7765** 7766** An instance of the sqlite3_str object contains a dynamically-sized 7767** string under construction. 7768** 7769** The lifecycle of an sqlite3_str object is as follows: 7770** <ol> 7771** <li> ^The sqlite3_str object is created using [sqlite3_str_new()]. 7772** <li> ^Text is appended to the sqlite3_str object using various 7773** methods, such as [sqlite3_str_appendf()]. 7774** <li> ^The sqlite3_str object is destroyed and the string it created 7775** is returned using the [sqlite3_str_finish()] interface. 7776** </ol> 7777*/ 7778typedef struct sqlite3_str sqlite3_str; 7779 7780/* 7781** CAPI3REF: Create A New Dynamic String Object 7782** CONSTRUCTOR: sqlite3_str 7783** 7784** ^The [sqlite3_str_new(D)] interface allocates and initializes 7785** a new [sqlite3_str] object. To avoid memory leaks, the object returned by 7786** [sqlite3_str_new()] must be freed by a subsequent call to 7787** [sqlite3_str_finish(X)]. 7788** 7789** ^The [sqlite3_str_new(D)] interface always returns a pointer to a 7790** valid [sqlite3_str] object, though in the event of an out-of-memory 7791** error the returned object might be a special singleton that will 7792** silently reject new text, always return SQLITE_NOMEM from 7793** [sqlite3_str_errcode()], always return 0 for 7794** [sqlite3_str_length()], and always return NULL from 7795** [sqlite3_str_finish(X)]. It is always safe to use the value 7796** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter 7797** to any of the other [sqlite3_str] methods. 7798** 7799** The D parameter to [sqlite3_str_new(D)] may be NULL. If the 7800** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum 7801** length of the string contained in the [sqlite3_str] object will be 7802** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead 7803** of [SQLITE_MAX_LENGTH]. 7804*/ 7805sqlite3_str *sqlite3_str_new(sqlite3*); 7806 7807/* 7808** CAPI3REF: Finalize A Dynamic String 7809** DESTRUCTOR: sqlite3_str 7810** 7811** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X 7812** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()] 7813** that contains the constructed string. The calling application should 7814** pass the returned value to [sqlite3_free()] to avoid a memory leak. 7815** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any 7816** errors were encountered during construction of the string. ^The 7817** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the 7818** string in [sqlite3_str] object X is zero bytes long. 7819*/ 7820char *sqlite3_str_finish(sqlite3_str*); 7821 7822/* 7823** CAPI3REF: Add Content To A Dynamic String 7824** METHOD: sqlite3_str 7825** 7826** These interfaces add content to an sqlite3_str object previously obtained 7827** from [sqlite3_str_new()]. 7828** 7829** ^The [sqlite3_str_appendf(X,F,...)] and 7830** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf] 7831** functionality of SQLite to append formatted text onto the end of 7832** [sqlite3_str] object X. 7833** 7834** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S 7835** onto the end of the [sqlite3_str] object X. N must be non-negative. 7836** S must contain at least N non-zero bytes of content. To append a 7837** zero-terminated string in its entirety, use the [sqlite3_str_appendall()] 7838** method instead. 7839** 7840** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of 7841** zero-terminated string S onto the end of [sqlite3_str] object X. 7842** 7843** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the 7844** single-byte character C onto the end of [sqlite3_str] object X. 7845** ^This method can be used, for example, to add whitespace indentation. 7846** 7847** ^The [sqlite3_str_reset(X)] method resets the string under construction 7848** inside [sqlite3_str] object X back to zero bytes in length. 7849** 7850** These methods do not return a result code. ^If an error occurs, that fact 7851** is recorded in the [sqlite3_str] object and can be recovered by a 7852** subsequent call to [sqlite3_str_errcode(X)]. 7853*/ 7854void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...); 7855void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list); 7856void sqlite3_str_append(sqlite3_str*, const char *zIn, int N); 7857void sqlite3_str_appendall(sqlite3_str*, const char *zIn); 7858void sqlite3_str_appendchar(sqlite3_str*, int N, char C); 7859void sqlite3_str_reset(sqlite3_str*); 7860 7861/* 7862** CAPI3REF: Status Of A Dynamic String 7863** METHOD: sqlite3_str 7864** 7865** These interfaces return the current status of an [sqlite3_str] object. 7866** 7867** ^If any prior errors have occurred while constructing the dynamic string 7868** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return 7869** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns 7870** [SQLITE_NOMEM] following any out-of-memory error, or 7871** [SQLITE_TOOBIG] if the size of the dynamic string exceeds 7872** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors. 7873** 7874** ^The [sqlite3_str_length(X)] method returns the current length, in bytes, 7875** of the dynamic string under construction in [sqlite3_str] object X. 7876** ^The length returned by [sqlite3_str_length(X)] does not include the 7877** zero-termination byte. 7878** 7879** ^The [sqlite3_str_value(X)] method returns a pointer to the current 7880** content of the dynamic string under construction in X. The value 7881** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X 7882** and might be freed or altered by any subsequent method on the same 7883** [sqlite3_str] object. Applications must not used the pointer returned 7884** [sqlite3_str_value(X)] after any subsequent method call on the same 7885** object. ^Applications may change the content of the string returned 7886** by [sqlite3_str_value(X)] as long as they do not write into any bytes 7887** outside the range of 0 to [sqlite3_str_length(X)] and do not read or 7888** write any byte after any subsequent sqlite3_str method call. 7889*/ 7890int sqlite3_str_errcode(sqlite3_str*); 7891int sqlite3_str_length(sqlite3_str*); 7892char *sqlite3_str_value(sqlite3_str*); 7893 7894/* 7895** CAPI3REF: SQLite Runtime Status 7896** 7897** ^These interfaces are used to retrieve runtime status information 7898** about the performance of SQLite, and optionally to reset various 7899** highwater marks. ^The first argument is an integer code for 7900** the specific parameter to measure. ^(Recognized integer codes 7901** are of the form [status parameters | SQLITE_STATUS_...].)^ 7902** ^The current value of the parameter is returned into *pCurrent. 7903** ^The highest recorded value is returned in *pHighwater. ^If the 7904** resetFlag is true, then the highest record value is reset after 7905** *pHighwater is written. ^(Some parameters do not record the highest 7906** value. For those parameters 7907** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7908** ^(Other parameters record only the highwater mark and not the current 7909** value. For these latter parameters nothing is written into *pCurrent.)^ 7910** 7911** ^The sqlite3_status() and sqlite3_status64() routines return 7912** SQLITE_OK on success and a non-zero [error code] on failure. 7913** 7914** If either the current value or the highwater mark is too large to 7915** be represented by a 32-bit integer, then the values returned by 7916** sqlite3_status() are undefined. 7917** 7918** See also: [sqlite3_db_status()] 7919*/ 7920int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7921int sqlite3_status64( 7922 int op, 7923 sqlite3_int64 *pCurrent, 7924 sqlite3_int64 *pHighwater, 7925 int resetFlag 7926); 7927 7928 7929/* 7930** CAPI3REF: Status Parameters 7931** KEYWORDS: {status parameters} 7932** 7933** These integer constants designate various run-time status parameters 7934** that can be returned by [sqlite3_status()]. 7935** 7936** <dl> 7937** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7938** <dd>This parameter is the current amount of memory checked out 7939** using [sqlite3_malloc()], either directly or indirectly. The 7940** figure includes calls made to [sqlite3_malloc()] by the application 7941** and internal memory usage by the SQLite library. Auxiliary page-cache 7942** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7943** this parameter. The amount returned is the sum of the allocation 7944** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7945** 7946** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7947** <dd>This parameter records the largest memory allocation request 7948** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7949** internal equivalents). Only the value returned in the 7950** *pHighwater parameter to [sqlite3_status()] is of interest. 7951** The value written into the *pCurrent parameter is undefined.</dd>)^ 7952** 7953** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7954** <dd>This parameter records the number of separate memory allocations 7955** currently checked out.</dd>)^ 7956** 7957** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7958** <dd>This parameter returns the number of pages used out of the 7959** [pagecache memory allocator] that was configured using 7960** [SQLITE_CONFIG_PAGECACHE]. The 7961** value returned is in pages, not in bytes.</dd>)^ 7962** 7963** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7964** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7965** <dd>This parameter returns the number of bytes of page cache 7966** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7967** buffer and where forced to overflow to [sqlite3_malloc()]. The 7968** returned value includes allocations that overflowed because they 7969** where too large (they were larger than the "sz" parameter to 7970** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7971** no space was left in the page cache.</dd>)^ 7972** 7973** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7974** <dd>This parameter records the largest memory allocation request 7975** handed to the [pagecache memory allocator]. Only the value returned in the 7976** *pHighwater parameter to [sqlite3_status()] is of interest. 7977** The value written into the *pCurrent parameter is undefined.</dd>)^ 7978** 7979** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 7980** <dd>No longer used.</dd> 7981** 7982** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7983** <dd>No longer used.</dd> 7984** 7985** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7986** <dd>No longer used.</dd> 7987** 7988** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7989** <dd>The *pHighwater parameter records the deepest parser stack. 7990** The *pCurrent value is undefined. The *pHighwater value is only 7991** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7992** </dl> 7993** 7994** New status parameters may be added from time to time. 7995*/ 7996#define SQLITE_STATUS_MEMORY_USED 0 7997#define SQLITE_STATUS_PAGECACHE_USED 1 7998#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7999#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 8000#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 8001#define SQLITE_STATUS_MALLOC_SIZE 5 8002#define SQLITE_STATUS_PARSER_STACK 6 8003#define SQLITE_STATUS_PAGECACHE_SIZE 7 8004#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 8005#define SQLITE_STATUS_MALLOC_COUNT 9 8006 8007/* 8008** CAPI3REF: Database Connection Status 8009** METHOD: sqlite3 8010** 8011** ^This interface is used to retrieve runtime status information 8012** about a single [database connection]. ^The first argument is the 8013** database connection object to be interrogated. ^The second argument 8014** is an integer constant, taken from the set of 8015** [SQLITE_DBSTATUS options], that 8016** determines the parameter to interrogate. The set of 8017** [SQLITE_DBSTATUS options] is likely 8018** to grow in future releases of SQLite. 8019** 8020** ^The current value of the requested parameter is written into *pCur 8021** and the highest instantaneous value is written into *pHiwtr. ^If 8022** the resetFlg is true, then the highest instantaneous value is 8023** reset back down to the current value. 8024** 8025** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 8026** non-zero [error code] on failure. 8027** 8028** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 8029*/ 8030int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 8031 8032/* 8033** CAPI3REF: Status Parameters for database connections 8034** KEYWORDS: {SQLITE_DBSTATUS options} 8035** 8036** These constants are the available integer "verbs" that can be passed as 8037** the second argument to the [sqlite3_db_status()] interface. 8038** 8039** New verbs may be added in future releases of SQLite. Existing verbs 8040** might be discontinued. Applications should check the return code from 8041** [sqlite3_db_status()] to make sure that the call worked. 8042** The [sqlite3_db_status()] interface will return a non-zero error code 8043** if a discontinued or unsupported verb is invoked. 8044** 8045** <dl> 8046** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 8047** <dd>This parameter returns the number of lookaside memory slots currently 8048** checked out.</dd>)^ 8049** 8050** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 8051** <dd>This parameter returns the number of malloc attempts that were 8052** satisfied using lookaside memory. Only the high-water value is meaningful; 8053** the current value is always zero.)^ 8054** 8055** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 8056** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 8057** <dd>This parameter returns the number malloc attempts that might have 8058** been satisfied using lookaside memory but failed due to the amount of 8059** memory requested being larger than the lookaside slot size. 8060** Only the high-water value is meaningful; 8061** the current value is always zero.)^ 8062** 8063** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 8064** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 8065** <dd>This parameter returns the number malloc attempts that might have 8066** been satisfied using lookaside memory but failed due to all lookaside 8067** memory already being in use. 8068** Only the high-water value is meaningful; 8069** the current value is always zero.)^ 8070** 8071** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 8072** <dd>This parameter returns the approximate number of bytes of heap 8073** memory used by all pager caches associated with the database connection.)^ 8074** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 8075** 8076** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 8077** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 8078** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 8079** pager cache is shared between two or more connections the bytes of heap 8080** memory used by that pager cache is divided evenly between the attached 8081** connections.)^ In other words, if none of the pager caches associated 8082** with the database connection are shared, this request returns the same 8083** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 8084** shared, the value returned by this call will be smaller than that returned 8085** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 8086** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 8087** 8088** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 8089** <dd>This parameter returns the approximate number of bytes of heap 8090** memory used to store the schema for all databases associated 8091** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 8092** ^The full amount of memory used by the schemas is reported, even if the 8093** schema memory is shared with other database connections due to 8094** [shared cache mode] being enabled. 8095** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 8096** 8097** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 8098** <dd>This parameter returns the approximate number of bytes of heap 8099** and lookaside memory used by all prepared statements associated with 8100** the database connection.)^ 8101** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 8102** </dd> 8103** 8104** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 8105** <dd>This parameter returns the number of pager cache hits that have 8106** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 8107** is always 0. 8108** </dd> 8109** 8110** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 8111** <dd>This parameter returns the number of pager cache misses that have 8112** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 8113** is always 0. 8114** </dd> 8115** 8116** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 8117** <dd>This parameter returns the number of dirty cache entries that have 8118** been written to disk. Specifically, the number of pages written to the 8119** wal file in wal mode databases, or the number of pages written to the 8120** database file in rollback mode databases. Any pages written as part of 8121** transaction rollback or database recovery operations are not included. 8122** If an IO or other error occurs while writing a page to disk, the effect 8123** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 8124** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 8125** </dd> 8126** 8127** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 8128** <dd>This parameter returns the number of dirty cache entries that have 8129** been written to disk in the middle of a transaction due to the page 8130** cache overflowing. Transactions are more efficient if they are written 8131** to disk all at once. When pages spill mid-transaction, that introduces 8132** additional overhead. This parameter can be used help identify 8133** inefficiencies that can be resolved by increasing the cache size. 8134** </dd> 8135** 8136** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 8137** <dd>This parameter returns zero for the current value if and only if 8138** all foreign key constraints (deferred or immediate) have been 8139** resolved.)^ ^The highwater mark is always 0. 8140** </dd> 8141** </dl> 8142*/ 8143#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 8144#define SQLITE_DBSTATUS_CACHE_USED 1 8145#define SQLITE_DBSTATUS_SCHEMA_USED 2 8146#define SQLITE_DBSTATUS_STMT_USED 3 8147#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 8148#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 8149#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 8150#define SQLITE_DBSTATUS_CACHE_HIT 7 8151#define SQLITE_DBSTATUS_CACHE_MISS 8 8152#define SQLITE_DBSTATUS_CACHE_WRITE 9 8153#define SQLITE_DBSTATUS_DEFERRED_FKS 10 8154#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 8155#define SQLITE_DBSTATUS_CACHE_SPILL 12 8156#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 8157 8158 8159/* 8160** CAPI3REF: Prepared Statement Status 8161** METHOD: sqlite3_stmt 8162** 8163** ^(Each prepared statement maintains various 8164** [SQLITE_STMTSTATUS counters] that measure the number 8165** of times it has performed specific operations.)^ These counters can 8166** be used to monitor the performance characteristics of the prepared 8167** statements. For example, if the number of table steps greatly exceeds 8168** the number of table searches or result rows, that would tend to indicate 8169** that the prepared statement is using a full table scan rather than 8170** an index. 8171** 8172** ^(This interface is used to retrieve and reset counter values from 8173** a [prepared statement]. The first argument is the prepared statement 8174** object to be interrogated. The second argument 8175** is an integer code for a specific [SQLITE_STMTSTATUS counter] 8176** to be interrogated.)^ 8177** ^The current value of the requested counter is returned. 8178** ^If the resetFlg is true, then the counter is reset to zero after this 8179** interface call returns. 8180** 8181** See also: [sqlite3_status()] and [sqlite3_db_status()]. 8182*/ 8183int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 8184 8185/* 8186** CAPI3REF: Status Parameters for prepared statements 8187** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 8188** 8189** These preprocessor macros define integer codes that name counter 8190** values associated with the [sqlite3_stmt_status()] interface. 8191** The meanings of the various counters are as follows: 8192** 8193** <dl> 8194** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 8195** <dd>^This is the number of times that SQLite has stepped forward in 8196** a table as part of a full table scan. Large numbers for this counter 8197** may indicate opportunities for performance improvement through 8198** careful use of indices.</dd> 8199** 8200** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 8201** <dd>^This is the number of sort operations that have occurred. 8202** A non-zero value in this counter may indicate an opportunity to 8203** improvement performance through careful use of indices.</dd> 8204** 8205** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 8206** <dd>^This is the number of rows inserted into transient indices that 8207** were created automatically in order to help joins run faster. 8208** A non-zero value in this counter may indicate an opportunity to 8209** improvement performance by adding permanent indices that do not 8210** need to be reinitialized each time the statement is run.</dd> 8211** 8212** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 8213** <dd>^This is the number of virtual machine operations executed 8214** by the prepared statement if that number is less than or equal 8215** to 2147483647. The number of virtual machine operations can be 8216** used as a proxy for the total work done by the prepared statement. 8217** If the number of virtual machine operations exceeds 2147483647 8218** then the value returned by this statement status code is undefined. 8219** 8220** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 8221** <dd>^This is the number of times that the prepare statement has been 8222** automatically regenerated due to schema changes or changes to 8223** [bound parameters] that might affect the query plan. 8224** 8225** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 8226** <dd>^This is the number of times that the prepared statement has 8227** been run. A single "run" for the purposes of this counter is one 8228** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 8229** The counter is incremented on the first [sqlite3_step()] call of each 8230** cycle. 8231** 8232** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 8233** <dd>^This is the approximate number of bytes of heap memory 8234** used to store the prepared statement. ^This value is not actually 8235** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 8236** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 8237** </dd> 8238** </dl> 8239*/ 8240#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 8241#define SQLITE_STMTSTATUS_SORT 2 8242#define SQLITE_STMTSTATUS_AUTOINDEX 3 8243#define SQLITE_STMTSTATUS_VM_STEP 4 8244#define SQLITE_STMTSTATUS_REPREPARE 5 8245#define SQLITE_STMTSTATUS_RUN 6 8246#define SQLITE_STMTSTATUS_MEMUSED 99 8247 8248/* 8249** CAPI3REF: Custom Page Cache Object 8250** 8251** The sqlite3_pcache type is opaque. It is implemented by 8252** the pluggable module. The SQLite core has no knowledge of 8253** its size or internal structure and never deals with the 8254** sqlite3_pcache object except by holding and passing pointers 8255** to the object. 8256** 8257** See [sqlite3_pcache_methods2] for additional information. 8258*/ 8259typedef struct sqlite3_pcache sqlite3_pcache; 8260 8261/* 8262** CAPI3REF: Custom Page Cache Object 8263** 8264** The sqlite3_pcache_page object represents a single page in the 8265** page cache. The page cache will allocate instances of this 8266** object. Various methods of the page cache use pointers to instances 8267** of this object as parameters or as their return value. 8268** 8269** See [sqlite3_pcache_methods2] for additional information. 8270*/ 8271typedef struct sqlite3_pcache_page sqlite3_pcache_page; 8272struct sqlite3_pcache_page { 8273 void *pBuf; /* The content of the page */ 8274 void *pExtra; /* Extra information associated with the page */ 8275}; 8276 8277/* 8278** CAPI3REF: Application Defined Page Cache. 8279** KEYWORDS: {page cache} 8280** 8281** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 8282** register an alternative page cache implementation by passing in an 8283** instance of the sqlite3_pcache_methods2 structure.)^ 8284** In many applications, most of the heap memory allocated by 8285** SQLite is used for the page cache. 8286** By implementing a 8287** custom page cache using this API, an application can better control 8288** the amount of memory consumed by SQLite, the way in which 8289** that memory is allocated and released, and the policies used to 8290** determine exactly which parts of a database file are cached and for 8291** how long. 8292** 8293** The alternative page cache mechanism is an 8294** extreme measure that is only needed by the most demanding applications. 8295** The built-in page cache is recommended for most uses. 8296** 8297** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 8298** internal buffer by SQLite within the call to [sqlite3_config]. Hence 8299** the application may discard the parameter after the call to 8300** [sqlite3_config()] returns.)^ 8301** 8302** [[the xInit() page cache method]] 8303** ^(The xInit() method is called once for each effective 8304** call to [sqlite3_initialize()])^ 8305** (usually only once during the lifetime of the process). ^(The xInit() 8306** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 8307** The intent of the xInit() method is to set up global data structures 8308** required by the custom page cache implementation. 8309** ^(If the xInit() method is NULL, then the 8310** built-in default page cache is used instead of the application defined 8311** page cache.)^ 8312** 8313** [[the xShutdown() page cache method]] 8314** ^The xShutdown() method is called by [sqlite3_shutdown()]. 8315** It can be used to clean up 8316** any outstanding resources before process shutdown, if required. 8317** ^The xShutdown() method may be NULL. 8318** 8319** ^SQLite automatically serializes calls to the xInit method, 8320** so the xInit method need not be threadsafe. ^The 8321** xShutdown method is only called from [sqlite3_shutdown()] so it does 8322** not need to be threadsafe either. All other methods must be threadsafe 8323** in multithreaded applications. 8324** 8325** ^SQLite will never invoke xInit() more than once without an intervening 8326** call to xShutdown(). 8327** 8328** [[the xCreate() page cache methods]] 8329** ^SQLite invokes the xCreate() method to construct a new cache instance. 8330** SQLite will typically create one cache instance for each open database file, 8331** though this is not guaranteed. ^The 8332** first parameter, szPage, is the size in bytes of the pages that must 8333** be allocated by the cache. ^szPage will always a power of two. ^The 8334** second parameter szExtra is a number of bytes of extra storage 8335** associated with each page cache entry. ^The szExtra parameter will 8336** a number less than 250. SQLite will use the 8337** extra szExtra bytes on each page to store metadata about the underlying 8338** database page on disk. The value passed into szExtra depends 8339** on the SQLite version, the target platform, and how SQLite was compiled. 8340** ^The third argument to xCreate(), bPurgeable, is true if the cache being 8341** created will be used to cache database pages of a file stored on disk, or 8342** false if it is used for an in-memory database. The cache implementation 8343** does not have to do anything special based with the value of bPurgeable; 8344** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 8345** never invoke xUnpin() except to deliberately delete a page. 8346** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 8347** false will always have the "discard" flag set to true. 8348** ^Hence, a cache created with bPurgeable false will 8349** never contain any unpinned pages. 8350** 8351** [[the xCachesize() page cache method]] 8352** ^(The xCachesize() method may be called at any time by SQLite to set the 8353** suggested maximum cache-size (number of pages stored by) the cache 8354** instance passed as the first argument. This is the value configured using 8355** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 8356** parameter, the implementation is not required to do anything with this 8357** value; it is advisory only. 8358** 8359** [[the xPagecount() page cache methods]] 8360** The xPagecount() method must return the number of pages currently 8361** stored in the cache, both pinned and unpinned. 8362** 8363** [[the xFetch() page cache methods]] 8364** The xFetch() method locates a page in the cache and returns a pointer to 8365** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 8366** The pBuf element of the returned sqlite3_pcache_page object will be a 8367** pointer to a buffer of szPage bytes used to store the content of a 8368** single database page. The pExtra element of sqlite3_pcache_page will be 8369** a pointer to the szExtra bytes of extra storage that SQLite has requested 8370** for each entry in the page cache. 8371** 8372** The page to be fetched is determined by the key. ^The minimum key value 8373** is 1. After it has been retrieved using xFetch, the page is considered 8374** to be "pinned". 8375** 8376** If the requested page is already in the page cache, then the page cache 8377** implementation must return a pointer to the page buffer with its content 8378** intact. If the requested page is not already in the cache, then the 8379** cache implementation should use the value of the createFlag 8380** parameter to help it determined what action to take: 8381** 8382** <table border=1 width=85% align=center> 8383** <tr><th> createFlag <th> Behavior when page is not already in cache 8384** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 8385** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 8386** Otherwise return NULL. 8387** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 8388** NULL if allocating a new page is effectively impossible. 8389** </table> 8390** 8391** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 8392** will only use a createFlag of 2 after a prior call with a createFlag of 1 8393** failed.)^ In between the xFetch() calls, SQLite may 8394** attempt to unpin one or more cache pages by spilling the content of 8395** pinned pages to disk and synching the operating system disk cache. 8396** 8397** [[the xUnpin() page cache method]] 8398** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 8399** as its second argument. If the third parameter, discard, is non-zero, 8400** then the page must be evicted from the cache. 8401** ^If the discard parameter is 8402** zero, then the page may be discarded or retained at the discretion of 8403** page cache implementation. ^The page cache implementation 8404** may choose to evict unpinned pages at any time. 8405** 8406** The cache must not perform any reference counting. A single 8407** call to xUnpin() unpins the page regardless of the number of prior calls 8408** to xFetch(). 8409** 8410** [[the xRekey() page cache methods]] 8411** The xRekey() method is used to change the key value associated with the 8412** page passed as the second argument. If the cache 8413** previously contains an entry associated with newKey, it must be 8414** discarded. ^Any prior cache entry associated with newKey is guaranteed not 8415** to be pinned. 8416** 8417** When SQLite calls the xTruncate() method, the cache must discard all 8418** existing cache entries with page numbers (keys) greater than or equal 8419** to the value of the iLimit parameter passed to xTruncate(). If any 8420** of these pages are pinned, they are implicitly unpinned, meaning that 8421** they can be safely discarded. 8422** 8423** [[the xDestroy() page cache method]] 8424** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 8425** All resources associated with the specified cache should be freed. ^After 8426** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 8427** handle invalid, and will not use it with any other sqlite3_pcache_methods2 8428** functions. 8429** 8430** [[the xShrink() page cache method]] 8431** ^SQLite invokes the xShrink() method when it wants the page cache to 8432** free up as much of heap memory as possible. The page cache implementation 8433** is not obligated to free any memory, but well-behaved implementations should 8434** do their best. 8435*/ 8436typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 8437struct sqlite3_pcache_methods2 { 8438 int iVersion; 8439 void *pArg; 8440 int (*xInit)(void*); 8441 void (*xShutdown)(void*); 8442 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 8443 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8444 int (*xPagecount)(sqlite3_pcache*); 8445 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8446 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 8447 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 8448 unsigned oldKey, unsigned newKey); 8449 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8450 void (*xDestroy)(sqlite3_pcache*); 8451 void (*xShrink)(sqlite3_pcache*); 8452}; 8453 8454/* 8455** This is the obsolete pcache_methods object that has now been replaced 8456** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 8457** retained in the header file for backwards compatibility only. 8458*/ 8459typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 8460struct sqlite3_pcache_methods { 8461 void *pArg; 8462 int (*xInit)(void*); 8463 void (*xShutdown)(void*); 8464 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 8465 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8466 int (*xPagecount)(sqlite3_pcache*); 8467 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8468 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 8469 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 8470 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8471 void (*xDestroy)(sqlite3_pcache*); 8472}; 8473 8474 8475/* 8476** CAPI3REF: Online Backup Object 8477** 8478** The sqlite3_backup object records state information about an ongoing 8479** online backup operation. ^The sqlite3_backup object is created by 8480** a call to [sqlite3_backup_init()] and is destroyed by a call to 8481** [sqlite3_backup_finish()]. 8482** 8483** See Also: [Using the SQLite Online Backup API] 8484*/ 8485typedef struct sqlite3_backup sqlite3_backup; 8486 8487/* 8488** CAPI3REF: Online Backup API. 8489** 8490** The backup API copies the content of one database into another. 8491** It is useful either for creating backups of databases or 8492** for copying in-memory databases to or from persistent files. 8493** 8494** See Also: [Using the SQLite Online Backup API] 8495** 8496** ^SQLite holds a write transaction open on the destination database file 8497** for the duration of the backup operation. 8498** ^The source database is read-locked only while it is being read; 8499** it is not locked continuously for the entire backup operation. 8500** ^Thus, the backup may be performed on a live source database without 8501** preventing other database connections from 8502** reading or writing to the source database while the backup is underway. 8503** 8504** ^(To perform a backup operation: 8505** <ol> 8506** <li><b>sqlite3_backup_init()</b> is called once to initialize the 8507** backup, 8508** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 8509** the data between the two databases, and finally 8510** <li><b>sqlite3_backup_finish()</b> is called to release all resources 8511** associated with the backup operation. 8512** </ol>)^ 8513** There should be exactly one call to sqlite3_backup_finish() for each 8514** successful call to sqlite3_backup_init(). 8515** 8516** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 8517** 8518** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 8519** [database connection] associated with the destination database 8520** and the database name, respectively. 8521** ^The database name is "main" for the main database, "temp" for the 8522** temporary database, or the name specified after the AS keyword in 8523** an [ATTACH] statement for an attached database. 8524** ^The S and M arguments passed to 8525** sqlite3_backup_init(D,N,S,M) identify the [database connection] 8526** and database name of the source database, respectively. 8527** ^The source and destination [database connections] (parameters S and D) 8528** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 8529** an error. 8530** 8531** ^A call to sqlite3_backup_init() will fail, returning NULL, if 8532** there is already a read or read-write transaction open on the 8533** destination database. 8534** 8535** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 8536** returned and an error code and error message are stored in the 8537** destination [database connection] D. 8538** ^The error code and message for the failed call to sqlite3_backup_init() 8539** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 8540** [sqlite3_errmsg16()] functions. 8541** ^A successful call to sqlite3_backup_init() returns a pointer to an 8542** [sqlite3_backup] object. 8543** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 8544** sqlite3_backup_finish() functions to perform the specified backup 8545** operation. 8546** 8547** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 8548** 8549** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 8550** the source and destination databases specified by [sqlite3_backup] object B. 8551** ^If N is negative, all remaining source pages are copied. 8552** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 8553** are still more pages to be copied, then the function returns [SQLITE_OK]. 8554** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 8555** from source to destination, then it returns [SQLITE_DONE]. 8556** ^If an error occurs while running sqlite3_backup_step(B,N), 8557** then an [error code] is returned. ^As well as [SQLITE_OK] and 8558** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 8559** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 8560** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 8561** 8562** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 8563** <ol> 8564** <li> the destination database was opened read-only, or 8565** <li> the destination database is using write-ahead-log journaling 8566** and the destination and source page sizes differ, or 8567** <li> the destination database is an in-memory database and the 8568** destination and source page sizes differ. 8569** </ol>)^ 8570** 8571** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 8572** the [sqlite3_busy_handler | busy-handler function] 8573** is invoked (if one is specified). ^If the 8574** busy-handler returns non-zero before the lock is available, then 8575** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 8576** sqlite3_backup_step() can be retried later. ^If the source 8577** [database connection] 8578** is being used to write to the source database when sqlite3_backup_step() 8579** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 8580** case the call to sqlite3_backup_step() can be retried later on. ^(If 8581** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 8582** [SQLITE_READONLY] is returned, then 8583** there is no point in retrying the call to sqlite3_backup_step(). These 8584** errors are considered fatal.)^ The application must accept 8585** that the backup operation has failed and pass the backup operation handle 8586** to the sqlite3_backup_finish() to release associated resources. 8587** 8588** ^The first call to sqlite3_backup_step() obtains an exclusive lock 8589** on the destination file. ^The exclusive lock is not released until either 8590** sqlite3_backup_finish() is called or the backup operation is complete 8591** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 8592** sqlite3_backup_step() obtains a [shared lock] on the source database that 8593** lasts for the duration of the sqlite3_backup_step() call. 8594** ^Because the source database is not locked between calls to 8595** sqlite3_backup_step(), the source database may be modified mid-way 8596** through the backup process. ^If the source database is modified by an 8597** external process or via a database connection other than the one being 8598** used by the backup operation, then the backup will be automatically 8599** restarted by the next call to sqlite3_backup_step(). ^If the source 8600** database is modified by the using the same database connection as is used 8601** by the backup operation, then the backup database is automatically 8602** updated at the same time. 8603** 8604** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 8605** 8606** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 8607** application wishes to abandon the backup operation, the application 8608** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 8609** ^The sqlite3_backup_finish() interfaces releases all 8610** resources associated with the [sqlite3_backup] object. 8611** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 8612** active write-transaction on the destination database is rolled back. 8613** The [sqlite3_backup] object is invalid 8614** and may not be used following a call to sqlite3_backup_finish(). 8615** 8616** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 8617** sqlite3_backup_step() errors occurred, regardless or whether or not 8618** sqlite3_backup_step() completed. 8619** ^If an out-of-memory condition or IO error occurred during any prior 8620** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 8621** sqlite3_backup_finish() returns the corresponding [error code]. 8622** 8623** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 8624** is not a permanent error and does not affect the return value of 8625** sqlite3_backup_finish(). 8626** 8627** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 8628** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 8629** 8630** ^The sqlite3_backup_remaining() routine returns the number of pages still 8631** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 8632** ^The sqlite3_backup_pagecount() routine returns the total number of pages 8633** in the source database at the conclusion of the most recent 8634** sqlite3_backup_step(). 8635** ^(The values returned by these functions are only updated by 8636** sqlite3_backup_step(). If the source database is modified in a way that 8637** changes the size of the source database or the number of pages remaining, 8638** those changes are not reflected in the output of sqlite3_backup_pagecount() 8639** and sqlite3_backup_remaining() until after the next 8640** sqlite3_backup_step().)^ 8641** 8642** <b>Concurrent Usage of Database Handles</b> 8643** 8644** ^The source [database connection] may be used by the application for other 8645** purposes while a backup operation is underway or being initialized. 8646** ^If SQLite is compiled and configured to support threadsafe database 8647** connections, then the source database connection may be used concurrently 8648** from within other threads. 8649** 8650** However, the application must guarantee that the destination 8651** [database connection] is not passed to any other API (by any thread) after 8652** sqlite3_backup_init() is called and before the corresponding call to 8653** sqlite3_backup_finish(). SQLite does not currently check to see 8654** if the application incorrectly accesses the destination [database connection] 8655** and so no error code is reported, but the operations may malfunction 8656** nevertheless. Use of the destination database connection while a 8657** backup is in progress might also also cause a mutex deadlock. 8658** 8659** If running in [shared cache mode], the application must 8660** guarantee that the shared cache used by the destination database 8661** is not accessed while the backup is running. In practice this means 8662** that the application must guarantee that the disk file being 8663** backed up to is not accessed by any connection within the process, 8664** not just the specific connection that was passed to sqlite3_backup_init(). 8665** 8666** The [sqlite3_backup] object itself is partially threadsafe. Multiple 8667** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 8668** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 8669** APIs are not strictly speaking threadsafe. If they are invoked at the 8670** same time as another thread is invoking sqlite3_backup_step() it is 8671** possible that they return invalid values. 8672*/ 8673sqlite3_backup *sqlite3_backup_init( 8674 sqlite3 *pDest, /* Destination database handle */ 8675 const char *zDestName, /* Destination database name */ 8676 sqlite3 *pSource, /* Source database handle */ 8677 const char *zSourceName /* Source database name */ 8678); 8679int sqlite3_backup_step(sqlite3_backup *p, int nPage); 8680int sqlite3_backup_finish(sqlite3_backup *p); 8681int sqlite3_backup_remaining(sqlite3_backup *p); 8682int sqlite3_backup_pagecount(sqlite3_backup *p); 8683 8684/* 8685** CAPI3REF: Unlock Notification 8686** METHOD: sqlite3 8687** 8688** ^When running in shared-cache mode, a database operation may fail with 8689** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 8690** individual tables within the shared-cache cannot be obtained. See 8691** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 8692** ^This API may be used to register a callback that SQLite will invoke 8693** when the connection currently holding the required lock relinquishes it. 8694** ^This API is only available if the library was compiled with the 8695** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 8696** 8697** See Also: [Using the SQLite Unlock Notification Feature]. 8698** 8699** ^Shared-cache locks are released when a database connection concludes 8700** its current transaction, either by committing it or rolling it back. 8701** 8702** ^When a connection (known as the blocked connection) fails to obtain a 8703** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 8704** identity of the database connection (the blocking connection) that 8705** has locked the required resource is stored internally. ^After an 8706** application receives an SQLITE_LOCKED error, it may call the 8707** sqlite3_unlock_notify() method with the blocked connection handle as 8708** the first argument to register for a callback that will be invoked 8709** when the blocking connections current transaction is concluded. ^The 8710** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 8711** call that concludes the blocking connection's transaction. 8712** 8713** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 8714** there is a chance that the blocking connection will have already 8715** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 8716** If this happens, then the specified callback is invoked immediately, 8717** from within the call to sqlite3_unlock_notify().)^ 8718** 8719** ^If the blocked connection is attempting to obtain a write-lock on a 8720** shared-cache table, and more than one other connection currently holds 8721** a read-lock on the same table, then SQLite arbitrarily selects one of 8722** the other connections to use as the blocking connection. 8723** 8724** ^(There may be at most one unlock-notify callback registered by a 8725** blocked connection. If sqlite3_unlock_notify() is called when the 8726** blocked connection already has a registered unlock-notify callback, 8727** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 8728** called with a NULL pointer as its second argument, then any existing 8729** unlock-notify callback is canceled. ^The blocked connections 8730** unlock-notify callback may also be canceled by closing the blocked 8731** connection using [sqlite3_close()]. 8732** 8733** The unlock-notify callback is not reentrant. If an application invokes 8734** any sqlite3_xxx API functions from within an unlock-notify callback, a 8735** crash or deadlock may be the result. 8736** 8737** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 8738** returns SQLITE_OK. 8739** 8740** <b>Callback Invocation Details</b> 8741** 8742** When an unlock-notify callback is registered, the application provides a 8743** single void* pointer that is passed to the callback when it is invoked. 8744** However, the signature of the callback function allows SQLite to pass 8745** it an array of void* context pointers. The first argument passed to 8746** an unlock-notify callback is a pointer to an array of void* pointers, 8747** and the second is the number of entries in the array. 8748** 8749** When a blocking connection's transaction is concluded, there may be 8750** more than one blocked connection that has registered for an unlock-notify 8751** callback. ^If two or more such blocked connections have specified the 8752** same callback function, then instead of invoking the callback function 8753** multiple times, it is invoked once with the set of void* context pointers 8754** specified by the blocked connections bundled together into an array. 8755** This gives the application an opportunity to prioritize any actions 8756** related to the set of unblocked database connections. 8757** 8758** <b>Deadlock Detection</b> 8759** 8760** Assuming that after registering for an unlock-notify callback a 8761** database waits for the callback to be issued before taking any further 8762** action (a reasonable assumption), then using this API may cause the 8763** application to deadlock. For example, if connection X is waiting for 8764** connection Y's transaction to be concluded, and similarly connection 8765** Y is waiting on connection X's transaction, then neither connection 8766** will proceed and the system may remain deadlocked indefinitely. 8767** 8768** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 8769** detection. ^If a given call to sqlite3_unlock_notify() would put the 8770** system in a deadlocked state, then SQLITE_LOCKED is returned and no 8771** unlock-notify callback is registered. The system is said to be in 8772** a deadlocked state if connection A has registered for an unlock-notify 8773** callback on the conclusion of connection B's transaction, and connection 8774** B has itself registered for an unlock-notify callback when connection 8775** A's transaction is concluded. ^Indirect deadlock is also detected, so 8776** the system is also considered to be deadlocked if connection B has 8777** registered for an unlock-notify callback on the conclusion of connection 8778** C's transaction, where connection C is waiting on connection A. ^Any 8779** number of levels of indirection are allowed. 8780** 8781** <b>The "DROP TABLE" Exception</b> 8782** 8783** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 8784** always appropriate to call sqlite3_unlock_notify(). There is however, 8785** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 8786** SQLite checks if there are any currently executing SELECT statements 8787** that belong to the same connection. If there are, SQLITE_LOCKED is 8788** returned. In this case there is no "blocking connection", so invoking 8789** sqlite3_unlock_notify() results in the unlock-notify callback being 8790** invoked immediately. If the application then re-attempts the "DROP TABLE" 8791** or "DROP INDEX" query, an infinite loop might be the result. 8792** 8793** One way around this problem is to check the extended error code returned 8794** by an sqlite3_step() call. ^(If there is a blocking connection, then the 8795** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 8796** the special "DROP TABLE/INDEX" case, the extended error code is just 8797** SQLITE_LOCKED.)^ 8798*/ 8799int sqlite3_unlock_notify( 8800 sqlite3 *pBlocked, /* Waiting connection */ 8801 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 8802 void *pNotifyArg /* Argument to pass to xNotify */ 8803); 8804 8805 8806/* 8807** CAPI3REF: String Comparison 8808** 8809** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 8810** and extensions to compare the contents of two buffers containing UTF-8 8811** strings in a case-independent fashion, using the same definition of "case 8812** independence" that SQLite uses internally when comparing identifiers. 8813*/ 8814int sqlite3_stricmp(const char *, const char *); 8815int sqlite3_strnicmp(const char *, const char *, int); 8816 8817/* 8818** CAPI3REF: String Globbing 8819* 8820** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 8821** string X matches the [GLOB] pattern P. 8822** ^The definition of [GLOB] pattern matching used in 8823** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 8824** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 8825** is case sensitive. 8826** 8827** Note that this routine returns zero on a match and non-zero if the strings 8828** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8829** 8830** See also: [sqlite3_strlike()]. 8831*/ 8832int sqlite3_strglob(const char *zGlob, const char *zStr); 8833 8834/* 8835** CAPI3REF: String LIKE Matching 8836* 8837** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 8838** string X matches the [LIKE] pattern P with escape character E. 8839** ^The definition of [LIKE] pattern matching used in 8840** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 8841** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 8842** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 8843** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 8844** insensitive - equivalent upper and lower case ASCII characters match 8845** one another. 8846** 8847** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 8848** only ASCII characters are case folded. 8849** 8850** Note that this routine returns zero on a match and non-zero if the strings 8851** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8852** 8853** See also: [sqlite3_strglob()]. 8854*/ 8855int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8856 8857/* 8858** CAPI3REF: Error Logging Interface 8859** 8860** ^The [sqlite3_log()] interface writes a message into the [error log] 8861** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8862** ^If logging is enabled, the zFormat string and subsequent arguments are 8863** used with [sqlite3_snprintf()] to generate the final output string. 8864** 8865** The sqlite3_log() interface is intended for use by extensions such as 8866** virtual tables, collating functions, and SQL functions. While there is 8867** nothing to prevent an application from calling sqlite3_log(), doing so 8868** is considered bad form. 8869** 8870** The zFormat string must not be NULL. 8871** 8872** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8873** will not use dynamically allocated memory. The log message is stored in 8874** a fixed-length buffer on the stack. If the log message is longer than 8875** a few hundred characters, it will be truncated to the length of the 8876** buffer. 8877*/ 8878void sqlite3_log(int iErrCode, const char *zFormat, ...); 8879 8880/* 8881** CAPI3REF: Write-Ahead Log Commit Hook 8882** METHOD: sqlite3 8883** 8884** ^The [sqlite3_wal_hook()] function is used to register a callback that 8885** is invoked each time data is committed to a database in wal mode. 8886** 8887** ^(The callback is invoked by SQLite after the commit has taken place and 8888** the associated write-lock on the database released)^, so the implementation 8889** may read, write or [checkpoint] the database as required. 8890** 8891** ^The first parameter passed to the callback function when it is invoked 8892** is a copy of the third parameter passed to sqlite3_wal_hook() when 8893** registering the callback. ^The second is a copy of the database handle. 8894** ^The third parameter is the name of the database that was written to - 8895** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8896** is the number of pages currently in the write-ahead log file, 8897** including those that were just committed. 8898** 8899** The callback function should normally return [SQLITE_OK]. ^If an error 8900** code is returned, that error will propagate back up through the 8901** SQLite code base to cause the statement that provoked the callback 8902** to report an error, though the commit will have still occurred. If the 8903** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8904** that does not correspond to any valid SQLite error code, the results 8905** are undefined. 8906** 8907** A single database handle may have at most a single write-ahead log callback 8908** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8909** previously registered write-ahead log callback. ^Note that the 8910** [sqlite3_wal_autocheckpoint()] interface and the 8911** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8912** overwrite any prior [sqlite3_wal_hook()] settings. 8913*/ 8914void *sqlite3_wal_hook( 8915 sqlite3*, 8916 int(*)(void *,sqlite3*,const char*,int), 8917 void* 8918); 8919 8920/* 8921** CAPI3REF: Configure an auto-checkpoint 8922** METHOD: sqlite3 8923** 8924** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8925** [sqlite3_wal_hook()] that causes any database on [database connection] D 8926** to automatically [checkpoint] 8927** after committing a transaction if there are N or 8928** more frames in the [write-ahead log] file. ^Passing zero or 8929** a negative value as the nFrame parameter disables automatic 8930** checkpoints entirely. 8931** 8932** ^The callback registered by this function replaces any existing callback 8933** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8934** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8935** configured by this function. 8936** 8937** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8938** from SQL. 8939** 8940** ^Checkpoints initiated by this mechanism are 8941** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8942** 8943** ^Every new [database connection] defaults to having the auto-checkpoint 8944** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8945** pages. The use of this interface 8946** is only necessary if the default setting is found to be suboptimal 8947** for a particular application. 8948*/ 8949int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8950 8951/* 8952** CAPI3REF: Checkpoint a database 8953** METHOD: sqlite3 8954** 8955** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8956** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8957** 8958** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8959** [write-ahead log] for database X on [database connection] D to be 8960** transferred into the database file and for the write-ahead log to 8961** be reset. See the [checkpointing] documentation for addition 8962** information. 8963** 8964** This interface used to be the only way to cause a checkpoint to 8965** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8966** interface was added. This interface is retained for backwards 8967** compatibility and as a convenience for applications that need to manually 8968** start a callback but which do not need the full power (and corresponding 8969** complication) of [sqlite3_wal_checkpoint_v2()]. 8970*/ 8971int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8972 8973/* 8974** CAPI3REF: Checkpoint a database 8975** METHOD: sqlite3 8976** 8977** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8978** operation on database X of [database connection] D in mode M. Status 8979** information is written back into integers pointed to by L and C.)^ 8980** ^(The M parameter must be a valid [checkpoint mode]:)^ 8981** 8982** <dl> 8983** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8984** ^Checkpoint as many frames as possible without waiting for any database 8985** readers or writers to finish, then sync the database file if all frames 8986** in the log were checkpointed. ^The [busy-handler callback] 8987** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8988** ^On the other hand, passive mode might leave the checkpoint unfinished 8989** if there are concurrent readers or writers. 8990** 8991** <dt>SQLITE_CHECKPOINT_FULL<dd> 8992** ^This mode blocks (it invokes the 8993** [sqlite3_busy_handler|busy-handler callback]) until there is no 8994** database writer and all readers are reading from the most recent database 8995** snapshot. ^It then checkpoints all frames in the log file and syncs the 8996** database file. ^This mode blocks new database writers while it is pending, 8997** but new database readers are allowed to continue unimpeded. 8998** 8999** <dt>SQLITE_CHECKPOINT_RESTART<dd> 9000** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 9001** that after checkpointing the log file it blocks (calls the 9002** [busy-handler callback]) 9003** until all readers are reading from the database file only. ^This ensures 9004** that the next writer will restart the log file from the beginning. 9005** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 9006** database writer attempts while it is pending, but does not impede readers. 9007** 9008** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 9009** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 9010** addition that it also truncates the log file to zero bytes just prior 9011** to a successful return. 9012** </dl> 9013** 9014** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 9015** the log file or to -1 if the checkpoint could not run because 9016** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 9017** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 9018** log file (including any that were already checkpointed before the function 9019** was called) or to -1 if the checkpoint could not run due to an error or 9020** because the database is not in WAL mode. ^Note that upon successful 9021** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 9022** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 9023** 9024** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 9025** any other process is running a checkpoint operation at the same time, the 9026** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 9027** busy-handler configured, it will not be invoked in this case. 9028** 9029** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 9030** exclusive "writer" lock on the database file. ^If the writer lock cannot be 9031** obtained immediately, and a busy-handler is configured, it is invoked and 9032** the writer lock retried until either the busy-handler returns 0 or the lock 9033** is successfully obtained. ^The busy-handler is also invoked while waiting for 9034** database readers as described above. ^If the busy-handler returns 0 before 9035** the writer lock is obtained or while waiting for database readers, the 9036** checkpoint operation proceeds from that point in the same way as 9037** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 9038** without blocking any further. ^SQLITE_BUSY is returned in this case. 9039** 9040** ^If parameter zDb is NULL or points to a zero length string, then the 9041** specified operation is attempted on all WAL databases [attached] to 9042** [database connection] db. In this case the 9043** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 9044** an SQLITE_BUSY error is encountered when processing one or more of the 9045** attached WAL databases, the operation is still attempted on any remaining 9046** attached databases and SQLITE_BUSY is returned at the end. ^If any other 9047** error occurs while processing an attached database, processing is abandoned 9048** and the error code is returned to the caller immediately. ^If no error 9049** (SQLITE_BUSY or otherwise) is encountered while processing the attached 9050** databases, SQLITE_OK is returned. 9051** 9052** ^If database zDb is the name of an attached database that is not in WAL 9053** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 9054** zDb is not NULL (or a zero length string) and is not the name of any 9055** attached database, SQLITE_ERROR is returned to the caller. 9056** 9057** ^Unless it returns SQLITE_MISUSE, 9058** the sqlite3_wal_checkpoint_v2() interface 9059** sets the error information that is queried by 9060** [sqlite3_errcode()] and [sqlite3_errmsg()]. 9061** 9062** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 9063** from SQL. 9064*/ 9065int sqlite3_wal_checkpoint_v2( 9066 sqlite3 *db, /* Database handle */ 9067 const char *zDb, /* Name of attached database (or NULL) */ 9068 int eMode, /* SQLITE_CHECKPOINT_* value */ 9069 int *pnLog, /* OUT: Size of WAL log in frames */ 9070 int *pnCkpt /* OUT: Total number of frames checkpointed */ 9071); 9072 9073/* 9074** CAPI3REF: Checkpoint Mode Values 9075** KEYWORDS: {checkpoint mode} 9076** 9077** These constants define all valid values for the "checkpoint mode" passed 9078** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 9079** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 9080** meaning of each of these checkpoint modes. 9081*/ 9082#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 9083#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 9084#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 9085#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 9086 9087/* 9088** CAPI3REF: Virtual Table Interface Configuration 9089** 9090** This function may be called by either the [xConnect] or [xCreate] method 9091** of a [virtual table] implementation to configure 9092** various facets of the virtual table interface. 9093** 9094** If this interface is invoked outside the context of an xConnect or 9095** xCreate virtual table method then the behavior is undefined. 9096** 9097** In the call sqlite3_vtab_config(D,C,...) the D parameter is the 9098** [database connection] in which the virtual table is being created and 9099** which is passed in as the first argument to the [xConnect] or [xCreate] 9100** method that is invoking sqlite3_vtab_config(). The C parameter is one 9101** of the [virtual table configuration options]. The presence and meaning 9102** of parameters after C depend on which [virtual table configuration option] 9103** is used. 9104*/ 9105int sqlite3_vtab_config(sqlite3*, int op, ...); 9106 9107/* 9108** CAPI3REF: Virtual Table Configuration Options 9109** KEYWORDS: {virtual table configuration options} 9110** KEYWORDS: {virtual table configuration option} 9111** 9112** These macros define the various options to the 9113** [sqlite3_vtab_config()] interface that [virtual table] implementations 9114** can use to customize and optimize their behavior. 9115** 9116** <dl> 9117** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]] 9118** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt> 9119** <dd>Calls of the form 9120** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 9121** where X is an integer. If X is zero, then the [virtual table] whose 9122** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 9123** support constraints. In this configuration (which is the default) if 9124** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 9125** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 9126** specified as part of the users SQL statement, regardless of the actual 9127** ON CONFLICT mode specified. 9128** 9129** If X is non-zero, then the virtual table implementation guarantees 9130** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 9131** any modifications to internal or persistent data structures have been made. 9132** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 9133** is able to roll back a statement or database transaction, and abandon 9134** or continue processing the current SQL statement as appropriate. 9135** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 9136** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 9137** had been ABORT. 9138** 9139** Virtual table implementations that are required to handle OR REPLACE 9140** must do so within the [xUpdate] method. If a call to the 9141** [sqlite3_vtab_on_conflict()] function indicates that the current ON 9142** CONFLICT policy is REPLACE, the virtual table implementation should 9143** silently replace the appropriate rows within the xUpdate callback and 9144** return SQLITE_OK. Or, if this is not possible, it may return 9145** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 9146** constraint handling. 9147** </dd> 9148** 9149** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt> 9150** <dd>Calls of the form 9151** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the 9152** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9153** prohibits that virtual table from being used from within triggers and 9154** views. 9155** </dd> 9156** 9157** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt> 9158** <dd>Calls of the form 9159** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the 9160** the [xConnect] or [xCreate] methods of a [virtual table] implmentation 9161** identify that virtual table as being safe to use from within triggers 9162** and views. Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the 9163** virtual table can do no serious harm even if it is controlled by a 9164** malicious hacker. Developers should avoid setting the SQLITE_VTAB_INNOCUOUS 9165** flag unless absolutely necessary. 9166** </dd> 9167** </dl> 9168*/ 9169#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 9170#define SQLITE_VTAB_INNOCUOUS 2 9171#define SQLITE_VTAB_DIRECTONLY 3 9172 9173/* 9174** CAPI3REF: Determine The Virtual Table Conflict Policy 9175** 9176** This function may only be called from within a call to the [xUpdate] method 9177** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 9178** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 9179** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 9180** of the SQL statement that triggered the call to the [xUpdate] method of the 9181** [virtual table]. 9182*/ 9183int sqlite3_vtab_on_conflict(sqlite3 *); 9184 9185/* 9186** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 9187** 9188** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 9189** method of a [virtual table], then it returns true if and only if the 9190** column is being fetched as part of an UPDATE operation during which the 9191** column value will not change. Applications might use this to substitute 9192** a return value that is less expensive to compute and that the corresponding 9193** [xUpdate] method understands as a "no-change" value. 9194** 9195** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 9196** the column is not changed by the UPDATE statement, then the xColumn 9197** method can optionally return without setting a result, without calling 9198** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 9199** In that case, [sqlite3_value_nochange(X)] will return true for the 9200** same column in the [xUpdate] method. 9201*/ 9202int sqlite3_vtab_nochange(sqlite3_context*); 9203 9204/* 9205** CAPI3REF: Determine The Collation For a Virtual Table Constraint 9206** 9207** This function may only be called from within a call to the [xBestIndex] 9208** method of a [virtual table]. 9209** 9210** The first argument must be the sqlite3_index_info object that is the 9211** first parameter to the xBestIndex() method. The second argument must be 9212** an index into the aConstraint[] array belonging to the sqlite3_index_info 9213** structure passed to xBestIndex. This function returns a pointer to a buffer 9214** containing the name of the collation sequence for the corresponding 9215** constraint. 9216*/ 9217SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 9218 9219/* 9220** CAPI3REF: Conflict resolution modes 9221** KEYWORDS: {conflict resolution mode} 9222** 9223** These constants are returned by [sqlite3_vtab_on_conflict()] to 9224** inform a [virtual table] implementation what the [ON CONFLICT] mode 9225** is for the SQL statement being evaluated. 9226** 9227** Note that the [SQLITE_IGNORE] constant is also used as a potential 9228** return value from the [sqlite3_set_authorizer()] callback and that 9229** [SQLITE_ABORT] is also a [result code]. 9230*/ 9231#define SQLITE_ROLLBACK 1 9232/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 9233#define SQLITE_FAIL 3 9234/* #define SQLITE_ABORT 4 // Also an error code */ 9235#define SQLITE_REPLACE 5 9236 9237/* 9238** CAPI3REF: Prepared Statement Scan Status Opcodes 9239** KEYWORDS: {scanstatus options} 9240** 9241** The following constants can be used for the T parameter to the 9242** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 9243** different metric for sqlite3_stmt_scanstatus() to return. 9244** 9245** When the value returned to V is a string, space to hold that string is 9246** managed by the prepared statement S and will be automatically freed when 9247** S is finalized. 9248** 9249** <dl> 9250** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 9251** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be 9252** set to the total number of times that the X-th loop has run.</dd> 9253** 9254** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 9255** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set 9256** to the total number of rows examined by all iterations of the X-th loop.</dd> 9257** 9258** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 9259** <dd>^The "double" variable pointed to by the V parameter will be set to the 9260** query planner's estimate for the average number of rows output from each 9261** iteration of the X-th loop. If the query planner's estimates was accurate, 9262** then this value will approximate the quotient NVISIT/NLOOP and the 9263** product of this value for all prior loops with the same SELECTID will 9264** be the NLOOP value for the current loop. 9265** 9266** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 9267** <dd>^The "const char *" variable pointed to by the V parameter will be set 9268** to a zero-terminated UTF-8 string containing the name of the index or table 9269** used for the X-th loop. 9270** 9271** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 9272** <dd>^The "const char *" variable pointed to by the V parameter will be set 9273** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 9274** description for the X-th loop. 9275** 9276** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 9277** <dd>^The "int" variable pointed to by the V parameter will be set to the 9278** "select-id" for the X-th loop. The select-id identifies which query or 9279** subquery the loop is part of. The main query has a select-id of zero. 9280** The select-id is the same value as is output in the first column 9281** of an [EXPLAIN QUERY PLAN] query. 9282** </dl> 9283*/ 9284#define SQLITE_SCANSTAT_NLOOP 0 9285#define SQLITE_SCANSTAT_NVISIT 1 9286#define SQLITE_SCANSTAT_EST 2 9287#define SQLITE_SCANSTAT_NAME 3 9288#define SQLITE_SCANSTAT_EXPLAIN 4 9289#define SQLITE_SCANSTAT_SELECTID 5 9290 9291/* 9292** CAPI3REF: Prepared Statement Scan Status 9293** METHOD: sqlite3_stmt 9294** 9295** This interface returns information about the predicted and measured 9296** performance for pStmt. Advanced applications can use this 9297** interface to compare the predicted and the measured performance and 9298** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 9299** 9300** Since this interface is expected to be rarely used, it is only 9301** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 9302** compile-time option. 9303** 9304** The "iScanStatusOp" parameter determines which status information to return. 9305** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 9306** of this interface is undefined. 9307** ^The requested measurement is written into a variable pointed to by 9308** the "pOut" parameter. 9309** Parameter "idx" identifies the specific loop to retrieve statistics for. 9310** Loops are numbered starting from zero. ^If idx is out of range - less than 9311** zero or greater than or equal to the total number of loops used to implement 9312** the statement - a non-zero value is returned and the variable that pOut 9313** points to is unchanged. 9314** 9315** ^Statistics might not be available for all loops in all statements. ^In cases 9316** where there exist loops with no available statistics, this function behaves 9317** as if the loop did not exist - it returns non-zero and leave the variable 9318** that pOut points to unchanged. 9319** 9320** See also: [sqlite3_stmt_scanstatus_reset()] 9321*/ 9322int sqlite3_stmt_scanstatus( 9323 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 9324 int idx, /* Index of loop to report on */ 9325 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 9326 void *pOut /* Result written here */ 9327); 9328 9329/* 9330** CAPI3REF: Zero Scan-Status Counters 9331** METHOD: sqlite3_stmt 9332** 9333** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 9334** 9335** This API is only available if the library is built with pre-processor 9336** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 9337*/ 9338void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 9339 9340/* 9341** CAPI3REF: Flush caches to disk mid-transaction 9342** 9343** ^If a write-transaction is open on [database connection] D when the 9344** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 9345** pages in the pager-cache that are not currently in use are written out 9346** to disk. A dirty page may be in use if a database cursor created by an 9347** active SQL statement is reading from it, or if it is page 1 of a database 9348** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 9349** interface flushes caches for all schemas - "main", "temp", and 9350** any [attached] databases. 9351** 9352** ^If this function needs to obtain extra database locks before dirty pages 9353** can be flushed to disk, it does so. ^If those locks cannot be obtained 9354** immediately and there is a busy-handler callback configured, it is invoked 9355** in the usual manner. ^If the required lock still cannot be obtained, then 9356** the database is skipped and an attempt made to flush any dirty pages 9357** belonging to the next (if any) database. ^If any databases are skipped 9358** because locks cannot be obtained, but no other error occurs, this 9359** function returns SQLITE_BUSY. 9360** 9361** ^If any other error occurs while flushing dirty pages to disk (for 9362** example an IO error or out-of-memory condition), then processing is 9363** abandoned and an SQLite [error code] is returned to the caller immediately. 9364** 9365** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 9366** 9367** ^This function does not set the database handle error code or message 9368** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 9369*/ 9370int sqlite3_db_cacheflush(sqlite3*); 9371 9372/* 9373** CAPI3REF: The pre-update hook. 9374** 9375** ^These interfaces are only available if SQLite is compiled using the 9376** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 9377** 9378** ^The [sqlite3_preupdate_hook()] interface registers a callback function 9379** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 9380** on a database table. 9381** ^At most one preupdate hook may be registered at a time on a single 9382** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 9383** the previous setting. 9384** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 9385** with a NULL pointer as the second parameter. 9386** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 9387** the first parameter to callbacks. 9388** 9389** ^The preupdate hook only fires for changes to real database tables; the 9390** preupdate hook is not invoked for changes to [virtual tables] or to 9391** system tables like sqlite_master or sqlite_stat1. 9392** 9393** ^The second parameter to the preupdate callback is a pointer to 9394** the [database connection] that registered the preupdate hook. 9395** ^The third parameter to the preupdate callback is one of the constants 9396** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 9397** kind of update operation that is about to occur. 9398** ^(The fourth parameter to the preupdate callback is the name of the 9399** database within the database connection that is being modified. This 9400** will be "main" for the main database or "temp" for TEMP tables or 9401** the name given after the AS keyword in the [ATTACH] statement for attached 9402** databases.)^ 9403** ^The fifth parameter to the preupdate callback is the name of the 9404** table that is being modified. 9405** 9406** For an UPDATE or DELETE operation on a [rowid table], the sixth 9407** parameter passed to the preupdate callback is the initial [rowid] of the 9408** row being modified or deleted. For an INSERT operation on a rowid table, 9409** or any operation on a WITHOUT ROWID table, the value of the sixth 9410** parameter is undefined. For an INSERT or UPDATE on a rowid table the 9411** seventh parameter is the final rowid value of the row being inserted 9412** or updated. The value of the seventh parameter passed to the callback 9413** function is not defined for operations on WITHOUT ROWID tables, or for 9414** INSERT operations on rowid tables. 9415** 9416** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 9417** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 9418** provide additional information about a preupdate event. These routines 9419** may only be called from within a preupdate callback. Invoking any of 9420** these routines from outside of a preupdate callback or with a 9421** [database connection] pointer that is different from the one supplied 9422** to the preupdate callback results in undefined and probably undesirable 9423** behavior. 9424** 9425** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 9426** in the row that is being inserted, updated, or deleted. 9427** 9428** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 9429** a [protected sqlite3_value] that contains the value of the Nth column of 9430** the table row before it is updated. The N parameter must be between 0 9431** and one less than the number of columns or the behavior will be 9432** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 9433** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 9434** behavior is undefined. The [sqlite3_value] that P points to 9435** will be destroyed when the preupdate callback returns. 9436** 9437** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 9438** a [protected sqlite3_value] that contains the value of the Nth column of 9439** the table row after it is updated. The N parameter must be between 0 9440** and one less than the number of columns or the behavior will be 9441** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 9442** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 9443** behavior is undefined. The [sqlite3_value] that P points to 9444** will be destroyed when the preupdate callback returns. 9445** 9446** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 9447** callback was invoked as a result of a direct insert, update, or delete 9448** operation; or 1 for inserts, updates, or deletes invoked by top-level 9449** triggers; or 2 for changes resulting from triggers called by top-level 9450** triggers; and so forth. 9451** 9452** See also: [sqlite3_update_hook()] 9453*/ 9454#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 9455void *sqlite3_preupdate_hook( 9456 sqlite3 *db, 9457 void(*xPreUpdate)( 9458 void *pCtx, /* Copy of third arg to preupdate_hook() */ 9459 sqlite3 *db, /* Database handle */ 9460 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 9461 char const *zDb, /* Database name */ 9462 char const *zName, /* Table name */ 9463 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 9464 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 9465 ), 9466 void* 9467); 9468int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 9469int sqlite3_preupdate_count(sqlite3 *); 9470int sqlite3_preupdate_depth(sqlite3 *); 9471int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 9472#endif 9473 9474/* 9475** CAPI3REF: Low-level system error code 9476** 9477** ^Attempt to return the underlying operating system error code or error 9478** number that caused the most recent I/O error or failure to open a file. 9479** The return value is OS-dependent. For example, on unix systems, after 9480** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 9481** called to get back the underlying "errno" that caused the problem, such 9482** as ENOSPC, EAUTH, EISDIR, and so forth. 9483*/ 9484int sqlite3_system_errno(sqlite3*); 9485 9486/* 9487** CAPI3REF: Database Snapshot 9488** KEYWORDS: {snapshot} {sqlite3_snapshot} 9489** 9490** An instance of the snapshot object records the state of a [WAL mode] 9491** database for some specific point in history. 9492** 9493** In [WAL mode], multiple [database connections] that are open on the 9494** same database file can each be reading a different historical version 9495** of the database file. When a [database connection] begins a read 9496** transaction, that connection sees an unchanging copy of the database 9497** as it existed for the point in time when the transaction first started. 9498** Subsequent changes to the database from other connections are not seen 9499** by the reader until a new read transaction is started. 9500** 9501** The sqlite3_snapshot object records state information about an historical 9502** version of the database file so that it is possible to later open a new read 9503** transaction that sees that historical version of the database rather than 9504** the most recent version. 9505*/ 9506typedef struct sqlite3_snapshot { 9507 unsigned char hidden[48]; 9508} sqlite3_snapshot; 9509 9510/* 9511** CAPI3REF: Record A Database Snapshot 9512** CONSTRUCTOR: sqlite3_snapshot 9513** 9514** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 9515** new [sqlite3_snapshot] object that records the current state of 9516** schema S in database connection D. ^On success, the 9517** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 9518** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 9519** If there is not already a read-transaction open on schema S when 9520** this function is called, one is opened automatically. 9521** 9522** The following must be true for this function to succeed. If any of 9523** the following statements are false when sqlite3_snapshot_get() is 9524** called, SQLITE_ERROR is returned. The final value of *P is undefined 9525** in this case. 9526** 9527** <ul> 9528** <li> The database handle must not be in [autocommit mode]. 9529** 9530** <li> Schema S of [database connection] D must be a [WAL mode] database. 9531** 9532** <li> There must not be a write transaction open on schema S of database 9533** connection D. 9534** 9535** <li> One or more transactions must have been written to the current wal 9536** file since it was created on disk (by any connection). This means 9537** that a snapshot cannot be taken on a wal mode database with no wal 9538** file immediately after it is first opened. At least one transaction 9539** must be written to it first. 9540** </ul> 9541** 9542** This function may also return SQLITE_NOMEM. If it is called with the 9543** database handle in autocommit mode but fails for some other reason, 9544** whether or not a read transaction is opened on schema S is undefined. 9545** 9546** The [sqlite3_snapshot] object returned from a successful call to 9547** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 9548** to avoid a memory leak. 9549** 9550** The [sqlite3_snapshot_get()] interface is only available when the 9551** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9552*/ 9553SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 9554 sqlite3 *db, 9555 const char *zSchema, 9556 sqlite3_snapshot **ppSnapshot 9557); 9558 9559/* 9560** CAPI3REF: Start a read transaction on an historical snapshot 9561** METHOD: sqlite3_snapshot 9562** 9563** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read 9564** transaction or upgrades an existing one for schema S of 9565** [database connection] D such that the read transaction refers to 9566** historical [snapshot] P, rather than the most recent change to the 9567** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK 9568** on success or an appropriate [error code] if it fails. 9569** 9570** ^In order to succeed, the database connection must not be in 9571** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there 9572** is already a read transaction open on schema S, then the database handle 9573** must have no active statements (SELECT statements that have been passed 9574** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()). 9575** SQLITE_ERROR is returned if either of these conditions is violated, or 9576** if schema S does not exist, or if the snapshot object is invalid. 9577** 9578** ^A call to sqlite3_snapshot_open() will fail to open if the specified 9579** snapshot has been overwritten by a [checkpoint]. In this case 9580** SQLITE_ERROR_SNAPSHOT is returned. 9581** 9582** If there is already a read transaction open when this function is 9583** invoked, then the same read transaction remains open (on the same 9584** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT 9585** is returned. If another error code - for example SQLITE_PROTOCOL or an 9586** SQLITE_IOERR error code - is returned, then the final state of the 9587** read transaction is undefined. If SQLITE_OK is returned, then the 9588** read transaction is now open on database snapshot P. 9589** 9590** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 9591** database connection D does not know that the database file for 9592** schema S is in [WAL mode]. A database connection might not know 9593** that the database file is in [WAL mode] if there has been no prior 9594** I/O on that database connection, or if the database entered [WAL mode] 9595** after the most recent I/O on the database connection.)^ 9596** (Hint: Run "[PRAGMA application_id]" against a newly opened 9597** database connection in order to make it ready to use snapshots.) 9598** 9599** The [sqlite3_snapshot_open()] interface is only available when the 9600** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9601*/ 9602SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 9603 sqlite3 *db, 9604 const char *zSchema, 9605 sqlite3_snapshot *pSnapshot 9606); 9607 9608/* 9609** CAPI3REF: Destroy a snapshot 9610** DESTRUCTOR: sqlite3_snapshot 9611** 9612** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 9613** The application must eventually free every [sqlite3_snapshot] object 9614** using this routine to avoid a memory leak. 9615** 9616** The [sqlite3_snapshot_free()] interface is only available when the 9617** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9618*/ 9619SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 9620 9621/* 9622** CAPI3REF: Compare the ages of two snapshot handles. 9623** METHOD: sqlite3_snapshot 9624** 9625** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 9626** of two valid snapshot handles. 9627** 9628** If the two snapshot handles are not associated with the same database 9629** file, the result of the comparison is undefined. 9630** 9631** Additionally, the result of the comparison is only valid if both of the 9632** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 9633** last time the wal file was deleted. The wal file is deleted when the 9634** database is changed back to rollback mode or when the number of database 9635** clients drops to zero. If either snapshot handle was obtained before the 9636** wal file was last deleted, the value returned by this function 9637** is undefined. 9638** 9639** Otherwise, this API returns a negative value if P1 refers to an older 9640** snapshot than P2, zero if the two handles refer to the same database 9641** snapshot, and a positive value if P1 is a newer snapshot than P2. 9642** 9643** This interface is only available if SQLite is compiled with the 9644** [SQLITE_ENABLE_SNAPSHOT] option. 9645*/ 9646SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 9647 sqlite3_snapshot *p1, 9648 sqlite3_snapshot *p2 9649); 9650 9651/* 9652** CAPI3REF: Recover snapshots from a wal file 9653** METHOD: sqlite3_snapshot 9654** 9655** If a [WAL file] remains on disk after all database connections close 9656** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control] 9657** or because the last process to have the database opened exited without 9658** calling [sqlite3_close()]) and a new connection is subsequently opened 9659** on that database and [WAL file], the [sqlite3_snapshot_open()] interface 9660** will only be able to open the last transaction added to the WAL file 9661** even though the WAL file contains other valid transactions. 9662** 9663** This function attempts to scan the WAL file associated with database zDb 9664** of database handle db and make all valid snapshots available to 9665** sqlite3_snapshot_open(). It is an error if there is already a read 9666** transaction open on the database, or if the database is not a WAL mode 9667** database. 9668** 9669** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 9670** 9671** This interface is only available if SQLite is compiled with the 9672** [SQLITE_ENABLE_SNAPSHOT] option. 9673*/ 9674SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 9675 9676/* 9677** CAPI3REF: Serialize a database 9678** 9679** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 9680** that is a serialization of the S database on [database connection] D. 9681** If P is not a NULL pointer, then the size of the database in bytes 9682** is written into *P. 9683** 9684** For an ordinary on-disk database file, the serialization is just a 9685** copy of the disk file. For an in-memory database or a "TEMP" database, 9686** the serialization is the same sequence of bytes which would be written 9687** to disk if that database where backed up to disk. 9688** 9689** The usual case is that sqlite3_serialize() copies the serialization of 9690** the database into memory obtained from [sqlite3_malloc64()] and returns 9691** a pointer to that memory. The caller is responsible for freeing the 9692** returned value to avoid a memory leak. However, if the F argument 9693** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 9694** are made, and the sqlite3_serialize() function will return a pointer 9695** to the contiguous memory representation of the database that SQLite 9696** is currently using for that database, or NULL if the no such contiguous 9697** memory representation of the database exists. A contiguous memory 9698** representation of the database will usually only exist if there has 9699** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 9700** values of D and S. 9701** The size of the database is written into *P even if the 9702** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy 9703** of the database exists. 9704** 9705** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 9706** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 9707** allocation error occurs. 9708** 9709** This interface is only available if SQLite is compiled with the 9710** [SQLITE_ENABLE_DESERIALIZE] option. 9711*/ 9712unsigned char *sqlite3_serialize( 9713 sqlite3 *db, /* The database connection */ 9714 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 9715 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 9716 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 9717); 9718 9719/* 9720** CAPI3REF: Flags for sqlite3_serialize 9721** 9722** Zero or more of the following constants can be OR-ed together for 9723** the F argument to [sqlite3_serialize(D,S,P,F)]. 9724** 9725** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 9726** a pointer to contiguous in-memory database that it is currently using, 9727** without making a copy of the database. If SQLite is not currently using 9728** a contiguous in-memory database, then this option causes 9729** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 9730** using a contiguous in-memory database if it has been initialized by a 9731** prior call to [sqlite3_deserialize()]. 9732*/ 9733#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 9734 9735/* 9736** CAPI3REF: Deserialize a database 9737** 9738** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 9739** [database connection] D to disconnect from database S and then 9740** reopen S as an in-memory database based on the serialization contained 9741** in P. The serialized database P is N bytes in size. M is the size of 9742** the buffer P, which might be larger than N. If M is larger than N, and 9743** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 9744** permitted to add content to the in-memory database as long as the total 9745** size does not exceed M bytes. 9746** 9747** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 9748** invoke sqlite3_free() on the serialization buffer when the database 9749** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 9750** SQLite will try to increase the buffer size using sqlite3_realloc64() 9751** if writes on the database cause it to grow larger than M bytes. 9752** 9753** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 9754** database is currently in a read transaction or is involved in a backup 9755** operation. 9756** 9757** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 9758** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 9759** [sqlite3_free()] is invoked on argument P prior to returning. 9760** 9761** This interface is only available if SQLite is compiled with the 9762** [SQLITE_ENABLE_DESERIALIZE] option. 9763*/ 9764int sqlite3_deserialize( 9765 sqlite3 *db, /* The database connection */ 9766 const char *zSchema, /* Which DB to reopen with the deserialization */ 9767 unsigned char *pData, /* The serialized database content */ 9768 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 9769 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 9770 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 9771); 9772 9773/* 9774** CAPI3REF: Flags for sqlite3_deserialize() 9775** 9776** The following are allowed values for 6th argument (the F argument) to 9777** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 9778** 9779** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 9780** in the P argument is held in memory obtained from [sqlite3_malloc64()] 9781** and that SQLite should take ownership of this memory and automatically 9782** free it when it has finished using it. Without this flag, the caller 9783** is responsible for freeing any dynamically allocated memory. 9784** 9785** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 9786** grow the size of the database using calls to [sqlite3_realloc64()]. This 9787** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 9788** Without this flag, the deserialized database cannot increase in size beyond 9789** the number of bytes specified by the M parameter. 9790** 9791** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 9792** should be treated as read-only. 9793*/ 9794#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 9795#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 9796#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 9797 9798/* 9799** Undo the hack that converts floating point types to integer for 9800** builds on processors without floating point support. 9801*/ 9802#ifdef SQLITE_OMIT_FLOATING_POINT 9803# undef double 9804#endif 9805 9806#ifdef __cplusplus 9807} /* End of the 'extern "C"' block */ 9808#endif 9809#endif /* SQLITE3_H */ 9810